Nissin Kogyo Co., Ltd.

Honda Motor Co., Ltd.

Autoliv Nissin Brake Systems Japan Co., Ltd.

Kazuhiro Tagata

Kenji Suzuki

Yasushi Aoki

Isao Matsuno

Koji Sakai

Kazuaki Murayama

Jiro Suzuki

Motoyasu Nakamura

Takaaki Ohnishi

Yoshiyuki Takamatsu

Hiroshi Nakano

Nobuyuki Kobayashi

Takaomi Shirase

Tetsuo Sasaki

Nobutake Hyodo

Hideki Hidume

Provided is a piston push rod assembly which can prevent discomfort from being imparted during the operation of a brake pedal by a driver. A piston push rod assembly, wherein: a second piston is provided with a piston slide section which is housed in a cylinder and which slides relative to the cylinder, and a connection tube section which is connected to a push rod; the piston slide section is covered by metal plating; the connection tube section has a non-plated section; and the second piston and the push rod are connected by the caulking of the connection tube section when the push rod has been inserted inside the connection tube section.

Piston push rod assembly, master cylinder, and manufacturing method for piston push rod assembly

Provided is a stroke simulator capable of suppressing occurrence of inclination of a piston with respect to a sliding surface formed in a cylinder. The stroke simulator includes a simulator piston which is displaced by sliding on a sliding surface formed in a first cylinder, and a first return spring which is housed in the first cylinder and applies, to the simulator piston, a reaction force which is generated by an elastic deformation of the spring under a pressing force due to a displacement of the simulator piston, and generates the reaction force which is applied to the simulator piston as a brake reaction force for a brake operating element. The stroke simulator is characterized in that a cup seal for sealing a gap formed between the sliding surface and the simulator piston is mounted in the middle in the axial direction of the sliding surface.

Stroke simulator

A cylinder device includes a regulation mechanism that regulates separation distance between a front piston and a rear piston. A spring seat member of the regulation mechanism includes a spring reception part that projects toward a retainer side to receive a rear end of a spring, a cup seal holding part that projects on an opposite side from the retainer to hold a cup seal arranged on the rear piston, and a projection part that projects on the opposite side from the retainer. The projection part becomes abuttable on the retainer by a stroke of the rear piston if the spring reception part and the cup seal holding part are installed reversely-oriented on the rear piston.

Cylinder device and vehicle brake system

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 normally opened solenoid valve includes: a coil; a fixed core; a movable core; a valve seat located at one of openings of a through hole formed in the fixed core; and a valve body inserted into the through hole. The valve body includes: a shaft part inserted into the through hole and pressed by the movable core; a valve part seated on or separated from the valve seat; and a connection part configured to connect the shaft part with the valve part. The connection part includes a conical portion increased in diameter toward the shaft part from the valve part. A plurality of reduced thickness portions, each having a concave shape as viewed in an axial direction, are formed in the conical portion. The reduced thickness portions are located at equal intervals in a circumferential direction of the conical portion.

Normally opened solenoid valve

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 vehicle braking system having a hydraulic booster which applies output hydraulic pressure of a hydraulic power source to a boosted hydraulic pressure chamber after regulating the output hydraulic pressure as a control piston balances a reaction force generated by hydraulic pressure of the boosted hydraulic pressure chamber with brake operating input. The boosted hydraulic pressure chamber faces a rear face of a master piston of a master cylinder; and a brake stroke simulator installed between a brake operating member and the control piston. The hydraulic booster includes a backup piston slidably housed in a casing with its front face turned to the boosted hydraulic pressure chamber and which can directly push the master piston in response to operation of the brake operating member when the hydraulic pressure of the boosted hydraulic pressure chamber decreases. The control piston and the brake stroke simulator are contained in the backup piston.

Vehicle braking system

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.

In a vehicle braking system, a backup piston pushes a master piston directly from behind when hydraulic pressure of a boosted hydraulic pressure chamber decreases. The backup piston has a piston body which is slidably fitted in a casing, and a pusher which is slidably fitted in the casing with a seal diameter smaller than seal diameters of the master piston and the piston body and which extends to the front end of the piston body, to push the master piston from behind. An annular input chamber communicated with a hydraulic power source is formed between the backup piston and the casing. When the pusher pushes the master piston forward, amount of volume increased in the boosted hydraulic pressure chamber is set to be substantially equal to amount of volume decreased in the input chamber. Thus, it is possible to avoid increase in the hydraulic pressure of the boosted hydraulic pressure chamber during forward movement of the backup piston, using a simple configuration with a reduced number of parts.

A hydraulic controller includes: a pair of liquid chambers; and an on-off valve capable of opening and closing a flow channel on the side of the liquid chamber with a higher hydraulic pressure out of the pair of liquid chambers. The flow channel can provide communication between the pair of liquid chambers. A baffling device is provided in the liquid chamber with a lower hydraulic pressure, to baffle hydraulic fluid flowing from the liquid chamber with the higher hydraulic pressure. Thus, it is possible to reduce operating noise resulting from operation of the on-off valves.

Hydraulic controller

A vehicle braking system includes: a hydraulic booster which applies output hydraulic pressure of a hydraulic power source to a boosted hydraulic pressure chamber after regulating the output hydraulic pressure as a control piston operates to balance reaction force generated by hydraulic pressure of the boosted hydraulic pressure chamber with brake operating input; and a brake stroke simulator installed between the brake operating member and the control piston in order for a driver to feel operating strokes of the brake operating member. The brake stroke simulator has: an input member axially slidably housed in the control piston of a cylindrical shape and linked to the brake operating member; and an elastic body interposed between the input member and the control piston. The elastic body is formed into a tubular shape so as to come into resilient contact with an inner circumference of the control piston by expanding its diameter under the action of axial compressive force generated by forward movement of the input member. Consequently, the brake stroke simulator allows large hysteresis width in relationship between brake operating stroke and operating load.

A simulator piston is slidably fitted in a control piston to form a stroke liquid chamber between itself and an end wall of a control piston. A port which is closed at a forward limit of the control piston with respect to a backup piston is provided in the end wall of the control piston. A first reaction piston which constantly abuts against the end wall of the control piston and a second reaction piston which abuts against the end wall of the control piston when the control piston advances toward the backup piston through a predetermined travel distance or more, are relatively slidably mounted on the backup piston so that hydraulic pressure of the boosted hydraulic pressure chamber acts on their front ends. Thus, it is possible to curb increase in a stroke and reaction of a brake operating member which would be invalidated by a brake stroke simulator when a hydraulic power source fails, and avoid insufficient strokes of the brake operating member even if spikes are inputted.

Growing community of inventors

Nagano, Japan

Kazuhiro Tagata