JP2020022394A - Electrically-driven working machine - Google Patents

Abstract

To provide an electrically-driven working machine which stops the rotation of a stator with high accuracy and high strength.SOLUTION: In a lawn mower including a brushless motor 21, a spindle driven by the brushless motor 21 and a cutting blade, a stator core 40 of the brushless motor 21 is formed with a through hole 49 for stopping the rotation of a stator 23 through a screw 81.SELECTED DRAWING: Figure 4

Description

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

  2. Description of the Related Art In an electric power tool such as an electric power tool, a compact and highly durable brushless motor is often used as a power source. As this brushless motor, for example, as disclosed in Patent Document 1, an inner rotor type including a cylindrical stator and a rotor arranged inside the stator is well known, and the stator is provided on a side surface of an insulator. By engaging the projection provided on the inner surface of the housing with the locking recess, the housing is held in the housing in a detented state.

JP 2017-7068 A

  If an insulator is used to prevent the rotation of the stator, the positioning accuracy is deteriorated due to the influence of tolerance. Further, since the strength of the detent depends on the strength of the resin of the insulator, it is difficult to obtain high strength.

  Then, an object of the present invention is to provide an electric working machine which can perform rotation prevention of a stator with high accuracy and high strength.

In order to achieve the above object, the invention according to claim 1 includes a brushless motor and an output unit driven by the brushless motor, wherein the brushless motor includes a stator core, and an electrical insulating member held by the stator core. A stator provided with a coil wound around the stator core via an electrical insulating member, and a rotor rotatable with respect to the stator, wherein the stator core has a through hole for stopping the stator through a screw member and / or A concave portion is formed.
In order to achieve the above object, the invention according to claim 2 includes a brushless motor and an output unit driven by the brushless motor, wherein the brushless motor includes a stator core, and an electrical insulating member held by the stator core. A stator provided with a coil wound around the stator core via an electrical insulating member, and a rotor rotatable with respect to the stator, a lid member provided at at least one end in the axial direction of the stator, and an outer periphery of the stator core Is characterized in that a detent part for fitting with the lid member is formed.
According to a third aspect of the present invention, in the configuration of the second aspect, the rotation preventing portion is a ridge formed in parallel with the axial direction of the stator core, and the ridge has a cross-sectional shape having a circumferential width. It is characterized in that it has a tapered shape that gradually narrows outward in the radial direction of the stator core.
In order to achieve the above object, the invention according to claim 4 includes a brushless motor and an output unit driven by the brushless motor, wherein the brushless motor includes a stator core, and an electrical insulating member held by the stator core. A stator provided with a coil wound around the stator core via an electrical insulating member, and a rotor rotatable with respect to the stator, wherein at least one end in the axial direction of the stator is provided with a lid member, and an outer periphery of the stator core is provided. Is characterized in that a convex portion is formed for fitting to the lid member to prevent rotation, and a through hole for passing a screw member is formed in the convex portion.
According to a fifth aspect of the present invention, in the configuration of the fourth aspect, the protrusion is a ridge formed in parallel with the axial direction of the stator core, and the cross-sectional shape of the ridge has a circumferential width of the stator core. Is characterized in that the taper shape gradually narrows toward the outside in the radial direction.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to prevent rotation of a stator using a highly accurate and strong stator core instead of an electrically insulating member. Therefore, the rotation of the stator can be stopped with high accuracy and high strength.

It is a center longitudinal section of a lawn mower. It is an enlarged view of a motor unit part. It is a perspective view of a motor unit. It is an exploded perspective view of a motor unit. It is a longitudinal section of a motor unit. It is a cross-sectional view of the upper case part of a motor unit. It is a cross-sectional view of the lower case part of a motor unit. It is explanatory drawing of the steel plate and split type | mold of a stator core. It is a perspective view of a brushless motor. It is a top view of a stator. It is a bottom view of a stator. It is a perspective view of a short-circuit member (only the 1st-3rd metal fittings are shown with a solid line). It is a perspective view of a short-circuit member (only the 1st-3rd metal fittings are shown with a solid line). It is an exploded perspective view of a short circuit member. It is explanatory drawing of the winding method of a coil. It is explanatory drawing which shows the connection state by the 1st-3rd metal fitting from the plane of a stator. It is a connection circuit diagram by the 1st-3rd metal fittings. It is explanatory drawing of the example of a change of the rotation stop of a stator.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Description of lawn mower)
FIG. 1 is a central vertical sectional view showing a rechargeable lawn mower which is an example of an electric working machine, and FIG. 2 is an enlarged view of a motor unit.
The lawn mower 1 includes a base 2 extending in the front-rear direction and having an open lower surface, a main body 3 connected to the upper center of the base 2, and a handle 4 extending obliquely rearward and upward from the base 2.
The base 2 has a pair of wheels 5 and 5 at the front and rear, respectively, and can be moved forward and backward by the handle 4. A rear cover 6 and a grass basket 7 are provided below the handle 4 at the rear of the base 2. A switch lever 8 is provided at the rear end of the handle 4, and a lock-off button 9 for locking operation of the switch lever 8 in a normal state is provided in front of the switch lever 8. When the lock-off button 9 is pressed to release the lock of the switch lever 8, the switch lever 8 can be pulled.

The main body 3 has a main body housing 10 in which a cylindrical portion 11 at the lower end that opens downward projects into the base 2. At the upper part of the main body housing 10, a battery mounting portion 12 into which a battery pack 13 serving as a power source can be inserted and mounted from the upper rear side is formed to fall forward. The battery mounting section 12 can be opened and closed by a battery cover 14.
A controller 15 having a control circuit board (not shown) is supported at the front of the main body housing 10 in an upright state, and a motor unit 16 is provided behind the controller 15 below the battery mounting portion 12. Have been. A rotating shaft 25 of a brushless motor 21 described later projects downward from the motor unit 16, and a spindle 17 is coaxially connected to a lower end thereof. The spindle 17 projects downward from the cylindrical portion 11 into the base 2, and a horizontal plate-shaped cutting blade 20 is attached to the lower end of the spindle 17 at right angles by an inner flange 18 and a bolt 19, An output section is formed.

The motor unit 16 includes a brushless motor 21 and a motor case 22 holding the brushless motor 21, as shown in FIGS. The brushless motor 21 is an inner rotor type including a cylindrical stator 23 and a rotor 24 that penetrates through the inside of the stator 23 and has a rotation shaft 25 at an axis. The motor case 22 holds the stator 23 from above and below. It comprises an upper case 26 and a lower case 27 that support the rotation shaft 25. Here, the lower case 27 of the motor case 22 is assembled to a base 28 provided above the tubular portion 11. A motor cover 29 that covers the motor unit 16 from above is provided above the base 28.
On the other hand, on the lower side of the base 28, a bearing retainer 30 that supports the spindle 17 via a bearing 31 is assembled from below by a plurality of screws 32, and the lower end of the spindle 17 that penetrates the bearing retainer 30 is It projects into the base 2 through a baffle plate 33 screwed to the lower end of the tubular portion 11. The inner flange 18 to which the cutting blade 20 is attached is provided with a tubular portion 34 into which the lower end of the spindle 17 is fitted, and a centrifugal fan 35 is provided on the outer periphery of the tubular portion 34.

(Description of stator)
As shown in FIGS. 4 to 7, the stator 23 of the brushless motor 21 has a plurality of steel plates 40a (FIG. 8) stacked in the axial direction and a plurality of (here, 12) teeth 41, 41,. The stator core 40, the upper insulator 42 and the lower insulator 43 as resin electric insulating members integrally formed on the upper and lower ends of the stator core 40, and the inner peripheral surface of the stator core 40 and the upper and lower insulators 42, 43. Each of the teeth 41 includes an insulating portion 44 made of resin that covers an outer peripheral surface of the teeth 41 except for a protruding end surface, and a coil 45 wound around each of the teeth 41 via the insulating portion 44. The upper insulator 42 is assembled with a short-circuit member 46 that is electrically connected to a wire forming the coil 45 to form a three-phase connection, and a sensor circuit board 47 that detects the rotational position of the rotor 24. The details of the upper and lower insulators 42 and 43, the short-circuit member 46, and the sensor circuit board 47 will be described later.

On the peripheral surface of the stator core 40, three ridges 48A, 48A, 48B are formed at equal intervals in the circumferential direction. Of these, the ridges 48A, 48A have a tapered cross-sectional shape in which the circumferential width becomes smaller as going outward in the radial direction of the stator core 40, and the ridge 48B is not tapered, and the circumferential width is radial. Has a rectangular cross-sectional shape that does not change. A slight R (curved surface) swelling outward in the circumferential direction is provided on the radially outer end surface of the ridge 48B. Further, a through hole 49 is formed in each of the ridges 48A and 48B.
As shown in FIG. 8, the projections 48A, 48B are formed by overlapping projections 50A, 50B formed on each steel plate 40a, and the projection 50A has a circumferential width of the diameter of the stator core 40. The projection 50B is formed in a tapered shape that becomes smaller as going outward in the direction, and the projection 50B is not a tapered shape but a square shape in which the width in the circumferential direction does not change along the radial direction, and the through-hole 51 is formed in each. I have. A slight R (curved surface) swelling outward in the circumferential direction is provided on the radially outer end edge of the projection 50B. Notches 52 are formed between the projections 50A and 50B, and positioning grooves 53 are formed between the projections 48A and 48B when the stator is manufactured. It has become.

  The reason why the protruding ridge 48A is tapered is to take into consideration interference with the mold when the upper and lower insulators 42 and 43 and the insulating portion 44 are integrally formed. That is, as shown by a two-dot chain line in FIG. 8, when the upper and lower insulators 42, 43 and the insulating portion 44 are integrally formed on the stator core 40 with the left and right split dies 54, 54, the split dies 54, 54 are tapered. By positioning the two ridges 48A, 48A on the left and right, respectively, the ridges 48A, 48A are prevented from interfering with the split dies 54, 54 operating in the left-right direction in FIG. is there. The angle θ of the taper with respect to the operation direction is 3 ° here, but may be appropriately set in the range of 1 to 10 °. In addition, since the protruding ridges 48B also have the end surfaces provided with the bulges R outward, interference with the left and right split dies 54, 54 is prevented.

On the other hand, the rotor 24 is formed by penetrating the rotation shaft 25 through the axis of a cylindrical rotor core 55 formed by laminating a plurality of steel plates in the axial direction, and the rotor core 55 and the rotation shaft 25 are integrally formed by a resin 56. ing. At the lower end of the rotating shaft 25, a chamfered portion 57 (FIG. 4) is formed.
A plurality (eight in this case) of magnet holes 58, 58... Are formed in the periphery of the rotor core 55 concentrically in the axial direction, and a plate-like permanent magnet 59 is formed in each magnet hole 58. It is buried. On the inside of the permanent magnet 59, through-holes formed in the steel plate 40a excluding the upper and lower ends are formed with spaces (thinnings) 60, 60,... To achieve the weight reduction of the rotor 24. .

(Description of motor case)
The upper case 26 and the lower case 27 of the motor case 22 have a circular cup shape attached to the upper and lower portions of the stator 23, respectively.
First, the upper case 26 is made of a non-magnetic material such as an aluminum alloy, and as shown in FIGS. They are erected at predetermined intervals. An upper bearing holding portion 66 is formed at the center of the upper surface of the upper case 26, and a bearing 68 is held via an insulating cap 67 made of resin to support the upper end of the rotating 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, three screw boss portions 71A, 71A, 71B bulging radially outward are formed at equal intervals in the circumferential direction on the circumferential surface of the upper case 26 in the vertical direction. The screw bosses 71A, 71B correspond to the protrusions 48A, 48B of the stator core 40, respectively, and the lower ends of the screw bosses 71A, 71B are tapered or square in cross section to be fitted to the protrusions 48A, 48B, respectively. It is open in shape. A slit 72 is formed upward from the lower end between the ridges 48A and 48B on the peripheral surface of the upper case 26.

Next, the lower case 27 includes a circular end face 73 having a lower bearing holding part 74 formed at the center similarly to the upper case 26, and a cylindrical part 75 rising upward from the outer periphery of the end face 73. The holding portion 74 holds a bearing 76 and supports the rotating shaft 25 passing through the lower bearing holding portion 74. On the outer periphery of the cylindrical portion 75, bosses 77, 77,... For screwing to the base 28 are formed downward at four locations at equal intervals in the circumferential direction.
In addition, the inner surface of the end portion 73 excluding the lower bearing holding portion 74 and the inner periphery of the cylindrical portion 75 and the outer periphery excluding the boss 77 include the inner surface of the end portion 73 to the inner periphery and the outer periphery of the cylindrical portion 75. A resin layer 78 that covers continuously is formed. Bosses 79A, 79B having the same shape as the corresponding screw bosses 71A, 71B of the upper case 26 are formed in the resin layer 78 at positions corresponding to the protrusions 48A, 48B of the stator core 40 in the axial direction. The upper ends of the boss portions 79A, 79B are provided with through holes which are open in a tapered cross section or a quadrangular cross section to be fitted to the ridges 48A, 48B, respectively. Further, concave grooves 80 are respectively formed continuously below the boss portions 79A and 79B.

  Thus, the motor case 22 covers the upper case 26 from above the stator 23 with the screw bosses 71A, 71B aligned with the protrusions 48A, 48B of the stator core 40, respectively, and also mounts the bearing 68 on the upper end of the rotating shaft 25 of the rotor 24. Is held by the upper bearing holding portion 66. On the other hand, the lower case 27 is placed over the ridges 48A, 48B of the stator core 40 with the boss portions 79A, 79B from below the stator 23, and the bearing 76 assembled to the lower end of the rotary shaft 25 is attached to the lower bearing holding portion 74. Hold. In this state, the screws 81 are inserted into the boss portions 79A, 79B of the lower case 27 from below, respectively, to penetrate the ridges 48A, 48B, and then screwed into the screw boss portions 71A, 71B of the upper case 26. Then, the brushless motor 21 is covered with the upper case 26 and the lower case 27 except for a part of the outer periphery of the stator core 40, and the motor unit 16 is obtained.

In this state, between the brushless motor 21 and the motor case 22, the insulating cap 67 between the upper case 26 and the rotating shaft 25, the upper insulator 42 between the upper case 26 and the stator core 40, and the cylindrical shape of the lower case 27 Insulation is achieved by the resin layer 78 between the portion 75 and the stator core 40. Further, since a vertical gap is provided 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.
When the motor unit 16 is placed on the base 28 with the rotating shaft 25 facing downward, and a screw is screwed into each boss 77 from below the base 28, the motor unit 16 is fixed to the base 28. On the lower surface of the end face portion 73 of the lower case 27, concentric arcuate ribs 73a, 73a (FIGS. 2 and 5) for fitting the cylindrical portion 11 and positioning the motor unit 16 are formed.
Here, when the motor cover 29 is put on, the motor unit 16 is covered with the central portion including the upper bearing holding portion 66 of the upper case 26 exposed, and the fins 65 of the upper case 26 are covered on the inner surface of the motor cover 29. Are in close proximity.
Therefore, the stator 23 of the brushless motor 21 includes the screw 81 penetrating the protrusions 48A, 48B, the screw bosses 71A, 71B of the upper case 26 fitted to the protrusions 48A, 48B, and the bosses 79A, 79B of the lower case 27. Thus, the motor case 22 is prevented from rotating.

(Description of upper and lower insulators)
9 and 10, the upper insulator 42 is a ring body integrally formed on the upper end face of the stator core 40, and has a terminal holding portion 85 for holding each fusing terminal 99 provided on the short-circuit member 46 on the upper surface. , 85... Are provided at equal intervals in the circumferential direction. The terminal holding portion 85 is formed by erecting an inner wall portion 86 on the inner peripheral side and an outer wall portion 87 on the outer peripheral side at an interval 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 at the center in the circumferential direction with the outer wall portion 87. Also, on the upper surface of the upper insulator 42, five stop bosses 89, 89... For assembling the short-circuit member 46 are protruded at five positions at positions corresponding to the roots of every other tooth 41.
As shown in FIG. 11, the lower insulator 43 is a ring body integrally formed on the lower end surface of the stator core 40. On the lower surface, a position slightly displaced from the root of each tooth 41 in the circumferential direction is provided along the circumferential direction. There are twelve guide walls 90, 90,.

(Description of short-circuit member and sensor circuit board)
The short-circuit member 46 is a resin ring body one size smaller than the upper insulator 42, and has, on its outer periphery, five square tubular fitting bosses 95, 95 which respectively fit into the stop bosses 89 of the upper insulator 42 from above. , And three ribs 96, 96,... Which engage with the respective grooves 53 of the stator core 40 are protruded.
In addition, the short-circuit member 46 is formed in a step-like shape in which the thickness in the axial direction gradually decreases from the upper surface as going from the outer periphery to the inner periphery. As shown in FIGS. A first metal fitting 97U having a maximum diameter located at a thick outer peripheral portion, a second metal fitting 97W having an intermediate diameter located at an intermediate portion having a thick inner wall, and a third metal member 97W having a minimum diameter located at an inner peripheral portion inside thereof. The metal fittings 97V are arranged concentrically and are insert-molded. U, W, and V attached to each bracket mean the corresponding U-phase, W-phase, and V-phase of the three-phase current.

  The first to third metal fittings 97U to 97V are C-shaped strips in plan view, and projecting pieces 98, 98 projecting outward in the radial direction are provided at four positions at both ends and point symmetrical positions of both ends. Are formed, and a fusing terminal 99 is formed at the tip of each protruding piece 98, which is once bent downward, then folded 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 in the second and third metal fittings 97W and 97V. A welding portion 101 for spot-welding the power supply wires 100W and 100V is also formed at the base of the protruding piece 98 at the side end.

The first to third metal fittings 97U to 97V are arranged inside 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 shifted by a predetermined angle in the circumferential direction. In the insert-molded state, the fusing terminals 99 are projected from the outer peripheral surface of the short-circuit member 46 in a non-contact state with each other at substantially equal intervals in the circumferential direction. In the short-circuit member 46, through holes 102, 102,... Exposing the welding portions 101 of the metal fittings 97U to 97V are formed in a part of the circumferential direction in a state where they are offset at a predetermined interval, and each welding portion is formed. Power lines 100U to 100V are spot-welded to 101. A notch 103 is formed between the welded portions 101 to draw out the power supply lines 100U to 100V to the outside, with only the lower side of the short-circuit member 46 being connected.
Supporting pieces 104, 104 provided with mounting bosses 105 for mounting the sensor circuit board 47 are protruded toward the center at point symmetrical positions on the inner circumference of the short-circuit member 46, and the supporting pieces 104, 104 are provided. On the inner periphery of the short circuit member 46, a plurality of receiving pieces 106, 106,... (FIG. 13) for supporting the outer periphery of the sensor circuit board 47 project toward the center.

  The sensor circuit board 47 has a band-like shape orbiting around the inside of the short-circuit member 46 in an arc shape, and has, at both ends in the circumferential direction, fitting holes 107 for fitting the mounting bosses 105 of the support pieces 104 and 104, respectively. 107 are formed. By fitting the mounting bosses 105 into the fitting holes 107 and supporting the outer periphery of the receiving pieces 106, 106, the sensor circuit board 47 is held on the inner peripheral side of the short-circuit member 46. On the back surface of the sensor circuit board 47, rotation detecting elements 108, 108,... (FIG. 11) such as Hall elements for detecting the magnetic field of the permanent magnet 59 provided on the rotor 24 are mounted. The signal lines 109, 109... Connected to the sensor circuit board 47 and the power supply lines 100U to 100V are drawn out from the cutouts 103 of the short-circuit member 46. This draw-out position corresponds to the slit 72 provided in the upper case 26 of the motor case 22.

  As described above, the short-circuit member 46 has the five fitting bosses 95 on the outer periphery fitted to the stop bosses 89 provided on the upper surface of the upper insulator 42, and is screwed into the stop bosses 89 with screws 91 (FIG. 10) from above. When the screws are screwed and the tips of the three ribs 96 are engaged with the grooves 53 of the stator core 40 and the respective fusing terminals 99 are held by the respective terminal holding portions 85 of the upper insulator 42, the stator 23 and the sensor circuit board 47 are joined together. Assembled to In particular, the rib 96 engages with the groove 53 at three places and bites, so that it functions as an anchor for stably supporting the short-circuit member 46. The power supply lines 100U to 100V and the signal line 109 are drawn out of the slit 72 provided in the upper case 26 through a sleeve-shaped packing 82 (FIG. 3) fitted into the slit 72.

(Description of coil forming method)
As shown in FIG. 15, the coil 45 here uses a single wire 115 from the three teeth 41 positioned at 120 ° intervals using three winding nozzles (however, when distinguishing each wire, The windings are respectively started at A to C like 115A, 115B, and 115C. The same applies to other parts hereinafter.), And the winding is sequentially wound around four teeth 41 adjacent in the circumferential direction of the stator 23 as they are. By doing so, 12 coils 45 are formed at the same time. For example, in the case of the wire 115A shown in FIG. 15, the coils 45 are sequentially formed on the adjacent teeth 41 in the clockwise direction in a state where the starting end 116A is first locked to the corresponding fusing terminal 99. The winding direction at this time is a counterclockwise direction toward the teeth 41. In addition, the crossover 117A after the formation of the coil 45 is returned to the upper insulator 42 (connection side) side and locked to the fusing terminal 99 between the teeth 41, 41.

  Then, after the fourth coil 45 is formed, as shown in FIG. 11, the coil 45 is once pulled out toward the lower insulator 43 (anti-connection side) and wound around the guide wall 90 at the root of the wound tooth 41 from outside. After that, the wire is returned to the upper insulator 42 side again, and is locked to the fusing terminal 99 to which the starting end 116B of another adjacent wire 115B is locked to be the end 118A. By doing so, the direction of the starting end 116B and the direction of the end 118A of another wire 115B can be made coincident with each other and cut at the circled portion at the same time. The same applies to the end 118B of the wire 115B and the start end 116A of the wire 115C, and the end 118C of the wire 115C and the start 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 phases are shifted by one coil 45 in the circumferential direction, and as shown in FIG. Are fused with three coils 45, 45,... Therebetween. In FIG. 16, the first metal fittings 97U are hatched, the second metal fittings 97W are shaded, and the third metal fittings 97V are stippled, so that the connecting wires 117 fused by the metal fittings 97U to 97V can be easily distinguished.
The three coils 45, 45,... Adjacent in the circumferential direction are U (WU), V (UV), and W (VW) by the first to third metal fittings 97U to 97V of each phase. As a delta connection. This is because four sets are arranged in order by the first to third metal fittings 97U to 97V. Therefore, the three-phase circuit here is formed as shown in FIG. This is equivalent to a delta connection in which four coils U1 to U4, V1 to V4, and W1 to W4 of each phase of U, V, and W are connected in parallel.

(Operation of lawn mower)
In the lawn mower 1 configured as described above, when the lock-off button 9 is pressed to release the lock of the switch lever 8 and the switch lever 8 is pulled, the main switch is turned on and the battery pack 13 An ON signal is transmitted to the fifteen control circuit boards. The microcomputer of the control circuit board 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 turns ON / OFF the switching element provided on the control circuit board according to the acquired rotation state. The rotor 24 is rotated by causing the current to flow to the coils 45 of each phase of the stator 23 in order. Therefore, if the rotation shaft 25 rotates and the cutting blade 20 is rotated together with the spindle 17, and the push operation of the base 2 is performed via the handle 4, the lawn mowing can be performed by the cutting blade 20 while traveling through the wheels 5. .

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 screws 81 penetrating the ridges 48A and 48B, so that the influence of tolerance is small and the accuracy is high. The rotation can be stopped. Also, high strength can be obtained. In particular, since the screw 81 directly penetrates through the stator core 40, bending is less likely to occur as compared with a structure in which the upper and lower cases 26 and 27 are connected with the screw 81 outside the stator core 40.
Further, since the wires 115 forming the coil 45 do not cross each other, scraping due to contact between the wires 115 is less likely to occur, and durability is improved.

(Effects of the invention relating to the stator core)
As described above, according to the lawn mower 1 of the above-described embodiment, the through-hole 49 is formed in the stator core 40 of the brushless motor 21 to prevent the stator 23 from rotating through the screw member (the screw 81). , 43, the stator 23 can be prevented from rotating using the stator core 40 having high accuracy and strength. Therefore, the rotation of the stator 23 can be stopped with high accuracy and high strength.
Here, lid members (upper case 26 and lower case 27) are provided at both ends in the axial direction of stator 23, and around the outer periphery of stator core 40, the upper case 26 and lower case 27 are fitted. Since the stoppers (protrusions 48A, 48B) are provided, the rotation of the stator 23 with respect to the motor case 22 can be stopped with high accuracy and high strength using the stator core 40 also in this case.

Further, here, on the outer periphery of the stator core 40, convex portions (protrusions 48A, 48B) are formed to fit with the lid members (the upper case 26 and the lower case 27) and to prevent the rotation. Since the through hole 49 for passing the screw 81 is formed in 48B, the rotation of the stator 23 to the motor case 22 is prevented with high precision and high strength by using the ridges 48A and 48B and the screw 81. be able to.
The cross-sectional shape of the ridges 48A, 48A is tapered so that the circumferential width gradually narrows toward the outside in the radial direction of the stator core 40. Therefore, the upper and lower insulators 42, 43 and the insulating portion 44 are integrated. Interference with the split mold 54 during molding can be prevented.

In the invention relating to the stator core, the number and shape of the ridges for stopping the rotation of the stator are not limited to the above-described embodiments, but the number of ridges can be increased or decreased, and the cross-sectional shape can be changed as appropriate. For example, the protrusions need not be provided over the entire length of the stator core in the vertical direction, and may be shorter than the total length and provided on the upper end side, the lower end side, an intermediate portion, or the like. It is also possible to prevent the rotation by providing the screw member through the stator core without providing the protrusion.
Also, not limited to the rotation stop by the ridges and through holes, for example, as shown in FIG. 18, recesses 61 are formed in the outer peripheral surface of the stator core 40 along the axial direction, and screws 81 are formed in the recesses 61. It may be fitted to prevent rotation. Also in this case, the rotation of the stator 23 can be prevented by using the stator core 40 having high accuracy and strength.
Further, the rotation can be stopped by using both the through hole and the concave portion. A bolt is also included as a screw member. The object of the rotation stop is not limited to the motor case, and if there is no motor case, the rotation stop may be performed on the motor housing or the like using the through hole or the concave portion.

On the other hand, the electric working machine fixed to the housing via the motor case has been described, but the present invention can also be applied to an electric working machine fixed to the housing directly with screws using a through hole provided in the stator core. In this case, the protrusion may be fitted to the housing.
Further, when the protrusion is fitted to the housing to prevent rotation, the brushless motor can be fixed by sandwiching the divided housing. In this case, the through holes may be omitted.
Further, in the above embodiment, the motor case is formed from the upper case and the lower case, but the upper and lower sides are merely for convenience of the positional relationship, and depending on the electric working machine, may be any of left, right, front, rear, and oblique directions. No problem.
And it may be made to be fixed to a housing side only by any one lid member, such as an upper case. In this case, since the other lid member can be omitted, the ease of assembly is improved.
In addition, a fin for heat dissipation may be provided on the stator core. In addition, by using a member having high heat conductivity as a member connected to the motor case, heat dissipation can be improved.

(Effects of the invention relating to the three-phase coil connection method)
As described above, according to the lawn mower 1 of the above-described embodiment, the three-phase coils 45 of the brushless motor 21 are delta-connected in four parallels in each phase. The diameter can be reduced, and the winding property during production can be improved. Further, since the winding nozzle can be made thinner, the dead space can be reduced, which leads to an increase in output.
In particular, here, the crossover wires 117 between the coils 45 wound around the respective teeth 41 adjacent in the circumferential direction of the stator core 40 via the upper insulator 42 are connected to a plurality of sheet metal members (first Since the delta connection is formed by short-circuiting with the first to third metal fittings 97U to 97V), the connection can be made without generating a complicated crossover or cross line. Therefore, productivity can be increased, and the risk of scraping between the wires 115 can be reduced.

  In addition, the number of the three-phase coils 45 is twelve, and the four coils 45 adjacent to each other in the circumferential direction of the stator core 40 are continuously formed by the three wires 115, respectively, and one of the wires 45 adjacent in the circumferential direction is formed. Since the start end 116 of the wire 115 and the end 118 of the other wire 115 are electrically connected to the first to third fittings 97U to 97V in the same direction with respect to the short-circuit member 46, the start 116 and the end 118 of the wire 115 Can be cut at the same time, and the productivity is further improved.

In the invention relating to the three-phase coil connection method, the winding method of the wire is not limited to the above-described embodiment, and one, two, four, or six winding nozzles may be used. A coil may be formed with a book or six wires. In the case of one winding nozzle, all 12 teeth are wound by one wire (12 × 1), and in the case of two winding nozzles, six teeth are wound by two wires. To wind each (6 × 2). In the case of four winding nozzles, three teeth are wound by four wires (3 × 4), and in the case of six winding nozzles, two teeth are six. (2 × 6).
When the number of winding nozzles is one, it takes time to wind the wire around the teeth, but the number of winding nozzles is small, so that the equipment is small and the cost of the equipment is small. As the number of winding nozzles increases, the time for winding the wire around the teeth decreases, but the equipment becomes larger and the cost of the equipment increases.
The reason why the three winding nozzles are used in the above embodiment is that the balance between the time for winding the wire and the equipment is most preferable. However, the number of winding nozzles may be one or two when the merit of the equipment is emphasized, and the number of winding nozzles may be four or six when the reduction of time is emphasized.

Further, the number of phases is not limited to four, but may be five or more.
Furthermore, the shape of the sheet metal member is not limited to the first to third metal fittings of the above-described embodiment, and may be increased in width, or may be partially overlapped in the axial direction without being arranged on concentric circles. .
In addition, common to each invention, as the electric working machine, for example, as a gardening tool, there is an electric chain saw, a hedge trimmer, a mowing machine, a blower, etc., and as an electric tool, an angle drill, grinder, hammer, hammer drill, marnoko There is a reciprocating saw.

  1. Lawn mower, 2 base, 3 body, 4 handle, 10 body housing, 15 controller, 16 motor unit, 17 spindle, 20 cutting blade, 21 ..Brushless motor, 22.motor case, 23.stator, 24.rotor, 25.rotary shaft, 26..upper case, 27..lower case, 40..stator core, 40a..steel plate, 41 ··· Teeth, 42 · · · upper insulator, 43 · · · lower insulator, 45 · · · coil, 46 · · · short-circuit member, 47 · · · sensor circuit board, 48A, 48B · · · ridges, 50A, 50B · · · projections, 54 ..Split type, 55..Rotor core, 65..Fin, 71A, 71B..Screw boss part, 79A, 79B..Boss part, 81..Screw, 85..Terminal holding part, 97U to 97V. First to third bracket 99 ... fusing terminal, 115 ... wire.

Claims (5)

Brushless motor,
An output unit driven by the brushless motor,
The brushless motor,
A stator including a stator core, an electric insulating member held by the stator core, and a coil wound around the stator core via the electric insulating member;
A rotor rotatable with respect to the stator,
The electric working machine according to claim 1, wherein the stator core has a through-hole and / or a recess for preventing the stator from rotating through a screw member. Brushless motor,
An output unit driven by the brushless motor,
The brushless motor,
A stator including a stator core, an electric insulating member held by the stator core, and a coil wound around the stator core via the electric insulating member;
A rotor rotatable with respect to the stator,
At least one end in the axial direction of the stator is provided with a lid member,
An electric working machine, wherein a detent part for fitting with the lid member is formed on an outer periphery of the stator core.   The rotation preventing portion is a ridge formed in parallel with the axial direction of the stator core, and the cross-sectional shape of the ridge gradually narrows as the circumferential width goes outward in the radial direction of the stator core. The electric working machine according to claim 2, wherein the electric working machine has a tapered shape. Brushless motor,
An output unit driven by the brushless motor,
The brushless motor,
A stator including a stator core, an electric insulating member held by the stator core, and a coil wound around the stator core via the electric insulating member;
A rotor rotatable with respect to the stator,
At least one end in the axial direction of the stator is provided with a lid member,
On the outer periphery of the stator core, a projection is formed for fitting and locking the lid member, and a through hole for passing a screw member is formed in the projection. Work machine.   The protrusion is a ridge formed in parallel with the axial direction of the stator core, and the cross-sectional shape of the ridge has a taper whose width in the circumferential direction becomes gradually narrower as going outward in the radial direction of the stator core. The electric working machine according to claim 4, wherein the electric working machine has a shape.

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