Abstract: In the assembly of a master cylinder and an oil-hydraulic booster connected to the rear thereof, the master cylinder has an axial bore consisting of a forward, small-diameter bore section and a rearward, large-diameter bore section and the master cylinder piston in the master cylinder includes a small-diameter section slidably fitted in the small-diameter bore section of the master cylinder and a large-diameter section slidably fitted in the large-diameter bore section thereof. The forward end portion of the piston in the oil-hydraulic booster is formed smaller in diameter than the large-diameter bore section of the master cylinder and is arranged proximate the large-diameter section of the master cylinder piston in the master cylinder so as to enter the large-diameter bore section of the master cylinder when the booster piston is advanced.

Abstract: In the assembly of a master cylinder and an oil-hydraulic booster connected to the rear thereof, the master cylinder has an axial bore consisting of a forward, small-diameter bore section and a rearward, large-diameter bore section and the master cylinder piston in the master cylinder includes a small-diameter section slidably fitted in the small-diameter bore section of the master cylinder and a large-diameter section slidably fitted in the large-diameter bore section thereof. The forward end portion of the piston in the oil-hydraulic booster is formed smaller in diameter than the large-diameter bore section of the maste cylinder and is arranged proximate the large-diameter section of the master cylinder piston in the master cylinder so as to enter the large-diameter bore section of the master cylinder when the booster piston is advanced.

Abstract: Disclosed is an improved device for controlling hydraulic pressure for braking a vehicle of the type including a pressure reducing valve disposed midway of an oil passage extending between an output port of a master cylinder and a rear wheel brake, said pressure reducing valve being adapted to proportionally reduce hydraulic pressure from the output port and then transmit reduced hydraulic pressure to the rear wheel brake. The improvement consists in that a pneumatic spring incorporated in a suspension system for determining hydraulic pressure at which the pressure reducing valve initiates pressure reducing function in dependence on the weight of cargoes loaded on the vehicle is operatively connected to a valve body of the pressure reducing valve in such a manner as to bias the valve body in the valve opening direction.

Abstract: In a brake oil pressure controlling valve device for vehicles of the type wherein a reducing valve adapted to proportionally reduce output oil pressure from a master cylinder to transmit it to a rear wheel brake and a pressure adjusting spring for urging the reducing valve in the valve opening direction and determining the reduction starting pressure thereof, are interposed in an oil path connecting between an output port of the master cylinder and the rear wheel brake, the disclosed valve device is further provided with: a pressure reducing piston which is normally held by virtue of resilient force of a set spring at its advanced limit position where the reducing valve is made open and which is retreated to close the reducing valve and to reduce oil pressure on the output side of the reducing valve when the resilient force of the set spring is released; a controlling oil pressure chamber supplied with oil pressure from an oil pressure source when a rear wheel is about to come into a locked state; and a contr

Abstract: An improved hydraulic braking pressure control device for a dual braking system including a pair of first and second hydraulic lines extending from a dual type brake master cylinder to the front and rear wheel brakes. The device includes a common housing mounted across the first and second hydraulic lines, and a pair of differential pistons slidably received in the aligned cylinder bores in the housing to respectively define on their opposite sides a first input and a first output hydraulic chamber and a second input and a second output hydraulic chamber, the adjacent input and output chambers being in communication with each other through respective valves which are operated to open and close by a pair of valve actuating pistons slidably fitted in the respective input chambers. A pressure control spring is arranged between the differential pistons to urge them in the direction away from each other.

Abstract: An improved hydraulic pressure control valve device includes a valve housing having first and second inlet ports of the master cylinder, respectively, first and second inlet ports communicated with the left and right rear wheel brakes of the vehicle, respectively, a first control pressure chamber interconnecting the first inlet port and the first outlet port, a second control pressure chamber interconnecting the second inlet port and the second outlet port, and a cylinder bore interconnecting the first and the second outlet ports; a pressure reducing valve adapted to normally open the first control pressure chamber and to open and close the first control pressure chamber as the pressure at the first inlet port exceeds a predetermined level so as to transmit the pressure to the first outlet port while proportionally reducing the pressure; a cut-off valve adapted to normally open the second control pressure chamber in the normal state, a valve rod integrally connected to the reducing valve to operate the cut-of

Abstract: A brake oil-pressure control valve device for vehicles in which operating oil pressure of rear wheel brakes is automatically controlled in accordance with the braking force as required. The device comprises first and second branch oil passages branched from an oil passage connected to a rear wheel brake output port of a master cylinder, a reducing valve interposed between the first branch oil passage and the rear wheel brakes, springs for determining pressure to start reducing action of the reducing valve, a control piston disposed in an oil pressure chamber communicated with the second branch oil passage to normally hold the reducing valve in its open position, and a weight valve disposed within the valve chamber to sense deceleration of the vehicle.