Electric working machine and method for forming winding on stator of motor for electric working machine

Abstract

The present invention provides an electric working machine having a motor in which wires are wound around each tooth of a stator in an arranged state. The lawn mower has a brushless motor (21), the brushless motor (21) having a stator (23) and a rotor (24), the stator (23) having: a stator core (40) on which teeth (41) are protruding; an upper insulator (42) covering the upper and lower end surfaces of the teeth (41) in the axial direction of the stator core (40); an oblique rib (55) formed at the center of the upper end surface of the tooth (41) on the upper insulator (42) and protruding from the end surface and inclined relative to the protruding direction of the tooth (41); and a winding (45) formed by winding wires around the teeth (41) in a manner including the oblique rib (55) and sandwiching the upper insulator (42). Accordingly, the winding can be formed with a required total number of windings without worrying about the wires crossing each other or the total number of windings being reduced.

Description

Technical Field

[0001] The present invention relates to an electric working machine such as an electric tool, a gardening tool represented by a lawn mower, an air compressor for a pneumatic tool, and a method for forming a winding on a stator in a motor for the electric working machine. Background Art

[0002] In electric working machines such as electric tools, compact and highly durable brushless motors are generally used as power sources. Such brushless motors are known to be inner rotor types having a cylindrical stator and a rotor disposed inside the stator, as disclosed in Patent Document 1. A plurality of windings are wound around teeth protruding from the stator toward the axial center through an insulator.

[0003] [Prior art literature]

[0004] [Patent Literature]

[0005] Patent Document 1: Japanese Patent Publication No. 2015-126563 Summary of the invention

[0006] The stator winding is formed by automatically winding the winding wire (wire) on each tooth using a winding machine, but at this time, the wire passing through the insulator tooth (the part covering the end face of the tooth) is received by the corners on both sides of the width direction of the tooth (the circumferential direction of the stator), so a gap is generated between the wire and the center of the tooth. As a result, it is difficult to arrange the wire of each turn (one circle) in the radial direction of the stator, and the wires cross each other or the total number of windings (total number of turns) is reduced.

[0007] Therefore, an object of the present invention is to provide an electric working machine having a motor in which wires are wound around respective teeth of a stator in an aligned state, and a method for forming a winding on a stator in the motor for the electric working machine.

[0008] In order to achieve the above-mentioned purpose, the invention recorded in technical solution 1 is an electric working machine, characterized in that it includes a motor having a stator and a rotor, the stator including a stator core, an insulator, ribs and a winding, wherein the stator core is protrudingly provided with teeth; the insulator covers at least the front and rear end surfaces of the teeth in the axial direction of the stator core; the rib is formed in the central part of the end surface of at least one side of the insulator and protrudes beyond the end surface; the winding is formed by a wire, wherein the wire is wound on the teeth in a manner including the ribs and separated by the insulator.

[0009] In order to achieve the above-mentioned purpose, the invention described in Technical Solution 2 is an electric working machine, characterized in that it includes a motor having a stator and a rotor, the stator including a stator core, an insulator, ribs and a winding, wherein the stator core is protrudingly provided with teeth; the insulator covers at least the front and rear end surfaces of the teeth in the axial direction of the stator core; the rib is formed in the central part of at least one end surface of the insulator, protrudes more than the end surface, and is inclined relative to the protruding direction of the tooth; the winding is formed by a wire, wherein the wire is wound on the teeth in a manner including the rib and separated by the insulator.

[0010] The invention described in claim 3 is characterized in that, in addition to the structure of claim 1 or 2, the ribs are provided on both end surfaces of the insulator.

[0011] In order to achieve the above-mentioned purpose, the invention recorded in technical solution 4 is an electric working machine, characterized in that it includes a motor having a stator and a rotor, the stator including a stator core, an insulator, a winding and a guide portion, wherein the stator core has teeth; the insulator covers at least the front and rear end surfaces of the teeth in the axial direction of the stator core; the winding is wound on the teeth through the insulator; the guide portion is arranged on the insulator, and is used to guide the wire to the base end side of the tooth when the wire is wound to form the winding.

[0012] In order to achieve the above-mentioned purpose, the invention described in technical solution 5 is a method for forming a winding on a stator of an electric motor for an electric working machine, characterized in that an insulator is provided on a stator core on which teeth are protruding, covering at least the front and rear end surfaces of the teeth in the axial direction of the stator core, and a rib protruding more than the end surface is provided in the central part of at least one end surface of the insulator, so that a wire is wound around the teeth in a manner including the rib and separated by the insulator to form the winding.

[0013] [Effects of the invention]

[0014] According to the present invention, the wires can be wound around the teeth of the stator in an aligned state, so that the winding can be formed with a required total number of windings without worrying about the wires crossing each other or the total number of windings being reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a central longitudinal section view of the lawn mower.

[0016] Figure 2 This is an enlarged view of the motor unit.

[0017] Figure 3 It is a three-dimensional diagram of the motor unit.

[0018] Figure 4 This is an exploded perspective view of the motor unit.

[0019] Figure 5 It is a longitudinal sectional view of the motor unit.

[0020] Figure 6 is a cross-sectional view of the upper housing portion of the motor unit.

[0021] Figure 7 is a cross-sectional view of the lower housing portion of the motor unit.

[0022] Figure 8 This is a three-dimensional diagram of a brushless motor.

[0023] Fig. 9 It is a top view of the stator.

[0024] Fig.10 This is a bottom view of the stator.

[0025] Fig.11 This is a top view of the stator core before the winding is formed.

[0026] Fig.12 It is a longitudinal sectional view of the stator core showing a state where a wire is wound around a tooth.

[0027] Fig.13 This is a bottom view of the stator core before the winding is formed.

[0028] Fig.14 It is a perspective view of the short-circuit component (only the first to third metal members are indicated by solid lines).

[0029] Fig.15 This is a diagram illustrating the winding method of the winding.

[0030] Fig.16 (A) to (C) are explanatory diagrams showing the winding direction of the wire.

[0031] Fig.17 (A) to (C) are explanatory diagrams showing the steps of winding a wire around a tooth.

[0032] Fig.18 This is an explanatory diagram showing the connection state of the first to third metal members by a top view of the stator.

[0033] Fig.19 This is a wiring circuit diagram of the first to third metal parts.

[0034] [Description of Reference Numerals]

[0035] 1: lawn mower; 2: base; 3: main body; 4: handle; 10: main body shell; 15: controller; 16: motor unit; 17: main shaft; 20: blade; 21: brushless motor; 22: motor housing; 23: stator; 24: rotor; 25: rotating shaft; 26: upper housing; 27: lower housing; 40: stator core; 41: teeth; 42: upper insulator; 43: lower insulator; 45: winding; 46: short-circuit component; 47: sensor circuit substrate; 50: terminal retaining portion; 55: guide rib; 57: rib; 60: rotor core; 72U, 72W, 72V: 1st metal part to 3rd metal part; 74: fusion terminal; 90: wire; 91: starting end; 93A, 93B: corner; 94: terminal. DETAILED DESCRIPTION

[0036] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0037] (Instructions for lawn mower)

[0038] Figure 1 is a central longitudinal sectional view showing a rechargeable lawn mower as an example of an electric working machine. Figure 2 This is an enlarged view of the motor unit.

[0039] The lawn mower 1 includes a base 2 extending in the front-rear direction and opened at the lower surface, a main body 3 connected to the central upper side of the base 2 , and a handle 4 extending obliquely rearward and upward from the base 2 .

[0040] The base 2 has a pair of wheels 5, 5 at the front and rear, respectively, and can be moved forward and backward by a handle 4. A rear cover 6 and a grass collecting bag 7 are provided at the rear of the base 2 and below the handle 4. A switch lever 8 is provided at the rear end of the handle 4, and a lock button 9 for locking the operation of the switch lever 8 under normal conditions is provided in front of the switch lever 8. When the lock button 9 is pressed to unlock the switch lever 8, the switch lever 8 can be pulled.

[0041] The main body 3 has a main body case 10 with a cylindrical portion 11 whose lower end is open downwardly protruding into the base 2. A battery mounting portion 12 is formed at the upper portion of the main body case 10 in a front-downward posture into which a battery pack 13 as a power source can be inserted from the upper rear side. The battery mounting portion 12 can be opened and closed by a battery cover 14.

[0042] In addition, at the front of the main body housing 10, a controller 15 having a control circuit substrate (not shown) is supported in a vertically erected state, and a motor unit 16 is provided behind the controller 15 and below the battery mounting portion 12. A rotating shaft 25 of a brushless motor 21 described later protrudes downward from the motor unit 16, and a main shaft 17 is coaxially connected to its lower end. The main shaft 17 protrudes downward from the cylindrical portion 11 into the base 2, and at the lower end of the main shaft 17, a horizontal plate-shaped blade 20 is orthogonally mounted by an inner flange 18 and a bolt 19 to form an output portion.

[0043] Also like Figure 3 , Figure 4 As shown, the motor unit 16 has a brushless motor 21 and a motor housing 22 that holds the brushless motor 21. The brushless motor 21 is an inner rotor type composed of a cylindrical stator 23 and a rotor 24 that penetrates the inside of the stator 23 and has a rotating shaft 25 at the axis, and the motor housing 22 is composed of an upper housing 26 and a lower housing 27 that hold the stator 23 from above and support the rotating shaft 25. Here, the lower housing 27 of the motor housing 22 is assembled to a base plate 28 provided on the upper side of the cylindrical portion 11. A motor cover 29 that covers the motor unit 16 from above is provided on the upper side of the base plate 28.

[0044] On the other hand, a bearing holder 30 for axially supporting the main shaft 17 through a bearing 31 is assembled from below by a plurality of screws 32 on the lower side of the base plate 28, and the lower end of the main shaft 17 passing through the bearing holder 30 passes through a baffle 33 fastened to the lower end of the cylindrical portion 11 by screws and protrudes into the base 2. A cylindrical portion 34 is provided on the inner flange 18 where the blade 20 is mounted, and a centrifugal fan 35 is provided on the outer periphery of the cylindrical portion 34.

[0045] (Description of stator)

[0046] like Figure 5 , Figure 6 As shown, the stator 23 of the brushless motor 21 includes: a stator core 40, which is made of a plurality of steel plates stacked in the axial direction and a plurality of (here, 12) teeth 41, 41 ... protruding inwardly; an upper insulator 42 and a lower insulator 43, which are resin-made electrical insulating components and are integrally formed with the upper and lower ends of the stator core 40; a resin-made insulating portion 44, which is integrally formed across the upper and lower insulators 42 and 43 as a part of the upper and lower insulators 42 and 43, and covers the inner peripheral surface of the stator core 40 and the outer peripheral surface except the protruding end surface of each tooth 41; and a winding 45, which is wound around each tooth 41 via the insulating portion 44. A short-circuit component 46 and a sensor circuit substrate 47 are assembled on the upper insulator 42, wherein the short-circuit component 46 is electrically connected to the wire forming the winding 45 to form a three-phase connection; and the sensor circuit substrate 47 is used to detect the rotation position of the rotor 24.

[0047] Also like Figure 7 to Figure 9 As shown, three protrusions 48A, 48A, and 48B are formed on the circumferential surface of the stator core 40 at equal intervals in the circumferential direction. The protrusions 48A and 48A have a conical cross-sectional shape whose circumferential width decreases as they approach the radial outer side of the stator core 40, and the protrusion 48B is not conical, but has a quadrilateral cross-sectional shape whose circumferential width does not change in the radial direction. The radial outer end surface of the protrusion 48B is given a roughly R (curved surface) that bulges outward in the circumferential direction. In addition, a through hole 49 is formed on each protrusion 48A and 48B, and slots 40a, 40a... are formed axially between each protrusion 48A and 48B and on the circumferential surface of the stator core 40.

[0048] And, if Figure 6 and Fig.11 As shown, the upper insulator 42 is an annular body integrally formed on the upper end surface of the stator core 40, and on the upper surface, 12 terminal holding portions 50, 50... for holding the respective fused terminals 74 provided on the short-circuit component 46 are provided at equal intervals in the axial direction. The inner wall portion 51 on the inner circumference side of the terminal holding portion 50 and the outer wall portion 52 on the outer circumference side are provided vertically at intervals roughly equivalent to the diameter of the wire rod in the radial direction, so that an engagement groove 53 for engaging the fused terminal 74 is formed at the center of the inner wall portion 51 and the outer wall portion 52 in the circumferential direction. In addition, on the upper surface of the upper insulator 42, stop bosses 54, 54... for assembling the short-circuit component 46 are protrudingly provided at the root of the tooth 41 of every other tooth 41, that is, at five locations.

[0049] Furthermore, on the insulating portion 44 of the upper insulator 42, Fig.12 As shown, in the central portion of the upper end surface overlapping with each tooth 41 in the axial direction, an inclined rib 55, 55... is integrally provided protruding from the root side to the top end side of each tooth 41, and the inclined rib 55, 55... is inclined in a manner intersecting with the center of the tooth 41 extending along the radial direction of the stator core 40.

[0050] like Fig.10 and Fig.13 As shown, the lower insulator 43 is an annular body integrally formed on the lower end surface of the stator core 40, and on the lower surface, 12 guide walls 56, 56, ... are vertically provided along the circumferential direction at positions slightly offset circumferentially from the roots of each tooth 41.

[0051] In addition, on the insulating portion 44 of the lower insulator 43, on the lower end surface overlapping with each tooth 41 in the axial direction, ribs 57, 57, ... extending in the radial direction along the center of the tooth 41 are integrally provided to protrude from the root side to the tip side of each tooth 41.

[0052] On the other hand, Figures 4 to 8As shown in FIG. 1 , the rotor 24 is formed by passing the rotating shaft 25 through the axis of a cylindrical rotor core 60 formed by stacking a plurality of steel plates in the axial direction, and the rotor core 60 and the rotating shaft 25 are integrally formed by resin 61. A chamfered portion 62 ( Figure 4 ).

[0053] In addition, a plurality of (here, 8) magnet holes 63, 63 ... are formed concentrically and axially through the peripheral edge of the rotor core 60, and a plate-shaped permanent magnet 64 is embedded in each magnet hole 63. Inside the permanent magnet 64, space portions (weight reduction) 65, 65 ... are formed by stacking through holes formed in the steel plate except at the upper and lower ends, thereby achieving lightweighting of the rotor 24.

[0054] (Description of short-circuit components and sensor circuit board)

[0055] like Figure 8 , Fig. 9 As shown, the short-circuit component 46 is a resin annular body which is one circle smaller than the upper insulator 42, and has five square cylindrical engaging bosses 70, 70... protruding from the outer periphery, which are respectively engaged with the limiting bosses 54 of the upper insulator 42 from above, and three engaging ribs 71, 71... engaged with the slots 40a of the stator core 40.

[0056] In addition, the short-circuit member 46 is formed in a stepped shape in which the thickness in the axial direction decreases stepwise from the upper surface as it moves from the outer periphery to the inner periphery, and in each thickness portion, such as Fig.14 As shown in the figure, the first metal part 72U with the largest diameter located at the thickest outer peripheral part, the second metal part 72W with the intermediate diameter located at the thicker middle part inside thereof, and the third metal part 72V with the smallest diameter located at the inner peripheral part inside thereof are respectively arranged on concentric circles and insert-molded. U, W, and V marked on each metal part represent the corresponding U phase, W phase, and V phase of the three-phase current, respectively.

[0057] The first metal member 72U to the third metal member 72V are C-shaped strips when viewed from above, and protruding pieces 73, 73 ... protruding radially outward are formed at the two ends and at the central symmetrical positions of the two ends, respectively, and a fusion terminal 74 is formed at the top of each protruding piece 73, which is temporarily bent downward, folded upward, and then bent outward. A welding portion 76 for spot welding the power line 75U is formed at the root of the protruding piece 73 at one end of the first metal member 72U, and a welding portion 76 for spot welding the power line 75W and 75V is also formed at the root of the protruding piece 73 at the end opposite to the first metal member 72U on the second metal member 72W and the third metal member 72V.

[0058] The first metal member 72U to the third metal member 72V are arranged in the short-circuit member 46 in the order of the first metal member 72U, the second metal member 72W, and the third metal member 72V from the top and are shifted in phase by a predetermined angle in the circumferential direction. In the state of insert molding, the fused terminals 74, 74 ... protrude from the outer peripheral surface of the short-circuit member 46 in a non-contact state and at substantially equal intervals in the circumferential direction. The short-circuit member 46 is provided with through holes 77, 77 ... for exposing the welding portions 76 of the metal members 72U to 72V, and the power lines 75U to 75V are spot welded to the welding portions 76. Between the welding portions 76, 76, a notch 78 for leading the power lines 75U to 75V to the outside is formed in a state where only the lower side of the short-circuit member 46 is connected.

[0059] In addition, support pieces 79, 79 having mounting bosses 80 for mounting the sensor circuit substrate 47 are provided protruding toward the center at the inner periphery and center-symmetrical positions of the short-circuit component 46, and between the support pieces 79, 79, a support piece 81 ( Fig. 9 ) is provided on the inner periphery of the short-circuit component 46 so as to protrude toward the center.

[0060] The sensor circuit substrate 47 is a strip plate shaped like a circular arc around the inner side of the short-circuit component 46, and has fitting holes 85, 85 formed at both ends in the circumferential direction for the mounting bosses 80 of the support pieces 79, 79 to fit in. The mounting bosses 80, 80 are fitted in the fitting holes 85, 85 and the outer periphery is supported by the support piece 81. Figure 8 , Fig. 9 As shown, the sensor circuit board 47 is held on the inner circumference of the short-circuit component 46. On the back of the sensor circuit board 47, rotation detection elements 86, 86 ... (such as Hall elements for detecting the magnetic field of the permanent magnet 64 provided on the rotor 24) are mounted. Fig.10 The signal lines 87, 87 ... and the power lines 75U to 75V connected to the sensor circuit substrate 47 are led outward from the notch 78 of the short-circuit component 46. The leading position coincides with the slit 107 ( Figure 3 , Figure 4 )correspond.

[0061] As described above, the five engagement bosses 70 on the outer periphery are engaged with the stopper bosses 54 provided on the upper surface of the upper insulator 42 and the screws 88 ( Fig. 9) are screwed to the limiting boss 54, and the top ends of the three engaging ribs 71 are engaged with the slots 40a of the stator core 40, and each fusion terminal 74 is held in each terminal holding portion 50 of the upper insulator 42, so that the short-circuit component 46 can be assembled to the stator 23 together with the sensor circuit substrate 47. In particular, the engaging ribs 71 engage with the slots 40a at three locations and mesh with each other, thereby acting as an anchor for stably supporting the short-circuit component 46. The power line 75U~100V and the signal line 87 are connected from the slit 107 provided in the upper shell 26 through the sleeve-shaped insert (packing) 89 ( Figure 3 ) is led outward.

[0062] (Description of the method for forming the winding)

[0063] The winding 45 herein uses three bobbin openings, from three teeth 41 located at 120° intervals, such as Fig.15 As shown, one wire 90 (however, when three wires are distinguished, they are marked with A to C as shown in 90A, 90B, and 90C. The same applies to other parts below) is used to start winding, and in this state, winding is sequentially performed on four teeth 41 adjacent in the circumferential direction of the stator 23, thereby forming 12 windings 45 at the same time. For example, Fig.15 In the wire 90A shown in the figure, the starting end 91A is initially locked to the corresponding fusion terminal 74, and then the wire 90A is rotated in the clockwise direction ( Fig.15 The windings 45 are sequentially formed on adjacent teeth 41. Fig.16 As shown in (A) to (C) in FIG. 1 , the winding direction at this time is counterclockwise toward the teeth 41. In addition, the connecting wire 92A after forming the winding 45 returns to the upper insulator 42 (connection side) side and is locked to the fusion terminal 74 between the teeth 41, 41.

[0064] At this time, in the insulating portion 44 of the upper insulator 42, as shown in FIG. Fig.17 As shown in (A) in FIG. 1 , when the wire 90 returning to the connection side contacts the corner 93A located near the front side of the insulating portion 44 on the upper side end surface of the tooth 41, it is directly wound vertically around the corner 93A, but then contacts the oblique rib 55 and attempts to be wound vertically around the oblique rib 55 this time, so that the wire 90 is wound around the insulating portion 44 while approaching the root side of the tooth 41. Accordingly, Fig.17 The first turn of wire 90a shown in (B) is wound around the root of tooth 41 at corner 93B on the opposite side of insulating portion 44. The second turn of wire 90b also contacts oblique rib 55 from corner 93A near the front side. Fig.17As shown in (C) in the figure, the wire 90a is wound in an aligned state by imitating the first turn. The same is true for the third turn and the following turns. On the other hand, in the lower insulator 43, after contacting the corner 93A on the near side, it crosses the rib 57 and contacts the corner 93B on the opposite side and is also wound in an aligned state.

[0065] In this way, when the wire 90 is wound around the insulating portion 44 with a predetermined number of turns, Fig.12 As shown, each turn of the wire 90 is supported at three points on the upper surface of the insulating portion 44, namely, the left and right corners 93A, 93B and the oblique rib 55, and is supported at three points on the lower surface of the insulating portion 44, namely, the left and right corners 93A, 93B and the rib 57. Figure 6 and Fig.10 As shown, each winding 45 includes an oblique rib 55 and a rib 57 formed by sandwiching upper and lower insulators 42 and 43 .

[0066] And, after forming the fourth winding 45, as Fig.10 As shown, it is temporarily led to the lower insulator 43 side (the reverse wiring side), and after being wound from the outside around the guide wall 56 at the root of the wound tooth 41, it returns to the upper insulator 42 side again, and is locked by the fusion terminal 74 locked by the starting end 91B of the other adjacent wire 90B to become the terminal 94A. Fig.15 As shown, the direction of the starting end 91B of the other wire 90B can be made consistent with the direction of the terminal 94A and cut at the same time in the part surrounded by the circle. This is also the case for the terminal 94B of the wire 90B and the starting end 91C of the wire 90C, and the terminal 94C of the wire 90C and the starting end 91A of the wire 90A.

[0067] The first metal member 72U to the third metal member 72V of the short-circuit member 46 are arranged in a state where the phases thereof are shifted by an amount corresponding to one winding 45 in the circumferential direction. Fig.18 As shown, the connecting wires 92 between the twelve windings 45, 45 are fused with each other via three windings 45, 45, ... Fig.18 In order to easily distinguish the connection line 92 for melting the metal members 72U to 72V, the first metal member 72U is marked with a hatching line, the second metal member 72W is marked with a grid, and the third metal member 72V is marked with a dotted line.

[0068] Thus, the three windings 45, 45, ... adjacent to each other in the circumferential direction are connected in a triangle to form U (WU), V (UV), and W (VW) through the first metal member 72U to the third metal member 72V of each phase. This is because the first metal member 72U to the third metal member 72V are sequentially arranged in parallel to form four groups. Therefore, the three-phase circuit here is as follows: Fig.19This is equivalent to a delta connection in which the four windings U1 to U4, V1 to V4, and W1 to W4 of each phase of U, V, and W are connected in parallel.

[0069] (Description of the motor housing)

[0070] The upper shell 26 and the lower shell 27 of the motor housing 22 have circular cup shapes respectively sleeved on the upper and lower parts of the stator 23 .

[0071] First, the upper shell 26 is formed of a non-magnetic body such as aluminum alloy. Figures 3 to 5 As shown, from the outer periphery of the upper surface to the side surface, the heat dissipation fins 100, 100 ... in the upper and lower directions are arranged at predetermined intervals in the circumferential direction. In addition, an upper bearing holding portion 101 is formed at the center of the upper surface of the upper housing 26, and a bearing 103 is held by an insulating cover 102 made of resin to support the upper end of the rotating shaft 25. A through hole 104 is formed in the center of the upper bearing holding portion 101 and is closed by a resin cover 105.

[0072] Furthermore, three screw bosses 106A, 106A, 106B that bulge radially outward are formed at equal intervals in the circumferential direction and in the vertical direction on the circumferential surface of the upper housing 26. The screw bosses 106A, 106B correspond to the protrusions 48A, 48B of the stator core 40, respectively, and the lower ends of the screw bosses 106A, 106B are opened to have a conical cross section or a quadrilateral cross section that fits with the protrusions 48A, 48B, respectively. A slit 107 is formed on the circumferential surface of the upper housing 26 and between the protrusions 48A, 48B from the lower end upward.

[0073] Next, the lower housing 27 is composed of a circular end face portion 108 with a lower bearing holding portion 109 formed in the center and a cylindrical portion 110 rising upward from the outer circumference of the end face portion 108, similarly to the upper housing 26. The bearing 111 is held by the lower bearing holding portion 109 and supports the rotating shaft 25 passing through the lower bearing holding portion 109. On the outer circumference of the cylindrical portion 110, bosses 112, 112, ... for screw fastening to the base plate 28 are formed downward at four locations at equal intervals in the circumferential direction.

[0074] In addition, a resin layer 113 is formed on the inner surface of the end surface 108 except the lower bearing holding portion 109, the inner periphery of the cylindrical portion 110, and the outer periphery except the boss 112, which continuously covers from the inner surface of the end surface 108 to the inner periphery and outer periphery of the cylindrical portion 110. In the resin layer 113, at positions corresponding to the protrusions 48A and 48B of the stator core 40, boss portions 114A and 114B having the same shape as the corresponding screw boss portions 106A and 106B of the upper housing 26 are formed in the axial direction. The upper ends of the boss portions 114A and 114B have through holes with conical or quadrilateral cross sections that are opened to fit with the protrusions 48A and 48B, respectively. In addition, grooves 115 are formed continuously on the lower sides of the boss portions 114A and 114B, respectively.

[0075] In this way, the upper housing 26 of the motor housing 22 is covered from above the stator 23 by aligning the screw bosses 106A and 106B with the protrusions 48A and 48B of the stator core 40, and the bearing 103 assembled to the upper end of the rotating shaft 25 of the rotor 24 is held by the upper bearing holding portion 101. On the other hand, the lower housing 27 is covered from below the stator 23 by aligning the bosses 114A and 114B with the protrusions 48A and 48B of the stator core 40, and the bearing 111 assembled to the lower end of the rotating shaft 25 is held by the lower bearing holding portion 109. In this state, the screws 116 are inserted from below into the bosses 114A and 114B of the lower housing 27 and penetrate the protrusions 48A and 48B, and then screwed into the screw bosses 106A and 106B of the upper housing 26. Then, the brushless motor 21 is covered by the upper case 26 and the lower case 27 except for a part of the outer periphery of the stator core 40 , thereby obtaining the motor unit 16 .

[0076] In this state, in the brushless motor 21, first, basic insulation is implemented by the basic insulating member (integrally formed upper and lower insulators 42, 43 and insulating portion 44) interposed between the stator core 40 as the internal metal and the winding 45 as the charging portion.

[0077] In addition, additional insulation is provided by the resin 61 between the rotating shaft 25 and the rotor core 60, the insulating cover 102 between the upper case 26 and the rotating shaft 25, and the resin layer 113 between the cylindrical portion 110 of the lower case 27 and the stator core 40, so that the stator core 40 and the rotating shaft 25 are doubly insulated. In addition, a gap in the vertical direction is provided between the upper case 26 and the lower case 27, so that the stator 23 can be assembled even if the axial dimension thereof changes.

[0078] When the motor unit 16 is placed on the base plate 28 with the rotating shaft 25 facing downward and screws are screwed into the bosses 112 from below the base plate 28, the motor unit 16 is fixed to the base plate 28. The lower surface of the end surface 108 of the lower housing 27 is formed with arc ribs 108a, 108a ( Figure 2 , Figure 5 ).

[0079] Here, when the motor cover 29 is closed, the motor unit 16 is covered with the central portion including the upper bearing holding portion 101 of the upper housing 26 exposed, so that the fins 100 , 100 . . . of the upper housing 26 are close to the inner surface of the motor cover 29 .

[0080] Therefore, stator 23 of brushless motor 21 is prevented from rotating relative to motor housing 22 by screws 116 passing through protrusions 48A, 48B, screw bosses 106A, 106B of upper housing 26 engaged with protrusions 48A, 48B, and bosses 114A, 114B of lower housing 27.

[0081] (Lawn mower action)

[0082] In the lawn mower 1 configured as described above, when the lock button 9 is pressed to unlock the switch lever 8 and the switch lever 8 is pulled, the main switch is turned on and an on signal is transmitted from the battery pack 13 to the control circuit board of the controller 15. The microcomputer of the control circuit board obtains the rotation state of the rotor 24 based on the detection signal obtained from the rotation detection element 86 of the sensor circuit board 47, and performs on / off operation on the switch element provided on the control circuit board according to the obtained rotation state, and rotates the rotor 24 by causing current to flow sequentially to the windings 45 of each phase of the stator 23. According to this, the blade 20 rotates together with the main shaft 17 due to the rotation of the rotating shaft 25, so that if the base 2 is pressed by the handle 4, the blade 20 can cut grass while the wheel 5 is running.

[0083] At this time, in the brushless motor 21, the stator 23 is stopped relative to the motor housing 22 assembled on the base plate 28 by the screws 116 penetrating the protrusions 48A and 48B, so the influence caused by the tolerance is small and the rotation can be stopped with high precision. In addition, high strength can also be obtained. In particular, since the screws 116 directly penetrate the stator core 40, it is less likely to bend compared to the structure in which the upper and lower housings 26 and 27 are connected by the screws 116 on the outside of the stator core 40.

[0084] Furthermore, the wires 90 forming the winding 45 do not cross each other, so it is difficult to cause wear due to contact between the wires 90, and the durability is also improved. In particular, each wire 90 is supported at three points on the upper and lower surfaces of the insulating portion 44 by the oblique ribs 55 and ribs 57 and the corners 93A and 93B, so it is difficult for the wire 90 to loosen or deviate.

[0085] (Effects of the invention related to the oblique ribs and ribs provided on the upper insulator)

[0086] According to the above-mentioned lawn mower 1, there is a brushless motor 21 (motor), the brushless motor 21 having a stator 23 and a rotor 24, the stator 23 including a stator core 40, upper and lower insulators 42, 43 (insulators), oblique ribs 55 (ribs), ribs 57 and windings 45, wherein the stator core 40 is provided with protruding teeth 41; the upper and lower insulators 42, 43 cover the upper and lower end surfaces of the teeth 41 in the axial direction of the stator core 40; the oblique ribs 55 are formed on the upper and lower end surfaces of the teeth 41; The central portion of the upper end surface of the tooth 41 in the insulator 42 protrudes from the end surface and is inclined relative to the protruding direction of the tooth 41; the rib 57 is formed in the central portion of the lower end surface of the tooth 41 in the lower insulator 43, and protrudes from the end surface; the winding 45 is formed by the wire 90 wound on the tooth 41 in a manner including the oblique rib 55 and the rib 57 and sandwiching the upper and lower insulators 42 and 43, thereby allowing the wire 90 to be wound in an aligned state on each tooth 41 of the stator 23. Therefore, there is no need to worry about the wires 90 crossing each other or reducing the total number of windings, and the winding 45 can be formed with a desired total number of windings.

[0087] In particular, here, the oblique ribs 55 and the ribs 57 are provided on the upper and lower end surfaces of the upper and lower insulators 42 and 43 , so that the wires 90 can be arranged more reliably.

[0088] In addition, the above-mentioned method makes the upper side oblique ribs and the lower side ribs along the protruding direction of the teeth, but the upper and lower ribs can also be opposite ribs. In addition, both upper and lower end surfaces can also be oblique ribs, or both end surfaces can be ribs in the protruding direction of the teeth.

[0089] Furthermore, it is also possible to provide oblique ribs or ribs in the protruding direction of the teeth instead of providing oblique ribs or ribs in the protruding direction of the teeth on only one end surface of the upper and lower end surfaces of the upper and lower insulators. The height and width of the ribs can also be changed appropriately. It is also possible to change the height or width in the radial direction toward the stator, or to provide a plurality of ribs on the end surface.

[0090] Furthermore, the rib is not limited to being integrally formed with the insulator, and can also be used as a guide portion for guiding the wire toward the base end side of the tooth when the wire is wound by fixing a rib-shaped separate component to the end face of the insulator. In this case, the wire can also be wound in an arranged state in the same manner as in the above-mentioned manner. The shape can be changed in the same manner as the rib.

[0091] (Effects of the invention related to the method for forming windings on a stator)

[0092] According to the formation method of forming the winding 45 on the stator 23 in the above-mentioned manner, the stator core 40 on which the teeth 41 are protruding is provided with upper and lower insulators 42 and 43 that cover the upper and lower end surfaces of the teeth 41 in the axial direction of the stator core 40, and the oblique ribs 55 and ribs 57 that protrude from the end surfaces are provided at the central parts of the upper and lower end surfaces of the upper and lower insulators 42 and 43, and the winding 45 is formed by winding the wire 90 around the teeth 41 in a manner including the oblique ribs 55 and the ribs 57 and sandwiching the upper and lower insulators 42 and 43, so that the wire 90 can be wound around each tooth 41 of the stator 23 in an aligned state. Therefore, there is no need to worry about the wires 90 crossing each other or the number of windings being reduced, and the winding 45 can be formed with a desired number of windings.

[0093] In addition, the order of winding the wires around the teeth is not limited to the above-mentioned method, and can be changed appropriately, such as winding one wire around the teeth adjacent to each other in the circumferential direction in sequence to form a winding at one time. The short-circuit component can also adopt a star connection instead of a delta connection by changing the configuration or method of the metal parts. It is also possible to make the fusion terminal independent of the metal parts and hold it on the insulator, or to omit the short-circuit component and weld the wire to a single fusion terminal to form a three-phase connection.

[0094] In addition, in each invention, in addition to lawn mowers, the electric working machine includes, for example, a compressor; the gardening tools include electric chain saws, hedge trimmers, lawn mowers, blowers, etc.; the electric tools include angle drills, grinders, electric hammers, hammer drills, circular saws, reciprocating saws, etc.

Claims

1. An electric working machine, characterized in that: comprising an electric machine having a stator and a rotor, The stator comprises a stator core, an insulator, ribs and windings, wherein: The stator core is protrudingly provided with teeth; The insulator covers at least the front and rear end surfaces of the teeth in the axial direction of the stator core; The rib is formed at a central portion of at least one of the end surfaces of the insulator and protrudes beyond the end surface; The winding is formed of a wire, wherein the wire is wound around the teeth in a manner including the rib and interposing the insulator therebetween. The rib allows the wire to be wound around the insulator while approaching the root side of the tooth.

2. An electric working machine, characterized in that: comprising an electric machine having a stator and a rotor, The stator comprises a stator core, an insulator, ribs and windings, wherein: The stator core is protrudingly provided with teeth; The insulator covers at least the front and rear end surfaces of the teeth in the axial direction of the stator core; The rib is formed at a central portion of at least one of the end surfaces of the insulator, protrudes beyond the end surface, and is inclined relative to a protruding direction of the teeth; The winding is formed of a wire, wherein the wire is wound around the teeth in a manner including the rib and interposing the insulator therebetween. The rib allows the wire to be wound around the insulator while approaching the root side of the tooth.

3. The electric working machine according to claim 1 or 2, characterized in that: The ribs are disposed on both end surfaces of the insulator.

4. An electric working machine, characterized in that: comprising an electric machine having a stator and a rotor, The stator comprises a stator core, an insulator, a winding and a guide part, wherein: The stator core has teeth; The insulator covers at least the front and rear end surfaces of the teeth in the axial direction of the stator core; The winding is wound around the teeth via the insulator; The guide portion is provided at a central portion of the end surface of the insulator, and is used to guide the wire to the base end side of the tooth when the wire forming the winding is wound.

5. A method for forming windings on a stator of a motor for an electric working machine, characterized in that: An insulator is provided on a stator core on which teeth are protruding, and covers at least the front and rear end surfaces of the teeth in the axial direction of the stator core, and a rib protruding from the end surface is provided at the center of at least one end surface of the insulator. The wire is wound around the teeth in a manner including the rib and through the insulator to form a winding, The rib allows the wire to be wound around the insulator while approaching the root side of the tooth.

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