A dual clutch and a drive system equipped with the same

Abstract

This invention relates to a dual-clutch (10) and a drive system having a first clutch (12a) and a second clutch (12b), wherein the first clutch (12a) and the second clutch (12b) are each actuated by means of hydraulic pistons (28a, 28b) against their respective spring forces (44a, 44b). The first clutch (12a) and the second clutch (12b) are coaxial and arranged substantially in a mirror-symmetrical manner. The first piston chamber (34a) and the second piston chamber (34b) of the clutches (12a, 12b) have a common piston chamber rear wall (14). The first outer friction plate (26a) of the first clutch (12a) is connected to the first outer friction plate support (30a) in an anti-torsional manner, and the second outer friction plate (26b) of the second clutch (12b) is connected to the second outer friction plate support (30b) in an anti-torsional manner. The first inner friction plate... (22a) and the second inner friction plate (22b) are connected to a common inner friction plate support (20) in a torsional manner. The first inner friction plate (22a) and the second inner friction plate (22b) are fixed axially at the inner friction plate support (20), and each has an inner fixed region (45) and a radially outer friction region (49). These two regions are connected via a plurality of elastic connecting pieces (51), such that in the engaged state, the friction region (49) is axially offset relative to the fixed region (45) due to elastic deformation of the connecting pieces (51). The piston chamber rear wall (14) and the piston (28a, 28b) are axially arranged between the first inner friction plate (22a) and the second inner friction plate (22b), wherein the piston chamber rear wall (14) is internally supported at the inner friction plate support (22). This enables the application of the friction plate clutch in a high-speed range including a drive motor.

Description

Technical Field

[0001] This invention relates to a dual-clutch system comprising a first clutch and a second clutch, wherein each clutch is actuated by a hydraulic piston against a spring force. The first and second clutches are coaxial and arranged substantially mirror-symmetrically. The first and second piston chambers of the clutches share a common rear wall. The first outer friction plate of the first clutch is torsionally connected to a first outer friction plate support, and the second outer friction plate of the second clutch is torsionally connected to a second outer friction plate support. The first and second inner friction plates are torsionally connected to a common inner friction plate support. Furthermore, this invention relates to a drive system having such a dual-clutch system. Background Technology

[0002] A type of dual clutch is known from DE 10 2013 204 974 A1, and is used in a transmission system to alternately transmit drive torque to one of the two transmission input shafts between an internal combustion engine and a dual-clutch transmission.

[0003] In this dual clutch, both the inner and outer friction plates are arranged in torsion-resistant but axially movable inner and outer friction plate supports, and the piston chamber for the friction plate pair and piston spring is arranged radially inside the inner friction plate.

[0004] A clutch for an automatic transmission in a motor vehicle is known from DE 10 2016 014 672 A1, in which internal friction plates are axially fixed and torsionally connected to an internal friction plate support.

[0005] DE 10 2021 006 124 B3 describes a drive scheme comprising two drive motors and two drive wheels powered via reduction gears on a common drive shaft.

[0006] To date, conventional dual-clutch transmissions in electric drives operate at wheel speeds, i.e., according to the corresponding transmission stage, due to centrifugal force issues occurring in the high-speed range. This is partly due to the static actuation of the clutch mechanism, which leads to very high losses at high speeds, and partly due to high component stresses, which can become overcritical for individual clutch components at the high speeds of electric drives. Summary of the Invention

[0007] The object of this invention is to provide a dual clutch for an electric drive system of a motor vehicle as described in the preamble of claim 1, which enables application at high speeds (especially in drive motors). This dual clutch should primarily be used to enable a specific distribution of the torque of the drive motor on the drive wheels (i.e., so-called torque vectoring).

[0008] This invention derives from the features of the independent claims. Advantageous improvements and designs are the subject of the dependent claims.

[0009] According to claim 1, the objective is achieved by: a first inner friction plate and a second inner friction plate being connected at an inner friction plate support in an axially fixed manner, each having an inner fixed region and a radially outer friction region, the two regions being connected by a plurality of elastic connecting plates, such that in the engaged state, the friction region is axially offset relative to the fixed region when the connecting plates deform, and wherein the piston chamber rear wall and the piston are axially arranged between the first and second inner friction plates and are internally supported at the inner friction plate support.

[0010] According to the present invention, the inner friction plates are arranged in an axially fixed manner at the inner friction plate support, enabling the application of friction plate clutches in the high-speed range, i.e., for applications involving drive motors with speeds up to 20,000 rpm, which conventional friction plate clutches struggle to withstand. Therefore, with this invention, the friction plate clutch can operate at the motor speed of the drive motor, and the clutch speed does not need to be reduced by a front-mounted transmission. A transmission, or particularly a gearbox for reducing the high speed of (multiple) drive motors to the wheel speed of the vehicle, is provided on the output side of the dual clutch. This results in a relatively small torque that the friction plate clutches of the dual clutch need to transmit, requiring fewer friction plate pairs for force transmission, thus reducing the axial structural dimensions of the dual clutch. In turn, this allows the actuating piston, including a pressure chamber, to be arranged axially between two mirror-symmetrical clutches, enabling an extremely compact structural dimension of the dual clutch, both radially and radially, thereby creating structural space within the dual clutch for other components, particularly the planetary gear differential. The present invention enables a compact structure by allowing torque to be transmitted from both input and output on one side. The mirror-symmetric design of the torque-related clutch components ensures similar transmission characteristics and thus good adjustability of both clutches. Low-loss operation can be achieved with an electro-hydraulic clutch implementation because, in an electromechanical implementation, a high speed difference is generated between the actuator and the clutch piston, which must be transmitted via a thrust bearing.

[0011] According to an advantageous design of the invention, the rear wall of the piston chamber comprises a support disc fixed to the inner friction plate support and a guide sleeve formed radially outward. The guide sleeve includes two piston guiding devices for the piston on its outer circumference. A pressure chamber for introducing pressurized oil is designed between the piston and the rear wall of the piston chamber. This design, combined with a symmetrical structure, enables more reliable, precise, and easily controllable piston movement, and thus allows for reproducible controllability under electro-hydraulic actuation.

[0012] According to an advantageous improvement of the invention, each piston has an annular pressure protrusion extending axially and located radially outside a corresponding piston guide, via which corresponding inner and outer friction plates can be frictionally engaged with each other. This enables more precise and easier-to-control piston movement. Preferably, the outer piston guide is arranged at one-third of the radius of the pressure protrusion's application point, further enabling more reliable, precise, and easier-to-control piston movement.

[0013] According to an advantageous improvement of the invention, each clutch has a spring support fixed at the inner friction plate support for supporting the piston spring and forming a centrifugal oil chamber disposed between the piston and the spring support. Reliable centrifugal force compensation is achieved by arranging the centrifugal oil chamber between the piston and the spring support, resulting in more precise piston actuation, which is particularly important for applications in electric drives due to the high rotational speeds. Simultaneously, in this improvement, the piston spring is located inside the centrifugal oil chamber, further improving the structural compactness. Preferably, the centrifugal oil chamber is sealed relative to the surrounding environment via a sealing ring, such that the spring support also serves to separate the centrifugal oil chamber from the space containing the friction plate.

[0014] According to an advantageous improvement of the invention, the internal friction plate support is designed as a two-piece unit, consisting of two support elements arranged sequentially in the axial direction. Evenly spaced fastening screws securely connect the support elements, the piston chamber rear wall, the spring support, the internal friction plate, the spacer, and the support bracket, which serves as a mating support against the axial pressure generated by the piston. This ensures an easy-to-install, fixed connection, while allowing for simple disassembly and replacement of damaged components in case of failure.

[0015] Furthermore, this objective is achieved through a drive system using a dual clutch as described above, comprising two drive motors. Here, the dual clutch can be directly coupled to the drive motors without the need for an intermediate reduction gear; thus, the dual clutch only needs to transmit a relatively small torque, which is feasible through the dual clutch design according to the invention. Therefore, a very compact drive system is provided with a smaller number of friction plates for torque transmission.

[0016] According to an advantageous improvement to this design, the inner friction plate support can be coupled to the first drive motor. Preferably, coupling is achieved via a claw-shaped clutch between the rotor of the drive motor and the inner friction plate support. According to the invention, this coupling eliminates the need for an intermediate transmission, allowing the dual clutch to rotate at the speed of the drive motor, i.e., in the range of 10,000 rpm to 20,000 rpm. As mentioned above, due to the high rotational speed, this drive system can be achieved using the dual clutch designed according to the invention. Due to the high rotational speed, the design according to the invention transmits only a relatively small amount of torque in the dual clutch, allowing the number of friction plate pairs to be kept low, thereby enabling a very compact overall structure consisting of two drive motors and a dual clutch arranged therebetween.

[0017] According to an advantageous improvement to this design, the internal friction plate support can be coupled to the first drive motor, thus eliminating the need for a transmission gearbox in a dual clutch to reduce speed.

[0018] According to an advantageous improvement of this design, the first outer friction plate bracket provides power output to the first drive wheel via a first output shaft, and the second outer friction plate bracket provides power output to the second drive wheel via a second output shaft, wherein the first and second drive wheels correspond to a common drive shaft. This design enables an extremely compact axial structure. Preferably, a transmission gearbox is mounted upstream of the drive wheels to reduce the high speed of the drive motor to the speed range of the drive wheels. Attached Figure Description

[0019] Further advantages, features, and details are derived from the following description, in which an embodiment is described in detail with reference to the accompanying drawings, if necessary. Identical, similar, and / or functionally identical parts are labeled with the same reference numerals.

[0020] It shows that:

[0021] Figure 1 A partial axial sectional view of a dual-clutch transmission that includes the surrounding environment;

[0022] Figure 2 for Figure 1 A partial axial sectional view of a dual-clutch transmission;

[0023] Figure 3 for Figure 1 and Figure 2 Axial schematic diagram of a dual clutch;

[0024] Figure 4 This is a view of the internal friction plate;

[0025] Figure 5 This is a schematic diagram of a drive system that includes a dual clutch and two drive motors. Detailed Implementation

[0026] exist Figure 1 , Figure 2 and Figure 3 The image shows a dual clutch 10, which consists of two clutches 12a and 12b that are sequentially constructed and arranged axially in a mirror-symmetrical manner relative to the rear wall 14 of the piston chamber. Figure 2 Enlarged display Figure 1 Details of the left clutch 12a, and the right clutch 12b are constructed in a mirror-symmetrical manner.

[0027] The input torque is introduced into the dual clutch 10 via the input shaft 16 and transmitted to the internal friction plate support 20, which consists of two support elements 18a and 18b. The piston chamber rear wall 14, which is generally disc-shaped, is embedded between the two support elements 18a and 18b.

[0028] Each of the two clutches 12a and 12b has several internal friction plates 22a and 22b (with spacers 24a arranged between them). Figure 1 For clarity, the spacer in the right clutch 12b is not marked. It consists of several outer friction plates 26a and 26b that can generate frictional contact with the inner friction plates 22a and 22b.

[0029] The outer friction plate 26a of the first clutch 12a shown on the left is fixed / held in a first outer friction plate bracket 30a in a torsion-resistant but axially displaceable manner. The first outer friction plate bracket 30a is part of the first output shaft 32. The outer friction plate 26b of the second clutch 12b shown on the right is fixed / held in the second outer friction plate bracket 30b in the same manner in a torsion-resistant but axially displaceable manner. The second outer friction plate bracket 30b is part of the second output shaft 36.

[0030] Two clutches 12a and 12b are actuated by two pistons 28a and 28b, which are axially guided by an outer piston guide 29a at the rear wall 14 of a common piston chamber and an inner piston guide 29b at the inner friction plate support 20. Two piston chambers 34a and 34b are designed between the rear wall 14 of the piston chamber and the two pistons 28a and 28b. Each piston chamber is subjected to pressure by pressurized oil, allowing the pistons 28a and 28b to move axially from the rear wall 14 of the piston chamber. Two annular pressure protrusions 38a and 38b press against a friction plate assembly consisting of inner friction plates 22a and 22b and interleaved outer friction plates 26a and 26b. Here, the outer piston guide 29a of the pistons 28a and 28b is located at the outer third of the radius of the force application point of the pressure protrusions 38a and 38b.

[0031] Two support brackets 40a are mounted on the two support elements 18a, 18b that constitute the inner friction plate support 22. The support brackets act as mating supports against the axial pressure applied by the two annular pressure protrusions 38a, 38b, and thus form a frictional engagement between the inner friction plates 22a, 22b and the outer friction plates 26a, 26b that are interposed therewith.

[0032] Two spring supports 42a and 42b are provided between pistons 28a and 28b and two corresponding clutches 12a and 12b, and the spring supports are fixed to the inner friction plate supports 22. Two centrifugal oil chambers 46a and 46b extend between each spring support 42a and 42b and the corresponding piston 28a and 28b. The centrifugal oil chambers are filled with unpressurized oil and compensate for the additional pressure increase caused by the centrifugal force in the piston chambers 34a and 34b, because the centrifugal oil chambers 46a and 46b are arranged on the axial side of pistons 28a and 28b opposite to piston chambers 34a and 34b. The centrifugal oil chambers 46a and 46b are sealed relative to piston chambers 34a and 34b and the space containing friction plates 22 and 26 by means of sealing rings 43. Two piston springs 44a and 44b are arranged inside the centrifugal oil chambers 46a and 46b. When the oil pressure in the corresponding piston chambers 34a and 34b decreases, the piston springs move the corresponding pistons 28a and 28b toward the rear wall 14 of the piston chamber.

[0033] The support brackets 40a and 40b, the inner friction plates 22a and 22b, together with the spacers 24a and 24b arranged between them, the two support elements 18a and 18b, and the piston chamber rear wall 14 arranged between them, are securely tightened together by evenly spaced fastening screws 48, so that the inner friction plates 22a and 22b cannot be moved axially.

[0034] With clutches 12a and 12b disengaged, piston chambers 34a and 34b are unpressurized, causing piston springs 44a and 44b to push pistons 28a and 28b towards the rear wall 14 of the piston chamber. In this situation, axial clearance exists between the inner friction plates 22a and 22b and the adjacent outer friction plates 26a and 26b. Figure 4As shown, the inner friction plates 22a and 22b each consist of a fixed area 45 located radially inward, including an opening 47 for the fastening screw 48 to pass through, and an annular friction area 49 located radially outward. This friction area on both sides of the inner friction plates 22a and 22b is used for frictional engagement with the friction areas of the outer friction plates 26a and 26b located at the same radial height. The fixed area 45 and friction area 49 of each inner friction plate 22a and 22b are interconnected by several flexible, S-shaped connecting pieces 51. In the disengaged state of the clutches 12a and 12b, the inner friction plates 22a and 22b are flat discs extending precisely in the radial direction. If pressurized oil is introduced into the corresponding piston chamber 34a, the clutch 12a is engaged in such a way that the piston 28a moves against the force of the piston spring 44a, causing the pressure protrusion 38a of the piston 28a to press against the friction plate assembly composed of the inner friction plate 22a and the outer friction plate 26a, which is supported at the support bracket 40a. The outer friction plate 26a can move axially together with the outer friction plate support 30a, but the inner friction plate 22a cannot. The inner friction plate is mounted on the inner friction plate support 20 in an axially fixed manner. Here, when the friction area 49 of the inner friction plate 22a moves axially together with the outer friction plate 26a through the pressure protrusion 38a, the S-shaped connecting plate 51 undergoes elastic deformation, thereby creating a frictional connection between the inner friction plate 22a and the outer friction plate 26a, and thus causing the clutch 12a to enter the engaged state.

[0035] Figure 5 The application of the dual clutch 10 as part of the drive system 50 is shown, which includes two drive motors 52a and 52b, a planetary gear differential 54, two planetary gear sets 56a and 56b, and two drive wheels 58a and 58b.

[0036] The first drive motor 52a is connected to the ring gear 53 of the planetary gear differential 54, and the sun gear of the planetary gear differential is connected to the planetary gear set 56b via... Figure 5 The right drive wheel 58b is coupled. The planet carrier of the planetary gear differential 54 is connected to the second clutch 12b via the second output shaft 36 and... Figure 5 The planetary gear set 56a is connected to the left-hand drive wheel 58a.

[0037] The input shaft 16 of the dual clutch 10 is coupled to the second drive motor 52b via a claw clutch 57. The input shaft 16 is connected to the first output shaft 32 via an actuating first clutch 12a, and the first output shaft is also connected to... Figure 5 The right drive wheel 58b is coupled.

[0038] When the first clutch 12a is engaged (and for this purpose the second clutch 12b remains disengaged), the input shaft 16 of the second drive motor 52b is connected to the first output shaft 32 such that the torque of the second drive motor 52b is introduced to the first output shaft 32 by passing over the second output shaft 36, and thus is introduced into Figure 5 The right drive wheel 58b.

[0039] Conversely, if the second clutch 12b engages (and for this disengages the first clutch 12a), the torque of the second drive motor 52b is introduced via the input shaft 16 to the second output shaft 36, and thus is introduced into... Figure 5 The left drive wheel 58a is located in the center. This enables torque vectoring operation, in which different torques can be selectively delivered to the two output shafts 32, 36 or the drive wheels 58a, 58b.

[0040] While the invention has been described and explained in more detail through preferred embodiments, it is not limited to the disclosed examples, and those skilled in the art can derive other variations therefrom without departing from the scope of protection of the invention. Therefore, it is apparent that numerous variations are possible. It is also clear that the above embodiments are merely illustrative examples and should not be construed in any way as limiting, for example, the scope of protection, applicability, or configuration of the invention. Rather, the foregoing description and accompanying drawings enable those skilled in the art to practice the exemplary embodiments in a specific manner, wherein various changes can be made by those skilled in the art, recognizing the disclosed inventive concept, such as changes in the function or arrangement of the various elements described in the exemplary embodiments, without departing from the scope of protection defined by the claims and their legal equivalents (as further explained in the description).

[0041] List of reference numerals

[0042] 10 Dual Clutch

[0043] 12a, b clutches

[0044] 14 Piston chamber rear wall

[0045] 16-input axis

[0046] 18a and 18b support elements

[0047] 20 Internal Friction Plate Support

[0048] 22a, 22b internal friction plates

[0049] 24a and 24b spacers

[0050] 26a and 26b external friction plates

[0051] 28a and 28b pistons

[0052] 29a, 29b Piston Guide Devices

[0053] 30a and 30b external friction plate supports

[0054] 32 First Output Shaft

[0055] 34a, 34b piston chambers

[0056] 36 Second Output Shaft

[0057] 38a, 38b pressure protrusions

[0058] 40a, 40b support brackets

[0059] 42a, 42b Spring Supports

[0060] 43 sealing ring

[0061] 44a, 44b piston springs

[0062] 45 Fixed Area

[0063] Centrifugal oil chambers 46a and 46b

[0064] 47 openings

[0065] 48 Fastening Screws

[0066] 49 Friction Area

[0067] 50 drive system

[0068] 51 connecting piece

[0069] 52a and 52b drive motors

[0070] 53 gear ring

[0071] 54 planetary gear differential

[0072] 56a and 56b planetary gear sets

[0073] 57 Claw Clutch

[0074] 58a and 58b drive wheels

Claims

1. A dual-clutch (10) for an electric drive system of a motor vehicle, comprising a first clutch (12a) and a second clutch (12b), wherein, - The first clutch (12a) and the second clutch (12b) are each actuated by means of hydraulic pistons (28a, 28b) against spring forces (44a, 44b). - The first clutch (12a) and the second clutch (12b) are coaxial and arranged substantially in a mirror-symmetrical manner. The first piston chamber (34a) and the second piston chamber (34b) of the clutch (12a, 12b) have a common piston chamber rear wall (14). - The first outer friction plate (26a) of the first clutch (12a) is connected to the first outer friction plate support (30a) in an anti-torsional manner, and the second outer friction plate (26b) of the second clutch (12b) is connected to the second outer friction plate support (30b) in an anti-torsional manner. - The first internal friction plate (22a) and the second internal friction plate (22b) are connected to the common internal friction plate support (20) in an anti-torsional manner. Its features are, The first internal friction plate (22a) and the second internal friction plate (22b) are fixed axially at the internal friction plate support (20), and each has a fixed area (45) located radially inward and a friction area (49) located radially outward. The fixed area and the friction area are connected by a plurality of elastic connecting pieces (51), so that in the engaged state, the friction area (49) is offset axially relative to the fixed area (45) when the connecting pieces (51) elastically deform. Furthermore, the piston cavity rear wall (14) and the piston (28a, 28b) are arranged axially between the first inner friction plate (22a) and the second inner friction plate (22b), wherein the piston cavity rear wall (14) is supported on the inner side at the inner friction plate support (20).

2. The dual clutch according to claim 1, Its features are, The piston chamber rear wall (14) consists of a support disc fixed at the inner friction plate support and a guide sleeve formed radially outward. The guide sleeve includes two piston guide devices for the piston (28a, 28b) on its outer periphery. The piston chamber (34a, 34b) between the piston (28a, 28b) and the piston chamber rear wall (14) is designed to introduce pressurized oil.

3. The dual clutch according to claim 2, Its features are, Each of the pistons (28a, 28b) has an annular pressure protrusion (38a, 38b) that is located radially outside the corresponding radially outer piston guide (29a) and extends axially, through which the corresponding inner friction plate (22a, 22b) and the outer friction plate (26a, 26b) can be frictionally engaged with each other.

4. The dual clutch according to claim 3, Its features are, The outer piston guide device (29a) of the piston (28a, 28b) is arranged at one-third of the radius of the force application point of the pressure protrusion (38a, 38b).

5. The dual clutch according to any one of claims 2 to 4, Its features are, Each of the clutches (12a, 12b) has a spring support (42a, 42b) fixed at the inner friction plate support (20) to support the piston spring (44a, 44b) and form a centrifugal oil chamber (46a, 46b) respectively arranged between the piston (28a, 28b) and the spring support (42a, 42b).

6. The dual clutch according to claim 5, Its features are, The centrifugal oil chambers (46a, 46b) are sealed relative to the surrounding environment via sealing rings (43).

7. The dual clutch according to any one of the preceding claims, Its features are, The internal friction plate support (20) is designed as a two-piece unit and consists of two support elements (18a, 18b) arranged sequentially in the axial direction. The support elements (18a, 18b), the piston chamber rear wall (14), the spring support (42a, 42b), the internal friction plate (22a, 22b), the spacer (24a, 24b), and the support bracket (40a, 40b) are fixedly connected to each other by evenly spaced fastening screws (48). The support bracket serves as a mating support for the axial pressure generated by the piston (28a, 28b).

8. An electric drive system comprising two drive motors (52a, 52b) and a dual clutch (10) according to any one of the preceding claims. Its features are, The dual clutch (10) can be directly coupled to the drive motor (52a, 52b) without the need for an intermediate reduction gear.

9. The electric drive system according to claim 8, Its features are, The internal friction plate support (20) is coupled to the first drive motor (52b) via a clutch, preferably a claw clutch.

10. The electric drive system according to claim 8 or 9, Its features are, The first outer friction plate bracket (30a) provides power output to the first drive wheel (58b) via the first output shaft (32), and the second outer friction plate bracket (30b) provides power output to the second drive wheel (58a) via the second output shaft (36), wherein the first and second drive wheels (58a, 58b) correspond to a common drive shaft.

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