JP2020188631A - Electric work machine - Google Patents

Abstract

To reliably and stably perform insulation protection for a stator core of a coil including a crossover.SOLUTION: The impact driver 1 has a brushless motor 10 including a stator 23 having a stator core 25, front and rear insulators 26, 27 fixed to the stator core 25, multiple coils 28, 28 ... fixed to the front and rear insulators 26, 27, and a ring body 36 and an adhesive A for insulating and protecting a crossover 32 and each coil 28 on the rear insulator 27 and a rotor 24 rotatable relative to the stator 23.SELECTED DRAWING: Figure 3

Description

The present invention relates to an electric working machine such as an impact driver.

Brushless motors are often used as drive sources in electric work machines such as impact drivers. As disclosed in Patent Document 1, this brushless motor has a stator and a rotor that can rotate with respect to the stator. The stator has a coil on a stator core made of a laminated steel plate via an insulator made of an insulating material. It is known that it is wound.

JP-A-2018-137843

In such a brushless motor, no additional machining is basically performed on the wound coil or the wire (crossover wire) connecting the coils.
However, in an electric work machine using a brushless motor, it is necessary to maintain insulation between the coil and the crossover wire and the stator core when water or dust enters from the outside. Therefore, it is conceivable to apply an adhesive to the coil and the crossover wire, but when the adhesive is applied, it may protrude from the insulator, or the coating amount or coating range may become uneven, resulting in insufficient insulation protection. There is a risk. In particular, the crossover is not wound in a clean arc shape, the outer circumference is uneven, and the adhesive area is small, so that it takes time and effort to apply the adhesive.

Therefore, an object of the present invention is to provide an electric working machine capable of reliably and stably performing insulation protection for the stator core of a coil including a crossover wire.

In order to achieve the above object, the invention according to claim 1 comprises a stator core, an insulator fixed to the stator core, a plurality of coils fixed to the insulator, and an insulating means for insulating and protecting each coil on the insulator. With a stator with,
It is characterized by having a brushless motor including a rotor that can rotate with respect to the stator.
According to a second aspect of the present invention, in the configuration of the first aspect, the insulating means includes a resin ring body surrounding the outside of each coil including a crossover wire connecting the coils, and the coil and the crossover wire inside the ring body. It is characterized by containing an adhesive applied to the surface of the coil.
The invention according to claim 3 is characterized in that, in the configuration of claim 2, the ring body is fitted to an insulator and positioned.
According to the fourth aspect of the present invention, in the configuration of the second or third aspect, a plurality of guide ribs for guiding the crossovers are erected concentrically on the insulator, and the ring body surrounds the outside of the guide ribs in a non-contact manner. It is characterized in that the adhesive is filled between the guide rib and the ring body and applied to the surface of the crossover.

According to the present invention, by adopting the insulating means for insulatingly protecting each coil on the insulator, the insulating protection for the stator core of the coil including the crossover can be surely and stably performed.

It is a side view of an impact driver. It is a central vertical sectional view of an impact driver. It is an enlarged view of the brushless motor part of FIG. It is an exploded perspective view of a stator and a ring body. In the explanatory view of the ring body, (A) shows the back surface, (B) shows the front surface, and (C) shows the cross section along the AA line.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a side view of a rechargeable impact driver which is an example of an electric work machine, and FIG. 2 is a central vertical sectional view.
The impact driver 1 has a main body portion 2 whose central axis is in the front-rear direction, and a grip portion 3 that projects downward from the main body portion 2. The housing of the impact driver 1 is attached to the main body housing 4 in which the tubular motor housing 5 forming the main body 2 and the grip housing 6 forming the grip 3 are connected and screwed to the rear end of the motor housing 5. It is composed of a rear housing 7 to be mounted and a hammer case 8 to be assembled to the front portion of the motor housing 5. The main body housing 4 is divided into left and right half housings 4a and 4b, and is assembled by screws 9, 9, ... From the right side.

The main body 2 is provided with a brushless motor 10, a planetary gear reduction mechanism 11, a spindle 12, and a striking mechanism 13 in this order from the rear. The brushless motor 10 is housed in the motor housing 5 and the rear housing 7, the planetary gear reduction mechanism 11, the spindle 12, and the striking mechanism 13 are housed in the hammer case 8, and the anvil 14 serving as the output unit provided in the striking mechanism 13 is provided. It protrudes forward from the front end of the hammer case 8.
A switch 15 having a trigger 16 protruding forward is housed in the upper part of the grip part 3, and a battery mounting part 17 to which a battery pack 18 serving as a power source is mounted is formed in the lower end of the grip part 3. .. A terminal block 19 electrically connected to the battery pack 18 and a controller 20 located above the terminal block 19 are housed in the battery mounting portion 17. The controller 20 is provided with a control circuit board 21 on which a microcomputer, a switching element, and the like are mounted. The upper surface of the battery mounting portion 17 is electrically connected to the control circuit board 21 to increase the number of rotations of the brushless motor and the battery pack. A display panel 22 for displaying the remaining amount of 18 is provided.

The brushless motor 10 is an inner rotor type having a stator 23 and a rotor 24. First, as shown in FIGS. 3 and 4, the stator 23 includes a stator core 25 formed by laminating a plurality of steel plates, a front insulator 26 and a rear insulator 27 provided before and after the stator core 25, and a front insulator 26 and a rear insulator 27. A plurality of coils 28, 28, and the like wound around the stator core 25 via the motor housing 5 are held in the motor housing 5. The front insulator 26 is provided with a plurality of fusing terminals 29 for fusing with the wire of the coil 28 sandwiched at one end, and the other end of each fusing terminal 29 projects downward from the lower end of the front insulator 26. It is routed to the connecting piece 30. A U-shaped terminal unit 31 in a side view, which is wired from the controller 20 and soldered with lead wires corresponding to each fusing terminal 29, is screwed to the connecting piece 30 so as to be sandwiched from below and electrically connected. Has been done. The three-phase power line drawn from the terminal unit 31 passes through the grip portion 3 behind the switch 15 and is connected to the control circuit board 21 in the controller 20.

On the other hand, in the rear insulator 27, the rear view arc-shaped guide ribs 33, 33, which guide the crossover wire 32, which is one wire connecting the coils 28, 28, are concentrically spaced in the circumferential direction at equal intervals. Protruding, the crossover 32 is positioned outside the guide rib 33. Between the guide ribs 33 and 33, the crossover line 32 becomes straight portions 32a, 32a ... Stretched in a straight line. Further, chamfered portions 34, 34 extending in the left-right direction are formed above and below the rear insulator 27 to expose the rear surface of the stator core 25. Further, on the left and right sides of the rear insulator 27, two notches 35A and 35A located on the radial outer side of the straight portions 32a and 32a and positions on the rear extension of the axial concave groove 25a provided on the outer circumference of the stator core 25. A notch 35B is formed. The front protrusion 26a provided on the rear surface of the front insulator 26 and the rear protrusion 27a provided on the front surface of the rear insulator 27 are fitted into the concave groove 25a, respectively, to position both insulators 26 and 27. There is.

An adhesive is applied to the crossover wire 32 and the coil 28 in order to maintain insulation from other metal parts (particularly the stator core 25), but here, when the adhesive is applied, it protrudes to the outside of the stator core 25. The ring body 36 is fitted to the rear insulator 27 so as not to prevent it. The ring body 36 is made of resin and has an outer diameter larger than the outer diameter of the stator core 25 and an inner diameter smaller than the outer diameter of the stator core 25 and larger than the outer diameter of the guide rib 33, and has a rearward protruding length. The diameter is slightly shorter than the guide rib 33. On the inner peripheral surface of the ring body 36, as shown in FIG. 5, thick-walled portions 37A and 37A whose inner surface becomes a flat surface in accordance with the chamfered portions 34 and 34 provided on the rear insulator 27, and the guide ribs 33, Thick portions 37B and 37B whose inner surface is a flat surface are formed in accordance with the straight portions 32a and 32a between 33. Of these, the thick portion 37B corresponding to the straight portion 32a has a front end shortened by the thickness in the front-rear direction of the rear insulator 27, and the rear insulator 27 is on the inner peripheral surface of the ring body 36 on the front surface of the thick portion 37B. Positioning protrusions 38A and 38A that fit into the notches 35A and 35A of the above are formed, respectively. Further, at the front end of the ring body 36, a positioning protrusion 38B that fits into the notch 35B and the concave groove 25a is formed. Further, a protrusion 39 projecting outward in the radial direction is formed on the lower surface of the ring body 36. The protrusion 39 is positioned by a receiving portion 5a (FIG. 3) provided in the motor housing 5.

In this ring body 36, the thick portions 37A and 37A are fitted into the chamfered portions 34 and 34, the positioning protrusions 38A and 38A are fitted into the notches 35A and 35A, and the positioning protrusions 38B are fitted into the notches 35B outside the rear protrusion 27a. When they are combined and assembled to the rear insulator 27 from the rear, they are assembled at a position where they abut on the rear surface of the stator core 25 on the radial outer side of the guide rib 33. In this assembled state, as shown in FIG. 3, a gap S larger than the diameter of the crossover 32 is formed between the ring body 36 and the guide rib 33 over the entire circumference.
Therefore, when applying the adhesive to the coil 28 and the crossing wire 32, the adhesive is applied to each coil 28 while the ring body 36 covers the outside of the crossing wire 32, and the guide rib 33 and the ring body 36 are applied. If the adhesive A (FIG. 3) is applied to the gap S formed between the two, the adhesive A can be filled between the guide rib 33 and the ring body 36 to uniformly cover the crossover 32, and the adhesive A can be adhered. The agent A does not protrude to the outside of the ring body 36.

The rotor 24 has a rotating shaft 40 located at the center of the axis, a tubular rotor core 41 arranged around the rotating shaft 40, and a tubular rotor core 41 arranged outside the rotor core 41, and has a tubular shape with alternating polarities in the circumferential direction. It has a permanent magnet 42 and a disk-shaped permanent magnet 43 for a sensor arranged on the front side thereof. A sensor circuit board 44 equipped with three rotation detection elements that detect the position of the sensor permanent magnet 43 of the rotor 24 and output a rotation detection signal is screwed to the front end of the front insulator 26. A signal line for outputting a rotation detection signal is connected to the lower end of the sensor circuit board 44, and this signal line also passes through the grip portion 3 behind the switch 15 and is controlled in the controller 20 like the power supply line. It is connected to the circuit board 21.

The rear housing 7 has a cap shape that is attached from the rear of the motor housing 5 by left and right screws. A bearing 45 is held at the center of the rear inner surface of the rear housing 7, and supports the rear end of the rotating shaft 40. A centrifugal fan 46 for cooling the motor is attached to the rotating shaft 40 in front of the bearing 45. Slit-shaped exhaust ports 47, 47 ... Extending in the circumferential direction are formed on the peripheral surface of the rear housing 7 on the outside of the centrifugal fan 46, and slit-shaped extending in the front-rear direction on the left and right side surfaces of the motor housing 5. Intake ports 48, 48 ... Are formed.

The front end of the rotating shaft 40 penetrates the bearing retainer 50 held in the motor housing 5 in front of the brushless motor 10 and projects forward, and is pivotally supported by the bearing 51 held in the rear portion of the bearing retainer 50. A pinion 52 is attached to the front end of the rotating shaft 40.
The bearing retainer 50 has a metal disk shape having a constricted portion formed in the center, and the rib 53 provided on the inner surface of the motor housing 5 fits into the constricted portion, whereby the bearing retainer 50 restricts movement in the front-rear direction. It is held in the motor housing 5 in this state.
Further, a ring wall 54 having a male screw portion formed on the outer periphery thereof is projected forward from the front peripheral edge of the bearing retainer 50, and a female provided on the inner circumference of the rear end of the hammer case 8 is provided on the ring wall 54. The threaded part is connected.

The hammer case 8 is a metal tubular body in which the front half portion is tapered and the front cylinder portion 55 is formed at the front end, and the rear portion is closed by a bearing retainer 50 serving as a lid. On the lower surface of the hammer case 8, a pair of left and right wall-shaped lower protrusions 56 extending in the front-rear direction are formed, and in the assembled state, holding ribs (not shown) projecting from the inner surfaces of the left and right half housings 4a and 4b. Are in contact with the side surface of the lower protrusion 56, respectively. The rotation of the hammer case 8 is restricted by the engagement between the lower protrusion 56 and the holding rib.
A forward / reverse switching lever 57 of the brushless motor 10 is slidably provided in the main body housing 4 between the hammer case 8 and the switch 15, and the main body housing 4 can switch the striking mode in front of the lever 57. The switch 58 is held in a forward-looking posture with the button portion exposed to the front surface. Here, by repeating the pressing operation of the button portion, the striking force is switched to four stages and the registered striking mode.
Further, on the front side of the motor housing 5, a resin-made and translucent hammer case cover 59 that covers from the front portion of the hammer case 8 to the front cylinder portion 55 is provided, and the outer peripheral portion of the front end of the hammer case cover 59 is provided. , A bumper 60 formed of an elastic body is attached. Lights 61 and 61 equipped with LEDs are provided forward on the left and right sides of the hammer case cover 59 behind the bumper 60, respectively.

A bearing 62 is held in the front portion of the bearing retainer 50, and the rear end of the spindle 12 is pivotally supported by the bearing 62. The spindle 12 has a hollow and disc-shaped carrier portion 63 at the rear portion, and the front end of the rotating shaft 40 and the pinion 52 are projected into a through hole 64 formed from the rear surface to the axial center.
The planetary gear reduction mechanism 11 includes an internal gear 65 having internal teeth and three planetary gears 66, 66 ... Having external teeth that mesh with the internal gear 65. The internal gear 65 is coaxially housed inside the ring wall 54 of the bearing retainer 50, and a detent portion 67 that engages with the inner peripheral surface of the hammer case 8 is provided on the outer peripheral side of the front portion thereof. The planetary gear 66 is rotatably supported in the carrier portion 63 by the pin 68 and meshes with the pinion 52 of the rotating shaft 40.

The striking mechanism 13 includes a hammer 70 externally attached to the spindle 12 and a coil spring 71 for urging the hammer 70 forward. First, the hammer 70 has a pair of claws on the front surface, and is fitted with ceramic balls 73, 73 straddling the cam grooves 72, 72 formed on the inner surface of the hammer 70 and the outer surface of the spindle 12, respectively. Is coupled to the spindle 12 via. A ring-shaped groove 74 is formed on the rear surface of the hammer 70, and the front end of the coil spring 71 is inserted therein. The rear end of the coil spring 71 is in contact with the front surface of the carrier portion 63. A communication hole 75 that communicates orthogonally with the through hole 64 is formed in the spindle 12, and grease in the through hole 64 can be supplied between the hammer 70 and the spindle 12 via the communication hole 75. ..

The anvil 14 is pivotally supported by two front and rear ball bearings 80, 80 held in the front cylinder portion 55 of the hammer case 8. At the rear end of the anvil 14, a pair of arms 81 and 81 that engage with the claws of the hammer 70 in the rotational direction are formed.
An intermediate washer 82 is interposed between the ball bearings 80 and 80, and the intermediate washer 82 comes into contact with the outer ring of the ball bearings 80 and 80, respectively, so that a predetermined distance is provided between the ball bearings 80 and 80. keeping.
The outer diameters of the ball bearing 80 and the intermediate washer 82 are the same, and a ring-shaped positioning portion 83 is provided around the front end of the front cylinder portion 55, and the outer ring of the ball bearing 80 on the front side is the positioning portion 83. Positioning is achieved forward by contacting with. Further, behind the ball bearing 80 on the rear side, a rear washer 84 for positioning the ball bearing 80 to the rear is provided. After that, the washer 84 has an outer diameter larger than that of the ball bearing 80, fits on the inner peripheral surface of the front cylinder portion 55, and is in contact with the outer ring of the ball bearing 80.

Further, on the inner peripheral side of the rear surface of the front cylinder portion 55 in front of the arm 81, a ring-shaped holding portion 85 having an inner diameter smaller than the outer diameter of the rear washer 84 and an outer diameter larger than the outer diameter of the rear washer 84 is coaxial. A resin outer washer 86 having a thickness such that the rear surface is located behind the holding portion 85 is fitted to the outside of the holding portion 85. The outer washer 86 receives the arms 81 and 81.
Further, two O-rings 87 and 87 are provided in the front and rear of the ball bearings 80 and 80 in the anvil 14, and are in contact with the inner rings of the ball bearings 80 and 80, respectively.
A fitting recess 89 into which a fitting projection 88 provided on the front end axial center of the spindle 12 is fitted is formed in the rear axial center of the anvil 14. The through hole 64 of the spindle 12 communicates with the fitting recess 89 and supplies grease to the fitting recess 89 to lubricate the spindle 12 and the anvil 14.

On the other hand, at the axial center of the anvil 14, an insertion hole 90 having a hexagonal cross section into which a bit can be inserted from the front is formed as an opening from the front end.
Further, the balls 91 and 91 that can appear and disappear in the insertion hole 90 are housed in the anvil 14, and can be engaged with the bit at the protruding position to prevent the balls from coming off. This protruding position is maintained by the operation sleeve 92 externally attached to the tip of the anvil 14, and when the operation sleeve 92 is slid forward, the pressure on the balls 91 and 91 is released and the bit can be pulled out.

In the impact driver 1 configured as described above, when a bit (not shown) is attached to the anvil 14 and then the trigger 16 is pushed in to turn on the switch 15, power is supplied to the brushless motor 10 to rotate the rotating shaft 40. That is, the microcomputer of the control circuit board 21 obtains a rotation detection signal indicating the position of the sensor permanent magnet 43 of the rotor 24 output from the rotation detection element of the sensor circuit board 44, acquires the rotation state of the rotor 24, and acquires the rotation state. The rotor 24 is rotated by controlling ON / OFF of each switching element according to the rotation state and passing a current through each coil 28 of the stator 23 in order.

When the rotating shaft 40 rotates together with the rotor 24, the planetary gear 66 that meshes with the pinion 52 revolves in the internal gear 65, and the spindle 12 is decelerated and rotated via the carrier portion 63. Therefore, the hammer 70 also rotates and the anvil 14 is rotated via the arms 81 and 81 with which the claws are engaged, and the screw can be tightened by the bit. At this time, since the anvil 14 is pivotally supported by two front and rear ball bearings 80, 80, rattling of the anvil 14 is suppressed, and the bit at the tip is less likely to swing.
As the screw tightening progresses and the torque of the anvil 14 increases, the hammer 70 retreats against the urging of the coil spring 71 while rolling the balls 73 and 73 along the cam groove 72 of the spindle 12, and the claws move to the arm. When separated from 81, 81, the hammer 70 rotates while advancing by the urging of the coil spring 71 and the guidance of the cam groove 72, and the claw is engaged with the arms 81 and 81 again, and the anvil 14 is subjected to a rotational impact force (impact). ) Is generated. Further tightening is possible by repeating this process.

On the other hand, when the centrifugal fan 46 rotates with the rotation of the rotating shaft 40, outside air is sucked from the intake port 48, passes through the motor housing 5, cools the brushless motor 10, and then sent to the outside in the radial direction of the centrifugal fan 46. Then, it is discharged to the outside through the exhaust port 47.
Then, even if foreign matter such as water or dust may enter from the exhaust port 47, a ring body 36 is arranged around the coil 28 and the crossover line 32 wound around the insulator 27 after the stator 23. Therefore, it is difficult for foreign matter to enter the inside of the ring body 36. Further, even if foreign matter enters the inside of the ring body 36, the coil 28 and the crossover wire 32 are coated with the adhesive A, so that the insulation is maintained.

As described above, according to the impact driver 1 of the above-described embodiment, the stator core 25, the front and rear insulators 26 and 27 (insulators) fixed to the stator core 25, and the plurality of coils 28 and 28 fixed to the front and rear insulators 26 and 27. A brushless motor including a stator 23 having a ring body 36 and an adhesive A (insulating means) that insulate and protect each coil 28 on the rear insulator 27, and a rotor 24 that is rotatable with respect to the stator 23. By having 10, it is possible to reliably and stably protect the stator core 25 of the coil 28 including the crossover 32 connecting the coils 28 and 28.

In particular, here, the insulating means is a resin ring body 36 that surrounds the outside of each coil 28 including the crossover wire 32, and an adhesive A that is applied to the surfaces of the coil 28 and the crossover wire 32 inside the ring body 36. Since it is assumed that the adhesive A is contained, the adhesive A can be evenly applied without protruding from the rear insulator 27. In addition, since the work difficulty level is reduced, the work time can be reduced and automatic assembly can be performed, which leads to cost reduction.
Further, since the ring body 36 is fitted and positioned in the rear insulator 27, the ring body 36 does not rattle or tilt when the adhesive A is applied, and the adhesive A application work can be performed. It can be done smoothly.
Further, on the rear insulator 27, a plurality of guide ribs 33 for guiding the crossover line 32 are erected concentrically, and the ring body 36 is arranged so as to surround the outside of the guide ribs 33 in a non-contact manner, and the guide ribs 33 and the ring are arranged. Since the adhesive A is filled between the body 36 and the crossover wire 32 and applied to the surface of the crossover wire 32, the adhesive A is surely applied to the crossover wire 32 located in the gap S between the guide rib 33 and the ring body 36. Can be done.

The ring body of the insulating means is not limited to the case of being formed by one member, and may have a structure in which a plurality of parts are combined, for example, a combination of semicircular ones divided into two in the axial direction. The number, shape, arrangement, etc. of thick parts and positioning protrusions can be changed as appropriate, and some of them can be omitted. Further, instead of these shapes, a step portion may be provided on the inner peripheral surface of the ring body to be fitted to the insulator.
Further, in the above embodiment, the ring body is made of resin, but a flexible tape-shaped body may be wound around the outside of the coil and the crossover. In this case, it may be wound multiple times instead of single. However, as compared with tape winding, the resin ring body has a more stable adhesive application amount and application range, and the work difficulty is lower, so that the occurrence rate of defective motors is lower.
In the above embodiment, the insulating means is provided only on the rear insulator, but it can also be provided on the front insulator.

On the other hand, although the description is given based on the impact driver in the above embodiment, the present invention is not limited to the impact driver, but other electric tools such as driver drills, reciprocating saws, hammer drills, gardening tools such as lawnmowers, and compressors. It can also be applied to working machines. Further, the present invention can be adopted not only for a rechargeable type but also for an AC machine that does not use a battery pack as a power source.

1 ... Impact driver, 2 ... Main body, 3 ... Grip, 4 ... Main body housing, 5 ... Motor housing, 6 ... Grip housing, 7 ... Rear housing, 8 ... Hammer case, 10 ...・ Brushless motor, 11 ・ ・ planetary gear reduction mechanism, 12 ・ ・ spindle, 13 ・ ・ striking mechanism, 14 ・ ・ anvil, 20 ・ ・ controller, 23 ・ ・ stator, 24 ・ ・ rotor, 25 ・ ・ stator core, 26 ・・ Front insulator, 27 ・ ・ Rear insulator, 28 ・ ・ Coil, 32 ・ ・ Crossing wire, 33 ・ ・ Guide rib, 35A, 35B ・ ・ Notch, 36 ・ ・ Ring body, 37A, 37B ・ ・ Thick part, 38A , 38B ... Positioning protrusion, 40 ... Rotating shaft, 46 ... Centrifugal fan, 47 ... Exhaust port, 48 ... Intake port, 70 ... Hammer, 71 ... Coil spring, S ... Gap, A ... Adhesive Agent.

Claims (4)

A stator having a stator core, an insulator fixed to the stator core, a plurality of coils fixed to the insulator, and an insulating means for insulating and protecting each of the coils on the insulator.
An electric working machine having a brushless motor including a rotor rotatable with respect to the stator. The insulating means includes a resin ring body that surrounds the outside of each coil including a crossover wire connecting the coils, and an adhesive applied to the surface of the coil and the crossover wire inside the ring body. The electric working machine according to claim 1, further comprising. The electric work machine according to claim 2, wherein the ring body is fitted and positioned in the insulator. A plurality of guide ribs for guiding the crossovers are erected concentrically on the insulator, and the ring body is arranged so as to surround the outside of the guide ribs in a non-contact manner, and the guide ribs and the ring body are connected to each other. The electric working machine according to claim 2 or 3, wherein the adhesive is filled in between and applied to the surface of the crossover.

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