2nd ICAI 2022

International Conference on Automotive Industry 2022

Mladá Boleslav, Czech Republic

In practice, all gearbox manufacturers try to reduce the impact of all the above mentioned influences on the contact pattern (i.e. the load capacity of the gearing) by selecting various modifications of the gear usable flank surfaces. These modifications are in the micrometre units, and therefore, in gear manufacturing, this is one of the most precise manufacturing processes in mass production engineering. However, there are other phenomena in the gearbox that change the contact pattern, such as bearing clearances. Whether shaft bearings or change gear bearings. This is the slope of the change gears at the stage when the gear is engaged, which transfers power from the engine to the drive train. These change gears are generally mounted on needle roller bearings with appropriate radial and axial clearance. At the time of power transfer through it, the change gear on the needle bearing relatively does not rotated compared to the shaft. The axial and radial clearance of the bearing due to the transmitted force causes a general spatial slope of the gear wheel (Figure 3), which in turn causes a change in the gear tooth contact pattern.

Figure 3: Display of the inclination planes of the change gear from the clearance on the needles

Source: Škoda Auto, a.s., internal materials

Similarly, the contact pattern is influenced by the clearance of the shaft bearings and their fit in the housing parts when load forces are applied. Specifically, how these structurally necessary radial and axial clearances of the change gear and shaft bearings affect the contact pattern was examined in more detail.

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