Abstract: A brake pressure control unit of vehicle load responsive type is disposed in a brake pressure line extending from a master cylinder to wheel brake cylinders and composed of a P-valve, a load-sensing lever abutting on a plunger of the P-valve, a secondary spring disposed between the bracket secured to the P-valve and the free end of the lever, and a primary spring disposed between the other free end of the lever and a lower end of a rod which is swingably held on the other free end of the lever. The brake pressure control unit is preassembled as one unit before it is installed in the vehicle as it is. The direction of the biasing force of the secondary spring is the same as that of the primary spring.

Abstract: A brake fluid pressure controller is interposed between a master cylinder and the rear wheel cylinders. The controller comprises a housing having an inlet, an outlet and a chamber which provides communication between the inlet and the outlet. An annular sealing member is disposed around a piston in the chamber with a clearance left therebetween. The sealing member has an inner perimeter defining a valve seat and an outer perimeter defining a flexible lip portion which is in contact with the internal wall of the chamber. When a valve head of the piston sits on the valve seat of the sealing member, the inner perimeter of the valve seat cuts off the communication between the inlet and the outlet. Meanwhile, the outer perimeter permits a communication from the outlet to the inlet but shuts off a communication from the inlet to the outlet. A spring urges the piston to a direction in which the valve head separates from the valve seat.

Abstract: A brake pressure control system for a wheeled vehicle includes a swingable lever pivotally mounted at a first end portion thereof to a sprung mass of the vehicle such as a body frame, a first tension coil spring connected at a first end thereof to the sprung mass and at a second end thereof to a second end portion of the swingable lever to bias the lever toward the sprung mass, a second tension coil spring connected at a first end thereof to an unsprung mass of the vehicle such as a wheel axle and at a second end thereof to the second end portion of the swingable lever to bias the lever against the biasing force of the first spring, a bushing rotatably mounted on the second end portion of the swingable lever, the bushing being formed with a first support portion for retaining the second end of the first spring and a second support portion for retaining the second end of the second spring, and a modulator valve secured to the sprung mass and incorporated in a hydraulic connection between a master cylinder and

Abstract: A hydraulic pressure control valve for use with two independent rear braking systems, for transmitting braking hydraulic pressure to wheel cylinders in two rear wheels of a vehicle through two independent pipings. The control valve has a pair of valves, a pair of parallel pistons disposed in a single housing, and an actuating mechanism for displacing the pistons according to vehicle load. The actuating mechanism consists of a lever capable of rocking in a plane, a spring member for applying a force corresponding to the vehicle load to the rocking end of the lever, a support pin having both ends fitted in two grooves that extend parallel to the axes of the pistons and are equidistant from these axes, an equalizer which comes into abutment with one end of each piston at its either end. The equalizer is supported on the pin such that it can rock about its recessed center.