Motor, motor magnet separating method, and method for reusing motor magnet

Abstract

The present invention provides a motor in which magnets can be easily separated. Provided is a SPM motor comprising, a stator, a rotor that is disposed inside of the stator and has an iron core, a shaft that is disposed at the center of the rotor, and permanent magnets that are disposed on the surface of the iron core. The iron core is provided with permanent magnet-facing holes that face the permanent magnets.

Description

Motor, method for separating magnet of motor, and method for reusing magnet of motor ,

[0010]

[0001] The present invention relates to a motor, a method for separating a magnet of the motor, and a method for reusing the magnet of the motor.

[0002] Motors are widely used as indispensable devices in modern society. Various structures are known. Among them, there is a structure called a PM (Permanent_Magnet) motor in which a permanent magnet is provided on a rotor. An example of a PM motor is disclosed in Patent Document 1.

[0003] JP-A-2021-72733

[0004] In Patent Document 1, it is disclosed that a permanent magnet 13 is embedded in a rotor, and a cooling gas passage 9 is provided between the shaft 4 and the permanent magnet 13 in the rotor.

[0005] Here, since motors are widely used as indispensable devices in modern society, the number of motors discarded after use is extremely large. From the viewpoints of environmental protection in recent years and the availability of rare earth elements used in magnets, it has become important to facilitate the disassembly of motors. In particular, a motor structure in which magnets can be easily separated and a method for separating the magnets of a motor considering the reuse of the magnets are desired. <​​​​​​​​​​​​Further means and effects of the present invention will become apparent throughout the entire specification below.

[0011] This is a conceptual diagram of an SPM motor. This is a schematic cross-sectional structure of an example rotor. This is a schematic cross-sectional structure of an example rotor. This is a schematic cross-sectional structure of an example rotor. This is an explanatory diagram showing the magnetic circuit of the rotor. This is a conceptual diagram of a wedge jig. This is an explanatory diagram of the initial state using a wedge jig. This is an explanatory diagram of the intermediate state using a wedge jig. This is an explanatory diagram of the final state using a wedge jig. This is an explanatory diagram of the notched part of the rotor. This is a schematic cross-sectional view of an example of a sheet metal core. This is a schematic cross-sectional view showing the structure when a sheet metal core is laminated. This is a schematic front view of an example of a sheet metal core. This is a schematic front view of an example of a sheet metal core. This is a schematic front view of an example of a sheet metal core. This is a flowchart related to the separation of the motor's magnets.

[0012] Embodiments of the present invention will be described below with reference to the drawings.

[0013] Figure 1 is a conceptual diagram of a PM (Permanent Magnet) motor. The rotor 2 is positioned inside the stator 1. The rotor 2 has a shaft 5 at its center, which serves as the axis of rotation. Although not shown in the figure, a gap exists between the stator 1 and the rotor 2 to allow rotation. Coils forming electromagnets are also provided on the inside of the stator 1. This is the structure of a typical SPM motor, so it is not shown in the figure.

[0014] Figure 2 shows a schematic cross-sectional structure of an example of a rotor. The structure of rotor 2 will be explained using Figure 2. One of the features of the present invention lies in the structure of this rotor 2. Permanent magnets 20A for one pole and permanent magnets 20B for the other pole are sequentially arranged on the surface of rotor 2. This may also be referred to as the surface of the rotor core 10. One of the poles is the south pole and the other is the north pole.

[0015] As shown, permanent magnets are attached to the surface of the rotor. Motors with this type of attachment or surface arrangement are called SPM (Surface Permanent Magnet) motors.

[0016] A key feature of the SPM motor in this embodiment is that it has permanent magnet opposing holes 30.

[0017] The permanent magnet opposing holes 30 are shaped such that the direction in which the hole narrows faces the permanent magnet, with respect to the permanent magnet 20A of one pole and the permanent magnet 20B of the other pole. One example is a triangular shape. Note that even if the vertices are acute angles, this also includes cases where the hole has curvature, roundness, or a curve. Furthermore, any shape other than a triangle in which the hole narrows toward the permanent magnet is included in the category of permanent magnet opposing holes 30. The name "permanent magnet opposing hole" is established based on this aspect of the hole narrowing toward the permanent magnet.

[0018] The permanent magnet opposing hole 30 may be triangular in shape, or it may be an inverted teardrop shape that tapers towards the end, an arc shape that tapers towards the end, or a triangular shape with rounded ends. In all cases, the direction in which the hole narrows faces the side of the permanent magnet.

[0019] Furthermore, Patent Document 1 also discloses a cooling gas passage 9, which is a hole. However, this hole has approximately the same width or size on both the permanent magnet side and the opposite side. In other words, such a hole is not included in the permanent magnet opposing holes.

[0020] Figure 2 discloses a configuration in which there are three permanent magnets 20A for one pole and three permanent magnets 20B for the other pole, for a total of six poles. However, the number of poles is not particularly limited as long as it is an even number. When driving a motor, increasing the number of poles makes the rotation smoother, but the phase of the drive waveform supplied to the stator coil side becomes multiphase, which increases costs. Therefore, the number of poles is appropriately selected and designed according to the intended use of the motor and the allowable cost.

[0021] Figure 3 shows a schematic cross-sectional structure of an example rotor. The main difference from Figure 2 is the shape of the iron core 10. In Figure 2, it was circular, but in Figure 3, it is rectangular. The rectangular shape varies depending on the number of poles of the permanent magnet. For example, in the case of 4 poles, it will be quadrangular, and in the case of 6 poles, it will be hexagonal. As with Figure 2, there is no particular limit on the number of poles, but it is necessary to have at least 4 poles. For the purpose of simplifying the illustrations in the explanation, the following explanation will use the case of 4 poles or a quadrangular iron core 10 as an example.

[0022] The difference between Figure 4 and Figure 3 is that the outer shapes of the permanent magnets 20A on one pole and 20B on the other pole are arc-shaped. This allows for the arrangement of larger permanent magnets when housing the rotor 2 in the stator 1, improving the efficiency of space utilization.

[0023] Both Figure 3 and Figure 4, like Figure 2, are characterized by having permanent magnet opposing holes 30.

[0024] Figure 5 is an explanatory diagram showing the magnetic circuit of the rotor. For illustrative purposes, it is shown as a representative example in the lower right of Figure 3.

[0025] Magnetic field lines 50 are formed between one pole permanent magnet 20A located on the lower side of the rotor 2 and the other pole permanent magnet 20B located on the right side of the rotor 2, via the iron core 10. These magnetic field lines generate a rotational driving force in relation to the electromagnets formed by the coils of the stator 1.

[0026] Here, as shown in Figure 5, the magnetic field lines 50 are formed in a way that minimizes interference from the permanent magnet opposing holes 30. This shape of magnetic field lines is achieved, firstly, by positioning the permanent magnet opposing holes 30 in the center of the direction of extension of the permanent magnet. Secondly, it is achieved by having a permanent magnet opposing hole 30 that becomes smaller on the side facing the permanent magnet. Figure 5 shows that the shape and position of the permanent magnet opposing holes 30 are set to combine both of these structures. This makes it possible to avoid or suppress the influence on the magnetic circuit even when the permanent magnet opposing holes 30 are present.

[0027] Next, we will explain how to use the permanent magnet opposing holes 30, as described in Figures 2 to 5.

[0028] Figure 6A is a conceptual diagram of the wedge jig. The wedge jig 70 is configured such that the upper surface 70B is larger than the lower surface 70A of the wedge jig. Its shape is such that, in each cross-section, it is similar to the shape of, for example, the permanent magnet opposing hole 30.

[0029] Next, the separation of permanent magnets using a wedge jig will be explained with reference to Figures 6B to 6D.

[0030] Figure 6B is an explanatory diagram of the initial state when using a wedge jig. The example will be explained using the case where it is applied to the lower part of Figure 4. The wedge jig 70 is inserted into the permanent magnet opposing hole 30 from the lower surface 70A of the wedge jig.

[0031] Next, the wedge jig 70 is pressed down from above in the diagram and pushed into the permanent magnet opposing hole 30. Figure 6C is an explanatory diagram of the intermediate state when the wedge jig is used. The pushed-in wedge jig 70 applies pressure or force that causes the permanent magnet opposing hole 30 to spread outwards from the surrounding iron core 10. As a result, deformation or cracks 71 occur.

[0032] Furthermore, the wedge jig 70 is pressed down from above in the diagram and pushed into the permanent magnet opposing hole 30. Deformation and cracking 71 progress. Figure 6D is an explanatory diagram of the final state when the wedge jig is used. As a result of pressing down from above in the diagram and pushing the wedge jig 70 into the permanent magnet opposing hole 30, the iron core 10 ultimately deforms in the deformed part 72 so that it spreads outwards. This deformation results in the permanent magnet being pulled away from the iron core 10.

[0033] The wedge jig 70 can also be simply called a jig. However, if the jig has a shape similar to or comparable to the shape of the permanent magnet opposing hole 30, and is larger from the bottom to the top, then simply pushing it in will apply a force to expand the permanent magnet opposing hole 30. For this reason, it is a desirable shape in practical terms.

[0034] However, this also includes cases in which a jig with a shape that is not similar or not analogous is inserted into the permanent magnet opposing hole 30, and pressure is applied to the permanent magnet opposing hole 30 on the permanent magnet side by the jig using the principle of leverage, thereby deforming the permanent magnet opposing hole 30.

[0035] In this way, with an SPM motor, the separation of the permanent magnet from the iron core can be achieved in a simple and highly productive manner by simply pressing the wedge jig 70 into the permanent magnet opposing hole 30.

[0036] Furthermore, this is not solely due to the effect of pressing, but also largely due to the shape of the permanent magnet opposing hole 30. Specifically, the permanent magnet opposing hole 30 is shaped so that the permanent magnet side is smaller, making it possible to concentrate the stress from the wedge jig 70 on the permanent magnet side. This makes the iron core 10 more easily deformable on the permanent magnet side.

[0037] Furthermore, it is desirable that the wedge jig 70 be made of a material with a higher hardness than the iron core 10. This is to concentrate the deformation on the iron core 10 side.

[0038] As described above, by providing permanent magnet opposing holes 30 in the iron core 10 of the rotor 2, an SPM motor can be realized that allows for easy separation of the permanent magnets. Furthermore, by pressurizing and inserting a wedge jig 70 into the permanent magnet opposing holes 30, a method for separating the magnets of a motor that allows for easy separation of the permanent magnets can be provided.

[0039] Furthermore, for the purpose of inducing deformation early, it is desirable that the distance between the permanent magnet side end of the permanent magnet-facing hole 30 and the permanent magnet is 1 / 4 or less of the distance from the center of the iron core to the permanent magnet.

[0040] However, if the end of the permanent magnet-facing hole 30 on the permanent magnet side is too close to the permanent magnet, it becomes difficult to secure a sufficient amount of deformation of the iron core for separating the permanent magnet. For this reason, it is desirable that the distance between the end of the permanent magnet-facing hole 30 on the permanent magnet side and the permanent magnet is 1 / 50 or more of the distance from the center of the iron core to the permanent magnet.

[0041] This embodiment is basically the same as Embodiment 1. The difference is that this embodiment has a cut portion or a micro-hole portion in a part of the iron core from the end of the permanent magnet facing hole 30 to the permanent magnet.

[0042] FIG. 7 is an explanatory diagram of the cut portion of the rotor.

[0043] The cut portion 90 is provided in a part of the iron core from the end of the permanent magnet facing hole 30 to the permanent magnet. One or more micro-hole portions 91 are provided in the cut portion 90. The micro-hole portion 91 is provided to more quickly realize the deformation of the iron core 10. Therefore, it is desirable that the cut portion 90 or the micro-hole portion 91 be arranged to extend linearly from the end of the permanent magnet facing hole 30. Also, when there are a plurality of micro-hole portions 91, it is desirable that they be arranged linearly.

[0044] An example of a specific configuration method of the cut portion 90 or the micro-hole portion 91 will be described using FIGS. 8A to 8E.

[0045] FIG. 8A is a schematic cross-sectional view of an example of the iron core plate material. A micro-hole portion 101 with a reduced wall thickness in the middle is provided in a part of the iron core plate material 100. The iron core plate material 100 is provided with the micro-hole portion 101 while leaving the wall thickness. Also, in the figure, the micro-hole portion 101 is formed in a V shape so that its tip faces the permanent magnet side. Thereby, at the cut portion 90, its tip faces the permanent magnet side.

[0046] FIG. 8B is a schematic cross-sectional view showing the structure during lamination of an example of the iron core plate material. By laminating the iron core plate materials 100 of FIG. 8A, a large number of micro-hole portions 101 are configured to overlap.

[0047] FIG. 8C is a schematic front view of an example of the iron core plate material. It is a view when FIG. 8A or FIG. 8B is seen from the front.

[0048] Also, various shapes are possible for the cut portion 90 or the micro-hole portion 91.

[0049] Figure 8D is a schematic front view of an example of a sheet metal core. The micro-holes 101 are configured as completely through holes. Instead, in order to maintain the function of the core, the sheet metal 100 of the core remains intact between adjacent micro-holes 101 in the vertical direction shown in the figure. In other words, the holes do not penetrate vertically, but are configured discontinuously or intermittently.

[0050] Figure 8E is a modified version of Figure 8D, in which the minute hole portion 101 is rectangular in Figure 8D, whereas in Figure 8E it is circular.

[0051] By stacking multiple iron core plate materials 100 as shown in Figures 8C to 8E in the extending direction of the shaft 5, the notches 90 and minute holes 91 shown in Figure 7 can be easily formed.

[0052] As described above, by providing a notch or a micro-hole in a part of the iron core from the end of the permanent magnet opposing hole 30 to the permanent magnet, in addition to the effects of Embodiment 1, it is possible to further facilitate the separation of the magnet from the rotor.

[0053] This embodiment is a flowchart illustrating the process of separating the permanent magnets from the rotor, based on the rotor structure of either Embodiment 1 or Embodiment 2. Figure 9 shows a flowchart related to the separation of the motor magnets.

[0054] In step S1, a wedge jig is inserted into the hole opposite the permanent magnet. In step S2, the wedge jig is pushed in and lowered. In step S3, as a result of the rotor deformation, the permanent magnet detaches and separates.

[0055] At this stage, the permanent magnet has been forcibly detached. Therefore, some adhesive used to bond the permanent magnet to the rotor's iron core may remain on it.

[0056] Therefore, if necessary, the adhesive is cleaned and removed in step S4.

[0057] If the sole purpose is the separation and recovery of the permanent magnet, the process can be terminated at step S4.

[0058] However, if the separated permanent magnets are to be attached to a new rotor and reused, then the next steps S5 and S6 are performed.

[0059] In step S5, adhesive is applied to the recovered permanent magnet and attached to the iron core of the new rotor. In step S6, the permanent magnet is remagnetized. If the recovered permanent magnet has sufficient magnetic force, step S6 may be omitted. Also, the order of steps S5 and S6 may be reversed for convenience in the manufacturing process.

[0060] As described above, this embodiment provides a method for separating magnets that can easily recover the permanent magnets of an SPM motor. Furthermore, it provides a method for reusing the recovered magnets.

[0061] Each of the embodiments described above can be used individually or in combination.

[0062] Furthermore, insofar as the above-described technical concept is applied, variations and equivalents are also included within the scope of the description in this specification.

[0063] Furthermore, an example of the present invention described using the above embodiments can also be expressed as follows.

[0064] <1> An SPM motor having a stator, a rotor having an iron core disposed inside the stator, and a shaft disposed at the center of the rotor, wherein the iron core has permanent magnets disposed on the surface of the iron core, wherein the iron core has permanent magnet opposing holes facing the permanent magnets. <2> The SPM motor according to <1>, wherein the permanent magnet opposing holes have a shape in which the holes become smaller toward the permanent magnets. <3> The SPM motor according to <2>, wherein the permanent magnet opposing holes are arranged corresponding to the central part of the permanent magnets. <4> The SPM motor according to <3>, wherein the permanent magnet opposing holes have a triangular shape, with one of the vertices positioned opposite the permanent magnets. <5> The SPM motor according to <4>, wherein the distance from the end of the permanent magnet-side of the permanent magnet opposing hole to the permanent magnet is 1 / 4 or less of the distance from the center of the iron core to the permanent magnets. <6> The SPM motor according to <5> wherein the distance from the end of the permanent magnet-facing hole to the permanent magnet is 1 / 50 or more of the distance from the center of the core to the permanent magnet. <7> The SPM motor according to <2> wherein the core has a notch or a micro-hole in the region between the permanent magnet-facing hole and the permanent magnet. <8> The SPM motor according to <7> wherein the notch or micro-hole has a plurality of notches or holes. <9> The SPM motor according to <8> wherein the notch or micro-hole is configured by stacking plate material having notches in the direction of extension of the shaft. <10> The SPM motor according to <8> wherein the notch or micro-hole is configured by stacking plate material having holes in the direction of extension of the shaft. <No. 11> A method for separating the magnets of a motor having an iron core and permanent magnets attached to the surface of the iron core, wherein the iron core has permanent magnet opposing holes that face the permanent magnets, and a jig is inserted and pressed into the permanent magnet opposing holes to deform the iron core and separate the permanent magnets from the iron core. <No. 12> The method for separating the magnets of a motor according to <No. 11>, wherein the jig is similar in shape to the permanent magnet opposing holes and is shaped to increase from the bottom surface to the top surface.<Method 13> A method for reusing motor magnets, wherein after separating the permanent magnets using the method for separating motor magnets described in <Method 12>, the adhesive on the permanent magnets is washed and removed, and then the permanent magnets are attached to a new iron core with adhesive. <Method 14> A method for reusing motor magnets as described in <Method 13>, wherein the permanent magnets are remagnetized either before or after attaching the permanent magnets to the iron core with adhesive.

[0065] 1: Stator 2: Rotor 5: Shaft 10: Rotor core 20A: Permanent magnet of one polarity 20B: Permanent magnet of the other polarity 30: Hole opposite permanent magnet 50: Magnetic field lines 70: Wedge jig 70A: Bottom surface of wedge jig 70B: Top surface of wedge jig 71: Crack 72: Deformed part 90: Notch 91: Microhole 100: Iron core plate 101: Microhole

Claims

1. An SPM motor having a stator, a rotor disposed inside the stator and having an iron core, and a shaft disposed at the center of the rotor, wherein the iron core has permanent magnets disposed on the surface of the iron core, the SPM motor having permanent magnet facing holes that face the permanent magnets.

2. The SPM motor according to claim 1, wherein the hole opposite the permanent magnet has a shape that becomes smaller when it faces the permanent magnet.

3. The SPM motor according to claim 2, wherein the permanent magnet opposing holes are arranged corresponding to the central portion of the permanent magnet.

4. The SPM motor according to claim 3, wherein the hole opposite the permanent magnet has a triangular shape, and one of its vertices is positioned opposite the permanent magnet.

5. The SPM motor according to claim 4, wherein the distance from the end of the permanent magnet-facing hole to the permanent magnet is 1 / 4 or less of the distance from the center of the iron core to the permanent magnet.

6. The SPM motor according to claim 5, wherein the distance from the end of the permanent magnet-facing hole to the permanent magnet is 1 / 50 or more of the distance from the center of the iron core to the permanent magnet.

7. The SPM motor according to claim 2, wherein the iron core has a notch or a micro-hole in the region between the permanent magnet opposing hole and the permanent magnet.

8. The SPM motor according to claim 7, wherein the notched portion or the minute hole portion has a plurality of notches or holes.

9. The SPM motor according to claim 8, wherein the notched portion or the minute hole portion is configured by stacking plate material having notches in the direction of extension of the shaft.

10. The SPM motor according to claim 8, wherein the notched portion or the minute hole portion is configured by stacking plate material having holes in the direction of extension of the shaft.

11. A method for separating the magnets of a motor having an iron core and permanent magnets attached to the surface of the iron core, wherein the iron core has permanent magnet opposing holes that face the permanent magnets, and a jig is inserted and pressed into the permanent magnet opposing holes to deform the iron core and separate the permanent magnets from the iron core.

12. The method for separating the magnets of a motor according to claim 11, wherein the jig has a shape similar to the permanent magnet opposing hole and is larger from the bottom surface to the top surface.

13. A method for reusing motor magnets, comprising separating the permanent magnets using the method for separating motor magnets described in claim 12, cleaning and removing the adhesive from the permanent magnets, and then attaching the permanent magnets to a new iron core with adhesive.

14. A method for reusing the magnets of a motor according to claim 13, wherein the permanent magnets are remagnetized in a step before or after attaching the permanent magnets to the iron core with an adhesive.

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