Brake modulator for parking brake system of a work vehicle

1. A brake modulator for a parking brake system of a work vehicle, the brake modulator comprising:

a housing extending between a first end and a second end, the housing defining a fluid chamber, an auxiliary chamber, a fluid inlet channel in fluid communication with the fluid chamber, and a fluid outlet channel in fluid communication with the fluid chamber;

a piston disposed within the housing between the fluid chamber and the auxiliary chamber, the piston movable between a first position wherein the fluid chamber has a first volume and a second position wherein the fluid chamber has a second volume greater than the first volume;

a first biasing element providing a biasing force on the piston towards the first position;

a rod extending between a first end disposed within the housing and a second end disposed exterior to the housing;

a handle connected to the second end of the rod, wherein the rod is manually actuatable to move the piston between the first position and the second position; and

a secondary biasing element which connects the rod and piston, wherein the secondary biasing element is disposed within the fluid chamber.

2. The brake modulator of claim 1 , wherein the biasing element is disposed within the auxiliary chamber.

3. The brake modulator of claim 1 , wherein the biasing element is a compression spring.

4. The brake modulator of claim 1 , wherein the first end of the rod is disposed within the fluid chamber.

5. The brake modulator of claim 1 , wherein the rod is movable between a first position wherein the fluid communication between the fluid inlet channel and the fluid chamber is allowed and a second position wherein the fluid communication between the fluid inlet channel and the fluid chamber is blocked.

6. The brake modulator of claim 5 , wherein the movement of the rod between the first position and the second position is independent of the movement of the piston.

7. The brake modulator of claim 1 , wherein the fluid communication between the fluid inlet channel and the fluid chamber is blocked when the piston is in the second position.

8. The brake modulator of claim 1 , wherein the rod comprises an isolator segment and a flow segment, the flow segment configured to allow fluid communication between the fluid inlet channel and the fluid chamber when the piston is in the first position, the isolator segment configured to block fluid communication between the fluid inlet channel and the fluid chamber when the piston is in the second position.

9. A parking brake system for use with a transmission of a work vehicle, the parking brake system comprising:

a braking mechanism housed within the transmission;

a brake actuator, the brake actuator coupled to the braking mechanism to allow the braking mechanism to be actuated between an engaged state and a disengaged state, the brake actuator comprising:

a housing extending between a first end and a second end, the housing defining a second-side chamber and a first-side chamber;

a piston positioned within the housing between the first-side chamber and the second-side chamber, the piston movable between a first position wherein the braking mechanism is actuated to the engaged state and a second position wherein the braking mechanism is actuated to the disengaged state; and

a brake modulator in fluid communication with the brake actuator, the brake modulator comprising:

a housing extending between a first end and a second end, the housing defining a fluid chamber, an auxiliary chamber, a fluid inlet channel in fluid communication with the fluid chamber, and a fluid outlet channel in fluid communication between the fluid chamber and the first-side chamber of the brake actuator;

a piston disposed within the housing between the fluid chamber and the auxiliary chamber, the piston movable between a first position wherein the fluid chamber has a first volume and a second position wherein the fluid chamber has a second volume greater than the first volume;

a biasing element providing a biasing force on the piston towards the first position;

a rod extending between a first end disposed within the housing and a second end disposed exterior to the housing; and

a handle connected to the second end of the rod,

wherein the rod is manually actuatable to move the piston between the first position and the second position, and

wherein movement of the piston of the brake modulator to the second position causes movement of the piston of the brake actuator to the first position and movement of the piston of the brake modulator to the first position causes movement of the piston of the brake actuator to the second position.

10. The parking brake system of claim 9 , wherein the biasing element is disposed within the auxiliary chamber.

11. The parking brake system of claim 9 , wherein the biasing element is a compression spring.

12. The parking brake system of claim 9 , further comprising a secondary biasing element connecting the rod and the piston.

13. The parking brake system of claim 12 , wherein the secondary biasing element is disposed within the fluid chamber.

14. The parking brake system of claim 12 , wherein the rod is movable between a first position wherein the fluid communication between the fluid inlet channel and the fluid chamber is allowed and a second position wherein the fluid communication between the fluid inlet channel and the fluid chamber is blocked.

15. The parking brake system of claim 14 , wherein the movement of the rod between the first position and the second position is independent of the movement of the piston.

16. The parking brake system of claim 9 , wherein the fluid communication between the fluid inlet channel and the fluid chamber is blocked when the piston is in the second position.

17. The parking brake system of claim 16 , wherein the rod comprises an isolator segment and a flow segment, the flow segment configured to allow fluid communication between the fluid inlet channel and the fluid chamber when the piston is in the first position, the isolator segment configured to block fluid communication between the fluid inlet channel and the fluid chamber when the piston is in the second position.