Recovery device for permanent magnets and recovery method for permanent magnets

Abstract

The present invention provides a permanent magnet recovery device and a permanent magnet recovery method that can recover a permanent magnet mounted on a laminated steel sheet having an insulating film via a resin material without impairing the characteristics of the permanent magnet. To solve the above problem, the present invention provides a permanent magnet recovery device (1) including: a heat treatment furnace (2) that stores a permanent magnet holder (5) on which a permanent magnet (8) is mounted on a laminated steel sheet (6) having an insulating film via a resin material (7), a high-frequency absorber (10) being provided in at least a range in which the resin material (7) is in contact with both end portions in a laminating direction of the laminated steel sheet (6); and a microwave generation device (3) that radiates microwaves into the heat treatment furnace (2). In one aspect, the permanent magnet holder (5) is a rotor (9) of a specified rotary electric machine, and a high-frequency absorber (12) is further provided along an outer peripheral surface portion of the laminated steel sheet (6) of the rotor (9).

Description

Technical Field

[0001] The invention relates to a permanent magnet recovery device and a permanent magnet recovery method. Background Art

[0002] A technology has been proposed for disassembling a magnetic circuit structure composed of laminated steel plates with permanent magnets fixed to them with adhesive, such as in the rotor of a rotating electric machine, to recover the permanent magnets (see, for example, Patent Document 1). In the technology of Patent Document 1, the magnetic circuit structure is heated to a high temperature in a heavy oil furnace to carbonize the adhesive and recover the permanent magnets. Another technology has been proposed for increasing the temperature of laminated steel plates coated with an adhesive film by microwave heating to enhance the adhesive film's bonding strength (see, for example, Patent Document 2).

[0003] [Prior Art Literature]

[0004] (Patent Document)

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2001-85223

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 11-234972 Summary of the Invention

[0007] [Problems to be solved by the invention]

[0008] In the technology of Patent Document 1, the permanent magnets are deliberately rendered ineffective by heating the magnetic circuit structure to a high temperature in a heavy oil furnace so that they can be safely recycled. On the other hand, since the expensive permanent magnets are recycled in a state where their original properties have been damaged, there is a significant loss from the perspective of resource recycling. On the other hand, the technology of Patent Document 2 is specifically used to strengthen the joints between laminated steel plates. Therefore, there is no perspective on recovering specific recycling objects such as permanent magnets from the magnetic circuit structure. Therefore, it cannot be directly applied to recycling purposes.

[0009] The present invention was developed in light of the above-mentioned circumstances, and its object is to provide a permanent magnet recovery device and method that can recover permanent magnets mounted on laminated steel plates with insulating films via resin materials without compromising their properties. If permanent magnets can be recovered without compromising their properties, they can be reused, thereby reducing the need to manufacture new permanent magnets and reducing environmental impacts such as carbon dioxide emissions.

[0010] [Technical means to solve the problem]

[0011] (1) A permanent magnet recycling device (e.g., the permanent magnet recycling device 1 described below) including: a heat treatment furnace (e.g., the heat treatment furnace 2 described below), a permanent magnet holding body (e.g., the permanent magnet holding body 5 described below) in which a permanent magnet (e.g., the permanent magnet 8 described below) is mounted on a laminated steel sheet (e.g., the laminated steel sheet 6 described below) having an insulating film via a resin material (e.g., the resin material 7 described below), a high-frequency absorber (e.g., the high-frequency absorber 10 described below) provided in at least a range in contact with the resin material at both end portions in a stacking direction of the laminated steel sheet; and a microwave generating device (e.g., the microwave generating device 3 described below) that radiates microwaves into the heat treatment furnace.

[0012] (2) The permanent magnet recycling device according to the above (1), wherein the laminated steel sheet of the permanent magnet holding body has an outer peripheral surface portion, and a high-frequency absorber (e.g., the high-frequency absorber 12 described below) is further provided along the outer peripheral surface portion.

[0013] (3) The permanent magnet recycling device according to the above (1) or (2), wherein the permanent magnet holding body is a rotor (e.g., the rotor 9 described below) of a prescribed rotary electric machine.

[0014] (4) A permanent magnet recycling method including: a high-frequency absorber assembly process (e.g., the high-frequency absorber assembly process S1 described below) of assembling a high-frequency absorber (e.g., the high-frequency absorber 10 described below) on a permanent magnet holding body (e.g., the permanent magnet holding body 5 described below) in which a permanent magnet (e.g., the permanent magnet 8 described below) is mounted on a laminated steel sheet (e.g., the laminated steel sheet 6 described below) having an insulating film via a resin material (e.g., the resin material 7 described below) and in at least a range in contact with the resin material at both end portions in a stacking direction of the laminated steel sheet; and a microwave heating process (e.g., the microwave heating process S2 described below) of heating the permanent magnet holding body on which the high-frequency absorber is assembled in the high-frequency absorber assembly process with a microwave heating furnace (e.g., the microwave heating furnace 4 described below).

[0015] (5) The permanent magnet recycling method according to the above (4), wherein, in the high-frequency absorber assembly process, a high-frequency absorber (e.g., the high-frequency absorber 12 described below) is further provided along an outer peripheral surface portion of a laminated steel sheet (e.g., the laminated steel sheet 6 described below) of the permanent magnet holding body having the outer peripheral surface portion.

[0016] (6) The permanent magnet recycling method according to the above (4) or (5), wherein the permanent magnet holding body is a rotor (e.g., the rotor 9 described below) of a prescribed rotary electric machine.

[0017] (Effects of the Invention)

[0018] In the permanent magnet recovery device of (1), since high-frequency absorbers are provided at the portions of the laminated steel plates in contact with the resin material at both ends in the stacking direction, the ends of the laminated steel plates, which are difficult to heat with microwaves, can be efficiently heated, thereby shortening the heating time required for recovering the permanent magnets. As a result, the permanent magnets can be recovered without compromising their properties, thereby reducing the need to manufacture new permanent magnets and, in turn, reducing carbon dioxide emissions and other environmental impacts.

[0019] In the permanent magnet recovery device of (2), since a high-frequency absorber is further provided along the outer peripheral surface of the laminated steel plates, heat can be transferred to the resin material from the outer peripheral surface side, thereby enabling more efficient heating.

[0020] In the permanent magnet recovery device of (3), since the permanent magnets can be recovered from the rotor of a rotating electrical machine using many high-performance permanent magnets without damaging the properties of the permanent magnets, the recovered permanent magnets are suitable for recycling.

[0021] In the permanent magnet recovery method of (4), since high-frequency absorbers are provided at the portions of the laminated steel plates in contact with the resin material at both ends in the stacking direction, the ends of the laminated steel plates, which are difficult to heat with microwaves, can be efficiently heated, thereby shortening the heating time required to recover the permanent magnets. As a result, the permanent magnets can be recovered without compromising their properties, thereby reducing the need to manufacture new permanent magnets and, in turn, reducing carbon dioxide emissions and other environmental impacts.

[0022] In the permanent magnet recovery method of (5), since a high-frequency absorber is further provided along the outer peripheral surface of the laminated steel plate, heat can be transferred to the resin material from the outer peripheral surface side, thereby enabling more efficient heating.

[0023] In the permanent magnet recovery method of (6), since the permanent magnets can be recovered from the rotor of a rotating electrical machine using a large number of high-performance permanent magnets without damaging the properties of the permanent magnets, the recovered permanent magnets are suitable for recycling. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a conceptual diagram illustrating a permanent magnet recovery device according to an embodiment of the present invention.

[0025] Figure 2 It is a diagram illustrating a high-frequency absorber assembly process in a permanent magnet recovery method according to an embodiment of the present invention.

[0026] Figure 3 is a process diagram of a recycling method of a permanent magnet of an embodiment of the present application.

[0027] Figure 4 is a drawing that explains other patterns in an embodiment of the present application.

[0028] Figure 5 is a drawing that explains an effect related to an embodiment of the present application.

[0029] Figure 6 is a drawing that illustrates an object of an experiment performed in association with the present application.

[0030] Figure 7 is a drawing that illustrates an object of an experiment performed in association with the present application. Figure 6 is a drawing that illustrates an experimental result related to an object of the present application. DETAILED DESCRIPTION

[0031] Next, an embodiment of the present application will be described with reference to the drawings. In each drawing shown below, the same symbols are attached to the same parts or corresponding parts. Figure 1 is a conceptual drawing that illustrates a recycling device 1 of a permanent magnet of an embodiment of the present application. Figure 2 is a drawing that explains a high-frequency absorber assembly process in a recycling method of a permanent magnet of an embodiment of the present application. Figure 3 is a process diagram of a recycling method of a permanent magnet of an embodiment of the present application.

[0032] The recycling device 1 of a permanent magnet of an embodiment of the present application has a heat treatment furnace 2 for heating a processed material, and a microwave generating device 3 that radiates microwaves into the heat treatment furnace 2. The microwave generating device 3 is constituted by a magnetron and a waveguide tube, or the like. A microwave heating furnace 4 is constituted by the heat treatment furnace 2 and the microwave generating device 3. The recycling device 1 of a permanent magnet is in a state in which the heat treatment furnace 2 of the microwave heating furnace 4 stores a processed material that is a specific permanent magnet holder 5 as a heating object.

[0033] The permanent magnet holder 5 is installed with a permanent magnet 8 on a laminated steel sheet 6 having an insulating film via a resin material 7, and is, for example, a rotor 9 of a disassembled rotating electric machine. Such a rotor 9 is a rotor of a permanent magnet embedded type, and is also called an Interior Permanent Magnet (IPM) rotor. A plurality of rare-earth magnets of high performance and high price are held on the IPM rotor.

[0034] As Figure 2As shown in FIG, high-frequency absorbers 10 are mounted at predetermined locations on rotor 9, which serves as permanent magnet holder 5. In this example, high-frequency absorbers 10 are mounted on permanent magnet holder 5 within the range of at least the ends of laminated steel plates 6 in the stacking direction, where they come into contact with resin material 7. As a result, rotor 9 has a first form of processed material 11, in which high-frequency absorbers 10 are mounted in respective regions of the peripheral edge portions of both axial end surfaces of the rotor 9.

[0035] like Figure 3 As shown in FIG, the permanent magnet recovery method according to the embodiment of the present invention includes a high-frequency absorber assembly step S1 and a microwave heating step S2. The high-frequency absorber assembly step S1 is to Figure 2 The rotor 9 is formed into the shape of the first form of the material to be processed 11. Then, in the microwave heating step S2, the first form of the material to be processed 11 is stored in the heat treatment furnace 2 of the microwave heating furnace 4 and heated by microwaves from the microwave generator 3.

[0036] In the high-frequency absorber assembly step S1, a cylindrical high-frequency absorber 12 may be further assembled around the outer peripheral surface of the laminated steel plates 6 of the first-form material to be processed 11, thereby forming a second-form material to be processed 13. Furthermore, in the high-frequency absorber assembly step S1, a plurality of plate-shaped high-frequency absorbers 14 may be assembled around the outer peripheral surface of the laminated steel plates 6 of the first-form material to be processed 11, thereby forming a third-form material to be processed 15.

[0037] Figure 5 Schematic diagram showing the process of heating the material to be treated in the heat treatment furnace 2 of the microwave heating furnace 4. Figure 5 The material to be processed is the portion of the laminated steel plates 6 with insulating films and the resin material 7 holding the permanent magnets 8 in the rotor 9 of the rotating electrical machine. Figure 5 In the figure, the material to be processed is designated by reference numeral 16. Material to be processed 16 corresponds to the laminated steel sheets 6 in rotor 9 and constitutes a laminate 19 composed of electromagnetic steel sheets 18 laminated with insulating layers 17 interposed therebetween. Adhesive 20 corresponding to the resin material 7 holding the permanent magnets 8 in rotor 9 of the rotating electrical machine is adhered to the side ends of laminate 19 along the lamination direction. Microwaves 21 are projected onto material to be processed 16.

[0038] From the initial first stage P1, when microwaves 21 begin projecting onto the material 16 being processed, microwaves 21 are reflected by the electromagnetic steel sheet 18, which is a metal plate, but then propagate through the insulating layer 17 to the adhesive 20. In the subsequent second stage P2, a high-temperature region 22, heated by microwaves 21, begins to expand in the center of the adhesive 20. In other words, the adhesive 20 begins to heat from the center.

[0039] As the temperature of the adhesive 20 further rises, it softens and expands, reaching the third stage P3, where the gap 23 between the electromagnetic steel sheets 18 widens. At the third stage P3, a large potential difference appears across the gap 23. Soon, the state reaches the fourth stage P4, where insulation breakdown occurs across the gap 23, causing sparks 24 to fly. In the fourth stage P4, the electromagnetic steel sheets 18 are heated by the sparks 24.

[0040] Even in the fourth stage P4, even if a high-temperature region 22 appears in the center of the adhesive 20, the temperature does not rise to the surrounding areas near the ends of the electromagnetic steel sheets 18 in the stacking direction. In contrast, if the high-frequency absorber 10 is attached to the areas containing the adhesive 20 at the ends of the electromagnetic steel sheets 18 in the stacking direction, the high-frequency absorber 10 is heated by the microwaves 21, and this heat is transferred to the adhesive 20. As a result, the high-temperature region 22 expands to cover substantially the entire interior of the adhesive 20, reaching the optimal stage Pm, where optimal heating is achieved. In the optimal stage Pm, the temperature of the localized area of ​​the material being processed 16, namely the adhesive 20 area, is selectively raised, causing its adhesive strength to fail, allowing easy removal of the permanent magnet. In this case, since the permanent magnet is not significantly heated, it can be recovered without compromising its properties as a permanent magnet.

[0041] Next, refer to Figure 6 and Figure 7 , for confirmation Figure 5 The experimental results of the effect of Figure 6 The following figure shows a test piece 25 used in this experiment. Test piece 25 simulates a portion of a rotor of a rotating electrical machine. Test piece 25 is composed of a stack 19 of electromagnetic steel sheets 18 stacked with insulating layers 17 simulating the rotor's main body. Silicon carbide (SiC) plates are attached as high-frequency absorbers 10 to the upper and lower end faces in the stacking direction.

[0042] Figure 7 Therefore Figure 6 The temperature distribution inside the laminate 19 when microwaves were projected is generally shown in a time series observation by comparing the case where the high-frequency absorber 10 was removed from the test piece 25 with the case where the high-frequency absorber 10 was attached. Figure 7 In the graph, the area with higher density of points has higher temperature. Figure 7 The time series observations in which the microwaves are projected are related to each other, and the relationship between the time series observations and the microwaves is t1<t2<t3. Figure 7It was ascertained that, in both the case where the plate-shaped body of SiC was assembled and the case where the plate-shaped body of SiC was not assembled, the longer the elapsed time related to the projection of microwaves, the higher the temperature of the inside of the laminate 19 rose. However, in the case where the plate-shaped body of SiC was not assembled, even when the elapsed time related to the projection of microwaves reached t3, a temperature distribution in which the center portion of the inside of the laminate 19 was warmed up and a portion in which the periphery portion remained not so much warmed up remained. In contrast, in the case where the plate-shaped body of SiC was assembled, when the elapsed time related to the projection of microwaves reached t3, the inside of the laminate 19 was uniformly warmed up from the center portion to the periphery portion. It was ascertained from this experimental result that the assembly of the plate-shaped body of SiC as the high-frequency absorber 10 at both end portions in the stacking direction of the electromagnetic steel plate 18 was effective for the recovery of the permanent magnet 8 from the rotor 9 of the rotary electric machine, which was the permanent magnet holder 5 that held the permanent magnet 8 on the laminated steel plate 6 on which the electromagnetic steel plate 18 was laminated via the insulating layer 17.

[0043] The permanent magnet recovery device and the permanent magnet recovery method according to the present embodiment have the following effects.

[0044] In the permanent magnet recovery device 1 of (1), a heat treatment furnace 2 that stores a permanent magnet holder 5 in which a permanent magnet 8 is mounted on a laminated steel plate 6 having an insulating film via a resin material 7, and a high-frequency absorber 10 is provided in a range at least in contact with the resin material 7 at both end portions in the stacking direction of the laminated steel plate 6, and a microwave generation device 3 that radiates microwaves into the heat treatment furnace 2 are included. Thereby, the end portion side of the laminated steel plate that is difficult to heat with microwaves can be efficiently heated, and thus the heating time required for recovering the permanent magnet can be shortened. Therefore, the permanent magnet can be recovered without impairing its characteristics, and thus the opportunity to manufacture a new permanent magnet can be reduced, and further, the reduction of the amount of carbon dioxide emission and the reduction of the load on the environment can be achieved.

[0045] In the permanent magnet recovery device of (2), the laminated steel plate 6 of the permanent magnet holder 5 has an outer peripheral surface portion, and a high-frequency absorber 12 is further provided along the outer peripheral surface portion. Thereby, heat can be transferred to the resin material 7 also from the outer peripheral surface portion side, and thus heating can be performed more efficiently.

[0046] In the permanent magnet recovery device of (3), the permanent magnet holder 5 is a rotor 9 of a prescribed rotary electric machine. Since the permanent magnet 8 can be recovered from the rotor 9 of the rotary electric machine in which many high-performance permanent magnets 8 are used without impairing the characteristics of the permanent magnet 8, the recovered permanent magnet is suitable for a recycling use.

[0047] In the permanent magnet recovery method of (4), a high-frequency absorber assembly step S1 of assembling a high-frequency absorber 10 on the permanent magnet holding body 5, which mounts a permanent magnet 8 on a laminated steel sheet 6 having an insulating film via a resin material 7, in a range of at least the contact with the resin material 7 on both end portions of the laminated steel sheet 6 in the stacking direction, and a microwave heating step S2 of heating the permanent magnet holding body 5 assembled with the high-frequency absorber 10 in the high-frequency absorber assembly step S1 with a microwave heating furnace 4. Thus, the end portion side of the laminated steel sheet 6 that is difficult to heat with microwaves can be efficiently heated, and the heating time required to recover the permanent magnet 8 can be shortened. Therefore, the permanent magnet 8 can be recovered without impairing its characteristics, and the opportunity to manufacture a new permanent magnet can be reduced, and further, the reduction of the environmental load such as the amount of carbon dioxide emission can be achieved.

[0048] In the permanent magnet recovery method of (5), in the high-frequency absorber assembly step S1, a high-frequency absorber 12 is further provided along the outer peripheral surface portion of the laminated steel sheet 6 of the permanent magnet holding body 5 having an outer peripheral surface portion. Thus, heat can be transferred to the resin material 7 also from the outer peripheral surface portion side of the laminated steel sheet 6, and heating can be performed more efficiently.

[0049] In the permanent magnet recovery method of (6), the permanent magnet holding body 5 is a rotor 9 of a prescribed rotary electric machine. Since the permanent magnet 8 can be recovered from the rotor 9 of the rotary electric machine using many high-performance permanent magnets 8 without impairing the characteristics of the permanent magnet 8, the recovered permanent magnet is suitable for a recycling use.

[0050] The above describes the embodiments of the present application, but the present application is not limited thereto. Details can be appropriately changed within the scope of the gist of the present application. For example, in the above, an example in which the permanent magnet holding body is a rotor of a rotary electric machine and the permanent magnet is recovered from the rotor is described, but the present application can also be applied to a case in which the permanent magnet holding body is a medical instrument using a permanent magnet and the permanent magnet is recovered from the medical instrument.

[0051] Reference Signs

[0052] 1 Permanent magnet recovery device

[0053] 2 Heat treatment furnace

[0054] 3 Microwave generation device

[0055] 4 Microwave heating furnace

[0056] 5 Permanent magnet holding body

[0057] 6 Laminated steel sheet

[0058] 7 Resin material

[0059] 8 permanent magnet

[0060] 9 rotor

[0061] 10 high-frequency absorber

[0062] 11 first state of the material to be processed

[0063] 12 high-frequency absorber

[0064] 13 second state of the material to be processed

[0065] 14 high-frequency absorber

[0066] 15 third state of the material to be processed

[0067] 16 material to be processed

[0068] 17 insulating layer

[0069] 18 electromagnetic steel sheet

[0070] 19 laminate

[0071] 20 adhesive

[0072] 21 microwave

[0073] 22 high-temperature region

[0074] 23 gap

[0075] 24 electric spark

[0076] 25 test piece

Claims

1. A permanent magnet recovery device comprising: a heat treatment furnace storing a permanent magnet holder having permanent magnets mounted on laminated steel plates having an insulating film via a resin material, wherein high-frequency absorbers for absorbing microwaves and being heated are provided at least in a range in contact with the resin material at both ends of the laminated steel plates in a stacking direction; and The microwave generating device radiates microwaves into the heat treatment furnace.

2. The permanent magnet recovery device according to claim 1, wherein: The laminated steel plates of the permanent magnet holding body have an outer peripheral surface, and a high-frequency absorber is further provided along the outer peripheral surface.

3. The permanent magnet recovery device according to claim 1, wherein: The permanent magnet holder is a rotor of a predetermined rotating electrical machine.

4. A method for recovering permanent magnets, comprising: a high-frequency absorber mounting step of mounting the high-frequency absorber on a permanent magnet holder having permanent magnets mounted on the laminated steel plates having an insulating film via the resin material and within a range at least in contact with the resin material at both ends of the laminated steel plates in the stacking direction; and The microwave heating step is to heat the permanent magnet holder to which the high-frequency absorber is attached in the high-frequency absorber assembling step using a microwave heating furnace.

5. The method for recovering permanent magnets according to claim 4, wherein: In the high-frequency absorber mounting step, a high-frequency absorber is further provided along the outer peripheral surface of the laminated steel plates of the permanent magnet holder having the outer peripheral surface.

6. The method for recovering permanent magnets according to claim 4, wherein: The permanent magnet holder is a rotor of a predetermined rotating electrical machine.

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