Abstract The invention relates to a metering type control unit for a power steering system. Units of this type most commonly utilize gerotor type gear sets for the metering operation. A problem with this unit is that highly pressurized fluid leaks from the expansible chambers formed between the star and ring members of the gerotor to the central bore of the star. Control units of this type require a universal drive between the rotatable valve thereof and the star which has a combination rotating and orbiting movement. In this invention the universal drive has a sealing flange associated therewith which serves to enclose the central bore of the star so that a fluid tight chamber is formed. Fluid is trapped in this central bore with the result that the pressure differential between the expansible chambers and this central bore is minimized and leakage is consequently minimized.
A metering unit for steering systems comprising a casing, a rotary piston in said casing having a rotatable movement relative to its own axis and an orbitable movement relative to the casing axis, a toothed ring member surrounding said piston, said piston having a central bore, a disk having a central bore attached to one side of said ring member, and a closure member attached to the other side of said ring member, said disk and said closure member constituting walls for expansible chambers formed between said rotary piston and said ring member, a rotary valve rotatable about said casing axis, a drive mechanism between said valve and said piston, said drive mechanism being in sealing engagement with said disk to enclose said piston central bore along with said closure member so that said piston central bore forms a fluid tight chamber.
Claim 2
Dependent Claim
142 words
A metering unit for steering systems comprising a casing, a rotary piston in said casing having a rotatable movement relative to its own axis and an orbitable movement relative to the casing axis, a toothed ring member surrounding said piston, said piston having a central bore, a disk having a central bore attached to one side of said ring member, and a closure member attached to the other side of said ring member, said disk and said closure member constituting walls for expansible chambers formed between said rotary piston and said ring member, a rotary valve rotatable about said casing axis, a drive mechanism between said valve and said piston, said drive mechanism being in sealing engagement with said disk to enclose said piston central bore along with said closure member so that said piston central bore forms a fluid tight chamber.
Claim 3
Dependent Claim
20 words
A metering unit according to claim 1 wherein said drive means includes a flange in sealing engagement with said disk.
Claim 4
Dependent Claim
50 words
A metering unit according to claim 1 wherein said casing has inlet and outlet ports, rotaty valve means including said rotary valve, said rotary valve means having a central bore, neutral position valve means for selectively providing fluid communication between said rotary valve means central bore and said outlet port.
Claim 5
Dependent Claim
15 words
A metering unit according to claim 1 wherein said drive means is an Oldham coupling.