Bearing Application Requirements
Rotary vane pumps produce hydraulic power for automatic transmissions.
Located in the cover of the transmission, they pull oil at low pressure from a sump in the bottom of the transmission and feed it at high pressure to the hydraulic system, transmission cooler and torque converter.
The vane rotor is supported by bearings at the front and back plates.
When mounted in the back plate, needle roller bearings can fail due to oil starvation, particularly after long periods of rest in different climatic conditions or during repeated stop-start operation.
GGB Automotive Bearing Solution
To improve pump reliability, GGB DP4® metal polymer cylindrical bearings underwent trials to determine the feasibility of replacing the needle roller bearings.
The rigorous, extensive testing program included operation at full pump power and different engine regimes from 500 to 7 000 rpm under boundary, mixed and hydrodynamic lubrication, stop/start operation and oil starvation.
The results of these tests confirmed that the metal-polymer composite cylindrical bushings provide superior pump reliability thanks to their excellent tribological performance of under dry, marginal and hydrodynamic lubricated operating conditions.
GGB Automotive Bearings - Benefits
The benefits offered by GGB DP4 self-lubricating cylindrical bearings are the following:
- Extended service life with self-lubricating bushings enriched with a PTFE based low friction bearing overlay which avoids bearing lining and shaft damage when running under dry or boundary lubrication conditions
- Thin walled, one-piece construction permits compact, lightweight pump design
- Easy assembly in the pump without the need for expensive tooling and equipment
- Environmentally friendly lead-free bearing composition