Wear of staggered helical gears

Staggered helical gears are used to transmit the motion between two staggered shafts in space. For a single gear, they are helical gears. They have the advantages of simple manufacturing process, convenient transmission between any shaft intersection, convenient allocation of center distance and insensitivity to shaft intersection and center distance error.

Because staggered helical gears are point-contact drives, their contact stress is larger than that of parallel-shaft gears, their bearing capacity is lower, and they are prone to wear, so they are less used in power transmission structures.

A transmission uses a staggered helical gear structure to adjust its power source. Figure 1 shows a three-dimensional diagram of the transmission of the staggered helical gear, in which the number of active teeth is 23, the number of driven teeth is 35 and the normal modulus is 2.0.

The staggered helical gear drive wheel sleeve is mounted on the reducer rotor and drives the driven wheel to work by staggered helical engagement. The driven wheel then connects the adjustment system of the unit through splines to provide the adjustment power oil and lubricant for the unit.This transmission structure suffered from tooth surface wear failure of staggered helical gears in the test. Figure 2 shows the disassembly and inspection photos of driven and driving wheels of staggered helical gears.

After checking the heat treatment process and finite element calculation and analysis of the transmission staggered helical gear, the wear reason is determined. The unreasonable heat treatment process of the staggered signal helical gear is the main factor leading to wear.At the same time, according to the wear reasons, corresponding corrective measures are taken to improve the contact strength of tooth surface, i.e. carburizing and hardening the driving wheel and centrifugal casting the driven wheel.The 500-hour continuous running test shows that the wear resistance of staggered helical gears can be effectively improved by the measures taken.