Electro-hydraulic actuator for motor vehicle brake
US6305758A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 16, 1999 |
| Grant date | Oct 23, 2001 |
| Priority date | — |
| Expiry date | Mar 16, 2019 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB60T8/4081
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
An electro-hydraulic actuator for a motor vehicle brake-by-wire brake system including a housing, a piston bore in the housing, a T-shaped piston in the piston bore, and an electric motor connected to the piston through a speed reducer. The T-shaped piston includes a disc-shaped head in the piston bore and a tubular stem perpendicular slidable in and out of the piston bore through a sealed guide in the bottom of the piston bore. The top side of the piston head opposite the stem constitutes a large effective area of the piston for rapidly expelling a relatively large volume of fluid from the piston bore in a low pressure interval of operation the actuator. When the fluid pressure in the piston bore exceeds a transition pressure, a transition valve opens a bypass passage to the piston bore behind the piston head so that the same fluid pressure reacts against the bottom side of the piston head around the stem. A high pressure interval of operation of the electro-hydraulic actuator then ensues in which the effective area of the piston is reduced to the area of the cross-sectional profile of the stem.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.