Method for manufacturing a resin-bonded permanent magnet and method for manufacturing a rotor

Abstract

This invention improves the accuracy of the total thickness of a permanent magnet and a resin coated on the permanent magnet, regardless of dimensional variation of the permanent magnet.　In this manufacturing method of a resin-coated permanent magnet, a liquid resin (26L) is coated on a permanent magnet (24) with screen printing to manufacture a resin-coated permanent magnet (22). In an arrangement step, the surface on one side of the permanent magnet (24) in the thickness direction is made to contact a support surface (46); a mask (50), in which an opening (52) is formed, is arranged on the other side of the permanent magnet (24) in the thickness direction, and the opening (52) is placed opposite of the permanent magnet (24). In a supply step, a resin (26L) is supplied to the surface on the other side of the mask (50) in the thickness direction. In a coating step, the resin (26L) is filled into the opening (52) with a squeegee (32) and coated on the permanent magnet (24). In the aforementioned arrangement step, the interval between the support surface (46) and mask (50) in the thickness direction is set to a constant dimension greater than or equal to the thickness of the permanent magnet, regardless of thickness-direction dimensional variation of the permanent magnet (24).

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a resin-coated permanent magnet and a method for manufacturing a rotor. [Background technology]

[0002] The method of manufacturing a rotor for a rotating electric machine described in Japanese Patent No. 6095827 includes the steps of applying adhesive to one surface of the magnetic material using masking or the like so that the total thickness of the magnetic material, which will become a permanent magnet after magnetization, and the adhesive is smaller than the radial width of the magnet insertion hole; positioning the rotor core so that its axial direction is horizontal, and inserting the magnetic material into the magnet insertion hole located vertically above it with the adhesive facing vertically upward; inserting the magnetic material into each of the magnet insertion holes, after which pressing the magnetic material against the inner wall surface on the outer periphery of each of the magnet insertion holes to position the magnetic material; and hardening the adhesive after the magnetic material has been positioned.

[0003] In the rotor manufacturing method described in JP 2019-68583 A, an adhesive is applied to a permanent magnet using an applicator, the adhesive is dried, the permanent magnet is placed in the magnet hole, and the adhesive is cured. The applicator includes a plunger pump equipped with a nozzle that dispenses the adhesive. The plunger pump is attached to an orthogonal axis robot and moves horizontally and vertically relative to the permanent magnet. When the adhesive is applied by this applicator, the plunger pump nozzle is moved so that the thickness of the adhesive at the application start end and application end end is smaller than the thickness of the application center. This prevents the adhesive thickness from becoming uneven. Summary of the Invention [Problem to be solved by the invention]

[0004] When applying resin to a magnet material using masking or the like as in the prior art described in Japanese Patent No. 6095827, coating cannot be performed in consideration of dimensional variations of the magnet material. That is, although dimensional variations in manufacturing occur in the dimensions of the magnet material, since the coating thickness of the coated material is determined by the thickness of the masking, the coating thickness of the coated material becomes constant. For this reason, the total thickness of the coated material such as resin and the magnet material varies according to the dimensional variations of the magnet material.

[0005] On the other hand, when adjusting the film thickness of a coated material by changing the gap amount between a nozzle and a permanent magnet by relatively moving the nozzle of a plunger pump with respect to the permanent magnet as in the prior art described in Japanese Patent Application Laid-Open No. 2019-68583, it is necessary to apply the coated material while leveling it at the tip of the nozzle. For this reason, convex portions, which are liquid pools of the coated material, are generated on the end side in the width direction of the nozzle, and a uniform coating surface cannot be obtained. Further, when moving the nozzle in a direction to reduce the above gap amount, since the amount of resin that loses its way further increases, there is a risk that the generation of the above convex portions is further promoted. Further, in the prior art described in Japanese Patent Application Laid-Open No. 2019-68583, not only does the tact time become longer compared to the prior art described in Japanese Patent No. 6095827, but also when applying an adhesive in an arbitrary pattern (shape), the shape of the nozzle is complicated and a large number of product numbers are required, so the manufacturing cost increases.

[0006] In view of the above facts, an object of the present disclosure is to obtain a method for manufacturing a resin-bonded permanent magnet and a method for manufacturing a rotor that can improve the accuracy of the total thickness of the resin applied to the permanent magnet and the permanent magnet regardless of dimensional variations of the permanent magnet.

Means for Solving the Problems

[0007] The method for manufacturing a resin-bonded permanent magnet according to the first aspect is a method for manufacturing a resin-bonded permanent magnet by applying a liquid resin to a permanent magnet by screen printing. In this method, one surface of the permanent magnet in the thickness direction is brought into contact with a support surface, and a mask having an opening is disposed on the other side of the permanent magnet in the thickness direction with the opening facing the permanent magnet. This is an arrangement step. A supply step is to supply the resin to the other surface of the mask in the thickness direction. A coating step is to fill the opening with the resin using a squeegee and apply it to the permanent magnet. In the arrangement step, regardless of the dimensional variation in the thickness of the permanent magnet, the distance in the thickness direction between the support surface and the mask is set to a constant dimension equal to or greater than the thickness of the permanent magnet.

[0008] According to the first aspect, in the arrangement step, one surface of the permanent magnet in the thickness direction is brought into contact with the support surface, a mask having an opening is disposed on the other side of the permanent magnet in the thickness direction with the opening of the mask facing the permanent magnet. In the supply step, the resin is supplied to the other surface of the mask in the thickness direction. In the coating step, the above resin is filled into the opening of the mask using a squeegee and applied to the permanent magnet. In the above arrangement step, regardless of the dimensional variation in the thickness of the permanent magnet, the distance in the thickness direction between the support surface of the permanent magnet and the mask is set to a constant dimension equal to or greater than the thickness of the permanent magnet. As a result, the dimension in the thickness direction between the other surface of the mask in the thickness direction and the support surface of the permanent magnet also becomes constant. Since the total thickness of the resin applied to the permanent magnet and the permanent magnet is determined by the dimension in the thickness direction between the other surface of the mask in the thickness direction and the support surface of the permanent magnet, the accuracy of the above total thickness can be improved by making this dimension constant.

[0009] The method for manufacturing a resin-bonded permanent magnet according to the second aspect is, in the first aspect, in the arrangement step, a flange portion having a height from the support surface equal to the constant dimension is disposed on the side of the permanent magnet, and one surface of the mask in the thickness direction is brought into contact with the other surface of the flange portion in the thickness direction.

[0010] According to the second aspect, in the placement step, by bringing one surface of the mask in the thickness direction into contact with the other surface of the earth retaining portion in the thickness direction, the placement height of the mask from the support surface of the permanent magnet is maintained at the constant dimension. Thereby, the interval in the thickness direction between the support surface of the permanent magnet and the mask can be made the constant dimension with a simple configuration.

[0011] The method for manufacturing a resin-bonded permanent magnet according to the third aspect is, in the second aspect, in the moving direction of the squeegee, by making a part of the other surface of the earth retaining portion in the thickness direction into an inclined surface, the height of a part of the earth retaining portion is made lower than the constant dimension.

[0012] According to the third aspect, in the moving direction of the squeegee, a part of the other surface of the earth retaining portion in the thickness direction is made into an inclined surface, so that the height of a part of the earth retaining portion is made lower than the constant dimension. The mask that comes into contact with this earth retaining portion deforms following the other surface of the earth retaining portion in the thickness direction when the squeegee moves. Thereby, the coating thickness of the resin applied to the permanent magnet can be changed in the moving direction of the squeegee.

[0013] The method for manufacturing a resin-bonded permanent magnet according to the fourth aspect is, in the third aspect, at both ends of the permanent magnet in the moving direction of the squeegee, making a part of the other surface of the earth retaining portion in the thickness direction into the inclined surface.

[0014] According to the fourth aspect, at both ends of the permanent magnet in the moving direction of the squeegee, a part of the other surface of the earth retaining portion in the thickness direction is made into an inclined surface. As a result, the height of the earth retaining portion becomes lower than the constant dimension at both ends of the permanent magnet, so that the coating thickness of the resin can be reduced at both ends of the permanent magnet. As a result, for example, it becomes easier to insert the resin-bonded permanent magnet manufactured according to the present disclosure into the magnet insertion hole of the rotor core.

[0015] The method for manufacturing a resin-bonded permanent magnet according to the fifth aspect is the same as any one of the first to fourth aspects. In the arranging step, a plurality of the permanent magnets are brought into contact with a plurality of the support surfaces, and a mask having a plurality of openings is arranged on the other side in the thickness direction with respect to the plurality of permanent magnets, and each of the openings is opposed to each of the permanent magnets.

[0016] According to the fifth aspect, in the arranging step, a plurality of the permanent magnets are brought into contact with a plurality of support surfaces. Then, a mask having a plurality of openings is arranged on the other side in the thickness direction with respect to the plurality of permanent magnets, and each opening is opposed to each permanent magnet. Thereafter, the above-described supply step and coating step are performed. As a result, a plurality of resin-bonded permanent magnets with high accuracy in the total thickness of the resin and the permanent magnet can be manufactured simultaneously.

[0017] The method for manufacturing a rotor according to the sixth aspect includes a manufacturing step of manufacturing a resin-bonded permanent magnet by the method for manufacturing a resin-bonded permanent magnet according to any one of the first to fifth aspects, and an inserting step of inserting the resin-bonded permanent magnet after the manufacturing step into a magnet insertion hole formed in a rotor core.

[0018] According to the sixth aspect, in the manufacturing step, a resin-bonded permanent magnet is manufactured by the method for manufacturing a resin-bonded permanent magnet according to any one of the first to fifth aspects. In the inserting step, the resin-bonded permanent magnet after the manufacturing step is inserted into the magnet insertion hole formed in the rotor core. In the above inserting step, since the resin-bonded permanent magnet having a constant total thickness of the resin and the permanent magnet is inserted into the magnet insertion hole, resin can be appropriately interposed at necessary locations between the permanent magnet and the inner wall surface of the magnet insertion hole without causing resin dripping or scraping and resulting in resin unevenness. As a result, the permanent magnet can be appropriately fixed to the rotor core. Moreover, since resin can be interposed only at the above necessary locations, the amount of resin used is reduced. Further, since the resin-bonded permanent magnet is manufactured by the method for manufacturing a resin-bonded permanent magnet according to any one of the first to fifth aspects, the same effects as any one of the first to fifth aspects can be obtained.

[0019] The manufacturing method of the rotor according to the seventh aspect includes a manufacturing process of manufacturing a resin-bonded permanent magnet by the manufacturing method of the resin-bonded permanent magnet according to any one of the first to fifth aspects, a semi-curing process of semi-curing the resin of the resin-bonded permanent magnet after the manufacturing process, an insertion process of inserting the resin-bonded permanent magnet after the semi-curing process into a magnet insertion hole formed in a rotor core, and a full-curing process of fully curing the resin of the resin-bonded permanent magnet inserted into the magnet insertion hole.

[0020] According to the seventh aspect, in the manufacturing process, a resin-bonded permanent magnet is manufactured by the manufacturing method of the resin-bonded permanent magnet according to any one of the first to fifth aspects. In the semi-curing process, the resin of the resin-bonded permanent magnet after the manufacturing process is semi-cured. In the insertion process, the resin-bonded permanent magnet after the semi-curing process is inserted into a magnet insertion hole formed in a rotor core. In the full-curing process, the resin of the resin-bonded permanent magnet inserted into the magnet insertion hole is fully cured. In the above insertion process, since a resin-bonded permanent magnet having a constant total thickness of the resin and the permanent magnet is inserted into the magnet insertion hole, the resin can be appropriately interposed at the necessary positions between the permanent magnet and the inner wall surface of the magnet insertion hole without causing resin dripping or scraping and resulting in resin deviation. As a result, the permanent magnet can be appropriately fixed to the rotor core. Moreover, since the resin can be interposed only at the above necessary positions, the amount of resin used is reduced. Further, since the resin-bonded permanent magnet is manufactured by the manufacturing method of the resin-bonded permanent magnet according to any one of the first to fifth aspects, the same effects as any one of the first to fifth aspects can be obtained.

[0021] The manufacturing method of the rotor according to the eighth aspect includes a manufacturing process of manufacturing a resin-bonded permanent magnet by the manufacturing method of the resin-bonded permanent magnet according to any one of the first to fifth aspects, a full-curing process of fully curing the resin of the resin-bonded permanent magnet after the manufacturing process, and an insertion process of inserting the resin-bonded permanent magnet after the full-curing process into a magnet insertion hole formed in a rotor core.

[0022] According to the eighth aspect, in the manufacturing process, the resin-bonded permanent magnet is manufactured by the manufacturing method of the resin-bonded permanent magnet according to any one of the first to fifth aspects. In this main curing process, the resin of the resin-bonded permanent magnet after the manufacturing process is main-cured. In the insertion process, the resin-bonded permanent magnet after the main curing process is inserted into the magnet insertion hole formed in the rotor core. In this insertion process, since the resin-bonded permanent magnet having a constant total thickness of the resin and the permanent magnet is inserted into the magnet insertion hole, the resin can be appropriately interposed at the necessary positions between the permanent magnet and the inner wall surface of the magnet insertion hole without causing resin dripping or scraping and resulting in resin deviation. As a result, the permanent magnet can be appropriately fixed to the rotor core. Moreover, since the resin can be interposed only at the above-mentioned necessary positions, the amount of resin used is reduced. Furthermore, since the resin-bonded permanent magnet is manufactured by the manufacturing method of the resin-bonded permanent magnet according to any one of the first to fifth aspects, the same effects as those of any one of the first to fifth aspects can be obtained.

Advantages of the Invention

[0023] As described above, in the manufacturing method of the resin-bonded permanent magnet and the manufacturing method of the rotor according to the present disclosure, the accuracy of the total thickness of the resin applied to the permanent magnet and the permanent magnet can be improved regardless of the dimensional variation of the permanent magnet.

Brief Description of the Drawings

[0024]

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Figure 16

Embodiments for Carrying Out the Invention

[0025] Hereinafter, with reference to FIGS. 1 to 11, a method for manufacturing a resin-bonded permanent magnet and a method for manufacturing a rotor according to an embodiment of the present disclosure will be described. In each figure, some reference numerals may be omitted for ease of viewing the drawings. First, the configuration of the rotor 10 manufactured by the method for manufacturing a rotor according to the present embodiment will be described.

[0026] The rotor 10 shown in FIGS. 1 and 2 is, as an example, a rotor of an inner-rotor type rotating electrical machine and is of a magnet-embedded type. This rotor 10 is composed of a rotor core 14 that is coaxially and integrally fixed to the rotating shaft 12 of the rotating electrical machine, and a plurality of resin-bonded permanent magnets 22 embedded in the rotor core 14. The rotor core 14 is composed of a laminated steel sheet in which a plurality of electromagnetic steel sheets 16 are laminated and is formed in a columnar shape. A fitting hole 18 penetrating the rotor core 14 in the axial direction is formed at the central portion of the rotor core 14. The above-mentioned rotating shaft 12 is press-fitted into this fitting hole 18, and the rotor core 14 is fixed to the rotating shaft 12.

[0027] In addition, a plurality (here, four) of magnet insertion holes 20 penetrating the rotor core 14 in the axial direction are formed in the outer peripheral portion of the rotor core 14. These magnet insertion holes 20 are arranged at equal intervals in the circumferential direction of the rotor core 14 and have a substantially rectangular shape with the circumferential direction of the rotor (specifically, the direction orthogonal to the radial direction of the rotor as viewed from the axial direction of the rotor) as the longitudinal direction. As described above, since the rotor core 14 is a laminate of a plurality of electromagnetic steel sheets 16, minute irregularities (steps) are generated on the inner wall surfaces of the respective magnet insertion holes 20 due to misalignment during lamination (see FIG. 2). Resin-bonded permanent magnets 22 are respectively arranged in these magnet insertion holes 20.

[0028] The resin-bonded permanent magnet 22 is composed of a permanent magnet 24 disposed in the magnet insertion hole 20 and a resin portion 26 interposed between the permanent magnet 24 and the inner wall surface of the magnet insertion hole 20. This resin-bonded permanent magnet 22 has a rectangular plate shape with the longitudinal direction of the rotor axis as its length and the radial direction of the rotor as its thickness direction. The permanent magnet 24 is a segment magnet made of a sintered magnet or the like, and is formed in a rectangular plate shape with the longitudinal direction of the rotor axis as its length and the radial direction of the rotor as its thickness direction. The cross-sectional shape of this permanent magnet 24, when viewed from the rotor axis direction, is rectangular with the longitudinal direction of the magnet insertion hole 20 as its length. This permanent magnet 24 is formed to be slightly smaller in size than the magnet insertion hole 20 when viewed from the rotor axis direction, and is insertable into the magnet insertion hole 20 in a non-contact manner.

[0029] The resin portion 26 is composed of a thermosetting resin applied to and cured on the surface of the permanent magnet 24 on the outer diameter side of the rotor. Examples of the type of this resin include epoxy resin and silicone resin. This resin portion 26 is formed in a quadrangular plate shape with the longitudinal direction of the rotor axis as its length and the radial direction of the rotor as its thickness direction. The thickness dimension of this resin portion 26 is set to be sufficiently smaller than the thickness dimension of the permanent magnet 24. This resin portion 26 is formed to be slightly smaller in size than the permanent magnet 24 when viewed from the outer diameter side of the rotor (outer side in the radial direction of the rotor), and there is no resin portion 26 at the outer peripheral edge portion of the permanent magnet 24.

[0030] In the above resin-bonded permanent magnet 22, the resin portion 26 is provided only on the surface of the permanent magnet 24 on the outer diameter side of the rotor (i.e., only on one side) among the surface on the outer diameter side and the surface on the inner diameter side of the rotor of the permanent magnet 24. Also, in this resin-bonded permanent magnet 22, the resin portion 26 is not provided on both end faces in the short side direction and both end faces in the long side direction of the permanent magnet 24. Note that the resin portion 26 may be provided only on the surface of the permanent magnet 24 on the inner diameter side of the rotor.

[0031] The resin-bonded permanent magnet 22 with the above configuration is configured to be lightly press-fitted into the magnet insertion hole 20 in a semi-cured state (so-called B-stage state) after the resin constituting the resin portion 26 is applied to the permanent magnet 24 and heated. That is, the size of the resin-bonded permanent magnet 22 when inserted into the magnet insertion hole 20 is set to a size that can be lightly press-fitted into the magnet insertion hole 20. The thickness dimension of the resin-bonded permanent magnet 22 at the time of this insertion is set to be slightly larger than the short-side dimension of the magnet insertion hole 20 when viewed in the rotor axis direction. In the present embodiment, as an example, at the stage where the resin is applied to the permanent magnet 24 to manufacture the resin-bonded permanent magnet 22, the total thickness of the permanent magnet 24 and the resin portion 26 becomes a size that can be press-fitted into the magnet insertion hole 20. Note that the resin-bonded permanent magnet 22 only needs to have the above size when inserted into the magnet insertion hole 20, and the timing of achieving the above size is not particularly limited.

[0032] When this resin-bonded permanent magnet 22 is lightly press-fitted into the magnet insertion hole 20, the resin portion 26 whose viscosity has increased due to the above semi-curing elastically deforms. As a result, the above light press-fitting is allowed. As the hardness of the semi-curing of the resin portion 26, for example, the heating temperature and heating time are adjusted so that the elastic modulus of the resin portion 26 is in the range of 10 MPa to 5000 MPa. Note that the hardness of the semi-curing of the resin portion 26 can also be adjusted by changing the types of the resin, curing agent, and curing accelerator, and the amount of the filler. As a method for stably maintaining the semi-cured state of the resin portion 26, for example, changing the combination of the resin and the curing agent to slow down the curing rate, or storing at a low temperature can be mentioned.

[0033] In the present embodiment, as an example, the width dimension (longitudinal dimension when viewed in the rotor axis direction) of the resin-bonded permanent magnet 22 is set to be smaller than the width dimension (longitudinal dimension when viewed in the rotor axis direction) of the magnet insertion hole 20. For this reason, in the state where the resin-bonded permanent magnet 22 is disposed in the magnet insertion hole 20, as shown in FIG. 1, gaps 28 are respectively formed between the resin-bonded permanent magnet 22 and both end portions in the circumferential direction of the rotor (both end portions in the longitudinal direction when viewed in the rotor axis direction) of the magnet insertion hole 20.

[0034] As shown in FIGS. 1 and 2, in the rotor 10 configured as described above, the surface on the inner diameter side of the permanent magnet 24 in the rotor is in direct contact with the portion on the inner diameter side of the inner wall surface of the magnet insertion hole 20. Further, in this rotor 10, the resin portion 26 of the resin-bonded permanent magnet 22 is in close contact with the portion on the outer diameter side of the inner wall surface of the magnet insertion hole 20. Specifically, in the present embodiment, the resin-bonded permanent magnet 22 is lightly press-fitted into the magnet insertion hole 20 in a state where the resin portion 26 is semi-cured, and then the resin portion 26 is reheated and fully cured. During this period until full curing, the semi-cured resin portion 26 is pressed against the inner wall surface of the magnet insertion hole 20 in the radial direction of the rotor, so that the resin portion 26 deforms corresponding to the unevenness of the inner peripheral surface. As a result, the resin portion 26 is in a configuration in close contact with the inner wall surface of the magnet insertion hole 20. To supplement this "close contact", generally when a semi-cured resin is reheated, the elastic modulus of the resin decreases. As a result, the resin portion 26 easily adheres to the inner wall surface of the magnet insertion hole 20. In the present embodiment, as an example, the heating temperature when the semi-cured resin portion 26 is reheated is set higher than the heating temperature when the resin portion 26 is semi-cured. Further, in the present embodiment, the contact rate between the resin portion 26 and the inner wall surface of the magnet insertion hole 20 is, for example, 70% or more.

[0035] Further, in the rotor 10 configured as described above, the residual stress in the peripheral portion (hole edge portion) of the magnet insertion hole 20 in the rotor core 14 is set to be relatively small (for example, 10 MPa or less). This is because when the semi-cured resin portion 26 is pressed against the inner wall surface of the magnet insertion hole 20 in the radial direction of the rotor and adheres to the unevenness of the inner wall surface of the magnet insertion hole 20, the deformation resistance of the resin portion 26 is small.

[0036] Further, the resin constituting the resin portion 26 does not contain a foaming component. This resin portion 26 is interposed between the surface on the outer diameter side of the permanent magnet 24 and the inner wall surface of the magnet insertion hole 20 in a non-foamed state. Further, as described above, in the present embodiment, since the resin-bonded permanent magnet 22 is lightly press-fitted into the magnet insertion hole 20 in a state where the resin portion 26 is semi-cured, it is configured to prevent or suppress resin dripping and scraping.

[0037] Next, a method for manufacturing a resin-bonded permanent magnet, which is a main part of this embodiment, and a method for manufacturing a rotor will be described. The method for manufacturing a resin-bonded permanent magnet according to this embodiment is a method for manufacturing a resin-bonded permanent magnet by applying a liquid resin to a permanent magnet by screen printing. In this method for manufacturing a resin-bonded permanent magnet, some steps are carried out using the screen printing machine 30 shown in FIG. 3. Hereinafter, for convenience of explanation, the directions indicated by the front-rear, left-right, and up-down arrows appropriately shown in FIGS. 3 to 11 are defined as the front-rear direction, left-right direction, and up-down direction of the screen printing machine 30.

[0038] The screen printing machine 30 includes a squeegee driving unit 34 that drives a squeegee 32. The squeegee driving unit 34 has, as an example, a front-rear driving unit 36 and an up-down driving unit 38. The squeegee 32 is supported by the front-rear driving unit 36 via the up-down driving unit 38. The front-rear driving unit 36 moves the squeegee 32 in the front-rear direction by driving an actuator (not shown). The up-down driving unit 38 moves the squeegee 32 in the up-down direction by driving an actuator (not shown).

[0039] Below the squeegee driving unit 34, inside the screen printing machine 30, a metal mask 50, which is a mask, is installed. A plurality (here, 10) of openings 52 are formed in the metal mask 50 at intervals from each other. The plurality of openings 52 are arranged in two rows in the front-rear direction as an example, and five openings 52 are provided in each row. Each opening 52 has a rectangular shape with the front-rear direction as its longitudinal direction. These openings 52 are formed in the metal mask 50 by methods such as etching, laser processing, and additive manufacturing. Note that the mask in the present disclosure is not limited to the metal mask 50, and a plate such as a mesh may also be used.

[0040] Below the metal mask 50, a plurality of permanent magnets 24 equal in number to the plurality of openings 52 (here, 10) are arranged. The plurality of permanent magnets 24 are arranged in two rows in the front-rear direction, similar to the plurality of openings 52. Each permanent magnet 24 is in the shape of a rectangular plate and is arranged below each opening 52 with the longitudinal direction in the front-rear direction and the plate thickness direction in the vertical direction. The dimensions of each permanent magnet 24 in the front-rear direction and the left-right direction are set larger than the dimensions of each opening 52 in the front-rear direction and the left-right direction, and a part of each permanent magnet 24 is exposed upward through each opening 52. These plurality of permanent magnets 24 are supported on a moving table 40 (see FIGS. 6 and 8; not shown in FIGS. 9 to 11) of the screen printing machine 30 via a jig 42 shown in FIG. 4.

[0041] The jig 42 includes a base portion 44 and a plurality (here, 6) of flange portions 48. The base portion 44 is formed in a rectangular plate shape by, for example, a metal plate with a constant thickness and is arranged with the vertical direction as the plate thickness direction. This base portion 44 is fixed on the moving table 40 of the screen printing machine 30. On the upper surface of this base portion 44, a plurality (here, 10) of support surfaces 46 for supporting the plurality of permanent magnets 24 are formed. Note that FIG. 4 shows a state where 9 permanent magnets 24 are arranged on the jig 42.

[0042] The plurality of support surfaces 46 are arranged in two rows in the front-rear direction as an example, and 5 support surfaces 46 are provided in each row. One surface (here, the lower surface) in the thickness direction of each permanent magnet 24 is in contact with each support surface 46. The portion where the plurality of support surfaces 46 are formed on the upper surface of the base portion 44 is, for example, a concave portion where the lower part of the permanent magnet 24 can be fitted, and when the permanent magnet 24 is fitted into the concave portion, the displacement of the permanent magnet 24 in the front-rear direction and the left-right direction with respect to the base portion 44 is restricted.

[0043] The plurality of retaining portions 48 are formed in a long plate shape by, for example, a metal plate having a constant thickness. With the front-rear direction as the longitudinal direction and the up-down direction as the plate thickness direction, they are arranged in parallel with each other at intervals in the left-right direction. The length dimension of each retaining portion 48 is set to be equal to the dimension in the front-rear direction of the base portion 44. The interval between adjacent retaining portions 48 is set to be equal to or slightly larger than the width dimension (dimension in the left-right direction) of the permanent magnet 24. These retaining portions 48 are detachably fixed to the base portion 44 by means such as screwing. Between the retaining portions 48 adjacent to each other in the left-right direction, two permanent magnets 24 are arranged at intervals in the front-rear direction, respectively.

[0044] The height of each retaining portion 48 from each support surface 46 is set to a constant dimension that is equal to or greater than the thickness of the permanent magnet 24. Although there are dimensional variations in the manufacture of the thickness of the permanent magnet 24, the height of each retaining portion 48 is set so that the upper surface of each retaining portion 48 is positioned above the upper surface of each permanent magnet 24 regardless of this dimensional variation. For example, a plurality of retaining portions 48 may be integrally connected and manufactured by a single metal plate. Also, for example, a plurality of retaining portions 48 may be integrally formed with the base portion 44.

[0045] When a plurality of permanent magnets 24 are set in the screen printing machine 30, the "arrangement process" in the present disclosure is carried out. In this arrangement process, for example, the moving table 40 of the screen printing machine 30 is moved to one side in the front-rear direction with respect to the metal mask 50, and a plurality of permanent magnets 24 are set on the jig 42 fixed to the upper surface of the moving table 40. At this time, the plurality of permanent magnets 24 are arranged on the plurality of support surfaces 46 formed on the jig 42, and the permanent magnets 24 are respectively positioned between the plurality of embankment portions 48. Each permanent magnet 24 is arranged in a state where the lower surface, which is one surface in the thickness direction, is in contact with each support surface 46. Then, the moving table 40 is moved below the metal mask 50 together with the jig 42, and the metal mask 50 is arranged above the plurality of permanent magnets 24 (the other side in the thickness direction with respect to each permanent magnet 24). The lower surface of the metal mask 50 is brought into contact with the upper surfaces of the plurality of embankment portions 48 located on the side of each permanent magnet 24, and the respective openings 52 face the respective permanent magnets 24 from above. In this state, the vertical interval TS (see FIGS. 6 and 8 to 11) between the support surface 46 of the permanent magnet 24 and the metal mask 50 in the vertical direction (the thickness direction of the permanent magnet 24) becomes a constant dimension equal to or greater than the thickness of the permanent magnet 24.

[0046] After the arrangement process, the "supply process" in the present disclosure is performed. In the supply process, for example, a liquid resin 26L (see FIGS. 6 to 11; not shown in FIG. 5) is supplied from a liquid agent supply unit (not shown) provided in the screen printing machine 30 to the upper surface of the metal mask 50. This resin 26L is the material of the resin portion 26 described above and is supplied to the upper surface of the metal mask 50 on one side (here, the rear side) in the front-rear direction with respect to the plurality of openings 52. In FIGS. 5 to 8, for the sake of easy viewing of the drawings, only one permanent magnet 24 and one opening 52 are shown respectively.

[0047] After the supply process, the "coating process" in the present disclosure is performed. In the coating process, the resin 26L supplied onto the upper surface of the metal mask 50 is filled into a plurality of openings 52 by the squeegee 32 and applied to the plurality of permanent magnets 24. Specifically, the squeegee 32 is lowered by the vertical drive unit 38 and contacts the upper surface of the metal mask 50 on one side (here, the rear side) in the front-rear direction with respect to the resin 26L supplied onto the upper surface of the metal mask 50. While maintaining the contact state, the squeegee 32 is moved from the rear side to the front side by the front-rear drive unit 36 (see the arrow M in FIGS. 5 to 8), so that the resin 26L is filled into each opening 52 as shown in FIGS. 7 and 8. As a result, the resin 26L is applied to each permanent magnet 24, the resin portion 26 described above is formed, and a plurality of resin-attached permanent magnets 22 are manufactured. In FIG. 7, the arrow F indicates the direction in which the resin 26L flows in the opening 52.

[0048] After the coating process, a removal process is performed. In the removal process, the moving table 40 of the screen printing machine 30 is moved to one side in the front-rear direction with respect to the metal mask 50, and the plurality of resin-attached permanent magnets 22 are removed from the jig 42. The above-described placement process, supply process, coating process, and removal process constitute the "manufacturing process" in the present disclosure. After the removal process, the "semi-curing process" in the present disclosure is performed. In the semi-curing process, the resin portion 26 of the resin-attached permanent magnet 22 is heated and semi-cured. For this heating, for example, an electric heater (not shown) is used. Thereafter, in the first cooling process, the resin-attached permanent magnet 22 is cooled. For this cooling, for example, a blower fan (not shown) is used.

[0049] Thereafter, in the insertion process, the resin-bonded permanent magnet 22 after the semi-curing process is inserted (here, lightly press-fitted) into the magnet insertion hole 20 of the rotor core 14. This insertion process is performed with the rotor core 14 and the resin-bonded permanent magnet 22 at room temperature. Thereafter, in the full-curing process, the resin portion 26 of the resin-bonded permanent magnet 22 after the insertion process is heated and fully cured. At this time, for example, the entire rotor 10 is heated using an electric heater (not shown). Thereafter, in the second cooling process, the rotor 10 is cooled. For this cooling, for example, a blower fan (not shown) is used. Thereafter, the rotor 10 is completed through an inspection process.

[0050] In this embodiment, after the above semi-curing process, the resin-bonded permanent magnet 22 is lightly press-fitted into the magnet insertion hole 20, but it is not limited thereto. The resin-bonded permanent magnet 22 may simply be inserted into the magnet insertion hole 20. For example, when the resin 26L constituting the resin portion 26 contains a foaming component, the resin-bonded permanent magnet 22 coated with the resin 26L so as to be smaller than the magnet insertion hole 20 is inserted into the magnet insertion hole 20, and then the full-curing process is performed. Thereby, the resin 26L foams and expands, so that the gap between the permanent magnet 24 and the magnet insertion hole 20 can be filled. In that case, the semi-curing process is omitted. Also, for example, when the viscosity of the resin 26L applied to the permanent magnet 24 is relatively high, the insertion process may be performed without going through the semi-curing process after the manufacturing process of the resin-bonded permanent magnet 22. In particular, when the rotor core 14 is arranged such that the axis of the rotor core 14 is horizontal and the above insertion process is performed, if the resin 26L has a certain viscosity, the problem of dripping does not occur.

[0051] Also, it is not limited to the configuration in which the full-curing process is performed after the insertion process as described above, and the full-curing process may be performed before the insertion process. That is, for example, when using a resin that has a certain degree of elasticity even after being fully cured (completely cured) as the above resin 26L, the full-curing process is performed after the manufacturing process of the resin-bonded permanent magnet 22, and then the resin-bonded permanent magnet 22 is inserted (press-fitted) into the magnet insertion hole 20 in the subsequent insertion process. By this press-fitting, the resin-bonded permanent magnet 22 can be fixed to the rotor core 14.

[0052] Next, the operations and effects of the present embodiment will be described.

[0053] According to the present embodiment, in the placement step, the permanent magnet 24 is placed on the support surface 46 formed on the jig 42, and the metal mask 50 having the opening 52 is placed above the permanent magnet 24, and the opening 52 of the metal mask 50 faces the permanent magnet. In the supply step, the resin 26L is supplied onto the upper surface of the metal mask 50. In the coating step, the resin 26L is filled into the opening 52 of the metal mask 50 by the squeegee 32 and applied to the permanent magnet 24.

[0054] In the above placement step, regardless of the dimensional variation in the thickness of the permanent magnet 24, the interval TS in the vertical direction (the thickness direction of the permanent magnet 24) between the support surface 46 of the permanent magnet 24 and the metal mask 50 is set to a constant dimension equal to or greater than the thickness of the permanent magnet 24. Thereby, the dimension in the vertical direction between the upper surface of the metal mask 50 and the support surface 46 of the permanent magnet 24 also becomes constant. Since the total thickness of the resin 26L applied to the permanent magnet 24 and the permanent magnet 24 is determined by the dimension in the vertical direction between the upper surface of the metal mask 50 and the support surface 46 of the permanent magnet 24, the accuracy of the above total thickness can be improved by making the dimension constant.

[0055] For example, as shown in FIGS. 9 to 11, when there are dimensional variations of T1, T2, and T3 in the thickness of the permanent magnet 24, in the present embodiment, the dimension in the vertical direction (T1 + t1, T2 + t2, T3 + t3) between the upper surface of the metal mask 50 and the support surface 46 of the permanent magnet 24 becomes constant, and the coating thicknesses t1, t2, and t3 of the resin 26L applied to each permanent magnet 24 are different from each other. In FIGS. 9 to 11, T2 > T1 > T3 and T2 + t2 = T1 + t1 = T3 + t3.

[0056] On the other hand, as in the comparative examples shown in FIGS. 12 to 14, in the configuration where the resin 26L is applied to the permanent magnet 24 with the upper surface of the permanent magnet 24 in contact with the lower surface of the metal mask 50, the coating thickness (t) of the resin 26L becomes constant, and the total thicknesses (T1 + t, T2 + t, T3 + t) of the resin 26L and the permanent magnet 24 become different from each other. In FIGS. 12 to 14, T2 > T1 > T3, and T2 + t > T1 + t > T3 + t.

[0057] As in the above comparative example, when the total thickness of the resin 26L and the permanent magnet 24, that is, the thickness of the resin - attached permanent magnet 22, does not become constant, the resin - attached permanent magnet 22 cannot be properly inserted into the magnet insertion hole 20 of the rotor core 14. In particular, in the configuration where the resin - attached permanent magnet 22 is press - fitted into the magnet insertion hole 20 after the resin part 26 is semi - cured as in the present embodiment, the press - fitting load varies greatly due to the variation in the thickness of the resin - attached permanent magnet 22. In this regard, in the present embodiment, since the thickness of the resin - attached permanent magnet 22 can be made constant, the resin - attached permanent magnet 22 can be press - fitted into the magnet insertion hole 20 as set.

[0058] Moreover, in the present embodiment, unlike the invention described in Japanese Patent Application Laid - Open No. 2019 - 68583 described in the background art section, equipment for adjusting the gap amount between the nozzle and the permanent magnet is not required, so the equipment can be simplified compared to that invention.

[0059] Also, in the present embodiment, in the semi - curing process after the coating process, the resin part 26 of the resin - attached permanent magnet 22 is semi - cured, and the resin - attached permanent magnet 22 after the semi - curing process is press - fitted into the magnet insertion hole 20. As a result, without causing resin dripping or scraping - off - induced resin bias, the resin part 26 can be appropriately interposed at the necessary locations between the permanent magnet 24 and the inner wall surface of the magnet insertion hole 20. As a result, the permanent magnet 24 can be properly fixed to the rotor core 14. Moreover, in the coating process, since the resin part 26 only needs to be applied to a part of the permanent magnet 24 so as to be interposed only at the above - mentioned necessary locations, the amount of resin used is reduced.

[0060] In addition, in the present embodiment, in the coating step, resin is coated only on one side (here, only the outer diameter side surface of the rotor) of the outer diameter side surface and the inner diameter side surface of the permanent magnet 24. Therefore, compared with the case where resin is coated on both of the above-mentioned surfaces, the coating step and the subsequent handling of the resin-bonded permanent magnet 22 become easier.

[0061] In addition, in the present embodiment, in the coating step, resin is coated only on the outer diameter side surface of the permanent magnet 24. Since the resin portion 26 made of this resin is appropriately interposed between the permanent magnet 24 and the inner wall surface of the magnet insertion hole 20, the centrifugal force acting on the permanent magnet 24 when the rotor 10 rotates is easily and appropriately applied to the inner wall surface of the magnet insertion hole 20. As a result, it is possible to prevent premature breakage of the rotor core 14 due to the above-mentioned centrifugal force concentrating on a part of the inner wall surface of the magnet insertion hole 20.

[0062] To supplement the above effects, in the present embodiment, after the insertion step and before the full-curing step, the semi-cured resin portion 26 is pressed against the inner wall surface of the magnet insertion hole 20 in the rotor radial direction, so that the resin portion 26 deforms corresponding to the unevenness of the inner peripheral surface. Thereby, the resin portion 26 adheres well to the unevenness of the inner wall surface of the magnet insertion hole 20. As a result, the centrifugal force acting on the permanent magnet 24 when the rotor 10 rotates is uniformly applied to the inner wall surface of the magnet insertion hole 20. Moreover, compared with the configuration in which the resin portion 26 also exists on the inner diameter side of the permanent magnet 24, the amount of the resin portion 26 can be reduced, which contributes to the weight reduction of the rotor 10 and the reduction of the manufacturing cost.

[0063] In addition, in the present embodiment, since the resin is applied to the permanent magnet 24, the workability is improved and the equipment is simplified as compared with, for example, a configuration in which an adhesive is applied to the inner wall surface of the magnet insertion hole of the rotor core. That is, when applying the adhesive to the inner wall surface of the magnet insertion hole, the coating equipment enters and coats the generally small hole, so that the equipment becomes complicated and expensive. Also, it becomes difficult to manage the coating amount of the adhesive. Furthermore, although it takes time and effort for setup change work, maintenance, cleaning, etc., and the equipment introduction cost is considered to be large, and there is also a problem of poor versatility, in the present embodiment, the above problems can be avoided. Also, for example, in a configuration in which the magnet insertion hole is filled with resin by injection molding, it is not economical because the resin yield is poor in principle, but in the present embodiment, it is economical because the amount of resin used can be reduced.

[0064] In addition, the resin-coated permanent magnet 22 is set to a size such that a gap 28 is formed between both ends in the circumferential direction of the rotor in the magnet insertion hole 20 in a state where it is disposed in the magnet insertion hole 20. For this reason, in the insertion process, when inserting the end portion of the resin-coated permanent magnet 22 into the magnet insertion hole 20 by gripping the end portion with the tip of the clamp, it is possible to insert the tip of the clamp into the gap 28. Thereby, the configuration of the clamp that grips the end portion of the resin-coated permanent magnet 22 can be simplified.

[0065] In the rotor 10 according to the present embodiment, the resin portion 26 interposed between the permanent magnet 24 and the inner wall surface of the magnet insertion hole 20 is deformed by being pressed against the inner wall surface of the magnet insertion hole 20 in the radial direction of the rotor in a semi-cured state, and the amount of deformation during the deformation is small. Thereby, since the residual stress in the peripheral portion of the magnet insertion hole 20 in the rotor core 14 is set to 10 MPa or less, deformation of the peripheral portion due to change over time can be suppressed, and premature breakage of the rotor core 14 accompanying the deformation can be prevented.

[0066] (Modification example) Next, a modified example of the above embodiment will be described with reference to FIGS. 15 and 16. In FIGS. 15 and 16, the same reference numerals are given to the same configurations as those in the above embodiment. In this modified example, in the front-rear direction, which is the moving direction of the squeegee 32, a part of the upper surface of the soil portion 48 is formed as an inclined surface, so that the height of a part of the soil portion 48 is lowered. Specifically, a part of the upper surface of the soil portion 48 is formed as an inclined surface 48S on both the front and rear ends of the permanent magnet 24 in the front-rear direction. The height of the middle portion of the soil portion 48 in the front-rear direction of the permanent magnet 24 is a constant dimension, and the height of both ends of the permanent magnet in the front-rear direction is lower than the above constant dimension.

[0067] In this modified example, in the front-rear direction (i.e., the moving direction of the squeegee 32), a part of the upper surface of the soil portion 48 is formed as an inclined surface 48S, so that the height of a part of the soil portion 48 is made lower than the above constant dimension. The metal mask 50 whose lower surface contacts the upper surface of the soil portion 48 deforms following the upper surface of the soil portion 48 when the squeegee 32 moves. Thereby, the coating thickness of the resin 26L applied to the permanent magnet 24 can be changed in the front-rear direction as shown in FIG. 16. In this modified example, since the coating thickness of the resin 26L decreases at both ends of the permanent magnet 24 in the front-rear direction (i.e., both ends in the longitudinal direction), it becomes easier to insert the resin-coated permanent magnet 22 into the magnet insertion hole 20 of the rotor core 14.

[0068] In the above embodiment, in the arrangement step, the plate-shaped soil portion 48 having a thickness equal to or greater than the thickness of the permanent magnet 24 is arranged on the side of the permanent magnet 24, but the present invention is not limited to this. For example, instead of the soil portion 48, a plurality of columnar members may be provided on the upper surface of the base portion 44, and the upper end surfaces of the plurality of columnar members may be brought into contact with the lower surface of the metal mask 50, so that the height from the support surface 46 of the permanent magnet 24 is maintained at a constant dimension equal to or greater than the thickness of the permanent magnet 24. Further, the soil portion 48 may be made movable in the height direction so as to be freely adjustable in height in order to cope with variations in various magnet thicknesses.

[0069] In addition, in the above-described embodiment, the rotor 10 is configured as an inner rotor. However, the rotor according to the present disclosure is not limited to this, and may be an outer rotor. Further, the rotor according to the present disclosure may be a magnet-embedded type, and its configuration can be appropriately changed.

[0070] In addition, the present disclosure can be implemented with various modifications without departing from the gist thereof. Needless to say, the scope of rights of the present disclosure is not limited to the above-described embodiment.

[0071] Further, the disclosure of Japanese Patent Application No. 2021-011482 filed on January 27, 2021 is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described in this specification are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually described as being incorporated by reference.

Claims

1. A method for manufacturing a resin-bonded permanent magnet by applying a liquid resin to a permanent magnet by screen printing to produce a resin-bonded permanent magnet, comprising: an arranging step of bringing one surface on one side in the thickness direction of the permanent magnet into contact with a support surface, disposing a mask having an opening on the other side in the thickness direction with respect to the permanent magnet, and opposing the opening to the permanent magnet; a supplying step of supplying the resin to the surface on the other side in the thickness direction of the mask; a coating step of filling the resin into the opening with a squeegee and applying it to the permanent magnet; characterized by having: In the arranging step, a method for manufacturing a resin-bonded permanent magnet in which the distance in the thickness direction between the support surface and the mask is set to a constant dimension equal to or greater than the thickness of the permanent magnet regardless of the dimensional variation in the thickness of the permanent magnet.

2. The method for manufacturing a resin-bonded permanent magnet according to claim 1, wherein in the arranging step, a flange portion having a height from the support surface equal to the constant dimension is disposed on the side of the permanent magnet, and one surface on one side in the thickness direction of the mask is brought into contact with the surface on the other side in the thickness direction of the flange portion.

3. The method for manufacturing a resin-bonded permanent magnet according to claim 2, wherein in the moving direction of the squeegee, a part of the surface on the other side in the thickness direction of the flange portion is formed as an inclined surface, so that a part of the height of the flange portion is made lower than the constant dimension.

4. The method for manufacturing a resin-bonded permanent magnet according to claim 3, wherein in the moving direction of the squeegee, a part of the surface on the other side in the thickness direction of the flange portion at both ends of the permanent magnet is formed as the inclined surface.

5. The method for manufacturing a resin-bonded permanent magnet according to any one of claims 1 to 4, wherein in the arranging step, a plurality of the permanent magnets are brought into contact with a plurality of the support surfaces, a mask having a plurality of openings is disposed on the other side in the thickness direction with respect to the plurality of permanent magnets, and each opening is opposed to each permanent magnet.

6. A manufacturing process for manufacturing a resin-bonded permanent magnet by the method for manufacturing a resin-bonded permanent magnet according to any one of claims 1 to 5, and an inserting step of inserting the resin-bonded permanent magnet after the manufacturing process into a magnet insertion hole formed in a rotor core, A method for manufacturing a rotor having.

7. A manufacturing process for manufacturing a resin-bonded permanent magnet by the method for manufacturing a resin-bonded permanent magnet according to any one of claims 1 to 5, and a semi-curing step of semi-curing the resin of the resin-bonded permanent magnet after the manufacturing process, An insertion step of inserting the resin-bonded permanent magnet after the semi-curing step into a magnet insertion hole formed in a rotor core; A full-curing step of fully curing the resin of the resin-bonded permanent magnet inserted into the magnet insertion hole; A method for manufacturing a rotor having the above steps.

8. A manufacturing process for manufacturing a resin-bonded permanent magnet by the method for manufacturing a resin-bonded permanent magnet according to any one of Claims 1 to 5; A full-curing step of fully curing the resin of the resin-bonded permanent magnet after the manufacturing process; An insertion step of inserting the resin-bonded permanent magnet after the full-curing step into a magnet insertion hole formed in a rotor core; A method for manufacturing a rotor having the above steps.

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