JP2017007032A - Electric tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric tool which is not subject to limitations on the size of a bearing of a rotary shaft.SOLUTION: An impact driver 1 has: a motor 12 including a stator 19 and a rotor 20 having a rotary shaft 35; a sensor circuit board 44 through which the rotary shaft 35 penetrates in an orthogonal direction; and a motor housing 17 housing the motor 12 and the sensor circuit board 44. The sensor circuit board 44 is provided with: a through hole 48 of the rotating shaft 35; and a slit 49 communicating with the through hole 48 and allowing the rotary shaft 35 to pass therethrough in a radial direction so that the sensor circuit board 44 can be assembled to the stator 19 in a state where the motor 12 is stored in a half-split housing 17a.SELECTED DRAWING: Figure 2

Description

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

  As an electric power tool such as an impact driver, one using a brushless motor as a drive source is known as shown in Patent Document 1. The brushless motor includes a stator around which a plurality of coils are wound, and a rotor having a rotation shaft, and the stator detects a position of a sensor magnet provided on the rotor and outputs a rotation detection signal. The sensor circuit board on which is mounted is fixed. This sensor circuit board has a disk shape having a through hole through which the rotation axis of the rotor penetrates in the orthogonal direction.

Japanese Patent Laying-Open No. 2015-51482

  In such an electric tool, the assembly of the brushless motor is in the order of penetrating a rotor in which a bearing such as a ball bearing is assembled to the rotating shaft while the sensor circuit board is fixed to the stator with screws or the like. Therefore, the size of the bearing is limited so that it can pass through the through-hole of the sensor circuit board, and as a result, the standard (performance) of the brushless motor that can be adopted is limited.

  Accordingly, an object of the present invention is to provide an electric tool that is not restricted by the size of the bearing of the rotary shaft.

In order to achieve the above object, the invention described in claim 1 is a motor including a stator and a rotor having a rotating shaft, a substrate through which the rotating shaft passes in an orthogonal direction, and a first housing that accommodates the motor and the substrate. A housing and a second housing, wherein the substrate can be assembled to any one of the stator, the first housing, and the second housing in a state where the motor is accommodated in the first housing. To do.
In order to achieve the above object, a second aspect of the present invention provides a motor including a stator and a rotor having a rotating shaft, a substrate through which the rotating shaft passes in an orthogonal direction, a housing for housing the motor and the substrate, The substrate has a through-hole of the rotating shaft and a slit that communicates with the through-hole and allows the rotating shaft to pass in the radial direction.
According to a third aspect of the present invention, in the configuration of the first or second aspect, the insulating member provided on the end face of the stator is provided with a positioning portion that can be positioned by sliding the substrate from a direction orthogonal to the rotation axis. It is a feature.
In order to achieve the above object, a fourth aspect of the present invention is directed to a motor including a stator and a rotor having a rotation shaft, a substrate through which the rotation shaft passes in an orthogonal direction, a first motor and a substrate that house the substrate. A positioning unit capable of positioning the substrate by sliding the substrate in a direction orthogonal to the rotation axis in any one of the stator, the first housing, and the second housing. To do.
According to a fifth aspect of the present invention, in the configuration of the fourth aspect, the positioning portion is positioning with respect to the axial direction of the rotation shaft and / or the rotation direction.

  According to the present invention, since the substrate through which the rotating shaft passes can be assembled after the rotor, it is not necessary to pass the bearing of the rotating shaft through the through hole of the substrate. Therefore, there is no restriction on the size of the bearing of the rotating shaft.

It is a longitudinal cross-sectional view of an impact driver. It is an expanded sectional view of a main part. It is a disassembled perspective view of a motor. It is a front view of a motor, (A) shows before attachment of a sensor circuit board, (B) shows after attachment, respectively. It is explanatory drawing of a motor, (A) shows a side surface, (B) shows an AA line cross section, respectively.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view of an impact driver which is an example of an electric tool. The impact driver 1 has a main body portion 2 having a central axis in the front-rear direction and a grip portion 3 protruding downward from the main body portion 2, and the battery mounting portion 4 provided at the lower end of the grip portion 3 includes a power source. The battery pack 5 is mounted. A switch 6 with a trigger 7 protruding forward is accommodated in the upper part of the grip part 3, and a terminal block 8 electrically connected to the battery pack 5 and a microcomputer are mounted on the battery mounting part 4. A controller 9 having a control circuit board (not shown) is provided, and a switch panel 10 having a push button for changing the number of revolutions and a display unit for remaining battery capacity is provided. 11 is a strap.

  FIG. 2 is an enlarged cross-sectional view of the main body 2. The main body 2 accommodates the motor 12, the planetary gear reduction mechanism 13, the spindle 14, the striking mechanism 15, and the anvil 16 in this order from the rear. Projecting forward from the front end of the main body 2. The latter half of the main body 2 has a cylindrical motor housing 17 that houses the motor 12 and is integrated with the grip portion 3. The motor housing 17 and the grip portion 3 are the first and second housings. Are formed by assembling a pair of left and right halved housings 17a, 17b with a plurality of screws 18, 18,.

The motor 12 is an inner rotor type brushless motor having a stator 19 and a rotor 20. First, as shown in FIGS. 3 and 4, the stator 19 includes a stator core 21, a front insulating member 22 and a rear insulating member 23 provided before and after the stator core 21, a front insulating member and a rear insulating member 22. .. Have a plurality of coils 25, 25... Wound around teeth 24, 24.
A plurality of protrusions 26, 26,... Are formed on the front surface of the front insulating member 22, and a part of the protrusions 26A (indicated as “26A” and “26B” when it is necessary to distinguish) is provided on the axial center side. A flat surface 27 on which a sensor circuit board 44 to be described later is placed is formed perpendicular to the axis of the stator 19. On the axial center side of the other protrusion 26B, an inclined surface 28 that is inclined downward as it approaches the axial center is formed.

  Further, each projection 26 in the substantially semicircular portion on the left side except just below is connected by an arc-shaped peripheral wall portion 29 extending forward on the outer peripheral side, and each projection extends to the axial center side at the front end of the peripheral wall portion 29. An arc-shaped belt-like front wall portion 30 that extends from the front is extended to 26. As shown in FIGS. 2 and 5, the peripheral wall portion 29 and the front wall portion 30 form a positioning groove 31 for a substantially half circumference as a positioning portion that opens toward the axial center side in front of each left protrusion 26. Is formed. However, as shown in FIG. 5, a closing portion 32 that closes the positioning groove 31 and divides it vertically is formed at an intermediate portion of the positioning groove 31 that is directly adjacent to the left side of the axis of the stator 19. 33 are through holes formed in the left peripheral surface of the front insulating member 22 by the space between the left projections 26, 26,. On the other hand, on the rear surface of the rear insulating member 23, a plurality of insulating ribs 34, 34,.

  The rotor 20 is disposed on the outer side of the rotating shaft 35 positioned at the shaft center, the cylindrical rotor core 36 disposed around the rotating shaft 35, and is cylindrical and has a polarity in the circumferential direction. The permanent magnets 37, 37,... Which are alternately changed and a plurality of sensor permanent magnets 38, 38,. A pinion 39 is attached to the front end of the rotating shaft 35, and a bearing (here, a ball bearing) 40 is assembled to the rear thereof. A centrifugal fan 41 is attached to the rear end of the rotating shaft 35, and a bearing is attached to the rear thereof. A (ball bearing here) 42 is assembled. The centrifugal fan 41 here is a bulging portion 43 whose central portion bulges forward in a bowl shape, and the bearing 42 overlaps the centrifugal fan 41 in the radial direction immediately behind the bulging portion 43. Are arranged as follows.

  At the front end of the front insulating member 22, a sensor circuit board 44 mounted with three rotation detection elements 45, 45... For detecting the position of the sensor permanent magnet 38 of the rotor 20 and outputting a rotation detection signal is attached. It is done. The sensor circuit board 44 includes a disk part 46 having the same outer diameter as the inner diameter of the positioning groove 31 of the front insulating member 22, and a connection part 47 protruding from the disk part 46 radially outward in a tongue-like shape. The disk portion 46 has a C-shape in a front view including a through hole 48 formed in the center and a slit 49 that communicates with the through hole 48 and is formed right next to the left side. The width of the slit 49 is such that the closing portion 32 of the front insulating member 22 is fitted. 50, 50... Are a plurality of lead wires connected to the connection portion 47, and include two types of outputs for outputting a rotation detection signal from the rotation detection element 45 and for a power source to which the terminal of the coil 25 is connected. It is.

  When the sensor circuit board 44 is slid from the right side of the front insulating member 22 toward the peripheral wall portion 29 in a direction orthogonal to the axis of the stator 19 as shown in FIG. As shown in (B), the slide is restricted at a position where the disc portion 46 abuts on the positioning groove 31 and the left end surface 47 a of the connecting portion 47 abuts on the right end surface 29 a of the peripheral wall portion 29. In this state, the closing portion 32 in the positioning groove 31 is fitted to the slit 49, the sensor circuit board 44 is positioned by contacting the flat surface 27 of the protrusion 26A of the front insulating member 22, and the rotating shaft 35 is a through hole. Located at the center of 48.

  The switching element for switching the energization of the coil 25 is mounted on the controller 9, and the lead wire 50 connected from the controller 9 to the connection portion 47 of the sensor circuit board 44 is drawn backward from the connection portion 47. Then, the grip part 3 is drawn. Therefore, a screw 18 (indicated as “18A” for distinction) for fixing the half housings 17a and 17b below the motor 12 is provided at a rear position so as not to interfere with the lead wire 50. Yes.

The stator 19 is held coaxially with the main body 2 by a circumferential rib 51 projecting from the inner surface of the motor housing 17 and a longitudinal rib 52. On the rear surface of the motor housing 17, a cap-shaped rear cover 53 is attached to a screw boss (not shown) formed on each of the half housings 17 a and 17 b by screws from the rear, and a connecting portion between the motor housing 17 and the rear cover 53. Is formed with a wax joint in which a convex portion 54 formed on the inner peripheral side of the rear end of the half housing 17a, 17b and a concave portion 55 formed on the inner peripheral side of the front end of the rear cover 53 are fitted. .
The rear cover 53 holds a bearing 42 assembled to the rotary shaft 35, and exhaust ports 56, 56... Are formed on the side surface of the rear cover 53 on the radially outer side of the centrifugal fan 41. An air inlet (not shown) is formed outside the sensor circuit board 44 in the radial direction on the side surface of the motor housing 17.

On the other hand, the front end of the rotating shaft 35 passes through the bearing retainer 57 held by the motor housing 17 in front of the motor 12 and protrudes forward, and the bearing 40 is held by the holding portion 58 of the bearing retainer 57.
The bearing retainer 57 is in the shape of a metal disk having a constricted portion 59 formed at the center, and the retaining rib 60 provided on the inner surface of the motor housing 17 is engaged with the constricted portion 59 so that the bearing retainer 57 is moved in the front-rear direction. Is held by the motor housing 17 in a state in which the movement is restricted.
In addition, a ring wall 61 having a male threaded portion formed on the outer periphery is projected forward from the front peripheral edge of the bearing retainer 57, and the spindle 14, the striking mechanism 15, and the anvil 16 are accommodated in the ring wall 61. The hammer case 62 is screwed.

The hammer case 62 is a metal cylindrical body in which the front half portion is tapered to form the front tubular portion 63, and the rear portion is closed with the bearing retainer 57 serving as a lid. A stop projection 64 is formed on the lower surface of the hammer case 62, and in the assembled state, presser ribs (not shown) protruding from the inner surfaces of the left and right half housings 17a and 17b are in contact with the side surfaces of the stop projection 64, respectively. It has become. Further, on the left and right sides of the hammer case 62, a not-shown protrusion on the hammer case 62 side and a not-shown concave groove on the half housings 17a and 17b are fitted. The rotation of the hammer case 47 is restricted by the engagement between the stop protrusion 64 and the holding rib, and the protrusion and the groove.
Between the hammer case 62 and the switch 6, a forward / reverse switching lever 65 of the motor 12 is slidable to the left and right, and an LED 66 for illuminating the front of the anvil 16 is attached obliquely upward in front of the lever. .
Further, a cover 67 is provided in front of the motor housing 17 so as to cover from the front portion of the hammer case 62 to the front cylinder portion 63, and a rubber bumper 68 is attached to the outer periphery of the front end of the cover 67.

The rear end of the spindle 14 is pivotally supported via a bearing 69 at the front portion of the bearing retainer 57. The spindle 14 has a hollow and disk-shaped carrier part 70 at the rear part, and a pinion 39 of the rotary shaft 35 protrudes into a bottomed hole 71 formed in the axial center from the rear surface.
The planetary gear speed reduction mechanism 13 includes an internal gear 72 having internal teeth, and three planetary gears 73, 73... Having external teeth meshing with the internal gear 72. The internal gear 72 is connected to the gear portion 74 coaxially accommodated inside the ring wall 61 of the bearing retainer 57, and is connected to the outer peripheral side of the front portion of the gear portion 74. The front outside 75 engages with the inner peripheral surface of the hammer case 62 and is prevented from rotating, and the axial direction between the ring wall 61 and the step 76 provided on the inner periphery of the hammer case 62 Movement is restricted.

Reference numeral 77 denotes an O-ring interposed between the rear end of the gear portion 74 and the front surface of the bearing retainer 57. The O-ring 77 seals between the internal gear 72 and the bearing retainer 57 and The impact from the gear 72 to the bearing retainer 57 is also reduced.
The planetary gear 73 is rotatably supported in the carrier part 70 of the spindle 14 by a pin 78 and meshes with the pinion 39 of the rotating shaft 35. A ring-shaped rising portion 79 is formed on the outer periphery of the front portion of the carrier portion 70 outside the pin 78.

  The striking mechanism 15 includes a hammer 80 that is externally mounted on the spindle 14 and a coil spring 81 that biases the hammer 80 forward. First, the hammer 80 has a pair of claws (not shown) on the front surface, and is a ball fitted over an outer cam groove 82 formed on the inner surface and an inner cam groove 83 formed on the surface of the spindle 14. It is coupled to the spindle 14 via 84, 84. A ring-shaped groove 85 is formed on the rear surface of the hammer 80, and the front end of the coil spring 81 is inserted therein. The rear end of the coil spring 81 is in contact with the front surface of the carrier portion 70 inside the rising portion 79. A plurality of balls 86, 86... And a washer 87 are accommodated at the bottom of the groove 85 so as to receive the front end of the coil spring 81. Further, a taper portion 88 that increases in diameter as it goes rearward is formed outside the rear end of the groove 85 so as to prevent interference with the rising portion 79 when the hammer 80 is retracted.

The anvil 16 is pivotally supported by a bearing 89 held by the front cylindrical portion 63 of the hammer case 62, and a pair of arms 90, 90 that engage with the claws of the hammer 80 in the rotational direction are formed at the rear end. Yes. A ring-shaped protrusion 91 is provided in front of the arm 90 on the inner peripheral side of the rear surface of the front tube portion 63, and a resin washer 92 that receives the arm 90 is fitted to the outside of the protrusion 91. Yes.
A fitting hole 93 is formed in the rear axis of the anvil 16, and the front end of the spindle 14 is coaxially inserted therein. The spindle 14 is formed with first communication holes 94, 94 in the radial direction that allow the bottomed hole 71 to communicate with the inner peripheral surface of the hammer 80, and the bottomed hole 71 communicates with the fitting hole 93 at the shaft center. The second communication hole 95 is formed so that the grease in the bottomed hole 71 can be supplied into the inner peripheral surface of the hammer 80 and the fitting hole 93.
On the other hand, an insertion hole 96 for receiving a bit (not shown) is formed in the front axis of the anvil 16, and a front end of the anvil 16 includes a ball 97 and a sleeve 98 for preventing the bit inserted into the insertion hole 96 from coming off. A chuck mechanism is provided.

  In the impact driver 1 configured as described above, each component is assembled with the left half housing 17a facing down. At this time, the motor 12 first penetrates the rotor 19 with the pinion 39, the bearings 40 and 42, and the centrifugal fan 41 into the stator 19 before the sensor circuit board 44 is assembled, and the hammer case 62 with the striking mechanism 15 assembled. And the bearing retainer 57 are set on the half housing 17a. Then, the sensor circuit board 44 is inserted into the positioning groove 31 from the direction perpendicular to the axis of the stator 19 (here, the upper side of the half housing 17a) with the slit 49 facing downward. Then, the rotating shaft 35 of the rotor 20 moves relatively in the slit 49 and reaches the through hole 48 without interfering with the disc portion 46, and the sensor circuit board 44 is fitted to the front insulating member by fitting with the closing portion 32. 22 is positioned. Therefore, since the bearing 40 of the rotating shaft 35 does not need to pass through the through hole 48 of the sensor circuit board 44, a bearing having a larger diameter than the through hole 48 can be used.

Then, the half housing 17b is assembled and screwed from above, and the rear cover 53 is screwed to complete the assembly.
In the impact driver 1, when the trigger 7 is pushed in and the switch 6 is turned on, the motor 12 is supplied with power and the rotating shaft 35 rotates. That is, the controller 9 obtains the rotation detection signal indicating the position of the sensor permanent magnet 38 of the rotor 20 output from the rotation detection element 45 of the sensor circuit board 44, acquires the rotation state of the rotor 20, and acquires the rotation state. In response to this, ON / OFF of each switching element is controlled, and the rotor 20 is rotated together with the rotating shaft 35 by causing a current to flow sequentially to each coil 25 of the stator 19.

  Then, the planetary gear 73 meshing with the pinion 39 revolves within the internal gear 72, and the spindle 14 is decelerated and rotated via the carrier part 70. Therefore, the hammer 80 is also rotated to rotate the anvil 16 via the arm 90 with which the claw is engaged, and the screw can be tightened with the bit. When the tightening of the screw is advanced and the torque of the anvil 16 is increased, the hammer 80 moves backward along the inner cam groove 83 of the spindle 14 against the bias of the coil spring 81, and the pawl is moved to the arm 90. When separated from, the hammer 80 rotates while moving forward by the bias of the coil spring 81 and the guide of the inner cam groove 83 to re-engage the claw with the arm 90, thereby generating a rotating impact force (impact) on the anvil 16. . By repeating this, further tightening is possible.

  When the centrifugal fan 41 rotates with the rotation of the rotating shaft 35, the air taken in from the intake port passes through the motor 12 and cools, and then is discharged from the exhaust port 56. When passing through the motor 12, the air that has entered from the air inlet is formed between the projections 26 and 26 on the right side of the through hole 48 and the slit 49 of the disc portion 46 of the sensor circuit board 44 and the front insulating member 22. The clearance, the left side of the front insulating member 22, passes through the through hole 33 formed in the peripheral surface, reaches the stator 19, and cools the coil 25 through the slot between the coils 25 and 25.

As described above, according to the impact driver 1 of the above embodiment, the sensor circuit board 44 through which the rotating shaft 35 penetrates in the orthogonal direction is connected to the through hole 48 of the rotating shaft 35, and the rotating shaft 35 communicates with the through hole 48 in the radial direction. And the sensor circuit board 44 can be assembled to the stator 19 in a state in which the motor 12 is accommodated in the half housing 17a, so that the bearing 40 of the rotating shaft 35 is attached to the sensor circuit board. It is not necessary to pass through the through holes 48 of the 44. Therefore, the size of the bearing 40 of the rotating shaft 35 is not restricted.
In particular, here, the positioning groove 31 for positioning the sensor circuit board 44 by sliding the sensor circuit board 44 in the direction orthogonal to the rotation shaft 35 is provided in the front insulating member 22 provided on the end face of the stator 19. Can be easily and accurately performed. Further, since the positioning groove 31 positions the sensor circuit board 44 with respect to the axial direction and the rotational direction, rattling after assembly is also suppressed.

Note that the positioning portion is not limited to the groove, and positioning may be performed with pins, ribs, and the like provided on the front insulating member as long as the sensor circuit board can be positioned in the axial direction and / or the rotational direction. The slit on the sensor circuit board side can also be appropriately changed, such as being formed with the same width as the diameter of the through-hole, or formed so that the width increases as it goes outward without being formed with the same width in the radial direction.
Moreover, in the said form, although the sensor circuit board is assembled | attached with respect to the stator, if it is the assembly | attachment after accommodating a motor, for example, it will be a sensor with respect to the positioning rib provided in the inner surface of the halved housing lowered. You may make it assemble | attach with respect to either half housings, such as assembling a circuit board.
In addition, the sensor circuit board may be provided upside down. The power tool is not limited to the impact driver, and the present invention is applicable to other tools such as a driver drill.

  1..Impact driver, 2..Main body, 3..Grip, 5..Battery pack, 9..Controller, 12..Motor, 14..Spindle, 15..Blow mechanism, 16..Anvil, 17 ..Motor housing, 17 a, 17 b ..Half housing, 19 .Stator, 20 ..Rotor, 22. .Front insulation member, 26 ..Protrusion, 27 ..Flat surface, 29. ..Front wall part 31 ..Positioning groove 32 ..Blocking part 35 ..Rotating shaft 40, 42 ..Bearing 44 ..Sensor circuit board 45 ..Rotation detecting element 46. , 47 .. connection part, 48 .. through hole, 49 .. slit, 57 .. bearing retainer, 62 .. hammer case, 80 .. hammer, 81 .. coil spring.

Claims (5)

A motor comprising a stator and a rotor having a rotating shaft;
A substrate through which the rotation axis passes in an orthogonal direction;
A first housing and a second housing for housing the motor and the substrate;
The electric tool characterized in that the substrate can be assembled to any of the stator, the first housing, and the second housing in a state where the motor is accommodated in the first housing. A motor comprising a stator and a rotor having a rotating shaft;
A substrate through which the rotation axis passes in an orthogonal direction;
A housing for housing the motor and the substrate;
The substrate has a through hole of the rotating shaft and a slit communicating with the through hole and allowing the rotating shaft to pass in a radial direction.   The electric tool according to claim 1, wherein a positioning portion capable of positioning the substrate by sliding the substrate from a direction orthogonal to the rotation shaft is provided on an insulating member provided on an end surface of the stator. A motor comprising a stator and a rotor having a rotating shaft;
A substrate through which the rotation axis passes in an orthogonal direction;
A first housing and a second housing for housing the motor and the substrate;
An electric tool characterized in that a positioning portion capable of positioning by sliding the substrate in a direction orthogonal to the rotation shaft is provided in any of the stator, the first housing, and the second housing.   The electric tool according to claim 4, wherein the positioning unit is positioning with respect to an axial direction and / or a rotational direction of the rotating shaft.

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