Control arrangement for a variable pulley transmission
US4458318A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 24, 1981 |
| Grant date | Jul 3, 1984 |
| Priority date | — |
| Expiry date | Apr 24, 2001 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB60W2710/1005
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A continuously variable transmission (CVT) with adjustable width pulleys has its belt tension and ratio controlled by an electronic-hydraulic system. The CVT also has a fluid-cooled clutch on the output pulley shaft. The engine speed, transmission output speed, throttle position, and gearshift position are sensed, and signals representing this information are passed to a computer. The computer provides set point signals denoting desired engine speed, line pressure, and clutch cooling condition to a control system. An electromechanical valve assembly regulates fluid flow to the CVT primary sheave, to control CVT ratio as a function of the computer provided set engine speed signal. A second electromechanical valve assembly controls the line pressure in the hydraulic system, which is applied to the secondary pulley to maintain belt tension, as a function of the set pressure signal provided by the computer. A solenoid-operated valve, regulated by the control system, either returns waste fluid from the second valve assembly directly to sump, or passes the fluid to the clutch when cooling is indicated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.