Articles de revues sur le sujet « Sliding sleeve »
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1
Shi, Lei, Xing Jiu Zhong, Jun Wu et Bin Li. « Research on the Technology of RFID Sliding Sleeve ». Applied Mechanics and Materials 496-500 (janvier 2014) : 1552–55. http://dx.doi.org/10.4028/www.scientific.net/amm.496-500.1552.
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There is a very significant application today towards multiple zone fracturing operations in a horizontal well of low permeability reservior all over the world. But the number of the ball seat activated sliding sleeves that can be run in a well is limited because of the design and cant meet the need of volume fracturing in low permeability reservoir; Also the sleeves can only be shifted by CT, which extend the length of the operation and add to the overall costs. This paper introduces a kind of sleeve which is controlled by RFID and meet the need of volume fracturing, the number of sleeves that can be run in a well using this technology is essentially unlimited and can be operated remotely[1-3]. It is eay to operate and no intervention; It is proved by field test that this sleeve is reliable and can meet the field application.
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Shang, Xiao Feng, Yang Wang et Wei Dong Deng. « Sliding Sleeve Fracturing Strength Analysis of the Ball Based on Ansys Workbench ». Applied Mechanics and Materials 423-426 (septembre 2013) : 1914–19. http://dx.doi.org/10.4028/www.scientific.net/amm.423-426.1914.
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In the oilfield development, the packer is one of important downhole tool in oilfield drilling technology, and sealing effect of the sliding sleeve fracturing ball system directly affect the packer's sealing performance. Using UG software to establish 3D sliding sleeve fracturing ball and base model. Based on Ansys workbench simulation platform, finite element analysis was carried out on the sliding sleeve fracturing ball, distribution pattern in different materials, and sealing effect. Fracturing experiments were done to verify the accuracy of the simulation analysis and ensure the sliding sleeve fracturing system reliability in practical work.
3
Ding, Kun, Jian Min Li, Wen Xin Yang, Jian Hu et Wei Zeng. « Numerical Simulation of Erosion Wear of Liquid-Solid Two-Phase Flow in Sliding Sleeve of Horizontal Well ». Advanced Materials Research 988 (juillet 2014) : 483–88. http://dx.doi.org/10.4028/www.scientific.net/amr.988.483.
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In recent years, the pitching sliding sleeve staged fracturing technology of open hole packer of horizontal well is widely used in shale gas, dense reservoirs, low permeable reservoirs and other exploration and development fields, and becomes the important means of present oil-gas field stimulation. But in the construction process of horizontal well fracturing, the abnormal condition that the sliding sleeve is not opened or is opened invisibly is occurred repeatedly, which has big impact on the fracturing construction. Based on fluid dynamics method and Finnie micro-cutting theory, this paper simulated the erosion wear rate of ball seat at the different fracturing segments. The results showed that: the construction displacement has big impact on the erosion wear, followed by the particle size of proppant and sand ratio, wherein the erosion wear is in inversely proportional to the particle size of proppant; and when multistage fracturing, the possibility that the sliding sleeve close to the toe end and heel happens erosion destruction is much less than that of sliding sleeve in the middle.
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Xu, Daping, Yingxin Yang et Qiming Cheng. « Theoretical and Experimental Research on the Floating-Sleeve Bearing Applied in Roller-Cone Bit ». Shock and Vibration 2019 (26 mars 2019) : 1–11. http://dx.doi.org/10.1155/2019/9719750.
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In oil and gas drilling, the roller-cone bit and the hybrid bit configured with roller cones are two commonly used rock-breaking tools; however, service lives of the bits are limited by the sliding bearings therein. In order to improve the performance and reliability of the bearing in the roller cone, a novel bearing with a floating sleeve is researched in this paper. Firstly, motion characteristics of the bearing are researched, and motion relations between the elements in the bearing are analyzed, respectively. Then, on the basis of the motion relations, three motion statuses of the float sleeve are clarified, including the sleeve start to rotate, the sleeve rotates stably with the pushing force exerted by the rollers, and the sleeve rotates stably with the opposing force exerted by the rollers. At last, bearing performances in three different conditions are respectively tested in the experiment. The results, with the specific speed value being in the range of 0.375∼0.833 and the average value in 0.613∼0.618, show that the sleeves with 6∼12 rollers are able to start and rotate stably under 5 kN radial load, indicating that the sleeves can be started to rotate and work stably, whereas, for the sleeve with less than 4 rollers, the specific speed value varies in the large range of 0∼1.176, indicating that this sleeve cannot rotate stably in the bearing. This research revealed that the amount of rollers is an important factor that determines whether the sleeve is able to float stably in the bearing; therefore, roller quantity should be focused in the bearing design to optimize its performance.
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Wiśniewska-Weinert, H. « Surface Modification Of The High Temperature Porous Sliding Bearings With Solid Lubricant Nanoparticles ». Archives of Metallurgy and Materials 60, no 3 (1 septembre 2015) : 2209–14. http://dx.doi.org/10.1515/amm-2015-0366.
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Abstract A surface modification of stainless steel bearing sleeves is developed to improve the tribology characteristics at high temperature. Solid lubricant nano- and microparticles are applied for this purpose. To create the quasi-hydrodynamic lubrication regimes, the solid lubricant powder layer is made by developed pressure impregnation technique. Porous sliding bearing sleeve prototypes were made by powder metallurgy technique. The purpose of the paper is to define the friction and wear characteristics of the sleeves and to determine the influence of sealing of the sliding interface on these characteristics. It is found that application of WS2 sold lubricant nano- and micro-particles and preservation of a particle leakage out of interface allows to achieve at the high temperature the friction coefficients comparable to those at ambient temperature.
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Yang, Fuqin, Xin Liu, Shun Zhao et Linlin Sun. « Fluid-solid coupling characteristics analysis for tripod sliding universal joints ». Mechanics & ; Industry 20, no 2 (2019) : 201. http://dx.doi.org/10.1051/meca/2019001.
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Fluid-solid coupling theory is introduced into tripod sliding universal joint design. The geometric models of the tripod sliding universal joint and lubricant film are established respectively and meshed. Fluid-solid coupling analyses of tripod sliding universal joints in unidirectional and bidirectional scenarios are performed to investigate sleeve and lubricant film coupling as well as sliding pin and lubricant film coupling under various differential pressures and frequencies. In the condition of unidirectional and bidirectional coupling, sleeve and sliding pin deformation and stress increase gradually with differential pressure and frequency. Under various differential pressures and frequencies, tripod sliding universal joint bidirectional coupling deformation and stress are greater than those of unidirectional coupling. The theory of fluid-solid coupling is combined with the tripod sliding universal joint for the first time in this paper. The fluid-solid coupling analysis results are of great significance and benefit to the design, application and marketing of tripod sliding universal joints.
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Žegarac, Nikola. « Analysis of influencing factors that can cause errors in the application of modern methods of sliding bearing diagnostics in machine and electrical systems ». Vojnotehnicki glasnik 68, no 4 (2020) : 845–76. http://dx.doi.org/10.5937/vojtehg68-27265.
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Introduction/purpose: The paper presents the application of modern methods in the diagnostics of sliding bearings and the analysis of influencing factors that can cause errors in such an application. Possibilities to determine with certainty when and where problems affect sliding bearings during system operation are presented. It is also shown how the system will continue to function over time. Causes of failures and the manner of their elimination are predicted, as well as the time for planned maintenance of technical systems. Method: The new method solves the problem of sliding bearing diagnostics by measuring the dynamic trajectories of the sleeve in the sliding bearing and by measuring vibration parameters on the inner and outer surfaces of the technical system. The dynamic trajectories of the bearing sleeve are measured with non-contact probes; therefore, the centering of probes in relation to the geometric center of the bearing is very important. Vibration parameters, directly related to the clearance in the sliding bearing, are measured on the inner and outer surfaces of the system. The choice of vibration parameters and measuring points is very important. This method has a number of advantages over other diagnostic methods, as it is easy to access measuring points. Results: By measuring the dynamic trajectory of the sleeves in the plain bearing and vibration parameters on the inner and outer surfaces, the bearing clearance quantities are determined, including: normal condition, initial clearance size, its further increase, bearing clearance sizes, and the moment when the condition parameters are close to the upper limit of the permissible bearing clearance. Conclusion: New diagnostic methods and monitoring systems can be widely applied to: internal combustion engines, all piston machines, hydroelectric power plants, thermal power plants, processing plants, and many other systems.
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Li, Ruolan, Dongsheng He et Lang Xiong. « Study on the Cone Angle of Sliding Sleeve Ball Seat in Open Hole Staged Ball Throwing Fracturing ». Academic Journal of Science and Technology 3, no 2 (28 octobre 2022) : 161–66. http://dx.doi.org/10.54097/ajst.v3i2.2162.
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In the ball type fracturing sliding sleeve, the contact surface between the ball socket and the fracturing ball is the most vulnerable part to failure. Once the contact surface fails, the sealing of the fracturing sliding sleeve will fail, the fracturing fluid will leak, and finally the fracturing will fail. The contact condition between the ball socket and the fracturing ball is mainly determined by the cone angle of the ball socket. In order to improve the contact condition between the ball socket and the fracturing ball as much as possible, and extend the service life of the sliding sleeve, based on fluid erosion and finite element structural analysis, this paper has carried out the analysis of the cone angle of the fracturing sliding sleeve. Firstly, the erosion of the ball seat is analyzed, and the erosion rate of the ball seat under different cone angles is obtained. The conclusion is that the erosion rate of the ball seat is proportional to the cone angle of the ball seat. Combined with the working conditions of the ball socket fracturing, the finite element analysis of the ball socket structure is carried out, and the stress conditions of different cone angles are compared. Finally, combined with the erosion rule and force analysis of the ball socket, the optimal cone angle of the ball socket is 20 °. When the cone angle of the ball socket is 20 °, the force of the ball socket meets the strength requirements of the ball socket, and can obtain a higher service life.
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Yang, Fuqin, Jingwei Jiang, Dong Li et Linlin Sun. « Analysis of fluid–solid coupling characteristics of tripod sliding universal coupling based on cavitation and thermal effects ». Advances in Mechanical Engineering 12, no 5 (mai 2020) : 168781402092007. http://dx.doi.org/10.1177/1687814020920073.
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In this article, a fluid–solid coupling analysis of tripod sliding universal coupling and lubricating oil film was conducted by taking into consideration cavitation and thermal effects. The coupling of the sleeve and slip pin with the lubricant oil film under different pressure differences and frequencies was investigated. Moreover, the study results were compared with the results of fluid–solid coupling under the ideal condition of negligible cavitation and thermal effects. When considering these effects, the deformation and stress values of the sleeve and the slip pin gradually increase as the pressure difference and frequency increase. The deformation and stress values of the sleeve are reduced relative to the calculation results of fluid–solid coupling in ideal conditions. However, the values of the slip pin are increased. Furthermore, when considering the thermal effect, the deformation and stress differences for the sleeve and slip pin decrease as the pressure difference increases. The stress difference of the sleeve grows sharply, whereas the deformation difference of the slip pin increases only slightly as the frequency increases.
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CAI, YONGQING. « EFFECTS OF THE INSERTION OF AN ARCHWIRE THIN-WALLED SLEEVE IN ACCELERATING THE CANINE’S TRANSLATION ». Journal of Mechanics in Medicine and Biology 20, no 09 (7 septembre 2020) : 2040009. http://dx.doi.org/10.1142/s0219519420400096.
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In sliding mechanics, resistance to sliding (RS), including friction, binding, and notching, generated at a wire-bracket interface has a bearing on the force transmitted to the teeth and further influences the biomechanical behavior associated with tooth movement efficiency. Objective: This study aimed to propose and verify the insertion of a rectangular thin-walled sleeve between an archwire and a bracket to minimize the resistance effect on the biomechanical behavior of tooth movement by using the finite element (FE) method. Material and methods: A 3D FE solid model was constructed and composed of mandibular dentitions, including the surrounding tooth-supporting structures and fixed self-ligating appliances. The translation of the left mandibular canine was simulated (0.1[Formula: see text]mm and 0.3[Formula: see text]mm) from the labial side to the lingual side with or without the thin-walled sleeve by using eight kinds of archwires with various dimensions and cross-sections by FE methods. Results: FE analysis indicated that the canine’s maximum initial displacement and the highest periodontal ligament (PDL) von Mises stress were mainly influenced by the orthodontic wire and the insertion of the thin-walled sleeve. Without the thin-walled sleeve, rectangular archwires could initiate a more optimal tissue response than round archwires. However, the insertion of the thin-walled sleeve between the small round archwire and the bracket significantly presented the most optimal biological responses in all of the cases. Conclusion: FE results revealed that the insertion of a thin-walled sleeve in a small round archwire and a bracket could have a positive influence on final tooth movement.
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Dal Corso, F., D. Tallarico, N. V. Movchan, A. B. Movchan et D. Bigoni. « Nested Bloch waves in elastic structures with configurational forces ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 377, no 2156 (2 septembre 2019) : 20190101. http://dx.doi.org/10.1098/rsta.2019.0101.
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Small axial and flexural oscillations are analysed for a periodic and infinite structure, constrained by sliding sleeves and composed of elastic beams. A nested Bloch–Floquet technique is introduced to treat the nonlinear coupling between longitudinal and transverse displacements induced by the configurational forces generated at the sliding sleeve ends. The action of configurational forces is shown to play an important role from two perspectives. First, the band gap structure for purely longitudinal vibration is broken so that axial propagation may occur at frequencies that are forbidden in the absence of a transverse oscillation and, second, a flexural oscillation may induce axial resonance, a situation in which the longitudinal vibrations tend to become unbounded. The presented results disclose the possibility of exploiting configurational forces in the design of mechanical devices towards longitudinal actuation from flexural vibrations of small amplitude at given frequency. This article is part of the theme issue ‘Modelling of dynamic phenomena and localization in structured media (part 1)’.
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Bykov, P. A., I. E. Kalashnikov, L. I. Kobeleva, A. G. Kolmakov et R. S. Mikheev. « Investigation of wear conditions of a composite material based on an anti-friction alloy AO20-1 reinforced with Ti particles ». Transaction Kola Science Centre 12, no 2-2021 (13 décembre 2021) : 36–41. http://dx.doi.org/10.37614/2307-5252.2021.2.5.008.
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Сomposite material samples were obtained by the method of reaction casting by mixing titanium particles to obtain intermetallic phases Al3Ti. Dry sliding wear tests were carried out using a fixed sleeve (steel 45) against a rotating disk (sample) at sliding speeds from 0.25 to 0.75 m/s and loads from 0.5 to 3.5 MPa.There were constructed maps of wear rate, which determine the friction modes during testing. There were shown boundaries and conditions of changing wear modes.
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Shinkarenko, Alexey, Yuri Kligerman et Izhak Etsion. « Theoretical Analysis of Surface-Textured Elastomer Sleeve in Lubricated Rotary Sliding ». Tribology Transactions 53, no 3 (16 avril 2010) : 376–85. http://dx.doi.org/10.1080/10402000903312372.
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Ułanowicz, Leszek. « Identification of Destructive Processes Affecting Hydraulic Servomechanisms of the Aircraft Control Assist System ». Solid State Phenomena 180 (novembre 2011) : 238–49. http://dx.doi.org/10.4028/www.scientific.net/ssp.180.238.
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The paper presents identification of destructive processes that affect hydraulic servomechanisms of the aircraft control assist system and influence of these processes onto values of parameters that characterize structures and operation of these systems. Particular attention is paid to the description of essential properties attributable to operation of the distributing device within a hydraulic servomechanism with a spotlight to physical background of the process when friction equilibrium of a sliding hydraulic pair is disturbed, which leads to its destruction. More specifically the issue associated with violation of friction stability in a cylindrical, sliding hydraulic pair due to the impact of an unbalanced radial hydrostatic force as well as material contamination and a hydrodynamic axial force. Qualitative assessment of unbalanced radial forces are carried out for the case when cylindrical slider is placed inside a guiding sleeve with consideration of various positions of the slider against the sleeve. Consequently, a set of parameters was found out with the aim to characterize operation quality (dependability) of a hydraulic servomechanism. Finally, characteristics of a hydraulic servomechanism with a linear distributing slider or a rotary slider have been developed as a function of their lifetime.
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Li, C. G., S. W. Wang et H. Y. Lu. « Modeling of an Elastomeric Friction Damper ». Rubber Chemistry and Technology 82, no 2 (1 mai 2009) : 170–83. http://dx.doi.org/10.5254/1.3548242.
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Abstract Frictional resistance of a hollow rubber cylinder steadily sliding inside a rigid sleeve has been studied theoretically and reported here. This is inspired by a new class of elastomeric friction damper consisting of an unbonded rubber cylinder, axially compressed and radially expanding to contact an outer rigid sleeve and generate friction. By considering the force equilibrium of each thin section of the rubber cylinder and adapting the principle of superposition, the tri-bological problem was decomposed into three fundamental sub-problems, which were solved consecutively. The results shed lights on the functional effects of various design parameters such as part dimensions, friction coefficient, and Young's modulus on the total friction force. Finite element analyses were also performed, and the results were compared with the closed-form solutions.
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Zjakić, Igor, Ivana Ljevak et Albulena Bilalli. « Correlation between Ink Thickness and "Shrink Sleeve" Flexographic Print Quality at a Stable Friction Coefficient ». Tehnički glasnik 15, no 3 (14 septembre 2021) : 366–70. http://dx.doi.org/10.31803/tg-20201112122712.
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Flexographic technology usage is increasing in recent years. Predicted growth in the technology usage intensifies the demand for improved quality. It is expected that flexographic printing will achieve greater results than ever before. Since this technique is used in the printing of shrink sleeve packaging, it is imperative to meet the technical and economic requirements of the shrink sleeve product. This is primarily to ensure gliding of the white printing material. The amount of white should be as small as possible, making the sliding of the material optimal and the quality of the print better. Therefore, the quality of the printing was measured by changing the conditions of slippage and white color. This research has established a correlation between the thickness of the white layer and the reduction of print quality over thin lines.
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Dikshit, Ashutosh, Amrendra Kumar et Glenn Woiceshyn. « Design to First Deployment : Pressure-Activated Sliding Sleeve for Single-Trip Completion ». SPE Drilling & ; Completion 36, no 02 (12 janvier 2021) : 459–72. http://dx.doi.org/10.2118/203057-pa.
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Summary Interest is high in a method to reliably run single-trip completions without involving complex/expensive technologies (Robertson et al. 2019). The reward for such a design would be reduced rig time, safety risks, and completion costs. As described herein, a unique pressure-activated sliding side door (PSSD) valve was developed and field tested to open without intervention after completion is circulated to total depth (TD) and a liner hanger and openhole isolation packers are set. A field-proven sliding-sleeve door (SSD) valve that required shifting via a shifting tool run on coiled tubing, slickline (SL), or wireline was upgraded to open automatically after relieving tubing pressure once packers (and/or a liner hanger) are set. This PSSD technology, which is integrable to almost any type of sand control screen, is equipped with a backup contingency should the primary mechanism fail to open. Once opened, the installed PSSDs can be shifted mechanically with unlimited frequency. The two- or three-position valve can be integrated with inflow control devices (ICDs) (includes autonomous ICDs/autonomous inflow control valves) and allows mechanical shifting at any time after installation to close, stimulate or adjust ICD settings. After a computer-aided design stage to achieve all the operational/mechanical requirements, prototypes were built and tested, followed by field installations. The design stage provided some challenges even though the pressure-activation feature was being added to a mature/proven SSD technology. Prototype testing in a full-scale vertical test well proved valuable because it revealed failure modes that could not have appeared in the smaller-scale laboratory test facilities. Lessons learned from the first field trial helped improve onsite handling procedures. The production logging tool run on first installation confirmed the PSSDs with ICDs opened as designed. The second field installation involved a different size and configuration, in which PSSDs with ICDs performed as designed. The unique two- or three-position PSSD accommodates any type of sand control or debris screen and any type of ICD for production/injection. The PSSD allows the flexibility to change ICD size easily at the wellsite. Therefore, this technology can be used in carbonate as well as sandstone wells. Wells that normally could not justify the expense of existing single-trip completion technologies can now benefit from the cost savings of single-trip completions, including ones that require ICD and stimulation options.
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Zhang, Junhui, Meisheng Yang, Bing Xu, Ruqi Ding, Min Cheng et Pengpeng Dong. « A novel intelligent sliding sleeve for shale oil and gas mining equipment ». Journal of Petroleum Science and Engineering 158 (septembre 2017) : 1–10. http://dx.doi.org/10.1016/j.petrol.2017.07.069.
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PEI, Xiaohan, Songbo WEI, Bairu SHI, Zejun SHEN, Xinzhong WANG, Zheng TONG et Tao FU. « Disintegrating fracturing ball used in ball injection sliding sleeve for staged fracturing ». Petroleum Exploration and Development 41, no 6 (décembre 2014) : 805–9. http://dx.doi.org/10.1016/s1876-3804(14)60097-5.
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Balakin, V. F., S. L. Stasevskyi, V. D, Dobriak et Yu D. Uhriumov. « Improving the preparation of the liner for rolling on the pilger mill ». Metallurgicheskaya i gornorudnaya promyshlennost, №4, 2018, no 4 (août 2018) : 39–44. http://dx.doi.org/10.33101/s04-38748594.
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Purpose. Based on the analysis of the features of the hot piligrim pipe rolling process, develop a new and improved method for preparing liners on the mandrel by compressing their hind ends with specialized strikers of a horizontal hydraulic press. Metodology. The solution to the problem of determining the average specific application on the contact of the liner with the mandrel during compression of its rear end by specialized press dies using the method of slip lines. Findings. The article presents the results of a theoretical determination of the average specific pressure and the width of the contact surface area between the sleeve and the mandrel when the rear end of the sleeve is compressed by specialized strikers of a horizontal hydraulic press. The results obtained allow us to determine the conditions for preventing the liner from slipping from the mandrel as they move toward the rollers in the braking phase. Originality. The main factors affecting the adhesion of the liner to the mandrel were determined, and the values of average specific pressures on the contact of the metal with the mandrel were calculated during the reduction by the profile dies, as well as the width of the contact area and the required thickness of the dies. It has been established that the thickness of the strikers of a double-sided press can be assumed to be the same for all sizes of sleeves of the assortment TPA 5-12 ''. Practical value. The results of the theoretical studies can be used to modernize and reconstruct a section of the off-site charging of a pilger mill TPA 5-12 '' by installing horizontal hydraulic presses with double-die profile dies. This will increase the productivity of the mill by preventing the sleeve from sliding down the mandrel during roll-up to the rolls by creating the necessary adhesion forces between the sleeve and the mandrel. In addition, it will facilitate the conditions of the seed regime piligrim rolling, which will reduce machine time and increase productivity. Key words: pipe, liner, pilgrim mill, hydraulic press, hammer head, mandrel, performance.
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Efendi, Hasrul, Adi Pratama Putra et Dewi Sartika. « Kalibrasi Pompa Injeksi Tipe In-Line Dalam Persamaan Volume Bahan Bakar Motor Diesel 4 Silinder ». V-MAC (Virtual of Mechanical Engineering Article) 6, no 1 (20 avril 2021) : 15–21. http://dx.doi.org/10.36526/v-mac.v6i1.1150.
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Injector is an important component in the diesel engine fuel injection system. This study aims to obtain the results of the in-line type injection pump calibration in the equation of the fuel volume of a 4 cylinder diesel motor. The research was conducted by making simple calibration equipment. Experiments were carried out for 200-300 rpm, 350-450 rpm and 550-600 rpm experimental apparatus rotation speed. Measurements are made for the volume of fuel using a measuring cup. Injection pump calibration is done by loosening the lock on the sleeve then sliding the sleeve to the left or right on each plunger to get fuel volume similarity. The results of data collection before calibration showed the volume of fuel was 26 ml, 30 ml, 30 ml, and 28 ml.
Keywords: calibration, injecton pump, in-line, diesel engine
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CZABAN, Adam. « CFD ANALYSIS OF THE HYDRODYNAMIC LUBRICATION OF A MISALIGNED, SLIDE CONICAL BEARING ». Tribologia 268, no 4 (31 août 2016) : 41–53. http://dx.doi.org/10.5604/01.3001.0010.6977.
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The lateral loads carried by hydrodynamic bearings, and also their uneven distribution, introduce an additional axial misalignment between the shaft and sleeve. The machining and mounting errors also result in improper initial alignment of bearing shaft or sleeve. Furthermore, due to vibrations, misalignment of shaft fluctuates during the operation of the bearing. This has an impact on the operating parameters of the bearing, and, in extreme cases, where the maximum allowable value of the misalignment is exceeded, the bearing can be damaged. The aim of this work is to investigate the effect of misalignment on the hydrodynamic pressure distribution in the conical sliding bearing lubrication gap and on the bearing load carrying capacity and friction force values. This paper shows the result of a CFD simulation of hydrodynamic conical bearings lubrication with the assumption that the bearings are misaligned, i.e. where the rotation axis of bearing shaft is not parallel to the axis of the cone of the bearing sleeve. The commercial CFD software ANSYS Fluent was used in this research. It was assumed that the flow of lubricating oil is laminar, without slipping on bearing surfaces, and that the oil has non-Newtonian properties.
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Carpenter, Chris. « Adjustable Cone Meter Adapts Automatically to Wet-Gas Conditions ». Journal of Petroleum Technology 74, no 12 (1 décembre 2022) : 61–63. http://dx.doi.org/10.2118/1222-0061-jpt.
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_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 207505, “Using an Adjustable Cone Meter To Measure Wet Gas,” by Sakethraman Mahalingam, SPE, Saudi Aramco; Gavin Munro, SPE, GM Flow Measurement; and Muhammad Arsalan, SPE, Saudi Aramco, et al. The paper has not been peer reviewed. _ A traditional fixed-size Venturi meter has a turndown of approximately 8:1 under dry-gas conditions that may drop to as low as 3:1 under wet-gas flow. When the well conditions change, a replacement of the original Venturi meter with one of a different size is needed. In the complete paper, the authors present the design, development, and testing of an adjustable cone meter that has the ability to adapt itself to flow conditions automatically and provide a turndown of as much as a 54:1 under dry-gas conditions and as much as 20:1 under wet-gas conditions. Adjustable Cone Meter Design The adjustable cone meter is a variation on a traditional differential pressure cone meter. A moveable sleeve is placed within the meter, and its position is moved using a rack-and-pinion arrangement. When the flow rate is high (Fig. 1a), the sleeve is downstream of the cone and the meter operates like a normal cone meter. This means that the differential pressure at the cone (P1–P2) is sufficiently high and within the measurable range of the meter. When the flow rate drops below a preset value, however, the differential pressure (P1–P2) drops below the measurable range of the meter. While a conventional cone meter would be unable to measure such flow rates, the adjustable cone meter is able to achieve accurate measurements because the meter detects that the differential pressure is below the measurable range and moves the sleeve automatically so that it covers the cone (Fig. 1b). This reduces the internal diameter of the flowline around the cone and causes the differential pressure to move into the measurable range. The meter then uses the differential pressure to again produce accurate flow measurements. In addition, the meter has a second differential pressure sensor downstream of the cone. This is used to measure the liquid fraction of the wet gas. Meter Design Exhaustive finite-element analysis (FEA) was conducted to determine the operating stresses within the meter body and its pressure-containing components during operation. The sliding sleeve can maintain full line pressure and features double-pressure seals at either end, safely containing fluids inside the flowline. The primary risk is the deformation and failure of the sliding sleeve because it is a thin metal structure. However, FEA established the minimum working pressure of at least 1,200 psi for the sleeve, gearbox, and meter body, using industry-standard safety factors. Cone meter calculations are provided in the complete paper.
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Lv, Zhendong, Yiming Han, Rui Zhang et Jing Wang. « Occurrence of Grease Lubricated Impact-Sliding Composite Wear ». Lubricants 10, no 11 (28 octobre 2022) : 284. http://dx.doi.org/10.3390/lubricants10110284.
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In industrial chain drives, the sleeve slides on the pin and impact loading occurs due to the polygon effect, while the collision between the ball and cage usually produces an impact-sliding motion in the rolling element bearings. Aiming at addressing the occurrence of surface damage caused by the impact-sliding motion, a ball–disk test rig employing optical interference technology was designed and built to realize load variation. Two kinds of commercial grease types, Klüber Centoplex 3 and Centoplex 2EP, were used in the experiments when the glass disk slides at a constant speed while the steel ball collides into them. The sliding and impact motions were controlled by PLC programming. After the experiments, the mid-section grease film distributions were measured using DIIM software. The results show that surface damage can rapidly occur even in the first working cycle, and that the phenomenon is affected by the sliding speed, maximum load, and grease consistency. When the sliding speed is low, multiple contacts of asperity peaks occur in the interior contact region and develop into adhesive wear. When the sliding speed increases, surface wear starts to occur at the side-lobe position of the elastohydrodynamic lubrication (EHL) horseshoe shape and extends with time accompanied by obvious surface scratches. The wear mechanism investigated provides valuable visible information for the further exploration of impact-sliding composite wear. It is suggested that great attention should be paid to impact-sliding wear occurring with grease lubrication since such working conditions are very common in industrial applications.
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Ananth, S., et T. V. Moorthy. « Dry Sliding Wear Behaviour of Titanium and Boron Carbide Nano Coated Grey Cast Iron Cylinder Liner ». Applied Mechanics and Materials 592-594 (juillet 2014) : 1291–95. http://dx.doi.org/10.4028/www.scientific.net/amm.592-594.1291.
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Among several nanocoatings, Ti and B4C hard coating shows excellent wear performance in cutting tool operation. This hard nanocoating Implemented on GCI substrate using EB-PVD coating is to make them suitable for engine components and to act as a protective coating against surface wear and reduce the wear of the components. The wear test was conducted using Pin-on-disc equipment at the room temperature and surface roughness was measured using surface roughness tester.The wear parameters such as sliding speed and sliding distance were kept constant and the load is varied. Coating hardness was measured using Brinell hardness tester.The investigation shows that Ti, B4C coatings have significant effect on GCI sleeve. Also, the result shows that the coating of Ti, B4C improved the wear resistance of the grey cast iron.
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Zheng, Yong Zhen, Ruan Jian et Yong He. « Performance Simulation and Analysis of New High-Frequency Valve ». Advanced Materials Research 219-220 (mars 2011) : 1712–15. http://dx.doi.org/10.4028/www.scientific.net/amr.219-220.1712.
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This article described the design idea, advantages and operation principle of the new high-frequency valve, designed and analyzed its mathematical model. The rotary motion and axial sliding of valve core are used to realize the independence control of excitation frequency and amplitude. The high-frequency excitation can be achieved by increasing in the number of spool table and selecting the matching relationship between the spool and sleeve valve to improve the spool valve cover window grooves and the communication times per revolution.
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Wang, Xingming, Hua Wang, Yukun Fu, Haosheng Liu et Ping Chen. « A novel bypass downlink system for casing sliding sleeve and its laboratory verification ». Journal of Petroleum Science and Engineering 201 (juin 2021) : 108343. http://dx.doi.org/10.1016/j.petrol.2021.108343.
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Zhang, Yanjun, Hongxin Zhang, Jingzhou Yang, Qinghai Zhao, Xiaotian Jiang, Qianchang Cheng et Qingsong Hua. « Research on Distribution of Flow Field and Simulation of Working Pulsation Based on Rotating-Sleeve Distributing-Flow System ». Modelling and Simulation in Engineering 2017 (2017) : 1–9. http://dx.doi.org/10.1155/2017/1015494.
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To solve problems of leakage, vibration, and noise caused by disorders of flow field distribution and working pulsation in the rotating-sleeve distributing-flow system, governing equations of plunger and rotating sleeve and computational fluid dynamics (CFD) model are developed through sliding mesh and dynamic mesh technology to simulate flow field and working pulsation. Simulation results show that the following issues exist: obviously periodic fluctuation and sharp corner in flow pulsation, backward flow when fluid is transformed between discharge and suction, and serious turbulence and large loss in kinetic energy around the damping groove in transitional movements. Pressure in the pump chamber rapidly rises to 2.2 MPa involving over 10% more than nominal pressure when the plunger is at the Top Dead Center (TDC) considering changes about damping groove’s position and flow area in two transitional movements. Shortly pressure overshoot gradually decreases to a normal condition with increasing flow area. Similarly, pressure in the pump chamber instantaneously drops to a saturated vapor pressure −98.9 KPa when the plunger is at the Bottom Dead Center (BDC). With increasing flow area the overshoot gradually increases to the normal condition. This research provides foundations for investigating flow field characteristic and structure optimization of rotating-sleeve distributing-flow system.
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Phungpaingam, Boonchai, Lawrence N. Virgin et Somchai Chucheepsakul. « Snap-Through Phenomenon and Self-Contact of Spatial Elastica Subjected to Mid-Torque ». International Journal of Applied Mechanics 07, no 04 (août 2015) : 1550057. http://dx.doi.org/10.1142/s175882511550057x.
Texte intégralRésumé :
This paper presents the snap-through phenomenon and effect of self-contact of the spatial elastica subjected to mid-length torque. One end of the elastica is clamped while the other end is placed in a sleeve joint. The total arc-length of the elastica can be varied by sliding the end through the sleeve joint. At a certain value of total arc-length, the sleeve joint is clamped and an external torque is applied at the mid-length of the elastica. The system of governing differential equations is derived from the equilibrium of an elastica segment and geometric relations of the inextensible elastica. The transformation matrix formulated in terms of Euler parameters is utilized to avoid the kinematic singularity. To display the behavior of the elastica, the system of differential equations needs to be integrated numerically from one end to the other end. The integration is performed so that the boundary conditions and some constraint conditions of the problem are satisfied, i.e., a shooting method is used. The effect of self-contact is taken into account by considering the contact force as a point load applying at contact point. From the results, the snap-through phenomenon, effect of self-contact and equilibrium configurations are highlighted herein.
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Pan, Xu Dong, Guang Lin Wang, Ze Sheng Lu et Zhen Hua Liu. « Simulation Research on Effect of Diametral Clearance of Spool Valve to Valve Orifice Discharge Characteristic ». Key Engineering Materials 392-394 (octobre 2008) : 184–88. http://dx.doi.org/10.4028/www.scientific.net/kem.392-394.184.
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This paper studies the effect of spool valve diametral clearance of electro-hydraulic servo valve on orifice discharge characteristic. To ensure that the freely sliding between spool and sleeve, there must be given diametral clearance between spool and sleeve, which will have an impact on valve orifice discharge characteristic, this paper first individually sets up a 3D models of clearance from 0 to 5 μm, opening value from 0 to 40 μm, then calculates each model’s discharge on the condition that valve orifice’s inlet and outlet differential pressure is constant, finally according to the result of the discharge plots the diametral clearance curve of spool valve. The quantitative numerical relationship of diametral clearance and spool valve characteristic index is given after doing the analysis, Finally, an experimental verification of the simulation results is to be done to prove the simulation results are correct and reliable. The research of this paper provides the basic guidelines for spool valve designing and testing.
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Liang, Qiong, Bing Zhao Gao et Hong Chen. « Gear Shifting Control for Pure Electric Vehicle with Inverse-AMT ». Applied Mechanics and Materials 190-191 (juillet 2012) : 1286–89. http://dx.doi.org/10.4028/www.scientific.net/amm.190-191.1286.
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In this study, the gear shifting control strategy for pure electric vehicle with inverse automated manual transmission (I-AMT) is proposed. Based on a new drive train system of pure electric vehicle, an AMESim model of vehicle drive-train system is set up. Through the precise control of sliding sleeve, clutch engagement and separating time, gear shifting process is realized without driving torque interruption. The results show that, during up and down shift process, the driving torque keeps more than 50%, obviously improve the pure electric vehicle accelerating performance and the ability to climb.
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Aulin, V. V., S. V. Lysenko, A. V. Hrynkiv et M. V. Pashynskyi. « Improvement of tribological characteristics of coupling parts "shaft-sleeve" with polymer and polymer-composite materials ». Problems of Tribology 27, no 3/105 (26 septembre 2022) : 96–107. http://dx.doi.org/10.31891/2079-1372-2022-105-3-96-107.
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The article provides an analytical justification of the flow of tribological processes of coupling of "shaft-sleeve" parts, which simulates the functioning of sliding bearings and cylindrical joints of machines. The main attention is paid to such characteristics as contact pressure, static and dynamic forces, the criterion of the product of the total pressure on the sliding speed, the work of friction forces and its transition into thermal energy in the friction zone for polymer (based on polyamide P-68) and polymer-composite coatings (based on P-68 with kaolin filler) on the working surfaces of the parts. A comparative analysis of the functioning and tribological characteristics of the couplings of parts without coatings is presented.
Experimentally, on the basis of tests of samples on the MИ-1M friction machine, a significant reduction in wear and an increase in the relative wear resistance of samples with polymer-composite coatings in the modes of friction without lubrication (by 1.3...1.4 times) and marginal friction (in 1.2...1.3 times), as well as a decrease in the temperature in the friction zone (365 K and 347 K) compared to the polymer coating.
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Yang, Huanqiang, Ruihe Wang, Weidong Zhou, Luopeng Li et Fei Chen. « A study of influencing factors on fracture initiation pressure of cemented sliding sleeve fracturing ». Journal of Natural Gas Science and Engineering 18 (mai 2014) : 219–26. http://dx.doi.org/10.1016/j.jngse.2014.03.002.
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Magar, Sandesh. « A Review on Improvement of Hydrodynamic Journal Bearing by using Bio-Lubricant ». International Journal for Research in Applied Science and Engineering Technology 9, no VI (15 juin 2021) : 1052–55. http://dx.doi.org/10.22214/ijraset.2021.35162.
Texte intégralRésumé :
Journal bearings typically consists of metal sleeve that fits around a shaft. The sleeve is held in place within a housing. The journal is simply place on the shaft that is surrounded and supported by the bearing. Journal bearings can be made out of metallic or non-metallic materials such as bronze, aluminium etc. Bearings are generally made out of material that is softer than the metal of the shaft. Journal bearings typically consists of metal sleeve that fits around a shaft. The sleeve is held in place within a housing. The journal is simply place on the shaft that is surrounded and supported by the bearing. Journal bearings can be made out of metallic or non-metallic materials such as bronze, aluminium etc. Bearings are generally made out of material that is softer than the metal of the shaft. Typically, journal bearings are used in various applications such as turbines, compressors, centrifugal pumps etc. The performance of hydrodynamic journal bearing is depend upon the lubrication. Lubrication provides a thin film between internal sliding surfaces of the bearing components to reduce friction. Nowadays crude oil uses increases day by day. Due to depletion of petroleum resources, increasing its price and environmental pollution interest is developed towards the use of economical, environment-friendly lubricants. Bio-lubricants are made from vegetable oils. They are environment-friendly, non-toxic and also having performance benefits such as high viscosity index, high lubricity, high load carrying capacities, rapid biodegradability etc. In this review paper, to improve performance of hydrodynamic journal bearing and also to replace petroleum oil different types of bio-lubricants were examined.
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Han, Chuanjun, et Jie Zhang. « Interference Assembly and Fretting Wear Analysis of Hollow Shaft ». Scientific World Journal 2014 (2014) : 1–9. http://dx.doi.org/10.1155/2014/919518.
Texte intégralRésumé :
Fretting damage phenomenon often appears in the interference fit assembly. The finite element model of hollow shaft and shaft sleeve was established, and the equivalent stress and contact stress were computed after interference assembly. The assembly body of hollow shaft and shaft sleeve was in whirling bending load, and the contact status (sticking, sliding, and opening) and the distribution of stress along one typical contact line were computed under different loads, interferences, hollow degrees, friction coefficient, and wear quantity. Judgment formula of contact state was fixed by introducing the corrected coefficientk. The computation results showed that the “edge effect” appears in the contact surface after interference fit. The size of slip zone is unchanged along with the increase of bending load. The greater the interference value, the bigger the wear range. The hollow degree does not influence the size of stick zone but controls the position of the junction point of slip-open. Tangential contact stress increases with the friction coefficient, which has a little effect on normal contact stress. The relationship between open size and wear capacity is approximately linear.
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Denisov, V. A., R. N. Zadorozhniy, I. V. Romanov, N. I. Chumak et O. S. Alexander. « Tribotechnical Properties of Materials for Cultivator Sliding Bearings ». Agricultural Machinery and Technologies 16, no 4 (13 décembre 2022) : 13–18. http://dx.doi.org/10.22314/2073-7599-2022-16-4-13-18.
Texte intégralRésumé :
Agricultural machinery is stated to break down mainly due to the wear of structural parts. Thus, there is a necessity to apply new materials for manufacturing individual machine units whose characteristics will not be inferior to those of their prototypes. The paper primarily focuses on the components that work in movable joints, in particular, on the sleeve type bronze plain bearings which are exposed to high wear and often need replacing. The use of polymers for manufacturing such parts is supposed to solve the problem of untimely failure of machine components. (Research purpose) To compare the tribotechnical properties of cultivator sliding bearings made of bronze and polyamide. (Materials and methods) Two samples were made: one was made of the sliding bearing (BrO10F1 grade bronze) of the SunGarden GT10 cultivator, the other – of a PA-6 polyamide type rod. Special equipment was used such as: X-ray fluorescence spectrometer Thermo Scientific Niton XL3t 900 GOLDD+, TRB-S-DE Tribometer CSM Instruments. (Results and discussion) Comparative tribotechnical ball-disk tests were carried out. It was found out that polyamide sample has certain advantages over a bronze standard: it has a 4-times better friction coefficient and a 12-times better wear intensity. (Conclusions) It was determined that the use of polymer plain bearings will result in 2 times longer service life of agricultural cultivators and their 1.5 times increased efficiency.
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Pesiridis, Apostolos, et Ricardo F. Martinez-Botas. « Experimental testing of an active control turbocharger turbine inlet equipped with a sliding sleeve nozzle ». Proceedings of the Institution of Mechanical Engineers, Part D : Journal of Automobile Engineering 227, no 6 (10 décembre 2012) : 800–811. http://dx.doi.org/10.1177/0954407012464843.
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Li, Jingyuan, et Zifeng Li. « Applications of the Theory of Continuous Oil Film Lubrication of a Radial Sliding Bearing for Three Combined Conditions ». Applied Physics Research 8, no 2 (15 février 2016) : 22. http://dx.doi.org/10.5539/apr.v8n2p22.
Texte intégralRésumé :
<p class="1Body">The theory of lubrication of a radial sliding bearing is extended to three cases: the shaft neck rotation and bush rotation bearing, the rotating load bearing, and the floating sleeve bearing. For the bearing with rotating shaft neck and rotating bush, fixing the observer at the bushing can enable the determination, in a simple and more accurate manner, of the bearing capacity of the bearing with the rotating load. As long as a rotating load exists, whirl exists; if the shaft rotation speed is 2 times the load rotation speed, then the eccentricity reaches the maximum.</p>
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Melyantsov, P., O. Losikov, V. Nazarets et V. Sidorenko. « Stabilization of the radial clear in the pumping assembly of the supply pump improvement by improving the structure of the slide bearing bushing ». Modern Problems of Metalurgy, no 25 (8 avril 2022) : 102–16. http://dx.doi.org/10.34185/1991-7848.2022.01.09.
Texte intégralRésumé :
The performance of axial-piston hydraulic feed pumps depends on the technical condition of the coupling parts that form a radial gap in the pumping unit of the pump. The dynamics of its growth is largely due to the technical condition of parts that form a radial gap in the plain bearings of the pumping pump assembly: «drive shaft pin - bushing hole», «driven axle pin - bushing hole». Stabilization of a radial backlash in sliding bearings is possible by carrying out constructive improvement of the plug which will provide reduction of a contact angle of surfaces of friction of details in couplings. The aim of the work is to ensure the stabilization of the radial clearance in the pumping unit of the feed pump by developing constructive measures to reduce wear of parts in its plain bearings. From the analysis of the operating conditions of the plain bearing it is established that the reduction of the friction force is possible due to the reduction of the contour pressures and the increase of the area of liquid friction between the surfaces of the parts. Providing such conditions is possible by using combined bushings, which consist of working and guide bushings, between which is installed an elastic damping element in the spherical channels of which are additional compensation springs, which are placed in a circle through . The reduction of the friction force when using a combined sleeve with compensating springs is explained by the formation of the deformation component of the friction force at the vertices of the microroughness of the sleeve surface, as the spring elasticity is 4% less than the modulus of elasticity of the sleeve material. The lower value of the moment of friction forces at the end of the test is due to the constant absorption of vibration loads by the elastic damping element, the elasticity of which is 2% less than the modulus of elasticity of the sleeve material, which also reduces the contact area. The total less wear of the experimental friction pair is due to the reduction of the contact area of the shaft with the sleeve in the area of maximum values of friction forces.
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Zhachkin, Sergey, Nikita Penkov, Sergey Lazarev et Grigory Trifonov. « REGULARITIES OF THE INFLUENCE OF OPERATING PARAMETERS OF SLIDING BEARINGS OF AUTO-TRANSPORT MACHINES ON THE TEM-PERATURE IN THE FRICTION ZONE AS A RESOURCE FACTOR ». Voronezh Scientific-Technical Bulletin 3, no 3 (2 février 2022) : 95–101. http://dx.doi.org/10.34220/2311-8873-2022-95-101.
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The results of the study of the dependence of the temperature of the friction zone of two bodies (shaft and the inner sleeve) are presented from the operational parameters of the sliding bearing, such as pressure, slip speed and radial load in the resource aspect of the friction pair. On the basis of a multi-factor experiment, the regression of the friction process was obtained, which takes into account the influence of these parameters on the temperature in the contact zone, which makes it possible to determine the borders of the trouble-free operation of the friction of motor vehicles. Technological ways are proposed to solve the problematic performance of the friction pair on the temperature criterion without scoring.
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Rank, Martin, Dominik Meffert, Manuel Oehler et Oliver Koch. « Einfluss von Beschichtungen zur triboaktiven Transferschichtbildung auf die Reibung in Kettengelenken ». Tribologie und Schmierungstechnik 69, no 5-6 (15 février 2023) : 5–12. http://dx.doi.org/10.24053/tus-2022-0039.
Texte intégralRésumé :
In this work, the friction behavior of chain joints with triboactively coated pins was analyzed. For this purpose, the nitride hard coating (Cr,Al)N+Mo, produced by means of a PVD process, was investigated. A sulfur-added model grease was used for lubrication. This is to produce tribochemical transfer coatings that are transferred from the chain pin to the sleeve under tribological loading. As a reference, measurements were also carried out on a (Cr,Al)N coating system and on uncoated samples. Various normal forces, sliding speeds and temperatures were also considered as further influencing variables. The frictional torques were determined using the chain joint tribometer deve loped at the Chair of Machine Elements, Gears and Tribology (MEGT).
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Kazmierczak, A. « Physical aspects of wear of the piston-ring—cylinder set of combustion engines ». Proceedings of the Institution of Mechanical Engineers, Part D : Journal of Automobile Engineering 222, no 11 (1 novembre 2008) : 2103–19. http://dx.doi.org/10.1243/09544070jauto877.
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The research presented in this paper has shown that the physical aspects of interfacial phenomena, described by the total value of surface free energy and the values of its components, make it possible to select more suitable materials for sliding pairs. The total value of surface free energy depends on the molecular structure and the bonds characteristic of a given material, and determines its hardness. In order to reduce friction losses in a sliding pair that is being designed, it is proposed to match such materials for the pair in such a way that the surface of one of them has a high sum of surface free energy components originating from van der Waals interactions, while the other material's surface has a possibly low value of the sum. Furthermore, proper values of the components of surface free energy ensure proper wettability with lubricating oil. In order to minimize friction in a sliding contact, the element with the larger surface area (e.g. a cylinder sleeve) should have larger dispersion and van der Waals forces compared with those of the oil, while the element with the smaller area (e.g. a piston ring) has to have smaller (as low as possible) dispersion and van der Waals forces compared with those of the lubricating oil. Thus a basis for reducing friction losses, particularly during mixed friction and boundary friction, has been created. Pursuing the practical goal of this research, a new cylinder liner sliding pair of a piston-ring—cylinder (PRC) set (in which the ring has a titanium nitride (TiN) coating and the cylinder liner has a surface layer with varying properties, applied by vacuum nitriding) of a piston packing ring—combustion engine was designed and made. The sliding pair can be used in self-ignition combustion engines and in spark-ignition engines. The sliding pair is the result of the research carried out as part of this paper, including tests in a tribotester and three-stage testing embracing numerical simulations, preliminary tests on the real object, and tests proper on the real object.
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Biryukov, Vladimir, et Anton Princ. « DEFINITION OF TRIBOLOGICAL CHARACTERISTICS OF THE ALUMINUM AND SILICON ALLOY DEPENDING ON THE COMPOSITION OF ADDITIVES FOR DIESEL LOCOMOTIVE PISTON ». Transport engineering 2022, no 7 (5 juillet 2022) : 34–42. http://dx.doi.org/10.30987/2782-5957-2022-7-34-42.
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The study objective is to define the influence of various modifiers on the tribotechnical properties of an aluminum and silicon alloy. Determination of the most optimal additives in alloys that would reduce the friction factor and increase the unit load at which friction pairs set in comparison with the starting material, as well as determination of their wear resistance.
Research methods are tests conducted for friction and wear of samples based on aluminum and silicon according to the following: plane (test sample) – the sleeve end (steel 40X), as well as conducting tests with the supply of free abrasive into the friction zone according to the following: flat sample - forming surface of a rubber disc.
Research results and novelty: the influence of modifiers in the aluminum and silicon alloy composition on wear resistance and friction ratio at different loads and sliding speeds in a friction pair with steel are established.
Conclusions: the regularities of changes in the friction ratio from pressure and speed, the load of seizure from the sliding speed are obtained. The wear resistance of samples with various inclusions is higher compared to the base material.
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Piątkowska, Ewa. « Influence of solid particle contamination on the wear process in water lubricated marine strut bearings with NBR and PTFE bushes ». Polish Maritime Research 28, no 4 (1 décembre 2021) : 167–78. http://dx.doi.org/10.2478/pomr-2021-0059.
Texte intégralRésumé :
Abstract This paper reports on a study of the influence of solid particle contamination on the wear process in water-lubricated slide bearings (steel-acrylonitrile-butadiene rubber (NBR) and steel-polytetrafluoroethylene (PTFE)). To compare the wear of the shaft journal and bushes (NBR and PTFE) when lubricated with fresh water and contaminated water, an experiment was carried out to identify key factors that influence the state of wear of slide bearing. The amount of wear was checked by means of geometric structure measurements on the journals, namely, roughness profile measurements using both a contact profilometer and an optical microscope. The obtained results enabled correlations between the material comprising the sliding sleeve, roughness of the journals and contamination inside the water-lubricated slide bearings.
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Dmytrychenko, Mykola, et Ivan Bogdanov. « CAUSES OF DESTRUCTION DURING OIL STARVING IN THE FRICTION COUPLE "PISTON RING - CYLINDER LINER" ». Collected scientific works of Ukrainian State University of Railway Transport, no 200 (17 juin 2022) : 6–10. http://dx.doi.org/10.18664/1994-7852.200.2022.262663.
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The study deals with the phenomenon of wear in the friction pair of the piston ring -cylinder liner during bench tests on prototypes. The tribological performance of dry frictionsimulating oil starvation was evaluated using the reciprocating motion of the tribometer. Significantwear was observed on the surface of the sleeve, made of gray cast iron, in contact with the chromesteel surface. This can be explained by a significant gradient in the rigidity of the tribopair inconjugation. With a chrome coating that has a noticeable hardness, extrusion and foaming of thesurface are observed along the edge of the sleeve, which indicates a change in wear. The coefficientof friction in dry sliding with stepped load increases showed an unstable state of friction, which isnot appreciated in the operation of any tribological system.Piston rings are used to seal the exhaust outlet gap between the piston and the liner for efficientoperation of the internal combustion engine. The distribution surface of the cylinder liner and pistonring during reciprocating motion is subject to continuous wear due to constant stresses, hightemperatures and intense loads. Thus, the performance and reliability of such heavy-duty enginecomponents depend on the topography of the conjugate surfaces and the associated tribologicalinteractions. Therefore, it is necessary to study the tribological behavior of conjugates of liners -rings that are subject to wear during oil starvation, and designed to effectively prevent exfoliation.This phenomenon leads to new surface coatings and modifications with significant wear propertiesin difficult operating conditions. Under certain conditions of loading, sliding and lubrication, the temperature rises to a criticalstate, the formation of the lubricating film is stopped and any formed lubricating film is destroyed,which leads to a catastrophic increase in friction. This continuous thermal feedback with the contactzone leads to wear of the friction pair of the piston ring - the cylinder liner. Given the changes in thedesign and materials of the engine, despite the fact that engine performance has increasedsignificantly with reduced emissions, it is impossible to exclude increased performance and enginefailure.
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He, Zhenzhi, Xiaodong Yan, Yuan Sun, Wei Wang, Gongbo Zhou, Ping Zhou, Chaoquan Tang et Fan Jiang. « A Novel Wear Detection Method Based on FPC : A Case Study on the Hoisting Cage Sliding Sleeve ». IEEE Transactions on Instrumentation and Measurement 70 (2021) : 1–11. http://dx.doi.org/10.1109/tim.2021.3082265.
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Barrot, A., M. Sartor et M. Paredes. « Investigation of torsional teeth stiffness and second moment of area calculations for an analytical model of spline coupling behaviour ». Proceedings of the Institution of Mechanical Engineers, Part C : Journal of Mechanical Engineering Science 222, no 6 (1 juin 2008) : 891–902. http://dx.doi.org/10.1243/09544062jmes828.
Texte intégralRésumé :
Torque distribution from within spline coupling is an important matter for design engineers, who wish to study the behaviour of spline couplings. This distribution can be estimated because of an analytical equation, based on material, torsional teeth stiffness, and second moments of area of the shaft and sleeve. These parameters have to be determined precisely. The material properties can be readily determined but calculation of the other parameters requires finite-element calculations or complex algorithms. The aim is to propose simplified equations so as rapidly to obtain values for both teeth stiffness and second moments of area. Experimental designs were implemented to determine the most appropriate equations. Torsional stiffness is the first parameter studied in the present paper. This is the result of rotations due to various phenomena involving distortions such as bending, shear, compression, rotation of the foundation of the teeth, and the teeth sliding. Two simplified equations are finally expressed to define torsional stiffness. The first equation takes into account the first four phenomena and the second one the teeth sliding. The second topic in the present paper covers the influence on torque distribution of various formulae for calculating second moments of area. A solution, which takes into account the shear of the teeth, is highlighted.
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Pilyushina, G. A., P. G. Pyrikov, E. A. Pamfilov, A. Ya Danilyuk et V. V. Kapustin. « Modifying Wood for Creation Plain Bearings of Timber Machines ». Lesnoy Zhurnal (Forestry Journal), no 5 (5 novembre 2020) : 155–65. http://dx.doi.org/10.37482/0536-1036-2020-5-155-165.
Texte intégralRésumé :
The use of modified wood in different friction pairs of timber machines and processing equipment is largely due to its high wear resistance, low coefficient of friction and good dissipative characteristics. The positive properties of composite materials are achieved by using technologies of volumetric modification and implantation of antifriction and heatconducting elements, as well as by forming a composite of crushed wood with the addition of modifying additives and three-dimensional reinforcement. The expansion of the scope of using composite materials in the designs of units with sliding friction pairs necessitates carrying out research on their performance and formation conditions for high level tribotechnical parameters: wear resistance, antifriction, heat resistance, etc. Lack of information on the effect from the factors providing the functional characteristics of wood-based materials including thermal conductivity and vibration absorption significantly complicates the problem analysis in design and technology when developing and producing bearing joints. Therefore, the purpose of this work was studying the conditions of contact interaction of plain bearings made of wood-metal composite materials, allowing for rheological effects, and developing the ways of control their tribotechnical parameters by changing the structure, composition and phase filler. Models of bearings of different types, which allow creating a regulated stress-strain state in sleeves and liners, were developed for these purposes. Research of the bearings performance made it possible to find vibration-damping properties when using suspended crushed fractions in the composite. Increased antifriction properties are achieved in the process of wood modification with electrolytic copper, while the manufacturability of a bearing sleeve is achieved when the support is formed directly at the installation site. Unlike most of the used antifriction materials, the bushings wood maintains the stability of structure in conditions of volumetric compression at negative and positive temperatures, and the wear processes occurring on the contact surfaces of wood-metal bearings are followed by the compaction of the sleeve material. The subsequent destruction is predominantly of fatigue nature, initiated by the dynamics of vibrations and disturbances of the system; therefore, an important part of further research is the assessment of the relaxation ability of wood-metal composites under shock-vibration loading with optimization of their composition according to this criterion.
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Olejnik, Paweł, et Jan Awrejcewicz. « Effectiveness of the Sliding Mode Control in a Two Coupled Discontinuous Dynamical Systems with Dry Friction ». Solid State Phenomena 248 (mars 2016) : 77–84. http://dx.doi.org/10.4028/www.scientific.net/ssp.248.77.
Texte intégralRésumé :
Numerical modeling and a tracking control of angular velocity of a rotor measured in the assumed sliding contact bearing subject to a discontinuous dynamical loading has been performed in this contribution. A contact interface in the direct current motor’s sleeve bearing has been treated as a dynamical system with dry friction, including a few sources of the stick-slip and creep-slip effects. The object of control is subject to an irregularly changing torque generated by another discontinuous dynamical system with friction. The loading comes from a block-on-belt model of a conveyer system with intensification of friction force, which has been elastically coupled with the direct current rotor’s shaft by means of the transmission belt. Therefore, the dynamic loading of the DC motor changes because of time-varying linear velocity of two belts. If such additional torque oscillates while the rotational velocity of the motor’s shaft is small due to a requirement, then it significantly affects the entire system’s dynamics producing stronger nonlinear response of the motor’s speed.
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Lye, Tiffany Jian Ying, Kiat Rui Ng, Alexander Wei En Tan, Nicholas Syn, Shi Min Woo, Eugene Kee Wee Lim, Alvin Kim Hock Eng, Weng Hoong Chan, Jeremy Tian Hui Tan et Chin Hong Lim. « Small hiatal hernia and postprandial reflux after vertical sleeve gastrectomy : A multiethnic Asian cohort ». PLOS ONE 15, no 11 (6 novembre 2020) : e0241847. http://dx.doi.org/10.1371/journal.pone.0241847.
Texte intégralRésumé :
Background Laparoscopic vertical sleeve gastrectomy (LSG) is a popular bariatric procedure performed in Asia, as obesity continues to be on the rise in our population. A major problem faced is the development of de novo gastroesophageal reflux disease (GERD) after LSG, which can be chronic and debilitating. In this study, we aim to assess the relationship between the presence of small hiatal hernia (HH) and the development of postoperative GERD, as well as to explore the correlation between GERD symptoms after LSG and timing of meals. In doing so, we hope to gain a better understanding about the type of reflux that occurs after LSG and take a step closer towards effectively managing this difficult to treat condition. Methods We retrospectively reviewed data collected from patients who underwent LSG in our hospital from Dec 2008 to Dec 2016. All patients underwent preoperative upper GI endoscopy, during which the identification of hiatal hernia takes place. Patients' information and reflux symptoms are recorded using standardized questionnaires, which are administered preoperatively, and again during postoperative follow up visits. Results Of the 255 patients, 125 patients (74%) developed de novo GERD within 6 months post-sleeve gastrectomy. The rate of de novo GERD was 57.1% in the group with HH, and 76.4% in the group without HH. Adjusted analysis showed no significant association between HH and GERD (RR = 0.682; 95% CI 0.419 to 1.111; P = 0.125). 88% of the patients who developed postoperative GERD reported postprandial symptoms occurring only after meals, and the remaining 12% of patients reported no correlation between the timing of GERD symptoms and meals. Conclusion There is no direct correlation between the presence of small hiatal hernia and GERD symptoms after LSG. Hence, the presence of a small sliding hiatal hernia should not be exclusion for sleeve gastrectomy. Electing not to perform concomitant hiatal hernia repair also does not appear to result in higher rates of postoperative or de novo GERD.