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:
Oct. 13, 1981
Filed:
Dec. 29, 1978
Peter H Sheppard, Hanover, PA (US);
Other;
Abstract
An integral power steering gear assembly includes a piston and cylinder combination having greater output efficiency through improved fluid balancing and cushioning of the piston at its ends. The improved cushioning utilizes oil capillary slots in lieu of previously proposed epoxy resin strips. The slots may be fed with high pressure fluid filled by feed grooves along the sides of the piston adjacent the output rack. The slots are designed to have a shallow depth, preferably 0.001 inch-0.0025 inch, which is sufficient to provide for high capillary attraction of the oil molecules to the slot. The trapped oil molecules prevent slip stick action, that is molecular interaction between the piston and cylinder wall, but at the same time, the oil molecules remain trapped or isolated within the walls of the slot thereby minimizing leakage from the slot. The operating oil is delivered with higher efficiency in the power steering unit by a bifurcated oil delivery passage communicating with the inlet slot of the piston. This provides fluidized balance and cushioning of the valve within the piston, and also prevents starvation of the high pressure feed grooves and capillary slots for balancing and cushioning the piston within the cylinder. Accordingly, improved reversibility of both the piston and the valve are obtained.