Control system for powershift transmission clutches
US4843902A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 16, 1988 |
| Grant date | Jul 4, 1989 |
| Priority date | — |
| Expiry date | Jun 16, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T74/19405
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A control system for a multi-speed powershift gear transmission having multiple hydraulically actuated speed range clutches and directional clutches includes a control valve module having solenoid operated valves for conducting pressure fluid to a selected one of the speed range clutches and a selected one of the directional clutches. A pressure regulator valve is in circuit with the directional clutch control valves and is acted on by pilot pressure fluid controlled by a proportional solenoid type control valve wherein the pressure rate of rise in the directional clutches may be selectively controlled in accordance with the particular shift condition initiated and based on a previous transmission operating condition. The control unit provides for a predetermined pressure rate of rise signal to the pressure regulator valve based on the selected shift condition and the previous operating condition of the transmission.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.