Abstract: A power steering gear assembly 10 which is used to turn steerable vehicle wheels 50, 52 includes a piston 20 disposed in a motor cylinder 16. A series 44 of rack teeth are connected with the piston 20. A first tooth space 94 is formed between first and second teeth 80, 76 in the series 44 of rack teeth. The first tooth space 94 has a root portion 126 which includes first and second fillets 132, 136. The first fillet 132 has a larger radius of curvature 130 than the second fillet 136. The first and second fillets 132, 136 have centers of curvature which are both disposed between a central axis 104 of the first tooth space 94 and the second rack tooth 76. The center pinion gear tooth 190 has side surfaces 200 and 202 with intermediate portions 216 and 230 which are offset from continuously curving spatial envelopes 212 and 228 containing tip end portions 208 and 222 and root end portions 210 and 224 of the center pinion gear tooth.

Abstract: An improved valve assembly (100) includes a primary spring (142) which extends along a valve stem (144). A spring retainer (150) holds the primary spring (142) on the valve stem (144) and has a thread convolution (152) which engages a thread convolution (154) on the valve stem (144). The spring retainer (150) has a force transmitting surface (182) which engages a reference surface (184) on the valve stem (144) with a retainer preload force which is at least as great as a primary spring preload force. Shims (158–162) are provided between the primary spring (142) and the spring retainer (150) to enable a desired primary spring preload force to be obtained.

Abstract: A hydraulic power steering system (10) for turning steerable wheels of a vehicle. The system (10) comprises a steering gear (12) including a hydraulic motor and a steering valve. The steering gear is susceptible to pressure fluctuations that cause noise during steering. The system (10) further comprises a pressure relief valve (14) having an unactuated condition and actuated conditions. The pressure relief valve (14), in the unactuated condition, restricts fluid flow through the pressure relief valve (14). In an actuated condition, the pressure relief valve (14) permits fluid flow through the pressure relief valve (14). The pressure relief valve (14) progressively is operable from the unactuated condition to an actuated condition as a pressure differential between the inlet (38) and the outlet (40) of the steering gear (12) increases.

Abstract: A hydraulic power steering gear (10) for a vehicle comprises first and second valve members (40 and 42) which are disposed coaxial to one another and which are relatively rotatable about a first axis (38) to selectively port hydraulic fluid. The first valve member (40) has an associated axial bore (170). The axial bore (170) has a second axis (174) which extends parallel to the first axis (38). The second valve member (42) includes a cam surface (128). A plunger (200) is disposed in the axial bore (170) for movement along the second axis (174). The plunger has a detent surface (208). Springs (240) bias the plunger (200) axially toward the second valve member (42). A detent roller (220) acts between the first and second valve members (40 and 42). The detent roller (220) is located in the cam surface (128) and in the detent surface (208) in a neutral condition to provide a physically perceptible indication to a driver of the vehicle of operation between the neutral condition and an actuated condition.

Abstract: An apparatus (10) for use in turning steerable wheels of a vehicle having an engine includes a first gear (16) which is rotatable about a first axis (24) and a second gear (14) having teeth (20) in meshing engagement with teeth (18) on the first gear (16). The first gear (16) is movable along the first axis (24) to reduce clearance between the teeth (18) and (20) of the first and second gears (16) and (14). Adjustment of the first gear (16) along the first axis (24) is prevented during operation of the engine of the vehicle. Adjustment of the first gear (16) along the first axis (24) is enabled when the engine of the vehicle is in a non-operational condition.

Abstract: A power steering assembly (10) includes a rotatable valve core (40) which is encircled by a rotatable valve sleeve (41). The valve core (40) and valve sleeve (41) have surfaces which cooperate to direct a flow of power steering fluid during relative rotation between the valve core (40) and valve sleeve (41). A bearing assembly (100) is disposed between the valve core (40) and the valve sleeve (41) at a location adjacent to an axially outer end portion of the valve core (40). The bearing assembly (100) includes a plurality of rotatable bearing elements (124) which transmit sidewise loads between the valve core (40) and the valve sleeve (41). A bearing surface (102) is disposed on an axially inner end portion of the valve core (40). The bearing surface (102) is slidable along an inner surface area (104) on the valve sleeve (41) to transmit a sidewise load during relative rotation between the valve core (40) and the valve sleeve (41).

Abstract: A hydraulic power steering gear (10) comprises first and second relatively rotatable valve members (40 and 42). The first valve member (40) includes a radially extending passage (64). The second valve member (42) has an arcuate cam surface (184). A detent member (220) acts between the first and second valve members (40 and 42). The detent member (220) has a curved outer surface (252). A spring (240) biases the detent member (220) radially outward against the cam surface (184). The spring (240) is disposed in the radially extending passage (64) in the first valve member (40). The detent member (220) is disposed in the arcuate cam surface (184) in the neutral condition and provides a physically perceptible indication to a driver of the vehicle of operation of the steering gear (10) between the neutral condition and the actuated condition.

Abstract: To adjust the maximum torque required to actuate a hydraulic steering mechanism, the steering mechanism is first adjusted to provide a relatively high preload on gear teeth in the steering mechanism. The steering mechanism is then operated through a predetermined number of break-in cycles. After oil has been purged from the steering mechanism the steering mechanism is operated through one complete operating cycle and the location where the maximum torque is required to effect operation of the steering mechanism is noted. Preload between the gear teeth is then reduced and the steering mechanism is operated to the position where it was previously noted that maximum torque was required to actuate the steering mechanism. The steering mechanism is there dithered to either side of the location where the maximum torque was required. As this is done, the steering mechanism is adjusted to obtain the desired maximum operating torque for the steering mechanism.

Abstract: A vehicle steering apparatus (10) includes a first gear (16) which is rotatable about an axis (21), and a second gear (14) having gear teeth (18) in meshing engagement with gear teeth (20) on the first gear (16). The apparatus further comprises an adjustment mechanism (22) for moving the first gear (16) in one direction along the axis (21) to reduce clearance between the meshing gear teeth (18, 20). The adjustment mechanism (22) includes a first threaded member (64), a second threaded member (90) and a ratchet drive (98). The first threaded member (64) is movable along the axis (21) in the one direction to move the first gear (16) along the axis in that direction. The second threaded member (90) is screwed together with the first threaded member (64) such that rotation of the second threaded member (90) causes axial movement of the first threaded member (64).

Abstract: A valve (10) for controlling flow of hydraulic fluid. The valve (10) includes first and second valve members (80, 82), each having a plurality of lands and grooves. The valve members (80, 82) are relatively movable from a neutral position to a displaced position in which surface segments (202, 226, 208, 218) of respective pairs of lands overlap to form flow gaps (232, 234) for restricting flow of fluid between respective pairs of grooves. At least one (234) of the flow gaps is divergent by having a cross-sectional flow area which increases along a direction of fluid flow therethrough and at least one (232) of the flow gaps is convergent by having a cross-sectional flow area which decreases along a direction of fluid flow therethrough. The flow gaps (232, 234) have minimum cross-sectional flow areas (A, B) defined by the surface segments.

Abstract: A valve (10) for controlling flow of hydraulic fluid. The valve (10) has first and second valve members (80, 82) which have a plurality of lands and grooves. The valve members (80, 82) are relatively movable from a neutral position to a displaced position in which surface segments (202, 226, 208, 218) of respective pairs of lands overlap to form flow gaps (232, 234) for restricting flow of fluid between respective pairs of grooves. At least one (234) of the flow gaps is divergent by having a cross-sectional flow area which increases along a direction of fluid flow and at least one (232) of the flow gaps is convergent by having a cross-sectional flow area which decreases along a direction of fluid flow. The flow gaps (232, 234) have minimum cross-sectional flow areas (A, B) defined by the surface segments.

Abstract: A steering gear assembly (12) for a vehicle having steerable wheels includes a housing (14) defining a chamber (16) and a piston (18) movable through a work stroke in the chamber. The piston (18) is connected for movement with the steerable wheels of the vehicle. An actuator assembly (10) for adjusting the end-of-stroke position of the piston (18) is mounted in the housing (14) in a first orientation. The adjusting assembly (10) is removable from the housing (14), and is mountable in the housing in a second orientation opposite to the first orientation to reset the end-of-stroke position of the piston. The adjusting assembly (10) includes a pin (130) press fit in a sleeve (110) and movable in the sleeve to set the end-of-stroke position of the piston (18). The pin (130) and sleeve (110) are movable from a first position mounted in the housing (14) in a first orientation to a second position in which the pin and sleeve are mounted in the housing in a second orientation opposite to the first orientation.

Abstract: A valve for controlling flow of hydraulic fluid. The valve includes first and second relatively movable valve members (60 and 62). The valve members (60 and 62) include cooperating surfaces (112, 142, 144) which define first and second orifices for metering fluid from a pressurized fluid source (44) toward first and second locations (22 and 24) in a fluid utilization device (12). The valve members (60 and 62) have a displaced position in which the first orifice is increased in size and the second orifice is decreased in size. The increased size of the first orifice reduces a pressure drop across the first orifice. The decreased size of the second orifices increases a pressure drop across the second orifice. The valve members (60 and 62) include means (114 and 146) for increasing a pressure on a downstream side of the second orifice to reduce the pressure drop for controlling valve noise.

Abstract: A vehicle steering for turning the steerable wheels of a vehicle having a fluid motor with a housing defining a fluid chamber and a piston in the chamber dividing the chamber into first and second chamber portions. A rotatable steering input member is supported by the housing. A rotatable follow-up member is associated with the piston and rotatable upon movement of the piston in the chamber. A valve controls pressurized fluid flow to the first and second chamber portions. The valve comprises first and second relatively movable valve parts. One of the valve parts is connected with the input member and the other of the valve parts is connected with the follow-up member forming a unit therewith. The unit has a surface against which fluid pressure in the first and second chamber portions acts tending to create an axial force on the unit. Pressure is applied to another surface area of the unit to balance the axial force acting on the unit.

Abstract: A vehicle steering for turning the steerable wheels of a vehicle having a fluid motor with a housing defining a fluid chamber and a piston in the chamber dividing the chamber into first and second chamber portions. A rotatable steering input member is supported by the housing. A rotatable follow-up member is associated with the piston and rotatable upon movement of the piston in the chamber. A valve controls pressurized fluid flow to the first and second chamber portions. The valve comprises first and second relatively movable valve parts. One of the valve parts is connected with the input member and the other of the valve parts is connected with the follow-up member forming a unit therewith. The unit has a surface against which fluid pressure in the first and second chamber portions acts tending to create an axial force on the unit. Pressure is applied to another surface area of the unit to balance the axial force acting on the unit.

Abstract: A first locator engages lands defining a first groove in a valve core to position that first groove accurately relative to a first pair of notch forming tools. The first pair of notch forming tools then engage axially extending edges of lands defining that first groove to form metering notches. The first locator and first pair of notch forming tools are disengaged from the valve core. Then, a second locator engages lands defining a second groove to accurately position the valve core relative to a second pair of notch forming tools. The second pair of notch forming tools engage the valve core to form metering notches in the edges of lands defining the second groove. The second locator and second set of notch forming tools are retracted from engagement with the valve core. Thus, the metering notches are precisely and independently formed relative to each land.