Rotor and motor
By designing a plate-shaped multipole magnet and a rotor structure with a gap in the IPM motor, the problems of reduced magnetic flux density and decreased torque constant caused by the expansion of the stator-rotor gap were solved, and the iron loss and torque constant were optimized.
Patent Information
- Application Number
- CN202010578043.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Priority Date
- 2019-06-26
- Filing Date
- 2020-06-23
- Publication Date
- 2025-01-14
- Estimated Expiration
- 2040-06-23
AI Technical Summary
In an IPM motor, the increased gap between the stator and rotor leads to a decrease in magnetic flux density, a decrease in the absolute value of inductance, electromagnetic torque and reluctance torque, a decrease in torque constant, and an increase in iron loss.
A rotor structure is designed that uses plate-shaped multi-pole magnets set at a specific angle on the rotor core and forms a gap on the rotor core to suppress the decrease of torque constant and reduce iron loss, and avoid the expansion of the gap between the stator and rotor.
It effectively suppressed the decrease in torque constant and reduced iron loss, while avoiding the widening of the gap between the stator and rotor, thus improving the performance of the motor.
Smart Images
Figure CN112152352B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a rotor and a motor. Background Art
[0002] As a motor, an IPM (Interior Permanent Magnet) type motor in which a magnet is buried inside a rotor core is known.
[0003] International Publication No. 2012 / 157107 discloses a method for manufacturing a rotor, in which cut magnet segments are assembled onto a rotor core in a state in which the cut surfaces of the magnet segments are meshed with each other. Summary of the invention
[0004] However, in an IPM motor, when the gap between the stator (stator core) and the rotor (rotor core) is enlarged, the magnetic flux density of the stator and the rotor is reduced, so the iron loss at low load can be suppressed. However, when the gap between the stator core and the rotor core is enlarged, the absolute value of the motor inductance decreases, the electromagnetic torque and the reluctance torque both decrease, and the torque constant decreases.
[0005] Therefore, an object of the present invention is to provide a rotor and a motor which can minimize the decrease in torque constant and reduce iron loss without increasing the gap between the stator and the rotor.
[0006] A first aspect of the present invention is a rotor comprising:
[0007] Rotor core;
[0008] a plate-shaped multi-pole magnet provided on the rotor core with a pair of magnetic pole faces positioned in a direction intersecting with a radial direction of the rotor core; and
[0009] A plurality of gaps are formed in the rotor core and are in contact with the magnetic pole faces of the magnets of the plurality of poles on the side close to the central axis of the rotor core.
[0010] A second aspect of the present invention is a motor comprising:
[0011] The above rotor and stator.
[0012] According to the present invention, it is possible to suppress a decrease in the torque constant as much as possible and reduce the iron loss without increasing the gap between the stator and the rotor.
[0013] The above objects, features and advantages will be easily understood from the following description of the embodiments described with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 It is a schematic diagram showing a part of the motor according to the present embodiment.
[0015] Figure 2 Yes means Figure 1 Schematic diagram of the rotor.
[0016] Figure 3 It means Figure 1 Graph of motor-related simulation results (1).
[0017] Figure 4 It means Figure 1 A graph of motor-related simulation results (2).
[0018] Figure 5 So with Figure 2 The schematic diagram of the rotor of Modification 1 is shown from the same viewpoint.
[0019] Figure 6 So with Figure 2 The schematic diagram of the rotor of Modification 2 is shown from the same viewpoint. DETAILED DESCRIPTION
[0020] Hereinafter, the present invention will be described in detail with reference to the preferred embodiments and the accompanying drawings.
[0021] [Implementation Method]
[0022] Figure 1 Schematic diagram showing a part of the motor 10 of this embodiment. Figure 1 , the motor 10 is shown as viewed from the axial direction of the motor shaft. The motor 10 includes a stator 12 and a rotor 14.
[0023] The stator 12 generates a force for rotating the rotor 14 and is disposed on the outer peripheral side of the rotor 14 with a gap therebetween. The stator 12 includes a stator core 20 and a plurality of coils 22.
[0024] The stator core 20 includes a core body 20A formed in a tubular shape and a plurality of teeth 20B protruding from the inner circumferential surface of the core body 20A toward the central axis of the core body 20A at intervals in the circumferential direction of the core body 20A. In addition, the core body 20A may be formed in a tubular shape by joining a plurality of split core sheets in the circumferential direction. The plurality of coils 22 are respectively provided on one or more teeth 20B.
[0025] The rotor 14 is rotated by the force generated by the stator 12 and is arranged on the inner circumference of the stator 12 with gaps between the plurality of teeth 20B of the stator core 20. The rotor 14 has a rotor core 30 and a plurality of magnets 32. In the present embodiment, the rotor 14 has four poles.
[0026] The rotor core 30 is formed into a tubular shape having a through hole 30H for inserting the motor shaft. In addition, the rotor core 30 may be formed into a tubular shape by laminating a plurality of plates such as electromagnetic steel. The central axis AX of the rotor core 30 coincides with the central axis of the core body 20A of the stator core 20 and the central axis of the motor shaft.
[0027] The magnets 32 of multiple poles are respectively arranged on the rotor core 30. The magnets 32 of multiple poles are respectively of substantially the same shape and size, and are symmetrically arranged inside the rotor core 30 at intervals in the circumferential direction of the rotor core 30. The magnets 32 of multiple poles extend from one end surface to the other end surface of the tubular rotor core 30.
[0028] In the above-mentioned motor 10, the rotor 14 rotates due to the interaction between the magnetic field generated in the stator 12 by the current flowing through the plurality of coils 22 in the stator 12 and the magnetic field generated by the magnets 32 of the plurality of poles in the rotor 14. When the rotor 14 rotates, the motor shaft inserted into the through hole 30H of the rotor 14 rotates in conjunction with the rotation of the rotor 14.
[0029] Next, use Figure 2 The rotor 14 will be described in more detail. Figure 2 Yes means Figure 1 A schematic diagram of the rotor 14 is shown. Figure 2 , the rotor 14 is shown when viewed from the axial direction of the central axis AX of the rotor core 30 .
[0030] In the present embodiment, the magnets 32 of multiple poles are respectively divided into a pair of magnet pieces 32A and 32B whose magnetic poles are oriented in the same radial direction relative to the rotor core 30. Each magnet piece 32A and 32B obtained by division is roughly the same shape and the same size, and has a pair of magnetic pole faces F1 and F2. The pair of magnetic pole faces F1 and F2 are respectively located in the direction intersecting the radial direction of the rotor core 30. In the present embodiment, the magnetic pole face F1 facing the outer peripheral side of the rotor core 30 and the magnetic pole face F2 facing the inner peripheral side of the rotor core 30 in the pair of magnetic pole faces F1 and F2 are roughly parallel. In addition, the pair of magnetic pole faces F1 and F2 are respectively located at the top of the part of the magnetic pole having the S pole or the N pole, and in the present embodiment, they are equivalent to the widest surface of the plate-shaped magnet pieces 32A and 32B.
[0031] A plurality of gaps 34 are formed on the rotor core 30 to minimize the decrease in torque constant and reduce iron loss. The plurality of gaps 34 are provided corresponding to the magnet pieces 32A and 32B obtained by segmentation. That is, the number of gaps is the number obtained by multiplying the number of segments of the magnet 32 segmenting one pole by the number of poles.
[0032] When the rotor 14 is viewed from the axial direction of the central axis AX of the rotor core 30, the plurality of gaps 34 are closed spaces surrounded by the rotor core 30 and the magnet pieces 32A or 32B. Figure 1 and Figure 2 In the example shown, when the rotor 14 is viewed from the axial direction of the central axis AX of the rotor core 30 , the shape of each of the plurality of gaps 34 is substantially the same as the outer shape of the magnet piece 32A or 32B, but may be different from the outer shape of the magnet 32 .
[0033] The plurality of gaps 34 are respectively connected to the magnetic pole surface F2 facing the inner circumference of the rotor core 30. In other words, the plurality of gaps 34 are respectively connected to the magnetic pole surface F2 close to the central axis AX side of the rotor core 30. A support member 30S is provided on the magnetic pole surface F2 side. In the present embodiment, the support member 30S is a pair of protrusions protruding from the rotor core 30 to the side of the gap 34 across the gap 34, and supports each magnetic piece 32A, 32B obtained by segmentation.
[0034] The plurality of gaps 34 are respectively in contact with the entirety of the magnetic pole surface F2 except for the area in contact with the support member 30S (each of a pair of protrusions). When the rotor 14 is observed axially from the center axis AX of the rotor core 30, the plurality of gaps 34 are respectively in contact with the entirety of the long side of the plate-like magnet piece 32A or 32B on the side close to the center axis AX of the rotor core 30 except for the area in contact with the support member 30S.
[0035] In addition, a plurality of magnetic isolation portions 36 for suppressing the leakage of magnetic flux generated from the magnets 32 are formed on the rotor core 30. The plurality of magnetic isolation portions 36 are respectively arranged on both sides of the width direction end of each of the magnets 32 of the plurality of poles, and are gaps connected to the end. In the present embodiment, the magnets 32 of the plurality of poles are respectively divided into a pair of magnet pieces 32A and 32B. Therefore, the magnetic isolation portions 36 on both sides of the magnet 32 of one pole are arranged on the side of the width direction end of the magnet piece 32A on one side away from the magnet piece 32B on the other side, and on the side of the width direction end of the magnet piece 32B on the other side away from the magnet piece 32A on one side.
[0036] Next, use Figure 2 , the respective angles of the magnets 32 of the plurality of poles based on the center of the rotor 14 when the rotor 14 is observed from the axial direction of the central axis AX of the rotor core 30 are described in more detail. However, since the respective angles of the magnets 32 of the plurality of poles based on the center of the rotor 14 are the same, the angle of the magnet 32 of one pole based on the center of the rotor 14 is described here.
[0037] In this embodiment, when the rotor 14 is observed axially from the central axis AX of the rotor core 30, the angle (hereinafter referred to as the magnet angle) θ between the two straight lines obtained by connecting each of the two vertices P1 and P2 of the magnet 32 of one pole and the center of the rotor core 30 is smaller than the value obtained by dividing 360° by the number of poles of the magnet 32.
[0038] Specifically, the two vertices P1 and P2 are vertices that are farthest from each other on the side close to the central axis AX of the rotor core 30 in a pair of magnet pieces 32A and 32B of the magnet 32 constituting one pole. That is, the vertex P1 is the vertex on the side away from the magnet piece 32B on the other side, among the two vertices on the inner circumference side of the rotor core 30 in the magnet piece 32A on one side, and the vertex P2 is the vertex on the side away from the magnet piece 32A on the other side, among the two vertices on the inner circumference side of the rotor core 30 in the magnet piece 32B on the other side.
[0039] In this embodiment, since the rotor 14 has four poles, the magnet angle θ is smaller than 90°. In other words, the magnet pieces 32A and 32B of the magnet 32 constituting one pole are arranged inside the rotor core 30 so that the magnet angle θ is smaller than 90°.
[0040] Here, Figure 3 and Figure 4 A graph showing simulation results of the motor 10 with respect to the magnet angle θ. Figure 3 This is a graph showing changes in the iron loss reduction rate and the torque reduction rate when the magnet angle θ is 82.73°. Figure 4 Graph showing the change of iron loss reduction rate and torque reduction rate when the magnet angle θ is 61.28°. The iron loss reduction rate is the reduction rate of the iron loss of the rotor core 30 when there is no load. The torque reduction rate is the reduction rate of the maximum total torque generated in the motor 10.
[0041] Figure 3 and Figure 4 The dotted line in the graph shows the iron loss reduction rate and torque reduction rate when the contact area of the gap 34 with respect to the magnetic pole surface F2 is kept constant and the spacing of the gap between the stator core 20 and the rotor core 30 is increased. In addition, the spacing of the gap between the stator core 20 and the rotor core 30 increases from the right side to the left side of the paper.
[0042] Figure 3 and Figure 4 The solid line in the graph shows the iron loss reduction rate and torque reduction rate when the gap between the stator core 20 and the rotor core 30 is kept constant and the contact area of the gap 34 with respect to the magnetic pole surface F2 is increased. In addition, the contact area of the gap 34 with respect to the magnetic pole surface F2 increases from the right side to the left side of the paper.
[0043] Under the condition that the magnet angle θ is 82.73° ( Figure 3 ), the iron loss reduction rate when the gap between the stator core 20 and the rotor core 30 is increased (the dotted line in the graph) is greater than the torque reduction rate when the contact area of the gap 34 relative to the pole surface F2 is increased (the solid line in the graph).
[0044] In contrast, under the condition that the magnet angle θ is 61.28° ( Figure 4 ), compared with the case where the gap between the stator core 20 and the rotor core 30 is increased (the dotted line in the curve graph), the iron loss reduction rate in the case where the contact area of the gap 34 relative to the pole surface F2 is increased (the solid line in the curve graph) is greater than the torque reduction rate.
[0045] That is, when the magnet angle θ is 61.28°, the iron loss reduction rate can be made greater than the maximum total torque reduction rate generated by the motor 10 without increasing the gap between the stator core 20 and the rotor core 30 .
[0046] Although not shown in the figure, it is known that if the magnet angle θ is less than 61.28°, the above effect can be obtained regardless of the shape of the magnet 32 (magnet pieces 32A, 32B) and the size of the contact area of the gap 34 relative to the pole face F2. On the other hand, although not shown in the figure, it is known that when the magnet angle θ exceeds 61.28°, depending on the shape of the magnet 32 (magnet pieces 32A, 32B) or the size of the contact area of the gap 34 relative to the pole face F2, the reduction rate of iron loss may sometimes be less than the reduction rate of the total torque. Therefore, it is preferred that the magnet angle θ is less than 61.28°.
[0047] [Modifications]
[0048] (Variant 1)
[0049] Figure 5 So with Figure 2 The same viewpoint shows a schematic diagram of the rotor 14 of Modification 1. Figure 5 In the embodiment, the same reference numerals are given to the same components as those described in the above embodiment. In addition, in this modification, the description overlapping with the above embodiment is omitted.
[0050] In this modified example, when the rotor core 30 is viewed from the direction of the central axis AX of the rotor core 30, the pair of magnet pieces 32A and 32B are arranged in a V-shape in such a manner that the distance between them becomes wider toward the outer periphery of the rotor core 30. The pair of magnetic pole faces F1 and F2 of the magnet piece 32A and the pair of magnetic pole faces F1 and F2 of the magnet piece 32B are not parallel, and the magnetic pole faces F1 and F2 are inclined in such a manner that they approach the outer periphery of the rotor core 30 toward the circumferential direction of the rotor core 30.
[0051] By arranging the pair of magnet pieces 32A and 32B in a V-shape in this manner, the iron loss can be further reduced compared to a case where the magnetic pole faces F1 and F2 of the pair of magnet pieces 32A and 32B are parallel.
[0052] (Variant 2)
[0053] Figure 6 So with Figure 2 The same viewpoint shows a schematic diagram of the rotor 14 of Modification 2. Figure 6 In the embodiment, the same reference numerals are given to the same components as those described in the above embodiment. In addition, in this modification, the description overlapping with the above embodiment is omitted.
[0054] In the above embodiment, the magnets 32 of the plurality of poles are divided, but they may be undivided as in this modification. In the case where the magnets 32 of the plurality of poles are undivided, the magnets 32 each have a pair of magnetic pole faces F1 and F2 located in a direction intersecting with the radial direction of the rotor core 30. In this case, the plurality of gaps 34 are provided corresponding to each of the magnets 32 of the plurality of poles. That is, the number of gaps is the number of poles, and the plurality of gaps 34 are surrounded by the rotor core 30 and the magnets 32, respectively.
[0055] The plurality of gaps 34 are in contact with the entirety of the magnetic pole surface F2 on the central axis AX side of the rotor core 30, except for the region in contact with the support member 30S. The support member 30S is a pair of protrusions protruding from the rotor core 30 toward the gap 34 side with the gap 34 interposed therebetween, and supports each of the magnets 32 of the plurality of poles.
[0056] In this way, even if the magnets 32 of the plurality of poles are respectively non-divided, the same effect as the above-mentioned embodiment can be obtained. In addition, in this modified example, a pair of magnetic pole faces F1 and F2 are curved surfaces, but they can also be flat surfaces. That is, as long as the magnets 32 of the plurality of poles are respectively plate-shaped, their specific shapes are not particularly limited. The shapes of the magnet pieces 32A and 32B are also the same.
[0057] [Inventions that can be obtained from the embodiments]
[0058] Hereinafter, the invention that can be grasped from the above-mentioned embodiment and modified examples will be described.
[0059] (First Invention)
[0060] The first invention is a rotor (14) characterized by comprising:
[0061] A rotor core (30);
[0062] a plate-shaped multi-pole magnet (32) disposed on the rotor core (30) with a pair of magnetic pole faces (F1, F2) located in a direction intersecting the radial direction of the rotor core (30); and
[0063] A plurality of gaps (34) are formed on the rotor core (30) and are in contact with the magnetic pole faces (F2) of the magnets (32) of the plurality of poles, which are close to the central axis (AX) of the rotor core (30).
[0064] As a result, it is possible to suppress the reduction in torque constant as much as possible and reduce iron loss without increasing the gap between the stator (12) and the rotor (14).
[0065] Each of the plurality of gaps (34) may be in contact with the entirety of the magnetic pole surface (F2) on the side close to the central axis (AX) of the rotor core (30) except for the region in contact with the support member (30S). Thus, compared with a case where the gaps (34) are in contact with the entirety of the magnetic pole surface (F2) except for the region in contact with the support member (30S), the iron loss can be further reduced.
[0066] Alternatively, for any of the magnets (32) of the plurality of poles, when the rotor core (30) is viewed from the axial direction of the central axis (AX) of the rotor core (30), an angle (θ) between two straight lines obtained by connecting two vertices (P1, P2) of the magnet (32) of one pole that are farthest from each other and close to the central axis (AX) of the rotor core (30) and the center of the rotor core (30) is smaller than a value obtained by dividing 360° by the number of poles of the magnet (32). Thus, the reduction rate of iron loss is easily increased compared with the reduction rate of torque constant.
[0067] The angle (θ) of any of the magnets (32) of multiple poles may be less than 61.28°. Thus, regardless of the size of the contact area of the gap (34) relative to the magnetic pole surface (F2), the reduction rate of iron loss can be greater than the reduction rate of the torque constant.
[0068] Alternatively, the magnets (32) of multiple poles are divided into a pair of magnet pieces (32A, 32B) whose magnetic poles are oriented in the same radial direction relative to the rotor core (30), and the multiple gaps (34) are connected to the magnetic pole faces (F2) of the magnet pieces (32A, 32B) obtained by the division, which are close to the central axis (AX) of the rotor core (30). Thus, compared with the case where the magnets 32 of multiple poles are not divided, the iron loss can be further reduced.
[0069] When the rotor core 30 is viewed from the axial direction of the central axis AX, the pair of magnet pieces 32A and 32B may be arranged in a V-shape in such a manner that the distance between them becomes wider toward the outer periphery of the rotor core 30. Thus, compared with the case where the magnetic pole faces (F1 and F2) of the pair of magnet pieces (32A and 32B) are parallel, the iron loss can be further reduced.
[0070] (Second Invention)
[0071] A second invention is a motor (10) comprising the rotor (14) and the stator (12). In the motor (10), since the rotor (14) is included, the gap between the stator (12) and the rotor (14) is not widened, and a decrease in the torque constant can be minimized, and iron loss can be reduced.
Claims
1. A rotor, characterized in that: have: Rotor core; a plate-shaped multi-pole magnet provided on the rotor core with a pair of magnetic pole faces positioned in a direction intersecting with a radial direction of the rotor core; and a plurality of gaps formed on the rotor core and in contact with the magnetic pole faces of the magnets of the plurality of poles on the side close to the central axis of the rotor core; For any one of the magnets with multiple poles, when the rotor core is observed axially from the center axis of the rotor core, the angle between each of the two vertices of the magnet connected to one pole that are farthest from each other on the side close to the center axis of the rotor core and two straight lines obtained from the center of the rotor core is smaller than the value obtained by dividing 360° by the number of poles of the magnet.
2. The rotor according to claim 1, characterized in that Each of the plurality of gaps is in contact with the entirety of the magnetic pole surface on the side close to the central axis of the rotor core except for a region with which the support member contacts.
3. The rotor according to claim 1, characterized in that The angle of any one of the magnets of a plurality of poles is less than 61.28°.
4. The rotor according to any one of claims 1 to 3, characterized in that: Each of the magnets of the plurality of poles is divided into a pair of magnet pieces whose magnetic poles are oriented in the same direction with respect to the radial direction of the rotor core. The plurality of gaps are in contact with the magnetic pole surface of each of the divided magnet segments on a side close to the central axis of the rotor core.
5. The rotor according to claim 4, characterized in that When the rotor core is viewed in the axial direction of the central axis, the pair of magnet pieces are arranged in a V-shape so that the intervals therebetween become larger toward the outer circumference of the rotor core.
6. A motor, characterized in that: have: The rotor and stator according to any one of claims 1 to 5.
Citation Information
Patent Citations
Method for manufacturing rotor and cutting apparatus
WO2012157107A1
Rotor for dynamo-electric machine, and dynamo-electric machine
WO2018168226A1