Dual clutch and the drive system equipped with it

Abstract

A dual clutch (10) and a drive system with 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 a spring force (44a, 44b), the first clutch (12a) is arranged coaxially and substantially mirror-symmetrically to the second clutch (12b), a first (34a) and a second piston chamber (34b) of the clutches (12a, 12b) have a common piston chamber rear wall (14), first outer plates (26a) of the first clutch (12a) are rotationally fixed to a first outer plate holder (30a) and second outer plates (26b) of the second clutch (12b) are rotationally fixed to a second outer plate holder (30b), first inner plates (22a) and second inner plates (22b) are connected to a common The inner lamella carriers (20) are connected in a rotationally fixed manner, are characterized by this.that the first (22a) and the second inner lamellae (22b) are axially fixed to the inner lamella carrier (20) and each have inner mounting areas (45) and radially outer friction areas (49) which are connected via a number of resilient connecting webs (51), such that the friction areas (49) are axially offset relative to the mounting areas (45) in the coupled state under elastic deformation of the connecting webs (51), and wherein the piston chamber rear wall (14) and the pistons (28a, 28b) are arranged axially between the first (22a) and second (22b) inner lamellae, the piston chamber rear wall (14) being supported on the inner side by the inner lamella carrier (22). This enables the use of multi-plate clutches in the high-speed range with electric drive motors.

Description

[0001] The invention relates to a dual clutch with a first clutch and a second clutch, wherein the first clutch and the second clutch are each actuated by means of hydraulic pistons against a spring force, the first clutch is arranged coaxially and substantially mirror-symmetrically to the second clutch, a first and a second piston chamber of the clutches have a common piston chamber rear wall, first outer plates of the first clutch are connected in a rotationally fixed manner to a first outer plate holder and second outer plates of the second clutch are connected in a rotationally fixed manner to a second outer plate holder, first inner plates and second inner plates are connected in a rotationally fixed manner to a common inner plate carrier. The invention further relates to a drive system with such a dual clutch.

[0002] DE 10 2015 217 071 A1 discloses a multiple clutch device with a first and a second disk carrier and with a first and a second friction pack.

[0003] JP H07-224 864 A describes a method for operating a hydraulic clutch, wherein the clutch has two clutch parts.

[0004] Such a dual clutch is known from DE 10 2013 204 974 A1 and is used to supply the drive torque alternatively to one of two transmission input shafts in the drive train between an internal combustion engine and a dual clutch transmission.

[0005] In this dual clutch, both the inner and outer plates are arranged in rotationally fixed but axially movable inner and outer plate carriers, and piston chambers for the plate pairs and piston springs are arranged radially inside the inner plates.

[0006] From DE 10 2016 014 672 A1 a clutch for an automatic transmission of a motor vehicle is known in which internal plates are connected axially and rotationally fixed to an inner plate carrier.

[0007] DE 10 2021 006 124 B3 describes a drive concept with two electric drive motors and two drive wheels of a common drive axle actuated by reduction gears.

[0008] Conventional dual clutches in electric motor drives have so far been operated at wheel speed, i.e., after a corresponding gear ratio, due to the centrifugal force problems that occur at high speeds. The reason for this is, on the one hand, the stationary actuation of the clutch mechanism, which would lead to very high losses at higher speeds, and, on the other hand, the high component stresses, which can become supercritical for individual clutch components at the high speeds of electric motor drives.

[0009] The object of the invention is to provide a dual clutch for an electric drive system of a motor vehicle according to the preamble of claim 1, which enables use at high speeds, which are particularly common in electric drive motors. Above all, the dual clutch is intended to be used to enable a defined distribution of torque from an electric drive motor to the drive wheels (so-called torque vectoring).

[0010] The invention is based on the features of the independent claims. Advantageous developments and refinements are the subject of the dependent claims.

[0011] The object is achieved according to claim 1 in that the first and the second inner plates are connected axially fixed to the inner plate carrier and each have inner fastening regions and radially outer friction regions which are connected via a number of resilient connecting webs, so that the friction regions are axially offset in relation to the fastening regions in the coupled state with deformation of the connecting webs, and wherein the piston chamber rear wall and the pistons are arranged axially between the first and second inner plates and are supported on the inside on the inner plate carrier.

[0012] The inventive arrangement of the inner plates, axially fixed to an inner plate carrier, makes the use of multi-plate clutches possible in the high-speed range, i.e., for applications with electric drive motors operating at up to 20,000 rpm, a situation where conventional multi-plate clutches are difficult to design with a fixed speed. The invention thus allows the multi-plate clutch to operate at the engine speed of the electric drive motor(s), eliminating the need to reduce the clutch speed by means of an upstream transmission.A gearbox or, in particular, a gear stage for reducing the high speeds of the drive engine(s) to the speeds of the motor vehicle's wheels is provided on the output side of the dual clutch, whereby the torque that the multi-plate clutches of the dual clutch have to transmit is comparatively low, so that fewer pairs of plates are required for power transmission, which reduces the axial size of the dual clutch. This, in turn, enables the actuating pistons with pressure chamber to be arranged axially between the two mirror-symmetrical clutches and enables an extremely compact size of the dual clutch, also in radial terms, so that space is created radially within the dual clutch for additional components, in particular a planetary gear differential. The invention also enables a compact design because the transmission torques can be introduced and discharged on one side.The mirror-symmetrical design of the transmission-relevant clutch components ensures similar transmission characteristics and thus good controllability of both clutches. An electro-hydraulic clutch design enables low-loss operation, since an electromechanical design would result in high differential speeds between the actuator and the clutch piston, which would have to be transmitted via an axial bearing.

[0013] According to an advantageous embodiment of the invention, the piston chamber rear wall consists of a support disk attached to the inner disk carrier and a radially externally formed guide sleeve with two piston guides for the pistons formed on its outer circumference. Pressure chambers are formed for the introduction of pressurized oil between the pistons and the piston chamber rear wall. This design, together with the symmetrical structure, enables more reliable, more precise, and better controllable piston movements and thus reproducible control quality with electrohydraulic control.

[0014] According to an advantageous development of the invention, each piston has an annular thrust projection extending axially radially outside the respective piston guide, via which the respective inner and outer plates can be brought into frictional engagement with one another. This enables more precise and better controllable piston movements. Preferably, the outer piston guides of the pistons are arranged in the outer third of the force application point radii of the thrust projections, which enables more reliable, more precise, and better controllable piston movements.

[0015] According to the invention, the clutches each have a spring support fixed to the inner plate carrier for supporting a piston spring and for forming a centrifugal oil chamber arranged between the piston and the spring support. The arrangement of centrifugal oil chambers between the pistons and the spring supports ensures reliable centrifugal force compensation, resulting in more precise piston control, which is particularly important given the high speeds involved in electric drives. At the same time, in this development, the piston spring is located inside the centrifugal oil chamber, further increasing the compactness of the design. The centrifugal oil chambers are preferably sealed from the environment by means of sealing rings, so that the spring supports also serve to separate the centrifugal oil chambers from the space containing the plates.

[0016] According to the invention, the inner plate carrier is constructed in two parts and consists of two support elements arranged axially one behind the other. Evenly spaced fixing screws firmly connect the support elements, the piston chamber rear wall, the spring supports, the inner plates, the spacers, and the counterholders as counterbearings for the axial compressive force generated by the pistons. This ensures a secure connection that is easy to install, yet allows for easy disassembly to replace defective components in the event of damage.

[0017] The problem is further solved by a drive system with two electric drive motors using a dual clutch, as described above. The dual clutch can be coupled directly to the drive motors without the need for intermediate reduction gears, thus requiring only comparatively lower torques to be transmitted by the dual clutch, which is made possible by the inventive design of the dual clutch. The smaller number of plates for torque transmission therefore provides a very compact drive system.

[0018] According to an advantageous development of this embodiment, the inner disk carrier can be coupled to a first electric drive motor. The coupling is preferably effected via a claw clutch between the rotor of the electric drive motor and the inner disk carrier. According to the invention, such a coupling is effected without an intermediate transmission, so that the dual clutch rotates at the speed of the electric drive motor, i.e., in the range of 10,000-20,000 rpm. As already explained above, such a drive system is feasible due to the high speeds achieved by the dual clutch designed according to the invention.Due to the high speed in the dual clutch, the design according to the invention transmits only a relatively low torque, so that the number of plate pairs can be kept low and thus the overall construction consisting of two electric drive motors and the dual clutch arranged between them is very compact.

[0019] According to an advantageous further development of this design, the inner disk carrier can be coupled to a first electric drive motor, i.e. without a transmission gear for reducing the speed in the double clutch.

[0020] According to an advantageous further development of this design, the first outer disk holder forms an output to a first drive gear via a first output shaft, and the second outer disk holder forms an output to a second drive gear via a second output shaft, with the first and second drive gears being assigned to a common drive axle. This design enables a very compact axial design of the overall structure. Preferably, transmission gears are installed upstream of the drive gears to reduce the high speed of the electric drive motors to the speed range of the drive gears.

[0021] Further advantages, features, and details will become apparent from the following description, which describes an exemplary embodiment in detail—with reference to the drawings, if appropriate. Identical, similar, and / or functionally equivalent parts are provided with the same reference numerals.

[0022] They show: Fig. 1: a perspective axial partial section of a double clutch with surroundings; Fig. 2: an axial section of the double clutch of Fig. 1; Fig. 3: a schematic representation of the double clutch of Fig. 1 and Fig. 2; Fig. 4: a view of an inner lamella; Fig. 5: a schematic representation of a drive system with the dual clutch and two electric drive motors.

[0023] In the Fig. 1, Fig. 2 and Fig. 3 shows a double clutch 10 which consists of two clutches 12a, 12b which are designed and arranged axially one behind the other with respect to a piston chamber rear wall 14 in a mirror-symmetrical manner. Fig. 2 shows the left coupling 12a from Fig. 1 enlarged in detail, the right coupling 12b is constructed in mirror image.

[0024] An input torque is introduced into the dual clutch 10 via an input shaft 16 and transmitted to an inner disk carrier 20 consisting of two carrier elements 18a, 18b. The essentially disc-like piston chamber rear wall 14 is fitted between the two carrier elements 18a, 18b.

[0025] The two clutches 12a, 12b each consist of a number of inner plates 22a, 22b, between which spacers 24a (the spacers in the right clutch 12b are in Fig. 1 not designated for reasons of clarity) and a number of outer plates 26a, 26b, which can be brought into frictional contact with the inner plates 22a, 22b.

[0026] The outer plates 26a of the first clutch 12a shown on the left are held in a first outer plate holder 30a in a rotationally fixed but axially displaceable manner. The first outer plate holder 30a is part of a first output shaft 32. The outer plates 26b of the second clutch 12b shown on the right are held in a second outer plate holder 30b in a similarly rotationally fixed but axially displaceable manner. The second outer plate holder 30b is part of a second output shaft 36.

[0027] The two clutches 12a, 12b are actuated by two pistons 28a, 28b, which are axially guided via an outer piston guide 29a on the common piston chamber rear wall 14 and an inner piston guide 29b on the inner disk carrier 20. Between the piston chamber rear wall 14 and the two pistons 28a, 28b, two piston chambers 34a, 34b are formed, which are individually pressurized with oil, so that the pistons 28a, 28b can move axially from the piston chamber rear wall 14 and press with two annular pressure projections 38a, 38b against the disk packs consisting of the inner disks 22a, 22b and the outer disks 26a, 26b alternating with them. The outer piston guides 29a of the pistons 28a, 28b are arranged in the outer third of the force application point radii of the pressure projections 38a, 38b.

[0028] Two counterholders 40a are attached to the two support elements 18a, 18b forming the inner disk carrier 22, which act as counterbearings for the axial pressure forces applied by the two annular pressure projections 38a, 38b and thus cause a frictional engagement between the inner disks 22a, 22b and the outer disks 26a, 26b alternating therewith.

[0029] Between the pistons 28a, 28b and the two associated clutches 12a, 12b, two spring supports 42a, 42b are provided, which are attached to the inner disk carrier 22. Between each spring support 42a, 42b and an associated piston 28a, 28b, extend two centrifugal oil chambers 46a, 46b, which are filled with unpressurized oil and compensate for the additional pressure increase caused by the centrifugal forces in the piston chambers 34a, 34b, since the centrifugal oil chambers 46a, 46b are arranged on the axial sides of the pistons 28a, 28b opposite the piston chambers 34a, 34b. The centrifugal oil chambers 46a, 46b are sealed from the piston chambers 34a, 34b and the chamber containing the disks 22, 26 by means of sealing rings 43. Two piston springs 44a, 44b are arranged inside the centrifugal oil chambers 46a, 46b, which move the respective piston 28a, 28b in the direction of the piston chamber rear wall 14 when the oil pressure in the associated piston chamber 34a, 34b is reduced.

[0030] The counterholders 40a, 40b, the inner plates 22a, 22b with the spacers 24a, 24b arranged therebetween, and the two support elements 18a, 18b with the piston chamber rear wall 14 arranged therebetween are firmly screwed together by means of evenly spaced fixing screws 48, so that the inner plates 22a, 22b are not axially displaceable.

[0031] When the clutches 12a, 12b are disengaged, the piston chambers 34a, 34b are depressurized, so that the piston springs 44a, 44b press the pistons 28a, 28b in the direction of the piston chamber rear wall 14. In this case, axial gaps exist between the inner plates 22a, 22b and the adjacent outer plates 26a, 26b. As shown in Fig. As shown in Figure 4, the inner plates 22a, 22b each consist of a radially inner fastening area 45 with openings 47 for the passage of the fixing screws 48 and a radially outer annular friction area 49, which serves on both sides of the inner plates 22a, 22b to enter into frictional engagement with friction areas of the outer plates 26a, 26b located at the same radial height. The fastening area 45 and the friction area 49 of each inner plate 22a, 22b are connected to one another by a number of flexible, S-shaped connecting webs 51. In the open state of the clutches 12a, 12b, the inner plates 22a, 22b are flat discs that extend precisely in the radial direction.If a clutch 12a is engaged by directing pressurized oil into the respective piston chamber 34a, this moves the piston 28a against the force of the piston spring 44a, so that the pressure projection 38a of the piston 28a presses against the disk pack consisting of inner disks 22a and outer disks 26a, which in turn are supported on the counterholder 40a. While the outer disks 26a can move axially in the outer disk holder 30a, this does not apply to the inner disks 22a, which are axially fixedly mounted on the inner disk carrier 20. The S-shaped connecting webs 51 deform elastically when the friction areas 49 of the inner plates 22a are axially displaced by the pressure projection 38a together with the outer plates 26a, whereby a friction connection is created between the inner plates 22a and the outer plates 26a and thus the clutch 12a engages.

[0032] In Fig. 5 shows an application of the dual clutch 10 as a component of a drive system 50 with two electric drive motors 52a, 52b, a planetary differential gear 54, two planetary gear sets 56a, 56b and two drive wheels 58a, 58b.

[0033] A first electric drive machine 52a is connected to a ring gear 53 of the planetary differential gear 54, the sun gear of which is connected via the planetary gear set 56b to the Fig. 5 right drive gear 58b. The planet carriers of the planetary differential gear 54 are connected via the second output shaft 36 to the second clutch 12b and to the planetary gear set 56a of the Fig. 5 left drive wheel 58a.

[0034] An input shaft 16 of the dual clutch 10 can be coupled to the second electric drive motor 52b via a claw clutch 57. The input shaft 16 is connected by actuation of the first clutch 12a to the first output shaft 32, which is also connected via the planetary gear set 56b to the Fig. 5 right drive wheel 58b is coupled.

[0035] When the first clutch 12a is engaged (and the second clutch 12b remains disengaged), the input shaft 16 of the second electric drive motor 52b is connected to the first output shaft 32 in such a way that the torque of the second electric drive motor 52b is bypassed by the second output shaft 36 and is fed into the first output shaft 32 and thus into the Fig. 5 right drive wheel 58b is initiated.

[0036] If, however, alternatively, the second clutch 12b is engaged (and the first clutch 12b is disengaged for this purpose), the torque of the second electric drive machine 52b is transferred via the input shaft 16 into the second output shaft 36 and thus into the Fig. 5 left drive gear 58a. This enables torque vectoring operation, in which different torques can be specifically supplied to the two output shafts 32, 36 or drive gears 58a, 58b.

[0037] Although the invention has been illustrated and explained in detail by means of preferred embodiments, the invention is not limited by the disclosed examples, and other variations may be derived therefrom by those skilled in the art without departing from the scope of the invention. It is therefore clear that a multitude of possible variations exist. It is also clear that the embodiments mentioned by way of example are truly only examples and should not be construed as limiting the scope, possible applications, or configuration of the invention in any way.Rather, the preceding description and the description of the figures enable the person skilled in the art to implement the exemplary embodiments in concrete terms, whereby the person skilled in the art, with knowledge of the disclosed inventive concept, can make various changes, for example with regard to the function or the arrangement of individual elements mentioned in an exemplary embodiment, without departing from the scope of protection defined by the claims and their legal equivalents, such as further explanations in the description. List of reference symbols 10 Dual clutch 12a,b couplings 14 Piston chamber rear wall 16 Input shaft 18a,b support elements 20 inner disc carriers 22a,b inner slats 24a,b spacers 26a,b outer slats 28a,b piston 29a,b piston guides 30a,b outer slat holder 32 first output shaft 34a,b piston chamber 36 second output shaft 38a,b pressure projections 40a, b Counterholder 42a,b spring supports 43 sealing rings 44a,b piston springs 45 Mounting area 46a, 46b Centrifugal oil rooms 47 openings 48 fixing screws 49 Friction area 50 drive system 51 connecting bridges 52a, b electric drive machines 53 ring gear 54 planetary differential gears 56a, b Planetary gear sets 57 Claw coupling 58a, b drive wheels

Claims

[1] Double clutch (10) for an electric drive system of a motor vehicle with a first clutch (12a) and a second clutch (12b), wherein - the first clutch (12a) and the second clutch (12b) can each be actuated by means of hydraulic pistons (28a, 28b) against a spring force (44a, 44b), - the first coupling (12a) is arranged coaxially and substantially mirror-symmetrically to the second coupling (12b), - a first (34a) and a second piston chamber (34b) of the clutches (12a, 12b) have a common piston chamber rear wall (14), - first outer plates (26a) of the first clutch (12a) are connected in a rotationally fixed manner to a first outer plate holder (30a) and second outer plates (26b) of the second clutch (12b) are connected in a rotationally fixed manner to a second outer plate holder (30b), - first inner plates (22a) and second inner plates (22b) are connected in a rotationally fixed manner to a common inner plate carrier (20), wherein the first (22a) and the second inner plates (22b) are axially fixed to the inner plate carrier (20) and each have radially inner fastening regions (45) and radially outer friction regions (49) which are connected via a number of resilient connecting webs (51), so that the friction regions (49) in the coupled state are axially offset relative to the fastening regions (45) with elastic deformation of the connecting webs (51), and wherein the piston chamber rear wall (14) and the pistons (28a, 28b) are arranged axially between the first (22a) and second (22b) inner plates, wherein the piston chamber rear wall (14) is supported on the inside on the inner plate carrier (20), wherein the clutches (12a, 12b) each have a spring support (42a, 42b) fixed to the inner plate carrier (20) for supporting a piston spring (44a, 44b) and for forming a centrifugal oil chamber (46a, 46b) arranged between the piston (28a, 28b) and the spring support (42a, 42b), and wherein the inner plate carrier (20) is formed in two parts and consists of two carrier elements (18a, 18b) arranged axially one behind the other, wherein equally spaced fixing screws (48) firmly connect the carrier elements (18a, 18b), the piston chamber rear wall (14), the spring supports (42a, 42b), the inner plates (22a, 22b), spacers (24a, 24b) arranged between the inner plates (22a, 22b), and counterholders (40a, 40b) as a counterbearing for an axial compressive force generated by the pistons (28a, 28b). [2] Double clutch according to claim 1, characterized by that the piston chamber rear wall (14) consists of a support disc fastened to the inner disk carrier and a guide sleeve formed radially on the outside with two piston guides for the pistons (28a, 28b) formed on its outer circumference, wherein the piston chambers (34a, 34b) are designed for the introduction of pressurized oil between the pistons (28a, 28b) and the piston chamber rear wall (14). [3] Double clutch according to claim 2, characterized by that each piston (28a, 28b) has an annular pressure projection (38a, 38b) extending axially radially outside the respective radially outer piston guide (29a), via which the respective inner (22a, 22b) and outer plates (26a, 26b) can be brought into frictional engagement with one another. [4] Double clutch according to claim 3, characterized by that the outer piston guides (29a) of the pistons (28a, 28b) are arranged in the outer third of the force application point radii of the pressure projections (38a, 38b). [5] Double clutch according to one of the preceding claims, characterized by that the centrifugal oil chambers (46a, 46b) are sealed from the environment by sealing rings (43). [6] Electric drive system with two electric drive motors (52a, 52b) and a double clutch (10) according to one of the preceding claims, characterized bythat the double clutch (10) can be coupled directly to the drive machines (52a, 52b) without the interposition of reduction gears. [7] Electric drive system according to claim 6, characterized by that the inner disk carrier (20) can be coupled to a first electric drive machine (52b) via a clutch, preferably a claw clutch. [8] Electric drive system according to claim 6 or 7, characterized by in that the first outer disk holder (30a) forms an output to a first drive wheel (58b) via a first output shaft (32) and the second outer disk holder (30b) forms an output to a second drive wheel (58a) via a second output shaft (36), the first and second drive wheels (58a, 58b) being assigned to a common drive axle.

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