Hydraulic fluid plenum plate assembly

1. A hydraulic fluid plenum plate assembly in a torque-coupling assembly, said plenum plate assembly rotatably mounted to a rotatable coupling case of said torque-coupling assembly so as to form a plenum chamber between said plenum plate assembly and said coupling case, said coupling case having at least one inlet port fluidly connecting said plenum chamber with a hydraulic pump disposed within said coupling case, said hydraulic fluid plenum plate assembly comprising:

a hydraulic fluid pickup tube for supplying a hydraulic fluid from a hydraulic fluid reservoir to said plenum chamber;

said hydraulic fluid pickup tube having an inlet end and an outlet end;

said inlet end of said pickup tube having an inlet opening submerged in the hydraulic fluid in said hydraulic fluid reservoir;

said outlet end of said pickup tube having an outlet opening fluidly connecting said pickup tube with said plenum chamber, said outlet opening of said pickup tube disposed above said at least one inlet port in said coupling case at any angular position of said coupling case relative to said plenum plate assembly.

2. The plenum plate assembly as defined in claim 1 , further comprising a main plate rotatably mounted to said coupling case so as to form said plenum chamber between said main plate and said coupling case.

3. The plenum plate assembly as defined in claim 2 , further comprising an auxiliary plate secured to said main plate for forming said hydraulic fluid pick-up tube.

4. The plenum plate assembly as defined in claim 3 , wherein one of said main plate and said auxiliary plate is formed with a hydraulic fluid channel facing the other one of said main plate and said auxiliary plate; said hydraulic fluid channel is open at one end and closed at the other end thereof.

5. The plenum plate assembly as defined in claim 4 , wherein said hydraulic fluid channel is curved in a plane parallel to said main plate.

6. The plenum plate assembly as defined in claim 2 , wherein said outlet opening of said pickup tube is formed through said main plate.

7. The plenum plate assembly as defined in claim 2 , further comprising an annular plastic bushing non-rotatably secured to said main plate of said plenum plate assembly; said main plate is rotatably mounted to said coupling case through said plastic bushing.

8. The plenum plate assembly as defined in claim 7 , wherein said main plate includes an annular inner flange defining a central opening therethrough, and wherein said plastic bushing is non-rotatably secured to said inner flange of said main plate.

9. The plenum plate assembly as defined in claim 7 , wherein said plastic bushing is rotatably mounted to a trunnion of said coupling case.

10. The plenum plate assembly as defined in claim 7 , wherein said plastic bushing is provided with at least one annular seal in sealing contact with said coupling case to fluidly seal said plenum chamber.

11. The plenum plate assembly as defined in claim 10 , wherein said at least one annular seal is in sealing contact with a trunnion of said coupling case to fluidly seal said plenum chamber.

12. The plenum plate assembly as defined in claim 2 , wherein said main plate includes an annular outer flange axially extending from said main plate toward said coupling case, said outer flange is provided with at least one annular seal in sealing contact with said coupling case to fluidly seal said plenum chamber.

13. The plenum plate assembly as defined in claim 12 , wherein said at least one annular seal engages an outer peripheral surface of an annular wall extending axially outwardly from said coupling case.

14. The plenum plate assembly as defined in claim 1 , wherein said coupling case is rotatably supported in a coupling housing, said coupling housing is provided for storing a supply of the hydraulic fluid and defines said hydraulic fluid reservoir.

15. The plenum plate assembly as defined in claim 1 , wherein said coupling case has at least one outlet port through which the hydraulic fluid exits said coupling case and into said plenum chamber.

16. A hydraulic fluid plenum plate assembly in a torque-coupling assembly, said plenum plate assembly rotatably mounted to a rotatable coupling case of said torque-coupling assembly so as to form a plenum chamber between said plenum plate assembly and said coupling case, said hydraulic fluid plenum plate assembly comprising:

a hydraulic fluid pickup tube for supplying a hydraulic fluid from a hydraulic fluid reservoir to said plenum chamber;

said hydraulic fluid pickup tube having an inlet end and an outlet end;

said inlet end of said pickup tube having an inlet opening submerged in the hydraulic fluid in said hydraulic fluid reservoir;

said outlet end having an outlet opening for fluidly connecting said pickup tube with said plenum chamber, said outlet opening being disposed substantially higher than a level of the hydraulic fluid in said hydraulic fluid reservoir when said torque-coupling assembly is stationary;

said plenum chamber being partially immersed in the hydraulic fluid in said hydraulic fluid reservoir.

17. The plenum plate assembly as defined in claim 16 , further comprising a main plate rotatably mounted to said coupling case so as to form said plenum chamber between said main plate and said coupling case; said outlet opening is formed through said main plate.

18. The plenum plate assembly as defined in claim 17 , further comprising an auxiliary plate secured to said main plate for forming said hydraulic fluid pick-up tube.

19. The plenum plate assembly as defined in claim 18 , wherein one of said main plate and said auxiliary plate is formed with a hydraulic fluid channel facing the other one of said main plate and said auxiliary plate; said hydraulic fluid channel is open at one end and closed at the other end thereof.

20. The plenum plate assembly as defined in claim 17 , further comprising an annular plastic bushing non-rotatably secured to said main plate of said plenum plate assembly; said main plate is rotatably mounted to said coupling case through said plastic bushing.