Torque transmission device with a thermal insulation layer between a rotor and a coupling, and hybrid drivetrain

Abstract

Torque transmission device (1) for a hybrid powertrain of a motor vehicle, wherein the torque transmission device (1) comprises: a friction clutch (4) having two mutually decoupleable rotating components (2, 3); and an electrical machine (5) operatively connected to one of the rotating components (2), wherein a rotor (6) of the electric machine (5) is mounted in a rotationally fixed manner on a first rotating component (2) of the friction clutch (4), and a thermal insulation layer (8) is arranged in a connection area (7) between the first rotating component (2) and the rotor (6), characterized by the fact that the thermal insulation layer (8) extends over the entire axial length of the rotor (6).

Description

[0001] The invention relates to a torque transmission device for a preferably hybrid drive train of a motor vehicle, such as a car, truck, bus or other commercial vehicle, according to the preamble of claim 1. Furthermore, the invention relates to a hybrid drive train / hybrid drive train of the motor vehicle with this torque transmission device.

[0002] Torque transmission devices are already well known in the art. For example, DE 11 2010 004 839 A5 discloses a torque transmission device that is inserted between a crankshaft of an internal combustion engine and a vehicle clutch or a transmission input shaft of a transmission. The torque transmission device has a separating clutch, a dual-mass flywheel, and an electric drive. It is also known from this document to arrange a clutch radially within a rotor of the electric machine.

[0003] However, it has been found that these designs known from the prior art have the disadvantage that, particularly when using friction clutches, especially dry friction clutches, temperatures can occur during operation of the drive train which can permanently damage the rotor connected to the respective rotating component of the friction clutch, in particular the permanent magnets contained therein.

[0004] From DE 199 27 261 A1 a torque transmission device according to the preamble of claim 1 is known. It is therefore an object of the present invention to eliminate the disadvantages known from the prior art and in particular to provide a torque transmission device in which the risk of thermal overload of the components of the electrical machine is further reduced.

[0005] This object is achieved by the measures specified in claim 1.

[0006] Further advantageous embodiments are the subject of the dependent claims.

[0007] A thermal insulation layer (also called thermal separation layer) is arranged in a connecting region between the first rotating component and the rotor.

[0008] By providing such an insulation layer, the amount of heat transferred from the friction clutch to the rotor during operation is significantly reduced. This reduces the thermal load on the rotor and further reduces the risk of rotor damage.

[0009] In this regard, it is particularly advantageous if the friction clutch is designed as a dry-running friction clutch. This makes the thermal decoupling provided by the insulation layer particularly effective.

[0010] Furthermore, it is advantageous if the rotor is designed as a rotor mounted radially outside the first rotating component. In this context, it is particularly advantageous if the rotor is mounted radially from the outside on a sleeve-shaped support section of the first rotating component.

[0011] In this context, it is particularly expedient if the insulation layer is arranged radially (as viewed with respect to a rotational axis of the friction clutch) between the rotor and a sleeve-shaped support section of the first rotating component. This allows the insulation layer to be integrated into the existing installation space of known designs in a particularly space-saving manner, and the corresponding designs can be adapted in just a few design steps. It is particularly advantageous if the separating layer is less than 0.1 mm thick or greater than 0.1 mm thick.

[0012] If the insulation layer is constructed / composed of several sub-areas, whereby the sub-areas are preferably implemented as layers, the insulation layer can be further optimized with regard to its insulating effect and strength.

[0013] Furthermore, the sub-regions are advantageously adjacent to one another in the axial direction, the radial direction, and / or the tangential direction / circumferential direction of the friction clutch, or are separated from one another in the axial direction, the radial direction, and / or the tangential direction of the friction clutch. This results in particularly suitable, different structures for the insulation layer.

[0014] It is also preferred if the at least two subregions are made of the same material. Alternatively or additionally, however, it is also possible for at least two further subregions or the same two subregions to be made of different materials.

[0015] In this context, particular reference is made to the following suitable materials for the insulation layer or, if the insulation layer is formed from several sub-regions, to the sub-regions themselves. In principle, it is preferable to form the insulation layer and / or the respective sub-region from a non-metallic material. Alternatively, it is also preferable to form the insulation layer and / or the respective sub-region from a metallic material. It is particularly clever to form the insulation layer and / or the respective sub-region from a plastic material. The plastic material is preferably implemented in a porous form. More preferably, the plastic material is an elastomer. It is also particularly clever to form the insulation layer and / or the respective sub-region from a ceramic material / ceramic, wherein the ceramics can have different bases (e.g., aluminum oxide, etc.).) but can also be in a fine or coarse ceramic composition. If the insulation layer and / or the respective partial area is formed from a metallic material, it is further preferred if this metallic material has comparatively poor thermal conductivity (in relation to deep-drawing steel or cast iron), with particular preference being given to steels with a high chromium content. Furthermore, it is expedient to use a metal foam as the metallic material, with the metal foam more preferably being a metal foam made from aluminum. Foams made from other materials can also be used. Glass or mineral wool is also preferably used for the insulation layer and / or the respective partial area. In further embodiments, organic materials, e.g. based on cellulose, cork, etc. are also used to form the insulation layer and / or the respective partial area.Concrete, preferably in porous form, is also used in other embodiments to form the insulation layer and / or the respective sub-area. Furthermore, a fluid material is also preferably used to form the insulation layer and / or the respective sub-area.

[0016] With regard to the fastening of the insulation layer, it is further advantageous if it is fastened in a form-fitting and / or force-fitting manner on the side of the rotor.

[0017] It is also advantageous if the insulation layer is attached to the first rotating component / the sleeve-shaped support section in a form-fitting and / or force-fitting manner. This makes it possible to bond the insulation layer to the components with particularly high fatigue strength, thus providing a layer that simultaneously serves to rigidly connect the rotor to the first rotating component.

[0018] With regard to the positive connection, it has proven particularly useful to form it as a toothed connection, for example, using a profile contour. A (direct) overmolding of the rotor and / or the first rotating component with the material of the insulation layer is also conceivable. With regard to the force-locking connection, a press fit is also particularly advantageous.

[0019] If a space filled with a thermal separation fluid (preferably in the form of a tubular sheath) is formed in the insulation layer, the insulation effect can be further improved.

[0020] The first rotating component is thus preferably designed as a clutch housing that is constructed in one or more parts. A second rotating component of the friction clutch preferably has at least one, and preferably several, clutch discs, for example two.

[0021] Furthermore, the invention relates to a hybrid drive train for a motor vehicle, with the torque transmission device according to the invention according to at least one of the previously described embodiments.

[0022] In other words, an effective thermal decoupling of an electric motor rotor from a clutch (friction clutch) is achieved in the form of a separating layer (insulating layer). The thermal decoupling between the rotor of the electric machine / electric motor and the separating clutch (friction clutch) is achieved by a thermally insulating separating layer between the rotor and the clutch.

[0023] The invention will now be explained in more detail below with reference to figures with reference to various embodiments.

[0024] They show: Fig. 1 is a longitudinal sectional view of a torque transmission device according to the invention according to a first embodiment, wherein the insulation layer arranged radially between a rotor of an electric machine and a rotating component of a friction clutch of the torque transmission device can be clearly seen, Fig. 2 a longitudinal sectional view of a torque transmission device according to the invention according to a second embodiment, wherein the insulation layer is designed as an overmolding applied to the rotor, and Fig. 3 a longitudinal sectional view of a torque transmission device according to the invention according to a third embodiment, wherein the insulation layer additionally forms an intermediate space filled with a separating fluid.

[0025] The figures are merely schematic in nature and serve exclusively to understand the invention. The same elements are provided with the same reference numerals. Furthermore, the different features of the various embodiments can be freely combined with one another.

[0026] In Fig. Figure 1 illustrates a torque transmission device 1 according to the invention according to a first exemplary embodiment. In this context, it should be noted that this torque transmission device 1 is fundamentally constructed and functions according to the torque transmission device described in DE 11 2010 004 839 A5. The basic structure of the torque transmission device of DE 11 2010 004 839 A5 is therefore considered to be integrated into the torque transmission device 1.

[0027] Accordingly, the torque transmission device 1 is also Fig. 1 is designed for use in a hybrid drive train of a motor vehicle. The torque transmission device 1 comprises, on the one hand, a clutch device, which in this case comprises a friction clutch 4. The friction clutch 4 is designed in the form of a dry-running friction clutch 4. In principle, however, it is also possible to equip the clutch device of the torque transmission device 1 with multiple clutches, preferably multiple friction clutches. Accordingly, in further embodiments, at least one further friction clutch, for example in the form of a double clutch, is provided in addition to the friction clutch 4.

[0028] An electric machine 5 is operatively connected to the clutch device / friction clutch 4. The electric machine 5 typically has a stator 13 that is arranged in a stationary manner / fixed to the housing. The stator 13 is fixedly received / mounted in a housing 23, which is, for example, fixedly connected to a transmission housing. A rotor 6 is arranged radially inside (as viewed with respect to a longitudinal axis 25 / axis of rotation of the friction clutch 4 / torque transmission device 1) of the stator 13. The rotor 6 is rotationally fixedly connected to a rotating component 2 of the friction clutch 4, here to a first rotating component 2). The first rotating component 2 forms a clutch housing of the friction clutch 4 and is designed in several parts or in one part.The torque transmission device 1 is thus a combination / system consisting of a clutch device and an electric machine 5 and is therefore also referred to as a hybrid module and is preferably implemented in a P2 arrangement.

[0029] The torque transmission device 1 is arranged, in use, between an output shaft 14 of an internal combustion engine and a transmission device 15, as viewed along the drive train. A dual-mass flywheel 16 is arranged between the output shaft 14 and the friction clutch 4, as viewed along the torque flow. An input part 17 in the form of a primary mass of the dual-mass flywheel 16 is rotationally fixedly connected to the output shaft 14 during operation, whereas an output part 18 in the form of a secondary mass of the dual-mass flywheel 16 is rotationally fixedly connected to a (second) rotating component 3 of the friction clutch 4.

[0030] The second rotating component 3 has a connecting shaft portion 19, a hub portion 20 mounted on the connecting shaft portion 19 in a rotationally fixed manner, and two clutch discs 21a and 21b. The clutch discs 21a and 21b can be coupled in a typical manner to the further (first) rotating component 2 of the friction clutch 4. In an engaged position of the friction clutch 4, the two clutch discs 21a and 21b are connected in a rotationally fixed manner to the first rotating component 2, whereas in a disengaged position of the friction clutch 4, the clutch discs 21a and 21b are freely rotatable relative to the first rotating component 2. The friction clutch 4 thus typically implements a separating clutch, which is designed as a multi-disk clutch. In principle, however, the design of the friction clutch 4 is not limited to such a design.In particular, multi-disk clutches or single-disk clutches are also conceivable for use with friction clutch 4. Furthermore, it is also possible to install additional friction clutches, such as a double clutch, in addition to friction clutch 4 in the further torque flow.

[0031] The first rotating component 2, in turn, has a sleeve-shaped support section 9, which extends radially outside the first clutch discs 21a and 21b and covers the clutch discs 21a and 21b in the axial direction from the radial outside. The rotor 6 is non-rotatably received / mounted radially outside the support section 9. The rotor 6 typically has several magnetic regions, such as permanent magnets, not shown in detail here. To support the support section 9, the first rotating component 2 additionally has a disc section 22, which is rotatably mounted relative to the housing 23.

[0032] According to the invention, a thermal insulation layer 8 / separating layer is arranged between the rotor 6 and the first rotating component 2, namely in a connecting region 7 between the rotor 6 and the first rotating component 2. This insulation layer 8 serves to shield the rotor 6 from heat generated during operation of the friction clutch 4. The insulation layer 8 is thus made of a material that ensures thermal insulation. The insulation layer 8 is formed over the entire axial length of the rotor 6. The insulation layer 8 is tubular (also referred to as a tubular casing). The insulation layer 8 thus surrounds the friction linings formed between the rotating components 2, 3, which interact with each other in a frictionally engaged manner and generate a large portion of the heat generated during operation.The insulation layer 8 is non-rotatably secured with its radial inner side to a radial outer side of the support section 9 / of the first rotating component 2, and is non-rotatably secured with a radial outer side to a radial inner side of the rotor 6. In particular, the insulation layer 8 is non-positively secured to the rotor 6 by means of a press fit and is non-positively secured to the first support section 9 by means of a press fit.

[0033] In these exemplary embodiments, the insulation layer 8 consists of a single layer / a single region / subregion, i.e., the insulation layer 8 is a single piece. In principle, however, in further embodiments, as described below with reference to the third exemplary embodiment, it is customary to form the insulation layer 8 in multiple parts, i.e., from several subregions 10a, 10b, for example, several layers. It is then possible to manufacture the individual subregions 10a, 10b from the same material or from different materials.

[0034] In relation to Fig. 2, which second embodiment largely corresponds to the first embodiment, it is also possible to additionally fasten the insulation layer 8 to the rotor 6 in a form-fitting manner. For this purpose, the insulation layer 8 is applied in the radial direction from the inside to the rotor 6 as an overmolding. For this purpose, the insulation layer 8 is preferably made of a plastic material. The insulation layer 8 designed as an overmolding forms two axial side wall regions 24, which are arranged spaced apart from one another in the axial direction and directly touch / rest against the rotor 6 in the axial direction. On the side of the carrier section 9, the insulation layer 8 is again fastened in a force-fitting manner, namely via a press fit, but alternatively also in a form-fitting and / or force-fitting manner.

[0035] Combined with Fig. 3 shows a third exemplary embodiment which also largely corresponds to the first exemplary embodiment. This third exemplary embodiment shows that it is also possible to design the insulation layer 8 in multiple layers / multi-part configurations. A first partial region 10a is implemented by an annular casing. This first partial region 10a forms an annular intermediate space 12 / cavity. A separating fluid 11 in the form of a separating liquid is arranged in this intermediate space 12. The separating fluid 11 forms a second partial region 10b of the insulation layer 8. This separating fluid 11 has a reinforcing effect on the insulating effect of the insulation layer 8. The second partial region 10b therefore differs from the first partial region 10a in terms of material. In addition, as already implemented in the second exemplary embodiment, the insulation layer 8 protrudes from the rotor 6 on both of its opposite sides.

[0036] In other words, the solution according to the invention essentially consists of a thermally insulating separating layer arranged between the rotor 6 and the clutch (friction clutch 4). In principle, the clutch 4 is arranged entirely or up to a certain axial extent within the rotor 6 of the electric motor 5. The clutch 4 has a clutch housing (first rotating component 2) which, as shown in Fig. 1, can be single-part or multi-part. The multi-part design can consist of a radial and / or axial subdivision. Fig. 1 also shows the separation point between rotor 6 and clutch 4 in general, to which the following solutions basically refer. Fig. The arrangement shown in Figure 1 shows a single K0 clutch / disconnect clutch (friction clutch 4) between a flywheel with centrifugal pendulum absorber (dual-mass flywheel 16) and a starting clutch. However, the proposed solution is also directly transferable to other arrangements, including systems with multiple clutches arranged at least partially within a rotor, e.g., a K0 clutch plus a double clutch.

[0037] The thermally insulating separating layer 8 ( Fig. 1) is suitable for insulating the heat generated in the (dry) clutch 4, which largely, but not exclusively, tends to be conducted from this clutch 4 towards the rotor 6 via material conduction. Various materials and structures are suitable for this purpose, which have a heat-insulating property as their primary or secondary function. Examples include: plastics, even in porous form; ceramics on various bases, e.g., aluminum oxide, even in fine or coarse ceramic form; elastomers; metallic materials, preferably with comparatively poor thermal conductivity (with regard to deep-drawing steel / casting), e.g., steels with a high chromium content; glass, even in the form of mineral wool; organic materials, e.g., cellulose-based, cork, etc.; foams, including metal-based ones, whose main function is for lightweight construction purposes or for the creation of large (reaction) surfaces; concrete, including in porous form; and fluids enclosed in a suitable tubular casing.

[0038] The separating layer 8 can be designed with different radial extensions, whereby a good compromise must be found between sufficient insulation and the smallest possible radial space requirement. Radial extensions from <0.1 mm up to several millimeters are possible, also depending on the type of enclosed clutch 4 (high or low energies) and the choice of the corresponding insulating medium / material. In particular, the separating layer 8 can also be formed from several layers / regions (subregions 10a, 10b) that are arranged axially, tangentially or radially, or in a combination thereof. The different layers can consist of the same or different materials. The axial and tangential fixation of the separating layer 8 on the single-part or multi-part clutch housing 2 or of the rotor 6 on the separating layer 8 can be achieved in different ways.Examples include a press fit or a positive connection such as broaching using a correspondingly designed profile contour. If the separating layer 8 consists of radially arranged layers (at least two), the aforementioned methods can be applied to securing the layers to one another.

[0039] Fig. 2 shows a further embodiment with a positive connection, as can be designed, for example, in a rotor 6 overmolded with a suitable plastic. Fig. Figure 3 shows a solution with a fluid 11 enclosed in a tubular enclosure as the main thermal separating agent. List of reference symbols 1 torque transmission device 2 first rotating component 3 second rotating component 4 Friction clutch 5 electric machine 6 Rotor 7 Connection area 8 Insulation layer 9 support section 10a first section 10b second section 11 Separating fluid 12 space 13 Stator 14 Output shaft 15 Gearbox 16 Dual-mass flywheel 17 Entrance part 18 Output part 19 Connecting shaft area 20 Hub area 21a first clutch disc 21b second clutch disc 22 disc section 23 housings 24 Side wall area 25 Longitudinal axis

Claims

[1] Torque transmission device (1) for a hybrid drive train of a motor vehicle, the torque transmission device (1) comprising: a friction clutch (4) having two decoupleable rotating components (2, 3); and an electrical machine (5) operatively connected to one of the rotating components (2), wherein a rotor (6) of the electric machine (5) is non-rotatably mounted on a first rotating component (2) of the friction clutch (4), and a thermal insulation layer (8) is arranged in a connecting region (7) between the first rotating component (2) and the rotor (6), characterized by , that the thermal insulation layer (8) is formed over an entire axial length of the rotor (6). [2] Torque transmission device (1) according to claim 1, characterized bythat the insulation layer (8) is arranged radially between the rotor (6) and a sleeve-shaped support section (9) of the first rotating component (2). [3] Torque transmission device (1) according to claim 1 or 2, characterized by that the insulation layer (8) is made up of several partial areas (10a, 10b). [4] Torque transmission device (1) according to claim 3, characterized by that the partial areas (10a, 10b) are connected to one another in the axial direction, radial direction or tangential direction of the friction clutch (4). [5] Torque transmission device (1) according to claim 3 or 4, characterized by that at least two sub-areas consist of the same material. [6] Torque transmission device (1) according to one of claims 3 to 5, characterized by that at least two sub-areas (10a, 10b) consist of different materials. [7] Torque transmission device (1) according to one of claims 1 to 6, characterized by that the insulation layer (8) is fixed in a form-fitting or force-fitting manner on the side of the rotor (6). [8] Torque transmission device (1) according to one of claims 1 to 7, characterized by that the insulation layer (8) is fixed in a form-fitting or force-fitting manner by the first rotating component (2). [9] Torque transmission device (1) according to one of claims 1 to 8, characterized by that an intermediate space (12) filled with a thermal separation fluid (11) is formed in the insulation layer (8). [10] Hybrid drive train for a motor vehicle, comprising a torque transmission device (1) according to at least one of claims 1 to 9.

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