Abstract: A brake booster includes a housing with at least one piston therein to separate a pressure chamber from a work chamber. A valve assembly carried by the one piston is operable to communicate fluid pressure to the work chamber to move the piston. An input assembly is movable to control operation of the valve assembly.

Abstract: A closed-center hydraulic servo apparatus (10) includes a closed-center valve device (112) which is coupled to an input member (60) to control the communication of fluid among a fluid pressure source (12,14), a fluid reservoir (36), and a fluid pressure responsive device (a vehicle brake) (16) in response to movement of the input member (60). The coupling (158, 160) between the closed-center valve device (112) and the input member (60) provides a movement ratio therebetween which is greater than unity. As a result, the inherent deadband (D) of the closed-center valve device (112) is reduced by the inverse of the movement ratio to a level (d) which is sensible to an operator at the input member (60).

Abstract: A variable displacement rotary pump includes a tiltable cam plate which varies the pump displacement as a function of the fluid pressure in a control chamber. The pump pumps fluid to a fluid motor via an orifice in an outlet passage. A spool valve meters fluid to the control chamber in response to the differential pressure across the orifice. Pressure on one side of the orifice acts upon the spool valve in a feedback chamber remote from the outlet passage. The orifice is defined by an annular space between the wall of the outlet passage and neck portion of the spool valve. A feedback passage in the spool valve communicates fluid pressure from the one side of the orifice to the feedback chamber. A leakage flow path extends through a bearing to provide for automatic bearing lubrication.

Abstract: A rotary valve for use in a steering control of an integrated brake and steering system. The rotary valve has a pinion with a first end fixed to a housing and a second end to which a lever arrangement is attached. The pinion has a series of grooves located on its surface and whenever the lever arrangement is moved, the grooves control the flow of fluid to a piston. Thereafter, movement of the piston by the fluid creates a rotary torque that is supplied to a steering gear to aid in the operation of the steering system.

Abstract: An integrated control mechanism for regulating the communication of pressurized fluid from a source to a brake system and a steering system of a vehicle in response to independent operator brake and steering signals. The integrated control mechanism has a housing with a bore therein connected to a single source of fluid under pressure. A rotary valve located in the bore is rotated in response to an operator steering signal to control the communication of the pressurized fluid to the steering system from the bore and thereby provide a power assist in steering the vehicle. A spool valve, concentrically located in said bore with respect to said rotary valve, linearly moves in response to an operator braking signal to control the communication of the pressurized fluid from the bore to the brake system and thereby provide a power assist in effecting a brake application.

Abstract: A control mechanism through which pressurized fluid from a source is communicated into a brake system and a steering system in response to independent operator brake and steering signals. The control mechanism has a housing with a first bore and a second bore therein. A piston located in the first bore separates a first chamber and a second chamber. A spool valve located in the second bore separates a brake pressure chamber created therein from a series of lands that control the flow of the pressurized fluid through the housing. When an operator effects a brake application, the piston moves in the first bore and creates a brake pressure in the first chamber. The brake pressure which is communicated to the brake pressure chamber in the second bore linearly moves the spool valve and allows pressurized fluid to be communicated to the second chamber in the first bore.

Abstract: A master cylinder assembly for simultaneously actuating the front and rear wheel brakes of a vehicle. The master cylinder assembly includes a housing having a bore therein with a first piston separated from a second piston by a first spring to establish a first pressurizing chamber while a second spring separates the second piston from the bottom of the bore to establish a second pressurizing chamber. The first and second piston each have a compensating passage therethrough for communicating fluid from a reservoir into the first and second pressurizing chamber, respectively. A first valve seat located in the first pressurizing chamber is connected to a second valve seat in the second pressurizing chamber. A valve return spring in the second pressurizing chamber urges the first and second valve seats toward the first and second pistons.

Abstract: A master cylinder assembly for simultaneously actuating the front and rear wheel brakes of a vehicle. The master cylinder assembly includes a housing having a bore therein with a first piston separated from a second piston by a first spring to establish a first pressurizing chamber while a second spring separates the second piston from the bottom of the bore to establish a second pressurizing chamber.The second piston has a first passage which connects the first pressurizing chamber to a reservoir in the housing and a second passage which connects the second pressurizing chamber to the reservoir. A guide on the second piston is located in a keyway in the housing to prevent the second piston from rotating. A first telescoping sleeve member located on the first piston is aligned with the first passage while a second telescoping member attached to the housing is aligned with the second passage.

Abstract: A brake booster for use in a braking system having a control valve which is responsive to a hydraulic output force created by manually moving a piston in a bore of a master cylinder. The hydraulic output force actuates the control valve which proportionally directs a portion of the fluid output of a pump which supplies a power steering gear with hydraulic fluid, into the bore. This portion of the output of the pump acts on the piston and provides an auxiliary force for moving the piston through which the hydraulic output force is created. When the hydraulic output force of the brake booster reaches a predetermined value, the control valve engages a stop member to limit the diversion of the fluid output from the pump and thereby assure that a minimal quantity of the fluid output is continually available to operate the power steering gear.