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 pressure-limiting valve includes a housing having a piston, a pressure-limiting adjusting spring, at least one inlet and at least one outlet. The piston can assume an open position in which the inlet and the outlet are connected to each other, and at least one closed position in which the inlet and the outlet are separated from each other. The piston has a first piston ring with a sealing surface and a second piston ring. In the closed position, the sealing surface is drawn against a housing projection in a sealing manner by a pneumatic force which acts on the second piston ring and is directed against the force of the pressure-limiting adjusting spring. A pneumatic passage in the piston which implements a safety valve function can be sealed by a spring-loaded safety valve body arranged on a side of the second piston ring that is opposite the outlet.

A pressure-limiting valve includes a housing having a piston, a pressure-limiting adjusting spring, at least one inlet and at least one outlet. The piston can assume an open position in which the inlet and the outlet are connected to each other, and at least one closed position in which the inlet and the outlet are separated from each other. The piston has a first piston ring with a sealing surface and a second piston ring. In the closed position, the sealing surface is drawn against a housing projection in a sealing manner by a pneumatic force which acts on the second piston ring and is directed against the force of the pressure-limiting adjusting spring. A pneumatic passage in the piston which implements a safety valve function can be sealed by a spring-loaded safety valve body arranged on a side of the second piston ring that is opposite the outlet.

A redundant governor apparatus is provided for a vehicle air brake charging system. The apparatus comprises a first governor and a second governor. The apparatus also comprises a number of components arranged to enable (i) the first governor to act as primary and the second governor to act as backup to the first governor when the first governor is unable to act as primary, and (ii) the second governor to act as primary and the first governor to act as backup to the second governor when the second governor is unable to act as primary.

A redundant governor apparatus is provided for a vehicle air brake charging system. The apparatus comprises a first governor and a second governor. The apparatus also comprises a number of components arranged to enable (i) the first governor to act as primary and the second governor to act as backup to the first governor when the first governor is unable to act as primary, and (ii) the second governor to act as primary and the first governor to act as backup to the second governor when the second governor is unable to act as primary.

A system for delivering fluid in a machine is provided. The system includes a pump, a first valve disposed downstream of the pump, a check valve disposed downstream of the first valve, at least one accumulator disposed downstream of the check valve, and an auxiliary system disposed upstream of the check valve. The system further includes a control unit configured to receive a signal indicative of a fluid demand from the auxiliary system. The control unit is also configured to selectively control the first valve in a first position to limit flow of the fluid from the pump to the auxiliary system, and in a second position to allow flow of the fluid from the pump to the auxiliary system based, at least in part, on the received signal. The check valve limits flow of a fluid from the at least one accumulator to the auxiliary system.

A system for delivering fluid in a machine is provided. The system includes a pump, a first valve disposed downstream of the pump, a check valve disposed downstream of the first valve, at least one accumulator disposed downstream of the check valve, and an auxiliary system disposed upstream of the check valve. The system further includes a control unit configured to receive a signal indicative of a fluid demand from the auxiliary system. The control unit is also configured to selectively control the first valve in a first position to limit flow of the fluid from the pump to the auxiliary system, and in a second position to allow flow of the fluid from the pump to the auxiliary system based, at least in part, on the received signal. The check valve limits flow of a fluid from the at least one accumulator to the auxiliary system.

A pressure-limiting valve has a valve housing, a piston, a pressure-limiting adjustment spring, at least one inlet and at least one outlet. The piston can assume an open position in which the inlet and the outlet are connected to each other and a closed position which separates the inlet and outlet. A first piston ring has a sealing surface and has a small pneumatic active surface relative to a second piston ring. Between the first and second piston rings the piston has a substantially truncated cone-like portion which tapers toward the first piston ring. In the closed position, the sealing surface of the first piston ring is sealingly drawn against a housing collar by a pneumatic force acting counter to the force of the pressure-limiting adjustment spring. A pneumatic passage for creating a safety valve function closable by a spring-loaded safety valve body is provided in the piston.

A pressure-limiting valve includes a housing having a piston, a pressure-limiting adjusting spring, at least one inlet and at least one outlet. The piston can assume an open position in which the inlet and the outlet are connected to each other, and at least one closed position in which the inlet and the outlet are separated from each other. The piston has a first piston ring with a sealing surface and a second piston ring. In the closed position, the sealing surface is drawn against a housing projection in a sealing manner by a pneumatic force which acts on the second piston ring and is directed against the force of the pressure-limiting adjusting spring. A pneumatic passage in the piston which implements a safety valve function can be sealed by a spring-loaded safety valve body arranged on a side of the second piston ring that is opposite the outlet.

A pressure-limiting valve includes a housing having a piston, a pressure-limiting adjusting spring, at least one inlet and at least one outlet. The piston can assume an open position in which the inlet and the outlet are connected to each other, and at least one closed position in which the inlet and the outlet are separated from each other. The piston has a first piston ring with a sealing surface and a second piston ring. In the closed position, the sealing surface is drawn against a housing projection in a sealing manner by a pneumatic force which acts on the second piston ring and is directed against the force of the pressure-limiting adjusting spring. A pneumatic passage in the piston which implements a safety valve function can be sealed by a spring-loaded safety valve body arranged on a side of the second piston ring that is opposite the outlet.