Shift element sub-assembly for a transmission

1. A shift element subassembly for a transmission with two axially adjacent shift elements ( 2 , 3 ) which can be actuated hydraulically or pneumatically, and arranged in a transmission housing ( 1 ) with a common disc carrier ( 4 ) for accommodating external discs ( 20 , 21 ) or internal discs of both shift elements ( 2 , 3 ), whereby the discs of both shift elements ( 2 , 3 ) a rearranged axially adjacent inside the disc carrier ( 4 ) and are separated from each other by a central partition ( 40 ) of the disc carrier ( 4 ), whereby each shift element ( 2 , 3 ) has a piston( 23 , 33 ) and a closing pressure chamber ( 24 , 34 ) for actuation, which are arranged on the side of the disk of the respective shift element ( 2 , 3 ) facing away from the partition ( 40 ) in the region of the front faces ( 41 , 43 ) of the disc carrier ( 4 ), wherein each shift element ( 2 , 3 ) has at least one resetting element ( 27 , 37 , 39 ) for piston resetting which is arranged in the disc carrier ( 4 ) radially above the discs of the respective shift element ( 2 , 3 ), wherein each shift element ( 2 , 3 ) has an additional secondary piston ( 26 , 36 ) that acts through the piston ( 23 , 33 ) of the respective shift element ( 2 , 3 ) against a resetting force of the resetting element ( 27 , 37 , 39 ) of the respective shift element ( 2 , 3 ) on the discs of the respective shift element ( 2 , 3 ), and wherein the resetting elements ( 27 , 37 , 39 ) operate independently of one another and at least one resetting element ( 27 , 37 , 39 ) of the shift element subassembly is constructed as a drain pressure chamber ( 27 , 37 ).

2. The shift element subassembly according to claim 1 , wherein recesses ( 42 , 44 ) are provided in a region of the front faces ( 41 , 43 ) of the disc carrier ( 4 ) in a peripheral direction in which the resetting elements ( 27 , 37 , 39 ) allocated to the shift elements ( 2 , 3 ) are arranged and into which the secondary pistons ( 26 , 36 ) allocated to the shift elements ( 2 , 3 ) open axially displaceably.

3. The shift element subassembly according to claim 2 , wherein an adjusting ring ( 21 , 31 ) allocated to the respective shift element ( 2 , 3 ) is provided in the region of the front faces ( 41 , 43 ) of the disc carrier ( 4 ) on which the secondary piston ( 26 , 36 ) of the respective shift element ( 2 , 3 ) when the shift element ( 2 , 3 ) is open, whereby the discs of this shift element ( 2 , 3 ) moreover have a specified air play ( 22 , 32 ).

4. The shift element subassembly according to claim 2 , wherein the disc carrier ( 4 ) can be pre-assembled with the discs of both shift elements ( 2 , 3 ), the secondary pistons ( 26 , 36 ) and the adjusting rings ( 21 , 31 ) as a subassembly element, whereby the air plays of the respective discs can be adjusted over variously wide adjustment rings ( 21 , 31 ).

5. The shift element subassembly according to claim 2 , wherein the shift elements ( 2 , 3 ) are constructed as brakes, whereby their common disc carrier ( 4 ) is constructed as an external disc carrier and is connected by one of form-locking or force-locking with the transmission housing ( 1 ).

6. A method for controlling the shift element subassembly for a transmission with two axially adjacent shift elements ( 2 , 3 ) which can be actuated hydraulically or pneumatically and arranged in a transmission housing ( 1 ) with a common disc carrier ( 4 ) for accommodating external discs ( 20 , 21 ) or internal discs of both shift elements ( 2 , 3 ), whereby the discs of both shift elements ( 2 , 3 ) are arranged axially adjacent inside the disc carrier ( 4 ) and are separated from each other by a central partition ( 40 ) of the disc carrier ( 4 ), whereby each shift elements ( 2 , 3 ) has a piston ( 23 , 33 ) and a closing pressure chamber ( 24 , 34 ) for actuation which are arranged on the side of the disk of the respective shift element ( 2 , 3 ) facing away from the partition ( 40 ) in the region of the front faces ( 41 , 43 ) of the disc carrier ( 4 ), the method comprising the steps of:

independently resetting each shift element ( 2 , 3 ) by positioning at least one resetting element ( 27 , 37 , 39 ) for piston resetting arranged in the disc carrier ( 4 ) radially above the discs of the respective shift element ( 2 , 3 ),

providing each shift element ( 2 , 3 ) with an additional secondary piston ( 26 , 36 ) that acts through the piston ( 23 , 33 ) of the respective shift element ( 2 , 3 ) against a resetting force of the resetting element ( 27 , 37 , 39 ) of the respective shift element ( 2 , 3 ) on the discs of the respective shift element ( 2 , 3 ), and

constructing at least one resetting element ( 27 , 37 , 39 ) of the shift element subassembly as a drain pressure chamber ( 27 , 37 ), and

actuating the drain pressure chamber ( 27 , 37 ) with modulatable pressure according to at least one of a specific shift and temperature.

7. The method for controlling the shift element subassembly according claim 6 , further comprising the step of:

controlling the pressure reduction in the closing pressure chamber ( 24 , 34 ) when opening the shift elements ( 2 , 3 ) according to one of a specific shift and depending upon temperature.

8. The method for controlling the shift element subassembly according claim 6 , further comprising the step of:

controlling the closing pressure chamber ( 24 , 34 ) and drain pressure chamber ( 27 , 37 ) by pressure-modulation, as a differential pressure chamber upon at least one of closing and opening the respective shift element ( 2 , 3 ) as a of a specific shift.

9. A shift element subassembly for a transmission comprising:

a first and a second axially adjacent shift elements ( 2 , 3 ) which can be actuated hydraulically or pneumatically, and arranged in a transmission housing ( 1 ) with a common disc carrier ( 4 ) for accommodating external discs ( 20 , 21 ) or internal discs of both shift elements ( 2 , 3 ), the discs of both shift elements ( 2 , 3 ) are arranged axially adjacent inside the disc carrier ( 4 ) and are separated from each other by a central partition ( 40 ) of the disc carrier ( 4 ), said first and second shift elements ( 2 , 3 ) further comprising:

a first and a second piston ( 23 , 33 ) and a closing pressure chamber ( 24 , 34 ) for actuation of the respective shift element ( 2 , 3 ), which are arranged on the side of the disk of the respective shift element ( 2 , 3 ) facing away from the partition ( 40 ) in the region of the front faces ( 41 , 43 ) of the disc carrier ( 4 );

a first resetting element ( 27 ) arranged in the disc carrier ( 4 ) radially above the discs of the first shift element ( 2 , 3 ) for resetting the respective piston of the first shift element ( 2 );

a second resetting element ( 37 ) arranged in the disc carrier ( 4 ) radially above the discs of the second shift element ( 2 , 3 ) for resetting the respective piston of the second shift element ( 3 );

a first secondary piston ( 26 , 36 ) that acts through the first piston ( 23 ) of the first shift element ( 2 , 3 ) against a resetting force of the first resetting element ( 27 ) on the discs of the first shift element ( 2 ),

a second secondary piston ( 36 ) that acts through the second piston ( 33 ) of the second shift element ( 3 ) against a resetting force of the second resetting element ( 27 ) on the discs of the second shift element ( 3 ), and

wherein the first and second resetting elements ( 27 , 37 , 39 ) operate independently of one another on their respective first and second shift elements ( 2 , 3 ) and at least one of the first and second resetting elements ( 27 , 37 ) is constructed as a drain pressure chamber ( 27 , 37 ).