Dissertations / Theses on the topic 'Cycloidal gear'

The RV reducer (one tpye of cycloid reducer) which has two stage transmissions is widely used in manyfields of engineering. This project is going to design the first stage of the RV reducer, as well as therelated components. The details contain design of input shaft, planetary gears, output shaft, generalbearings and eccentric bearings. The fatigue analysis is mostly used in the calculation process becausethe fatigue failure happens frequently in such rotation machine. In the same time, the general bearingsdesign is based on SKF General Catalogue and the eccentric bearings design is supported by theChinese standard.

碩士
吳鳳科技大學
光機電暨材料研究所
105
The purpose of this thesis is about the calculation and size of the components of the cycloid in the reducer and to employ the resultant reducer into the production with the hope that it would fill another part of the market. The authors are interested in providing transmission for robust systems and various industrial purposes which requires a large proportion of reducer. Provided with the necessary input data, the model also runs a further analysis of the true recirculation reducer. In order to obtain the size and shape of the gears, some of the work of Professor Ognyan Alipiev has been used. Professor Alipiev is the Angel Kunchev at Institutional and Machine Theory Department, Lucas University, Bulgaria. In order to determine the force on components, models and drawings have been used through Solidworks (SW) CAD software and SW simulation environment. One can design by using the Resulant the process of calculation and determine both the geometrical shape and performance of the cycloidal reducer.

碩士
國立臺灣大學
機械工程學研究所
100
Cycloidal gear reducers are commonly used for speed reduction where machine needs high reducing ratio and/or high torque drive. In the past decades, a great amount of research has been focused on the design of cycloidal gear reducers and many patents were also invented. Nonetheless, not much research has addressed the topological structure of the cycloidal gear reducers. In the first part of this thesis, the topology of the cycloidal gear reducer is analyzed first. Then structural characteristics of such mechanisms are investigated and summarized. Subsequently, a methodology for synthesizing new cycloidal gear reducer is proposed and new mechanisms are enumerated. In the second part of the thesis, the dynamic analysis of the reducer is conducted via Newton’s law and linear elasticity. Finally, the efficiency of reducer is studied when taking the inertia effect into account. The result shows that the cycloidal gear reducer is able to remain high torque when the mechanical energy varies.

碩士
國立臺灣科技大學
機械工程系
107
At present, the common manufacturing method of cycloidal gears seen on the market is grinding after hobbing. The extrusion processing of cycloidal gears is a new research field. Although the manufacturing time is relatively short, it also has the disadvantage of difficult to control the size and accuracy, which has caused many troubles to the actual production. To solve the problem of the precision of extruded products, many people will use analysis software to simulate and analyze the situation of products after processing, and then amend it to reduce waste generation. But after simulation, the output drawings of the products show irregular triangular mesh, which makes the surveyors not know how to start. At present, there is no complete measurement method for this aspect. So this paper proposes DEFORM 3D triangular mesh tooth profile error evaluation and compensation to improve this situation. This paper first established several mathematical models, the cycloid gear and do the physical move, modification way equation is expressed. Then, with the help of these mathematical models, this paper will explain in detail how to use DEFORM 3D triangular mesh to evaluate and compensate tooth profile errors after extruding gear samples with simulated Workpiece, extract data points on a single cross-section from the samples and calculate their errors with theoretical values, so as to benefit further. The compensation of the left and right tooth surfaces of the lower die is calculated by the sensitivity matrix, and then the compensation correction is carried out subsequently. After that, a new cold extrusion simulation analysis process was established, especially the improved design of the lower and middle die of the extrusion die was more suitable for actual production and manufacturing. To verify the feasibility of the gear measurement and compensation method proposed in this paper, the details of the process setting and the experimental results will also be fully introduced in this paper.

碩士
國立虎尾科技大學
機械與機電工程研究所
102
The cycloidal gear is widely used in many industrial application for speed and torque transmission purposes because the advantages of high efficiency, large ratios, compact design, long and reliable working life. A fine design about the geometry of the output shaft will decrease the stress concentration on the gear disc when transferring power. In this study, a computer program is developed for calculating the profile data of the cycloidal gear and export to Pro/E software to create a 3D cycloid mechanism module for dynamic analysis. The dynamic models considering friction, gear clearance and time-varying stiffness were established. The ANSYS/LS-DYNA is utilized to analyze the dynamic responses of gear transmission, surface contact stresses, root bending stresses, and contact stress of the output shaft of a cycloidal mechanism. The stiffness and elastic deformation of gear teeth are calculated by using the finite element method with actual geometry and positions of the gears. The modified suggestion of the geometry of the output shaft will be carry out by the results of dynamic simulation.

碩士
國立虎尾科技大學
機械設計工程系碩士班
107
The process of the cycloidal gear movement is driven by point contact, Therefore, if the tooth shape is poorly designed, the tooth surface of the cycloidal gear will be uneven during operation. The tooth surface wear is different and the transmission accuracy and service life are reduced. In order to make the tooth surface force close to uniform size. In this paper, the tooth surface is evenly stressed, Minimum tooth surface stress and Minimum tooth surface maximum stress wave front difference is the target. Use optimization analysis to achieve the above conditions and find the best parameter values from the process of optimization analysis. The main factors controlling the tooth profile of the cycloidal gear are two parameters of equidistant shape modification and distance modification. Write a toothed program by programming the software to control the two factors of equidistant shaping and shifting, Calculate the cycloidal gear parameters, To facilitate the shaping of the tooth profile, Optimized experimental planning with Design-Expert optimized software, Tooth shape control according to the equidistant shape modification and the distance correction parameter value obtained in the plan, And calculate the tooth shape and import it into the 3D software to build the three-dimensional model of the tooth profile and the three-dimensional model of the components of the planet carrier, the pin wheel and the eccentric shaft, And organize them. To simulate the position of the RV reducer, The constructed 3D assembly model is then imported into the HyperMesh preprocessor for finite element model partitioning, material property setting, coordinate system setting, initial condition setting, contact mode setting, constraint condition setting and output condition setting. Finally, the finite element analysis software LS-Dyna is used to calculate the tooth surface force. A total of 4 sets of experiments verifying the CAE analysis model were performed with subsequent tooth profile comparison with an accuracy of 97.8%. Finally, the optimized tooth profile has a maximum stress of 193.064 MPa at a distance of -0.005 mm and an equidistant 0.0047 mm. The tooth profile is used to regulate the maximum tooth stress of the Nabtesco RV-27C tooth profile to 188.09MPa. The accuracy between the two is 97.4%.

碩士
國立臺灣大學
機械工程學研究所
101
Cycloidal reducers have been applied for the transmission mechanism in precision machine for a long time. Recently, the development of cycloid gear reducers has been focused on the high torque density design. In light of this trend, it is necessary to understand and explore the gear reducer in the force/torque aspect. This thesis first reviewed the methods of force analysis for cycloid gear reducers. Then, a method based upon the superposition method is proposed for the analysis of the contact force between cycloid lobe and pin. The results are compared with the results of FEM analysis as well as traditional force analysis method. This paper also presents the detail simulation process using the FEM software. The process shows that convergent results can be achieved by using the parameters selected in the thesis.

碩士
清雲科技大學
機械工程研究所
95
In this study, the mathematical models cycloidal gears are derived based on the theorem of gearing firstly. Then, the meshing model of cycloidal gear pair is set up and tooth contact analysis (TCA) is adopted to investigate the transmission errors with different design parameters and assembly conditions. Furthermore, the general-purpose FEA software, ABAQUS, was applied to evaluate the formation of bearing contacts and stress distribution on the tooth surfaces according to different design parameters. Results in this study not only verify the contact nature of cycloidal gear pairs, but also provide the bases for upcoming research on cycloidal gear pairs such as curvature analysis and sliding ratios.

碩士
國立臺灣科技大學
機械工程系
107
As factory production gradually evolves toward automation, robotic arm replacement is the current trend. Because the mechanical arm joint output is large, it is necessary to use a small volume and high-speed ratio precision reducer to increase the torque. Therefore, cycloidal gears with high gear ratio, small size, lightweight and low noise are often used in robot arms. The purpose of this paper is to develop the accuracy evaluation method of cycloidal gear and propose a mathematical model for accuracy evaluation. Firstly, the 2D point data of the tooth profile are imported, and all the measurement points are center-corrected by the conjugate gradient method, advance and retreat method and the golden section method in the one-dimensional search method. After that, using the B-spline curve fitting method to fit the measurement points, to ensure the fitting curve, the fitting error will be further calculated. After confirming the condition of the fitting error, the pitch radius is used to find the pitch points of the left and right tooth. The content of the evaluation of cycloidal gear in this paper is mainly divided into two parts. The first part is the evaluation of pitch error. The pitch error of the cycloidal gear can be evaluated using the found pitch points and the calculations defined by DIN. There are three calculation items for the pitch error evaluation according to DIN 3960[19], including single pitch error, accumulated pitch error, and run out. After calculating these pitch errors, the database can be further used to make a database using the evaluation level compiled by DIN3962 [20], and the database can be used to judge the accuracy level of the pitch errors. The second part is the calculation of the tooth profile and tooth thickness error. Before calculating the tooth shape error, the theoretical tooth profile and the pitch point of the fitting tooth profile must be coincident, and then the error of the fitting point and the corresponding theoretical point are calculated. The tooth thickness is subtracted from the fitted profile and theoretical one. Using the established method to evaluate the accuracy of commercially available products can be used as a basis for determining the manufacturing tolerance of cycloidal gears.

碩士
國立雲林科技大學
機械工程系
102
Cycloid reducer have many uses in industry, and is compact structure and with high efficiency speed reducer. Until now, for the study of cycloid reducer is to research its unique tooth profile. The formation of tooth profile have several ways, but for how to design a different gear ratio is not systematic design approach on cycloid reducer. This paper is proposed design method for different gear ratio of speed reducer and hope the backlash well minimum when speed reducer is rotation without interfering. For how to make the backlash to reduce method is adjusting the main parameters affecting the gear backlash to observe its changes, the most important that influence cycloid reducer have four factors. First, the arc radius of the ring gear, second, the distance from arc center of the ring gear to center of the ring gear, third, the arc radius of the cycloid gear, fourth, the distance form smaller arc center of the cycloid speed to center of the cycloid gear. By adjusting the size of the four factors to find the design parameters and make the backlash well minimum when speed reducer is rotation, and applied in gear ratio of 1:3, 1:5, 1:10, 1:15 speed reducer. Finally, using computer to design the CAD model and dynamic simulation software to simulate the movement of the situation, verify the accuracy of the size design.

碩士
國立虎尾科技大學
動力機械工程系機械與機電工程碩士班
105
In the industry, cycloid reducer gradually received more attention, due to it has a large transmission ratio, small size, light weight, high efficiency, smooth operation, and long service life. Cycloid gear is the most important part of cycloid reducer, because the tooth profile of the cycloid gear will affect the force and transmission accuracy. Therefore, the tooth profile of the cycloid gear needs to be studied deeply in order to improve the cycloid reducer efficiency. This study describes principle of forming the cycloidal profile and three different kinds of profile modification method. Five kinds of modification combination are selected for the analysis. The models of cycloid gear are set up by SolidWorks and Mathematica, then, the meshing and boundary conditions are defined in HyperMesh. The maximum von-Mises stresses and kinematic errors are obtained through LS-DYNA. Compare different kinds of modification combination, the best kind of tooth profile modification combination is obtained.

博士
國立中正大學
機械工程所
98
Of the gear pairs and transmissions that play an important role in many industrial applications—including vehicles and machine and power tools—involute helical gears are among the most common because of their simple geometry, easy manufacturing, and low sensitivity to center distance. However, the conventional helical gear pair meshes in line contact, is very sensitive to assembly errors, and is prone to edge contact problems. Therefore, based on the theory of gearing and differential geometry, this investigation proposes a novel face-hobbing method to generate a helical gear with lengthwise crowning. In this method, two head cutters form an imaginary generating rack with lengthwise cycloidal tooth traces that generate cylindrical helical or spur gears with longitudinal cycloidal traces. The proposed cutting method, in which the cutter blade travels longitudinally from one side face to the other to create smoother longitudinal cutting marks, is particularly efficient for continuous indexing cutting. In gear generation, this method relies on the ratio between the cutter rotation speed and the generating roll speed. When the head cutters move from the left start-of-generation position to the right end-of-generation position, tooth flank generation is complete. In addition, because the cutting marks in this proposed method are perpendicular to the contact path between the mating gears, the height of the cutting mark can be reduced by decreasing the rolling ratio of the cutter rotation speed to the generating roll speed. In addition, this mathematical model of a cutting system can simulate three different modules. First, the procedure uses all inside cutter blades mounted on the head cutter and all outside cutter blades for a double-concave gear. Because all inside and outside cutter blades are mounted on the same head cutter, it is easy to simulate a cutting system for a convex-concave helical gear using one head cutter. The three possible contact arrangements between the racks’ meshing tooth traces depend on the arrangement of each head cutter, whether convex to convex, convex to straight, or convex to concave. It should also be noted that the contact load capacity of the proposed longitudinal cycloidal gear drive is larger than that of an involute gear drive. Drawing on a dual face-hobbing method, we develop a mathematical model with lengthwise crowning and analyze the tooth undercutting and sensitivity of the tooth contact pattern using the techniques proposed by Litvin. Applying the mathematical model of tooth contact analysis also allows evaluation of meshing and contact characteristics without load when assembly errors and axes misalignment can occur. Because the proposed helical gear has longitudinal cycloidal traces, the gear pair meshes in point contact, a condition that not only eliminates tooth edge contact but decreases the gear vibration and noise from axial misalignment and increases the bearing strength of the contact gears.

碩士
國立雲林科技大學
機械工程系
106
RV reducer plays an important role in industrial robot. RV reducer is a kind of two-stage cycloid reducer; the first stage is composed of basic gear and the second stage is composed of cycloid reducer. Cycloid drive has high reduction ratio, small axial thickness high efficiency and low backlash. By combining basic gear and cycloid reducer makes RV reducer more functional and broaden the application scope. Therefore, my subject of this master thesis focuses on studying and analyzing the inner construction and basic character. I use creative mechanism design to analyze and combine the three-bar and four-bar mechanism and the cycloidal gear mechanism to make 38 different models. I also choose 603-1 model to do gear design and torque calculation; besides, I use CAD to draw 3D model and put the model into finite element analysis software and analyze the stress division of the mechanism. At the end of testing, 603-1 model is chosen to put into reality and allowed to manufacture the finished product. After using the fledgling production to measure rotating speed and torque, the measurement results is found that the torque measurement error caused by the dimensional processing error and the measurement platform vibration is 11.66%; then the tachometer reading to the decimal point first speed measurement error is 1.5%. From above all, we know that the measurement matches thesis so the comparison of RV reducer’s functions can clearly explain the character of new-model reducer. The last but not the least, the result of this study can help combine and design the cycloid drive and integrated planetary and ascend the application scope of reducer and simply the inner structure.

碩士
國立宜蘭大學
機械與機電工程學系碩士班
101
Gear pump has been widely used in industries such as the petrochemical industry, food industry, paper industry, and biomedical and so on. It matures manufacturing technology. The developments of gear pump are focus on involutes gears but opening line gear. Only a few opening line gears apply to internal-gear pumps and seldom are used of external-gear. This study derivates the function of transmitted volume, analysis the transmitted torque, fabricates the gear pump, and testes its property. In this investigation, mathematical formula and transmitted volume formula of the gear can be derivative by the basic principles of the gear meshing, rack cutter, and gear mechanism by rotating the coordinate plane. Comparing the different rolling of transmitted volume with opening line gear can find the less gear tooth for the steady transmission. Rotor tooth of gear pump is chosen from contact ratio of rounding and pitch circle more than one. Using the Solid Works Flow simulation to analysis the transmitted torque between the same tooth shape but different amount and the same amount tooth but different tooth shape in different pressure. Compositing the gear pumps parts fabricated by CNC engraving and milling machine and comparing the data with simulation, it can find that the mechanical conversion efficiency is around 63％ to 72％. Mechanical conversion efficiency of gear pump on market is about 70％.Results of this study are for reference in internal- opening line gear pumps and could be use in micro gear pumps.

碩士
國立臺灣海洋大學
輪機工程學系
102
This paper builds optimal parameters for the fine hydro-mechanical blanking. In this approach, the wear problem of V-ring could be avoided. The ejector force of traditional fine blanking can be replaced by back pressure of the hydro liquid. It can decrease the phenomenon of roll-over. Taguchi experimental method is used to investigate the relations between these parameters and the burning length; these parameters are the back pressure, the flow pressure in U-type of cavity, the width and high of U-type of cavity and the holding force. The cycloid gear used for experimental test is adopted owing to the need of industry for the precise size. The result shows the optimal burning surface can reach 92% of high of the work-piece and the solution obtained from FEM also has the same result. It is shown that this approach can fulfill the more complex shape of blanking.

碩士
國立中央大學
機械工程學系
105
Cycloid planetary gear drives have many advantages in comparison of the conventional involute planetary gear drives, such as high gear ratio, good performances in sharing the transmitted load, and shock absorbing ability. Although modern FEM software offer good solving possibility, it is not efficient to simulate the contact stress and the corresponding contact pattern of the tooth pairs. Especially it will be more expensive in time while designing modified cycloid profile for backlash control by using FEM. The aim of the thesis is to propose an approach to analyze the contact characteristics of the cycloid planetary gear drives with modified flanks, including the transmission errors, backlashes and the loads acting among the contact cycloid-pin tooth-pairs. In the proposed model, the influence of the relevant errors on shared loads and the contact stress are considered. On the other hand, backlash and transmission errors due to the flank modification and errors will be also analyzed in the thesis. The results of this thesis may be summarized as follows: Modification parameters have strong influences to the continuity of transmission, which means it causes vibrations or not during meshing due to the suitability of clearance, and similar situation can be found in results of backlash; Eccentric errors influence the transmission errors much more than manufacturing errors; Modification causes the difference of load sharing factor on the basis of the tooth number shared the load during engaging; All the contact simulation results illustrate a saddle-shaped contact pattern with concentrated stresses on the face-end ; No matter which kind of assembly errors, the values of Loaded Transmission Errors(LTEs) and the max-to-min values are always larger than Transmission Errors(TEs) because the load always causes a leading angle on crankshaft. The above results are summarized the contact results influence by modification and assembly errors, and proposes an aid for analyzing the contact characteristics under loading, which helps designing the cycloid drives with better performance in the future.

碩士
國立中央大學
機械工程學系
106
Because the loads acting on the contact tooth pairs and the cranks of the cycloid planetary gear drives with tooth number difference (abbr. TND) of one are very large, and the contact ratio is reduced with flank modification, the load capicity cannot be enhanced effectively. Therefore the design concept by using TND of two is proposed in the study to give a possibility to improve the loaded contact characteristics. The cycloid disk with TND of two can be regarded as combination of two sam base cycloid profile rotated against each other with an pitch angle. Therefore the analysis model of the cycloid planetary gear reducers with TND of two can be expaned from the model with TND of one. With reguarding odd and even numbered tooth pairs, the gear meshing analysis and the loaded tooth contact analysis (LTCA) model of the cycloid profile with TND of two can be established based on the developed mathematic model and the related analysis models of the cycloid profile with TND of one. The LTCA approach in the study is based on the influence coefficient method with consideration of bearing stiffness. In this parper, the influences of the design parameters, i.e., the pin raidus and the eccentricity, on the loaded contact characterisitcs, such as the flank profile, the contact ratio, the shared loads and the contact stresses. Based on the analysis results, appropriate design parameters are determined for the following analysis: (1) the effect of the bearing stiffness of the loaded tooth contact characteristics, and (2) comparative analysis with the conventional drives with TND of one on the loaded contact charateristics. The results from the influence analysis of parameters show that the cycloid drive with TND of two having smaller pins and a larger eccentricity owns a larger contact ratio and reduced shared loads. The eccentricity affects the variation of the load sharing stronger than the pin radius, not only because of the tooth profile, but also because of the transmission angle. A larger eccentricity can lower the shared load and the contact stress, but smaller pins reduce shared load and increase larger contact stress sightly. The influence of the bearing stiffness, as the results show, causes the contact of the tooth pairs occuring earlier than the condtion without considering the bearing stiffness, because of additional displacements with three degrees of freedom. The maximum load sharing is enlarged because the displacement is closer to the front part of tooth pair due to the transmission angle. Moreover, the variation of the shared load on flank with considersing bearing stiffness performs in cyclic jumping type, but the period duration is reduced as a half due to the change of odd and even numbered tooth pair change. Even so the condition of bearing stiffness is not impact on the bearing load. The comparative analysis results with TND of one show that the maximum sharing load in the case of TND of two can be reduced 35% relative to TND of one, and is distributed more soomthly. On the other hand, the maximum contact stress for TND of two can be enlarged 25% with respect to TND of one. But the contact stress for TND of two still remains at the end of contact, and the contact stress concentration occurs due to the edge effect of the tip corner. Furthmore, the radial bearing load in the case of TND of two can reduce 50% relative to the case of TND of one. But the lowered radial force is still much smaller than the circumferential force. The radial bearing force reduce just 5% relative to TND of one. From the analysis results of this paper, the cycliod planetary gear drives with TND of two can effectively increase the contact ratio and reduce the maximum load sharing and the maximum contact stress. However, it can not efficiently reduce the bearing load on the crankshaft.