Armature and method of manufacturing the same

Abstract

To provide an armature and an armature manufacturing method capable of suppressing the generation of stress in an iron core caused by the difference in thermal expansion between a permanent magnet and the iron core.SOLUTION: A rotor 11 includes an iron core 13 in which a plurality of magnet holes 15 penetrating in the axial direction along which the central axis L extends are arranged side by side along the peripheral edge, a plurality of permanent magnets 16 respectively inserted into the plurality of magnet holes 15, and a pair of plate members 14 fixed to the iron core 13 while covering the upper surface 13a and the lower surface 13b of the iron core 13. The permanent magnet 16 has an upper end surface 16a and a lower end surface 16b bonded to the pair of plate members 14 with an adhesive 21, respectively.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an armature in which permanent magnets are fixed in magnet holes provided in an iron core, and a method for manufacturing an armature. [Background technology]

[0002] A rotor for a rotating electric machine, such as that shown in Patent Document 1, is known as an armature of this type. Such a rotor (armature) includes a rotor core (iron core) having a plurality of magnet holes arranged circumferentially on the outer periphery, permanent magnets inserted into each magnet hole, and magnet fixing members for fixing the permanent magnets. The magnet fixing members are made of a thermosetting resin. The magnet fixing members fix the permanent magnets by filling each magnet hole so as to cover the entire permanent magnets and then hardening. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6705385 Summary of the Invention [Problem to be solved by the invention]

[0004] In the rotor described above, the magnet fixing member is filled between the permanent magnet and the rotor core in the magnet hole, and the permanent magnet and the rotor core have different thermal expansion coefficients. Therefore, for example, if the permanent magnet thermally expands more than the rotor core due to a change in rotor temperature, the rotor core will receive a load from the permanent magnet via the magnet fixing member, causing stress in the rotor core. [Means for solving the problem]

[0005] The means for solving the above problems and their effects will be described below. The armature that solves the above problem is an armature that includes an iron core having a plurality of magnet holes that penetrate in the axial direction along which the central axis extends, lined up along the periphery, a plurality of permanent magnets that are inserted into each of the magnet holes, and a pair of plate materials that are fixed to the iron core while covering both sides of the iron core in the axial direction, and the permanent magnets have both ends in the axial direction that are adhered to the pair of plate materials with an adhesive.

[0006] According to this configuration, the permanent magnet inserted into the magnet hole is held in the magnet hole by being adhered to a pair of plate materials at both ends (two locations) in the axial direction. As a result, a gap is formed between the permanent magnet and the iron core in the magnet hole. Therefore, when the permanent magnet and the iron core, which have different thermal expansion coefficients, thermal expansion occurs, the difference in thermal expansion between the permanent magnet and the iron core can be absorbed by the gap between the permanent magnet and the iron core. As a result, the iron core can be prevented from receiving a load from the permanent magnet, thereby preventing stress in the iron core caused by the difference in thermal expansion between the permanent magnet and the iron core.

[0007] A method for manufacturing an armature that solves the above-mentioned problem is a method for manufacturing an armature in which a plurality of permanent magnets are inserted into a plurality of magnet holes of an iron core, the magnet holes penetrating in the axial direction along which a central axis extends, and both sides of the iron core in the axial direction are covered with a pair of plate materials, and the method comprises an adhesive application step of applying adhesive to both end ends of the permanent magnet in the axial direction and at least one of the portions of the pair of plate materials corresponding to the both end ends, an insertion step of inserting the permanent magnet into the magnet holes, an adhesive step of bonding the both end ends of the permanent magnet to the pair of plate materials with the adhesive, and a joining step of joining the pair of plate materials to the iron core.

[0008] This configuration can provide the same effects as the above-described armature. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is an exploded perspective view of a rotor according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the rotor of FIG. 1. [Figure 3] FIG. 10 is a schematic cross-sectional view showing the state when a lower plate and an iron core are set in a lower jig. [Figure 4] 4 is a cross-sectional view showing a state in which permanent magnets are inserted into magnet holes in the iron core in FIG. 3. FIG. [Figure 5] FIG. 5 is a cross-sectional schematic diagram showing the state in which the iron core is welded to each of the upper and lower plates with the upper plate set on the lower jig in FIG. 4 and the upper plate, lower plate, and iron core sandwiched and pressed between the lower and upper jigs. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment in which the armature is embodied in a rotor will be described below with reference to the drawings. <Rotor 11> As shown in Figures 1 and 2, a rotor 11, which is an example of an armature of a rotating electrical machine, includes a cylindrical iron core 13 having a substantially circular first through hole 12 at the center for inserting a shaft (not shown), and a pair of annular plate members 14.

[0011] <Iron Core 13> 1 and 2, iron core 13 has a laminated structure in which multiple (e.g., several hundred) annular metal plates (electromagnetic steel plates) are stacked one on top of the other. A plurality of substantially rectangular magnet holes 15 are provided in the periphery of iron core 13, penetrating in the axial direction along which central axis L of iron core 13 extends. That is, multiple magnet holes 15 are provided in iron core 13, lined up along the periphery at equal intervals in the circumferential direction.

[0012] In the following description, the axial direction of the central axis L coincides with the up-down direction. That is, the up-down direction in the following description coincides with the up-down direction in FIG.

[0013] 1 and 2, the upper and lower surfaces of the core 13 are the upper surface 13a and the lower surface 13b, respectively. The upper and lower ends of each magnet hole 15 are open at the upper surface 13a and the lower surface 13b, respectively, of the core 13. A rectangular parallelepiped permanent magnet 16 is inserted into each magnet hole 15.

[0014] The vertical end faces (ends) of each permanent magnet 16 are upper end face 16a and lower end face 16b, respectively. Each permanent magnet 16 is arranged in magnet hole 15 with its long side oriented vertically. The vertical length of each permanent magnet 16 is the same as the vertical length of magnet hole 15.

[0015] Therefore, the upper end surface 16a of each permanent magnet 16 is flush with the upper surface 13a of the iron core 13, and the lower end surface 16b of each permanent magnet 16 is flush with the lower surface 13b of the iron core 13. Gaps 17 are formed between the wall surfaces 13c that form the magnet hole 15 in the iron core 13 and all of the side surfaces 16c of the permanent magnet 16. In other words, each permanent magnet 16 is inserted into the magnet hole 15 with almost no contact with the wall surfaces 13c of the iron core 13.

[0016] <Plate material 14> The pair of plate materials 14 is made of, for example, stainless steel. The pair of plate materials 14 has a substantially circular second through hole 18 in the center for inserting a shaft (not shown). The second through hole 18 has the same shape and diameter as the first through hole 12 of the iron core 13. The outer diameter of the pair of plate materials 14 is the same as the outer diameter of the iron core 13. In other words, the inner diameter and outer diameter of the pair of plate materials 14 match the inner diameter and outer diameter of the iron core 13, respectively.

[0017] The pair of plate materials 14 are fixed to the iron core 13 by, for example, welding, while covering the entire upper surface 13a and the entire lower surface 13b of the iron core 13, respectively. Of the pair of plate materials 14, one that covers the entire upper surface 13a of the iron core 13 is an upper plate 19, and the other that covers the entire lower surface 13b of the iron core 13 is a lower plate 20. The upper plate 19 and the lower plate 20 have the same configuration.

[0018] The upper end surface 16a and the lower end surface 16b of each permanent magnet 16 are adhered to the lower surface of the upper plate 19 and the upper surface of the lower plate 20, respectively, by adhesive 21. In this example, a microcapsule adhesive is used, for example. A microcapsule adhesive contains capsules with a curing agent enclosed in a main agent. A microcapsule adhesive is a type of adhesive in which adhesive strength is generated by the capsules being broken by pressure, causing the curing agent to mix with the main agent and harden.

[0019] <Method of manufacturing the rotor 11> Next, a method for manufacturing the rotor 11 configured as described above will be described. 3, when manufacturing rotor 11, first, a lower jig 22 is prepared. Lower jig 22 has a disk-shaped base 23 and a cylindrical protrusion 24 erected at the center of the upper surface of base 23. Protrusion 24 is configured so as to be insertable into first through hole 12 of core 13 and second through holes 18 of a pair of plate members 14.

[0020] Next, lower plate 20 is placed on base 23 so that protrusion 24 is inserted into second through hole 18 of lower plate 20, thereby setting lower plate 20 in a positioned state in lower jig 22. Next, iron core 13 is formed by stacking and joining multiple annular metal plates (electromagnetic steel plates). Next, iron core 13 is placed on lower plate 20 placed on base 23 so that protrusion 24 is inserted into first through hole 12 of iron core 13, thereby setting iron core 13 in a positioned state in lower jig 22.

[0021] Next, adhesive 21 is applied to the upper end surface 16a and the lower end surface 16b of the permanent magnet 16 (adhesive application step). In this case, since the adhesive 21 is made of a microcapsule adhesive, the adhesive application step may be performed in advance on a large number of permanent magnets 16. Next, as shown in Fig. 4, the permanent magnets 16 with adhesive 21 applied to their upper end surface 16a and lower end surface 16b are inserted sequentially into all of the magnet holes 15 (insertion step).

[0022] Next, as shown in Fig. 5, the upper plate 19 is placed on the upper surface 13a of the core 13 so that the protrusion 24 is inserted into the second through-hole 18 of the upper plate 19, thereby setting the upper plate 19 in a positioned state on the lower jig 22. Next, as shown in Fig. 5, a disk-shaped upper jig 25 is prepared. A recess 25a is formed in the center of the lower surface of the upper jig 25, into which the tip of the protrusion 24 of the lower jig 22 can be inserted.

[0023] 5, the upper jig 25 is placed on the upper plate 19 so that the tip of the protrusion 24 of the lower jig 22 is inserted into the recess 25a of the upper jig 25. Next, the upper jig 25 is pressed downward, thereby sandwiching and pressurizing the upper plate 19, the lower plate 20, and the iron core 13 between the base 23 of the lower jig 22 and the upper jig 25. The pressure applied at this time is also applied to the adhesive 21 between the upper end surface 16a of the permanent magnet 16 and the lower surface of the upper plate 19, and between the lower end surface 16b of the permanent magnet 16 and the upper surface of the lower plate 20.

[0024] As a result, adhesive force is generated in the adhesive 21 made of the microcapsule adhesive, and the adhesive 21 with this adhesive force bonds and fixes each permanent magnet 16 to the upper plate 19 and the lower plate 20 (bonding process). Subsequently, the upper plate 19, the lower plate 20, and the iron core 13 are preheated, and then the iron core 13 is joined to each of the upper plate 19 and the lower plate 20 by welding with heat applied from the welding torch 26 (joining process).

[0025] In this case, core 13 is welded to upper plate 19 and lower plate 20 at multiple locations in the circumferential direction. This results in rotor 11 as shown in Figures 1 and 2. After upper jig 25 is retracted, rotor 11 thus manufactured is removed from lower jig 22.

[0026] <Action of rotor 11> Next, the operation of the rotor 11 during use will be described. The rotor 11 is incorporated into a rotating electric machine for use. When the temperature of the rotor 11 rises due to operation of the rotating electric machine, the rotor 11 thermally expands. Since the permanent magnets 16 and the iron core 13 have different thermal expansion coefficients, the degree of thermal expansion differs between the permanent magnets 16 and the iron core 13.

[0027] However, in rotor 11 of this embodiment, permanent magnets 16 inserted into magnet holes 15 are held in magnet holes 15 by being adhered to a pair of plates 14 at two locations, upper end surface 16a and lower end surface 16b. In other words, rotor 11 is configured such that gaps 17 are formed between permanent magnets 16 and iron cores 13 in magnet holes 15.

[0028] Therefore, when permanent magnet 16 and iron core 13, which have different thermal expansion coefficients, thermally expand, the difference in thermal expansion between permanent magnet 16 and iron core 13 is absorbed by gap 17 between permanent magnet 16 and iron core 13. Therefore, it is possible to prevent iron core 13 from receiving a load from permanent magnet 16, and therefore it is possible to prevent stress in iron core 13 caused by the difference in thermal expansion between permanent magnet 16 and iron core 13.

[0029] Incidentally, if gap 17 between permanent magnet 16 and iron core 13 in magnet hole 15 is filled with a filler such as resin, iron core 13 will receive a load from permanent magnet 16 via the filler. As a result, stress is generated in iron core 13, and if stress concentrates in a weak, thin portion between the periphery of iron core 13 and magnet hole 15, there is a problem that this thin portion may be damaged.

[0030] This problem is particularly likely to occur when a neodymium magnet is used for the permanent magnet 16. This is because neodymium magnets have the property of contracting in a specific direction at high temperatures and expanding at low temperatures. In other words, for example, if a contracting neodymium magnet is inserted into the magnet hole 15 of the iron core 13, which expands at high temperatures, the iron core 13 will contract and expand at low temperatures, causing the iron core 13 to receive a large load from the neodymium magnet via the filler material.

[0031] According to the embodiment described above in detail, the following effects are achieved. (1) In the rotor 11, the upper end surface 16a and the lower end surface 16b of the permanent magnet 16 are bonded to the pair of plate members 14 by adhesive 21, respectively.

[0032] According to this configuration, permanent magnet 16 inserted into magnet hole 15 is held in magnet hole 15 by being adhered to pair of plate materials 14 at upper end surface 16a and lower end surface 16b (two locations). As a result, gap 17 is formed between permanent magnet 16 and iron core 13 in magnet hole 15. Therefore, when permanent magnet 16 and iron core 13, which have different thermal expansion coefficients, thermally expand, the difference in thermal expansion between permanent magnet 16 and iron core 13 can be absorbed by gap 17 between permanent magnet 16 and iron core 13. As a result, it is possible to prevent iron core 13 from receiving a load from permanent magnet 16, and therefore it is possible to prevent stress in iron core 13 caused by the difference in thermal expansion between permanent magnet 16 and iron core 13.

[0033] Furthermore, permanent magnet 16 is not joined to iron core 13, and gap 17 is formed between permanent magnet 16 and iron core 13 in magnet hole 15, so there is some play in the multiple laminated metal plates (electromagnetic steel plates) that make up iron core 13. Therefore, even if there is misalignment in some of the multiple metal plates that make up iron core 13, the misalignment of the metal plates can be eliminated by inserting a shaft (not shown) into first through hole 12 of iron core 13. Therefore, it is easy to insert a shaft (not shown) into first through hole 12 of iron core 13.

[0034] (2) In the manufacturing method of the rotor 11, the adhesive 21 is a microcapsule adhesive, and in the joining step, the pair of plate materials 14 and the iron core 13 are joined together under pressure. With this configuration, the microcapsule adhesive that constitutes adhesive 21 hardens and generates adhesive strength when pressure is applied, destroying the microcapsules. Therefore, the same pressure that is applied when pressing pair of plate materials 14 and iron core 13 together in the joining process can also be applied to adhesive 21. Therefore, the bonding process can be performed automatically by simply performing the joining process. As a result, the manufacturing efficiency of rotor 11 can be improved.

[0035] (3) Unlike the method for manufacturing the rotor of Patent Document 1, the method for manufacturing rotor 11 does not require covering and fixing the entire permanent magnets 16 with thermosetting resin. Therefore, the axial thickness of rotor 11 can be made thinner than that of the rotor of Patent Document 1. Furthermore, because no thermosetting resin is used to fix permanent magnets 16, it is not necessary to use thermal energy to harden the thermosetting resin or to hold permanent magnets 16 for a period of time until the thermosetting resin hardens. This contributes to reducing the manufacturing cost and time of rotor 11.

[0036] (Example of change) The above embodiment can be modified as follows: Furthermore, the above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0037] A pressure-sensitive adhesive may be used as the adhesive 21. A pressure-sensitive adhesive is a type of adhesive that does not harden under normal pressure, but hardens when pressure is applied for a predetermined period of time. The adhesive 21 may be a general adhesive that generates adhesive strength simply by being applied and allowed to dry naturally without the need for pressure.

[0038] In the adhesive application step, adhesive 21 may be applied to a position on the lower surface of the upper plate 19 corresponding to the upper end surface 16a of the permanent magnet 16 and to a position on the upper surface of the lower plate 20 corresponding to the lower end surface 16b of the permanent magnet 16. In this case, adhesive 21 may or may not be applied to the upper end surface 16a and the lower end surface 16b of the permanent magnet 16.

[0039] The iron core 13 may be formed by cutting a block of metal instead of by laminating multiple metal plates. The armature according to the above embodiment may be applied not only to the rotor 11 but also to the stator of a rotating electrical machine. [Explanation of symbols]

[0040] 11...Rotor as an example of an armature 12...First through hole 13...Iron core 13a…Top surface 13b…Bottom surface 13c...Wall 14...Plate material 15...Magnetic hole 16...Permanent magnet 16a…Top end surface 16b…Lower end surface 16c...side 17...Gap 18...Second through hole 19...Upper board 20…Lower board 21...Adhesive 22...Lower jig 23...Base 24...Protruding part 25...Upper jig 25a...recess 26...Welding torch L…Center axis line

Claims

1. an iron core having a plurality of magnet holes formed along a periphery thereof and penetrating in an axial direction along which a central axis extends; a plurality of permanent magnets inserted into the plurality of magnet holes, respectively; a pair of plate members fixed to the iron core in a state of covering both sides of the iron core in the axial direction, The permanent magnet has both end portions in the axial direction bonded to the pair of plate materials with an adhesive, a gap that is not filled with the adhesive is formed over the entire axial direction between a wall surface that forms the magnet hole in the iron core and all side surfaces of the permanent magnet.

2. A method for manufacturing an armature in which a plurality of permanent magnets are inserted into a plurality of magnet holes of an iron core, the magnet holes penetrating in an axial direction along a central axis line, and the iron core is covered on both sides in the axial direction with a pair of plate materials, an adhesive application step of applying an adhesive to at least one of both end portions of the permanent magnet in the axial direction and portions of the pair of plate members corresponding to the both end portions; an insertion step, which is carried out after the adhesive application step, of inserting the permanent magnet into the magnet hole so that a gap not filled with the adhesive is formed over the entire axial direction between a wall surface that forms the magnet hole in the iron core and all side surfaces of the permanent magnet; a bonding step, which is carried out after the inserting step, of bonding the two end portions of the permanent magnet to the pair of plate members with the adhesive; a joining step of joining the pair of plate materials and the iron core, the joining step being carried out after the bonding step; A method for manufacturing an armature, comprising:

3. 3. The method for manufacturing an armature according to claim 2, wherein in the bonding step, the two end portions of the permanent magnet and the pair of plate members are bonded with the adhesive by applying pressure.

4. 4. The method for manufacturing an armature according to claim 3, wherein in the joining step, the pair of plates and the iron core are joined together under pressure.

5. 5. The method for manufacturing an armature according to claim 4, wherein the pressure application in the bonding step and the pressure application in the joining step are carried out continuously.

6. 6. The method for manufacturing an armature according to claim 2, wherein the adhesive is a microcapsule adhesive.

Images