Hydraulic actuating system for a pair of concurrently operating friction devices for the selection of speeds of a load-shiftable transmission
US4200008A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 28, 1977 |
| Grant date | Apr 29, 1980 |
| Priority date | — |
| Expiry date | Dec 28, 1997 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16H61/067
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A hydraulic control system of the type disclosed in U.S. Pat. No. 3,938,410 is improved by providing a 2-3 shift valve which connects a direct passage and a throttle-containing passage to the control valve for the second clutch or brake (second-friction device) while the pressure in the first clutch or brake (first friction device) is applied to one side of the second control valve, a restoring spring acting upon the opposite side of this second control valve. This valve establishes a threshold for the pressure in the first friction device such that the direct passage is connected to the second friction device below the threshold while the throttle-containing passage is connected to the second friction device at or above this threshold.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.