Speed ratio control system for a continuously variable transmission for vehicle
US4743223A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 3, 1986 |
| Grant date | May 10, 1988 |
| Priority date | — |
| Expiry date | Jun 3, 2006 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16H61/66259
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A speed ratio control system for a continuously variable transmission is provided, wherein an oil flowrate to a hydraulic servo of an input or an output V-shaped pulley device is varied by a flow control valve, so that a speed ratio between the input and the output sides can be continuously changed. The system determines a deviation between a target value and a measured value and corrects the measured value in accordance with at least the characteristics of the flow control valve, so that the deviation and a rate of change per unit time of the speed ratio, or the deviation and a rate of change per unit time of a rotational speed of the input or output pulleys, will have a linear relationship over the entire area of control. This system avoids poor feedback gain because of the non-linearity of the characteristics of the flow control valve. Thus, the feedback gain is acceptable over the entire area of control of the continuously variable transmission. Even when the conditions of use are different, the speed ratio (or the input or output rotational speeds) can be stably controlled without disturbing the response.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.