Power brake booster
US3939658A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 21, 1974 |
| Grant date | Feb 24, 1976 |
| Priority date | — |
| Expiry date | Oct 21, 1994 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB60T13/163
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A hydraulic power brake booster powered by power steering gear pump pressure and utilizing an open-center valve so that fluid flows through the booster without pressure reduction when the booster is not activated. The booster has two power chamber sections, both being pressurized at the same time under normal brake operation. However when the brakes are applied very fast, a high rate of pressure increase occurs in one chamber but not in the other due to a flow restriction between the two chambers. The booster piston assembly will therefore move in the brake applying direction more quickly than it would if the pressure fluid should be acting on the full power piston diameter since less displacement is momentarily required to build up the necessary pressure. The chamber section with the slower pressure buildup rate will increase in volume and be maintained full of fluid by a check valve arrangement extending through the piston and connecting with the low pressure side of the piston. This prevents a vacuum lock or retardation effect. A check valve is provided between the power chamber sections to allow flow from the chamber section with the slower pressure buildup rate to the chamber …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.