DUAL CLUTCH GEARBOX FOR AN ELECTRIC VEHICLE AND DRIVE UNIT FOR AN ELECTRIC VEHICLE

Description

[0001] The invention relates to a dual-clutch transmission for an electric vehicle, comprising an input shaft, a first partial clutch by means of which the input shaft can be coupled to a first output shaft, and a second partial clutch by means of which the input shaft can be coupled to a second output shaft. The invention also relates to a drive unit for an electric vehicle, comprising a dual-clutch transmission according to the invention. State of the art

[0002] Dual-clutch transmissions for motor vehicles comprise two sub-transmissions, enabling fully automatic gear changes without interruption of traction. Each sub-transmission has its own clutch, which connects an output shaft of the respective sub-transmission to an input shaft. The output shafts of the sub-transmissions are connected to a common output shaft via further gear stages. This allows for various speed ratios between the input and output shafts.

[0003] Document DE 102017203542 A1 discloses a transmission for a motor vehicle. The transmission has a first clutch and a second clutch, which can be coupled independently of each other to a clutch carrier. The first clutch comprises a first actuating unit with a first release bearing. The second clutch comprises a second actuating unit with a second release bearing.

[0004] Document DE 102016124812 A1 discloses a friction clutch device for a motor vehicle, which is designed as a dual clutch. The dual clutch comprises an actuating device which engages a first

[0005] It has a release bearing and a second release bearing. The first release bearing is assigned to a first partial clutch, and the second release bearing is assigned to a second partial clutch.

[0006] Document DE 102017102733 A1 discloses a dual clutch for a motor vehicle, comprising a first partial clutch and a second partial clutch. A lever element is provided for actuating the clutch. A pivoting movement of the lever element axially displaces a pressure plate via a tie rod.

[0007] Document DE 102011102329 A1 discloses a dual clutch for a motor vehicle, comprising two friction clutches. One of the two friction clutches is associated with a lever spring. The lever spring acts on a tie rod, which then axially displaces a pressure plate.

[0008] Document DE 102016216322 A1 discloses a coupling device with two lamellar carriers. The coupling device has an input shaft, a first partial coupling by means of which the input shaft can be coupled to a first output shaft, and a second partial coupling by means of which the input shaft can be coupled to a second output shaft, wherein the second output shaft is designed as a hollow shaft, has a flange section extending in the radial direction, and a driver connected to the second output shaft extends through the flange section.

[0009] Another example of a double clutch according to the preamble of claim 1 can be found in CN 105 465 215 B. Disclosure of the invention

[0010] A dual-clutch transmission for an electric vehicle is proposed. The dual-clutch transmission according to the invention is disclosed in claim 1 and comprises an input shaft driven by an electric motor, a first output shaft, and a second output shaft. The dual-clutch transmission further comprises a first partial clutch by means of which the input shaft can be coupled to the first output shaft, and a second partial clutch by means of which the input shaft can be coupled to the second output shaft.

[0011] The second output shaft is designed as a hollow shaft. According to the invention, the second output shaft surrounds the first output shaft coaxially. The first and second output shafts rotate about a common axis. A direction parallel to the axis of rotation is referred to below as the axial direction. A direction perpendicular to the axis of rotation is referred to below as the radial direction.

[0012] The second output shaft has a flange section extending radially. The second partial coupling is located in a radially outer region of this flange section. When an axial contact force, for example via a pressure plate, acts on the second partial coupling and simultaneously opens the first partial coupling, the second partial coupling closes and the input shaft is coupled to the second output shaft.

[0013] The first partial coupling can be actuated by a first actuating unit, which has a drive element. The drive element of the first actuating unit extends axially through the flange section of the second output shaft. The drive element of the first actuating unit is rotationally fixed to the second output shaft.

[0014] According to the invention, the first actuating unit comprises a first release bearing and a second release bearing. The driver of the first actuating unit can be actuated axially via the first release bearing, and the first partial clutch can be actuated axially by the driver, for example via a pressure plate, via the second release bearing.

[0015] When an axial clamping force acts on the first release bearing, this force is transmitted from the first release bearing via the drive pin to the second release bearing. The second release bearing transmits the clamping force, for example via a pressure plate, to the first partial clutch, which then engages. This engages the input shaft with the first output shaft. The clamping force is transmitted axially through the flange section of the second output shaft.

[0016] Preferably, the driver of the first actuating unit is axially displaceable relative to the flange section of the second output shaft. Thus, when a clamping force acts axially on the first release bearing, the clamping force is transmitted from the first release bearing via the driver, which then moves axially and transmits the clamping force to the second release bearing.

[0017] According to a preferred embodiment of the invention, the partial clutches of the dual-clutch transmission are arranged such that the second partial clutch coaxially surrounds the first partial clutch. This advantageously reduces the installation space required for the partial clutches.

[0018] According to an advantageous embodiment of the invention, the first partial coupling is designed as a multi-plate coupling, and / or the second partial coupling is designed as a multi-plate coupling. The partial couplings preferably have multi-plate packs which can be actuated by a clamping force acting in the axial direction.

[0019] Preferably, the first actuating unit has a first pressure plate for actuating the first partial clutch. The first pressure plate can be actuated by the second release bearing. The second actuating unit preferably has a second pressure plate for actuating the second partial clutch.

[0020] According to an advantageous embodiment of the invention, the first pressure plate of the first actuating unit is rotationally fixed to the first output shaft. Preferably, the first pressure plate is axially displaceable relative to the first output shaft.

[0021] According to another advantageous embodiment of the invention, the first pressure plate of the first actuating unit is rotatably mounted relative to the first output shaft. Preferably, the first pressure plate is axially displaceable relative to the first output shaft.

[0022] Preferably, the first output shaft is non-rotatably connected to a first pinion. The first pinion meshes with a first gear. Preferably, the second output shaft is also non-rotatably connected to a second pinion. The second pinion meshes with a second gear. The first pinion and the first gear form a first gear stage. The second pinion and the second gear form a second gear stage.

[0023] Preferably, the first and second gears are connected to a common output shaft in a rotationally fixed manner. The output shaft can also be connected to a third pinion in a rotationally fixed manner. This third pinion meshes, for example, with a third gear, which serves to drive a differential.

[0024] A drive unit for an electric vehicle is also proposed. This drive unit comprises a dual-clutch transmission according to the invention and an electric motor for driving the input shaft of the dual-clutch transmission according to the invention. Advantageously, the drive unit according to the invention also includes a differential gear by means of which two drive wheels of the electric vehicle can be driven. Advantages of the invention

[0025] A dual-clutch transmission according to the invention is designed to be very space-saving, particularly due to the coaxial arrangement of the two sub-transmissions. The first sub-clutch, which is preferably located radially inside and coaxially surrounded by the second sub-clutch, can be actuated through the radially extending flange section of the second output shaft. The design of the first actuating unit allows the first sub-clutch to be actuated through this flange section of the second output shaft, even though the second output shaft operates at a different speed than the first. Accessibility to a clutch pack of the first sub-clutch is thus advantageously improved. The first actuating unit can be arranged on the side of the two sub-clutches facing away from the input shaft.This allows for flexible adaptation of the dual-clutch transmission to the installation space available in an electric vehicle. Furthermore, a dual-clutch transmission according to the invention is relatively inexpensive to manufacture. A dual-clutch transmission according to the invention can also include other partial clutches, such as disc clutches, instead of multi-plate clutches. A drive unit according to the invention for an electric vehicle is also relatively space-saving and inexpensive to manufacture. Brief description of the drawings

[0026] Embodiments of the invention are explained in more detail with reference to the drawings and the following description.

[0027] They show: Figure 1 is a schematic representation of a drive unit for an electric vehicle, Figure 2 is a sectional view of a dual-clutch transmission of the drive unit. Figure 1and Figure 3 a sectional view of a first actuating unit of the dual clutch transmission made of Figure 2 . Embodiments of the invention

[0028] In the following description of embodiments of the invention, identical or similar elements are designated by the same reference numerals, and repeated descriptions of these elements are omitted in individual cases. The figures represent the subject matter of the invention only schematically.

[0029] Figure 1Figure 1 shows a schematic representation of a drive unit 100 for an electric vehicle. The drive unit 100 comprises a dual-clutch transmission 10 and an electric motor 5. The electric motor 5 drives an input shaft 40 of the dual-clutch transmission 10. The drive unit 100 according to the invention further comprises a differential gear 90. The differential gear 90 drives a first drive wheel 91 and a second drive wheel 92 of the electric vehicle via separate axle drives.

[0030] The dual-clutch transmission 10, as already mentioned, comprises the input shaft 40, which is driven by the electric motor 5. Furthermore, the dual-clutch transmission 10 comprises a first output shaft 41 and a second output shaft 42. The dual-clutch transmission 10 also comprises a first partial clutch 11 and a second partial clutch 12. The first partial clutch 11 allows the input shaft 40 to be coupled to the first output shaft 41. The second partial clutch 12 allows the input shaft 40 to be coupled to the second output shaft 42.

[0031] The dual-clutch transmission 10 also includes a first pinion 21 and a second pinion 22. The first output shaft 41 is non-rotatably connected to the first pinion 21. The second output shaft 42 is non-rotatably connected to the second pinion 22. The dual-clutch transmission 10 further includes a first gear 31, a second gear 32, and an output shaft 45. The first gear 31 and the second gear 32 are non-rotatably connected to the common output shaft 45.

[0032] The first pinion 21 meshes with the first gear 31. The first pinion 21 and the first gear 31 form a first gear stage. The second pinion 22 meshes with the second gear 32. The second pinion 22 and the second gear 32 form a second gear stage. The first gear stage and the second gear stage have different gear ratios. The dual-clutch transmission 10 thus allows two different gear ratios between the speed of the input shaft 40 and the speed of the output shaft 45.

[0033] The output shaft 45 of the dual-clutch transmission 10 is also rotationally fixed to a third pinion 23. The third pinion 23 meshes with a third gear 33. The third gear 33 drives the differential 90 of the drive unit 100. The differential 90 can thus be driven by the electric motor 5 via the dual-clutch transmission 10 with two different gear ratios.

[0034] Figure 2 shows a sectional view of part of the dual-clutch transmission 10 of the in Figure 1 The drive unit 100 is shown. The two pinions 21, 22, the two gears 31, 32, and the output shaft 45 are not shown. The second output shaft 42 is designed as a hollow shaft. The second output shaft 42 coaxially surrounds the first output shaft 41, which is designed as a solid shaft.

[0035] The first output shaft 41 and the second output shaft 42 thus rotate about the same axis of rotation A. The input shaft 40 also rotates about the axis of rotation A. A direction parallel to the axis of rotation A is referred to below as the axial direction x. A direction perpendicular to the axis of rotation A is referred to below as the radial direction r.

[0036] The first partial coupling 11 and the second partial coupling 12 are each designed as multi-plate couplings. The first partial coupling 11 and the second partial coupling 12 each have a plate pack which can be actuated by a contact force acting in the axial direction x. The second partial coupling 12 surrounds the first partial coupling 11 coaxially.

[0037] The first partial clutch 11 has a first plate carrier 71 on which plates of the associated plate pack are arranged. Corresponding plates of the associated plate pack are arranged on a corresponding carrier of the input shaft 40. The dual-clutch transmission 10 comprises a first actuating unit 51 for actuating the first partial clutch 11.

[0038] The second partial clutch 12 has a second plate carrier 72, on which plates of the associated plate pack are arranged. Corresponding plates of the associated plate pack are arranged on a corresponding carrier of the input shaft 40. The dual-clutch transmission 10 includes a second actuating unit 52 for actuating the second partial clutch 12.

[0039] The dual-clutch transmission 10 further comprises a first shift unit 55 for driving the first actuating unit 51. The first shift unit 55 includes a geared motor. The dual-clutch transmission 10 also comprises a second shift unit 56 for driving the second actuating unit 52. The second shift unit 56 also includes a geared motor.

[0040] The second output shaft 42 has a flange section 65 extending in the radial direction r. The second lamellar carrier 72 is attached to the lamellar pack in a radially outer region of the flange section 65. Thus, the second partial coupling 12 is also located in a radially outer region of the flange section 65.

[0041] The first actuating unit 51 has a first pressure plate 53 for actuating the first partial clutch 11. When a contact force in the axial direction x acts on the first pressure plate 53, the first pressure plate 53 compresses the lamellar pack of the first partial clutch 11 and the first partial clutch 11 closes. This couples the input shaft 40 with the first output shaft 41.

[0042] The second actuating unit 52 has a second pressure plate 54 for actuating the second partial clutch 12. When a contact force in the axial direction x acts on the second pressure plate 54, the second pressure plate 54 compresses the lamellar pack of the second partial clutch 12 and the second partial clutch 12 closes. This couples the input shaft 40 with the second output shaft 42.

[0043] Figure 3 shows a sectional view of the first actuating unit 51 for actuating the first partial clutch 11 of the dual clutch transmission 10. Figure 2 . The first actuating unit 51 is, as already mentioned, driven by a first switching unit 55, which is not shown here.

[0044] The first actuating unit 51 has a driver 64. The driver 64 of the first actuating unit 51 extends axially x through the flange section 65 of the second output shaft 42 (not shown). The driver 64 of the first actuating unit 51 is rotationally fixed to the second output shaft 42. However, the driver 64 of the first actuating unit 51 is displaceable axially x relative to the flange section 65 of the second output shaft 42.

[0045] The first actuating unit 51 further comprises a first release bearing 61 and a second release bearing 62. The driver 64 is arranged in the axial direction x between the first release bearing 61 and the second release bearing 62. The second release bearing 62 is arranged in the axial direction x between the driver 64 and the first pressure plate 53.

[0046] The first actuating unit 51 further comprises a pressure ring 67 and a spreading disc 68. The first release bearing 61 is arranged in the axial direction x between the driver 64 and the pressure ring 67. The spreading disc 68 is arranged in the axial direction x on a side of the pressure ring 67 facing away from the first release bearing 61.

[0047] The first release bearing 61 is designed as a ball bearing. The first release bearing 61 allows a contact force in the axial direction x to be transmitted from the pressure ring 67 to the driver 64. At the same time, the first release bearing 61 allows the driver 64 to rotate relative to the pressure ring 67.

[0048] The second release bearing 62 is designed as a ball bearing. The second release bearing 62 allows a contact force in the axial direction x to be transmitted from the driver 64 to the first pressure plate 53. Simultaneously, the second release bearing 62 allows the first pressure plate 53 to rotate relative to the driver 64.

[0049] To engage the first partial clutch 11 of the dual-clutch transmission 10, the first shift unit 55 is activated. The first shift unit 55 then applies a clamping force in the axial direction x to the spreading disc 68 of the first actuating unit 51. This causes the spreading disc 68 to be displaced in the axial direction x, transmitting the clamping force to the pressure ring 67. This, in turn, causes the pressure ring 67 to be displaced in the axial direction x, transmitting the clamping force to the first release bearing 61.

[0050] The first release bearing 61 is thereby displaced in the axial direction x and transmits the clamping force to the driver 64. The driver 64 is thereby displaced in the axial direction x relative to the flange section 65 of the second output shaft 42 and transmits the clamping force to the second release bearing 62. The driver 64 rotates at the speed of the second output shaft 42. The clamping force is thus transmitted in the axial direction x through the flange section 65 of the second output shaft 42.

[0051] The second release bearing 62 is thereby displaced in the axial direction x and transmits the clamping force to the first pressure plate 53. The first pressure plate 53 is thereby displaced in the axial direction x and transmits the clamping force to the multi-plate assembly of the first partial clutch 11. The first partial clutch 11 then engages. This couples the input shaft 40 with the first output shaft 41. The first pressure plate 53 then rotates at the speed of the first output shaft 41.

[0052] The invention is not limited to the embodiments described here and the aspects highlighted therein. Rather, within the scope specified by the claims, a multitude of modifications are possible that fall within the bounds of what is considered skilled in the art.

Claims

1. Dual-clutch transmission (10) for an electric vehicle, comprising an input shaft (40), a first component clutch (11) by means of which the input shaft (40) is able to be coupled to a first drive-output shaft (41), and a second component clutch (12) by means of which the input shaft (40) is able to be coupled to a second drive-output shaft (42), wherein the second drive-output shaft (42) is in the form of a hollow shaft, wherein the second drive-output shaft (42) has a flange portion (65) which extends in a radial direction (r), wherein the first component clutch (11) is able to be actuated by a first actuating unit (51) having a driver (64), which driver engages through the flange portion (65) in an axial direction (x) and is connected rotationally conjointly to the second drive-output shaft (42), and the first component clutch (11) is able to be activated by the driver (64) in the axial direction (x) via a release bearing (62), wherein the second component clutch (12) coaxially surrounds the first component clutch (11), wherein the first component clutch (11) is in the form of a multi-plate clutch and the second component clutch (12) is in the form of a multi-plate clutch, wherein the first component clutch (11) has a first plate carrier (71) on which plates of an associated set of plates are arranged and which is connected to the first drive-output shaft (41), and wherein a corresponding carrier of the input shaft (40) has corresponding plates of the associated set of plates arranged on it, characterized in that the driver (64) is able to be activated in the axial direction (x) via a first release bearing (61) and the first component clutch (11) is able to be activated by the driver (64) in the axial direction (x) via a second release bearing (62), and in that the plates arranged on the first plate carrier (71) are oriented radially outwards and the plates arranged on the corresponding carrier of the input shaft (40) corresponding thereto are oriented radially inwards, and the connection between the first drive-output shaft (41) and the first plate carrier (71) is not engaged through by the driver (64).

2. Dual-clutch transmission (10) according to Claim 1, characterized in that the driver (64) is displaceable in the axial direction (x) relative to the flange portion (65).

3. Dual-clutch transmission (10) according to one of the preceding claims, characterized in that the first actuating unit (51) has a first pressure plate (53) for actuating the first component clutch (11), which is able to be activated by the second release bearing (62).

4. Dual-clutch transmission (10) according to Claim 3, characterized in that the first pressure plate (53) is connected rotationally conjointly to the first drive-output shaft (41).

5. Dual-clutch transmission (10) according to Claim 3, characterized in that the first pressure plate (53) is mounted so as to be rotatable relative to the first drive-output shaft (41).

6. Dual-clutch transmission (10) according to one of the preceding claims, characterized in that the first drive-output shaft (41) is connected rotationally conjointly to a first pinion (21) which meshes with a first gearwheel (31), and in that the second drive-output shaft (42) is connected rotationally conjointly to a second pinion (22) which meshes with a second gearwheel (32).

7. Dual-clutch transmission (10) according to Claim 6, characterized in that the first gearwheel (31) and the second gearwheel (32) are connected rotationally conjointly to an output shaft (45) which is able to be connected rotationally conjointly to a third pinion (23).

8. Drive unit (100) for an electric vehicle, comprising a dual-clutch transmission (10) according to one of the preceding claims and an electric motor (5) for driving the input shaft (40) of the dual-clutch transmission (10).