The invention relates to an electronically controllable secondary brake system (46), operated by pressure medium, useable as both as a parking brake system and an auxiliary brake system, with spring brake cylinders (68a, 68b) arranged on wheel brakes of at least one vehicle axle (8), with a directly or indirectly electronically controllable brake control valve (56). The brake force of the spring brake cylinder (68a, 68b) can be reduced by a feed of pressure medium and can be increased by a discharge of pressure medium, and with an electronic brake control unit (48) for controlling the brake control valve (56) dependent on the current value of a brake value signal (SBW). The brake control valve (56) is configured as a 3/3-way proportional valve with a pressure medium inlet, a pressure medium outlet, and a working connector, which is connected via a working line (60, 66) to the spring brake cylinders.

A control system and method control release of a braking device from a wheel or disc. Release of the braking device is slowed or stopped based on a speed at which the braking device is released. The braking device may include a return limiting device through which a rod is configured to move. The return limiting device permits the rod to slide within the return limiting device while the brake pad holder releases from the wheel or disc no faster than a designated speed, but engages and restricts movement of the rod within the return limiting device while the brake pad holder releases from the wheel or disc faster than the designated speed.

A control system and method control release of a braking device from a wheel or disc. Release of the braking device is slowed or stopped based on a speed at which the braking device is released. The braking device may include a return limiting device through which a rod is configured to move. The return limiting device permits the rod to slide within the return limiting device while the brake pad holder releases from the wheel or disc no faster than a designated speed, but engages and restricts movement of the rod within the return limiting device while the brake pad holder releases from the wheel or disc faster than the designated speed.

A parking brake unit of a brake device for braking a wheel includes a first piston having a first engaging part on an inner circumference thereof, the first piston being configured to move in first direction by pressure of the hydraulic fluid supplied to a pressure chamber defined in the back thereof, a first biasing member configured to bias the first piston in second direction, opposite to the first direction, a second piston slidably provided on the inner circumference of the first piston, the second piston having a second engaging part on an outer circumference thereof, and an engaging member configured to cause the first engaging part and the second engaging part to engage with each other, in which the second piston causes a brake lining to move in direction bringing the wheel to be in a braking state, when the first piston moves in the second direction.

A braking system is proposed for a vehicle, in particular a lightweight vehicle, in particular a pedal cycle, comprising a brake device, a mechanical urging device, and a hydraulic urging device, wherein the mechanical urging device and the brake device form a parking brake device, and the hydraulic urging device takes the form of a hydraulically actuable release device for the parking brake device.

A hydraulic control system for control of a hydraulic motor. The hydraulic control system comprises a fluid distribution assembly having a tank, a pump to pump fluid from the tank and a directional valve for distributing pressurised fluid from the pump and to return fluid to the tank; a valve assembly fluidly connected to the directional valve, the valve assembly having a first overcenter valve and a pressure reducing valve wherein a first main line connects the directional valve to the first overcenter valve and wherein a shuttle line connects the pressure reducing valve to the first main line; a hydraulic motor fluidly connected to the valve assembly wherein the first main line connects the hydraulic motor to the first overcenter valve; and a brake assembly fluidly connected to the pressure reducing valve, wherein a drain line connects the pressure reducing valve to the hydraulic motor.

In the event of a malfunction in the supply of hydraulic fluid to the a braking device actuating device a hydraulic system has a manually actuated emergency-operation valve arrangement which is formed in such a way that, after the manual actuation thereof, a fluid connection is created between a steering device actuating device and the a pressure chamber of the braking device actuating device. The emergency-operation valve arrangement has a valve block in which flow paths are formed which can be shut off by means of shut-off screws.

A brake system includes a series of rotors for operatively coupling to a shaft and stators for operatively coupling to a frame. A service brake system includes a singular annular service piston extending continuously around the series of rotors and stators and a parking brake system includes a singular annular parking piston positioned to extend continuously around the series of rotors and stators. The service piston nests with the parking piston, under a spring bias, such that the parking piston and service piston continuously engage together around the series of rotors and stators to thereby create the parking brake forces. Springs act on the parking piston to drive the parking piston and nested service piston to engage for parking brake forces. Pressurization of the parking piston deactuates the nested pistons. Then separate pressurization of fluid acts on the service piston to overcome the spring bias and separate the service piston from the parking piston to create service brake forces.

A brake system includes a series of rotors for operatively coupling to a shaft and stators for operatively coupling to a frame. A service brake system includes a singular annular service piston extending continuously around the series of rotors and stators and a parking brake system includes a singular annular parking piston positioned to extend continuously around the series of rotors and stators. The service piston nests with the parking piston, under a spring bias, such that the parking piston and service piston continuously engage together around the series of rotors and stators to thereby create the parking brake forces. Springs act on the parking piston to drive the parking piston and nested service piston to engage for parking brake forces. Pressurization of the parking piston deactuates the nested pistons. Then separate pressurization of fluid acts on the service piston to overcome the spring bias and separate the service piston from the parking piston to create service brake forces.

Lubricating performance of a parking brake is ensured and fuel efficiency during traveling is improved. A parking brake for braking rotation of an output shaft is disposed around the output shaft rotated by driving force. The output shaft is provided with an axial oil passage, a first discharge hole, and a second discharge hole. The axial oil passage extends in an axial direction of the output shaft. The first discharge hole and the second discharge hole communicate with the axial oil passage and open in an outer circumferential surface of the output shaft at an installation position of the parking brake in the axial direction.