The radial vertical load of needle roller bearing mainly comes from the radial force of gear

What factors are related to the fretting wear of needle roller bearings?

2. Influence factors and prevention of fretting wear

According to the analysis of the mechanism of fretting wear of needle roller bearings, there are three main influencing factors. They are: radial vertical load, displacement of reciprocating motion, and number of cycles. From the analysis of tribological mechanism, the wear degree is also affected by material hardness, surface roughness, lubrication and other factors.

2.1 Radial vertical load

The radial vertical load of the needle roller bearing mainly comes from the radial force of the gear. The greater the radial force, the greater the pressure acting on the contact part (less than 4000MPa), and the easier it is to aggravate the wear during relative movement. The size of the radial force of the gear is determined by the transmitted torque, which cannot be changed generally, and the pressure of the contact part can be reduced through the optimization of the needle roller bearing. The optional optimization scheme is to reduce local pressure, improve wear resistance and prevent fretting wear by increasing the length, number and diameter of needle rollers.

2.2 Displacement of reciprocating motion

The displacement of reciprocating motion is caused by the axial clearance (0.15~0.45mm) and radial clearance (0.015~0.058mm) of needle roller bearing. The larger the clearance, the greater the displacement of reciprocating motion, the faster the speed, the higher the friction work, and the easier it is to cause local wear. There are two optimization options: one is to reduce the axial clearance (0.1~0.35mm) by improving the axial positioning accuracy of gears and shafts; The other is to reduce the radial clearance (0.009~. 048 mm) by reducing the diameter tolerance of shaft and hole or grouping and matching the diameter tolerance of shaft and hole. Through the optimization of clearance, the displacement of reciprocating motion can be significantly reduced, the friction work can be reduced, and the fretting wear can be prevented.