JP2019201472A - Electric power tool - Google Patents

Abstract

To provide an electric power tool comprising a motor which can reduce the number of components or steps of assembly while achieving more compactification.SOLUTION: A driver drill includes a brushless motor formed by a stator 21 and a rotor, the stator 21 being wound with a plurality of coils 26 via a front insulator 24 and a rear insulator 25, which are positioned on front and rear sides of an axial direction. Short-circuit metal fittings 36A to 36C that short-circuit between certain crossover wires 53, 53 with fusing terminals 38A to 38C electrically connected to the crossover wire 53 of coils 26, 26 are inserted and formed in the front insulator 24.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an electric tool including a motor as a drive source.

The motor mounted in the electric tool has a different structure depending on the electric tool model (light load model, heavy load model). That is, a motor for a light load model uses a solderable wire to flow a main current to the sensor circuit board, and a motor for a heavy load model directly connects a lead wire (power line) to a fusing terminal. It has a structure.
In this case, the motor for the light load model is small and saves space, but the motor for the heavy load model is larger than that for the light load model, and thus is not suitable for making the product compact.

  In view of this, the present applicant attached a short-circuit member having three sheet metal members respectively connecting the connecting wires between the diagonally located coils to the insulator provided in the stator of the motor in Patent Document 1, and each sheet metal member Is electrically connected to the connecting wire between the coils via a fusing terminal provided in the insulator, thereby providing an invention that achieves compactness.

Japanese Patent Laying-Open No. 2015-56953

However, the short-circuit member used in the stator of Patent Document 1 is a member that is manufactured separately from the insulator by insert-molding a sheet metal member into resin, which sandwiches the sensor circuit board that detects the rotational position of the rotor. Therefore, there is a limit to downsizing the stator in the axial direction.
In addition, when manufacturing the stator, it is necessary to screw the short-circuit member to the insulator together with the sensor circuit board, solder the power wire to the coil to the sheet metal member of the short-circuit member, and the fusing terminal to the sheet metal member. Since the work of fusing is also necessary, the number of parts and the number of assembly steps are increased. This problem also applies to the connection between the metal fitting and the crossover wire when the crossover wires are not short-circuited.

  Accordingly, an object of the present invention is to provide an electric tool provided with a motor that can achieve further compactness and can reduce the number of parts and the number of assembly steps.

In order to achieve the above object, an invention according to claim 1 includes a motor including a stator and a rotor, and a plurality of coils are wound around the stator via insulators positioned in front and rear in the axial direction. An electric tool,
A short-circuit fitting that includes a connecting portion that is electrically connected to a connecting wire between coils and short-circuits predetermined connecting wires is insert-molded in an insulator.
The invention according to claim 2 is characterized in that, in the configuration of claim 1, a nut for electrically connecting a power supply line for supplying power to the coil to the short-circuit metal fitting and assembling the insulator is insert-molded into the insulator. To do.
According to a third aspect of the present invention, in the configuration of the second aspect, the connecting portion is a fusing terminal.
According to a fourth aspect of the present invention, in the configuration of the second or third aspect, the power terminal of a power terminal unit having a power terminal to which a power line is electrically connected is screwed to the nut. Features.
According to a fifth aspect of the present invention, in the configuration of the fourth aspect, a sensor circuit board for detecting the rotation of the rotor is temporarily fixed to a surface of the power terminal unit on the insulator side.
According to a sixth aspect of the present invention, in the configuration of the fifth aspect, the power supply terminal unit is ring-shaped and is in contact with the sensor circuit board over the entire circumference.
In order to achieve the above object, an invention according to claim 7 includes a motor including a stator and a rotor, and at least the first coil and the first coil are connected to the stator via insulators positioned in front and rear in the axial direction. An electric tool in which two coils are wound,
A metal fitting electrically connected to the crossover between the first coil and the second coil is insert-molded in the insulator.
According to an eighth aspect of the present invention, in the configuration of the seventh aspect, the first coil and the second coil are adjacent to each other in the circumferential direction of the stator.
According to a ninth aspect of the present invention, in the configuration of the seventh aspect, a third coil is wound between the first coil and the second coil.
In order to achieve the above object, an invention according to claim 10 includes a motor including a stator and a rotor, and at least the first coil and the first coil are connected to the stator via insulators positioned in the axial direction. An electric tool in which two coils are wound,
A nut is insert-molded in the insulator, and other members can be screwed to the insulator using the nut.

  According to the present invention, since the short-circuit fittings and fittings that short-circuit the connecting wires between the coils are insert-molded in the insulator, it is not necessary to assemble the short-circuit fittings and the like to the insulator when manufacturing the stator. This leads to a reduction in assembly man-hours. Also, compactness can be achieved.

It is a general view of a driver drill. It is a center longitudinal cross-sectional view of the rear part of a main body. It is a perspective view from the front of a brushless motor. It is a perspective view from the back of a brushless motor. It is explanatory drawing of a brushless motor, (A) shows a front surface, (B) shows a side surface, (C) shows a back surface, respectively. It is a disassembled perspective view of a stator. It is explanatory drawing of a front insulator, (A) shows a front surface, (B) shows a side surface, (C) shows a back surface, respectively. It is a perspective view which decomposes | disassembles and shows a front insulator in the resin molding part, a short circuit metal fitting, and a nut. It is explanatory drawing of the short circuit metal fitting and nut which abbreviate | omitted the resin molding part, (A) shows a front surface, (B) shows a bottom face, (C) shows a back surface, respectively. It is a perspective view of the front insulator which shows a resin molding part with an imaginary line. It is explanatory drawing of a sensor circuit board, (A) is a back surface, (B) is a side surface, (C) is a front surface, (D) shows the AA line cross section, respectively. It is explanatory drawing of a power supply terminal unit, (A) is the perspective from the front, (B) is the perspective from the back, (C) shows the front. It is a perspective view which decomposes | disassembles and shows a power terminal unit to the resin molding part, a power terminal, and a power wire. It is explanatory drawing of the front insulator using the short-circuit metal fitting of the example of a change, (A) shows a front and (B) shows a side, respectively. It is a perspective view which decomposes | disassembles and shows the front insulator using the short-circuit metal fitting of the example of a change into the resin molding part, the short-circuit metal fitting, and a nut. It is explanatory drawing of the short-circuit metal fitting and nut of the example of a change which abbreviate | omitted the resin molding part, (A) shows a front surface, (B) shows a bottom face, respectively. (A) is explanatory drawing from the stator back surface which shows the structure which short-circuits a connecting wire with the short-circuit metal fitting insert-molded to the back insulator, (B) is a connection diagram.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Overall description of driver drill)
FIG. 1 is an overall view of a driver drill as an example of an electric tool, and FIG. 2 is a central longitudinal sectional view of a rear portion of a main body. The driver drill 1 has a T-shape in which a handle 3 is formed downward on a main body 2 extending in the front-rear direction, and a battery pack 5 serving as a power source is mounted on a battery mounting portion 4 formed on the lower end of the handle 3. Has been.
The housing of the main body 2 has a front housing 7 that houses a clutch mechanism and a spindle (not shown) in front of a cylindrical main body housing 6 that houses a brushless motor 20 and a planetary gear speed reduction mechanism 94, which will be described later, from the front. The cap-shaped rear cover 9 is assembled to the rear side of the main body housing 6 with screws 10 and 10 at two places, upper and lower, from the rear side.

  A mode switching ring 11 and a clutch adjustment ring 12 are provided in front of the front housing 7, and a chuck 13 attached to the spindle is provided in front of the clutch adjustment ring 12. The handle 3 is connected to the main body housing 6, and the handle 3 and the main body housing 6 are formed by assembling the left and right half housings 6a, 6b with screws 14, 14,. A switch (not shown) is accommodated in the handle 3, and a trigger 15 provided on the switch protrudes forward. A motor forward / reverse switching button 16 is provided above the switch, and a light (not shown) for irradiating the front of the chuck 13 is provided above the trigger 15.

(Description of brushless motor)
The brushless motor 20 accommodated in the rear portion of the main body housing 6 is an inner rotor type including a stator 21 and a rotor 22. As shown in FIGS. 3 to 6, the stator 21 includes a cylindrical stator core 23 formed of a plurality of laminated steel plates, a front insulator 24 and a rear insulator 25 provided on the front and rear end surfaces of the stator core 23 in the axial direction, And six coils 26, 26... Wound around the stator core 23 via the insulators 24 and 25. In addition, a sensor circuit board 27 and a power supply terminal unit 28 described later are attached to the front insulator 24.

First, the stator core 23 includes six teeth 30, 30... Projecting toward the axial center, and six slots 31, 31... Are formed between the teeth 30, 30.
Next, the front insulator 24 is a resin molded product having a ring shape substantially the same diameter as the stator core 23, and as shown in FIG. 7, protrudes toward the axial center side toward the inner peripheral side, and continues to the front of the teeth 30 of the stator core 23. Six projecting portions 32, 32,... On the back side of the front insulator 24, six fitting portions 33, 33... That fit into the slots 31 of the stator core 23 are projected.
In addition, a positioning recess 34 is formed at the center in the left-right direction on the upper surface of the front insulator 24, and two triangular cutouts 35, 35 are formed on the left and right side surfaces. . The positioning recesses 34 and the notches 35 are configured such that the rear surfaces are closed by the stator core 23.

  Then, as shown in FIGS. 2, 7, and 8, three short-circuit fittings 36 </ b> A to 36 </ b> C and three nuts 37 </ b> A to 37 </ b> C are embedded in the front insulator 24 by insert molding. The short-circuit brackets 36A to 36C are made of sheet metal whose front view is formed in a substantially semicircular shape along the shape of the front insulator 24, and the positions of the short-circuit brackets 36A to 36C are shifted in the axial direction so as not to contact each other. 36A, the short-circuit bracket 36B, and the short-circuit bracket 36C are arranged in this order. A pair of fusing terminals 38A to 38C as connecting portions located diagonally in the diameter direction of the front insulator 24 are integrally formed at both ends in the circumferential direction of each short-circuit metal fitting 36A to 36C, respectively. Between 38 </ b> A to 38 </ b> C, receiving portions 39 </ b> A to 39 </ b> C parallel to the front surface of the stator core 23 are formed so as to protrude forward. The fusing terminals 38 </ b> A to 38 </ b> C each have an inner plate part 40 that protrudes forward while facing each other diagonally, and a bent piece 41 that is folded back and forward from the rear end of the inner plate part 40. ing. Through holes 42 are formed in the receiving portions 39A to 39C, respectively.

  As shown in FIGS. 9 and 10, the foremost short-circuit metal fitting 36 </ b> A is disposed along the circumferential direction in the upper portion of the front insulator 24, and is folded up from the lower edge to the front side at the position of the positioning recess 34. By forming the bent upper portion 43 to be bent, interference with the positioning recess 34 is avoided. In addition, at the positions of the left and right cutout portions 35, 35 on the upper side of the front insulator 24, the laterally bent portions 44, 44 that are raised to the front side in an L shape when viewed from the front are formed. Interference with 35 is avoided. The receiving portion 39A of the short-circuit fitting 36A is formed between the left side bent portion 44 and the fusing terminal 38A.

  The short-circuit fitting 36B located behind the short-circuit fitting 36A has one fusing terminal 38B positioned on the left side of the upper bent portion 43 of the short-circuit fitting 36A and inside the short-circuit fitting 36A, and the other fusing terminal 38B in front. In a state of being positioned on the lower right side of the insulator 24, it is arranged along the circumferential direction at the left side portion of the front insulator 24. In this state, the short-circuit fitting 36B overlaps a part of the upper side with the left side of the short-circuit fitting 36A in the front-rear direction, and the portion overlapping the rear of the receiving portion 39A of the short-circuit fitting 36A has a through hole of the receiving portion 39A. A through hole 45 having a diameter larger than 42 is formed. Here, the receiving portion 39B is formed at an intermediate portion in the circumferential direction of the short-circuit fitting 36B, and a relief portion 46 that avoids interference with the lower left notch portion 35 of the front insulator 24 is provided below the receiving portion 39B. Is formed.

The short-circuit fitting 36C located behind the short-circuit fitting 36B has one fusing terminal 38C positioned on the right side of the upper bent portion 43 of the short-circuit fitting 36A and inside the short-circuit fitting 36A, and the other fusing terminal 38C in front. In a state where it is positioned on the lower left side of the insulator 24, it is arranged along the circumferential direction at the right side portion of the front insulator 24. In this state, the short-circuit metal fitting 36C overlaps a part of the upper side with the right side of the short-circuit metal fitting 36A in the front-rear direction. The lower ends of the short-circuit brackets 36B and 36C intersect with each other on the lower side of the front insulator 24, and the fusing terminals 38B and 38C on the lower end side are respectively positioned on the inner side of the counterpart bracket. Here, the receiving portion 39C is formed at an intermediate portion in the circumferential direction of the short-circuit metal fitting 36C, and on the lower side of the receiving portion 39C is an escape portion 47 that avoids interference with the notch portion 35 on the lower right side of the front insulator 24. Is formed.
The nuts 37A to 37C are arranged on the back side of the receiving portions 39A to 39C in the front-rear direction in which the nuts 37A to 37C contact the rear surfaces of the receiving portions 39A to 39C coaxially with the through holes 42, respectively.

Here, in the molded portion of each of the fusing terminals 38A to 38C in the front insulator 24, a pair of holding portions 48 and 48 that hold both circumferential ends of the inner plate portion 40 of the fusing terminals 38A to 38C, and a holding portion 48 are provided. , 48 and a groove 49 that extends radially outward and exposes the bent piece 41 to allow deformation in the radial direction. Further, the portions where the receiving portions 39A to 39C are formed in the front insulator 24 are covered with the nuts 37A to 37C except for the front surfaces of the receiving portions 39A to 39C, and the front surface is positioned on the same plane as the receiving portions 39A to 39C. Projections 50 are formed. Furthermore, a fitting recess 51 having a bottomed hole 52 formed at the bottom is formed at a position symmetrical to the left upper projection 50.
The pair of fusing terminals 38A to 38C of the short-circuit fittings 36A to 36C thus insert-molded are respectively positioned on the diagonals of the hexagon and exposed from the front insulator 24, and the receiving portions 39A to 39C are disposed on the front surface. Only is exposed from the front insulator 24.

  The coil 26 wound around each tooth 30 of the stator core 23 is formed by winding one wire around the teeth 30 adjacent in the circumferential direction in order. The connecting wire 53 between the coils 26 and 26 adjacent to each other in the circumferential direction is passed between the inner plate portion 40 and the bent piece 41 of each of the fusing terminals 38A to 38C. Fusing is performed in a state where the connecting wire 53 is sandwiched between the inner plate portion 40 and the inner plate portion 40 while being bent. The starting end S and the end E (FIG. 6) of the wire are fused by a fusing terminal 38C at the lower end of the short-circuit fitting 36C. As a result, the crossover wires 53 between the diagonal coils 26 and 26 are short-circuited by the short-circuit fittings 36A to 36C via the fusing terminals 38A to 38C, and the three short-circuit fittings 36A to 36C. Between the two coils 26, 26, a delta connection state is established in which the coils are connected in parallel.

  Next, the rear insulator 25 is also in a ring shape having the same diameter as the stator core 23, and protrudes toward the axial center side on the inner peripheral side, and is provided with six projecting portions 55, 55, which are continuously located behind the teeth 30 of the stator core 23. -Forming. Further, on the front side of the rear insulator 25, six fitting portions 56, 56,... That fit into the slots 31 of the stator core 23 are projected. Further, curved lateral cutout portions 57, 57 are formed on the left and right side portions of the rear insulator 25, and chamfered portions 58, 58 that are cut out linearly are formed at the upper and lower centers.

As shown in FIG. 11, the sensor circuit board 27 has three rotation detection elements 60, 60,... Such as a Hall element that detects the position of the permanent magnet 88 provided on the rotor 22 and outputs a rotation detection signal on the back surface. A ring-shaped disk to be mounted, and projecting pieces 61 and 61 projecting outward in the radial direction are formed on the outer periphery on the outer periphery, and the detection signal of the rotation detecting element is sent to the back surface of the lower projecting piece 61. A lead-out portion 62 is provided for drawing the signal lines 63, 63,. Similarly, on the upper right side of the outer periphery, there is provided a positioning piece 64 that protrudes radially outward and has a through hole 65 at the tip.
Further, at the inner peripheral edge of the sensor circuit board 27, two notches 66, 66... Are formed on the upper left and right, and on the lower right.

As shown in FIG. 12, the power supply terminal unit 28 is a resin ring body having a diameter slightly larger than the sensor circuit board 27 and thick in the axial direction. The holding recess 71 into which the sensor circuit board 27 is fitted is formed on the back surface including the holding piece 70 in which the pieces 70 are formed. Further, on the outer periphery of the power supply terminal unit 28, a pressing piece 72 having a pin 73 protruding outward in the radial direction corresponding to the positioning piece 64 of the sensor circuit board 27 and having a through hole 65 of the positioning piece 64 is provided. Has been. A cutout portion 74 is provided at the projecting position of the pressing piece 72 on the outer periphery of the holding recess 71 so as to make the holding recess 71 continuous with the pressing piece 72.
Further, locking pieces 75, 75... Are formed on the inner periphery of the power supply terminal unit 28 so as to protrude rearward and lock into the notches 66 of the sensor circuit board 27 from the inside. However, the locking piece 75 may be provided on the outer periphery of the power supply terminal unit 28 and locked to the notch 66 provided on the outer periphery of the sensor circuit board 27.

  The power supply terminal unit 28 is insert-molded with three power supply terminals 76A to 76C. Among these, as shown in FIG. 13, the power terminal 76 </ b> A is located at the lower end below the central hole of the power terminal unit 28, and then rises to the left along the inner periphery of the power terminal unit 28. A tip portion 77A provided with a through-hole 78 at a position that is symmetrical with respect to the piece 72 has a shape protruding outward in the radial direction. Further, the power terminals 76B and 76C are arranged on the left and right sides of the power terminal 76A and have a symmetrical shape in which tip portions 77B and 77C provided with through holes 78 protrude radially outward. .. Are formed on the front surface of the power supply terminal unit 28 to expose the lower end of the power supply terminal 76A and the base end sides of the power supply terminals 76B, 76C. Three concave grooves 80, 80... Extending to the piece 70 are formed.

  Connected to the power terminals 76A to 76C are U-phase, V-phase, and W-phase power lines 81U, 81V, 81W wired from a three-phase bridge circuit of a control circuit board (not shown) provided in the battery mounting portion 4. Is done. The power supply lines 81U, 81V, 81W are respectively routed upward from the lower holding piece 70 through the concave groove 80, and spotted on the power supply terminals 76A to 76C where the upper conductor portions from which the insulation coating has been removed are exposed to the windows 79, respectively. Connected by welding or the like.

(Description of assembly of power supply terminal unit and sensor circuit board)
When the power supply terminal unit 28 is assembled to the front insulator 24, the sensor circuit board 27 is first placed on the back surface, the upper and lower protruding pieces 61 and 61 are aligned with the holding pieces 70 and 70, and the positioning piece 64 is set to the holding piece 72 position. In the combined state, the holding recess 71 is fitted. Then, the pin 73 of the pressing piece 72 passes through the through hole 65 of the positioning piece 64, and each locking piece 75 of the power supply terminal unit 28 is locked to each notch 66 of the sensor circuit board 27. Therefore, the sensor circuit board 27 is temporarily fixed to the power supply terminal unit 28 while being prevented from rotating and coming off.

  In this way, the power supply terminal unit 28 to which the sensor circuit board 27 is temporarily fixed is fitted with the holding piece 72 and the positioning piece 64 in the fitting recess 51 of the front insulator 24, and the pin 73 is inserted into the bottomed hole 52, and the power supply terminal 76A. Is superimposed on the front surface of the front insulator 24 in such a direction that the power terminals 76B and 76C are in contact with the front surfaces of the receiving portions 39B and 39C. In this state, screws 82, 82,... Are inserted from the through holes 78 of the tip portions 77A to 77C of the respective power supply terminals 76A to 76C, and passed through the through holes 42 of the receiving portions 39A to 39C as they are so Screw into 37C. Then, the power supply terminal unit 28 is fixed to the front insulator 24, and the power supply terminals 76A to 76C are electrically connected to the short-circuit fittings 36A to 36C. Therefore, the power supply lines 81U, 81V, 81W are electrically connected to the short-circuit fittings 36A-36C via the power supply terminals 76A-76C. The sensor circuit board 27 is clamped and fixed between the power terminal unit 28 and the front insulator 24 at the same time as the power terminal unit 28 is screwed. At this time, since the through hole 45 provided in the short-circuit fitting 38B is positioned behind the nut 37A of the short-circuit fitting 36A, the screw 82 screwed into the nut 37A does not contact the short-circuit fitting 38B.

As described above, the assembly of the sensor circuit board 27 and the power supply terminal unit 28 is a simple operation of screwing the power supply terminal unit 28 to which the sensor circuit board 27 is temporarily fixed to the front insulator 24.
As shown in FIG. 2, the stator 21 assembled in this way holds the outer periphery of the stator core 23 by support ribs 85, 85... Protruding in the circumferential direction on the inner surfaces of the half housings 6 a and 6 b of the main body housing 6. At the same time, projections (not shown) projecting on the inner surface of the half housing 6a are fitted in positioning recesses 34 and notches 35 formed in the front insulator 24, respectively, so that they are positioned in the axial direction and the circumferential direction. Be contained.

On the other hand, as shown in FIG. 2, the rotor 22 includes a rotating shaft 86 positioned at the axial center, a cylindrical rotor core 87 disposed around the rotating shaft 86, and permanent magnets 88 inserted and fixed to the rotor core 87. 88...
The rear end of the rotary shaft 86 is pivotally supported by a bearing 89 held by the rear cover 9, and a centrifugal fan 90 is attached to the front portion thereof. Here, the central portion of the centrifugal fan 90 swells forward in a mortar shape, and the bearing 89 protrudes rearward. As a result, the distance between the rear cover 9 and the centrifugal fan 90 is reduced, leading to a reduction in the overall length. .. (FIG. 1) are formed on the left and right side surfaces of the main body housing 6, and exhaust ports 92, 92... Are formed on the left and right side surfaces of the rear cover 9.

In FIG. 2, a gear case 93 that houses the planetary gear reduction mechanism 94 is provided in front of the brushless motor 20, and the front end of the rotating shaft 86 passes through a cap 95 that closes the rear end of the gear case 93. Then, it is pivotally supported by a bearing 96 held by the cap 95. A pinion 97 is fixed to the front end of the rotating shaft 86.
The planetary gear speed reduction mechanism 94 has a well-known structure in which a plurality of carriers 99 supporting a plurality of planetary gears 100 and 100 revolving in the internal gear 98 are arranged in parallel in the axial direction. 98A) is fixed in the gear case 93 and revolves the second stage planetary gear 100, and the second stage planetary gear 100 and the first stage carrier 99 are simultaneously meshed with each other. The carrier 99 and the planetary gear 100 are provided so as to be able to move back and forth in the axial direction between the carrier 99 and the planetary gear 100 so as to cancel the second-stage deceleration. A speed switching ring 102 is coupled to the internal gear 98A via a pin 101, and a protrusion 103 at the upper end of the speed switching ring 102 is coupled to a speed switching button 105 via front and rear coil springs 104, 104. Therefore, if the internal gear 98A is moved back and forth via the speed switching ring 102 by a forward / backward sliding operation of the speed switching button 105, the low speed mode at the forward position and the high speed mode at the reverse position can be selected. Become.

(Explanation of driver drill operation)
In the driver drill 1 configured as described above, when the trigger 15 is pushed in, the switch is turned on and the brushless motor 20 is driven by the power supply of the battery pack 5. That is, the microcomputer mounted on the control circuit board obtains the rotation detection signal indicating the position of the permanent magnet 88 of the rotor 22 output from the rotation detection element 60 of the sensor circuit board 27 to obtain the rotation state of the rotor 22 and obtain The rotor 22 is rotated by controlling ON / OFF of each switching element in accordance with the rotated state, and passing a three-phase current to each coil 26 of the stator 21 in order. Accordingly, the rotation shaft 86 rotates and the rotation reduced by the planetary gear reduction mechanism 94 is transmitted to the spindle to rotate the chuck 13. Then, by operating the mode switching ring 11, it is possible to select a driver mode in which the clutch mechanism in which the rotation transmission is interrupted with a predetermined torque functions and a drill mode in which the clutch mechanism does not function. The torque at which the clutch mechanism operates in the mode can be adjusted.

Here, since the connecting wire 53 between the coils 26 and 26 adjacent to each other in the circumferential direction of the brushless motor 20 is short-circuited diagonally to form a so-called para-winding state, the winding resistance is reduced and a large current flows. be able to. This para-winding state can be achieved by insert-molding the short-circuit fittings 36A to 36C provided with the fusing terminals 38A to 38C electrically connected to the crossover wires 53 and 53 between the diagonals, to the front insulator 24. The axial length is shortened, which can be realized in a space-saving manner.
Moreover, since the six coils 26 are wound with one wire (so-called one-stroke writing), all the coils 26 can be wound in one step.

(Effect of invention relating to brushless motor)
Thus, according to the driver drill 1 of the said form, it is provided with the connection part (fusing terminal 38A-38C) electrically connected with the crossover wires 53 and 53 between the coils 26 and 26, and the crossover wires 53 and 53 Since the short-circuit fittings 36A to 36C for short-circuiting each other are insert-molded in the front insulator 24, when the stator 21 is manufactured, it is not necessary to assemble the short-circuit fittings 36A to 36C to the front insulator 24. It leads to reduction.
In particular, since the nuts 37A to 37C for electrically connecting the power lines 81U, 81V, 81W for supplying power to the coil 26 to the short-circuit fitting 36 and assembling the front insulator 24 are also insert-molded in the front insulator 24, Assembling and detaching of the power lines 81U, 81V, 81W can be easily performed, and workability related to repair and the like is improved.

In addition, since the connecting portions are the fusing terminals 38A to 38C, the crossover wire 53 can be easily and reliably electrically connected.
Further, since the power terminals 76A to 76C of the power terminal unit 28 including the power terminals 76A to 76C to which the power lines 81U, 81V, 81W are electrically connected are screwed to the nuts 37A to 37C, the power lines It is a rational configuration in which 81U, 81V, 81W can be assembled and electrically connected at the same time.
Since the sensor circuit board 27 for detecting the rotation of the rotor 22 is temporarily fixed to the surface of the power terminal unit 28 on the front insulator 24 side, the sensor circuit board 27 is assembled at the same time as the power terminal unit 28 is assembled. This also makes it possible to simplify the work.
In addition, since the power terminal unit 28 has a ring shape and is in contact with the sensor circuit board 27 over the entire circumference, the sensor circuit board 27 is stably held in the assembled state, and highly accurate rotation detection is possible. It becomes.
On the other hand, when the sensor circuit board 27 or the power supply terminal unit 28 needs to be replaced, the sensor circuit board 27 and the power supply terminal unit 28 can be easily detached from the stator 21 by removing the screws 82. Therefore, the structure has good repairability.

And the metal fitting (short-circuit metal fittings 36A-36C) electrically connected to the crossover wire 53 between the 1st coil 26 and the 2nd coil 26 is insert-molded by the front insulator 24, and stator At the time of manufacturing 21, the work of assembling the short-circuit brackets 36A to 36C to the front insulator 24 becomes unnecessary, leading to reduction in the number of parts and the number of assembly steps.
In addition, nuts 37A to 37C are insert-molded in the front insulator 24, and the sensor circuit board 27 and the power supply terminal unit 28, which are other members, can be screwed to the front insulator 24 using the nuts 37A to 37C. Other members can be easily attached and detached, leading to a reduction in the number of parts and assembly man-hours, and the repairability is also improved.

(Explanation of changes)
The shape of the short-circuit metal fitting is not limited to the above form. 14-16 shows the example of a change of the fusing terminal 38A-38C of each short circuit metal fitting 36A-36C, and does not fold and form the bending piece 41a from the rear end of the inner-plate part 40 here, but an inner-plate part 40 is formed to extend forward from the front end of 40. Therefore, in this modified example, when the stator 21 is assembled, with the connecting wire 53 passing outside the inner plate portion 40, the bent piece 41 a is folded back from the outside to sandwich the connecting wire 53, Jing.
Further, the front and rear positions of the short-circuit fittings, the bent shape, the number of short-circuit fittings, and the like are not limited to the above-described forms and modification examples, and can be appropriately changed according to the number of coils, the connection pattern, and the like. The connecting portion with the crossover is not limited to the fusing terminal, and soldering, spot welding, or the like can be employed.

Furthermore, in the above embodiment, the sensor circuit board is temporarily fixed to the power supply terminal unit and is assembled by screwing the power supply terminal unit to the front insulator. However, the sensor circuit board as a separate member is directly fixed to the front insulator by screws. You may make it do. In this case, it can be fixed to the front insulator more firmly and with high accuracy. Further, by using the insert molded nut, the sensor circuit board can be repeatedly attached and detached.
The nut is not limited to a structure in which a separate one is insert-molded, and the nut may be omitted by welding the nut to the short-circuit fitting in advance or by threading the cylindrical portion drawn into the short-circuit fitting. it can.

On the other hand, the overall shape of the power supply terminal unit and the position and shape of the power supply terminal can be changed as appropriate. For example, the overall shape is not a ring shape, but a semicircular or C shape in front view, It is possible to set the direction upward or laterally.
Moreover, in the said form, although the short-circuit metal fitting is insert-molded to the front insulator, it is also possible to insert-mold to the rear insulator. In the above embodiment, the brushless motor is arranged in the front-rear direction, but the insulator is naturally not limited to the front-rear depending on the arrangement form of the motor.

  FIG. 17 shows an example in which a short-circuit metal fitting is insert-molded in the rear insulator. In the stator 21A shown in FIG. 17A, the six coils 26, 26,. Arranged in the order of U2, V2, and W2. The U-phase coils U <b> 1 and U <b> 2 are diagonally positioned with a single wire, and are connected by a crossover U <b> 53 (dotted line) wired along the outer periphery of the rear insulator 25. Similarly, the V-phase coils V1 and V2 are also formed by a single wire positioned diagonally and connected by a crossover V53 (one-dot chain line) wired along the outer periphery of the rear insulator 25. . The W-phase coils W1 and W2 are also formed by one wire positioned diagonally, and are connected by a jumper wire W53 (two-dot chain line) wired along the outer periphery of the rear insulator 25.

The rear insulator 25 is insert-molded with a short-circuit fitting 36D for collectively short-circuiting the three connecting wires U53, V53, and W53. Three connecting wires U53, V53, and W53 are respectively passed to the short-circuit fitting 36D and are short-circuited by fusing to form a neutral point. As shown in FIG. A star connection in which 26 and 26 are connected in parallel is formed. Here, the coil 26 of the other phase which is a 3rd coil is located between the coils 26 and 26 of each phase located diagonally.
In the case of this connection pattern, the sensor circuit board 27 may be screwed to the front insulator 24 and six switching elements may be arranged on the sensor circuit board 27. In this case, the ends of the six coils 26 are connected to the sensor circuit board 27, respectively.

In addition, the motor is not limited to brushless, and the present invention can be applied to other motors that do not use a sensor circuit board. Further, the metal fitting to be insert-molded into the insulator is not limited to the one that short-circuits the crossover wire, and other members other than the sensor circuit board and the power supply terminal unit can be attached to and detached from the insert-molded nut.
The power tool is not limited to a driver drill, but may be an impact driver, a marnoco, a grinder, or an AC machine that uses a commercial power supply instead of a battery pack.
However, the present invention is not limited to electric tools, but can also be applied to garden tools such as blowers, cleaners, dust collectors, high pressure washers, compressors, pumps, transport vehicles, and other electric devices.

  1 ... Driver drill, 2 ... Main body, 6 ... Main body housing, 20 ... Brushless motor, 21,21A ... Stator, 22 ... Rotor, 23 ... Stator core, 24 ... Front insulator, 25 ... Back Insulator, 26 ... Coil, 27 ... Sensor circuit board, 28 ... Power supply terminal unit, 36A to 36C, 36D ... Short-circuit fitting, 37A to 37C ... Nut, 38A to 38C ... Fusing terminal, 39A to 39C ..Receiving part, 40..Inner plate part, 40, 41a..Bending piece, 53, U53, V53, W53..Transfer wire, 61..Projection piece, 63..Signal line, 64..Positioning piece ..70..Holding piece 71..Holding recess 72..Pressing piece 76A to 76C..Power terminal, 77A to 77C..Tip, 81U, 81V, 81W..Power line 86. Axis of rotation, 87 ... rotor core, 88 ... permanent magnet.

Claims (10)

An electric tool having a motor composed of a stator and a rotor, wherein a plurality of coils are wound around the stator via insulators positioned in front and back in the axial direction,
A power tool comprising a connecting portion electrically connected to the connecting wire between the coils and short-circuiting the predetermined connecting wires, the insert being formed in the insulator.   The power tool according to claim 1, wherein a nut for electrically connecting a power line for supplying power to the coil to the short-circuit metal fitting and assembling the nut to the insulator is insert-molded in the insulator.   The power tool according to claim 2, wherein the connection portion is a fusing terminal.   The power tool according to claim 2 or 3, wherein the power terminal of a power terminal unit including a power terminal to which the power line is electrically connected is screwed to the nut.   The power tool according to claim 4, wherein a sensor circuit board for detecting rotation of the rotor is temporarily fixed to a surface of the power supply terminal unit on the insulator side.   The electric power tool according to claim 5, wherein the power terminal unit is ring-shaped and is in contact with the sensor circuit board over the entire circumference. An electric tool having a motor composed of a stator and a rotor, wherein at least a first coil and a second coil are wound around the stator via insulators positioned in the axial direction;
A power tool characterized in that a metal fitting electrically connected to a connecting wire between the first coil and the second coil is insert-molded in the insulator.   The power tool according to claim 7, wherein the first coil and the second coil are adjacent to each other in the circumferential direction of the stator.   The power tool according to claim 7, wherein a third coil is wound between the first coil and the second coil. An electric tool having a motor composed of a stator and a rotor, wherein at least a first coil and a second coil are wound around the stator via insulators positioned in the axial direction;
A power tool, wherein a nut is insert-molded in the insulator, and another member can be screwed to the insulator using the nut.

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