The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 04, 1995
Filed:
Jun. 28, 1993
Joseph S VanSelous, Highland, MI (US);
Kenneth G Weidman, Brighton, MI (US);
Ford Motor Company, Dearborn, MI (US);
Abstract
A valve (36) for controlling pressure supplied to a friction clutch (32) of an automatic transmission includes several valve spools (38,40,44) each formed with control lands located within a bore (42) opening to various ports (60,66,68,72,76,80) that are supplied selectively with line pressure depending upon the operating state of the transmission. The valve operates in a primed condition, whereby a predetermined low pressure is supplied continually to the friction clutch. The valve supplies the clutch with a higher pressure that operates to stroke the clutch cylinder and friction element and thereafter regulates clutch pressure in accordance with changes in pressure in one of the ports. The clutch is stroked rapidly because the valve provides a relatively unrestricted supply of pressurized fluid through one of its inlet ports. After the clutch free-pack clearances are taken up, the valve restricts the clutch stroke against a cushion spring by opening the clutch cylinder to an orificed supply circuit. A delayed response to a change in operating state of the valve is minimized such that the control lands of the valve spools do not fully open line pressure supplied to the valve.