Abstract: An apparatus for detecting a longitudinal force of a tire is provided with at least one mark (3) provided in on one circumferential line (j) in a tire (2), a first sensor (5) disposed in a vehicle body side (4) and capable of detecting a passage of the mark (3), a second sensor (7) capable of detecting a rotation angle (?) of an axle (6), and a computing device (8) for computing a longitudinal force (Fr) of the tire (2) on the basis of an information of the first and second sensors (5, 7). The computing device (8) sequentially stores a rotation angle (?r) of the axle (6) when the mark (3) passes through the first sensor (5).

Abstract: A brake torque control device obtains inertia torque Tine based upon an equation of motion (Tine=Tw?Ft·Rt) about the rotation of a tire based upon a wheel torque Tw according to a brake torque exerted on the tire, road friction force Ft and a radius Rt of the tire. When the inertia torque Tine exceeds a predetermined reference value, road friction force Ft at this time is set as estimated maximum road friction force Fmax. The instructed brake torque is calculated under the condition that the value that is obtained by adding the predetermined value corresponding to the inertia torque Tine to the torque Fmax·Rt based upon this estimated maximum road friction force Fmax is set as an upper limit value of the instructed brake torque. This allows to clearly set, as one value, the target value of the instructed brake torque upon an ABS control, thereby being capable of more accurately executing the pressure-increasing control and pressure-reducing control of the brake fluid pressure.

Abstract: A condition of hydraulic fluid conducted from an accumulator to an operation device via a pressure control unit, is evaluated by determining a pressure (Pa) of the fluid in a flow path interconnecting the accumulator and the control unit, and determining a stabilization time (T) when an absolute value of a pressure gradient per unit time of the pressure falls below a predetermined value. A pressure drop (?Pa) of the pressure is determined during a period between a time (T0) when the pressure begins to decrease, or at a time before the time (T0) and the stabilization time (T). The pressure drop is compared with a predetermined pressure drop that is obtainable under normal conditions. An increase in (?Pa) can signify the entry of air into the hydraulic fluid, or a leakage of the hydraulic fluid.

Abstract: An apparatus for detecting a longitudinal force of a tire is provided with at least one mark (3) provided in on one circumferential line (j) in a tire (2), a first sensor (5) disposed in a vehicle body side (4) and capable of detecting a passage of the mark (3), a second sensor (7) capable of detecting a rotation angle (?) of an axle (6), and a computing means (8) for computing a longitudinal force (Fr) of the tire (2) on the basis of an information of the first and second sensors (5, 7). The computing means (8) sequentially stores a rotation angle (?r) of the axle (6) when the mark (3) passes through the first sensor (5).

Abstract: A brake system and a brake device for use with automobiles is provided in which braking energy stored in an auxiliary pressure source can be effectively used for braking, even if an electrical system fails. The vehicle brake system includes a proportional pressure control valve for generating braking liquid pressure by adjusting the braking energy stored in the auxiliary pressure source. A passage transmits the liquid pressure generated by a brake pedal stroke, a switching valve opens the passage in the powered condition and closes the passage in the off-powered condition, and an auxiliary control portion activates the proportional pressure control valve. Even in the off-powered condition, the high pressure accumulated in the auxiliary pressure source can be used to adjust the required braking liquid pressure at the proportional pressure control valve.

Abstract: A method is provided for measuring a pressure of a hydraulic fluid that is supplied from a hydraulic fluid control device (1) to a operation device (6). The method includes measurement of a first pressure (Pm) and a second pressure (Pa). The first pressure is the pressure of the hydraulic fluid within a first flow path (P3 to P8) connecting a pressure control unit (3) and the operation device. The second pressure is the pressure of the hydraulic fluid within a second flow path (P11, P12) connecting an accumulator (22) and the pressure control unit. Then, a stabilization time (T) is determined. The stabilization time is the time when a pressure gradient per unit time of the second pressure become to be smaller than a predetermined value. Thereafter, a pressure (Pw) of the hydraulic fluid at the operation device is determined based on the first pressure that is measured at the stabilization time or at a time immediately after the stabilization time.

Abstract: A mixed air amount alarm device is provided which determines the amount of air present in a hydraulic circuit between a hydraulic pressure source and an instrument driven by hydraulic pressure, and produces an alarm if the air amount is excessive, a situation is prevented in which an alarm is produced or not produced according to change of the air amount (volume) resulting from temperature change, and it is possible to stop an alarm if potential danger disappears and a safe state is recovered due to spontaneous release of air out of the hydraulic circuit. If the air amount is determined excessive, this is stored in a nonvolatile memory, and even if air amount excessiveness determination is not made at the next activation of the hydraulic device, the content of the nonvolatile memory is checked and an alarm is produced if air amount excessiveness determination has not been made before.

Abstract: A method is provided for measuring a pressure of a hydraulic fluid that is supplied from a hydraulic fluid control device (1) to a operation device (6). The method includes measurement of a first pressure (Pm) and a second pressure (Pa). The first pressure is the pressure of the hydraulic fluid within a first flow path (P3 to P8) connecting a pressure control unit (3) and the operation device. The second pressure is the pressure of the hydraulic fluid within a second flow path (P11, P12) connecting an accumulator (22) and the pressure control unit. Then, a stabilization time (T) is determined. The stabilization time is the time when a pressure gradient per unit time of the second pressure become to be smaller than a predetermined value. Thereafter, a pressure (Pw) of the hydraulic fluid at the operation device is determined based on the first pressure that is measured at the stabilization time or at a time immediately after the stabilization time.

Abstract: A brake torque control device obtains inertia torque Tine based upon an equation of motion (Tine=Tw?Ft·Rt) about the rotation of a tire based upon a wheel torque Tw according to a brake torque exerted on the tire, road friction force Ft and a radius Rt of the tire. When the inertia torque Tine exceeds a predetermined reference value, road friction force Ft at this time is set as estimated maximum road friction force Fmax. The instructed brake torque is calculated under the condition that the value that is obtained by adding the predetermined value corresponding to the inertia torque Tine to the torque Fmax·Rt based upon this estimated maximum road friction force Fmax is set as an upper limit value of the instructed brake torque. This allows to clearly set, as one value, the target value of the instructed brake torque upon an ABS control, thereby being capable of more accurately executing the pressure-increasing control and pressure-reducing control of the brake fluid pressure.

Abstract: A piston-cylinder mechanism includes a cylinder (50) that defines a cylindrical bore (51). Two pistons (52, 53) are disposed within the cylindrical bore, so that a first pressure chamber (57), a second pressure chamber (58) and a third pressure chamber (59) are defined within the cylindrical bore. The first pressure chamber and one of the second and third pressure chambers individually receive a supply of a pressurized fluid. The pressurized fluid is delivered individually from the second pressure chamber and the third pressure chamber to respective external devices (16, 17). A valve (60; 160) is arranged between one of the second pressure chamber and the third pressure chamber and the corresponding external device. The valve is operable to open and close when the one of the second pressure chamber and the third pressure chamber is expanded and contracted, respectively, due to the movement of the pistons.

Abstract: A hydraulic pressure control device is provided which is capable of pressure reduction and pressure increase by electronic control without changing over hydraulic circuits, and which is reliable and simple in structure. A vehicle brake device using such a control device is also provided. A pressure chamber and an offset spring are provided in a hydraulic pressure control valve. A spool valve is moved to a position corresponding to brake operating force, thereby changing over connections between the output port and the discharge port and between the output port and the input port, and adjusting the degrees of opening of valve portions. In this manner, the hydraulic pressure at the output port to a value corresponding to the brake operating force is controlled.

Abstract: A mixed air amount alarm device is provided which determines the amount of air present in a hydraulic circuit between a hydraulic pressure source and an instrument driven by hydraulic pressure, and produces an alarm if the air amount is excessive, a situation is prevented in which an alarm is produced or not produced according to change of the air amount (volume) resulting from temperature change, and it is possible to stop an alarm if potential danger disappears and a safe state is recovered due to spontaneous release of air out of the hydraulic circuit. If the air amount is determined excessive, this is stored in a nonvolatile memory, and even if air amount excessiveness determination is not made at the next activation of the hydraulic device, the content of the nonvolatile memory is checked and an alarm is produced if air amount excessiveness determination has not been made before.

Abstract: A pressure-responsive type pressure holding valve is proposed which serves to hold the hydraulic pressure in a circuit connected to a spool valve. A piston valve biased by a spring is mounted in a housing formed with a valve chamber, a small-diameter bore and a large-diameter bore. The outer periphery of the small-diameter portion of the piston valve is sealed by a seal member. A first port opened and closed by a valve head at the tip of the piston valve is connected to a circuit that needs pressure holding, a second port to a circuit in which minute leak can occur, and a third port to a source of hydraulic pressure for opening the valve.

Abstract: A poppet type solenoid valve used in an electronically controllable vehicle hydraulic brake system is proposed which suppresses sound and vibration and simultaneously eliminates malfunction. For these effects, the following conditions have to be satisfied: FSP/(r2−B2)<67  (1) FSP·St2/(r2−B2)>29  (2) wherein FSP is the force of the spring, r is the tip diameter of the poppet, St is the stroke of the poppet, and B is the diameter of the area of the poppet where the valve-opening force by hydraulic pressure does not work on the poppet under the Bernoulli effect.

Abstract: A brake system and a brake device for use with automobiles is provided in which braking energy stored in an auxiliary pressure source can be effectively used for braking, even if an electrical system fails. The vehicle brake system includes a proportional pressure control valve for generating braking liquid pressure by adjusting the braking energy stored in the auxiliary pressure source. A passage transmits the liquid pressure generated by a brake pedal stroke, a switching valve opens the passage in the powered condition and closes the passage in the off-powered condition, and an auxiliary control portion activates the proportional pressure control valve. Even in the off-powered condition, the high pressure accumulated in the auxiliary pressure source can be used to adjust the required braking liquid pressure at the proportional pressure control valve.

Abstract: A brake system and a brake device for use with automobiles is provided in which braking energy stored in an auxiliary pressure source can be effectively used for braking, even if an electrical system fails. The vehicle brake system includes a proportional pressure control valve for generating braking liquid pressure by adjusting the braking energy stored in the auxiliary pressure source. A passage transmits the liquid pressure generated by a brake pedal stroke, a switching valve opens the passage in the powered condition and closes the passage in the off-powered condition, and an auxiliary control portion activates the proportional pressure control valve. Even in the off-powered condition, the high pressure accumulated in the auxiliary pressure source can be used to adjust the required braking liquid pressure at the proportional pressure control valve.

Abstract: This invention is to provide a brake system and a brake device for use of automobiles, in which a braking energy stored in an auxiliary pressure source can be exploited effectively for a braking purpose, even if an electrical system fails. In particular, the vehicle brake system includes a proportional pressure control valve 80 for generating braking liquid pressure by adjusting the braking energy stored in the auxiliary pressure source 30. Also the vehicle brake system comprises a passage 75 transmitting the liquid pressure generated by a stroke of a brake pedal 1, a switching valve 76 opening the passage in the powered condition and closing the same in the off-powered condition, and an auxiliary control portion 81 activating the proportional pressure control valve 80. Even in the off-powered condition, the high pressure accumulated in the auxiliary pressure source 30 can be used to adjust the required braking liquid pressure at the proportional pressure control valve 80.

Abstract: A control method of a hydraulic pressure source-driven type vehicle hydraulic pressure brake system in which no irritating noises or vibrations are produced during stoppage of the vehicle and which does not consume electric power in waste. When the vehicle stops and the surroundings become quiet, by detecting stoppage of the vehicle by a sensor for detecting the rotation of a wheel, stopping a motor for a pump for producing brake hydraulic pressure, and opening a solenoid valve in a master cylinder passage bringing the master cylinder and the wheel cylinder into communication with each other, it is possible to prevent noises or vibrations from the motor and wasteful consumption of electric power.

Abstract: A hydraulic pressure control device is proposed in which using a proportional pressure control valve having a built-in spool valve, the hydraulic pressure for wheel brakes is adjusted to a value corresponding to the magnitude of an external force applied to the spool valve, non-electrical pressure adjustment can be done both in a normal state and in an emergency, and the structure is simplified. The brake pedal is coupled through a spring to the spool valve of the proportional pressure control valve having a solenoid for generating a spool-driving force, and the brake pedal force is applied to the spool valve as an external force so that not only in an emergency but in a normal state, pressure is adjusted by the brake pedal force.

Abstract: A hydraulic pressure control device is provided in which a proportional pressure control valve is actuated by operating the brake pedal to adjust the hydraulic pressure supplied from a pressure source to the wheel brakes to a value corresponding to the pedal operating amount. Also, a brake device for a vehicle using it is provided. The proportional pressure control valve is integrated with a hydraulic pressure generator to transmit the input from the brake pedal to a spool valve in the control valve through a first piston, first spring, second piston and second spring of the hydraulic pressure generator. If the pressure source or the wheel brakes in a first line fail, after the second piston has made a full stroke, brake fluid in a fluid chamber is pressurized, so that the hydraulic pressure generated is supplied to wheel brakes in a second line through a copy valve which is open.