Motor and Power Tool

Abstract

To provide a motor and a power tool that easily reduce stator wiring and easily reduce the Joule loss.SOLUTION: A motor 1 comprises a stator 2 having a stator core 20 and stator wiring 21, and a rotor 3. The stator core 20 has a teeth core 4 and a yoke core 5. The teeth core 4 has an inner cylinder part 41, and a plurality of teeth 42 each including a trunk 421 projecting outwardly from the inner cylinder part 41 in a radial direction of the inner cylinder part 41. The yoke core 5 is attached to the plurality of teeth 42 and has a cylindrical shape surrounding the plurality of teeth 42. The stator wiring 21 has coil wires 22 each wound around the trunk 421, and crossover wiring 23 electrically connecting the coil wires 22 wound around the plurality of trunks 421. The crossover wiring 23 is located in inside parts 46 in the radial direction of the trunks 421.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure relates to a motor and a power tool, and more particularly, to a motor including a stator core and a rotor, and a power tool including the motor.

Background Art

[0002] Patent Document 1 discloses a disk drive motor in which both end edges of an annular yoke are caulked and fixed so as to be in a sealed state over the entire circumference.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the disk drive motor described in Patent Document 1, the arrangement of the coils is not specifically disclosed, and there is a problem that the electric wires are likely to be bulky and the joule loss is likely to increase.

[0005] An object of the present disclosure is to provide a motor and a power tool that can easily reduce stator wiring and easily reduce joule loss.

Means for Solving the Problems

[0006] A motor according to one aspect of the present disclosure includes a stator having a stator core and stator wiring, and a rotor having magnets and rotating with respect to the stator core. The stator core has a tooth core and a yoke core. The tooth core has a cylindrical inner cylinder portion where the rotor is disposed inside, and a plurality of teeth each including a body portion protruding outward in the radial direction of the inner cylinder portion from the inner cylinder portion. The yoke core is attached to the plurality of teeth and forms a cylindrical shape surrounding the plurality of teeth. The stator wiring has coil wires wound around the body portions, and jumper wires electrically connecting the plurality of coil wires wound around the plurality of body portions. The jumper wires are located at inner portions in the radial direction of the body portions.

[0007] A power tool according to one aspect of the present disclosure includes the motor.

Advantages of the Invention

[0008] In the motor and the power tool of the present disclosure, it is easy to reduce the stator wiring, and it is easy to reduce the Joule loss.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

[0010] Hereinafter, an electric tool according to an embodiment and a motor provided in the electric tool will be described with reference to the drawings. However, the following embodiment is merely one of various embodiments of the present disclosure. The following embodiment can be variously modified according to the design and the like as long as the object of the present disclosure can be achieved. Also, each drawing described in the following embodiment is a schematic diagram, and the ratio of the size and thickness of each component in the drawing does not necessarily reflect the actual dimensional ratio.

[0011] (1) Electric tool As shown in FIGS. 1 and 2, the electric tool 10 includes a motor 1. As shown in FIG. 2, the electric tool 10 further includes a power source 101, a drive transmission unit 102, an output unit 103, a chuck 104, a tip tool 105, a trigger volume 106, and a control circuit 107. The electric tool 10 is a tool that drives the tip tool 105 with the driving force of the motor 1.

[0012] The motor 1 is a drive source for driving the tip tool 105. The motor 1 is, for example, a brushless motor. The power source 101 is a DC power source that supplies a current for driving the motor 1. The power source 101 includes, for example, one or more secondary batteries. The drive transmission unit 102 adjusts the output (driving force) of the motor 1 and outputs it to the output unit 103. The output unit 103 is a part that is driven (for example, rotated) by the driving force output from the drive transmission unit 102. The chuck 104 is fixed to the output unit 103 and is a part to which the tip tool 105 is detachably attached. The tip tool 105 (also referred to as a bit) is, for example, a driver, a socket, or a drill. Among various tip tools 105, a tip tool 105 corresponding to the application is attached to the chuck 104 and used.

[0013] The trigger volume 106 is an operation unit that receives an operation for controlling the rotation of the motor 1. By operating the trigger volume 106 to pull it, the motor 1 can be switched between on and off. Also, the rotational speed of the output unit 103, that is, the rotational speed of the motor 1, can be adjusted by the amount of operation of the operation of pulling in the trigger volume 106. The control circuit 107 rotates or stops the motor 1 and controls the rotational speed of the motor 1 according to the operation input to the trigger volume 106. In this power tool 10, the tip tool 105 is attached to the chuck 104. Then, by controlling the rotational speed of the motor 1 by operating the trigger volume 106, the rotational speed of the tip tool 105 is controlled.

[0014] Note that the power tool 10 of the embodiment includes the chuck 104, so that the tip tool 105 can be replaced according to the application, but it is not necessary for the tip tool 105 to be replaceable. For example, the power tool 10 may be a power tool that can use only a specific tip tool 105.

[0015] (2) Motor Next, with reference to FIG. 1 and the like, the configuration of the motor 1 will be described. The motor 1 includes a stator 2 and a rotor 3. The rotor 3 has an output shaft 32. The stator 2 has a stator core 20 and a stator wiring 21. The rotor 3 rotates around the central axis 320 of the output shaft 32 with respect to the stator 2. That is, an electromagnetic force that rotates the rotor 3 is generated by the magnetic flux generated from a plurality (nine in FIG. 1) of coil wires 22 wound around the stator core 20. The motor 1 transmits the rotational force (driving force) of the rotor 3 from the output shaft 32 to the drive transmission unit 102 (see FIG. 2).

[0016] The stator core 20 has a tooth core 4 and a yoke core 5. The yoke core 5 is attached to the tooth core 4. The tooth core 4 has a cylindrical inner cylinder portion 41 and a plurality (nine in FIG. 1) of teeth 42. Inside the inner cylinder portion 41, a rotor 3 is disposed. Each of the plurality of teeth 42 includes a body portion 421 and two tip pieces 422. The body portion 421 protrudes outward in the radial direction of the inner cylinder portion 41 from the inner cylinder portion 41. In the present embodiment, a plurality (nine in FIG. 1) of body portions 421 are formed at intervals in the circumferential direction on the inner cylinder portion 41.

[0017] The two tip pieces 422 extend from a portion on the tip side of the body portion 421 in a direction intersecting the protruding direction of the body portion 421. A coil wire 22 is wound around the body portion 421 via an insulator 6 (see FIG. 3) described later.

[0018] The two tip pieces 422 are provided as a retaining means for suppressing the coil wire 22 from falling off the body portion 421. That is, when the coil wire 22 attempts to move to the tip side of the body portion 421, the coil wire 22 is caught by the two tip pieces 422, thereby suppressing the coil wire 22 from falling off.

[0019] The rotor 3 has a cylindrical rotor core 30, a plurality (six in FIG. 1) of permanent magnets 31, and an output shaft 32. The output shaft 32 is held inside the rotor core 30. The permanent magnets 31 are arranged in a polygonal shape (hexagonal shape).

[0020] Next, details of the configuration of the stator core 20 will be described. As shown in FIGS. 3 and 4, the tooth core 4 of the stator core 20 includes a plurality of steel plates 40. The tooth core 4 is formed by laminating a plurality of steel plates 40 in the thickness direction. Each steel plate 40 is formed of a magnetic material. Each steel plate 40 is, for example, a silicon steel plate.

[0021] As shown in FIG. 5A, the shape of the inner cylinder part 41 is cylindrical, and its central axis coincides with the central axis 320 of the output shaft 32 (see FIGS. 3 and 4). The thickness direction of the plurality of steel plates 40 coincides with the central axis 320 direction. The inner cylinder part 41 is continuous in the circumferential direction. In other words, the inner cylinder part 41 is connected without interruption in the circumferential direction.

[0022] The shape of the body part 421 of the plurality of teeth 42 is a rectangular parallelepiped. The body part 421 protrudes outward in the radial direction of the inner cylinder part 41 from the inner cylinder part 41. The body parts 421 of the plurality of teeth 42 are provided at equal intervals in the circumferential direction of the inner cylinder part 41.

[0023] The two tip pieces 422 extend from the tip-side part of the body part 421 in a direction intersecting the protruding direction of the body part 421. More specifically, the two tip pieces 422 are provided on both sides in the circumferential direction of the inner cylinder part 41 at the tip-side part of the body part 421. And the two tip pieces 422 extend in the circumferential direction of the inner cylinder part 41.

[0024] Among the respective tip pieces 422, the outer surface in the radial direction of the inner cylinder part 41 includes a curved surface 44. When viewed from the central axis 320 direction, the shape of the curved surface 44 is an arc shape along a circle concentric with the inner cylinder part 41.

[0025] Each tip piece 422 has a curved part 45 at the part connected to the body part 421. The curved part 45 is curved so as to be farther from the body part 421 in the circumferential direction of the inner cylinder part 41 as it is farther outward in the radial direction of the inner cylinder part 41. That is, the curved part 45, which is the base-end side part of each tip piece 422, is chamfered and has an R shape.

[0026] The inner cylinder part 41 has a plurality (nine in this embodiment) of connecting parts 410 which are parts connecting adjacent body parts 421 to each other. The connecting parts 410 are formed in an arc shape when viewed from the central axis 320 direction.

[0027] A part of the inner cylinder portion 41 is formed with an elastic deformation portion 43. The elastic deformation portion 43 will be described in detail in the section (3) Characteristic Configuration of the Motor, which will be described later.

[0028] As shown in FIGS. 3 and 7, the stator wiring 21 includes a coil wire 22 wound around the body portion 421 and a jumper wire 23 that electrically connects the coil wires 22 wound around the plurality of body portions 421.

[0029] As shown in FIG. 1, nine coil wires 22 are provided corresponding to the nine teeth 42. The electric wires constituting each coil wire 22 and the jumper wire 23 are, for example, enameled wires. This winding has a linear conductor and an insulating coating covering the conductor. The stator wiring 21 is constituted by a single electric wire.

[0030] The stator core 20 further includes an insulator 6 covering the tooth core 4. The insulator 6 is formed of, for example, a synthetic resin. The insulator 6 has electrical insulation properties. The insulator 6 covers at least a part of the plurality of teeth 42.

[0031] As shown in FIGS. 3 and 4, the insulator 6 is composed of two members, a first insulator 61 and a second insulator 62. The first insulator 61 and the second insulator 62 are arranged along the central axis 320 direction. The first insulator 61 and the second insulator 62 are formed in a shape into which a plurality of teeth 42 can be fitted from the central axis 320 direction. That is, the first insulator 61 is attached to the tooth core 4 and covers a plurality of teeth 42 from one end side in the central axis 320 direction (the left side in FIG. 3, hereinafter simply referred to as the left side), and the second insulator 62 covers a plurality of teeth 42 from the other end side in the central axis 320 direction (the right side in FIG. 3, hereinafter simply referred to as the right side). The first insulator 61 and the second insulator 62 have a cylindrical body 63 that overlaps with the inner cylinder portion 41 when viewed from the central axis 320 direction, and a plurality (nine in FIG. 6) of tooth covering portions 64 that cover the plurality of teeth 42. The cylindrical body 63 is formed in a cylindrical shape concentric with the inner cylinder portion 41, and its central axis coincides with the central axis 320 of the output shaft 32. Each tooth covering portion 64 protrudes outward in the radial direction of the cylindrical body 63 from the cylindrical body 63.

[0032] As shown in FIG. 6, the second insulator 62 has a plate portion 66 inside the cylindrical body 63. A hole 660 into which the outer ring of the second bearing 34 (see FIG. 3), which will be described later, is fitted is formed in the center of the plate portion 66. A guide support portion 26 is formed on the surface 60 of the plate portion 66. The guide support portion 26 will be described in detail in the section (3) Characteristic Configuration of the Motor described later.

[0033] As shown in FIG. 3, with the first insulator 61 and the second insulator 62 attached to the tooth core 4 and covering at least a part of the plurality of teeth 42, the coil wire 22 is wound around the body portion 421 via the insulator 6 formed by the first insulator 61 and the second insulator 62. Here, the coil wire 22 is wound around the body portion 421 so as to pass through the body portion 421 and the slots (voids) between the two body portions 421 adjacent to the body portion 421.

[0034] With the first insulator 61 and the second insulator 62 attached to the tooth core 4, among each of the teeth 42, the tip on the side opposite to the inner cylinder part 41 side is not covered by the insulator 6 and is in contact with the yoke core 5.

[0035] The tooth covering part 64 of the first insulator 61 extends from the left side part to the right side of the cylinder body 63 of the first insulator 61. Also, the tooth covering part 64 of the second insulator 62 extends from the right side part to the left side of the cylinder body 63 of the second insulator 62, but does not reach up to the tooth covering part 64 of the first insulator 61. That is, the tooth covering part 64 of the first insulator 61 and the tooth covering part 64 of the second insulator 62 are not in contact with each other, and a gap 65 is formed between them, and the teeth 42 are exposed at this part. However, since the coil wire 22 is wound so as to extend in the facing direction of the tooth covering part 64 of the first insulator 61 and the tooth covering part 64 of the second insulator 62 and straddle this gap 65, the coil wire 22 does not contact the teeth 42.

[0036] In addition, when the number of steel plates 40 constituting the tooth core 4 is changed due to a design change or the like of the motor 1, etc., the thickness of the tooth core 4 changes, but the distance between the first insulator 61 and the second insulator 62 changes along with the change in the thickness of the tooth core 4. Of course, it is also possible to configure so that the tooth covering part 64 of the first insulator 61 and the tooth covering part 64 of the second insulator 62 are in contact with each other and no gap is formed between them.

[0037] As shown in FIGS. 3 and 4, the yoke core 5 includes a plurality of steel plates 50. The yoke core 5 is formed by laminating a plurality of steel plates 50 in the thickness direction. Each steel plate 50 is formed of a magnetic material. Each steel plate 50 is, for example, a silicon steel plate.

[0038] As shown in FIG. 1, the shape of the yoke core 5 is cylindrical, and its central axis coincides with the central axis 320 of the output shaft 32. The yoke core 5 is attached to a plurality of teeth 42 and surrounds the plurality of teeth 42.

[0039] The yoke core 5 has a plurality (nine) of fitting portions 51. That is, the yoke core 5 has the same number of fitting portions 51 as the teeth 42. Each of the plurality of fitting portions 51 is a recess provided on the inner peripheral surface of the yoke core 5. The plurality of fitting portions 51 correspond one-to-one with the plurality of teeth 42. Each of the plurality of fitting portions 51 and the tooth 42 corresponding to this fitting portion 51 among the plurality of teeth 42 are fitted together by at least one of them moving in the radial direction of the inner cylinder portion 41. Thereby, the yoke core 5 is attached to the plurality of teeth 42.

[0040] A portion including two tip pieces 422 of the teeth 42 is fitted into each fitting portion 51. Therefore, the length of each fitting portion 51 in the circumferential direction of the yoke core 5 is equal to the length between the protruding tip of one of the two tip pieces 422 protruding from the body portion 421 and the protruding tip of the other tip piece 422. In this specification, "equal" is not limited to the case where a plurality of values completely coincide with each other, but also includes the case where they are different within an allowable error range. For example, it also includes the case where there is an error within 3%, 5%, or 10%.

[0041] With the insulator 6 attached to the tooth core 4 and the coil wire 22 wound around it, the yoke core 5 is attached to a plurality of teeth 42, for example, by shrink fitting. That is, with the yoke core 5 heated and expanded radially, the tooth core 4 is disposed inside the yoke core 5. As a result, the inner surface of the yoke core 5 faces the tips of the plurality of teeth 42 in the radial direction of the inner cylinder portion 41 with a slight gap between the inner surface of the yoke core 5 and the plurality of teeth 42. Then, when the temperature of the yoke core 5 decreases and the yoke core 5 contracts, the inner surface of the yoke core 5 contacts the tips of the plurality of teeth 42. That is, as the yoke core 5 contracts, the plurality of fitting portions 51 move radially inward of the yoke core 5, so that the plurality of fitting portions 51 and the plurality of teeth 42 are fitted together. The yoke core 5 applies a radial inward contact pressure to the plurality of teeth 42.

[0042] As shown in FIGS. 3 and 4, the stator 2 has a circuit board 7. The circuit board 7 supplies current to the stator wiring 21. The circuit board 7 has electrical components to be mounted, and motor terminals 71 that are electrically connected to the electrical components and to which the jumper wiring 23 is electrically connected. As shown in FIG. 3, the motor terminals 71 are provided on a part of the surface 200 of the stator core 20 where the jumper wiring 23 is disposed so as to protrude more than its peripheral portion. In the present embodiment, the motor terminals 71 are provided so as to protrude from the surface 60 of the second insulator 62. Three motor terminals 71 are provided, and each motor terminal 71 corresponds to the U-phase, V-phase, and W-phase of three-phase alternating current, respectively.

[0043] As shown in FIGS. 8 and 9, the motor terminal 71 has a pair of clamping pieces 711. The jumper wiring 23 is located between the two clamping pieces 711 and joined to the clamping pieces 711.

[0044] As shown in FIGS. 3 and 4, a board 72 different from the circuit board 7 is provided along the surface opposite to the surface 60 of the second insulator 62.

[0045] Next, the details of the configuration of the rotor 3 will be described. As shown in FIG. 3, the rotor core 30 of the rotor 3 includes a plurality of steel plates 301. The rotor core 30 is formed by laminating a plurality of steel plates 301 in the thickness direction. Each steel plate 301 is formed of a magnetic material. Each steel plate 301 is, for example, a silicon steel plate.

[0046] The rotor core 30 is formed in a cylindrical shape concentric with the inner cylindrical portion 41 of the stator core 20, and its central axis coincides with the central axis 320 of the output shaft 32. In the direction of the central axis 320, the positions of both ends of the rotor core 30 are substantially aligned with the positions of both ends of the stator core 20. Note that the positions of both ends of the rotor core 30 and the positions of both ends of the stator core 20 do not necessarily exactly overlap, and may be offset within an allowable error range. For example, there may be an offset within 3%, 5%, or 10% of the thickness of the rotor core 30.

[0047] The output shaft 32 is held inside the rotor core 30. The rotor core 30 includes a plurality (six in FIG. 1) of magnet accommodating portions 302. The plurality of magnet accommodating portions 302 accommodate a plurality of permanent magnets 31. Each of the plurality of magnet accommodating portions 302 is a through hole that penetrates the rotor core 30 in the direction of the central axis 320. Each of the plurality of permanent magnets 31 is held in the magnet accommodating portion 302 by being inserted into the magnet accommodating portion 302 with an adhesive attached. Note that each of the plurality of permanent magnets 31 may be held in the magnet accommodating portion 302 by the magnetic attraction force between the rotor core 30 without using an adhesive.

[0048] The plurality of magnet accommodating portions 302 are provided at equal intervals in the circumferential direction of the rotor core 30. As a result, the plurality of permanent magnets 31 are arranged at equal intervals in the circumferential direction of the rotor core 30. Also, the longitudinal direction of each of the plurality of permanent magnets 31 is along the circumferential direction of the rotor core 30. Each permanent magnet 31 is, for example, a neodymium magnet.

[0049] As shown in FIG. 3, the motor 1 further includes a base 35, a first bearing 33, and a second bearing 34. The base 35 is attached to the rotor core 30 and rotates integrally with the rotor core 30, the output shaft 32, and the inner ring of the first bearing 33. The first bearing 33 is disposed on the left side of the rotor core 30, and its inner ring is attached to the left-side portion of the output shaft 32. The second bearing 34 is disposed on the right side of the rotor core 30. The inner ring of the second bearing 34 is attached to the right-side portion of the output shaft 32 and rotates integrally with the output shaft 32, and the outer ring of the second bearing 34 is attached to the second insulator 62.

[0050] As shown in FIG. 1, in the manufacturing process of the motor 1, with the tooth core 4 of the stator 2 and the yoke core 5 separated, the coil wire 22 is wound around the body portions 421 of the plurality of teeth 42 of the tooth core 4 via the insulator 6. Thereafter, the yoke core 5 is attached to the plurality of teeth 42.

[0051] The coil wire 22 is wound around the teeth 42, for example, using a tool disposed on the tip side of each tooth 42. Since the plurality of teeth 42 protrude outward in the radial direction from the inner cylindrical portion 41, the space on the tip side of each tooth 42 can be widened as compared with the case where the plurality of teeth 42 protrude inward. Therefore, the coil wire 22 can be easily wound around each tooth 42, and in some cases, it is possible to increase the occupation ratio of the coil wire 22.

[0052] In addition, since each tooth 42 includes two tip pieces 422 that suppress the coil wire 22 from falling off the body portion 421, the coil wire 22 can be more easily wound around each tooth 42. Further, the stress applied to each tooth 42 can be dispersed to the two tip pieces 422, so the possibility of the tooth 42 deforming can be reduced. Further, the tip piece 422 includes a curved surface 44, and the curved surface 44 contacts the yoke core 5. Therefore, when the yoke core 5 is attached to the plurality of teeth 42, the stress applied from the yoke core 5 to each tooth 42 is more likely to be dispersed along the curved surface 44 compared to the case where the surface of the tip piece 422 is formed in a planar shape.

[0053] Also, before the wiring 23 is connected to the motor terminal 71, a gap that opens in a direction away from the surface 60 of the second insulator 62 is formed between the two clamping pieces 711 (see FIG. 9), and the wiring 23 is inserted through this gap. With the wiring 23 inserted between the two clamping pieces 711, the clamping pieces 711 are caulked to close the gap, and the wiring 23 is electrically connected to the motor terminal 71.

[0054] (3) Characteristic configuration of the motor (3.1) Elastic deformation part As shown in FIG. 5B, the elastic deformation part 43 is formed in a part of the inner cylinder part 41 of the tooth core 4. The elastic deformation part 43 has less rigidity than other parts of the inner cylinder part 41 and is easily elastically deformed. As described above, in the manufacturing process of the motor 1, the yoke core 5 has the tooth core 4 fitted inside by shrink fitting or the like, and the yoke core 5 applies a radial inward contact pressure to the plurality of teeth 42. Also, each tooth 42 receives tension from the wiring 23. Due to these factors, the inner cylinder part 41 of the tooth core 4 receives a circumferential force, and in particular, is likely to receive a circumferential compressive force.

[0055] When there is no particular part in a part of the inner cylinder portion 41 that is more likely to elastically deform than other parts, when the inner cylinder portion 41 of the tooth score 4 receives a circumferential compressive force, there is a risk that a large deformation such as buckling may occur in any part. Such a large deformation is not determined which part of the inner cylinder portion 41 it will occur in, and it greatly impairs the roundness of the inner cylinder portion 41, and the magnetic field generated by the stator core 20 may not be generated as designed, which may have an adverse effect on the output of the motor 1. Therefore, in the present embodiment, an elastic deformation portion 43 is provided in a part of the inner cylinder portion 41 of the tooth score 4.

[0056] The elastic deformation portion 43 has a smaller elastic coefficient (elastic modulus) in the circumferential direction of the inner cylinder portion 41 than the other parts of the inner cylinder portion 41 other than the elastic deformation portion 43. The elastic coefficient follows the so-called Hooke's law.

[0057] By providing such an elastic deformation portion 43, when the inner cylinder portion 41 of the tooth score 4 receives a circumferential force, most of the deformation in the inner cylinder portion 41 becomes the deformation in the elastic deformation portion 43, and it becomes easier to control the deformation in the inner cylinder portion 41. As a result, even when the inner cylinder portion 41 receives a circumferential force, it is easy to suppress the roundness of the inner cylinder portion 41 from being impaired.

[0058] Also in the present embodiment, the elastic deformation portion 43 is formed in the connecting portion 410. In the inner cylinder portion 41, the connecting portion 410 has a smaller elastic coefficient in the circumferential direction than the portion where the teeth 42 are provided. Therefore, by forming the elastic deformation portion 43 in the connecting portion 410, it becomes easier to form the elastic deformation portion 43 in the inner cylinder portion 41.

[0059] Also, in the present embodiment, the elastic deformation portion 43 is formed only at one location on the inner cylinder portion 41. Note that the elastic deformation portion 43 may be formed at two or more locations on the inner cylinder portion 41. When the elastic deformation portion 43 is formed at two or more locations on the inner cylinder portion 41, when the inner cylinder portion 41 receives a circumferential force, it is not determined which elastic deformation portion 43 will deform the most, and it becomes more difficult to control the deformation of the inner cylinder portion 41 than when the elastic deformation portion 43 is formed at one location on the inner cylinder portion 41. Therefore, although the elastic deformation portion 43 may be formed at one or two or more locations on the inner cylinder portion 41, it is desirable that the elastic deformation portion 43 be formed at one location on the inner cylinder portion 41. Thus, in the present embodiment, by forming the elastic deformation portion 43 only at one location on the inner cylinder portion 41, it becomes easier to control the deformation of the inner cylinder portion 41 when the inner cylinder portion 41 receives a circumferential force.

[0060] Also, in the present embodiment, the elastic deformation portion 43 has a groove 431 extending along the axial direction (the direction of the central axis 320) of the inner cylinder portion 41. Thereby, when the inner cylinder portion 41 receives a circumferential compressive force, the groove 431 can serve as a shrinkage allowance in the circumferential direction of the inner cylinder portion 41, making it easier to control the deformation (shrinkage in the circumferential direction) of the inner cylinder portion 41.

[0061] Also, in the present embodiment, the groove wall portion 432 constituting the groove 431 is curved. Thereby, when the inner cylinder portion 41 receives a circumferential tensile force, the groove wall portion 432 can serve as an elongation allowance in the circumferential direction of the inner cylinder portion 41, making it easier to control the deformation (elongation in the circumferential direction) of the inner cylinder portion 41.

[0062] (3.2) Position of the crossover wiring As shown in FIG. 7, the jumper wiring 23 is located at the portion 46 inside the radial direction of the body portion 421. As described above, the tooth core 4 has a plurality of teeth 42 that project outward in the radial direction from the inner cylinder portion 41. One stator wiring 21 is wound around the body portion 421 of one tooth 42 to form the coil wire 22, and then crawls toward the adjacent tooth 42 to become the jumper wiring 23, and is wound around the body portion 421 of the adjacent tooth 42 to become the coil wire 22, and this is repeated until it is wound around all the teeth 42. Such an operation is easy to perform because the tooth core 4 has a configuration in which a plurality of teeth 42 project outward in the radial direction from the inner cylinder portion 41. That is, if the teeth are configured to project inward in the radial direction of the yoke core 5, it is difficult to form a wide space on the tip side of the teeth, and it is difficult to perform the operation of winding the stator wiring around the teeth. Therefore, in the present embodiment, since the teeth 42 are configured to project outward in the radial direction from the inner cylinder portion 41, the tip side of the teeth is opened and a wide space is easily formed, and the operation of winding the stator wiring 21 around the teeth 42 becomes easy.

[0063] Further, since the jumper wiring 23 is located at the portion 46 inside the radial direction of the body portion 421, the length of the jumper wiring 23 (the length of the stator wiring 21) is shorter compared to the case where the jumper wiring 23 is located at the portion 47 outside the radial direction of the body portion 421, the electric wire is reduced, and the joule loss is reduced.

[0064] Further, when the tooth core 4 is fitted into the yoke core 5, the jumper wiring 23 is less likely to be sandwiched between the yoke core 5 and the tooth core 4 compared to the case where the jumper wiring 23 is located at the portion 47 outside the radial direction of the body portion 421.

[0065] As shown in FIG. 6, the second insulator 62 has a holding portion 24 that holds the position of the jumper wiring 23. The holding portion 24 projects from the plate portion 66 along the cylindrical body 63 in a part of the circumferential direction of the cylindrical body 63. As shown in FIG. 7, the jumper wiring 23 is held by the outer peripheral surface of the holding portion 24, and the movement of the jumper wiring 23 in the radial inner direction is restricted. Thereby, the position of the jumper wiring 23 is held, and it is suppressed that the jumper wiring 23 moves and tension is generated in the jumper wiring 23, or the roundness of the inner cylinder portion 41 is impaired.

[0066] Also, as shown in FIG. 3, the side peripheral surface 25 of the plate portion 66 of the second insulator 62 can also function as a holding portion that holds the position of the jumper wiring 23.

[0067] (3.3) Guide Support Portion As shown in FIGS. 6 and 8, a guide support portion 26 projects from the peripheral portion of the motor terminal 71 on the surface 200 of the stator core 20 (the surface 60 of the second insulator 62).

[0068] As described above, the jumper wiring 23 is sandwiched between the two sandwiching pieces 711 of the motor terminal 71. When the jumper wiring 23 is led out from the motor terminal 71, it extends toward the side peripheral surface 25 (see FIG. 3) of the second insulator 62. At this time, as shown in FIGS. 8 and 9, the jumper wiring 23 may contact the edge of the bottom plate 712 of the motor terminal 71, and the jumper wiring 23 may be damaged. Therefore, in the present embodiment, the guide support portion 26 is provided. The guide support portion 26 supports the jumper wiring 23 electrically connected to the motor terminal 71 in a direction away from the surface 200 of the stator core 20. Thereby, it becomes difficult for the jumper wiring 23 to contact the edge of the bottom plate 712 of the motor terminal 71, and it becomes difficult for the jumper wiring 23 to be damaged.

[0069] Also, in the present embodiment, the guide support portion 26 is formed on both sides sandwiching the motor terminal 71 in the peripheral portion of the surface 200 of the stator core 20. Thereby, it becomes difficult for the jumper wiring 23 to contact both edges of the bottom plate 712 of the motor terminal 71, and the jumper wiring 23 is less likely to be damaged. Note that the guide support portion 26 may be provided on one side of both sides sandwiching the motor terminal 71 in the peripheral portion of the surface 200 of the stator core 20.

[0070] Also, in the present embodiment, the guide support portion 26 is formed on the surface 60 of the insulator 6. Thereby, since the guide support portion 26 is formed on the surface 60 of the insulator 6 that can be formed of a synthetic resin, the guide support portion 26 is easily formed.

[0071] (4) Modification Next, modification examples of the embodiment will be listed. The following modification examples may be realized in appropriate combinations.

[0072] The configuration of the rotor 3 can be arbitrarily changed. For example, the plurality of permanent magnets 31 are not limited to being arranged in a polygonal shape, and may be arranged in a spoke shape.

[0073] The number of the permanent magnets 31 is not limited to six, and may be two or more.

[0074] The rotor 3 may have an electromagnet instead of the permanent magnet 31.

[0075] The shape of the rotor core 30 as viewed from the direction of the central axis 320 of the rotor core 30 is not limited to a perfect circle, and may be, for example, circular or elliptical, and a shape provided with protrusions and depressions on the circumference.

[0076] The motor 1 is not limited to being provided in the power tool 10. The motor 1 may be provided in, for example, an electric bicycle or an electric assist bicycle.

[0077] The motor 1 may further have an adjustment part attached to the rotor 3. The shape of the adjustment part is, for example, a cylindrical weight, and the adjustment part is attached to the output shaft 32 of the rotor 3. By shaving a part of the adjustment part to change the weight and the center of gravity of the adjustment part, the weight balance of the rotor 3 can be adjusted. Alternatively, the weight balance of the rotor 3 may be adjusted by shaving a part of the rotor core 30. Alternatively, the weight balance of the rotor 3 may be adjusted by adjusting the position and amount of the adhesive attached to the rotor 3.

[0078] Each of the plurality of steel plates 40 and the plurality of steel plates 301 is preferably a single member in which each part is connected. Thereby, the number of parts of the motor 1 can be reduced as compared with the case where each steel plate 40 (or 600) is composed of a plurality of members.

[0079] The stator wiring 21 may be composed of a plurality of electric wires instead of a single electric wire.

[0080] (5) Summary As is clear from the above-described embodiment and its modifications, the motor (1) of the first aspect includes a stator (2) having a stator core (20) and a stator wiring (21), and a rotor (3) having magnets and rotating with respect to the stator core (20). The stator core (20) has a tooth core (4) and a yoke core (5). The tooth core (4) has a cylindrical inner cylinder part (41) in which the rotor (3) is arranged inside, and a plurality of teeth (42) including a body part (421) protruding outward in the radial direction of the inner cylinder part (41) from the inner cylinder part (41). The yoke core (5) is attached to the plurality of teeth (42) and forms a cylindrical shape surrounding the plurality of teeth (42). The stator wiring (21) has a coil wire (22) wound around the body part (421), and a cross wiring (23) that electrically connects the coil wires (22) wound around the plurality of body parts (421). The cross wiring (23) is located at a portion inside in the radial direction of the body part (421).

[0081] According to the first aspect, compared with the case where the jumper wiring (23) is located in the radially outer portion (47) of the body portion (421), the length of the jumper wiring (23) is shortened, the electric wire is reduced, and the Joule loss is reduced.

[0082] The second aspect can be realized by combination with the first aspect. In the second aspect, the stator core (20) further includes an insulator (6) that covers the tooth core (4).

[0083] The insulator (6) has a holding portion (24) that holds the position of the jumper wiring (23).

[0084] According to the second aspect, the position of the jumper wiring (23) is held, and it is suppressed that the jumper wiring (23) moves to generate tension in the jumper wiring (23) or the roundness of the inner cylinder portion (41) is impaired.

[0085] Regarding the configuration other than the first aspect, it is not an essential configuration of the motor (1) and can be appropriately omitted.

[0086] The third aspect can be realized by combination with the first or second aspect. The power tool (10) of the third aspect includes the motor (1) of the first or second aspect.

[0087] According to the third aspect, the length of the jumper wiring (23) of the motor (1) included in the power tool (10) is shortened, the electric wire is easily reduced, and the Joule loss is easily reduced.

Explanation of Reference Numerals

[0088] 1 Motor 10 Power Tool 2 Stator 20 Stator Core 21 Stator Wiring 22 Coil Wire 23 Jumper Wiring 24 Holding Portion 25 Side Peripheral Surface 3 Rotor 31 Permanent magnet 4 Tooth score 41 Inner cylinder part 42 Teeth 421 Barrel part 5 Yoke core 6 Insulator

Claims

1. A stator having a stator core and stator windings, A rotor having a magnet and rotating with respect to the stator core, And an insulator, The stator core has A tooth core having a cylindrical inner cylinder portion in which the rotor is disposed inside, and a plurality of teeth including a body portion protruding outward in the radial direction of the inner cylinder portion from the inner cylinder portion, A cylindrical yoke core attached to the plurality of teeth and surrounding the plurality of teeth, And has, The stator windings are A coil wire wound around the body portion, And a jumper wire for electrically connecting the plurality of coil wires wound around the plurality of body portions, The jumper wire is located in the inner portion in the radial direction of the body portion, The insulator covers the tooth core, The insulator has a cylindrical body formed concentric with the inner cylinder portion, a lid-shaped plate portion formed radially inward from one axial end portion of the body, and a holding portion that protrudes in the axial direction of the body from the plate portion along the body only in a part of the circumferential direction of the body and restricts the movement of the jumper wire inward in the radial direction, A motor.

2. An electric tool comprising the motor according to claim 1. An electric tool.

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