Influence of contact force on temperature of helical gear tooth surface

In order to study the influence of temperature on the contact force of helical gear tooth surface, the tooth surface friction coefficient is set as 0.5 1. Other parameters remain unchanged. The variation curve of torque of 1500N · m is shown in Figure 1.

Considering the friction heat between teeth into the helical gear contact analysis model, the helical gear tooth surface generates heat due to mutual contact friction, resulting in the increase of helical gear tooth surface temperature; As the temperature increases, the average kinetic energy between the material molecules will increase, resulting in relative movement between the molecules, resulting in the decrease of the interaction force between the molecules, and finally the relative decrease of the yield stress and the contact pressure of the material; Then, the material begins to soften, and the contact area will gradually expand, so the contact force of helical gear tooth surface will decrease. To sum up, the maximum value of helical gear tooth surface contact force considering temperature is lower than that without considering temperature; It shows that the contact temperature of helical gear tooth surface will have a certain influence on the contact force, but the influence is not obvious.

The friction of helical gear tooth surface will soften the contact surface and increase the contact area. Due to the extrusion of molecules in the body and the transfer of temperature to the helical gear body, the thermal stress will be generated on the secondary surface. Therefore, as shown in Figure 2, the secondary surface stress considering temperature in a certain depth is greater than that without considering temperature, and the stress of both will gradually decrease with the increase of depth. In order to study the effect of temperature on plastic deformation, Fig. 3 (a) and Fig. 3 (b) show the plastic regions without considering temperature and considering temperature respectively.

Considering the temperature, the extension direction of the center of the plastic deformation region shifts, which is due to the distortion of the subsurface stress due to the uneven distribution of the subsurface temperature; In a certain depth, the stress considering temperature is higher than that without considering temperature, so the area of plastic deformation will increase accordingly.

Figure 4 shows the temperature field distribution of the helical gear tooth surface of driving wheel 2, and extracts the temperature change curves of four paths along the direction of tooth height and tooth width respectively. According to the figure, the maximum temperature of the contact surface is 67 About 61 ℃, near the root of the tooth; The secondary high temperature is 58 82 ℃, near the tooth top; Because the relative sliding speed at the alternation of two tooth meshing and three tooth meshing is large, and the heat flux generated by friction is positively correlated with the relative sliding speed, the heat flux increases when the tooth meshing is alternating, so there are two local temperature peak areas on the contact tooth surface. It can be seen from routes 1, 2 and 3 that the middle temperature of the temperature field along the tooth width direction of the helical gear is high and the temperature at both ends is low, which is caused by the convective heat dissipation of the mixture of the helical gear end face and the lubricating oil.

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