Abstract: The present invention relates to the gear configuration between a pinion and a rack. The pinion forms a plurality of teeth which are received in respective grooves on the rack. The teeth each define a pair of flanks which oppose a pair of surfaces within the groove and the flanks and surfaces substantially define circular arcs. The radius of curvature of the circular arc for the surfaces is slightly larger than the radius of curvature of the circular arc for the flanks. A separating force is generated between the pinion and the rack when rotation of the pinion imparts transverse movement to the rack and the circular arcs of matching surfaces and flanks cooperate to substantially eliminate the separating forces after slight separation between the pinion and the rack.

Abstract: A flow divider valve cooperates with a housing to control flow between an input port, a first output port and a second output port. The valve defines a first land and a second land and is movable within the housing to a first position wherein flow is decreased to the first output port and increased to the second output port, and to a second position wherein flow is decreased to the second output port and increased to the first output port. Movement of the valve to the first and second positions is controlled by pressure within the first and second output ports. A passage on the valve communicates flow to both sides of the valve.

Abstract: An hydro-mechanical torque amplifier such as a power steering unit for road vehicles. In the prior art, torque amplifying hydraulic pressure was applied to the linear part of a ball-screw geared to the output shaft such that all power went through meshing gear teeth, necessitating robust construction thereof. In the present invention, torque amplifying hydraulic pressure is applied to a vane motor on the output shaft such that hydraulic power does not pass through gear teeth, enabling a lighter and less costly construction.

Abstract: A power steering device includes an input member, a sleeve and an output member such that rotation of the input member relative to the output member communicates pressurized fluid through the sleeve to provide a power assist during steering. At least one pin is disposed between the input member and the sleeve to define fluid paths through the device and limited rotation between the input member and the sleeve increases the fluid flow in one of the fluid paths and decreases the fluid flow in the other of the fluid paths. A groove in the sleeve and a slot in the input member receive the one pin. The one pin is normally maintained in spaced relation to the input member by means of an axial cutout in the slot. In order to control pressure buildup due to fluid flow between the pin and the input member slot, the pin or the input member are provided with axial recesses at the location where the pin is engageable with the input member slot when the input member is rotated relative to the sleeve.

Abstract: A steering system includes a sensor device which is responsive to excessive steering effort to actuate a power assist for steering. A housing rotatably receives an input member and an output member which are rotatable relative to each other when the steering effort is excessive. The housing includes an inlet communicating with a source of pressurized air and an outlet opening to atmosphere. The input member and output cooperate to define a passage communicating the inlet with the outlet such that limited rotation between the input member and output member varies the communication of pressurized air through the passage. When the communication of pressurized air through the passage is varied, a relay valve in communication with the inlet is operable to actuate the power assist.