Study Internal Gear Contact Forces

This example studies the contact forces between inner and outer spur gears.

Internal gears are ideal in applications for high-power transmission within small overall dimensions, like robot arms. In Figure 1, the outer gear serves as the driver and applies torque to the inner gear (ring). 

Figure 1: Internal gear.

The spurGear component can be switched to an internal gear by setting the isInnerGear to true as shown in Figure 2.

Figure 2: Gear parameter tab.

Figure 3 shows the contact forces that do not get entirely loose where the next teeth pair contacts.

Figure 3: Contact forces.

The contact pressure on the gear tooth is shown in Figure 4. The maximum pressure is around 320 MPa, which is well below the typical maximum allowable limit for contact pressure on a gear tooth (for case-hardened gears, the maximum allowable contact pressure is typically 800–2000 MPa, while for through-hardened gears it can be 1000–2500 MPa.)

Figure 4: Contact pressure.