Switching element for frictional and form-fit transmission of torque

Abstract

Switching element (1) with a rotation axis (5) extending along an axial direction (4), comprising a first shaft (6), a second shaft (7) arranged coaxially to the first shaft (6), and a switching device (8) for switching the shafts (6, 7); wherein the switching device (8) has an actuator (9) for switching the connection, wherein, for connecting the shafts (6, 7), a friction-fit first connection (10) of the shafts (6, 7) can first be established by the actuator (9), and thereby a subsequent positive-locking second connection (11) of the shafts (6, 7) is effected; wherein the second shaft (7) is arranged in a fixed position relative to the first shaft (6) with respect to the axial direction (4), characterized in that the switching device (8) at least • an intermediate element (18) connectable to the first shaft (6) only via the first connection (10), comprising a first ramp (28) of a ball ramp system (17) arranged in a fixed position relative to the first shaft (6) with respect to the axial direction (4); and • a second ramp section (47) which is displaceable relative to the intermediate element (18) along the axial direction (4) and which comprises a second ramp (29) which interacts with the first ramp (28) as a ball ramp system (17); wherein the second ramp section (47) and the intermediate element (18) are rotatably connected to each other via the ball ramp system (17) about a limited second angular range; wherein the second ramp section (47) is displaceable via the ball ramp system (17) along the axial direction (4) when the intermediate element (18) is rotated relative to the second ramp section (47), and as a result of this displacement the second connection (11) between the first shaft (6) and the second shaft (7) can be established.

Description

[0001] The present invention relates to a switching element, in particular for a drive train of a motor vehicle, which allows a frictional and positive transmission of torques.

[0002] The shift element is designed specifically for an electrically driven axle of a motor vehicle. The shift element can be used to engage and disengage the wheel driven by an electric motor. The shift element is designed specifically for all-wheel drive applications and is intended to enable rapid engagement and disengagement, especially for high torques.

[0003] DE 41 35 534 A1 discloses a switching element that can be read off from the preamble of claim 1. US 2 584 116 A discloses an electromagnetic switching element with a spring-loaded, rotatable armature plate. JP H05-272 558 A discloses another electromagnetic switching element.

[0004] Furthermore, the older, unpublished DE 10 2021 104 355 A1 discloses a shifting element, in particular for a drive train of a motor vehicle, with a rotational axis extending along an axial direction, comprising a first shaft, a second shaft arranged coaxially to the first shaft, and a shifting device for switchably connecting the shafts. The shifting device has an actuator for switching the connection, wherein, to connect the shafts, the actuator can first establish a frictionally engaged first connection between the shafts, followed by a subsequent positively engaged second connection between the shafts. To establish the positively engaged second connection, the second shaft is moved along the axial direction.

[0005] Proceeding from this, the present invention is based on the object of at least partially overcoming the problems known from the prior art and, in particular, of providing a switching element by means of which a secure connection between two shafts can be established for high torques, but wherein the second shaft is not moved along the axial direction.

[0006] This object is achieved by the features of independent claim 1. Further advantageous embodiments of the invention are specified in the dependent claims. The features listed individually in the dependent claims can be combined with one another in a technologically expedient manner and can define further embodiments of the invention. Furthermore, the features specified in the claims are further specified and explained in the description, with further preferred embodiments of the invention being presented.

[0007] A switching element is proposed, in particular for a drive train of a motor vehicle, with an axis of rotation extending along an axial direction, comprising a first shaft, a second shaft arranged coaxially to the first shaft, and a switching device for switchably connecting the shafts. The switching device has an actuator for switching the connection, wherein, in order to connect the shafts, a frictionally engaged first connection of the shafts can first be established by the actuator, which subsequently creates a positively engaged second connection of the shafts, wherein the second shaft is arranged stationary relative to the first shaft with respect to the axial direction.

[0008] The shafts are arranged coaxially to one another and therefore share a common axis of rotation. The switching device enables the switchable connection of the shafts to one another.

[0009] The switching device comprises an actuator, the actuation of which enables the connection between the shafts to be established in a switchable manner.

[0010] The shafts are connected to each other successively. First, the first connection is established after the actuator is activated. As a result of the first connection, the different speeds of the shafts are synchronized (i.e., aligned). The second connection is only initialized after the first connection has been established.

[0011] In particular, the second connection is established automatically, i.e., without additional actuation of the actuator. If necessary, the second connection is established by actuating the actuator, e.g., by applying a higher current to the actuator than the current required to establish the first connection. However, the second connection is only established if the actuator was actuated to establish the first connection or is still actuated.

[0012] When the actuator is no longer operated, the first connection and thus also the second connection are released.

[0013] In particular, the switching device is designed in such a way that the second connection is only established after complete or almost complete synchronization of the speeds of the shafts.

[0014] In the present case, a relative movement of the second shaft with respect to the first shaft along the axial direction is not required to form the second connection. The displacement of the second shaft disclosed in DE 10 2021 104 355.7 is achieved in the present case by a displacement of a separate (second) ramp part. In this context, "stationary" means, i.e., with reference to the arrangement of the first shaft and the second shaft, that the shafts can certainly be arranged so that they can move relative to one another (e.g., to compensate for tolerances and / or to provide play between these shafts), although this mobility has no influence on the establishment or release of the second connection (or the other connections created in the switching element).

[0015] In particular, the actuator is a magnetic coupling which has at least one magnet, a rotary transformer connected in a rotationally fixed manner to the first shaft, and a stator connected (or connectable) to the second shaft (via the intermediate element mentioned below), wherein by energizing the magnet the stator can be displaced along the axial direction to form the first connection with the rotary transformer.

[0016] In particular, the magnetic coupling comprises a plurality of magnets arranged side by side along a circumferential direction. Energizing the (electro)magnets can generate a magnetic field that moves the stator toward the rotary transformer. The rotary transformer transfers the magnetic field from the stationary coil to the rotating system.

[0017] In particular, the rotary transformer is arranged along the axial direction between the at least one magnet and the stator.

[0018] The rotary joint is connected to the first shaft in a rotationally fixed manner. The stator is connected to the second shaft (via additional components), so that the first shaft can be connected to the second shaft via the frictionally engaged first connection between the rotary joint and the stator.

[0019] The at least one magnet is in particular connected in a rotationally fixed manner to a housing of the switching device, wherein the first shaft is arranged rotatably relative to the housing, e.g. via a first bearing.

[0020] A contact force between the rotary transformer and the stator can be controlled via a current control of the actuator.

[0021] In particular, the shafts are connected via a first working memory, which allows a relative rotation of the components connected to one another via the working memory by a limited first angular range and thereby stores the work required for the rotation.

[0022] In particular, the first working storage device comprises at least one spring, e.g., a bow spring, which is deformable at least relative to a circumferential direction for storing work.

[0023] The first angular range over which the components connected to one another via the main memory can be rotated relative to one another comprises, in particular, between 20 and 180 degrees, in particular, at most 120 degrees, preferably at most 90 degrees. In particular, the first angular range comprises at least 45 degrees, preferably at least 60 degrees.

[0024] In particular, the shafts can be connected or are connected to one another via further components (e.g. via the rotary transformer, the stator, an intermediate element, a second ramp part, a ball ramp system formed by the intermediate element and the second ramp part, etc.), so that the shafts (even when the first connection has been established) can be rotated relative to one another over a larger angular range than the first angular range.

[0025] In particular, the first memory allows the second connection to be established only after the shaft speeds have been synchronized.

[0026] In particular, the switching device comprises an intermediate element that can be connected to the first shaft only via the first connection, which comprises (on a first ramp part arranged with the intermediate element or formed by the intermediate element) a first ramp of a ball ramp system that is arranged in a fixed position relative to the first shaft with respect to the axial direction. In particular, the switching device comprises a second ramp part that is displaceable relative to the intermediate element along the axial direction and comprises a second ramp that interacts with the first ramp as a ball ramp system.

[0027] The second ramp part and the intermediate element (with the first ramp part) are connected to each other via the ball ramp system so that they can rotate relative to each other within a limited second angular range. Upon relative rotation of the intermediate element relative to the second ramp part, the second ramp part can be displaced along the axial direction via the ball ramp system, and as a result of this displacement, the second connection between the first shaft and the second shaft can be established.

[0028] The second angular range over which the intermediate element can be rotated relative to the second ramp part comprises, in particular, between 20 and 160 degrees, in particular at most 120 degrees, preferably at most 90 degrees. In particular, the second angular range comprises at least 45 degrees, preferably at least 60 degrees.

[0029] In particular, the ball ramp system is designed such that, starting from an unshifted arrangement of the second ramp part, the intermediate element can be rotated in both directions of rotation relative to the second ramp part (or the second shaft), so that upon relative rotation in both directions of rotation, the second ramp part is displaced in the axial direction.

[0030] The intermediate element is connected to the stator in particular via the first working memory, so that the intermediate element can be rotated relative to the stator by the limited first angular range.

[0031] The intermediate element has, in particular, a plurality of first ramps, and the second ramp part has a corresponding plurality of second ramps, in particular three ramps each with a total of three balls, which form the ball ramp system. A (second) ball is arranged between each of the ramps.

[0032] When the first connection is established, an adjustable torque is transmitted between the first shaft and the switching device. This torque causes the intermediate element to rotate relative to the second ramp section, so that the second ramp section is displaced along the axial direction via the ball ramp system.

[0033] In particular, the switching device comprises a second working memory that stores the work required to displace the second ramp part along the axial direction. Only after the second ramp part has been displaced along the axial direction can the second connection between the first shaft and the second shaft be established.

[0034] In particular, the second ramp part can be connected to the first shaft via a frictionally engaged third connection as a result of the displacement of the second ramp part along the axial direction. Furthermore, the second ramp part can be connected to the second shaft via the frictionally engaged third connection as a result of the displacement of the second ramp part along the axial direction.

[0035] In particular, the second shaft is connected to a plate (friction disc) via leaf springs. The plate forms, in particular, the third connection to the second ramp section. The plate forms, in particular, the third connection to the first shaft (e.g., via the cage element, see below). The leaf springs support torque relative to the circumferential direction.

[0036] In particular, the second ramp part is connected to the plate (friction disc) and / or the second shaft via leaf springs. The leaf springs support torque in the circumferential direction.

[0037] In particular, the second working storage device comprises a spring, in particular a disc spring, which is deformable at least with respect to the axial direction for storing work.

[0038] The disc spring can, for example, be arranged along the axial direction between the second shaft and the lamella.

[0039] As a result of the displacement of the second ramp section along the axial direction, the lamella can be displaced toward the second shaft, thereby gradually deforming the disc spring. The third connection can thus be formed between the second ramp section and the first shaft (via the cage element) or between the first shaft (or the cage element) and the second shaft.

[0040] In particular, the spring of the second working memory has a spring characteristic with at least one local minimum, wherein the switching device is arranged such that the second connection is made only in a region of the local minimum.

[0041] In particular, the spring has a spring characteristic with at least one local maximum. Starting with an unactuated switching element, the spring is successively deformed upon actuation of the switching element by the displacement of the second ramp section along the axial direction, so that the local maximum is initially exceeded and the spring force gradually decreases with further deformation (down to) the local minimum. The presence of a maximum enables two-stage actuation by the actuator. For example, the first connection can be established by a first current supply to the actuator, and the second connection can be established by a higher second current supply to the actuator.

[0042] In particular, the second connection occurs in a state of the switching device that lies between the local maximum and the local minimum. Preferably, this occurs in a range that, starting from the local maximum, lies close to or immediately before the local minimum. However, the range can also extend beyond the local minimum.

[0043] Between the local maximum and the local minimum, the spring is deformable, in particular, by a certain distance. The region in which the second connection can be established or is established comprises, in particular, a distance that is at most 20% of the distance between the maximum and minimum.

[0044] In particular, the spring is relaxed, i.e., force-free, when the switching element or switching device is not actuated. In particular, the spring is only increasingly tensioned when the actuator is actuated and during the successive establishment of the first connection.

[0045] In particular, the second connection is made by a plurality of first balls, each first ball being arranged, on the one hand, in each state of the switching device in a first ball track of the first shaft running along the axial direction and, on the other hand, and only in the state of the switching device with the second connection established, in a second ball track of the second shaft running along the axial direction and, in another state, outside the second ball track in a cylindrical section of the second shaft.

[0046] The cylindrical portion is designed to be circumferential in the circumferential direction and extends along the axial direction, so that when the first balls are arranged in the cylindrical portion, the second shaft is freely rotatable relative to the first balls arranged in the first ball tracks.

[0047] If the first balls are arranged in the cylindrical section, the second shaft can rotate freely relative to the first shaft, possibly only limited by the frictional first connection and / or the frictional third connection.

[0048] As a result of the displacement of the second ramp part along the axial direction, the first balls can be transferred from the cylindrical section into the second ball tracks, so that the second connection which is positively locked relative to the circumferential direction is then realized.

[0049] In particular, a cage element is arranged between the first shaft and the second shaft. This cage element comprises at least one cylindrical sleeve portion extending along the axial direction between the first shaft and the second shaft and having a plurality of windows. One of the first balls is arranged in each window.

[0050] In particular, the cage element comprises a flange portion extending outwardly from the sleeve portion in a radial direction. The flange portion is arranged along the axial direction, in particular between the second working reservoir and the second ramp part. In particular, a plate is arranged between the second working reservoir and the flange portion. The flange portion preferably has friction linings. The friction linings can be arranged in particular on the second ramp part and / or on the plate. The frictionally engaged third connection between the second ramp part (and the plate) and the first shaft is formed via the flange portion.

[0051] The lamella is connected to the second shaft, particularly via leaf springs. The flange section forms the frictional third connection between the first shaft and the second ramp part (or lamella), and thus the first shaft.

[0052] The actuation of the switching element (i.e., the actuation method) occurs in particular as follows: First, the state of the switching element is determined, e.g., via a control unit. If the state includes the actuator not being actuated, actuation of the actuator is initiated. As a result of the actuation of the actuator, the first connection is established. The torque transmitted via the first connection can be adjusted by the actuator, e.g., by current control in the proposed magnetic coupling.

[0053] As a result of the torque generated via the first connection, the stator in particular is rotated relative to the intermediate element and the first working memory stores work. The intermediate element is then rotated relative to the second ramp part via the ball ramp system, so that the second ramp part is successively displaced along the axial direction. As a result of the displacement of the second ramp part, the frictionally engaged third connection is formed, through which torque is also transferred from the first shaft to the second ramp part and to the second shaft. The rotational speeds of the shafts are thus increasingly aligned with one another. As a result of the displacement of the second ramp part, the second working memory and in particular also the first working memory increasingly stores work.

[0054] As a result of the high torque to be transmitted, the intermediate element is rotated further relative to the second ramp section, so that the latter is increasingly displaced along the axial direction. In the process, the local maximum of the spring characteristic curve of the second working accumulator, which is particularly designed as a spring, is exceeded. In the region of the local minimum of the spring characteristic curve and / or after a set limit force is undershot, the work stored in the first working accumulator can cause the intermediate element to rotate relative to the second ramp section or the second shaft. This allows the second ball tracks to be aligned with the first ball tracks, and the first balls to enter the second ball tracks as a result of the now possible further displacement of the second ramp section in the axial direction.When the first balls enter the second ball tracks, the positive second connection between the first shaft and the second shaft is established.

[0055] If the actuator is no longer actuated, the second ramp section is displaced back in the axial direction via the work stored in the second working reservoir, so that the first balls exit the second ball tracks and enter the cylindrical section. The positive second connection is thus released. The second working reservoir generates only a low restoring force, especially when the second connection exists between the first shaft and the second shaft, so the actuator (especially the magnetic coupling) only needs to generate a low holding force.

[0056] The connection between the first shaft and the second shaft can be established in particular exclusively by actuating the actuator, since without actuating the actuator the shafts are arranged so that they can rotate freely relative to one another.

[0057] A drive train is proposed, comprising at least a drive unit (an electric motor) and the described shifting element, optionally additionally comprising a control unit. In particular, a separate shifting element is used for each drivable wheel. In particular, the drive train comprises a driven axle with two wheels, each wheel being switchably connectable to the drive unit via a shifting element.

[0058] The details and advantages revealed for the switching element can be transferred and applied to the drive train and vice versa.

[0059] Furthermore, a control unit is proposed via which the described switching element can be actuated and which is suitably equipped, configured or programmed to actuate the switching element.

[0060] The switching element can also be operated by a computer or by a processor in a control unit.

[0061] Accordingly, a data processing system is also proposed which comprises a processor which is adapted / configured to carry out the actuation of the switching element.

[0062] A computer-readable storage medium may be provided which includes instructions which, when executed by a computer / processor, cause the computer / processor to actuate the switching element.

[0063] The statements regarding the actuation (the method for actuation) are particularly transferable to the switching element, the drive train and / or the computer-implemented method (i.e. the computer or the processor, the data processing system, the computer-readable storage medium) and vice versa.

[0064] The use of indefinite articles ("a," "an," "one," and "another"), particularly in the patent claims and the description reproducing them, is to be understood as such and not as a numeral. Terms or components introduced accordingly are therefore to be understood as appearing at least once and, in particular, as being able to appear multiple times.

[0065] As a precaution, it should be noted that the numerals used here ("first", "second", ...) primarily serve (only) to distinguish between several similar objects, quantities, or processes, and therefore do not necessarily prescribe any interdependence and / or sequence of these objects, quantities, or processes. Should a dependence and / or sequence be necessary, this is explicitly stated here or will be obvious to the person skilled in the art upon studying the specifically described embodiment. To the extent that a component can occur multiple times ("at least one"), the description of one of these components can apply equally to all or part of the majority of these components, but this is not mandatory.

[0066] The invention and the technical environment are explained in more detail below with reference to the accompanying figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments cited. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figures and combine them with other components and findings from the present description. In particular, it should be noted that the figures, and in particular the proportions shown, are only schematic. They show: Fig. 1: a motor vehicle with a drive train; Fig. 2: a switching element in an unactuated state in a side view in section; Fig. 3: the switching element according to Fig. 2 immediately after actuation of the actuator, in a side view in section; Fig. 4: the current state of the switching element according to Fig. 2 in a diagram; Fig. 5: the switching element according to Fig. 2 and Fig. 3 after actuation of the actuator and before establishing the second connection, in a side view in section; Fig. 6: the current state of the switching element according to Fig. 5 in a diagram; Fig. 7: the switching element according to Fig. 2, Fig. 3 and Fig. 5 after making the second connection, in a side view in section; and Fig. 8: the current state of the switching element according to Fig. 7 in one diagram.

[0067] Fig. 1 shows a motor vehicle 3 with a drive train 2. The drive train 2 comprises an electric machine 41 and two first shafts 6, which can be driven by the electric machine 41. A switching element 1 can be arranged at each end of the first shafts 6. A wheel (not shown) can be connected to the electric machine 41 via each switching element 1. Each wheel is connected in a rotationally fixed manner to the respective second shaft 7 of the switching element 1. The drive train 2 here comprises a driven axle with two wheels, wherein each wheel can be switchably connected to the electric machine 41 via a switching element 1.

[0068] Fig. 2 shows a switching element 1 in an unactuated state in a side view in section. Fig. 3 shows the switching element 1 after Fig. 2 immediately after actuation of the actuator 9, in a side view in section. Fig. 4 shows the current state 40 of the switching element 1 according to Fig. 2 in a diagram. Fig. 5 shows the switching element 1 after Fig. 2 and Fig. 3 after actuation of the actuator 9 and before establishment of the second connection 11, in a side view in section. Fig. 6 shows the current state 40 of the switching element 1 according to Fig. 5 in one diagram. Fig. 7 shows the switching element 1 after Fig. 2, Fig. 3 and Fig. 5 after production of the second connection 11, in a side view in section. Fig. 8 shows the current state 40 of the switching element 1 according to Fig. 7 in one diagram.

[0069] The Fig. 2 to 8 are described together below. The explanations for Fig. 1 is referred to.

[0070] In the diagrams of the Fig. 4, Fig. 6 and Fig. In Figure 8, the distance 39 traveled by the disc spring forming the second working reservoir 19 is plotted on the horizontal axis. The force 38 acting on the disc spring in the axial direction 4 is shown on the vertical axis. The diagrams each show the course of the spring characteristic curve 21 of the disc spring. The point shown in each diagram indicates the current state 40 of the switching element 1 and the deformation of the disc spring present in this state.

[0071] The switching element 1 has a rotational axis 5 extending along an axial direction 4 and comprises a first shaft 6, a second shaft 7 arranged coaxially to the first shaft 6, and a switching device 8 for switchably connecting the shafts 6, 7. The switching device 8 has an actuator 9 for switching the connection. To connect the shafts 6, 7, the actuator 9 first establishes a frictionally engaged first connection 10 between the shafts 6, 7 (via additional components), which then results in a positively engaged second connection 11 between the shafts 6, 7.

[0072] The connection of the shafts 6, 7 is made successively. First, after actuation of the actuator 9, the first connection 10 is established (see Fig. 3). As a result of the first connection 10, the different speeds of the shafts 6, 7 are synchronized (i.e., aligned). The second connection 11 is only initialized after the first connection 10 has been established (see Fig. 7).

[0073] The second connection 11 is formed automatically (e.g., when there is a differential speed between the first shaft 6 and the second shaft 7), i.e., without additional actuation of the actuator 9. However, the second connection 11 is only formed if the actuator 9 was actuated to establish the first connection 10 and is still actuated. When the actuation of the actuator 9 ends, the first connection 10 and thus also the second connection 11 are released.

[0074] The actuator 9 is designed as a magnetic coupling comprising a plurality of magnets (or windings of an electromagnet) 12, a rotary transformer 13 connected in a rotationally fixed manner to the first shaft 6, and a stator 14 connected to the second shaft 7 (via further components). By energizing the magnets 12, the stator 14 can be displaced along the axial direction 4 to form the first connection 10 with the rotary transformer 13.

[0075] The rotary transformer 13 is arranged along the axial direction 4 between the magnets 12 and the stator 14.

[0076] The rotary joint 13 is connected to the first shaft 6 in a rotationally fixed manner. The stator 14 is connected (via additional components) to the second shaft 7, so that the first shaft 6 can be connected to the second shaft 7 via the frictionally engaged first connection 10 between the rotary joint 13 and the stator 14.

[0077] The magnets 12 are connected in a rotationally fixed manner to a housing 42 of the switching device 8, wherein the first shaft 6 is arranged rotatably relative to the housing 42 via a first bearing 36.

[0078] A current control of actuator 9 can be used to regulate the contact force between rotary transformer 13 and stator 14. Current control can be performed via a control unit.

[0079] The shafts 6, 7 are connected via a first working storage device 15, which allows the components connected to one another via the first working storage device 15 to rotate relative to one another within a limited first angular range, thereby storing the energy required for the rotation. The first working storage device 15 comprises a plurality of springs, here arc springs, which are deformable at least relative to a circumferential direction 16 to store energy.

[0080] The shafts 6, 7 can be connected to one another via further components (in this case via the rotary transformer 13, the stator 14, an intermediate element 18 with a first ramp part 32, a second ramp part 47, a ball ramp system 17 formed by the intermediate element 18 and the second ramp part 47, a frictionally engaged third connection 20, the first balls 24), so that the shafts 6, 7 (even when the first connection 10 has been established) can be rotated relative to one another over a larger angular range than the first angular range.

[0081] The first working memory 15 enables the second connection 11 to be established only after the speeds of the shafts 6, 7 have been synchronized.

[0082] The switching device 8 has an intermediate element 18 that can be connected to the first shaft 6 only via the first connection 10 and is connected to the second ramp part 47 via a ball ramp system 17. The intermediate element 18 and the second ramp part 47 are connected to each other via the ball ramp system 17 so as to be rotatable by a limited second angular range. The second ramp part 47 is displaceable along the axial direction 4 via the ball ramp system 17 upon a relative rotation of the intermediate element 18 with respect to the second ramp part 47 to form the second connection 11 with the first shaft 6. The ball ramp system 17 is designed such that, starting from a non-displaced arrangement of the second ramp part 47 (see Fig. 2) the intermediate element 18 with the first ramp part 32 is rotatable in both directions of rotation relative to the second ramp part 47, so that upon relative rotation in both directions of rotation, the second ramp part 47 is displaced in the axial direction 4. Likewise, the first working memory 15 is designed such that, starting from a non-displaced arrangement of the second ramp part 47, the intermediate element 18 is rotatable in both directions of rotation relative to the second ramp part 47.

[0083] The intermediate element 18 is connected to the stator 14 via the first working memory 15, so that the intermediate element 18 can be rotated relative to the stator 14 by the limited first angular range.

[0084] The intermediate element 18 is rotatably mounted on the first shaft 6 via a second bearing 37.

[0085] The intermediate element 18 has a plurality of first ramps 28 on a first ramp part 32 connected to the intermediate element 18, and the second ramp part 47 has a corresponding plurality of second ramps 29, which form the ball ramp system 17. A second ball 30 is arranged between each of the ramps 28, 29. The ramps 28, 29 extend in the circumferential direction 16.

[0086] The second shaft 7 extends into the intermediate element 18. The second ramp part 47 is arranged within a sleeve section of the second shaft 7 and can be displaced relative to the second shaft 7 along the axial direction 4. The second ramp part 47 is connected to the second shaft 7 or to the lamella 35 via leaf springs (not shown here). The flange section 34 of the cage element 33 is arranged within the sleeve section of the second shaft 7 and along the axial direction 4 between the second ramp part 47 and the lamella 35 or the second working accumulator 19. The lamella 35 is fastened to the second shaft 7 via leaf springs 49 so that a torque of the lamella 35 can be supported on the second shaft 7 via the leaf springs 49. The lamella 35 is supported on the second shaft 7 relative to the axial direction 4, so that when the second ramp part 47 is not displaced (see Fig. 2 and Fig. 3) the third connection 20 is not present.

[0087] When the first connection 10 is established, an adjustable torque is transmitted between the first shaft 6 and the switching device 8. This torque causes a rotation of the intermediate element 18 or the first ramp part 32 relative to the second ramp part 47, so that the second ramp part 47 is displaced along the axial direction 4 via the ball ramp system 17 (see Fig. 5).

[0088] The switching device 8 comprises a second working memory 19, which stores the work required to displace the second ramp part 47 along the axial direction 4. Only after the second ramp part 47 has been displaced along the axial direction 4 can the second connection 11 between the first shaft 6 and the second shaft 7 be established.

[0089] The second shaft 7 can be connected to the first shaft 6 via a frictionally engaged third connection 20 as a result of the displacement of the second ramp part 47 along the axial direction 4 (see Fig. 5).

[0090] The second working storage 19 comprises a disc spring which is deformable at least relative to the axial direction 4 for storing work.

[0091] The spring has a spring characteristic curve 21 with a local minimum 22, wherein the switching device 8 can be configured such that the second connection 11 occurs only in a region 23 of the local minimum 22.

[0092] The spring has a spring characteristic curve 21 with a local maximum 31. Starting from an unactuated switching element 1, the spring is successively deformed when the switching element 1 is actuated by the displacement of the second ramp part 47 along the axial direction 4, so that initially the local maximum 31 (see Fig. 5 and Fig. 6) is exceeded and the (spring) force 38 gradually decreases towards the local minimum 22 with further deformation. The local maximum 31 is only exceeded by a corresponding actuation of the actuator 9 (at a correspondingly high current).

[0093] The second connection 11 occurs in a state of the switching device 8 that lies between the local maximum 31 and the local minimum 22, here in a flat state of the spring. Preferably, the spring is overcompressed, so that the second connection 11 occurs in a region 23 (see in Fig. 8), which, starting from the local maximum 31, lies close to or immediately before the local minimum 22.

[0094] The spring is relaxed in an unactuated state of the switching element 1 or the switching device 8, i.e. arranged without force (see Fig. 2 and Fig. 3). The spring is only increasingly tensioned when the actuator 9 is actuated and during the successive establishment of the first connection 10.

[0095] The second connection 11 is made by a plurality of first balls 24, each first ball 24 being arranged on the one hand in every state of the switching device 8 in a first ball track 25 of the first shaft 6 running along the axial direction 4 and on the other hand, and only in the state of the switching device 1 with the established second connection 11 (see Fig. 7), in a second ball track 26 of the second shaft 7 running along the axial direction 4 and in another state (see Fig. 2, Fig. 3, Fig. 5) is arranged outside the second ball track 26 in a cylindrical section 27 of the second shaft 7.

[0096] The cylindrical portion 27 is designed to be circumferential in the circumferential direction 16 and extends along the axial direction 4, so that when the first balls 24 are arranged in the cylindrical portion 27, the second shaft 7 is freely rotatable relative to the first balls 24 arranged in the first ball tracks 25.

[0097] If the first balls 24 are arranged in the cylindrical section 27, the second shaft 7 is freely rotatable relative to the first shaft 6, possibly only limited by the frictional first connection 10 and / or the frictional third connection 20.

[0098] As a result of the displacement of the second ramp part 47 along the axial direction 4, the first balls 24 can be transferred from the cylindrical section 27 into the second ball tracks 26, thus creating the second connection 11 that is positively locked relative to the circumferential direction 16. This is only possible due to the stored energy of the first working accumulator 15, since as soon as the positive locking takes effect, there is no longer any differential speed between the shafts 6, 7.

[0099] A cage element 33 is arranged between the first shaft 6 and the second shaft 7. This cage element 33 comprises a cylindrical sleeve portion 44 that extends along the axial direction 4 between the first shaft 6 and the second shaft 7 and has a plurality of windows 45. One of the first balls 24 is arranged in each window 45.

[0100] The cage element 33 comprises a flange section 34 extending outwardly from the sleeve section 44 in a radial direction 43. The flange section 34 is arranged along the axial direction 4 between the second working accumulator 19 and the second ramp part 47. A plate 35 is arranged between the second working accumulator 19 and the flange section 34. The flange section 34 has friction linings 46. The frictionally engaged third connection 20 between the second ramp part 47 and the plate 35 (as well as the second shaft 7) and the first shaft 6 is formed via the flange section 34.

[0101] The first ball tracks 25 extending in the axial direction 4 to the end of the first shaft 6 are limited by a stop provided on the second shaft 7 (the end of the second ball tracks 26).

[0102] The first shaft 6 extends along the axial direction 4 through a housing 42, in which it is rotatably mounted via a first bearing 36. The first shaft 6 extends along the axial direction 4 through the rotary transformer 13, the stator 14, the intermediate element 18 with the first ramp part 32, the second ramp part 47, the first working reservoir 15, the second working reservoir 19, and the lamella 35. The second shaft 7 is arranged coaxially to the first shaft 6 and overlaps the first shaft 6 in the area of ​​the ball tracks 25, 26 and the cylindrical section 27.

[0103] The actuation of the switching element 1 (i.e., the actuation method) is as follows: first, a state of the switching element 1 is determined, e.g., via a control unit. If the state includes that the actuator 9 is not actuated and that a torque transmission between the first shaft 6 and the second shaft 7 is desired, an actuation of the actuator 9 is initiated. As a result of the actuation of the actuator 9, the first connection 10 is established (see Fig. 3). The torque transmitted via the first connection 10 can be adjusted by the actuator 9, e.g., by current control in the proposed magnetic coupling.

[0104] As a result of the torque generated via the first connection 10, the stator 14 is rotated relative to the intermediate element 18, and the first working storage element 15 stores work. Subsequently, or at the same time, the intermediate element 18 is rotated relative to the second ramp part 47 (which is connected to the second shaft 7 via leaf springs) via the ball ramp system 17, so that the second ramp part 47 is successively displaced along the axial direction 4 (see Fig. 5). As a result of the displacement of the second ramp portion 47, the frictionally engaged third connection 20 is formed, through which torque is also transmitted from the first shaft 6 to the second shaft 7. The rotational speeds of the shafts 6, 7 are thus increasingly aligned. As a result of the displacement of the second ramp portion 47, the second working storage unit 19 increasingly stores work.

[0105] As a result of a high torque to be transmitted, the intermediate element 18 is further rotated relative to the second ramp part 47, so that the latter is increasingly displaced along the axial direction 4. In the process, the local maximum 31 of the spring characteristic curve 21 of the second working accumulator 19, which is designed as a spring, is exceeded. After falling below an adjustable limit force 48, the work stored in the first working accumulator 15 can cause a (further) rotation of the second shaft 7 relative to the first shaft 6. This allows the second ball tracks 26 to be aligned with the first ball tracks 25, and the first balls 24 to enter the second ball tracks 26 as a result of the now possible further displacement of the second ramp part 47 in the axial direction 4 (see Fig. 7). When the first balls 24 enter the second ball tracks 26, the positive second connection 11 is established.

[0106] If the actuator 9 is no longer actuated, the second ramp part 47 is displaced back in the axial direction 4 via the work stored in the second working memory 19, so that the first balls 24 exit the second ball tracks 26 and enter the cylindrical section 27. The positive second connection 11 is thus released.

[0107] The connection between the first shaft 6 and the second shaft 7 can only be established by actuating the actuator 9, since without actuating the actuator 9 the shafts 6, 7 are arranged so as to be freely rotatable relative to one another.

Claims

[1] Switching element (1) with a rotational axis (5) extending along an axial direction (4), comprising a first shaft (6), a second shaft (7) arranged coaxially to the first shaft (6), and a switching device (8) for switchably connecting the shafts (6, 7); wherein the switching device (8) has an actuator (9) for switching the connection, wherein, in order to connect the shafts (6, 7), the actuator (9) can first establish a frictionally engaged first connection (10) of the shafts (6, 7), thereby creating a subsequent positively engaged second connection (11) of the shafts (6, 7); wherein the second shaft (7) is arranged stationary relative to the first shaft (6) with respect to the axial direction (4), characterized by that the switching device (8) at least • an intermediate element (18) which can be connected to the first shaft (6) only via the first connection (10), which comprises a first ramp (28) of a ball ramp system (17) which is arranged stationary relative to the first shaft (6) with respect to the axial direction (4); and • a second ramp part (47) which is displaceable relative to the intermediate element (18) along the axial direction (4), said second ramp part comprising a second ramp (29) which interacts with the first ramp (28) as a ball ramp system (17); wherein the second ramp part (47) and the intermediate element (18) are connected to one another via the ball ramp system (17) so as to be rotatable by a limited second angular range; wherein the second ramp part (47) is displaceable relative to the second ramp part (47) via the ball ramp system (17) along the axial direction (4) upon a relative rotation of the intermediate element (18), and as a result of this displacement, the second connection (11) between the first shaft (6) and the second shaft (7) can be established. [2] Switching element (1) according to claim 1, wherein the actuator (9) is a magnetic coupling which has at least one magnet (12), a rotary transformer (13) connected in a rotationally fixed manner to the first shaft (6) and a stator (14) connected to the second shaft (7), wherein by energizing the magnet (12) the stator (14) can be displaced along the axial direction (4) to form the first connection (10) with the rotary transformer (13). [3] Switching element (1) according to one of the preceding claims, wherein the connection of the shafts (6, 7) is effected via a first working memory (15) which allows a relative rotation of the components connected via the first working memory (15) to one another by a limited first angular range and thereby stores the work required for the rotation. [4] Switching element (1) according to claim 3, wherein the first working storage (15) comprises at least one spring which is deformable at least with respect to a circumferential direction (16) for storing work. [5] Switching element (1) according to one of the preceding claims, wherein the switching device (8) comprises a second working memory (19) which stores the work required for displacing the second ramp part (47) along the axial direction (4); wherein the second connection (11) between the first shaft (6) and the second shaft (7) can only be established after the second ramp part (47) has been displaced. [6] Switching element (1) according to claim 5, wherein the second shaft (7) is connectable to the first shaft (6) via a frictional third connection (20) as a result of the displacement of the second ramp part (47) along the axial direction (4). [7] Switching element (1) according to one of the preceding claims 5 and 6, wherein the second working storage (19) comprises a spring which is deformable at least with respect to the axial direction (4) for storing work. [8] Switching element (1) according to claim 7, wherein the spring has a spring characteristic (21) with at least one local minimum (22), wherein the switching device (8) is arranged such that the second connection (11) only takes place in a region (23) of the local minimum (22). [9] Switching element (1) according to one of the preceding claims, wherein the second connection (11) is made by a plurality of first balls (24), wherein each first ball (24) is arranged, on the one hand, in every state of the switching device (8) in a first ball track (25) of the first shaft (6) running along the axial direction (4) and, on the other hand and only in the state of the switching device (8) with the established second connection (11), in a second ball track (26) of the second shaft (7) running along the axial direction (4) and, in another state, outside the second ball track (26) in a cylindrical section (27) of the second shaft (7).

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