Hydraulic gear-shift control for automotive transmission systems
US4005620A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 23, 1975 |
| Grant date | Feb 1, 1977 |
| Priority date | — |
| Expiry date | Apr 23, 1995 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16H61/029
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
To control the changeover between different speed ratios in an automotive transmission, with the aid of hydraulically actuatable clutches and brakes, a 1-2 shift valve (70) and a 2-3 shift valve (90) responsive to a speed-dependent fluid pressure are subjected to a countervailing load-dependent fluid pressure generated by a throttle valve (40), under the control of the vehicular accelerator, above a predetermined intermediate point of the load range. Fluid for the actuation of the clutches and brakes, under a pressure rising in the lower part of the load range and remaining constant in its upper part, is delivered by a modulating valve (340) in cascade with the throttle valve, provided with a limitedly displaceable slider, or by cascaded modulating and limiting valves (350, 357).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.