Abstract: A brake system 1 of the present invention comprises a brake operating means 2 such as a brake pedal for carrying braking operation, a fluid variable stroke means 3 which variably controls the stroke of the brake operating means 2 by using fluid, and a braking force output means 4 which is actuated by the operation of the brake operating means 2 to produce braking forces. By manipulating the brake operating means 2, the braking force output means 4 performs the braking operation. The traveling rang of the brake operating means 2 i.e. the stroke can be changed variously by the fluid variable stroke means 3 using fluid. Since the stroke of the brake pedal can be changed as mentioned above, a proper pedal stroke can be obtained.

Abstract: In a vehicle brake apparatus for executing ABS control to prevent a wheel from locking in such a manner that braking force is controlled so as to keep a slip ratio of a wheel at a target slip ratio so that an excessive drop of a wheel speed from a vehicle body speed is adjusted, an output current for driving a braking actuator is set to a current on which oscillating waves are superimposed during ABS control so that the wheel speed changes to show oscillating waves. Even if the wheel speed once drops to an extent that the slip ratio exceeds the target slip ratio, further decrease of the wheel speed is restricted and the wheel speed turns to an increase soon and this cycle is repeated. Accordingly, there occurs no excessive drop of the wheel speed due to the response delay so that sufficient braking force is generated.

Abstract: A hydraulic-pressure counter-force mechanism 37 which produces a counter force when a brake booster is operated is made up of an input-side member 38 slidable disposed within a valve body 3, a second constant-pressure chamber 39 formed on the rear side of the input-side member and into which a pressure is introduced from a constant pressure chamber A, and a second constant-pressure chamber 39 formed on the front side of the input-side member and into which a pressure is introduced from a variable pressure chamber B. The counter force from the hydraulic-pressure counter-force mechanism 37 is reduced by an orifice passage 43 as counter-force reducing means in rapid operation for brake.

Abstract: In a disk brake, a first surface of a wedge member is in line contact via a first roller bearing with a surface of the piston and a second surface of the wedge member is also in line contact via a second roller bearing with a surface of the guide member. Each of the first surface of the wedge member and the surface of the piston is perpendicular to a piston axis and each of the second surface of the wedge member and the surface of the guide member is inclined by a given angle to the piston axis. When a drive unit moves the wedge member substantially perpendicularly to the piston axis, the piston moves axially and presses a frictional material against a disk. Since force transmitted from the wedge member to the piston acts parallel to the piston axis with a less moment in a direction of pressing the piston against a wall surface of the cylindrical bore so that the piston moves smoothly.

Abstract: In a vehicle brake apparatus for executing ABS control to prevent a wheel from locking in such a manner that braking force is controlled so as to keep a slip ratio of a wheel at a target slip ratio so that an excessive drop of a wheel speed from a vehicle body speed is adjusted, an output current for driving a braking actuator is set to a current on which oscillating waves are superimposed during ABS control so that the wheel speed changes to show oscillating waves. Even if the wheel speed once drops to an extent that the slip ratio exceeds the target slip ratio, further decrease of the wheel speed is restricted and the wheel speed turns to an increase soon and this cycle is repeated. Accordingly, there occurs no excessive drop of the wheel speed due to the response delay so that sufficient braking force is generated.

Abstract: When a passenger distinguishment system is produced, after a seat cover is attached to a seat cushion while applying a tension to the seat cover, a conditioning operation is performed to lessen an adverse effect of the tension with respect to sensitivities of plural sensor cells that are disposed between the sensor cushion and the seat cover. The conditioning operation can disperse the tension of the seat cover, so that the sensor cells can detect loads applied to the seat accurately.

Abstract: A method of calibrating sensitivities of a plurality of pressure sensing cells are disposed at a passenger seat to detect presence of a vehicle passenger.

Abstract: A hydraulic-pressure counter-force mechanism 37 which produces a counter force when a brake booster is operated is made up of an input-side member 38 slidable disposed within a valve body 3, a second constant-pressure chamber 39 formed on the rear side of the input-side member and into which a pressure is introduced from a constant pressure chamber A, and a second constant-pressure chamber 39 formed on the front side of the input-side member and into which a pressure is introduced from a variable pressure chamber B. The counter force from the hydraulic-pressure counter-force mechanism 37 is reduced by an orifice passage 43 as counter-force reducing means in rapid operation for brake.

Abstract: A counter-force mechanism (37), which produces a counter force when a brake booster is operated, is made up of an input-side member (38) slidably disposed within a valve body (3), a second constant-pressure chamber (39) formed on the rear side of the input-side member and into which a pressure is introduced from a constant pressure chamber (A), and a second constant-pressure chamber (39) formed on the front side of the input-side member and into which a pressure is introduced from a variable pressure chamber (B). The counter force from the counter-force mechanism (37) is reduced by an orifice passage (43) as a counter-force reducing means in rapid operation of the brake.

Abstract: A fluid pressure boosting device of the present invention performs jumping action at a higher servo ratio until fluid pressure in a power chamber (25) reaches a first predetermined value and a rear end (20e) of a reaction piston (20)comes in contact with a step of an input shaft (18). Since a switching valve is set in a first position I until the fluid pressure in the power chamber (25) reaches a second predetermined pressure, a reaction chamber (41) is connected to the reservoir (33) so as to be at atmospheric pressure. In this state, the normal brake control at a lower servo ratio is performed. As the fluid pressure in the power chamber (25) reaches a second predetermined value, the switching valve is set in a second position II by the fluid pressure so that the pressurized fluid in the power chamber is introduced into the reaction chamber (41). The fluid pressure in the reaction chamber 41 acts on the step between the reaction piston (20) and the input shaft (18) so that the servo ratio becomes higher.

Abstract: In a brake boosting system the present invention, as it is decided that brake assist is necessary, a pump 53 is driven, and a solenoid valve 72 is switched to its communication position, and a solenoid shut-off valve 75 is opened. Then, the pump 53 sucks brake fluid from a reservoir 9 through the solenoid valve 72 and sends out the brake fluid to the pressure intensifying chamber 21 through the solenoid shut-off valve 75. At this point, an output shaft 11 has already advanced and a radial hole 38 is positioned ahead of a seventh cup sealing member 31 so that the pressure intensifying chamber 21 and the reaction chamber 33 are shut off from the reservoir 9 so as to be in the sealed state. Therefore, pump discharge pressure is supplied to the pressure intensifying chamber 21 and the reaction chamber 33 so that the pressure in these chambers is intensified. Since the intensified pressure acts on the primary piston 12, the master cylinder pressure is intensified to a value greater than that of normal braking.

Abstract: A brake booster includes a solenoid disposed within a valve body. When the solenoid is energized under the inoperative condition of the brake booster, a piston associated with the solenoid is moved to its operative position to close a vacuum valve while opening an atmosphere valve. This allows the brake booster to be operated as an automatic brake without depressing a brake pedal. The brake booster also comprises output restriction means which may comprise a spring 55 shown in FIG. 1, for example, whereby as the output increases when the brake booster is operated as an automatic brake, the output restriction means operates to cease an increase in the output. With this arrangement, if the solenoid is energized inadvertently independently from the intent of a driver, the occurrence of a quick braking action is avoided, but a gentle braking action is assured, thus improving the safeguard.

Abstract: A tandem brake booster includes a solenoid within a valve body, and the solenoid may be energized to move a first tubular member disposed on the valve body rearward. When an input shaft is driven forward in the inoperative condition of the brake booster, a vacuum valve is closed while an atmosphere valve is opened in the similar manner as occurs in the prior art, thus actuating the tandem brake booster 1. When an input or the force of depression applied to a brake pedal rises to a given value X during the operative condition of the brake booster, the solenoid is energized, whereupon the first tubular member is moved rearward relative to the valve body, and the valve element is also moved rearward. This opens the atmosphere valve which has been closed during the servo balance condition, allowing a further introduction of the atmosphere into variable pressure chambers B, D, enabling a rise in the output even though the input remains unchanged.

Abstract: An anti-skid control system has a determining device which determines whether no pressure increasing output is scheduled to be generated for any of pressure increasing valves provided for plural wheels for at least a predetermined time period. When no pressure increasing output is scheduled to be generated for any of the pressure increasing valves for at least the predetermined time period, the pressure increasing valves are controlled so that a pressure increasing operation is carried out for at least one wheel cylinder to allow brake fluid to flow from a master cylinder to the wheel cylinder.

Abstract: A brake booster which permits an axial relative movement between a power piston and a valve body is disclosed. An arrangement is made which prevents a brake reaction from being transmitted to a brake pedal. As an alternative therefor, pseudo-reaction imparting means transmits a pseudo-reaction to a brake pedal. A rear end of the valve body is covered by a tubular cover and bellows connected thereto, and its internal space is maintained in communication with a constant pressure chamber. The bellows has an effective diameter which is chosen to be of an equal size to the diameters of a vacuum valve seat and an atmosphere valve seat. This allows a pseudo-reaction and a brake pedal stroke to be obtained which depend on the force with which a brake pedal is depressed if a negative pressure within the constant pressure chamber varies, thus imparting a better brake feeling to a driver.

Abstract: An automatic brake booster includes a solenoid which drives a plunger, forming part of a valve mechanism, forward to switch a flow path in the valve mechanism, separately from an input shaft. A piston is mounted on the plunger, and the atmospheric pressure is introduced into an atmospheric pressure chamber disposed forwardly of the piston while a pressure which prevails in constant pressure chambers A, C is introduced into a negative pressure chamber disposed rearwardly of the piston, thus urging the piston rearward. Preferably, the piston has a pressure responsive area which is substantially equal to the pressure responsive area of an atmosphere valve seat formed on a plunger. This arrangement allows a variation in the output from the brake booster to be minimized or reduced substantially to zero if there is a variation in the magnitude of a negative pressure which is introduced into the constant pressure chambers A, C.

Abstract: A brake system has wheel cylinders for producing a braking force in wheels using pressurized brake fluid transmitted through a main conduit from a master cylinder, a reservoir for storing brake fluid, a sideslip preventing device for when a sideslip state of the vehicle is detected supplying brake fluid to the wheel cylinder corresponding to a sideslip controlled wheel and producing a braking force in the sideslip controlled wheel, a first conduit used for supplying brake fluid from the reservoir to the wheel cylinders by the pump and a first valve for switching this first conduit between an open state and a closed state. The sideslip preventing device, when the sideslip state is detected during non-braking of the vehicle, makes the first valve open-state and thereby conducts supply of brake fluid through the first conduit from the reservoir to the wheel cylinder by a pump.

Abstract: Vibration observed in a tire wheel portion exhibits a resonant vibration phenomenon in which vibration fluctuates between a wheel and a surface of a tire. This phenomenon shows different characteristics depending upon how the surface of the tire is in contact with a road surface. Here, a detector derives a parameter corresponding to a gradient of a coefficient of friction based on these characteristics and detects a brake condition. Also, a controller executes ABS control based on such parameter.

Abstract: To provide optimal braking force control using braking operation data, an ECU in a brake force control system detects a braking operation according to fluctuation components of wheel rotation. That is, the ECU calculates the wheel acceleration and sets a reference load level for the braking operation according to a road surface coefficient of friction at the wheel tire. When the amplitude of the wheel acceleration increases and exceeds the reference load level, the braking load is determined to be heavy. If the braking load is heavy, the ECU decreases the brake oil pressure of the wheel being detected. In this way, the slip ratio can be controlled around a peak road surface coefficient of friction.

Abstract: When oil flows from within a seat valve along an oil path in a valve, structure is such that a negative pressure is generated to draw a ball in the direction of the seat valve. That is, the force in the direction of valve closure is actively utilized, the valve does not perform a full stroke in a certain differential pressure range, and increases in a pulsed manner in a minute-stroke state, i.e., in a state where the passage cross-sectional area of the valve is small. Therefore, effective control becomes possible without a large pressure increase.