Electric chain saw

Abstract

To provide an electric work machine in which a motor can be miniaturized.SOLUTION: An electric work machine includes: a stator including a stator core, an insulator fixed to the stator core, and a coil mounted on the insulator; a rotor having a rotor cup at least part of which is disposed on the outer peripheral side of the stator, and a magnet fixed to the rotor cup; a stator base supporting the stator core; a rotor shaft at least part of which is disposed on the inside of the stator base, the rotor shaft rotating around the axis of rotation; an output part driven by the rotor; and a bearing disposed between the stator base and the rotor shaft, the bearing supporting the rotor shaft. In an axial direction of the axis of rotation, the bearing and at least part of the stator core overlap.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to an electric Chainsaw .

Background Art

[0002] In the technical field related to electric working machines, an electric working machine equipped with an outer rotor type motor as disclosed in Patent Document 1 is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an electric working machine, miniaturization of the motor is required. In particular, a technology that can achieve miniaturization of the axial dimension parallel to the rotation axis of the motor is desired.

[0005] The present disclosure aims to miniaturize the motor.

Means for Solving the Problems

[0006] According to a first aspect of the present disclosure, there is provided an electric working machine including a stator including a stator core, an insulator fixed to the stator core, and a coil attached to the insulator, a rotor including a rotor cup at least partially disposed on the outer peripheral side of the stator, a magnet fixed to the rotor cup, a stator base supporting the stator core, a rotor shaft at least partially disposed inside the stator base and rotating about a rotation axis, an output unit driven by the rotor, and a bearing disposed between the stator base and the rotor shaft and supporting the rotor shaft, wherein in the axial direction of the rotation axis, at least a part of the bearing overlaps with at least a part of the stator core.

[0007] According to a second disclosure, a stator includes a stator core, an insulator fixed to the stator core, and a coil attached to the insulator, a rotor having a rotor cup at least partially disposed on an outer peripheral side of the stator, and a magnet fixed to the rotor cup, a stator base that supports the stator core, a rotor shaft at least partially disposed inside the stator base and rotating about a rotation axis, an output unit driven by the rotor, a first bearing disposed between the stator base and the rotor shaft to support a first portion of the rotor shaft, and a second bearing disposed between the stator base and the rotor shaft to support a second portion of the rotor shaft, and an electric working machine is provided.

Effect of the Invention

[0008] According to the present disclosure, the motor is miniaturized.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

[0010] Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings, but the present disclosure is not limited to the embodiments. The components of the embodiments described below can be combined as appropriate. Also, some components may not be used.

[0011] In the embodiments, the terms “left”, “right”, “front”, “rear”, “upper”, and “lower” are used to describe the positional relationship of each part. These terms indicate the relative position or direction based on the center of the electric working machine.

[0012] The electric working machine has a motor. In the embodiments, the radial direction of the rotation axis AX of the motor is appropriately referred to as the radial direction. The direction parallel to the rotation axis AX of the motor is appropriately referred to as the axial direction. The direction around the rotation axis AX of the motor is appropriately referred to as the circumferential direction or the rotation direction.

[0013] In the radial direction, a position close to or approaching the rotation axis AX of the motor is appropriately referred to as the inner radial side, and a position far from or separated from the rotation axis AX of the motor in the radial direction is appropriately referred to as the outer radial side. A position or direction on one side in the axial direction is appropriately referred to as one axial side, and a position or direction on the other side in the axial direction is appropriately referred to as the other axial side. A position or direction on one side in the circumferential direction is appropriately referred to as one circumferential side, and a position or direction on the other side in the circumferential direction is appropriately referred to as the other circumferential side.

[0014] [First Embodiment] The first embodiment will be described. FIG. 1 is a diagram showing an electric working machine 1 according to this embodiment. In this embodiment, the electric working machine 1 is a lawn mower, which is a type of outdoor power equipment.

[0015] As shown in FIG. 1, the electric working machine 1 includes a housing 2, wheels 3, a motor 4, a cutting blade 5, a cutting box 6, a handle 7, and a battery mounting portion 8.

[0016] The housing 2 houses the motor 4 and the cutting blade 5. Each of the wheels 3, the motor 4, and the cutting blade 5 is supported by the housing 2.

[0017] The wheels 3 rotate in a state of being in contact with the ground. When the wheels 3 rotate, the electric working machine 1 can move on the ground. Four wheels 3 are provided.

[0018] The motor 4 is a power source of the electric working machine 1. The motor 4 generates a rotational force for rotating the cutting blade 5. The motor 4 is disposed above the cutting blade 5.

[0019] The cutting blade 5 is connected to the motor 4. The cutting blade 5 is the output part of the electric working machine 1 driven by the motor 4. The cutting blade 5 rotates around the rotation axis AX of the motor 4 by the rotational force generated by the motor 4. The cutting blade 5 faces the ground. With the wheels 3 in contact with the ground, when the cutting blade 5 rotates, the grass growing on the ground is cut. The grass cut by the cutting blade 5 is stored in the cutting box 6.

[0020] The handle 7 is held by the hand of the user of the electric working machine 1. The user can move the electric working machine 1 while holding the handle 7 by hand.

[0021] The battery pack 9 is mounted on the battery mounting part 8. The battery pack 9 is the power source of the electric working machine 1. The battery pack 9 is detachable from the battery mounting part 8. The battery pack 9 includes a secondary battery. In the present embodiment, the battery pack 9 includes a rechargeable lithium-ion battery. The battery pack 9 can supply power to the electric working machine 1 when mounted on the battery mounting part 8. The motor 4 is driven based on the drive current supplied from the battery pack 9.

[0022] Each of FIGS. 2 and 3 is a perspective view showing the motor 4 according to the present embodiment. FIG. 2 is a perspective view from the upper side. FIG. 3 is a perspective view from the lower side. FIG. 4 is a longitudinal sectional view showing the motor 4 according to the present embodiment. The longitudinal sectional view is a sectional view including the rotation axis AX and parallel to the rotation axis AX. FIG. 5 is an exploded perspective view showing the motor 4 according to the present embodiment. FIG. 6 is a plan view of the motor 4 according to the present embodiment as viewed from below. In the present embodiment, the motor 4 is an outer rotor type brushless motor.

[0023] As shown in FIGS. 2, 3, 4, 5, and 6, the motor 4 includes a rotor 10, a rotor shaft 20, a stator 30, a stator base 40, and a sensor substrate 50. The rotor 10 rotates with respect to the stator 30. At least a part of the rotor 10 is disposed on the outer peripheral side of the stator 30. The rotor shaft 20 is fixed to the rotor 10. At least a part of the rotor shaft 20 is disposed inside the stator base 40. The rotor 10 and the rotor shaft 20 rotate about the rotation axis AX. The stator base 40 supports the stator 30. The stator base 40 is fixed to the stator core 31. The cutting blade 5 is connected to the rotor shaft 20. The cutting blade 5 is driven by the rotor 10. The sensor substrate 50 supports a magnetic sensor that detects the rotation of the rotor 10.

[0024] In the present embodiment, the rotation axis AX of the motor 4 extends in the vertical direction. The axial direction and the vertical direction are parallel. In the following description, one side in the axial direction is appropriately referred to as the upper side, and the other side in the axial direction is appropriately referred to as the lower side.

[0025] The rotor 10 has a rotor cup 11 and a magnet 12. The rotor cup 11 is made of a metal mainly composed of iron. The magnet 12 is a permanent magnet. At least a part of the rotor cup 11 is disposed on the outer peripheral side of the stator 30. The magnet 12 is fixed to the rotor cup 11.

[0026] The rotor cup 11 has a rotor yoke 13, a rotor plate 14, and a radial rib 15.

[0027] The rotor yoke 13 is cylindrical. The rotor yoke 13 is arranged to surround the stator 30. The rotor yoke 13 is arranged around the rotation axis AX. The central axis of the rotor yoke 13 coincides with the rotation axis AX. The rotor plate 14 is annular. The rotor plate 14 is arranged around the rotation axis AX. The central axis of the rotor plate 14 coincides with the rotation axis AX. At least a part of the rotor plate 14 faces the shaft end face 21 of the rotor shaft 20. The shaft end face 21 faces upward. The radial ribs 15 connect the rotor yoke 13 and the rotor plate 14. The radial ribs 15 extend radially outward from the rotor plate 14. A plurality of radial ribs 15 are provided at intervals in the circumferential direction. The rotor yoke 13, the rotor plate 14, and the radial ribs 15 are integral.

[0028] The magnets 12 are fixed to the rotor yoke 13. A plurality of magnets 12 are arranged in the circumferential direction. In the present embodiment, 14 magnets 12 are arranged in the circumferential direction. The N - pole magnets 12 and the S - pole magnets 12 are arranged alternately in the circumferential direction. In the present embodiment, the magnets 12 are arranged inside the rotor yoke 13. The magnets 12 are fixed to the inner surface of the rotor yoke 13 by, for example, an adhesive.

[0029] The rotor shaft 20 extends in the axial direction. The central axis of the rotor shaft 20 coincides with the rotation axis AX. The rotor shaft 20 is fixed to the rotor 10 such that the central axis of the rotor shaft 20 coincides with the central axis of the rotor yoke 13. The rotor shaft 20 has a shaft convex portion 22 that protrudes upward from the shaft end face 21. The rotor plate 14 has a shaft opening 16 in which the shaft convex portion 22 is arranged. By arranging the shaft convex portion 22 in the shaft opening 16, the rotor 10 and the rotor shaft 20 are positioned in the radial direction. By the contact between the shaft end face 21 around the shaft convex portion 22 and the lower surface of the rotor plate 14, the rotor 10 and the rotor shaft 20 are positioned in the axial direction.

[0030] In this embodiment, the rotor shaft 20 and the rotor plate 14 of the rotor 10 are fixed by rotor screws 23. A screw hole 24 is formed in the shaft end face 21. A screw opening 17 is formed in the rotor plate 14. With the shaft protrusion 22 disposed in the shaft opening 16, the rotor screw 23 is inserted into the screw hole 24 through the screw opening 17. The rotor 10 and the rotor shaft 20 are fixed by the rotor screw 23 by the engagement of the thread provided on the rotor screw 23 and the thread groove provided in the screw hole 24. In this embodiment, the rotor 10 and the rotor shaft 20 are fixed by three rotor screws 23.

[0031] The stator 30 includes a stator core 31, an insulator 32, and a coil 33.

[0032] The stator core 31 is made of a metal mainly composed of iron. The stator core 31 includes a stator yoke 34 and teeth 35. The stator yoke 34 is cylindrical. The stator yoke 34 is disposed around the rotation axis AX. The central axis of the stator yoke 34 and the rotation axis AX coincide. The teeth 35 protrude radially outward from the outer surface of the stator yoke 34. A plurality of teeth 35 are provided at intervals in the circumferential direction. In this embodiment, twelve teeth 35 are provided. Slots 36 are formed between adjacent teeth 35.

[0033] The insulator 32 is made of synthetic resin. The insulator 32 is fixed to the stator core 31.

[0034] The insulator 32 covers at least a part of the surface of the stator core 31. The insulator 32 covers at least a part of the end face of the stator yoke 34 facing the axial direction. The end face of the stator yoke 34 includes an upper end face facing upward and a lower end face facing downward. Also, the insulator 32 covers at least a part of the outer surface of the stator yoke 34 facing the radially outer side. Also, the insulator 32 covers at least a part of the surface of the teeth 35.

[0035] In this embodiment, the insulator 32 includes an upper insulator 321 fixed to the upper part of the stator core 31 and a lower insulator 322 fixed to the lower part of the stator core 31. The upper insulator 321 is mounted on the stator core 31 from above the stator core 31. The lower insulator 322 is mounted on the stator core 31 from below the stator core 31.

[0036] The coil 33 is mounted on the insulator 32. The coil 33 is wound around the teeth 35 via the insulator 32. The surface of the teeth 35 around which the coil 33 is wound is covered by the insulator 32. The outer surface of the teeth 35 facing the radially outer side is not covered by the insulator 32. The stator core 31 and the coil 33 are insulated by the insulator 32. A plurality of coils 33 are provided. In this embodiment, 12 coils 33 are arranged in the circumferential direction.

[0037] The sensor substrate 50 is fixed to the insulator 32. The sensor substrate 50 supports a magnetic sensor that detects the rotation of the rotor 10. The sensor substrate 50 is fixed to the insulator 32 such that the magnet 12 and the magnetic sensor face each other. The sensor substrate 50 is arranged radially outside the coil 33.

[0038] The stator base 40 supports the stator core 31. The stator base 40 is made of aluminum. The stator base 40 has a pipe portion 41, a leg portion 42, and a connecting rib portion 43.

[0039] The pipe portion 41 is substantially cylindrical. The pipe portion 41 is arranged around the rotation axis AX. The central axis of the pipe portion 41 and the rotation axis AX coincide.

[0040] At least a part of the pipe portion 41 is disposed inside the stator core 31. The central axis of the pipe portion 41 coincides with the central axis of the stator yoke 34. In the present embodiment, the pipe portion 41 includes a small-diameter portion 41A and a large-diameter portion 41B disposed below the small-diameter portion 41A. Each of the small-diameter portion 41A and the large-diameter portion 41B is cylindrical. The outer diameter of the large-diameter portion 41B is larger than the outer diameter of the small-diameter portion 41A. The central axis of the pipe portion 41 coincides with the rotation axis AX. The stator core 31 is disposed around the small-diameter portion 41A. The small-diameter portion 41A is disposed inside the stator core 31. The large-diameter portion 41B is disposed outside the stator core 31. The stator core 31 is fixed to the pipe portion 41. The stator base 40 is fixed to the stator 30 such that the central axis of the pipe portion 41 coincides with the central axis of the stator yoke 34.

[0041] The pipe portion 41 supports the rotor shaft 20 via the bearing 25. The rotor shaft 20 is disposed inside the pipe portion 41. The rotor shaft 20 is supported by the pipe portion 41 via the bearing 25. The bearing 25 is disposed between the stator base 40 and the rotor shaft 20. The bearing 25 is disposed between the inner surface of the pipe portion 41 and the outer surface of the rotor shaft 20. The bearing 25 rotatably supports the rotor shaft 20.

[0042] The bearing 25 includes an upper bearing 251 (first bearing) and a lower bearing 252 (second bearing) disposed below the upper bearing 251. The upper bearing 251 supports the first portion of the rotor shaft 20. The lower bearing 252 supports the second portion of the rotor shaft 20 below the first portion. Each of the upper bearing 251 and the lower bearing 252 is disposed between the pipe portion 41 of the stator base 40 and the rotor shaft 20.

[0043] In the axial direction, at least a part of the bearing 25 and the stator core 31 overlap. That is, in the axial direction, the position of the bearing 25 and the position of at least a part of the stator core 31 coincide. As described above, the bearing 25 includes an upper bearing 251 and a lower bearing 252. In the axial direction, one or both of the upper bearing 251 and the lower bearing 252 overlap with at least a part of the stator core 31. As shown in FIG. 4, in the present embodiment, in the axial direction, the upper bearing 251 overlaps with at least a part of the stator core 31. Note that, in the axial direction, the lower bearing 252 may overlap with at least a part of the stator core 31, or both the upper bearing 251 and the lower bearing 252 may overlap with at least a part of the stator core 31.

[0044] The upper bearing 251 has an upper end surface 253 (first end surface) facing upward and a lower end surface 254 (second end surface) facing downward. The rotor shaft 20 has a first support surface 28 that supports the upper end surface 253. The stator base 40 has a second support surface 413 that supports the lower end surface 254. The first support surface 28 faces downward. The second support surface 413 faces upward. At least a part of the outer surface of the rotor shaft 20 is provided with a stepped portion 29. The first support surface 28 includes the lower surface of the stepped portion 29 facing downward. The first support surface 28 contacts a part of the region radially inside of the upper end surface 253. At least a part of the inner surface of the pipe portion 41 is provided with a stepped portion 414. The second support surface 413 includes the upper surface of the stepped portion 414 facing upward. The second support surface 413 contacts a part of the region radially outside of the lower end surface 254. The inner surface of the upper bearing 251 facing radially inward contacts the outer surface of the rotor shaft 20. The outer surface of the upper bearing 251 facing radially outward contacts the inner surface of the pipe portion 41. The upper bearing 251 is sandwiched between the first support surface 28 and the second support surface 413 in the axial direction. The upper bearing 251 is sandwiched between the outer surface of the rotor shaft 20 and the inner surface of the pipe portion 41 in the radial direction. Thereby, the upper bearing 251, the rotor shaft 20, and the stator base 40 are positioned.

[0045] The lower bearing 252 has an upper end face 255 (the third end face) facing upward and a lower end face 256 (the fourth end face) facing downward. The stator base 40 has a third support surface 415 that supports the upper end face 255. The third support surface 415 faces downward. A stepped portion 416 is provided on at least a part of the inner surface of the pipe portion 41. The third support surface 415 includes the lower surface of the stepped portion 416 facing downward. The third support surface 415 contacts a part of the radially outer region of the upper end face 255. A circlip 27 that supports the lower end face 256 is attached to the rotor shaft 20. A groove 200 is formed in a part of the outer surface of the rotor shaft 20. At least a part of the circlip 27 is disposed inside the groove 200. The circlip 27 contacts a part of the radially inner region of the lower end face 256. The inner surface of the lower bearing 252 facing radially inward contacts the outer surface of the rotor shaft 20. The outer surface of the lower bearing 252 facing radially outward contacts the inner surface of the pipe portion 41. The lower bearing 252 is sandwiched between the third support surface 415 and the circlip 27 in the axial direction. The lower bearing 252 is sandwiched between the outer surface of the rotor shaft 20 and the inner surface of the pipe portion 41 in the radial direction. Thereby, the lower bearing 252, the rotor shaft 20, and the stator base 40 are positioned.

[0046] In the present embodiment, the lower bearing 252 is fixed to the pipe portion 41 by bearing fixing screws 26. A screw boss 48 is provided at the lower end portion of the pipe portion 41. The bearing fixing screws 26 are inserted into screw holes provided in the screw boss 48. When the bearing fixing screws 26 are inserted into the screw holes of the screw boss 48 with the lower bearing 252 disposed inside the pipe portion 41, the head of the bearing fixing screw 26 contacts at least a part of the lower end face 256 of the lower bearing 252. Due to the contact between the head of the bearing fixing screw 26 and the lower bearing 252, the lower bearing 252 is fixed to the pipe portion 41.

[0047] The foot portion 42 is disposed outside the stator core 31. The foot portion 42 is annular. The foot portion 42 is plate-shaped. The central axis of the pipe portion 41 and the central axis of the foot portion 42 coincide. The foot portion 42 is fixed to a fixation target. As an example of the fixation target, the housing 2 that houses the motor 4 is illustrated. When the foot portion 42 is fixed to the fixation target, the motor 4 is fixed to the fixation target. The inner diameter of the foot portion 42 is larger than the outer diameter of the pipe portion 41. A screw opening 45 is provided in the foot portion 42. A screw (not shown) is disposed in the screw opening 45. The foot portion 42 and the fixation target are fixed by the screw disposed in the screw opening 45 being coupled to a screw hole provided in the fixation target.

[0048] The connection rib portion 43 connects the pipe portion 41 and the foot portion 42. The connection rib portion 43 extends radially outward from the outer surface of the pipe portion 41. A plurality of connection rib portions 43 are provided at intervals in the circumferential direction. In the present embodiment, four connection rib portions 43 are provided. In the present embodiment, the connection rib portion 43 connects the large-diameter portion 41B of the pipe portion 41 and the foot portion 42. The radially inner end portion of the connection rib portion 43 is fixed to the outer surface of the large-diameter portion 41B. The radially outer end portion of the connection rib portion 43 is fixed to the inner surface of the foot portion 42. The connection rib portion 43 connects the pipe portion 41 and the foot portion 42 such that the central axis of the pipe portion 41 and the central axis of the foot portion 42 coincide.

[0049] The stator 30 has a stator screw 37 that fixes the stator base 40 and the stator core 31. A screw opening 38 is formed in the stator core 31. The screw opening 38 of the stator core 31 is formed so as to penetrate the upper end surface and the lower end surface of the stator yoke 34. A screw hole 47 is formed in the end surface of the large-diameter portion 41B of the stator base 40 that faces upward.

[0050] The stator screw 37 is inserted into the screw opening 38 of the stator core 31 from the upper side of the stator core 31. The stator screw 37 is inserted into the screw hole 47 of the stator base 40 through the screw opening 38 of the stator core 31. By coupling the thread provided on the stator screw 37 and the thread groove provided in the screw hole 47, the stator core 31 and the stator base 40 are fixed by the stator screw 37. In the present embodiment, the stator core 31 and the stator base 40 are fixed by three stator screws 37.

[0051] Next, the operation of the motor 4 will be described. In the present embodiment, the motor 4 is a three-phase brushless motor. Each of the 12 coils 33 is assigned to one of the U (U-V) phase, V (V-W) phase, and W (W-U) phases. The drive current supplied from the battery pack 9 to the motor 4 includes a U-phase drive current, a V-phase drive current, and a W-phase drive current. The drive current from the battery pack 9 is supplied to the coil 33 via a bus bar (not shown). When the drive current is supplied from the battery pack 9 to the coil 33, a rotating magnetic field is generated in the stator 30. When a rotating magnetic field is generated in the stator 30, the rotor 10 and the rotor shaft 20 rotate about the rotation axis AX.

[0052] As described above, according to the present embodiment, in the axial direction, at least a part of the bearing 25 and the stator core 31 overlap. Thereby, an increase in the size of the motor 4 in the axial direction is suppressed.

[0053] Also, according to the present embodiment, both the upper bearing 251 and the lower bearing 252 are disposed between the pipe portion 41 of the stator base 40 and the rotor shaft 20. Thereby, an increase in the size of the motor 4 in the axial direction is suppressed.

[0054] The upper end surface 253 of the upper bearing 251 contacts the first support surface 28 of the rotor shaft 20. The lower end surface 254 of the upper bearing 251 contacts the second support surface 413 of the stator base 40. The upper bearing 251 is inserted into the inside of the pipe portion 41 from above the pipe portion 41 together with the rotor shaft 20 while being in contact with the first support surface 28, and is sandwiched between the first support surface 28 and the second support surface 413. Thereby, the upper bearing 251, the rotor shaft 20, and the stator base 40 are positioned.

[0055] The upper end surface 255 of the lower bearing 252 contacts the third support surface 415 of the stator base 40. The lower bearing 252 can be inserted into the inside of the pipe portion 41 from below the pipe portion 41 to contact the third support surface 415. After the lower bearing 252 is disposed inside the pipe portion 41, the circlip 27 is disposed in the groove 200, so that the lower bearing 252 is sandwiched between the third support surface 415 and the circlip 27 in the axial direction. Thereby, the lower bearing 252, the rotor shaft 20, and the stator base 40 are positioned.

[0056] A rotor screw 23 for fixing the rotor shaft 20 and the rotor plate 14 is provided. The rotor shaft 20 and the rotor 10 are easily fixed by the rotor screw 23.

[0057] The shaft convex portion 22 of the rotor shaft 20 is disposed in the shaft opening 16 of the rotor plate 14. Thereby, the rotor 10 and the rotor shaft 20 are positioned.

[0058] The rotor yoke 13, the rotor plate 14, and the radial rib 15 are integral. Thereby, a change in the relative position between the rotor yoke 13 and the magnet 12 fixed to the rotor yoke 13 and the rotor plate 14 and the rotor shaft 20 fixed to the rotor plate 14 is suppressed.

[0059] [Second Embodiment] The second embodiment will be described. In the following description, components that are the same as or equivalent to those in the above-described embodiment are denoted by the same reference numerals, and the description thereof will be simplified or omitted.

[0060] Each of FIGS. 7 and 8 is a perspective view showing the motor 4 according to the present embodiment. FIG. 7 is a perspective view from the upper side. FIG. 8 is a perspective view from the lower side. FIG. 9 is an exploded perspective view showing the motor 4 according to the present embodiment.

[0061] In the above-described first embodiment, the insulator 32 includes the upper insulator 321 and the lower insulator 322. In the present embodiment, the insulator 32 is integrally formed with the stator core 31. The insulator 32 is fixed to the stator core, for example, by insert molding.

[0062] In the present embodiment, the rotor cup 11 has a cylindrical rotor yoke 13B, a rotor plate 14B at least a part of which faces the shaft end face 21, a rotor ring 18 fixed to the rotor plate 14B via a connection rib 180, and a columnar rib 19 extending axially from the rotor ring 18. The rotor yoke 13B is formed, for example, by drawing. The rotor plate 14B, the connection rib 180, the rotor ring 18, and the columnar rib 19 are integral. The rotor yoke 13B and the rotor plate 14B are separate. The columnar rib 19 projects downward from the rotor ring 18. A plurality of columnar ribs 19 are provided at intervals in the circumferential direction. In the present embodiment, 14 columnar ribs 19 are provided.

[0063] FIG. 10 is an exploded perspective view showing the rotor 10 according to the present embodiment. The magnet 12 is disposed inside the rotor yoke 13B. The columnar rib 19 is inserted inside the rotor yoke 13B. The columnar rib 19 contacts the magnet 12. The columnar rib 19 is disposed between the magnets 12 adjacent to each other in the circumferential direction. The magnet 12 is positioned by the columnar rib 19.

[0064] The rotor yoke 13B and the rotary ring 18 are connected. The rotary ring 18 has a ring large-diameter portion 18A that contacts the upper end surface of the rotor yoke 13B and a ring small-diameter portion 18B that is disposed inside the rotor yoke 13B. With the upper end surface of the rotor yoke 13B and the ring large-diameter portion 18A in contact, the ring small-diameter portion 18B fits inside the rotor yoke 13B. The outer surface of the ring small-diameter portion 18B contacts the inner surface of the rotor yoke 13B. When the upper end surface of the rotor yoke 13B and the ring large-diameter portion 18A are in contact, the rotor yoke 13B and the rotary ring 18 are positioned in the axial direction. When the ring small-diameter portion 18B fits inside the rotor yoke 13B and the outer surface of the ring small-diameter portion 18B and the inner surface of the rotor yoke 13B are in contact, the rotor yoke 13B and the rotary ring 18 are positioned in the radial direction.

[0065] The rotary ring 18 has a ring convex portion 181 that protrudes downward from the lower end surface of the ring large-diameter portion 18A. The rotor yoke 13B has a ring concave portion 130 in which the ring convex portion 181 is disposed. When the ring convex portion 181 is disposed in the rotor yoke 13B, the rotor yoke 13B and the rotary ring 18 are positioned in the circumferential direction.

[0066] One ring convex portion 181 is provided. One ring concave portion 130 is provided. In the circumferential direction, at least a part of the boundary between the mutually adjacent magnets 12 overlaps with at least a part of the ring concave portion 130. That is, in the circumferential direction, the position of one columnar rib 19 and the position of the ring convex portion 181 coincide.

[0067] As described above, according to the present embodiment, the rotor yoke 13B and the rotor plate 14B are separate bodies. The rotor yoke 13B can be easily manufactured, for example, by drawing. The rotary ring 18 is fixed to the rotor plate 14B via a connection rib 180. A columnar rib 19 extends axially from the rotary ring 18. The magnets 12 are easily positioned by the columnar rib 19. Thereby, the productivity of the motor 4 is improved.

[0068] The rotary ring 18 has a large-diameter ring portion 18A that contacts the upper end surface of the rotor yoke 13B and a small-diameter ring portion 18B that is disposed inside the rotor yoke 13B. The contact between the upper end surface of the rotor yoke 13B and the large-diameter ring portion 18A positions the rotor yoke 13B and the rotary ring 18 in the axial direction. The small-diameter ring portion 18B fits inside the rotor yoke 13B, positioning the rotor yoke 13B and the rotary ring 18 in the radial direction.

[0069] The rotary ring 18 has a ring projection 181 that projects downward from the lower end surface of the large-diameter ring portion 18A. The rotor yoke 13B has a ring recess 130 in which the ring projection 181 is disposed. The ring projection 181 being disposed in the ring recess 130 positions the rotor yoke 13B and the rotary ring 18. Also, since the ring projection 181 projects downward from the lower end surface of the large-diameter ring portion 18A, an increase in the size of the rotary ring 18 in the radial direction is suppressed.

[0070] In the circumferential direction, at least a part of the boundary between the mutually adjacent magnets 12 overlaps with at least a part of the ring recess 130. That is, the ring recess 130 and the ring projection 181 are disposed at a position in the rotor 10 where the passage of magnetic flux is small. Thereby, a decrease in the performance of the motor 4 is suppressed.

[0071] FIG. 11 is a perspective view showing a part of a modified example of the rotor 10 according to the present embodiment. As shown in FIG. 11, a groove portion 131 may be provided on the inner surface of the rotor yoke 13B. The groove portion 131 is provided on the inner surface of the rotor yoke 13B so as to extend in the axial direction. At least a part of the columnar rib 19 being disposed inside the groove portion 131 positions the rotor yoke 13B, the rotary ring 18, and the magnet 12 in the circumferential direction.

[0072] FIG. 12 is a perspective view showing a part of a modification of the rotor 10 according to the present embodiment. As shown in FIG. 12, a protruding rib 132 may be provided on the inner surface of the rotor yoke 13B. The protruding rib 132 protrudes radially inward from the inner surface of the rotor yoke 13B. The magnet 12 is disposed inside the rotor yoke 13B. The protruding rib 132 is disposed between the magnets 12 adjacent to each other. The protruding rib 132 positions the rotor yoke 13B and the magnet 12 in the circumferential direction. Also, in the circumferential direction, the protruding rib 132 and the columnar rib 19 may be alternately arranged. That is, the protruding rib 132 may be disposed between the columnar ribs 19 adjacent to each other in the circumferential direction. Thereby, the rotor yoke 13B, the rotor ring 18, and the magnet 12 are positioned in the circumferential direction.

[0073] [Third Embodiment] The third embodiment will be described. In the following description, the same reference numerals are given to the components that are the same as or equivalent to those in the above-described embodiment, and the description thereof is simplified or omitted.

[0074] FIG. 13 is a perspective view showing the rotor 10 according to the present embodiment. FIG. 14 is an exploded perspective view showing the rotor 10 according to the present embodiment. In the present embodiment, the rotor yoke 13B has a first yoke portion 1301, a second yoke portion 1302, a third yoke portion 1303, and a fourth yoke portion 1304. Each of the first yoke portion 1301, the second yoke portion 1302, the third yoke portion 1303, and the fourth yoke portion 1304 is ring-shaped. The second yoke portion 1302 is connected to the first yoke portion 1301. The third yoke portion 1303 is connected to the second yoke portion 1302. The fourth yoke portion 1304 is connected to the third yoke portion 1303.

[0075] The first yoke part 1301 has a large-diameter yoke part 13C that contacts the upper end surface of the second yoke part 1302 and a small-diameter yoke part 13D that is disposed inside the second yoke part 1302. The second yoke part 1302 has a large-diameter yoke part 13C that contacts the upper end surface of the third yoke part 1303 and a small-diameter yoke part 13D that is disposed inside the third yoke part 1303. The third yoke part 1303 has a large-diameter yoke part 13C that contacts the upper end surface of the fourth yoke part 1304 and a small-diameter yoke part 13D that is disposed inside the fourth yoke part 1304.

[0076] The first yoke part 1301 has a yoke convex part 133 that protrudes downward from the lower surface of the large-diameter yoke part 13C of the first yoke part 1301. The second yoke part 1302 has a yoke concave part 134 where the yoke convex part 133 of the first yoke part 1301 is disposed. The yoke concave part 134 of the second yoke part 1302 is provided on the upper end surface of the second yoke part 1302.

[0077] Similarly, the second yoke part 1302 has a yoke convex part 133 that protrudes downward from the lower surface of the large-diameter yoke part 13C of the second yoke part 1302. The third yoke part 1303 has a yoke concave part 134 where the yoke convex part 133 of the second yoke part 1302 is disposed. The third yoke part 1303 has a yoke convex part 133 that protrudes downward from the lower surface of the large-diameter yoke part 13C of the third yoke part 1303. The fourth yoke part 1304 has a yoke concave part 134 where the yoke convex part 133 of the third yoke part 1303 is disposed.

[0078] When the large-diameter yoke portion 13C of the first yoke portion 1301 contacts the upper end surface of the second yoke portion 1302, the first yoke portion 1301 and the second yoke portion 1302 are positioned in the axial direction. The small-diameter yoke portion 13D of the first yoke portion 1301 is disposed inside the second yoke portion 1302, and when the inner surface of the second yoke portion 1302 contacts the outer surface of the small-diameter yoke portion 13D, the first yoke portion 1301 and the second yoke portion 1302 are positioned in the radial direction. When the yoke convex portion 133 of the first yoke portion 1301 is disposed in the yoke concave portion 134 of the second yoke portion 1302, the first yoke portion 1301 and the second yoke portion 1302 are positioned in the circumferential direction.

[0079] Similarly, the second yoke portion 1302 and the third yoke portion 1303 are positioned, and the third yoke portion 1303 and the fourth yoke portion 1304 are positioned.

[0080] As described above, the rotor yoke 13B may be composed of a plurality of yoke portions (1301, 1302, 1303, 1304). Each of the plurality of yoke portions (1301, 1302, 1303, 1304) is manufactured, for example, by drawing. By the rotor yoke 13B being composed of a plurality of yoke portions (1301, 1302, 1303, 1304), the loss due to eddy current is reduced.

[0081] The first yoke portion 1301 has a large-diameter yoke portion 13C that contacts the upper end surface of the second yoke portion 1302 and a small-diameter yoke portion 13D that is disposed inside the second yoke portion 1302. When the large-diameter yoke portion 13C of the first yoke portion 1301 contacts the upper end surface of the second yoke portion 1302, the first yoke portion 1301 and the second yoke portion 1302 are positioned in the axial direction. The small-diameter yoke portion 13D of the first yoke portion 1301 is disposed inside the second yoke portion 1302, and when the inner surface of the second yoke portion 1302 contacts the outer surface of the small-diameter yoke portion 13D of the first yoke portion 1301, the first yoke portion 1301 and the second yoke portion 1302 are positioned in the radial direction.

[0082] The first yoke portion 1301 has a yoke convex portion 133 that protrudes axially from the large-diameter yoke portion 13C, and the second yoke portion 1302 has a yoke concave portion 134 in which the yoke convex portion 133 is disposed. When the yoke convex portion 133 is disposed in the yoke concave portion 134, the first yoke portion 1301 and the second yoke portion 1302 are positioned.

[0083] [Other Embodiments] In the above-described embodiment, the electric working machine 1 is assumed to be a lawn mower, which is a type of gardening tool. The gardening tool is not limited to a lawn mower. Examples of the gardening tool include a hedge trimmer, a chainsaw, a grass cutter, and a blower. Further, the electric working machine 1 may be an electric tool. Examples of the electric tool include a driver drill, a vibration driver drill, an angle drill, an impact driver, a grinder, a hammer, a hammer drill, a multi-tool, and a reciprocating saw.

[0084] In the above-described embodiment, a battery pack mounted on the battery mounting portion is used as the power source of the electric working machine. A commercial power source (alternating current power source) may be used as the power source of the electric working machine.

Description of Reference Numerals

[0085] 1... Electric working machine, 2... Housing, 3... Wheel, 4... Motor, 5... Cutting blade, 6... Cutting box, 7... Handle, 8... Battery mounting part, 9... Battery pack, 10... Rotor, 11... Rotor cup, 12... Magnet, 13... Rotor yoke, 13B... Rotor yoke, 13C... Large-diameter part of yoke, 13D... Small-diameter part of yoke, 14... Rotor plate, 14B... Rotor plate, 15... Radial rib, 16... Shaft opening, 17... Opening for screw, 18... Rotary ring, 18A... Large-diameter part of ring, 18B... Small-diameter part of ring, 19... Columnar rib, 20... Rotor shaft, 21... Shaft end face, 22... Shaft convex part, 23... Rotor screw, 24... Screw hole, 25... Bearing, 26... Bearing fixing screw, 27... Circlip, 28... First support surface, 29... Step part, 30... Stator, 31... Stator core, 32... Insulator, 33... Coil, 34... Stator yoke, 35... Teeth, 36... Slot, 37... Stator screw, 38... Opening for screw, 40... Stator base, 41... Pipe part, 41A... Small-diameter part, 41B... Large-diameter part, 42... Foot part, 43... Connecting rib part, 45... Opening for screw, 47... Screw hole, 48... Screw boss, 50... Sensor board, 130... Ring recess, 131... Groove part, 132... Protruding rib, 133... Yoke convex part, 134... Yoke concave part, 180... Connecting rib, 181... Ring convex part, 200... Groove, 251... Upper bearing, 252... Lower bearing, 253... Upper end face, 254... Lower end face, 255... Upper end face, 256... Lower end face, 321... Upper insulator (first insulator), 322... Lower insulator (second insulator), 413... Second support surface, 414... Step part, 415... Third support surface, 416... Step part, 1301... First yoke part, 1302... Second yoke part, 1303... Third yoke part, 1304... Fourth yoke part, AX... Rotation axis.

Claims

【Claim 1】 A stator core having a stator yoke and twelve teeth protruding radially outward from the outer surface of the stator yoke, An insulator made of synthetic resin integrally formed with and fixed to the stator core by insert molding, A stator including a coil wound around the teeth via the insulator, A stator base for supporting the stator, A cylindrical rotor yoke arranged to surround the stator, Fourteen magnets fixed to the rotor yoke at intervals in the circumferential direction by an adhesive, A rotor including a rotor shaft at least partially disposed inside the stator base, rotated about a rotation axis, and integrally rotated with the rotor yoke, An annular rotor plate having a shaft opening in which the rotor yoke and the rotor shaft are disposed and connected to the rotor shaft, and a plurality of connection ribs extending radially outward from the peripheral edge of the rotor plate and provided at equal intervals in the circumferential direction, the dimension in the circumferential direction being smaller than that of the magnet, and connecting the rotor yoke and the rotor plate, A blade portion driven by the rotor, A first bearing and a second bearing disposed between the stator base and the rotor shaft and supporting the rotor shaft, A sensor substrate supporting a magnetic sensor for detecting the rotation of the rotor, The first bearing supports a first portion of the rotor shaft in the axial direction of the rotation axis and overlaps at least a part of the stator core, The second bearing supports a second portion of the rotor shaft, The rotor yoke is composed of a plurality of yoke portions arranged in the axial direction, and the adjacent yoke portions in the axial direction are connected to each other, The sensor substrate is disposed between the stator base and the stator core and fixed to the insulator. Electric chain saw. Claim 2 A plurality of yoke convex portions disposed on the rotor yoke are disposed in a plurality of yoke concave portions disposed on the rotor yoke. The electric chain saw according to claim 1. Claim 3 Screws are disposed in a plurality of screw openings provided in the legs of the stator base, and the stator base and the object to be fixed are fixed by the screws. The electric chain saw according to claim 1. Claim 4 The sensor substrate is disposed radially outside the coil in a part around the rotation axis. The electric chain saw according to claim 1.

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