Aisin Seiki Kabushiki Kaisha

Toyota Jidosha Kabushiki Kaisha

Aisin Seiki Kabushiki

Hiromu Kuromitsu

Nobuyasu Nakanishi

Hiroaki Takeuchi

Kazutaka Kuwana

Yoshiharu Adachi

Noboru Noguchi

Tomohiko Hosoda

Seiichi Kojima

Norihito Kambe

Kazuya Watanabe

Michiharu Nishii

Kenji Tozu

Akihito Kusano

Tadashi Terazawa

Hiroshi Toda

Takayuki Itoh

Akira Shirai

Toshihiro Nakano

Takayoshi Tsuzuki

Norio Yamazaki

Takumi Nishimura

Takeshi Nakane

Matsuhisa Tsuruta

Naoki Ohara

Masashi Sawada

Naoyasu Enomoto

Hideaki Iijima

Jun Mihara

Hideharu Hironaka

Masakazu Sugisawa

Yoshiki Noda

Yoshiharu Nishizawa

In a master cylinder for drawing brake fluid from a reservoir through a pressure generating chamber in the master cylinder during fluid pressure control to supply brake pressure to a wheel cylinder, a check valve is provided for securing sufficient suction from the master cylinder. The check valve is operational to communicate the supply chamber and the pressure generating chamber with each other only when the pressure generating chamber is under a negative pressure while the piston is in a non-operating position. The check valve is arranged within the inner portion of the piston and along the axis of the piston.

Master cylinder

The present invention is directed to a hydraulic pressure control system for controlling a hydraulic pressure in each wheel brake cylinder operatively mounted on each wheel of a vehicle, which includes a modulator disposed between a master cylinder and the wheel brake cylinder for introducing thereto and draining therefrom the brake fluid. First and second pump devices are provided for introducing the brake fluid and pressurizing it to discharge the pressurized brake fluid to the wheel brake cylinder through the modulator, respectively. The second pump device has a different suction phase from the suction phase of the first pump device. A changeover valve device is disposed between the master cylinder and the modulator, and adapted to select one of a first operating position for communicating the master cylinder with the modulator and blocking the communication between the master cylinder and the first and second pump devices, and a second operating position for communicating the master cylinder with the first and second pump devices and blocking the communication between the master cylinder and the modulator. First and second check valves are disposed between the changeover valve device and the inlets of the first and second pump devices for allowing the brake fluid to flow from the changeover valve device to the first and second pump devices and blocking the reverse flow. Preferably, the outlets of the first and second pump devices are communicated with a common volume chamber.

Hydraulic pressure control system for a vehicle

A hydraulic braking pressure control device for a hydraulic braking system that includes a wheel brake cylinder operatively connected to a wheel of a vehicle for applying braking force to the cylinder and a master cylinder for generating hydraulic pressure in response to depression of a brake pedal and for supplying the hydraulic pressure to the wheel brake cylinder. In the hydraulic braking pressure control device, a solenoid valve is provided for controlling the hydraulic pressure in the wheel brake cylinder. A pump is connected to the wheel brake cylinder and is disposed in a pump body. The pump is driven by a motor which is disposed in a motor casing. The motor casing is connected to a face of the pump body and the solenoid valve is disposed in the motor casing.

Hydraulic braking pressure control device

A plunger pump includes a piston which is driven for reciprocatory motion and associated with a check valve. A space within a cylinder is partitioned by a piston 1p into a first space A which communicates with a discharge port 1ep and a second space B which communicates with a suction port 1ip. To reduce the peak value of a fluctuation in the suction pressure, a third port 2ip communicating with the first space A is added, and the suction port 1ip and the third port 2ip are connected in common to a suction line Pin through check valves 20 and 19, respectively. The first space A has a diameter greater than the diameter of the piston while the second space B has a diameter which is comparable to the diameter of the piston and hence is less than that of the first space A. On the forward stroke of the piston, a braking liquid is drawn into the second space from the suction line Pin. On the return stroke of the piston, a braking liquid is drawn into the first space A from the suction line Pin, and a braking liquid flows from the second space B to the first space A through a center opening in the piston. On the forward stroke of the piston, the braking liquid in the first space A is discharged through a discharge port 1ep. The suction of the braking liquid into the cylinder from the suction line Pin is dispersed between the forward and the return stroke, thus suppressing a peak in the fluctuation in the suction pressure.

Reciprocating pump for generating fluid pressure

A wheel brake pressure controlling system includes a brake pressure operating circuit for selectively supplying to a wheel brake a primary pressure generated by a vacuum booster in response to the depression of a brake pedal and a secondary pressure generated by a hydraulic pressure pump which is driven by an electric motor, a microcomputer for estimating a turning of vehicle, determining if a turning of the vehicle is in a over- or under-steer region, and for determining a wheel brake, the pressure of which is to be intensified if the turning of the vehicle lies in the over- or under-steer region, and an output controller for supplying the secondary pressure to the wheel brake which has been thus determined, through the brake pressure operating circuit. The microcomputer determines if the turning of a vehicle occurs in a reference region located outside the over- or under-steer region, and whenever the turning of the vehicle occurs in the reference region, drives the second source of pressure for generating the secondary pressure, determines a wheel brake which is to be intensified, and automatically intensifies the wheel brake.

Wheel brake pressure controlling system in which vehicle operating

An electromagnetic valve device includes a valve body having a first fluid chamber, and inlet and outlet passages fluidly communicating with the first fluid chamber. In a first fluid chamber, a first movable member is slidably received within a stationary sleeve to define a second fluid chamber within the sleeve. The second fluid chamber is in continuous fluid communication with the first fluid chamber and is in fluid communication with the inlet passage. The first member has a first valve for selectively interrupting fluid communication between the inlet passage and the first fluid chamber, and is urged by a return spring into a first position to effect fluid communication between the first fluid chamber and the inlet passage. A second movable member operatively connected to an electromagnet has a second valve for selectively interrupting the fluid communication between the inlet passage and the second fluid chamber. The second member is urged by a return spring into a non-energized position in which fluid communication between the second fluid chamber and the inlet fluid passage is interrupted when the first member is positioned in the first position. When the electromagnet is energized, the second member moves to an energized position and the first member is moved by the second member into a second position to interrupt fluid communication between the inlet passage and the first fluid chamber. A pressure differential between the inlet and outlet passages greater than a predetermined pressure differential holds the first member in the second position so that restricted fluid communication occurs between the inlet and outlet passages when the electromagnet is de-energized.

Electromagnetic valve device

A hydraulic braking pressure control apparatus adapted to a vehicle braking system for a set of wheel brake cylinders, which includes an electric operated valve assembly provided to control hydraulic braking fluid under pressure supplied from a master cylinder to the wheel brake cylinders and an electrically operated fluid pump cooperable with the valve assembly to recirculate hydraulic fluid from each of the wheel brake cylinders into a fluid reservoir of the master cylinder when a set of road wheels of the vehicle tend to be locked in braking operation. The valve assembly is constructed to restrict recirculation of hydraulic fluid from either one of the wheel brake cylinders when the hydraulic pressure in the other wheel brake cylinder is decreased by operation of the fluid pump.

Hydraulic braking pressure control apparatus for automotive vehicle

In a hydraulic brake system for a vehicle, the brake fluid in a first wheel brake and the brake fluid in a second wheel brake which are hydraulically connected to a pressure generating chamber of a master cylinder are individually caused to flow into a low back pressure reservoir with the aid of an electromagnetic change-over valve and first and second electromagnetic cut-off valves; and with a pump driven by an electric motor, the brake fluid flowing in the low back pressure reservoir in the above-described manner is caused to flow through a first check valve and a first orifice to the first wheel brake, and through a second check valve and a second orifice to the second wheel brake. With the pump operated, the first and second electromagnetic cut-off valves are individually operated, so that the first and second wheel brakes are individually decreased or reincreased in hydraulic pressure. For traction control, electromagnetic change-over valves provided in bypass passages are operated. Thus, with the system, anti-lock control and traction control can be achieved, and, even when the valves added for traction control become out of order, brake fluid can be supplied to or drawn from the wheel brakes as required.

Hydraulic brake system for vehicle

A disk brake assembly includes a disk rotor, a mounting member secured to a vehicle body and having a pair of opposed arms positioned at opposite sides of the disk rotor, respectively, a pair of confronting pads arranged on the arms, respectively, a caliper slidably supported on the mounting member so as to be movable in an axial direction generally parallel to an axis of the disk rotor, the caliper having a piston portion and a reaction portion disposed on opposite sides of the disk rotor and arranged to press the pads against opposite surfaces of the disk rotor for generating a braking force therebetween, a plate secured to one of the arms so as to be deformed upon generation of the braking force along a direction thereof, and a detecting device serving for measuring a deformation of the plate as a braking force and converting the deformation into an electric signal.

Disk brake assembly

An antiskid apparatus for an automotive vehicle including a cut-off valve having an inlet side to which a master cylinder is connected and an outlet side to which a wheel cylinder is connected for cutting off a supply of pressurized oil from the master cylinder to the wheel cylinder when an antiskid operation is performed, and a pump connected between the cut-off valve and wheel cylinder for supplying pressurized oil to the wheel cylinder when an antiskid operation is performed. The master cylinder and wheel cylinder being brought into slight communication via a microgroove in the spool of the cut-off valve when the spool is at a closed position. Pedal shock at antiskid operation is alleviated.

Antiskid apparatus

An antiskid apparatus including a changeover valve disposed in a line connecting a master cylinder and a wheel brake, the changeover valve being changed over between a first mode for cutting off the wheel brake from the master cylinder and connecting the wheel brake to a reservoir, and a second mode for alternately connecting the wheel brake to a pump and the reservoir when an antiskid operation is performed, a pressure increase control valve connected between the pump and changeover valve with wheel brake pressure serving as a control signal pressure, and a pressure decrease control valve connected between the wheel brake and reservoir with wheel brake pressure serving as a control signal pressure. The pressure increase control valve decreases an amount of pressurized oil flow from the pump to the wheel brake when wheel brake pressure decreases and increases the amount of pressurized oil flow from the pump when wheel brake pressure increases. The pressure decrease control valve increases an amount of pressurized oil flow from the wheel brake to the reservoir when wheel brake pressure decreases and decreases the amount of pressurized oil flow from the wheel brake when wheel brake pressure increases. The pressure increase and decrease control valves are formed integral.

A hydraulic pump assembly for use in combination with an accumulator comprises a pump housing provided with an inlet port for connection to a fluid reservoir and an outlet port for connection to the accumulator, a single cam shaft rotatably mounted within the housing to be driven by an electric motor, a first plunger pump assembly of large displacement capacity including a first plunger axially slidably disposed within the housing perpendicularly to the cam shaft to be reciprocated by engagement with the cam shaft, and a second plunger pump assembly of small displacement capacity including a second plunger axially slidably disposed within the housing perpendicularly to the cam shaft to be reciprocated by engagement with the cam shaft and opposed to the first plunger. An exhaust check valve of the first plunger pump assembly is interconnected to a suction check valve of the second plunger pump assembly.

Hydraulic pump assembly associated with accumulator

The present invention relates an antiskid apparatus for an automotive vehicle. The apparatus includes a cut-off valve which is connected between a master cylinder and a wheel cylinder and provides communication therebetween in response to wheel cylinder pressure and cuts off pressurized hydraulic fluid from the master cylinder when an antiskid operation is performed by the control system. A solenoid valve is positioned in a conduit which connects the wheel cylinder to the cut-off valve. The solenoid valve is also connected to a discharge side of a pump which circulates pressurized oil. When the solenoid is in a normal position, the wheel cylinder is connected to the cut-off valve in the discharge side of the pump. When changed over from the normal position, the solenoid valve disconnects the wheel cylinder from the cut-off valve and the discharge side of the pump and connects the wheel cylinder to a reservoir connected to an intake side of the pump.

An anti-skid apparatus for installation in a vehicle braking system between a master cylinder and a wheel brake cylinder. The anti-skid apparatus includes a hydraulic power pressure source connected to a fluid reservoir of the master cylinder to produce a hydraulic power pressure higher than a braking pressure applied to the wheel brake cylinder from the master cylinder, a regulator valve connected to the pressure source to control the power pressure in dependence upon a hydraulic pressure created in the master cylinder in braking operation, a first switchover valve disposed within a braking circuit connecting the master cylinder to the wheel brake cylinder and being arranged to be intermittently activated when a road wheel tends to be locked, the first switchover valve being connected to the reservoir to connect the wheel brake cylinder to the reservoir in its activated condition, a second switchover valve disposed within the braking circuit between the master cylinder and the first switchover valve and being arranged to be activated when the road wheel tends to be locked, a second switchover valve being connected to the regulator valve to interrupt the flow of pressurized fluid from the master cylinder and permit the flow of pressurized fluid from the regulator valve to the wheel brake cylinder through the first switchover valve.

Anti-skid apparatus for automotive vehicle

A piston for acting on both a master cylinder and a fluid pressure booster is slidably disposed in a housing and defines a pressure buildup chamber communicating with a wheel brake actuating cylinder on one end and a power chamber on an opposite end. The cylinder has a plurality of axial slots defined in an outer peripheral surface thereof and communicating with inlet, supply, and outlet ports, there being seals disposed in the axial slots.

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Chiryu, Japan

Hiromu Kuromitsu