Rotor for an electrical machine, in particular of a motor vehicle, and motor vehicle

Abstract

The invention relates to a rotor (1) for an electrical machine, with at least one winding (2) for generating a magnetic field, with a laminated core (4) carrying the winding (2), which laminated core has at least one groove (6) in which longitudinal regions (L) of the winding (2) are received, and with at least one closure element (10) formed separately from the winding (2) and separately from the laminated core (4), by means of which the groove (6) is at least partially closed to the outside in the radial direction (5) of the rotor (1), wherein the closure element (10) is formed from a plastic (K) in which an insert (11) formed from a material different from the plastic (K) is embedded.

Description

[0001] The invention relates to a rotor for an electrical machine, in particular of a motor vehicle, according to the preamble of patent claim 1. Furthermore, the invention relates to a motor vehicle with at least one such electrical machine.

[0002] WO 2018 / 137999 A1 discloses a component of an electrical machine, wherein the component has a plurality of slots extending over an axial extent of the component. The slots accommodate sections of windings formed from wires, wherein the slots filled with the winding sections are each closed by a cover slide. Furthermore, WO 2022 / 023043 A1 discloses a cover slide of a dynamoelectric machine. Furthermore, WO 2023 / 110275 A1 discloses a cover slide for a salient pole rotor of an electrical machine for closing a slot formed between two adjacent salient poles of the salient pole rotor.

[0003] The object of the present invention is to provide a rotor for an electrical machine and a motor vehicle with at least one such electrical machine, so that at least one groove of a laminated core of the rotor can be closed in a particularly advantageous manner.

[0004] This object is achieved according to the invention by a rotor having the features of patent claim 1 and by a motor vehicle having the features of patent claim 10. Advantageous embodiments of the invention are the subject of the dependent claims.

[0005] A first aspect of the invention relates to a rotor for an electric machine, in particular of a motor vehicle. This means that the electric machine, in its fully manufactured state, has the rotor and, for example, also a stator, by means of which the rotor can be driven and is therefore rotatable about an axis of rotation relative to the stator. Furthermore, it is conceivable that the motor vehicle, also simply referred to as a vehicle and preferably designed as a motor vehicle, in particular as a passenger car, has the electric machine in its fully manufactured state and can be driven, in particular purely electrically, by means of the electric machine. In particular, the electric machine can provide drive torques for driving the motor vehicle, in particular purely electrically, via its rotor.The electrical machine is preferably designed as a high-voltage component whose electrical voltage, in particular electrical operating or nominal voltage, is preferably greater than 50 volts, in particular greater than 60 volts, and very preferably amounts to several hundred volts. The rotor has at least one winding, also referred to as the rotor winding, by means of which a magnetic field can be generated, i.e. provided, in particular for driving the rotor. Furthermore, the rotor has a laminated core formed separately from the winding, by which the winding is carried. This means that the winding is held on the laminated core and is thus carried by the laminated core. In particular, the winding is wound around at least a partial region of the laminated core. The laminated core has at least one slot, which is also referred to as the first slot.When reference is made above and below to the slot, this means the first slot unless otherwise stated. Length regions of the winding are accommodated in the slot, with the length regions accommodated in the slot also being referred to as first length regions. When reference is made above and below to the length regions, this means, unless otherwise stated, the first length regions of the winding accommodated in the first slot. In particular, it is conceivable for the laminated core to have a plurality of slots, namely the first slot and at least one or more further slots, with the slots, for example, being arranged one after the other and in particular at a distance from one another in the circumferential direction of the rotor and thus of the electrical machine running around the axis of rotation.In this case, for example, a tooth of the laminated core is arranged, in particular precisely, between each two slots that are directly consecutive and thus adjacent to one another in the circumferential direction of the rotor, which tooth is also referred to as a pole or salient pole or forms a pole, also referred to as a salient pole, of the electrical machine. The aforementioned winding is also referred to as the first winding. It is conceivable for the rotor to have several windings, namely the aforementioned first winding and at least one or more further windings. In this case, for example, respective length regions of the winding and / or the windings are arranged in the slots. The previous and following statements regarding the first slot can easily be transferred to the, in particular respective, second slot and vice versa.

[0006] The rotor has at least one closure element, also referred to as a cover slide, which is formed separately from the winding and the laminated core. This closure element at least partially, in particular at least predominantly, and thus at least more than half or completely, closes the slot in the radial direction of the rotor, whose axial direction runs perpendicular to the radial direction of the rotor and coincides with the axis of rotation. The closure element is also referred to as a closure wedge or slot closure wedge, although the closure element does not necessarily have to be wedge-shaped.

[0007] In order to be able to close the groove particularly advantageously, the invention provides that the closure element is made of a plastic, in which an insert made of a material different from the plastic is embedded, i.e. at least partially received. This means in particular that the closure element has a base body made of the plastic. The plastic is also referred to as the first plastic. When the plastic is mentioned above and below, this means the first plastic, unless otherwise stated. In particular, the groove is closed at least partially, in particular at least predominantly and thus at least more than half or completely, by the base body towards the outside in the radial direction of the rotor.Furthermore, the closure element has the insert, which is made of a material different from the plastic and embedded in the plastic. This makes it possible to achieve a particularly high degree of strength for the closure element, so that the groove can be securely closed and kept closed by means of the closure element, especially when the rotor rotates at very high speeds about the axis of rotation relative to the stator, and thus very high centrifugal forces act on the closure element, particularly in the radial direction of the rotor outwards. At the same time, the weight and cost of the closure element, and thus of the rotor as a whole, can be kept particularly low.

[0008] In order to achieve particularly advantageous rigidity and / or strength of the closure element, one embodiment of the invention provides for the insert to be curved inwards in the radial direction of the rotor, the axial direction of which runs perpendicular to the radial direction of the rotor, and thus towards the groove. As a result, the insert is designed to be self-reinforcing because, for example, when the rotor rotates about the axis of rotation relative to the stator, centrifugal forces act on the closure element outwards in the radial direction of the rotor. As a result, for example, the curvature of the insert is at least partially canceled out, whereby, for example, an extension of the insert, also referred to as length or width, running in the circumferential direction of the rotor around the axial direction of the rotor and thus around the axis of rotation, increases.As a result, for example, the closure element is pressed increasingly harder against the laminated core as the speed and thus the centrifugal forces increase, thus securing it more and more firmly to the laminated core. This prevents unwanted detachment of the closure element from the laminated core, particularly at high rotor speeds. This allows the slot to be securely closed by the closure element, even at very high rotor speeds. As a result, unwanted movement of the longitudinal sections out of the slot can be prevented, thus preventing unwanted disintegration of the rotor even at high speeds at which the rotor rotates or can rotate about the axis of rotation relative to the stator.

[0009] In order to achieve a particularly high strength and / or rigidity of the closure element in a particularly weight-efficient manner and thus to be able to keep the groove securely closed even at very high speeds of the rotor, it is provided in a further embodiment of the invention that the insert part is fully and thus completely embedded in the plastic, and is therefore completely surrounded by the plastic.

[0010] A further embodiment is characterized in that the closure element is designed as an injection-molded part. This means, in particular, that the aforementioned base body, which is formed from the plastic, is designed as an injection-molded part. This means that the base body is produced by injection molding, i.e. by an injection molding process, also referred to as an injection molding operation, in which the base body or the closure element is injection-molded. In other words, in a method for producing the closure element, the aforementioned injection molding process is carried out, by which or in which the base body is injection-molded and thus produced. For example, the injection molding process, also referred to as an injection molding process, is carried out using an injection molding tool.The injection molding tool has, for example, a mold, also referred to as a cavity, into which the plastic is introduced, in particular injected. The insert can be embedded in the plastic by directly inserting the insert during the injection molding process. This means, in particular, that the insert is arranged in the mold before the plastic is introduced into the mold. The plastic is then introduced into the mold while the insert is in the mold. This molds the plastic onto the insert. In other words, the insert is at least partially, in particular over its entire circumference and thus completely, overmolded with the plastic.The base body is produced by introducing, in particular injecting, the plastic into the mold. Since the insert already arranged in the mold is at least partially overmolded with the plastic during the introduction of the plastic into the mold, the insert is embedded in the plastic during the production of the base body. This allows the closure element to be manufactured in a time- and cost-effective manner.

[0011] In order to be able to securely close and keep the groove closed, particularly at high rotor speeds, a further embodiment of the invention provides for the insert to be arranged in the circumferential direction of the rotor between two wall regions of the rotor, in particular of the laminated core, which face one another in the circumferential direction of the rotor and at least partially and preferably directly delimit the groove in the circumferential direction of the rotor. The wall regions are arranged at a distance from one another in the circumferential direction of the rotor and are thus spaced apart from one another in the circumferential direction of the rotor, the circumferential direction of which extends around the axial direction of the rotor and thus around the axis of rotation.In this case, it is preferably provided that the insert extends in the circumferential direction of the rotor at least over more than half the distance, in particular at least over more than 70%, very particularly at least over more than 80% and very preferably at least over more than 90% of the distance, between the wall regions. If, for example, centrifugal forces act on the closure element when the rotor rotates about the axis of rotation relative to the stator, wherein the centrifugal forces act outwards in the radial direction of the rotor, this results, for example, in an increase in the aforementioned extension of the insert running in the circumferential direction of the rotor, also referred to as an increase in length, increase in width or increase in extension, in particular if the insert is curved inwards in the radial direction of the rotor.Due to this increase in extension, the closure element is pressed more and more strongly against the aforementioned wall areas of the rotor with increasing speed and thus with increasing centrifugal forces and is thus increasingly fixed to the laminated core, so that undesired disintegration of the rotor can be advantageously avoided.

[0012] It has proven particularly advantageous if the plastic, especially the base body, extends in the circumferential direction of the rotor over the entire distance between the wall areas and thus, for example, directly touches the wall areas. This allows the closure element to be particularly securely fixed to the laminated core, thus preventing unwanted disintegration.

[0013] The wall regions of the rotor can be wall regions of the laminated core. Furthermore, it is conceivable for the wall regions of the rotor to be wall regions of a device of the rotor that is formed separately from the laminated core, separately from the closure element, and also separately from the winding, so that the wall regions are formed by the device. For example, the device has a one-piece component, i.e., formed from a single piece, by which the wall regions are formed, so that the wall regions are wall regions of the component. Furthermore, it is conceivable for the device to have a first component and a second component, wherein the components are formed separately from one another and, for example, are connected to one another at least indirectly, in particular directly.In this case, for example, the first component forms a first of the wall regions, such that the first wall region is a wall region of the first component, and the second component forms, for example, a second of the wall regions, such that, for example, the second wall region is a wall region of the second component. For example, the component and / or the first component and / or the second component is a so-called pole shoe of the rotor. For example, the component and / or the first component and / or the second component is connected, in particular directly, to the rotor. Generally speaking, the respective wall region is thus formed separately from the closure element.

[0014] A further embodiment is characterized in that the material from which the insert is formed is a metallic material, whereby a particularly high strength and / or rigidity of the closure element can be achieved.

[0015] It has proven particularly advantageous if the metallic material is steel or a light metal alloy, such as an aluminum alloy or a titanium alloy. This ensures particularly high strength and / or rigidity of the closure element while maintaining a particularly low weight.

[0016] Finally, it has proven particularly advantageous if the material is a fiber-reinforced plastic comprising a second plastic, different from the first plastic, as a matrix, in which reinforcing fibers are embedded. Preferably, the reinforcing fibers are formed from a material different from the first plastic and the second plastic. For example, the reinforcing fibers are carbon fibers, so that the fiber-reinforced plastic can be a carbon fiber-reinforced plastic. This allows for a particularly high degree of rigidity and / or strength of the insert, and thus of the closure element as a whole, to be achieved in a particularly weight-efficient manner.

[0017] A second aspect of the invention relates to a motor vehicle, also simply referred to as a vehicle and preferably designed as a motor vehicle, in particular as a passenger car, which has at least one electric machine. The electric machine has a stator and a rotor according to the first aspect of the invention, wherein, for example, the rotor can be driven by means of the stator and is thus rotatable about an axis of rotation relative to the stator. In particular, the electric machine can provide drive torques via its rotor for driving the motor vehicle, in particular purely electrically. Advantages and advantageous embodiments of the first aspect of the invention are to be regarded as advantages and advantageous embodiments of the second aspect of the invention and vice versa.

[0018] Further details of the invention will become apparent from the following description of a preferred embodiment with the accompanying drawings. Fig. 1 shows a partial schematic cross-sectional view of a rotor for an electrical machine, in particular of a motor vehicle.

[0019] Fig. Figure 1 shows a partial schematic cross-sectional view of a rotor 1 for an electrical machine, in particular of a motor vehicle. In its fully manufactured state, the electrical machine comprises the rotor 1 and a Fig. 1 not shown stator, by means of which the rotor 1 can be driven and thereby rotated about an axis of rotation relative to the stator. The axis of rotation is in Fig. 1 not shown, but runs perpendicular to the image plane of Fig. 1. The electric machine, whose axial direction coincides with the axis of rotation, can provide drive torques via the rotor 1 for driving the motor vehicle, in particular purely electrically.

[0020] Preferably, the electric machine, whose radial direction is perpendicular to the axial direction of the electric machine and thus perpendicular to the axis of rotation, is designed as a high-voltage component.

[0021] The rotor 1, whose axial direction coincides with the axial direction of the electrical machine and thus with the axis of rotation, has at least one winding 2, by means of which a magnetic field can be generated, in particular for driving the rotor 1. Since the axial direction of the rotor 1 coincides with the axial direction of the electrical machine and thus with the axis of rotation, the axial direction of the rotor 1 is perpendicular to the image plane of Fig. 1. The axial direction of the rotor 1 is illustrated by a double arrow 3. The rotor 1, whose radial direction is perpendicular to the axial direction of the rotor 1, has a laminated core 4. The radial direction of the rotor 1 is illustrated by a double arrow 5, runs perpendicular to the axial direction of the rotor 1 and thus runs in the image plane of Fig. 1. Furthermore, the radial direction of the rotor 1 coincides with the radial direction of the electric machine. The winding 2 is supported by the laminated core 4. This means that the winding 2, which is formed separately from the laminated core 4, is held on the laminated core 4 and is thus supported by the laminated core 4. In particular, the winding 2 is wound around at least a partial area of the laminated core 4 and is thereby held on the laminated core 4.

[0022] The laminated core 4 has a plurality of grooves arranged successively and in particular spaced apart from one another in the circumferential direction of the rotor 1, which runs around the axial direction of the rotor 1 and thus around the axis of rotation, of which Fig. 1 one of the grooves is visible and is labeled 6. The circumferential direction of the rotor 1 runs in the image plane of Fig. 1, around the axial direction of the rotor 1 and is illustrated by a double arrow 7. When reference is made above and below to the axial direction, this means, unless otherwise stated, the axial direction of the rotor 1. When reference is made above and below to the radial direction, this means, unless otherwise stated, the radial direction of the rotor 1. It can be seen that lengths L of the winding 2 are accommodated in the slot 6. The slot 6 is arranged in the circumferential direction of the rotor 1 between two teeth 8 and 9 of the laminated core 4 that are directly consecutive and thus adjacent to one another in the circumferential direction of the rotor 1, so that the slot 6 is delimited on both sides in the circumferential direction of the rotor 1 and in each case directly by the teeth 8 and 9. When reference is made above and below to the circumferential direction, this means, unless otherwise stated, the circumferential direction of the rotor 1.The feature that the teeth 8 and 9 are directly consecutive in the circumferential direction and thus adjacent to one another means that no other tooth of the laminated core 4 is arranged between the teeth 8 and 9 in the circumferential direction of the rotor 1.

[0023] The rotor 1 also has at least one closure element 10 formed separately from the laminated core 4 and separately from the winding 2, by which the slot 6 is at least partially closed to the outside in the radial direction of the rotor 1. This is achieved in particular by the fact that the slot 6 is at least partially covered to the outside in the radial direction of the rotor 1 by the closure element 10 and is thereby closed.

[0024] In order to be able to close the groove 6 particularly advantageously outwards by means of the closure element 10 in the radial direction of the rotor 1, the closure element 10 is formed from a plastic K, in which, in particular precisely, an insert 11 formed from a material different from the plastic K is embedded. This means in particular that the closure element 10 has a base body 12 formed from the plastic K, in which the insert 11 formed from the material is embedded. Thus, the closure element 10 has the base body 12 and the insert 11 embedded in the base body 12, which insert is made from the material different from the plastic K. Fig. 1, the closure element 10 and thus the base body 12, the plastic K and the insert 11 are shown in a cross-sectional view and in a cross-sectional plane which runs perpendicular to the axial direction. In other words, Fig. 1 a respective cross-section of the closure element 10 and thus of the plastic K, the base body 12 and the insert 11 in the aforementioned cross-sectional plane running perpendicular to the axial direction of the rotor 1 and thus perpendicular to the axis of rotation, which is also simply referred to as the cutting plane. Fig. 1, the groove 6 is completely closed outwards by the closure element 10, i.e. covered and thereby closed, at least in the said cross-sectional plane in the radial direction of the rotor 1.

[0025] Out of Fig. 1 that the insert 11 is curved inwards, at least in the cross-sectional plane mentioned, in the radial direction of the rotor 1 and thereby towards the groove 6. As a result, the closure element 10 is designed as a self-reinforcing closure element, and thus as a self-reinforcing cover slide, since with increasing speed at which the rotor 1 rotates about the axis of rotation relative to the stator, centrifugal forces acting outwards on the closure element 10 in the radial direction of the rotor 1 increase, whereby these centrifugal forces reduce or even eliminate the curvature of the insert 11. This means that the centrifugal forces cause the insert 11 to be curved inwards less in the radial direction of the rotor 1 than in a state in which the rotor 1 is stationary relative to the stator, whereby this state in Fig. 1, wherein by such a reduction or even elimination of the curvature of the insert part 11, which in the said state runs inwards in the radial direction of the rotor 1, an extension of the insert part 11, which runs in the circumferential direction of the rotor 1 and is also referred to as length or width, increases and thus becomes or is larger than in the said state, which in Fig. 1. Due to this increase in the extension of the insert 11 running in the circumferential direction of the rotor 1, which is also referred to as an increase in extension, width or length, the closure element 10 is pressed more strongly against the laminated core 4, in particular against the teeth 8 and 9, in the circumferential direction of the rotor 1, whereby with increasing speed the closure element 10 is pressed more and more strongly against the laminated core 4 and is thus shown on the laminated core 4. This prevents unwanted detachment of the closure element 10 from the laminated core 4, so that unwanted movement of the length regions L out of the groove 6 can also be avoided. This prevents unwanted disintegration of the rotor 1 even at high speeds of the rotor 1, so that the closure element 10 is a self-reinforcing, high-speed-resistant cover slide. In the Fig. 1, the insert part 11 is fully embedded in the plastic K. The closure element 10, that is to say in particular the base body 12, is designed as an injection-molded part, that is to say as a plastic K injection-molded part, in which the insert part 11 is embedded, in particular fully.

[0026] In the Fig.1, the insert part 11 is arranged in the circumferential direction of the rotor 1 between two wall regions W1 and W2 of the rotor 1 which face one another in the circumferential direction of the rotor 1 and at least partially and, in this case, directly delimit the groove 6 in the circumferential direction of the rotor 1. The wall regions W1 and W2 are formed separately from the closure element 10. For example, the wall regions W1 and W2 are wall regions of the laminated core 4, in particular of the teeth 8 and 9. Furthermore, it is conceivable that the wall regions W1 and W2 are also formed separately from the laminated core 4. In particular, the wall regions W1 and W2 are also formed separately from the winding 2. The wall regions W1 and W2 are arranged at a distance A from one another in the circumferential direction of the rotor 1 and are thus spaced apart from one another in the circumferential direction of the rotor 1.The insert part 11 extends in the circumferential direction of the rotor 1 at least over more than half of the distance A between the wall regions W1 and W2. In the present case, the insert part 11 extends at least over more than 80%, in particular at least over 90%, of the distance A between the wall regions W1 and W2. The base body 12 and thus the plastic K extend in the circumferential direction of the rotor 1 over the entire distance A between the wall regions W1 and W2, so that in the present case the plastic K or the base body 12 directly rests on the wall regions W1 and W2, in particular is supported. As a result, the closure element 10 is particularly firmly fixed to the laminated core 4, whereby this fixation increases with increasing speed, i.e. becomes stronger.

[0027] For example, the material from which the insert part 11 is formed is a metallic material such as a steel or a light metal alloy, or the material from which the insert part 11 is formed is a fiber-reinforced plastic. List of reference symbols 1 rotor 2 windings 3 double arrow 4 sheet packages 5 double arrow 6 grooves 7 Double arrow 8 tooth 9 tooth 10 locking element 11 Insert 12 basic bodies A distance K Plastic L length ranges W1 wall area W2 wall area QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2018 / 137999 A1

[0002] WO 2022 / 023043 A1

[0002] WO 2023 / 110275 A1

[0002]

Claims

[1] Rotor (1) for an electrical machine, with at least one winding (2) for generating a magnetic field, with a laminated core (4) carrying the winding (2), which has at least one groove (6) in which longitudinal regions (L) of the winding (2) are received, and with at least one closure element (10) formed separately from the winding (2) and separately from the laminated core (4), by means of which the groove (6) is at least partially closed outwards in the radial direction (5) of the rotor (1), characterized by that the closure element (10) is formed from a plastic (K) in which an insert part (11) formed from a material different from the plastic (K) is embedded. [2] Rotor (1) according to claim 1, characterized by that the insert part (11) is curved inwards in the radial direction (5) of the rotor (1) and thus towards the groove (6). [3] Rotor (1) according to claim 1 or 2, characterized bythat the insert (11) is fully embedded in the plastic (K). [4] Rotor (1) according to one of the preceding claims, characterized by that the closure element (10) is designed as an injection-molded part. [5] Rotor (1) according to one of the preceding claims, characterized by in that the insert part (11) is arranged in the circumferential direction (7) of the rotor (1) between two wall regions (W1, W2) of the laminated core (4) which face one another in the circumferential direction (11) of the rotor (1) and at least partially delimit the groove (6) in the circumferential direction (7) of the rotor (1), wherein the wall regions (W1, W2) are arranged at a distance (A) from one another in the circumferential direction (7) of the rotor (1), and wherein the insert part (11) extends in the circumferential direction (7) of the rotor (1) at least over more than half the distance (A) between the wall regions (W1, W2). [6] Rotor (1) according to claim 5, characterized bythat the plastic (K) extends in the circumferential direction (7) of the rotor (1) over the entire distance (A) between the wall areas (W1, W2). [7] Rotor (1) according to one of the preceding claims, characterized by that the material is a metallic material. [8] Rotor (1) according to claim 7, characterized by that the metallic material is a steel or a light metal alloy. [9] Rotor (1) according to one of claims 1 to 6, characterized by that the material is a fiber-reinforced plastic which comprises a second plastic, different from the plastic, as a matrix in which reinforcing fibers are embedded. [10] Motor vehicle, with at least one electric machine which has a stator and a rotor (1) according to one of the preceding claims.

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