Jidosha Kiki Co., Ltd.

Akihiro Kamiyoshihara

Mutsuro Yamakoshi

Kunio Yanagi

The hydraulic brake pressure control valve is provided including a valve casing mounted on a master cylinder of a hydraulic brake system. A valve piston is provided with a stepped configuration with an enlarged diameter portion and a reduced diameter portion. The valve piston is mounted slidably and longitudinally along the longitudinal bore of the valve casing. The valve piston is normally urged into a non-operating position and is shiftable longitudinally in an opposite direction from the non-operating position under the effect of a difference in the cross-sectional areas of the enlarged and reduced diameter portions, upon which hydraulic brake fluid pressure acts. The stepped valve piston is defined with a brake fluid passage extending longitudinally therein providing communication between brake fluid passages adjacent the reduced diameter portion and the enlarged diameter portion of the stepped valve piston. A fluid valve member is disposed in the fluid passage and is adapted to hold the fluid passage in an open position when the stepped valve piston is in a non-operating position and to cause the fluid valve to be opened and closed when the stepped valve piston operates in a valving manner. An arrangement is provided such that when the fluid valve is brought to either an opened or a closed position an outer wall surface associated with the valve member abuts an inner wall surface of the stepped valve piston.

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Higashimatsuyama, Japan

Akihiro Kamiyoshihara