Nabco Limited

Hiroshi Okuma

A master cylinder includes a cylinder main body forming a piston mount space and a piston mounted in the cylinder main body. An auxiliary supplying/discharging passage communicating sideways with the piston mount space is provided at a longitudinally middle portion of the cylinder main body. The inner circumferential surface of the cylinder main body and the outer circumferential surface of the piston are shaped such that a communication path communicating a pressure chamber near a supplying/discharging opening and the auxiliary supplying/discharging passage is formed at the outer side of a seal ring mounted on the piston with the piston moved back to a rearmost position most distanced from the supplying/discharging opening. The position of the piston and the pressure in the pressure chamber can be stabilized when the piston is located at a rearmost position from the supplying/discharging opening.

Hydraulic master cylinder

A hollow cylinder has an opening at one end, and a push rod passes through the opening so that a coupling at one end of the push rod is in the cylinder. A piston is reciprocally movably in the cylinder, and a spring urges the piston into contact with the coupling. The opening includes a through groove configured to pass the coupling when the longitudinal axes of the cylinder and the push rod are normal and to prevent the coupling from coming out when the longitudinal axes of the cylinder and the push rod align. An insertion groove in the side surface of the cylinder is continuous with the through groove and is adapted for passing a rod portion in the inserting state.

Growing community of inventors

Tokyo, Japan

Hiroshi Okuma