Motor manufacturing method

Abstract

This motor manufacturing method comprises a step of preparing parts of an axial gap motor and a step of assembling the parts. The parts include: a rotor; a stator; a shaft that is the rotational axis of the rotor; a bearing for rotatably supporting the shaft; a case having a first plane on which the stator and the bearing are placed; and a shim disposed between the first plane and the bearing or between the first plane and the stator. The step of preparing the parts has: a step of obtaining a predicted length of the gap between the rotor and the stator in consideration of the actual dimension of the stator; and a step of determining the thickness of the shim on the basis of the difference between the design length of the gap and the predicted length thereof.

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a motor. This application claims priority based on Japanese Patent Application No. 2020-195500, filed on November 25, 2020, and incorporates by reference all of the contents of said Japanese application. [Background technology]

[0002] As shown in FIG. 10 of Patent Document 1, the axial gap type rotating electric machine of Patent Document 1 includes a case, a stator, a rotor, a shaft, and bearings. The case includes a cylindrical peripheral wall portion and a pair of disk-shaped plates. The pair of plates are attached to both ends of the peripheral wall portion. A through hole is formed in the center of the pair of plates. A shaft is provided in the through hole. The stator and rotor are arranged facing each other in the axial direction of the shaft inside the case. The stator is arranged on the plates. The rotor is provided with a gap between them. The shaft is the rotating axis of the rotor. The bearings support the shaft so that it can rotate freely. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-108323 Summary of the Invention

[0004] The method for manufacturing a motor according to the present disclosure includes: preparing parts for an axial gap motor; assembling the parts; The parts are: A rotor, a stator; a shaft that is a rotation axis of the rotor; a bearing that rotatably supports the shaft; a case having a first plane on which the stator and the bearing are mounted; a shim disposed between the first plane and the bearing or between the first plane and the stator; The step of preparing the part comprises: determining a predicted length of a gap between the rotor and the stator taking into account the actual dimensions of the stator; determining a thickness of the shim based on the difference between the design length of the gap and the predicted length. [Brief explanation of the drawings]

[0005] [Figure 1] FIG. 1 is a cross-sectional view showing an outline of a motor manufactured by the motor manufacturing method according to the first embodiment. [Figure 2] FIG. 2 is an enlarged schematic cross-sectional view of region A in FIG. [Figure 3] FIG. 3 is an enlarged schematic cross-sectional view showing another example of the region A in FIG. [Figure 4] FIG. 4 is a cross-sectional view showing an outline of a virtual motor. [Figure 5] FIG. 5 is an enlarged schematic cross-sectional view of region A in FIG. [Figure 6] FIG. 6 is an enlarged schematic cross-sectional view showing another example of the region A in FIG. [Figure 7] FIG. 7 is a graph showing the relationship between the load on the inner race of the first bearing and the amount of deviation of the inner race from the outer race of the first bearing. [Figure 8] FIG. 8 is a cross-sectional view showing an outline of a motor manufactured by the motor manufacturing method according to the second embodiment. [Figure 9] FIG. 9 is an enlarged schematic cross-sectional view of region A in FIG. [Figure 10] FIG. 10 is an enlarged schematic cross-sectional view showing another example of the region A in FIG. [Figure 11]FIG. 11 is a plan view of a shim provided in a motor manufactured by the motor manufacturing method according to the second embodiment, viewed from the first plate portion side. [Figure 12] FIG. 12 is a cross-sectional view showing an outline of a virtual motor. [Figure 13] FIG. 13 is an enlarged schematic cross-sectional view of region A in FIG. [Figure 14] FIG. 14 is an enlarged schematic cross-sectional view showing another example of the region A in FIG. [Figure 15] FIG. 15 is a diagram illustrating a method for manufacturing a motor according to the third embodiment. [Figure 16] FIG. 16 is a plan view of a shim provided in a motor manufactured by the motor manufacturing method according to the fourth embodiment, viewed from the first plate portion side. [Figure 17] FIG. 17 is a diagram illustrating a method for manufacturing a motor according to the fifth embodiment. [Figure 18] FIG. 18 is a diagram illustrating a method for manufacturing a motor according to the sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0006] [Problem to be solved by this disclosure] It is desirable to improve the manufacturability of axial gap motors.

[0007] An object of the present disclosure is to provide a motor manufacturing method that is excellent in manufacturability.

[0008] [Effects of this disclosure] The motor manufacturing method of the present disclosure is excellent in motor manufacturability.

[0009] <<Description of Embodiments of the Present Disclosure>> For example, an axial gap motor is manufactured through two assembly processes: a temporary assembly of the motor parts and a final assembly. The reason for temporary assembly of the parts is that it is difficult to assemble the gap length between the stator and rotor to the designed length if the parts are assembled only once. The designed gap length is the target value of the designed gap length determined based on the motor specifications. Therefore, the gap length of the motor manufactured through temporary assembly is measured. The difference between the measured gap length and the designed gap length is calculated. After the measured gap length is calculated, the motor is disassembled.

[0010] The parts are assembled using a shim with a thickness equal to the difference. The shim is placed between the bearing and the plate. By placing the shim, the bearing is moved away from the plate by the thickness of the shim. By moving the bearing away, the shaft supported by the bearing is shifted in the axial direction of the shaft. By shifting the shaft, the rotor is moved away from the stator. By moving the rotor away, the length of the gap becomes longer than the measured length. In other words, the length of the gap becomes longer than the measured length by the thickness of the shim. By making the thickness of the shim the same as the difference, the length of the gap can be made the designed length.

[0011] In the manufacturing method described above, the parts must be assembled twice, which makes the manufacturing process complicated.

[0012] The present inventors have conducted extensive research into motor manufacturing methods, and as a result have developed a manufacturing method that allows the length of the gap between the stator and rotor to be substantially the same as the designed length by assembling parts only once. First, embodiments of the present disclosure will be listed and described.

[0013] (1) A method for manufacturing a motor according to one aspect of the present disclosure includes: preparing parts for an axial gap motor; assembling the parts; The parts are: A rotor, a stator; a shaft that is a rotation axis of the rotor; a bearing that rotatably supports the shaft; a case having a first plane on which the stator and the bearing are mounted; a shim disposed between the first plane and the bearing or between the first plane and the stator; The step of preparing the part comprises: determining a predicted length of a gap between the rotor and the stator taking into account the actual dimensions of the stator; determining a thickness of the shim based on the difference between the design length of the gap and the predicted length.

[0014] The motor manufacturing method described above is excellent in the manufacturability of motors with excellent assembly precision. The manufacturing method described above can calculate the predicted length of the gap taking into account the actual dimensions before assembling the parts. In other words, the manufacturing method described above can calculate the difference between the predicted length of the gap and the designed length before assembling the parts.

[0015] The predicted gap length calculated taking into account the actual dimensions is a gap length calculated using the actual dimensions of the stator, as will be described in detail later. The predicted gap length calculated taking into account the actual dimensions is sometimes referred to as a first predicted length. In contrast, the predicted gap length can also be calculated from the design dimensions and dimensional tolerances of the parts. The predicted gap length calculated from the design dimensions and dimensional tolerances of the parts is a gap length calculated using the design dimensions and dimensional tolerances of each part excluding the shim. The predicted gap length calculated from the design dimensions and dimensional tolerances of the parts is sometimes referred to as a second predicted length. The first predicted length is more accurate than the second predicted length. In other words, the difference between the first predicted length and the design length is more accurate than the difference between the second predicted length and the design length.

[0016] The manufacturing method can assemble parts that include a shim having the exact same thickness as the gap, so the manufacturing method can assemble the parts only once to achieve the designed gap length.

[0017] (2) As one embodiment of the manufacturing method of the motor, If the predicted length is greater than the design length, In the step of assembling the parts, the shim may be disposed between the first plane and the stator.

[0018] The above motor manufacturing method is excellent in terms of manufacturability of motors with excellent assembly precision when the predicted length exceeds the designed length.

[0019] (3) As one embodiment of the manufacturing method of the motor, If the predicted length is less than the design length, In the step of assembling the parts, the shim may be disposed between the first plane and the bearing.

[0020] The above motor manufacturing method is excellent in terms of manufacturability of motors with excellent assembly precision when the predicted length is less than the designed length.

[0021] (4) As one embodiment of the manufacturing method of the motor, The step of determining the predicted length may further include determining the predicted length taking into account actual dimensions of the rotor, the shaft, and the bearing.

[0022] The above manufacturing method makes it possible to accurately determine the predicted length, and therefore makes it possible to manufacture a motor with excellent assembly precision.

[0023] (5) As one embodiment of the manufacturing method of the motor, The rotor is a rotor body in the form of an annular plate; At least one magnet fixed to the rotor body, the bearing is a radial bearing or an angular bearing having an inner race and an outer race, each of the inner race and the outer race has a first end surface facing the rotor body; the step of determining the predicted length further determines the predicted length by taking into consideration a deviation between the first end surface of the outer race and the first end surface of the inner race; The amount of deviation may be determined by taking into consideration the load acting on the inner race due to the weight of the shaft and the rotor, and the load acting on the inner race due to the attractive force of the magnet to the stator.

[0024] Depending on the weight of the shaft and rotor and the strength of the magnetic attraction, the first end face of the inner race may be misaligned with the first end face of the outer race. The difference between the predicted length and the designed length of the gap increases by the amount of misalignment. Therefore, even if parts are assembled that include a shim with a thickness equal to the difference between the predicted length and the designed length, which is determined by considering only the actual dimensions, it may be difficult to achieve the designed gap length.

[0025] The manufacturing method described above can calculate the predicted length by taking into account the amount of misalignment between the first end face of the inner race and the first end face of the outer race. This allows for accurate calculation of the predicted length, and therefore the accurate difference between the predicted length and the designed length. Therefore, the manufacturing method described above allows the gap length to be adjusted to the designed length by assembling the parts only once. This manufacturing method therefore offers excellent manufacturability for motors with excellent assembly precision.

[0026] (6) As one embodiment of the manufacturing method of the motor, The stator includes: a circular plate-shaped yoke; a plurality of columnar teeth arranged at intervals in the circumferential direction of the yoke, the yoke has a first surface that is in contact with the first plane, The teeth have end surfaces facing the rotor, In the step of determining the predicted length, the predicted length may be determined taking into consideration an actual dimension between the first surface of the yoke and the end surfaces of the teeth.

[0027] The above manufacturing method makes it possible to accurately determine the predicted length, and therefore makes it possible to manufacture a motor with excellent assembly precision.

[0028] (7) As one embodiment of the manufacturing method of the motor, The stator may include a stator core formed from a powder compact.

[0029] The above manufacturing method can manufacture a motor with excellent assembly precision, even when the motor includes a stator core made of a powder compact, which has lower dimensional precision than a stator core made of electromagnetic steel sheets.

[0030] (8) As one embodiment of the manufacturing method of the motor, The part may include a fastening member that fixes the first plane and the stator.

[0031] In the above manufacturing method, the fastening member can suppress misalignment between the stator and the first plane, making it possible to manufacture a motor with excellent assembly precision.

[0032] (9) As one embodiment of the manufacturing method of the motor, The rotor is a rotor body in the form of an annular plate; At least one magnet fixed to the rotor body, the rotor body has a first surface facing the magnet; the magnet has a first end surface facing the stator; In the process of determining the predicted length, the predicted length may be determined taking into account the actual dimension of the length between the first surface of the rotor body and the first end surface of the magnet in the rotor in which the rotor body and the magnet are fixed.

[0033] The above manufacturing method makes it possible to accurately determine the predicted length, and therefore makes it possible to manufacture a motor with excellent assembly precision.

[0034] (10) As one embodiment of the manufacturing method of the motor of (9), The number of the magnets is one, The magnet may have a circular ring shape.

[0035] The above manufacturing method uses a single magnet, which reduces the number of parts compared to when multiple magnets are used. This makes the manufacturing method superior in motor manufacturability. Furthermore, the manufacturing method can manufacture motors with excellent assembly precision.

[0036] (11) As one embodiment of the manufacturing method of the motor, In the step of assembling the parts, the shaft may be press-fitted into the rotor.

[0037] In the above manufacturing method, the rotor can be positioned relative to the shaft by press-fitting the shaft into the rotor. Therefore, the above manufacturing method can manufacture a motor with small rotor runout. Furthermore, the above manufacturing method can manufacture a motor with excellent assembly precision.

[0038] (12) As one embodiment of the manufacturing method of the motor, Repeating the process of assembling the parts; The step of determining the predicted length may determine the predicted length by taking into consideration average values ​​of actual dimensions of the stator, the rotor, the shaft, and the bearings for a number of pieces that is smaller than the number of motors to be manufactured.

[0039] The manufacturing method described above is excellent in terms of the manufacturability of multiple motors with excellent assembly precision. Therefore, the manufacturing method can manufacture multiple motors with minimal variation in performance. In particular, the manufacturing method described above is more likely to improve manufacturability than when the manufacturing method determines the predicted length by taking into account the average value of the actual dimensions, which is less than the number of motors to be manufactured.

[0040] (13) As one embodiment of the manufacturing method of the motor, It is preferable that the number of the stators and the number of the rotors are one each.

[0041] The above manufacturing method is excellent for the manufacturability of single stator / single rotor type motors, which have excellent assembly precision.

[0042] (14) As one embodiment of the manufacturing method of the motor, It is preferable that the number of the stators is two and the number of the rotors is one.

[0043] The above manufacturing method is excellent for the manufacturability of double stator / single rotor type motors, which have excellent assembly precision.

[0044] Details of the embodiments of the present disclosure The details of the embodiments of the present disclosure are described below. In the drawings, the same reference numerals indicate the same objects.

[0045] First Embodiment [Motor manufacturing method] A manufacturing method for the motor of the first embodiment will be described with reference to FIGS. 1 to 7. FIG. 1 is a cross-sectional view of a motor 1A manufactured by the manufacturing method of the motor of this embodiment, cut along a plane parallel to the axial direction of the shaft 4. The motor 1A of FIG. 1 is assembled using all parts, including a stator 2, a rotor 3, a shaft 4, a first bearing 51, a shim 6, and a case 7. FIG. 1 illustrates a single-stator, single-rotor axial gap motor as the manufactured motor 1A. A single-stator, single-rotor motor refers to a motor having one stator 2 and one rotor 3. An axial gap motor is a motor in which the stator 2 and rotor 3 face each other across a gap in the axial direction of the shaft 4. FIG. 4 shows a cross-sectional view of a hypothetical motor 1Z cut along a plane parallel to the axial direction of the shaft 4.

[0046] The method for manufacturing a motor of this embodiment includes a step of assembling the above-described parts of motor 1A shown in Fig. 1. Motor 1A manufactured by assembling the parts has a gap between stator 2 and rotor 3. The method for manufacturing a motor of this embodiment involves performing step A and step B in this order. In step A, the above parts are prepared. In process B, the above parts are assembled.

[0047] One of the features of the motor manufacturing method of this embodiment is that it satisfies the following requirements (a) and (b). (a) Step A includes steps A1 and A2. In step A1, a predicted length G0 shown in Figures 4 to 6 is calculated. The predicted length G0 is calculated taking into consideration the actual dimensions of specific parts excluding the shim 6 among the above-mentioned parts. In step A2, the thickness Ts of the shim 6 is determined. The thickness Ts is determined based on the difference between the design length G1 of the gap shown in FIGS. 1 to 3 and the predicted length G0 of the gap shown in FIGS. 4 to 6. The design length G1 is the target value of the design gap length determined based on the specifications of the motor 1A. The design length G1 has a certain tolerance. (b) In step B, a shim 6 having a thickness Ts determined before assembling the parts is placed in place.

[0048] First, the manufactured motor 1A will be described. Then, a method for manufacturing the motor 1A will be described. The motor manufacturing method of this embodiment takes as an example a case where the predicted length G0 is less than the designed length G1, as shown in FIGS. 2 and 5, or 3 and 6.

[0049] (Motor) <Stator> 1, the stator 2 is disposed on a first plane 71f of the case 7. The stator 2 includes a stator core 21 and a plurality of coils 25, as shown in FIG.

[0050] Stator core The stator core 21 includes a circular plate-shaped yoke 22 and a plurality of columnar teeth 23.

[0051] ··yoke The yoke 22 magnetically couples adjacent teeth 23 among the teeth 23 arranged in the circumferential direction of the yoke 22. As shown in FIG. 2, the yoke 22 has a planar first surface 22f, a planar second surface 22s, an outer peripheral surface, and an inner peripheral surface. The first surface 22f and the second surface 22s connect the outer peripheral surface and the inner peripheral surface. The first surface 22f is in contact with the first plane 71f. The second surface 22s is a surface connected to the side surface of the tooth 23.

[0052] Teeth As shown in FIG. 1, the teeth 23 are provided with coils 25. There are multiple teeth 23. The teeth 23 are arranged at predetermined intervals in the circumferential direction of the yoke 22. The teeth 23 protrude perpendicularly to the second surface 22s of the yoke 22 shown in FIG. 2. In this embodiment, the teeth 23 and the yoke 22 are formed as an integrated powder compact. The teeth 23 have the same shape and size. The teeth 23 are shaped like a rectangular pillar or a cylinder. Each tooth 23 has a side surface and an end surface 23a. The side surface is a surface that is connected to the second surface 22s of the yoke 22. The side surface protrudes from the second surface 22s of the yoke 22. The end surface 23a is located at the tip in the protruding direction. The end surface 23a is a surface that is connected to the side surface. The end surface 23a faces a magnet 35 of the rotor 3, which will be described later.

[0053] ·Hole As shown in FIG. 1 , the stator core 21 has holes. Fastening members 91 are provided in the holes. The fastening members 91 fix the stator core 21 to the first plane 71f. The fastening members 91 prevent misalignment between the stator 2 and the first plane 71f. An example of the fastening members 91 is a screw or a bolt. The holes are formed from the first plane 22f to the middle of the teeth 23. The number of holes may be less than the number of the teeth 23 or may be the same as the number of the teeth 23.

[0054] ·coil Each coil 25 has a cylindrical portion. The cylindrical portion is formed by winding a wire in a spiral shape. The coil 25 in this embodiment is an edgewise wound coil. A coated rectangular wire is used for the winding of the coil 25. Each coil 25 is disposed outside the tooth 23. The cross-sectional shape of the cylindrical portion of each coil 25 may correspond to the cross-sectional shape of the tooth 23, for example. The axial length of the cylindrical portion is slightly shorter than the length of the tooth 23. Note that FIG. 1 shows only the cylindrical portion, and both ends of the winding are not shown.

[0055] <Rotor> The rotor 3 is provided with a gap between it and the stator 2. The rotor 3 includes a rotor body 31 and at least one magnet 35.

[0056] Rotor body The rotor body 31 is rotatably supported relative to the case 7 by the shaft 4. The rotor body 31 is an annular member. A through hole is provided in the center of the rotor body 31. A third shaft portion 43 of the shaft 4, which will be described later, is provided in this through hole. In this embodiment, the rotor body 31 and the shaft 4 are combined by press-fitting the third shaft portion 43 into the through hole. By being press-fitted, the rotor 3 can be positioned relative to the shaft 4. Therefore, runout of the rotor 3 is likely to be reduced. The position of the rotor body 31 along the axial direction of the shaft 4 is determined by the rotor body 31 abutting against a second end face 42s of a second shaft portion 42, which will be described later.

[0057] As shown in FIG. 2, the rotor body 31 has a first surface 31f, a second surface 31s, an inner peripheral surface, and an outer peripheral surface. The first surface 31f and the second surface 31s connect the inner peripheral surface and the outer peripheral surface. The first surface 31f is the surface facing the stator 2. The second surface 31s is the surface facing the second bearing 55 shown in FIG. 1. The second bearing 55 will be described later. In this embodiment, the first surface 31f contacts the second end surface 42s. In this embodiment, a recess 32 is provided in the first surface 31f. The recess 32 opens toward the stator 2. A magnet 35 is fixed to the bottom surface 32a of the recess 32. The inner peripheral surface of the rotor body 31 contacts the third shaft portion 43 of the shaft 4. As shown in FIG. 1, the outer peripheral surface of the rotor body 31 does not contact the inner peripheral surface of the peripheral wall portion 73 of the case 7. A gap is provided between the outer peripheral surface of the rotor body 31 and the inner peripheral surface of the peripheral wall portion 73 of the case 7 .

[0058] ·magnet The magnet 35 is fixed to the rotor body 31. As shown in FIG. 2, adhesive 38 is used to fix the magnet 35. The number of magnets 35 may be one or more. If there is one magnet 35, the number of parts is fewer and the rotor 3 is easier to manufacture than when there are multiple magnets 35. This makes it easier to improve the manufacturability of the motor 1A. Furthermore, it is easier to manufacture a motor 1A with excellent assembly precision.

[0059] When there is one magnet 35, the magnet 35 has an annular shape. The south pole and north pole of each magnet 35 are arranged alternately in the circumferential direction. When there are multiple magnets 35, the specific number of magnets 35 is the same as the number of teeth 23. The multiple magnets 35 are arranged at equal intervals in the circumferential direction of the rotor body 31. Each magnet 35 has, for example, a flat plate shape. The planar shape of each magnet 35 is, for example, the same as the planar shape of the end face 23a of the tooth 23. Each magnet 35 is magnetized in the axial direction of the rotation shaft of the rotor 3. The magnets 35 adjacent to each other in the circumferential direction of the rotor body 31 have opposite magnetization directions. The rotating magnetic field generated by the stator 2 causes the magnet 35 to repeatedly attract and repel each tooth 23, thereby rotating the rotor 3.

[0060] The magnet 35 is a permanent magnet. Specific examples of the permanent magnet include a ferrite magnet, a neodymium magnet, a samarium-cobalt magnet, and a bonded magnet. Neodymium magnets and samarium-cobalt magnets have particularly strong magnetic forces.

[0061] <shaft> The shaft 4 is the rotation axis of the rotor 3. The shaft 4 is formed of a solid round bar. As shown in FIG. 1, the shaft 4 has multiple shaft portions with different diameters. The multiple shaft portions are integrally formed. The shaft 4 in this embodiment has, in order from the first plate portion 71 side to the second plate portion 72 side of the case 7, a first shaft portion 41, a second shaft portion 42, a third shaft portion 43, a fourth shaft portion 44, and a fifth shaft portion 45.

[0062] 1, the first shaft portion 41 is provided inside the first bearing 51. The outer peripheral surface of the first shaft portion 41 contacts the inner peripheral surface of the inner race 52 of the first bearing 51, as shown in FIG.

[0063] As shown in FIG. 1, the second shaft portion 42 has a diameter larger than the diameter of the first shaft portion 41. As shown in FIG. 2, the second shaft portion 42 has a first end face 42f and a second end face 42s. The first end face 42f is in contact with the first end face 52f of the inner race 52. The first end face 42f is not in contact with the outer race 53 of the first bearing 51. The second end face 42s is in contact with the first surface 31f of the rotor body 31.

[0064] As shown in FIG. 1, the third shaft portion 43 is provided in a through hole of the rotor body 31. As shown in FIG. 2, the outer peripheral surface of the third shaft portion 43 contacts the inner peripheral surface of the rotor body 31. As shown in FIG. 1, the third shaft portion 43 has a diameter smaller than the diameter of the second shaft portion 42. As shown in FIG. 2, the third shaft portion 43 has an end face 43a. The end face 43a contacts a first end face of an inner race 56 of the second bearing 55.

[0065] 1, the fourth shaft portion 44 is provided in the second bearing 55. The outer peripheral surface of the fourth shaft portion 44 contacts the inner peripheral surface of the inner race 56. The fourth shaft portion 44 has a diameter smaller than the diameter of the third shaft portion 43.

[0066] The fifth shaft portion 45 is provided within a through hole 72h. The through hole 72h is provided in a second plate portion 72, which will be described later. The outer peripheral surface of the fifth shaft portion 45 does not contact the inner peripheral surface of the second plate portion 72. The fifth shaft portion 45 has a diameter smaller than the diameter of the fourth shaft portion 44.

[0067] <First bearing, second bearing> The first bearing 51 and the second bearing 55 rotatably support the shaft 4. The first bearing 51 is attached to the first shaft portion 41. The second bearing 55 is attached to the fourth shaft portion 44. The first bearing 51 and the second bearing 55 may have the same configuration as each other, or may have different configurations.

[0068] The first bearing 51 is a radial bearing or an angular bearing. As shown in FIGS. 2 and 3 , the first bearing 51 has an inner race 52 and an outer race 53. The first bearing 51 in this embodiment is a ball bearing in which balls 54 are disposed between the inner race 52 and the outer race 53. The inner peripheral surface of the inner race 52 contacts the outer peripheral surface of the first shaft portion 41 of the shaft 4. The outer peripheral surface of the outer race 53 contacts a protrusion 71 a, which will be described later.

[0069] The inner race 52 has a first end face 52f and a second end face 52s. The outer race 53 has a first end face 53f and a second end face 53s. The first end face 52f and the first end face 53f face the rotor body 31. The first end face 52f contacts the first end face 42f. The first end face 53f does not contact the shaft 4. The second end face 52s and the second end face 53s face the shim 6. The second end face 52s does not contact the shim 6 or the case 7. In this embodiment, the second end face 52s contacts a fixing member (not shown). This fixing member mechanically fixes the first bearing 51 and the first shaft portion 41. Examples of this fixing member include a retaining ring or a shaft nut. When a shaft nut is used as the fixing member, it is preferable to form a threaded portion on the outer circumferential surface of the first shaft portion 41. This fixing member is not necessarily required. In this case, the inner race 52 and the first shaft portion 41 are fixed by being fitted together. The second end face 53s is in contact with the shim 6. FIG. 2 shows an example in which the first end face 52f and the first end face 53f are not misaligned along the axial direction of the first bearing 51. FIG. 3 shows an example in which the first end face 52f and the first end face 53f are misaligned along the axial direction of the first bearing 51. As will be described in detail later, the first end face 52f and the first end face 53f may also be misaligned along the axial direction of the first bearing 51.

[0070] The second bearing 55 is a radial bearing or an angular bearing. The second bearing 55 has the same configuration as the first bearing 51. That is, as shown in FIGS. 2 and 3 , the second bearing 55 has an inner race 56 and an outer race 57. The inner peripheral surface of the inner race 56 contacts the outer peripheral surface of the fourth shaft portion 44. The outer peripheral surface of the outer race 57 contacts the inner peripheral surface of the recess 72a. The recess 72a is provided in the second plate portion 72 of the case 7. The inner race 56 and the outer race 57 each have a first end face and a second end face. Each first end face faces the rotor body 31. The first end face of the inner race 56 does not contact the rotor body 31 but contacts the end face 43a. The second end face of the inner race 56 does not contact the elastic member 8 or the case 7. The second end face of the inner race 56 may or may not contact a fixed member similar to the first bearing 51. This is because the outer race 57 is pressed toward the rotor 3 by the elastic member 8. A first end face of the outer race 57 is not in contact with the rotor 3 or the shaft 4. A second end face of the outer race 57 faces the elastic member 8. The second end face of the outer race 57 is in contact with the elastic member 8.

[0071] <Elastic member 8> The elastic member 8 presses the second bearing 55 toward the rotor 3. The elastic member 8 is disposed between the outer race 57 and the bottom of the recess 72a. Examples of the elastic member 8 include a spring washer, a disc spring washer, a wave washer, or a rubber O-ring.

[0072] <case> The case 7 houses the stator 2, the rotor 3, a portion of the shaft 4, the first bearing 51, the second bearing 55, the shim 6, etc. The case 7 includes a peripheral wall portion 73, a first plate portion 71, and a second plate portion 72.

[0073] In this embodiment, the peripheral wall portion 73 and the second plate portion 72 are integrally formed. In this embodiment, the peripheral wall portion 73 and the first plate portion 71 are separate bodies. Unlike this embodiment, the peripheral wall portion 73 and the first plate portion 71 may be integrally formed, and the peripheral wall portion 73 and the second plate portion 72 may be separate bodies. Also, unlike this embodiment, the peripheral wall portion 73, the first plate portion 71, and the second plate portion 72 may be separate bodies. In this embodiment, the peripheral wall portion 73 and the first plate portion 71 are fixed to each other by fastening members 92. Similar to the fastening members 91, examples of the fastening members 92 include screws and bolts.

[0074] The peripheral wall portion 73 surrounds the outer peripheries of the stator 2 and the rotor 3. A hole is provided in the end surface of the peripheral wall portion 73. A fastening member 92 is provided in this hole.

[0075] The first plate portion 71 has a first plane 71f, a protruding portion 71a, a first through hole, a second through hole, and a third through hole. The first plane 71f is provided inside the case 7. The stator 2 and a shim 6 (described later) are disposed on the first plane 71f. The protruding portion 71a is provided between the stator 2 and the first bearing 51. The protruding portion 71a is connected to the first plane 71f. The protruding portion 71a protrudes from the first plane 71f. The shape of the protruding portion 71a is, for example, cylindrical. The inner circumferential surface of the protruding portion 71a contacts the outer circumferential surface of the outer race 53. The protruding portion 71a can be used to position the first bearing 51. The outer circumferential surface of the protruding portion 71a may or may not contact the inner circumferential surface of the yoke 22. A portion of the first shaft portion 41 is provided in the first through hole. A fastening member 91 is provided in the second through hole. The second through hole is provided at a position corresponding to the hole portion of the stator core 21. A fastening member 92 is provided in the third through hole. The second through hole is provided at a position corresponding to the hole portion of the peripheral wall portion 73.

[0076] The second plate portion 72 has a recess 72a in its center. A through hole 72h is provided at the bottom of the recess 72a. The fifth shaft portion 45 is provided within the through hole 72h. The inner diameter of the through hole 72h is larger than the outer diameter of the fifth shaft portion 45. Therefore, the shaft 4 rotates without contact between the inner circumferential surface of the through hole 72h and the fifth shaft portion 45. A second bearing 55 is disposed between the inner circumferential surface of the recess 72a and the fifth shaft portion 45.

[0077] <Sim> The shim 6 adjusts the length of the gap between the stator 2 and the rotor 3. In this embodiment, the shim 6 is disposed between the first plane 71f and the outer race 53, as shown in FIGS. 2 and 3. The shim 6 has a first surface and a second surface. The first surface is in contact with the first plane 71f. The second surface is in contact with the second end surface 53s without being in contact with the second end surface 52s. The shim 6 has an annular plate shape. The shim 6 may be formed of a single plate, or may be formed by stacking multiple shim pieces.

[0078] The gap length can be changed by changing the thickness Ts of the shim 6. When the shim 6 is disposed between the first flat surface 71f and the second end face 53s, the first end faces 52f, 53f of the first bearing 51 are positioned farther from the first flat surface 71f than when the shim 6 is not disposed between the first flat surface 71f and the second end face 53s. The contact between the first end face 52f and the first end face 42f moves the shaft 4 farther from the first flat surface 71f. The contact between the second end face 42s and the first face 31f moves the rotor 3 farther from the first flat surface 71f. Therefore, the gap length when the shim 6 is disposed between the first flat surface 71f and the second end face 53s is longer than the gap length when the shim 6 is not disposed between the first flat surface 71f and the second end face 53s. The thickness Ts of the shim 6 is the thickness at which the gap length becomes the design length G1.

[0079] [Process A] The parts prepared in step A are the parts of the motor 1 described above with reference to Fig. 1. In this embodiment, the parts include the stator 2, the rotor 3, the shaft 4, the first bearing 51, the second bearing 55, the shim 6, the case 7, the elastic member 8, the fastening member 91, and the fastening member 92.

[0080] (Process A1) The predicted gap length G0 calculated in step A1 refers to the gap length in a hypothetical motor 1Z shown in FIG. 4. The hypothetical motor 1Z is a hypothetical assembly using the above-described parts excluding the shim 6, and is not an actual assembly. The hypothetical motor 1Z includes a case 7, a stator 2, a rotor 3, a shaft 4, a first bearing 51, and a second bearing 55, but differs from the motor 1A manufactured by the motor manufacturing method of this embodiment in that it does not include the shim 6 shown in FIG. 1. In the hypothetical motor 1Z, the first bearing 51 is disposed on the first flat surface 71f of the case 7, where the shim 6 was disposed in the manufactured motor 1A. In the hypothetical motor 1Z, the first bearing 51, the shaft 4, and the rotor 3 are positioned closer to the first flat surface 71f than in the manufactured motor 1A by the thickness Ts of the shim 6. FIG. 5 shows an example in which the first end surface 52f and the first end surface 53f are not misaligned along the axial direction of the first bearing 51. 6 shows an example in which the first end surface 52f and the first end surface 53f are misaligned along the axial direction of the first bearing 51. As will be described in detail later, the first end surface 52f and the first end surface 53f may also be misaligned along the axial direction of the first bearing 51.

[0081] The predicted length G0 is calculated taking into consideration the actual dimensions of the stator 2. The actual dimensions of the stator 2 are the dimensions measured before assembly of the stator 2. Taking the actual dimensions into consideration includes cases where the actual dimensions themselves are taken into consideration, and cases where a calculated value obtained from the actual dimensions is taken into consideration. The calculated value obtained from the actual dimensions is, for example, the average value of the actual dimensions of each stator 2 calculated from multiple stators 2.

[0082] The number of measurements required to determine the average value may be less than the number of motors 1A manufactured. For example, assume that 1,000 motors 1A are manufactured. If one stator 2 is used in each motor 1A, the number of measurements required to determine the average value of the actual dimensions of that part may be less than 1,000. Even if two stators 2 are used, the number of measurements required to determine the average value of the actual dimensions of that part may be less than 1,000. More specifically, the average value may be determined from the actual dimensions of 50 or fewer stators 2. It is preferable to determine the average value for each lot of stators 2.

[0083] The actual dimension of the stator 2 is the actual dimension of the length L1 of the stator core 21 shown in Fig. 5. The actual dimension of the length L1 is determined from the actual dimension of the length between the first surface 22f of the yoke 22 and the end surface 23a of the teeth 23. The actual dimension of the length between the first surface 22f and the end surface 23a can be measured using a height gauge equipped with a class 0 surface plate.

[0084] The stator core 21 is placed on a surface plate with the end face 23a facing upward. A plurality of measurement points are selected on the end face 23a. The measurement points are set, for example, on a line drawn in a plan view of the stator core 21 so as to pass through the center of gravity of the end face 23a and the center of the yoke 22. It is preferable to select three or more measurement points on the line. In particular, it is preferable that the measurement points on the line include the center of gravity of the end face 23a, an edge of the end face 23a located toward the center of the yoke 22, and an edge of the end face 23a located away from the center of the yoke 22. The length between the first surface 22f and the end face 23a is the average length of the straight lines perpendicular to the surface plate that connect the surface plate to each measurement point.

[0085] The actual dimensions of the stator 2 may be determined from the actual dimension of the length between the contact point between the first flat surface 71f and the first surface 22f and the end surface 23a. The actual dimensions of the stator 2 may be determined from the actual dimension of the length between the first flat surface 71f and the end surface 23a. The actual dimension of the length between the first flat surface 71f and the end surface 23a is determined in the same manner as the actual dimension of the length between the first surface 22f and the end surface 23a. That is, the first plate portion 71 is placed on a surface plate, and the stator core 21 is placed on the first plate portion 71. The measurement points are the same as those used when measuring the actual dimension of the length between the first surface 22f and the end surface 23a.

[0086] The predicted length G0 is calculated by "actual dimensions of length L2 + length L3 + length L4 - length L5 - length L1" shown in FIG.

[0087] The length L2 is the length between the first contact point and the second contact point. The first contact point is the contact point between the first flat surface 71f and the first bearing 51. The second contact point is the contact point between the first bearing 51 and the first end face 42f. The length L2 is the height of the first bearing 51. Length L3 is the length between the second contact point and the third contact point. The third contact point is the contact point between the second end face 42s and the first face 31f. Length L3 is the length of the second shaft portion 42. In other words, length L3 is the length between the first end face 42f and the second end face 42s. The length L4 is the length between the third contact point and the bottom surface 32a. The length L4 is the depth of the recess 32. That is, the length L4 is the length between the first surface 31f and the bottom surface 32a. Length L5 is the length between bottom surface 32a and first end surface 35f. Length L5 is the thickness Tm of magnet 35. When magnet 35 and rotor body 31 are fixed with adhesive 38, length L5 is the sum of thickness Tm of magnet 35 and thickness Ta of adhesive 38.

[0088] All of these lengths are lengths along the axial direction of the shaft 4. Lengths L2 to L5 are all design dimensions and are known. The difference between the actual dimensions of lengths L2 to L5 and the design dimensions tends to be smaller than the difference between the actual dimension of length L1 and the design dimension. The difference between the actual dimension of length L1 and the design dimension tends to be larger, particularly when the stator core 21 is composed of a powder compact. Therefore, the predicted length G0 must take into account the actual dimension of length L1. Of course, it is preferable that the predicted length G0 take into account at least one actual dimension of lengths L2 to L5. The concept of each actual dimension of lengths L2 to L5 is the same as the concept of the actual dimension of the stator 2. Furthermore, the concept of each calculated value obtained from each actual dimension of lengths L2 to L5 is the same as the concept of the calculated value obtained from the actual dimension of the stator 2.

[0089] The actual dimension of length L2 may be either the actual height of the inner race 52 or the actual height of the outer race 53. The actual height of the outer race 53 is preferable because it is easier to measure than the actual height of the inner race 52. The actual height of the inner race 52 or the actual height of the outer race 53 is the average value of the heights at multiple measurement points. The measurement points are taken at equal intervals around the circumference of the inner race 52 or the outer race 53. The number of measurement points should be three or more.

[0090] The actual dimension of the length L3 is the average value of the lengths measured at a plurality of measurement points. The measurement points are set at equal intervals in the circumferential direction of the second shaft portion 42. The number of measurement points is three or more.

[0091] The actual dimension of length L4 is the average value of the depths at multiple measurement points. The measurement points are taken at equal intervals on the circumference of three concentric circles. The three circumferences refer to the circumference of the inner peripheral edge of recess 32, the circumference of the outer peripheral edge of recess 32, and the circumference of a midpoint between the inner peripheral edge and the outer peripheral edge of recess 32, when viewed from above. The number of measurement points on each circumference is three or more. A measurement point on the circumference of the inner peripheral edge, a measurement point on the circumference of the outer peripheral edge, and a measurement point on the circumference of the midpoint are located on a straight line along the radial direction of rotor 3. The depth of each measurement point is the length along the axial direction of rotor 3 between each measurement point and first surface 31f of rotor body 31.

[0092] When there are multiple magnets 35, the actual length L5 is the average value of the thicknesses Tm of the multiple magnets 35. Each thickness Tm may be the thickness at one measurement point or the average value of the thicknesses Tm at multiple measurement points. One measurement point is the center of gravity of the first end face 35f when viewed from above. The multiple measurement points are set on a line drawn from the center of gravity of the first end face 35f to the center of the rotor 3 when viewed from above. Preferably, three or more measurement points are set on the line. In particular, the multiple measurement points preferably include the center of gravity of the first end face 35f, an edge of the first end face 35f located closer to the center of the rotor 3, and an edge of the first end face 35f located farther from the center of the rotor 3. The thickness Tm of each magnet 35 is the average value of the length along the axial direction of the rotor 3 at each measurement point.

[0093] When there is one magnet 35 and the magnet 35 is annular, the actual dimension of the length L5 is the average value of the thicknesses Tm at multiple measurement points. The measurement points are taken at equal intervals on the circumference of three concentric circles. The three circumferences refer to the circumference of the inner periphery of the first end face 35f, the circumference of the outer periphery of the first end face 35f, and the circumference at the midpoint between the inner and outer peripheries of the first end face 35f, when viewed from above. The number of measurement points on each circumference shall be three or more. The measurement point on the circumference of the inner periphery, the measurement point on the circumference of the outer periphery, and the measurement point on the midpoint are located on a straight line along the radial direction of the rotor 3. The thickness at each measurement point is the length along the axial direction of the rotor 3 at that measurement point.

[0094] The actual dimension of length L5 is the actual dimension when the rotor body 31 and magnet 35 are fixed together when adhesive 38 is provided. That is, the actual dimension of length L5 is the average length along the axial direction of the rotor 3 between the measurement point of the thickness Tm of magnet 35 and the bottom surface 32a of recess 32.

[0095] The predicted length G0 is preferably calculated by further taking into consideration the amount of deviation g of the first bearing 51 shown in Fig. 6. That is, the length L2 is preferably calculated by further taking into consideration the amount of deviation g. The amount of deviation g is the length along the axial direction of the first bearing 51 between the first end face 53f and the first end face 52f.

[0096] The amount of deviation g is determined by taking into consideration the load acting on the inner race 52 due to the weight of the shaft 4 and rotor 3, and the load acting on the inner race 52 due to the attractive force of the magnet 35 toward the stator 2. The amount of deviation g is also determined by taking into consideration at least one of the load acting on the inner race 52 due to the weight of the second bearing 55, and the load acting on the inner race 52 due to the pressing force of the elastic member 8 pressing the second bearing 55 toward the first bearing 51.

[0097] The inner race 52 is primarily subjected to loads due to the weight of the shaft 4 and rotor 3 and the attractive force of the magnet 35 toward the stator 2. The inner race 52 is also subjected to at least one of the following loads: the weight of the second bearing 55 and the pressing force of the elastic member 8 pressing the second bearing 55 toward the first bearing 51. Depending on the magnitude of the load, the first end face 52f may be misaligned with respect to the first end face 53f. The misalignment of the first end face 52f is particularly influenced by the attractive force of the magnet 35. That is, the stronger the magnetic force of the magnet 35, the greater the misalignment of the first end face 52f. The difference between the predicted gap length G0 shown in FIG. 6 and the designed length G1 shown in FIG. 3 increases by the amount of misalignment g. Therefore, it is preferable to consider the misalignment g.

[0098] The amount of deviation g can be obtained from a graph such as that shown in Fig. 7. The load (N) on the vertical axis of Fig. 7 represents the load on the inner race 52 of the first bearing 51. The amount of deviation (mm) on the horizontal axis of Fig. 7 represents the amount of deviation g of the first end face 52f of the inner race 52 relative to the first end face 53f of the outer race 53 of the first bearing 51. The graph of Fig. 7 should be prepared in advance. Specifically, the graph of Fig. 7 can be obtained by applying a load to the inner race 52 in the axial direction of the first bearing 51 while displacing the load.

[0099] The predicted length G0 is calculated by "(length L2 - deviation amount g) + length L3 + length L4 - length L5 - actual length L1." Even when deviation amount g is taken into consideration, it is preferable that at least one of lengths L2 to L5 is the actual length.

[0100] (Process A2) In step A2, the thickness Ts of the shim 6 is determined before the process of assembling the parts, i.e., before manufacturing the above-described motor 1A, from the difference between the design length G1 of the gap shown in Fig. 2 and the predicted length G0 of the gap shown in Fig. 5. Alternatively, the thickness Ts of the shim 6 is determined from the difference between the design length G1 of the gap shown in Fig. 3 and the predicted length G0 of the gap shown in Fig. 6.

[0101] [Process B] In process B for assembling the parts, the stator 2, rotor 3, shaft 4, first bearing 51, and shim 6 are arranged in predetermined positions within the case 7. As long as the motor 1A as shown in FIG. 1 can be manufactured by process B, the order in which the parts are assembled is not particularly limited. One example of process B is to perform the following processes B1 to B5 in order.

[0102] (An example of the order in which parts are assembled) In step B1, the shim 6 and the stator 2 are arranged on the first flat surface 71f of the first plate portion 71. As described above, the thickness Ts of the shim 6 is equal to the difference between the design length G1 and the predicted length G0 of the gap. When the predicted length G0 is shorter than the design length G1 as in this embodiment, the shim 6 is arranged on the first flat surface 71f corresponding to the lower side of the first bearing 51 in step B1. In step B2, the first bearing 51 is placed on the shim 6. In step B3, the first shaft portion 41 of the shaft 4 is placed in the first bearing 51. A rotor assembly in which the rotor 3 and shaft 4 are combined is prepared in advance. In step B3, the first shaft portion 41 of the rotor assembly is placed in the first bearing 51. In this case, step B4 is proceeded to without step B31. If the rotor 3 and shaft 4 are prepared without being combined without preparing a rotor assembly, step B31 is proceeded to before step B4. In step B31, the rotor 3 is fitted onto the shaft 4 in a state in which the first shaft portion 41 is placed in the first bearing 51. In step B4, the second bearing 55 is fitted onto the fourth shaft portion 44 of the shaft 4. In step B5, the through hole 72h of the second plate portion 72 is fitted onto the fifth shaft portion 45 of the shaft 4, and the end face of the peripheral wall portion 73 is butted against the first plate portion 71. Then, the first plate portion 71 and the peripheral wall portion 73 are fixed together by the fastening member 92. The fastening member 92 is provided in the third through hole of the first plate portion 71 and the hole portion of the peripheral wall portion 73.

[0103] The motor 1A shown in Fig. 1 is manufactured by assembling the parts in this order. The gap length of the manufactured motor 1A is the designed length G1, as shown in Fig. 2 or 3. The designed length G1 shown in Fig. 2 or 3 is longer than the predicted length G0 of the hypothetical motor 1Z shown in Fig. 5 or 6 by the thickness Ts of the shim 6 shown in Fig. 2 or 3.

[0104] [Action and effect] The motor manufacturing method of this embodiment can calculate the predicted gap length G0, and therefore the difference between the predicted gap length G0 and the design length G1, by taking into account the actual dimensions of a specific part before assembling the parts. The predicted gap length G0 calculated by taking into account the actual dimensions is more accurate than the predicted gap length calculated from the design dimensions and dimensional tolerances of the part. In other words, the difference between the predicted gap length G0 calculated by taking into account the actual dimensions and the design length G1 is more accurate than the difference between the predicted gap length calculated from the design dimensions and dimensional tolerances and the design length of the gap.

[0105] A load acting on first end face 52f of inner race 52 of first bearing 51 may cause first end face 52f of inner race 52 to shift relative to first end face 53f of outer race 53. Even in this case, the motor manufacturing method of this embodiment can determine predicted length G0 taking the amount of shift g into consideration, making it possible to determine an accurate predicted length G0, and therefore an accurate difference between predicted length G0 and designed length G1.

[0106] The motor manufacturing method of this embodiment can assemble parts including a shim 6 having the exact same thickness as the gap. Therefore, the motor manufacturing method of this embodiment can set the gap length to the designed length G1 by assembling the parts only once. Therefore, the motor manufacturing method of this embodiment is excellent in manufacturability of the motor 1A, which has excellent assembly precision.

[0107] The motor manufacturing method of this embodiment is excellent in the manufacturability of multiple motors 1A with excellent assembly precision, even when the process B of assembling parts is repeated. Therefore, the motor manufacturing method of this embodiment can manufacture multiple motors 1A with little variation in performance. In particular, by determining the predicted length based on the average value of the actual dimensions, which is less than the number of motors to be manufactured, manufacturability of the motors 1A is more easily improved than when the predicted length is determined based on the actual dimensions of a number equal to the number of motors to be manufactured.

[0108] Second Embodiment [Motor manufacturing method] A method for manufacturing a motor according to the second embodiment will be described with reference to FIGS. 8 to 14. FIG. 8 is a cross-sectional view of a motor 1A manufactured by the manufacturing method for a motor according to this embodiment, taken along a plane parallel to the axial direction of the shaft 4. The motor 1A in FIG. 8 is assembled using all of the parts. FIG. 8 illustrates an example of a single-stator, single-rotor axial gap motor as the manufactured motor 1A. FIG. 12 shows a cross-sectional view of a hypothetical motor 1Z taken along a plane parallel to the axial direction of the shaft 4.

[0109] The motor manufacturing method of this embodiment differs from that of embodiment 1 in the location where shim 6 is placed in step B. The following description will focus on the differences from embodiment 1. Description of the same configuration as embodiment 1 may be omitted.

[0110] First, the manufactured motor 1A will be described. Then, a method for manufacturing the motor 1A will be described. The motor manufacturing method of this embodiment takes as an example a case where the predicted length G0 exceeds the designed length G1, as shown in FIGS. 9 and 13 or 10 and 14.

[0111] <Sim> In this embodiment, the shim 6 is disposed between the first flat surface 71f and the first surface 22f, as shown in Figures 8 to 10. The first surface of the shim 6 is in contact with the first flat surface 71f. The second surface of the shim 6 is in contact with the first surface 22f. As shown in Figure 11, the shape of the shim 6 is annular. The shim 6 in this embodiment is formed from a single plate.

[0112] 8 to 10, when the shim 6 is disposed between the first flat surface 71f and the first surface 22f, the position of the end surface 23a is closer to the first end surface 35f than when the shim 6 is not disposed between the first flat surface 71f and the first surface 22f. Therefore, the length of the gap when the shim 6 is disposed between the first flat surface 71f and the first surface 22f is shorter than the length of the gap when the shim 6 is not disposed between the first flat surface 71f and the first surface 22f. The thickness Ts of the shim 6 is the thickness at which the length of the gap becomes the designed length G1.

[0113] 11, the shim 6 has a plurality of through holes 61. The through holes 61 are holes into which fastening members 91 are fitted. The through holes 61 are provided at locations corresponding to the holes in the stator core 21.

[0114] The area of ​​the first surface and the second surface of the shim 6 is preferably 95% or more and 100% or less of the area of ​​the first surface 22f of the yoke 22. This is because the shim 6 facilitates heat dissipation from the stator 2. The area of ​​the first surface and the second surface of the shim 6 is further preferably more than 95% and less than 100% of the area of ​​the first surface 22f, and particularly preferably 96% or more and 99% or less of the area of ​​the first surface 22f.

[0115] (Process A1 / Process A2) The method for determining the predicted length G0 in step A1 and the method for determining the thickness Ts of the shim 6 in step A2 are the same as those in the first embodiment.

[0116] [Process B] In step B1, the shim 6 and the first bearing 51 are arranged on the first flat surface 71f of the first plate portion 71. As described above, the thickness Ts of the shim 6 is equal to the difference between the design length G1 and the predicted length G0 of the gap. When the predicted length G0 is longer than the design length G1, as in this embodiment, the shim 6 is arranged on the first flat surface 71f corresponding to the lower side of the stator 2 in step B1. In step B2, the stator 2 is placed on the shim 6. Steps B3 and after are the same as those in the first embodiment.

[0117] [Action and effect] The method of manufacturing the motor of this embodiment, like the first embodiment, is excellent in the manufacturability of the motor 1A, which has excellent assembly precision.

[0118] Third Embodiment [Motor manufacturing method] A method for manufacturing a motor according to the third embodiment will be described with reference to Fig. 15. Fig. 15 is a cross-sectional view of a motor 1A manufactured by the manufacturing method according to the present embodiment, cut along a plane parallel to the axial direction of the shaft 4.

[0119] The method for manufacturing a motor of this embodiment differs from the method for manufacturing a motor of embodiment 2 in that at least one of the stator core 21 and the first plate portion 71 to be prepared has a positioning portion for the shim 6. The following description will focus on the differences from embodiment 2. Description of configurations that are the same as those in embodiment 2 may be omitted. These points also apply to embodiment 4 and embodiment 6, which will be described later.

[0120] In this embodiment, both the stator core 21 and the first plate portion 71 have a positioning portion for the shim 6. A recess 221 is provided on the first surface 22f of the stator core 21 as a positioning portion. A recess 711 is provided on the first flat surface 71f of the first plate portion 71 as a positioning portion. The recess 221 and the recess 711 have the same shape. The recess 221 and the recess 711 are annular in shape corresponding to the shape of the shim 6. The total depth of the recess 221 and the recess 711 exceeds the thickness of the shim 6. The depth of the recess 221 and the recess 711 may be the same as or different from each other.

[0121] The area of ​​the first surface of the shim 6 is less than 100% of the area of ​​the first surface 22f of the yoke 22. The lower limit of the area of ​​the first surface of the shim 6 is the same as in the second embodiment.

[0122] (Process A1 / Process A2) The method for determining the predicted length G0 in step A1 is the same as in embodiment 1. In step A2, the thickness of the shim 6 is determined by "predicted length G0 - designed length G1 + actual dimension of the depth of the recess 221 + depth of the recess 711."

[0123] The actual depth of the recess 221 is the actual length between the first surface 22f and the bottom surface of the recess 221. The depth of the recess 221 is the length along the axial direction of the shaft 4. The actual depth of the recess 221 is the average value of the depths at multiple measurement points. The method of selecting the measurement points is the same as the method of selecting the measurement points in determining the actual length L4 described above.

[0124] The depth of the recess 711 is the length between the first plane 71f and the bottom surface of the recess 711. The depth of the recess 711 is a design dimension and is known. The depth of the recess 711 is preferably an actual dimension. The actual dimension of the depth of the recess 711 is the average value of the depths at multiple measurement points. The method of selecting the measurement points is the same as the method of selecting the measurement points when determining the actual dimension of the length L4.

[0125] [Process B] In step B1, the shim 6 is placed in the recess 711. In step B1, the first bearing 51 is placed in the same position as in the second embodiment. In step B2, the stator 2 is positioned so that the recess 221 fits into the shim 6. A gap is formed between the first surface 22f and the first flat surface 71f. The size of this gap is the difference between the predicted length G0 and the designed length G1. Steps B3 and after are the same as those in the second embodiment.

[0126] [Action and effect] The motor manufacturing method of this embodiment makes it easy to position the shim 6 relative to the first plate portion 71. Furthermore, the motor manufacturing method of this embodiment makes it easy to position the stator 2 relative to the shim 6. Therefore, the motor manufacturing method of this embodiment makes it easy to assemble parts.

[0127] Fourth Embodiment [Motor manufacturing method] A method for manufacturing the motor of the fourth embodiment will be described with reference to Fig. 16. The method for manufacturing the motor of this embodiment differs from the method for manufacturing the motor of the second embodiment in the following requirements (a) and (b). (a) The stator core 21 to be prepared has a plurality of stator core pieces 210. (b) The shim 6 to be prepared has a plurality of shim pieces 60.

[0128] Stator core pieces Each stator core lamination 210 is composed of one yoke piece 220 and at least one tooth. The number of stator core laminations 210 can be selected as appropriate. The number of stator core laminations 210 in this embodiment is six. That is, the number of yoke laminations 220 in this embodiment is six. The shape of the yoke laminations 220 is fan-shaped. The number of teeth connected to each yoke piece 220 may be one or more. In this embodiment, the number of teeth connected to each yoke piece 220 is two. In this embodiment, the actual length of each stator core lamination 210 is substantially the same. The actual length of each stator core lamination 210 is the actual length between the first surface 22f of the yoke piece 220 and the end face of the tooth. The method for determining the actual length of each stator core lamination 210 is the same as the method for determining the actual length L1 described in embodiment 1.

[0129] <Sim> The shim 6 is composed of a plurality of shim pieces 60 divided in the circumferential direction. The number of shim pieces 60 is the same as the number of stator core pieces 210. The shape of the shim pieces 60 is the same as the shape of the yoke pieces 220. The shape of the shim pieces 60 in this embodiment is a fan plate shape.

[0130] (Process A1) In step A1, when the actual dimensions of the above-mentioned length of each stator core lamination 210 are substantially the same as in the present embodiment, a predicted length G0 corresponding to one stator core lamination 210 may be calculated. Alternatively, in step A1, even when the actual dimensions of the above-mentioned length of each stator core lamination 210 are substantially the same as in the present embodiment, a predicted length G0 corresponding to each stator core lamination 210 may be calculated. That is, the same number of predicted lengths G0 as the number of stator core laminations 210 are calculated. The method for calculating the predicted length G0 is the same as the method for calculating the predicted length G0 described in embodiment 1.

[0131] (Process A2) In step A2, the thickness of all shim pieces 60 is determined from the difference between one predicted length G0 and the design length G1. Alternatively, the thickness of each shim piece 60 may be determined from the difference between each predicted length G0 and the design length G1. The method for determining the thickness of each shim piece 60 is the same as the method for determining the thickness of the shim 6 described in embodiment 1.

[0132] [Action and effect] The motor manufacturing method of this embodiment is excellent in the manufacturability of motors with excellent assembly precision, even when the stator core 21 includes a plurality of stator core pieces 210.

[0133] Fifth Embodiment A method for manufacturing a motor according to the fifth embodiment will be described with reference to Fig. 17. Fig. 17 is a cross-sectional view of a motor 1A manufactured by the method for manufacturing a motor according to the present embodiment, taken along a plane parallel to the axial direction of the shaft 4.

[0134] The manufacturing method of the motor of this embodiment differs from the manufacturing method of the motor of embodiment 4 in the following requirements (a) and (b). (a) Of the multiple stator core laminations 210 to be prepared, the actual dimension of the length L1 of at least one stator core lamination 210 is different from the actual dimension of the length L1 of the other stator core laminations 210. (b) Of the multiple shim pieces 60 prepared, at least one shim piece 60 has a thickness different from the other shim pieces 60 . The following description will focus on the differences from the fourth embodiment, and the description of the same configuration as the fourth embodiment may be omitted.

[0135] (Process A1) In step A1, when the actual dimension of the length L1 of at least one stator core lamination 210 differs from the actual dimension of the length L1 of the other stator core laminations 210, as in this embodiment, a predicted length G0 corresponding to the stator core laminations 210 with different lengths is determined. For example, consider a case where, of six stator core laminations 210, three stator core laminations 210 have a length L1 of A (mm), two stator core laminations 210 have a length L1 of B (mm), and one stator core lamination 210 has a length L1 of C (mm), where A ≠ B ≠ C. In this case, three predicted lengths G0 are determined. The first predicted length G0 is the predicted length corresponding to the stator core lamination 210 with a length L1 of A (mm). The second predicted length G0 is the predicted length corresponding to the stator core lamination 210 with a length L1 of B (mm). The third predicted length G0 is the predicted length corresponding to the stator core lamination 210 with a length L1 of C (mm). Of course, in step A1, the predicted length G0 corresponding to each stator core lamination 210 may be obtained. That is, the same number of predicted lengths G0 as the number of stator core laminations 210 are obtained. The method for obtaining each predicted length G0 is the same as the method for obtaining the predicted length G0 described in the first embodiment.

[0136] (Process A2) In step A2, the thickness of each shim piece 60 is determined from the difference between the three predicted lengths G0 and the design length G1. The method for determining the thickness of each shim piece 60 is the same as the method for determining the thickness of the shim 6 described in the first embodiment.

[0137] [Action and effect] The motor manufacturing method of this embodiment is excellent in manufacturability of the motor 1A, which has excellent assembly precision, even when the lengths L1 of the stator core pieces 210 are different.

[0138] Sixth Embodiment [Motor manufacturing method] A method for manufacturing a motor according to the sixth embodiment will be described with reference to Fig. 18. Fig. 18 is a cross-sectional view of a motor 1A manufactured by the manufacturing method according to the sixth embodiment, taken along a plane parallel to the axial direction of the shaft 4.

[0139] The motor manufacturing method of this embodiment differs from the motor manufacturing method of embodiment 2 in that a double stator / single rotor type axial gap motor is manufactured. A double stator / single rotor type is a motor with two stators 2 and one rotor 3. In a double stator / single rotor type, one rotor 3 is assembled so that it is sandwiched between two stators 2 in the axial direction of a shaft 4.

[0140] <Rotor> The rotor body 31 is an annular flat plate member. The rotor body 31 has one first through hole and at least one second through hole. The first through hole is provided in the center. The third shaft portion 43 of the shaft 4 is provided in the first through hole. The second through hole is provided on the outer periphery side of the first through hole. A magnet 35 is provided in the second through hole. The number of second through holes is the same as the number of magnets 35.

[0141] As shown in FIG. 18 , in this embodiment, the thickness of the rotor body 31 and the thickness of the magnet 35 are the same. That is, the first surface of the rotor body 31 and the first end surface of the magnet 35 are flush with each other. Furthermore, the second surface of the rotor body 31 and the second end surface of the magnet 35 are flush with each other. The first surface of the rotor body 31 and the first end surface of the magnet 35 are surfaces provided on one stator 2 side. The second surface of the rotor body 31 and the second end surface of the magnet 35 are surfaces provided on the other stator 2 side. Here, the stator 2 shown on the lower side of FIG. 18 is one stator 2. Furthermore, the stator 2 shown on the upper side of FIG. 18 is the other stator 2. Although not shown, the thickness of the rotor body 31 and the magnet 35 do not have to be the same.

[0142] <case> The case 7 of this embodiment includes a pair of first plate portions 71 and a peripheral wall portion 73. The pair of first plate portions 71 and the peripheral wall portion 73 are configured as separate bodies. One of the first plate portions 71 and the peripheral wall portion 73 is fixed to each other by a fastening member 92. The other of the first plate portions 71 and the peripheral wall portion 73 is fixed to each other by a fastening member 92.

[0143] (Process A1 / Process A2) The method for calculating one predicted length is the same as in embodiment 1. The method for calculating the other predicted length is calculated by "the height of the other first bearing 51 + the length of the third shaft portion 43 - the thickness of the magnet 35 - the actual dimension of the length of the stator core 21." In the lower part of FIG. 18, the length of the gap when the shim 6 is not placed is taken as one predicted length. In the upper part of FIG. 18, the length of the gap when the shim 6 is not placed is taken as the other predicted length. The method for calculating the thickness of one shim 6 and the method for calculating the thickness of the other shim 6 are the same as in embodiment 1.

[0144] The length of the third shank 43 is the length between the end face 43a and the second end face 42s. The length of the third shank 43 is the length along the axial direction of the third shank 43. The length of the third shank 43 is a design dimension and is known. The length of the third shank 43 is preferably the actual dimension. The actual dimension of the length of the third shank 43 is the average value of the lengths at multiple measurement points. The measurement points are taken at equal intervals around the circumference of the third shank 43. The number of measurement points is three or more. The length at each measurement point is the length along the axial direction of the third shank 43 at that measurement point.

[0145] [Action and effect] The method of manufacturing the motor of this embodiment, like the first embodiment, is excellent in the manufacturability of the motor 1A, which has excellent assembly precision.

[0146] The present invention is not limited to these examples, but is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0147] 1A motor, 1Z virtual motor 2 stator 21 stator core, 210 stator core piece 22 yoke, 220 yoke pieces, 22f first surface, 221 recess, 22s second surface 23 teeth, 23a end face 25 coils 3 rotors 31 Rotor body 31f first side, 31s second side, 32 recess, 32a bottom side 35 magnet, 35f first end surface, 38 adhesive 4 shafts 41 First shaft part 42 Second shaft part, 42f first end surface, 42s second end surface 43 Third shaft section, 43a end face 44 Fourth shaft part, 45 Fifth shaft part 51 First Bearing 52 inner race, 52f first end face, 52s second end face 53 outer race, 53f first end face, 53s second end face 54 balls 55 Second bearing 56 Inner race, 57 Outer race 6 shim, 60 shim piece, 61 through hole 7 Cases 71 First plate section 71f first plane, 711 recess, 71a protrusion 72 Second plate section 72a recess, 72h through hole, 73 peripheral wall 8 Elastic member 91, 92 Fastening members L1, L2, L3, L4, L5 lengths G0 predicted length, G1 design length g deviation amount Ts, Tm, Ta thickness

Claims

1. preparing parts for an axial gap type motor; and assembling the parts. The parts are: A rotor, A stator including a stator core formed of a powder compact; A shaft that is a rotation axis of the rotor; A bearing that rotatably supports the shaft; a case having a first plane on which the stator and the bearing are mounted; a shim disposed between the first plane and the bearing or between the first plane and the stator; The step of preparing the part includes: determining a predicted length of a gap between the rotor and the stator taking into account the actual dimensions of the stator core; determining a thickness of the shim based on a difference between a design length of the gap and the predicted length. A method for manufacturing a motor.

2. If the predicted length is greater than the design length, The method for manufacturing a motor according to claim 1 , wherein in the step of assembling the parts, the shim is disposed between the first plane and the stator.

3. If the predicted length is less than the design length, The method for manufacturing a motor according to claim 1 , wherein in the step of assembling the parts, the shim is disposed between the first plane and the bearing.

4. The method for manufacturing a motor according to claim 1 , wherein the step of determining the predicted length further determines the predicted length by taking into account actual dimensions of the rotor, the shaft, and the bearings.

5. The rotor is A rotor body having a circular plate shape; At least one magnet fixed to the rotor body, the bearing is a radial or angular bearing having an inner race and an outer race, Each of the inner race and the outer race has a first end surface facing the rotor body, The step of determining the predicted length further includes determining the predicted length taking into consideration a deviation between the first end surface of the outer race and the first end surface of the inner race, 5. The method for manufacturing a motor according to claim 1, wherein the amount of deviation is determined by taking into consideration a load acting on the inner race due to the weight of the shaft and the rotor, and a load acting on the inner race due to an attractive force of the magnet to the stator.

6. The stator includes: A circular plate-shaped yoke; a plurality of columnar teeth arranged at intervals in a circumferential direction of the yoke; the yoke has a first surface in contact with the first plane, The teeth have end surfaces facing the rotor, The method for manufacturing a motor according to claim 1 , wherein the step of determining the predicted length determines the predicted length taking into account an actual dimension between the first surface of the yoke and the end surfaces of the teeth.

7. The method for manufacturing a motor according to claim 1 , wherein the part includes a fastening member that fixes the first plane and the stator.

8. The rotor is A rotor body having a circular plate shape; At least one magnet fixed to the rotor body, the rotor body has a first surface facing the magnet; The magnet has a first end surface facing the stator, 8. A method for manufacturing a motor according to claim 1, wherein the step of calculating the predicted length calculates the predicted length by taking into account an actual dimension of a length between the first surface of the rotor body and the first end surface of the magnet in the rotor in which the rotor body and the magnet are fixed.

9. The number of the magnets is one. The method for manufacturing a motor according to claim 8 , wherein the magnet has a circular ring shape.

10. The method for manufacturing a motor according to claim 1 , wherein the step of assembling the parts comprises press-fitting the shaft into the rotor.

11. Repeating the process of assembling the parts; 11. The method for manufacturing a motor according to claim 1, wherein the step of calculating the predicted length calculates the predicted length by taking into account average values ​​of actual dimensions of the stator, the rotor, the shaft, and the bearings, the number of which is smaller than the number of motors to be manufactured.

12. The method for manufacturing a motor according to claim 1 , wherein the number of the stators and the number of the rotors are one each.

13. The method for manufacturing a motor according to claim 1 , wherein the number of the stators is two and the number of the rotors is one.

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