Brushless motor

Abstract

To provide a brushless motor that is suppressed in increases of manufacturing cost, is suppressed in dispersion of winding resistance of a coil without deteriorating the moldability of an insulator, and can be improved in motor performance.SOLUTION: An insulator 40 has a winding drum covering portion 42 that covers the surrounding of a winding drum portion and a flange covering portion 43 that covers the outer peripheral surface of a flange portion 32. When the intersection of a straight line passing through a rotational axis and an end part in the circumferential direction, of a flange portion and a back yoke is defined as P, the length between the intersection P and the rotational axis is defined as L, the shorter of the two lengths of the long-side teeth is defined as Ll, and the shorter of the two lengths of the short-side teeth is defined as Ls, at the end part in the direction of the rotational axis, of the winding drum covering portion 42 having the longer length among the Ll and the Ls, a thick-walled portion 47 is provided, which is thicker than the end portion in the direction of the rotational axis, of the winding drum covering portion having the shorter length.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a brushless motor. [Background technology]

[0002] For example, an inner rotor type brushless motor includes an annular stator and a rotor rotatably mounted in the radial center of the stator. The stator includes a stator core, an insulator attached to the stator core, and a coil wound around the stator core from above the insulator. The stator core includes an annular back yoke and a plurality of teeth protruding radially inward from the inner circumferential surface of the back yoke. A coil is wound around each tooth from above the insulator.

[0003] The rotor includes a rotor shaft that rotates around a rotation axis, a cylindrical rotor core fixed to the rotor shaft, and permanent magnets attached to the outer periphery of the rotor core. With this configuration, when current is sequentially supplied to specific coils, a specific magnetic flux linkage is formed in each tooth. This magnetic flux linkage acts as a magnetomotive force, generating magnetic attractive and repulsive forces between the permanent magnets and the rotor. This allows the rotor to rotate continuously.

[0004] However, there are cases where such brushless motors are made smaller by, for example, flattening them. As a means for flattening brushless motors, a technique for flattening the stator core has been disclosed (see, for example, Patent Document 1). In this device, the back yoke is composed of two linear yokes and two arc-shaped yokes. The linear yokes and arc-shaped yokes are arranged alternately in the circumferential direction. Teeth protrude from each yoke.

[0005] Because the distance from the axis of rotation to each yoke is different, the nozzle of the winding device used to wind the coil can penetrate a shorter distance on teeth protruding from a linear yoke than on teeth protruding from an arc-shaped yoke. Coils wound around teeth with a shorter nozzle penetration distance are more likely to become thicker than coils wound around teeth with a longer nozzle penetration distance. Coils that become thicker have a longer circumference when wound around a tooth, resulting in higher winding resistance.

[0006] In this way, to prevent variations in the coil winding resistance for each tooth, the teeth protruding from the arc-shaped yoke are provided with insulators and the coils are wound around them. This configuration artificially shortens the length of the teeth with the insulator, making the length of the teeth protruding from the arc-shaped yoke approximately the same as the length of the teeth protruding from the linear yoke. This reduces variations in the size of the space (hereinafter referred to as the winding area) that is formed between adjacent teeth in the circumferential direction and can accommodate the coil. This also reduces variations in the coil winding resistance for each tooth. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-195377 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the above-described embodiment, the winding area of the teeth protruding from the arc-shaped yoke becomes extremely small, resulting in a problem that it is difficult to improve motor performance. Furthermore, the provision of the insulating material not only increases the manufacturing cost, but also causes problems such as deterioration of the moldability of the insulator when, for example, the insulating material is provided integrally with the insulator.

[0009] Therefore, the present invention provides a brushless motor that can suppress increases in manufacturing costs, suppress variations in the winding resistance of the coil without deteriorating the formability of the insulator, and improve motor performance. [Means for solving the problem]

[0010] In order to solve the above problems, in a first aspect of the present invention, there is provided a rotor including an annular stator and a rotor disposed radially inside the stator and rotatable relative to the stator, the stator including a stator core, an insulator covering the periphery of the stator core, and a coil wound around the stator core from above the insulator, the stator core having a flat shape when viewed from a direction of a rotation axis of the rotor and including an annular back yoke and a plurality of teeth protruding radially inward from an inner circumferential surface of the back yoke and around which the coil is wound, the back yoke having a pair of first side portions disposed opposite each other across the rotation axis and a pair of second side portions disposed opposite each other in a direction perpendicular to the opposing direction of the first side portions, and each of the teeth protruding from the inner circumferential surface of the back yoke and including a winding drum portion around which the coil is wound and a pair of teeth of the winding drum portion and a flange portion provided at an end opposite to the back yoke and extending in the circumferential direction longer than the circumferential width of the winding drum portion, and each of the teeth has first side teeth provided on the pair of first side portions and second side teeth provided on the pair of second side portions, the insulator has a winding drum covering portion that covers the periphery of the winding drum portion and a flange covering portion that covers the outer peripheral surface of the flange portion, and a line passing through the rotation axis and the circumferential end of the flange portion and a line passing through the back When the intersection point between the yoke and the yoke is defined as P, the length between the intersection point P and the rotation axis is defined as L, the shorter of the two lengths L for the first side tooth is defined as Ll, and the shorter of the two lengths L for the second side tooth is defined as Ls, the end of the longer of the lengths Ll and Ls in the direction of the rotation axis of the winding drum covering portion has a thick portion that is thicker than the end of the shorter of the winding drum covering portion in the direction of the rotation axis.

[0011] This configuration makes it possible to make the circumferential length of the coil wound around each tooth uniform without drastically reducing the winding area of either the first side tooth or the second side tooth, whichever tooth has the longer distance that the nozzle of the winding device can penetrate, thereby suppressing variations in the winding resistance of the coil and improving motor performance. The insulator only needs to have a thickened portion formed at the end of the insulator in the direction of the rotation axis. This makes manufacturing easier than when an insulating portion is provided as in the past, and reduces manufacturing costs. This also prevents deterioration in the moldability of the insulator.

[0012] In a second aspect of the present invention, in the brushless motor of the first aspect, the winding drum portion of either the first side tooth or the second side tooth extends along the radial direction, and the other winding drum portion extends in a direction intersecting the radial direction, and the winding drum covering portion of the winding drum portion extending along the radial direction may have the thick portion.

[0013] Teeth extending in a direction intersecting the radial direction can be made longer than teeth extending radially at the same location. This allows for a larger winding area. On the other hand, the distance the nozzle of the winding device can penetrate is shorter, making the coil more susceptible to thickening and collapse, resulting in higher winding resistance. By providing thickened portions on the radially extending teeth, it is possible to suppress variations in winding resistance throughout the stator core. This allows for the stator core to have a flat shape while maximizing motor performance.

[0014] In a third aspect of the present invention, in the brushless motor of the second aspect, the flange portion has a first flange portion extending from the winding drum portion in a first circumferential direction and a second flange portion extending from the winding drum portion in a second direction circumferentially opposite to the first direction, and the insulator of the tooth having the winding drum portion extending in a direction intersecting the radial direction has a locking portion provided at a connection between the winding drum covering portion and the flange covering portion, and the locking portion locks the coil arranged at a larger angle of a first angle between the winding drum portion and the first flange portion and a second angle between the winding drum portion and the second flange portion. When viewed from the direction of the rotation axis, the coil that is in contact with the flange covering portion is defined as the flanged portion coil, the coil that is locked by the locking portion is defined as the locked portion coil, a line connecting the center of the flanged portion coil and the center of the locked portion coil is defined as a first line, an intersection of the first line and the center line of the winding drum is defined as Q, a line that passes through the intersection Q and is perpendicular to the center line is defined as a second line, and a line that passes through the center of the locked portion coil and is parallel to the second line is defined as a third line, the length between the second line and the third line may be smaller than the diameter of the coil.

[0015] For teeth extending in a direction intersecting the radial direction, the first angle between the winding drum and the first flange and the second angle between the winding drum and the second flange are different. When a coil is wound around such a winding drum, the coil is wound at an extremely oblique angle relative to the winding drum, making the coil prone to collapse. In such cases, the coil's winding resistance varies. Therefore, by configuring as described above, it is possible to prevent the coil from being wound at an extremely oblique angle relative to the winding drum. As a result, the coil's collapse can be prevented and the variation in the coil's winding resistance can be suppressed. This improves motor performance.

[0016] In a fourth aspect of the present invention, a brushless motor includes an annular stator and a rotor disposed radially inside the stator and rotatable relative to the stator, the stator including a stator core, an insulator covering the periphery of the stator core, and a coil wound around the stator core from above the insulator, the stator core having a flat shape when viewed from the direction of a rotation axis of the rotor and including an annular back yoke and a plurality of teeth protruding radially inward from an inner circumferential surface of the back yoke and around which the coil is wound, the back yoke having a pair of first side portions disposed opposite each other across the rotation axis and a pair of second side portions disposed opposite each other in a direction perpendicular to the opposing direction of the first side portions across the rotation axis, the length along the circumferential direction of the second side portions being shorter than the length along the circumferential direction of the first side portions, and each of the teeth being disposed on the inner circumferential surface of the back yoke the insulator has a winding drum portion protruding from the back yoke and around which the coil is wound, and a flange portion provided at the end of the winding drum opposite the back yoke and extending circumferentially longer than the circumferential width of the winding drum, and each of the teeth has first side teeth, two on each of the pair of first side portions, and second side teeth, one on each of the pair of second side portions, the insulator has a winding drum covering portion that covers the periphery of the winding drum, and a flange covering portion that covers the outer peripheral surface of the flange, the winding drum portion of one of the first side teeth and the second side tooth extends along the radial direction, and the other winding drum portion extends in a direction intersecting the radial direction, and an end of the winding drum covering portion in the direction of the rotation axis of the winding drum portion extending along the radial direction is provided with a thick portion that is thicker than an end of the winding drum covering portion in the direction of the rotation axis of the winding drum portion extending in the direction intersecting the radial direction.

[0017] Teeth extending in a direction intersecting the radial direction can be made longer than teeth extending radially at the same location. This makes it easier to ensure a larger winding area. On the other hand, the distance that the nozzle of the winding device can penetrate is shorter, making it easier for the coil to thicken and collapse, resulting in higher winding resistance. By providing thickened portions on the radially extending teeth, it is possible to suppress variations in winding resistance throughout the stator core. This suppresses variations in coil winding resistance and improves motor performance. The insulator only needs to have a thickened portion formed at the end of the insulator in the direction of the rotation axis. This makes manufacturing easier than when an insulating portion is provided as in the past, and reduces manufacturing costs. This also prevents deterioration in the moldability of the insulator.

[0018] In a fifth aspect of the present invention, in the brushless motor of the fourth aspect, the flange portion has a first flange portion extending from the winding drum portion in a first circumferential direction and a second flange portion extending from the winding drum portion in a second direction circumferentially opposite to the first direction, and the insulator of the tooth having the winding drum portion extending in a direction intersecting with the radial direction has a locking portion provided at a connection between the winding drum covering portion and the flange covering portion, and the locking portion locks the coil arranged at a larger angle of a first angle between the winding drum portion and the first flange portion and a second angle between the winding drum portion and the second flange portion. When viewed from the direction of the rotation axis, the coil that is in contact with the flange covering portion is defined as the flanged portion coil, the coil that is locked by the locking portion is defined as the locked portion coil, a line connecting the center of the flanged portion coil and the center of the locked portion coil is defined as a first line, an intersection of the first line and the center line of the winding drum is defined as Q, a line that passes through the intersection Q and is perpendicular to the center line is defined as a second line, and a line that passes through the center of the locked portion coil and is parallel to the second line is defined as a third line, the length between the second line and the third line may be smaller than the diameter of the coil.

[0019] With this configuration, even if the coil is wound at an extremely oblique angle around the winding drum, which would make the coil prone to collapse, the coil can be prevented from being wound at an extremely oblique angle around the winding drum. As a result, the coil can be prevented from collapsing, and variations in the winding resistance of the coil can be suppressed, thereby improving motor performance.

[0020] In a sixth aspect of the present invention, a brushless motor includes an annular stator and a rotor disposed radially inside the stator and rotatable relative to the stator, the stator including a stator core, an insulator surrounding the stator core, and a coil wound around the stator core from above the insulator, the stator core having a flat shape when viewed from the direction of the rotation axis of the rotor, and an annular back yoke and a coil protruding radially inward from an inner peripheral surface of the back yoke, the coil the back yoke has a pair of first side portions disposed opposite to each other across the rotation axis and a pair of second side portions disposed opposite to each other across the rotation axis in a direction perpendicular to the opposing direction of the first side portions, and the second side portions have a circumferential length shorter than a circumferential length of the first side portions, and each of the teeth protrudes from an inner peripheral surface of the back yoke and has a winding drum portion around which the coil is wound, and a flange portion provided at an end of the winding drum opposite to the back yoke and extending in the circumferential direction longer than the circumferential width of the winding drum portion; Each of the teeth includes two first side teeth provided on each of the pair of first side portions and one second side tooth provided on each of the pair of second side portions, the winding trunk portion of one of the first side teeth and the second side teeth extends along a radial direction, and the winding trunk portion of the other extends in a direction intersecting the radial direction, the flange portion includes a first flange portion extending from the winding trunk portion in a first circumferential direction, and a second flange portion extending from the winding trunk portion in a second direction circumferentially opposite to the first direction, and the insulator is the insulator of the tooth has a winding drum covering portion that covers the periphery of the winding drum portion and a flange covering portion that covers the outer peripheral surface of the flange portion, and the winding drum portion extends in a direction intersecting with the radial direction, and the insulator has a locking portion provided at a connection portion between the winding drum covering portion and the flange covering portion, and the locking portion locks the coil that is arranged at a larger angle of a first angle between the winding drum portion and the first flange portion and a second angle between the winding drum portion and the second flange portion, and the coil that is in contact with the flange covering portion of the coils when viewed from the direction of the rotation axis is a flanged coil,The coil locked by the locking portion is defined as the locked portion coil, a line connecting the center of the flange portion coil and the center of the locked portion coil is defined as a first line, the intersection of the first line and the center line of the winding drum is defined as Q, a line passing through the intersection Q and perpendicular to the center line is defined as a second line, and a line passing through the center of the locked portion coil and parallel to the second line is defined as a third line, the length between the second line and the third line is smaller than the diameter of the coil.

[0021] This configuration allows the winding area to be secured as much as possible even for teeth where it is difficult to secure the winding area, thereby maximizing motor performance while maintaining a flat stator core. Even in cases where the coil is wound at an extremely oblique angle around the winding drum, making the coil prone to collapse, the coil can be prevented from being wound at an extremely oblique angle around the winding drum. As a result, the coil can be prevented from collapsing, and variations in the winding resistance of the coil can be suppressed, thereby improving motor performance.

[0022] To prevent the coil from becoming unwound, it is only necessary to provide a locking portion on the insulator. This makes manufacturing easier than when an insulating portion is provided as in the past, and it is possible to suppress increases in manufacturing costs. It is also possible to prevent deterioration in the formability of the insulator.

[0023] In a seventh aspect of the present invention, in a brushless motor of any one of the third, fifth, or sixth aspects, the locking portion may be formed by making the thickness of the flange covering portion thicker than the thickness of the winding drum covering portion.

[0024] This configuration allows the locking portion to be easily formed, thereby suppressing an increase in the manufacturing cost of the insulator and preventing a deterioration in the moldability of the insulator. [Effects of the Invention]

[0025] According to the present invention, it is possible to suppress increases in the manufacturing costs of brushless motors, to suppress variations in the winding resistance of the coil without deteriorating the formability of the insulator, and to improve motor performance. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a cross-sectional view of a motor with a reducer according to an embodiment of the present invention. [Figure 2] 1 is a plan view of a stator and a rotor according to a first embodiment of the present invention, viewed from the axial direction. [Figure 3] FIG. 1 is a perspective view of a stator according to a first embodiment of the present invention. [Figure 4] 2 is a plan view of a stator core according to an embodiment of the present invention, viewed from the axial direction. FIG. [Figure 5] 3 is a partially enlarged cross-sectional view taken along the axial direction of the winding drum covering portion of the long side winding drum in the first embodiment of the present invention. FIG. [Figure 6] 3 is a cross-sectional view along the axial direction of a portion of the winding drum covering portion of the narrow side winding drum in the first embodiment of the present invention. FIG. [Figure 7] 2 is a plan view of a stator core according to an embodiment of the present invention, viewed from the axial direction. FIG. [Figure 8] 2 is a plan view of a stator core according to an embodiment of the present invention, viewed from the axial direction. FIG. [Figure 9] FIG. 10 is a plan view of a stator core according to a modified example of the first embodiment of the present invention, viewed from the axial direction. [Figure 10] FIG. 10 is a cross-sectional view taken along the radial direction of a motor unit according to a second embodiment of the present invention. [Figure 11] 10 is an explanatory diagram of a method for setting the position of a locking portion in a second embodiment of the present invention. FIG. [Figure 12] 10A and 10B are explanatory diagrams illustrating the behavior of a coil when a locking portion is not provided in the second embodiment of the present invention, where (a) shows the state immediately after winding the coil, and (b) shows the state resulting from the application of tension to the wound coil. [Figure 13]10A and 10B are explanatory diagrams illustrating the behavior of a coil when a locking portion is formed in the second embodiment of the present invention, where (a) shows the state immediately after winding the coil, and (b) shows the state resulting from tension acting on the wound coil. [Figure 14] 10A and 10B are diagrams showing modified examples of the locking portion in the second embodiment of the present invention. [Figure 15] 10A and 10B are diagrams showing modified examples of the locking portion in the second embodiment of the present invention. [Figure 16] 10A and 10B are diagrams showing modified examples of the locking portion in the second embodiment of the present invention. [Figure 17] 10A and 10B are diagrams showing modified examples of the locking portion in the second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] Next, an embodiment of the present invention will be described with reference to the drawings.

[0028] [First embodiment] <Motor with reducer> FIG. 1 is a cross-sectional view of a motor 1 with a reducer. As shown in Figure 1, the motor with a reducer 1 includes a motor section 2 and a reduction section 3 that reduces the rotation of the motor section 2 and outputs the reduced speed. The motor section 2 and the reduction section 3 are arranged side by side. In the following description, the direction parallel to the rotation axis A of the motor section 2 is referred to as the axial direction.

[0029] <Deceleration part> The speed reducer 3 includes a gear case 4 and a worm reduction mechanism 5 housed in the gear case 4. The worm reduction mechanism 5 includes a worm shaft 6 arranged along the axial direction, and a worm wheel 7 meshed with the worm shaft 6. Both axial ends of the worm shaft 6 are rotatably supported by the gear case 4 via bearings 8a and 8b.

[0030] An opening 4a for receiving the motor unit 2 is formed in the side of the gear case 4 closer to the bearing 8b, which is located on the motor unit 2 side, of the two bearings 8a, 8b. The end of the worm shaft 6 on the motor unit 2 side protrudes toward the motor unit 2 through the bearing 8b and the opening 4a. A rotor shaft 16 of the motor unit 2, which will be described later, is integrally formed with the end of the worm shaft 6 on the motor unit 2 side.

[0031] An output shaft 9 is provided at the radial center of the worm wheel 7. The output shaft 9 is disposed coaxially with the rotational axis of the worm wheel 7 and protrudes to the outside of the gear case 4 via a bearing boss (not shown) of the gear case 4. A spline is formed at the protruding tip of the output shaft 9 so that it can be connected to an electrical component (not shown). Examples of electrical equipment include a sunroof, power windows, power seats, etc. However, the electrical equipment is not limited to these, and the output shaft 9 can be connected to various devices other than electrical equipment.

[0032] <Motor section> The motor section 2 is a so-called brushless motor that does not require brushes to supply power to the stator 12. The motor section 2 includes a motor case 11 that is provided to close the opening 4a of the gear case 4, an annular stator 12 housed within the motor case 11, and a rotor 13 that is provided radially inside the stator 12 and is rotatable relative to the stator 12.

[0033] <Motor case> The motor case 11 is formed in a cylindrical shape with a bottom. An outer flange portion 11b is formed around the periphery of an opening 11a of the motor case 11. The motor case 11 is fixed to the gear case 4 with the outer flange portion 11b abutting against the side surface of the gear case 4. A bearing boss 14 is formed on the bottom 11c of the motor case 11, protruding on the side opposite to the gear case 4. A bearing 15 for supporting the rotor 13 so that it can rotate freely is provided on the bearing boss 14.

[0034] <Rotor> FIG. 2 is a plan view of the stator 12 and the rotor 13 in the first embodiment as viewed from the axial direction. As shown in Figures 1 and 2, the rotor 13 comprises a rotor shaft 16 formed integrally with the worm shaft 6, a cylindrical rotor core 17 fitted and fixed to the rotor shaft 16, and a plurality of (for example, four in this embodiment) permanent magnets 18 provided on the outer peripheral surface of the rotor core 17.

[0035] The rotor shaft 16 is disposed coaxially with the worm shaft 6. The end of the rotor shaft 16 opposite to the worm shaft 6 is rotatably supported by the motor case 11 via a bearing 15. In the following description, the rotation direction of the rotor shaft 16 will be referred to as the circumferential direction, and the radial direction of the rotor shaft 16, that is, the direction perpendicular to the axial and circumferential directions, will be simply referred to as the radial direction.

[0036] The rotor core 17 is formed, for example, by stacking a plurality of steel plates in the axial direction. However, this is not limitative, and the rotor core 17 may be formed, for example, by pressure molding soft magnetic powder. A through hole 17a is formed in the radial center of the rotor core 17. The rotor shaft 16 is inserted or press-fitted into the through hole 17a and fixed. A plurality of (for example, four in this embodiment) salient poles 19 are provided on the outer peripheral surface 17b of the rotor core 17 at equal intervals in the circumferential direction. The salient poles 19 protrude radially outward and extend over the entire axial direction of the rotor core 17.

[0037] The permanent magnets 18 are arranged on the outer peripheral surface of the rotor core 17 and between adjacent salient poles 19 in the circumferential direction. When viewed from the axial direction, the permanent magnets 18 are formed in an arc shape along the outer peripheral surface 17b of the rotor core 17. When viewed from the axial direction, the permanent magnets 18 are formed symmetrically about the circumferential center. The permanent magnets 18 have an arc-shaped inner peripheral surface 18a on the radially inner side and an arc-shaped outer peripheral surface 18b on the radially outer side.

[0038] The position of the arc center Ci of the inner circumferential surface 18a of the permanent magnet 18 coincides with the position of the rotation axis A. In contrast, the position of the arc center Co of the outer circumferential surface 18b of the permanent magnet 18 is eccentrically shifted radially outward from the rotation axis A. As a result, the permanent magnet 18 is formed so that the circumferential center bulges outward most radially. The permanent magnets 18 are arranged so that their magnetic poles are staggered in the circumferential direction. Examples of the permanent magnets 18 include ferrite magnets, neodymium bonded magnets, and neodymium sintered magnets.

[0039] In this way, the rotor 13 is a surface permanent magnet (SPM) type rotor having permanent magnets 18 for the field on the outer surface 17b of the rotor core 17, and is also an inset type rotor having salient poles 19 that protrude radially outward from the rotor core 17 between the permanent magnets 18 arranged circumferentially.

[0040] <Stator> FIG. 3 is a perspective view of the stator 12 in the first embodiment. 1 to 3, the stator 12 includes a stator core 21 formed in an annular shape so as to surround the rotor 13, an insulator 40 that covers the periphery of the stator core 21, and a plurality of coils 22 that are wound around the stator core 21 from above the insulator 40. In Figs. 2 and 3, the coils 22 are illustrated simply to make the explanation easier to understand.

[0041] <Stator core> FIG. 4 is a plan view of the stator core 21 as viewed from the axial direction. 4, the stator core 21 is formed, for example, by stacking a plurality of steel plates in the axial direction. However, this is not limitative, and the stator core 21 may be formed, for example, by pressure molding soft magnetic powder.

[0042] The stator core 21 includes an annular back yoke 23 and six teeth 24 that protrude radially inward from the inner circumferential surface of the back yoke 23. A dovetail-shaped slot 25 is formed between each pair of adjacent teeth 24 in the circumferential direction. Since there are six teeth 24, there are also six slots 25. In this embodiment, for example, there are four permanent magnets 18, so the number of magnetic poles is four. In other words, the motor section 2 is a four-pole, six-slot brushless motor.

[0043] The back yoke 23 is formed in a flat shape when viewed in the axial direction. That is, the back yoke 23 has a pair of long sides 26 (an example of first sides in the claims) arranged opposite each other across the rotation axis A, and a pair of short sides 27 (an example of second sides in the claims) arranged opposite each other in a direction perpendicular to the opposing direction of the long sides 26 across the rotation axis A. Each long side 26 extends linearly in a direction perpendicular to the opposing direction when viewed from the axial direction. In other words, each long side 26 extends flatly along a direction perpendicular to the opposing direction. Each short side portion 27 has a short straight portion 28 extending in a direction perpendicular to the extension direction of the long side portion 26 as viewed from the axial direction, and a connecting portion 29 connecting the short straight portion 28 to the long side portion 26. The short straight portion 28 and the connecting portion 29 are each formed linearly as viewed from the axial direction. In other words, each short side portion 27 extends flat in a direction perpendicular to the opposing direction.

[0044] The connecting portions 29 are formed by chamfering the corners between the long side portions 26 and the short side portions 27. The connecting portions 29 are bent and extended from both ends of the short straight portion 28 in the circumferential direction. The length LLC between the pair of long side portions 26 passing through the rotation axis A is shorter than the length LSC between the pair of short side portions 27 (between the pair of short straight portions 28) that is perpendicular to the direction of this length LLC and passes through the rotation axis A. Furthermore, the length along the circumferential direction of the short side portion 27, that is, the length obtained by adding the length LS2 of the two connecting portions 29 to the length LS1 of the short straight portion 28 as seen in the axial direction, is shorter than the length LL of the long side portion 26 as seen in the axial direction.

[0045] The teeth 24 are integrally formed with a winding drum 31 that protrudes radially inward from the inner peripheral surface of the back yoke 23 and a flange 32 that extends circumferentially from the radially inner end of the winding drum 31. In the following description, when viewed from the axial direction, a line passing through the longitudinal center of each long side 26 is defined as a long side centerline Dl, and a line passing through the longitudinal center of each short side 27 is defined as a short side centerline Ds. Of the flanges 32, the flange 32 that extends from the radially inner end of the winding drum 31 toward the long side centerline Dl may be referred to as a first flange 32a. Of the flanges 32, the flange 32 that extends from the radially inner end of the winding drum 31 toward the short side centerline Ds may be referred to as a second flange 32b.

[0046] Each flange 32 has the same overall circumferential length from the first flange 32a to the second flange 32b, and is arranged at equal intervals in the circumferential direction. The flanges 32 are portions that generate magnetic attractive and repulsive forces to the permanent magnets 18 of the rotor 13 (details will be described later).

[0047] The six teeth 24 are composed of long side teeth 33 (an example of first side teeth in the claims) provided two on each of the pair of long side portions 26, and short side teeth 34 (an example of second side teeth in the claims) provided one on each of the pair of short side portions 27. In the following description, when distinguishing between the winding drum portion 31 that constitutes the long side teeth 33 and the winding drum portion 31 that constitutes the short side teeth 34, the winding drum portion 31 that constitutes the long side teeth 33 will be referred to as the long side winding drum portion 35. The winding drum portion 31 that constitutes the short side teeth 34 will be referred to as the short side winding drum portion 36. When distinguishing between the flange portion 32 of the long side teeth 33 and the flange portion 32 of the short side teeth 34, the flange portion 32 of the long side teeth 33 will be referred to as the long side flange portion 37. The flange portion 32 of the short side teeth 34 will be referred to as the short side flange portion 38.

[0048] The short side teeth 34 are provided at the center of the short side of the short side portion 27 when viewed from the axial direction. The short side winding trunk portion 36 protrudes in a direction perpendicular to the short straight portion 28, that is, along the radial direction. In contrast, the long side winding trunk portion 35 protrudes from the long side portion 26 in a direction that intersects with the radial direction. The roots 35a of the long side winding trunk portion 35 on the opposite side from the long side flange portion 37 are connected to both longitudinal ends of the long side portion 26 when viewed from the axial direction. That is, for one long side portion 26, the area between the roots 35a of the two long side teeth 33 is formed flat.

[0049] At the base 35a of the long side winding trunk 35, a recess 39 is formed on the side surface 35b facing the short side portion 27. The recess 39 is formed over the entire axial direction of the long side winding trunk 35. The recess 39 is tapered so that its width as viewed in the axial direction gradually decreases from the side surface 35b toward the long side portion 26.

[0050] <Insulator> As shown in Figures 2 to 4, the insulator 40 has a yoke covering portion 41 that covers the inner peripheral surface of the back yoke 23, a winding drum covering portion 42 that covers the periphery of the winding drum portion 31, and a flange covering portion 43 that covers the outer peripheral surface of the flange portion 32. The inner peripheral surface of the flange portion 32 is exposed. Inner walls 44 that protrude outward in the axial direction are integrally formed on both axial ends of the flange covering portion 43. The yoke covering portion 41 protrudes from the axial end portion of the back yoke 23. These protruding portions form outer walls 45 of the insulator 40.

[0051] 5 is an enlarged partial cross-sectional view of the winding drum covering portion 42 of the long side winding drum 35 in the first embodiment, taken along the axial direction, the winding drum covering portion 42 extending in a direction intersecting the radial direction. Hereinafter, this winding drum covering portion 42 may be referred to as the long side winding drum covering portion 51. FIG. 5 shows the axial end portion of the long side winding drum covering portion 51. 6 is a cross-sectional view along the axial direction of a portion of the winding drum covering portion 42 of the narrow side winding drum portion 36 that extends along the radial direction, among the winding drum covering portions 42 in the first embodiment. Hereinafter, this winding drum covering portion 42 may be referred to as the narrow side winding drum covering portion 52. FIG. 6 shows the axial end portion of the narrow side winding drum covering portion 52 and corresponds to FIG. 5. 5 and 6, thickened portions 47 are formed at the axial ends of the short side winding drum covering portion 52. Due to the thickened portions 47, the thickness T1 of the axial end of the short side winding drum covering portion 52 is thicker than the thickness T2 of the axial end of the long side winding drum covering portion 51.

[0052] In the insulator 40 configured in this manner, a coil accommodating recess 46 is formed by the yoke covering portion 41, which includes an inner wall 44 and an outer wall 45, the winding drum covering portion 42, and the flange covering portion 43. The coil 22 is wound around each tooth 24 from above the insulator 40 using a concentrated winding method so as to be accommodated in each coil accommodating recess 46. More specifically, the coil 22 is wound around each tooth 24 using a nozzle of a winding device (not shown). The nozzle (not shown) enters the slot 25 and unwinds the coil 22 while going around the periphery of the tooth 24. In this way, the coil 22 is wound around each tooth 24. The coils 22 are connected, for example, by a delta connection method.

[0053] <About winding area> Next, the winding area will be described with reference to FIG. 7 is a plan view of the stator core 21 as viewed from the axial direction, and corresponds to the above-mentioned FIG. 7, the back yoke 23 is formed in a flat shape when viewed in the axial direction. Therefore, the distance LK1 from the rotation axis A to the long side portion 26 is shorter than the distance LK2 from the rotation axis A to the short side portion 27. Therefore, the winding areas MA1, MA2 of the long side teeth 33 (first long side winding area MA1, second long side winding area MA2) tend to be smaller than the short side winding area MA3 of the short side teeth 34 (see the shaded areas in FIG. 4 for the winding areas MA1 to MA3).

[0054] However, the direction in which the long side winding trunk portion 35 protrudes from the long side portion 26 intersects with the radial direction. Therefore, the depth of the long side teeth 33 is deeper than when the long side winding trunk portion 35 protrudes in the radial direction from the long side portion 26. This allows the first long side winding area MA1 on the long side portion 26 side of the long side teeth 33 to be increased accordingly.

[0055] Next, the range of movement of the nozzle (not shown) will be considered based on FIG. 8 is a plan view of the stator core 21 as viewed from the axial direction, and corresponds to the above-mentioned FIG. As described above, a nozzle (not shown) enters between adjacent teeth 24 from the rotation axis A side and goes around the teeth 24, thereby winding the coil 22 around each tooth 24. Therefore, as shown in Fig. 8, when a line passing through the rotation axis A and the circumferential end of the flange portion 32 is denoted by S, the intersection of the line S with the back yoke is denoted by P, and the length between the rotation axis A and the intersection P is denoted by L, this length L affects the space factor of the coil 22 on each tooth 24.

[0056] More specifically, the length Lla of the straight line S that passes through the circumferential end of the first flange 32a of the long-side flange 37 is shorter than the length Llb of the straight line S that passes through the circumferential end of the second flange 32b of the long-side flange 37. Therefore, when winding the coil 22 around the long-side tooth 33, if a nozzle (not shown) extends up to the shorter of the two lengths Lla, Llb (an example of the shorter of the two lengths Ll in the claims), it becomes difficult to extend the nozzle any further. As a result, the winding range Cal of the coil 22 is roughly determined according to the shorter length Lla while making the long-side winding areas MA1, MA2 of the long-side tooth 33 as large as possible.

[0057] In the short-side flange 38, the length Lsa of the straight line S passing through the circumferential end of the first flange 32a and the length Lsb of the straight line S passing through the circumferential end of the second flange 32b are the same. Therefore, in the short-side flange 38, the shorter of the two lengths Lsa, Lsb (an example of the shorter of the two lengths Ls in the claims) may be either of the two lengths Lsa or Lsb. In the following description, the lengths Lla and Llb of the straight line S passing through the circumferential end of the long-side flange 37 are referred to as the lengths Lla and Llb of the long-side teeth 33. The lengths Lsa and Lsb of the straight line S passing through the circumferential end of the short-side flange 38 are referred to as the lengths Lsa and Lsb of the short-side teeth 34.

[0058] Here, the length Lla of the long-side teeth 33 is longer than the length Lsa (Lsb) of the short-side teeth 34. Therefore, just as the short-side winding area MA3 is larger than the long-side winding areas MA1 and MA2, the winding range Cas of the coil 22 on the short-side teeth 34 is larger than the winding range Cal of the long-side teeth 33.

[0059] That is, the coil 22 wound around the long side tooth 33 is more likely to be thicker than the coil 22 wound around the short side tooth 34. Therefore, a thick portion 47 is formed at the axial end of the short side winding drum covering portion 52. By forming the thick portion 47, the circumferential length of the coil 22 when going around the short side tooth 34 is longer than when the thick portion 47 is not formed. As a result, the variation in the winding resistance of the coil 22 wound around the long side tooth 33 and the coil 22 wound around the short side tooth 34 is suppressed.

[0060] <Operation of a motor with a reducer> Next, the operation of the speed reducer-equipped motor 1 will be described. The speed reducer-equipped motor 1 includes a controller (not shown) that selectively supplies current to each coil 22. When current is selectively supplied to each coil 22 via this controller, a flux linkage is formed in a predetermined tooth 24. The flux linkage flows through the winding body 31 and flange 32 of each tooth 24, and further flows from the flange 32 toward the rotor 13.

[0061] The interlinkage magnetic flux formed at each tooth 24 generates a magnetic attraction force or repulsion force (magnetic torque) between the effective magnetic flux formed by the permanent magnet 18 of the rotor 13 . In addition, the salient poles 19 of the rotor core 17 protrude in a direction that facilitates the flow of interlinkage magnetic flux from each flange portion 32, and generate a reluctance torque that rotates the rotor core 17 so as to reduce the magnetic resistance (reluctance) of the magnetic path of the interlinkage magnetic flux.

[0062] These magnetic torque and reluctance torque continuously rotate the rotor 13. The rotation of the rotor 13 is transmitted to the worm shaft 6, which is integrated with the rotor shaft 16. It is further transmitted to the worm wheel 7, which is meshed with the worm shaft 6. The rotation of the worm wheel 7 is transmitted to the output shaft 9, which is connected to the worm wheel 7. The rotation of the output shaft 9 drives desired electrical equipment.

[0063] <Actions and effects of each component> Next, the functions and effects of each configuration will be described. In the motor section 2 in the first embodiment described above, thick portions 47 are formed at the axial end portions of the short-side winding drum covering portions 52. With respect to the nozzle penetration distance, the length Lsa (Lsb) of the short-side teeth 34 covered by the short-side winding drum covering portions 52 is longer than the shorter length Lla of the two lengths Lla, Llb of the long-side teeth 33. By forming the thick portions 47 in the short-side winding drum covering portions 52 of the short-side teeth 34, the circumferential lengths of the coils 22 wound around each tooth 24 can be made uniform without extremely reducing the short-side winding area MA3. This suppresses variations in the winding resistance of the coils 22, improving the motor performance of the motor section 2.

[0064] Since the thick-walled portion 47 is simply formed in the short side winding drum covering portion 52, manufacturing is easier than when an insulating portion is provided as in the past, and increases in manufacturing costs can be suppressed. Deterioration of the formability of the insulator 40 can also be prevented.

[0065] The back yoke 23 is formed into a flat shape when viewed from the axial direction, and the teeth 24 are composed of long-side teeth 33 and short-side teeth 34. The distance LK1 from the rotation axis A to the long-side portion 26 is shorter than the distance LK2 from the rotation axis A to the short-side portion 27. In this shape, the long-side winding trunk portion 35 protruding from the long-side portion 26 extends in a direction intersecting the radial direction. This configuration allows the long-side teeth 33 to be longer than the teeth if they were extended radially at the same location. This allows for larger first long-side winding areas MA1 and second long-side winding areas MA2. However, the shorter the distance that the nozzle of the winding device can penetrate, the more likely the coil will thicken and collapse, resulting in higher winding resistance. Therefore, by forming the thick-walled portion 47 in the short-side winding trunk covering portion 52, the variation in winding resistance throughout the stator core 21 can be suppressed. Therefore, the motor performance of the motor section 2 can be improved to the maximum while the stator core 21 has a flat shape.

[0066] Since it is possible to improve motor performance while flattening the motor section 2, it will be possible to contribute to Goal 7 of the United Nations-led Sustainable Development Goals (SDGs), "Ensure access to affordable, reliable, sustainable and modern energy for all," and Goal 9, "Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation."

[0067] [Modification of the first embodiment] In the above-described first embodiment, the thick portion 47 is formed at the axial end of the short side winding drum covering portion 52. However, this is not limited to this, and the thick portion 47 may be formed separately from the short side winding drum covering portion 52, and the thick portion 47 may be provided at the axial end of the short side winding drum covering portion 52.

[0068] In the first embodiment described above, the stator core 21 has been described as having a flat back yoke 23. The short side portions 27 of the back yoke 23 have short straight portions 28 and connecting portions 29, and the connecting portions 29 are formed by chamfering the corners between the long side portions 26 and the short side portions 27. The short side teeth 34 are provided at the center of the short side portions 27 in the lateral direction when viewed from the axial direction. The short side winding trunk portions 36 protrude from the short side portions 27 in the radial direction. However, this is not limited thereto, and the stator core 21 may have any shape as long as the back yoke 23 has a flat shape. For example, the stator core 21 may be formed as follows.

[0069] 9 is a plan view of a stator core 21 according to a modification of the first embodiment, as viewed from the axial direction. FIG. 9 corresponds to FIG. 9, the length LS2 of the connecting portion 29 of the stator core 21 in this modification is longer than the length LS2 of the connecting portion 29 in the first embodiment. The connecting portion 29 in the modification is bent and extends from both circumferential ends of the short straight portion 28.

[0070] One long side tooth 33 protrudes from the longitudinal center of each long side portion 26 when viewed in the axial direction. The long side winding trunk portion 35 extends radially. One short side tooth 34 is provided at each connecting portion 29 of the short side portion 27. The short side winding trunk portion 36 extends radially. A length LLC between the pair of long side portions 26 passing through the rotation axis A is shorter than a length LSC between the pair of short side portions 27 (between the pair of short straight portions 28) that is perpendicular to the direction of this length LLC and passes through the rotation axis A.

[0071] Even in this configuration, the shorter of the two lengths Lla, Llb of the long-side teeth 33 is compared with the shorter of the two lengths Lsa, Lsb of the short-side teeth 34 in terms of the nozzle penetration distance, and a thick portion 47 is formed in the winding drum covering portion 42 of the longer tooth 24. In this modified example, the two lengths Lla and Llb of the long-side teeth 33 are the same. The two lengths Lsa and Lsb of the short-side teeth 34 are the same. Here, the length Lsa of the short-side teeth 34 is longer than the length Lla (Llb) of the long-side teeth 33 and the length Lsa (Lsb) of the short-side teeth 34. Therefore, a thick portion 47 is formed at the axial end of the short-side winding drum covering portion 52. This configuration achieves the same effects as the first embodiment described above.

[0072] In the first embodiment described above, the thick portion 47 is formed in the short side winding drum covered portion 52. However, this is not limited to this, and the thick portion 47 may be formed at the axial end of the winding drum covered portion 42 depending on the shape of the back yoke 23. That is, when the shorter of the two lengths Lla, Llb of the long side tooth 33 is Ll and the shorter of the two lengths Lsa, Lsb of the short side tooth 34 is Ls, the thick portion 47 may be formed at the axial end of the winding drum covered portion 42 that is the longer of the lengths Ll and Ls.

[0073] [Second embodiment] Next, a second embodiment will be described based on Fig. 10 to Fig. 13(b) with reference to Fig. 1. The same aspects as those in the first embodiment will be described with the same reference numerals. FIG. 10 is a cross-sectional view taken along the radial direction of a motor unit 202 according to the second embodiment. The second embodiment is similar to the first embodiment in that, for example, a motor unit 202 is used in a motor with a reducer 1. The motor unit 202 is a so-called brushless motor, and the stator 212 is similar to the first embodiment in that it includes a stator core 21 formed in an annular shape so as to surround the periphery of the rotor 13, an insulator 240 covering the periphery of the stator core 21, and a plurality of coils 22 wound around the stator core 21 from above the insulator 240.

[0074] The stator core 21 is similar to the first embodiment in that it is composed of an annular back yoke 23, long side teeth 33, and short side teeth 34. Similar to the first embodiment, the short side teeth 34 are provided at the center of the short side portion 27 in the short direction as viewed in the axial direction, and the short side winding trunk portion 36 extends along the radial direction. Similar to the first embodiment, the long side teeth 33 are provided at both ends of the long side portion 26 in the longitudinal direction as viewed in the axial direction, and the long side winding trunk portion 35 extends in a direction intersecting the radial direction.

[0075] Here, as shown in FIG. 10, the difference between the first embodiment and the second embodiment is that the insulator 40 of the first embodiment described above has a thick portion 47, whereas the insulator 240 of the second embodiment has a locking portion 60. More specifically, the flange covering portion 43 that covers the outer peripheral surface of the first flange portion 32a in the long-side flange portion 37 has a thick portion 61 formed therein.

[0076] The thick portion 61 is thicker than other portions including the winding drum covering portion 42. This thick portion 61 forms a V-groove-shaped locking portion 60 at the connection portion between the winding drum covering portion 42 and the flange covering portion 43 of the insulator 240. The coil 22 is locked by fitting into the locking portion 60. The coil 22 is locked by the locking portion 60 on the first flange portion 32a side, and is locked by contact with the flange covering portion 43 on the second flange portion 32b side.

[0077] The locking portion 60 is intended to prevent the coil 22 from becoming unwound by locking the coil 22 placed on the first flange portion 32a of the long side flange portion 37. This is because the first angle θ1 between the first flange portion 32a and the long side winding trunk portion 35 is larger than the second angle θ2 between the second flange portion 32b and the long side winding trunk portion 35, making it easier for the coil 22 to become unwound. A method for setting the position of the locking portion 60 will be described in detail below.

[0078] <How to set the position of the locking part> FIG. 11 is an explanatory diagram of a method for setting the position of the locking portion 60 in the second embodiment. As shown in FIG. 11 , first, when viewed from the axial direction, the coil 22 that contacts the flange covering portion 43 is referred to as the flanged portion coil 22t. The coil 22 that is locked by the locking portion 60 is referred to as the locked portion coil 22k. A line connecting the center of the flanged portion coil 22t and the center of the locked portion coil 22k is referred to as a first line L1. The first line L1 can also be interpreted as a line connecting the centers of the coils 22 on both sides of the long side winding trunk 35 when the coil 22 makes one revolution around the long side winding trunk 35 when viewed from the axial direction. The intersection of the first line L1 and the center line LTc of the long side winding trunk 35 is referred to as Q. A line that passes through the intersection Q and is perpendicular to the center line LTc is referred to as a second line L2. A line that passes through the center of the locked portion coil 22k and is parallel to the second line L2 is referred to as a third line L3.

[0079] At this time, the position of the locking portion 60 is set so that the length N1 between the second straight line L2 and the third straight line L3 is smaller than the diameter of the coil 22. Hereinafter, this condition will be referred to as the positioning condition of the locking portion 60. Note that the length N1 is equal to the length N2 between the second straight line L2 and a fourth straight line that passes through the center of the flanged portion coil 22t and is parallel to the second straight line L2.

[0080] Next, the reasons for the positioning conditions of the locking portion 60 will be explained with reference to FIGS. Figure 12 is an explanatory diagram explaining the behavior of the coil 22 when the locking portion 60 (thick portion 61) is not provided, where (a) shows the state immediately after winding the coil 22, and (b) shows the state resulting from tension acting on the wound coil 22.

[0081] 12(a), when the locking portion 60 is not formed, the coil 22 is locked by the first flange portion 32a side also contacting the flange covering portion 43. In this situation, a portion of the coils 22 stacked in bales (hereinafter, this coil 22 is referred to as a portion of the coils 22p) will be considered. When viewed from the axial direction, the coil 22 makes one revolution around the long side winding trunk 35. When the intersection point of the center line LCc connecting the centers of the coils 22 on both sides of the long side winding trunk 35 and the center line LTc of the long side winding trunk 35 is designated as Q', a tension F1 acting toward the intersection point Q' acts on some of the coils 22p. The tension F1 can be broken down into a parallel component F2 parallel to the center line LTc of the long side winding trunk 35 and a perpendicular component F3 perpendicular to the center line LTc of the long side winding trunk 35.

[0082] Now, suppose that a portion of the coil 22p loosens after winding the coil 22. At this time, due to the action of the parallel component force F2, the portion of the coil 22p tries to move a length N3 so as to approach the intersection Q'. Here, on the side of the first flange 32a, the portion of the coil 22p is closer to the first flange 32a because the locking portion 60 is not formed. For this reason, the length N3 is likely to be larger than the diameter of the coil 22. As a result, as shown in FIG. 12(b), the parallel component force F2 causes the portion of the coil 22p to move across the adjacent coil 22 (see arrow Y1 in FIG. 12(b)). This causes the coil 22 to become unwound.

[0083] Figure 13 is an explanatory diagram explaining the behavior of the coil 22 when the locking portion 60 is formed, where (a) shows the state immediately after winding the coil 22, and (b) shows the state resulting from tension acting on the wound coil 22. 13(a), when the locking portion 60 is formed, when a tension F1' toward the intersection Q' acts on the partial coil 22p, the partial coil 22p attempts to move a length N1. Due to the locking portion 60, the length N1 is smaller than the diameter of the coil 22.

[0084] 13(b), even when a parallel component force F2' is applied, some of the coils 22p do not move across the adjacent coils 22 (see arrow Y2 in FIG. 13(b)). Therefore, the coils 22 are less likely to become unwound. Furthermore, the vertical component force F3' acting on the coil 22 when the locking portion 60 is formed is greater than the vertical component force F3 acting on the coil 22 when the locking portion 60 is not formed. Therefore, the coil 22 is less likely to become loose.

[0085] As described above, in the insulator 240 of the second embodiment, a thick portion 61 is formed in the flange covering portion 43 that covers the outer peripheral surface of the first flange portion 32a in the long side flange portion 37. The thick portion 61 forms a V-groove-shaped locking portion 60 at the connection between the winding drum covering portion 42 and the flange covering portion 43 of the insulator 240. The first angle θ1 between the first flange portion 32a on the side where the locking portion 60 is formed and the long side winding trunk portion 35 is larger than the second angle θ2 between the second flange portion 32b and the long side winding trunk portion 35. The position of the locking portion 60 is set to satisfy positioning conditions.

[0086] This configuration makes it possible to maximize the long side winding areas MA1, MA2 of the long side teeth 33 (see FIG. 7 above), while preventing the coil from collapsing around the long side teeth 33. As a result, it is possible to suppress variations in the winding resistance of the coil 22, and improve the motor performance of the motor section 202. To prevent the coil 22 from becoming unwound, it is only necessary to provide the locking portion 60 on the insulator 240. This simplifies manufacturing compared to the conventional case in which an insulating portion is provided, and it is possible to suppress increases in manufacturing costs.

[0087] The locking portion 60 is formed by the thick portion 61 of the flange covering portion 43. Since it is only necessary to form the thick portion 61, the locking portion 60 can be easily formed. This makes it possible to suppress an increase in the manufacturing cost of the insulator 240 and also to prevent deterioration in the formability of the insulator 240.

[0088] [Modification of the second embodiment] In the second embodiment described above, the locking portion 60 is formed on the flange covering portion 43 side that covers the outer peripheral surface of the first flange portion 32a in the long side flange portion 37. The description has been given of the case where the locking portion 60 is formed by the thick portion 61 of the flange covering portion 43. However, this is not limited to this, and the locking portion 60 may be formed at a predetermined location according to the shape of the tooth 24. In other words, it is sufficient if the locking portion 60 can lock the coil 22 at the larger angle of the first angle θ1 between the first flange portion 32a and the long side winding trunk portion 35 and the second angle θ2 between the second flange portion 32b and the long side winding trunk portion 35. The locking portion 60 may have any shape as long as it can lock the coil 22. For example, the locking portion 60 may be formed as follows.

[0089] Figures 14 to 17 are views showing modified examples of the locking portion 60 in the second embodiment. Figures 14 to 16 correspond to the above-mentioned Figure 11. Figure 17 corresponds to a part of the above-mentioned Figure 2. As shown in FIG. 14, the thick portion 61 formed on the flange covering portion 43 of the first flange portion 32a may be locked so as to become gradually thicker toward the end portion in the circumferential direction of the first flange portion 32a. As shown in FIG. 15, a thick portion 61 may be formed only in a part of the flange covering portion 43. As shown in FIG. 16, a recess 62 may be formed at the connection between the hoisting drum covering portion 42 and the flange covering portion 43, and the recess 62 may form the locking portion 60. 17, a protrusion 63 may be formed on the axial end of the winding drum covering portion 42, and this protrusion 63 may serve as the locking portion 60. In other words, the protrusion 63 restricts the winding direction of the coil 22, and as a result, the protrusion 63 serves the same purpose as the locking portion 60.

[0090] [Other variations] The present invention is not limited to the above-described embodiment, and includes various modifications to the above-described embodiment without departing from the spirit of the present invention. For example, the configuration of the insulator 40 of the first embodiment may be combined with the configuration of the insulator 240 of the second embodiment. Also, each embodiment may be combined with each modified example.

[0091] In the above embodiment, the long side portions 26 extend linearly in a direction perpendicular to the opposing direction as viewed from the axial direction. The short side portions 27 have short straight portions 28 extending in a direction perpendicular to the extension direction of the long side portions 26 as viewed from the axial direction, and connecting portions 29 connecting the short straight portions 28 and the long side portions 26. The short straight portions 28 and connecting portions 29 are each formed linearly as viewed from the axial direction. The connecting portions 29 extend from both circumferential ends of the short straight portions 28 in a bent manner as viewed from the circumferential direction.

[0092] However, the present invention is not limited to this, and it is sufficient that the back yoke 23 is formed in a flat shape when viewed in the axial direction, and the length along the circumferential direction of the short side portions 27 is shorter than the length along the circumferential direction of the long side portions 26. For example, the long side portions 26 may be formed in a curved shape. It is sufficient that the six teeth 24 are composed of two long side teeth 33 provided on each of the pair of long side portions 26, and one short side tooth 34 provided on each of the pair of short side portions 27.

[0093] In the above embodiment, the motor unit 2 is described as being provided in the speed reducer-equipped motor 1. However, this is not limited to this, and the motor unit 2 can be used alone, or the motor unit 2 can be employed in various devices. [Explanation of symbols]

[0094] 1...motor with reducer, 2...motor section, 3...reduction section, 4...gear case, 4a...opening, 5...worm reduction mechanism, 6...worm shaft, 7...worm wheel, 8a...bearing, 8b...bearing, 9...output shaft, 11...motor case, 11a...opening, 11b...outer flange section, 11c...bottom, 12...stator, 13...rotor, 14...bearing boss, 15...bearing, 16...rotor shaft, 17...rotor core, 17a...through hole, 17b...outer surface, 18...permanent magnet, 18a...inner surface, 18b...outer surface, 19...salient pole, 21...stator core, 22...coil, 22k ...Latched portion coil, 22p...Part of coil, 22t...Flanged portion coil, 23...Back yoke, 24...Teeth, 25...Slot, 26...Long side portion (first side portion), 27...Short side portion (second side portion), 28...Short straight portion, 29...Connecting portion, 31...Winding drum portion, 32...Flange portion, 32a...First flange portion, 32b...Second flange portion, 33...Long side tooth (first side tooth), 34...Short side tooth (second side tooth), 35...Long side winding drum portion, 35a...Root, 35b...Side, 36...Short side winding drum portion, 37...Long side flange portion, 38...Short side flange portion, 39...Recess, 40...Insulator, 41...Yoke covering portion, 4 2...winding drum covering portion, 43...flange covering portion, 44...inner wall, 45...outer wall, 46...coil storage recess, 47...thick portion, 51...long side winding drum covering portion, 52...narrow side winding drum covering portion, 60...locking portion, 61...thick portion, 62...recess, 63...projection portion, 202...motor portion, 212...stator, 240...insulator, A...rotation axis, Cal...winding range, Cas...winding range, Ci...arc center, Co...arc center, Dl...long side center line, Ds...narrow side center line, F1...tension, F1'...tension, F2...parallel component force, F2'...parallel component force, F3...vertical component force, F3'...vertical component force, L...length, L1...first straight line , L2...second straight line, L3...third straight line, LCc...center line, LK1...distance, LK2...distance, LL...length, Lla(Ll)...length, Llb(Ll)...length, LM1...length, LM2...length, LS1...length, LS2...length, Lsa(Ls)...length, Lsb(Ls)...length, LT1...length, LT2...length, LTc...center line, MA1...first long side winding area, MA2...second long side winding area, MA3...narrow side winding area, N1...length, N2...length, N3...length, P...intersection point, Q...intersection point, Q'...intersection point, S...straight line, T1...thickness, T2...thickness, θ1...first angle, θ2...second angle

Claims

1. an annular stator; a rotor disposed radially inside the stator and rotatable relative to the stator; Equipped with The stator includes: A stator core; an insulator that covers the periphery of the stator core; a coil wound around the stator core from above the insulator; Equipped with The stator core is a back yoke having a flat and annular shape when viewed from the direction of the rotation axis of the rotor; a plurality of teeth that protrude radially inward from an inner peripheral surface of the back yoke and around which the coil is wound; Equipped with The back yoke is a pair of first side portions disposed opposite each other across the rotation axis; a pair of second side portions disposed opposite each other in a direction perpendicular to the opposing direction of the first side portions across the rotation axis; and Each of the teeth is a winding drum portion that protrudes from an inner peripheral surface of the back yoke and on which the coil is wound; a flange portion provided at an end of the winding drum opposite to the back yoke and extending in a circumferential direction longer than the circumferential width of the winding drum; and Each of the teeth is first side teeth provided on the pair of first side portions; second side teeth provided on the pair of second side portions; and The insulator is a winding drum covering portion that covers the periphery of the winding drum; a flange covering portion that covers an outer peripheral surface of the flange portion; and When the intersection of the back yoke and a straight line passing through the rotation axis and the circumferential end of the flange portion is defined as P, the length between the intersection P and the rotation axis is defined as L, the shorter of the two lengths L of the first side teeth is defined as Ll, and the shorter of the two lengths L of the second side teeth is defined as Ls, The end of the longer of the lengths Ll and Ls in the direction of the rotation axis of the winding drum covering portion is provided with a thick portion that is thicker than the end of the shorter of the winding drum covering portion in the direction of the rotation axis. A brushless motor characterized by:

2. the winding trunk portion of one of the first side teeth and the second side teeth extends along a radial direction, and the winding trunk portion of the other of the first side teeth extends in a direction intersecting the radial direction, The winding drum covering portion in the winding drum portion extending along the radial direction has the thick portion, 2. The brushless motor according to claim 1.

3. The flange portion is a first flange portion extending from the winding drum portion in a first circumferential direction; a second flange portion extending from the winding drum portion in a second direction circumferentially opposite to the first direction; and the insulator of the tooth having the winding drum portion extending in a direction intersecting the radial direction has a locking portion provided at a connection portion between the winding drum covering portion and the flange covering portion, the locking portion locks the coil disposed at a larger angle of a first angle between the winding drum and the first flange portion and a second angle between the winding drum and the second flange portion, When viewed from the direction of the rotation axis, the coil in contact with the flange covering portion is defined as the flanged portion coil, the coil locked by the locking portion is defined as the locked portion coil, a line connecting the center of the flanged portion coil and the center of the locked portion coil is defined as a first line, the intersection of the first line and the center line of the winding drum is defined as Q, a line passing through the intersection Q and perpendicular to the center line is defined as a second line, and a line passing through the center of the locked portion coil and parallel to the second line is defined as a third line, The length between the second straight line and the third straight line is smaller than the diameter of the coil.

3. The brushless motor according to claim 2.

4. an annular stator; a rotor disposed radially inside the stator and rotatable relative to the stator; Equipped with The stator includes: A stator core; an insulator that covers the periphery of the stator core; a coil wound around the stator core from above the insulator; Equipped with The stator core is a back yoke having a flat and annular shape when viewed from the direction of the rotation axis of the rotor; a plurality of teeth that protrude radially inward from an inner peripheral surface of the back yoke and around which the coil is wound; Equipped with The back yoke is a pair of first side portions disposed opposite each other across the rotation axis; a pair of second side portions disposed opposite each other in a direction perpendicular to the opposing direction of the first side portions across the rotation axis; and Each of the teeth is a winding drum portion that protrudes from an inner peripheral surface of the back yoke and on which the coil is wound; a flange portion provided at an end of the winding drum opposite to the back yoke and extending in a circumferential direction longer than the circumferential width of the winding drum; and Each of the teeth is first side teeth provided on the pair of first side portions; second side teeth provided on the pair of second side portions; and The insulator is a winding drum covering portion that covers the periphery of the winding drum; a flange covering portion that covers an outer peripheral surface of the flange portion; and the winding trunk portion of one of the first side teeth and the second side teeth extends along a radial direction, and the winding trunk portion of the other of the first side teeth extends in a direction intersecting the radial direction, An end portion of the drum covering portion of the drum portion extending along the radial direction in the direction of the rotation axis is provided with a thick portion that is thicker than an end portion of the drum covering portion of the drum portion extending in a direction intersecting the radial direction in the direction of the rotation axis. A brushless motor characterized by:

5. The flange portion is a first flange portion extending from the winding drum portion in a first circumferential direction; a second flange portion extending from the winding drum portion in a second direction circumferentially opposite to the first direction; and the insulator of the tooth having the winding drum portion extending in a direction intersecting the radial direction has a locking portion provided at a connection portion between the winding drum covering portion and the flange covering portion, the locking portion locks the coil disposed at a larger angle of a first angle between the winding drum and the first flange portion and a second angle between the winding drum and the second flange portion, When viewed from the direction of the rotation axis, the coil in contact with the flange covering portion is defined as the flanged portion coil, the coil locked by the locking portion is defined as the locked portion coil, a line connecting the center of the flanged portion coil and the center of the locked portion coil is defined as a first line, the intersection of the first line and the center line of the winding drum is defined as Q, a line passing through the intersection Q and perpendicular to the center line is defined as a second line, and a line passing through the center of the locked portion coil and parallel to the second line is defined as a third line, The length between the second straight line and the third straight line is smaller than the diameter of the coil.

5. The brushless motor according to claim 4.

6. an annular stator; a rotor disposed radially inside the stator and rotatable relative to the stator; Equipped with The stator includes: A stator core; an insulator that covers the periphery of the stator core; a coil wound around the stator core from above the insulator; Equipped with The stator core is a back yoke having a flat and annular shape when viewed from the direction of the rotation axis of the rotor; a plurality of teeth that protrude radially inward from an inner peripheral surface of the back yoke and around which the coil is wound; Equipped with The back yoke is a pair of first side portions disposed opposite each other across the rotation axis; a pair of second side portions disposed opposite each other in a direction perpendicular to the opposing direction of the first side portions across the rotation axis; and Each of the teeth is a winding drum portion that protrudes from an inner peripheral surface of the back yoke and on which the coil is wound; a flange portion provided at an end of the winding drum opposite to the back yoke and extending in a circumferential direction longer than the circumferential width of the winding drum; and Each of the teeth is first side teeth provided on the pair of first side portions; second side teeth provided on the pair of second side portions; and the winding trunk portion of one of the first side teeth and the second side teeth extends along a radial direction, and the winding trunk portion of the other of the first side teeth extends in a direction intersecting the radial direction, The flange portion is a first flange portion extending from the winding drum portion in a first circumferential direction; a second flange portion extending from the winding drum portion in a second direction circumferentially opposite to the first direction; and The insulator is a winding drum covering portion that covers the periphery of the winding drum; a flange covering portion that covers an outer peripheral surface of the flange portion; and the insulator of the tooth having the winding drum portion extending in a direction intersecting the radial direction has a locking portion provided at a connection portion between the winding drum covering portion and the flange covering portion, the locking portion locks the coil disposed at a larger angle of a first angle between the winding drum and the first flange portion and a second angle between the winding drum and the second flange portion, When viewed from the direction of the rotation axis, the coil in contact with the flange covering portion is defined as the flanged portion coil, the coil locked by the locking portion is defined as the locked portion coil, a line connecting the center of the flanged portion coil and the center of the locked portion coil is defined as a first line, the intersection of the first line and the center line of the winding drum is defined as Q, a line passing through the intersection Q and perpendicular to the center line is defined as a second line, and a line passing through the center of the locked portion coil and parallel to the second line is defined as a third line, The length between the second straight line and the third straight line is smaller than the diameter of the coil. A brushless motor characterized by:

7. The locking portion is formed by making the thickness of the flange covering portion thicker than the thickness of the winding drum covering portion.

7. The brushless motor according to claim 3, 5 or 6.

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