Sleeve for rotary valve
First Claim
1. A sleeve for a rotary valve of a hydraulic power steering gear, the rotary valve comprising a valve housing having an inlet port to receive hydraulic fluid from a pump, a return port to return hydraulic fluid to the pump, and cylinder ports to communicate hydraulic fluid to left and right hand cylinder chambers of the power steering gear, an input-shaft journalled within said sleeve, an array of eight axially extending blind-ended slots formed in the bore of said sleeve, and array of two primary and two secondary axially extending return channels also formed in the bore of said sleeve and interposed between respective adjacent slots, said primary return channels being substantially diametrically opposed within said bore, said secondary return channels also being substantially diametrically opposed within said bore and being angularly spaced from said primary channels by substantially 90 degrees, said channels extending to at least one axial extremity of said bore and arranged to axially communicate hydraulic fluid to the return port externally with respect to said input-shaft, wherein the radial depth of said secondary return channels is substantially less than the radial depth of said primary return channels at said axial extremity.
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Accused Products
Abstract
A rotary valve of a hydraulic power steering gear includes an input-shaft journalled within a sleeve. In the bore of the sleeve, an array of eight axially extending blind-ended slots and an array of two primary and two secondary axially extending return channels are formed. The primary return channels are diametrically opposed, and the secondary return channels are diametrically opposed. The return channels extend to at least one axial extremity of the bore to communicate hydraulic fluid to a return port. Further, the radial depth of the secondary return channels is substantially less than the radial depth of the primary return channels at or near the axial extremity.
14 Citations
10 Claims
- 1. A sleeve for a rotary valve of a hydraulic power steering gear, the rotary valve comprising a valve housing having an inlet port to receive hydraulic fluid from a pump, a return port to return hydraulic fluid to the pump, and cylinder ports to communicate hydraulic fluid to left and right hand cylinder chambers of the power steering gear, an input-shaft journalled within said sleeve, an array of eight axially extending blind-ended slots formed in the bore of said sleeve, and array of two primary and two secondary axially extending return channels also formed in the bore of said sleeve and interposed between respective adjacent slots, said primary return channels being substantially diametrically opposed within said bore, said secondary return channels also being substantially diametrically opposed within said bore and being angularly spaced from said primary channels by substantially 90 degrees, said channels extending to at least one axial extremity of said bore and arranged to axially communicate hydraulic fluid to the return port externally with respect to said input-shaft, wherein the radial depth of said secondary return channels is substantially less than the radial depth of said primary return channels at said axial extremity.
- 6. A sleeve for a rotary valve of a hydraulic power steering gear, the rotary valve comprising a valve housing having an inlet port to receive hydraulic fluid from a pump, a return port to return hydraulic fluid to the pump, and cylinder ports to communicate hydraulic fluid to left and right hand cylinder chambers of the power steering gear, an input-shaft journalled within said sleeve, an array of eight axially extending blind-ended slots formed in the bore of said sleeve, an array of two primary and two secondary axially extending return channels also formed in the bore of said sleeve and interposed between respective adjacent slots, said primary return channels being substantially diametrically opposed within said bore, said secondary return channels also being substantially diametrically opposed within said bore and being angularly spaced from said primary channels by substantially 90 degrees, said channels extending to at least one axial extremity of said bore and arranged to axially communicate hydraulic fluid to the return port externally with respect to said input-shaft, wherein the radial depth of said secondary return channels is substantially less than the radial depth of said primary return channels near said axial extremity.
Specification