Continuously variable transmission hydraulic control system having two pressure regulating valves
US4685357A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 26, 1985 |
| Grant date | Aug 11, 1987 |
| Priority date | — |
| Expiry date | Nov 26, 2005 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16H61/66272
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A hydraulic control system for a continuously variable transmission having two variable-diameter pulleys, a belt connecting the pulleys to transmit power from one of the pulleys to the other, and corresponding cylinders for changing effective diameters of the pulleys. The control system comprises: a hydraulic source delivering a pressurized fluid; a first pressure regulating device for regulating the pressurized fluid to apply a first line pressure to one of the cylinders for controlling a tension of the belt; a flow control device for controlling flow of the fluid into and from the other cylinder to change the effective diameters of the pulleys to vary a speed ratio of the transmission; a second pressure regulating device provided between the hydraulic source and the first pressure regulating device to regulate the pressurized fluid to apply a second line pressure to the flow control device, the second line pressure being higher than a pressure in the above-indicated hydraulic cylinder or the first line pressure by a predetermined value; and a releasing device for releasing the second pressure regulating device from its regulating operation while the speed ratio of the transmissio…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.