Nonlinear Vibration Characteristics of Involute Spur Gear Drive System

For single-stage gear drive system, engine excitation is taken as input condition, dynamic characteristics and parameter influence rules under steady-state and no-load conditions are analyzed, and motion forms of gear drive system under different conditions are analyzed by combining qualitative and quantitative analysis methods of non-linear dynamic characteristics.The main conclusions are as follows:

(1) For the gear drive system of heavy-duty vehicles, the effect of swing vibration on dynamic load is negligible.Especially when modeling and solving complex multi-stage gear drive system in heavy-duty vehicles, the degree of freedom of the system’s yaw-torsion coupling nonlinear dynamic model is more, which greatly affects the calculation efficiency. The influence of the yaw vibration can be ignored while ensuring the calculation accuracy and considering the calculation efficiency.

(2) Due to the coupling between gear meshing parameters and vibration response, the center distance, meshing angle, coincidence degree and meshing angle all change with time during actual gear transmission.With the increase of center distance, the engagement angle and clearance of gears also increase, while the amplitude of overlap and engagement stiffness in single and double teeth engagement area gradually decreases.The frequency component of meshing stiffness includes not only the rodent frequency and its frequency multiplication, but also the frequency conversion of each shaft.

(3) Under steady-state condition, with the change of engine speed, the system resonates when the meshing frequency and its frequency multiplication approach any natural frequency, resulting in a significant increase of dynamic load; with the increase of center distance deviation, the dynamic load of the gear increases approximately linearly; the central support stiffness has a significant influence on the dynamic characteristics of the gear transmission system; with the change of the central support stiffness, the dynamic load of the gear transmission system increases significantly.The natural frequency of the system also changes. When the natural frequency of any order approaches the meshing frequency of the system, the dynamic load of the system increases.In the design of gear drive system, the engagement frequency and its frequency multiplication should be avoided as far as possible to approach any natural frequency of the system.

(4) Under no-load condition, with the increase of no-load speed, there is no obvious change trend of maximum dynamic load on tooth surface and back, but the mean square root value of dynamic engagement force increases; with the increase of backlash or center distance deviation, the maximum impact load on tooth surface and back increases generally, but there are local peaks under individual parameters, while the mean square root value of engagement force approximates.Linear increase.When designing and assembling the gear drive system, the side clearance and center distance deviation should be minimized to reduce the dynamic load under no-load condition without jamming.

(5) Gear drive system under full throttle condition is a complex long-period motion, while gear drive system under no-load condition is a chaotic motion.It is difficult to distinguish long-period motion from chaotic motion from phase plane, so it needs to be judged by combining spectrogram, mapping map and maximum index.

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