Advics Co., Ltd.

Nok Corporation

Aisin Seiki Kabushiki Kaisha

Tomoo Ogura

Shinya Nakaoka

Kuniaki Miyake

Eiji Mizutani

Satoshi Kawasumi

Tomonari Saito

Kenji Sasaki

Tatsuhiro Arikawa

Takeshi Watanabe

Yoji Inoue

Yuzuru Sugiura

Katsuhiro Mita

Hiroyuki Nikamoto

Takashi Ota

Noriyuki Hosoi

Taisuke Yamada

To restrain abnormal deformation of a bellows due to a pressure difference between the inside and outside thereof, an outside gas type accumulator includes a pressure difference regulation mechanism () having a movable plate () supported by a coil spring () on the oil port () side of a bellows cap (), the plate () moves together with the cap () in a state of being supported by the spring (), during normal operation, the plate () moves together with the cap () to be brought into contact with a seal () at zero-down time, and the plate () keeps contact with the seal () and the cap () moves to a position where liquid pressure and gas pressure balances while compressing the spring () when the liquid and the charged gas expand thermally.

Accumulator

To prevent abnormal deformation of a bellows, an accumulator has a regulation mechanism for reducing a pressure difference generated when liquid sealed in a liquid chamber and charged gas are thermally expanded at a zero-down time, a seal plate is arranged in an inner peripheral side of a bellows floating end, an elastically deformable thin plate is bonded to the seal plate, an outer peripheral portion of the thin plate is bonded to the bellows floating end, the seal plate is away from a seal at a time of a steady operation, the seal plate contacts with the seal at a zero-down time, and the thin plate is elastically deformed to make liquid pressure balance with gas pressure while the seal plate being kept in contact with the seal when the liquid and gas are thermally expanded.

To prevent plastic deformation of a bellows due to a pressure difference between inner and outer sides of the bellows in an outside gas type or inside gas type accumulator, a disc-like gasket is held in a floatable state to a surface close to a stay in a bellows cap by a gasket holder, so that, the disc-like gasket moves together with the bellows cap at a steady operation time, the disc-like gasket moves together with the bellows cap to contact with an end surface portion of the stay, thereby closing the liquid chamber at a zero-down time, and the bellow cap moves toward a position where liquid pressure and gas pressure balance while the disc-like gasket keeps contacting with the stay due to a difference of pressure receiving areas in both the surfaces when the liquid in the liquid chamber is thermally expanded at a zero-down time.

A master cylinder apparatus is provided with a master cylinder and a booster. The booster comprises a booster shell whose interior is divided into a variable and constant pressure chambers. The master cylinder comprises a master piston inserted in a cylinder body. The cylinder body includes an installation flange to which the booster shell is attached. When the brake pedal is operated, a pull mechanism operates a control valve to communicate the variable-pressure chamber with atmosphere. The master piston is moved by an output member of the booster to generate a fluid pressure in the master cylinder that is delivered to wheel cylinders. The installation flange of the cylinder body can be attached to a dashboard so that the booster shell is disposed in the passenger room or the engine room, with the cylinder body protruding into the other room.

Master cylinder apparatus

A brake booster device for use in a brake system of vehicles is provided with a partition member dividing the interior of the booster shell into front and rear chambers and a piston movable bodily with the partition member within the booster shell. A control valve body is carried on the piston to move toward and away from the rear surface of the piston through a predetermined amount. An air valve member is received within the piston for relative movement thereto and is urged by a compression spring to be moved rearwardly. When the brake pedal is stepped on, the air valve member is forwardly moved by an input rod relative to the piston, whereby the control valve member leads the atmospheric pressure to the rear chamber thereby to move the partition member and the piston forwardly from a home position. When the brake pedal is released, on the contrary, the control valve leads a negative pressure from the front chamber to the rear chamber thereby to permit the partition member and the piston to move rearwardly to the home position by the force of a return spring. The movement of the piston operates a master cylinder through an output rod to generate braking power.

Brake booster device

A vehicle brake booster apparatus includes a housing and a power piston positioned within the interior of the housing to divide the interior into a first pressure chamber and a second pressure chamber, with the power piston being movable in response to a pressure difference between the second pressure chamber and the first pressure chamber. An axially movable input rod extends outwardly from the power piston and is adapted to be operatively connected to a brake pedal. An axially movable output rod extends outwardly from the housing and is adapted to be operatively connected to a master cylinder. An axially movable valve plunger is mounted within the power piston and is operatively connected to the input rod. A control valve is disposed within the power piston and controls the pressure difference between the first pressure chamber and the second pressure chamber. A reaction device is also provided between the housing and the input rod for applying the reaction force produced by the master cylinder to the input rod.

Growing community of inventors

Kariya, Japan

Tomoo Ogura