Electric drive system
An electric drive system has a group transmission with a main group and a range group with a planetary gear set. First and second input shafts of the main group are respectively coupled with first and second electric engines. An output shaft of the main group is coupled with a first element of the planetary gear set and a second element of the planetary gear set is coupled with an output drive shaft of the group transmission. Two idler wheels are disposed coaxially to the first input shaft and two further idler wheels are disposed coaxially to the second input shaft. The first and second input shafts are coupled with the output shaft via two fixed gears. A first fixed gear engages with the first and third idler wheels and a second fixed gear engages with the second and fourth idler wheels.
1. A purely electric drive system ( 1 ), comprising:
a first electric engine ( 2 );
a second electric engine ( 3 );
a differential transmission ( 16 );
a driven wheel ( 17 ); and
a group transmission ( 7 ) having a main group ( 6 ) and a range group ( 9 ), wherein the range group ( 9 ) has a planetary gear set ( 10 ), wherein a first input shaft ( 4 ) of the main group ( 6 ) is coupled with the first electric engine ( 2 ) such that torques starting from the first electric engine ( 2 ) are introducible into the group transmission ( 7 ) via the first input shaft ( 4 ), wherein a second input shaft ( 5 ) of the main group ( 6 ) is coupled with the second electric engine ( 3 ) such that torques starting from the second electric engine ( 3 ) are introducible into the group transmission ( 7 ) via the second input shaft ( 5 ), wherein an output shaft ( 8 ) of the main group ( 6 ) is permanently coupled with a first element ( 26 ) of the planetary gear set ( 10 ) such that it transfers torque, and wherein a second element ( 12 ) of the planetary gear set ( 10 ) is permanently coupled with an output drive shaft ( 13 ) of the group transmission ( 7 ) such that it transfers torque;
wherein with regard to a torque flow starting from the first electric engine ( 2 ) and the second electric engine ( 3 ) to the driven wheel ( 17 ), the first electric engine ( 2 ), the main group ( 6 ), the range group ( 9 ), a differential gear ( 15 ) and the wheel ( 17 ) are disposed one after the other in this order claimed;
wherein exactly two idler wheels ( 18 , 19 ) comprising a first idler wheel ( 18 ) and a second idler wheel ( 19 ) are disposed coaxially to the first input shaft ( 4 );
wherein exactly two further idler wheels ( 20 , 21 ) comprising a third idler wheel ( 20 ) and a fourth idler wheel ( 21 ) are disposed coaxially to the second input shaft ( 5 );
wherein the first input shaft ( 4 ) and second input shaft ( 5 ) are coupled with the output shaft ( 8 ) via exactly two fixed gears ( 22 , 23 ) disposed coaxially to the output shaft ( 8 ), wherein a first fixed gear ( 22 ) of the two fixed gears ( 22 , 23 ) is in permanent meshed engagement with the first idler wheel ( 18 ) and the third idler wheel ( 20 ), and wherein a second fixed gear ( 23 ) of the two fixed gears ( 22 , 23 ) is in permanent meshed engagement with the second idler wheel ( 19 ) and the fourth idler wheel ( 21 );
wherein a third fixed gear ( 24 ) is disposed coaxially to the output shaft ( 8 ) and permanently meshes with a fourth fixed gear ( 25 ) which is non-rotatably connected to the first element ( 26 ) of the planetary gear set ( 10 );
wherein a gear wheel ( 14 ) non-rotatably connected to the output drive shaft ( 13 ) meshes with the differential gear ( 15 ) which is non-rotatably connected to a differential cage of the differential transmission ( 16 );
wherein an axis of rotation of the first input shaft ( 4 ), an axis of rotation of the second input shaft ( 5 ), an axis of rotation of a sun shaft ( 11 ) of the planetary gear set ( 10 ) and an axis of rotation of the differential gear ( 15 ) are all disposed in parallel and axially offset from one another.
2. The purely electric drive system ( 1 ) according to claim 1 , wherein a first and a second switching element (S 1 , S 1 ′; S 2 , S 2 ′) for the first and second idler wheel ( 18 , 19 ) or the third and fourth idler wheel ( 20 , 21 ) are respectively disposed in a region of each of the first and second input shafts ( 4 , 5 ), wherein the respective first switching element (S 1 , S 1 ′) is equipped to connect the first idler wheel ( 18 ) or the third idler wheel ( 20 ) to its respective input shaft ( 4 , 5 ), and wherein the respective second switching element (S 2 , S 2 ′) is equipped to connect the second idler wheel ( 19 ) or the fourth idler wheel ( 21 ) to its second respective input shaft ( 4 , 5 ).
3. The purely electric drive system ( 1 ) according to claim 2 , wherein the first and second switching element (S 1 , S 1 ′; S 2 , S 2 ′) of the respective first and second input shafts ( 4 , 5 ) are combined into a dual switching element having a neutral position and an actuator.
4. The purely electric drive system according to claim 2 , wherein the fourth fixed gear ( 25 ) is disposed axially overlapping the first switching element (S 1 , S 1 ′) or the second switching element (S 2 , S 2 ′).
5. The purely electric drive system ( 1 ) according to claim 2 , wherein the switching elements (S 1 , S 1 ′; S 2 , S 2 ′) assigned to the respective input shafts ( 4 , 5 ) are respectively configured as claw switching elements.
6. The purely electric drive system ( 1 ) according to claim 1 , further comprising a brake switching element (S 3 ) for stalling a third element ( 28 ) of the planetary gear set ( 10 ).
7. The purely electric drive system ( 1 ) according to claim 6 , further comprising a blocking switching element (S 4 ) for blocking the first and the third elements ( 26 , 28 ) of the planetary gear set ( 10 ).
8. The purely electric drive system ( 1 ) according to claim 7 , wherein the brake switching element (S 3 ) and the blocking switching element (S 4 ) are combined into a dual switching element having an actuator.
9. The purely electric drive system ( 1 ) according to claim 1 , wherein a rotor of the first electric engine ( 2 ) is non-rotatably connected to the first input shaft ( 4 ) and a rotor of the second electric engine ( 3 ) is non-rotatably connected to the second input shaft ( 5 ).
10. The purely electric drive system ( 1 ) according to claim 1 , wherein in the planetary gear set ( 10 ), a sun ( 26 ) is the first element, a planetary carrier ( 12 ) is the second element and a ring gear ( 28 ) is a third element.
11. The purely electric drive system ( 1 ) according to claim 1 , wherein the planetary gear set ( 10 ) is disposed axially overlapping the first electric engine ( 2 ) and axially overlapping the second electric engine ( 3 ).
12. The purely electric drive system ( 1 ) according to claim 1 , wherein the drive shaft ( 13 ) is a hollow shaft and is disposed coaxially to and surrounding the sun shaft ( 11 ).