A brake system includes a main brake cylinder and a pedal decoupling unit provided with a holding piston, the first ring surface thereof together with a first primary brake cylinder piston defining a first hydraulic chamber that is hydraulically pressurized with an electrically controllable pressure supply device. In order to improve the pedal characteristics of the brake system, in particular in a brake-by-wire brake system, the holding piston is embodied as a differential piston, the second ring surface thereof defining a second, blockable hydraulic chamber, and a piston effect in the second chamber corresponds to a force that acts counter to the direction of actuation on the holding piston.

Brake system for motor vehicles

A stepwise brake control is automatically performed when TTC obtained according to a relative distance and a relative speed between a vehicle and an object is lower than a predetermined value. For example, a brake force or a brake reduction speed is gradually increased over a plurality of stages in time series. Moreover, a brake force or a brake reduction speed change ratio in the section from the rise point of a brake force or a brake reduction speed at each stage to a predetermined brake force or a brake reduction speed is made a predetermined value or a change process is made a change process along a curved shape defined by a predetermined function. Moreover, at the initial stage when gradually increasing the brake force or the brake reduction speed, an auxiliary brake is used. Alternatively, a caution stage having a brake force or a brake reduction speed smaller than the initial stage is provided at the stage preceding the first stage of the plurality of stages, so that the auxiliary brake is used at this caution stage.

Automatic Brake Control Device

A brake control apparatus for a vehicle employs a pressure-amplifying device (10) which reduces a quantity of brake fluid generating a first brake-fluid pressure in a first conduit (A1) connected to a master cylinder (3), and increases second brake-fluid pressure in a second conduit (A2), applied to a wheel cylinder (4,5) simultaneously with the reduction in brake-fluid quantity in the first conduit (A1). As a result, increase in the first brake-fluid pressure is suppressed even when a driver depress a brake pedal (1) and load to generate the first brake-fluid pressure is alleviated. Additionally, the pressure-amplifying device (10) applies the increased second brake-fluid pressure to the wheel cylinder (4,5). Therefore, it is possible to ensure sufficient braking force.

Brake control apparatus for a vehicle

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. A pressure chamber communicates with the output chamber of the regulation valve to bias the auxiliary piston backward by a pressure in the pressure chamber. The auxiliary piston is biased backward by both the auxiliary pressure in the auxiliary pressure chamber and the pressure in the pressure chamber when both of the hydraulic pressure generator and the regulation valve are a normal condition in which the predetermined pressure can be outputted to the output chamber of the regulation valve, and the auxiliary piston is moved forward by the operation force of the brake pedal to move the master cylinder piston forward when at least one of the hydraulic pressure generator and the regulation valve is an abnormal condition in which the predetermined pressure cannot be outputted to the output chamber of the regulation valve.

Hydraulic brake apparatus for a vehicle

A vehicle brake device having a hydraulic pressure generating source is proposed which can reliably prevent dragging and ensure the initial response of brakes during braking. In a brake fluid supply passage from the master cylinder to the wheel cylinder, a brake fluid circulating passage having a hydraulic pressure generating source is provided. A detector for detecting whether the brake pedal is being operated, and a detector for detecting dragging of the brake pads are provided, and only when dragging is detected while the brake pedal is not being operated, the hydraulic pressure generating source is actuated for a predetermined time with a supply valve provided in the brake fluid circulating passage closed and a return valve open to suck brake fluid in the wheel cylinder and increase the distances between the brake pads and the disk rotor, thereby reliably preventing dragging.

Vehicle brake device

In a hydraulic brake system for a vehicle, the brake fluid in a first wheel brake and the brake fluid in a second wheel brake which are hydraulically connected to a pressure generating chamber of a master cylinder are individually caused to flow into a low back pressure reservoir with the aid of an electromagnetic change-over valve and first and second electromagnetic cut-off valves; and with a pump driven by an electric motor, the brake fluid flowing in the low back pressure reservoir in the above-described manner is caused to flow through a first check valve and a first orifice to the first wheel brake, and through a second check valve and a second orifice to the second wheel brake. With the pump operated, the first and second electromagnetic cut-off valves are individually operated, so that the first and second wheel brakes are individually decreased or reincreased in hydraulic pressure. For traction control, electromagnetic change-over valves provided in bypass passages are operated. Thus, with the system, anti-lock control and traction control can be achieved, and, even when the valves added for traction control become out of order, brake fluid can be supplied to or drawn from the wheel brakes as required.

Hydraulic brake system for vehicle

A brake control apparatus is provided with a simulator for applying a biasing force to a manually operated braking member of a vehicle in response to braking operation. A sensor detects conditions of the vehicle including a braking condition of the vehicle. A first biasing device applies a first biasing force to the manually operated braking member in response to braking operation, and a second biasing device applies a second biasing force, as well. Only one of the first and second biasing devices applies the biasing force to the manually operated braking member when a predetermined condition is detected by the sensor, while both of the first and second biasing devices apply the biasing forces in the normal braking operation. The second biasing device may include a cylinder having a bore defined therein, and a piston slidably received in the bore to define a chamber filled with brake fluid, an elastic member for biasing the piston to expand the chamber, and a reservoir communicated with the chamber of the cylinder for storing the brake fluid drained from the cylinder, and controlled by a controller in response to outputs of the sensor.

Brake control apparatus with a stroke simulator

PROBLEM TO BE SOLVED: To surely supply a hydraulic pressure from a master cylinder to a wheel brake by interposing a hydraulic responding valve device in a hydraulic passage for connecting the master cylinder to the wheel brake. SOLUTION: A hydraulic responding valve device 19 is interposed in a hydraulic passage 20 for connecting a master cylinder 16 to a wheel brake 12. The hydraulic responding valve device 19 allows the master cylinder 16 to communicate with the wheel brake 12 when the master cylinder hydraulic pressure is less than a set value. When the master cylinder hydraulic pressure rises the set value or more by the operation of a brake pedal 13, the hydraulic responding valve device 19 allows only the brake fluid passing from the master cylinder 16 side to the wheel brake 12 side. According to this, a hydraulic pressure can be supplied from the master cylinder 16 to the wheel brake 12 through the hydraulic responding valve 19.

The invention is directed to a hydraulic braking system having a master cylinder (10) in which a first piston and a second piston are slidably disposed to define a first pressure chamber (11) and a second pressure chamber (12). A valve device (24) is provided between the first pressure chamber and a reservoir (20). A first pressure control device (30, 31) is provided between the first pressure chamber and wheel cylinders (38, 39), and a second pressure control device (32, 33) is provided between the second pressure chamber and wheel cylinders (40, 41). A pump (27) is provided in a passage connecting the reservoir and the first pressure control device, and driven to supply a brake pressure from the former to the latter. When the valve device is actuated to block the communication between the first pressure chamber and the reservoir, and the pump is driven, the pressure in the first pressure chamber will be increased to move the second piston, so that the pressure in the second pressure chamber will be increased. Accordingly, the pressure in each wheel cylinder may be controlled by the first or second pressure control device without depressing the brake pedal.

Hydraulic braking system for an automotive vehicle

The hydraulic braking system has a master braking cylinder (10), with a sliding piston (14) displaced in dependence on the depression of the brake pedal (13) and a secondary piston (15) on the opposite side of the first piston to the brake pedal. The pressure chambers (11, 12) defined by the pistons are each coupled to respective wheel brakes via pressure regulators (31, 32; 33, 34), with a valve control for operating a valve (24) selectively opening and closing a connection between the first pressure chamber and a brake fluid reservoir (20).

Hiroshi Toda

Papers

Hydraulic brake system for vehicle

Brake control apparatus with a stroke simulator

Vehicle brake device

Hydraulic braking system for an automotive vehicle

Vehicle hydraulic braking system