Toyota Jidosha Kabushiki Kaisha

Other

Fumiaki Kawahata

Kiyoharu Nakamura

Akira Sakai

Masayasu Ohkubo

Akihiro Otomo

Hirohiko Morikawa

Akihiro Ohtomo

Tetsuya Miyazaki

Masashi Ito

Eiji Nakamura

Amane Shimura

Hiroaki Yoshida

Shinichi Soejima

Kazunori Kagawa

Kenji Shirai

Hiroshi Toda

Yutaka Ohnuma

Hitoshi Matsui

Mark Evans

Kimihiro Matsuki

A braking pressure control apparatus including a first pressure source including a power-operated pressurizing device, a second pressure source operable by a manually operable brake operating member to pressurize a fluid to a pressure higher than a level corresponding to the operating force of the brake operating member, a switching device for selectively placing the braking system in a first state in which a brake cylinder is operated with the fluid pressurized by the first pressure source and a second state in which the brake cylinder is operated with the fluid pressurized by the second pressure source, and a change restricting device operable upon a switching between the first and second states, to restrict a change of the operating state of the brake operating member and a change of the brake cylinder pressure, which change take place due to the switching, or a switching control device for controlling the switching device on the basis of the running condition of a vehicle whose wheel is braked by the braking pressure.

Braking pressure control apparatus capable of switching between two brake operating states using power-operated and manually operated pressure sources, respectively

In a hydraulic brake pressure control system, a master cylinder generates a brake fluid pressure proportional to a brake pedal pressure and a high-pressure supply device generates an increased brake fluid pressure. A hydraulic circuit having a wheel cylinder device is capable of performing a master cylinder control to control a wheel cylinder pressure by using the pressure generated by the master cylinder, and capable of performing a brake-by-wire control to control the wheel cylinder pressure by using the pressure generated by the high-pressure supply device. The hydraulic brake pressure control system includes a master cut valve device which controls a flow of brake fluid from the master cylinder into the wheel cylinder device. A wheel cylinder sensor device outputs a signal indicative of the brake fluid pressure in the wheel cylinder device. A malfunction position/mode detecting unit detects a malfunction position and a malfunction mode in the hydraulic brake pressure control system based on the signal output by the wheel cylinder sensor device during the master cylinder control and the signal output by the wheel cylinder sensor device during the brake-by-wire control.

Hydraulic brake pressure control system

A braking pressure control apparatus for a hydraulically operated brake, including a first hydraulic system having a first hydraulic pressure source power-operated to pressurize a working fluid and capable of controlling the fluid pressure, for operating the brake, a second hydraulic system having a second hydraulic pressure source operable by an operating force acting on a manually operable brake operating member, to pressurize the working fluid to a pressure higher than a level corresponding to the operating force, for operating the brake, a switching device operable to selectively establish a first state in which the brake is operated with the pressurized fluid delivered from the first hydraulic pressure source, and a second state in which the brake is operated with the pressurized fluid delivered from the second hydraulic pressure source, and a diagnosing device operable to diagnose the second hydraulic system on the basis of the fluid pressure in the second hydraulic system.

Braking pressure control apparatus having device for diagnosing manually operated hydraulic system

A braking system including a brake cylinder, a first hydraulic pressure source having a first pump device for pressurizing a working fluid, a second hydraulic pressure source operable in response to an operation of a brake operating member, to pressurize the fluid to a pressure higher than a value corresponding to an operating force of the brake operating member, and a brake-cylinder-pressure control device operable when the brake cylinder is disconnected from the second hydraulic pressure source, to control the pressure of the fluid pressurized by the first hydraulic pressure source, such that the fluid pressure in the brake cylinder is controlled to a value determined on the basis of the operating force, and wherein an emergency communication device is operated when at least one of the brake-cylinder-pressure control device and the first pump device fails to normally function, to hold the brake cylinder in communication with the second hydraulic pressure source.

Braking system wherein brake cylinder is communicated with pedal-operated pressure source upon failure of pump-operated pressure source

Vehicle hydraulic braking system including a hydraulic pressure source for pressurizing a fluid according to an operation of a brake operating member, so that the pressurized fluid is supplied to at least one wheel brake cylinder for braking at least wheel of the vehicle, a pressure control valve device for regulating the pressure of the fluid to be applied to each wheel brake cylinder, the valve device having a pressure-increasing, pressure-holding and pressure-reducing states, and a reservoir for storing the fluid which has been discharged from each wheel brake cylinder through the pressure control valve device during the operation of the brake operating member, so that the fluid is returned from the reservoir to the hydraulic pressure source after the operation of the brake operating member. The reservoir has a storage capacity smaller than a maximum total amount of the fluid that can be accommodated in all of the at least one wheel brake cylinder during operation of the at least one wheel brake cylinder.

Vehicle hydraulic braking system having reservoir for storing fluid

In a hydraulic brake device, a pressurizing chamber receives a master cylinder pressure generated by a master cylinder. A pressure adjusting chamber receives an accumulator pressure generated by a high pressure source. A booster piston is movably provided between the pressurizing chamber and the pressure adjusting chamber. The booster piston is actuated in a first direction away from the pressurizing chamber by a pressure in the pressurizing chamber and actuated in a direction opposite to the first direction by a pressure in the pressure adjusting chamber. A flow control mechanism responsive to a movement of the booster piston is provided. The flow control mechanism makes the pressure adjusting chamber open to the high pressure source when the booster piston is moved in the first direction exceeding a predetermined distance, and closes the pressure adjusting chamber to be cut off from the high pressure source when the booster piston is moved in the opposite direction back to an initial position. The hydraulic brake device allows a boosted pressure in the pressure adjusting chamber to be produced based on the accumulator pressure when a malfunction in an electrical system is detected, and supplies the boosted pressure into a wheel cylinder.

Hydraulic brake device

In a brake fluid control device, front wheel cylinders are connected to a front hydraulic circuit, and rear wheel cylinders are connected to a rear hydraulic circuit. The front hydraulic circuit and the rear hydraulic circuit are connected to a front left pressure-decrease valve, a front right pressure-decrease valve, a rear left pressure-decrease valve, a rear right pressure-decrease valve and a connecting pipe. When a brake pedal is depressed, the front left pressure-decrease valve, the front right pressure-decrease valve, the rear left pressure-decrease valve and the rear right pressure-decrease valve are opened and a master cylinder pressure sensor leads to both the front hydraulic circuit and the rear hydraulic circuit. Comparing a detection value of the of the master cylinder pressure sensor, a detection value of a front wheel cylinder pressure sensor and a detection value of a rear wheel cylinder pressure sensor respectively, detects the state of operation of each of the sensors provided in the system.

Brake fluid pressure control device

A brake fluid pressure control apparatus achieves a sufficiently large brake force even when a malfunction occurs in an operational force sensor for detecting a level of operational force applied to a brake system. A magnitude of a master cylinder pressure generated by a master cylinder is detected by a master cylinder pressure sensor. A linear fluid pressure source generates a linear fluid pressure adjusted by the magnitude of the master cylinder pressure. Front wheel cylinders and rear wheel cylinders are provided with the linear fluid pressure. A front wheel cylinder pressure is detected and a front wheel cylinder pressure value corresponding to a magnitude of the front wheel cylinder pressure is output by a front wheel cylinder sensor. If it is determined that a malfunction is occurring in the operational force sensor, a connection of the front wheel cylinders is switched from the linear fluid pressure source to the master cylinder. At this time, the linear fluid pressure source is controlled based on the front wheel cylinder pressure value.

Brake fluid pressure control apparatus for compensating a malfunction of

A hydraulic brake control apparatus in which a master cylinder supplies a brake fluid pressure responsive to a brake operating force to wheel cylinders through a first valve, includes a first control unit which controls second valves and third valves when a brake fluid pressure supplied to the wheel cylinders by a pressure supplying device is detected to be excessively high under a condition in which the supply of the brake fluid pressure to the wheel cylinders by the master cylinder is inhibited by the first valve, so that the supply of the brake fluid pressure to the wheel cylinders by the pressure supplying device is inhibited by the second valves and a flow of the brake fluid from the wheel cylinders into a reservoir tank is allowed by the third valves. A second control unit controls the third valves and the first valve at a predetermined time after the flow of the brake fluid from the wheel cylinders into the reservoir tank is allowed, so that the flow of the brake fluid from the wheel cylinders into the reservoir tank is inhibited by the third valves and the supply of the brake fluid pressure to the wheel cylinders by the master cylinder is allowed by the first valve.

Hydraulic brake control apparatus

Hydraulic pressure control apparatus wherein a pressure difference across a seating valve disposed in a fluid passage acts on a valve member for placing the seating valve in an open state, while an elastic member biases the valve member for placing the seating valve in a closed state, and a valve driving device operated with an electric current applied thereto generates a drive force acting on the valve member so as to open the seating valve. A control device for controlling the electric current includes a stepping controller for incrementing the amount of the electric current when the seating valve is operated from the closed state into the open state, such that an increment of the electric current decreases with an increase in the pressure difference. The hydraulic pressure control apparatus may be suitably used in a vehicle braking system, for controlling fluid pressure in wheel brake cylinder.

Pressure control apparatus including seating valve controlled by

A hydraulic brake control apparatus includes a pressure supply inhibiting unit which inhibits supply of a brake fluid pressure to wheel cylinders by a first pressure supplying unit when a defect in a brake fluid path between a first flow control unit and the wheel cylinders has occurred, and inhibits supply of a brake fluid pressure to the wheel cylinders by a second pressure supplying unit when a defect in a brake fluid path between a second flow control unit and the wheel cylinders has occurred. A pressure supply path control unit controls the first and second flow control units when a defect in one of a first brake fluid path between the first pressure supplying unit and the first flow control unit and a second brake fluid path between the second pressure supplying unit and the second flow control unit has occurred, such that a flow of the brake fluid from one of the first and second pressure supplying units connected to the defective path, into the wheel cylinders is inhibited, and a flow of the brake fluid from the other of the first and second pressure supplying units connected to the other path, into the wheel cylinders is allowed to supply the brake fluid pressure from the other pressure supplying unit to the wheel cylinders through the other path.

A hydraulic brake control apparatus in which a master cylinder is connected to wheel cylinders via a master cylinder cut valve, and the wheel cylinders are connected to a reservoir tank via a switching valve, includes a check valve provided between the master cylinder and the wheel cylinders in parallel with the master cylinder cut valve, the check valve provided in a bypass passage of the master cylinder cut valve, the check valve allowing a flow of a brake fluid from the master cylinder to the wheel cylinders and inhibiting a flow of the brake fluid from the wheel cylinders to the master cylinder. A valve control unit controls the switching valve when it is detected that a closed-position defect in the master cylinder cut valve has occurred and a pressure of the brake fluid in the master cylinder is decreasing, so that the switching valve is set at an open position to allow a flow of the brake fluid from the wheel cylinders to the reservoir tank through the switching valve and reduce a pressure of the brake fluid in the wheel cylinders.

A brake apparatus for an electric vehicle which maintains the regenerative energy generated in a traction motor of each of wheels to be at a maximum. A hydraulic pressure brake and a regenerative brake are provided in the same brake apparatus. The hydraulic pressure brake generates a brake torque by providing a hydraulic pressure to a wheel cylinder of each wheel of the vehicle. The regenerative brake generates a brake torque by regeneration in a traction motor for each wheel. The brake torque to be provided is calculated for each wheel. A maximum regenerative energy is calculated for each wheel. A hydraulic pressure calculating unit calculates a hydraulic pressure to be provided to the wheel cylinder of each wheel based on the brake torque and the maximum regenerative energy so that the regenerative energy generated by the traction motor of each wheel becomes a maximum. The hydraulic pressure calculated by the hydraulic pressure calculating unit is provided to the wheel cylinder of a corresponding wheel by a hydraulic pressure control valve which generates the hydraulic pressure by reducing a master cylinder pressure.

Brake apparatus for an electric vehicle to maximize regenerative energy

A hydraulic brake system is provided which does not need a mechanism to feed back the wheel cylinder pressure. The hydraulic brake system generates a brake force by supplying the brake fluid to a wheel cylinder under a high pressure generated by a high pressure source. The brake fluid is supplied to the high pressure source from a reservoir tank storing the brake fluid under atmospheric pressure. A fluid passage connects the high pressure source to both the wheel cylinder and the reservoir tank. An amount of the brake fluid flowing from the high pressure source to the wheel cylinder is controlled by a constant flow valve.

Hydraulic brake system for controlling fluid flow to a wheel cylinder

A hydraulic brake apparatus includes a control valve having a spool which is bi-directionally movable between a first position and a second position, the spool, when located at the first position, allowing brake fluid from a low-pressure source to pass through the control valve to a wheel cylinder, and the spool, when located at the second position, allowing brake fluid from a high-pressure source to pass through the control valve to the wheel cylinder. A first unit introduces brake fluid from the wheel cylinder into the control valve, the brake fluid having a wheel cylinder pressure exerted to move the spool in a first direction toward the first position. A second unit introduces brake fluid from a master cylinder into the control valve, the brake fluid having a master cylinder pressure exerted to move the spool in a second, reverse direction toward the second position. A third unit reduces the master cylinder pressure exerted on the spool.

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Toyota, Japan

Fumiaki Kawahata