A hydraulic brake mechanism is mountable to a bicycle handlebar. The hydraulic brake mechanism includes a housing having a base portion and an extension portion, the base portion including first and second ends, the base portion including a handlebar clamp at the first end, the base portion extending generally horizontally and the extension portion extending forwardly of the base portion at the second end and angled generally upwardly from the base portion when the hydraulic brake mechanism is mounted to the bicycle handlebar, the housing sized and shaped to be grasped by a user's hand, the housing having a fluid outlet port in the extension portion. The hydraulic brake mechanism may include a fluid line attached to the fluid outlet port and disposed in a groove formed along a length of the extension portion and the base portion of the housing.

A hydraulic brake mechanism is mountable to a bicycle handlebar. The hydraulic brake mechanism includes a housing having a base portion and an extension portion, the base portion including first and second ends, the base portion including a handlebar clamp at the first end, the base portion extending generally horizontally and the extension portion extending forwardly of the base portion at the second end and angled generally upwardly from the base portion when the hydraulic brake mechanism is mounted to the bicycle handlebar, the housing sized and shaped to be grasped by a user's hand, the housing having a fluid outlet port in the extension portion. The hydraulic brake mechanism may include a fluid line attached to the fluid outlet port and disposed in a groove formed along a length of the extension portion and the base portion of the housing.

A hydraulic actuator which may be used as a surge brake actuator may include a housing defining a low pressure chamber and a high pressure chamber, a low pressure piston assembly which is in the low pressure chamber and has a contact surface, a high pressure piston assembly which is in the high pressure chamber and which moves forward in response to forward movement of the low pressure piston assembly, and an unloader valve in fluid communication with the low pressure chamber and having a closed position and an open position adapted to allow hydraulic fluid to flow out of the low pressure chamber through the unloader valve, wherein the contact surface engages and pushes the unloader valve from the closed position to the open position during forward movement of the low pressure piston assembly. The actuator may be used for actuating a brake system.

A hydraulic actuator which may be used as a surge brake actuator may include a housing defining a low pressure chamber and a high pressure chamber, a low pressure piston assembly which is in the low pressure chamber and has a contact surface, a high pressure piston assembly which is in the high pressure chamber and which moves forward in response to forward movement of the low pressure piston assembly, and an unloader valve in fluid communication with the low pressure chamber and having a closed position and an open position adapted to allow hydraulic fluid to flow out of the low pressure chamber through the unloader valve, wherein the contact surface engages and pushes the unloader valve from the closed position to the open position during forward movement of the low pressure piston assembly. The actuator may be used for actuating a brake system.

The brake device for a vehicle generates two master pressures by controlling one single servo pressure to accurately control braking force. The pressure increasing characteristic is set based on the first pressure increasing characteristic obtained from the relationship between the servo pressure and the first master pressure upon increasing the servo pressure and the second pressure increasing characteristic obtained from the servo pressure and the second master pressure. The pressure decreasing characteristic is set based on the first pressure increasing characteristic obtained from the relationship between the servo pressure and the first master pressure upon decreasing the servo pressure and the second pressure decreasing characteristic obtained from the servo pressure and the second master pressure. Thus, the total braking force of the brake device is the sum of a braking force generated by the first master pressure and a braking force generated by the second master piston.

The brake device for a vehicle generates two master pressures by controlling one single servo pressure to accurately control braking force. The pressure increasing characteristic is set based on the first pressure increasing characteristic obtained from the relationship between the servo pressure and the first master pressure upon increasing the servo pressure and the second pressure increasing characteristic obtained from the servo pressure and the second master pressure. The pressure decreasing characteristic is set based on the first pressure increasing characteristic obtained from the relationship between the servo pressure and the first master pressure upon decreasing the servo pressure and the second pressure decreasing characteristic obtained from the servo pressure and the second master pressure. Thus, the total braking force of the brake device is the sum of a braking force generated by the first master pressure and a braking force generated by the second master piston.

A rotating pumping apparatus is provided which may be employed in an automotive brake system. The rotating pumping apparatus includes a sealing member and a pressure member. The sealing member is disposed around a pump drive shaft. The pressure member includes a plate spring, a first rotation stopper, and a second rotation stopper. The first rotation stopper serves to stop the pressure member from rotating following rotation of the pump drive shaft. The second rotation stopper engages the seal ring to stop the sealing member from rotating following the rotation of the pump drive shaft. The plate spring works to elastically press the sealing member against a stopper wall of a pump casing to stop the sealing member from moving in an axial direction of the pump drive shaft.

A rotating pumping apparatus is provided which may be employed in an automotive brake system. The rotating pumping apparatus includes a sealing member and a pressure member. The sealing member is disposed around a pump drive shaft. The pressure member includes a plate spring, a first rotation stopper, and a second rotation stopper. The first rotation stopper serves to stop the pressure member from rotating following rotation of the pump drive shaft. The second rotation stopper engages the seal ring to stop the sealing member from rotating following the rotation of the pump drive shaft. The plate spring works to elastically press the sealing member against a stopper wall of a pump casing to stop the sealing member from moving in an axial direction of the pump drive shaft.

An object of the present invention is to provide a brake apparatus that can achieve a characteristic capable of increasing a pressure with high responsiveness without relying on a discharge capability of a pump. According to an aspect of the present invention, a brake apparatus includes an operation rod configured to be activated according to an operation of a brake operation member and having a first diameter, a stepped piston including an intermediate-diameter portion having a larger diameter than the first diameter on one side, a large-diameter portion having a larger diameter than the diameter of the intermediate-diameter portion, and an insertion hole in which the operation rod is relatively displaceably inserted from an axial direction, a first pressure chamber formed between the first diameter and the intermediate-diameter portion, and a second pressure chamber formed between the intermediate-diameter portion and the large-diameter portion. The brake apparatus controls an amount of the brake fluid to be supplied to the first pressure chamber and the second pressure chamber, and increases the amount of the brake fluid to be supplied to the second pressure chamber when a detected state is a pressure increase request requiring high responsiveness.

An object of the present invention is to provide a brake apparatus that can achieve a characteristic capable of increasing a pressure with high responsiveness without relying on a discharge capability of a pump. According to an aspect of the present invention, a brake apparatus includes an operation rod configured to be activated according to an operation of a brake operation member and having a first diameter, a stepped piston including an intermediate-diameter portion having a larger diameter than the first diameter on one side, a large-diameter portion having a larger diameter than the diameter of the intermediate-diameter portion, and an insertion hole in which the operation rod is relatively displaceably inserted from an axial direction, a first pressure chamber formed between the first diameter and the intermediate-diameter portion, and a second pressure chamber formed between the intermediate-diameter portion and the large-diameter portion. The brake apparatus controls an amount of the brake fluid to be supplied to the first pressure chamber and the second pressure chamber, and increases the amount of the brake fluid to be supplied to the second pressure chamber when a detected state is a pressure increase request requiring high responsiveness.