Solenoid self-cleaning pressure valve for automatic vehicle transmission
US5971889A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 26, 1998 |
| Grant date | Oct 26, 1999 |
| Priority date | — |
| Expiry date | Aug 26, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/428
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A system for controlling an automatic vehicle transmission, including a gear system and hydraulic clutches which hold a member of the gear system stationary to produce gear reduction or reverse, having an oil line which connects the clutches to an oil pressure source, a pressure control valve having a solenoid provided in the oil line which generates a regulated oil pressure to be supplied to the clutches in response to a current supplied to the solenoid, a switch valve provided in the oil line which switches the oil pressure to be supplied to the one of the clutches between the regulated oil pressure and a line pressure. In the system, it is discriminated whether the pressure control valve does not supply the regulated oil pressure to the clutches and if so, a dither current is supplied to the solenoid such that the valve repeatedly performs a vibrational motion to remove any grit therefrom, thereby removing grit without causing gear-shift shock or clutch vibration.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.