Abstract: An object of this invention is to smoothen the operation and stabilize the output of a negative pressure type booster device for a hydraulic brake device of the stroke-independent type, in which the brake operating force is amplified using negative pressure of an engine and the master cylinder is actuated using the amplified force. Airtight sealing between a power piston and a valve piston which is axially movable relative to the power piston, and between a plunger coupled to an input shaft and the valve piston are carried out by rolling seals to prevent inaccurate movement of the valve piston, which tends to occur when such airtight sealing is carried out using slide seals.

Abstract: A negative pressure type brake hydraulic pressure generating device is proposed in which the stroke on the operating side can be set independently of the stroke on the output side. A slide resistance imparting means is provided between the fixed shell and a piston having a built-in control valve introducing atmospheric air to cancel the slide resistance which is the cause of increased stroke hysteresis of the piston, i.e. the slide resistance applied to the piston at airtight seal portions between the power plate and the piston.

Abstract: It is aimed to improve brake feeling of a negative pressure type brake hydraulic pressure generating device in which the stroke on the operating side can be set independently of the stroke on the output side. A spring for setting the stroke on the operating side is formed of coil springs arranged in series to impart the spring nonlinear characteristics, thereby biasing a piston, which can be moved axially relative to a power plate and includes a control valve for introducing atmospheric air, in the return direction.

Abstract: A brake hydraulic pressure generator is proposed in which the brake stroke fluctuate less when the amount of brake fluid consumed in the wheel brakes fluctuates. Even when the brake pedal force is increased after the brake assisting force has reached its maximum, the reaction force to the pedal force as well as the master cylinder pressure increases corresponding to the increased pedal force. The brake hydraulic pressure generator has a control valve including a spool and a cylinder and adapted to control the hydraulic pressure in a dynamic pressure chamber to a value corresponding to the stroke of an input shaft. It further includes a pressure sensor, a solenoid valve and a fluid chamber.

Abstract: A piston assembly is provided which prevents and detects binding of a piston which is always fixed in a normal state and required to move only in case of a failure of a hydraulic or pneumatic system. One end of a second piston has a tubular extension. A first piston is inserted in the tubular extension. The first piston is acted by the hydraulic pressure introduced from a controlled pressure generating unit into a first fluid chamber and is kept in its initial position against a brake operating force transmitted from a brake pedal through a first spring. On the other hand, the second piston moves until the hydraulic pressure in the second fluid chamber becomes substantially equal to the hydraulic pressure in the first fluid chamber. By the movement of the second piston, the sliding portions between the first and second pistons are frequently slid. This makes it possible to prevent and detect binding by comparing the hydraulic pressures in the first and second fluid chambers.

Abstract: Improving operating feelings and energy saving are aimed for a brake system of the type in which a predetermined differential pressure is produced between a master cylinder and wheel cylinders by a hydraulic pressure limit/changeover device during regenerative braking, and at the end of regenerative braking, the differential pressure is cancelled by increasing the pressure in the wheel cylinders with fluid sucked up from a reservoir for pressure increase by an electric pump. A reservoir for pressure increase, which is also used as a stroke simulator, is provided on the master cylinder side of the hydraulic pressure limit/changeover device, an on-off valve and a check valve are provided parallel to each other on the inlet side of the reservoir for pressure increase.

Abstract: Improving operating feelings and energy saving are aimed for a brake system of the type in which a predetermined differential pressure is produced between a master cylinder and wheel cylinders by a hydraulic pressure limit/changeover means during regenerative braking, and at the end of regenerative braking, the differential pressure is cancelled by increasing the pressure in the wheel cylinders with fluid sucked up from a reservoir for pressure increase by an electric pump. A reservoir for pressure increase, which is also used as a stroke simulator, is provided on the master cylinder side of the hydraulic pressure limit/changeover means, an on-off valve and a check valve are provided parallel to each other on the inlet side of the reservoir for pressure increase, so that the split point hydraulic pressure and the pressure-reducing ratio of a proportional pressure-reducing valve for supplying brake fluid toward the wheel cylinders during the initial period of braking can be brought unlimitedly close to zero.

Abstract: A brake fluid pressure control device including a power pump provided in a fluid supply line for discharging fluid into the main fluid line. An on-off valve is provided in the main fluid line upstream of the point at which the outlet circuit of the pump merges with the main fluid line. A fluid reservoir is provided in the fluid supply line upstream of the pump. For automatic braking, a changeover valve is changed over to supply fluid in the first chamber into the inlet port of the pump. When the automatic braking is off, the inlet and outlet ports of the pump are connected to the second and first chambers of the reservoir, respectively, to supply fluid into the first chamber.

Abstract: A proportional pressure control valve of the type in which a spool is driven by an electromagnet to control the load pressure to a value corresponding to the electromagnet energizing current is provided to simplify and reduce the cost of such valve. The number of springs has been reduced to one by biasing the spool with a spring through an actuating element of the electromagnet. Also, by providing a reaction force piston near a low-pressure pressure chamber, the need to form a hole in the actuator at a functionally important portion has been eliminated. Furthermore, arrangement is such that the load pressure acts on the spool in the same direction with the force of the electromagnet to supplement it. Further, the actuating element is formed integrally with the spool to eliminate any sliding portions from the actuating element, and a gap is formed between the actuation element and the member surrounding the actuating element to reduce the sliding resistance thereof.

Abstract: A solenoid controlled valve comprises a spool. One end side of the spool is slidably inserted into a first fluid chamber of a sleeve in a fluid tight condition. The other end of the spool is loosely inserted into a second fluid chamber. The spool with a stationary orifice is provided in an inlet path extending in axial direction. A spring for urging the spool and a movable core fixed to the spool, and a coil are provided. When electric current is supplied to the coil, the movable core is attracted against the spring force and the spool moves opposite to the urging direction of the spring, so that the external peripheral face of the spool closes the first port and the second port.

Abstract: In a solenoid valve, a coil is disposed on the electronic control side, and is resin injection molded integrally with a resin case housing a circuit board on which electronic components are mounted. Before a hydraulic control unit and electronic control unit are connected, an end of a connecting pin of the coil is electrically connected to wiring of the circuit board. A cover 20 of similar material is pressed and welded onto the resin case to assure a waterproof structure around the circuit board. Finally, a magnetic member or magnetic plate, constituting part of a magnetic circuit provided separately from or integrally molded with the resin case is fastened by a bolt to unitarily connect both units.

Abstract: A brake fluid pressure control device which is simple in structure and inexpensive, which has the functions as both an antilock controller and a traction controller, and which is capable of automatically increasing braking pressure with pumps while the driver is treading the brake pedal. Shutoff valves serving as fluid sources for pumps are provided in a fluid circulation type antilock control device. When the brake pedal is treaden, the shutoff valves close under the master cylinder pressure. While the shutoff valves are closed, no fluid can be supplied to the pump. But in this state, changeover valves open, so that fluid can be supplied from the master cylinder to the pumps through the changeover valves. Check valves are further provided to prevent the fluid supplied to the pumps from flowing into dumped fluid reservoirs.

Abstract: If the pump for antilock fluid pressure control is used as a fluid pressure source for automatic brake control, the pressure rising speed will drop, deteriorating the responsiveness of the device, or otherwise an extremely large pump-driving motor has to be used. To solve this problem, a fluid supply amplifier and a pressure-responsive valve are provided parallel to each other between a pump and a wheel brake fluid pressure control valve. A solenoid valve is closed until the output fluid pressure rises to a predetermined value to amplify the amount of fluid discharged from the pump with the fluid supply amplifier. It is thus possible to increase pressure sufficiently quickly. At the same time, it is possible to increase the output of the pump-driving motor. When the output fluid pressure exceeds the predetermined value, the pressure-responsive valve opens, so that brake fluid is now supplied directly from the pump into the wheel brake. The brake pressure can thus be increased to a high level.

Abstract: A flow control valve assembly has a high degree of liquid-tightness and good flow controllability, even if a high-pressure, low-viscosity fluid is used. A housing of the valve assembly is formed with an inlet port and an outlet port, and a spool inserted in the housing. First and second fluid chambers for applying fluid pressures on both ends of the spool communicate with each other through a fluid passage having an orifice. The opening of the valve portion is adjusted by the movement of the spool so that the spool driving force produced by the difference in the pressures applied to both ends of the spool balances with a biasing force, whereby a fluid flows through the orifice at a controlled rate. This control valve assembly has an elastic annular seal. When the spool moves toward the annular seal, the land portion on the spool outer periphery is adapted to butt the seal, thereby closing the fluid passage. In this closed state, fluid leakage is reduced substantially to zero.

Abstract: A three position solenoid controlled valve comprising: a housing having first, second and third ports; first and second valve bodies for bringing the first and second ports into and out of communication with each other and the second and third ports into and out of communication with each other, respectively; first and second urging members for urging the first and second valve bodies in a valve opening direction and a valve closing direction, respectively; an electromagnetic urging device and a movable member which is displaced by the electromagnetic urging device so as to close and open the first and second valve bodies against urging forces of the first and second urging members, respectively such that the first valve body brings the first and second ports out of communication with each other through relative displacement between the housing and the first valve body.

Abstract: A compact, cost-effective, high-performance, highly reliable brake fluid controller functioning both as a antilock controller and a traction controller. This controller is basically a fluid-return type antilock brake controller with a relief valve and a shutoff valve further added thereto. The shutoff valve has a fluid chamber and an atmospheric-pressure chamber that are defined by a piston. A valve body movable together with the piston closes and opens fluid communication between a discharged fluid reservoir and a fluid supply line. During traction control mode, fluid is supplied to the pump from the fluid chamber. With this arrangement, it is possible to omit an intermediate reservoir which was necessary in a conventional controller of this type. It is also possible to reduce the resistance to the suction force of the pump to a minimum.

Abstract: A three position solenoid controlled valve comprising: a housing having first, second and third ports; first and second valve bodies for bringing the first and second ports into and out of communication with each other and the second and third pores into and out of communication with each other, respectively; first and second urging members for urging the first and second valve bodies in a valve opening direction and a valve closing direction, respectively; an electromagnetic urging device and a movable member which is displaced by the electromagnetic urging device so as to close and open the first and second valve bodies against urging forces of the first and second urging members, respectively such that the first valve body brings the first and second ports out of communication with each other through relative displacement between the housing and the first valve body.

Abstract: The valve portion of pressure control valve tends to be unstable because when the valve is opened, the valve opening pressure intensifies. To prevent this, the valve portion of the pressure control valve is in the form of a puppet valve so that the valve body of the valve portion receives the pressure of a dynamic pressure source in the valve-opening direction and receives the pressure of an fluid pressure introducing chamber in the valve-closing direction. With this arrangement, when the valve opens and the dynamic pressure source pressure drops, the valve-closing force increases, so that the pressure control valve shows a stronger tendency to close. This prevents the freefall of the pressure source pressure, so that the behavior of the valve portion stabilizes. Thus, it is possible to prevent vibrations and abnormal noise.

Abstract: The present invention provides a flow control valve which makes it possible to prevent the leakage of hydraulic fluid when the valve is closed while continuously controlling the flow rate. An axially slidable piston (12) housed in a housing (11) provided with a first port (13) and second port (16) is urged by an electromagnet (20). A first closing valve (14) for connecting and isolating the first port (13) and first fluid chamber (A), with a valve seat portion (14C) opened opposite one end portion of the piston (12) in the first fluid chamber (A) and a valve body (14B) which is seated in and separated from the valve seat portion in accordance with the axial displacement of the piston (12), is provided between the first port (13) and the first fluid chamber (A). An orifice (15) is provided in the conduit connecting the first fluid chamber (A) and the second fluid chamber (B).

Abstract: A flow control valve assembly has a high degree of liquid-tightness and good flow controllability, even if a high-pressure, low-viscosity fluid is used. A housing of the valve assembly is formed with an inlet port and an outlet port, and a spool inserted in the housing. First and second fluid chambers for applying fluid pressures on both ends of the spool communicate with each other through a fluid passage having an orifice. The opening of the valve portion is adjusted by the movement of the spool so that the spool driving force produced by the difference in the pressures applied to both ends of the spool balances with a biasing force, whereby a fluid flows through the orifice at a controlled rate. This control valve assembly has an elastic annular seal. When the spool moves toward the annular seal, the land portion on the spool outer periphery is adapted to butt the seal, thereby closing the fluid passage. In this closed state, fluid leakage is reduced substantially to zero.