Journal articles: 'Axial-piston hydraulic machines'

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Burumkulov, F. Kh, P. A. Ionov, A. V. Stolyarov, and A. P. Senin. "A new technology of axial-piston hydraulic machines repair." Traktory i sel hozmashiny 79, no. 9 (September 15, 2012): 50–53. http://dx.doi.org/10.17816/0321-4443-69497.

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Problems of the axial-piston hydraulic machines repair, findings of investigation of parts and their joinings wear are considered. Degree of their influence on the hydraulic pump efficiency coefficient is ascertained. Recommendations on service life determinant parts renewal were developed.

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Soloviov, R. Yu, A. O. Kapustkin, and I. M. Makarkin. "Methods of diagnostics of nonadjustable axial-piston hydraulic machines." Traktory i sel hozmashiny 80, no. 5 (May 15, 2013): 42–45. http://dx.doi.org/10.17816/0321-4443-65891.

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Avrunin, Grygoriy, Valery Shevchenko, Dmitriy Shevchenko, Oleg Shcherbak, Igor Pimonov, and Irina Moroz. "Analysis of the characteristics of axial-piston hydraulic machines for drives for maintenance of airfields and planes." Bulletin of Kharkov National Automobile and Highway University, no. 95 (December 16, 2021): 15. http://dx.doi.org/10.30977/bul.2219-5548.2021.95.0.15.

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Is an integral part of the development of the concept of forming a standard range of transport and technological hydrophilic modular means for maintenance of airfields and aircraft. Goal. Development of scientifically sound recommendations for determining the rational parameters of the hydraulic system with automation of control and energy saving during operation of modular vehicles for maintenance of airfields and aircraft, taking into account the potential of domestic engineering and critical imports of units. Methodology. Analysis of the development of axial-piston pumps and motors according to the manufacturers' catalogs taking into account the needs of modular vehicles for maintenance of airfields and aircraft, in particular, taking into account the creation of modern hydraulic machines by enterprise «Hydrosila» by increasing pressure, speed and development new regulators. Results. It is established that the domestic nomenclature of modern pumps and motors of axial piston type allows to create three-dimensional hydraulic drives with power to 110 kW for transmissions with machine stepless remote electrohydraulic regulation of speed of rotation of wheels of modular vehicles and to 85 kW throttle drives of technological equipment with energy saving systems by using pumps with automatic regulators of change of working volume. It has been established that in the pumps for of transmissions the ratio of mass to power is reduced three times.Originality. Graphic dependences of power, supply and torque of standard size series on the working volume of axial-piston pumps and hydraulic motors of the domestic enterprise "Hydrosila" for volumetric hydraulic transmissions and technological equipment of aerodrome and aircraft maintenance facilities are constructed. Practical value. The possibility of a rational selection of axial-piston domestic hydraulic machines for the development of hydraulic drives for airfields and aircraft.

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Ernst, Meike, Andrea Vacca, Monika Ivantysynova, and Georg Enevoldsen. "Tailoring the Bore Surfaces of Water Hydraulic Axial Piston Machines to Piston Tilt and Deformation." Energies 13, no. 22 (November 17, 2020): 5997. http://dx.doi.org/10.3390/en13225997.

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A novel virtual prototyping algorithm has been developed to design one of the most critical lubricating interfaces in axial piston machines of the swash plate type—the piston–cylinder interface—for operation with water as the working fluid. Due to its low viscosity, the use of water as a lubricant can cause solid friction and wear in these machines at challenging operating conditions. The prototyping algorithm compensates for this by tailoring the shape of the bore surface that guides the motion of each piston in this type of positive displacement machine to conform with the piston surface, taking into account both the piston’s tilt and its deformation. Shaping these surfaces in this manner can render the interface more conducive to generating hydrodynamic pressure buildup that raises its load-carrying capacity. The present work first outlines the structure of the proposed algorithm, then presents a case study in which it is employed to design a bore surface shape for use with two prototypes, one virtual and one physical—both modified versions of a 444 cc commercial axial piston pump. Experimental testing of the physical prototype shows it to achieve a significantly higher maximum total efficiency than the stock unit.

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Kuz'min, A. O., V. V. Popov, and S. M. Stazhkov. "Hydrodynamic processes in the piston and cylinder unit of axial-piston hydraulic machines." Journal of «Almaz – Antey» Air and Space Defence Corporation, no. 4 (December 30, 2017): 86–90. http://dx.doi.org/10.38013/2542-0542-2017-4-86-90.

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The purpose of the research was to analyze the kinematics of the piston mechanism of an axial-piston hydraulic machine with an adjustable-angle cam plate. The kinematic analysis resulted in establishing various types of relative motion of the piston in the guide bushing, writing and solving Reynolds equation with respect to velocities. A sweep method was used to construct a pressure field in the working fluid layer between the piston and the guide bushing. Pressure fields are constructed for several cases of kinematics of the piston mechanism.

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Chiang, Mao Hsiung, Chung Chieh Cheng, Liang Wang Lee, Maoh Chin Jiang, and Jhih Hong Lin. "Signed-Distance Fuzzy Sliding Mode Position Control for an Energy-Saving Electro-Hydraulic Control System." Applied Mechanics and Materials 284-287 (January 2013): 2315–19. http://dx.doi.org/10.4028/www.scientific.net/amm.284-287.2315.

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Electro-Hydraulic pump-controlled servo systems that have high energy-efficiency can serve as energy-saving system. This paper aims to investigate the servo performance of the electro-hydraulic pump-controlled systems driven by an AC servo motor with variable rotational speed. A constant displacement axial piston pump is used in this research. Thus, the new hydraulic pump-controlled system with an AC motor servo and a constant displacement axial piston pump is investigated for position control of hydraulic servo machines. For that, this paper also develops the control strategy, sign-distance fuzzy sliding mode control, which can simplify the fuzzy rule base through the sliding surface. The developed high response variable rotational speed pump-controlled systems controlled by SD-FSMC are implemented and verified experimentally for positioning control in different stroke and loading conditions.

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Jeong, Heon-Sul, and Hyoung-Eui Kim. "On the instantaneous and average piston friction of swash plate type hydraulic axial piston machines." KSME International Journal 18, no. 10 (October 2004): 1700–1711. http://dx.doi.org/10.1007/bf02984318.

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Tkach, Vyacheslav. "INFLUENCE OF WORKING FLUID VISCOSITY ON LUBRICATION MODE OF HYDRAULIC UNITS OF CONSTRUCTION MACHINES." Globus: technical sciences 7, no. 3(39) (August 19, 2021): 3–8. http://dx.doi.org/10.52013/2713-3079-39-3-1.

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The influence of dynamic viscosity of working liquids И-20А, МГЕ-46В, ВМГЗ on the lubrication of plunger pairs of axial-piston pumps of construction equipment is considered in the article. Based on the existing classification of lubricant types, a mathematical model is obtained to determine the effective viscosity, which corresponds to the transition of the plunger pair from the boundary lubrication regime to the semi-liquid mode. The obtained model takes into account the geometric parameters, the speed of rotation of the pump shaft and the size of the dimensionless criterion — the relative thickness of the lubricating film. The calculation of the change in the effective viscosity from the angle of rotation of the shaft for a plunger pair of an axial-piston pump with an inclined disk.

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Baryshev, V. I., and V. V. Panov. "Key deterioration factors of hydrostatic bearings of the axial-piston hydraulic machines." Traktory i sel hozmashiny 80, no. 1 (January 15, 2013): 34–37. http://dx.doi.org/10.17816/0321-4443-65912.

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Formation of porous stoppers in delivery capillaries of hydrostatic bearings and their obliteration are substantiated as secondary factors of bearings deterioration under the impact of working fluids contaminations. Findings of the laboratory investigations are given.

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Babak, Vitalii, and Viatcheslav Stadnychenko. "APPLICATION OF REVITALISANTS FOR EXTENSION OF RESOURCE AND RESTORING WORN‐OUT FRICTION UNITS OF AVIATION AXIAL ‐ PISTON HYDROMACHINES." Aviation 8, no. 1 (March 31, 2004): 8–12. http://dx.doi.org/10.3846/16487788.2004.9635863.

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The perspectives of application of using RVS technique for repairing and prophylactic of hydraulic systems’ units, particularly axial‐piston machines are considered. Physical background of revitalization processes, which took place on the friction surfaces during drifting of cermets coating (CC) are uncovered. The results were received from numerous investiga‐tions.

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Kyzyrov, R. B., I. A. Bondarev, A. N. Sinko, and T. Yu Nikonova. "Determination of the Functional Accuracy of the Piston Pair of Axial Hydraulic Machines." Material and Mechanical Engineering Technology 1, no. 1 (2021): 14–18. http://dx.doi.org/10.52209/2706-977x_2021_1_14.

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Kuzmin, A. O., S. M. Stazhkov, N. V. Tarasova, and P. I. Valikov. "Fractional step method in problems of hydromechanical processes in piston-cylinder unit of axial piston swash plate hydraulic machines." Journal of «Almaz – Antey» Air and Space Defence Corporation, no. 4 (December 30, 2019): 60–66. http://dx.doi.org/10.38013/2542-0542-2019-4-60-66.

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Having analyzed the piston-cylinder unit kinematics, we obtained an equation for the clearance height in the piston-cylinder unit for the case of low speeds, the equation being the basis for Reynolds equation for the lubricant layer of the piston mechanism. By a numerical experiment using the fractional step method, we built a pressure field for two different cases of the piston mechanism kinematics, and compared the bearing capacity of the hydrodynamic force. It was revealed analytically and with the help of a numerical experiment that when the piston rolls in the edges of the guide bushing, the total hydrodynamic force significantly exceeds the force created when the piston slides in the bushing.

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Shang, Lizhi, and Monika Ivantysynova. "Scaling Criteria for Axial Piston Machines Based on Thermo-Elastohydrodynamic Effects in the Tribological Interfaces." Energies 11, no. 11 (November 19, 2018): 3210. http://dx.doi.org/10.3390/en11113210.

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In lieu of reliable scaling rules, hydraulic pump and motor manufacturers pay a high monetary and temporal price for attempting to expand their production lines by scaling their existing units to other sizes. The challenge is that the lubricating interfaces, which are the key elements in determining the performance of a positive displacement machine, are not easily scalable. This article includes an analysis of the size-dependence of these units with regard to the significant physical phenomena describing the behavior of their three most critical lubricating interfaces. These phenomena include the non-isothermal elastohydrodynamic effects in the fluid domain, and the heat transfer and thermal elastic deflection in the solid domain. The performance change due to size variation is found to be unavoidable and explained through fundamental physics. The results are demonstrated using a numerical fluid–structure–thermal interaction model over a wide range of unit sizes. Based on the findings, a guide to scaling swashplate-type axial piston machines such as to uphold their efficiency is proposed.

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Klimek, Agnieszka, Janusz Kluczyński, Jakub Łuszczek, Adam Bartnicki, Krzysztof Grzelak, and Marcin Małek. "Wear Analysis of Additively Manufactured Slipper-Retainer in the Axial Piston Pump." Materials 15, no. 6 (March 8, 2022): 1995. http://dx.doi.org/10.3390/ma15061995.

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Additive manufacturing (AM) of spare parts is going to become more and more common. In the case of hydraulic solutions, there are also some applications of AM technology related to topological optimization, anti-cavitation improvements, etc. An examination of all available research results shows that authors are using specialized tools and machines to properly prepare AM spare parts. The main aim of this paper is to analyze the influence of quick repair of the damaged slipper-retainer from an axial piston pump by using an AM spare part. Hence, it was prepared with a 100-h test campaign of the AM spare part, which covers the time between damage and supply of the new pump. The material of the slipper-retainer has been identified and replaced by another material—available as a powder for AM, with similar properties as the original. The obtained spare part had been subjected to sandblasting only to simulate extremely rough conditions, directly after the AM process and an analysis of the influence of the high surface roughness of AM part on wear measurements. The whole test campaign has been divided into nine stages. After each stage, microscopic measurements of the pump parts’ surface roughness were made. To determine roughness with proper measurements, a microscopical investigation was conducted. The final results revealed that it is possible to replace parts in hydraulic pumps with the use of AM. The whole test campaign caused a significant increase in the surface roughness of the pump’s original parts, which was worked with the AM spare slipper-retainer: (1) from Ra = 0.54 µm to Ra = 3.84 µm in the case of two tested pistons; (2) from Ra = 0.33 µm to Ra = 1.98 µm in the case of the slipper-retainer. Despite significant increases in the surface roughness of the pump’s parts, the whole test campaign has been successfully finished without any damages to the other important parts of the whole hydraulic test rig.

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Pietrzyk, Tobias, Markus Georgi, Sabine Schlittmeier, and Katharina Schmitz. "Psychoacoustic Evaluation of Hydraulic Pumps." Sustainability 13, no. 13 (June 30, 2021): 7320. http://dx.doi.org/10.3390/su13137320.

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In this study, sound measurements of an axial piston pump and an internal gear pump were performed and subjective pleasantness judgements were collected in listening tests (to analyze the subjective pleasantness), which could be seen as the inverse of the subjective annoyance of hydraulic drives. Pumps are the dominant sound source in hydraulic systems. The noise generation of displacement machines is subject of current research. However, in this research only the sound pressure level (SPL) was considered. Psychoacoustic metrics give new possibilities to analyze the sound of hydraulic drive technology and to improve the sound quality. For this purpose, instrumental measurements of the acoustic and psychoacoustic parameters are evaluated for both pump types. The recorded sounds are played back to the participants in listening tests. Participants evaluate them regarding the subjective pleasantness by means of paired comparison, which is an indirect scaling method. The dependence of the subjective pleasantness on speed and pressure was analyzed for both pump types. Different regression analyses were carried out to predict the subjectively perceived pleasantness or annoyance of the pumps. Results show that a lower speed is the decisive operating parameter for reducing both the SPL and the annoyance of a hydraulic pump.

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Nizhegorodov, A. I., A. N. Gavrilin, and B. B. Moyzes. "Analysis of structures, properties and basic indicators of two-row axial piston hydraulic machines with an inclined cylinders block." IOP Conference Series: Materials Science and Engineering 971 (December 1, 2020): 042040. http://dx.doi.org/10.1088/1757-899x/971/4/042040.

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Jasiński, Ryszard. "Problems of the Starting and Operating of Hydraulic Components and Systems in Low Ambient Temperature (Part IV)." Polish Maritime Research 24, no. 3 (September 1, 2017): 45–57. http://dx.doi.org/10.1515/pomr-2017-0089.

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Abstract Designers of hydraulically driven machines and devices are obliged to ensure during design process their high service life with taking into account their operational conditions. Some of the machines may be started in low ambient temperature and even in thermal shock conditions (due to delivering hot working medium to cold components). In order to put such devices into operation appropriate investigations, including experimental ones - usually very expensive and time-consuming, are carried out. For this reason numerical calculations can be used to determine serviceability of a hydraulic component or system operating in thermal shock conditions. Application of numerical calculation methods is much less expensive in comparison to experimental ones. This paper presents a numerical calculation method which makes it possible to solve issues of heat exchange in elements of investigated hydraulic components by using finite elements method. For performing the simulations the following data are necessary: ambient temperature, oil temperature, heat transfer coefficient between oil and surfaces of elements, as well as areas of surfaces being in contact with oil. By means of computer simulation method values of clearance between cooperating elements as well as ranges of parameters of correct and incorrect operation of hydraulic components have been determined. In this paper results of computer simulation of some experimentally tested hydraulic components such as axial piston pump and proportional spool valve, are presented. The computer simulation results were compared with the experimental ones and high conformity was obtained.

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Samorodov, Vadym, Grigorii Avrunin, and Dmitrii Harmash. "ANALYSIS OF UNIVERSAL CHARACTERISTICS OF HYDRAULIC FLUID POWER TRANSMISSIONS OPERATING IN A COMPOSITION OF HYDRAULIC-MECHANICAL TRANSMISSIONS FOR DIFFERENT WORKING VOLUMES OF HYDRAULIC MACHINES OF AXIAL PISTON TYPE." Bulletin of the National Technical University «KhPI». Series: Automobile and Tractor Construction, no. 2 (December 3, 2020): 11–18. http://dx.doi.org/10.20998/2078-6840.2020.2.02.

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Breidi, Farid, Jordan Garrity, and John Lumkes. "Design and Testing of Novel Hydraulic Pump/Motors to Improve the Efficiency of Agricultural Equipment." Transactions of the ASABE 60, no. 6 (2017): 1809–17. http://dx.doi.org/10.13031/trans.11557.

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Abstract. Hydraulic systems are prevalent in agricultural machinery and equipment and can be found transmitting power for vehicle drive wheels, powering attachments, and controlling motion (booms, steering, load height, etc.). Agricultural applications of fluid power have advanced in terms of capability and efficiency, but opportunities remain for significant improvements in efficiency, noise reduction, and reliability. The average system-level hydraulic efficiency of current mobile agricultural machines is only 21.1%. Because nearly all hydraulic systems use pumps to convert engine power to fluid power, improving the efficiency of the pumps (and motors when used as actuators) significantly impacts the system efficiency. This work examines the impact of using more efficient digital pump/motors to improve the overall efficiency of agricultural equipment, such as tractors, harvesters, planters, fertilizers, sprayers, and attachments. Maintaining higher pump/motor efficiency throughout the operating range is the central principal for the energy savings. Currently used variable-displacement pumps have low efficiencies at low displacement levels due to constant losses that do not scale with the power produced. Digital pump/motors minimize these inefficiencies because energy losses scale more closely with the power produced. Experimental results indicate an average efficiency of 85% when operating at 20% to 100% displacement. This efficiency is 15% to 20% higher on average than with current variable-displacement axial piston pumps. This study demonstrates that achieving this improvement in the efficiency of the pump/motors used in tractors and harvesters alone would conservatively save $61.7 million worth of energy annually for end users in the U.S. agricultural sector. Keywords: Agricultural equipment, Digital hydraulics, Efficiency improvement, Hydraulic pump/motor.

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Zheglova, V., Yu Khomiak, S. Medvedev, and I. Nikolenko. "Numerical and Analytical Evaluation of Service Life of the Details of Axial Piston Hydraulic Machines with Complicated Configuration under Cyclic Loading." Procedia Engineering 176 (2017): 557–66. http://dx.doi.org/10.1016/j.proeng.2017.02.298.

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Stazhkov, S., A. Kuzmin, V. Elchinskiy, and N. Yakovenko. "Tribological tests of the improved piston mechanism of the axial piston hydraulic machine." IOP Conference Series: Materials Science and Engineering 966 (November 14, 2020): 012120. http://dx.doi.org/10.1088/1757-899x/966/1/012120.

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Kibakov, Oleksandr, Yuriy Khomyak, Stanislav Medvedev, Ilya Nikolenko, and Victoria Zheglovа. "Endurance limit of the axial-piston hydraulic machine cylinder block." Diagnostyka 21, no. 1 (January 21, 2020): 71–79. http://dx.doi.org/10.29354/diag/116691.

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Larchikov, Ilya, Andrey Yurov, Sergey Stazhkov, Anastasia Grigorieva, and Alena Protsuk. "Power Analysis of an Axial Piston Hydraulic Machine of Power-intensive Hydraulic Drive System." Procedia Engineering 69 (2014): 512–17. http://dx.doi.org/10.1016/j.proeng.2014.03.020.

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Nikolenko, I. V., Yu M. Khomyak, V. M. Zheglova, O. G. Kibakov, and S. O. Medvedev. "The design of responsible details of an axial piston hydraulic machine improving." IOP Conference Series: Earth and Environmental Science 408 (January 14, 2020): 012006. http://dx.doi.org/10.1088/1755-1315/408/1/012006.

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Fang, Yi, and Masataka Shirakashi. "Mixed Lubrication Characteristics Between the Piston and Cylinder in Hydraulic Piston Pump-Motor." Journal of Tribology 117, no. 1 (January 1, 1995): 80–85. http://dx.doi.org/10.1115/1.2830610.

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This paper presents a method for evaluating the lubrication characteristics between the piston and cylinder in a swash-plate type axial piston pump-motor under mixed lubrication conditions. A numerical analysis is carried out in order to obtain the metal contact force between the piston and cylinder, and the contact ratio λ is shown to represent the mixed lubrication condition both for the pump and the motor strokes. The contact ratio, λ, is also obtained experimentally by detecting electric resistance between the piston and cylinder in a practical swash-plate type machine. The experimental result is expressed by a relationship between λ and SO (the ratio of dynamic pressure to supply pressure) as indicated by the numerical analysis. In conclusion, the mixed lubrication characteristics between the piston and cylinder in a swash-plate type pump-motor is expressed by λ−SO curve irrespective of the operating conditions such as the supply pressure or the rotation speed.

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Jiang, Wanlu, Zhenbao Li, Jingjing Li, Yong Zhu, and Peiyao Zhang. "Study on a Fault Identification Method of the Hydraulic Pump Based on a Combination of Voiceprint Characteristics and Extreme Learning Machine." Processes 7, no. 12 (December 1, 2019): 894. http://dx.doi.org/10.3390/pr7120894.

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Aiming at addressing the problem that the faults in axial piston pumps are complex and difficult to effectively diagnose, an axial piston pump fault diagnosis method that is based on the combination of Mel-frequency cepstrum coefficients (MFCC) and the extreme learning machine (ELM) is proposed. Firstly, a sound sensor is used to realize contactless sound signal acquisition of the axial piston pump. The wavelet packet default threshold denoises the original acquired sound signals. Afterwards, windowing and framing are added to the de-noised sound signals. The MFCC voiceprint characteristics of the processed sound signals are extracted. The voiceprint characteristics are divided into a training sample set and test sample set. ELM models with different numbers of neurons in the hidden layers are established for training and testing. The relationship between the number of neurons in the hidden layer and the recognition accuracy rate is obtained. The ELM model with the optimal number of hidden layer neurons is established and trained with the training sample set. The trained ELM model is applied to the test sample set for fault diagnosis. The fault diagnosis results are obtained. The fault diagnosis results of the ELM model are compared with those of the back propagation (BP) neural network and the support vector machine. The results show that the fault diagnosis method that is proposed in this paper has a higher recognition accuracy rate, shorter training and diagnosis times, and better application prospect.

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Miao, Yang, Yuncheng Jiang, Jinfeng Huang, Xiaojun Zhang, and Lei Han. "Application of Fault Diagnosis of Seawater Hydraulic Pump Based on Transfer Learning." Shock and Vibration 2020 (December 10, 2020): 1–8. http://dx.doi.org/10.1155/2020/9630986.

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The working environment of seawater axial piston hydraulic pump is harsh, and it is difficult to diagnose due to insufficient fault database. In contrast, pumps of the same type but using hydraulic oil have an adequate fault database and are easy to diagnose. In view of the above situation, a fault diagnosis method of seawater hydraulic piston pump based on transfer learning is proposed. The method decomposes the original sampled fault signal by complementary ensemble empirical mode decomposition (CEEMD) to obtain the intrinsic mode function (IMF) that can characterize the original signal. The singular value decomposition (SVD) is performed on the IMF. Then, the obtained singular value is used as a feature parameter to construct a feature vector. The feature data of seawater hydraulic pump and oil pump are used as target data and auxiliary data to form training data. The training data is trained based on the iterative adjustment of the weight through the TrAdaBoost transfer learning algorithm. Finally, the results of diagnosis and classification are compared with traditional machine learning. When the number of training data is 5 groups, the accuracy of transfer learning is 30.5% higher than that of traditional machine learning. The results show that transfer learning has great advantages in the case of a small number of samples.

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Zemnukhov, V. T., A. E. Dreval, and A. S. Vinogradov. "The Hole Reaming Features in Hydraulics Parts." Mechanical Engineering and Computer Science, no. 9 (November 4, 2017): 1–11. http://dx.doi.org/10.24108/0917.0001304.

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The article deals with making high-precision holes in the piston-cylinder pair of the cylinder block of axial piston pumps. These holes must meet high process requirements for accuracy, roughness and absence of apparent porosity, risks and other defects on the machined surface. The sequential analysis of technological operations and transitions in making holes allowed us to determine the causes of defects some of which were eliminated while lapping. To eliminate the other ones, additional machining is performed, i.e. a larger diameter tool re-reaming. It is found that some defects (apparent porosity and circumferential scratch marks) on the machined surface arise from the pores and solid inclusions available in the material of the bronze bushings, and the main part of the defects is formed in the final operation, so-called "reverse reaming". The article examines how the reamer design components influence on defects emergency, experimentally defines an optimum width of the reamer lands, and justifies the need for tool retention. A floating chuck was developed and used in the process. The abovementioned measures allowed us to stabilize the hole-making process and reduce the additional machining to eliminate defects by 22%.

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Li, Zhenbao, Wanlu Jiang, Sheng Zhang, Yu Sun, and Shuqing Zhang. "A Hydraulic Pump Fault Diagnosis Method Based on the Modified Ensemble Empirical Mode Decomposition and Wavelet Kernel Extreme Learning Machine Methods." Sensors 21, no. 8 (April 7, 2021): 2599. http://dx.doi.org/10.3390/s21082599.

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To address the problem that the faults in axial piston pumps are complex and difficult to effectively diagnose, an integrated hydraulic pump fault diagnosis method based on the modified ensemble empirical mode decomposition (MEEMD), autoregressive (AR) spectrum energy, and wavelet kernel extreme learning machine (WKELM) methods is presented in this paper. First, the non-linear and non-stationary hydraulic pump vibration signals are decomposed into several intrinsic mode function (IMF) components by the MEEMD method. Next, AR spectrum analysis is performed for each IMF component, in order to extract the AR spectrum energy of each component as fault characteristics. Then, a hydraulic pump fault diagnosis model based on WKELM is built, in order to extract the features and diagnose faults of hydraulic pump vibration signals, for which the recognition accuracy reached 100%. Finally, the fault diagnosis effect of the hydraulic pump fault diagnosis method proposed in this paper is compared with BP neural network, support vector machine (SVM), and extreme learning machine (ELM) methods. The hydraulic pump fault diagnosis method presented in this paper can diagnose faults of single slipper wear, single slipper loosing and center spring wear type with 100% accuracy, and the fault diagnosis time is only 0.002 s. The results demonstrate that the integrated hydraulic pump fault diagnosis method based on MEEMD, AR spectrum, and WKELM methods has higher fault recognition accuracy and faster speed than existing alternatives.

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Manring, N. D. "The Torque on the Input Shaft of an Axial-Piston Swash-Plate Type Hydrostatic Pump." Journal of Dynamic Systems, Measurement, and Control 120, no. 1 (March 1, 1998): 57–62. http://dx.doi.org/10.1115/1.2801322.

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Traditionally, the theoretical torque on the input shaft of a hydrostatic pump has been determined using a macroscopic “power-in, power-out” approach that neglects the time-varying aspects of this quantity and the compressibility of the hydraulic fluid within the circuit. In contrast to the traditional approach, this research analyzes and sums the basic forces within the machine to compute the instantaneous torque exerted on the shaft. It is shown that the instantaneous torque repeatedly varies by 1.5 percent of its maximum value and that resonant frequencies of the pump occur at even multiples of the “piston-pass” frequency. Furthermore, an integral average of the instantaneous torque is performed and shown to deviate by a maximum of 3 percent from the traditional method of computing this quantity.

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Casoli, Paolo, Mirko Pastori, Fabio Scolari, and Massimo Rundo. "Active Pressure Ripple Control in Axial Piston Pumps through High-Frequency Swash Plate Oscillations—A Theoretical Analysis." Energies 12, no. 7 (April 10, 2019): 1377. http://dx.doi.org/10.3390/en12071377.

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Pressure ripple has always been a major drawback in hydraulic circuits, since it is the main source of the overall noise emitted by the pump. This article presents a theoretical analysis on the active control of the pressure ripple in an axial piston pump by properly moving the swash plate. The reduction of the pressure oscillations is studied in an active way and for this purpose a mathematical model of the whole pump has been developed, focusing on both the fluid dynamic aspects and the component dynamics. An experimental activity has been performed in order to validate the pump mathematical model. The results of the simulation, compared with the experimental data, highlight a suitable capability of the model to predict both the dynamics of the swash plate and the delivery pressure ripple. The validated model has been used for implementing an active control of the pressure ripple with the aim of properly modifying the machine displacement at high frequency in order to vary the instantaneous delivery flow rate and, consequently, the outlet pressure. The control strategy is grounded on moving the swash plate for modifying the motion law of the pistons through a servo valve integrated into the displacement control system. The simulations results have demonstrated that acting on the pump displacement control is possible to considerably reduce the amplitude of the pressure oscillations.

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Manring, Noah D. "Designing the Shaft Diameter for Acceptable Levels of Stress Within an Axial-Piston Swash-Plate Type Hydrostatic Pump." Journal of Mechanical Design 122, no. 4 (July 1, 1999): 553–59. http://dx.doi.org/10.1115/1.1313827.

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In this research, the diameter of the shaft within an axial-piston swash-plate type hydrostatic pump is considered from a stress point of view. To analyze the loading of the shaft, the components within the pump are studied using a force and torque diagram and it is shown that the loads are applied differently for three main sections of the shaft. From the force and torque diagram, the actual shaft loads are determined based upon the geometry of the pump and the working pressure of the hydraulic system. Using well-accepted machine design practices, governing equations for the shaft diameter are produced for the various regions of loading along the shaft. These equations consider both bending and torsional stresses on the outer surface of the shaft. Results for the required shaft diameter are then computed for a typical pump design and compared to the geometry of an actual shaft. It is noted that stress concentrations can significantly alter these results and that the required shaft diameter can be reduced by applying the proper heat treatments and increasing the shaft strength. Finally, the designer is cautioned regarding the deflection difficulties that can arise when the shaft diameter is reduced too much. [S1050-0472(00)01704-9]

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Kou, Baofu, Zhenshun Li, Zhang Zhang, and Ruiqing Li. "Tribological Properties of ZrO2 Coating on the Ball Joint of an Axial Piston Pump in High Water-Based Emulsion Medium." Mathematical Problems in Engineering 2021 (April 29, 2021): 1–16. http://dx.doi.org/10.1155/2021/9978006.

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This paper studies the tribological properties of the ZrO2-coated spherical joint pair of the axial piston pump in a high water-based emulsion medium. Firstly, atmospheric plasma spraying was used to prepare the ZrO2 coating on the surface of the spherical joint pair. Secondly, the tribological characteristics of the steel-steel pair and ceramic-ceramic pair were analyzed by the friction and wear testing machine under the conditions of a high water-based emulsion concentration, load size, and load frequency. White light interference three-dimensional surface profiler and scanning electron microscope were used to analyze the original and worn surfaces of the samples, and then the friction and wear of the different material pairs were discussed. The results show that the friction reduction and wear resistance of the ceramic ball joint are superior to those of the steel ball joint. When the load is 100 N, the frequency is 1 Hz, and the emulsion concentration is 5%, and the friction coefficient and wear loss of the ceramic-ceramic ball joint pair are the lowest. The emulsion concentration and load have great influence on the friction coefficient and wear amount, while the frequency has little influence on them. With increasing concentration of the emulsion, the friction coefficient decreases and tends to be stable, but with increasing of load, the friction coefficient and wear increase. The friction coefficient and wear loss of the ceramic-ceramic ball joint in pure water are 0.25 times higher than those of the steel ball joint under the same working conditions. Therefore, when the concentration of the high water-based emulsion is 5%, 100 N load, 1 Hz frequency, the ceramic-ceramic ball joints display the best friction and wear resistance of the two. The research results provide a theoretical basis for the design, manufacture, and application of the ceramic coating hydraulic components in a high water-based emulsion medium.

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Nikolenko, Ilya, and Andrey Ryzhakov. "6 Modelling of Operational Cycle in a Hydraulic Drive Based on Adjustable Axial Piston Hydraulic Machines." Science and Education of the Bauman MSTU 15, no. 09 (December 3, 2014). http://dx.doi.org/10.7463/0915.0812337.

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Schenk, Andrew, and Monika Ivantysynova. "A Transient Thermoelastohydrodynamic Lubrication Model for the Slipper/Swashplate in Axial Piston Machines." Journal of Tribology 137, no. 3 (July 1, 2015). http://dx.doi.org/10.1115/1.4029674.

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A transient lubrication model has been developed for the sliding interface between the slipper and swashplate in axial piston hydraulic pumps and motors. The model considers a nonisothermal fluid model, microdynamic motion of the slipper, as well as pressure and thermal deformations of the bounding solid bodies through a partitioned solution scheme. The separate contributions of elastohydrostatic and elastohydrodynamic lubrication are studied. Although hydrostatic deformation dominates, hydrodynamic effects are crucial for actual operation. Finally, the impact of transient deformation on lubricant pressure is explored, with its consideration necessary for accurate analysis.

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Ernst, Meike, Monika Ivantysynova, and Andrea Vacca. "Shaping the Piston–Cylinder Interfaces of Axial Piston Machines for Running in the High-Pressure Regime with Water as the Hydraulic Fluid." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, January 17, 2022, 095440622110686. http://dx.doi.org/10.1177/09544062211068643.

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Water’s low viscosity renders it a poor lubricant, but its green footprint, non-toxicity, inflammability, and low cost make it a desirable hydraulic fluid. Axial piston machines running on water are commercially available, but, especially the larger units, do not operate in the high-pressure regime ( ≥300 bar). The present work investigates micro surface shaping as a design solution for the critical piston–cylinder interfaces of these units, which are particularly hard-struck by the low viscosity of water in that the pistons are subject to a heavy side load, and these interfaces cannot be hydrostatically balanced. Through virtual prototyping, the effect of two surface shapes at a high-pressure operating condition is studied for the case of a 75 cc commercial unit: first, the concave bore profile, which gives the bore surfaces through which the pistons travel the lengthwise cross-section of a circular arc, and second, the barrel piston profile, which bestows this cross-section on the piston running surface instead. The design studies conducted show that, on account of the manner in which the pistons of these machines deform over the high-pressure stroke, the concave bore profile is most able to improve overall load support when its apex is in the middle of the guide length, or shifted toward the displacement chamber. Furthermore, the concave bore profile outperforms the barrel piston profile, largely because when the piston’s axial movement takes its apex into the displacement chamber, this surface shape is no longer able to enhance the piston-bore surface conformity at the end of the interface bordering the displacement chamber that is conducive to hydrodynamic pressure buildup in that region.

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Manring, Noah D., and Viral S. Mehta. "Physical Limitations for the Bandwidth Frequency of a Pressure Controlled, Axial-Piston Pump." Journal of Dynamic Systems, Measurement, and Control 133, no. 6 (September 29, 2011). http://dx.doi.org/10.1115/1.4004056.

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The objectives of this paper are to identify the design parameters that have the greatest impact on the bandwidth frequency of a pressure controlled, axial-piston pump. This study is motivated by the fact that a physical limitation for these machines has been observed in practice, as it has been difficult to increase the bandwidth frequency much beyond 25 Hz. Though much research has been done over the past thirty years to understand the dynamical behavior of these machines, the essential design-characteristics that determine the bandwidth frequency of the pump remain elusive. In part, this is due to the fact that the machine is complex and when coupled with a hydraulic control valve that is disturbed by steady and transient fluid-momentum effects this dynamical property becomes difficult to assess. In order to achieve the objectives of this research, this paper presents the most comprehensive pump-and-valve model of a pressure controlled, axial-piston machine available in the literature to date. The pump model includes the effects of the discrete pumping-elements acting on the swash plate, while the valve model includes both steady and transient fluid-momentum forces. To identify the dominate features of the model, nondimensional analysis is employed and the complexity of the model is subsequently reduced by eliminating negligible terms. Furthermore, a closed-form expression for the bandwidth frequency is employed and perturbation analysis is used to identify the dominant set of parameters that impact the bandwidth frequency of the pump. In conclusion, it is shown that, by far, the greatest impact on the bandwidth frequency may be achieved by reducing the swept volume of the control actuator and by increasing the flow capacity of the control valve.

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Nwankwojike, Bethrand N., Chukwunonso N. Nwogu, and Godswill Kalu. "Development of a Manually Operated Hydraulic Press and Pull." FUOYE Journal of Engineering and Technology 2, no. 2 (September 30, 2017). http://dx.doi.org/10.46792/fuoyejet.v2i2.111.

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A hydraulic press and pull machine comprising of a frame, cylinder and piston, two threaded studs, hydraulic pump and hose, pulling clamp and a workpiece support was designed, fabricated and evaluated. The machine is manually operated. The maximum shear force, maximum bending moment and maximum displacement of the machine workpiece support were determined as 74.9491N, 16.6335N-m and 4.367e3mm for a simulated load of 1000N. Maximum axial, bending and torsional stresses were also determined as 0.00359, 701998 and 0.00653N/m2 respectively. performance of the developed machine was determined using seven bearings of bore diameters 24, 30, 40, 50, 65, 80 and 100mm respectively, fitted into seven corresponding shafts with shaft deviation of ±0.001mm and dismantled afterwards using three different methods: traditional hammering, the developed manual hydraulic press and pull machine and already existing electrically powered hydraulic press. The results of the experiments showed that traditional hammering is the most time consuming method of mounting and dismounting force fits, followed by the use of the developed press-pull machine while electrically powered hydraulic presses are the fastest.The machine which was fabricated with local materials will reduce the time and stress associated with installation and removal of bearings, and other forms of force fits in machine assemblies. Hence, leading to an overall improvement in the standard of machines/equipment fabricated in Nigeria

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Casoli, Paolo, Federico Campanini, Andrea Bedotti, Mirko Pastori, and Antonio Lettini. "Overall Efficiency Evaluation of a Hydraulic Pump With External Drainage Through Temperature Measurements." Journal of Dynamic Systems, Measurement, and Control 140, no. 8 (March 7, 2018). http://dx.doi.org/10.1115/1.4039084.

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In the recent years, industries have been working on the online condition monitoring of systems and components in order to definitely abandon the time-based maintenance and switch efficiently to a condition-based maintenance. Therefore, the research field related to prognostics and health management (PHM) has been gaining more and more importance. In the field of hydraulic pumps and motors, the overall efficiency is an important parameter to monitor and the thermodynamic method has historically been proposed for the online evaluation of this parameter for hydraulic machines without external drainage. Indeed, for this kind of machines, the thermodynamic method allows the evaluation of the overall efficiency by measuring only the temperatures and the pressures at the suction and the delivery ports, thus avoiding the use of cumbersome and expensive sensors, such as flow meters and torque sensors. This paper investigates the use of the thermodynamic method for hydraulic machines with external drainage. The case study of a swash-plate type axial-piston pump is considered. In this first part of the project, the objective was to validate the proposed thermodynamic method by comparing its results with the ones obtained through the mechanical, therefore an extensive experimental activity was carried out and two flow meters were used to measure the drainage and the delivery flow rates. The pump was tested in different operating conditions and the uncertainty related to the overall efficiency was calculated accurately in order to compare the two approaches properly.

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Keller, Nathan, Annalisa Sciancalepore, and Andrea Vacca. "Demonstrating a Condition Monitoring Process for Axial Piston Pumps with Damaged Valve Plates." International Journal of Fluid Power, February 22, 2022. http://dx.doi.org/10.13052/ijfp1439-9776.2324.

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Unexpected pump failures in mobile fluid power systems result in monetary and productivity losses, but these failures can be alleviated by implementing a condition monitoring system. This research aims to find the best condition monitoring (CM) technique for a pump with the fewest number of sensors, to accurately detect a defective condition. The sensors choice in a CM system is a critical decision, and a high number of sensors may result in disadvantages besides additional cost, such as overfitting the CM model and increased maintenance. A variable displacement axial piston pump is used as a reference machine for testing the CM technique. Several valve plates with various magnitudes of quantifiable wear and damage are used to compare “healthy” and “unhealthy” hydraulic pumps. The pump parameters are measured on a stationary test rig. This involves observing and detecting differences in pump performance between the healthy and unhealthy conditions and reducing the number of sensors required to monitor a pump’s condition. Observable differences in drain flow were shown, and machine learning algorithms were able to successfully classify a faulty and healthy pump with accuracies nearing 100%. The number of sensors was reduced by implementing a feature selection process and resulted in only five of the 23 sensors to correctly detect pump failure. These sensors measure outlet pressure, inlet pressure, drain pressure, pump speed, and pump displacement. The resulting reduction of sensors is reasonably affordable and relatively easy to implement on mobile applications.

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Journal articles on the topic 'Axial-piston hydraulic machines'

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