Trw Limited

Henry C Sangret

George M Harpole

Michael B Petach

Michael A Jones

An apparatus (,) includes first (,) and second (,) meshing gears, a rotatable eccentric (,), a torsion spring (,), and a rotation blocking member (,). The first gear (,) is rotatable about a first axis (,) and the second gear (,) is rotatable about a second axis (,). The rotatable eccentric (,) supports the first gear (,) for rotation about the first axis (,). Rotation of the eccentric (,) in a first direction (,) causes the first axis (,) and the first gear (,) to move toward the second axis (,). The torsion spring (,) biases the eccentric (,) for rotation in the first direction (,). The rotation blocking member (,) prevents rotation of the eccentric (,) in a second direction (,) opposite the first direction (,).

Apparatus for automatic control of the clearance between gears

An apparatus (30) for use in pumping hydraulic fluid includes a pump unit (32) which is driven by an electric motor (34). The electric motor (34) is mounted on a tubular stem (108) which extends axially outward from a manifold plate (44). A stator (100) of the electric motor (34) is fixedly connected with the tubular stem (108). A rotor (112) of the electric motor (34) encloses the stator (100). A hydraulic muffler (50) attenuates noise produced by the gear pump unit (32). The hydraulic muffler (50) includes a channel (58) which extends into the manifold plate (44) from a major side surface (63) of the manifold plate. To increase the ability of the hydraulic muffler (50) to attenuate noise, one or two compliant elements (152 or 166 and 168) are connected with the channel (58).

Pump having muffler for attenuating noise

A power steering control valve (10) includes inner and outer valve members (30 and 32) which are rotatable relative to each other to control fluid flow to and from a power steering motor. A damping assembly (60) is provided to damp relative movement between the inner and outer valve members (30 and 32). The damping assembly (60) includes a pair of pistons (64 and 66) which are connected with the inner valve member (30) and extend into arcuate grooves (70 and 72) in the outer valve member (32). The pistons (64 and 66) cooperate with the arcuate grooves (70 and 72) in the outer valve member (32) to form variable volume chambers (76, 78, 80 and 82). Upon relative rotation between the inner and outer valve members (30 and 32) in a first (clockwise) direction, the pistons (64 and 66) are moved relative to the outer valve member (32) to contract a pair of chambers (76 and 82) and force fluid from the contracting chambers through restrictors (84 and 90) to a return fluid flow from the power steering motor. At the same time, movement of the pistons (64 and 66) expands a pair of chambers (78 and 80) to induce fluid flow through a second pair of restrictors (86 and 88) into the expanding chambers from the return flow of fluid to the power steering motor.

Power steering control valve

An apparatus for use in a vehicle to control a flow of fluid to a power steering motor includes inner and outer valve members (40 and 42) which are disposed in a housing (44) and are rotatable relative to each other to control fluid flow to a power steering motor (31). A force transmitting assembly (114) is provided to resist relative rotation between the inner and outer valve members (40 and 42) with a force which varies as a function of variations in force applied against the force transmitting assembly. An actuator member (130) is provided to apply force against the force transmitting assembly (114). A power steering resistance control system (110) includes a coil (128) which provides a magnetic field which acts on the actuator member (130). A speed responsive control unit (112) is effective to vary the strength of the electromagnetic field provided by the coil (128) with variations in vehicle speed to thereby vary the force which is transmitted through the actuator member (130) to the force transmitting assembly (114) as a function of variations in vehicle speed.

Power steering system

A connector assembly (76) connects a power steering fluid reservoir (18) on a vehicle (10) with a bulk holding tank (44) for power steering fluid (46). Upon initiation of the operation of a vehicle engine (16), a control valve (56) is opened to enable power steering fluid (46) to flow from the bulk holding tank (44) through the connector assembly (76) into the reservoir. Operation of a power steering pump (14) on the vehicle (10) causes power steering fluid to flow from the reservoir (18) through the power steering pump (14) and reservoir (18) to the bulk holding tank through return conduits (22, 110, and 78). Air is entrained in the flow of fluid in the return conduits (22, 110 and 78). A vacuum pump (86) is advantageously connected with the bulk holding tank (44) to promote removal of air from the power steering fluid (46) returned to the bulk holding tank.

Filling a vehicle power steering system

A power steering control valve (10) includes inner and outer valve members (30 and 32) which are rotatable relative to each other to control fluid flow to and from a power steering motor. A spring assembly (50) interconnects the inner and outer valve members (30 and 32). The spring assembly (50) includes a torsion bar (64) and a body (66) of viscoelastic material. A housing (68) encloses the body (66) of viscoelastic material and a portion of the torsion bar. The body (66) of viscoelastic material is bonded to an inner side surface (88) of the housing (68) and to an outer side surface (82) of the torsion bar (64). The body (66) of viscoelastic material damps vibratory movement between the inner and outer valve members (30 and 32).

A vehicle steering system (10, 190, 290) includes inner and outer coaxial valve members (40, 42) which are rotatable relative to each other to port fluid to a vehicle power steering motor (30). A plurality of rocker arms (122, 302) are pivotally connected to the inner valve member (40). Each rocker arm (122, 302) is pivotal relative to the inner valve member (40). Each rocker arm (122, 302) engages a recess (132) in the outer valve member (42). Upon relative rotation between the inner and outer valve members (40, 42), the rocker arms (122, 302) pivot relative to the inner valve member (40). Force is applied to each of the rocker arms (122, 302) to resist pivoting of the rocker arms (122, 302) and relative rotation between the inner and outer valve members (40, 42). In one embodiment, a plurality of pistons (222) are disposed in chambers (220) formed in the outer valve member (42). The pistons (222) are exposed to a fluid pressure which varies as a function of vehicle speed. The pistons (222) are effective to vary the force applied against the rocker arms (122) and the resistance to relative rotation between the valve members (40, 42) as a function of vehicle speed.

A steering system for a vehicle includes a hydraulic control valve with first and second coaxial valve members rotatable relative to each other to selectively port pressurized fluid to a vehicle power steering motor. The first valve member is connected to and rotatable with an input shaft. The second valve member is connected to and rotatable with an output member. The second valve member is axially movable relative to the first valve member between first and second positions. The input shaft and the output member are directly interconnected by the second valve member and rotatable together to effect manual steering of the vehicle when the second valve member is in its first axial position. The input shaft is rotatable relative to the output member to effect power assisted steering of the vehicle when the second valve member is in its second axial position. The second valve member is moved from its first position to its second position when the velocity of the vehicle is below a predetermined value.

A power steering control valve includes relatively rotatable inner and outer valve members. A power steering resistance control system resists relative rotation between the inner and outer valve members with a force which varies as a function of variations in vehicle speed. The power steering resistance control system includes a force transmitting member which rotates with the outer valve member and moves axially relative to the inner and outer valve members. Fluid pressure is applied against the force transmitting member urging it in a first direction along the axis of rotation of the valve members. Fluid pressure is also applied against the opposite side of the force transmitting member to urge it in the opposite direction along the axis of rotation of the valve members. A speed responsive control valve, connected with a fluid return conduit for the power steering valve is operable to vary the fluid pressure applied against the opposite side of the force transmitting member as a function of variations in vehicle speed. At relatively low vehicle speeds, the fluid pressure force applied against the opposite of the force transmitting member is relatively large and it is easy to actuate the steering control valve. As vehicle speed increases, the fluid pressure force applied against the force transmitting member decreases and the resistance to actuation of the steering control valve increases.

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St. Clair Shores, MI, United States of America

Henry C Sangret