Rotor and method for producing rotor
The lightweight design of the rotor shaft and plate stack structure, combined with interference fit and clamp fixation, solves the problems of motor rotor weight and assembly complexity, and achieves the effects of lightweighting, reducing drag torque and improving mechanical strength.
Patent Information
- Application Number
- CN202480012069.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-02-24
- Filing Date
- 2024-02-22
- Publication Date
- 2025-09-19
AI Technical Summary
Existing motor rotors have deficiencies in weight and assembly complexity, especially the combination of embedded permanent magnets and surface magnets, which results in insufficient mechanical strength and rotational strength.
The lightweight rotor shaft and plate stack structure are fixed by interference fit and clamps between the support surface and the rotor shaft, combined with the V-shaped arrangement of the cooling channel and magnet unit to achieve a stable connection between the rotor shaft and the plate stack and simplify assembly.
The rotor is lightweight, the drag torque is reduced, and the operating behavior is improved, while the assembly process is simplified and the mechanical strength and rigidity are improved.
Smart Images
Figure CN120677614A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a rotor for an electric machine having the features of claim 1. The invention also relates to a method for producing the rotor. Background Art
[0002] Rotors for electric motors are known, which generally have a rotor core formed from a plurality of stacked single-plate laminations, wherein the rotor core has a plurality of magnet recesses distributed in the circumferential direction for accommodating permanent magnets. For rotors of permanent-magnet synchronous motors (PSMs), so-called embedded permanent magnets are generally used, which are embedded in the rotor core. Furthermore, it is known to supplement the embedded permanent magnets with surface magnets to increase efficiency. These surface magnets are arranged on the outside of the rotor core and are secured by tying the rotor core. Tying the rotor core achieves particularly high mechanical and rotational strength.
[0003] Document DE 10 2019 117 686 A1 discloses a rotor arrangement for an electric machine, comprising a rotor including a rotor core, a banding element radially surrounding the rotor core, and a plurality of rotor poles. Each rotor pole includes at least two magnet units embedded in the rotor core, i.e., inner magnet units, and at least one magnet unit arranged between the rotor core and the banding element, i.e., a surface magnet unit. Summary of the Invention
[0004] The object of the present invention is to provide a rotor of the aforementioned type which is characterized by low weight and simple assembly.
[0005] This object is achieved by a rotor having the features of claim 1 and a method having the features of claim 15. Further features, advantages and effects of the invention are described in the dependent claims, the description and the drawings.
[0006] The present invention relates to a rotor configured and / or suitable for use in an electric motor. In particular, the electric motor is configured and / or suitable for use in an electric axle drive and / or a motor vehicle drive. Preferably, the electric motor is configured as an internal rotor motor, wherein the rotor is arranged radially inwardly of the stator. For example, the electric motor can be configured as a traction machine, also known as a separate motor-generator (SMG). Particularly preferably, the electric motor is configured as a permanent magnet synchronous motor, or PSM for short.
[0007] The rotor has a rotor shaft. The rotor shaft can be designed as a single piece or as multiple pieces. In particular, the rotor shaft primarily comprises a shaft section for accommodating the laminated core, and a first bearing section and a second bearing section for accommodating the rotor bearing. In principle, the shaft section and the two bearing sections can be constructed as separate components that are connected to one another at least in the circumferential direction in a form-fitting and / or frictionally locking manner and / or materially bonded manner. Alternatively, however, the shaft section and the two bearing sections can also be manufactured from a common material section, in particular, in one piece. Specifically, the rotor shaft, with its axis of rotation, defines the rotor's rotational axis.
[0008] The rotor has a plurality of rotor poles distributed in the circumferential direction, each of which has at least one or exactly one magnet unit. Preferably, each magnet unit comprises one or more pole-generating magnets, in particular permanent magnets. Preferably, the rotor has more than four, preferably more than six, and in particular more than eight rotor poles, which are evenly distributed in the circumferential direction. Specifically, the rotor has 1n, 2n, 3n, 4n, or 5n magnet units, where n corresponds to the number of rotor poles.
[0009] The rotor has at least one or exactly one laminated core. In principle, the rotor can have exactly one laminated core. Alternatively, however, the rotor can also consist of at least two partial laminated cores, which are arranged together on the rotor shaft in a continuous and / or rotationally fixed manner in the axial direction relative to the rotor's axis of rotation. For example, the rotor can include more than two, preferably more than four, and in particular more than six partial laminated cores.
[0010] The laminated core essentially comprises a laminated core and at least one, or precisely one, insert segment for each rotor pole. Particularly preferably, the laminated core is formed from a plurality of individual laminates stacked axially relative to the rotor axis of rotation, and the insert segments are formed from a plurality of individual laminate segments stacked axially relative to the rotor axis of rotation. The individual laminates and the individual laminate segments are preferably each formed from a magnetized and / or magnetizable material, preferably a steel alloy. In particular, the individual laminates and the individual laminate segments are configured as so-called electrical steel sheets. The laminated core is preferably configured as a circumferentially closed structure, in particular, in a substantially annular shape. Alternatively, however, the laminated core can also be configured as a circumferentially segmented structure. For example, the segmentation can be performed in the circumferential direction in the pole edge region or at the pole edge. The insert segments are preferably configured separately from the laminated core or as separate components. Each rotor pole is preferably assigned precisely one insert segment.
[0011] The lamination core has a central shaft receptacle that is designed and / or suitable for non-rotatably receiving a rotor shaft. In particular, the central shaft receptacle extends continuously and / or linearly through the lamination core in the axial direction. Preferably, the central shaft receptacle is formed as a central through-opening or a central penetration, through which the rotor shaft is guided coaxially relative to the rotor axis of rotation. Specifically, the shaft receptacles of the lamination cores of all partial lamination packs overlap in the circumferential direction and are aligned in the axial direction.
[0012] In addition, the lamination core has a radially outwardly open segment housing for each rotor pole, which is configured and / or suitable for accommodating at least one of the magnet units and at least one of the insert segments. In particular, the segment housing has a contour that is complementary and / or geometrically similar to the insert segment. Preferably, the insert segment is supported at the magnet unit in a shape-fitting manner in the segment housing along the circumferential direction and / or radial direction relative to the rotor rotation axis. Preferably, the insert segment is supported at the magnet unit in a precisely fitting manner and / or without gaps. In particular, the insert segments are accommodated in the segment housing in such a way that they define the outer periphery of the rotor with their radially outer sides and / or are arranged on a common pitch circle around the rotor rotation axis.
[0013] The rotor has a binding hoop surrounding the laminated core, which holds the magnet unit and the insert segments in the corresponding segment receptacles. In particular, the magnet unit and the insert segments are clamped between the laminated core and the binding hoop. The binding hoop is preferably formed by a fiber winding, which can preferably be made of carbon fibers or other fiber materials, such as metal fibers or fiber composite materials (e.g., fiber-reinforced plastic). Specifically, the binding hoop can be made of a thermosetting plastic or a thermoplastic, or contain a thermosetting plastic or a thermoplastic.
[0014] The present invention provides for the shaft receptacle to have a plurality of support surfaces distributed in the circumferential direction, and for the rotor shaft to have a plurality of mating surfaces distributed in the circumferential direction, wherein the support surfaces each bear against a corresponding mating surface of the rotor shaft in the radial direction relative to the rotor axis of rotation. In particular, the support and mating surfaces each consist of flat surface segments, preferably extending in the axial direction relative to the rotor axis of rotation, which support and / or can support each other at least in the radial direction, in particular over their entire surface. In principle, the shaft receptacle and the rotor shaft can be connected to each other via a polygonal connection, wherein the support and mating surfaces are designed as polygonal surfaces. The shaft receptacle may have at least two, or exactly two, support surfaces, wherein the support surfaces are arranged opposite one another. However, the shaft receptacle particularly preferably has more than two support surfaces, in particular at least three, wherein the support surfaces are evenly spaced from one another in the circumferential direction. The rotor shaft particularly preferably has the same number of mating surfaces as the support surfaces of the shaft receptacle. Specifically, the shaft receptacle and the rotor shaft have a corresponding support surface and a corresponding mating surface for each rotor pole.
[0015] The advantage of the present invention is that, by supporting the laminated core via the support surfaces, a particularly rotationally fixed or form-fitting connection to the rotor shaft is established, wherein the forces acting on the connection are distributed over a large area to the rotor shaft via the support surfaces. This reduces the surface pressure between the laminated core and the rotor shaft, and also increases the rigidity of the laminated core. Consequently, the laminated core can be manufactured with a particularly low radial height, significantly reducing the overall weight of the rotor and the manufacturing costs of the laminated core. Furthermore, a rotor is provided that is characterized by a low drag torque and, therefore, improved operating behavior.
[0016] In a specific embodiment, the rotor shaft comprises a shaft section designed as a hollow shaft, wherein the mating surfaces are each formed by a cylindrical flattened portion extending parallel to the rotor's axis of rotation. In particular, the mating surfaces are uniformly spaced apart in the circumferential direction, with two adjacent cylindrical flattened portions connected to each other by a radius. Preferably, the cylindrical flattened portions each extend over more than 5%, preferably more than 8%, of the circumferential surface in the circumferential direction. Alternatively or optionally in addition, the cylindrical flattened portions each extend over an angular range of greater than 15°, preferably greater than 25°, in the circumferential direction. Particularly preferably, the support surface and the mating surface have the same width, or at least approximately the same width, at least in the circumferential or tangential direction. One advantage is that the cylindrical flattened portions provide a rotor shaft that can be manufactured in a simple manner, for example by forming. The hollow shaft design also provides a rotor characterized by particularly low weight and low inertia.
[0017] In another specific embodiment, the shaft receptacle and the rotor shaft have n-fold rotational symmetry relative to the rotor's axis of rotation, where "n" corresponds to the number of rotor poles. In other words, the shaft receptacle or rotor shaft can be reconstructed by rotating it through an angle of 360° / n. For example, the rotor has n=6 rotor poles, whereby the shaft receptacle and the rotor shaft thus have six-fold rotational symmetry. Simply put, in a six-pole rotor, the support surfaces and the mating surfaces are arranged at a distance of 60° around the axis of rotation, in particular at a center-to-center distance. The rotational symmetry thus creates a symmetrical structure for the lamination core or the rotor shaft, making assembly of the lamination core on the rotor shaft particularly simple and cost-effective.
[0018] In another specific embodiment, the outer radius of the rotor shaft is greater than 60% of the total radius of the rotor. In particular, the outer radius of the rotor shaft is between 60% and 80% of the total radius of the rotor. Thus, by designing the rotor shaft as a hollow shaft, a rotor can be provided that is characterized by a low axial height of the lamination core and a low weight.
[0019] In a further development, it is provided that at most three or exactly three of the support surfaces are designed as contact surfaces, wherein the contact surfaces are supported without play on the corresponding associated mating surfaces, in particular in the radial direction relative to the rotor axis of rotation. In particular, the contact surfaces serve for centering and / or torque transmission between the lamination core and the rotor shaft. Preferably, the contact surfaces are supported in a form-fitting and / or force-transmitting manner on the corresponding associated mating surfaces in the radial direction relative to the rotor axis of rotation. Thus, by designing at most three support surfaces as contact surfaces, overdetermination of the areas in contact with one another is avoided during assembly of the lamination stack. This further simplifies assembly.
[0020] In a specific embodiment, the contact surfaces are supported on the corresponding mating surfaces by means of an interference fit. In particular, the laminated core can be press-fitted onto the rotor shaft in the axial direction relative to the rotor axis of rotation to produce the interference fit. Preferably, the laminated core is fixed to the rotor shaft in a force-loaded manner in the axial direction relative to the rotor axis of rotation by means of the interference fit. Particularly preferably, the tolerance range of the interference fit is selected such that an interference fit that can be manually overcome and / or produced is obtained. Thus, a rotor is provided, characterized in that the laminated core can be mounted particularly securely on the rotor shaft.
[0021] In another embodiment, an interference fit is created by oversizing the corresponding mating surfaces. In other words, all support surfaces have the same radial distance from the rotor axis of rotation and / or all support surfaces contact a common pitch circle relative to the rotor axis of rotation. Alternatively, the mating surface in contact with the contact surface has a greater radial distance from the rotor axis of rotation than the remaining mating surfaces and / or the mating surface in contact with the contact surface contacts a pitch circle having a larger radius than the remaining mating surfaces.
[0022] Alternatively, an interference fit is created by oversizing the corresponding support surfaces. In other words, all mating surfaces have the same radial distance from the rotor axis of rotation and / or all mating surfaces contact a common pitch circle relative to the rotor axis of rotation. Alternatively, the contact surface has a smaller radial distance from the rotor axis of rotation than the remaining support surfaces and / or the contact surface contacts a pitch circle having a smaller radius than the remaining support surfaces.
[0023] In a further development, all additional support surfaces are designed as auxiliary surfaces, wherein, at least during assembly of the laminated core, the auxiliary surfaces support and / or can support the corresponding associated mating surfaces, particularly with clearance in the radial direction relative to the rotor axis of rotation. In particular, the auxiliary surfaces serve to provide additional support for the laminated core in the event of high torque transmission and / or high loads or deformations on the laminated core. In particular, "with clearance" means that the auxiliary surfaces are arranged with close tolerances or without overlap relative to the mating surfaces. Preferably, the auxiliary surfaces are supported and / or can support at least with a positive fit in the radial direction relative to the rotor axis of rotation on the corresponding associated mating surfaces. Preferably, the rotor has six rotor poles, wherein three of the support surfaces are designed as contact surfaces and three of the support surfaces are designed as auxiliary surfaces. Preferably, the contact surfaces and auxiliary surfaces are arranged alternately in the circumferential direction. By designing the remaining support surfaces as auxiliary surfaces, the laminated core is stably supported on the rotor shaft, thereby further increasing the rigidity of the rotor, in particular the laminated core.
[0024] In another embodiment, the auxiliary surface is supported and / or can be supported on the corresponding mating surface by a clearance fit. In particular, at least in the assembled state, a small radial gap of less than 50 μm, preferably less than 20 μm, and in particular less than 5 μm, is formed between the mating surface and the auxiliary surface. This provides a radial gap that closes easily when the laminar core is loaded, thereby allowing the auxiliary surface to rest against the mating surface.
[0025] In another specific embodiment, radial forces are applied to the laminated core by means of a binding band. Due to the radial forces, the laminated core deforms, and the auxiliary surfaces are supported without clearance on the corresponding associated mating surfaces. In other words, the laminated core deforms in the radial direction during wrapping with the binding band, causing the auxiliary surfaces to abut against the mating surfaces, or reducing or closing the radial clearance between the auxiliary surfaces and the corresponding mating surfaces. This provides a rotor characterized by a particularly stable abutment of the laminated core against the rotor shaft in the fully assembled state.
[0026] In another specific embodiment, the lamination core has a plurality of through-openings distributed and / or spaced apart in the circumferential direction. These through-openings are configured and / or suitable for forming corresponding cooling channels and / or for weight reduction. The through-openings are configured circumferentially between the support surfaces. In particular, the through-openings extend continuously and / or linearly through the lamination core in the axial direction. Preferably, the through-openings configured as cooling channels define a flow path along which coolant flows through the rotor in the axial direction relative to the rotor axis of rotation and removes heat. Specifically, the rotor lamination core has a cooling channel for each rotor pole. In principle, the through-openings can be formed by holes, penetrations, etc. introduced axially into the lamination core or the individual laminations, forming channels that are closed in the axial direction in the lamination core. However, preferably, the through-openings are formed by cutouts, penetrations, etc. introduced radially into the lamination core or the individual laminations, forming channels that open at the inner circumference in the axial direction. Preferably, the through-openings are radially bounded by the outer circumference of the rotor shaft. This allows for the production of plate cores which are characterized by a particularly low weight.
[0027] In a specific embodiment, it is provided that the rotor poles each have exactly two inner magnet units and exactly two outer magnet units, wherein the two inner magnet units are arranged in a V-shape relative to one another, and the two outer magnet units are arranged in a V-shape relative to one another. In particular, the inner magnet units are to be understood as radially inner, in particular embedded, magnet units, while the outer magnet units are to be understood as radially outer magnet units. In particular, the V-shaped arrangement of the inner and outer magnet units is open outward in the radial direction relative to the rotor axis of rotation. Preferably, the two inner magnet units and the two outer magnet units of each rotor pole are arranged at an angle, in particular at the same angle, to the radius of the rotor. Alternatively, however, the two inner magnet units and the two outer magnet units can also be arranged at different angles to the radius of the rotor. In simple terms, the inner and outer magnet units are arranged in a V-shape in two layers, or in a double V-shape. The V-shaped arrangement of the inner and outer magnet units makes it possible to optimize the rotor in terms of its drag torque in a simple manner.
[0028] In particular, it is provided that the lamination core has, for each rotor pole, an inner magnet receptacle for accommodating an inner magnet unit and an outer magnet receptacle for accommodating an outer magnet unit. In particular, the inner magnet receptacle is formed radially between the lamination core and the insertion section. In particular, the outer magnet receptacle is formed radially between the insertion section and another insertion section. Preferably, the magnet receptacle is used to accommodate the magnet units in a form-fitting and / or force-transmitting manner. To this end, the lamination core and / or the insertion section have a respective retaining structure for each magnet unit, which retaining structure fixes the respective magnet unit in a form-fitting and / or force-transmitting manner. Preferably, the retaining structure is constructed integrally with the lamination core or the insertion section, in particular from a common material section. For example, the retaining structure is constructed as a retaining lug, a constriction, a protrusion, etc. Alternatively, however, the retaining structure can also be formed by a groove formed at the lamination core and / or the insertion section. Specifically, it can be provided that the outer magnet units and / or the inner magnet units of two adjacent partial laminated cores are arranged offset by an inclination angle in the circumferential direction.
[0029] In another design solution, the rotor has a first end plate and a second end plate, which are arranged on the end side at the corresponding axial end sides of the plate stack. Here, the two end plates each have a shaft receptacle that is complementary to the rotor shaft. In particular, the shaft receptacle of the end plate has a plurality of support surfaces distributed in the circumferential direction, which are supported on the rotor shaft, in particular the corresponding mating surfaces of the shaft segment, in the radial direction relative to the rotor rotation axis. Preferably, at most three of the support surfaces are designed as contact surfaces. Particularly preferably, the shaft receptacle of the end plate has n-fold rotational symmetry. In particular, the end plate is configured as a so-called balancing plate. Specifically, the end plate is respectively arranged on one of the shaft segments and / or the bearing segments via the shaft receptacle in a manner that is non-rotatable relative to each other. This enables particularly simple assembly of the end plate on the rotor shaft.
[0030] In another embodiment, the rotor includes a central fixing device designed and / or suitable for axially securing the laminated core. To this end, the laminated core and the two end plates are fixed or clamped in the axial direction relative to the rotor's axis of rotation between an axial end stop of the rotor shaft and the fixing device. In particular, by attaching the fixing device to the rotor shaft, preferably screwing it onto the rotor shaft and tightening it with a tightening torque, axial pressure is applied to the end plates and, therefore, to the laminated core via the fixing device. This creates a press fit for the laminated core between the two end plates. Preferably, the rotor shaft, in particular one of the bearing sections, includes an axial end stop. The end stop can be configured as a circumferential flange, a shoulder, an annular shoulder, or the like. Preferably, the fixing device is configured as a shaft nut. Preferably, the rotor shaft, in particular the other bearing section, includes an external thread for this purpose, with which the shaft nut engages. Alternatively, however, the fixing device can also be configured as a compression ring. Thus, a rotor is provided in which the laminated core can be fixed or locked to the rotor shaft in a simple and cost-effective manner.
[0031] Another subject matter of the invention relates to a method for producing a rotor according to any of the preceding claims, wherein:
[0032] -Provide the rotor shaft;
[0033] The lamination core is connected to the rotor shaft in a form-fitting, in particular rotationally fixed, manner via the shaft receptacle, wherein the lamination core is radially supported on a counter surface of the rotor shaft via a support surface of the shaft receptacle;
[0034] - inserting the magnet unit and the insertion segment into the segment receptacle;
[0035] - Wrap the plate stack with lashing hoops.
[0036] In particular, provision is made for the laminated core to be produced during the manufacturing process, for example by stamping and stacking, and then to be mounted on the rotor shaft according to the method in the axial direction relative to the rotor's axis of rotation. Alternatively or optionally in addition, the individual laminated cores can also be materially connected to one another, for example by a self-adhesive coating or gluing. Preferably, the rotor can be assembled manually. Alternatively, one or more of the assembly steps can be automated or semi-automated.
[0037] In a first assembly step, the first end plate is preferably mounted on the provided rotor shaft, in particular on the first bearing section and / or shaft section. To this end, the first end plate is pushed onto the rotor shaft via the shaft receptacle until it abuts against an axial end stop. The end plate is preferably oriented by the geometry of the rotor shaft, more specifically the first bearing section and / or shaft section. In particular, the first end plate can be connected to a mating surface of the shaft receptacle in a force-fitting or friction-fitting manner to prevent the first end plate from losing its position.
[0038] In the second assembly step, the lamination core is preferably mounted on the provided rotor shaft, in particular on the shaft segment. To this end, the lamination core is pushed onto the shaft segment via the shaft receptacle until it rests against the first end plate. The lamination core is preferably oriented by the geometry of the rotor shaft, or more precisely, the shaft segment. In particular, the lamination core can be connected by force or friction via the contact surface of the shaft receptacle and the mating surface to prevent the lamination core from shifting out of position.
[0039] In the third assembly step, filler bodies can be inserted into the respective through-openings of the lamination core to form cooling channels. To this end, the filler bodies are pushed into the respective associated through-openings in the axial direction relative to the rotor's axis of rotation until they rest against the first end plate. The filler bodies are preferably oriented by the geometry of the rotor shaft, or more precisely, the shaft segments.
[0040] In a fourth assembly step, the second end plate is preferably mounted on the provided rotor shaft, in particular on the second bearing section and / or shaft section. To this end, the second end plate is pushed onto the rotor shaft via the shaft receptacle until the second end plate rests against the lamination core. Preferably, the second end plate is oriented by the geometry of the rotor shaft, more precisely the second bearing section and / or shaft section. In particular, the second end plate can be connected to the mating surface via the contact surface of the shaft receptacle in a force-transmitting or friction-fitting manner to prevent the second end plate from being dislocated. Alternatively, all magnet units and all insert elements can first be installed in the segment receptacle (as described below) and only then the second end plate can be installed.
[0041] In a fifth assembly step, the fixing device is preassembled on the provided rotor shaft, in particular on the second bearing segment. To this end, the locking device is screwed onto the second bearing segment until the locking device and thus the second end plate are prevented from losing their position.
[0042] In a further assembly step, the magnet units and the insert segments can be inserted into the corresponding segment receptacles. To this end, the magnet units and the insert segments can be installed pole by pole. For example, the assembled magnet units and the insert segments can be held in the corresponding associated segment receptacles by means of an assembly device in a position-proof manner. It is preferably provided that the magnet units and the insert segments of the rotor poles are placed in the associated segment receptacles and then fixed by means of an assembly device. For example, the assembly device can be used here as a transport fixture. Preferably, after all magnet units and insert segments have been assembled, the fixing device can apply a predetermined assembly force in order to apply pressure to the plate core, the magnet units and the insert segments between the two end plates or to fix them without gaps.
[0043] In the final assembly step, the laminated core is wrapped with a binding wire. Preferably, the laminated core is wrapped with a binding wire, which comprises one or more filaments, in particular carbon fibers. For this purpose, the wire ends can be fixed to an assembly device, and the binding wire is then wound around the outer circumference of the laminated core in one or more layers. The binding wire is wound around the laminated core with a defined pretension, thereby exerting a radial force or contact pressure on the laminated core, in particular the core, causing it to rest with its auxiliary surface against the mating surface. BRIEF DESCRIPTION OF THE DRAWINGS
[0044] Other features, advantages and effects of the present invention are given by the following description of preferred embodiments of the present invention, wherein:
[0045] Figure 1 shows an axial view of a rotor for an electric machine as an embodiment of the present invention;
[0046] Figure 2 Shown Figure 1 Detailed view of the middle rotor;
[0047] Figure 3 Shown Figure 1 an axial view of the rotor shaft of the mid-rotor;
[0048] Figure 4 Shown Figure 1 a cross-sectional view of the middle rotor along the rotor rotation axis;
[0049] Figure 5 Shown Figure 1 A perspective view of the end plate of the middle rotor;
[0050] Figure 6 An axial view of an alternative embodiment of a rotor is shown. DETAILED DESCRIPTION
[0051] Figure 1 The figure shows an axial view of a rotor 1 relative to a rotor axis of rotation 100 , which is designed or suitable for an electric machine (not shown) for an electric vehicle. The electric machine is a permanent magnet synchronous machine in this case.
[0052] In the illustrated embodiment, the rotor 1 includes six rotor poles 2 evenly distributed in a circumferential direction about the rotor axis of rotation 100, wherein each rotor pole 2 has two inner magnet units 3a, 3b and two outer magnet units 4a, 4b. The inner magnet units 3a, 3b and the outer magnet units 4a, 4b are each formed by at least one pole-generating magnet, which is configured as a rod-shaped permanent magnet, for example. In the illustrated embodiment, the inner magnet units 3a, 3b and the outer magnet units 4a, 4b are each arranged in a V-shape, wherein the inner magnet units 3a, 3b are located radially inwardly and the outer magnet units 4a, 4b are located radially outwardly.
[0053] The rotor 1 includes at least one laminated core 5, which is essentially formed from a star-shaped laminated core 6 and, for each rotor pole 2, a corresponding insertion segment 7 and a corresponding further insertion segment 8. The insertion segments 7, 8 of each rotor pole 2 are each received in a positively locking manner in a segment receptacle 9 formed on the laminated core 6. The laminated core 6 is formed from a plurality of individual laminates 10 stacked one on top of another in the axial direction relative to the rotor axis of rotation 100, while the insertion segments 7 and the further insertion segments 8 are formed from a plurality of individual laminate segments 11 stacked one on top of another in the axial direction relative to the rotor axis of rotation 100. For example, the individual laminates 10 and the individual laminate segments 11 can each be produced by stamping and stacking and connected to one another.
[0054] An inner magnet receptacle 12 is formed between the laminar core 6 and the insertion section 7 , which is used to accommodate the two inner magnet units 3a, 3b. Furthermore, an outer magnet receptacle 13 is formed between the insertion section 7 and the further insertion section 8 , which is used to accommodate the two outer magnet units 4a, 4b. For example, the magnet units 3a, 3b, 4a, 4b are held captive, for example, in the respective magnet receptacles 12, 13 in a form-fitting and / or force-locking manner. For this purpose, the laminar core 6 and the insertion section 7 may each include corresponding recesses, retaining structures, or the like. In the assembled state, the insertion section 7 forming the inner magnet receptacle 12 is supported radially and circumferentially by the two inner magnet units 3a, 3b, and the further insertion section 8 forming the outer magnet receptacle 13 is supported radially and circumferentially by the two outer magnet units 4a, 4b.
[0055] The rotor 1 also has a binding hoop 14 that surrounds the laminated core 5 at its outer circumference. The binding hoop 14 serves to hold the individual components of the rotor 1 together and to provide thermal insulation for the rotor 1. The inner magnet units 3a, 3b and the outer magnet units 4a, 4b, as well as the insert segments 7, 8, are each captively held or clamped in the segment receptacles 9 between the laminated core 6 and the binding hoop 14. For example, the binding hoop 14 can be formed by winding carbon fibers.
[0056] The laminated core 6 has a corresponding through-opening 15 for each rotor pole 2. This through-opening serves to form a cooling channel 16 and simultaneously reduces weight. The through-openings 15 are formed circumferentially on the inner periphery of the laminated core 6 between the magnet receptacles 3a, 3b, 4a, 4b of two adjacent poles 2 and are located along a radially extending q-axis 101 along which the pole edges of the rotor poles 2 extend. The through-openings 15 extend parallel to the rotor axis of rotation 100.
[0057] The laminated core 6 also has a central shaft receptacle 17, via which the laminated core 5 is arranged in a rotationally fixed manner on a rotor shaft 18. For this purpose, the rotor shaft 18 is guided coaxially with respect to the rotor axis of rotation 100 through the shaft receptacle 17, wherein the shaft receptacle 17 penetrates the laminated core 6 in the axial direction relative to the rotor axis of rotation 100.
[0058] The rotor 1 has a plurality of filling bodies 19, which are inserted into the through-opening 15 in the axial direction relative to the rotor axis of rotation 100, in order to form at least one cooling channel 16 between the lamination core 6 and the rotor shaft 18. To this end, the filling bodies 19 have one or more spacing contours 20 on their outer sides facing the lamination core 6, by means of which the filling bodies 19 are supported at a distance from the lamination core 3 with a slight gap in the radial direction relative to the rotor axis of rotation 100, in order to form the cooling channel 16. On their inner sides facing the rotor shaft 18, the filling bodies 19 are supported in a positively locking and / or frictionally locking manner on the outer circumference of the rotor shaft 18 in the radial direction.
[0059] The laminated core 6 is connected to the rotor shaft 17 in a positively locking and / or force-locking manner in the circumferential direction about the rotor axis of rotation 100 via the shaft receptacle 17. To this end, the shaft receptacle 17 has a corresponding support surface 21 for each rotor pole 2, which is supported on a mating surface 22 formed on the rotor shaft 18. The support surfaces 21 and the mating surfaces 22 are each designed as flat surface segments that rest against each other in a radial direction relative to the rotor axis of rotation 100, at least in a positively locking manner. To avoid overdetermination, three of the support surfaces 21 are designed as contact surfaces 23, while the remaining support surfaces 21, in particular three support surfaces 21, are designed as auxiliary surfaces 24. The contact surfaces 23 and auxiliary surfaces 24 are arranged alternately in the circumferential direction. In other words, the contact surfaces 23 are arranged so as to be offset by 120 degrees in the circumferential direction about the rotor axis of rotation 100. To form the contact surfaces 23, the respective support surfaces 21 are supported on the respective associated mating surfaces 22 by means of an interference fit, so that the laminar core 6 is centered during assembly by means of the contact surfaces 23. To form the auxiliary surfaces 24, the respective support surfaces 21 are arranged on the respective associated mating surfaces 22 by means of a clearance fit, wherein during assembly of the binding 14, the auxiliary surfaces 24 bear at least positively against the respective mating surfaces 22.
[0060] The rotor 1 includes at least one clamping device receptacle 25 for each rotor pole 2 for accommodating a clamping device, which can be installed in the clamping device receptacle 25, for example, for assembly purposes. In the embodiment shown, the clamping device receptacle 25 is formed in the further insertion section 8 and extends parallel to the rotor rotation axis 100, wherein the clamping device receptacles 25 of all the laminated cores 5a, 5b are arranged so as to coincide with one another or to be aligned with one another.
[0061] Figure 2 Shown Figure 1Detailed view of rotor 1. To create an interference fit, the mating surface 22 of rotor shaft 18 that contacts contact surface 23 can be made larger than the mating surface 22 of rotor shaft 18 that contacts auxiliary surface 24. Consequently, the support surfaces 21 formed on lamination core 6 all have the same radial distance from rotor axis 100 or contact a common pitch circle relative to rotor axis 100. During assembly, the support surface 21 that contacts the larger mating surface 22 thus forms contact surface 23.
[0062] In the assembled state, before the binding clip 14 is installed, a small radial gap (e.g., less than 10 μm) forms between the auxiliary surface 24 and the mating surface 22 . During the assembly process, particularly during the winding process, the binding clip 14 generates a radial force F1 that acts radially on the laminated core 6 in the direction of the rotor axis of rotation 100 . The radial force F1 is generated by the tensile force applied to the binding clip 14 , particularly the binding wire, during the winding process. The radial force F1 causes the laminated core to deform, particularly in the radial direction relative to the rotor axis of rotation 100 , so that the auxiliary surface 24 rests without gap against the corresponding associated mating surface 22 .
[0063] The through-opening 15 is formed in the circumferential direction between two adjacent support surfaces 21 in the laminar core 6. The through-opening 15 can be formed by a cutout that is delimited in the radial direction by a radius 26 of the rotor shaft 18. For example, the filler body 19 bears directly against the radius of the rotor shaft 18 in a positively locking and / or force-fitting manner in the radial direction relative to the rotor axis of rotation 100.
[0064] like Figure 3 As shown, the rotor shaft 18 has exactly six mating surfaces 22, wherein the mating surfaces 22 are distributed equidistantly from one another in the circumferential direction. The rotor shaft 18 has a shaft section 27 designed as a hollow shaft, wherein the mating surfaces 22 are each formed by a cylindrical flattened portion of the shaft section 27 extending parallel to the rotor axis of rotation 100. The mating surfaces 22 and the radii 26 are arranged alternately in the circumferential direction, thereby producing n-fold rotational symmetry, where "n" corresponds to the number of rotor poles 2. In the illustrated embodiment, the rotor shaft 18, more precisely the shaft section 27, and therefore the shaft receptacle 17, has six-fold rotational symmetry.
[0065] For example, the seating surface 22 extends over more than 5% and / or less than 10% of the total circumferential surface of the shaft section 27. In other words, the seating surface 22 extends over an angular range 102 of at least or exactly 30 degrees. This allows the laminar core 6 to be supported particularly stably on the shaft section 27.
[0066] like Figure 4As shown, the rotor shaft 18 has a first bearing section 28a and a second bearing section 28b, wherein the two bearing sections 28a, 28b and the shaft section 27 are designed as separate components. The two bearing sections 28a, 28b can be connected to the shaft section 27, for example, in a form-fitting and / or force-locking manner, preferably in a rotationally fixed manner. The two bearing sections 28a, 28b primarily serve to rotatably support the rotor shaft 18 in the housing of the electric machine. For this purpose, rotor bearings, such as rolling bearings, can be mounted on the first bearing section 28a and / or the second bearing section 28b.
[0067] The rotor 1 includes a first end plate 29a and a second end plate 29b, each of which is arranged coaxially with respect to the rotor axis of rotation 100 at the axial end faces of the laminated core 5. The two end plates 29a, 29b are designed as balancing plates that are independently configured relative to the laminated core 5 or the two bearing sections 28a, 28b. The first end plate 29a is supported at its first axial end face in an axially positively locking manner between the first bearing section 28a and the laminated core 5, and in a radially and circumferentially positively locking, in particular, fixedly secured against rotation, on the first bearing section 28a and / or the shaft section 27. The second end plate 29b is supported at its second axial end face in an axially positively locking manner between the second bearing section 28b and the laminated core 5, and in a radially and circumferentially positively locking, in particular, fixedly secured against rotation, on the second bearing section 28b and / or the shaft section 27.
[0068] For this purpose, the first bearing section 28a has an axial end stop 30 on its outer circumference, which is configured around the rotor rotation axis 100. For example, the end stop 30 is formed by an annular shoulder around the rotor rotation axis 100. The end stop 30 serves to axially support the first end plate 29a at the first bearing section 28a.
[0069] Furthermore, the second bearing section 29b has an external thread 31, via which a fastening device 32 can be mounted, or more precisely screwed, onto the second bearing section 29b. The fastening device 32 is formed, for example, by a spindle nut. The fastening device 32 serves to exert an axial pressure force F2 on the second end plate 29b and thus on the laminated core 5 in order to create a press fit for the laminated core 5 between the two end plates 29a, 29b.
[0070] As from Figure 4 As can be seen, the shaft section 27 has an outer radius R1 that is greater than 60% of the total radius R2 of the rotor 1 or the laminated core 5. For example, the outer radius R1 of the shaft section 27 is between 60% and 70% of the total radius R2. Thus, a rotor 1 is provided that is characterized by a particularly low radial height of the laminated core 5 and, therefore, a particularly low weight.
[0071] Figure 5A perspective view of one of the two end plates 29a, 29b is shown. For example, both end plates 29a, 29b can be constructed as identical components and made of stainless steel. Each end plate 29a, 29b has a central shaft receptacle 33, by which the end plates 29a, 29b are fixedly mounted on the rotor shaft 18, in particular the shaft section 27 and / or the associated bearing sections 28a, 28b, in a rotationally fixed manner. To this end, the shaft receptacle 33 has a plurality of support surfaces 34 distributed in the circumferential direction, which interact, for example, with the mating surface 22 of the shaft section 27. Three of the support surfaces 33 can be designed as contact surfaces 23, and three of the support surfaces 33 can be designed as auxiliary surfaces 24.
[0072] Furthermore, the end plates 29a, 29b have a plurality of through-holes 35 which are introduced into the outer diameter of the end plates 29a, 29b in a uniformly distributed manner in the circumferential direction. On the one hand, the through-holes 35 serve to accommodate a clamping device (not shown), wherein the individual through-holes 35 are connected to the outer diameter of the end plates 29a, 29b in a uniformly distributed manner in the circumferential direction. Figure 1 The corresponding one in the shown clamping device receiving portion 25 is arranged to overlap. Optionally, the through hole 35 is used to accommodate a balancing weight. For example, the balancing weight can be installed in the through hole 35 in a form-fitting and / or force-transmitting manner for this purpose.
[0073] Figure 6 An alternative embodiment of a rotor 1 is shown, which has only one outer magnet unit 4a and one insert section 7 per rotor pole 2, rather than two outer magnet units 4a, 4b. In the illustrated embodiment, the inner magnet units 3a, 3b are arranged in a V-shape, with the outer magnet unit 4a positioned radially outward and tangentially oriented between the insert section 7 and the binding band 14. Consequently, the outer magnet unit 4a is located both radially outward of the insert section 7 and on the binding band 14. To this end, the insert section 7 has a recess on its outer side as an outer magnet receptacle 13, into which the outer magnet unit 4a is inserted. In the assembled state, the insert section 7, which forms the inner magnet receptacle 12, is supported radially and circumferentially by the two inner magnet units 3a, 3b with a positive fit, with the outer magnet receptacle 13 being formed radially between the insert section 7 and the binding band 14.
[0074] Reference Signs List
[0075] 1 rotor
[0076] 2 rotor poles
[0077] 3a, 3b inner magnet unit
[0078] 4a, 4b external magnet unit
[0079] 5 Plate stack
[0080] 6 Plate core
[0081] 7 Insert section
[0082] 8 Another insert section
[0083] 9 Segment accommodation part
[0084] 10 single board
[0085] 11 Single board section
[0086] 12 Inner magnet housing
[0087] 13 External magnet receiving portion
[0088] 14 Binding Hoop
[0089] 15 Through opening
[0090] 16 cooling channels
[0091] 17 Shaft accommodating portion
[0092] 18 rotor shaft
[0093] 19 Filling
[0094] 20 Interval Contours
[0095] 21 Support surface
[0096] 22 mating surface
[0097] 23 contact surface
[0098] 24 auxiliary surfaces
[0099] 25 Clamping device receiving portion
[0100] 26 Radius
[0101] 27 Shaft section
[0102] 28a, 28b support sections
[0103] 29a, 29b end plates
[0104] 30 End stop
[0105] 31 external thread
[0106] 32 Fixtures
[0107] 33 Another shaft receiving portion
[0108] 34 Another support surface
[0109] 35 through holes
[0110] 100 Rotor axis of rotation
[0111] 101 q axis
[0112] 102 Angle range
[0113] F1 radial force
[0114] F2 pressure
[0115] R1 outer radius
[0116] R2 total radius
Claims
1. A rotor (1) for an electric motor, comprising: - a rotor shaft (18); - a plurality of rotor poles (2) distributed in the circumferential direction, each of the rotor poles having at least one magnet unit (3a, 3b, 4a, 4b); - at least one laminated core (5) having a laminated core (6) and at least one insert section (7, 8) for each rotor pole (2), wherein: The lamination core (6) has a central shaft receptacle (17) for accommodating the rotor shaft (18) in a rotationally fixed manner, and for each rotor pole (2) has a radially outwardly open segment receptacle (9) for accommodating at least one of the magnet units (3a, 3b, 4a, 4b) and at least one of the insertion segments (7, 8); a binding hoop (14) surrounding the laminated core (5), by means of which the magnet units (3a, 3b, 4a, 4b) and the insertion segments (7, 8) are held in the corresponding segment receptacles (9), It is characterized in that The shaft receiving portion (17) has a plurality of supporting surfaces (21) distributed in the circumferential direction, and the rotor shaft (18) has a plurality of mating surfaces (22) distributed in the circumferential direction, wherein the supporting surfaces (21) are respectively supported on the corresponding mating surfaces (22) of the rotor shaft (18) in the radial direction relative to the rotor rotation axis (100).
2. The rotor (1) according to claim 1, characterized in that The rotor shaft (18) has a shaft section (27) designed as a hollow shaft, wherein the seating surfaces (22) are each formed by a cylindrical flattened portion of the shaft section (27) extending parallel to the rotor rotation axis (100).
3. The rotor (1) according to claim 1 or 2, characterized in that The shaft receptacle (17) and the rotor shaft (18) have n-fold rotational symmetry, wherein "n" corresponds to the number of rotor poles (2).
4. A rotor (1) according to any one of the preceding claims, characterised in that The outer radius (R1) of the rotor shaft (18) is greater than 60% of the total radius (R2) of the rotor (1).
5. A rotor (1) according to any one of the preceding claims, characterised in that A maximum of three supporting surfaces (21) are designed as contact surfaces (23), which are supported without play on the respectively associated counter surface (22).
6. The rotor (1) according to claim 5, characterized in that The contact surface (23) is supported on the corresponding mating surface (22) by means of an interference fit.
7. The rotor (1) according to claim 6, characterized in that The interference fit is produced selectively by oversizing the corresponding mating surface (22) or the corresponding supporting surface (21).
8. The rotor (1) according to any one of claims 5 to 7, characterized in that All other supporting surfaces (21) are designed as auxiliary surfaces (24) which are supported with play on the respectively associated counter surfaces (22) at least when the plate core (6) is assembled.
9. The rotor (1) according to claim 8, characterized in that The auxiliary surface (24) is supported on the corresponding fitting surface (22) by means of a clearance fit.
10. The rotor (1) according to claim 8 or 9, characterized in that A radial force (F1) acts on the laminated core (5) via the binding hoop (14), so that the auxiliary surface (24) is supported without play on the corresponding associated counter surface (22) due to the deformation of the laminated core (6).
11. A rotor (1) according to any one of the preceding claims, characterised in that The plate core (6) has a plurality of through-openings (15) distributed in the circumferential direction for forming cooling channels (16) and / or for reducing weight, wherein the through-openings (15) are formed between the support surfaces (21) in the circumferential direction.
12. A rotor (1) according to any one of the preceding claims, characterised in that The rotor poles (2) each have exactly two inner magnet units (3a, 3b) and exactly two outer magnet units (4a, 4b), wherein the respective two inner magnet units (3a, 3b) are arranged in a V-shape relative to each other and the respective two outer magnet units (4a, 4b) are arranged in a V-shape relative to each other.
13. A rotor (1) according to any one of the preceding claims, characterised in that A first end plate (29a) and a second end plate (29b) are provided, which are each arranged at an end side at an axial end side of the laminated core (5), wherein the two end plates (29a, 29b) each have a shaft receptacle (33) complementary to the rotor shaft (18).
14. The rotor (1) according to claim 13, characterized in that A central fixing device (32) is provided for axially fixing the laminated core (5), wherein the laminated core (5) and two end plates (29a, 29b) are fixed in the axial direction relative to the rotor axis of rotation (100) between an axial end stop (30) of the rotor shaft (18) and the fixing device (32).
15. Method for producing a rotor (1) according to any one of the preceding claims, wherein: - providing said rotor shaft (18); The lamination core (6) is connected to the rotor shaft (18) in a form-fitting manner via the shaft receiving portion (17), wherein the lamination core (6) is radially supported on a mating surface (22) of the rotor shaft (18) via a supporting surface (21) of the shaft receiving portion (17); - inserting the magnet unit (3a, 3b, 4a, 4b) and the insertion segment (7, 8) into the segment receiving portion (9); - Wrapping the plate pack (5) with the binding hoop (14).
Citation Information
Patent Citations
Rotor device for an electric machine, in particular for a vehicle drive for an electric vehicle
DE102019117686A1