Rotor manufacturing method and rotor

Abstract

To suppress overflowing of adhesive from a magnet hole when a rotor is manufactured.SOLUTION: A rotor has a rotor core, a magnet, and adhesive. The rotor core has a magnet hole penetrating in a direction along a rotation axis. The magnet is located within the magnet hole. The adhesive is interposed between an internal surface of the magnet hole and an external surface of the magnet. The adhesive includes forming agent forming at a temperature equal to or more than a forming temperature Z2, and a thermoset resin hardening at a temperature equal to or more than hardening temperature Z1 lower than the forming temperature Z2. In a heating process in a manufacturing method of the rotor, a first end of a first direction side along the rotation axis and a second end of a second direction side opposite to the first direction among the adhesive are heated to the temperature equal to or more than the hardening temperature Z1 and less than the forming temperature Z2, and a center in the direction along the rotation axis among the adhesive is heated to the temperature equal to or more than the forming temperature Z2.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a rotor and a rotor. [Background technology]

[0002] Patent Document 1 describes a rotor of a motor generator. The rotor of Patent Document 1 includes a rotor core, a plurality of magnets, and a plurality of foamed resins. The rotor core includes a plurality of magnet holes. The magnet holes penetrate the rotor core in a direction along the rotation axis. The magnets are located within the magnet holes. The foamed resin is a thermosetting resin having a plurality of bubbles therein. The foamed resin is interposed between the inner wall surface of the magnet hole and the outer surface of the magnet.

[0003] Patent Document 1 also describes a method for manufacturing a rotor. In manufacturing the rotor of Patent Document 1, workers apply an adhesive containing a foaming agent and uncured thermosetting resin to the outer surface of a magnet, and then insert the magnet into the magnet hole of the rotor core. Then, the workers heat the adhesive to a temperature equal to or higher than the foaming temperature of the foaming agent and equal to or higher than the curing temperature of the thermosetting resin. Then, the foaming agent foams and the volume of the adhesive increases, so that the gap between the outer surface of the magnet and the inner wall surface of the magnet hole is filled with the adhesive. Then, the thermosetting resin hardens in this state, so that the magnet is held in the magnet hole. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2019 / 039442 Summary of the Invention [Problem to be solved by the invention]

[0005] In the rotor manufacturing method of Patent Document 1, when the adhesive is heated, the volume of the adhesive increases as it foams, which may cause the adhesive to overflow from the magnet holes. [Means for solving the problem]

[0006] A manufacturing method of a rotor for solving the above problem includes a rotor core having a magnet hole penetrating in a direction along the rotation axis, a magnet located in the magnet hole, and an adhesive interposed between the inner wall surface of the magnet hole and the outer surface of the magnet, wherein the adhesive contains a foaming agent that foams at a temperature equal to or higher than a foaming temperature and a thermosetting resin that hardens at a temperature equal to or higher than a hardening temperature that is lower than the foaming temperature, and includes a heating step of heating a first end of the adhesive on a first direction side along the rotation axis and a second end on a second direction side opposite the first direction to a temperature equal to or higher than the hardening temperature and lower than the foaming temperature to harden the thermosetting resin, and heating a center of the adhesive in the direction along the rotation axis to a temperature equal to or higher than the foaming temperature.

[0007] According to the above configuration, the first and second ends of the adhesive are heated to a temperature below the foaming temperature, so that the thermosetting resin hardens at the first and second ends of the adhesive without foaming the foaming agent. The hardened thermosetting resin thus functions as a plug, preventing the adhesive from overflowing from the magnet hole.

[0008] In the above configuration, in the heating step, the entire adhesive may be heated simultaneously so that the amount of heat applied per unit time to the center of the adhesive is greater than the amount of heat applied per unit time to the first end and the second end of the adhesive. According to the above configuration, the period for heating the adhesive can be shortened, for example, compared to a case in which the first end and the second end of the adhesive are heated and then the center of the adhesive is heated.

[0009] In the above configuration, in the heating step, the adhesive as a whole may be heated simultaneously while the first end and the second end are cooled so that the temperatures of the first end and the second end are equal to or higher than the curing temperature and lower than the foaming temperature.

[0010] According to the above configuration, even in a situation where the entire adhesive is heated to a temperature above the foaming temperature, for example, when only a heating device that heats the entire adhesive is used, the temperature of the first end and second end of the adhesive can be made lower than that of the center of the adhesive.

[0011] In the above configuration, the heating process may include a first heating process in which the first end and the second end of the adhesive are heated to a temperature equal to or higher than the curing temperature and lower than the foaming temperature to harden the thermosetting resin at the first end and the second end, and a second heating process in which, after the first heating process, the entire adhesive is heated to a temperature equal to or higher than the foaming temperature.

[0012] According to the above configuration, since the thermosetting resin at the first end and the second end of the adhesive is cured in the first heating step, even if the first end and the second end of the adhesive are subsequently heated to a temperature equal to or higher than the foaming temperature, the foaming agent at the first end and the second end of the adhesive is unlikely to foam. Therefore, in the second heating step, for example, a heating device that uniformly heats the entire adhesive can be used.

[0013] A rotor for solving the above problem comprises a rotor core having a magnet hole penetrating in a direction along the rotation axis, a magnet located within the magnet hole, and a foamed resin made of a thermosetting resin interposed between the inner wall surface of the magnet hole and the outer surface of the magnet, wherein the foamed resin has a first end on a first direction side along the rotation axis and a second end on a second direction side opposite to the first direction, and the foamed resin has a lower foaming rate at a first end on a first direction side along the rotation axis and a second end on a second direction side opposite to the first direction than a central foaming rate of the foamed resin in the direction along the rotation axis.

[0014] According to the above configuration, compared to a configuration in which the foaming rate of the first and second ends of the foamed resin is the same as the foaming rate of the center of the foamed resin, it is possible to prevent the thermosetting resin from overflowing from the magnet hole during manufacturing of the rotor. [Brief description of the drawings]

[0015] [Figure 1] FIG. 2 is a cross-sectional view of the motor generator. [Diagram 2] FIG. [Diagram 3] 4 is a flowchart showing a method for manufacturing a rotor. [Figure 4] 5A to 5C are explanatory diagrams showing a manufacturing method of the rotor. [Diagram 5] 5A to 5C are explanatory diagrams showing a manufacturing method of the rotor. [Figure 6] 1A is a time chart showing temperature changes at a first end and a second end of the adhesive during a heating process, and FIG. 1B is a time chart showing temperature changes at the center of the adhesive during a heating process. [Figure 7] 10A to 10C are explanatory diagrams showing a manufacturing method of a rotor in a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] <Motor generator configuration> An embodiment of the present invention will now be described with reference to Figures 1 to 6. First, the configuration of the motor generator 100 will be described.

[0017] 1, the motor generator 100 includes a shaft 10, a rotor 20, and a stator 60. In the following description, an axis around which the rotor 20 rotates is referred to as a rotation axis J. In addition, one direction along the rotation axis J is referred to as a first direction A, and a direction opposite to the first direction A is referred to as a second direction B.

[0018] The shape of the stator 60 is cylindrical overall. The central axis of the stator 60 coincides with the rotation axis J. The stator 60 includes a stator core 70 and a plurality of coils 80. The stator core 70 includes a stator core body 71 and a plurality of teeth 72. The shape of the stator core body 71 is generally cylindrical. The teeth 72 protrude from the inner circumferential surface of the stator core body 71. The teeth 72 extend in the direction along the rotation axis J from a first end on the first direction A side of the stator core body 71 to a second end on the second direction B side. The multiple teeth 72 are positioned at equal intervals from each other along the inner circumferential surface of the stator core body 71.

[0019] The stator 60 includes coils 80, the number of which is the same as the number of teeth 72. The coils 80 are wound around the teeth 72. In the direction along the rotation axis J, a portion of the coil 80 protrudes from a first end of the stator core 70 on the first direction A side. In addition, in the direction along the rotation axis J, a portion of the coil 80 protrudes from a second end of the stator core 70 on the second direction B side.

[0020] The rotor 20 includes a rotor core 30. The rotor core 30 is generally cylindrical in shape. The central axis of the rotor core 30 coincides with the rotation axis J. The outer diameter of the rotor core 30 is slightly smaller than the inner diameter of the stator 60. The rotor core 30 is located inside the stator 60. Note that in FIG. 1, the gap between the rotor core 30 and the stator 60 is omitted. Although not shown, the rotor core 30 is formed by stacking a plurality of generally disk-shaped electromagnetic steel plates.

[0021] The rotor core 30 has a fixing hole 31. The fixing hole 31 penetrates the rotor core 30 in a direction along the rotation axis J. The central axis of the fixing hole 31 coincides with the rotation axis J. The shaft 10 is located in the fixing hole 31. In the direction along the rotation axis J, a part of the shaft 10 protrudes from a first end of the rotor core 30 on the first direction A side. In addition, in the direction along the rotation axis J, a part of the shaft 10 protrudes from a second end of the rotor core 30 on the second direction B side. The shape of the shaft 10 is substantially a circular rod shape. The outer diameter of the shaft 10 is substantially the same as the diameter of the fixing hole 31. The outer peripheral surface of the shaft 10 is fixed to the inner peripheral surface of the fixing hole 31. Therefore, the central axis of the shaft 10 coincides with the rotation axis J.

[0022] As shown in FIG. 1, the rotor core 30 has a plurality of magnet holes 32. The magnet holes 32 penetrate the rotor core 30 in a direction along the rotation axis J. As shown in FIG. 2, the magnet holes 32 are located near the outer periphery of the rotor core 30. The plurality of magnet holes 32 are positioned at equal intervals along the outer periphery of the rotor core 30. As shown in FIG. 2, when the rotor 20 is viewed in a direction along the rotation axis J, the magnet holes 32 have a substantially rectangular shape. In this embodiment, the rotor core 30 has eight magnet holes 32.

[0023] As shown in FIG. 2, the rotor 20 includes a plurality of magnets 40 and a plurality of foamed resins 50. The rotor 20 includes the same number of magnets 40 as the number of magnet holes 32, that is, eight magnets 40. The magnets 40 are located in the magnet holes 32. The shape of the magnets 40 is a substantially rectangular plate. As shown in FIG. 2, when the rotor 20 is viewed in a direction along the rotation axis J, the dimension of the long side of the magnet 40 is substantially the same as the dimension of the long side of the magnet hole 32. Also, when the rotor 20 is viewed in a direction along the rotation axis J, the dimension of the short side of the magnet 40 is smaller than the dimension of the short side of the magnet hole 32. As shown in FIG. 1, in the direction along the rotation axis J, the magnet 40 extends from a first end on the first direction A side of the magnet hole 32 to a second end on the second direction B side. The magnet 40 is a permanent magnet. In this embodiment, an example of the magnet 40 is a neodymium magnet made of raw materials such as iron, neodymium, and boron.

[0024] As shown in FIG. 2, the rotor 20 includes a pair of foamed resins 50 for each magnet 40. That is, in this embodiment, the rotor 20 includes 16 foamed resins 50. One of the pair of foamed resins 50 is interposed between one of the two main surfaces of the magnet 40 and the inner wall surface of the magnet hole 32. The other of the pair of foamed resins 50 is interposed between the other of the two main surfaces of the magnet 40 and the inner wall surface of the magnet hole 32. Here, the main surface is the largest outer surface among the six outer surfaces of the magnet 40. As shown in FIG. 1, in the direction along the rotation axis J, the foamed resin 50 extends from a first end on the first direction A side of the magnet hole 32 to a second end on the second direction B side.

[0025] The foamed resin 50 is adhered to the inner wall surface of the magnet hole 32 and the outer surface of the magnet 40. Therefore, the foamed resin 50 holds the magnet 40 by adhering to the inner wall surface of the magnet hole 32 and the outer surface of the magnet 40. The foamed resin 50 is also compressed by the inner wall surface of the magnet hole 32 and the outer surface of the magnet 40. Therefore, the foamed resin 50 holds the magnet 40 by the repulsive force against the compression of the foamed resin 50. The foamed resin 50 includes a thermosetting resin 51. The thermosetting resin 51 has a property of being hardened at a temperature equal to or higher than a predetermined hardening temperature Z1. The foamed resin 50 is a hardened thermosetting resin 51 in which air bubbles are formed. Therefore, the volume of the foamed resin 50 is larger than the volume of only the thermosetting resin 51 without air bubbles. Examples of the thermosetting resin 51 include epoxy resin and phenolic resin. Here, the ratio of the volume of air bubbles to the unit volume of the foamed resin 50 is called the foaming ratio. The foaming rate of a first end 50A on the first direction A side of the foamed resin 50 is substantially the same as the foaming rate of a second end 50B on the second direction B side of the foamed resin 50. The foaming rates of the first end 50A and the second end 50B of the foamed resin 50 are also lower than the foaming rate of a center 50C of the foamed resin 50 in the direction along the rotation axis J.

[0026] The foaming resin 50 also includes an unfoamed foaming agent 52. The foaming agent 52 has a property of foaming at a temperature equal to or higher than a predetermined foaming temperature Z2. Here, the foaming temperature Z2 is a temperature higher than the curing temperature Z1. The foaming agent 52 contained in the foaming resin 50 is the foaming agent 52 contained in the adhesive 55 described below that remains without foaming. Examples of the foaming agent 52 include a substance that volatilizes at a foaming temperature Z2 or higher, a composition that chemically reacts at a foaming temperature Z2 or higher to generate gas, and a microcapsule with a gas sealed inside.

[0027] <Rotor manufacturing method> Next, a manufacturing method of the rotor 20 will be described. As shown in Fig. 3, first, a worker or the like performs a preparation step S10. In the preparation step S10, the worker or the like prepares an adhesive 55. The adhesive 55 includes an uncured thermosetting resin 51 and an unfoamed foaming agent 52. In the preparation step S10, the worker or the like also prepares a rotor core 30 and magnets 40.

[0028] 3, after the preparation step S10, the worker performs the application step S20. In the application step S20, the worker applies adhesive 55 to the entire areas of the two main surfaces of the magnet 40.

[0029] 3, after the application step S20, the worker or the like performs the drying step S30. In the drying step S30, the worker or the like dries the adhesive 55 to increase the viscosity of the adhesive 55. As a result, the adhesive 55 becomes difficult to peel off from the magnet 40.

[0030] As shown in FIG. 3, the worker performs the insertion step S40 after the drying step S30. As shown in FIG. 4, in the insertion step S40, the worker inserts the magnet 40 and the adhesive 55 into the magnet hole 32 of the rotor core 30. At this time, as shown in FIG. 5, the worker places the first end of the magnet 40 on the first direction A side in the same position as the first end of the magnet hole 32 on the first direction A side. In addition, the worker places the second end of the magnet 40 on the second direction B side in the same position as the second end of the magnet hole 32 on the second direction B side. In the same manner, the worker inserts the magnet 40 and the adhesive 55 into all the magnet holes 32 in the rotor core 30.

[0031] As shown in FIG. 3, the worker performs the heating step S50 after the insertion step S40. As shown in FIG. 4, in the heating step S50, the worker uses a heating device 200 to heat the adhesive 55. The heating device 200 includes an electromagnetic induction coil 210. The electromagnetic induction coil 210 is substantially spiral in shape. The inner diameter of the spiral of the electromagnetic induction coil 210 is larger than the outer diameter of the rotor core 30. Therefore, the heating device 200 allows the rotor core 30 to be disposed inside the electromagnetic induction coil 210. As shown in FIG. 5, the electromagnetic induction coil 210 includes a first end coil 210A, a second end coil 210B, and a center coil 210C. When the rotor core 30 is disposed inside the electromagnetic induction coil 210, the first end coil 210A is located near the first end of the rotor core 30 on the first direction A side. When the rotor core 30 is disposed inside the electromagnetic induction coil 210, the second end coil 210B is located near the second end of the rotor core 30 on the second direction B side. When the rotor core 30 is disposed inside the electromagnetic induction coil 210, the central coil 210C is located near the center of the rotor core 30 in the direction along the rotation axis J. Although the illustration is simplified, each of the first end coil 210A, the second end coil 210B, and the central coil 210C has a conductor wound therearound multiple times. The number of turns of the first end coil 210A is approximately the same as the number of turns of the second end coil 210B. The number of turns of the central coil 210C is greater than the number of turns of the first end coil 210A and the number of turns of the second end coil 210B.

[0032] As shown in FIG. 5, in the heating step S50, the worker places the rotor core 30 inside the electromagnetic induction coil 210 of the heating device 200. Then, the worker applies an AC current to the electromagnetic induction coil 210 of the heating device 200 to generate a magnetic field around the electromagnetic induction coil 210. At this time, the same AC voltage is applied to the first end coil 210A, the second end coil 210B, and the central coil 210C. Then, due to a temporal change in the magnetic field generated around the electromagnetic induction coil 210, an eddy current is generated inside the rotor core 30, and the rotor core 30 is heated. As a result, the entire adhesive 55 in the magnet hole 32 of the rotor core 30 is heated at the same time. At this time, the magnetic field generated near the first end coil 210A and the second end coil 210B is weaker than the magnetic field generated near the central coil 210C. Therefore, the amount of heat per unit time applied to the center 55C in the direction along the rotation axis J of the adhesive 55 is greater than the amount of heat per unit time applied to the first end 55A of the adhesive 55 on the first direction A side and the second end 55B of the adhesive 55 on the second direction B side. As a result, as shown in FIG. 6(b), the temperature of the center 55C in the direction along the rotation axis J of the adhesive 55 reaches the foaming temperature Z2 at time t1. That is, after time t1, the center 55C is heated to a temperature equal to or higher than the foaming temperature Z2. On the other hand, as shown in FIG. 6(a), the temperature of the first end 55A of the adhesive 55 on the first direction A side and the second end 55B of the adhesive 55 on the second direction B side rises more slowly than the temperature of the center 55C. Therefore, the temperature of the first end 55A and the second end 55B does not reach the foaming temperature Z2 even after time t1. However, the temperature of the first end 55A and the second end 55B reaches the hardening temperature Z1 at time t2. That is, after time t2, the first end 55A and the second end 55B are heated to a temperature equal to or higher than the curing temperature Z1 and lower than the foaming temperature Z2. Then, as shown in Figures 6(a) and 6(b), the worker continues to heat the entire adhesive 55 simultaneously until a predetermined specified period TX has elapsed from time t0 when heating of the adhesive 55 is started. As a result, foamed resin 50 is formed from the adhesive 55.

[0033] The specified period TX is determined as follows. First, a period during which the foaming agent 52 contained in the vicinity of the center 55C of the adhesive 55 is sufficiently foamed while the thermosetting resin 51 contained in the vicinity of the center 55C of the adhesive 55 is sufficiently cured is determined by experiments or the like when the center 55C of the adhesive 55 is heated at a temperature equal to or higher than the foaming temperature Z2. Also, a period during which the thermosetting resin 51 contained in the vicinity of the first end 55A and the second end 55B of the adhesive 55 is sufficiently cured is determined by experiments or the like when the first end 55A and the second end 55B of the adhesive 55 are heated at a temperature equal to or higher than the curing temperature Z1 and lower than the foaming temperature Z2. Then, the longer of the two periods is determined as the specified period TX.

[0034] <Action of this embodiment> In the heating step S50, the center 55C of the adhesive 55 is heated at a temperature equal to or higher than the foaming temperature Z2. Then, the foaming agent 52 contained in the adhesive 55 near the center 55C is foamed, and the volume of the adhesive 55 near the center 55C increases. Then, the gap between the outer surface of the magnet 40 and the inner wall surface of the magnet hole 32 is filled with the adhesive 55. Furthermore, the adhesive 55 is heated at a temperature equal to or higher than the foaming temperature Z2, i.e., at a temperature equal to or higher than the curing temperature Z1, and the thermosetting resin 51 contained in the adhesive 55 near the center 55C is cured. As a result, the magnet 40 is held in the magnet hole 32 by the foamed resin 50 formed from the adhesive 55.

[0035] <Effects of this embodiment> (1) In the heating step S50, the first end 55A and the second end 55B of the adhesive 55 are heated at a temperature equal to or higher than the curing temperature Z1 and lower than the foaming temperature Z2. Therefore, the foaming agent 52 contained in the vicinity of the first end 55A and the second end 55B of the adhesive 55 is not foamed, and the thermosetting resin 51 is cured. Then, the thermosetting resin 51 cured in the vicinity of the first end 55A and the second end 55B of the adhesive 55 functions as a plug for the magnet hole 32. As a result, even if the volume of the adhesive 55 increases in the vicinity of the center 55C, the adhesive 55 is blocked by the thermosetting resin 51 cured in the vicinity of the first end 55A and the second end 55B of the adhesive 55. As a result, even if the volume of the adhesive 55 increases in the vicinity of the center 55C, the adhesive 55 can be prevented from overflowing from the magnet hole 32.

[0036] (2) In the heating step S50, the entire adhesive 55 is heated at the same time. This allows the time period for heating the adhesive 55 to be shortened, compared to, for example, a case in which the first end 55A and the second end 55B of the adhesive 55 are heated first and then the center 55C of the adhesive 55 is heated.

[0037] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

[0038] In the above embodiment, the heating step S50 in the manufacturing method of the rotor 20 may be changed. For example, as shown in FIG. 7, a heating device 300 may be used instead of the heating device 200. The heating device 300 includes an electromagnetic induction coil 310, a first shielding material 320A, and a second shielding material 320B. The shape of the electromagnetic induction coil 310 is a substantially spiral shape. The shapes of the first shielding material 320A and the second shielding material 320B are substantially annular shapes. When the rotor core 30 is disposed inside the electromagnetic induction coil 310, the first shielding material 320A and the second shielding material 320B are located between the outer peripheral surface of the rotor core 30 and the inner peripheral surface of the electromagnetic induction coil 310. When the rotor core 30 is disposed inside the electromagnetic induction coil 310, the first shielding material 320A is located near the first end of the rotor core 30 on the first direction A side. When rotor core 30 is disposed inside electromagnetic induction coil 310, second shielding material 320B is located near a second end on the second direction B side of rotor core 30. One example of a material for first shielding material 320A and second shielding material 320B is ferrite as a magnetic material.

[0039] In the heating step S50 using the heating device 300, an alternating current is applied to the electromagnetic induction coil 310 of the heating device 300, generating a magnetic field around the electromagnetic induction coil 310. At this time, since the first shielding material 320A is located near the first end of the rotor core 30 on the first direction A side, the magnetic flux is shielded and absorbed by the first shielding material 320A. As a result, the magnetic field passing near the first end of the rotor core 30 on the first direction A side is weakened. Similarly, since the second shielding material 320B is located near the second end of the rotor core 30 on the second direction B side, the magnetic flux is shielded and absorbed by the second shielding material 320B. As a result, the magnetic field passing near the second end of the rotor core 30 on the second direction B side is weakened. Therefore, the amount of heat applied per unit time to the center 55C of the adhesive 55 in the direction along the rotation axis J can be made greater than the amount of heat applied per unit time to the first end 55A on the first direction A side of the adhesive 55 and the second end 55B on the second direction B side of the adhesive 55.

[0040] For example, as shown in FIG. 7, a cooling device 400 may be further used in the heating step S50. As a specific example, in the heating step S50, an operator may use the cooling device 400 to supply a refrigerant such as air to the first end 55A and the second end 55B of the adhesive 55, as shown by the dashed arrow in FIG. 7. This allows the amount of heat per unit time applied to the center 55C in the direction along the rotation axis J of the adhesive 55 to be greater than the amount of heat per unit time applied to the first end 55A on the first direction A side of the adhesive 55 and the second end 55B on the second direction B side of the adhesive 55. As a result, even in a situation where the entire adhesive 55 is heated to a temperature equal to or higher than the foaming temperature Z2 when only a heating device that heats the entire adhesive 55 is used, the temperature of the first end 55A and the second end 55B of the adhesive 55 can be lowered compared to the center 55C of the adhesive 55. When the first end 55A and the second end 55B of the adhesive 55 are cooled by the cooling device 400 or the like, the heating device 300 does not need to include the first shielding material 320A and the second shielding material 320B.

[0041] Furthermore, for example, when the cooling device 400 is used in the heating step S50, a temperature-adjustable heating furnace may be used instead of the heating devices 200 and 300. As a specific example, the worker places the rotor core 30 into which the magnets 40 and the adhesive 55 are inserted into the heating furnace, and heats the entire rotor core 30 evenly with the heating furnace. At this time, the worker may cool the first end 55A and the second end 55B of the adhesive 55 with the cooling device 400.

[0042] In the above embodiment, instead of the heating step S50 in the manufacturing method of the rotor 20, a first heating step S35 and a second heating step S55 may be adopted. As a specific example, the worker performs the first heating step S35 after the drying step S30 and before the inserting step S40. In the first heating step S35, the worker heats the first end 55A and the second end 55B of the adhesive 55 at a temperature equal to or higher than the curing temperature Z1 and lower than the foaming temperature Z2, thereby hardening the thermosetting resin 51 contained in the vicinity of the first end 55A and the second end 55B of the adhesive 55. In addition, the worker performs the second heating step S55 after the inserting step S40. In the second heating step S55, the worker heats the entire adhesive 55 at a temperature equal to or higher than the foaming temperature Z2, thereby hardening the thermosetting resin 51 while foaming the foaming agent 52 contained in the vicinity of the center 55C of the adhesive 55. In this case, since the thermosetting resin 51 contained in the adhesive 55 near the first end 55A and the second end 55B is cured in the first heating step S35, the foaming agent 52 contained in the adhesive 55 near the first end 55A and the second end 55B hardly foams in the second heating step S55. Therefore, in the second heating step S55, for example, a heating device that uniformly heats the entire adhesive 55 can be used.

[0043] In the above embodiment, the steps in the manufacturing method of the rotor 20 other than the heating step S50 may be changed. For example, in the application step S20, the worker may apply adhesive 55 to the inner wall surfaces of magnet hole 32 that face the two main surfaces of magnet 40. In this case, the worker does not need to apply adhesive 55 to the two main surfaces of magnet 40.

[0044] For example, in the preparation step S10, the worker or the like may prepare a plurality of adhesive sheets instead of the adhesive 55. Specifically, the adhesive sheet includes a strip-shaped sheet body and an adhesive containing an uncured thermosetting resin 51 and an unfoamed foaming agent 52. This adhesive is applied to the two main surfaces of the sheet body and then dried. In this case, the worker or the like may perform the insertion step S40 after the preparation step S10. Specifically, in the insertion step S40, the worker or the like may insert the magnet 40 and the pair of adhesive sheets into the magnet hole 32 of the rotor core 30 with the magnet 40 sandwiched between the pair of adhesive sheets.

[0045] In the above embodiment, the configuration of the rotor 20 may be changed. For example, the number of magnet holes 32 provided in the rotor core 30 may be changed. In this case, the numbers of magnets 40 and foamed resin 50 may be changed according to the number of magnet holes 32.

[0046] For example, the shapes of the magnet hole 32 and the magnet 40 may be changed. As a specific example, when the rotor 20 is viewed in the direction along the rotation axis J, the dimension of the long side of the magnet 40 may be smaller than the dimension of the long side of the magnet hole 32. In this case, a gap is generated between the outer surface of the magnet 40 other than the two main surfaces and the inner wall surface of the magnet hole 32, and the foamed resin 50 may be located in the gap. In other words, the adhesive 55 may be interposed between the outer surface of the magnet 40 other than the two main surfaces and the inner wall surface of the magnet hole 32. [Explanation of symbols]

[0047] A…First direction B…Second direction J: Rotation axis Z1…Curing temperature Z2…Foaming temperature 10…Shaft 20…Rotor 30…Rotor core 31…Fixing hole 32…Magnetic hole 40…Magnet 50…Foam resin 50A…First end 50B…2nd end 50C…center 51...Thermosetting resin 52...Foaming agent 55…Glue 55A…1st end 55B…2nd end 55C…Center 60…Stator 70…Stator core 71…Stator core body 72…Teeth 80…Coil 100...Motor generator 200…Heating device 210...Electromagnetic induction coil

Claims

1. a rotor core having a magnet hole passing through in a direction along a rotation axis; a magnet located within the magnet bore; and an adhesive interposed between the inner wall surface of the magnet hole and the outer surface of the magnet, the adhesive contains a foaming agent that foams at a temperature equal to or higher than a foaming temperature, and a thermosetting resin that hardens at a temperature equal to or higher than a hardening temperature that is lower than the foaming temperature, a heating step of heating a first end of the adhesive on a first direction side along the rotation axis and a second end of the adhesive on a second direction side opposite to the first direction to a temperature equal to or higher than the curing temperature and lower than the foaming temperature to harden the thermosetting resin, and heating a center of the adhesive in the direction along the rotation axis to a temperature equal to or higher than the foaming temperature. A method for manufacturing a rotor.

2. In the heating step, the adhesive is heated simultaneously throughout such that the amount of heat per unit time applied to the center of the adhesive is greater than the amount of heat per unit time applied to the first end and the second end of the adhesive. A method for manufacturing the rotor according to claim 1 .

3. In the heating step, the adhesive is heated as a whole at the same time, while the first end and the second end are cooled so that the temperatures of the first end and the second end are equal to or higher than the curing temperature and lower than the foaming temperature. A method for manufacturing the rotor according to claim 2.

4. The heating step comprises: a first heating step of heating the first end and the second end of the adhesive to a temperature equal to or higher than the curing temperature and lower than the foaming temperature to cure the thermosetting resin at the first end and the second end; A second heating step of heating the entire adhesive to a temperature equal to or higher than the foaming temperature after the first heating step. A method for manufacturing the rotor according to claim 1 .

5. a rotor core having a magnet hole passing through in a direction along a rotation axis; a magnet located within the magnet bore; and a foamed resin made of a thermosetting resin interposed between an inner wall surface of the magnet hole and an outer surface of the magnet, The foaming rate of the foamed resin at a first end on a first direction side along the rotation axis and at a second end on a second direction side opposite to the first direction is lower than the foaming rate of the foamed resin at a center in the direction along the rotation axis. Rotor.

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