Trimmer valve with flow retention
US5492028A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 22, 1994 |
| Grant date | Feb 20, 1996 |
| Priority date | — |
| Expiry date | Sep 22, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T74/19251
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A hydraulic control for an automatically shifted power transmission has an electronically controlled governor pressure source which provides a speed and throttle sensitive pressure for controlling the shift points and trim boost in the transmission control. An inhibitor circuit is activated in the event of a discontinuance of the electrical control, resulting in maximum governor pressure, to permit selected vehicle operation in one forward ratio and a reverse ratio. Each ratio interchange is controlled by a respective shift valve and clutch control valve. Each clutch control valve has an integral trim control which is effective to control the pressure rise in the on-coming clutch without bypassing fluid to an exhaust. Also during a ratio interchange, an off-going clutch is controlled at a reduced pressure during a portion of the ratio interchange.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.