Hydraulic servo mechanism of automatic transmission for vehicle
US4748809A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Mar 26, 1986 |
| Grant date | Jun 7, 1988 |
| Priority date | — |
| Expiry date | Mar 26, 2006 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16H59/50
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
In an automatic transmission, friction elements are engaged and disengaged by a hydraulic servo connected alternately to a pressure source or to a drain through a selector valve, and an accumulator is connected to the line between the selector valve and the servo. The resistance against the oil discharged from the accumulator, the resistance against the oil discharged from the servo, and the return biasing forces in the accumulator and servo are adjusted so that the hydraulic pressure at the servo is lower than the hydraulic pressure of the accumulator for a predetermined time when the selector valve connects the servo with the drain. In one embodiment, a relief valve responsive to a vehicle running condition, controls the discharge rate of working oil through the drain. In another embodiment, a pressure regulator varies the level of the pressure of the working oil discharged from the accumulator in response to variations in a vehicle running condition.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.