Abstract: The present invention is directed to a braking stroke simulator for use in a brake system, which comprises a simulator piston moved in response to operation of a manually operated braking member, and an elastic element for providing a stroke to the simulator piston in response to braking operation force applied to the manually operated braking member, wherein restoring amount of the elastic element is restricted to set an initial load to be applied thereto. The elastic element includes a first elastic member made of rubber, and a second elastic member made of a helical spring, which is disposed in series with the first elastic member. The initial load applied to the first elastic member and the initial load applied to the second elastic member are set to be substantially equal to each other.

Abstract: A hydraulic brake device includes a hydraulic pressure supply passage for reducing the output hydraulic pressure by a first proportional solenoid valve and supplying it to a hydraulic passage leading from a pressure adjusting valve to the wheel cylinders, a second proportional solenoid valve disposed between the hydraulic pressure supply passage and the pressure adjusting valve for reducing the hydraulic pressure supplied from the hydraulic pressure supply passage, and a check valve parallel to the second proportional solenoid valve. Hydraulic pressure control during automatic brake control is carried out by the first and second proportional solenoid valves.

Abstract: The present invention is directed to a master cylinder having a braking stroke simulator, wherein a master piston is slidably accommodated in a housing having an atmospheric pressure chamber and a master pressure chamber, and a simulator piston is slidably accommodated in the housing to define a simulator chamber. An elastic member is provided for applying a stroke of the simulator piston in response to braking operation force applied to a manually operated braking member. Thus, the braking stroke simulator transmits the braking operation force to the master piston through the simulator piston and elastic member. A cut-off seal member is disposed in the housing for supporting the master piston, and placed to be applied with the pressure in the master pressure chamber in front of it and applied with the atmospheric pressure behind it. And, a passage is formed in the master piston to communicate the simulator chamber with the atmospheric pressure chamber when the master piston is placed in its initial position.

Abstract: The present invention is directed to a hydraulic brake apparatus provided with a pressure source for generating hydraulic pressure, a pressure regulator valve for regulating the hydraulic pressure generated by the pressure source in response to an input state, a master cylinder having a master piston for defining a pressure chamber for receiving therein the hydraulic pressure fed from the pressure regulator valve, and a master chamber for discharging hydraulic braking pressure. The hydraulic braking pressure discharged from the master chamber is set to be lower than the hydraulic pressure in the pressure chamber, to produce a pressure difference increased in response to advance of the master piston. A wheel brake cylinder is operatively mounted on each wheel of the vehicle for applying braking force to each wheel. A pressure control valve is disposed between the master chamber and the wheel brake cylinder to control the hydraulic braking pressure in the wheel brake cylinder.

Abstract: In a hydraulic brake device for a vehicle in which the output hydraulic pressure of a hydraulic pressure source is adjusted to a value corresponding to the brake operating amount with a pressure adjusting valve and the master cylinder is actuated under the adjusted hydraulic pressure, bottoming may occur in which the master piston makes a full stroke while the braking force is still low due to a vapor lock phenomenon. In the hydraulic brake device of this invention, the hydraulic pressure generated in a hydraulic pressure source is adjusted to a value corresponding to the brake operating amount with a pressure adjusting valve and introduced into a pressure chamber to actuate the master piston of the master cylinder.

Abstract: In a vehicle hydraulic brake device, the hydraulic pressure supplied from a hydraulic pressure source is adjusted to a value proportional to the brake operating amount by a pressure adjusting valve, and a master cylinder is actuated under the output hydraulic pressure of the pressure adjusting valve introduced into a pressure chamber to produce braking force. The output hydraulic pressure of the pressure adjusting valve and that of the master cylinder are detected with a pressure sensor and a master cylinder pressure sensor and compared with a bottoming detector.

Abstract: A master cylinder includes a cylinder housing having a cylinder bore, a seal cup disposed inside the cylinder bore, and a piston slidably disposed in the cylinder bore in sliding contact with the seal cup and defining a pressure chamber in cooperation with the housing and the seal cup. The piston includes a connecting passage which fluidly connects the pressure chamber with an atmospheric pressure chamber when the piston is in a retracted position. The seal cup cuts off fluid communication between the pressure chamber and the atmospheric pressure chamber through the connecting passage when the piston moves in its axial direction by a prescribed distance from its retracted position. The connecting passage is a stepped hole having a first end portion with a small diameter which communicates with the pressure chamber and a second end portion with a large diameter which opens onto an outer peripheral surface of the piston.

Abstract: The present invention is directed to a hydraulic brake apparatus provided with a pressure source for generating hydraulic pressure, a pressure regulating valve for regulating the hydraulic pressure generated by the pressure source in response to an input state, a master cylinder having a master piston for defining a pressure chamber for receiving therein the hydraulic pressure fed from the pressure regulating valve, and a master chamber for discharging hydraulic braking pressure. And, a pressure supply device is provided for supplying the hydraulic pressure from the pressure chamber into a hydraulic pressure circuit including the master cylinder and the wheel brake cylinder, when the hydraulic braking pressure discharged from the master cylinder is equal to or greater than a first predetermined pressure, and/or when the hydraulic pressure in the pressure chamber is equal to or greater than a second predetermined pressure.

Abstract: The present invention is directed to a hydraulic brake apparatus provided with a pressure source for generating hydraulic pressure, a hydraulic pressure boosting device having a pressure regulating valve for regulating the hydraulic pressure generated by the pressure source in response to braking operation by a vehicle driver, a master cylinder for advancing a master piston by the hydraulic pressure discharged from the hydraulic pressure boosting device, and a wheel brake cylinder operatively mounted on each wheel of the vehicle.

Abstract: An improved brake hydraulic pressure generating device is provided in which the hydraulic pressure supplied from a hydraulic pressure source is adjusted to a value corresponding to the brake operating force by means of a pressure adjusting valve which is activated according to displacement of an input piston or a simulator piston, and while the device is normal, a master cylinder is activated by the output hydraulic pressure. If the hydraulic pressure source or a hydraulic line connecting thereto fails, a sufficient braking force is ensured with a short stroke. There are provided a shutoff valve which shuts off communication between the simulator chamber and the atmospheric reservoir when the stroke of the input piston has exceeded a predetermined value, and a check valve which permits the flow of fluid from the atmospheric reservoir to the simulator chamber. This suppresses an unavailable stroke of the simulator piston without impairing the return of the simulator piston.

Abstract: The present invention is directed to a hydraulic brake apparatus provided with a pressure generator for generating hydraulic pressure in response to operation of a manually operated braking member, and a pressure regulating device disposed between the pressure generator and a wheel brake cylinder, and connected with a reservoir, so as to regulate the hydraulic pressure fed into the wheel brake cylinder to provide a desired pressure less than the hydraulic pressure generated by the pressure generator.

Abstract: A hydraulic brake device for applying a braking force to a wheel of a vehicle which can detect an air-containing in a hydraulic circuit. The hydraulic brake device includes a hydraulic pressure generating device for generating and outputting a hydraulic pressure in accordance with a brake operational amount, a wheel cylinder operated by the hydraulic pressure directly or indirectly supplied from the hydraulic pressure generating device for applying a braking force to a vehicle wheel, a brake operational amount detection device for detecting the brake operational amount, a pressure sensor for detecting an output hydraulic pressure outputted from the hydraulic pressure generating device, and a controller for detecting an air-containing in a hydraulic circuit by a response time relating to a rise of the output hydraulic pressure detected by the pressure sensor relative to a start of a rise of the brake operation amount detected by the brake operational amount detection device.

Abstract: In a vehicle hydraulic brake system of a type adapted to release brake fluid discharged from the wheel cylinders into a reservoir for a master cylinder during pressure reduction phase of antilock brake control or vehicle stability control, the volume of the pressure chamber of the master cylinder can decrease until it becomes impossible to further increase pressure as a result of repeated pressure increase and reduction. An inexpensive solution to this problem is provided. The solution includes means for estimating the amount of pressure increase and/or pressure reduction of the wheel cylinders, and solenoid valves provided in a line connecting a pressure source with the master cylinder pressure chamber and adapted to be opened for a calculated time period.

Abstract: A vehicle hydraulic brake apparatus includes a hydraulic pressure generator which generates a power pressure irrespective of operation of a brake pedal and a regulation valve which regulates the power pressure to a predetermined pressure corresponding to an operation force of the brake pedal and outputs it to an output chamber. A master cylinder generates a master cylinder pressure in a master cylinder chamber by forward movement of the master cylinder piston and a wheel brake cylinder is operated by the master cylinder pressure to apply braking force to a vehicle wheel. An auxiliary piston is located backward the master cylinder piston to define an auxiliary pressure chamber between the master cylinder piston and the auxiliary piston and to move the master cylinder piston forward by an auxiliary pressure in the auxiliary pressure chamber. A pressure modulating device decreases the predetermined pressure outputted from the output chamber to supply the auxiliary pressure to the auxiliary pressure chamber.

Abstract: A brake control device for a vehicle includes a master cylinder, a wheel cylinder, a brake pedal behavior simulator, a normally-open type electromagnetic valve, a normally-closed type electromagnetic valve, and a brake pressure control device. The brake pressure control device includes a pump, a reservoir, and two electromagnetic valves to increase and decrease wheel cylinder hydraulic pressure. When the brake pressure control device is normally operated, a hydraulic pressure in the wheel cylinder is controlled by the brake pressure control device. On the other hand, when the brake pressure control device malfunctions or is abnormally operating, the wheel cylinder hydraulic pressure is controlled by hydraulic pressure generated from the master cylinder. At least the normally-closed type electromagnetic valve is opened when the brake pedal is in the non-operational state.

Abstract: An improved brake hydraulic pressure generating device is provided in which the hydraulic pressure supplied from a hydraulic pressure source is adjusted to a value corresponding to the brake operating force by means of a pressure adjusting valve which is activated according to displacement of an input piston or a simulator piston, and while the device is normal, a master cylinder is activated by the output hydraulic pressure. If the hydraulic pressure source or a hydraulic line connecting thereto fails, a sufficient braking force is ensured with a short stroke. There are provided a shutoff valve which shuts off communication between the simulator chamber and the atmospheric reservoir when the stroke of the input piston has exceeded a predetermined value, and a check valve which permits the flow of fluid from the atmospheric reservoir to the simulator chamber. This suppresses an unavailable stroke of the simulator piston without impairing the return of the simulator piston.

Abstract: A brake stroke simulator includes a first movable member freely slidably disposed in a housing and defining a hydraulic pressure chamber at one end of the first movable member that is adapted to be supplied with hydraulic pressure corresponding to braking operation of a brake pedal, and a second movable member disposed at the other end of the first movable member in the housing movable integrally with the first movable member. A first spring biases the first movable member and a second spring biases the second movable member. A shock absorbing elastic member is compressed by the sliding movement of the first movable member against the biasing force of the first spring and is compressed by the sliding movement of the second movable member against the biasing force of the second piston.

Abstract: In a brake hydraulic pressure generating device in which the brake operating force is applied to a pressure adjusting valve through a stroke simulator and the hydraulic pressure supplied from the hydraulic pressure source is adjusted to a value corresponding to the brake operating force, during return of the brakes, the return stroke before the brake hydraulic pressure begins to drop is large, so that the brake feeling is bad. This invention proposes a solution to this problem. Hysteresis is imparted to the stroke simulator so that the output hydraulic pressure of the pressure adjusting valve for the stroke of the simulator piston stroke during increase of the brake operating force will be higher than that during reduction of the brake operating force by setting the sliding resistance of the simulator piston greater than that of the input piston.

Abstract: An improved hydraulic brake system for a vehicle is proposed which includes a hydraulic pressure supply unit for supplying hydraulic pressure from a pressure adjusting valve or an hydraulic pressure source to a pressure chamber of a master cylinder. In this type of brake system, when the hydraulic pressure supply unit is activated, the master piston of the master cylinder could retract to its original position, thus bringing the master pressure chamber into communication with the atmospheric reservoir. If this happens, the master cylinder pressure output will be lost completely. An inexpensive solution to this problem is proposed. A piston retraction restricting member is provided in a pressure chamber for applying pressure to the master piston.

Abstract: In a vehicle hydraulic brake system of a type adapted to release brake fluid discharged from the wheel cylinders into a reservoir for a master cylinder during pressure reduction phase of antilock brake control or vehicle stability control, the volume of the pressure chamber of the master cylinder can decrease until it becomes impossible to further increase pressure as a result of repeated pressure increase and reduction. An inexpensive solution to this problem is provided. The solution includes means for estimating the amount of pressure increase and/or pressure reduction of the wheel cylinders, and solenoid valves provided in a line connecting a pressure source with the master cylinder pressure chamber and adapted to be opened for a calculated time period.