Modular hydraulic valve assembly for work vehicle

1. A hydraulic valve assembly for use in a vehicle, the vehicle including:

a plurality of wheels;

a cooling fan;

equipment for carrying out a work function of the vehicle,

a plurality of hydraulic circuits; and

first and second hydraulic pumps for supplying hydraulic pressure to the hydraulic circuits, wherein:

the hydraulic circuits comprise:

first and second service brake circuits, wherein each service brake circuit comprises at least one respective service brake actuator for braking the wheels;

a fan circuit including a fan actuator for operating the cooling fan;

a steering circuit including at least one steering actuator for steering the wheels; and

a work function circuit including at least one equipment actuator for operating the equipment;

the valve assembly comprises:

a fan and brake function module configured to control a supply of hydraulic pressure to the fan circuit and the service brake circuits; and

a steering and work function module configured to control a supply of hydraulic pressure to the steering circuit and the work function circuit;

the fan and brake function module comprises:

a first pump inlet for receiving a supply of hydraulic pressure from the first pump;

first and second service brake outlets for supplying hydraulic pressure to the first and second service brake circuits; and

a fan supply outlet for supplying hydraulic pressure to the fan circuit;

the steering and work function module comprises:

a second pump inlet for receiving a supply of hydraulic pressure from the second pump;

a steering supply outlet for supplying hydraulic pressure to the steering circuit of the vehicle; and

a work function outlet for supplying hydraulic pressure to the work function circuit of the vehicle;

and wherein:

the fan and brake function module has a first interface surface and a plurality of first ports opening through the first interface surface;

the steering and work function module has a second interface surface and a plurality of second ports opening through the second interface surface; and

the fan and brake function module and the steering and work function module are separable at the first and second interface surfaces, and are connectable together at the first and second interface surfaces in a connected configuration in which each of the first ports is in fluid communication with a respective one of the second ports.

2. A hydraulic valve assembly according to claim 1 , wherein the steering and work function module includes a steering function priority valve configured to restrict the supply of hydraulic pressure from the second pump to the work function outlet to maintain the supply of hydraulic pressure from the second pump to the steering supply outlet, responsive to increasing load on the steering circuit.

3. A hydraulic valve assembly according to claim 2 , wherein:

the steering and work function module is configured to control a supply of hydraulic pressure from both of the first and second pumps to the work function outlet;

the steering and work function module includes a fan and brake function priority valve configured to restrict the supply of hydraulic pressure from the first pump to the work function outlet to maintain the supply of hydraulic pressure from the first pump to the first and second service brake outlets and the fan supply outlet, responsive to increasing load on any of the fan circuit and the first and second service brake circuits; and

the first and second ports include first and second work function supply ports configured in fluid communication in the connected configuration to convey the hydraulic pressure from the first pump inlet of the fan and brake function module to the fan and brake function priority valve of the steering and work function module.

4. A hydraulic valve assembly according to claim 3 , wherein:

the fan and brake function module is configured to generate a first load sensing pressure signal indicative of variations in load on the fan circuit and the first and second service brake circuits;

the first and second ports include first and second load sensing pressure signal ports configured in fluid communication in the connected configuration to convey the first load sensing pressure signal from the fan and brake function module to the fan and brake function priority valve of the steering and work function module;

the fan and brake function priority valve being operable responsive to the first load sensing pressure signal to restrict the supply of hydraulic pressure from the first pump to the work function outlet to maintain the supply of hydraulic pressure from the first pump to the first and second service brake outlets and the fan supply outlet.

5. A hydraulic valve assembly according to claim 1 , further including a work control module configured to control operation of the work function circuit, wherein

the steering and work function module includes a third interface surface and a plurality of third ports opening through the third interface surface;

the work control module has a fourth interface surface and a plurality of fourth ports opening through the fourth interface surface; and

the steering and work function module and the work control module are separable at the third and fourth interface surfaces and are connectable together at the third and fourth interface surfaces in a connected configuration in which each of the third ports is in fluid communication with a respective one of the fourth ports.

6. A hydraulic valve assembly according to claim 5 , wherein:

the work control module includes a work function control valve assembly operable by a work function pilot pressure supply (P 1 ) responsive to a work function control signal (S 3 ) to control the operation of the at least one equipment actuator in the work function circuit; and

a flowpath is provided in the steering and work function module between the second interface surface and the third interface surface to convey the work function pilot pressure supply (P 1 ) from the fan and brake function module to the work function control valve assembly of the work control module.

7. A hydraulic valve assembly according to claim 5 , further including an auxiliary module configured to control a supply of hydraulic pressure to at least one further hydraulic circuit of the vehicle, wherein:

the fan and brake function module includes a fifth interface surface and a plurality of fifth ports opening through the fifth interface surface;

the auxiliary module includes:

at least one auxiliary supply outlet for supplying hydraulic pressure to the at least one further hydraulic circuit of the vehicle; and

a sixth interface surface and a plurality of sixth ports opening through the sixth interface surface;

the auxiliary module and the fan and brake function module are separable at the fifth and sixth interface surfaces and are connectable together at the fifth and sixth interface surfaces in a connected configuration in which each of the fifth ports is in fluid communication with a respective one of the sixth ports; and

the fan and brake function module are configured to supply pressure from the first pump inlet to the at least one auxiliary supply outlet via respective ones of the fifth and sixth ports in the connected configuration.

8. A hydraulic valve assembly according to claim 7 , wherein both of the first and fifth interface surfaces are formed on a valve block of the fan and brake function module, and both of the second and third interface surfaces are formed on a valve block of the steering and work function module.

9. A hydraulic valve assembly according to claim 8 , wherein the auxiliary module comprises a third service brake outlet for supplying hydraulic pressure to one of the first and second service brake circuits, and wherein one of the first and second service brake outlets is configured as one of the fifth ports being in fluid communication with the third service brake outlet in the connected configuration through a flowpath formed in a valve block of the auxiliary module.

10. A hydraulic valve assembly according to claim 8 , wherein:

at least one of the valve block of the fan and brake function module and the valve block of the steering and work function module defines internal hydraulic flowpaths formed by casting; and

the sixth interface surface is formed on a valve block of the auxiliary module, the valve block of the auxiliary module defining internal hydraulic flowpaths formed by machining and not by casting.

11. A hydraulic valve assembly according to claim 10 , wherein:

the auxiliary module comprises a third service brake outlet for supplying hydraulic pressure to one of the first and second service brake circuits; and

one of the first and second service brake outlets is configured as one of the fifth ports being in fluid communication with the third service brake outlet in the connected configuration, through a flowpath formed by machining in the valve block of the auxiliary module.