scholarly journals Transmission Performance Analysis of RV Reducers Influenced by Profile Modification and Load

2019 ◽  
Vol 9 (19) ◽  
pp. 4099 ◽  
Author(s):  
Hui Wang ◽  
Zhao-Yao Shi ◽  
Bo Yu ◽  
Hang Xu

RV reducers contain multi-tooth contact characteristics, with high-impact resistance and a small backlash, and are widely used in precision transmissions, such as robot joints. The main parameters affecting the transmission performance include torsional stiffness and transmission errors (TEs). However, a cycloid tooth profile modification has a significant influence on the transmission accuracy and torsional stiffness of an RV reducer. It is important to study the multi-tooth contact characteristics caused by modifying the cycloid profile. The contact force is calculated using a single contact stiffness, inevitably affecting the accuracy of the result. Thus, a new multi-tooth contact model and a TE model of an RV reducer are proposed by dividing the contact area into several differential elements. A comparison of the contact force obtained using the finite element method and the test results of an RV reducer prototype validates the proposed models. On this basis, the influence of load on the different modification methods is studied, including a TE, the mechanical performance, and the transmission efficiency. In addition, the proposed reverse profile is particularly suitable for situations with a large clearance and torque. This study provides a reliable theoretical basis for a multi-tooth contact analysis of a cycloid profile modification.

2020 ◽  
Vol 10 (14) ◽  
pp. 4859
Author(s):  
Ting Zhang ◽  
Xuan Li ◽  
Yawen Wang ◽  
Lining Sun

The current load distribution model for cycloid drives based on the Hertz contact stiffness typically assumes a two-dimensional planar problem without considering the tooth longitudinal modification effects, which fails to comply with the practical situation. In this paper, this issue is clarified by developing a semi-analytical load distribution model based on a three-dimensional and linear elastic solution. Unloaded tooth contact analysis is introduced to determine the instantaneous mesh information. The tooth compliance model considering tooth contact deformation is established by combining the Boussinesq force–displacement relationships in elastic half-space with an influence coefficient method. With this, the loads, contact patterns, and loaded transmission error are calculated by enforcing the compatibility and equilibrium conditions. Comparisons to predictions made with the assumption of Hertz contact stiffness are presented to demonstrate the effectiveness of the proposed model, which shows good agreement. At the end, the effect of tooth longitudinal modifications on load distributions is investigated along with various loading conditions. This study yields an in-depth understanding of the multi-tooth contact characteristics of cycloid drives and provides an effective tool for extensive parameter sensitivity analysis and design optimization studies.


2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Xiaoxiao Sun ◽  
Liang Han ◽  
Jian Wang

A new one-stage type cycloid drive reducer named China Bearing Reducer (CBR) is designed and its tooth contact analysis is investigated. First, the CAD model is built in SolidWorks and the structure of CBR reducer is introduced. Its advantages and disadvantages are compared with rotor vector (RV) reducer and harmonic drive reducer. Second, the mathematic model of cycloid profile and modified cycloid profile are established based on gear meshing and differential geometry, and the tooth shapes of three different modifications are compared with CBR25 reducer. Third, the conventional TCA method is described and a new TCA method by using discretized points is proposed to calculate transmission error and contact force of cycloid drive. Both the methods are used to compute the unloaded transmission error of CBR25 reducer to compare the computational efficiency. Finally, three different modified methods of tooth profile are investigated by using the new TCA method to calculate transmission error and contact force of CBR25 reducer, and the results show that the negative isometric and negative offset modified method is best for CBR25 reducer to reduce transmission error and contact force. The prototype of CBR25 reducer is manufactured and the transmission error and hysteresis curve are measured by using a testing bench. The results show that the new TCA method can be used to calculate transmission error and help better design the CBR reducer.


Author(s):  
Xiaoxiao Sun ◽  
Liang Han ◽  
Jian Wang

China Bearing Reducer (CBR) is a one-stage cycloid speed reducer, which has the advantages of large transmission ratio, large load, high precision, high stiffness, and compact structure. The profile modification quality and manufacturing error of cycloid gear are the key factors affecting the transmission accuracy. In this paper, the structure of CBR is introduced first. By means of tooth contact analysis, a new parabolic profile modification method is proposed to improve the transmission accuracy. Then, by using Hertzian contact theory, force equilibrium equations and deformation compatibility conditions, a loaded tooth contact analysis algorithm of CBR is proposed to analyze the loaded transmission characteristics. According to the designed manufacturing error, the objective function is established to minimize the transmission error under nonload condition, and the particle swarm optimization algorithm is used to solve the optimal modification coefficients. Finally, the CBR25 is manufactured with the optimum modification coefficients, and the manufacturing error is measured in coordinate measuring machine to verify that it meets the design requirements. The optimal modification coefficients of CBR25 under nonload are solved based on particle swarm optimization model. Then the optimal modification coefficients are substituted to loaded tooth contact analysis to analyze the meshing contact force, contact deformation, and transmission error of CBR25. The transmission error of the CBR25 is tested on the testing rig. The error between the measured results and the calculated results of loaded tooth contact analysis is within 5%, which shows the correctness of the loaded tooth contact analysis algorithm. At the same time, the operation stability of the CBR25 is improved by using the optimal modification method.


2013 ◽  
Vol 437 ◽  
pp. 236-240
Author(s):  
Jian Jun Yang ◽  
Jian Jun Wang ◽  
Shi Min Mao

Flank modification is widely used in helical gear to diminish contact stress and edge contact, to improve the transmission performance. In this paper, tooth contact analysis is used to simulate the modified helical gear driver with high-order parabolic modification curve. The results show that the transmission error is diminished, and the meshing area is non-sensitive to the alignment errors.


Author(s):  
Layue Zhao ◽  
Robert C Frazer ◽  
Brian Shaw

With increasing demand for high speed and high power density gear applications, the need to optimise gears for minimum stress, noise and vibration becomes increasingly important. ISO 6336 contact and bending stress analysis are used to determine the surface load capacity and tooth bending strength but dates back to 1956 and although it is constantly being updated, a review of its performance is sensible. Methods to optimise gear performance include the selection of helix angle and tooth depth to optimise overlap ratio and transverse contact ratio and thus the performance of ISO 6336 and tooth contact analysis methods requires confirmation. This paper reviews the contact and bending stress predicted with four involute gear geometries and proposes recommendations for stress calculations, including a modification to contact ratio factor Zɛ which is used to predict contact stress and revisions to form factor YF and helix angle factor Yβ which are cited to evaluate bending stress. The results suggest that there are some significant deviations in predicted bending and contact stress values between proposal methods and original ISO standard. However, before the ISO standard is changed, the paper recommends that allowable stress numbers published in ISO 6336-5 are reviewed because the mechanisms that initiate bending and contact fatigue have also changed and these require updating.


2000 ◽  
Vol 122 (1) ◽  
pp. 109-122 ◽  
Author(s):  
Claude Gosselin ◽  
Thierry Guertin ◽  
Didier Remond ◽  
Yves Jean

The Transmission Error and Bearing Pattern of a gear set are fundamental aspects of its meshing behavior. To assess the validity of gear simulation models, the Transmission Error and Bearing Pattern of a Formate Hypoid gear set are measured under a variety of operating positions and applied loads. Measurement data are compared to simulation results of Tooth Contact Analysis and Loaded Tooth Contact Analysis models, and show excellent agreement for the considered test gear set. [S1050-0472(00)00901-6]


2013 ◽  
Vol 834-836 ◽  
pp. 1290-1294
Author(s):  
Xin Qin Liu

Mechanicalmethods were employed to study the motion and force transmission performance ofa kind of connecting rod slider mechanism with a curved edge driving component.The deduction methods and the computation formulae of the slider displacement,velocity, acceleration and the executive force gain coefficient were given.Considering two cases of the driving components with straight line edge andexponential function edge, the numerical examples was computed respectively,the results show that the former one is suitable for the force transmission andcan be used in the grip design and the other one is suitable for the motiontransmission which can be used in the fast moving mechanism


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