New Method to Achieve High Hydraulic Pressure and Improved Gear Pump Performance in Active Height Control (AHC) System 2019-01-0854
There are high demands to reduce the mass of the vehicles in order to deal with tight fuel economy regulations of vehicles in each country.
In this development, we have to develop the new lighter actuator for the AHC (Active Height Control Suspension) system. The reduction of the mass ‘5kg’ and the miniaturization of the system have been achieved by disusing an accumulator, which had assisted the output performance of the hydraulic gear pump on the AHC.
The new pump system, which could accumulate more high hydraulic pressure and release more fluid, is required. Realization of this high requirement, the clearance between top of the gear tooth and the surface of the aluminum housing is set to be zero. We have established the new method, called ‘Break-In Process’, to implement this distance shaving the surface by rotating the gear. However, this ‘shaving remaining’ which should be shaved in this process can cause increase of the friction loss of the pump. Therefore, we have clarified the mechanism that this ‘shaving remaining’ has been explained by the relation of the number of the gear teeth contacting the surface and their stress to the face during this process. In this paper, the method how to leave out the ‘shaving remaining’ is described.
Adapting this technology to the product design and the process, we have succeeded improving the performance of the pump without accumulator or other some additional equipment. And it has been decided to adopt this technology to new generation AHC.