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Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to solve the problem of calculation efficiency and accuracy of time-varying meshing stiffness of spur bevel gears, a slice calculation method of meshing stiffness of spur bevel gears considering the coupling effect of tooth pairs is proposed. Based on the slice discretization method, the bevel gear tooth and the gear body are discretized into several slices with the same width along the tooth width direction and the axis direction respectively, and the slices are expanded based on the back cone equivalence principle. When the slice width is small enough, the bevel gear can be approximated as a series of spur gears, and the meshing stiffness of each slice can be calculated by the energy method. In order to consider the coupling effect of multi-tooth meshing, the correction coefficient of gear stiffness is introduced in the calculation of double tooth meshing stiffness, which reduces the calculation error of double tooth meshing stiffness. The meshing stiffness model of bevel gears under the error condition is established. The meshing stiffness of spur bevel gears, the angular displacement of the center point of each slice and the load distribution of the tooth surface under the ideal and assembly error conditions are calculated and analyzed. Finally, the accuracy and efficiency of the proposed method are verified by comparing with the finite element calculation results.

Tooth surface equations of a curvilinear cylindrical gear with parabolic modification are derived based on the gear meshing theory. The solving method of the initial contact position of the gear finite element model is studied, a finite element model of the gear pair is established using the parameterized finite element technology, and the loaded transmission error is extracted from the finite element analysis results. With more than 20 sets of calculation examples, the effects of assembly errors, modification amount, curvature radius of the cutter, and offset of modification curve on loaded transmission errors are studied, respectively. The research results show that, assembly errors can reduce the fluctuation range of loaded transmission errors; larger modification amount can reduce the fluctuation range of loaded transmission errors; larger curvature radius of the cutter can reduce the value of loaded transmission errors and its fluctuation range; the offset of the modification curve has slight effect on loaded transmission errors. In summary, the use of a larger curvature radius of the cutter can be used to machine curvilinear cylindrical gears with better transmission performance.

Accurately identifying the error transfor path of the meta-action unit was the premise of error analysis. A new method was proposed to judge the error transmission path of the meta-action units based on the concept of DOF constraints in mechanical systems. Firstly, the DOF constraint requirements of the precision output parts and the initial error transfer path were determined by analyzing the functions and the structures of the meta-action units. Secondly, the constraint properties of the joint surfaces were analyzed, and the DOF constraint properties of the precision output parts were calculated along the error transfer path. The error transfer path was determined by comparing the obtained constraint property with the designed constraint property. Compared with traditional methods, the proposed method improves the efficiency of the analysis and identification of the error transfer paths greatly. [ABSTRACT FROM AUTHOR]

When spur gear pair meshing with the assembly error，it will cause the edge contact and stress concentration，and affect the service life. In the meantime，because the parallelism error of vertical plane will produce a larger deviation of tooth contact，therefore，taking the spur gear pair with the parallelism error of vertical plane as the research object，then based on the systematic introduction of the numerical calculation theory of gear contact stress，and the contact stress，contact width and the corresponding load distribution coefficient along the tooth in the case of different assembly error and load conditions are calculated，and the results calculated by numerical calculation method and national standard calculation method in the case of no assembly error are made a comparative analysis. The results show that the results calculated by two methods in the case of no assembly error are close to each other，and the numerical calculation result can reflect the edge effect of the gear pair meshing. Under the same load，with the increase of the installation error，the uneven contact in the tooth width direction becomes worse，and one side disconnects. Under the same assembly error，the uneven contact is improved with the increase of load，the maximum contact stress presents nonlinear increase with the increase of assembly error and load.

In order to solve the problem of measuring the assembly error of gear shafting in engineering， a method of measuring the assembly error of gear shafting based on stereo vision is proposed. In this method， the circular mark points arranged on the feature to be measured are used as the medium to obtain the spatial pose of the corresponding features through 3D reconstruction and mathematical fitting， and then the assembly error is calculated. Taking a bevel gearbox as an example， the complete technical process of the proposed method is given， and the influence of the number of States and the installation angle of the target plate on the fitting accuracy is systematically studied. A complete hardware and software system is developed， and the effectiveness and efficiency of the measurement method are verified by experiments.

Focusing on a planetary gear transmission that uses line gear as core transmission elements， and the influence of assembly errors on its transmission precision is studied. The structural composition of the line gear transmission and the characteristics of different transmission schemes are analyzed， the space meshing coordinate system for the gear train are established， and the quantitative relationship of the parameters at the meshing moment is established among the sun line gear， the outer ring line gear and the planetary line gear. The causes of the angle error and displacement error are analyzed， both between the planetary line gear and the sun line gear and between the outer ring line gear and the planetary line gear. Tooth Contact Analysis （TCA） is subsequently adopted to carry out the numerical analysis of the assembly errors model for the line gear transmission. The results show that， among assembly errors of the planetary gears， the angular errors of its rotation around the horizontal axis， the displacement errors in the longitudinal section of the outer ring line gear， and the displacement errors in the cross section of the planetary line gear， are of more effect on its transmission. That is of significant to design and assembly of the planetary gears.

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The speed integration gear is a new type of gear mechanism,which is meshed with cylindrical gears and non-circular face gear and can achieve speed integration transmission. Based on gear mesh theory,the tooth surface equation of non-circular face gear is deduced. Considering the angle error,intersected axis error and axis shift error,the contact model of tooth surface is established. An analysis of distribution characteristics of the contact path is made to obtain the influence of the assembly error on the point contact trace of the teeth. Simulation results indicate that the gradient of the contact path on each tooth of non-circular face gear increases with rate of change of the transmission ratio. The assembly errors cause the shift of the contact path to inner or outer radius,with its movement direction depending on the error direction.

Based on the principle of gear meshing,the precise 3 D solid geometry model of spiral gear is established. Then the finite element model of spiral gear for loaded meshing characteristics analysis is built,and the grid size of model is reasonably determined by the Hertz contact theory. Taking six teeth as research objects,the positions of the maximum contact and bending stresses of the spiral gear are found,and the stress curves are plotted in a meshing period. The analysis of meshing characteristics including contact patterns and paths on the gear surface is carried out by selecting the loading condition and assembly error as the variable respectively. The results provide a remarkable guiding role in the design and practical application of spiral bevel gear.

A parameterized model of the gear with assembly and manufacturing errors was established for the gear contact failure， and the dynamic tooth surface contact stress was simulated by using the large-deformation explicit dynamics simulation software. Then， the response performance function of the gear was built by the stress-strength interference model. A reliability analysis method based on response surface and the Markov chain Monte Carlo(MCMC) was proposed to improve the precision of the response performance function， and the dependability sensitivity analysis was conducted to quantify the effects of assembly errors， machining errors and stochastic external loads on gear transmission reliability. Finally， the correctness of this method was verified by comparing the results of 100000 Monte Carlo simulations with the results of the as-proposed method. [ABSTRACT FROM AUTHOR]