Secondary device for an inductive excitation device

Abstract

Secondary device (2) for an inductive excitation device (1) for a separately excited electrical machine, in particular for a motor vehicle, wherein the secondary device (2) comprises a control device (4) designed for rectifying an electrical signal transmitted to the secondary device (2), in particular a rectifier device (5), and a cooling device (7) associated with the control device (4), wherein the cooling device (7) comprises a base body (9) which has a double-T-shaped cross-section in at least one section.

Description

[0001] The invention relates to a secondary device for an inductive excitation device for a separately excited electric machine, in particular for a motor vehicle, wherein the secondary device comprises a control device designed for rectifying an electrical signal transmitted to the secondary device, in particular a rectifier device, and a cooling device associated with the control device.

[0002] 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., from the primary to the secondary side, in order to subsequently supply it to the rotor windings of the electrical machine.

[0003] 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.

[0004] 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.

[0005] The invention is based on the objective of providing an improved secondary device for an inductive excitation device for a separately excited electrical machine.

[0006] The problem is solved by a secondary device having the features of claim 1. Advantageous embodiments are the subject of the dependent claims.

[0007] As described, the invention relates to a secondary device for an inductive excitation device for a separately excited electric machine, specifically for a motor vehicle. The electric machine is, for example, designed as a drive unit for the motor vehicle, for instance as a component of an electric axle drive. The secondary device includes a control device configured to rectify an electrical signal transmitted to the secondary device. For example, the control device is configured as a rectifier device or includes such a rectifier device, specifically with rectifier diodes. The control device is associated with a cooling device or is arranged on such a cooling device.The cooling system includes, for example, a heat sink on which a circuit board of the control unit, specifically an "IMS board," is mounted. Alternatively, the circuit board can be of conventional design, such as a printed circuit board (PCB), a single-sided printed circuit board, or a multilayer board. In particular, the circuit board can be designed with additional integrated heat transfer elements between the electronic components, such as rectifier diodes, and the heat sink.

[0008] The invention is based on the finding that the cooling device has a base body which, in at least one section, has a double-T-shaped cross-section. The longitudinal axis of the base body of the cooling device, which can also be referred to as a heat sink, extends, in particular, in the axial direction with respect to an axis of rotation of the rotor shaft of the electric machine. By forming the section with a double-T-shaped cross-section, at least in a core area of ​​the cooling device, various mounting surfaces for different electronic components of the control device are created. These also extend parallel to the axis of rotation, or their surface normal is perpendicular to the axis of rotation.

[0009] This allows for greater design freedom, as the electronic components of the control unit do not need to be arranged perpendicular to the axis of rotation on a circular circuit board. Instead, the cooling unit can be flexibly scaled in the axial direction. Furthermore, the double-T-shaped cross-section of the cooling unit's base offers advantages for assembly, particularly for creating a blind connection between rotor-side terminals and control unit-side or secondary unit-side contact elements. This will be described in more detail below.

[0010] The secondary device can be further developed, for example, such that at least one section is arranged as a central section in the axial direction with respect to an axis of rotation of the secondary device between two contact sections. In an assembled state of the secondary device, the contact sections make contact with an inner wall of the rotor shaft, and a gap is formed between the central section and the inner wall. Viewed in the axial direction, the central section is thus located between the two contact sections. In an assembled state of the secondary device, in which the cooling device is arranged inside the rotor shaft, the contact sections make contact with the inner wall of the rotor shaft. The contact sections thus enable the formation of a direct heat path from the base body of the cooling device to the rotor shaft, in particular without having to bridge an intermediate gap.This allows heat generated during the operation of the control device to be dissipated in a targeted manner via the contact sections. As described, a gap is formed around the cooling unit in the central section, so that there is no contact between the cooling unit and the rotor shaft.

[0011] The described central section can specifically have four mounting surfaces arranged around the axis of rotation, on which electronic components of the control device are arranged. Reference is made here to those mounting surfaces whose surface normal is perpendicular to the axis of rotation. As described, the central section connects the two contact sections where the secondary device rests flat against the inner wall of the rotor shaft. The contact sections may, in turn, be interrupted in the circumferential direction.

[0012] The double-T cross-section can generally be divided into two transverse webs or sides, which are connected by a connecting web. For example, when the base body is designed with a double-T cross-section, two opposing connecting webs are formed at the connecting web. In these areas, at least the contact section facing away from the secondary ferrite and projecting into the rotor shaft with its free end can be interrupted or exposed. For example, the contact sections on the transverse sides of the double-T shape can be designed as circular segments connected by the connecting web.

[0013] This means that the electronic components of the control device can be arranged in any configuration on the various mounting surfaces of the central section. For example, three of the mounting surfaces can be used for rectifier elements, and one for a protective circuit. Heat-conducting elements can be attached to the described double-T-shaped base of the cooling device to form the contact sections. These elements can be, for example, radially opposite each other in the shape of circular segments and connected by a connecting bridge. The central section can also be connected to or integrally formed with such heat-conducting elements.

[0014] The secondary device may further be provided with two rectifier elements, in particular rectifier diodes, arranged on one of the two mounting surfaces furthest from the axis of rotation, and a protective circuit arranged on the opposite mounting surface. In principle, the dimensions of the various sections of the double-T shape of the base body are arbitrarily adjustable, selectable, or definable. It is advantageous for the transverse sides described to be longer than the connecting sides described. Since the double-T shape must be accommodated within the rotor shaft, the connecting sides must be located closer to the axis of rotation than the transverse sides.

[0015] In the described embodiment, two of the rectifier elements, specifically rectifier diodes, can be arranged on one of the mounting surfaces formed on a transverse side, and the protective circuit can be arranged on the mounting surface opposite each other with respect to the axis of rotation, which is therefore also located on a transverse side. The axis of rotation runs, for example, through the center of the double-T shape. This design allows, in particular, the arrangement of the electronic components without bridges on the mounting surfaces. In a specific embodiment, two rectifier elements can be provided on one of the mounting surfaces located on the transverse side, and one rectifier element can be arranged on each of the mounting surfaces located on the connecting sides.Accordingly, the protective circuit is located on the remaining mounting surface, i.e., on the transverse side opposite the transverse side with respect to the axis of rotation on which the two rectifier elements are arranged.

[0016] Electronic components can be connected, in particular, by perforating the mounting surfaces and routing corresponding connecting leads through them. A printed circuit board (PCB), such as an IMS PCB, can be mounted on each mounting surface to accommodate the electronic components. The base of the cooling device can be made of or comprise a metal, such as aluminum. The arrangement of the electronic components on the base thus enables heat conduction through the base. Since the base is connected to the rotor shaft via the contact sections, the heat is dissipated directly into the rotor shaft.

[0017] Alternatively, the secondary device can be provided with two rectifier elements, in particular rectifier diodes, arranged on at least one of the two mounting surfaces further away from the axis of rotation, and a protective circuit arranged on at least one mounting surface closer to the axis of rotation, in particular distributed across both mounting surfaces closer to the axis of rotation. In this embodiment, the rectifier elements, i.e., for example, the rectifier diodes, are each arranged on the mounting surfaces formed on the transverse sides of the double-T shape.

[0018] Accordingly, the protection circuit is distributed across the remaining mounting surfaces, i.e., those located on the connection sides. Advantageously, since the electronic components belonging to the protection circuit are typically lower in height than the rectifier elements, especially rectifier diodes, the connection sides or the connecting bridge of the double-T shape can be made thicker without the connecting elements coming into contact with the electronic components when the secondary device is assembled. This also allows the thickness of the base body to be increased, thereby improving its thermal conductivity and heat capacity.

[0019] As previously described, the secondary device described herein is intended to improve the installation of an inductive excitation device in an electric machine. In one embodiment of the secondary device, it can be provided that the secondary device for blind contacting has at least one contact element, specifically exactly two contact elements, which are axially oriented and designed to receive a terminal element connected to a rotor winding of the electric machine and oriented in the direction of the contact element. Advantageously, the secondary device can thus be installed independently of the manufacturing of the rotor, specifically the rotor winding of the electric machine.

[0020] Assembly processes that require exposure to relatively high temperatures or relatively large temperature fluctuations do not necessarily affect the control device, particularly its electronic components. For example, the rotor may already be fully manufactured, especially the rotor's laminated core may already be mounted on the rotor shaft, which typically requires controlled cooling of the rotor shaft and controlled heating of the laminated core laminations. Furthermore, the rotor winding may be potted with a potting compound and cured, which also typically requires controlled temperature control. Only after the rotor's manufacture is complete can the secondary control device be installed in the rotor, namely by means of a blind connection between the at least one contact element and the at least one corresponding terminal element.

[0021] The described embodiment can be further developed such that the contact elements are formed circumferentially on the circumferential position of the mounting surfaces located closer to the axis of rotation. The secondary device therefore has the contact elements at the circumferential positions of the mounting surfaces that are located closer to the axis of rotation. This makes it possible for the connecting elements, which are connected to the rotor winding of the electric machine and which are arranged in the rotor shaft, to be guided in the circumferential area of ​​the mounting surfaces that are located closer to the axis of rotation during the assembly of the secondary device.

[0022] In other words, during the assembly of the secondary device, the connection elements pass by these mounting surfaces and the electronic components arranged on them. The connection elements are thus located in the U-shaped sections of the double-T shape. These connection elements can, for example, be designed as contact blades and project radially into the rotor shaft. The electronic components of the secondary device, which are located on the mounting surfaces closer to the axis of rotation, can therefore move radially past the connection elements. In particular, when combined with the arrangement of the protection circuitry in these circumferential positions or on these mounting surfaces, space utilization is especially advantageous, as these components are typically less tall than other electronic components.

[0023] In a further development of the secondary device, a protective circuit may be provided in parallel with the contact elements of the secondary device that are intended for contacting the rotor winding. In other words, the protective circuit is provided as a parallel connection to the contact elements of the secondary device that accommodate the connection elements connected to the rotor winding.

[0024] In addition to the secondary device, the invention relates to an inductive excitation device comprising a primary device and a previously described secondary device. Furthermore, the invention relates to a drive arrangement comprising such an inductive excitation device and / or a previously described secondary device. Finally, the invention relates to a motor vehicle comprising a previously described drive arrangement and / or an inductive excitation device and / or a previously described secondary device.

[0025] All the advantages, details and features described in relation to the secondary device are fully transferable to the inductive excitation device, the drive arrangement and the motor vehicle.

[0026] The invention is explained below with reference to exemplary embodiments and the figures. The figures are schematic representations and show: Fig. 1. A schematic representation of an inductive excitation device with a secondary device in perspective view; Fig. 2 a longitudinal section along the axis of rotation of the secondary device; Fig. 3 a perspective view of the inductive excitation device of Fig. 1 in a partially separated state; and Fig. 4 A side view of the inductive excitation device in a state mounted in a rotor shaft.

[0027] Fig. Figure 1 shows a schematic diagram of an inductive excitation device 1 with a secondary device 2 for a separately excited electrical machine, which is not shown in detail, for example, a drive unit for a motor vehicle. In addition to the secondary device 2, the inductive excitation device 1 has a primary device 3. The secondary device 2 and the primary device 3 are designed in a manner known per se and include appropriate ferrites, coils, and the like, and are configured to inductively transmit energy, in particular electrical signals, for example, an electric current, from the primary device 3 to the secondary device 2.

[0028] The secondary device 2 includes a control device 4, which is designed, among other things, to rectify the electrical signal transmitted from the primary device 3 to the secondary device 2. Specifically, the control device 4 therefore includes a rectifier device 5, which comprises rectifier elements 6, for example, rectifier diodes. Furthermore, the secondary device 2 includes a cooling device 7, which is associated with the control device 4 and / or cools electronic components, specifically the rectifier elements 6 and / or a protective circuit 8 (see Figure 1). Fig. 4) are arranged on the cooling device 7. The protective circuit 8 is designed, for example, to dissipate overvoltages or, in fault conditions, to protect the control device 4 or the inductive excitation device 1 from damage.

[0029] The cooling device 7 has a base body 9 which has a double-T-shaped cross-section (see figure). Fig. 1) The double-T-shaped cross-section is further illustrated in a detailed diagram in Fig. Figure 1 shows the double-T-shaped cross-section having two transverse sides 10, 11, which are connected to each other via a connecting web 12, on which connecting web 12 connecting sides 13, 14 are arranged. This results in four arrangement surfaces 15-18 being formed on the base body 9, with arrangement surfaces 15, 16 being located on the transverse sides 10, 11 and arrangement surfaces 17, 18 being located on the connecting sides 13, 14. The transverse sides 10, 11, and thus the arrangement surfaces 15, 16, are located further away from an axis of rotation 19 than the connecting sides 13, 14, and thus the arrangement surfaces 17, 18. The axis of rotation 19 runs, in particular, through the center of the double-T shape (see Figure 1). Fig. 2, Fig. 4).

[0030] The electronic components of the control device 4 are arranged on the mounting surfaces 15-18. In particular, the electronic components are arranged on printed circuit boards, for example, so-called "IMS printed circuit boards," which in turn are arranged on the mounting surfaces 15-18. The described base body 9 of the cooling device 7 is formed at least in a central section 20, which is arranged between two contact sections 21, 22. The contact sections 21, 22 are mechanically and thermally coupled to the central section 20, for example, by joining them or forming them as a single unit. This results in a main heat conduction path through the base body 9, in which the heat from the electronic components is introduced into the base body 9 through the mounting surfaces 15-18 and conducted axially to the contact sections 21, 22, which, in the assembled state, are in mechanical contact with a rotor shaft 23 (see Figure 1). Fig. 4) stand.

[0031] In the exemplary embodiment shown, on the arrangement surface 15, which extends on the transverse side 10, for example in Fig. 1, Fig. 3 above and in Fig. Figure 4 below shows two rectifier elements 6 arranged. It is further shown that one rectifier element 6 is arranged on each of the mounting surfaces 16, 17, which extend along the connecting sides 13, 14. Finally, the protective circuit 8 is arranged on the mounting surface 18, which is located on the transverse side 11 of the double-T shape. Alternatively, it is also possible that the protective circuit 8 is divided between the mounting surfaces 16, 17, and that two rectifier elements 6 are located on each of the mounting surfaces 15 and 18. The description is transferable accordingly.

[0032] It follows that the arrangement surfaces 16, 17 are located closer to the axis of rotation 19 than the arrangement surfaces 15, 18. Furthermore, the contact sections 21, 22 are interrupted in the circumferential regions where the arrangement surfaces 16, 17 are formed. The contact sections 21, 22 form, for example, circular segments that are interrupted at least in the region of the arrangement surfaces 16, 17 and are connected via the connecting web 12. The contact section 21 is formed, for example, by four circular segments and the contact section 22, for example, by two circular segments. This makes it possible for connecting elements 24, which are arranged, for example, in the rotor shaft 23 and project radially into the rotor shaft 23, to be guided through the gaps that result adjacent to the arrangement surfaces 16, 17 in the U-shaped areas of the double-T shape.In other words, the secondary device 2 can be inserted axially into the rotor shaft 23 along the axis of rotation 19 of the rotor shaft 23. The connecting elements 24 engage in the recesses of the contact sections 21, 22 and are guided parallel to the mounting surfaces 16, 17. Therefore, the secondary device 2 can be inserted axially into the rotor shaft 23 between the connecting elements 24.

[0033] The secondary device 2 can therefore be blindly mounted in the rotor shaft 23. As, for example, in Fig.As shown in Figures 2-4, the secondary device 2 has contact elements 25 that are open in the axial direction and are designed to receive axially oriented connection elements 24, for example, axially open bushings. This allows the secondary device 2 to be axially inserted into the rotor shaft 23, particularly after the rotor of the electric machine has been completed. The connection elements 24, which project radially into the rotor shaft 23, are therefore axially received in the contact elements 25.

[0034] By arranging the contact elements 25 in the circumferential positions of the mounting surfaces 16, 17, i.e., the mounting surfaces 16, 17 located closer to the axis of rotation 19, the installation space is utilized more efficiently, as the connection elements 24 can be arranged there, or, during assembly, the mounting surfaces 16, 17 can be guided relative to the connection elements 24. If the protective circuit 8 is arranged on the mounting surfaces 16, 17, the installation space can be utilized more efficiently, since the electronic components of the protective circuit 8 are typically less tall than the rectifier elements 6.

[0035] It is further shown that the individual arrangement surfaces 15-18 can be pierced by corresponding conductor elements 26 to establish contact between the electronic components or to the contact elements 25. Advantageously, this allows for particularly efficient routing of the control device 4. In particular, bridges and the like can be dispensed with.

[0036] As previously described, the secondary device 2 or the inductive excitation device 1 can be part of a drive arrangement for a motor vehicle. Such a motor vehicle can have such a drive arrangement or the inductive excitation device 1 or a secondary device 2 as described. All advantages, details, and features described with respect to the secondary device 2 and the inductive excitation device 1 are fully transferable to the drive arrangement and the motor vehicle. All advantages, details, and features described in the individual embodiments can be combined, interchanged, and transferred to one another as desired. Reference sign 1 inductive excitation device 2 Secondary facility 3 Primary facility 4 Control unit 5 Rectifier unit 6 Rectifier element 7 Cooling unit 8 Protection circuit 9 basic shapes 10, 11 side 12 Connecting bridge 13, 14 Connection page 15-18 layout area 19 axis of rotation 20 Middle section 21, 22 Contact section 23 Rotor shaft 24 connection element 25 contact element 26 conductor element

Claims

[1] Secondary device (2) for an inductive excitation device (1) for a separately excited electrical machine, in particular for a motor vehicle, wherein the secondary device (2) comprises a control device (4) designed for rectifying an electrical signal transmitted to the secondary device (2), in particular a rectifier device (5), and a cooling device (7) associated with the control device (4), characterized by , that the cooling device (7) has a base body (9) which has a double-T-shaped cross-section in at least one section. [2] Secondary device (2) according to claim 1, characterized by, that the at least one section is arranged as a central section (20) in the axial direction with respect to an axis of rotation (19) of the secondary device (2) between two contact sections (21, 22), wherein in an assembled state of the secondary device (2) the contact sections (21, 22) contact an inner wall of the rotor shaft (23) and a gap is formed between the central section (20) and the inner wall. [3] Secondary device (2) according to claim 1 or 2, characterized by , that the central section (20) has four arrangement surfaces (15-18) arranged around the axis of rotation (19), on which electronic components of the control device (4) are arranged. [4] Secondary device (2) according to claim 3, characterized by, that on one of the two arrangement surfaces (15, 18) further away from the axis of rotation (19) two rectifier elements (6), in particular rectifier diodes, are arranged and on the opposite arrangement surface (15, 18) a protection circuit (8) is arranged. [5] Secondary device (2) according to claim 3, characterized by , that on at least one of the two arrangement surfaces (15, 18) located further away from the axis of rotation (19) two rectifier elements (6), in particular rectifier diodes, are arranged and a protection circuit (8) is arranged on at least one arrangement surface (16, 17) located closer to the axis of rotation (19), in particular distributed over both arrangement surfaces (16, 17) located closer to the axis of rotation (19). [6] Secondary device (2) according to any one of the preceding claims, characterized by, that the secondary device (2) for blind contacting has at least one contact element (25) which is aligned in the axial direction and is designed to receive a terminal element (24) connected to a rotor winding of the electrical machine and aligned in the direction of the contact element (25). [7] Secondary device (2) according to claim 6, characterized by , that the contact elements (25) are formed in the circumferential direction on the circumferential position of the arrangement surfaces (16, 17) which are arranged closer to the axis of rotation (19). [8] Secondary device (2) according to any one of the preceding claims, characterized by , that a protective circuit (8) is connected in parallel to the contact elements (25) of the secondary device (2) which are intended for contact with the rotor winding. [9] Inductive excitation device (1) comprising a primary device (3) and a secondary device (2) according to any of the preceding claims. [10] Drive arrangement comprising an inductive excitation device (1) according to the preceding claim and / or a secondary device (2) according to any one of claims 1 to 8. [11] Motor vehicle comprising a drive arrangement according to the preceding claim and / or an inductive excitation device (1) according to claim 9 and / or a secondary device (2) according to any one of claims 1 to 8.

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