Transmission and transmission clutch system

Patent metadata

Field	Value
Publication number	US-10161426-B2
Application number	US-201615080910-A
Country	US
Kind code	B2
Filing date	Mar 25, 2016
Priority date	Mar 25, 2016
Publication date	Dec 25, 2018
Grant date	Dec 25, 2018

Abstract

A transmission includes a case, a clutch pack, a piston. The case defines a bore that transitions along a step from a first to a second diameter. The piston is disposed within the bore. The piston has first and second seals that engage the case along the first and second diameters, respectively. The piston defines a chamber that is encompassed by the piston, the case, the first seal, and the second seal. The piston is configured to engage a clutch pack when hydraulic fluid is channeled into the chamber.

First claim

What is claimed is:

1. A transmission comprising:
a case defining a bore that transitions along a step from a first to a second diameter; and
a piston disposed within the bore, having first and second seals engaging the case along the first and second diameters, respectively, and defining a chamber encompassed by the piston, case, first seal, and second seal, wherein the piston is configured to engage a clutch pack when hydraulic fluid is channeled into the chamber, and wherein the piston includes a degassing valve that is configured to exhaust gas from the chamber to an interior of the piston.

2. The transmission of claim 1 , wherein the piston defines a channel that fluidly communicates the chamber to the interior of the piston, and wherein the degassing valve is disposed within the channel.

3. The transmission of claim 1 , wherein the degassing valve is located circumferentially on the piston adjacent to a top center location of the case.

4. The transmission of claim 3 , wherein the piston includes an anti-rotation device that is configured to prevent rotation of the piston such that the degassing valve remains adjacent to the top center location.

5. The transmission of claim 4 , wherein the anti-rotation device is a protrusion that extends from the piston and engages a slot defined by the case.

6. A clutch engagement piston comprising:
a piston body having an exterior surface defining first and second diameters, and a step between the diameters;
first and second seals extending from the exterior surface at the first and second diameters, respectively; and
a degassing valve disposed adjacent to the step and configured to exhaust gas located in an exterior space defined by the exterior surface to an interior space defined by an interior surface of the body.

7. The piston of claim 6 , wherein the piston body defines a channel that fluidly communicates the exterior space with the interior space, and wherein the degassing valve is disposed within the channel.

8. The piston of claim 6 , further comprising an anti-rotation device configured to engage a transmission case to prevent rotation of the piston such that the degassing valve remains adjacent to a top center location of the case.

9. The piston of claim 8 , wherein the anti-rotation device is a protrusion that extends from the piston body and is configured to engage a slot defined by the transmission case.

10. The piston of claim 6 , wherein a chamber is defined adjacent to the step and between the piston body and a transmission case when the piston is disposed within a bore defined by the transmission case, and wherein the piston is configured to engage a clutch pack when hydraulic fluid is channeled into the chamber.

11. The piston of claim 10 , wherein the chamber is encompassed by the piston body, transmission case, first seal, and second seal.

12. The piston of claim 11 , wherein the degassing valve is configured to exhaust gas from the chamber to the interior space when the piston is disposed within the bore of the transmission case.

13. A clutch comprising:
a clutch pack; and
a piston configured to engage the clutch pack to activate the clutch and having,
an outer surface defining a first diameter, a second diameter, and a step between the first and second diameters,
first and second seals extending from the outer surface at the first and second diameters, respectively, each seal configured to engage a transmission case, and
an anti-rotation device extending from the outer surface and configured to engage the transmission case to prevent piston rotation such that a degassing valve is maintained at a top center location of the transmission case.

14. The piston of claim 13 , wherein the degassing valve is disposed adjacent to the step and configured to exhaust gas from an exterior space relative to the piston to an interior space relative to the piston.

15. The piston of claim 14 , wherein the piston defines a channel that fluidly communicates the exterior space with the interior space, and wherein the degassing valve is disposed within the channel.

16. The piston of claim 13 , wherein the anti-rotation device is a protrusion that extends from the piston and is configured to engage a slot defined by the transmission case.

17. The piston of claim 13 , wherein a chamber is defined adjacent to the step and between the piston and the transmission case when the piston is disposed within a bore defined by the transmission case, and wherein the piston is configured to engage the clutch pack when hydraulic fluid is channeled into the chamber.

18. The piston of claim 17 , wherein the chamber is encompassed by the piston, transmission case, first seal, and second seal.

19. The piston of claim 18 , wherein the degassing valve is configured to exhaust gas from the chamber to an interior space relative to the piston when the piston is disposed within the bore of the transmission case.

Assignees

• Ford Global Tech Llc

Inventors

• Heuver Bradley Ronald

Classifications

• F16D2300/08

  Details or arrangements of sealings not provided for in group F16D3/84 · CPC title

• F16D25/0635

  with flat friction surfaces, e.g. discs · CPC title

• F16H2057/02047

  Automatic transmissions · CPC title

• F15B15/1414

  with non-rotatable piston · CPC title

• F16D25/12

  Details not specific to one of the before-mentioned types · CPC title