Overload clutch with rotating shaft

Abstract

The present invention relates to an overload clutch (1) having a rotating shaft (2), comprising at least the following components: - a first shaft (3), - a second shaft (4), - a first friction element (5) torque-transmittingly connected to the first shaft (3), and - a second friction element (6) torque-transmittingly connected to the second shaft (4), wherein the first friction element (5) is in static friction contact with the second friction element (6) up to a predetermined slip torque, and the two shafts (3, 4) are torque-transmittingly connected to each other only by the friction elements (5, 6) in a predetermined limited manner according to the slip torque. The overload clutch (1) is particularly characterized in that the first shaft (3) and the second shaft (4) are arranged concentrically with respect to each other, and the friction elements (5, 6) are arranged radially between the first shaft (3) and the second shaft (4). The overload clutch proposed here is neutral in terms of installation space and can be used radially within an electric motor or shaft system.

Description

Technical Field

[0001] The present invention relates to an overload clutch having a rotating shaft, a shaft system having such an overload clutch with a rotating shaft for a drive train, an electric motor having such a shaft system with a rotating shaft for a drive train, a drive train having such an electric motor, and a motor vehicle having such a drive train.

Background Art

[0002] The present invention relates to an overload clutch (generally also referred to as a slip clutch), in which, below a predetermined torque (predetermined slip torque), the torque is transmitted from an input component, in particular an outer shaft or an inner shaft, to an output component, in particular an inner shaft or an outer shaft, by (static) friction, and above a predetermined slip torque, the (static) friction engagement is released or reduced to a transmissible torque having a magnitude below the predetermined slip torque.

[0003] In a motor vehicle having an internal combustion engine or a hybrid drive train, a starting clutch or a disengaging clutch is used as an overload clutch. The starting clutch is not provided for an electric axle module, which is referred to as an electric axle. As a result, the components of the electric axle are for overloads that can occur, for example, overloads resulting from torque peaks when the wheel contacts the road surface after the drive wheel has previously lost contact due to an uneven road surface. The overload clutch makes it possible to reduce the safety factor of the components, thereby potentially reducing costs and / or installation space.

[0004] A disadvantage of known overload clutches is that these overload clutches are usually configured with a large diameter like a conventional starting clutch. This means that such an overload clutch usually has to be inserted into the drive train using additional axial installation space. In particular, in a motor vehicle having an electric axle that has hitherto been configured without an overload clutch, such additional axial installation space is not available. [Overview of the project] [Problems that the invention aims to solve]

[0005] Therefore, an object of the present invention is to demonstrate a slip clutch that can be used particularly in the spatial conditions of electric axles, that is, one that requires as little additional axial mounting space as possible (and preferably no additional radial mounting space). [Means for solving the problem]

[0006] Based on this, an object of the present invention is to overcome, at least partially, the shortcomings known from the prior art. Features of the present invention arise from independent claims in which advantageous embodiments are shown in dependent claims. Features of the claims can be combined in any way that is technically reasonable, and features from the description and drawings in the following description, including additional embodiments of the present invention, can also be used for this purpose.

[0007] The present invention relates to an overload clutch having a rotating shaft, comprising at least the following components: - First shaft, - Second shaft, - A first friction element connected to the first shaft in a torque-transmitting manner, and -Having a second friction element that is torque-transmittingly connected to the second shaft, The first friction element is in static frictional contact with the second friction element up to a predetermined slip torque. The present invention relates to an overload clutch in which two shafts are torque-transmittingly connected to each other exclusively by friction elements in a predetermined limited manner according to the slip torque.

[0008] The overload clutch is characterized in that the first shaft and the second shaft are arranged concentrically with respect to each other, and the friction element is arranged radially between the first shaft and the second shaft.

[0009] In the following, unless otherwise specified, when axial, radial, or circumferential directions and their corresponding terms are used, the specified axis of rotation is being referred to. Unless otherwise specified, the ordinal numbers used in the preceding and following descriptions are used solely for the purpose of clear distinction and do not indicate the order or rank of the specified components. An ordinal number greater than 1 does not necessarily mean that there must be further such components.

[0010] An overload clutch (or slip clutch) is configured, for example, for conventional tasks, i.e., to prevent the transmission of torque peaks exceeding the configured maximum transmittable torque (around the rotation axis). For this purpose, torque transmission is (almost) completely cut off or limited to the slip torque or the configured maximum transmittable torque when it reaches or exceeds a predetermined slip torque corresponding to the configured maximum transmittable torque. It should be noted that deviations of up to ±15% around the configured slip torque may occur due to material pairing variations and / or over the service life; for example, the slip torque may be set 15% lower than the configured maximum transmittable torque.

[0011] During normal operation, the first and second shafts are torque-resistant and connected to each other with as little loss as possible (preferably almost no loss). However, the torque-resistant connection can be interrupted by the friction element at a predetermined slip torque, as described above. During normal operation, i.e., below the predetermined slip torque, the friction element is torque-resistant and connected to each other with a predetermined static friction force or predetermined static friction torque. When the predetermined slip torque is reached or exceeded, slip occurs beyond the static friction, and the two shafts rotate relative to each other.

[0012] Here, it is proposed that a first shaft and a second shaft are arranged concentrically with respect to each other. One shaft (e.g., the first) is an outer shaft configured as a hollow shaft, and the other shaft (in this case, e.g., the second, or alternatively, the first) is configured as an inner shaft extending at least partially into the outer shaft. This results in an axial overlap of the two shafts. Friction elements are radially positioned between the two shafts in the axial overlap. The first friction element is directly connected to the first shaft (i.e., assigned to the first shaft) so as to transmit torque (at least under normal conditions), and the second friction element is directly connected to the second shaft (i.e., assigned to the second shaft) so as to transmit torque (at least under normal conditions). Furthermore, the friction elements (under normal conditions) are in direct torque-transmitting contact with each other.

[0013] In a simple embodiment, at least one of the friction elements is connected to the assigned shaft in a torque-bearing manner (or for joint rotation) and is, for example, integrally formed or formed from a common base material (e.g., machined). Alternatively, both friction elements are connected in a torque-transmitting manner so that they are axially displaceable relative to the respective assigned shafts of the friction elements.

[0014] In one embodiment, the desired (i.e., predetermined) slip torque is set automatically during assembly by correctly performing the assembly, for example, by tightening screws to a predetermined torque. Alternatively or additionally, the predetermined slip torque is set in subsequent testing, preferably by slipping several times, to allow the friction elements and, optionally, the relatively rotatable shaft of one of the two shafts to break in. This ensures that slip occurs in the configured conditions during operation.

[0015] It should be noted that the friction torque required for a given slip torque is generated by the vertical force required to produce the necessary friction force in the axial, radial, or inclined direction relative to the axis of rotation [the friction force is equal to the product of the vertical force and the friction pair, i.e., the material pair and, where applicable, the (static) friction coefficient of the lubrication]. Furthermore, it should be noted that the vertical force itself arises from a preload force in the radial, axial, or inclined direction relative to the axis of rotation. At least one of the friction elements is expandable or compressible and / or (exclusively in simple embodiments) displaceable in the direction of the required vertical force.

[0016] In one embodiment, at least one of the friction elements is a sintered friction material, a metal, and / or an organic friction material.

[0017] In one embodiment, at least one of the friction materials for at least one of the friction elements is formed by a coating on a core material or a carrier material and / or in a multilayer structure.

[0018] Furthermore, in an advantageous embodiment of the overload clutch, it is proposed that each friction element comprises at least one wedge ring, which is axially clamped to one another such that, in accordance with a predetermined slip torque, a corresponding frictional force acting circumferentially is generated for torque transmission between concentric shafts, and preferably, at least one of the wedge rings has a slot that interrupts the entire circumference.

[0019] In this case, it is proposed that the friction elements be configured as wedge rings such that the axial preload force is converted into a radial vertical force or a vertical force inclined with respect to the axis of rotation, from which a circumferential friction force is generated to produce a desired friction torque (or a predetermined slip torque). In this case, the first friction element overlaps axially with at least one, preferably two, second friction elements, and / or the second friction element overlaps axially with one, preferably two, first friction elements.

[0020] In the overlapping portion of the two shafts, at least one first such annular friction element has a wedge-shaped inner contour, i.e., is conical over all or part of its rim, and is provided as a contact contour on the inner rim of the outer shaft (e.g., the first shaft). In the overlapping portion of the two shafts, at least one second such annular friction element has a conical outer contour corresponding to the conical inner contour of the outer shaft, and is provided as a contact contour on the outer periphery of the inner shaft (corresponding to the second shaft). The two friction elements are preloaded relative to each other by a preloading device acting axially on the two shafts. As a result, the conical inner contour is in (static) frictional contact with the corresponding conical outer contour, thereby enabling the transmission of torque between the outer and inner shafts up to a predetermined slip torque.

[0021] In advantageous embodiments, at least one of the friction elements comprises a plurality of wedge rings (stacked axially) or, preferably, a plurality of such friction elements are provided, each formed by a wedge ring. In one embodiment, a plurality of first friction elements and / or a plurality of second friction elements are arranged axially in a continuous manner in and on an outer shaft and / or on an inner shaft. In this embodiment, all (preferably a plurality of) wedge rings, with the exception of at least one wedge ring, are axially displaceable toward each other with respect to their assigned shafts, thereby allowing the wedge rings to press toward each other as a result of an axial preload force. For example, two or more wedge rings are provided in a corresponding number, for example, one more wedge ring on one shaft than on the other shaft, on each assigned shaft. For example, each axially inner wedge ring (in each structure) has a wedge surface that is axially inclined upward (i.e., rising) and a wedge surface that is axially inclined (i.e., descending), thereby giving these wedge rings a roof-like (contact) contour. As a result, in the cross-sectional view, the inner and outer contours of the axially stacked wedge rings result in a contact surface with a zigzag path (interrupted at the edge regions of the path).

[0022] In an advantageous embodiment, at least one of the friction elements configured as wedge rings is provided with a slot, whereby the wedge ring is considerably more flexible with respect to radial expansion or compression than a closed ring made of the same material and the same profile cross-section. In one embodiment, the slot is formed so as to be axially continuous. In an alternative embodiment, the slot is not axially continuous, i.e., it is configured as a blind recess. In an alternative embodiment, the slot is configured to be axially closed on both sides (i.e., as an opening having an axis oriented along the radial axis and / or a secant). In one embodiment, a plurality of such discontinuous or closed (preferably, similar) slots, and optionally additionally, continuous slots are provided. Alternatively, the material of the wedge ring is sufficiently flexible with respect to the desired expansion or compression to generate a predetermined slip torque.

[0023] In an advantageous embodiment of the overload clutch, a spring assembly for applying a preload to the friction element is provided radially inside the outer shaft of the two shafts, and it is further proposed that the spring assembly preferably comprises a plurality of disc springs.

[0024] Adjustability is achieved as a result of the extension of the preload distance due to the reduction of the spring stiffness by the spring assembly (a preloading device for generating the required axial preload force, radial preload force, or a preload force inclined with respect to the axis of rotation). This simplifies assembly and / or makes it possible to compensate for a larger tolerance range. In one embodiment, the preloading device is configured as a disc spring, preferably as a stack of disc springs (oriented identically to each other and / or mirror-symmetric).

[0025] In an advantageous embodiment of the overload clutch, a first wedge ring is held in a predetermined manner exclusively by static friction for torque transmission, It is further proposed that the second wedge ring is axially movable and torque-resistant connected to the second shaft by a tooth system.

[0026] The embodiment proposed here is particularly advantageous for wedge rings that expand or compress radially, because the wedge ring is connected to the assigned shaft by static friction without play, regardless of tolerance-related or different required specified slip torques. Alternatively, a tooth system with a corresponding play must be provided or more complex solutions such as circumferential anti-rotation must be used.

[0027] For the other wedge ring, it is configured such that there is no or negligible expansion or compression, and is torque-resistant connected to the assigned shaft by a corresponding tooth system, preferably a plug-in engagement, particularly preferably with a small amount of play or a slightly smaller dimensioned part (i.e., press fit), but is configured to be axially displaceable for assembly and, if necessary, in case of overload.

[0028] [[ID=ID=11]] In an advantageous configuration of the overload clutch, it is further proposed that the first shaft has a threaded receptacle for a preloading screw, and the preloading screw preferably has a threaded part outside the threaded receptacle for a counter element, particularly preferably for a clamping nut for a bearing ring, at the same time.

[0029] Here, it is proposed that the first shaft (preferably as an outer shaft) has a threaded receptacle, i.e., in one embodiment, the outer shaft has a female thread. The corresponding preloading screw can be screwed into or onto the threaded receptacle using its corresponding counter thread. This screw pair is preferably self-locking. Alternatively or additionally, fixing elements, such as retaining rings and / or counter elements, are provided. The counter element has, for example, a female thread that is preferably (particularly preferably for fixing) screwed into the aforementioned counter thread of the preloading screw (in the extended axial portion). Alternatively, additional threads and / or further steps on the preloading screw are provided for the counter element. Alternatively, different fixing concepts for the counter element, such as press bonding, weld bonding and / or adhesive bonding, are also possible.

[0030] In an advantageous embodiment, the counter element also constitutes a clamp nut for the bearing ring of a bearing (e.g., rolling) for the first shaft.

[0031] In an advantageous embodiment of the overload clutch, it is further proposed that an axially acting counter sleeve for receiving an axial preload on the friction element is fixed to the first shaft.

[0032] In this embodiment, a force clamp is simply formed on one of the shafts so as not to require a counter bearing for the preload force of the friction element. Easy assembly and / or adjustment for the friction element and / or the second shaft can be achieved by a counter sleeve (as an alternative to the corresponding shoulder on the first shaft for forming the force clamp). Alternatively or additionally, a suitable sliding pair between the counter sleeve and the second shaft for supporting the two shafts relative to each other can be achieved more easily or cost-effectively than when the second shaft is in direct contact with the first shaft (either completely or over a large area), for example, by the material selection of the counter sleeve and / or by tolerance specifications in a particular area.

[0033] In a further embodiment, a shaft system having a rotating shaft for a drive train, comprising at least the following components: - Torque input section, - Torque output section, and -Having an overload clutch according to the embodiment described above, A shaft system is proposed in which the torque input section is exclusively connected to the torque output section via an overload clutch for torque transmission.

[0034] In this case, a shaft system is proposed in which, under normal conditions, the torque input and torque output sections are torque-resistant to each other by (almost) a single shaft. Only under conditions other than normal, i.e., in the case of overload, is the torque transmission between the torque input and torque output sections interrupted or limited to the maximum torque (corresponding to a predetermined slip torque) or a lower torque that can be transmitted, according to the configuration. For this purpose, an overload clutch is used according to the embodiments described above. For example, the torque input section is torque-resistant to a first shaft, and the torque output section is connected to a second shaft (or vice versa), and is formed, for example, as a surface for press-fitting or as teeth for a plug-in engagement integrated with the shaft. Alternatively, the torque input section and / or torque output section are formed by structurally separate units and connected to the shaft torque-resistant or interruptible and / or to transmit torque.

[0035] It should be noted that the terms input and output do not rule out the possibility of torque being transmitted in opposite directions, i.e., from the torque output to the torque input. Preferably, the names torque input and torque output are synonymous with the direction of traction torque in, for example, the drivetrain of an automobile, i.e., the output of torque from the drive mechanism to the consumption part (e.g., the drive wheels).

[0036] In a further embodiment, an electric motor having a rotating shaft for a drive train, comprising at least the following components: -stator, - Rotor, and - Having an overload clutch according to the embodiment described above and / or a shaft system according to the embodiment described above, An electric motor is proposed in which the rotor is torque-resistantly connected to one of the shafts of the overload clutch, preferably the radially outer shaft, or to the torque input portion of the shaft system.

[0037] The electric motor (also referred to as an electric machine or electric drive machine) proposed herein includes the functions of torque generation and / or regeneration of externally applied torque, and overload protection by at least one overload clutch. This means that the electric motor and / or elements torque-transmittingly connected to the electric motor are reliably protected from torque peaks exceeding the maximum torque that can be transmitted as configured. Since no additional installation space is required, or only a negligible amount, or already present in the installation situation, this electric motor can be used (at least nearly) neutral in terms of installation space compared to an electric motor without an overload clutch. In one embodiment, different maximum transmittable torques are set by a plurality (preferably two) of overload clutches, for example, a higher slip torque is set relative to traction torque than to overrun torque.

[0038] In a further embodiment, a drive train is proposed, which comprises at least the following components: - At least one drive machine having an output shaft for outputting torque, - At least one consumption unit for receiving torque, and -Having a transmission gear system for transmitting torque between the drive machine and at least one consumption unit, The drive train comprises a shaft system according to the embodiment described above, and / or at least one of the drive machines is an electric motor according to the embodiment described above. A drivetrain is proposed in which the transmission of overload torque exceeding a predetermined slip torque between the output shaft and at least one consumption part is prevented by an overload clutch.

[0039] The drivetrain proposed herein comprises at least one drive machine, one of which is preferably an electric motor and / or (possibly further) drive machine, such as an internal combustion engine, a starter generator and / or (further) an electric drive machine, at least one of which forms a torque source for the torque flow in the main state. Furthermore, at least one consumption unit, such as the drive wheels of an automobile, is included, which forms a torque sink for the torque flow, at least in the main state. A transmission gear unit is connected between them, and the torque flow (preferably the entire wheel side) is guided through the transmission gear unit. In one embodiment, torque transmission is protected from transmission of torque peaks, preferably by a shaft system incorporated into the transmission gear unit and / or by electric motors, each having an overload clutch.

[0040] The drivetrain proposed herein includes an overload clutch that reliably limits the transmittable torque to slip torque or interrupts transmission when slip torque is reached. At the same time, the overload clutch can be used neutrally with respect to installation space and can continue to be used without modifying conventional or conventionally configured components. Compared to a drivetrain without an overload clutch, the components in the torque flow can be configured to be more elongated and / or more cost-effective.

[0041] In a further manner, the automobile is It comprises at least one drive wheel and a drive train according to the embodiment described above, To drive an automobile, torque can be output from at least one drive mechanism of the drivetrain to at least one drive wheel. An automobile is proposed in which the transmission of overload torque exceeding a predetermined slip torque between the output shaft and at least one drive wheel is prevented by an overload clutch.

[0042] The automobile is, for example, a passenger car, a truck, or an electric two-wheeled vehicle. The automobile has a drivetrain according to the embodiments described above. Torque that can be output from at least one drive machine is output to at least one drive wheel (consumer) via a transmission gear system. The transmission gear system referred to herein is preferably a shiftable transmission gear system. In one embodiment, the transmission gear system further comprises, for example, a differential. In one embodiment, torque transmission is protected from transmission of torque peaks, preferably by a shaft system incorporated into the transmission gear system and / or by electric motors, each having an overload clutch.

[0043] The automobile proposed herein features a drivetrain with an overload clutch that reliably limits the transmittable torque to slip torque or interrupts transmission when slip torque is reached. At the same time, the overload clutch can be used neutrally with respect to installation space and can continue to be used without modifying conventional or conventionally configured components. Compared to a drivetrain without an overload clutch, the components in the torque flow can be configured to be more elongated and / or more cost-effective.

[0044] Further advantageous embodiments of the overload clutch (or slip clutch) are listed below: 1. A slip clutch having an outer shaft configured as a hollow shaft and an inner shaft extending at least partially concentrically within the outer shaft, At least one first annular friction element having a conical inner contour is provided on the inner periphery of the outer shaft, At least one second annular friction element having a conical outer contour is provided on the outer periphery of the inner shaft, Two friction elements are preloaded relative to each other by a preloading device acting axially on the shaft (on the outer and inner sides, concentric with each other). This slip clutch allows the conical inner contour to frictionally contact the conical outer contour, thereby transmitting torque between the outer and inner shafts.

[0045] 2. The first friction element is preferably connected to the outer shaft by a plug-in engagement portion so as to rotate together with it, and / or The slip clutch according to Embodiment 1, wherein a second friction element is preferably connected to an inner shaft so as to rotate together with it by a plug-in engagement portion.

[0046] 3. The slip clutch according to Embodiment 1 or 2, wherein the conical inner contour and the conical outer contour are configured to alternately rise and fall such that, when viewed in the axial direction, the cross-sectional view of the contact surface formed by the inner contour and the outer contour each has a substantially zigzag path.

[0047] 4. A slip clutch according to any one of embodiments 1 to 3, wherein a plurality of first friction elements and / or a plurality of second friction elements are arranged axially in a continuous manner within and / or on an inner shaft.

[0048] 5. The first friction element overlaps the two second friction elements in the axial direction, and / or The slip clutch according to Embodiment 4, wherein the second friction element overlaps the two first friction elements in the axial direction.

[0049] 6. A slip clutch according to any one of embodiments 1 to 5, wherein the preloading device is configured as a disc spring, preferably as a stack of disc springs.

[0050] 7. Having a rotor shaft configured as the outer shaft or inner shaft of the slip clutch described in any one of embodiments 1 to 6, or An electric machine, particularly an electric motor, in which the rotor shaft of the electric machine is connected to rotate together with the outer or inner shaft of a slip clutch described in any one of embodiments 1 to 6.

[0051] 8. An electric axle module or hybrid module for an automobile having the electromechanism described in Embodiment 7.

[0052] The invention described above will be described in detail below with reference to the associated drawings illustrating preferred embodiments and to the relevant technical background. The invention is by no means limited by purely schematic drawings, however, it should be noted that the drawings are not dimensionally accurate and are not suitable for defining proportions. [Brief explanation of the drawing]

[0053] [Figure 1] This is a cross-sectional view showing details of a drive train having an electric motor on an electric axle. [Figure 2] This is a partial cross-sectional view of a shaft system having an overload clutch. [Figure 3] This diagram shows a drive train having a transmission gear system and a power consumption unit. [Figure 4] This is a plan view of an automobile with a drivetrain. [Modes for carrying out the invention]

[0054] Figure 1 is a cross-sectional view detailing a drive train 17 having an electric motor 20 on an electric axle for outputting torque around a rotating shaft 2, showing the electric motor 20, a transmission gear unit 27, and a conventional rotor shaft 31 as an output shaft 24. The electric motor 20 is configured in this case (purely optional) as a conventional rotor shaft consisting of a hollow shaft 31 torque-resistantly connected to a rotor 22 (e.g., a pressed laminated core). This connection between the rotor 22 and the rotor shaft 31 forms a torque input section 18 (in a state that outputs traction torque). The rotor 22 can be electromagnetically driven by a rotatably fixed stator 21. The rotor shaft 31 is mounted by a (first) bearing unit 35, the inner bearing ring 14 of which is shown on the left of the figure and is described in more detail in the following figure, Figure 2.

[0055] The rotor shaft 31 is torque-bearingly connected to the transmission gear unit 27, in this case, for example, a planetary transmission (as shown here, purely optionally, axially adjacent to the electric motor 20) and a differential gear (spur gear) 43 (as shown on the right), on the right side of the figure. The left (torque output section 19) of the two drive shafts 32 shown here is guided through the (hollow) rotor shaft 31 and is separately mounted to the gear unit housing 34 by a (second) bearing unit 36. The drive shaft 33, mounted by a separate third bearing unit 37 (torque output section 19), branches to the right, as shown on the right. In this case, (purely optionally) on the transmission gear unit side, the bearings of the second bearing unit 36 ​​and the third bearing unit 37 are also configured to simultaneously support the differential gear 43.

[0056] The following figure, Figure 2, shows a shaft system 16 that can be used as a replacement for the rotor shaft 31. Note that the drive shafts 32 and 33 are not replaced, but the corresponding left drive shaft 32, which serves as the torque output section 19, is guided (in principle, purely by choice) through a hollow second shaft 4 (see figure).

[0057] Figure 2 shows a shaft system 16 having an overload clutch 1 in a partial quarter cross-section with respect to its axis of rotation 2. This shows a first shaft 3 (referred to as the outer shaft) configured as a hollow shaft and a second shaft 4 (referred to as the inner shaft) (similarly, purely optionally hollow) extending at least partially concentrically into the first (outer) shaft 3. At least one first annular friction element 5 having a conical inner contour 29 is provided on the inner rim of the first shaft 3. At least one second annular friction element 6 having a conical outer contour 30 is provided on the outer periphery of the second shaft 4. The two friction elements 5 and 6 are preloaded relative to each other by a preloading device 38 acting axially on the two shafts 3 and 4, so that the conical inner contour 29 is in (static) frictional contact (i.e., surface contact) with the conical outer contour 30, thereby allowing torque to be transmitted between the first shaft 3 and the second shaft 4 in such a way that torque is limited to a maximum torque.

[0058] In this case, the preloading device 38 includes a preloading screw 11 and a spring assembly 8 comprising a plurality of disc springs (arranged alternately in a mirror image purely at will) (referred to herein as a stack of disc springs). The preloading screw 11 is configured to adjust or preload the spring assembly 8 by interaction between a threaded receptacle 10, which is configured as a female thread on the first shaft 3, and a counter screw 39 in the region of the threaded portion 12 of the preloading screw 11. It should be noted that other preloading devices 38, such as a coil spring and / or a hydraulic preloading device 38, may be used and / or may be used without the spring assembly 8.

[0059] In this embodiment, the counter element 13 is screwed into the corresponding female thread on the counter thread 39 (here, purely optional, continuous) of the preloading screw 11, for example, to cause or fix the preloading screw 11. In this case, for example, the (inner) bearing ring 14 of the (first) bearing device 35 (see Figure 1) is kept in a state where it is axially preloaded by the counter element 13. Note that if the corresponding outer bearing ring has a movable bearing seat, or if the seat of the fixed bearing seat is axially adjustable, double-fitting collision will not occur.

[0060] In the illustrated embodiment, the first friction element 5 is torque-transmittingly connected to the first shaft 3 (outer shaft in this specification) exclusively by static friction. In this case, a plurality of first friction elements 5 or first wedge rings 5 ​​are arranged axially continuous (i.e., axially stacked) and radially inward of the first shaft 3. The first wedge rings 5 ​​are configured to have (purely optional) axially continuous slots 7, thereby being flexible against radial expansion caused by axial preloading by the preloading device 38.

[0061] In the illustrated embodiment, the second friction element 6 is torque-transmittingly connected to the second shaft 4 (inner shaft in this specification) by a tooth system 9 (preferably a plug-in mesh). In this case, a plurality of second friction elements 6 or second wedge rings 6 (more than 6 second wedge rings in this specification), corresponding to the number of first wedge rings 5, are arranged axially continuous (i.e., axially stacked) on the radially outward side of the second shaft 4. The second wedge rings 6 are configured to be closed circumferentially (purely optional), thereby being rigid with respect to diameter against radial compression as a result of axial preloading by the preloading device 38. Thus, the (inner) second wedge rings 6 are (almost) immutable on the (inner) second shaft 4 and slightly displaceable in the axial direction.

[0062] The conical inner contour 29 and conical outer contour 30 of a pair of wedge rings 5 ​​and 6 are configured to alternately rise and fall in the axial direction, so that the cross-sectional view of the contact surfaces formed by the inner contour 29 and outer contour 30 has a zigzag path. The first wedge ring 5 overlaps axially with two second wedge rings 6. Similarly, the (axially inner) second wedge rings 6 overlap axially with two first wedge rings 5. The two axially outer second wedge rings 6 overlap (axially inner) with a single second wedge ring 6 and, axially outer, form axial contact for transmitting the axial preload force of a preloading device 38 (shown on the left) or a counter sleeve 15 (shown on the right), respectively. The counter sleeve 15 is torque-resistantly connected to the first shaft 3, for example, by pressing and / or welding. The second shaft 4 is mounted (slidably) within the counter sleeve 15 and supported so as to be rotatable relative to the first shaft 3 (and the counter sleeve 15) when slip torque is reached.

[0063] Furthermore, between each pair of adjacent wedge rings 5, 6, intermediate rings (which are purely selective and not shown here) are provided, and these intermediate rings, like the wedge rings 5, 6, are formed integrally, from multiple parts, and / or elastically.

[0064] As already mentioned above, the outer shaft (here the first shaft 3) or inner shaft (here the second shaft 4) of the overload clutch 1 is configured as the rotor shaft 31 of the electric motor 20 and / or connected to the rotor shaft 31 of the electric motor 20 as a separate component in a torque-resistant manner. The electric motor 20 is, for example, part of the electric axle module (also known as electric axle) or hybrid module of the drivetrain 17 of an automobile 28. In this case, the inner shaft (here the second shaft 4) is also configured as a hollow shaft, thereby allowing the drive shaft 32 (see Figure 1) to pass through.

[0065] Figure 3 shows a drive train 17 having a shaft system 16 (see Figure 2), an electric drive machine 23, a transmission gear unit 27, a (bevel gear) differential 43, and a consumption unit. The output shaft 24 of the drive machine 23, i.e., the rotor shaft 31 in this case, is formed here by the shaft system 16 (compared to the rotor shaft 31 without an overload clutch 1, which is used neutrally with respect to the installation space). The electric motor 20 and the shaft system 16 are shown in cross-sectional view. The drive machine 23 is torque-tolerantly connected to the output shaft 24 of the shaft system 16 by the transmission gear unit 27 so as to be limited to a predetermined slip torque. The transmission gear unit 27 includes a differential 43 (here, purely optionally, a bevel gear differential) in addition to transmission stages (e.g., purely optionally, a helical spur gear unit). By the differential 43, the torque is divided as needed between two drive shafts 32, 33, each having a drive wheel 25, 26.

[0066] Figure 4 schematically shows a vehicle 28 having a drivetrain 17 in a plan view, where, in a transverse-forward configuration, an electric motor 20 as a drive machine 23 having an output shaft 24 is positioned in front of the driver's seat 40 of the vehicle 28, along the motor shaft 42, crossing the longitudinal axis 41. The drivetrain 17 is configured to propel the vehicle 28 by driving the left drive wheel 25 and the right drive wheel 26 (here optionally the front axle of the vehicle 28) with torque output from the electric motor 20 via a transmission gear unit 27. Torque transmission from the electric motor 20 can be passively interrupted by an overload clutch 1, which is configured, for example, as shown in Figure 2 and incorporated into the electric motor 20 and / or transmission gear unit 27, thereby protecting at least the electric motor 20, or conversely, the rest of the drivetrain 17, from overload (e.g., torque shock).

[0067] The overload clutch proposed here is designed to be neutral with respect to the installation space, allowing for use radially inside an electric motor or shaft system. [Explanation of symbols]

[0068] 1. Overload clutch 2 rotation axes 3. First shaft 4. Second shaft 5. First friction element 6. The second friction element 7 slots 8 Spring Assembly 9 Tooth System 10 threaded receptacles 11 Preloaded screw 12 threaded part 13 counter elements 14 Bearing rings 15 counter sleeves 16 Shaft System 17. Drivetrain 18 Torque input section 19 Torque output section 20 Electric motors 21 Stator 22 rotors 23 Drive mechanism 24 output shafts 25 Left drive wheel 26 Right drive wheel 27 Transmission Gear System 28 Automobiles 29 Inner contour 30 Outer contour 31 Conventional rotor shaft 32 Left drive wheel 33 Right drive wheel 34 Gear mechanism housing 35 First bearing device 36. Second bearing device 37 Third bearing device 38 Preload device 39 Counter Screw 40 Driver's seat 41 Longitudinal axis 42 Motor shaft 43 Differential gear

Claims

1. An overload clutch (1) having a rotating shaft (2), comprising at least the following components: - First shaft (3), - Second shaft (4), - The first friction element (5) is connected to the first shaft (3) in a torque-transmitting manner, and - The second friction element (6) is connected to the second shaft (4) in a torque-transmitting manner, The first friction element (5) is in static frictional contact with the second friction element (6) up to a predetermined slip torque. Two shafts (3, 4) are torque-transmittingly connected to each other by the friction elements (5, 6) in a predetermined limited manner according to the slip torque. An overload clutch (1) characterized in that the first shaft (3) and the second shaft (4) are arranged concentrically with respect to each other, and the friction elements (5, 6) are arranged radially between the first shaft (3) and the second shaft (4).

2. Each of the friction elements (5, 6) includes at least one wedge ring (5, 6), and the wedge rings (5, 6) are axially clamped against each other according to the predetermined slip torque such that a corresponding frictional force acting circumferentially is generated for torque transmission between the concentric shafts (3, 4). Preferably, at least one of the wedge rings (5) has a slot (7) that interrupts the entire circumference, as described in claim 1.

3. A spring assembly (8) for applying a preload to the friction elements (5, 6) is provided radially inward of the outer shaft (3) of the two shafts (3, 4). The spring assembly (8) preferably includes a plurality of disc springs. The overload clutch (1) according to claim 1 or 2.

4. The first wedge ring (5) is held exclusively by static friction in a predetermined manner to transmit torque, The overload clutch (1) according to any one of claims 1 to 3, wherein a second wedge ring (6) is connected to the second shaft (4) by a tooth system (9) in an axially movable and torque-resistant manner.

5. The first shaft (3) has a threaded receptacle (10) for a preload screw (11), The overload clutch (1) according to any one of claims 1 to 4, wherein the preload screw (11) preferably has a threaded portion (12) on the outside of the threaded receptacle (10) for a clamp nut for a counter element (13), and particularly preferably for a bearing ring (14).

6. An overload clutch (1) according to any one of claims 1 to 5, wherein an axially acting counter sleeve (15) for receiving the axial preload of the friction elements (5, 6) is fixed within the first shaft (3).

7. A shaft system (16) having a rotating shaft (2) for a drive train (17), comprising at least the following components: - Torque input section (18), - Torque output unit (19), and - Having an overload clutch (1) according to any one of claims 1 to 6, A shaft system (16) in which the torque input section (18) is exclusively connected to the torque output section (19) by the overload clutch (1) in a torque-transmitting manner.

8. An electric motor (20) having a rotating shaft (2) for a drive train (17), comprising at least the following components: - Stator (21), - Rotor (22), - comprising an overload clutch (1) according to any one of claims 1 to 6 and / or a shaft system (16) according to claim 7, An electric motor (20) in which the rotor (22) is torque-resistantly connected to one of the shafts (3, 4) of the overload clutch (1), preferably the radially outer shaft (3), or to the torque input section (18) of the shaft system (16).

9. The drive train (17) comprises at least the following components: - At least one drive machine (23) having an output shaft (24) for outputting torque, - At least one consumption unit (25, 26) for receiving torque, and - The drive machine (23) and the at least one consumption unit (25, 26) have a transmission gear device (27) for transmitting torque between them. The drive train (17) comprises the shaft system (16) described in claim 7, and / or at least one of the drive machines (23) is an electric motor (20) described in claim 8. A drive train (17) in which the transmission of an overload torque exceeding the predetermined slip torque between the output shaft (24) and the at least one consumption unit (25, 26) is prevented by the overload clutch (1).

10. An automobile (28) having at least one drive wheel (25, 26) and a drive train (17) according to claim 9, Torque can be output from at least one drive machine (23) of the drive train (17) to at least one drive wheel (25, 26) for propulsion of the automobile (28). An automobile (28) in which the transmission of an overload torque exceeding the predetermined slip torque between the output shaft (24) and the at least one drive wheel (25, 26) is prevented by the overload clutch (1).

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