Secondary device for an inductive transmission device

Abstract

A secondary device (1) for an inductive transmission device for an electric machine, in particular a separately excited electric machine for a motor vehicle, said secondary device comprising a secondary ferrite core (2) and a control apparatus (4) which is positioned at least partially on a cooling device (3) and is designed to rectify an electrical signal transmitted to the secondary device (1), wherein an intermediate element (10) is located between the secondary ferrite core (2) and a heat sink (7), said intermediate element being designed such that, when the secondary device is fitted in a rotor shaft (9) of the electric machine, the intermediate element positions the secondary ferrite core (2) and / or the heat sink (7) in the rotor shaft (9).

Description

[0001] Secondary device for an inductive transmission device

[0002] The invention relates to a secondary device for an inductive transformer device for an electric machine, in particular a separately excited electric machine for a motor vehicle, comprising a secondary ferrite core and a control device arranged at least partially on a cooling device, which is designed to rectify an electrical signal transmitted to the secondary device.

[0003] Secondary devices designed for inductive transmission in inductive excitation devices for separately excited electrical machines, particularly in applications as drive units for motor vehicles, are generally known from the prior art. Such secondary devices are known to include a control device configured to rectify the electrical signal transmitted to the secondary device via the inductive excitation device, i.e., transmitted from the primary to the secondary side, in order to subsequently supply it to the rotor windings of the electrical machine.

[0004] In the operation of such secondary equipment, it is further known that heat is generated, for example, due to electrical losses in the control unit. This generated heat must be dissipated from the electronic components of the secondary equipment to ensure continuous operation at a defined power output. It is known, for example, that the control unit can be arranged on a cooling unit in such a way that the cooling unit can conduct heat into the rotor shaft in a defined manner. For example, a circuit board of the cooling unit is circular and arranged perpendicular to the axis of rotation of the secondary equipment or the rotor shaft, within the rotor shaft.

[0005] Depending on the available installation space, for example the diameter of the rotor shaft, and depending on which electronic components of the control device are to be provided, for example a number of rectifier diodes, the design of a protection circuit and the like, such an arrangement is not or only with difficulty feasible, since the diameter of the cooling device is limited, so that the diameter of the rotor shaft cannot be arbitrarily set below a minimum dimension or not arbitrary rectifier devices can be used in the control device.

[0006] The invention is based on the objective of providing an improved secondary device for an inductive transformer device for a separately excited electric machine, in which the design freedom with regard to the dimensions of the secondary device, in particular adapted to a rotor shaft, and / or the design of the control device is improved.

[0007] The problem is solved by a secondary device having the features of claim 1. Advantageous embodiments are the subject of the dependent claims.

[0008] As described, the invention relates to a secondary device for an inductive transformer for an electric machine. The electric machine is, for example, a separately excited electric machine for a motor vehicle. Specifically, the electric machine is configured as a drive unit for the motor vehicle. The secondary device comprises a secondary ferrite core and a cooling unit, on which a control device is arranged, at least partially, in particular on a heat sink of the cooling unit. The control device is configured, at least, to rectify the electrical signal transmitted to the secondary device. For example, the control device rectifies the electric current transmitted to the secondary device from the primary device.

[0009] The invention is based on the finding that the secondary device has an intermediate element arranged between the secondary ferrite core and the heat sink, which is designed to position the secondary ferrite core and / or the heat sink within the rotor shaft when the secondary device is mounted in a rotor shaft of the electric machine. The heat sink is, in particular, aligned with its longitudinal axis along the axis of rotation of the secondary device or the rotor shaft. The longitudinal axis of the heat sink is, in particular, arranged parallel to the axis of rotation. It is known that during operation of the control device, for example, during operation of the rectifier elements used to rectify the electrical signal, specifically rectifier diodes, heat is generated, which is dissipated via the cooling device. For example, the heat is transferred directly into the heat sink, which is in contact with the rotor shaft, at least partially.

[0010] Therefore, it is crucial for both the secondary ferrite core and the heat sink to be correctly positioned within the rotor shaft. For example, if the heat sink is incorrectly positioned, contact with the rotor shaft can be lost, at least partially, thus impairing heat conduction. The intermediate element ensures the correct positioning of the secondary ferrite core and the heat sink, guaranteeing their correct alignment within the rotor shaft relative to the axis of rotation. Specifically, this ensures that the heat sink makes defined contact with at least one section of the rotor shaft's inner wall, thereby guaranteeing efficient heat conduction regardless of the specific operating state of the electric machine in all rotor positions and orientations.

[0011] The secondary device may be designed so that the intermediate element supports the heat sink in an assembly state with a defined radial overhang, which overhang can be reduced by applying a preload force when transitioning to the assembled state. In principle, the present application distinguishes between the "assembly state" and the "assembled state." The assembly state exists, in particular, when the secondary device is not yet mounted in the rotor shaft, and the assembled state exists when the assembly is complete, i.e., when the secondary device is installed in the rotor shaft.

[0012] In the described embodiment, in the assembled state, i.e., when the secondary device is arranged outside the rotor shaft, there should be a defined projection between the intermediate element and the heat sink, relative to the axis of rotation of the secondary device. In other words, the heat sink projects further radially from the axis of rotation than the outer surface of the intermediate element. The intermediate element can generally be a cylindrical or disc-shaped body. Its outer radial position is therefore defined by the outer surface of the intermediate element. The heat sink projects beyond this surface by the defined amount, so that the extent of the heat sink, or its maximum distance from the axis of rotation, is greater than that of the intermediate element in the assembled state.

[0013] When the secondary device is moved into the assembled state, i.e., inserted into the rotor shaft, this protrusion is eliminated, since, in particular, the diameter of the intermediate element corresponds to the inner diameter of the rotor shaft, and the intermediate element and heat sink are in contact with the rotor shaft. During the transition to the assembled state, the arrangement of the heat sink relative to the intermediate element, as it exists in the assembled state, is therefore deformed, and this deformation creates a preload force.

[0014] The preload force therefore tends to move the heat sink back to its initial position, particularly in the radial direction. This ultimately preloads the heat sink radially against the inner wall of the rotor shaft. The secondary assembly can be, in particular, a pre-assembled unit that can be installed as a single unit in the rotor shaft. The arrangement of the heat sink on the intermediate element and the secondary ferrite core on the intermediate element ensures that neither component is lost, thus enabling their assembly together in the rotor shaft.

[0015] In one embodiment of the secondary device, at least one connecting element may be provided between the heat sink and the intermediate element. This connecting element includes a spring that can be pre-tensioned when transitioning to the assembled state. As described, the reduction of the radial overhang or the action of the rotor shaft's inner wall on the heat sink deflects the heat sink from the radial position it assumes in the assembled state. When the assembled state is reached, the heat sink is moved relative to the intermediate element, as described. This pre-tensions the spring element.

[0016] The described spring element can, in principle, be of any design. In a further development of the secondary device, the spring element can be formed by at least one, and in particular at least two, axially extending bolts, which are received in a receptacle having two receiving diameters. The bolt can be located on the intermediate element, and the receptacle can be located on or in the heat sink. It is also possible for the receptacle to be located on or in the intermediate element, and the bolt to be located on the heat sink.

[0017] In this case, a larger mounting diameter can be provided facing the interface between the intermediate element and the heat sink, and a smaller mounting diameter can be provided at a distance from the interface. For example, the smaller mounting diameter corresponds to the bolt diameter.

[0018] Due to the larger mounting diameter, it is possible that the bolt held in the smaller mounting diameter can deform relative to the intermediate element when the heat sink moves. The different mounting diameters can be achieved, for example, by means of a stepped bore.

[0019] Alternatively or additionally, the described spring element, in particular a leaf spring, can be arranged on the intermediate element and the heat sink, with the spring element extending through an axially extending deformation space. Analogous to the previously described embodiment in which the spring element is designed as a bolt, the spring element can be undeformed in the assembly state. When the assembled state is assumed, i.e., when the heat sink is moved from the assembly state to the mounted state, in particular in the radial direction towards the axis of rotation, the spring element is deformed and thus builds up the preload force in the radial direction on the heat sink, causing it to move against the inner wall of the rotor shaft. The axially extending deformation space allows the spring element to deform.

[0020] In principle, the arrangement of the heat sink on the intermediate element is arbitrary, as long as the previously described preload or reduction of the radial overhang can be achieved. For example, the secondary device may be designed so that the heat sink is positively connected to the intermediate element, in particular by means of an axially extending engagement element that engages in a radially extending groove. The engagement element may, in particular, be T-shaped and engage in a correspondingly shaped groove.

[0021] In a further embodiment, the heat sink can be secured radially to the intermediate element by means of a locking element engaging axially in a groove, wherein at least one spring element is provided which preloads the heat sink radially such that the locking element rests against an inner wall of the groove and / or that the heat sink is connected to the intermediate element by means of a spring-loaded locking element, in particular a locking ball, which is guided in a contour, wherein the locking element is arranged in a potential well of the contour in the assembly state and, upon transition to the assembled state, the heat sink can be preloaded radially against the intermediate element by deflecting the locking element out of the potential well.

[0022] In the first described alternative, the locking element, for example a locking lug or a barb, can engage axially in a groove. The locking element rests against a section of the groove when it is radially pre-tensioned by the spring element. In other words, the spring element pre-tensions the locking element radially against the inner wall of the groove. This ensures that the heat sink remains radially pre-tensioned, particularly against the inner wall of the rotor shaft.

[0023] In the second described alternative, a detent element, for example a detent ball, is spring-mounted and guided within a contour. For instance, the intermediate element has a contour, such as a recess, which, viewed in a longitudinal section of the secondary device, is triangular in shape. The recess therefore has a ramped shape. The recess or contour thus forms a potential well, particularly in the assembled state. If the heat sink is deflected from its assembled state, the detent element, which is spring-mounted within the heat sink, for example in a pocket, is deflected out of the potential well. This creates a restoring force that tends to return the detent element to the potential well. This preloads the heat sink in the radial direction.

[0024] In a further embodiment of the secondary device, the heat sink can be connected to the intermediate element by means of at least one magnetic device, wherein the magnetic device comprises at least one first magnetic element, in particular a permanent magnet, and at least one second magnetic element, in particular a magnetizable counterpart, wherein the at least two magnetic elements are arranged axially on a common axis in the assembly state and, upon transition to the assembled state, the heat sink is radially biased against the intermediate element by deflection of the magnetic elements. In other words, the two magnetic elements are arranged in the assembly state such that a potential well is formed. In other words, the magnetic elements "attract" the heat sink to the intermediate element in such a way that the alignment is achieved in the assembly state.During the transition to the assembled state, the previously described positioning is deflected, causing the magnetic elements to strive to regain their alignment in the assembled state. This results in the preload force between the intermediate element and the heat sink, which preloads the heat sink radially against the inner wall of the rotor shaft.

[0025] In addition to the secondary device, the invention relates to an inductive transformer device comprising a previously described secondary device. Furthermore, the invention relates to an electric machine comprising a previously described secondary device and / or a previously described inductive transformer device. Finally, the invention relates to a motor vehicle comprising a previously described inductive transformer device and / or a previously described electric machine and / or a previously described secondary device.

[0026] All advantages, details and features described in relation to the secondary device are freely transferable to the inductive transformer device, the electric machine and the motor vehicle.

[0027] The invention is explained below with reference to exemplary embodiments and the figures. The figures are schematic representations and show:

[0028] Fig. 1 shows a schematic representation of a secondary device for an inductive transmission device for an electric machine;

[0029] Fig. 2 shows a detail of a connection between an intermediate element and a heat sink in the vertical direction;

[0030] Fig. 3 shows a detail of a schematic representation of a longitudinal section of a secondary device in an assembly state according to a first embodiment;

[0031] Fig. 4 shows the detail of Fig. 3 in an assembled state;

[0032] Fig. 5 shows a detail of a schematic representation of a longitudinal section of a secondary device in an assembly state according to a second embodiment;

[0033] Fig. 6 shows the detail of Fig. 5 in an assembled state;

[0034] Fig. 7 shows a detail of a schematic representation of a longitudinal section of a secondary device in an assembly state according to a third embodiment;

[0035] Fig. 8 shows the detail of Fig. 7 in an assembled state;

[0036] Fig. 9 shows a detail of a schematic representation of a longitudinal section of a secondary device in an assembled state according to a fourth embodiment; Fig. 10 shows the detail of Fig. 9 in an assembled state; and

[0037] Fig. 11 shows a detail of a schematic representation of a longitudinal section of a secondary device in an assembled state according to a fifth embodiment.

[0038] Fig. 1 shows a schematic longitudinal section through a secondary device 1 for an inductive transformer device (not shown in detail). In addition to the secondary device 1, the inductive transformer device includes, for example, a primary device configured to inductively transmit an electrical signal, in particular an electric current, to the secondary device 1. The secondary device 1 further includes a secondary ferrite core 2 and a control device 4 arranged at least partially on a cooling device 3. The control device 4 includes, for example, rectifier elements 5, such as rectifier diodes, configured to rectify the transmitted electrical signal. The control device 4 may optionally include a protective circuit 6. The cooling device 3 includes a heat sink 7 on which the control device 4 is arranged.For example, the control device 4 may include an IMS board or other circuit board mounted on the heat sink 7.

[0039] The heat sink 7 extends in the axial direction, i.e., in particular, that a longitudinal axis of the heat sink 7 extends parallel to a rotational axis 8 of the secondary device 1. In the assembled state of the secondary device 1, which is shown in particular in Figs. 4, 6, 8, 10 and 11, the cooling device 3 with its heat sink 7 is in defined contact with a rotor shaft 9 of the electric machine which has the secondary device 1.

[0040] To ensure or establish the alignment of the secondary ferrite core 2 and the cooling device 3, the secondary device 1 has an intermediate element 10. The intermediate element 10 is arranged axially with respect to the axis of rotation 8 between the secondary ferrite core 2 and the cooling device 3. The intermediate element 10 is further designed to ensure this positioning, in particular to preload the cooling device 3 against the inner wall of the rotor shaft 9 in a defined manner.

[0041] Fig. 2 shows that the intermediate element 10 has a T-shaped engagement element 11 that engages in a correspondingly shaped groove 12 in the heat sink 7. For example, in the illustration shown in Fig. 1, the heat sink 7 can be pushed onto the intermediate element 10 in the vertical direction, i.e., radially in the direction of the axis of rotation 8 "from below," or in Fig. 2 into the plane of the image. To ensure the radial positioning of the heat sink 7, Figs. 3-11 show various embodiments of spring elements that preload the heat sink 7 in the assembled state, in particular relative to the intermediate element 10 and against the inner wall of the rotor shaft 9. The embodiment described above with reference to Figs. 1 and 2, comprising the engagement element 11 and the groove 12, can also be provided, for example, in the embodiments shown in Figs. 7-11.

[0042] Figure 3 illustrates that the described spring element can be configured as a bolt 13 and engage axially in a receptacle 14. Although the receptacle 14 is shown in the heat sink 7 and the bolt 13 in the intermediate element 10 as examples, a reverse configuration is also possible. The receptacle 14 has a first receiving diameter 15 and a second receiving diameter 16. For example, the receptacle 14 is configured as a stepped bore. The larger receiving diameter 16 faces the interface between the intermediate element 10 and the heat sink 7. The smaller receiving diameter 15 can, for example, correspond to the outer diameter of the bolt 13. In the assembly configuration shown in Figure 3, a radial projection 17 results, by which the heat sink 7 extends radially beyond the outer surface of the intermediate element 10.

[0043] When the secondary device 1 is inserted into the rotor shaft 9, the protrusion 17 is reduced, as the intermediate element 10 and the heat sink 7 then rest against the inner wall of the rotor shaft 9. To reduce the protrusion 17, the bolt 13, of which several bolts 13 may be provided circumferentially, is deformed. This deformation is permitted by the larger receiving diameter 16, as shown in Fig. 4. The deformation of the bolt 13 causes it to return the heat sink 7 to the position it was in during assembly, as shown in Fig. 3. In other words, the bolt 13 presses the heat sink 7 radially against the inner wall of the rotor shaft 9, i.e., "downwards" in Fig. 4.

[0044] Fig. 5 shows an assembly state of the secondary device 1 in a further embodiment of a spring element. In Figs. 5 and 6, the spring element can, for example, be designed as a leaf spring 18. As can be seen in Fig. 5, the leaf spring 18 is relaxed in the assembly state. When the assembled state shown in Fig. 6 is assumed, the leaf spring 18 is deformed so that it exerts a spring force on the cooling element 7, which biases the cooling element 7 against the rotor shaft 9. Any other spring element can be used instead of the leaf spring 18. The leaf spring 18 is associated with a deformation space 19, which, similar to the larger mounting diameter in the embodiment described above, allows deformation of the leaf spring 18, as shown in Fig. 6.

[0045] Figures 7 and 8 show a further embodiment of the secondary device 1, in which a spring-loaded detent element 20 is provided that engages in a contour 21. The contour 21 has at least one ramp 22 against which the detent element 20 rests. The contour 21 can be seen forming a potential well in which the detent element 20 rests in the assembly state shown in Figure 7. When the secondary device 1 is inserted into the rotor shaft 9, the cooling element 7 is displaced radially relative to the intermediate element 10 in the direction of the axis of rotation 8.

[0046] As shown in Fig. 8, this causes the detent element 20 to be deflected out of the potential well and moved along the ramp 22, thereby pre-tensioning the spring. This creates a restoring force that tends to move the heat sink 7 back to its initial position. In other words, this also pre-tensions the heat sink 7 against the rotor shaft 9.

[0047] Figures 9 and 10 show a further embodiment of the secondary device 1, in which the heat sink 7 is connected to the intermediate element 10 by means of at least one magnetic device 23. A first magnetic element 24 is provided, which is, for example, designed as a permanent magnet. Furthermore, a second magnetic element 25 is provided in the magnetic device 23, which is, for example, designed as a magnetizable counterpart for the first magnetic element 24. As shown in Figure 9 in the illustrated assembly state, the two magnetic elements 24 and 25 lie on a common axis in the axial direction.

[0048] When the secondary device 1 is inserted into the rotor shaft 9, the heat sink 7 is deflected from the position shown in Fig. 9, causing the magnetic elements 24, 25 to shift relative to each other. Correspondingly, the magnetic elements 24, 25 tend to return to their initial state, thus also creating a preload force on the heat sink 7, which biases the heat sink 7 against the inner wall of the rotor shaft 9.

[0049] Fig. 11 shows another embodiment in which a locking element 26 engages axially in a groove 27. In this embodiment, the locking element 26 is arranged on the intermediate element 10 and the groove 27 on the heat sink 7, although the reverse is also possible. A spring element 28 is also shown, which exerts a spring force radially on the heat sink 7. This presses the heat sink 7 radially against the rotor shaft 9. This ensures that the heat sink 7 rests against the locking element 26 with the inner wall of the groove 27.

[0050] The advantages, details, and features shown in the individual embodiments can be combined, interchanged, and transferred to one another as desired. (Reference symbol)

[0051] Secondary device, secondary ferrite core, cooling device, control device

[0052] rectifier element

[0053] Protection circuit

[0054] heat sink

[0055] axis of rotation

[0056] Rotor shaft

[0057] Intermediate element

[0058] Intervention element

[0059] Nut

[0060] bolt

[0061] Mounting, 16 mounting diameter

[0062] Overhang

[0063] leaf spring

[0064] Deformation space

[0065] Latching element

[0066] contour

[0067] ramp

[0068] Magnetic device, 25 magnetic elements

[0069] Latching element

[0070] Nut

[0071] spring element

Claims

Patent claims 1. Secondary device (1) for an inductive transformer device for an electric machine, in particular a separately excited electric machine for a motor vehicle, comprising a secondary ferrite core (2) and a control device (4) arranged at least partially on a cooling device (3), which is designed to rectify an electrical signal transmitted to the secondary device (1), characterized in that an intermediate element (10) is arranged between the secondary ferrite core (2) and a heat sink (7), which is designed to position the secondary ferrite core (2) and / or the heat sink (7) within the rotor shaft (9) in a state of the secondary device (1) mounted in a rotor shaft (9) of the electric machine.

2. Secondary device (1 ) according to claim 1 , characterized in that the intermediate element (10) supports the cooling element (7) in an assembly state with a defined radial projection (17), which projection (17) can be reduced when transitioning to the assembled state by building up a preload force.

3. Secondary device (1 ) according to claim 1 or 2, characterized in that at least one connecting device is provided between the cooling element (7) and the intermediate element (10), which has a spring element that can be pre-tensioned when transitioning to the assembled state.

4. Secondary device (1 ) according to claim 3, characterized in that the spring element is provided by at least one, in particular at least two, axially extending bolts (13) which are received in a receptacle (14) having two receiving diameters (15, 16).

5. Secondary device (1) according to claim 3 or 4, characterized in that the spring element, in particular designed as a leaf spring (18), is arranged on the intermediate element (10) and the cooling element (7), wherein the spring element extends through a deformation space (19) extending in the axial direction.

6. Secondary device (1 ) according to one of the preceding claims, characterized in that the cooling element (7) is positively connected to the intermediate element (10), in particular by means of an axially extending engagement element (11) which engages in a radially extending groove (17).

7. Secondary device (1) according to one of the preceding claims, characterized in that the heat sink (7) is secured radially to the intermediate element (10) by means of a locking element (26) engaging axially in a groove (27), wherein at least one spring element (28) is provided which preloads the heat sink (7) radially such that the locking element (26) bears against an inner wall of the groove (27) and / or that the heat sink (7) is connected to the intermediate element (10) by means of a spring-loaded locking element (20), in particular a locking ball which is guided in a contour (21), wherein the locking element (20) is arranged in a potential well of the contour (21) in the assembly state and can be preloaded radially against the intermediate element (10) by deflecting the locking element (20) out of the potential well of the heat sink (7).

8. Secondary device (1) according to one of the preceding claims, characterized in that the heat sink (7) is connected to the intermediate element (10) by means of at least one magnetic device (23), wherein the magnetic device (23) comprises at least one first magnetic element (24), in particular a permanent magnet, and at least one second magnetic element (25), in particular a magnetizable counterpart, wherein the at least two magnetic elements (24, 25) are arranged axially on a common axis in the assembly state and, upon transition to the assembled state, the heat sink (7) can be biased radially against the intermediate element (10) by deflecting the magnetic elements (24, 25).

9. Inductive transformer device comprising a secondary device (1) according to any of the preceding claims.

10. Electrical machine comprising an inductive transformer device according to the preceding claim and / or a secondary device (1 ) according to any one of claims 1 to 8.

11. Motor vehicle comprising an inductive transformer device according to claim 9 and / or an electric machine according to the preceding claim and / or a secondary device (1) according to any one of claims 1 to 8.

Images