| 摘要 |
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. The pressurized fluid in the second chamber acts on the piston and provides a power assist to aid in the development of the brake pressure during a brake application. When an operator turns the steering wheel of the vehicle, rotary torque is transmitted through an input shaft to a torsion member connected to a pinion which engages a rack in the steering system. Rotation of the input shaft causes a restriction in the flow of the pressurized fluid from the housing to a piston attached to the rack in the steering gear. The restricted flow causes a pressure differential to be created across the piston to provide a power assist in moving the rack. The movement of the rack is transmitted to rotate the spool valve to eliminate the restrictive flow condition and the pressure differential so that the rack is maintained in a position corresponding to the position of the vehicle steering wheel. |
