Brushless motor

Abstract

To provide a brushless motor capable of reducing press-fitting load to a stator case and improving assembly accuracy.SOLUTION: A case 31 includes a total of six first to sixth flat portions 32A to 32F arranged in the circumferential direction of the case 31 and a total of six first to sixth circular arc portions 32a to 32f that connect adjacent flat portions to each other. The inner circumferential surfaces CF of the first to sixth circular arc portions 32a to 32f are all formed in a circular arc shape with a radius R1 centered on the center AC of the case 31 when viewed in the axial direction of a shaft 44. Since a stator 35 is supported only by the inner peripheral surfaces CF (six in total), the press-fitting load of the stator 35 to the case 31 can be reduced, and the assembly accuracy can be improved.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an inner rotor type brushless motor. [Background technology]

[0002] Conventionally, brushless motors for vehicles such as automobiles include those used in sunroof devices and power window devices. These brushless motors are required to be installed in narrow spaces such as the ceiling or inside the doors of the vehicle, and therefore are desired to be thin. Such brushless motors are described, for example, in Patent Document 1.

[0003] The brushless motor described in Patent Document 1 is an inner rotor type brushless motor that includes a motor case that is hexagonal when viewed in the axial direction of the rotating shaft. The motor case houses a stator core that is also hexagonal when viewed in the axial direction of the rotating shaft, just like the motor case. This allows the entire brushless motor to fit within the width of two opposing faces of the motor case, with the center of the motor case as the center. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-127146 Summary of the Invention [Problem to be solved by the invention]

[0005] The brushless motor described in the aforementioned Patent Document 1 employs a structure in which a hexagonal stator core (stator) is tightly housed inside a hexagonal motor case (case). This poses a problem of a large press-fit load when the stator core is press-fitted into the motor case. To reduce the press-fit load, a small gap may be created between the two and filled with an epoxy resin adhesive or the like. However, this can result in misalignment of the centers of the stator core and the motor case, reducing the assembly precision of the brushless motor and ultimately resulting in variations in the rotational resistance of the brushless motor from one product to another.

[0006] An object of the present invention is to provide a brushless motor that can reduce the press-fit load of the stator into the case and improve assembly precision. [Means for solving the problem]

[0007] In one aspect of the present invention, there is provided a brushless motor including a stator having a hollow portion, a case that houses the stator, and a shaft that is rotatably housed in the hollow portion and rotatably supported by the case, wherein the case includes a plurality of rotors arranged in a circumferential direction of the case. 6 in total and connecting the adjacent flat portions to each other. 6 in total a connection part A total of 6 an inner circumferential surface of the connecting portion Each of is formed in an arc shape centered on the center of the case when viewed in the axial direction of the shaft, and the stator is At least three Supported only by the inner circumferential surface When viewed in the axial direction of the shaft, the center of the case is located within an area surrounded by straight lines connecting at least three supported portions of the stator supported on the inner peripheral surface. are. [Effects of the Invention]

[0008] According to the present invention, the case has a plurality of flat portions arranged circumferentially of the case and a plurality of connecting portions that connect adjacent flat portions to each other, and the inner surface of the connecting portion is formed in an arc shape centered on the center of the case when viewed in the axial direction of the shaft, and the stator is supported only by the inner surface, so that the press-fit load can be reduced and assembly accuracy can be improved. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing a sunroof device installed on the roof of a vehicle. [Figure 2] FIG. 2 is a perspective view showing the output gear side of the sunroof motor. [Figure 3] FIG. 2 is a perspective view showing the cover member side of the sunroof motor. [Figure 4] FIG. 2 is a cross-sectional view of the sunroof motor taken along the axial direction of the shaft. [Figure 5] FIG. 5 is a cross-sectional view taken along line AA in FIG. [Figure 6] FIG. 6 is an enlarged view of a portion B circled by a dashed line in FIG. 5. [Figure 7] FIG. 5 is a cross-sectional view taken along line CC in FIG. [Figure 8] 10 is an exploded perspective view illustrating a procedure for assembling the stator to the case. FIG. [Figure 9] FIG. 5 is a view of the stator alone as seen from the direction of arrow D in FIG. 4. [Figure 10] FIG. 7 is a cross-sectional view showing the second embodiment, corresponding to FIG. 6. [Figure 11] FIG. 7 is a cross-sectional view showing a third embodiment, corresponding to FIG. 6. [Figure 12] FIG. 10 is a diagram illustrating support locations of the stator in Comparative Example 1. [Figure 13] FIG. 10 is a diagram illustrating support locations of the stator in Comparative Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Embodiment 1] Hereinafter, the first embodiment of the present invention will be described in detail with reference to the drawings.

[0011] Figure 1 is a schematic diagram showing a sunroof device installed on the roof of a vehicle, Figure 2 is an oblique view showing the output gear side of a sunroof motor, Figure 3 is an oblique view showing the cover member side of a sunroof motor, Figure 4 is a cross-sectional view of the sunroof motor along the axial direction of the shaft, Figure 5 is a cross-sectional view along line AA in Figure 4, Figure 6 is an enlarged view of the dotted circle B in Figure 5, Figure 7 is a cross-sectional view along line CC in Figure 4, Figure 8 is an exploded oblique view explaining the procedure for assembling the stator into the case, and Figure 9 is a view of the stator alone as seen from the direction of arrow D in Figure 4.

[0012] [Sunroof device overview] As shown in FIG. 1, a sunroof device 10 includes a roof panel 11. The roof panel 11 opens and closes an opening 14 formed in a roof 13 of a vehicle 12. A pair of shoes 15a, 15b is fixed to each of both sides of the roof panel 11 in the vehicle width direction (top and bottom sides in FIG. 1). Furthermore, a guide rail 16 extending in the front-to-rear direction of the vehicle 12 (left-to-right direction in FIG. 1) is fixed to each of both sides of the opening 14 in the roof 13 in the vehicle width direction. The pair of shoes 15a, 15b are guided by the corresponding pair of guide rails 16, causing the roof panel 11 to move in the front-to-rear direction of the vehicle 12.

[0013] One end of geared drive cables 17a, 17b is connected to each of the shoes 15b arranged on the rear side (right side in FIG. 1) of the vehicle 12. The other ends of the drive cables 17a, 17b are routed forward of the opening 14 of the vehicle 12 (left side in FIG. 1).

[0014] A sunroof motor 20 is provided inside the roof 13, further forward of the opening 14 on the vehicle 12 than the windshield FG. The other ends of the pair of drive cables 17a, 17b are engaged with an output gear 64 provided on the sunroof motor 20. When the sunroof motor 20 is driven, the pair of drive cables 17a, 17b move in opposite directions along their length. As a result, the roof panel 11 is pushed and pulled by the pair of drive cables 17a, 17b via the pair of shoes 15b, opening and closing the opening 14.

[0015] [Sunroof motor overview] 2 to 4, the sunroof motor 20 includes an electric motor unit 30 and a speed reduction mechanism unit 50. The electric motor unit 30 and the speed reduction mechanism unit 50 are firmly connected to each other by a first fastening screw S1 and a second fastening screw S2, and are integrated (unitized).

[0016] [Electric motor] The electric motor unit 30 is a motor without brushes, i.e., a brushless motor, and corresponds to the brushless motor of the present invention. The electric motor unit 30 has a case 31 formed into a cylindrical shape with a bottom by deep drawing or the like of a magnetic material such as a steel plate. The case 31 forms the outer shell of the electric motor unit 30 and has a side wall portion 32 formed in a hexagonal shape when viewed in the axial direction of the case 31. One axial side of the side wall portion 32 (the right side in Figures 2 to 4) is closed by a cylindrical bottom wall portion 33.

[0017] [Stator unit] As shown in Figures 4 and 5, a stator unit 34 is housed inside the case 31. The stator unit 34 has a stator 35 formed by laminating multiple thin steel plates (magnetic materials). The stator 35 is fixed to the inside of the case 31 and is equipped with a total of six teeth 36. Three-phase coils 38 consisting of U-phase, V-phase, and W-phase are wound around these teeth 36 with insulators (insulating members) 37 interposed therebetween. A hollow portion HP is formed radially inside the stator 35, i.e., on the tip side of the total of six teeth 36. A rotor unit 40 is housed in the hollow portion HP so as to be rotatable without contacting the teeth 36.

[0018] [Rotor unit] A rotor unit 40 is rotatably provided radially inside the stator 35 via a predetermined air gap AG. The rotor unit 40 has a cylindrical rotor core 41. The rotor core 41 is formed by laminating a plurality of thin steel plates (magnetic material), and a total of four permanent magnets 42 are fixed to the radially outside of the rotor core 41 with an adhesive or the like. Specifically, the permanent magnets 42 are arranged at equal intervals (90° intervals) around the circumferential direction of the rotor core 41.

[0019] Additionally, the radial outer side of each permanent magnet 42 fixed to the rotor core 41 is covered with a magnet holder 43 formed into a roughly cylindrical shape from a thin stainless steel plate or the like. The magnet holder 43 prevents the permanent magnets 42 from falling off the rotor core 41. As a result, even when the rotor unit 40 rotates at high speed, the centrifugal force generated at that time will not cause the permanent magnets 42 to fall off the rotor core 41.

[0020] A shaft 44 is fixed by press fitting to the radially inner side of the rotor core 41, so that the rotor unit 40 rotates around the shaft 44. The shaft 44 is made of a round steel bar (metal) to ensure sufficient strength, and its center of rotation coincides with the center AC of the case 31 (see FIG. 5).

[0021] The axial base end side (right side in FIG. 4) of the shaft 44 is housed inside the case 31 and rotatably supported by a first metal M1 (radial bearing) housed in a bottom wall portion (bearing housing portion) 33 of the case 31. That is, the shaft 44 is rotatably supported by the case 31 via the first metal M1. The centers of the bottom wall portion 33 and the first metal M1 also coincide with the center AC of the case 31 (see FIG. 5). Here, the first metal M1 corresponds to the bearing in the present invention.

[0022] On the other hand, the axial tip side (left side in Figure 4) of the shaft 44 is accommodated inside the housing 51 that forms the reduction mechanism part 50, and is rotatably supported by the second metal M2 (radial bearing) attached to the worm accommodating part 57 of the housing 51.

[0023] Furthermore, a worm 61 that forms part of the reduction mechanism 60 is integrally provided on the axial tip side of the shaft 44. That is, the worm 61 is also made of a round steel bar, which increases the rigidity of the worm 61 and prevents the worm 61 from bending, thereby ensuring reliable meshing with the worm wheel 62.

[0024] Furthermore, a ball bearing 70 is provided in the axially intermediate portion of the shaft 44. That is, the rotor core 41 is provided alongside the ball bearing 70. The ball bearing 70 rotatably supports the shaft 44 and includes an inner race 71 formed of steel in a generally cylindrical shape, and an outer race 72 that is also formed of steel in a generally cylindrical shape like the inner race 71 but has a larger diameter than the inner race 71. Furthermore, a plurality of steel balls 73 are provided between the inner race 71 and the outer race 72 in the radial direction of the ball bearing 70.

[0025] The inner race 71 is fixed to the shaft 44 by press fitting. In other words, the inner race 71 rotates together with the shaft 44. As shown in FIG. 4, the outer diameter of the shaft 44 is larger than the outer diameter of the worm 61. Therefore, the ball bearing 70 can be press fitted into the shaft 44 from the worm 61 side in the axial direction.

[0026] Here, a sensor magnet MG is provided between the worm 61 and the ball bearing 70 in the axial direction of the shaft 44. The sensor magnet MG is used to control the rotation direction and rotation speed of the shaft 44. In other words, the ball bearing 70 is disposed between the sensor magnet MG and the rotor core 41 in the axial direction of the shaft 44.

[0027] As shown in FIG. 4, the electric motor section 30 is also provided with a bearing support member 39. The bearing support member 39 is made of a resin material such as plastic, and is attached to the housing 51 from the electric motor section 30 side (the right side in FIG. 4). The bearing support member 39 supports the outer race 72 of the ball bearing 70 in the axial direction. In other words, the bearing support member 39 functions to prevent the ball bearing 70 from rattling within the housing 51. The electric motor section 30 side of the bearing support member 39 is supported by the case 31 that forms the outer shell of the electric motor section 30.

[0028] A total of three conductive members CM are attached to the bearing support member 39. These conductive members CM are formed into rod shapes from a highly conductive material such as yellow, and one longitudinal end of each is electrically connected to the three-phase coils 38. Meanwhile, the other longitudinal end of each conductive member CM is electrically connectable to an external connector (not shown) provided on the vehicle 12 (see FIG. 1). As a result, a drive current is supplied from an on-board battery or the like to the three-phase coils 38 of the sunroof motor 20, causing the shaft 44 to rotate in the forward or reverse direction.

[0029] [Deceleration mechanism section] 2 to 4, the speed reduction mechanism 50 includes a housing 51 that houses the speed reduction mechanism 60. The housing 51 is made of a resin material such as plastic and has a generally flat rectangular parallelepiped shape, and has a first wall 52, a second wall 53, and a third wall 54. Of the first, second, and third walls 52, 53, and 54, the first wall 52 occupies the largest proportion.

[0030] As shown in FIG. 4 , a worm wheel accommodating portion 55 is provided inside the housing 51. The worm wheel accommodating portion 55 is disposed closer to the third wall portion 54. A worm wheel 62 that forms the speed reduction mechanism 60 is rotatably accommodated inside the worm wheel accommodating portion 55. The worm wheel 62 is made of a resin material such as plastic to reduce its weight. The worm wheel 62 is provided with teeth 62a that mesh with the worm 61 inside the housing 51.

[0031] That is, the reduction mechanism 60 is a worm reducer that can obtain a relatively large reduction ratio. Specifically, in this embodiment, the reduction ratio of the reduction mechanism 60 is [1:67]. That is, the reduction ratio is such that the worm wheel 62 makes one rotation after the worm 61 makes 67 rotations.

[0032] An output shaft 63 made of a round steel bar (made of metal) has its axial base end fixed to the rotation center of the worm wheel 62. On the other hand, an output gear 64 (see FIG. 2) is integrally provided at the axial tip end of the output shaft 63, with which a pair of drive cables 17a, 17b (see FIG. 1) mesh.

[0033] Therefore, the high-speed rotation of the shaft 44 is decelerated by the reduction mechanism 60, and the decelerated, high-torque rotational force is transmitted to the pair of drive cables 17a, 17b via the output shaft 63 and the output gear 64. The reduction mechanism 60 is formed by the worm 61 and the worm wheel 62.

[0034] The worm wheel accommodating portion 55 has an opening on the side opposite to the first wall portion 52 (not shown). As shown in FIG. 3, the opening of the worm wheel accommodating portion 55 is closed by a cover member 56 formed by pressing a steel plate (metal) or the like. A total of four insertion legs 56a are integrally formed on the outer periphery of the cover member 56. These insertion legs 56a extend toward the first wall portion 52 and, as shown in FIG. 4, are inserted into insertion holes HL of the housing 51 in a non-removable state.

[0035] 4, a worm accommodating portion 57 is provided inside the housing 51. The worm accommodating portion 57 is disposed closer to the second wall portion 53. The worm accommodating portion 57 is disposed near the worm wheel accommodating portion 55, and the interiors of these accommodating portions 57, 55 communicate with each other near the meshing portion of the worm 61 and the tooth portion 62a.

[0036] The worm accommodating portion 57 extends in the axial direction of the shaft 44, and a second metal M2 that rotatably supports the axial tip end side of the shaft 44 is accommodated on one axial side (the left side in FIG. 4) of the worm accommodating portion 57. The center of the second metal M2 also coincides with the center AC of the case 31 (see FIG. 5).

[0037] In this way, the shaft 44 is supported at three points by three bearings (the first metal M1, the second metal M2, and the ball bearing 70). Therefore, when the sunroof motor 20 is operating, the worm 61 is prevented from separating from the tooth portion 62a of the worm wheel 62 (disengagement from each other), and they can reliably engage with each other.

[0038] Additionally, an inner race 71 of a ball bearing 70 is fixed to the shaft 44, and an outer race 72 of the ball bearing 70 is supported by a bearing support member 39. Therefore, the shaft 44 does not move in the axial direction. This eliminates the need to provide thrust bearings on both axial sides of the shaft 44, thereby enabling a reduction in the number of parts and a reduction in weight.

[0039] On the other hand, to rotate the shaft 44 smoothly by supporting it at three points, it is necessary to improve the precision of the parts that make up the sunroof motor 20 and the precision of their assembly. Specifically, the first metal M1, the second metal M2, and the ball bearing 70 must each be positioned precisely on the center AC of the case 31, but this approach is not realistic because it would complicate the manufacturing process and increase product costs.

[0040] Therefore, in this embodiment, a support ring SR is provided between the outer race 72 and the housing 51 in a radial direction of the ball bearing 70 so as to be movable in the radial direction. Here, the support ring SR is only allowed to move slightly in the radial direction inside the housing 51, and the meshing between the worm 61 and the teeth 62a does not come out of engagement, and rattle does not occur in the meshing.

[0041] [Metal Jacket] 2 to 4, a metal jacket 80 is attached to the outside of the sunroof motor 20, specifically, the outside of the housing 51. The metal jacket 80 has the function of preventing electrical noise generated inside the sunroof motor 20 from radiating outside the housing 51. Specifically, the metal jacket 80 has the function of receiving electrical noise that attempts to escape around the resin housing 51 and dissipating (earthing) it to the vehicle body via the steel case 31.

[0042] The metal jacket 80 includes a first conductive plate 81 and a second conductive plate 82. The first and second conductive plates 81, 82 are each formed into a predetermined shape by pressing a thin steel plate (magnetic body) made of a material with excellent conductivity. The first and second conductive plates 81, 82 are electrically connected to each other so that they can be electrically conductive to each other.

[0043] [Stator support structure] Next, the support structure of the stator 35 (stator unit 34) relative to the case 31 will be described in detail with reference to the drawings.

[0044] 5, the side wall 32 forming the case 31 has a total of six flat portions 32A to 32F. Specifically, the first flat portion 32A, the second flat portion 32B, the third flat portion 32C, the fourth flat portion 32D, the fifth flat portion 32E, and the sixth flat portion 32F are arranged in this order in a clockwise direction. That is, the total of six flat portions 32A to 32F are arranged in the circumferential direction of the case 31.

[0045] The first flat portion 32A and the fourth flat portion 32D face each other around the center AC of the case 31, the second flat portion 32B and the fifth flat portion 32E face each other around the center AC of the case 31, and the third flat portion 32C and the fourth flat portion 32D face each other around the center AC of the case 31. This allows the sunroof motor 20 to be flattened (reduced in thickness).

[0046] 5, the side wall portion 32 forming the case 31 has a total of six arc portions 32a to 32f. These arc portions 32a to 32f have the function of connecting adjacent flat portions to each other in the circumferential direction of the case 31, and correspond to connecting portions in the present invention. Specifically, a first arc portion 32a, a second arc portion 32b, a third arc portion 32c, a fourth arc portion 32d, a fifth arc portion 32e, and a sixth arc portion 32f are arranged in this order in the clockwise direction.

[0047] The first arcuate portion 32a connects the first flat portion 32A and the second flat portion 32B (see part (1) in FIG. 5). The second arcuate portion 32b connects the second flat portion 32B and the third flat portion 32C (see part (2) in FIG. 5). The third arcuate portion 32c connects the third flat portion 32C and the fourth flat portion 32D (see part (3) in FIG. 5). The fourth arcuate portion 32d connects the fourth flat portion 32D and the fifth flat portion 32E (see part (4) in FIG. 5). The fifth arcuate portion 32e connects the fifth flat portion 32E and the sixth flat portion 32F (see part (5) in FIG. 5). The sixth arcuate portion 32f connects the sixth flat portion 32F and the first flat portion 32A (see part (6) in FIG. 5).

[0048] Furthermore, an inner circumferential surface CF is provided radially inward of each of the first to sixth arcuate portions 32a to 32f, and the inner circumferential surfaces CF of these arcuate portions 32a to 32f are all formed in an arc shape with a radius R1 centered on the center AC of the case 31 when viewed in the axial direction of the shaft 44 (see FIG. 6). The first to sixth arcuate portions 32a to 32f all have the same length dimension L1 along the circumferential direction of the case 31 (see FIG. 6).

[0049] In contrast, a total of six flat surfaces FS1 to FS6 and a total of six arcuate surfaces AS1 to AS6 are provided on the radially outer side of the stator 35 housed inside the case 31. Specifically, a first flat surface FS1, a second flat surface FS2, a third flat surface FS3, a fourth flat surface FS4, a fifth flat surface FS5, and a sixth flat surface FS6 are arranged in this order in the clockwise direction.

[0050] The first arc surface AS1 is disposed between the first flat surface FS1 and the second flat surface FS2 (see the part (1) of FIG. 5). The second arc surface AS2 is disposed between the second flat surface FS2 and the third flat surface FS3 (see the part (2) of FIG. 5). The third arc surface AS3 is disposed between the third flat surface FS3 and the fourth flat surface FS4 (see the part (3) of FIG. 5). The fourth arc surface AS4 is disposed between the fourth flat surface FS4 and the fifth flat surface FS5 (see the part (4) of FIG. 5). The fifth arc surface AS5 is disposed between the fifth flat surface FS5 and the sixth flat surface FS6 (see the part (5) of FIG. 5). The sixth arc surface AS6 is disposed between the sixth flat surface FS6 and the first flat surface FS1 (see the part (6) of FIG. 5).

[0051] In the axial direction view of the shaft 44, the first to sixth arc surfaces AS1 to AS6 are all formed in an arc shape with a radius R1 centered on the center AC of the case 31 (see FIG. 6). Therefore, the first to sixth arc surfaces AS1 to AS6 are respectively supported by surface contact on the inner peripheral surface CF of the first to sixth arc portions 32a to 32f. That is, the stator 35 is supported only by the respective inner peripheral surfaces CF (a total of six). Here, the length dimensions of the first to sixth arc surfaces AS1 to AS6 along the circumferential direction of the stator 35 are all the same length dimension L2.

[0052] However, the length dimension L2 of the first to sixth arc surfaces AS1 to AS6 is smaller than the length dimension L1 of the first to sixth arc portions 32a to 32f (L2 < L1). As a result, the contact portion of the stator 35 with respect to the case 31 is reduced as compared with the prior art. Therefore, when the stator unit 34 is inserted into the case 31 and assembled, the press-fitting load at that time can be reduced as compared with the prior art. At that time, since the first to sixth arc surfaces AS1 to AS6 are in surface contact with the inner peripheral surfaces CF of the first to sixth arc portions 32a to 32f respectively, the first to sixth arc surfaces AS1 to AS6 do not scrape the inner peripheral surfaces CF.

[0053] Furthermore, simply by assembling the stator unit 34 to the case 31, the centers AC of the two are automatically aligned. This eliminates the axial misalignment (misalignment of the centers AC) that occurred in the past between the stator unit 34 and the case 31.

[0054] 7, the case 31 is provided with a bottom wall portion 33 that houses a first metal M1 that rotatably supports the end of the shaft 44, and the bottom wall portion 33 is formed in a cylindrical shape centered on the center AC of the case 31 when viewed in the axial direction of the shaft 44. Therefore, the center of the rotor unit 40 can also be accurately positioned at the center AC of the case 31. That is, in this embodiment, the centers of the case 31, the stator unit 34, and the rotor unit 40 can be accurately aligned with each other.

[0055] 5, gaps G1 to G6 are formed between the first to sixth flat portions 32A to 32F and the first to sixth flat surfaces FS1 to FS6 of the stator 35, respectively, in the radial direction of the shaft 44. When viewed in the axial direction of the shaft 44, each of the six gaps G1 to G6 has a minute dimension W1 in the radial direction of the shaft 44. Specifically, the minute dimension W1 is smaller than the wall thickness of the case 31.

[0056] Each of the gaps G1 to G6 is filled with an adhesive (not shown) made of epoxy resin or the like when assembling the sunroof motor 20. This prevents the stator 35 (stator unit 34) from coming off the case 31 and also prevents the stator 35 and the stator unit 34 from rattling in the circumferential direction.

[0057] [Assembly Instructions] Next, the procedure for assembling the sunroof motor 20 formed as above, in particular the procedure for assembling the stator 35 (stator unit 34) into the case 31 will be described in detail with reference to FIGS.

[0058] 8, first, the stator unit 34 and the case assembly CA, which have been assembled in advance in a separate manufacturing process, are prepared. Here, the case assembly CA is formed by attaching the first metal M1 (see FIGS. 4 and 7) to the bottom wall portion 33 of the case 31.

[0059] Here, a crossover wire LN that connects coils 38 of the same phase is provided on one longitudinal side (left side in Figure 8) of the stator unit 34, and a flange portion FL that abuts against the housing 51 (see Figure 4) of the reduction mechanism section 50 is provided on one longitudinal side (left side in Figure 8) of the case 31.

[0060] Then, as shown by arrow AR1 in Fig. 8, the stator unit 34 is brought into contact with the case 31. At this time, the other longitudinal side (right side in the figure) of the stator unit 34 is brought into contact with one longitudinal side (left side in the figure) of the case 31. Also, as shown in Fig. 5, the first to sixth arcuate surfaces AS1 to AS6 are aligned with the inner circumferential surfaces CF of the first to sixth arcuate portions 32a to 32f, respectively.

[0061] 9, an attachment jig (not shown) is pressed against the exposed portion of the stator 35, i.e., the portion of the stator 35 not covered with the insulator 37 (the shaded portion in FIG. 9), on one longitudinal side of the stator unit 34, and the stator unit 34 is inserted into the case 31. Specifically, the attachment jig is used to evenly press the pressure points PP provided in the shaded portion in FIG. 9.

[0062] This allows the stator unit 34 to be attached to the case 31 with a relatively small press-fit load (smaller than before), and the center of the stator unit 34 to coincide with the center AC of the case 31. Even if the stator unit 34 is slightly misaligned in the circumferential direction so as to rotate relative to the case 31, the centers of the two will not be misaligned with each other. Therefore, the stator unit 34 can be easily assembled to the case 31.

[0063] 5, in this embodiment, the stator 35 is supported only by a total of six inner circumferential surfaces CF, and the center AC of the case 31 is located within an area VP1 (area surrounded by a thick two-dot chain line) surrounded by straight lines connecting a total of six support points (supported portions) SP of the stator 35 supported by the inner circumferential surfaces CF, as viewed in the axial direction of the shaft 44. Here, the support points SP of the stator 35 are points at the circumferential center of the first to sixth arcuate surfaces AS1 to AS6 that form the stator 35.

[0064] This allows the stator unit 34 to be press-fitted into the case 31 in a well-balanced and accurate manner, and allows the center of the stator 35 (stator unit 34) to coincide with the center AC of the case 31.

[0065] As described above in detail, according to the present embodiment, the case 31 has a total of six first to sixth flat portions 32A to 32F arranged in the circumferential direction of the case 31 and a total of six first to sixth arc portions 32a to 32f connecting adjacent flat portions to each other, and the inner circumferential surfaces CF of these first to sixth arc portions 32a to 32f are all formed in an arc shape of radius R1 centered on the center AC of the case 31 when viewed in the axial direction of the shaft 44. Furthermore, since the stator 35 is supported only by these inner circumferential surfaces CF (six in total), it is possible to reduce the press-fit load of the stator 35 into the case 31 and improve assembly precision.

[0066] Furthermore, according to the present embodiment, gaps G1 to G6 are provided between the first to sixth flat portions 32A to 32F and the first to sixth flat surfaces FS1 to FS6 of the stator 35, respectively, in the radial direction of the shaft 44. This allows an adhesive such as epoxy resin to be filled into each of the gaps G1 to G6. This reliably prevents the stator 35 (stator unit 34) from coming off the case 31, and more reliably prevents rattling between them in the circumferential direction.

[0067] Furthermore, according to this embodiment, the case 31 includes a bottom wall portion 33 that houses the first metal M1 that rotatably supports the end of the shaft 44, and the bottom wall portion 33 is formed in a cylindrical shape centered on the center AC of the case 31 when viewed in the axial direction of the shaft 44. This allows the center of the rotor unit 40 to be accurately positioned at the center AC of the case 31. Therefore, the centers of the case 31, the stator unit 34, and the rotor unit 40 can be accurately aligned, which in turn reduces variation in the rotational resistance of the electric motor portion 30 between products.

[0068] Furthermore, according to this embodiment, the stator 35 is supported on the inner circumferential surfaces CF of the first to sixth arc portions 32a to 32f, and the center AC of the case 31 is located within an area VP1 surrounded by straight lines connecting a total of six support points SP of the stator 35 supported on the inner circumferential surfaces CF, as viewed in the axial direction of the shaft 44. This allows the stator unit 34 to be press-fitted into the case 31 in a balanced and accurate manner, and the center of the stator 35 can be reliably aligned with the center AC of the case 31.

[0069] Furthermore, according to this embodiment, as described above, the press-fit load of the stator 35 onto the case 31 can be reduced, thereby saving energy required to manufacture the electric motor unit 30, and the variation in rotational resistance of the electric motor unit 30 between products can be suppressed, thereby reducing the occurrence of defective products. This makes it possible to achieve the Sustainable Development Goals (SDGs) established by the United Nations, particularly Goal 7 (Ensure access to affordable, reliable, sustainable and modern energy for all) and Goal 13 (Take urgent action to combat climate change and its impacts).

[0070] [Embodiment 2] Next, a second embodiment of the present invention will be described in detail with reference to the drawings. Note that parts having the same functions as those in the first embodiment will be given the same reference numerals, and detailed description thereof will be omitted.

[0071] FIG. 10 shows a cross-sectional view corresponding to FIG. 6 showing Embodiment 2.

[0072] As shown in FIG. 10, the electric motor unit (brushless motor) 90 of Embodiment 2 supports the stator 91 only by a total of three inner peripheral surfaces CF, namely, the inner peripheral surface CF of the second arc portion 32b forming the case 31, the inner peripheral surface CF of the fourth arc portion 32d, and the inner peripheral surface CF of the sixth arc portion 32f. Specifically, the second arc portion 32b, the fourth arc portion 32d, and the sixth arc portion 32f are arranged at intervals of 120° in the circumferential direction of the case 31, and the second arc surface AS2, the fourth arc surface AS4, and the sixth arc surface AS6 of the stator 91 are in surface contact with each of these inner peripheral surfaces CF.

[0073] Thereby, in the axial view of the shaft 44, the center AC of the case 31 is arranged within a region VP2 (a region surrounded by a thick two-dot chain line) surrounded by a straight line connecting a total of three supported points SP of the stator 91 supported by a total of three inner peripheral surfaces CF.

[0074] Here, gaps G7 to G9 having a minute dimension W2 (W2 > W1) are formed between the first arc surface AS1 of the stator 91 and the first arc portion 32a of the case 31, between the third arc surface AS3 of the stator 91 and the third arc portion 32c of the case 31, and between the fifth arc surface AS5 of the stator 91 and the fifth arc portion 32e of the case 31.

[0075] Also, the first arc surface AS1, the third arc surface AS3, and the fifth arc surface AS5 of the stator 91 are each formed in an arc shape having a radius R (R2 < R1) centered on the center AC of the case 31 in the axial view of the shaft 44.

[0076] <000——And, also in these gaps G7 to G9, an adhesive (not shown) made of an epoxy resin or the like is filled at the time of assembling the sunroof motor 20 (electric motor unit 90).

[0077] The second embodiment configured as described above can also achieve the same effects as the first embodiment. In addition, in the second embodiment, the supported points SP of the stator 35 are provided in three locations spaced apart at 120° intervals, so that the positional accuracy of the stator 91 relative to the case 31 can be ensured while the press-fit load can be further reduced compared to the first embodiment. This can further improve the ease of assembly of the electric motor section 90.

[0078] [Embodiment 3] Next, a third embodiment of the present invention will be described in detail with reference to the drawings. Note that parts having the same functions as those in the first embodiment will be given the same reference numerals, and detailed description thereof will be omitted.

[0079] FIG. 11 shows a cross-sectional view corresponding to FIG. 6 showing the third embodiment.

[0080] 11 , electric motor unit (brushless motor) 100 of the third embodiment supports stator 101 only by a total of four inner circumferential surfaces CF, namely, inner circumferential surface CF of first arc-shaped portion 32a, inner circumferential surface CF of second arc-shaped portion 32b, inner circumferential surface CF of fourth arc-shaped portion 32d, and inner circumferential surface CF of fifth arc-shaped portion 32e, which form case 31. Specifically, first arc-shaped portion 32a, second arc-shaped portion 32b, fourth arc-shaped portion 32d, and fifth arc-shaped portion 32e are arranged in this order in the circumferential direction of case 31, and first arc-shaped surface AS1, second arc-shaped surface AS2, fourth arc-shaped surface AS4, and fifth arc-shaped surface AS5 of stator 101 are in surface contact with these inner circumferential surfaces CF, respectively. In other words, the stator 101 is in surface contact with each of the inner surfaces CF of the arc portions (first arc portion 32a and fourth arc portion 32d, second arc portion 32b and fifth arc portion 32e) that are located at positions that are point-symmetrical about the center AC of the case 31.

[0081] As a result, when viewed in the axial direction of the shaft 44, the center AC of the case 31 is positioned within the area VP3 (area surrounded by thick dashed double-dashed lines) surrounded by straight lines connecting a total of four supported points SP of the stator 101 supported on a total of four inner surfaces CF.

[0082] Here, between the third arc surface AS3 of the stator 101 and the third arc portion 32c of the case 31, and between the sixth arc surface AS6 of the stator 101 and the sixth arc portion 32f of the case 31, gaps G10 and G11 with a minute dimension W2 (W2 > W1) are formed.

[0083] Also, both the third arc surface AS3 and the sixth arc surface AS6 of the stator 101 are formed in an arc shape with a radius R2 (R2 < R1) centered on the center AC of the case 31 when viewed in the axial direction of the shaft 44.

[0084] And, also in these gaps G10 and G11, an adhesive (not shown) made of an epoxy resin or the like is filled during the assembly of the sunroof motor 20 (electric motor unit 100).

[0085] Even in the third embodiment formed as described above, the same operational effects as those of the above-described second embodiment can be achieved.

[0086] [Undesirable Stator Support Structure] Here, those (Comparative Example 1 and Comparative Example 2) that are not desirable as the stator support structure will be described in detail using the drawings. Note that parts having the same functions as those in the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0087] FIG. 12 shows a diagram for explaining the stator support portion of Comparative Example 1, and FIG. 13 shows a diagram for explaining the stator support portion of Comparative Example 2.

[0088] [Comparative Example 1] In Comparative Example 1 shown in FIG. 12, the stator 110 is provided with a first arc surface AS1, a second arc surface AS2, and a third arc surface AS3 having a radius R1 centered on the center AC of the case 31, and these are designed to be in surface contact with the inner peripheral surface CF of the first arc portion 32a, the inner peripheral surface CF of the second arc portion 32b, and the inner peripheral surface CF of the third arc portion 32c of the case 31, respectively.

[0089] In addition, the stator 110 is also provided with a fourth arc surface AS4, a fifth arc surface AS5, and a sixth arc surface AS6 having a radius R2 (R2 < R1) centered on the center AC of the case 31. That is, as shown in FIG. 12, when the center AC of the case 31 coincides with the center of the stator 110, between the fourth arc surface AS4 and the fourth arc portion 32d, between the fifth arc surface AS5 and the fifth arc portion 32e, and between the sixth arc surface AS6 and the sixth arc portion 32f, gaps G12, G13, and G14 having a minute dimension W2 (W2 > W1) are respectively formed.

[0090] In such Comparative Example 1, in the axial view of the shaft 44 (see FIG. 5), the center AC of the case 31 is arranged outside the region VP4 (the region surrounded by the thick two-dot chain line) surrounded by the straight line connecting the total three supported points SP of the stator 110 supported by the total three inner peripheral surfaces CF. Therefore, the stator 110 may move in the direction of the arrow AR2 in FIG. 12 with respect to the case 31, and the center of the stator 110 may easily deviate from the center AC of the case 31. Thus, the design as in Comparative Example 1 (FIG. 12) is not desirable.

[0091] [Comparative Example 2] In Comparative Example 2 shown in FIG. 13, the stator 120 is provided with a second arc surface AS2, a third arc surface AS3, a fourth arc surface AS4, and a fifth arc surface AS5 having a radius R1 centered on the center AC of the case 31, and these are designed to be in surface contact with the inner peripheral surfaces CF of the second arc portion 32b, the third arc portion 32c, the fourth arc portion 32d, and the fifth arc portion 32e of the case 31, respectively.

[0092] In addition, the stator 120 is also provided with a first arc surface AS1 and a sixth arc surface AS6 having a radius R2 (R2 < R1) centered on the center AC of the case 31. That is, as shown in FIG. 13, when the center AC of the case 31 coincides with the center of the stator 120, between the first arc surface AS1 and the first arc portion 32a and between the sixth arc surface AS6 and the sixth arc portion 32f, gaps G15 and G16 having a minute dimension W2 (W2 > W1) are respectively formed.

[0093] In such Comparative Example 2, when viewed in the axial direction of shaft 44 (see FIG. 5), center AC of case 31 is located on a line in area VP5 (area surrounded by a thick two-dot chain line) surrounded by straight lines connecting a total of four supported points SP of stator 120 supported by a total of four inner circumferential surfaces CF (center AC is not located within area VP5). Therefore, stator 120 moves in the direction of arrow AR3 in FIG. 13 relative to case 31, and there is a risk that the center of stator 120 may easily deviate from center AC of case 31. Therefore, a design such as that of Comparative Example 2 (FIG. 13) is not desirable.

[0094] The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit and scope of the present invention. In the above-described embodiment, the present invention is applied to the sunroof motor 20 used in the sunroof device 10 of the vehicle 12, but the present invention is not limited to this, and can also be applied to, for example, an in-vehicle motor used in a sliding door device, a power window device, a wiper device, etc., mounted on the vehicle.

[0095] Furthermore, the material, shape, size, number, installation location, etc. of each component in the above-described embodiments are arbitrary as long as they can achieve the present invention, and are not limited to the above-described embodiments. [Explanation of symbols]

[0096] 10: Sunroof device, 11: Roof panel, 12: Vehicle, 13: Roof, 14: Opening, 15a, 15b: Shoes, 16: Guide rails, 17a, 17b: Drive cables, 20: Sunroof motor, 30: Electric motor section (brushless motor), 31: Case, 32: Side wall section, 32a: First arc section (connection section), 32A: First flat section, 32b: Second arc section (connection section), 32B: Second flat section, 32c: Third arc section (connection section), 32C: Third flat section, 32d: Fourth arc section (connection section), 32D: Fourth flat section, 32e: Fifth arc section (connection section), 32E: Fifth flat section portion, 32f: sixth arc portion (connection portion), 32F: sixth flat portion, 33: bottom wall portion (bearing accommodating portion), 34: stator unit, 35: stator, 36: teeth, 37: insulator, 38: coil, 39: bearing support member, 40: rotor unit, 41: rotor core, 42: permanent magnet, 43: magnet holder, 44: shaft, 50: reduction mechanism portion, 51: housing, 52: first wall portion, 53: second wall portion, 54: third wall portion, 55: worm wheel accommodating portion, 56: cover member, 56a: insertion leg, 57: worm accommodating portion, 60: reduction mechanism, 61: Worm, 62: worm wheel, 62a: tooth portion, 63: output shaft, 64: output gear, 70: ball bearing, 71: inner race, 72: outer race, 73: steel ball, 80: metal jacket, 81: first conductive plate, 82: second conductive plate, 90: electric motor part (brushless motor), 91: stator, 100: electric motor part (brushless motor), 101: stator, 110: stator, 120: stator, AC: center of case 31, AG: air gap, AS1: first arc surface, AS2: second arc surface, AS3: third arc surface, AS4: 4th arc surface, AS5: 5th arc surface, AS6: 6th arc surface, CA: case assembly, CF: inner surface, CM: conductive material, FG: front glass, FL: flange, FS1: 1st flat surface, FS2: 2nd flat surface, FS3: 3rd flat surface, FS4: 4th flat surface, FS5: 5th flat surface, FS6: 6th flat surface, G1 to G16: gap, HL: insertion hole, HP: hollow section, LN: crossover wire, M1: 1st metal (bearing), M2: 2nd metal, MG: sensor magnet, PP: pressure point, SP: supported point (supported part), SR: support ring, VP1 to VP5: area

Claims

1. a stator having a hollow portion; a case that houses the stator; a shaft rotatably housed in the hollow portion and rotatably supported by the case; A brushless motor comprising: the case has a total of six flat portions arranged in a circumferential direction of the case and a total of six connection portions connecting adjacent flat portions to each other, Each of the inner circumferential surfaces of the six connecting portions is formed in an arc shape centered on the center of the case when viewed in the axial direction of the shaft, The stator is supported only by at least three of the inner circumferential surfaces, When viewed in the axial direction of the shaft, the center of the case is located within an area surrounded by straight lines connecting at least three supported portions of the stator supported on the inner peripheral surface. Brushless motor.

2. 2. The brushless motor according to claim 1, A gap is provided between the flat portion and the stator in the radial direction of the shaft. Brushless motor.

3. 3. The brushless motor according to claim 2, the case includes a bearing accommodating portion that accommodates a bearing that rotatably supports an end of the shaft, The bearing accommodating portion is formed in a cylindrical shape centered on the center of the case when viewed in the axial direction of the shaft. Brushless motor.

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