The present disclosure is directed to a braking system for a work vehicle having hydraulically-actuated brakes. The braking system includes a primary release valve, a secondary release valve, and at least one braking mechanism having one or more brake springs. The braking mechanism(s) is hydraulically coupled to the primary release valve and the secondary release valve via one or more hydraulic lines. As such, during full-power operation of the work vehicle, when the brakes are to be released, the primary release valve is energized so as to overcome a valve biasing spring, thereby shifting the primary release valve so as to direct pressurized hydraulic fluid to the braking mechanism(s). Further, when the brakes are to be applied, the primary release valve is inactive so as to allow the hydraulic fluid to flow away from the braking mechanism(s) to a primary reservoir such that the one or more brake springs compress the braking mechanism(s). Alternatively, when power is lost to the work vehicle, the secondary release valve bypasses the primary release valve and directs pressurized hydraulic fluid to the braking mechanism(s) to release the brakes.

The present disclosure is directed to a braking system for a work vehicle having hydraulically-actuated brakes. The braking system includes a primary release valve, a secondary release valve, and at least one braking mechanism having one or more brake springs. The braking mechanism(s) is hydraulically coupled to the primary release valve and the secondary release valve via one or more hydraulic lines. As such, during full-power operation of the work vehicle, when the brakes are to be released, the primary release valve is energized so as to overcome a valve biasing spring, thereby shifting the primary release valve so as to direct pressurized hydraulic fluid to the braking mechanism(s). Further, when the brakes are to be applied, the primary release valve is inactive so as to allow the hydraulic fluid to flow away from the braking mechanism(s) to a primary reservoir such that the one or more brake springs compress the braking mechanism(s). Alternatively, when power is lost to the work vehicle, the secondary release valve bypasses the primary release valve and directs pressurized hydraulic fluid to the braking mechanism(s) to release the brakes.

A method of controlling deceleration of a vehicle which includes the steps of sensing the speed of rotation of the output shaft and generating an output shaft speed signal. The method also includes deriving from the output shaft speed signal a deceleration signal indicative of deceleration of the vehicle, and generating in accordance with a selectively effective feedback control scheme a braking command. The method further includes using the output shaft speed signal to calculate a maximum braking power signal and modulating the braking command in dependence on the maximum braking power signal in order to limit the braking power applied in the SAHR brake. The maximum braking power signal is determined in dependence on the heat dissipating capacity of the SAHR brake and is such as to give rise to a constant or approximately constant value of braking power dissipated in the SAHR brake.

A method of controlling deceleration of a vehicle which includes the steps of sensing the speed of rotation of the output shaft and generating an output shaft speed signal. The method also includes deriving from the output shaft speed signal a deceleration signal indicative of deceleration of the vehicle, and generating in accordance with a selectively effective feedback control scheme a braking command. The method further includes using the output shaft speed signal to calculate a maximum braking power signal and modulating the braking command in dependence on the maximum braking power signal in order to limit the braking power applied in the SAHR brake. The maximum braking power signal is determined in dependence on the heat dissipating capacity of the SAHR brake and is such as to give rise to a constant or approximately constant value of braking power dissipated in the SAHR brake.

A power brake system (1.1) of a vehicle (2) has a pressure medium source (14) and a pressure-medium-operated primary brake system (30) operable as a service brake and steering brake system. The primary brake system has at least one foot brake valve (36a, 36b) and two wheel brake cylinders (40a, 40b) arranged on both sides on a drive axle (8) and operable independently of one another. A pressure-medium-operated secondary brake system (50), operable independently of the primary brake system (30), has a brake control valve (56) and at least one brake cylinder (62a, 62b. The secondary brake system (50) is electronically controllable and has a brake control valve (56) configured as a solenoid valve. The braking force of the at least one brake cylinder (62a, 62b) can be set by feeding or removing pressure medium to or from the latter via the brake control valve (56).

A power brake system (1.1) of a vehicle (2) has a pressure medium source (14) and a pressure-medium-operated primary brake system (30) operable as a service brake and steering brake system. The primary brake system has at least one foot brake valve (36a, 36b) and two wheel brake cylinders (40a, 40b) arranged on both sides on a drive axle (8) and operable independently of one another. A pressure-medium-operated secondary brake system (50), operable independently of the primary brake system (30), has a brake control valve (56) and at least one brake cylinder (62a, 62b. The secondary brake system (50) is electronically controllable and has a brake control valve (56) configured as a solenoid valve. The braking force of the at least one brake cylinder (62a, 62b) can be set by feeding or removing pressure medium to or from the latter via the brake control valve (56).

A relay valve module for an electronically controllable pneumatic brake system for actuating wheel brakes of a utility vehicle includes: a reservoir connection for receiving a reservoir pressure; a brake control pressure connection for receiving a brake control pressure; at least one first service brake connection for outputting a service brake pressure; a relay valve with a relay valve reservoir connection, which is connected to the reservoir connection, a relay valve working connection, which is connected to the first service brake connection, a relay valve ventilation connection, and a relay valve control connection; an electropneumatic pilot control unit, which is connected to the reservoir connection, the electropneumatic pilot control unit providing a pilot control pressure; and a shuttle valve with a first shuttle valve inlet, a second shuttle valve inlet, and a shuttle valve outlet. The first shuttle valve inlet is connected to the brake control pressure connection.

The present invention relates to an electronic parking brake device for a vehicle, in particular a utility vehicle. As a function of at least one operating state of a towing vehicle parking brake supply line and/or a trailer parking brake supply line, a towing vehicle parking brake control valve is activatable by a control unit in such a way that a towing vehicle parking brake supply line can be deaerated or aerated by the towing vehicle parking brake control valve. By manually actuating a trailer parking brake control element, a trailer parking brake control valve is activatable by the control unit in such a way that a trailer parking brake supply line can be deaerated or aerated by the trailer parking brake control valve. The present invention also relates to a method for operating the above electronic parking brake device for a vehicle.

A work vehicle includes a vehicle body frame, an electric motor supported by the vehicle body frame, a power transmission mechanism including a drive shaft connected to an output shaft of the electric motor to transmit power generated by the electric motor to a wheel on which a tire is mounted, a supporting member supported by the vehicle body frame to rotatably support the drive shaft, and a parking brake provided on an outside of the supporting member to restrict a rotation of the drive shaft.

A work vehicle includes a vehicle body frame, an electric motor supported by the vehicle body frame, a power transmission mechanism including a drive shaft connected to an output shaft of the electric motor to transmit power generated by the electric motor to a wheel on which a tire is mounted, a supporting member supported by the vehicle body frame to rotatably support the drive shaft, and a parking brake provided on an outside of the supporting member to restrict a rotation of the drive shaft.