Method for manufacturing a magnet and method for manufacturing a rotor

Abstract

To efficiently cut a sheet material covering a surface of a magnet body.SOLUTION: An intermediate body 88 in which a plurality of magnet bodies 82 are located on the same surface of a first sheet material 86A is prepared. Then, the intermediate body 88 is placed between a first mold 303 made from an elastic material having an elastic modulus smaller than that of the magnet bodies 82 and a second mold 304 facing the first mold 303. Then, the first mold 303 and the second mold 304 sandwich the intermediate body 88, whereby the first sheet material 86A is cut between the adjacently arranged magnet bodies 82.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] This invention relates to a method for manufacturing a magnet and a method for manufacturing a rotor.

Background Art

[0002] The rotor of the motor disclosed in Patent Document 1 has a rotor core and a plurality of magnets. The rotor core has a plurality of slots. The plurality of magnets are located in each slot.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As the magnet of the rotor as in Patent Document 1, a magnet having a sheet-like coating attached to the surface of the magnet body may be employed. However, it is time-consuming to cut one by one the sheet materials, which are the materials of the coatings, according to the shape of each magnet body. Therefore, a technique for efficiently cutting the sheet material for covering the surface of the magnet body is desired.

Means for Solving the Problems

[0005] A method for manufacturing a magnet for solving the above problems includes an intermediate body manufacturing step of manufacturing an intermediate body in which a plurality of magnet bodies are located on the same surface of a sheet material, and a first mold made of an elastic material having a smaller elastic modulus than the magnet body and a second mold facing the first mold. An arranging step of arranging the intermediate body such that the surface of the sheet material opposite to the side where the magnet body is located faces the first mold, and sandwiching the intermediate body between the first mold and the second mold, With the elastic deformation of the first type, and a cutting step of cutting the sheet material between the magnet bodies arranged adjacent to each other.

[0006] In the above configuration, in the cutting process, the first type elastically deforms so as to extend in the lateral direction and also elastically deforms so as to enter between adjacent magnet bodies. As a result, a force in a direction away from each other acts on the adjacent magnet bodies. Also, at the edges of each magnet body, the force from the elastically deformed first type tends to concentrate and act. Due to these results, the sheet material is cut between the adjacent magnet bodies. This cutting of the sheet material occurs at various locations of the adjacent magnet bodies during the cutting process. Therefore, the sheet material can be cut efficiently.

[0007] In the method for manufacturing a magnet, the magnet body has a planar first surface and a planar second surface adjacent to the first surface. In the intermediate body manufacturing process, a plurality of the magnet bodies may be arranged on the same surface of the sheet material such that the first surface contacts the sheet material.

[0008] According to the above configuration, when the first type is pressed against the intermediate body, a force is likely to be applied from the first type to the boundary between the first surface and the second surface in the magnet body. Therefore, it becomes easier to cut the sheet material at the above boundary.

[0009] In the method for manufacturing a magnet, the surface of the first type facing the sheet material has a planar flat surface and a protruding surface protruding from the flat surface. In the arranging process, the intermediate body may be arranged such that the boundary between the first surface and the second surface in the magnet body faces the protruding surface with the sheet material interposed therebetween.

[0010] According to the above configuration, when the first type is pressed against the intermediate body, a force is likely to act on the sheet material from the protruding surface of the first type. Specifically, a very strong force is applied to the portion of the sheet material sandwiched between the protruding surface of the first type and the boundary between the first surface and the second surface in the magnet body. Therefore, the sheet material can be cut more reliably at the said portion.

[0011] In the method for manufacturing a magnet, the sheet material contains thermoplastic resin fibers and inorganic fibers. In the intermediate body manufacturing step, while heating the sheet material to a temperature equal to or higher than the glass transition temperature of the thermoplastic resin fibers and applying pressure, the sheet material may be thermocompression bonded to a plurality of the magnet bodies in a state where the inorganic fibers are elastically compressed.

[0012] When a sheet material containing thermoplastic resin fibers and inorganic fibers is thermocompression bonded to a magnet body and then heated again, the thermoplastic resin fibers in the sheet material soften again, and the sheet material expands due to the action of the inorganic fibers that were elastically compressed returning to their original state. Utilizing this property, if a magnet with the sheet material thermocompression bonded to the magnet body is placed in the slot of the rotor core to expand the sheet material, the magnet can be fixed to the rotor core.

[0013] In the above configuration, in the intermediate body manufacturing step, the sheet material is thermocompression bonded to a plurality of magnet bodies. As a result, in the cutting step, a plurality of magnets in a state where the sheet material is thermocompression bonded to the magnet bodies can be produced. If these plurality of magnets are simply placed in the slots of the rotor core and heated, the magnets can be fixed to the rotor core. Thus, according to the above configuration, the rotor can be manufactured very efficiently.

[0014] A method for manufacturing a rotor for solving the above problems includes an intermediate body manufacturing step of manufacturing an intermediate body in which the sheet material is thermocompression bonded to a plurality of magnet bodies while heating the sheet material to a temperature equal to or higher than the glass transition temperature of the thermoplastic resin fibers and applying pressure with a plurality of magnet bodies located on the same surface of the sheet material containing thermoplastic resin fibers and inorganic fibers so that the inorganic fibers are elastically compressed, an arrangement step of arranging the intermediate body between a first mold made of an elastic material having a smaller elastic modulus than the magnet body and a second mold facing the first mold such that the surface of the sheet material opposite to the side where the magnet body is located faces the first mold, and sandwiching the intermediate body between the first mold and the second mold. With the elastic deformation of the first type,A cutting step of cutting the sheet material between the magnet bodies arranged adjacent to each other to produce a magnet in which the magnet body is covered with the sheet material, and a fixing step of fixing the magnet to the rotor core by heating the magnet in a state where the magnet is arranged in a slot vacant in the rotor core to a temperature equal to or higher than the glass transition temperature to elastically restore the inorganic fiber.

[0015] When a sheet material containing thermoplastic resin fibers and inorganic fibers is thermocompression-bonded to a magnet body and then heated again, the thermoplastic resin fibers in the sheet material are softened again, and the sheet material expands due to the action of the inorganic fibers that were elastically compressed returning to their original state. In the above configuration, this characteristic is utilized, and the magnet is fixed to the rotor core by expanding the sheet material thermocompression-bonded to the magnet body in the slot of the rotor core. In fixing the magnet to the rotor core in this way, in the above configuration, an intermediate body in which the sheet material is thermocompression-bonded to a plurality of magnet bodies is prepared in advance. Then, this intermediate body is sandwiched between a first mold and a second mold, and the intermediate body is cut between adjacent magnet bodies. When the first mold is pressed against the intermediate body by sandwiching the intermediate body between the first mold and the second mold, the first mold elastically deforms so as to extend in the lateral direction and also elastically deforms so as to enter between adjacent magnet bodies. As a result, a force in a direction in which the adjacent magnet bodies move away from each other acts on the adjacent magnet bodies. Also, at the edges of each magnet body, the force from the elastically deformed first mold tends to concentrate and act. As a result of these, the sheet material is cut between adjacent magnet bodies. This cutting of the sheet material occurs at various locations of the adjacent magnet bodies during the cutting step. Therefore, the sheet material can be cut efficiently.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Mode for Carrying Out the Invention

[0017] Hereinafter, an embodiment of a method for manufacturing a magnet and a method for manufacturing a rotor will be described with reference to the drawings. <Overall Configuration of the Motor> First, the schematic configuration of the motor will be described.

[0018] As shown in FIG. 1, the motor 50 has a stator 70, a rotor 60, and a shaft 55. The stator 70 is generally cylindrical as a whole. The stator 70 has a stator core 72 and a coil 76. Further, the stator core 72 has a main body of the stator core (hereinafter referred to as the stator core main body) 72A and a plurality of teeth 72B. The stator core main body 72A is cylindrical. The plurality of teeth 72B protrude from the inner peripheral surface of the stator core main body 72A toward the central axis J of the stator core main body 72A. The plurality of teeth 72B are arranged at equal intervals in the circumferential direction. In FIG. 1, a two-dot chain line is attached to the boundary between the stator core main body 72A and the teeth 72B.

[0019] The coil 76 is wound around each tooth 72B. The coil 76 extends beyond both ends of the stator core body 72A in the direction along the central axis J of the stator core body 72A. That is, the coil 76 protrudes from the stator core 72 in the direction along the central axis J of the stator core body 72A. In this specification, those coaxial with the central axis J of the stator core body 72A are given the unified reference numeral J.

[0020] The rotor 60 is cylindrical. The rotor 60 is located inside the stator core body 72A. The central axis J of the rotor 60 coincides with the central axis J of the stator core body 72A. There is a gap between the outer peripheral surface of the rotor 60 and the protruding ends of the respective teeth 72B in the stator 70. In FIG. 1, the illustration of this gap is omitted. The details of the rotor 60 will be described later. The rotor 60 is rotatable relative to the stator 70.

[0021] The shaft 55 is cylindrical. The shaft 55 passes through the central hole in the rotor 60. The central axis J of the shaft 55 coincides with the central axis J of the rotor 60. The shaft 55 rotates integrally with the rotor 60.

[0022] <Configuration of Rotor> The rotor 60 will be described in detail. The rotor 60 has a rotor core 62 and a plurality of magnets 80. The rotor core 62 is cylindrical. Although illustration is omitted, the rotor core 62 is formed by laminating a plurality of electromagnetic steel sheets processed into an annular shape in the direction along their central axis J.

[0023] The rotor core 62 has a plurality of slots 64. The plurality of slots 64 are through holes that penetrate the rotor core 62 in the direction along its central axis J. As shown in FIG. 2, the plurality of slots 64 are located near the outer periphery of the rotor core 62. The plurality of slots 64 are arranged in the circumferential direction of the rotor core 62.

[0024] As shown in FIG. 2, the slot 64 is substantially rectangular in a plan view from a direction along the central axis J of the rotor core 62. A total of eight pairs of slots 64 are provided with each pair being adjacent in the circumferential direction. In a plan view from a direction along the central axis J of the rotor core 62, the two paired slots 64 are arranged in a V shape. Specifically, the closer the two paired slots 64 are to the inner peripheral side of the rotor core 62, the closer the distance between them becomes.

[0025] The plurality of magnets 80 are located within each slot 64. That is, there is one magnet 80 for each slot 64. Each magnet 80 has a main body of the magnet (hereinafter referred to as the magnet main body) 82 and two sheet materials 86.

[0026] The magnet main body 82 is composed of a permanent magnet. In the present embodiment, the magnet main body 82 is a neodymium magnet made of iron, neodymium, boron, etc. as raw materials. As shown in FIG. 3, the magnet main body 82 is in the shape of a rectangular plate. Specifically, the magnet main body 82 has two first surfaces 82A, two second surfaces 82B, and two third surfaces 82C. The first surface 82A is the surface with the largest area among the outer surfaces of the magnet main body 82. The first surface 82A is rectangular. The first surface 82A is not curved and is planar. The two first surfaces 82A are in a parallel positional relationship with each other. The second surface 82B connects the long sides of the two first surfaces 82A. That is, the second surface 82B is adjacent to the first surface 82A. The second surface 82B is not curved and is planar. The first surface 82A and the second surface 82B are substantially orthogonal. That is, the boundary 82S between the first surface 82A and the second surface 82B is angular. The third surface 82C connects the short sides of the two first surfaces 82A. That is, the third surface 82C is adjacent to the first surface 82A. The third surface 82C is not curved and is planar. The first surface 82A and the third surface 82C are substantially orthogonal. That is, the boundary 82T between the first surface 82A and the third surface 82C is angular.

[0027] The sheet material 86 is a non-woven fabric made of fibers of polyetherimide, which is a thermoplastic resin fiber, and glass fibers, which are inorganic fibers. The two sheet materials 86 cover the two first surfaces 82A of the magnet body 82, respectively. The two sheet materials 86 constitute an insulating layer. Note that in each figure of the drawings, the thickness of the sheet material 86 is exaggerated and shown large.

[0028] The shape and dimensions of the magnet 80 are generally the same as those of the slot 64. As shown in FIG. 2, in a plan view from the direction along the central axis J of the rotor core 62, the direction along the short side of the rectangular slot 64 is referred to as the width direction of the slot 64. As shown in FIG. 1, in a state where the magnet 80 is fixed to the slot 64, the two sheet materials 86 of the magnet 80 are in contact with the inner surfaces on both sides in the width direction of the slot 64. Also, with respect to the direction along the central axis J of the rotor core 62, the positions of both ends of the magnet 80 coincide with the positions of both ends of the slot 64. Note that as shown in FIG. 2, in a plan view from the direction along the central axis J of the rotor core 62, there is a gap between the magnet 80 and the inner surfaces on both longitudinal sides of the slot 64.

[0029] As shown in FIG. 2, a pair of magnets 80 arranged in a pair of slots 64 form each magnetic pole of the motor 50. That is, the radially outer surfaces of a pair of magnets 80 arranged in a pair of slots 64 are magnetized to the same polarity with respect to each other. And these pair of magnets 80 form magnetic poles of N pole or S pole. Also, the polarities are reversed between a pair of magnets 80 and a pair of magnets 80 located adjacent thereto. As a result, in the rotor 60, N poles and S poles are alternately arranged in the circumferential direction.

[0030] <Intermediate manufacturing apparatus> An intermediate manufacturing apparatus 200 used when manufacturing the above-described magnet 80 will be described. Note that in the following description, the up and down in the drawings are used as a reference, but the up and down in the drawings do not necessarily coincide with the actual up and down.

[0031] As shown in FIG. 6, the intermediate body manufacturing apparatus 200 is a press die apparatus. The intermediate body manufacturing apparatus 200 includes a first pressing die 201 and a second pressing die 202. The first pressing die 201 is generally rectangular parallelepiped-shaped. The first pressing die 201 is made of copper. The reason for adopting copper as the material of the first pressing die 201 is due to its high thermal conductivity. The shape and material of the second pressing die 202 are the same as those of the first pressing die 201. The second pressing die 202 is located above the first pressing die 201. The upper surface of the first pressing die 201 and the lower surface of the second pressing die 202 face each other. The second pressing die 202 is driven by a servo motor to approach and separate from the first pressing die 201.

[0032] The first pressing die 201 has a first recess 201A. The first recess 201A is recessed on the upper surface of the first pressing die 201. The shape of the first recess 201A when the first pressing die 201 is viewed from above is rectangular. The dimensions of the long side and the short side of the first recess 201A when the first pressing die 201 is viewed from above are larger than the dimensions of the long side and the short side of the sheet material 86 prepared in the preparation step S10 described later. The depth of the recess of the first recess 201A is smaller than half of the thickness of the magnet body 82. The second pressing die 202 has a second recess 202A similar to the first recess 201A of the first pressing die 201. The second recess 202A is recessed on the lower surface of the second pressing die 202.

[0033] The intermediate manufacturing apparatus 200 includes two heaters H, two cooling water passages W, two temperature sensors T, and a load sensor 204. One heater H is located inside the first pressurizing type 201. The other heater H is located inside the second pressurizing type 202. Each heater H can adjust the temperature of each of the first pressurizing type 201 and the second pressurizing type 202. One cooling water passage W is a space partitioned inside the first pressurizing type 201. The other cooling water passage W is a space partitioned inside the second pressurizing type 202. Although not shown, outside the first pressurizing type 201 and the second pressurizing type 202, there is a switching mechanism that allows or prohibits the flow of cooling water through the two cooling water passages W. One temperature sensor T detects the temperature of the first recess 201A of the first pressurizing type 201. The other temperature sensor T detects the temperature of the second recess 202A of the second pressurizing type 202. Each temperature sensor T is composed of, for example, a thermocouple. The load sensor 204 detects the force applied to an object sandwiched between the first pressurizing type 201 and the second pressurizing type 202 when the second pressurizing type 202 approaches the first pressurizing type 201. The load sensor 204 is composed of, for example, a load cell. In FIG. 6, for the sake of convenience, the load sensor 204 is shown on the side surface of the first pressurizing type 201.

[0034] <Cutting device> The cutting device 300 used when manufacturing the above magnet 80 will be described. As shown in FIG. 7, the cutting device 300 includes a first base member 301 and a second base member 302. The first base member 301 is generally rectangular parallelepiped-shaped. The first base member 301 is made of metal. The shape and material of the second base member 302 are the same as those of the first base member 301. The second base member 302 is located above the first base member 301. The second base member 302 approaches or separates from the first base member 301 by being driven by a servo motor.

[0035] The cutting device 300 has a first type 303 and a second type 304. The first type 303 is generally rectangular parallelepiped-shaped. The first type 303 is made of an elastic material. Specifically, the material of the first type 303 is a thermosetting elastomer, that is, rubber. The elastic modulus of the first type 303 is smaller than that of the magnet body 82. The Shore hardness of the first type 303 is about 70 - 90 HS. The Shore hardness is an index indicating the hardness of an object. The larger the Shore hardness, the harder the object. The shape, material, elastic modulus, and Shore hardness of the second type 304 are the same as those of the first type 303.

[0036] The first type 303 and the second type 304 are located between the first base member 301 and the second base member 302. Specifically, the first type 303 is located on the upper surface of the first base member 301. The first type 303 is fixed to the upper surface of the first base member 301. The second type 304 is located on the lower surface of the second base member 302. The second type 304 is fixed to the lower surface of the second base member 302. The lower surface of the second type 304 faces the upper surface of the first type 303. Both the lower surface of the second type 304 and the upper surface of the first type 303 are not curved and are planar. The second type 304 operates integrally with the second base member 302. That is, when the second base member 302 approaches or separates from the first base member 301, the second type 304 approaches or separates from the first type 303.

[0037] <Manufacturing Method of Magnet and Rotor> The manufacturing methods of the magnet 80 and the rotor 60 will be described. As shown in FIG. 4, the manufacturing method of the rotor 60 has each process of a preparation process S10, an intermediate body manufacturing process S20, an arrangement process S30, a cutting process S40, an insertion process S50, and a fixing process S60. Among these six processes, the magnet 80 is manufactured by the processes from the preparation process S10 to the cutting process S40. That is, the manufacturing method of the magnet 80 has each process from the preparation process S10 to the cutting process S40.

[0038] When manufacturing the rotor 60, first, the preparation process S10 is performed. In the preparation process S10, the rotor core 62, the magnet body 82, and the sheet material 86 are prepared. For the rotor core 62 and the magnet body 82, those with the shapes already described are prepared. Note that, for the magnet body 82, 16 pieces are prepared per rotor core 62 in accordance with the number of slots 64 in the rotor core 62. For the sheet material 86, 2 pieces are prepared per rotor core 62. The sheet material 86 is rectangular. As shown in FIG. 5, the dimension of the short side Y1 of the sheet material 86 is longer than the dimension of the long side of the first surface 82A of the magnet body 82. The dimension of the long side Y2 of the sheet material 86 is longer than 32 times the dimension of the short side of the first surface 82A of the magnet body 82. In the following description, regarding the two sheet materials 86, when they are individually described, they are referred to as the first sheet material 86A and the second sheet material 86B, and when they are collectively described, they are referred to as the sheet material 86.

[0039] <Intermediate body manufacturing process> As shown in FIG. 4, after the preparation process S10, the intermediate body manufacturing process S20 is performed. The intermediate body manufacturing process S20 is a process of manufacturing the intermediate body 88 using the intermediate body manufacturing apparatus 200. Note that, at the start of the intermediate body manufacturing process S20, the second pressurizing mold 202 of the intermediate body manufacturing apparatus 200 is stopped at the initial position. The initial position is a position where the second pressurizing mold 202 is considerably separated from the first pressurizing mold 201.

[0040] As shown by the arrow U1 in FIG. 5, in the intermediate body manufacturing step S20, first, for example, the first sheet material 86A is placed into the first recess 201A of the first press mold 201 in the intermediate body manufacturing apparatus 200 by a robot hand. Then, as shown by the arrow U2 in FIG. 5, 16 magnet bodies 82 are arranged on the first sheet material 86A. When arranging each magnet body 82 on the first sheet material 86A, the first surface 82A of each magnet body 82 faces the first sheet material 86A. Also, the long side of the first surface 82A of each magnet body 82 is made parallel to the short side Y1 of the first sheet material 86A. In this case, the second surfaces 82B of adjacent magnet bodies 82 face each other. In such a state, the 16 magnet bodies 82 are arranged in a row at intervals from each other. The gap between adjacent magnet bodies 82 is made shorter than the dimension of the short side of the first surface 82A of the magnet body 82. After that, as shown by the arrow U3 in FIG. 5, the second sheet material 86B is placed on the 16 magnet bodies 82. At this time, the four sides of the second sheet material 86B and the four sides of the first sheet material 86A are aligned. In this way, the upper and lower first surfaces 82A of each magnet body 82 are covered by the two sheet materials 86. Note that when the second sheet material 86B is viewed from above in a plan view, the second sheet material 86B protrudes from the 16 magnet bodies 82. That is, the first sheet material 86A also protrudes from the 16 magnet bodies 82.

[0041] After that, the intermediate manufacturing apparatus 200 is driven. Then, as indicated by the arrow A in FIG. 6, the second pressing mold 202 approaches the first pressing mold 201. And the bottom surface of the depression in the first recess 201A of the first pressing mold 201 and the bottom surface of the depression in the second recess 202A of the second pressing mold 202 sandwich the two sheet materials 86 and the 16 magnet bodies 82. At this time, the first sheet material 86A is sandwiched between the bottom surface of the first recess 201A and the first surface 82A of each magnet body 82. Similarly, the second sheet material 86B is also sandwiched between the bottom surface of the second recess 202A and the first surface 82A of each magnet body 82. The second pressing mold 202 stops operating at a position where the force applied to the two sheet materials 86 becomes the specified load N. Note that the force applied to the two sheet materials 86 can be grasped from the detected value of the load sensor 204. The above-mentioned specified load N is set to be greater than or equal to the minimum load required to elastically compress the glass fibers of the sheet material 86 and less than the minimum load at which the glass fibers break, and is determined in advance by experiments, for example. In FIG. 6, dots are added to the first sheet material 86A and the second sheet material 86B for easy understanding of the two sheet materials 86.

[0042] After that, the first pressing mold 201 and the second pressing mold 202 are heated by the heater H. Then, the temperature of the first recess 201A of the first pressing mold 201 is set to the first specified temperature Z1. Also, the temperature of the second recess 202A of the second pressing mold 202 is set to the first specified temperature Z1. The temperature of each recess 201A, 202A can be grasped from the detected value of the temperature sensor T. The above-mentioned first specified temperature Z1 is set in advance to be equal to or higher than the glass transition temperature of the polyetherimide constituting the sheet material 86 and lower than the temperature at which the polyetherimide vaporizes. In the present embodiment, the first specified temperature Z1 is set to be slightly higher than the glass transition temperature of the polyetherimide.

[0043] The state of pressing while heating the two sheet materials 86 as described above is maintained for the first specified period L1. The first specified period L1 is set in advance by experiments, for example, as the length of time required for the polyetherimide to soften to such an extent that the glass fibers of the sheet material 86 are elastically compressed in a state where the sheet material 86 is at the first specified temperature Z1.

[0044] Thereafter, while maintaining the pressure on the two sheet materials 86, the temperatures of the first pressing mold 201 and the second pressing mold 202 are lowered. For example, the temperature of heating by the heater H is lowered, or cooling water is caused to flow through the cooling water passage W. Then, the temperature of the first recess 201A of the first pressing mold 201 is set to the second specified temperature Z2. Also, the temperature of the second recess 202A of the second pressing mold 202 is set to the second specified temperature Z2. The second specified temperature Z2 is predetermined as a temperature lower than the glass transition temperature of the polyetherimide. In the present embodiment, the second specified temperature Z2 is set as a temperature slightly lower than the glass transition temperature of the polyetherimide.

[0045] Thereafter, while maintaining the pressure on the two sheet materials 86, a state in which the first recess 201A of the first pressing mold 201 and the second recess 202A of the second pressing mold 202 are lowered to the second specified temperature Z2 is maintained for the second specified period L2. The second specified period L2 is, for example, predetermined by an experiment as the length of time required for the polyetherimide of the sheet material 86 to solidify in a state where the sheet material 86 is at the second specified temperature Z2.

[0046] After the elapse of the second specified period L2, the second pressing mold 202 is returned to the initial position. Then, in the first recess 201A of the first pressing mold 201, an intermediate body 88 is formed in which the two sheet materials 86 are thermocompression-bonded to the upper and lower two first surfaces 82A of each magnet body 82, respectively. At this point, the inorganic fibers of the two sheet materials 86 are in an elastically compressed state. The above series of steps is the intermediate body production step S20. As described above, the intermediate body 88 is obtained by covering the two first surfaces 82A of each magnet body 82 with the sheet material 86, respectively. In other words, in the intermediate body 88, one first surface 82A of each magnet body 82 is located on the same surface of the first sheet material 86A, and the other first surface 82A of each magnet body 82 is located on the same surface of the second sheet material 86B.

[0047] <Arrangement Step> As shown in FIG. 4, after the intermediate body manufacturing step S20, an arrangement step S30 is performed. The arrangement step S30 is a step of arranging the intermediate body 88 in the cutting device 300. At the start of the arrangement step S30, the second base member 302 and the second mold 304 of the cutting device 300 are stopped at the initial positions. The initial positions are positions where the second mold 304 is considerably separated from the first mold 303. In this state, for example, by a robot hand, the intermediate body 88 is arranged on the upper surface of the first mold 303 as shown in FIG. 7. At this time, the first sheet material 86A is made to face the upper surface of the first mold 303. That is, the surface of the first sheet material 86A on the side opposite to the side where the first surface 82A of the magnet body 82 is located faces the upper surface of the first mold 303. Also, the surface of the second sheet material 86B on the side opposite to the side where the first surface 82A of the magnet body 82 is located faces the lower surface of the second mold 304. Similar to FIG. 6, dots are attached to the first sheet material 86A and the second sheet material 86B in FIG. 7.

[0048] <Cutting Step> As shown in FIG. 4, after the placement step S30, a cutting step S40 is performed. The cutting step S40 is a step of cutting the two sheet materials 86 in the intermediate body 88. In the cutting step S40, the cutting device 300 is driven. Then, as shown by the arrow B in FIG. 8, the second mold 304 approaches the first mold 303 together with the second base member 302. Then, the first mold 303 and the second mold 304 sandwich the intermediate body 88. When the second mold 304 operates to a predetermined approaching position Q, the second base member 302 and the second mold 304 stop operating. And it waits for the waiting period M only in this state. The waiting period M is, for example, 5 seconds. During this waiting period M, the two sheet materials 86 are cut for each magnet body 82. That is, the two sheet materials 86 are cut between adjacent magnet bodies 82, or are cut along the long side or the short side of the first surface 82A of each magnet body 82. The mechanism by which the sheet material 86 is cut will be described in the column of the action described later. The above-mentioned approaching position Q is determined in advance by an experiment, for example, as a position where the force required to cut the sheet material 86 is applied to the intermediate body 88. Also, the waiting period M is determined in advance by an experiment, for example, as the length of time required until the cutting of the sheet material 86 is completed in the state where the second mold 304 has stopped at the approaching position Q. Similar to FIG. 7, in FIG. 8, dots are attached to the first sheet material 86A and the second sheet material 86B.

[0049] After this, the second mold 304 is returned to the initial position together with the second base member 302. Then, on the upper surface of the first mold 303, 16 magnets 80 and scraps of the sheet material 86 are formed. The magnet 80 is obtained by covering the two first surfaces 82A of the magnet body 82 with the sheet material 86, respectively.

[0050] <Insertion Step> As shown in FIG. 4, after the cutting step S40, an insertion step S50 is performed. The insertion step S50 is a step of inserting the magnets 80 into the respective slots 64 of the rotor core 62. As shown in FIG. 9, in the insertion step S50, for example, a disk-shaped support plate 400 is arranged substantially horizontally. Then, the rotor core 62 is arranged on the support plate 400. At this time, one of the two openings in each slot 64 faces the support plate 400, and the other faces upward. Then, as shown by the arrow C in FIG. 9, the magnets 80 are inserted into the respective slots 64 of the rotor core 62 on the support plate 400, for example, by a robot hand.

[0051] Note that at the stage where the magnets 80 are manufactured by the cutting step S40, the sheet material 86 of the magnets 80 is in a state compressed by thermocompression bonding. Therefore, the thickness of the magnets 80 including the sheet material 86 is smaller than the dimension in the width direction of the slots 64 in the rotor core 62. Therefore, when the magnets 80 are inserted into the slots 64 in the insertion step S50, the magnets 80 quickly move into the slots 64.

[0052] <Fixing Step> As shown in FIG. 4, after the insertion step S50, a fixing step S60 is performed. The fixing step S60 is a step of fixing the magnets 80 to the rotor core 62. As shown in FIG. 10, in the fixing step S60, a furnace 500 capable of temperature adjustment is used. Specifically, in the fixing step S60, the rotor core 62 with the magnets 80 inserted into the respective slots 64 is arranged in the furnace 500 together with the support plate 400. Then, the rotor core 62 is heated in the furnace 500. At this time, the temperature in the furnace 500 is adjusted to a third specified temperature Z3. The third specified temperature Z3 is set in advance to be a temperature equal to or higher than the glass transition temperature of the polyetherimide constituting the sheet material 86 and lower than the temperature at which the polyetherimide vaporizes. In the present embodiment, the third specified temperature Z3 is set to be the same temperature as the first specified temperature Z1.

[0053] The heating of the rotor core 62 in the furnace 500 continues for the third specified period L3. The third specified period L3 is determined in advance by experiments or the like as the length of time required for the polyetherimide to soften to such an extent that the glass fibers of the sheet material 86 can elastically recover when the sheet material 86 is at the third specified temperature Z3. After the heating of the rotor core 62 continues for the third specified period L3, the rotor core 62 is taken out of the furnace 500. After that, the rotor core 62 is returned to room temperature. Thus, the rotor 60 is completed.

[0054] <Operation of the Embodiment> (A) Regarding the mechanism for fixing the magnet to the slot As shown in FIG. 6, in the intermediate body manufacturing step S20, the first recess 201A of the first pressurizing mold 201 and the second recess 202A of the second pressurizing mold 202 are heated to a temperature higher than the glass transition temperature of the polyetherimide. Along with this, the polyetherimide of the sheet material 86 located on the first surface 82A of each magnet body 82 softens. Then, in the intermediate body manufacturing step S20, the sheet material 86 is pressurized. As a result, the glass fibers of the sheet material 86 are bent and elastically compressed. Further, in the intermediate body manufacturing step S20, while maintaining the state where the sheet material 86 is pressurized, the first recess 201A of the first pressurizing mold 201 and the second recess 202A of the second pressurizing mold 202 are cooled to a temperature lower than the glass transition temperature of the polyetherimide. As a result, the sheet material 86 is bonded to the first surface 82A of each magnet body 82 while the glass fibers are in an elastically compressed state.

[0055] Due to the above reasons, at each magnet 80 at the time of being produced in the cutting step S40, the sheet material 86 is in a state of elastic compression. In the fixing step S60, such a sheet material 86 is reheated to a temperature higher than the glass transition temperature of the polyetherimide. Along with this, the polyetherimide of the sheet material 86 is softened again. Then, the glass fibers that were elastically compressed elastically return. Along with this, as shown by the arrow D in FIG. 10, the sheet material 86 expands from the position where the glass fibers shown by the two-dot chain line in FIG. 10 were elastically compressed. When the sheet material 86 expands and reaches the inner surface of the slot 64, the magnet 80 is fixed in the slot 64 by the frictional action due to the contact between the sheet material 86 and the inner surface of the slot 64.

[0056] (b) Mechanism for cutting the sheet material As shown in FIG. 8, in the cutting step S40, the intermediate body 88 is sandwiched between the first mold 303 and the second mold 304. That is, the first mold 303 and the second mold 304 are pressed against the intermediate body 88. Along with the elastic deformation of the first mold 303 and the second mold 304 at this time, the sheet material 86 is cut. Hereinafter, taking the first mold 303 as an example, the relationship between the elastic deformation of the first mold 303 and the cutting of the sheet material 86 will be described.

[0057] As shown in Fig. 8, when the first mold 303 is pressed against the first sheet material 86A, the first mold 303 is crushed from above and below by the first base member 301 and the first surface 82A of the magnet body 82. As a result, as shown by the arrow B1 in Fig. 8, the portion of the first mold 303 directly below the first surface 82A of the magnet body 82 elastically deforms so as to extend in the lateral direction. While elastically deforming in the lateral direction in this way, the first mold 303 further elastically deforms so as to enter between adjacent magnet bodies 82 as shown by the arrow B2 in Fig. 8. The first mold 303 that has entered between adjacent magnet bodies 82 while elastically deforming in the lateral direction attempts to expand the region between the adjacent magnet bodies 82 in the lateral direction. That is, a force in a direction in which the adjacent magnet bodies 82 move away from each other acts on the adjacent magnet bodies 82. As a result, the distance between the adjacent magnet bodies 82 increases. As a result, a large tension is applied to the portion of the first sheet material 86A between the adjacent magnet bodies 82, and the first sheet material 86A breaks.

[0058] Also, the sheet material 86 may break due to a balance with the shape of the magnet body 82. The boundary 82S between the first surface 82A and the second surface 82B of the magnet body 82 is angular. The boundary 82T between the first surface 82A and the third surface 82C of the magnet body 82 is also angular. Therefore, when the first mold 303 is pressed against the intermediate body 88, a force is likely to be applied from the first mold 303 to these boundaries 82S, 82T of the magnet body 82. As a result, the first sheet material 86A facing the first mold 303 breaks at the portions in contact with the boundaries 82S, 82T.

[0059] In the above, the first mold 303 and the first sheet material 86A have been described as examples, but the same can be said for the second mold 304 and the second sheet material 86B. In addition, at various locations of the intermediate body 88, there are places where the sheet material 86 is cut only due to the increase in the distance between adjacent magnet bodies 82, and there are also places where the sheet material 86 is cut only due to contact with the corners of the magnet bodies 82. Further, there are places where the sheet material 86 is cut due to the above two mechanisms overlapping. That is, the sheet material 86 is cut at the corners of the magnet bodies 82 in a state where a large tension is applied to the sheet material 86 due to the increase in the distance between adjacent magnet bodies 82.

[0060] <Effects of the Embodiment> (1) As described in the above operation, when the first mold 303 and the second mold 304 are pressed against the intermediate body 88 in the cutting step S40, the first mold 303 and the second mold 304 are elastically deformed so as to extend in the lateral direction and are elastically deformed so as to enter between adjacent magnet bodies 82. As a result, a force in a direction in which the adjacent magnet bodies 82 move away from each other acts on the adjacent magnet bodies 82. As a result, the sheet material 86 is cut between the adjacent magnet bodies 82. Such cutting of the sheet material 86 occurs at various locations of the adjacent magnet bodies 82. Therefore, the sheet material 86 can be efficiently cut.

[0061] (2) As described in the above operation, when the first mold 303 and the second mold 304 are pressed against the intermediate body 88, forces are likely to be applied from the first mold 303 and the second mold 304 to the boundary 82S between the first surface 82A and the second surface 82B and the boundary 82T between the first surface 82A and the third surface 82C of the magnet body 82. Therefore, the sheet material 86 can be cut at these boundaries 82S, 82T. Further, when the sheet material 86 is cut at the boundary between the surfaces of the magnet body 82 in this way, the sheet material 86 can be cut along the outer edge of the magnet body 82. Therefore, a magnet 80 with a small amount of excess portion protruding from the magnet body 82 can be produced.

[0062] (3) As described in the above operation, when the sheet material 86 containing the thermoplastic resin fiber and the inorganic fiber is thermocompression-bonded to the magnet body 82 and then heated again, the thermoplastic resin fiber in the sheet material 86 is softened again, and the sheet material 86 expands due to the action of the inorganic fiber that has returned to its original state after being elastically compressed. In the fixing step S60, by utilizing this property and expanding the sheet material 86 thermocompression-bonded to the magnet body 82 within the slot 64 of the rotor core 62, the magnet 80 is fixed to the rotor core 62. In order to fix the magnet 80 to the rotor core 62 in this way, in this embodiment, in the intermediate body manufacturing step S20, the sheet material 86 is thermocompression-bonded to 16 magnet bodies 82. As a result, in the cutting step S40, 16 magnets 80 in a state where the sheet material 86 is thermocompression-bonded to the magnet body 82 can be manufactured. That is, at the end of the cutting step S40, the sheet material 86 is already thermocompression-bonded to the magnet body 82. Therefore, in the fixing step S60, if these 16 magnets 80 are only heated within the slot 64 of the rotor core 62, the magnet 80 can be fixed to the rotor core 62. Therefore, by using the manufacturing method of the rotor 60 of this embodiment, the rotor 60 can be manufactured very efficiently.

[0063] Note that this embodiment can be implemented with the following modifications. This embodiment and the following modification examples can be implemented in combination with each other within a technically non-conflicting range. · The configuration of the cutting device 300 used in the cutting step S40 is not limited to the example of the above embodiment. The cutting device 300 may have a configuration capable of cutting the sheet material 86 when sandwiching the intermediate body 88 between the first type 303 and the second type 304. For example, like the cutting device 350 shown in FIG. 11, the upper surface of the first type 353 may have a planar flat surface 353P and a protruding surface 353B protruding from the flat surface 353P. Specifically, a plurality of convex portions 353A protrude from the flat surface 353P of the first type 353. The surface of the convex portion 353A is the protruding surface 353B. The plurality of convex portions 353A are arranged in a row at equal intervals. Specifically, the plurality of convex portions 353A are provided for each dimension of the short side of the first surface 82A of the magnet body 82. The protruding end of each convex portion 353A is planar. That is, a part of the protruding surface 353B is planar. Similarly, a plurality of convex portions 354A protrude from the flat surface 354P of the second type 354. The surface of the convex portion 354A is the protruding surface 354B. Each convex portion 354A of the second type 354 exists at a position facing each convex portion 353A of the first type 353.

[0064] When using the cutting device 350 as described above, in the intermediate body manufacturing step S20, the intermediate body 88 is manufactured with little gap between the magnet bodies 82. Then, in the arrangement step S30, the boundary 82S between the first surface 82A facing downward and the second surface 82B of the magnet body 82 faces the protruding surface 353B of the first type 353 with the first sheet material 86A sandwiched therebetween. When the intermediate body 88 is arranged in this way, the boundary 82S between the first surface 82A facing upward and the second surface 82B of the magnet body 82 will face the protruding surface 354B of the second type 354. The cutting step S40 is performed under such an arrangement.

[0065] When the convex portion 353A is provided on the upper surface of the first mold 353 as described above, when the first mold 353 is pressed against the intermediate body 88, in the first mold 353, force easily acts on the first sheet material 86A from the protruding surface 353B of the first mold 353. Specifically, a very strong force is applied to the portion of the first sheet material 86A sandwiched between the protruding surface 353B of the first mold 353 and the boundary 82S of the magnet body 82. Therefore, the first sheet material 86A can be more reliably cut at this portion. The same applies to the second sheet material 86B. In FIG. 11, the illustration of the first base member 301 and the second base member 302 is omitted. Also, in FIG. 11, as in FIG. 7, dots are added to the first sheet material 86A and the second sheet material 86B.

[0066] · As in the cutting device 370 shown in FIG. 12, a plurality of convex portions may be irregularly provided on the upper surface of the first mold 373. That is, on the upper surface of the first mold 373, continuous unevenness exists irregularly. For example, when the upper surface of the first mold 303 is planar as in the above embodiment, the force applied from the upper surface of the first mold 303 to the intermediate body 88 is substantially uniform at each location on the upper surface of the first mold 303. On the other hand, when a plurality of convex portions are irregularly provided on the upper surface of the first mold 373, the force applied from the upper surface of the first mold 373 to the intermediate body 88 is different at each location on the upper surface of the first mold 373. And in some places, a locally strong force is applied to the intermediate body 88. Due to the existence of a plurality of such places where a locally strong force is applied, for example, the first mold 373 may be elastically deformed irregularly between the first base member 301 and each magnet body 82 and act to move adjacent magnet bodies 82 away from each other. As a result, the sheet material 86 can be cut. Also, if a locally strong force is applied to the boundary 82S between the first surface 82A and the second surface 82B of the magnet body 82, the sheet material 86 can be cut at the boundary. Similar to the first mold 373, unevenness may be irregularly provided on the lower surface of the second mold 374. In FIG. 12, the illustration of the first base member 301 and the second base member 302 is omitted. Also, in FIG. 12, as in FIG. 7, dots are added to the first sheet material 86A and the second sheet material 86B.

[0067] · The Shore hardness of the first type 303 is not limited to the examples of the above embodiments. If the Shore hardness of the first type 303 is high, the sheet material 86 can be cut even with a small force pressing the first type 303 against the intermediate body 88. And if the force pressing the first type 303 against the intermediate body 88 is small, it is difficult for the first type 303 to be burdened, which is advantageous from the viewpoint of the durability of the first type 303. Considering such durability of the first type 303, an appropriate Shore hardness may be set, for example, in consideration of cost. The same applies to the Shore hardness of the second type 304. The Shore hardness may be different between the first type 303 and the second type 304.

[0068] · The elastic moduli of the first type 303 and the second type 304 may be different from each other. The elastic modulus of the first type 303 may be smaller than that of the magnet body 82. The same applies to the second type 304.

[0069] · The material of the first type 303 is not limited to the examples of the above embodiments. The first type 303 may be made of an elastic material. The material of the first type 303 may be, for example, a thermoplastic elastomer. The same applies to the second type 304. The materials of the first type 303 and the second type 304 may be different from each other.

[0070] · As in the modification example described later, when only one sheet material 86 constituting the intermediate body 88 is used, the first type 303 may be made of an elastic material, and the second type 304 does not have to be made of an elastic material. In this case, in the arranging step S30, the sheet material 86 may be arranged to face the first type 303.

[0071] · Regarding the arrangement of the first type 303 and the second type 304, they may be arranged with their vertical positions swapped from the aspect of the above embodiments. That is, the first type 303 may be located above the second type 304.

[0072] · The first type 303 and the second type 304 may be arranged side by side in the direction of gravity or may be arranged side by side along the horizontal plane. For example, when the first type 303 and the second type 304 are arranged side by side along the horizontal plane, in the arranging step S30, for example, the intermediate body 88 is suspended between the first type 303 and the second type 304. Then, in the cutting step S40, the intermediate body 88 is sandwiched between the first type 303 and the second type 304 from both sides in the direction along the horizontal plane. By adopting such a mode, the sheet material 86 may be cut.

[0073] · The mechanism for driving the cutting device 300 may be changed from the example of the above embodiment. For example, the cutting device 300 may be driven by hydraulic pressure. · The waiting period M of the cutting step S40 is not limited to the example of the above embodiment. The waiting period M may be the length of time required for the cutting of the sheet material 86 to be completed.

[0074] · The method of manufacturing the intermediate 88 in the intermediate manufacturing step S20 is not limited to the examples of the above embodiments. For example, as shown in FIG. 13, the intermediate 88 may be manufactured using a pressing jig 600. The pressing jig 600 has, for example, a first plate 601 and a second plate 602 made of copper. When manufacturing the intermediate 88 using the pressing jig 600, first, a first sheet material 86A is disposed on the first plate 601. Then, a plurality of magnet bodies 82 are disposed on the first sheet material 86A. After that, a second sheet material 86B is disposed on the plurality of magnet bodies 82. And then, the second plate 602 is disposed thereon. In this way, the one obtained by covering the plurality of magnet bodies 82 with two sheet materials 86 is sandwiched between the first plate 601 and the second plate 602. And the first plate 601 and the second plate 602 are fixed with bolts 603 in a state where a specified load N is applied to the two sheet materials 86. In this state, each magnet body 82 and the two sheet materials 86 are disposed in the furnace 650 together with the pressing jig 600. The furnace 650 is capable of temperature adjustment. After that, the temperature in the furnace 650 is set to a first specified temperature Z1 and maintained for a first specified period L1. Then, the temperature in the furnace 650 is set to a second specified temperature Z2 and maintained for a second specified period L2. After that, the pressing jig 600 is taken out from the furnace 650. And when the second plate 602 is removed together with the bolts 603, the intermediate 88 is formed. The intermediate 88 may be manufactured in this way. In FIG. 13, as in FIG. 6, dots are attached to the first sheet material 86A and the second sheet material 86B.

[0075] · The configuration of the intermediate 88 is not limited to the examples of the above embodiments. For example, the number of magnet bodies 82 included in the intermediate 88 may be changed from the number in the above embodiments. The number of magnet bodies 82 included in the intermediate 88 may be more than the number of slots 64 of one rotor core 62. The number of magnet bodies 82 included in the intermediate 88 may be two or more.

[0076] · The arrangement of the magnet bodies 82 in the intermediate 88 is not limited to the examples of the above embodiments. For example, the plurality of magnet bodies 82 may be arranged in a plurality of rows. ·In the intermediate body 88, there may not be any gap between adjacent magnet bodies 82. Even when the first type 303 and the second type 304 are pressed against such an intermediate body 88, the sheet material 86 will be cut according to the elastic deformation of the first type 303 and the second type 304. That is, when the first type 303 is pressed against the intermediate body 88, the first type 303 is crushed between the first base member 301 and each magnet body 82 and elastically deforms so as to extend laterally. Along with such elastic deformation, the first type 303 moves the adjacent magnet bodies 82 apart. As a result, the sheet material 86 is cut between the adjacent magnet bodies 82. The same applies to the second type 304.

[0077] ·The shape and dimensions of the sheet material 86 are not limited to the examples of the above embodiment. The shape and dimensions of the sheet material 86 may be appropriately adjusted so as to be able to cover the plurality of magnet bodies 82 constituting the intermediate body 88.

[0078] ·The intermediate body 88 does not necessarily have to be one in which the sheet material 86 is thermocompression-bonded to the plurality of magnet bodies 82. For example, the intermediate body 88 may be one in which the sheet material 86 is attached to the plurality of magnet bodies 82 with an adhesive or double-sided adhesive tape, for example. In this case, since it is sufficient if the sheet material 86 can be temporarily fixed to the magnet body 82, the adhesive force of the adhesive or double-sided adhesive tape does not have to be very high. When such an intermediate body 88 is adopted, after the cutting step S40, the sheet material 86 may be thermocompression-bonded to the magnet body 82. The intermediate body 88 may have a configuration in which a plurality of magnet bodies 82 are located on the same surface of the sheet material 86.

[0079] ·The intermediate body 88 may be formed with only one sheet material 86. That is, the intermediate body 88 may have a configuration in which the sheet material 86 covers only one of the two first surfaces 82A of each magnet body 82.

[0080] ·The configuration of the intermediate manufacturing apparatus 200 is not limited to the examples of the above-described embodiments. The intermediate manufacturing apparatus 200 may have any configuration as long as it can pressurize while heating the sheet material 86. For example, the mechanism for driving the intermediate manufacturing apparatus 200 may be changed from the examples of the above-described embodiments. For example, the intermediate manufacturing apparatus 200 may be driven by hydraulic pressure.

[0081] ·The material of the first pressurizing mold 201 is not limited to the examples of the above-described embodiments. For example, the first pressurizing mold 201 may be made of iron. The same applies to the second pressurizing mold 202. The materials of the first pressurizing mold 201 and the second pressurizing mold 202 may be different from each other.

[0082] ·When the sheet material 86 constituting the intermediate 88 is made into one as in the above modification example, the heater H incorporated in either the first pressurizing mold 201 or the second pressurizing mold 202 is not necessarily required. In this case, the unnecessary heater H may be abolished. The same applies to the cooling water passage W. Also, with respect to the cooling water passage W, it may be abolished from both the first pressurizing mold 201 and the second pressurizing mold 202. Even in this case, the intermediate manufacturing apparatus 200 can be cooled by leaving a time after stopping the heater H.

[0083] ·As a mechanism for cooling the first pressurizing mold 201, a configuration other than the cooling water passage W may be used. The same applies to the mechanism for cooling the second pressurizing mold 202. ·The first specified temperature Z1 in the intermediate production step S20 may be considerably higher than the glass transition temperature of the thermoplastic resin fiber.

[0084] ·The second specified temperature Z2 in the intermediate production step S20 may be considerably lower than the glass transition temperature of the thermoplastic resin fiber. The second specified temperature Z2 may be, for example, room temperature. ·The third specified temperature Z3 in the fixing step S60 may be different from the first specified temperature Z1 in the intermediate production step S20.

[0085] ·The method of heating the sheet material 86 in the fixing process S60 is not limited to the examples of the above embodiments. For example, high-frequency induction heating may be used. That is, the rotor core 62 in a state where the magnet 80 is accommodated in the slot 64 is arranged inside the coil for induction heating. Then, by passing an electric current through the coil to generate a magnetic field, the sheet material 86 may be heated together with the rotor core 62.

[0086] ·The type of permanent magnet constituting the magnet body 82 is not limited to the examples of the above embodiments. The magnet body 82 may be any permanent magnet. Examples of the permanent magnet employed for the magnet body 82 include ferrite magnets, alnico magnets, samarium cobalt magnets, praseodymium magnets, samarium nitrogen iron magnets, platinum magnets, cerium cobalt magnets, and the like.

[0087] ·The shape of the magnet body 82 is not limited to the examples of the above embodiments. For example, the boundary portion between the first surface 82A and the second surface 82B may be chamfered. Even in this case, the first surface 82A and the second surface 82B are adjacent to each other via the chamfered surface. Also, the first surface 82A may be curved. Furthermore, the magnet body 82 may have any shape that can be accommodated in the slot 64 of the rotor core 62.

[0088] Note that by changing the shape of the magnet body 82 from the examples of the above embodiments, even when there are no angular portions in the magnet body 82, the first type 303 and the second type 304 can elastically deform and act to move the adjacent magnet bodies 82 apart, thereby cutting the sheet material 86.

[0089] ·The type of thermoplastic resin fiber constituting the sheet material 86 is not limited to the examples of the above embodiments. The thermoplastic resin fiber may be, for example, polyethersulfone or polysulfone. Here, the rotor 60 may become hot during the use of the motor 50. Also, depending on the usage environment of the motor 50, water or oil may splash onto the rotor 60, or an external force may act on the rotor 60. Considering such circumstances, it is preferable that the thermoplastic resin fiber has high heat resistance, water resistance, oil resistance, creep resistance, heat shock resistance, and insulation.

[0090] · When changing the type of thermoplastic resin fiber constituting the sheet material 86 as in the above modification example, the first specified temperature Z1 in the intermediate body production step S20 may be appropriately changed according to the glass transition temperature of the thermoplastic resin fiber to be employed. The first specified temperature Z1 may be determined as a temperature equal to or higher than the glass transition temperature of the thermoplastic resin fiber to be employed and lower than the temperature at which the thermoplastic resin fiber to be employed vaporizes. The same applies to the third specified temperature Z3 in the fixing step S60.

[0091] · Similar to the above modification example, the second specified temperature Z2 may be changed according to the glass transition temperature of the thermoplastic resin fiber to be employed. The second specified temperature Z2 may be determined as a temperature lower than the glass transition temperature of the thermoplastic resin fiber to be employed.

[0092] · The type of inorganic fiber constituting the sheet material 86 is not limited to the examples in the above embodiment. As the inorganic fiber, for example, rock wool, carbon fiber, alumina fiber, calcium silicate fiber, potassium titanate fiber, ceramic fiber, etc. may be employed.

[0093] · When changing the type of inorganic fiber constituting the sheet material 86 as in the above modification example, the specified load N in the intermediate body production step S20 may be appropriately changed according to the inorganic fiber to be employed. The specified load N may be determined as a magnitude equal to or greater than the minimum load required to elastically compress the inorganic fiber to be employed and less than the minimum load at which the inorganic fiber to be employed breaks.

[0094] · When changing the type of thermoplastic resin fibers or inorganic fibers that make up the sheet material 86, the first specified period L1 of the intermediate production step S20 may be appropriately changed according to the combination of the thermoplastic resin fibers and the inorganic fibers. The first specified period L1 may be defined as the length of time required for the inorganic plastic resin fibers to soften to such an extent that the inorganic fibers of the sheet material 86 are elastically compressed in a state where the sheet material 86 is at the first specified temperature Z1. Similarly, for the second specified period L2 of the intermediate production step S20 and the third specified period L3 of the fixing step S60, they may be appropriately changed according to the combination of the thermoplastic resin fibers and the inorganic fibers.

[0095] · The arrangement of the slots 64 in the rotor core 62 is not limited to the example of the above embodiment. The slots 64 may be arranged, for example, along the circumferential direction of the rotor core 62 instead of in the V-shaped arrangement as in the above embodiment. As long as the magnets 80 can be arranged such that the N poles and S poles alternate in the circumferential direction of the rotor core 62, the arrangement of the slots 64 does not matter.

[0096] · The number of slots 64 in the rotor core 62 is not limited to the example of the above embodiment. Similar to the above modification example, as long as the magnetic poles can be appropriately configured, the number of slots 64 does not matter. · If high efficiency is not emphasized in manufacturing the rotor 60, it is not essential to use the method of thermally expanding the sheet material 86 when fixing the magnet 80 to the rotor core 62. If the magnet 80 is fixed to the rotor core 62 by a method other than the method of thermally expanding the sheet material 86, the sheet material 86 may not contain thermoplastic resin fibers and inorganic fibers. Regardless of the configuration of the sheet material 86, it is effective to use the cutting device 300 when cutting the sheet material 86 of the intermediate 88 to produce a plurality of magnets 80.

[0097] · The cutting device 300 may be used to produce a plurality of magnets for applications other than manufacturing the magnets attached to the rotor 60.

Explanation of Reference Numerals

[0098] 60…Rotor 62… Rotor core 64… Slot 80… Magnet 82… Magnet body 82A… First surface 82B… Second surface 82S… Boundary 86… Sheet material 88… Intermediate body 303… First type 304… Second type 353… First type 354… Second type 353B… Protruding surface 353P… Flat surface 354B… Protruding surface 354P… Flat surface

Claims

1. An intermediate body manufacturing step of manufacturing an intermediate body in which a plurality of magnet bodies are located on the same surface of a sheet material, An arranging step of arranging the intermediate body between a first mold made of an elastic material having a smaller elastic modulus than the magnet body and a second mold facing the first mold, so that the surface of the sheet material opposite to the surface on which the magnet body is located faces the first mold, A cutting step of cutting the sheet material between the magnet bodies arranged adjacent to each other as the first mold elastically deforms by sandwiching the intermediate body with the first mold and the second mold. A method for manufacturing a magnet.

2. The magnet body has a planar first surface and a planar second surface adjacent to the first surface, In the intermediate body manufacturing step, a plurality of the magnet bodies are arranged on the same surface of the sheet material so that the first surface contacts the sheet material. The method for manufacturing a magnet according to Claim 1.

3. The surface of the first mold facing the sheet material has a planar flat surface and a protruding surface protruding from the flat surface, In the arranging step, the intermediate body is arranged so that the boundary between the first surface and the second surface of the magnet body faces the protruding surface with the sheet material interposed therebetween. The method for manufacturing a magnet according to Claim 2.

4. The sheet material contains thermoplastic resin fibers and inorganic fibers, In the intermediate body manufacturing step, the sheet material is thermocompression bonded to a plurality of the magnet bodies in a state where the inorganic fibers are elastically compressed by heating and pressing the sheet material at a temperature equal to or higher than the glass transition temperature of the thermoplastic resin fibers. The method for manufacturing a magnet according to any one of Claims 1 to 3.

5. An intermediate body manufacturing step of manufacturing an intermediate body in which the sheet material is thermocompression bonded to a plurality of magnet bodies in a state where the inorganic fibers are elastically compressed by heating and pressing the sheet material at a temperature equal to or higher than the glass transition temperature of the thermoplastic resin fibers while a plurality of magnet bodies are located on the same surface of the sheet material containing thermoplastic resin fibers and inorganic fibers, An arranging step of arranging the intermediate body between a first mold made of an elastic material having a smaller elastic modulus than the magnet body and a second mold facing the first mold, so that the surface of the sheet material opposite to the surface on which the magnet body is located faces the first mold, By sandwiching the intermediate body with the first type and the second type, along with the elastic deformation of the first type, a cutting step of cutting the sheet material between the magnet bodies arranged adjacent to each other to produce a magnet in which the magnet body is covered with the sheet material; A fixing step of fixing the magnet to the rotor core by heating the magnet at a temperature equal to or higher than the glass transition temperature with the magnet disposed in the slot provided in the rotor core to cause elastic recovery of the inorganic fiber. A method for manufacturing a rotor.

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