Motor vehicle transaxle having a differential mechanism controlled by an on-demand clutch

1. A transaxle for transmitting power to the drive wheels of a vehicle, comprising:

a transaxle case;

a differential mechanism located in the case, including an input and transmitting power between the input and at least two halfshafts;

a clutch located in the case, including a cylinder and a piston in the cylinder, for controlling a differential between a speed of the input and a speed of one of the halfshafts; and

a hydraulic system located in the case, including a passage parallel to a halfshaft and a surface of the case, hydraulically communicating an inlet and the cylinder, the inlet being sealed against passage of fluid by seal rings located in a wall that surrounds the passage.

2. The transaxle of claim 1 , wherein the passage is bounded by a wall located adjacent a surface of a halfshaft and a radially outer wall located adjacent a surface of the transaxle case.

3. The transaxle of claim 1 , wherein the passage is bounded by a radially inner wall located adjacent an outer surface of a halfshaft and a radially outer wall located adjacent a surface of the transaxle case, the seal rings being located in the outer wall and contacting a nonrotating surface, a first seal ring located at a first side of the inlet, a second seal ring located at a second side of the inlet axially opposite the first side.

4. The transaxle of claim 1 , further comprising:

a first member driveably connected to the output and including a radially outer wall of the passage rotatably supported on the transaxle case and forming a portion of the cylinder;

a second member secured to the first member for rotation therewith, spaced radially from the first connecting member, and including a radially inner wall of the passage located adjacent an outer surface of a halfshaft.

5. The transaxle of claim 1 , further comprising:

a first member driveably connected to the output and including a radially outer wall of the passage, the seal rings includes first and second seal rings being located in the outer wall and contacting a non rotating surface, the first seal ring located at a first side of the inlet, the second seal ring located at a second side of the inlet axially opposite the first side; and

a second member spaced radially from the first connecting member and including a radially inner wall of the passage located adjacent an outer surface of a halfshaft.

6. The transaxle of claim 1 , further comprising:

a first member forming a portion of the cylinder, driveably connected to the output and including a radially outer wall of the passage, the seal rings includes first and second seal rings being located in the outer wall and contacting a nonrotating surface, the first sealing ring located at a first side of the inlet, the second sealing ring located at a second side of the inlet axially opposite the first side; and

a second member spaced radially from the first connecting member and including a radially inner wall of the passage located adjacent an outer surface of a halfshaft.

7. The transaxle of claim 1 , wherein the clutch further comprises:

friction discs;

spacer plates, a spacer plate located between successive friction discs, the discs and plates arranged in a stack;

a blocker plate located at an end of the stack for securing the stack against movement;

a pressure plate located at an opposite end of the stack from the blocker plate; and

a Belleville spring supported for pivoting movement, contacting the pressure plate and actuated by the piston, the spring acting as a lever and applying a greater force to the pressure plate than a force applied to the spring by the piston.

8. The transaxle of claim 1 , wherein the clutch further comprises:

spacer plates, a spacer plate located between successive friction discs, the discs and plates arranged in a stack;

a blocker plate located at an end of the stack for securing the stack against movement;

a pressure plate located at an opposite end of the stack from the blocker plate; and

a return spring contacting the piston for urging the piston away from contact with the pressure plate.

9. A transaxle for transmitting power to the drive wheels of a vehicle, comprising:

a transaxle case;

a differential including a bevel pinion driveably connected to an input, a bevel gear engaged with a first halfshaft, and a second bevel gear driveably connected to a second halfshaft, each gear engaged with the pinion;

a clutch located in the case including a cylinder and a piston in the cylinder, for controlling a differential between a speed of the input and a speed of the first halfshaft; and

a hydraulic system located in the case, including a passage parallel to a halfshaft and a surface of the case, hydraulically communication an inlet and the cylinder, the inlet being sealed against passage of fluid by seal rings located in a wall that surrounds the passage;

a first member driveably connected to the input, supported on the case, forming a portion of the cylinder, and

a second member secured to the first member, including a wall of the passage and located adjacent the first halfshaft.

10. The transaxle of claim 9 , wherein:

the seal rings include first and second seal rings are located in a wall and contacting a nonrotating surface, the first seal ring is located at a first side of the inlet, the second seal ring is located at a second side of the inlet axially opposite the first side; and

the second member includes a radially inner wall of the passage located adjacent an outer surface of a halfshaft.

11. The transaxle of claim 9 , wherein the clutch further comprises:

spacer plates, a spacer plate located between successive friction discs, the discs and plates arranged in a stack;

a blocker plate located at an end of the stack for securing the stack against movement;

a pressure plate located at an opposite end of the stack from the blocker plate; and

a return spring contacting the piston for urging the piston away from contact with the pressure plate.