Nissin Kogyo Co., Ltd.

Honda Motor Co., Ltd.

Autoliv Nissin Brake Systems Japan Co., Ltd.

Koji Sakai

Kazuhiro Tagata

Kenji Suzuki

Yasushi Aoki

Jiro Suzuki

Hiroshi Nakano

Takaomi Shirase

A pressure regulating valve unitis configured to be electrically driven according to a detection value of a detection unitadapted to detect an amount of brake application effort made by a brake operation memberso as to switch states of the vehicle brake apparatus between a state where a boosted hydraulic pressure chamberis made to communicate with a hydraulic pressure generating sourcewhile a communication between the boosted hydraulic pressure chamberand a reservoir R is interrupted, a state where the communication between the boosted pressure chamberand the hydraulic pressure generating sourceis interrupted while the boosted pressure chamberis made to communicate with the reservoir R, and a state where the boosted hydraulic pressure chamberis disconnected from both the hydraulic pressure generating sourceand the reservoir R.

Vehicle brake apparatus

A pressure regulating valve unit is configured to regulate the output hydraulic pressure of a hydraulic pressure generating source through electrical control for application to a boosted hydraulic pressure chamber, and a release valve is interposed between the boosted hydraulic pressure chamber and a reservoir which is adapted to the hydraulic pressure in the boosted hydraulic pressure chamber to the reservoir side when the pressure regulating valve unit fails.

A fluid pressure booster includes: a control piston in which brake operation input acts in an advancing direction, and reaction based on fluid pressure of a booster fluid pressure generation chamber that generates fluid pressure for actuating a master piston acts in a retracting direction; a pressure increasing valve provided between the booster fluid pressure generation chamber and a fluid pressure generation source so as to open at the time of advance of the control piston and close at the time of retraction of the control piston; and a pressure reducing valve provided between a release chamber and the booster fluid pressure generation chamber so as to close at the time of the advance of the control piston and open at the time of the retraction of the control piston. The pressure increasing valve includes first valve means and second valve means that sequentially open according to an increase in the brake operation input, and a seal diameter of the second valve means is larger than that of the first valve means. Thus, it is possible to enhance initial response of the pressure increasing valve, and also enhance response of the pressure increasing valve when a brake operation member is strongly operated.

Fluid pressure booster

A reservoir chamber, which communicates with a vent passageprovided in an electric motor, is formed between a motor casingof the electric motorand a bodyin which a drain portA, which communicates with the reservoir chamber, is provided with its external open end oriented downwardly, and a capacity of the reservoir chamberbelow the vent passageis set to become larger than a sum of a cooling contraction amount of air in the electric motorand the reservoir chamberwhich contracts in response to cooling by water covering the pump apparatus which has been warmed up under an operating environment and a pressurizing compression amount of air in the electric motorand the reservoir chamberwhich is compressed by a water pressure applied from the drain, portA when the pump apparatus is submerged.

Plunger pump apparatus

A vehicle braking device includes a stroke simulator provided between a control piston of a fluid pressure booster and a brake operation member, wherein the control piston has an inner peripheral surface partially including a tapered surface with a decreasing diameter toward the front. The stroke simulator includes an input member housed in the control piston slidably in an axial direction backward of the tapered surface and connected to the brake operation member, and an elastic body interposed between the input member and the control piston and housed in the control piston. The elastic body has a cylindrical shape so as to be elastically deformed according to an action of an axial compressive force along with an advancing operation of the input member, and prevented from being deformed sequentially from the front by restraint with the tapered surface according to an increase in the axial compressive force. This provides a nonlinear characteristic in a relationship between a brake operation stroke and an operation load, and efficiently provides a hysteresis characteristic.

Vehicle braking device

There is provided a vehicle braking device in which a front outer periphery of a backup piston that can directly press a master piston from behind when output fluid pressure from a fluid pressure generation source is reduced is fluid-tightly and slidably fitted to a short cylindrical separator, a sleeve forming an annular channel between itself and an outer periphery of the backup piston is placed backward of the separator, and annular seal members for sealing front and rear sides of the annular passage are mounted between the separator and the backup piston, and between the sleeve and the backup piston. The seal member for sealing a front side of the annular passage is mounted to an inner periphery of the separator so as to come into repulsive contact with the outer periphery of the backup piston. The seal member for sealing a rear side of the annular passage is mounted to the outer periphery of the backup piston so as to come into repulsive contact with an inner periphery of the sleeve. Thus, it is possible to reduce an axial size of the vehicle braking device.

Growing community of inventors

Nagano, Japan

Koji Sakai