Impact vibration characteristics of planetary gear train

Planetary gear drive is widely used in various industrial fields due to its large power weight ratio, high load-carrying capacity and compact structure. Due to the wear of tooth profile and the machining error, the gear pair will have backlash, which will cause the repeated impact of contact, separation and re contact between gears. In this way, the impact of tooth surface is more obvious at high speed, and will cause strong vibration, which will affect the working performance and service life of the equipment.

Collision is a complex non-linear process, and its response is closely related to the relative velocity between collision objects, the topological structure of contact area and collision time. In gear dynamics, gear collision refers to the process of two meshing tooth surfaces from meshing state, relative motion to instantaneous contact, and then rapid rebound, which can be described by classical collision vibration theory. Kahraman et al. Analyzed the steady-state response of the system under internal and external excitation, and verified the existence of subharmonic vibration through experiments. Sun Tao compared the linear and nonlinear frequency response characteristics of planetary gear transmission, and analyzed the influence of time-varying stiffness, error and backlash on the nonlinear dynamic behavior of the system. The analysis models used in these studies include the clearance of the gear side or clutch, and the clearance is processed in a piecewise linear way, and simulated by a piecewise function, but the collision force and its influence of the gear surface are not considered, and the research objects are mostly fixed axle gear trains. By simplifying the meshed gear pair into a rectangular rack structure, barthod more intuitively describes the reciprocating impact vibration principle between the teeth, and studies the relationship between the impact vibration noise and the excitation frequency and amplitude. Dogan et al. Studied the influence of gear design parameters (number of teeth, modulus, helix angle, etc.) and operation conditions (input speed, excitation frequency, etc.) on the rattling vibration of reducer. Kadmiri et al. Believed that the impact recovery coefficient during the impact of the tooth surface directly affects the impact load generated at the moment of the gear impact [8]. At present, there are few literatures about the impact vibration of planetary gear transmission system.

ZHY gear combines Hertz contact theory to establish the analysis model of the impact vibration of the planetary gear transmission system, and analyzes the impact of operation conditions on the impact vibration characteristics of the planetary transmission system under large load and light load respectively. An analysis model of the impact vibration of planetary gear transmission system is established. By analyzing the influence of load and speed on the running state of planetary gear drive system, the following conclusions are obtained.

(1) Under the condition of large load and continuous increasing speed, the harmonic components of gear dynamic load are radially distributed, and the harmonic components fluctuate greatly at the natural frequency of the system.

(2) With the increase of load, the main frequency of gear impact force changes from second harmonic to meshing frequency, and the time of gear de meshing is gradually shortened until normal meshing.

(3) Under small load, with the increase of rotating speed, the time of de engagement is gradually shortened, and the fluctuation of impact force increases linearly.

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