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With the progress of technology, the high-speed gear transmission device, which is widely used in energy, petrochemical and other fields, develops towards the direction of high power, high line speed, high efficiency and lightweight. The herringbone gear is usually used in this kind of transmission device, and its dynamic particularity under high speed conditions has an important influence on the reliable operation of the equipment. Therefore, the model of herringbone gear transmission is established, the dynamic characteristics of various herringbone gear transmission are analyzed under the conditions of driving and load excitation, the dynamic simulation is carried out, and the product is tested. The results show that when the load is constant, the greater the angular speed of the gear, the greater the contact force on the gear and the higher the collision frequency. When the input speed increases from 500 r/min to 1 000 r/min and 1 488 r/min, the difference of velocity fluctuation amplitude is 2.27 rad/s, 4.76 rad/s and 9.37 rad/s respectively, and the maximum contact force is 1.87 times and 2.44 times of that under 500 r/min, respectively. The number of angular velocity fluctuation increases to 1.94 times and 2.94 times of the case of 500 r/min, respectively. When the load increases, the angular velocity fluctuation of driven gears decreases and the contact force increases. This study provides reference for the design of this kind of high speed transmission devices.

In order to study the factors affecting the transmission performance of the steering gear used in agricultural intelligent cars, a small steering gear model is established by RecurDyn. Within the allowable range of the circumferential backlash of each gear group, the changes of different circumferential backlash are obtained by adjusting the tooth thickness of the gear group. The simulation of acceleration, deceleration and forward and reverse rotation of the steering gear model shows that when the circumferential backlash is 0.130 mm, the accuracy of the output gear 8 of the steering gear is relatively high and the return error is small. This research provides a theoretical basis for solving the driving accuracy problem of a smart car.

In this paper, the structure design and optimization of the column of the tree-shaped parking garage are carried out. The base dimensions are 2.4 m、0.7 m and 8.5 m respectively. The simplified model of column takes into account the axial stress caused by the total weight FN of each component and the bending stress caused by the suspended loading plate and the vehicle. The maximum stress is easy to occur at the root of the column. The calculated results are 63.06 MPa, less than allowable stress 117.5 MPa, maximum deflection 8.93 mm, much less than standard value 113.90 mm. In order to meet the requirements of strength and deflection displacement, the penalty function method is used to optimize the size of the main support of the column, and the optimized model is measured and compared with the software analysis. Under the same working condition, the stress change data at the root of the column are collected by the test instrument and compared with the software analysis. The stress at the same position is less than 10% of the deviation between the measured and the simulated analysis results. The design and analysis of column structure are carried out by combining finite element analysis with actual stress test, and the mixed penalty function method is used to optimize the column structure. The results show that the method is effective. It provides some means and reference for the analysis of this kind of project.

Precision speed reducer is one of the key parts of industrial robot. For a long time,its Core Technology has been monopolized by the several foreign developed countries,which seriously restricting the development of China robot industry.Technology development and its status of RV reducer at home and abroad were described in paper. Then,the main causes of restricting the development of our countries’ RV reducer have been detailed analyzed. Relevant documents and policies were sketched,which play an active role in promoting the RV reducer. Finally,some personal opinions and suggestions on how to improve the situation of our countries’ precision speed reducer were submitted.

With the development of industry,harmonic gear drive technology has been more and more applied with its special advantages. The principle,characteristics and application of harmonic gear drive are briefly introduced,the domestic and foreign development situation of it is briefly summarized,a detailed analysis of the research focus and development trend,and general discussion are carried out.

The flexible gear is the key parts of harmonic gear reducers,and its performance directly determine the overall condition of harmonic drives. In order to seek the basic law of influence of flexible gears wall thickness on its performance to make use of the law,the influences of flexible gears wall thickness on stress and deformation of the flexible gears are simulated and analyzed by ANSYS Workbench software under no-load and load conditions. The results show that,the maximum stress of the flexible gear increases and the maximum deformation decreases with the increase of the wall thickness under no-load condition. With the increase of the wall thickness,under the load condition,the maximum stress decreases overall and the maximum deformation decreases first and then tends to be gentle. Under the same wall thickness,with the increase of the load,the maximum stress and the maximum deformation both enhance and the load is more sensitive to the deformation in the places whose wall thickness are relatively thinner. Under the same conditions,the stress of flexible gear with bottom modification is smaller. This law can provide some reference for researchers.

The calculation of harmonic gear meshing stiffness is the basis of dynamics analysis. According to the finite element analysis theory of loading contact,and combining with its static and dynamic contact properties,taking each different location during one engaging-in and engaging-out cycle of a tooth as the research object. Then,by extracting the meshing data of discrete point on contact location,the curve of single-tooth stiffness and the synthesizing meshing stiffness in one engaging-in and engaging-out is got. Comparing with the previous researching result,the correctness of the method is verified,which provides the basis for dynamics analysis for harmonic gear.

Aiming at the cycloid transmission in the cycloid planetary gear speed reducer used for robot,the analysis model for return clearance and mesh force calculation of cycloid transmission is set based on gear meshing theory and dynamic multi teeth meshing property. The influence of different tooth modification methods on the number of meshing teeth,force and distortion of each mesh point and the return clearance of cycloid transmission is calculated through iterative method. Furthermore,the influence of the load on the meshing characteristic is analyzed,and the stiffness curve of the cycloid transmission is obtained with the increase of load. It provides basis for the design and torsional vibration analysis of cycloid transmission.

In view of the stress of flexspline calculated on the basis of the theory of thin-walled cylinder,there are many assumptions of the theory,which will lead to the difference between the calculated value and the actual value. Considering the boundary constraint and force,from theoretical model to actual model,six analysis model are constructed based on the geometric model of flexspline to research the difference between theoretical and actual by finite element method. The result of analysis indicate that the maximum value appears in the gear root which is close to the cup bottom of flexspline,and accompanying the transition from theoretical model to actual model,the stress of all direction is increased gradually,which the circumferential stress has a larger increasing range. The reason of that is the stress concentration caused by the boundary constraint.

The radial deformation is one of the important parameters that affect meshing characteristic and the life of flexspline in harmonic reducer. Based on envelope meshing theory of harmonic drive,the influence of radial deformation on meshing characteristic of harmonic drive is analyzed. The finite element method is used to obtain the stress distribution of the flexspline. The results show that the radial deformation has significant influence on the meshing track,the radial deformation of the flexspline,the tangential deformation,the rotation angle in normal direction,the bending stress and the tangential stress of the flexspline. The result of the flexspline stress distribution from theoretical calculation has good consistent with the result from finite element analysis.This can provide some reference for the choosing of reasonable radial deformation to improve meshing performance and life of flexspline.

The inherent characteristics of the high speed shaft and the unbalance response of the high speed shaft seriously affect the operating condition and service life of the high speed gearbox. For the high speed gear shaft,a multi distribution model of the system is established. The natural frequency and the unbalance response of the shaft are analyzed by using the transfer matrix method. The unbalance response of the shaft at different speeds and different eccentric quality is obtained with the same method. The unbalance response of the gear meshing point is investigated through the analysis of the unbalanced response characteristics in various cases,and the working conditions of the gear meshing point are analyzed,and the basis for the design and manufacture of high speed gear box is provided.

The characteristic of precision planetary reducer are small size,high precision,small backlash and high stiffness.So it is widely used in robotics,machine tools,medical,military,printing and other industries.But the fatigue failure is easily to occur in precision planetary reduce for its small module,wide speed range and variable load.According to the characteristic of precision servo reducer,the gear dynamic meshing force and fatigue life of planetary gear train are obtained through the dynamics and collaborative simulation.The results show that the sun gear which is the weakness of system can well meet the design requirements.This method which using the dynamic meshing force to analyze the fatigue life of precision servo reducer is more in line with the actual working condition of the reducer.And it can provide the basis for product design and development.

The backlash is an important indicator of cycloid drive,and the modification is a major factor.Comprehensively considering the bearing capacity and backlash of the whole machine,the modification optimization of the cycloid gear is carried out by using the Matlab optimization tools,and a conclusion that high precision cycloid drive adopting " negative equidistance + negative shift" composite modification will get ideal cycloid gear profile is obtained.