Motor

Abstract

The invention relates to an electric machine (50) having a rotor (10) which is rotatably mounted relative to a stator (40) and which has at least one heat exchange element (16) which is provided for dissipating heat generated during operation of the electric machine (50), and to a corresponding heat exchange element (16).

Description

Technical Field

[0001] The present invention relates to an electric machine having a rotor rotatably supported relative to a stator, the rotor having at least one heat exchange element arranged between two adjacent windings of the rotor, the heat exchange element being provided for dissipating heat generated during operation of the electric machine. Background Art

[0002] Electric machines can be used as work machines for electrically driven vehicles (such as electric vehicles and hybrid vehicles). Here, various types of electric machines can be used. Electric machines generally have a stator supported fixedly or non-rotatably relative to each other and a rotor supported movably (in particular rotatably) relative to the stator.

[0003] In an electrically excited electric machine, the active components have, for example, a magnetic field generating system in the form of energizable windings, which are held by a core to generate magnetic flux. During operation of the electric machine, such windings may heat up, and as a result, local heat zones or hot spots may be generated due to non-uniform temperature distribution in the windings. Since the heating of the electric machine has a negative impact on efficiency and continuous power, some solutions for cooling the electric machine are known, which can, for example, cool the rotor by means of rotor hollow shaft cooling and / or by end-side cooling at the end sides using a cooling fluid. Summary of the Invention

[0004] Against this background, the object of the present invention is to improve the electric machine, in particular with regard to its thermal performance. In particular, the structure of the rotor of the electric machine should be improved such that an improved heat distribution inside the rotor is achieved during operation.

[0005] This object is achieved by an electric machine having the features of claim 1 and a heat exchange element having the features of claim 9. The dependent claims relate to advantageous refinements of the present invention.

[0006] According to a first aspect, there is provided an electric machine having a rotor rotatably supported relative to a stator, the rotor having at least one heat exchange element arranged between two adjacent windings of the rotor, the heat exchange element being provided for conducting heat generated during operation of the electric machine to at least one end side of the rotor. The heat exchange element is in particular provided for transferring the waste heat absorbed in the winding region towards one or both end sides of the rotor or the electric machine and transferring the waste heat to a radiator of the rotor or the electric machine there for dissipation. Thereby, cooling or improved heat distribution in the rotor can be achieved, thereby improving the efficiency and / or continuous power of the electric machine.

[0007] For example, the electric machine can be used as an electric traction machine for an electrically driven motor vehicle. The electric machine is in particular designed as an electrically excited synchronous motor (SSM) or asynchronous motor (ASM) here and can have a fixedly supported stator and a rotor supported movably (in particular rotatably) relative to the stator.

[0008] The rotor generally has a rotor core arranged on a rotor shaft, which rotor core can be constituted, for example, by a rotor punching set composed of axially stacked thin iron sheets. In addition, the rotor has conductive windings, which are configured to generate or excite a magnetic flux for current conduction. For example, in an electrically excited synchronous machine, the windings can be configured as energizable field coils. The field coils can include, for example, rod-shaped conductors or formed rods, which are arranged in the slots of the rotor core or on its outer peripheral surface, or the coil can include winding wires wound around the magnetic poles of the rotor core.

[0009] To cool the rotor, the rotor shaft can be configured to be flowed through by a fluid and can be flowed through by a cooling medium. The cooling medium can be obtained, for example, from a coolant circuit or a lubricating oil circuit and is introduced into the rotor shaft through a hollow spray gun. The rotor shaft can have at least one outlet or outlet opening, which are configured to discharge the coolant from the hollow rotor shaft to the end side of the rotor and / or the end side elements arranged there. This distribution of the fluid or the cooling medium on the rotor end side or the end side elements can be achieved or promoted by the centrifugal force generated during rotor operation. Thereby, a uniform distribution of the cooling fluid can be achieved on the rotor end side, which can in turn be used for end side heat transfer.

[0010] The at least one heat exchange element is arranged on a slot lining element located between two windings of the rotor. The slot lining element is particularly provided as a sealing component for the potting material of the rotor, and / or can be, for example, a plastic element, which is arranged or can be arranged between two adjacent windings to achieve their insulation and / or spacing. By arranging the heat exchange element on such a slot lining element, the heat exchange element can be simply arranged between two adjacent windings or in the gap formed by them, so as to achieve a sufficient spacing between the heat exchange element and the windings and ensure the electrical insulation between the heat exchange element and the windings.

[0011] The heat exchange element is integrally formed on the slot lining element. The heat exchange element can be connected to the slot lining element, in particular, by an injection molding process, a spraying process or a casting process, or the slot lining element can be injection molded or cast onto a particularly pre-prepared heat exchange element. Thereby, a combination of two rotor components can be provided, so that the heat exchange element can be easily placed between the respective windings by means of the slot lining element, in order to reduce the assembly time. Here, the heat exchange element can have at least one formed profile portion to achieve or promote a form-fitting connection between the heat exchange element and the slot lining element.

[0012] The present invention is especially based on the concept of avoiding overheating or exceeding especially a predetermined maximum temperature limit value by providing at least one heat exchange element which is arranged to conduct away the (waste) heat generated during the operation of the rotor or the winding from the winding arranged especially adjacent to the heat exchange element and conduct it to at least one end side of the rotor serving as a radiator.

[0013] According to another aspect, a heat exchange element is proposed which is arranged for use in the electric machine described herein. The heat exchange element is especially constructed as solid and can be rod-shaped and / or laterally invariant here, or have a geometric structure variation, such as at least one thickening and / or narrowing and / or a wavy or meandering course, especially in its longitudinal extension. In addition, the heat exchange element can have, for example, at least one profiled section or profiled geometry, and / or be made of or have a material with a high thermal conductivity to achieve good heat transfer or transmission. Here, the heat exchange element can have a high thermal conductivity so that the temperature distribution in the rotor can be homogenized and / or local hot spots can be avoided.

[0014] By establishing a heat connection between the winding and at least one end side of the rotor by means of the heat exchange element, the heat generated during operation can be conducted away and removed from the rotor system. Thereby, the core temperature of the rotor or the electric machine can be reduced, and thus the achievable continuous torque of the electric machine can be increased.

[0015] In one embodiment, the at least one heat exchange element is thermally connected to at least one end side element of the rotor. Here, the rotor especially has at least substantially disk-shaped end side elements on its two end sides respectively, which abut against the winding heads of the rotor winding and / or can be thermally connected to them. Here, one or both end sides or end side elements of the rotor can be flowed through by a cooling medium in order to dissipate heat from the end side or the end side element. The cooling medium can be obtained, for example, from a coolant circuit or a lubricant circuit in order to achieve simple but effective heat dissipation from the rotor end side to the coolant circuit in terms of structure or manufacturing technology.

[0016] In one embodiment, the at least one heat exchange element is partially received in the end side element. Here, the end side element can have at least one groove or hole in which the at least one heat exchange element can be partially (especially form-fittingly) received to promote heat transfer between the heat exchange element and the end side element. Here, especially one or both end regions of the heat exchange element are received in the end side element such that the heat exchange element does not protrude from the end side element in order to avoid especially eddy current losses during the rotation of the rotor caused by the coolant.

[0017] In one embodiment, the at least one heat exchange element ends flush with the outer side of the end-side element. Here, the end face of the heat exchange element can be configured to match the geometry of the end-side element to form as uniform a surface of the end-side element as possible that can be flowed over, thereby promoting heat transfer by the coolant. In addition, in such a solution, waste heat can be directly transferred thermally to the coolant on the end face of the heat exchange element. Overall, a (particularly uniform) surface can thus be provided for the end-side element, so that the coolant can achieve a uniform fluid flow on the surface of the end-side element to achieve uniform heat transfer.

[0018] In one embodiment, the at least one heat exchange element extends between two end-side elements of the electric machine. Thereby, uniform heat transfer can be achieved axially from the rotor winding to the end-side or the end-side element. Since hot spots or thermal zones typically occur in the axial middle region of the winding or the rotor, effective heat conduction to both ends of the rotor can be achieved in order to reduce the internal temperature of the rotor and thus extend the service life of the rotor.

[0019] In one embodiment, the at least one heat exchange element is potted in the rotor of the electric machine together with the slot liner element. Here, the at least one heat exchange element is particularly placed between two adjacent rotor windings by means of the slot liner element, or before the rotor or the rotor core is potted (particularly with plastic or potting material), such a slot liner element with a heat exchange element is arranged in each gap between adjacent rotor windings in particular. By means of the potting material, permanent electrical insulation of the heat exchange element relative to the conductive components of the rotor can be achieved. In other embodiments, the heat exchange element itself (i.e., without the slot liner element) can be arranged in the gap and potted there.

[0020] In one embodiment, the heat exchange element is arranged uniformly spaced apart from the adjacent windings by means of the slot liner element (particularly over its entire axial extent). Thereby, particularly axially uniform heat transfer from two adjacent windings can be achieved, and sufficient spacing between the heat exchange element and the two windings can also be achieved to ensure electrical insulation of the heat exchange element.

[0021] In one embodiment, the heat exchange element comprises aluminum and / or other suitable materials with high thermal conductivity. Here, the at least one heat exchange element can in particular have or be made of a material with good heat conduction properties in order to achieve heat transfer from the particularly axial middle region to the end-side cooling surface or the end-side element, thereby reducing the core temperature of the rotor.

[0022] According to another aspect, a motor vehicle is proposed which has at least one electric machine as described herein. The above embodiments and advantages correspondingly apply to a motor vehicle having such an electric machine. Description of the Drawings

[0023] Other features of the invention emerge from the claims, the drawings and the description of the drawings. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned and / or only shown in the drawings in the description of the drawings, can be used not only in the combinations given respectively, but also in other combinations or individually. Other advantages and application possibilities of the invention emerge from the following description in conjunction with the drawings.

[0024] Figure 1 A diagrammatic sectional view shows a view of an electric machine according to an exemplary embodiment of the invention; and

[0025] Figure 2 A three - dimensional schematic partial view shows a part of an electric machine according to an exemplary embodiment of the invention. Detailed Description

[0026] Figure 1 A schematic view shows a sectional view of an electric machine 50 along the rotational axis 51 of the electric machine 50 according to an exemplary embodiment.

[0027] The electric machine 50 has a rotor 10 rotatably supported relative to a stator 40 (only schematically shown), wherein the rotor 10 has a rotor shaft 11 through which fluid flows here and a rotor core 12 arranged non - rotatably around the rotor shaft 11. Shown on the rotor core 12 are energizable windings 13, here in the form of field coils, wherein a plurality of windings 13 are arranged uniformly spaced apart from each other in the circumferential direction of the rotor 10. On the end sides 14 of the rotor 10, there is respectively arranged an end - side element 15 which closes the rotor interior space relative to the interior space 17 of the electric machine 10.

[0028] In the gaps formed between two adjacent windings 13 of the rotor 10, there is respectively arranged at least one heat - exchange element 16 which is arranged to conduct the heat generated during the operation of the electric machine 10 (especially in the windings 13) to at least one end side 14 of the rotor 10. Here, the heat - exchange element 16 is arranged on a slot - lining element 18 located in the gap in the shown embodiment. By means of the heat output achieved through the at least one heat - exchange element 16, the temperature distribution in the rotor can be made uniform and / or local hot spots can be avoided, so as to avoid, for example, a reduction in power due to overheating of the rotor components.

[0029] In order to achieve uniform heat transfer to the two end sides, the heat exchange element 16 extends between the two end side elements 15 of the rotor 10 and is thermally connected to the end side element 15 (in particular by a form-fitting connection). In the illustrated embodiment, the heat exchange element 16 is partially received in the end side element 15 in the end region of one of its end sides and is flush with the outer side of the end side element 15 facing the interior space 17 of the electric machine 50. Thereby, the eddy current losses on the outer side of the rotor 10 or the end side element 15 can be reduced.

[0030] In Figure 2 a three-dimensional schematic cross-sectional view shows a Figure 1 partial view of the electric machine 50 or its rotor 10 according to the invention. A part of the rotor core 12 of the rotor 10 of the electric machine 50 and the windings 13a and 13b arranged thereon are shown.

[0031] A slot liner element 18 is arranged in the gap formed between the windings 13a and 13b, and this slot liner element can be used as a sealing component for the potting material of the rotor 10. The heat exchange element 16 is integrally formed on the slot liner element 18, or the heat exchange element 16 is at least partially surrounded by the slot liner element 18. This can be achieved, for example, by injection molding or casting the heat exchange element 16 by means of the geometry of the slot liner element 18.

[0032] The heat exchange element 16 is substantially rod-shaped and has profiling portions 21 on opposite sides in the illustrated embodiment, and these profiling portions are used to achieve the connection between the heat exchange element 16 and the slot liner element 18 that at least partially surrounds the heat exchange element. The slot liner element 18 is arranged on the heat exchange element 16 particularly on the radially outer and inner sides relative to the rotor 10, thereby keeping the region of the heat exchange element 16 facing the winding 13 free in order to promote heat transfer between the winding 13 and the heat exchange element 16.

[0033] In some embodiments, the at least one heat exchange element 16 is potted together with the slot liner element 18 in the rotor of the electric machine, or is connected to the rotor 10 or the rotor core 12 particularly permanently by means of a potting material (not shown here), thereby enabling electrical insulation of the heat exchange element 16 from the conductive components of the rotor 10.

[0034] The slot lining element 18 has two engagement wings 19 at its radially outer end, by means of which the slot lining element can be positioned on the rotor core 12. Thereby, the central region 20 of the slot lining element 18 (on which the heat exchange element 16 is arranged) can be arranged at a uniform distance from the adjacent windings 13a and 13b. By the uniform spacing of the heat exchange element 16 from the windings 13a, 13b thus achieved (especially within the axial extent of the heat exchange element 16), a uniform heat output from the windings 13 to the end side 14 or the end side element 15 can be achieved. Thereby, the core temperature of the rotor 10 can be reduced, and thus the achievable continuous torque of the electric machine 50 can be increased.

[0035] List of reference numerals:

[0036] 10 Rotor

[0037] 11 Rotor shaft

[0038] 12 Rotor core

[0039] 13, 13a, 13b Windings

[0040] 14 End side

[0041] 15 End side element

[0042] 16 Heat exchange element

[0043] 17 Internal space of the electric machine

[0044] 18 Slot lining element

[0045] 19 Engagement wing

[0046] 20 Central region

[0047] 40 Stator

[0048] 50 Electric machine

[0049] 51 Axis of rotation.

Claims

1. A motor (50) having a rotor (10) rotatably supported relative to a stator (40), the rotor having at least one heat exchange element (16) arranged between two adjacent windings (13) of the rotor (10), the heat exchange element being configured to conduct heat generated during operation of the motor (50) to at least one end side (14) of the rotor (10), wherein, The heat exchange element (16) is arranged on the slot liner element (18) located between the two windings (13) of the rotor (10), and the heat exchange element (16) is integrally formed on the slot liner element (18).

2. The electric machine (50) according to claim 1, wherein, The heat exchange element (16) is thermally connected to at least one end-side element (15) of the rotor (10).

3. The electric machine (50) according to the preceding claim, wherein, The heat exchange element (16) is partially received in the end-side element (15).

4. The electric machine (50) according to any one of the preceding two claims, wherein, The heat exchange element (16) ends flush with the outer side surface of the end-side element (15).

5. The electric machine (50) according to any one of the preceding three claims, wherein, The heat exchange element (16) extends between the two end-side elements (15) of the rotor (10).

6. The electric machine (50) according to any one of the preceding claims, wherein, The at least one heat exchange element (16) is potted in the rotor (10) together with the slot liner element (16).

7. The electric machine (50) according to any one of the preceding three claims, wherein, The heat exchange element (16) is arranged at a uniform distance from the adjacent windings (13) by means of the slot liner element (16).

8. The electric machine (50) according to any one of the preceding claims, wherein, The heat exchange element (16) contains aluminum.

9. A heat exchange element (16), the heat exchange element being provided for use in an electric machine (50) constructed according to at least one of the preceding claims.

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