Insulator, stator, and electric motor

Abstract

To provide an insulator, a stator, and an electric motor capable of improving molding accuracy and assembling easiness.SOLUTION: An insulator 26 comprises a first insulator 61 and a second insulator 62 mounted from axially both sides of a stator core. The first insulator 61 has a first core end-surface covering portion 65 and a first skirt portion 79. The second insulator 62 has a second core end-surface covering portion 265 and a second skirt portion 279. The insulator has a coil drawing-out portion 77 integrally installed only on the first core end-surface covering portion 65 to draw out a terminal portion of a coil from the first insulator 61 to the outside. An axially longest portion of the second skirt portion 279 is longer in length than an axially longest portion of the first skirt portion 79.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an insulator, a stator, and an electric motor. [Background technology]

[0002] The electric motor includes, for example, a stator around which a coil is wound, and a rotor having a permanent magnet that is rotatable relative to the stator. The stator is made of a magnetic material and has an annular core body and teeth that protrude radially from the core body. The coil is wound around the teeth from above an insulator. The insulator is made of an insulating resin. The insulator insulates the teeth from the coil. With this configuration, when current is applied to the coil, a magnetic field is generated in the teeth. Magnetic attractive and repulsive forces are generated between this magnetic field and the permanent magnet, causing the rotor to rotate continuously.

[0003] In many cases, the insulator is split in the axial direction so that it can surround the teeth, and is attached to both axial sides of the core body. One of the two split insulators is integrally molded with a coil lead-out section (pillar, claw) that pulls out the coil from the insulator to gather the coil terminals and electrically connect them to an external power source. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-7427 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the above-mentioned conventional technology, the insulator integrally formed with the coil lead-out portion has a complex shape, which causes a problem of poor molding precision. Furthermore, there is a possibility that the deformation of the insulator after molding may become large, which may result in a problem that the insulator's assembly performance may be impaired due to the deformation of the insulator after molding.

[0006] Therefore, the present invention provides an insulator, a stator, and an electric motor that can improve molding precision and assembly ease. [Means for solving the problem]

[0007] In order to solve the above problems, an insulator according to the present invention is a resin insulator that is attached to a stator core having an annular core body and a plurality of teeth protruding from the core body in a radial direction, and that provides insulation between the stator core and coils wound around the teeth, and includes a first insulator and a second insulator that are attached to both axial sides of the stator core, and the first insulator includes a first core end face covering portion that covers a first axial end face of the core body, and a second insulator that extends in the axial direction from the first core end face covering portion toward the second insulator and covers a circumferential surface of the core body and a circumferential side of the teeth. the second insulator has a second core end face covering portion that covers a second end face of the core body opposite the first end face in the axial direction, and a second skirt portion that extends axially from the second core end face covering portion toward the first insulator and covers the circumferential surface of the core body and the circumferential side surfaces of the teeth, and has a coil pull-out portion that is integrally formed only with the first core end face covering portion and is used to pull out a terminal end of the coil from the first insulator to the outside, and the length of the longest point in the axial direction of the second skirt portion is longer than the length of the longest point in the axial direction of the first skirt portion. [Effects of the Invention]

[0008] According to the present invention, the molding precision and assembly ease of the insulator, the stator, and the electric motor can be improved. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view of a motor with a reducer according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 2 is a perspective view of a stator according to an embodiment of the present invention. [Figure 4] 1 is a plan view of a stator according to an embodiment of the present invention, viewed from an axial direction, with a terminal holder removed. [Figure 5] 1 is a partially enlarged plan view of a stator core according to a first embodiment of the present invention, as viewed from the axial direction. [Figure 6] 1 is a perspective view of an insulator according to a first embodiment of the present invention. [Figure 7] FIG. 2 is a perspective view of a first insulator according to the first embodiment of the present invention, as viewed from above. [Figure 8] FIG. 3 is a perspective view of a second insulator according to the first embodiment of the present invention, as viewed from below. [Figure 9] 5 is a graph showing changes in a deformation ratio obtained by dividing the deformation amount of a second insulator by the deformation amount of a first insulator in the first embodiment of the present invention. [Figure 10] 4 is a graph comparing the amount of deformation of each insulator in a conventional product and the first embodiment of the present invention. [Figure 11] FIG. 10 is a perspective view of a second insulator according to a second embodiment of the present invention, as viewed from above. [Figure 12] FIG. 10 is a partially enlarged plan view of a stator core to which a second insulator is attached, as viewed from the axial direction, according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Next, an embodiment of the present invention will be described with reference to the drawings.

[0011] <Motor with reducer> Fig. 1 is a perspective view of a speed reducer-equipped motor 1. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. The motor 1 with a speed reducer is used, for example, as a drive source for a wiper device of a vehicle. As shown in FIGS. 1 and 2, the motor with a reducer 1 includes an electric motor 2, a speed reducer unit 3 that reduces the rotation of the electric motor 2 and outputs the reduced rotation, and a controller 4 that controls the drive of the electric motor 2. In the following description, the term "axial direction" refers to a direction parallel to the central axis of the shaft 31 of the electric motor 2 (the rotation axis C1 of the electric motor 2). The term "circumferential direction" refers to the circumferential direction (rotation direction) of the shaft 31. The term "radial direction" refers to the radial direction of the shaft 31 that is perpendicular to the axial and circumferential directions.

[0012] <Electric motor> The electric motor 2 includes a motor case 5, a cylindrical stator 8 housed in the motor case 5, and a rotor 9 disposed radially inside the stator 8 and rotatable relative to the stator 8. The electric motor 2 is a so-called brushless motor, which does not require brushes to supply power to the stator 8.

[0013] <Motor case> The motor case 5 is made of a material with excellent heat dissipation properties, such as an aluminum alloy. The motor case 5 is made up of a first motor case 6 and a second motor case 7, which are configured to be separable in the axial direction. The first motor case 6 and the second motor case 7 are each formed in a cylindrical shape with a bottom.

[0014] The first motor case 6 has a bottom 10 integrally formed with the gear case 40 of the reduction gear unit 3. A through hole 10a is formed in the radial center of the bottom 10, allowing the shaft 31 of the electric motor 2 to be inserted therethrough. Outer flanges 16, 17 that protrude radially outward are formed in the openings 6a, 7a of the first motor case 6 and the second motor case 7, respectively. These outer flanges 16, 17 are butted against each other, and the first motor case 6 and the second motor case 7 are integrated with each other by bolts 25. The motor case 5 has an internal space closed by the first motor case 6 and the second motor case 7, and the stator 8 and rotor 9 are housed in this internal space.

[0015] <Rotor> The rotor 9 is rotatably disposed radially inside the stator 8 via a small gap. The rotor 9 includes a shaft 31, a cylindrical rotor core 32 fitted and fixed to the shaft 31, a plurality of magnets (not shown) assembled to the outer periphery of the rotor core 32, and a magnet cover 32a that covers the rotor core 32 from above the magnets.

[0016] The shaft 31 is formed integrally with the worm shaft 44 that constitutes the speed reducer 3. However, this is not a limitation, and the worm shaft 44 may be formed separately from the shaft 31 and connected to the end of the shaft 31. The shaft 31 and the worm shaft 44 are rotatably supported by the gear case 40 via bearings 46, 47. The shaft 31 and the worm shaft 44 rotate around the rotation axis C1. For example, a ferrite magnet is used as the magnet. However, this is not a limitation, and the magnet may also be a neodymium bonded magnet, a neodymium sintered magnet, or the like.

[0017] <Deceleration part> The reduction unit 3 includes a gear case 40 integrated with the motor case 5 and a worm reduction mechanism 41 housed within the gear case 40. The gear case 40 is made of a metal material with excellent heat dissipation properties, such as an aluminum alloy. The gear case 40 is formed in a box shape with an opening 40a on one side. The gear case 40 has a gear housing portion 42 that houses the worm reduction mechanism 41 inside. In addition, an opening 43 that connects the through hole 10a of the first motor case 6 to the gear housing portion 42 is formed in the side wall 40b of the gear case 40 at the location where the first motor case 6 is integrally formed.

[0018] A cylindrical bearing boss 49 is formed to protrude from the bottom wall 40c of the gear case 40. The bearing boss 49 rotatably supports the output shaft 48 of the worm reduction mechanism 41, and a plain bearing (not shown) is disposed on the inner periphery. An O-ring (not shown) is attached to the inner periphery of the tip of the bearing boss 49. In addition, a plurality of ribs 52 protrude from the outer periphery of the bearing boss 49 to ensure rigidity.

[0019] The worm reduction mechanism 41 housed in the gear housing 42 is composed of a worm shaft 44 formed integrally with the shaft 31 of the rotor 9, and a worm wheel 45 meshed with the worm shaft 44. Both axial ends of the worm shaft 44 are supported by the gear case 40 via bearings 46, 47 so as to be rotatable about a rotation axis C1. An output shaft 48 of the electric motor 2 is coaxially and integrally provided on the worm wheel 45. The worm wheel 45 and the output shaft 48 are arranged so that their rotation axes are perpendicular to the rotation axis C1 of the worm shaft 44 (shaft 31 of the electric motor 2). The output shaft 48 protrudes to the outside through a bearing boss 49 of the gear case 40. A spline 48a is formed at the protruding tip of the output shaft 48, which can be connected to an object to be driven by the motor.

[0020] In addition, a sensor magnet (not shown) is provided on the worm wheel 45. The position of this sensor magnet is detected by a magnetic detection element 50 (described later) provided in the controller 4. In other words, the rotational position of the worm wheel 45 is detected by the magnetic detection element 50 of the controller 4.

[0021] <controller> The controller 4 has a controller board 51 on which a magnetic detection element 50 is mounted. The controller board 51 is disposed in the opening 40a of the gear case 40 so that the magnetic detection element 50 faces the sensor magnet of the worm wheel 45. The opening 40a of the gear case 40 is closed by a cover 53.

[0022] The controller board 51 is electrically connected to the coil 24 (described later) of the stator 8. The terminals of a connector 11 (see FIG. 1) provided on a cover 53 are also electrically connected to the controller board 51. In addition to the magnetic detection element 50, the controller board 51 is also mounted with a power module (not shown) made up of switching elements such as FETs (Field Effect Transistors) that control the drive voltage supplied to the coil 24, a capacitor (not shown) that smooths the voltage, and the like.

[0023] <Stator and terminal holder> Fig. 3 is a perspective view of the stator 8. Fig. 4 is a plan view of the stator 8 as seen from the axial direction, showing a state in which the terminal holder 85 has been removed. As shown in Figures 3 and 4, the stator 8 includes a cylindrical stator core 20 whose central axis coincides with the rotation axis C1, an insulator 26 attached to the stator core 20, and a plurality of coils 24 having a three-phase (U phase, V phase, W phase) structure wound around the stator core 20 from above the insulator 26.

[0024] A terminal holder 85 is provided on the stator core 20. The terminal holder 85 is integrally formed with terminals 86, a holder body 87 that holds the terminals 86, and a cover portion 88 that covers one axial end portion of the stator core 20. The terminals 86 are connected to the terminal portions 24a of the coils 24 of each phase, and are also connected to a connector (not shown) extending from the controller board 51. The cover portion 88 is integrally formed with an annular end face cover portion 88a arranged opposite to the axial direction of the stator core 20, and an outer circumferential cover portion 88b extending from the outer peripheral edge of the end face cover portion 88a toward the stator core 20 and covering the insulator 26 from the radially outer side.

[0025] The holder body 87 is formed by rising from a part of the end face cover portion 88a toward the opposite side to the stator core 20. The end face cover portion 88a and the outer circumferential cover portion 88b have cut-out portions 88c formed at locations corresponding to the holder body 87. The holder main body 87 is formed in the shape of a rectangular parallelepiped that is long in the axial and circumferential directions. A connector (not shown) extending from the controller board 51 is attached to the holder main body 87. The holder main body 87 is formed with three terminal accommodating recesses 87a that are aligned in the longitudinal direction when viewed from the axial direction. The terminals 86 are accommodated and held in these terminal accommodating recesses 87a. The terminals 86 are then connected to a connector (not shown) extending from the controller board 51.

[0026] Fig. 5 is a partially enlarged plan view of the stator core 20 as viewed from the axial direction. Fig. 5 shows only a first insulator 61 (described later) of the insulators 26 attached to the stator core 20. Fig. 5 also shows the stator core 20 as viewed from the side of a second insulator 62 (described later) of the insulators 26. 3 to 5, the stator core 20 is formed by laminating a plurality of electromagnetic steel sheets 20p. However, this is not limitative, and the stator core 20 may be formed by, for example, pressure-molding soft magnetic powder.

[0027] The stator core 20 has a cylindrical core body 21, a plurality of teeth 22 (six in this first embodiment) protruding radially inward from the inner surface 19 of the core body 21, and two fixing portions 23 integrally molded on the outer peripheral surface of the core body 21. The inner circumferential surface 19 of the core body 21 is not arc-shaped but slightly polygonal. That is, the inner circumferential surface 19 of the core body 21 has two first circumferential surfaces 19a extending from a circumferential center C2 between adjacent teeth 22 toward the teeth 22, and two second circumferential surfaces 19b extending further from the first circumferential surfaces 19a toward the teeth 22 and connected to the bases of the teeth 22. The angle θ1 between the two first circumferential surfaces 19a is greater than the angle θ2 between the first circumferential surface 19a and the second circumferential surface 19b.

[0028] The teeth 22 have tooth bodies 28 that protrude radially from the inner circumferential surface 19 of the core body 21, and flanges 29 that are integrally molded with tooth tip portions 28a, which are the radially inner ends of the tooth bodies 28 on the opposite side from the core body 21. Two circumferential side surfaces 28b of the tooth bodies 28 are parallel to each other and are also parallel to the radial direction. The coils 24 are wound around the tooth bodies 28 from above the insulators 26.

[0029] The flange 29 extends in the circumferential direction. The inner peripheral surface of the flange 29 is formed along a circle centered on the rotation axis C1. Between adjacent teeth 22 in the circumferential direction, a dovetail-shaped slot 27 is formed by the inner peripheral surface of the core body 21, the circumferential side surface 28b of the tooth body 28, and the outer peripheral surface of the flange 29 when viewed in the axial direction.

[0030] The fixing portions 23 protrude radially outward from the outer peripheral surface of the core body 21 and are arranged at 180° intervals in the circumferential direction. The fixing portions 23 are formed with bolt insertion holes 23a that penetrate in the axial direction.

[0031] With this configuration, the outer peripheral surface of the core body 21 is fitted into and housed within the inner peripheral surface of the first motor case 6. Then, a tapping screw (not shown) is inserted into the bolt insertion hole 23a of the fixing portion 23, and this tapping screw is screwed into the bottom portion 10 of the first motor case 6, thereby fastening and fixing the stator core 20 to the first motor case 6. The second motor case 7 is then placed over the stator core 20 fixed in this manner. The second motor case 7 is then fixed to the first motor case 6.

[0032] [First embodiment] <Insulator> 6 is a perspective view of the insulator 26. FIG. 6 shows the insulator 26 attached to the stator core 20. The insulator 26 is intended to insulate the stator core 20 from the coil 24, and is made of insulating resin.

[0033] 6, the insulator 26 is configured to be divided into two parts in the axial direction so as to be attached to both axial sides of the stator core 20. That is, the insulator 26 includes a first insulator 61 attached to one axial side of the stator core 20 (upper side in FIG. 5) and a second insulator 62 attached to the other axial side of the stator core 20 (lower side in FIG. 5). In the following, for ease of understanding, the first insulator 61 side will be referred to as the upper side, and the second insulator 62 side will be referred to as the lower side (the same applies to the second embodiment below).

[0034] First, the first insulator 61 will be described with reference to FIGS. FIG. 7 is a perspective view of the first insulator 61 as viewed from above. 5 to 7, the first insulator 61 is formed by integrally molding a core body covering portion 63 that covers the core body 21 and tooth covering portions 64 that cover the teeth 22. The core body covering portion 63 has an annular first core end face covering portion 65 that covers one axial end face (an example of the first end face in the claims) 21a of the core body 21, a core side face covering portion 66 that protrudes downward from the abutment surface 65a of the first core end face covering portion 65 with the core body 21, and a cylindrical outer wall portion 67 that protrudes upward from the abutment surface 65a of the first core end face covering portion 65.

[0035] The core side surface covering portion 66 is disposed on the inner peripheral edge of the first core end surface covering portion 65. The core side surface covering portion 66 is formed along the inner peripheral surface 19 of the core body 21 and covers this inner peripheral surface 19. The core side surface covering portion 66 is formed in a slightly polygonal shape to correspond to the shape of the inner peripheral surface 19 of the core body 21. That is, the core side surface covering portion 66 has two first side surface covering portions 66a extending from the circumferential center C3 between circumferentially adjacent tooth covering portions 64 toward the tooth covering portions 64, and two second side surface covering portions 66b extending further from the first side surface covering portions 66a toward the tooth covering portions 64 and connected to the tooth covering portions 64.

[0036] The angle θ3 between the two first side surface covering portions 66a is the same as the angle θ1 between the two first circumferential surfaces 19a. The angle θ4 between the first side surface covering portion 66a and the second side surface covering portion 66b is the same as the angle θ2 between the first circumferential surface 19a and the second circumferential surface 19b. In other words, the angle θ3 between the two first side surface covering portions 66a is greater than the angle θ4 between the first side surface covering portion 66a and the second side surface covering portion 66b. Furthermore, the connection portion 66c between the first side surface covering portion 66a and the second side surface covering portion 66b is parallel to the circumferential side surface 28b of the tooth main body 28 and is located on a straight line S passing through the circumferential end portion 73a of the flange side surface covering portion 73 described later.

[0037] The outer wall portion 67 is disposed near the outer peripheral edge of the first core end surface covering portion 65. The outer peripheral cover portion 88b of the terminal holder 85 is disposed radially outward of the outer wall portion 67. The outer wall portion 67 is formed with a lead-in slit 68 and an extraction slit 69 at positions corresponding to each of the tooth covering portions 64 . The draw-in slit 68 is for drawing the coil 24 from the radially outer side to the radially inner side of the outer wall portion 67. The draw-out slit 69 is for drawing the coil 24 from the radially inner side to the radially outer side of the outer wall portion 67.

[0038] The first core end face covering portion 65 and the outer wall portion 67 have a coil pull-out portion 77 integrally molded at the base of a tooth covering portion 64A (hereinafter, this tooth covering portion 64A will be referred to as the specific tooth covering portion 64A) that covers a specific tooth 22A (see Figure 4, hereinafter, this tooth 22A will be referred to as the specific tooth 22A) among the multiple teeth 22. The coil lead-out portion 77 is a portion where the terminal portion 24a (see FIGS. 3 and 4) of the coil 24 of each phase is led upward. The terminal holder 85 is arranged so that the cutout portion 88c of the terminal holder 85 fits into the coil lead-out portion 77. In other words, the terminal 86 of the terminal holder 85 is arranged directly above the coil lead-out portion 77.

[0039] The coil lead-out portion 77 is formed with a plurality of coil guide recesses 78 (for example, three, since the coil 24 in the first embodiment has a three-phase structure) that separately regulate the lead-out locations of the terminal portions 24a of the coils 24 of each phase. These coil guide recesses 78 are arranged in a concentrated manner lined up in the circumferential direction. Each coil guide recess 78 is integrally formed with a coil holding claw 78a that protrudes along the circumferential direction. The terminal portions 24a of the coils 24 of each phase are separately led upward through each coil guide recess 78. The led-out terminal portions 24a of the coils 24 of each phase are guided to terminals 86 of a terminal holder 85 while being held by the coil holding claws 78a, and connected to these terminals 86.

[0040] The tooth covering portion 64 has a radially long tooth end surface covering portion 71 extending from the first core end surface covering portion 65 along the surface direction of this first core end surface covering portion 65, a tooth side surface covering portion 72 protruding downward from both circumferential sides (both short-side ends) of the tooth end surface covering portion 71, a flange side surface covering portion 73 protruding circumferentially outward from the radially inner end of the tooth side surface covering portion 72, and an inner wall portion 74 joined to the radially inner end of the tooth end surface covering portion 71 and the upper end of the flange side surface covering portion 73 and extending upward from the upper end of the flange side surface covering portion 73.

[0041] The tooth end surface covering portion 71 covers the upper end of the tooth main body 28. The tooth side surface covering portion 72 covers the circumferential side surface of the tooth main body 28 of the tooth 22. The two tooth side surface covering portions 72 are parallel to each other and correspond to the circumferential side surface 28b of the tooth main body 28. The second side surface covering portion 66b is connected to the radially outer ends of these tooth side surface covering portions 72. The two tooth side surface covering portions 72 consist of a long tooth side surface covering portion 72a, which has the longest axial length, and a short tooth side surface covering portion 72b, which has the longest axial length of its shortest axial length shorter than that of the long tooth side surface covering portion 72a. In the following description, the length of the longest axial portion of each tooth side surface covering portion 72a, 72b will simply be referred to as the axial length of each tooth side surface covering portion 72a, 72b. The flange side surface covering portion 73 covers the outer peripheral surface of the flange portion 29 of the tooth 22 .

[0042] These tooth side surface covering portions 72 (long tooth side surface covering portions 72a, short tooth side surface covering portions 72b) and flange side surface covering portions 73 are formed continuously with the core side surface covering portion 66 of the core body covering portion 63, forming a cylindrical first skirt portion 79 that protrudes downward from the tooth end surface covering portions 71 and the first core end surface covering portion 65. In other words, the first skirt portion 79 is interposed in the slot 27 of the stator core 20.

[0043] The tip end 79a, which is the lower end of the first skirt portion 79, i.e., the tip end 66d of the core side surface covering portion 66, is formed at an angle so as to smoothly connect the tip end of the long tooth side surface covering portion 72a and the tip end of the short tooth side surface covering portion 72b. That is, the tip end 79a of the first skirt portion 79 (the tip end 66d of the core side surface covering portion 66) is formed at an angle so that the protruding height from the tooth end surface covering portion 71 and the first core end surface covering portion 65 gradually changes along the circumferential direction. By forming the tip end 79 at an angle, when the first insulator 61 is attached to the stator core 20, the first skirt portion 79 is gradually inserted into each tooth 22. This improves the insertability (attachability) of the first insulator 61 into the stator core 20 (teeth 22).

[0044] Of the outer surface 79b of the first skirt portion 79 (the side surfaces of the tooth side surface covering portion 72, the flange side surface covering portion 73, and the core side surface covering portion 66 facing the stator core 20), a pair of press-fit protrusions 82a, 82b is formed on the core side surface covering portion 66 closer to the tooth side surface covering portion 72. The pair of press-fit protrusions 82a, 82b are arranged on both circumferential sides of the tooth covering portion 64. These press-fit protrusions 82a, 82b are used to press-fit and attach the first insulator 61 when attaching it to the stator core 20. The press-fit protrusions 82a, 82b can prevent the first insulator 61 from falling off from the stator core 20.

[0045] The pair of press-fit protrusions 82a, 82b are arranged at equal intervals in the circumferential direction, except for the location corresponding to the specific tooth 22A, every other tooth covering portion 64. In the first embodiment, since there are six teeth 22 (tooth covering portions 64), the pair of press-fit protrusions 82a, 82b are arranged at locations corresponding to three tooth covering portions 64 arranged at equal intervals in the circumferential direction, excluding the specific tooth covering portion 64A.

[0046] In such a first insulator 61, an injection gate mark G is formed on the inner circumferential surface of each inner wall portion 74. The injection gate mark G is a resin injection mark formed when the first insulator 61 is injection molded.

[0047] Next, the second insulator 62 will be described with reference to FIG. 5 and based on FIGS. FIG. 8 is a perspective view of the second insulator 62 of the insulator 26 as viewed from below. 6 and 8, the second insulator 62 has a configuration that is substantially line-symmetrical to the first insulator 61 with respect to the axial center (vertical center) of the stator core 20. Thus, the basic configuration of the second insulator 62 is substantially the same as that of the first insulator 61. For this reason, in the following description, the components of the second insulator 62 that are the same as those of the first insulator 61 will be given the same names and reference numerals as those of the first insulator 61, and description thereof will be omitted. Furthermore, although the second insulator 62 has the same configuration as the first insulator 61, in describing the differences from the first insulator 61, for ease of understanding, the components will basically be given the same names and reference numerals.

[0048] That is, the second insulator 62 is formed by integrally molding a core body covering portion 63 that covers the core body 21 and tooth covering portions 264 that cover the teeth 22. The core body covering portion 63 has an annular second core end face covering portion 265 that covers the other axial end face (an example of the second end face in the claims) 21b of the core body 21, a core side face covering portion 66 that protrudes upward from a contact surface 265a of the second core end face covering portion 265 with the core body 21, and a cylindrical outer wall portion 83 that protrudes downward from the contact surface 265a of the second core end face covering portion 265.

[0049] The difference between the first insulator 61 and the second insulator 62 is that the first core end face covering portion 65 and the outer wall portion 67 of the first insulator 61 have a coil lead-out portion 77 formed therein, whereas the second core end face covering portion 265 and the outer wall portion 83 of the second insulator 62 do not have a coil lead-out portion 77 formed therein. That is, the second core end surface covering portion 265 and the outer wall portion 83 have a simpler structure than the first core end surface covering portion 65 and the outer wall portion 67 of the first insulator 61, and have a uniform shape all around.

[0050] Furthermore, the second skirt portion 279 of the second insulator 62 is made up of the tooth side surface covering portions 72 (long tooth side surface covering portions 72a, short tooth side surface covering portions 72b), the flange side surface covering portions 73, and the core side surface covering portion 66 of the core body covering portion 63. The tip end 279a of the second skirt portion 279 is formed to follow the inclination direction of the tip end 79a of the first skirt portion 79 of the first insulator 61. Therefore, when the first insulator 61 and the second insulator 62 are attached to both axial sides of the stator core 20, the width of the gap O (see FIG. 6) between the tip end 79a of the first skirt portion 79 and the tip end 279a of the second skirt portion 279, which are abutted against each other, is constant.

[0051] The injection gate mark G of the second insulator 62 is similar to that of the first insulator 61. That is, the injection gate mark G is formed on the inner circumferential surface of each inner wall portion 74 of the second insulator 62.

[0052] The insulator 26 (first insulator 61, second insulator 62) configured in this manner forms a coil accommodating recess 70 by the second side surface covering portion 66b of the core side surface covering portion 66, the tooth side surface covering portion 72 (long tooth side surface covering portion 72a, short tooth side surface covering portion 72b), and the flange side surface covering portion 73. The coil 24 wound around each tooth 22 from above the insulator 26 is generally accommodated in the coil accommodating recess 70 (see also FIG. 4).

[0053] Here, the length of the longest axial portion of second skirt portion 279 is longer than the length of the longest axial portion of first skirt portion 79. The longest axial portions of first skirt portion 79 and second skirt portion 279 are each long tooth side surface covering portion 72a. That is, when the axial length of long tooth side surface covering portion 72a of first skirt portion 79 is L1 and the axial length of long tooth side surface covering portion 72a of second skirt portion 279 is L2, lengths L1 and L2 are L2>L1 (1) In the following description, the length of the longest part of the first skirt portion 79 in the axial direction will be simply referred to as the length L1 of the first skirt portion 79. The length of the longest part of the second skirt portion 279 in the axial direction will be simply referred to as the length L2 of the second skirt portion 279.

[0054] Furthermore, the length L1 of the first skirt portion 79 and the length L2 of the second skirt portion 279 are L2 ≥ 1.7 × L1 (2) It is desirable to satisfy the following. The actions and effects of the above formulas (1) and (2) will be described in detail below.

[0055] A mold (not shown) is used, and molten resin is poured into the mold through a gate (not shown) to form the first insulator 61 and the second insulator 62. These insulators 61, 62 undergo slight deformation due to shrinkage caused by resin contraction during hardening. Due to their structure, the skirt portions 79, 279 extending from the core end surface covering portions 65, 265 of the insulators 61, 62 undergo large deformation.

[0056] Here, the first insulator 61 has a coil lead-out portion 77, whereas the second insulator 62 does not. The shape of the first insulator 61 is complex and non-uniform over the entire circumference due to the presence of the coil lead-out portion 77. In contrast, the shape of the second insulator 62 is simple and uniform over the entire circumference. For this reason, the deformation amount of each first skirt portion 79 of the first insulator 61 is likely to be non-uniform, and the deformation amount itself is large. In contrast, the deformation amount of each second skirt portion 279 of the second insulator 62 is uniform, and the deformation amount itself can be kept small. A uniform deformation amount means that the direction of deformation is also uniform.

[0057] That is, for example, if the length L1 of the first skirt portion 79 and the length L2 of the second skirt portion 279 are the same (hereinafter, such a case will be referred to as a conventional product), not only will the amount of deformation of the first skirt portion 79 be uneven relative to the amount of deformation of the second skirt portion 279, but the amount of deformation will be greater. Therefore, by making the length L1 of the first skirt portion 79 and the length L2 of the second skirt portion 279 satisfy the above formula (2), the amount of deformation of the second insulator 62 will reliably be greater than the amount of deformation of the first insulator 61.

[0058] Figure 9 is a graph showing the change in deformation ratio when the vertical axis represents the deformation ratio obtained by dividing the deformation amount of the second insulator 62 by the deformation amount of the first insulator 61, and the horizontal axis represents the skirt length ratio obtained by dividing the length L2 of the second skirt portion 279 by the length L1 of the first skirt portion 79. 9, it can be confirmed that when the above formula (2) is satisfied, the deformation ratio is equal to or greater than 1. That is, the deformation amount of the second insulator 62 is greater than the deformation amount of the first insulator 61.

[0059] As described above, the second skirt portions 279 of the second insulator 62 are uniformly deformed. Therefore, even if the deformation amount of the second insulator 62 is made larger than the deformation amount of the first insulator 61, the ease of assembly of the second insulator 62 to the stator core 20 is improved compared to when the deformation amount of the first insulator 61 is larger. As a result, the ease of assembly of the entire insulator 26 can be improved.

[0060] Fig. 10 is a graph comparing the amount of deformation of each insulator 61, 62 between a conventional product and the first embodiment. The amount of deformation shown in Fig. 10 refers to the maximum amount of deformation. That is, in each insulator 61, 62, the portion with the largest amount of deformation is each skirt portion 79, 279, so the amount of deformation shown in Fig. 10 refers to the amount of deformation at the portion of each skirt portion 79, 279 with the largest amount of deformation.

[0061] As shown in Fig. 10, it can be seen that in the conventional product, the deformation amount of the first insulator 61 is significantly larger than that of the second insulator 62. Since the deformation amounts of the first skirt portions 79 of the first insulator 61 are non-uniform, the assemblability of the first insulator 61 to the stator core 20 deteriorates. Note that the lengths L1 and L2 in the first embodiment shown in Fig. 10 satisfy L2 = 2.1 × L1.

[0062] Therefore, according to the first embodiment described above, when the coil lead-out portion 77 is formed only on the first core end face covering portion 65 (outer wall portion 67) of the first insulator 61, the length L2 of the second skirt portion 279 in the second insulator 62 in which this coil lead-out portion 77 is not formed satisfies the above formula (1), thereby improving the assembly ease of the insulator 26 compared to conventional products. Furthermore, the amount of deformation of the insulator 26 can be reduced as a result compared to conventional products (see the graph of the first embodiment in FIG. 10), and therefore the molding precision of the insulator 26 can be improved.

[0063] Furthermore, by having the length L2 of the second skirt portion 279 of the second insulator 62 satisfy the above formula (2), the deformation amount of the second insulator 62 can be made equal to or greater than the deformation amount of the first insulator 61. This ensures improved assembly and molding accuracy of the insulator 26. Furthermore, by setting the lengths L1 and L2 to satisfy L2≦8.2×L1, it is possible to ensure that the length of the first skirt portion 79 is long enough to accommodate the press-fit protrusions 82a and 82b.

[0064] In the insulator 26 (first insulator 61, second insulator 62) as described above, an injection gate mark G is formed on the inner circumferential surface of each inner wall portion 74. In other words, the injection gate mark G is formed at a position that avoids each skirt portion 79, 279. That is, each skirt portion 79, 279 is located at the most downstream side in the direction of resin flow during injection molding. In such a configuration of the insulator 26, the configuration of the first embodiment described above can be suitably used.

[0065] Since the molding precision of the insulator 26 (first insulator 61, second insulator 62) can be improved, it will be possible to contribute to Goal 12 of the United Nations-led Sustainable Development Goals (SDGs), which is to "Ensure sustainable consumption and production patterns."

[0066] [Second embodiment] <Second insulator> Next, a second embodiment will be described with reference to Figures 11 and 12, with reference to Figure 3. The same features as those in the first embodiment described above will be assigned the same reference numerals, and a description thereof will be omitted. Fig. 11 is a perspective view of the second insulator 262 in the second embodiment as seen from above. Fig. 12 is a partially enlarged plan view of the stator core 20 with the second insulator 262 attached thereto as seen from the axial direction.

[0067] 3, 11, and 12, the stator 8 in the second embodiment is similar to that in the first embodiment in that it includes a cylindrical stator core 20 whose central axis coincides with the rotation axis C1, an insulator 26 attached to the stator core 20, and a plurality of coils 24 having a three-phase (U-phase, V-phase, W-phase) structure wound around the insulator 26 from above the stator core 20. The basic configurations of the first insulator 61 and the second insulator 262 in the second embodiment are similar to the basic configurations of the first insulator 61 and the second insulator 62 in the first embodiment. The length L2 of the second skirt portion 279 of the second insulator 262 satisfies the above formula (1), and preferably satisfies the above formula (2), similar to that in the first embodiment.

[0068] The difference between the first and second embodiments is that the shape of the second insulator 62 in the first embodiment is different from the shape of the second insulator 262 in the second embodiment.

[0069] Here, we will explain the flow of resin when forming each insulator 61, 262. First, the resin flows from the radially inner side to the radially outer side, as indicated by the injection gate marks G formed on the inner circumferential surface of each inner wall portion 74. Next, the resin reaches the base of each skirt portion 79, 279 (on the side of each core end surface covering portion 65, 265), and then flows toward the tip portions 79a, 279a.

[0070] In such injection molding, if the length L2 of the second skirt portion 279 satisfies the above formula (1), the longer the length of the second skirt portion 279, the worse the flow of the resin into the second skirt portion 279. Therefore, the second skirt portion 279 was formed as follows.

[0071] First, in the second skirt portion 279 of the second insulator 262, when the thickness of the core side surface covering portion 66 is T1, the thickness of the long tooth side surface covering portion 72a of the tooth side surface covering portion 72 is T2, and the thickness of the short tooth side surface covering portion 72b is T3, the thicknesses T1 to T3 are as follows: T1>T2>T3 (3) Meet the following.

[0072] The reason for the above formula (3) is as follows. Specifically, to improve the ease of insertion (attachment) of second insulator 62 into stator core 20, long teeth side surface covering portion 72a and short teeth side surface covering portion 72b are provided with different lengths. As a result, the speed at which resin is filled into long teeth side surface covering portion 72a, which is longer, is reduced, so T2 > T3 is set. As a result of increasing thickness T2 of long teeth side surface covering portion 72a, the speed at which resin is filled into core side surface covering portion 66 is reduced, so T1 > T2 is set. In this way, by making each thickness T1 to T3 satisfy the above formula (3), resin can be distributed evenly throughout each portion.

[0073] Next, in the second skirt portion 279 of the second insulator 262, of the two connecting portions 66c of the core side surface covering portion 66, a thick portion 91 is formed in the connecting portion 66c closer to the short tooth side surface covering portion 72b, the thick portion 91 being thicker than the other portions of the core side surface covering portion 66. In other words, the thick portion 91 is formed closer to the short tooth side surface covering portion 72b than the circumferential center of the core side surface covering portion 66. The thick portion 91 extends over the entire axial direction of the core side surface covering portion 66.

[0074] The reason for forming the thick portion 91 is as follows. That is, in the configuration of the second skirt portion 279 described above, by increasing the thickness T1 of the core side surface covering portion 66, the resin filling speed at the connecting portion 66c closer to the short tooth side surface covering portion 72b of the two connecting portions 66c of the core side surface covering portion 66 is reduced. Therefore, by forming the thick portion 91 at the connecting portion 66c closer to the short tooth side surface covering portion 72b of the two connecting portions 66c of the core side surface covering portion 66, the flow path of this connecting portion 66c can be made sufficiently large. Therefore, the resin filling speed at the connecting portion 66c can be sufficiently ensured.

[0075] Next, a recess 92 is formed in the tip end 279a of the second skirt portion 279, spanning across the two first side surface covering portions 66a. The recess 92 is formed to be recessed further toward the second core end surface covering portion 265 than the tip end 279a of the second skirt portion 279. A length L3 from the second core end surface covering portion 265 to the bottom surface 92a of the recess 92 is substantially the same as the axial length of the short tooth side surface covering portion 72b.

[0076] Both circumferential side surfaces 92b of the recess 92 are inclined so that the circumferential width of the recess 92 gradually increases toward the tip end 279a. The formation of the recess 92 shortens the length (length L3) of the first side surface covering portion 66a from the second core end surface covering portion 265 at the location where the recess 92 is formed, thereby reducing the volume of the second skirt portion 279. This makes it possible to prevent short shots from occurring in the second skirt portion 279 during injection molding of the second insulator 262. Furthermore, because both circumferential side surfaces 92b of the recess 92 are inclined, resin flows smoothly through the recess 92 toward the tip end 279a of the second skirt portion 279.

[0077] 12, the coil 24 wound around each tooth 22 from above the insulators 26 (first insulator 61, second insulator 262) is generally housed in the coil accommodating recess 70 (see also FIG. 4). The position of the thick-walled portion 91 formed in the second insulator 262 is the position of the connecting portion 66c, which is the circumferential end of the coil accommodating recess 70. Therefore, the thick-walled portion 91 hardly affects the space factor of the coil 24. Furthermore, by forming the recess 92, the inner circumferential surface 19 of the core body 21 is exposed through the area where the recess 92 is formed. However, the recess 92 is formed in the first side surface covering portion 66a, which does not constitute the coil storage recess 70. In other words, the amount of coil 24 stacked in the first side surface covering portion 66a is small. Therefore, by forming the recess 92, it is possible to prevent the insulation between the stator core 20 and the coil 24 from being impaired.

[0078] As described above, in the second embodiment, in the second skirt portion 279 of the second insulator 262, the thickness T1 of the core side surface covering portion 66, the thickness T2 of the long tooth side surface covering portion 72a of the tooth side surface covering portion 72, and the thickness T3 of the short tooth side surface covering portion 72b satisfy the above formula (3). That is, the thickness T1 of the core side surface covering portion 66 is thicker than the thicknesses T2 and T3 of the tooth side surface covering portion 72. Therefore, even if the length L2 of the second skirt portion 279 is longer than the length L1 of the first skirt portion 79, the flow of molten metal in the second skirt portion 279 can be improved. Therefore, in addition to the same effects as the first embodiment, the molding accuracy of the second insulator 262 (insulator 26) can be further improved.

[0079] Furthermore, by making thickness T2 of long tooth side surface covering portion 72a thicker than thickness T3 of short tooth side surface covering portion 72b, the flow of resin in second skirt portion 279 can be further improved.

[0080] A thick portion 91 is formed closer to the short tooth side surface covering portion 72b than the circumferential center of the core side surface covering portion 66. The thick portion 91 extends over the entire axial direction of the core side surface covering portion 66. By forming the thick portion 91 in this manner, it is possible to prevent short shots in the second skirt portion 279 during injection molding. More specifically, of the two connecting portions 66c of the core side surface covering portion 66, the thick portion 91 is formed in the connecting portion 66c closer to the short tooth side surface covering portion 72b. This prevents the occurrence of a portion where the resin filling speed in the second skirt portion 279 decreases. This prevents short shots in the second skirt portion 279 during injection molding, further improving the molding precision of the second insulator 262 (insulator 26).

[0081] A recess 92 is formed in the tip end 279a of the second skirt portion 279 so as to be recessed further toward the second core end face covering portion 265 than the tip end 279a. This makes it possible to shorten the length (length L3) of the first side surface covering portion 66a from the second core end face covering portion 265 at the location where this recess 92 is formed, thereby reducing the volume of the second skirt portion 279. This makes it possible to prevent short shots from occurring in the second skirt portion 279 during injection molding of the second insulator 262.

[0082] Moreover, the recesses 92 are formed in the core side surface covering portion 66 (the two first side surface covering portions 66a). Because the amount of coil 24 stacked on the core side surface covering portion 66 is small, forming the recesses 92 can prevent insulation between the stator core 20 and the coil 24 from being impaired, and can also prevent the function of the insulator 26 from being impaired. Furthermore, since both circumferential side surfaces 92b of the recess 92 are formed to be inclined, the resin flows smoothly through the recess 92 toward the tip end 279a of the second skirt portion 279. This further improves the molding precision of the second insulator 262 (insulator 26).

[0083] Furthermore, improving the molding precision of the second insulator 262 does not affect the space factor of the coil 24, thereby improving the torque performance of the electric motor 2. This reduces the energy consumption when driving the electric motor 2. This makes it possible to contribute to Goal 7 of the United Nations-led Sustainable Development Goals (SDGs) to "Ensure access to affordable, reliable, sustainable and modern energy for all."

[0084] The present invention is not limited to the above-described embodiment, but includes various modifications to the above-described embodiment without departing from the spirit of the present invention. For example, in the above embodiment, the reduction geared motor 1 is described as being used as a drive source for a wiper device of a vehicle. However, this is not a limitation, and the reduction geared motor 1 can be applied to various drive devices. Furthermore, only the electric motor 2 having the above-described configuration of the reduction geared motor 1 may be used in various electrical devices.

[0085] In the above embodiment, the coil 24 of the stator 8 has a three-phase (U-phase, V-phase, W-phase) structure. However, the number of phases of the coil 24 is not limited to three.

[0086] In the above embodiment, the stator core 20 has been described as including a cylindrical core body 21 and a plurality of (six) teeth 22 protruding radially inward from the inner circumferential surface 19 of the core body 21. The rotor 9 is disposed radially inside the stator 8 having such a stator core 20. However, this is not limited to this, and the stator core 20 may have a configuration in which the teeth 22 protrude radially outward from the outer circumferential surface of the core body 21. The rotor 9 may be disposed radially outside the stator 8 having such a stator core 20. The number of teeth 22 is not limited to six. The insulator 26 may be formed to correspond to the shape of the stator core 20. The above configuration can also be adopted for such an insulator 26. [Explanation of symbols]

[0087] 1...motor with reducer, 2...electric motor, 3...reduction section, 4...controller, 5...motor case, 6...first motor case, 6a...opening, 7...second motor case, 7a...opening, 8...stator, 9...rotor, 10...bottom, 10a...through hole, 11...connector, 16...outer flange section, 17...outer flange section, 19...inner circumferential surface (circumferential surface), 19a...first circumferential surface, 19b...second circumferential surface, 20...stator core, 20p...electromagnetic steel sheet, 21...core body, 21a...one axial end face (an example of a first end face), 21b...other axial end face (an example of a second end face), 22...teeth, 23...fixing section, 23 a...bolt insertion hole, 24...coil, 24a...terminal portion, 25...bolt, 26...insulator, 27...slot, 28...teeth main body, 28a...teeth tip portion, 28b...circumferential side surface, 29...flange portion, 31...shaft, 32...rotor core, 32a...magnet cover, 40...gear case, 40a...opening, 40b...side wall, 40c...bottom wall, 41...worm reduction mechanism, 42...gear accommodating portion, 43...opening, 44...worm shaft, 45...worm wheel, 46...bearing, 47...bearing, 48...output shaft, 48a...spline, 49...bearing boss, 50...magnetic detection element, 51 ...controller board, 52...rib, 53...cover, 61...first insulator, 62...second insulator, 63...core body covering portion, 64...teeth covering portion, 64A...specific tooth covering portion, 65...first core end face covering portion, 65a...abutment surface, 66...core side face covering portion, 66a...first side face covering portion, 66b...second side face covering portion, 66c...connection portion, 66d...tip portion, 67...outer wall portion, 68...pull-in slit, 69...pull-out slit, 70...coil storage recess, 71...teeth end face covering portion, 72...teeth side face covering portion, 72a...long tooth side face covering portion, 72b...short Tooth side surface covering portion, 73... flange side surface covering portion, 73a... circumferential end portion, 74... inner wall portion, 77... coil lead-out portion, 78... coil guide recessed portion, 78a... coil holding claw, 79... first skirt portion, 79a... tip portion, 79b... outer surface, 82a... press-fit convex portion, 82b... press-fit convex portion, 83... outer wall portion, 85... terminal holder, 86... terminal, 87... holder body, 87a... terminal accommodating recessed portion, 88... cover portion, 88a... end face cover portion, 88b... outer periphery cover portion, 88c... cut-out portion, 91... thick portion, 92... recessed portion, 92a... bottom surface, 92b... side surface, 262... second insulator, 264... tooth covering portion,265...second core end surface covering portion, 265a...abutment surface, 279...second skirt portion, 279a...tip portion, C1...rotation axis, C2...circumferential center, C3...circumferential center, G...injection gate mark, O...gap, S...straight line, T1...wall thickness, T2...wall thickness, T3...wall thickness, θ1...angle, θ2...angle, θ3...angle, θ4...angle,

Claims

1. A resin insulator that is attached to a stator core having an annular core body and a plurality of teeth protruding from the core body in a radial direction, and that provides insulation between the stator core and coils wound around the teeth, a first insulator and a second insulator attached to both axial sides of the stator core, The first insulator is a first core end surface covering portion covering a first axial end surface of the core body; a first skirt portion extending in the axial direction from the first core end surface covering portion toward the second insulator and covering a circumferential surface of the core body and circumferential side surfaces of the teeth; Has, The second insulator is a second core end surface covering portion covering a second end surface of the core body opposite to the first end surface in the axial direction; a second skirt portion extending in the axial direction from the second core end surface covering portion toward the first insulator and covering the circumferential surface of the core body and the circumferential side surfaces of the teeth; and The second skirt portion is a core side surface covering portion that covers the circumferential surface of the core body; a recess formed at a tip end of the core side surface covering portion opposite to the second core end surface covering portion, the recess being recessed toward the second core end surface covering portion from the tip end; and a coil lead-out portion that is integrally provided only on the first core end surface covering portion and that leads an end portion of the coil out from the first insulator to the outside, When the length of the longest part in the axial direction of the second skirt portion is L2 and the length of the longest part in the axial direction of the first skirt portion is L1, the length L1 and the length L2 are L2≧1.7×L1 fulfill An insulator characterized by:

2. The second skirt portion is two tooth side surface covering portions that respectively cover both circumferential side surfaces of tooth bodies that extend along the radial direction of the teeth; a flange side covering portion that is integrally formed with a tip portion of the tooth body on the radially opposite side of the core body and covers an outer peripheral surface of a flange portion extending in a circumferential direction; and The insulator according to claim 1 , wherein the thickness of the core side surface covering portion is greater than the thickness of the tooth side surface covering portion.

3. The two tooth side surface covering portions are a long tooth side covering portion having a longest length in the axial direction; a short tooth side surface covering portion having a length at its longest point in the axial direction shorter than that of the long tooth side surface covering portion; Including, the core side surface covering portion has a thick portion formed closer to the short teeth side surface covering portion than the circumferential center, the thick portion being thicker than the thickness of other portions of the core side surface covering portion, 3. The insulator according to claim 2, wherein the thick portion extends over the entire axial direction of the core side surface covering portion.

4. the two tooth side surface covering portions extend radially inward from the core side surface covering portion, The core side surface covering portion is two first side surface covering portions extending from a center between adjacent tooth side surface covering portions toward the tooth side surface covering portions; a second side surface covering portion extending further from the first side surface covering portion toward the tooth side surface covering portion and connected to the tooth side surface covering portion; and a connection portion between the first side surface covering portion and the second side surface covering portion is located on a straight line that is parallel to the circumferential side surface of the tooth main body and passes through a circumferential end portion of the flange side surface covering portion, 4. The insulator according to claim 3, wherein the thick portion is formed at an end of the first side surface covering portion on the second side surface covering portion side.

5. 5. The insulator according to claim 3, wherein the thickness of the long teeth side surface covering portion is greater than the thickness of the short teeth side surface covering portion.

6. The core side surface covering portion is two first side surface covering portions extending from a center between adjacent tooth side surface covering portions toward the tooth side surface covering portions; a second side surface covering portion extending further from the first side surface covering portion toward the tooth side surface covering portion and connected to the tooth side surface covering portion; and a connection portion between the first side surface covering portion and the second side surface covering portion is located on a straight line that is parallel to the circumferential side surface of the tooth main body and passes through a circumferential end portion of the flange side surface covering portion, The recess is formed in the first side surface covering portion. The insulator according to any one of claims 2 to 5.

7. The circumferential side surface of the recess is inclined so that the circumferential width of the recess gradually increases toward the tip end. The insulator according to any one of claims 1 to 6.

8. A gate mark formed by injecting resin during molding is provided at a position that avoids the first skirt portion and the second skirt portion. The insulator according to any one of claims 1 to 7.

9. The insulator according to any one of claims 1 to 8; a stator core having an annular core body to which the insulator is attached and teeth protruding radially from a circumferential surface of the core body; a coil wound around the tooth via the insulator. A stator characterized by:

10. A stator according to claim 9; a rotor rotatably provided relative to the stator; An electric motor characterized by:

Images