Quick drain, low mess, hydrostatic transmission filter and plug assembly

1. A filter component comprising:

a cartridge portion including a filter media for filtering a fluid and defining a fluid flow path for fluid being filtered; and

a plug assembly on which the cartridge portion is mounted and in fluid communication with the cartridge portion;

wherein:

the plug assembly comprises a first plug and a second plug, the first plug being larger than the second plug;

the second plug is fixed to an inner surface of the first plug in an installed state and is removable from the first plug in a draining state;

the first plug defines a first flow path for communicating fluid from the fluid flow path of the cartridge portion to an outside of the filter component; and

the first plug further defines a drain port separate from the first flow path, wherein in the installed state the second plug plugs the drain port and in a draining state the second plug is removed from the first plug to permit draining fluid through the drain port.

2. The filter component of claim 1 , wherein an outer surface of the second plug has a threaded portion and a step portion that engage with an inner surface of the first plug to fix the second plug to the first plug.

3. The filter component of claim 2 , further comprising a seal located on the step portion of the second plug to provide a seal between the first plug and the second plug.

4. The filter component of claim 1 , wherein the second plug defines a recess to engage for removing the second plug from the first plug.

5. The filter component of claim 1 , wherein the cartridge portion includes a filter seat that defines a recess that receives the filter media.

6. The filter component of claim 5 , wherein the first plug includes a connector having a plurality of ridged projections that provide a snap fit between the plug assembly and the cartridge portion by engagement with the filter seat.

7. The filter component of claim 5 , further comprising a sealing element positioned on an upper face of the filter seat.

8. The filter component of claim 7 , wherein the sealing element is configured as a face seal having a flat sealing surface.

9. The filter component of claim 5 , wherein the cartridge portion further includes an end cap, and the filter media runs between the filter seat and the end cap.

10. The filter component of claim 9 , wherein the end cap has a top hat configuration for self-aligning the filter component in use, and the top hat configuration includes a protrusion that extends from a cap face.

11. A hydrostatic transmission comprising:

a housing defining a fluid reservoir;

a pump assembly that pumps the fluid through the hydrostatic transmission; and

the filter component of claim 1 , wherein in the installed state the pump assembly pumps the fluid through the filter component to filter the fluid;

and wherein:

in the installed state, the cartridge portion extends through a hole in the housing and the first plug tightly engages the housing to prevent leakage of fluid from the fluid reservoir through the hole;

the housing defines porting in fluid communication with the first flow path defined by the first plug such that in the installed state, fluid flows through the first flow path defined by the first plug and into the porting defined by the housing; and

in the draining state, the first plug is loosened from the housing whereby the housing and the filter component define a draining flow path external from the cartridge portion through which the fluid flows into the drain port.

12. The hydrostatic transmission of claim 11 , wherein the housing comprises a top housing that is fixed to an end block, and a charge pump cover that is fixed to the end block on a side opposite from the top housing, and the first plug engages the charge pump cover of the housing.

13. The hydrostatic transmission of claim 12 , wherein the charge pump cover defines the porting in fluid communication with the first flow path of the first plug.

14. The hydrostatic transmission of claim 11 , wherein an outer diameter of the first plug has a threaded portion and a ridge that engage with an inner surface of the housing to fix the plug assembly to the housing.

15. The hydrostatic transmission of claim 14 , further comprising a seal located on the ridge of the first plug to provide a seal between the first plug and the housing.

16. The hydrostatic transmission of claim 11 , further comprising a charge pump connected in fluid communication between the filter component and the pump assembly.

17. The hydrostatic transmission of claim 11 , wherein:

the cartridge portion of the filter element includes a filter seat that defines a recess that receives the filter media, and a sealing element positioned on an upper face of the filter seat; and

the housing includes a sealing seat against which the sealing element seals in the installed state, and the sealing element is removed from the sealing seat in the draining state.

18. The hydrostatic transmission of claim 17 , wherein the housing comprises a top housing that is fixed to an end block, and the sealing seat is part of end block.

19. The filter component of claim 17 , wherein the sealing element is configured as a face seal having a flat sealing surface that seals against a flat surface of the sealing seat in the installed state.

20. The hydrostatic transmission of claim 11 , wherein the hole through which the cartridge portion extends into the housing has a larger area than the drain port.