Manufacturing method of rotor

Abstract

To provide a manufacturing method of a rotor which can improve productivity of the rotor.SOLUTION: In a filling process, temperature of a rotor core 11 is raised by heat of a resin material 30 by filling a magnet housing hole 13 in which a magnet 20 is housed with the resin material 30 heated to predetermined temperature to be melted. In an arrangement process, temperature of end plates 40 is raised by heat of the heated rotor core 11 by arranging the end plates 40 on a first end surface 11a and a second end surface 11b of the rotor core 11 filled with the resin material 30. In a welding process, the end plates 40 are welded to the rotor core 11 when the temperature of the rotor core 11 and the end plate 40 is within a temperature range in use in the middle of lowering of the temperature of the rotor core 11 and the end plates 40.SELECTED DRAWING: Figure 7

Description

[Technical field]

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

[0002] Conventionally, a rotor for a rotating electric machine is known that includes a cylindrical rotor core having magnet accommodating holes, magnets accommodated in the magnet accommodating holes, and end plates welded to the rotor core. The magnets are fixed to the rotor core via a resin material filled in the magnet accommodating holes. The end plates are welded to both ends of the rotor core in the axial direction to prevent the magnets from jumping out of the magnet accommodating holes.

[0003] When a rotating electric machine is in use, the temperature of the entire rotor rises. Therefore, if the linear expansion coefficients of the rotor core and the end plates are different from each other, the deformation amounts of the rotor core and the end plates during thermal expansion will be different from each other. This will cause internal stress in the welded parts between the rotor core and the end plates, which may reduce the strength of the welded parts.

[0004] Patent Document 1 discloses a method for manufacturing a rotor in which a rotor core is cooled so as to reduce the temperature difference between both end faces of the rotor core when end plates are welded to both axial ends of the rotor core. In the method described in Patent Document 1, a thermosetting resin material is filled into magnet accommodating holes that accommodate magnets, and then the rotor core is heated to a temperature equal to or higher than the temperature at which the resin material thermosets. The rotor core is then cooled by blowing air so that the temperatures of both end faces of the rotor core are within the temperature range during use of the rotor. End plates are welded to both ends of the rotor core that have been cooled in this way so as to reduce the temperature difference between the two end faces, thereby suppressing a decrease in strength of the welded parts between the rotor core and the end plates. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-118567 Summary of the Invention [Problem to be solved by the invention]

[0006] In the method described in Patent Document 1, after the magnet accommodating holes are filled with resin material, the rotor core is heated to thermally harden the resin material. After the rotor core is cooled, end plates are welded to the rotor core. This rotor manufacturing process takes time, so there is room for improvement in terms of improving rotor productivity. [Means for solving the problem]

[0007] A manufacturing method of a rotor for solving the above problem includes a cylindrical rotor core having a plurality of magnet accommodating holes, magnets accommodated in the magnet accommodating holes, a thermoplastic resin material filled in the magnet accommodating holes and fixing the magnets to the rotor core, and end plates formed of a material having a different linear expansion coefficient from that of the rotor core and welded to axial ends of the rotor core, the manufacturing method including: a filling process in which the magnet accommodating holes in which the magnets are accommodated are filled with the resin material that has been heated to a predetermined temperature and melted, thereby raising the temperature of the rotor core by the heat of the resin material; an arrangement process in which the end plates are arranged on one end face in the axial direction of the rotor core filled with the resin material, thereby raising the temperature of the end plates by the heat of the heated rotor core; and a welding process in which the end plates are welded to the rotor core, and in the welding process, the end plates are welded to the rotor core when the temperatures of the rotor core and the end plates are lower than the predetermined temperature and are within the operating temperature range when the rotor is in use, while the temperatures of the rotor core and the end plates are decreasing.

[0008] According to the above-described method, the end plates are welded to the rotor core when the temperatures of the rotor core and the end plates are within the operating temperature range, thereby preventing a decrease in strength of the welded portions between the rotor core and the end plates.

[0009] Here, when the molten thermoplastic resin material is filled into the magnet accommodating holes, the rotor core is heated by the heat of the resin material. The end plates are placed on one end face of the heated rotor core, and are heated by the heat of the rotor core. Then, while the temperatures of the rotor core and the end plates are decreasing and the temperatures are within the operating temperature range, the end plates are welded to the rotor core. From the above, the heat of the molten resin material can be used to keep the temperatures of the rotor core and the end plates within the operating temperature range. This allows the magnet accommodating holes to be filled with resin material and the rotor core to be heated at the same time. Therefore, the productivity of the rotor can be improved.

[0010] A manufacturing method of a rotor for solving the above problem includes a cylindrical rotor core having a plurality of magnet accommodating holes, magnets accommodated in the magnet accommodating holes, a thermoplastic resin material filled in the magnet accommodating holes and fixing the magnets to the rotor core, and end plates formed of a material having a different linear expansion coefficient than the rotor core and welded to axial ends of the rotor core, the manufacturing method including: a filling process in which the magnet accommodating holes containing the magnets are filled with the resin material that has been heated to a predetermined temperature and melted, thereby raising the temperature of the rotor core by the heat of the resin material; an arrangement process in which the pre-heated end plates are arranged on one axial end face of the rotor core filled with the resin material; and a welding process in which the end plates are welded to the rotor core, and in the welding process, the end plates are welded to the rotor core when the temperatures of the rotor core and the end plates are lower than the predetermined temperature and are within the operating temperature range when the rotor is in use, while the temperatures of the rotor core and the end plates are decreasing.

[0011] According to the above-described method, the end plates are welded to the rotor core when the temperatures of the rotor core and the end plates are within the operating temperature range, thereby preventing a decrease in strength of the welded portions between the rotor core and the end plates.

[0012] Here, when the molten thermoplastic resin material is filled into the magnet accommodating holes, the rotor core is heated by the heat of the resin material. The end plates are arranged on one end surface of the rotor core in a preheated state. Then, while the temperatures of the rotor core and the end plates are decreasing and the temperatures are within the operating temperature range, the end plates are welded to the rotor core. From the above, the temperatures of the rotor core and the end plates can be brought into the operating temperature range by utilizing the heat of the molten resin material and the heat of the preheated end plates. This makes it possible to both fill the magnet accommodating holes with the resin material and raise the temperature of the rotor core. Also, the welding process can be started early, immediately after the arrangement process. Therefore, the productivity of the rotor can be improved. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a cross-sectional view showing a rotor manufactured by a rotor manufacturing method according to one embodiment. [Diagram 2] FIG. 2 is a plan view showing the rotor core of FIG. [Diagram 3] FIG. 3 is an enlarged plan view showing the rotor of FIG. [Figure 4] FIG. 4 is a cross-sectional view showing a molding apparatus for manufacturing the rotor of FIG. [Diagram 5] FIG. 5 is a cross-sectional view showing a state in which the magnet accommodating holes of the rotor core in FIG. 1 are filled with a resin material. [Figure 6] FIG. 6 is a cross-sectional view showing a state in which a first end plate and a second end plate are arranged on the rotor core of FIG. [Figure 7]FIG. 7 is a cross-sectional view showing a state in which a first end plate and a second end plate are welded to the rotor core of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, one embodiment of a method for manufacturing a rotor will be described with reference to FIGS. (Rotor 10) 1, the rotor 10 includes a rotor core 11, a plurality of magnets 20, a plurality of resin materials 30, and two end plates 40. The rotor 10 is a rotor used in, for example, an embedded magnet motor.

[0015] (Rotor core 11) Rotor core 11 has a substantially cylindrical shape and is formed, for example, by laminating a plurality of core pieces punched out from electromagnetic steel sheets.

[0016] Hereinafter, the axial direction of rotor core 11 will be simply referred to as the axial direction, the radial direction of rotor core 11 will be simply referred to as the radial direction, and the circumferential direction of rotor core 11 will be simply referred to as the circumferential direction.

[0017] The rotor core 11 has a first end face 11a and a second end face 11b located opposite to each other in the axial direction. The rotor core 11 has a central hole 12 into which the shaft 100 is inserted, and a plurality of magnet accommodating holes 13 in which the magnets 20 are accommodated. The plurality of magnet accommodating holes 13 are formed at intervals from one another in the circumferential direction.

[0018] The center hole 12 and the magnet accommodating holes 13 penetrate the rotor core 11 in the axial direction. That is, the center hole 12 and the magnet accommodating holes 13 are both open to the first end face 11a and the second end face 11b.

[0019] The rotor core 11 is fixed to the shaft 100 by being sandwiched in the axial direction between a flange 101 formed on the shaft 100 and a nut 102 screwed onto the shaft 100, with end plates 40 welded to both ends in the axial direction.

[0020] 2, the cross-sectional shape of magnet accommodating hole 13 perpendicular to the axial direction is a substantially rectangular shape having long and short sides. The cross-sectional shape of magnet accommodating hole 13 is uniform throughout the axial direction.

[0021] The rotor core 11 has a total of ten pairs of magnet accommodating holes 13 adjacent to each other in the circumferential direction. The pair of magnet accommodating holes 13 are formed in a V shape such that the distance between them in the circumferential direction decreases toward the radially outer portions. Each magnet accommodating hole 13 has a filled portion 13a filled with resin material 30 at both ends in the long side direction.

[0022] 1, a plurality of weld grooves 14 are formed on the outer circumferential surface of both axial ends of rotor core 11. Weld grooves 14 extend partially in the axial direction on the outer circumferential surface of rotor core 11, for example.

[0023] 3, the weld grooves 14 are formed at intervals in the circumferential direction of the rotor core 11. The weld grooves 14 are formed on the outer periphery of the rotor core 11, between the radially outer filling portions 13a of a pair of magnet accommodating holes 13.

[0024] (Magnet 20) The magnets 20 are housed one by one in each magnet accommodating hole 13. The magnets 20 are fixed to the rotor core 11 via the resin material 30 filled in the magnet accommodating hole 13.

[0025] The magnet 20 is, for example, a permanent magnet. 1, the magnet 20 has an elongated shape that is long in the axial direction. The length of the magnet 20 in the axial direction is shorter than the length of the rotor core 11 in the axial direction.

[0026] One axial end face of the magnet 20 is located, for example, more inward in the axial direction than the first end face 11a. The other axial end face of the magnet 20 opposite to the one axial end face is, for example, flush with the second end face 11b.

[0027] (Resin material 30) The resin material 30 is filled, for example, between the inner surface of the magnet accommodating hole 13 and the outer surface of the magnet 20 around the entire periphery of the magnet 20 .

[0028] The resin material 30 covers one end face of the magnet 20 in the axial direction, and is formed flush with the first end face 11a of the rotor core 11. The resin material 30 is, for example, a thermoplastic resin such as a liquid crystal polymer.

[0029] (End plate 40) The end plates 40 are welded to both axial ends of the rotor core 11 via beads B formed in the weld grooves 14.

[0030] The end plates 40 are formed in a disk shape corresponding to the shapes of both axial end faces of the rotor core 11. The end plates 40 have a through hole 40a communicating with the center hole 12.

[0031] The end plates 40 are formed of a material having a linear expansion coefficient different from that of the rotor core 11. For example, the linear expansion coefficient of the end plates 40 is larger than the linear expansion coefficient of the rotor core 11. For example, the end plates 40 are formed of a metal material such as stainless steel.

[0032] The end plate 40 is a general term for the first end plate 41 and the second end plate 42. The first end plate 41 and the second end plate 42 have the same shape.

[0033] The first end plate 41 covers the first end face 11a of the rotor core 11. Therefore, the first end plate 41 covers the openings of all the magnet accommodating holes 13 that open to the first end face 11a. The second end plate 42 covers the second end face 11b of the rotor core 11. Therefore, the second end plate 42 covers the openings of all the magnet accommodating holes 13 that open to the second end face 11b.

[0034] (Molding device 50) Next, a molding device 50 for filling the magnet accommodating hole 13 with the resin material 30 will be described. As shown in FIG. 4, the molding apparatus 50 includes a first mold 60 and a second mold 80 .

[0035] (1st type 60) The first mold 60 includes a first mold body 61 and a pallet 62 . The first mold body 61 has a support surface that supports the lower surface of the pallet 62 .

[0036] Inside the first mold body 61, for example, a first heater H1 that generates heat when electricity is applied is disposed. The pallet 62 is transported between the first die body 61 and the second die 80 while supporting the rotor core 11 .

[0037] The pallet 62 includes a base plate 63, a post 64 protruding from the center of the base plate 63, and a spacer 66 disposed on the upper surface of the base plate 63. The post 64 penetrates the spacer 66.

[0038] The base plate 63 and the spacer 66 are each formed into a flat plate shape. The post 64 is formed into a cylindrical shape. A plurality of through holes 63a are provided at intervals in the circumferential direction in a portion of the base plate 63 on the outer circumferential side of the post 64. The through holes 63a are covered with a spacer 66.

[0039] The post 64 is inserted into the central hole 12 of the rotor core 11. A plurality of engagement pins 65 are provided at the tip of the post 64 at intervals in the circumferential direction. The spacer 66 supports the second end surface 11b of the rotor core 11 into which the post 64 is inserted.

[0040] (2nd type 80) The second die 80 includes a second die body 81 and a gate plate 83. The second die body 81 and the gate plate 83 are, for example, configured as separate bodies.

[0041] The second mold body 81 is, for example, a movable mold configured to be able to advance and retreat with respect to the first mold body 61. The second mold body 81 has a sprue 82 through which the resin material 30 injected from an injection device (not shown) flows.

[0042] Inside the second mold body 81, for example, a second heater H2 that generates heat when energized is disposed. The gate plate 83 is disposed between the second die body 81 and the rotor core 11. The gate plate 83 has a runner 84 that communicates with the sprue 82, and a plurality of gates 85 that extend from the runner 84.

[0043] The runners 84 open to an upper surface of the gate plate 83. The runners 84 extend radially in the radial direction from the center of the gate plate 83. The gate 85 opens to a lower surface of the gate plate 83. The gate 85 communicates between an end of the runner 84 and the magnet accommodating hole 13.

[0044] A plurality of engagement holes 86 into which the plurality of engagement pins 65 of the post 64 engage are provided on the lower surface of the gate plate 83. The engagement pins 65 engage with the engagement holes 86, whereby the gate plate 83 is positioned relative to the pallet 62.

[0045] (Method of manufacturing rotor 10) The manufacturing method of the rotor 10 includes a magnet housing step, a mold clamping step, a filling step, a removal step, a placement step, and a welding step. The magnet housing step, mold clamping step, filling step, removal step, placement step, and welding step are performed in this order.

[0046] (Magnet storage process) 4, in the magnet accommodating step, the magnets 20 are accommodated in the magnet accommodating holes 13 of the rotor core 11 supported by the pallet 62. At this time, the lower surface of the magnet 20 is in contact with the upper surface of the spacer 66.

[0047] (Mold clamping process) In the mold clamping process, first, the pallet 62 supporting the rotor core 11 is placed on the support surface of the first mold body 61. Next, a gate plate 83 is placed on the first end face 11a of the rotor core 11. As a result, the entire first end face 11a of the rotor core 11 is covered by the gate plate 83. Thereafter, the first mold 60 and the second mold 80 are clamped together so as to sandwich the rotor core 11 in the axial direction.

[0048] In the mold clamping process, the first mold body 61 is heated by energizing the first heater H1, and the second mold body 81 is heated by energizing the second heater H2. The heating temperatures of the first mold body 61 and the second mold body 81 are set to, for example, the same temperature. The first mold body 61 and the second mold body 81 are heated to a temperature lower than the temperature of the resin material 30 that is heated to a predetermined temperature and melted in the filling process described below. More specifically, the first mold body 61 and the second mold body 81 are heated to a temperature lower than the temperature within the operating temperature range when the rotor 10 is used. The first mold body 61 and the second mold body 81 are heated to, for example, about 40°C. The operating temperature range is the temperature range when the rotor 10 as a whole is heated due to heat generation by the magnets 20 when the rotor 10 is used. The operating temperature range is, for example, 60°C to 100°C.

[0049] By heating the first mold body 61 and the second mold body 81, the second end face 11b of the rotor core 11 is heated via the pallet 62, and the first end face 11a of the rotor core 11 is heated via the gate plate 83. The temperature of the rotor core 11 immediately before heating by the first mold body 61 and the second mold body 81 is a temperature lower than a temperature within the operating temperature range, for example, room temperature. In this specification, "room temperature" refers to 20°C±15°C.

[0050] (filling process) 5, in the filling step, an injection device (not shown) fills the magnet accommodating hole 13 with resin material 30 via the second die 80 while the first die body 61 and the second die body 81 are heated to a temperature lower than the temperature within the operating temperature range. In the filling step, the resin material 30 heated to a predetermined temperature and melted is filled into the magnet accommodating hole 13 through a gate 85. The resin material 30 is injected from the injection device in a melted state, for example, heated to about 350°C.

[0051] When the magnet accommodating holes 13 are filled with the resin material 30, the temperature of the rotor core 11 is increased by the heat of the resin material 30. Therefore, the temperature of the rotor core 11 is increased by the heat of the resin material 30 and the heat of the first die 60 and the second die 80.

[0052] The temperature of the resin material 30 decreases from the time it is injected from the injection device until it reaches the magnet accommodating hole 13 via the second die 80. The rotor core 11 also rises in temperature due to the heat of the first die 60 and the second die 80, but the temperature of the rotor core 11 rises only due to the heat of the resin material 30 to a temperature within the operating temperature range or a temperature exceeding the operating temperature range.

[0053] (Removal process) In the removal process, the spacer 66 is pressed from below by a lifting member (not shown) inserted into the through hole 63a of the base plate 63. This causes the rotor core 11 to move together with the spacer 66 in a direction to come out of the post 64, whereby the rotor core 11 is removed from the post 64.

[0054] (Placement process) As shown in Fig. 6, in the arranging step, a first end plate 41 and a second end plate 42 are arranged on the first end face 11a and the second end face 11b of the rotor core 11 filled with the resin material 30, respectively. In the arranging step, for example, the rotor core 11 is placed on the second end plate 42, and the first end plate 41 is placed on the rotor core 11. By arranging the end plates 40 on the first end face 11a and the second end face 11b of the rotor core 11, the temperature of the end plates 40 is raised by the heat of the rotor core 11 raised in the filling step. Note that the temperature immediately before the end plates 40 are arranged on the first end face 11a and the second end face 11b of the rotor core 11 is lower than a temperature within the operating temperature range, and is, for example, room temperature.

[0055] The end plates 40 are disposed on the first end face 11a and the second end face 11b of the rotor core 11, for example, when the temperature of the resin material 30 filled in the magnet accommodating holes 13 is lower than the melting point and higher than the glass transition point, and the resin material 30 is in a soft rubber-like state. Therefore, the end plates 40 are disposed on the rotor core 11 in a state in which the resin material 30 maintains its shape inside the magnet accommodating holes 13.

[0056] (Welding process) 7, in the welding process, two welding torches 90 weld the first end plate 41 and the second end plate 42 to the rotor core 11. The welding torches 90 are, for example, torches for laser welding.

[0057] In the welding process, while the temperatures of the rotor core 11 and the end plates 40 are decreasing, the end plates 40 are welded to the rotor core 11 when the temperatures of the rotor core 11 and the end plates 40 are within the operating temperature range.

[0058] In the welding process, after the first end plate 41 is welded to the rotor core 11, the second end plate 42 is welded to the rotor core 11. The first end plate 41 is welded to the rotor core 11 when the temperatures of the rotor core 11 and the first end plate 41 are within the usage temperature range. The second end plate 42 is welded to the rotor core 11 when the temperatures of the rotor core 11 and the second end plate 42 are within the usage temperature range.

[0059] In the welding process, when the temperatures of rotor core 11 and end plates 40 are within the operating temperature range, end plates 40 are sequentially welded in the circumferential direction to a plurality of circumferentially spaced portions of rotor core 11. At this time, the outer periphery of end plate 40 is welded to the portion of the outer periphery of rotor core 11 between filling portions 13a located radially outward of the pairs of magnet accommodating holes 13.

[0060] The operation and effects of this embodiment will be described. (1) In the filling process, resin material 30 that has been heated to a predetermined temperature and melted is filled into magnet accommodating holes 13 that accommodate magnets 20, and the temperature of rotor core 11 is raised by the heat of resin material 30. In the arrangement process, end plates 40 are arranged on first end face 11a and second end face 11b of rotor core 11 filled with resin material 30, and the temperature of end plates 40 is raised by the heat of rotor core 11 that has been heated. In the welding process, while the temperatures of rotor core 11 and end plates 40 are decreasing, and the temperatures of rotor core 11 and end plates 40 are within the operating temperature range, end plates 40 are welded to rotor core 11.

[0061] According to the above method, when the temperatures of the rotor core 11 and the end plates 40 are within the operating temperature range, the end plates 40 are welded to the rotor core 11. This makes it possible to suppress a decrease in strength of the welded portions between the rotor core 11 and the end plates 40.

[0062] Here, when the molten thermoplastic resin material 30 is filled into the magnet accommodating holes 13, the rotor core 11 is heated by the heat of the resin material 30. The end plates 40 are placed on the first end face 11a and the second end face 11b of the heated rotor core 11, and are heated by the heat of the rotor core 11. Then, while the temperatures of the rotor core 11 and the end plates 40 are decreasing and the temperatures are within the operating temperature range, the end plates 40 are welded to the rotor core 11. From the above, the heat of the molten resin material 30 can be used to keep the temperatures of the rotor core 11 and the end plates 40 within the operating temperature range. This allows the magnet accommodating holes 13 to be filled with the resin material 30 and the rotor core 11 to be heated at the same time. Therefore, the productivity of the rotor 10 can be improved.

[0063] Furthermore, for example, when resin material 30 is a thermosetting resin, the entire rotor core 11 is heated to a temperature equal to or higher than the thermosetting temperature of resin material 30. For this reason, the higher the thermosetting temperature is above the temperature range during use, the longer it takes for the temperature of rotor core 11 to decrease to within the temperature range during use, or a process of cooling rotor core 11 becomes necessary.

[0064] In this regard, according to the above method, the temperature of rotor core 11 is raised by the heat of resin material 30 filled in magnet accommodating holes 13. As a result, the heat source that raises the temperature of rotor core 11 becomes part of rotor core 11, so the heat of resin material 30 is thermally conducted to the entire rotor core 11 immediately after resin material 30 is filled. This makes it difficult for rotor core 11 to be excessively heated. As a result, the difference between the temperature of rotor core 11 raised by the heat of resin material 30 and the temperature within the operating temperature range tends to be small. This therefore shortens the time it takes for the temperature of rotor core 11 to drop to a temperature within the operating temperature range. In addition, a process of cooling rotor core 11 is not required.

[0065] (2) In the filling process, the rotor core 11 is clamped in the axial direction between the first die 60 and the second die 80, and the resin material 30 is filled into the magnet accommodating hole 13 while the first die 60 and the second die 80 are heated to a temperature lower than the temperature within the operating temperature range.

[0066] According to the above method, when the resin material 30 is filled into the magnet accommodating hole 13, the rotor core 11 is sandwiched between the first die 60 and the second die 80. At this time, the rotor core 11 is heated by the first die 60 and the second die 80. Here, the first die 60 and the second die 80 are heated to a temperature lower than the temperature within the operating temperature range. Therefore, the entire rotor core 11 including the part away from the magnet accommodating hole 13 into which the resin material 30 is filled can be heated while preventing the temperature of the rotor core 11 from exceeding the operating temperature range. Therefore, the temperature of the rotor core 11 can be brought into the operating temperature range early. In addition, by heating the first die 60 and the second die 80, a decrease in the viscosity of the resin material 30 inside the second die 80 and inside the magnet accommodating hole 13 can be suppressed. Therefore, the resin material 30 can be suitably filled into the magnet accommodating hole 13. From the above, the productivity of the rotor 10 can be further improved.

[0067] (3) In the welding process, the end plates 40 are welded to the portions of the outer periphery of the rotor core 11 between the filled portions 13a of the pair of magnet accommodating holes 13. Since the filled portion 13a is filled with the resin material 30, the temperature of the outer periphery of the rotor core 11 near the filled portion 13a rises due to the heat of the resin material 30 before other portions. According to the above method, in the welding process, the end plates 40 are welded to the portions of the outer periphery of the rotor core 11 between the filled portions 13a in the pair of magnet accommodating holes 13. Therefore, the welding portions between the rotor core 11 and the end plates 40 can be heated early and then the welding process can be performed.

[0068] (4) In the filling process, resin material 30 is filled into magnet accommodating holes 13 from the first end face 11a side of rotor core 11. In the arrangement process, a first end plate 41 and a second end plate 42 are arranged on first end face 11a and second end face 11b of rotor core 11, respectively. In the welding process, the first end plate 41 is welded to rotor core 11 when the temperatures of rotor core 11 and first end plate 41 are within the operating temperature range. Thereafter, the second end plate 42 is welded when the temperatures of rotor core 11 and second end plate 42 are within the operating temperature range.

[0069] According to the above method, the first end plate 41 is disposed on the first end face 11a of the rotor core 11 on the side where the resin material 30 is filled. The second end plate 42 is disposed on the second end face 11b of the rotor core 11 on the opposite side to the side where the resin material 30 is filled. Here, the resin material 30 is filled into the magnet accommodating hole 13 from the first end face 11a side, so that the temperature of the rotor core 11 is likely to be higher on the first end face 11a side than on the second end face 11b side. Therefore, the first end plate 41 is likely to reach a temperature within the operating temperature range before the second end plate 42 due to the heat of the rotor core 11. According to the above method, in the welding process, the first end plate 41 is welded to the rotor core 11 before the second end plate 42. Therefore, even before the temperature of the second end plate 42 reaches the operating temperature range, the first end plate 41 can be welded to the rotor core 11 as long as the temperature of the first end plate 41 reaches the operating temperature range. Then, if the temperature of the second end plate 42 reaches the operating temperature range while the first end plate 41 is being welded to the rotor core 11, the second end plate 42 can be welded to the rotor core 11. From the above, when welding the first end plate 41 and the second end plate 42 to the rotor core 11, the welding process can be started before the temperatures of both the first end plate 41 and the second end plate 42 reach the operating temperature range.

[0070] (5) In the welding process, when the temperatures of rotor core 11 and end plates 40 are within the operating temperature range, end plates 40 are sequentially welded to a plurality of circumferentially spaced locations of rotor core 11 .

[0071] According to the above method, a decrease in strength of a plurality of welded portions between rotor core 11 and end plates 40 can be suppressed. <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.

[0072] In the welding step, welding between a plurality of circumferentially spaced portions of the rotor core 11 and the end plates 40 may be performed simultaneously using a plurality of welding torches 90 . In the arrangement step, the first end plate 41 and the second end plate 42 may be arranged on the rotor core 11 at the same time, or either the first end plate 41 or the second end plate 42 may be arranged on the rotor core 11 first.

[0073] In the welding step, the end plate 40 arranged on either the first end face 11a or the second end face 11b may be welded to the rotor core 11. In this case, the rotor 10 includes either the first end plate 41 or the second end plate 42.

[0074] In the welding step, any portion of the outer periphery of the rotor core 11 and the outer periphery of the end plate 40 may be welded to each other. In the filling step, the resin material 30 may be filled into the magnet accommodating hole 13 in a state where only one of the first die 60 and the second die 80 is heated to a temperature lower than the temperature within the usage temperature range.

[0075] In the filling step, the first die 60 and the second die 80 do not have to be heated. In this case, the temperature of the rotor core 11 is raised only by the heat of the resin material 30 filled in the magnet accommodating holes 13. Therefore, it is not necessary to raise the temperature of the rotor core 11 by a means other than the temperature rise caused by the heat of the resin material 30.

[0076] In the arranging step, the preheated end plates 40 may be arranged on the first end face 11a and the second end face 11b of the rotor core 11. At this time, the end plates 40 may be preheated to a temperature within the operating temperature range, or may be preheated to a temperature higher or lower than the operating temperature range. According to this method, when the molten thermoplastic resin material 30 is filled into the magnet accommodating holes 13, the rotor core 11 is heated by the heat of the resin material 30. The end plates 40 are arranged on the first end face 11a and the second end face 11b of the rotor core 11 in a preheated state. Then, while the temperatures of the rotor core 11 and the end plates 40 are decreasing, the end plates 40 are welded to the rotor core 11 while the temperatures are within the operating temperature range. From the above, the temperatures of the rotor core 11 and the end plates 40 can be kept within the operating temperature range by utilizing the heat of the molten resin material 30 and the heat of the preheated end plates 40. This allows the magnet accommodating holes 13 to be filled with the resin material 30 while simultaneously raising the temperature of the rotor core 11. Also, the welding process can be started early, immediately after the placement process, thereby improving the productivity of the rotor 10.

[0077] The end plates 40 may be made of a material having a linear expansion coefficient smaller than that of the rotor core 11 . The above embodiment includes the configurations described in the following supplementary notes.

[0078] [Appendix 1] A manufacturing method for a rotor including a cylindrical rotor core having a plurality of magnet accommodating holes, magnets accommodated in the magnet accommodating holes, a thermoplastic resin material filled in the magnet accommodating holes and fixing the magnets to the rotor core, and end plates formed of a material having a different linear expansion coefficient from that of the rotor core and welded to axial ends of the rotor core, the manufacturing method comprising: a filling step of filling the magnet accommodating holes in which the magnets are accommodated with the resin material that has been heated to a predetermined temperature and melted, thereby raising the temperature of the rotor core by the heat of the resin material; an arrangement step of arranging the end plates on one end face in the axial direction of the rotor core filled with the resin material, thereby raising the temperature of the end plates by the heat of the heated rotor core; and a welding step of welding the end plates to the rotor core, wherein in the welding step, while the temperatures of the rotor core and the end plates are decreasing, the end plates are welded to the rotor core when the temperatures of the rotor core and the end plates are lower than the predetermined temperature and are within the operating temperature range when the rotor is in use.

[0079] [Appendix 2] A manufacturing method for a rotor including a cylindrical rotor core having a plurality of magnet accommodating holes, magnets accommodated in the magnet accommodating holes, a thermoplastic resin material filled in the magnet accommodating holes and fixing the magnets to the rotor core, and end plates formed of a material having a different linear expansion coefficient from that of the rotor core and welded to axial ends of the rotor core, the manufacturing method comprising: a filling step of filling the magnet accommodating holes containing the magnets with the resin material that has been heated to a predetermined temperature and melted, thereby raising the temperature of the rotor core by the heat of the resin material; an arrangement step of arranging the preheated end plates on one axial end face of the rotor core filled with the resin material; and a welding step of welding the end plates to the rotor core, wherein in the welding step, while the temperatures of the rotor core and the end plates are decreasing, the end plates are welded to the rotor core when the temperatures of the rotor core and the end plates are lower than the predetermined temperature and are within the operating temperature range when the rotor is in use.

[0080] [Appendix 3] A manufacturing method for a rotor described in [Appendix 1] or [Appendix 2], wherein in the filling process, the rotor core is sandwiched between a first mold and a second mold in the axial direction, and the resin material is filled into the magnet accommodating hole while at least one of the first mold and the second mold is heated to a temperature lower than a temperature within the operating temperature range.

[0081] [Appendix 4] A method for manufacturing a rotor described in any one of [Appendix 1] to [Appendix 3], wherein a pair of adjacent magnet accommodating holes among the multiple magnet accommodating holes in the circumferential direction of the rotor core are formed so that the distance between them in the circumferential direction becomes smaller the radially outward of the rotor core, and the radially outward ends have filled portions in which the resin material is filled, and in the welding process, the end plate is welded to the outer periphery of the rotor core in a portion between the filled portions of the pair of magnet accommodating holes.

[0082] [Appendix 5] A method for manufacturing a rotor described in any one of [Appendix 1] to [Appendix 4], wherein the end plates include a first end plate and a second end plate welded to both ends of the rotor core in the axial direction, and in the filling process, the resin material is filled into the magnet accommodating holes from one side in the axial direction of the rotor core, and in the arranging process, the first end plate and the second end plate are arranged on the end face of the rotor core on the one side and the end face opposite to the end face on the one side, respectively, and in the welding process, the first end plate is welded to the rotor core when the temperatures of the rotor core and the first end plate are within the usage temperature range, and then the second end plate is welded when the temperatures of the rotor core and the second end plate are within the usage temperature range.

[0083] [Appendix 6] A method for manufacturing a rotor described in any one of [Appendix 1] to [Appendix 5], wherein, in the welding process, when the temperatures of the rotor core and the end plates are within an in-use temperature range, the end plates are sequentially welded to multiple locations spaced apart circumferentially around the rotor core. [Explanation of symbols]

[0084] B…Bead H1: First heater H2: Second heater 10...Rotor 11...Rotor core 11a...first end surface 11b…Second end surface 12...Center hole 13...Magnet receiving hole 13a...Filling section 14…Welding groove 20…Magnet 30…Resin material 40…End plate 40a...Through hole 41…First end plate 42…Second end plate 50…Molding device 60…Type 1 61…Type 1 main body 62…Palette 63…Base plate 63a...Through hole 64…Post 65...Engagement pin 66…Spacer 80…2nd type 81…Type 2 main body 82…Sprue 83…Gate plate 84…Runner 85…Gate 86…Engagement hole 90…Welding torch 100…Shaft 101...Flange 102...Nut

Claims

1. A manufacturing method for a rotor including a cylindrical rotor core having a plurality of magnet accommodating holes, magnets accommodated in the magnet accommodating holes, a thermoplastic resin material filled in the magnet accommodating holes and fixing the magnets to the rotor core, and end plates made of a material having a different linear expansion coefficient from that of the rotor core and welded to ends of the rotor core in an axial direction, the manufacturing method comprising: a filling step of filling the magnet accommodating holes with the resin material that has been heated to a predetermined temperature and melted, thereby increasing the temperature of the rotor core by the heat of the resin material; an arrangement step of arranging the end plate on one end surface in an axial direction of the rotor core filled with the resin material, thereby increasing a temperature of the end plate by heat of the rotor core having the increased temperature; a welding step of welding the end plates to the rotor core, In the welding step, while the temperatures of the rotor core and the end plates are decreasing, the end plates are welded to the rotor core when the temperatures of the rotor core and the end plates are lower than the predetermined temperature and within a temperature range during use of the rotor. A method for manufacturing a rotor.

2. A manufacturing method for a rotor including a cylindrical rotor core having a plurality of magnet accommodating holes, magnets accommodated in the magnet accommodating holes, a thermoplastic resin material filled in the magnet accommodating holes and fixing the magnets to the rotor core, and end plates made of a material having a linear expansion coefficient different from that of the rotor core and welded to ends of the rotor core in an axial direction, the manufacturing method comprising: a filling step of filling the magnet accommodating holes with the resin material that has been heated to a predetermined temperature and melted, thereby increasing the temperature of the rotor core by the heat of the resin material; a placement step of placing the preheated end plate on one end surface in an axial direction of the rotor core filled with the resin material; a welding step of welding the end plates to the rotor core, In the welding step, while the temperatures of the rotor core and the end plates are decreasing, the end plates are welded to the rotor core when the temperatures of the rotor core and the end plates are lower than the predetermined temperature and within a temperature range during use of the rotor. A method for manufacturing a rotor.

3. In the filling step, the rotor core is sandwiched between a first die and a second die in the axial direction, and the resin material is filled into the magnet accommodating hole in a state in which at least one of the first die and the second die is heated to a temperature lower than a temperature within the operating temperature range. A method for manufacturing a rotor according to claim 1 or 2.

4. a pair of the magnet accommodating holes adjacent to each other in a circumferential direction of the rotor core among the plurality of magnet accommodating holes are formed such that a distance between the magnet accommodating holes in the circumferential direction becomes smaller toward a radially outer portion of the rotor core, and the magnet accommodating holes have a filling portion at an outer end portion in the radial direction into which the resin material is filled, In the welding step, the end plates are welded to portions of an outer periphery of the rotor core between the filled portions of the pair of magnet accommodating holes. A method for manufacturing a rotor according to claim 1 or 2.

5. the end plates include a first end plate and a second end plate welded to both ends of the rotor core in an axial direction, In the filling step, the resin material is filled into the magnet accommodating hole from one side in an axial direction of the rotor core, In the arranging step, the first end plate and the second end plate are arranged on the one end surface and the end surface opposite to the one end surface of the rotor core, respectively; In the welding step, the first end plate is welded to the rotor core when temperatures of the rotor core and the first end plate are within the usage temperature range, and then the second end plate is welded to the rotor core when temperatures of the rotor core and the second end plate are within the usage temperature range. A method for manufacturing a rotor according to claim 1 or 2.

6. In the welding step, when temperatures of the rotor core and the end plates are within an operating temperature range, the end plates are sequentially welded to a plurality of portions of the rotor core spaced apart in a circumferential direction. A method for manufacturing a rotor according to claim 1 or 2.

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