Reverse preselect control
US4495838A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 16, 1981 |
| Grant date | Jan 29, 1985 |
| Priority date | — |
| Expiry date | Dec 16, 2001 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T74/194
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
Disclosed is an automatic control system for a powershift, preselect transmission (10) including a plurality of power paths (36, 38) alternately connectable between input (12) and output (20) shafts by first engaging selected ones of synchronizer clutches (42, 74, 84) associated with each of a plurality speed ratio gears (44, 46, 76, 78, 80) in each path and then alternately engaging a powershift clutch (48, 82) associated with each path. The control system includes a hydraulic logic system (118) which may be electronic and a hydraulic and shift valve system which may be electrically controlled should the logic be electronic. The control system preselects ratio gears in a nondriving path and then alternately engages the powershift clutches to switch driving connections from one path to the other. The logic system includes an improved reverse sequence valve (132) and improved shift valves (124, 126, 128). The shift valve system includes the feature of trimmer valves (364, 370, 372, 374) to control the engagement rate of the synchronizer clutches and combination trimmer valves (360, 366) to control the engagement rate of the powershift clutches. The logic system further includes the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.