WO2020170824A1 - Electric work machine - Google Patents

Abstract

[Problem] To provide an electric work machine comprising a brushless motor having excellent a heat dissipation property. [Solution] A lawn mower, as an example of this electric work machine, is provided with: a main body housing 10; a motor case 22 arranged inside the main body housing 10; a stator 23 that is held by the motor case 22 and has a stator core 40, coils 45, and insulating parts 44 interposed between the stator core 40 and the coils 45; a brushless motor 21 arranged inside the stator 23 and provided with a rotor 24 having a rotary shaft 25; and a spindle 17 driven by the rotary shaft 25. The stator 23 has coil outside resins 36 which are resins making contact with the outsides of the coils 45 and the stator core 40.

Description

Electric work machine

The present invention relates to an electric power tool, a gardening tool such as a lawn mower, and an electric working machine such as an air compressor for an air tool.

A brushless motor is used as a power source in the vibration driver drill, which is the electric tool disclosed in Japanese Unexamined Patent Application Publication No. 2017-7068 (Patent Document 1).
When driven, the brushless motor generates heat in the coil, the stator core, the rotor core, and the like.

JP, 2017-7068, A

When the brushless motor accumulates heat, the operation of the brushless motor may be affected. Therefore, it is preferable that heat be radiated.
A main object of the present invention is to provide an electric working machine equipped with a brushless motor having excellent heat dissipation.

According to a first aspect of the present invention, there is provided a stator having a stator core, a coil, and an insulator interposed between the stator core and the coil, which is held in a case, and a rotor arranged inside the stator and having a rotating shaft. A brushless motor provided and an output unit driven by the rotating shaft are provided, and the stator includes a coil outside resin that is a resin that contacts the outside of the coil and at least one of the case and the stator core. It is characterized by having.
According to a second aspect of the present invention, in the above invention, a plurality of the coils are provided, and the resin on the outside of the coils is arranged in series so as to commonly contact the outside of each of the plurality of the coils. It is a feature.
According to a third aspect of the present invention, in the above invention, a plurality of the coils are provided, and the resin outside the coil has a groove formed between each of the plurality of the coils. It is a thing.
According to a fourth aspect of the present invention, in the above invention, the case is made of a non-magnetic metal.
The invention according to claim 5 is characterized in that, in the above invention, the resin on the outside of the coil has fins.
According to a sixth aspect of the present invention, in the above-described invention, the coil outer resin covers all exposed electric materials in the stator.
According to a seventh aspect of the present invention, in the above invention, the case has a ventilation port.
The invention according to claim 8 is characterized in that, in the above-mentioned invention, the resin on the outside of the coil is a silicone resin.
According to a ninth aspect of the present invention, in the above-mentioned invention, the stator core has a plurality of teeth that respectively project inward, a plurality of the coils are provided, and the coils are wound around the teeth via the insulator. The resin outside the coil does not cover the protruding end portion of each tooth.
According to a tenth aspect of the present invention, in the above invention, the case has a case fin.
According to an eleventh aspect of the present invention, in the above invention, the case fin is provided on an outer peripheral surface of the case.
According to a twelfth aspect of the present invention, in the above-mentioned invention, the case fin is tapered.
The invention according to claim 13 is characterized in that, in the above-mentioned invention, a plurality of the case fins are provided and are alternately arranged.
According to a fourteenth aspect of the present invention, in the above-mentioned invention, the case fin is oblique to the rotation shaft of the brushless motor.
According to a fifteenth aspect of the present invention, in the above invention, the case fin is provided on a thrust surface of the case.
The invention according to claim 16 is characterized in that, in the above-mentioned invention, the case fins extend radially.
According to a seventeenth aspect of the present invention, in the above-mentioned invention, a plurality of the case fins are provided and concentrically project in a cylindrical shape.
According to an eighteenth aspect of the present invention, in the above-mentioned invention, the case fin extends in a spiral shape that gradually approaches the outer edge from the central portion.
According to a nineteenth aspect of the present invention, in the above-mentioned invention, the case fin is divided in the circumferential direction.
According to a twentieth aspect of the present invention, there is provided a stator which is held in a case and has a stator core, a coil, and an insulator interposed between the stator core and the coil, and a rotor which is arranged inside the stator and has a rotating shaft. A brushless motor provided, an output unit driven by the rotating shaft, and a fan driven by the rotating shaft are provided, and the case has an outer wall and an inner wall, and the brushless motor is provided in the inner wall. A motor and the fan are held, and the wind from the fan passes between the outer wall and the inner wall.
According to a twenty-first aspect of the present invention, in the above-mentioned invention, the case has a ventilation port.

The main effect of the present invention is to provide an electric working machine equipped with a brushless motor having excellent heat dissipation.

It is a center longitudinal cross-sectional view of the lawnmower which concerns on the 1st form of this invention. It is a partially expanded view of FIG. It is a perspective view of the motor unit in the lawn mower of FIG. It is a disassembled perspective view of the motor unit of FIG. It is a longitudinal cross-sectional view of the motor unit of FIG. It is a cross-sectional view of the upper case portion in the motor unit of FIG. It is a cross-sectional view of the lower case portion in the motor unit of FIG. It is explanatory drawing of the steel plate and split mold of a stator core in the motor unit of FIG. It is a perspective view of the brushless motor in the motor unit of FIG. It is a top view of the stator in the motor unit of FIG. FIG. 11 is a bottom view of the stator of FIG. 10. FIG. 11 is a perspective view of a short-circuit member in the stator of FIG. 10 (only the first to third fittings are shown by solid lines). FIG. 13 is a view similar to FIG. 12 in which the direction of the viewpoint is changed. It is a disassembled perspective view of the short circuit member of FIG. It is explanatory drawing of the winding method of the coil in the stator of FIG. FIG. 13 is a top view showing a connection state of the first to third fittings in the short-circuit member of FIG. 12. FIG. 17 is a wiring circuit diagram by the first to third fittings of FIG. 16. It is explanatory drawing corresponded to FIG. 6 of the lawnmower which concerns on the 2-1st form of this invention. It is explanatory drawing corresponded to FIG. 6 of the lawn mower which concerns on the 2-2nd form of this invention. It is explanatory drawing corresponded to FIG. 6 of the lawnmower which concerns on the 2nd-3rd form of this invention. FIG. 6 is a view corresponding to FIG. 5 of the lawn mower according to Embodiment 3-1 of the present invention, in which (A) the coil outside resin is not shown, and (B) the end surface of the coil outside resin is shown by hatching. FIG. 6 is a view corresponding to FIG. 5 of the lawnmower according to the third to second aspects of the present invention, in which (A) the coil outside resin is not shown, and (B) the end surface of the coil outside resin is shown by hatching. A lawn mower according to (A) 1st form, (B) 4-1 form, (C) 4-2 form, (D) 4-3 form, and (E) 4-4 form of the present invention. It is explanatory drawing (partially expanded view) of the side view shape of the fin in a motor case. Top view shapes of fin groups in the motor case of the lawn mower according to (A) 1st form, (B) 5-1 form, (C) 5-2 form, and (D) 5-3 form of the present invention. FIG. (A) 5-4th embodiment, (B) 5-5th embodiment, (C) 5-6th embodiment, (D) 5-7th embodiment, (E) 5-8th embodiment, (F) of the present invention ) It is an explanatory view of a top view shape of a fin group in the motor case of the lawn mower according to the fifth to ninth aspects. It is a longitudinal section explanatory view of a motor unit of a lawn mower concerning the 6th form of the present invention. It is (A) partial center longitudinal cross-section explanatory drawing of the grinder which concerns on the 7th form of this invention, (B) (A) AA line cross-section explanatory drawing. It is a partial center longitudinal cross-sectional explanatory view of (A) of the impact driver which concerns on 8th form of this invention, (B) BB line sectional explanatory drawing of (A).

Embodiments of the present invention and modifications thereof will be described below with reference to the drawings as appropriate.
The front, rear, upper, lower, left, and right in the form and the modified example are determined for convenience of description, and may change depending on the work situation, the state of moving members, and the like.
The present invention is not limited to the following modes and modifications.

[First form]
FIG. 1 is a central longitudinal sectional view of a rechargeable lawnmower 1 which is an example of an electric working machine (gardening tool) according to a first embodiment of the present invention. FIG. 2 is a partially enlarged view of FIG.
The lawn mower 1 includes a base 2 that extends in the front-rear direction and has an open lower surface, a main body 3 that is connected to the upper center of the base 2, and a frame-shaped handle 4 that extends rearward and obliquely upward from the rear portion. There is. The direction is based on the user holding the handle 4, the left side of FIG. 1 is in front of the lawn mower 1, and the upper side of FIG. 1 is on the lawn mower 1.

The base 2 has a pair of wheels 5 on the front and the rear, respectively, and can be moved back and forth by a handle 4.
A rear cover 6 and a grass basket 7 are provided below the handle 4 at the rear end of the base 2.
A switch lever 8 is provided at the rear end of the handle 4, and a lock-off button 9 that normally locks the operation of the switch lever 8 is provided in front of the switch lever 8. When the lock-off button 9 is pushed to unlock the switch lever 8, the switch lever 8 can be pulled.

The main body 3 has a main body housing 10 as an outer housing in which a cylindrical portion 11 at the lower end that opens downward is projected into the base 2. On the upper part of the main body housing 10, a battery mounting portion 12 into which a battery pack 13 as a power source can be inserted and mounted from the upper rear side is formed so as to be lowered frontward. The battery mounting portion 12 can be opened and closed by a battery cover 14.
A controller 15 having a control circuit board (not shown) is supported on the front of the main body housing 10 in a vertically standing state. The control circuit board includes a microcomputer and a plurality (12) of switching elements.
A motor unit 16 is provided behind the controller 15 and below the battery mounting portion 12. A rotary shaft 25 of the brushless motor 21 projects downward from the motor unit 16, and a spindle 17 is coaxially connected to the lower end of the rotary shaft 25. The spindle 17 projects downward from the tubular portion 11 in the base 2, and a horizontal plate-shaped cutting blade 20 is attached to the lower end of the spindle 17 by an inner flange 18 and a bolt 19 in an orthogonal manner. Yes (output section).

As shown in FIGS. 3 and 4, the motor unit 16 has a brushless motor 21 and a motor case 22 that holds the brushless motor 21.
The brushless motor 21 is an inner rotor type that includes a cylindrical stator 23 and a rotor 24 that penetrates the inside of the stator 23 and has a rotating shaft 25 at its axis.
The motor case 22 has an upper case 26 and a lower case 27 that hold the stator 23 from above and below and rotatably support the rotating shaft 25. The lower case 27 is attached to a base 28 provided on the upper side of the tubular portion 11. A motor cover 29 that covers the motor unit 16 from above is provided on the upper side of the base 28.
On the other hand, below the base 28, a bearing retainer 30 that rotatably supports the spindle 17 via a bearing 31 is assembled by a plurality of screws 32 from below. The lower end of the spindle 17 penetrating the bearing retainer 30 penetrates the baffle plate 33 screwed to the lower end of the tubular portion 11 and projects into the base 2.
The inner flange 18 on which the cutting blade 20 is mounted is provided with a cylindrical portion 34 into which the lower end of the spindle 17 is fitted. A centrifugal fan 35 is provided on the outer circumference of the cylindrical portion 34. An exhaust port (not shown) is arranged in a portion of the main body housing 10 radially outside the centrifugal fan 35. The centrifugal fan 35 may be an axial fan or the like, or may be omitted.

The stator 23 of the brushless motor 21, which is also shown in FIG. 4 or FIG. 7, has a plurality of steel plates 40a (FIG. 8) stacked in the axial direction, and a stator core 40 having a plurality of (12) teeth 41 protruding inside. An upper insulator 42 and a lower insulator 43 as resin-made electric insulating members integrally formed on both upper and lower ends of the stator core 40, and an inner peripheral surface of the stator core 40 and protruding end surfaces of each tooth 41 are integrally formed continuously with these. It includes a resin-made insulating portion 44 that covers the outer peripheral surface except for, and a coil 45 that is wound around each tooth 41 through the insulating portion 44.
Further, a coil outside resin 36 is provided to commonly cover the outer peripheral surface of the coil 45 wound around each tooth 41. Here, the coil outside resin 36 is provided by integrally molding the coil outside resin 36 on the stator core 40 around which the coil 45 is wound (resin mold). The coil outside resin 36 is a silicon resin (heat-conducting non-magnetic material) having good heat conductivity. Further, the coil outer side resin 36 does not cover the protruding end portion of each tooth 41, but spreads between each tooth 41. The coil outside resin 36 may be a resin other than the silicone resin. The coil outer side resin 36 may cover the protruding end portions of the teeth 41. Further, the coil outside resin 36 may be arranged in a state where a part of the coil 45 is exposed.
The upper insulator 42 is assembled with a short circuit member 46 that is electrically connected to a wire that forms the coil 45 to form a three-phase connection, and a sensor circuit board 47 that detects the rotational position of the rotor 24.

On the circumferential surface of the stator core 40, three protrusions 48A, 48A, 48B are formed at equal intervals in the circumferential direction.
The ridges 48A, 48A have a tapered cross-sectional shape in which the width in the circumferential direction becomes smaller toward the radially outer side of the stator core 40.
The ridge 48B is not tapered and has a quadrangular cross-sectional shape whose circumferential width does not change along the radial direction. A slight R (curved surface) that bulges outward along the circumferential direction is provided on the radially outer end surface of the protrusion 48B.
Further, through holes 49 are formed in the protrusions 48A, 48A and 48B, respectively.

As shown in FIG. 8, the protrusions 48A, 48A, 48B are formed by overlapping the protrusions 50A, 50A, 50B formed on each steel plate 40a.
Each of the protrusions 50A is formed in a taper shape in which the width in the circumferential direction becomes smaller toward the radially outer side of the stator core 40.
The protrusion 50B is not tapered and has a rectangular cross-sectional shape whose circumferential width does not change along the radial direction. A slight R (curved surface) that bulges outward along the circumferential direction is provided on the radially outer end edge of the protrusion 50B.
A through hole 49 is formed in each of the protrusions 50A, 50A and 50B.
A notch 52 is formed between each of the protrusions 50A, 50A, 50B. Due to the notch 52, a groove 53 for positioning the stator 23 at the time of manufacturing is formed between the protrusions 48A, 48A, 48B.

Since each protrusion 48A has a tapered shape, interference with the mold is prevented when the upper insulator 42, the lower insulator 43, and the insulating portion 44 are integrally molded.
That is, when the upper insulator 42, the lower insulator 43, and the insulating portion 44 are integrally molded with the stator core 40 by the left and right split molds 54 shown by the two-dot chain line in FIG. By positioning the two ridges 48A, 48A on the left and right, the ridges 48A, 48A do not interfere with the split mold 54 that moves in the left-right direction in FIG. 8 due to the tapered surface. The taper angle θ with respect to this operation direction is 3° here. In addition, R that bulges outward is given to the end surface of the protrusion 48B. Therefore, interference with the left and right split molds 54 is prevented. The angle θ is not limited to 3°, and may be set appropriately within the range of 1° to 10°.

The rotor 24 has a cylindrical rotor core 55 in which a plurality of steel plates 40a are laminated in the axial direction, and a rotating shaft 25 penetrating the axial center thereof. The rotor core 55 and the rotary shaft 25 are integrally formed of resin 56. A chamfer 57 (FIG. 4) is formed at the lower end of the rotary shaft 25.
On the outer circumference of the rotary shaft 25, a twill knurl 25a is formed in the resin 56 filling area as a rotary shaft stopper and a rotary shaft slip stopper, and minute irregularities are formed on the outer peripheral surface of the rotary shaft 25 in a grid pattern. It is formed into a shape.
A plurality of (eight) magnet holes 58 are concentrically formed through the periphery of the rotor core 55 in the axial direction, and a plate-shaped permanent magnet 59 is embedded in each magnet hole 58. Inside each of the permanent magnets 59, a space portion 60 as a meat steal is formed by stacking through holes formed in the steel plate 40a excluding the upper and lower ends, and the weight of the rotor 24 is reduced.

The upper case 26 and the lower case 27 of the motor case 22 have a circular cup shape that covers the upper and lower portions of the stator 23, respectively.
The upper case 26 is made of a non-magnetic metal such as an aluminum alloy, and as shown in FIGS. 3 to 5, a plurality of fins 65 for heat radiation in the vertical direction are provided in the circumferential direction from the outer circumference of the upper surface to the side surfaces. It is erected at a predetermined interval. The upper case 26 is formed here by die casting (die casting), and each fin 65 has a taper shape in which the width increases (the thickness decreases) as it goes upward in order to facilitate the removal of the die. .. The upper case 26 may be made of other material such as resin.
An upper bearing holding portion 66 is formed in the center of the upper surface of the upper case 26, and a bearing 68 is held via a resin insulating cap 67 to support the upper end of the rotary shaft 25. A through hole 69 is formed at the center of the upper bearing holding portion 66 and is closed by a resin cap 70.
Further, on the peripheral surface of the upper case 26, three screw boss portions 71A, 71A, 71B that bulge outward in the radial direction are formed at equal intervals in the circumferential direction in the vertical direction. The screw boss portions 71A, 71A, 71B correspond to the protrusions 48A, 48A, 48B of the stator core 40, and the lower ends of the screw boss portions 71A, 71A, 71B are cross-sections that are fitted to the protrusions 48A, 48A, 48B in order. The opening is tapered or rectangular in cross section. A slit 72 is formed upward from the lower end between the protrusions 48A, 48A, 48B on the peripheral surface of the upper case 26.

The lower case 27 is similar to the upper case 26, and has a circular end surface portion 73 in which a lower bearing holding portion 74 is formed in the center, and a cylindrical portion 75 that rises upward from the outer periphery of the end surface portion 73. .. A bearing 76 is held by the lower bearing holding portion 74 and supports the rotating shaft 25 penetrating the lower bearing holding portion 74. On the outer periphery of the tubular portion 75, a plurality of (four places) bosses 77 for screwing the base 28 are formed downward at equal intervals in the circumferential direction.
Further, from the inner surface of the end surface portion 73 to the inner circumference and outer circumference of the tubular portion 75, the inner surface of the end surface portion 73 excluding the lower bearing holding portion 74 and the inner circumference of the tubular portion 75 and the outer circumference excluding each boss 77 are included. Is formed continuously. Boss portions 79A, 79A, 79B having the same shape as the corresponding screw boss portions 71A, 71A, 71B of the upper case 26 are formed in the resin layer 78 at positions corresponding to the protrusions 48A, 48A, 48B of the stator core 40 in the axial direction. Has been done. The upper ends of the boss portions 79A, 79A, 79B are provided with through holes that are tapered in the cross section or square in the cross section and are fitted into the ridges 48A, 48A, 48B, respectively. Further, concave grooves 80 are continuously formed below the bosses 79A, 79A, 79B.

The upper case 26 of the motor case 22 is covered with the screw boss portions 71A, 71A, 71B of the stator core 40 from above the stator 23 so as to fit the screw boss portions 71A, 71A, 71B, and is attached to the upper end of the rotary shaft 25 of the rotor 24. The bearing 68 is held by the upper bearing holding portion 66.
On the other hand, the lower case 27 covers the protrusions 48A, 48A, 48B of the stator core 40 with the bosses 79A, 79A, 79B from below the stator 23, and the bearing 76 mounted on the lower end of the rotary shaft 25. It is held by the lower bearing holding portion 74.
In this state, screws 81 are inserted into the boss portions 79A, 79A, 79B of the lower case 27 from below, pass through the protrusions 48A, 48A, 48B, and reach the screw boss portions 71A, 71A, 71B of the upper case 26. Can be put in. Then, the brushless motor 21, that is, the motor unit 16 covered with the upper case 26 and the lower case 27 except for a part of the outer periphery of the stator core 40 is obtained.

The brushless motor 21 is provided with basic insulation by a basic insulating member (an upper insulator 42, a lower insulator 43 and an insulating portion 44 which are integrally molded) interposed between a stator core 40 which is an internal metal and a coil 45 which is a charging portion. Given.
Further, a resin 56 as a rotary shaft side insulating member interposed between the rotary shaft 25 and the rotor core 55, an insulating cap 67 interposed between the upper case 26 and the rotary shaft 25, and a cylinder of the lower case 27. Additional insulation is provided by the resin layer 78 interposed between the shaped portion 75 and the stator core 40.
Therefore, the stator core 40 and the rotating shaft 25 are doubly insulated.
Further, since a vertical gap is formed between the upper case 26 and the lower case 27, the stator 23 can be assembled even if the axial dimension of the stator 23 changes.

The motor unit 16 is fixed to the base 28 by placing a screw in each boss 77 from below the base 28 in a state where the motor unit 16 is placed on the base 28 with the rotating shaft 25 facing downward. On the lower surface of the end surface portion 73 of the lower case 27, a pair of concentric circular arc ribs 73a for fitting the tubular portion 11 and positioning the motor unit 16 are formed (FIGS. 2 and 5).
The motor cover 29 covering the motor unit 16 covers the motor unit 16 in a state where the central portion including the upper bearing holding portion 66 of the upper case 26 is exposed. The fins 65 of the upper case 26 are close to the inner surface of the motor cover 29.
The stator 23 of the brushless motor 21 includes a screw 81 penetrating the ridges 48A, 48A, 48B and screw boss portions 71A, 71A, 71B of the upper case 26 and the lower case 27 which are fitted to the ridges 48A, 48A, 48B. The boss portions 79A, 79A, 79B prevent the motor case 22 from rotating.

As shown in FIGS. 9 and 10, the upper insulator 42 is a ring body integrally formed with the upper end surface of the stator core 40, and a plurality (12 pieces) of the short-circuit member 46 (12 pieces) provided on the upper surface thereof are provided on the upper surface thereof. Terminal holding portions 85 for holding the fusing terminals 99 are provided at equal intervals in the circumferential direction.
Each terminal holding portion 85 is formed by vertically arranging an inner wall portion 86 on the inner peripheral side and an outer wall portion 87 on the outer peripheral side with a gap substantially corresponding to the diameter of the wire 115 in the radial direction. A fitting groove 88 for fitting the fusing terminal 99 is formed in the center of the outer wall portion 87 and the outer wall portion 87 in the circumferential direction.
Further, on the upper surface of the insulator 42, a plurality of stop bosses 89 for assembling the short-circuit member 46 (five places) are provided in a protruding manner at positions where they come into contact with the bases of the teeth 41 at every other position.
As shown in FIG. 11, the lower insulator 43 is a ring body integrally formed with the lower end surface of the stator core 40, and the lower surface thereof is circumferentially displaced from the root of each tooth 41. A plurality of (12) guide walls 90 extending in the direction are erected.

The short-circuit member 46 is a resin ring body that is slightly smaller than the upper insulator 42, and has a plurality of (five) rectangular tubular members that fit into the stopper bosses 89 of the upper insulator 42 from above on the outer periphery thereof. The fitting boss 95 and a plurality of (three) ribs 96 that engage with the grooves 53 of the stator core 40 are provided in a protruding manner.
Further, as shown in FIGS. 12 to 14, the short-circuit member 46 is formed in a step-like shape in which the axial thickness gradually decreases from the upper surface from the outer circumference to the inner circumference. , The maximum diameter of the first metal fitting 97U located in the outermost part of the wall thickness, the second metal fitting 97W of the intermediate diameter located in the middle part of the inner wall thickness, and the minimum diameter located in the inner peripheral part of the inner wall The third metal fitting 97V and the third metal fitting 97V are arranged concentrically and are insert-molded. In addition, U, W, and V in a part of reference numerals mean that they are related to the U phase, W phase, and V phase of the corresponding three-phase currents, respectively.

The first to third metal fittings 97U to 97V are band plates having a “C” shape in a top view, and project outward in the radial direction at a plurality (4) of both end portions and point symmetrical positions of the both end portions. A protruding piece 98 is formed. A fusing terminal 99 is formed at the tip of each protruding piece 98. The fusing terminal 99 is once bent downward, folded back upward, and further bent outward.
A welding portion 101 for spot welding the power supply line 100U is formed at the base of the protruding piece 98 at one end of the first metal fitting 97U, and is opposite to the first metal fitting 97U of the second and third metal fittings 97W, 97U. Welded portions 101 for spot welding the power supply wires 100W and 100V are also formed at the bases of the protruding pieces 98 at the end portions on the side.

The first to third metal fittings 97U to 97V are arranged in the short-circuit member 46 in the order of the first metal fitting 97U, the second metal fitting 97W, and the third metal fitting 97V from the top and with a phase shift of a predetermined angle in the circumferential direction. Has been done. The fusing terminals 99 project from the outer peripheral surface of the short-circuit member 46 in which the first to third metal fittings 97U to 97V are insert-molded, in a non-contact state with each other and at substantially equal intervals in the circumferential direction.
A plurality of (three places) through holes 102 are formed in the short-circuit member 46 in a state in which they are biased to a part in the circumferential direction at predetermined intervals. In each through hole 102, the corresponding welded portion 101 of the first to third metal fittings 97U to 97V is exposed. A corresponding power supply line 100U to 100V is spot-welded to each welding portion 101. A state in which a cutout 103 for pulling out the power supply lines 100U to 100V is connected between the welded portion 101 of the first metal fitting 97U and the welded portion 101 of the third metal fitting 97V, and only the lower side of the short-circuit member 46 is connected. Is formed by.
Further, a plurality of (a pair of) supporting pieces 104 provided with mounting bosses 105 for mounting the sensor circuit board 47 are provided at the point symmetrical positions on the inner circumference of the short-circuit member 46 so as to protrude toward the center side. A plurality of receiving pieces 106 (FIG. 13) supporting the outer circumference of the sensor circuit board 47 are provided between the support pieces 104 and on the inner circumference of the short-circuit member 46 so as to protrude toward the center.

The sensor circuit board 47 is a strip plate shape that circulates in an arc shape inside the short-circuit member 46, and fitting holes 107 into which the mounting bosses 105 of the respective support pieces are fitted are formed at both ends in the circumferential direction. .. The sensor circuit board 47 is held on the inner peripheral side of the short-circuit member 46 by fitting the mounting boss 105 into each fitting hole 107 and supporting the outer circumference by the receiving piece 106.
A plurality of (three) rotation detecting elements 108 (FIG. 11) such as Hall elements that detect the magnetic field of the permanent magnet 59 of the rotor 24 are mounted on the back surface of the sensor circuit board 47.
A plurality of (five) signal lines 109 and power supply lines 100U to 100V connected to the sensor circuit board 47 are drawn out from the cutout 103 of the short-circuit member 46. This pulled-out position corresponds to the slit 72 provided in the upper case 26 of the motor case 22.

The short-circuit member 46 is attached to the stator 23 together with the sensor circuit board 47. At this time, the five fitting bosses 95 on the outer circumference fit into the stopper bosses 89 on the upper surface of the upper insulator 42. Further, the screws 91 (FIG. 10) are inserted into the respective stop bosses 89 from above. Further, the tips of the three ribs 96 engage with the grooves 53 of the stator core 40. Further, each fusing terminal 99 is held by each terminal holding portion 85 of the upper insulator 42.
In particular, the rib 96 engages with and bites into the groove 53 at a plurality of (3) locations, and thus functions as an anchor that stably supports the short-circuit member 46.
The power supply lines 100U to 100V and the signal line 109 are drawn out from the slit 72 of the upper case 26 through the packing 82 (FIG. 3) on the sleeve attached to the slit 72.

Each coil 45 is wound using three winding nozzles as shown in FIG.
That is, starting from the three teeth 41 located at 120° intervals, the wires 115A, 115B, 115C fed from the corresponding winding nozzles start to be wound at the same time, and then directly to the four teeth 41 adjacent to the stator 23 in the circumferential direction. Each of them is wound in order to form a total of 12 coils 45.
In the wire 115A, after the starting end 116A is locked to the fusing terminal 99 corresponding to the first tooth 41, the coil 45 is sequentially formed on the tooth 41 adjacent in the clockwise direction. The winding direction at this time is a counterclockwise direction toward the tooth 41. In addition, the crossover 117A after the formation of each coil 45 is returned to the upper insulator 42 (connection side) and locked to the fusing terminal 99 between the pair of adjacent teeth 41.
Then, when the fourth coil 45 is formed, as shown in FIG. 11, the wire 115A is once pulled out to the side of the lower insulator 43 (the side opposite to the wire connection side), and at the base of the wound tooth 41. After being wound on the guide wall 90 from the outside, it is returned to the upper insulator 42 side again, and the starting end 116B of another adjacent wire 115B is locked to the fusing terminal 99 to be locked, and the locking portion ends. 118A. The direction of the terminal end 118A is aligned with the direction of the starting end 116B of another adjacent wire 115B, and can be simultaneously cut in the circled portion of FIG.
The wires 115B and 115C are wound in the same manner as the wire 115A except for the arrangement. The orientation of the terminal end 118B of the wire 115B is aligned with the orientation of the starting end 116C of the wire 115C, and the orientation of the terminal end 118C of the wire 115C is aligned with the orientation of the starting end 116A of the wire 115A.

The first to third metal fittings 97U to 97V of the short-circuit member 46 are arranged in a state in which the coils 45 are out of phase with each other in the circumferential direction, and as shown in FIG. The predetermined crossovers 117A to 117C are each fusing with three coils 45 interposed therebetween. In FIG. 16, the first metal fitting 97U is hatched and the second metal fitting 97W is shaded in order to easily distinguish the crossovers 117A to 117C to which the first to third metal fittings 97U to 97V are fused. , 3rd metal fitting 97V is dotted.
The three coils 45 that are continuously adjacent to each other in the circumferential direction are delta as U (WU), V (UV), and W (UW) by the first to third metal fittings 97U to 97V of each phase. Wired. Then, since these are arranged in parallel in the order of 4 sets by the first to third metal fittings 97U to 97V, the three-phase circuit here is as shown in FIG. This three-phase circuit is equivalent to a delta connection in which four coils U1 to U4, V1 to V4, and W1 to W4 of U, V, and W phases are connected in parallel.

Next, an operation example of such a lawnmower 1 will be described.
When the operator pushes the lock-off button 9 and then pulls the switch lever 8 with two charged battery packs 13 mounted in the battery mounting portion 12, the main switch is turned on, The ON signal is transmitted to the control circuit board of the controller 15.
The microcomputer of the control circuit board that has received the ON signal acquires the rotation state of the rotor 24 based on the detection signal obtained from the rotation detection element 108 of the sensor circuit board 47, and controls ON/OFF of each switching element according to the acquired rotation state. Then, the rotor 24 is rotated by sequentially supplying an exciting current to the coils 45 of the respective phases of the stator 50.
Due to the rotation of the rotor 24, the rotary shaft 25 rotates, and a rotational force is applied to the cutting blade 20 via the spindle 17. Therefore, the lawnmower 1 performs an operation of mowing lawn by the cutting blade 20 that is rotated horizontally (parallel to the ground) around the vertical axis (rotary blade type).
The operator pushes the base 2 forward through the handle 4 to cause the lawnmower 1 to travel on the lawn-grown ground through the wheels 5 and trims the lawn to prepare the lawn surface. The mowed grass is collected in the grass collection basket 7.

At this time, in the brushless motor 21, the stator 23 is prevented from rotating with respect to the motor case 22 assembled to the base 28 by the screw 81 penetrating the protrusions 48A, 48A, 48B serving as a rotation preventing portion, and therefore, it depends on the tolerance. The influence is small, and the rotation can be stopped with high accuracy. Further, when fixing the brushless motor 21, high strength can be obtained. In particular, since the screw 81 directly penetrates the stator core 40, bending is less likely to occur as compared with the structure in which the upper case 26 and the lower case 27 are connected to each other outside the stator core 40 by a screw.
Further, since the wires 115A to 115C forming the coil 45 do not intersect with each other, abrasion due to contact is less likely to occur and durability is improved.
Further, in the rotor 24, since the twill knurls 25a are provided on the outer periphery of the rotating shaft 25, the biting of the resin 56 is improved, the slip torque in the rotation direction and the axial direction is increased, and the rotation of the cutting blade 20 causes a load. Even if the value becomes large, the integrity of the rotary shaft 25 and the rotor core 55 is maintained.

Further, the rotation of the rotating shaft 25 causes the centrifugal fan 35 to rotate and push out the surrounding air radially outward, so that the centrifugal force is passed from the outside of the main body 3 through the gap, the gap of the motor cover 29, and the outside of the motor unit 16 to the centrifugal force. A flow of air (wind) reaching the fan 35 and the exhaust port of the main body housing 10 radially outside thereof is formed.
The wind cools the internal mechanism of the lawnmower 1.

Further, in the stator core 40 of the brushless motor 21, since the coil outer resin 36 covering the coils 45 wound around the teeth 41 is provided, it is generated by the operation of the brushless motor 21 including energization of the coils 45. The heat is transferred to the coil outside resin 36. The heat received by the coil outer side resin 36 is transmitted to the metal motor case 22 through the stator core 40 that is in direct contact therewith, and is dissipated from the fins 65 and the like of the motor case 22. The heat generated by the brushless motor 21 has a larger amount of heat transferred to the motor case 22 and is dissipated more efficiently than when the coil outer resin 36 is not provided.
As shown in FIG. 23(A), the wind W from above hits the tapered slopes of the fins 65, so that the motor case 22 and thus the brushless motor 21 are efficiently cooled.

Next, the operational effects that the lawnmower 1 can play will be described.
The lawn mower 1 is held by the motor case 22, and is provided with a stator core 40, a coil 45, and a stator 23 having an insulating portion 44 interposed between the stator core 40 and the coil 45, and is arranged inside the stator 23. A brushless motor 21 having a rotor 24 having 25 and a spindle 17 driven by a rotating shaft 25 are provided. The stator 23 has a coil outside resin 36 that is a resin that contacts the outside of each coil 45 and the stator core 40. Have. Therefore, the brushless motor 21 is efficiently radiated by the coil outside resin 36, the stator core 40, and the motor case 22, and the lawnmower 1 including the brushless motor 21 having excellent heat radiation is provided.
A plurality of coils 45 are provided, and the coil outside resin 36 is arranged in series so as to commonly contact the outside of each of the plurality of coils 45. Therefore, the coil outer side resin 36 is easier to form.
Further, the motor case 22 is made of non-magnetic metal. Therefore, the coil outside resin 36 is thermally coupled to the non-magnetic metal having excellent thermal conductivity via the stator core 40, and the heat dissipation is further enhanced.

[Modification Example of First Mode]
It should be noted that the present invention is not limited to the above-described first embodiment and its modified examples, and the following modifications may be made as appropriate.
The fins 65 may be prepared separately from the motor case 22 and fixed to the motor case 22. Fins for heat dissipation may be provided on the stator core 40. In this case, the motor case 22 or the fin 65 thereof may be omitted.
The motor case 22 may not be divided into upper and lower parts, may be divided into three or more parts, or may be omitted.
The teeth 41 and the coils 45 may be 11 or less or 13 or more. The circuit of the coil 45 may be a delta connection of 3 parallels or less or 5 parallels or more for each phase, a delta connection including series connection, or a star connection.

Further, for the purpose of improving the heat dissipation of the brushless motor 21, at least one of the following items may be performed together with the formation of the fins 65 or in place of the formation of the fins 65.
At least one of the upper insulator 42, the lower insulator 43, and the insulating portion 44 has a higher thermal conductivity (for example, 4. W/m·K (watt/meter/kelvin)) than that of a normal resin. It may be formed of a high thermal conductive resin having 7, 13 or 24 W/m·K).
At least one of the coil 45 and the stator core 40 or the motor case 22 and the stator core 40 and the motor case 22 is coated with a highly heat-conductive adhesive or a fluid silicone resin, or a high-heat conductive sheet is interposed. You may be dressed.
Fins may be provided on at least one of the inner wall of the motor case 22 and the portion of the main body housing 10 adjacent to the motor case 22.

A power cord is provided in place of the battery mounting portion 12 to drive a commercial power source, the number of various screws and screw holes is increased or decreased, various engaging portions, connecting portions, screw fastening portions, holding portions, And/or at least one of the mounting portions is changed to another structure or type, at least one of the microcomputer and the switching element is mounted on the sensor circuit board 47, and at least one of various cases and housings is made of material. At least one of various members, number of parts, presence/absence of installation, material, arrangement, structure, type, etc., such as resin, metal such as aluminum (including aluminum alloy), and composites thereof, etc. May be changed as appropriate.
Further, the present invention can be applied to other types of lawn mowers such as a reel blade type which is a cylindrical reel blade in which the cutting blade 20 rotates around the left-right direction as an axial direction, and thus to other electric working machines. May be applied. For example, the present invention is applied to high-power products, such as angle drills, hammers, hammer drills, marunoco, reciprocating saws or grinders in power tools, or chainsaws in gardening tools, hedge trimmers, blowers, mowers or hedge clippers, Alternatively, it is applied to an air compressor for air tools that uses air as a power source. An electric work machine, such as an air compressor for an air tool, for operating a work machine that performs work is included in the electric work machine.
The above-described effects of the present invention are particularly remarkable in a relatively large brushless motor (the outer diameter (diameter) of the stator core 120 is, for example, 80 mm or more).

[Second form]
The second form of the present invention is the same as the first form except for the form of the resin outside the coil. Such a second form includes a 2-1 form to a 2-3 form depending on the form of the resin on the outside of the coil. Members and portions similar to those in the first embodiment are designated by the same reference numerals, and description thereof will be appropriately omitted.

[Form 2-1]
FIG. 18 is an explanatory diagram corresponding to FIG. 6 of the lawnmower according to the 2-1st mode of the present invention.
The coil outer resin 236A of the stator 223A in the brushless motor 221A of the lawn mower is arranged at 12 positions so that the coil outside resin 236A individually contacts the outside of each of the 12 coils 45. And a tubular base part for connecting the parts). The base portion covers the inner surface of the stator core 40. Grooves P extending in the radial direction are formed in portions of the coil outside resin 236A between the adjacent coils 45, respectively.

The lawn mower according to the 2-1st mode is held inside the motor case 22, has a stator core 40, a coil 45, and a stator 223A having an insulating portion 44 interposed between the stator core 40 and the coil 45, and the inside of the stator 223A. And a spindle 17 that is driven by the rotating shaft 25, and the stator 223A is a resin that contacts the outside of each coil 45 and the stator core 40. 236A of each coil outer side resin. Therefore, the brushless motor 221A is efficiently radiated by the coil outside resin 236A, the stator core 40 and the motor case 22, and a lawn mower provided with the brushless motor 221A having excellent heat radiation is provided.
Further, twelve coils 45 are provided, and each coil outside resin 236A has a groove P formed between twelve coils 45. Therefore, the heat transfer in each coil 45 is directed to the stator core 40 or the motor case 22 by each coil outer side resin 236A, and the heat transfer property is enhanced.

[Type 2-2]
FIG. 19 is an explanatory diagram corresponding to FIG. 6 of the lawnmower according to the second to second aspects of the present invention.
The coil outside resin 236B of the stator 223B in the brushless motor 221B of the lawn mower is arranged in series so as to commonly contact the outside of each of the plurality of coils 45, and at the upper and lower portions of each coil 45, It has a fin 237 that projects upward or downward in the shape of a plate that extends in the radial direction.

The lawn mower according to the second to second aspects includes a stator 223B that is held by the motor case 22, has a stator core 40, a coil 45, and an insulating portion 44 that is interposed between the stator core 40 and the coil 45, and the inside of the stator 223B. And a spindle 17 driven by the rotation shaft 25, and the stator 223B is made of resin that contacts the outside of the coil 45 and the stator core 40. It has a certain coil outside resin 236B. Therefore, the brushless motor 221B is efficiently radiated by the coil outer side resin 236B, the stator core 40 and the motor case 22, and the lawn mower provided with the brushless motor 221B having excellent heat radiation is provided.
The coil outer side resin 236B has each fin 237. Therefore, the surface area of the coil outer side resin 236B is efficiently increased, and the heat dissipation of the brushless motor 221B is further improved.

[Type 2-3]
FIG. 20 is an explanatory diagram corresponding to FIG. 6 of the lawnmower according to the second to third aspects of the present invention.
The coil outer side resin 236C of the stator 223C in the brushless motor 221C of the lawn mower is arranged at 12 positions so that the coil outside resin 236C individually contacts the outside of each of the 12 coils 45, and their roots (radial outside). And a tubular base part for connecting the parts). Grooves P extending in the radial direction are formed in portions of the coil outside resin 236C between the adjacent coils 45, respectively. Further, fins 237 projecting in a plate shape extending in the radial direction upward or downward are formed at the portions above and below the coil 45 in each coil outside resin 236C.

The lawn mower according to the second to third aspects is a stator 223C that is held by the motor case 22, has a stator core 40, a coil 45, and an insulating portion 44 that is interposed between the stator core 40 and the coil 45, and the inside of the stator 223C. And a spindle 17 driven by the rotating shaft 25. The stator 223C is made of resin that contacts the outside of the coil 45 and the stator core 40. There is a certain coil outside resin 236C. Therefore, the brushless motor 221C is efficiently radiated by the coil outer side resin 236C, the stator core 40 and the motor case 22, and a lawn mower provided with the brushless motor 221C having excellent heat radiation is provided.
Further, twelve coils 45 are provided, and each coil outside resin 236C has a groove P formed between twelve coils 45. Therefore, the heat transfer in each coil 45 is directed to the stator core 40 or the motor case 22 by each coil outer resin 236C, and the heat transfer property is enhanced.
Further, each coil outside resin 236C has a fin 237. Therefore, the surface area of the coil outside resin 236C is efficiently increased, and the heat dissipation of the brushless motor 221C is further improved.

[Modification Example of Second Mode]
In addition, the said 2nd form has the same modification as the 1st form suitably.
In addition, in the 2-1 and 2-3 forms, at least a part of the base portion connecting the roots of the coil outer side resins 236A and 236C may be omitted. When all of the base portions are omitted, the coil outside resins 236A and 236C are arranged at 12 positions so as to individually contact the outside of each of the 12 coils 45. Moreover, each coil outer side resin 236A, 236C (individual part) may straddle a plurality of coils. The base portion of each coil outer side resin 236A, 236C may not cover the inner surface of the stator core 40.
Furthermore, in the 2nd, 2nd and 3rd configurations, the fin 237 may be formed only on one surface side of the coil outer side resin 236B, 236C, or may be arranged so as to be displaced from the coil 45. Alternatively, the fin 237 may be a metal plate and may be coupled to the coil outside resins 236B and 236C. Further, instead of the fin 237 or together with the fin 237, a metal disk contacting one surface of the coil outer side resin 236B, 236C may be coupled to at least one of the stator core 40 and the motor case 22.

[Third mode]
The third mode of the present invention is the same as the first mode except for the resin outside the coil and the motor case. Such a third form includes a 3-1 form and a 3-2 form depending on the form of the motor case. Members and portions similar to those in the first embodiment are designated by the same reference numerals, and description thereof will be appropriately omitted.

[Form 3-1]
FIG. 21(A) is a view corresponding to FIG. 5 of the lawn mower according to Embodiment 3-1 of the present invention, in which the resin outside the coil is not shown. FIG. 21(B) is a view corresponding to FIG. 5 of the lawn mower according to Embodiment 3-1 of the present invention, in which the end surface of the resin outside the coil is hatched.
The coil outside resin 336A of the stator 323A in the brushless motor 321A of the motor unit 316A of the lawn mower is cylindrical and is arranged in series so as to commonly contact the outside of each of the plurality of coils 45. It extends from the lower surface of the upper wall of the upper case 326A in 322A to the upper surface of the lower wall of the lower case 327A. The coil outside resin 336A is in contact with the inner surface of the peripheral wall of the upper case 326A and the inner wall of the lower case 327A. The coil outer resin 336A is integrally molded with the stator 223A after the stator 223A is assembled and before the rotor 24 is assembled when the motor unit 316A is assembled. The coil outside resin 336A is used for all the electric materials (electrically exposed ones, here, each coil 45, the wire portion wound around the guide wall 90, the crossovers 117A to 117C and the sensor circuit board 47, and all the electric materials in the stator 323A. The short-circuit member 46) including the fusing terminal 99 and the welded portion 101 is covered.
A ring-shaped high thermal conductor 338 is arranged between the upper case 326A and the lower case 327A of the motor case 322A and on the radially outer side of the stator core 40. The high thermal conductor 338 is made of silicon resin here, and has high thermal conductivity as a resin. The high thermal conductor 338 is in contact with the stator core 40 and the upper case 326A and the lower case 327A, has an outer surface continuous with the outer surface of the upper case 326A and the outer surface of the lower case 327A, and has a lower surface than the upper case 326A in the motor case 322A. It is designed to fill the step of the case 327A.

A lawn mower according to a 3-1st aspect is a stator 323A held by a motor case 322A, having a stator core 40, a coil 45, and an insulating portion 44 interposed between the stator core 40 and the coil 45, and the inside of the stator 323A. And a spindle 17 that is driven by the rotating shaft 25. The stator 323A includes the stator 323A outside the coil 45 and the stator core 40 and the motor case 322A. The coil outer resin 336A which is a resin that contacts the upper and lower inner surfaces (from the lower surface of the upper wall of the upper case 326A to the upper surface of the lower wall of the lower case 327A). Therefore, the brushless motor 321A is efficiently dissipated by the coil outer resin 336A that is in contact with the stator core 40 and the motor case 322A, and a lawnmower equipped with the brushless motor 321A having excellent heat dissipation is provided. Further, since all the electric material in the stator 323A is covered with the coil outer side resin 336A, the brushless motor 321A has waterproofness and dustproofness.
Further, the high thermal conductor 338 is arranged on the step (between the upper case 326A and the lower case 327A) of the motor case 322A. Therefore, as compared with the case where the high thermal conductor 338 is not arranged, the wind easily contacts the high thermal conductor 338, and the heat dissipation efficiency is further improved.
Further, the high thermal conductor 338 is in contact with the stator core 40. Therefore, the heat dissipation efficiency of the stator core 40 is further improved.

[3-2nd form]
FIG. 22(A) is a view corresponding to FIG. 5 of the lawn mower according to Embodiment 3-2 of the present invention, in which the resin outside the coil is not shown. FIG. 22(B) is a view corresponding to FIG. 5 of the lawnmower according to Embodiment 3-2 of the present invention, in which the end surface of the resin outside the coil is hatched.
The coil outside resin 336B of the stator 323B in the brushless motor 321B of the motor unit 316B of the lawn mower is cylindrical and is arranged in series so as to commonly contact the outside of each of the plurality of coils 45. It extends from a portion of the upper case 326B that is separated from the lower surface of the upper wall of the upper case 326B by a first predetermined distance to a portion of the upper wall of the lower case 327B that is separated from the upper surface of the lower wall by a second predetermined distance. That is, the coil outside resin 336B is formed in a state having a gap between itself and the inner surface of the motor case 322B. The coil outer resin 336B is in contact with the inner surface of the peripheral wall of the upper case 326B and the inner wall of the lower case 327B. The coil outside resin 336B is integrally molded with the stator 223B after the stator 223B is assembled and before the rotor 24 is assembled when the motor unit 316B is assembled. The coil outside resin 336B is used for all the electric materials in the stator 323B (electrically exposed ones, here, each coil 45, the wire portion wound around the guide wall 90, the crossovers 117A to 117C and the sensor circuit board 47, and Cover the fusing terminal 99 and the weld 101).
Further, the high thermal conductor 338 described above is arranged in a portion of the motor case 322B between the upper case 326B and the lower case 327B and on the radially outer side of the stator core 40.
Further, a ventilation port 339a is opened on the upper wall of the upper case 326B, and a ventilation port 339b is opened on the lower wall of the lower case 327B. The wind generated by the centrifugal fan 35 enters the motor case 322B from the ventilation port 339a, passes through the upper gap, the coil outer resin 336B and the rotor 24, and the lower gap, and then from the ventilation port 339b. It is discharged to the outside of the motor case 322B.

A lawn mower according to a 3-2nd mode is held in a motor case 322B, has a stator core 40, a coil 45, and a stator 323B having an insulating portion 44 interposed between the stator core 40 and the coil 45, and the inside of the stator 323B. And a spindle 17 that is driven by the rotation shaft 25. The stator 323B is provided outside the coil 45, and the stator core 40 and the motor case 322B. Has a coil outer side resin 336B which is a resin contacting the upper and lower inner surfaces (from the peripheral surface of the upper case 326B to the peripheral surface of the lower case 327B). Therefore, the brushless motor 321B is efficiently dissipated by the coil outer resin 336B that is in contact with the stator core 40 and the motor case 322B, and a lawnmower including the brushless motor 321B having excellent heat dissipation is provided. Furthermore, since all the electric materials in the stator 323B are covered with the coil outer resin 336B, the brushless motor 321B has waterproofness and dustproofness.
Furthermore, the motor case 322B has ventilation ports 339a and 339b. Therefore, the coil 45, the stator core 40, and the like are cooled from the inside as well, and the heat dissipation is further improved.

[Modification of Third Embodiment]
In addition, the said 3rd form has the modification similar to a 1st form and a 2nd form suitably.
Further, the coil outer side resins 336A and 336B may be provided for each coil 45 as in the case of the 2-1 and 2-3 forms, and in this case, there is a gap between the coil outer side resins 336A and 336B. This makes it easier for the wind to pass through in the motor case 322B, increasing the surface area of the coil outer side resins 336A, 336B and increasing the portion of the coil outer side resins 336A, 336B in contact with the wind.
Furthermore, the coil outer side resin 336B may have fins 237 projecting into the gap with the motor case 322B, as in the second, second and third forms.
The high thermal conductor 338 may be omitted.

[Fourth form]
The fourth mode of the present invention is the same as the first mode except for the side view of the fins of the motor case. The fourth mode includes the 4-1th mode to the 4-4th mode depending on the side view of the fin. Members and portions similar to those in the first embodiment are designated by the same reference numerals, and description thereof will be appropriately omitted.

[Form 4-1]
FIG. 23(B) is an explanatory view (partially developed view) of the side view shape of the fin 465A in the motor case 422A of the lawn mower according to Embodiment 4-1 of the present invention.
Like each fin 65 of the first embodiment (see FIG. 23A), each fin 465A of the 4-1st embodiment stands up from the outer peripheral surface of the motor case 422A and has a tapered shape that spreads downward in a side view. It has become. The fins 465A have a length in the up-down direction of about half that of the fins 65 and are alternately arranged in the up-down direction.
The fins 465A increase the surface area of the motor case 422A, and the wind passing between the fins 465A arranged in the circumferential direction on the upper side of the motor case 422A is circumferentially arranged on the lower side of the motor case 422A. Efficient heat dissipation is realized by hitting the fins 465A arranged in line.

[Form 4-2]
FIG. 23C is an explanatory view (partially developed view) of the side view shape of the fin 465B in the motor case 422B of the lawnmower according to the 4-2nd embodiment of the present invention.
Each fin 465B of the 4-2nd form stands up from the outer peripheral surface of the motor case 422B, and has a linear shape with a constant width over the entire side view.
The fins 465B increase the surface area of the motor case 422B and allow air to pass therethrough, thereby achieving efficient heat dissipation.

[Form 4-3]
FIG. 23D is an explanatory view (partially developed view) of the side view shape of the fin 465C in the motor case 422C of the lawnmower according to the fourth to third aspects of the present invention.
Each of the fins 465C according to the fourth to third forms is erected from the outer peripheral surface of the motor case 422C, and has a linear shape with a constant width over the entire side view. The fins 465C have a vertical length of about half that of the fins 465B, and the fins 465C are alternately arranged vertically.
The fins 465C increase the surface area of the motor case 422C, and the wind passing between the fins 465C arranged in the circumferential direction on the upper side of the motor case 422C is circumferentially arranged on the lower side of the motor case 422A. Efficient heat dissipation is realized by hitting the fins 465A arranged in line.

[Form 4-4]
FIG. 23(E) is an explanatory view (partially developed view) of the side view shape of the fin 465D in the motor case 422D of the lawnmower according to the fourth to fourth aspects of the present invention.
Each of the fins 465D of the fourth to fourth forms is erected from the outer peripheral surface of the motor case 422D, has a constant width over the entire side view, and is viewed from the side in the direction of the rotary shaft 25 (vertical direction). It is a straight line that slopes upward to the right so that it has an angle.
The upper right end of each fin 465D in a side view is on the left side of the lower left end of the right adjacent fin 465D, and the adjacent fins 465D do not overlap each other in the vertical direction. Therefore, the motor case 422D with the fins 465D can be formed by die casting.
The fins 465D increase the surface area of the motor case 422D, and the fins 465D can catch the wind W from above at an angle, and the wind W efficiently hits the fins 465D. Efficient heat dissipation is realized.

[Modification of Fourth Embodiment]
In addition, the above-described fourth mode appropriately has the same modification examples as the first to third modes.
Further, the fourth mode may be combined with the second mode or the third mode.
Further, fins having a constant width and tapered fins may be used together, or the fins may be arranged in three or more rows in the vertical direction.
The lengths of the fins may be different from each other, and the total number of times the wind hits the fins may be increased to improve the heat dissipation efficiency.
The fins 465D in the fourth to fourth aspects may be formed so as to partially overlap each other in the vertical direction by a three-dimensional printer or the like.

[Fifth form]
The fifth mode of the present invention is the same as the first mode except for the top view of the fins of the motor case. Such a fifth form includes a 5-1st form to a 5-9th form, depending on the form of the fin viewed from above. Members and portions similar to those in the first embodiment are designated by the same reference numerals, and description thereof will be appropriately omitted.

[Form 5-1]
FIG. 24(B) is an explanatory view of the top view shape of the fin 565A in the motor case 522A of the lawn mower according to Embodiment 5-1 of the present invention.
As shown in FIG. 24(A), the fins 65 radially extending in the radial direction of the first embodiment stand up from the outer edge upward on the upper surface (thrust surface) of the motor case 22. Each fin 565A of the 5-1st form in FIG. 24B stands up in a state of extending from the center of the upper surface of the motor case 522A to the peripheral edge. The upper surface of the motor case 522A of the 5-1st form is formed flat.
Such fins 565A increase the surface area of the motor case 522A and allow air to pass around the fins 565A on the upper surface of the motor case 522A, thereby achieving efficient heat dissipation.

[Form 5-2]
FIG. 24C is an explanatory diagram of the top view shape of the fin group 565B in the motor case 522B of the lawn mower according to Embodiment 5-2 of the present invention.
The fin group 565B according to the 5-2nd embodiment has a plurality of fins 565B1 standing upright in a state extending from the center of the upper surface of the motor case 522B to the peripheral edge, and a state in which the fin group 565B extends from the central portion to the peripheral edge between them. A plurality of fins 565B2 standing upright, and a plurality of fins 565B3 standing between the fins 565B1 and 565B2 and extending radially in the outer edge of the upper surface of the motor case 522B and standing upright. The upper surface of the motor case 522B in the 5-2nd form is formed flat.
With such a fin group 565B, the surface area of the motor case 522B is increased, and the total number of times that the fin group 565B on the upper surface of the motor case 522B is blown is increased, so that efficient heat dissipation is realized.

[Form 5-3]
FIG. 24D is an explanatory diagram of a top view shape of the fin group 565C in the motor case 522C of the lawn mower according to the fifth to third aspects of the present invention.
The fin group 565C of the fifth to third forms is a state in which a plurality of fins 565C1 are erected upward in a state of extending from the central portion of the upper surface of the motor case 522C to the peripheral edge and a state of extending from the central portion to the peripheral edge between them. And a plurality of fins 565C3 standing between the fins 565C1 and 565C2 and extending radially in the outer edge of the upper surface of the motor case 522C and standing above the fins 565C3. An upper bearing holding portion 66 that protrudes upward or is flat is arranged inside the fins 565C1 in the radial direction.
Such a fin group 565C increases the surface area of the motor case 522C, and increases the total number of times that the fin group 565C on the upper surface of the motor case 522C is blown by air, thereby realizing efficient heat dissipation.

[Form 5-4]
FIG. 25(A) is an explanatory diagram of a top view shape of the fin group 565D in the motor case 522D of the lawn mower according to Embodiment 5-4 of the present invention.
The fin group 565D according to the fifth to third aspects includes a fin 565D1 that is erected upward in a cylindrical shape in the center portion, a fin 565D2 that is concentrically protruded in a cylindrical shape on the outer side in the radial direction, and so on. Inside the fin 565D1, an upper bearing holding portion 66 that protrudes upward or is flat is arranged.
Due to the fin group 565D, the surface area of the motor case 522D is increased, and the fin group 565D on the upper surface of the motor case 522D is exposed to the wind to realize efficient heat dissipation.

[Form 5-5]
FIG. 25B is an explanatory diagram of a top view shape of the fin group 565E in the motor case 522E of the lawn mower according to the fifth to fifth aspects of the present invention.
The fin group 565E of the fifth to fifth forms includes a set of fins 565E1 that is erected upward in a state where a cylinder is divided in the circumferential direction in the central portion, and a set of fins that also concentrically protrude on the radially outer side. It has fins 565E2,.... Inside the fin 565E1, an upper bearing holding portion 66 that projects upward or is flat is arranged.
Due to the fin group 565E, the surface area of the motor case 522E is increased, and the total number of times that the fin group 565E on the upper surface of the motor case 522E is hit by the wind is increased, and efficient heat dissipation is realized.

[Form 5-6]
FIG. 25C is an explanatory diagram of the top view shape of the fin 565F in the motor case 522F of the lawn mower according to the fifth to sixth aspects of the present invention.
The fin 565F of the fifth-third form has a spiral shape in which the fin gradually approaches the outer edge from the center in a top view. Inside the fin 565F, an upper bearing holding portion 66 that projects upward or is flat is arranged.
The fins 565F increase the surface area of the motor case 522F, and at the same time, the fins 565F on the upper surface of the motor case 522F are blown by the wind to realize efficient heat dissipation.

[Form 5-7]
FIG. 25D is an explanatory diagram of a top view shape of the fin group 565G in the motor case 522G of the lawn mower according to the fifth to seventh aspects of the present invention.
The fin group 565G of the fifth-third aspect includes fins 565G1, 565G2... Arranged on a spiral imaginary line that gradually approaches the outer edge from the center in a top view. Inside the fins 565G1, 565G2,... On the center side, an upper bearing holding portion 66 that is protruded upward or flat is arranged.
Such a fin group 565G increases the surface area of the motor case 522G, and increases the total number of times that the fin group 565G on the upper surface of the motor case 522G is blown with air, thereby realizing efficient heat dissipation.

[Form 5-8]
FIG. 25(E) is an explanatory diagram of the top view shape of the fin 565H in the motor case 522H of the lawnmower according to the fifth to eighth aspects of the present invention.
Each of the fins 565H in the fifth to eighth modes extends in an arc shape from the center to the outer edge in a top view, and is arranged in a windmill shape as a whole. The upper surface of the motor case 522H of the fifth to eighth modes is formed flat.
The fins 565H increase the surface area of the motor case 522H, and at the same time, the fins 565H on the upper surface of the motor case 522H are exposed to the wind to realize efficient heat dissipation.

[Form 5-9]
FIG. 25F is an explanatory diagram of the top view shape of the fin 565I in the motor case 522I of the lawnmower according to the fifth to ninth aspects of the present invention.
Each of the fins 565I of the fifth to eighth modes extends in an arc shape from the central portion to the outer edge in a top view, and is arranged in a windmill shape in which the centers are not connected as a whole. An upper bearing holding portion 66 that protrudes upward or is flat is arranged radially inward of each fin 565I.
Such fins 565I increase the surface area of the motor case 522I, and the fins 565I on the upper surface of the motor case 522I are exposed to the wind to realize efficient heat dissipation.

[Modification Example of Fifth Embodiment]
In addition, the said 5th form has the example of a change similar to the 1st form thru|or the 4th form suitably.
The fifth form may be combined with the second to fourth forms.
Further, the fins (groups) 565A to 565I on the thrust surface may be formed in a tapered shape that becomes thicker toward the outer edge.
At least one of the number of installed fins (groups) 565A to 565I, the arrangement, and the size thereof can be appropriately changed.
The center side of the fin group 565D in the 5-4th form is arranged radially inward of the fin group 565C in the 5-3th form, or only the outer peripheral side of the fin group 565D in the 5-4th form is arranged in the 5-5th form. Various forms may be combined, such as being divided like forms.
Fins (groups) 565A to 565I may be provided on the lower surface instead of or together with the upper surfaces of the motor cases 522A to 522I.
As the fin 65 of the first mode is a series having the side view shape of FIG. 23(A) and the top view shape of FIG. 24(A), any one of the side view shapes of the fourth mode A series of fins having any of the top view shapes of the fifth aspect may be provided.

[Sixth form]
The sixth form of the present invention is the same as the first form except for the forms of the motor case and the stator. Members and portions similar to those in the first embodiment are designated by the same reference numerals, and description thereof will be appropriately omitted.
FIG. 26 is a vertical cross-sectional explanatory view of the motor unit 616 of the lawnmower according to the sixth embodiment of the present invention.
The motor case 622 of the motor unit 616 has a cup-like shape having a bottom on the upper side and an upper case 626 having a flange 626a on the outer side of the upper end, and a bottomed double-cylinder shape having an outer cylinder 627a. And a lower case 627 having an inner flange 627b protruding radially inward in the upper opening.
The upper case 626 and the lower case 627 are fitted on the upper side of the inner flange 627b with the flange 626a mounted thereon via an O-ring 628a (elastic member) made of an elastic body (rubber) as a waterproof member. The upper case 626 enters the outer cylindrical portion 627a of the lower case 627 and faces the inner cylindrical portion 627c of the lower case 627.
The stator core 40 of the stator 623 including the stator core 40, the upper insulator 42, the lower insulator 43, the insulating portion 44, and the coil 45 is sandwiched between the lower portion of the upper case 626 and the upper portion of the inner cylindrical portion 627c of the lower case 627. .. The stator 623 does not include the coil outer resin 36.

A bearing 68 of the rotary shaft 25 of the rotor 24 is held in the center of the upper wall of the upper case 626 via an O-ring 628b, and is rotated in the center of the lower wall of the lower case 627 via an O-ring 628c. The bearing 76 of the shaft 25 is held.
A centrifugal fan 635 is fixed to a portion of the rotary shaft 25 between the bearing 76 and the rotor core 55. The centrifugal fan 635 is arranged inside the inner cylindrical portion 627c of the lower case 627, and is arranged below the coil 45 and the stator core 40.
A through hole 627d is formed in a portion of the inner cylindrical portion 627c that is radially outward of the centrifugal fan 635, as a plurality of ventilation holes that connect the inner side and the outer side of the inner cylindrical portion 627c. On the other hand, through holes 626b serving as a plurality of ventilation holes are similarly formed in a portion of the upper case 626 below the flange 626a. Then, by these through holes 627d, 626b, and between the inner cylinder portion 627c and the outer cylinder portion 627a, between the stator core 40 and the outer cylinder portion 627a, and between the upper case 626 and the outer cylinder portion 627a, The air passage W1 is formed. The inner tubular portion 627c and the upper case 626 serve as an inner wall of the motor case 622, and the outer tubular portion 627a serves as an outer wall of the motor case 622.

When the rotary shaft 25 of the rotor 24 rotates, the centrifugal fan 635 rotates and pushes air radially outward. Then, the wind W2 passing through the through hole 627d is generated, becomes the wind W3 guided by the air passage W1 and passes through the wind passage W1, and becomes the wind W4 further passing through the through hole 626b. The wind W4 enters between the upper part of each coil 45 and the upper inner wall of the upper case 626, is sucked by the centrifugal fan 635, and becomes the wind W5 between the coils 45 (see FIGS. 6 and 7). The coils 45 and the like are cooled. During the rotation of the centrifugal fan 635, a series of winds W2 to W5 continue to circulate.

Such a sixth type lawnmower is held in the motor case 622 and has a stator core 40, a coil 45, a stator 623 having an insulating portion 44 interposed between the stator core 40 and the coil 45, and the inside of the stator 623. Is provided with a rotor 24 having a rotating shaft 25, a brushless motor 621, a spindle 17 driven by the rotating shaft 25, and a centrifugal fan 635 driven by the rotating shaft 25. It has an outer wall (the outer cylinder portion 627a of the lower case 627) and an inner wall (the inner cylinder portion 627c of the lower case 627 and the upper case 626), and holds the brushless motor 621 and the centrifugal fan 635 inside the inner wall. The wind W3 from the centrifugal fan 635 passes between the outer wall and the inner wall of the motor case 622. Therefore, the winds W2 to W5 circulate in the motor case 622, the brushless motor 621 is efficiently radiated by the winds W2 to W5, and the lawn mower provided with the brushless motor 21 having excellent heat dissipation is provided.
The motor case 622 has through holes 627d and 626b. Therefore, the air passage related to the air passage between the outer wall and the inner wall is simply formed.

[Modification Example of Sixth Mode]
In addition, the above-mentioned 6th form has the modification similar to the 1st form thru|or the 5th form suitably.
The sixth form may be combined with the first to fifth forms, and in particular, the coil outside resin of the first to third forms may be provided, or the fourth to fifth forms may be provided. Fins may be provided.
Instead of the centrifugal fan 635, another type of fan such as an axial flow fan may be used.

[Seventh form]
A seventh mode of the present invention is a grinder 701 equipped with a brushless motor 721 that is similar to the brushless motor 321B of the third to second modes except for the installation mode and the arrangement of the resin outside the coil. Members and portions similar to those in the 3-2nd embodiment are denoted by the same reference numerals, and description thereof will be appropriately omitted.

FIG. 27A is a partial central longitudinal cross sectional view of the grinder 701. FIG. 27(B) is a sectional view taken along the line AA of FIG. 27(A).
The grinder 701 includes a brushless motor 721, a resin-made tubular motor housing 722 that holds the brushless motor 721, a battery mounting portion 712 that is provided at a rear end portion of the brushless motor 721, and is capable of mounting a battery pack 713 as a power source, and a brushless motor 721. A switch (not shown) for switching on and off, a gear housing 710 connected to the front end portion of the motor housing 722, and a gear portion 716 arranged in the gear housing 710.
The rotary shaft 25 of the rotor 24 of the brushless motor 721 projects forward, drives the gear part 716, and drives the spindle 717, which is connected to the gear part 716 and extends in the vertical direction. The lower end of the spindle 717 extends downward from the lower part of the gear housing 710.
The brushless motor 721 is not placed in the motor case 22 including the upper case 26 and the lower case 27, and the outer surface of the stator core 40 of the stator 723 is in contact with the inner surface of the motor housing 722.

The coil outside resin 736 has a tubular shape, and is a portion radially outside of the tip end portion of each tooth 41 and located between the coils 45, and beyond the front and rear ends of the stator core 40 of the motor housing 722. It has a portion that contacts the inner surface. The motor housing 722 is a “case” in the present invention because the coil outer resin 736 is in contact therewith.
The front end of the coil outer side resin 736 is located on the rear side of the gear part 716, and the rear end of the coil outer side resin 736 is connected to the battery mounting part 712, and the electric component (which is disposed on the front side of the battery mounting part 712). (Not shown) is located on the front side.

The grinder 701 is held by a motor housing 722 (case) and has a stator 723 having a stator core 40, a coil 45, and an insulating portion 44 (not shown in FIG. 27) interposed between the stator core 40 and the coil 45, and a stator 723. And a spindle 717 driven by the rotating shaft 25. The stator 723 is provided outside the coils 45 and the stator core 40 and the motor. It has a coil outside resin 736 which is a resin that contacts the housing 722. Therefore, the brushless motor 721 is efficiently radiated by the coil outside resin 736, the stator core 40 and the motor housing 722, and the grinder 701 including the brushless motor 721 having excellent heat radiation is provided.

[Modification Example of Seventh Mode]
The seventh mode has modifications similar to the first to sixth modes as appropriate.
The seventh mode may be combined with the first mode to the sixth mode, in particular, the coil outside resin of the first mode or the second mode may be provided, or the resin of the fourth mode to the fifth mode may be provided. Fins may be provided.

[Eighth mode]
The eighth form of the present invention is an impact driver 801 as an example of an impact tool in which a brushless motor 821 similar to the brushless motor 321B of the third to third forms is mounted except for the installation mode and the arrangement of the resin outside the coil. .. Members and portions similar to those in the 3-2nd embodiment are denoted by the same reference numerals, and description thereof will be appropriately omitted.

FIG. 28(A) is a partial central longitudinal cross sectional view of the grinder 801. FIG. 28(B) is a sectional view taken along line BB of FIG. 28(A).
The impact driver 801 is provided on the brushless motor 821, a resin left and right half-divided motor housing 822 for supporting the left and right side portions thereof, and a lower end portion of a grip portion extending downward from the brushless motor 821 support portion. A battery mounting portion 812 to which the battery pack 813 as a cage power source can be mounted, a switch (not shown) for switching the brushless motor 821 on and off, and a gear portion 816 arranged in the motor housing 822 in front of the brushless motor 821. And have.
The motor housing 822 includes a left motor housing 822L and a right motor housing 822R, which are connected by a plurality of screws 832.
The rotary shaft 25 of the rotor 24 of the brushless motor 821 projects forward, drives the gear portion 816, and drives a spindle 817 that is connected to the gear portion 816 and extends in the front-rear direction. The front end of the spindle 817 projects forward from the upper front part of the motor housing 822.
The brushless motor 821 is not placed in the motor case 22 including the upper case 26 and the lower case 27, and the outer surfaces of the left and right side portions of the stator core 40 of the stator 823 are in contact with the left and right inner surfaces of the upper rear portion of the motor housing 822. ..

The coil outside resin 836 has a tubular shape and extends beyond the tip end portion of each tooth 41 in the radial direction and between the coils 45 and the front and rear ends of the left and right side portions of the stator core 40. It has a portion that wraps around and contacts the inner surface of the motor housing 822. The motor housing 822 is a “case” in the present invention because the coil outside resin 836 is in contact therewith.
The front end of the coil outer resin 836 is located on the rear side of the gear portion 816, and the rear end of the coil outer resin 836 is located on the rear upper end of the motor housing 822.

The impact driver 801 is held by supporting the left and right side portions with respect to the motor housing 822 (case), and the stator core 40, the coil 45, and the insulating portion 44 (not shown in FIG. 28) interposed between the stator core 40 and the coil 45. ), a brushless motor 821 arranged inside the stator 823 and provided with the rotor 24 having the rotating shaft 25, and a spindle 817 driven by the rotating shaft 25. It has a coil outside resin 836 which is a resin that contacts the outside of each coil 45 and the left and right inner surfaces of the stator core 40 and the motor housing 822. Therefore, the brushless motor 821 is efficiently radiated by the coil outside resin 836, the stator core 40, and the motor housing 822, and the impact driver 801 including the brushless motor 821 having excellent heat radiation is provided.

[Modification Example of Eighth Mode]
Note that the eighth form has modifications appropriately similar to the first to seventh forms.
The eighth form may be combined with the first form to the sixth form, and in particular, the coil outside resin of the first form or the second form may be provided, or the fourth form to the fifth form. Fins may be provided.

1... Lawn mowers (horticultural tools, electric working machines), 10... Main body housing (outer housing), 17,717,817... Spindle (output unit) 21,221A, 221B, 221C, 321A, 321B, 621 , 721, 821.. Brushless motors, 22, 322A, 322B, 522A, 522B, 522C, 522D, 522E, 522F, 522G, 522H, 522I, 622.. Motor cases (cases), 23, 223A, 223B, 223C, 323A, 323B, 623, 723, 823.. Stator, 24.. Rotor, 25.. Rotating shaft, 36, 236A, 236B, 236C, 336A, 336B, 736, 836.. Coil outside resin, 40.. Stator core, 44.. Insulation part (insulator), 45.. coil, 237.. fin (of resin outside coil), 338.. high thermal conductor, 339a, 339b.. ventilation port, 627a.. outer cylinder part (outer wall), 627c ··· Inner tube portion (inner wall), 626b, 627d ··· Through hole (vent), 635 · · Centrifugal fan (fan), 722, 822 · · Motor housing (case), 701 · · Grinder, 801 · · Impact driver (impact tool), W1...wind passage, W2-W5...wind.

Claims (21)

1. A stator having a stator core, a coil, and an insulator interposed between the stator core and the coil, the brushless motor being disposed inside the stator and having a rotor having a rotating shaft;
   An output unit driven by the rotating shaft,
   Is equipped with
   The electric working machine is characterized in that the stator has a coil outside resin which is a resin that contacts the outside of the coil and at least one of the case and the stator core.
2. The coil is provided in plural,
   The electric working machine according to claim 1, wherein the coil outside resin is arranged in series so as to commonly contact the outside of each of the plurality of coils.
3. The coil is provided in plural,
   The electric coil machine according to claim 1 or 2, wherein the resin on the outside of the coil has a groove formed between each of the coils.
4. The electric working machine according to any one of claims 1 to 3, wherein the case is made of a nonmagnetic metal.
5. The electric working machine according to any one of claims 1 to 4, wherein the resin on the outside of the coil has fins.
6. The electric working machine according to any one of claims 1 to 4, wherein the resin on the outside of the coil covers all exposed electric materials in the stator.
7. The electric working machine according to claim 6, wherein the case has a ventilation port.
8. The electric working machine according to any one of claims 1 to 7, wherein the resin outside the coil is a silicone resin.
9. The stator core has a plurality of teeth each protruding inward,
   The coil is provided in plural, and is wound around each of the teeth via the insulator,
   9. The electric working machine according to claim 1, wherein the resin on the outside of the coil does not cover the protruding end portion of each tooth.
10. The electric working machine according to any one of claims 1 to 9, wherein the case has a case fin.
11. The electric working machine according to claim 10, wherein the case fin is provided on an outer peripheral surface of the case.
12. The electric working machine according to claim 11, wherein the case fin has a tapered shape.
13. The electric work machine according to claim 11 or 12, wherein a plurality of the case fins are provided and are arranged alternately.
14. The electric working machine according to any one of claims 11 to 13, wherein the case fin is slanted with respect to a rotation shaft of the brushless motor.
15. The electric working machine according to claim 10, wherein the case fin is provided on a thrust surface of the case.
16. The electric work machine according to claim 15, wherein the case fins extend radially.
17. The electric work machine according to claim 15, wherein a plurality of the case fins are provided and concentrically project in a cylindrical shape.
18. The electric working machine according to claim 15, wherein the case fin extends in a spiral shape that gradually approaches the outer edge from the center portion.
19. The electric work machine according to claim 17 or 18, wherein the case fin is divided in a circumferential direction.
20. A stator having a stator core, a coil, and an insulator interposed between the stator core and the coil, the brushless motor being disposed inside the stator and having a rotor having a rotating shaft;
    An output unit driven by the rotating shaft,
    A fan driven by the rotating shaft,
    Is equipped with
    The case has an outer wall and an inner wall, holds the brushless motor and the fan in the inner wall,
    The electric working machine wherein the wind from the fan passes between the outer wall and the inner wall.
21. The electric working machine according to claim 20, wherein the case has a ventilation port.

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