JP2016214041A - Electric power tool - Google Patents

Abstract

Even in a brushless motor in which coils of respective phases are delta-connected in series, advance phase control is possible without being influenced by stator magnetic flux, and motor efficiency is improved. A brushless motor used as a drive source has slots 78, 78... Between a plurality of teeth 63 projecting inward, and coils 64 are wound around the teeth 63, respectively. , The stator 9 in which the coils 64 and 64 of each phase are connected in a delta manner by series winding, the rotor 10 having a permanent magnet 68 and rotatable inside the stator 9, and fixed to the stator 9 to rotate the rotor 10. And a sensor circuit board having magnetic sensors 66, 66... For detection, and the magnetic sensor 66 is provided at a position corresponding to the approximate center of the slot 78 in the rotational direction of the rotor 10. [Selection] Figure 9

Description

  The present invention relates to an electric tool such as a driver drill using a brushless motor.

  Among power tools such as driver drills, those using a brushless motor as a drive source are known from the viewpoint of compactness and durability. In this brushless motor, as disclosed in, for example, Patent Document 1, a plurality of (for example, six) teeth are projected through slots on the inside of a stator core formed by laminating a plurality of steel plates, and each phase is provided on each tooth. And a rotor having a rotating shaft penetrating the stator and incorporating a permanent magnet, and the stator includes a magnet for detecting the position of the permanent magnet provided on the rotor. A disk-shaped sensor circuit board provided with a sensor (Hall IC or the like) is attached.

Japanese Patent Laying-Open No. 2015-56953

  In the brushless motor, the energization timing for supplying the excitation current to the coil of each phase is controlled according to the rise time (forward rotation) and fall time (reverse rotation) of the output signal of the magnetic sensor. If advance phase control is performed in which the energization timing is advanced from the rise time or fall time of the output signal of the magnetic sensor, loss can be suppressed and motor efficiency can be increased. Therefore, it is conceivable to perform phase control by shifting the position of the magnetic sensor from the center of the teeth, for example, by rotating the electrical angle by 30 ° in the direction of rotation by 30 °. If this is the case, the sensor magnetic flux detected by the magnetic sensor is affected by the stator magnetic flux, and the rotational position of the rotor may be displaced and detected.

  Therefore, the present invention provides an electric tool that can perform advance phase control without being affected by the stator magnetic flux and improve motor efficiency even in a brushless motor in which coils of each phase are connected in series and delta. It is intended to do.

In order to achieve the above object, according to the first aspect of the present invention, there is a slot between a plurality of teeth projecting inward, and a coil is wound around each tooth, and a coil of each phase is wound in series. A stator connected to the delta, a rotor having magnets and rotatable inside the stator, and a sensor circuit board having a magnetic sensor fixed to the stator and detecting the rotation of the rotor. It is provided at a position corresponding to the approximate center of the slot in the rotation direction.
In order to achieve the above object, according to a second aspect of the present invention, there is provided a slot between a plurality of inwardly projecting teeth, the coils are wound around the teeth, and the coils of each phase are connected in series to form a delta. A stator that is connected, a rotor that has a magnet and is rotatable inside the stator, and a sensor circuit board that is fixed to the stator and has a magnetic sensor that detects the rotation of the rotor. The sensor circuit board is provided at a position corresponding to the approximate center of the slot in the rotation direction, and the sensor circuit board is attached to an electrical insulating member provided on the end face of the stator.
In the present invention, “substantially the center of the slot” includes the case where it is strictly located, but it is also acceptable if the position is not affected by the stator magnetic flux and the center is slightly deviated in the rotational direction of the rotor. This is the purpose.
According to a third aspect of the present invention, in the configuration of the first or second aspect, the magnetic sensor is arranged on a circumference where the outermost peripheral portion of the outer shape of the rotor is located.
According to a fourth aspect of the present invention, in the configuration of any one of the first to third aspects, the outer shape of the rotor is non-circular.
According to a fifth aspect of the present invention, in the configuration of the fourth aspect, the magnetic sensor is arranged outside a circle where the innermost peripheral portion of the outer shape of the rotor is located.
According to a sixth aspect of the present invention, in any one of the first to fifth aspects, a recess is formed in the outer periphery of the stator on extension of the teeth.
According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the sensor circuit board is screwed to the stator at a position on the extension of the teeth.

  According to the present invention, by providing the magnetic sensor at a position corresponding to the approximate center of the slot in the rotation direction of the rotor, even in a brushless motor in which the coils of each phase are delta-connected in series, the stator magnetic flux Advance phase control can be performed without being affected, and motor efficiency can be improved.

It is a side view of a vibration driver drill. It is a rear view of a vibration driver drill. It is a longitudinal cross-sectional view of a vibration driver drill. It is an enlarged view of a main-body part. It is a perspective view of a stator. It is a top view of a stator. It is A arrow directional view of FIG. It is a B arrow view of FIG. It is a cross-sectional schematic diagram of a stator. It is an enlarged view of a fusing part. It is a schematic diagram which shows the winding method of a wire, (A) shows a connection side and (B) shows an anti-connection side, respectively. It is explanatory drawing which shows the connection state of a coil. (A) is a top view of the stator which used the heat radiating member, (B) is a side view. (A) is a bottom view of a stator using a heat dissipation member, and (B) is a side view. (A) is the sectional view on the AA line of FIG. 14, (B) is the sectional view on the BB line. (A) is a plan view of a stator using a small-diameter sensor circuit board, and (B) is a bottom view. (A) is a side view of a stator using a small-diameter sensor circuit board, and (B) is a sectional view taken along the line CC. It is a perspective view of the front insulator of the example of a change. (A) is a top view of the front insulator of the modification, (B) is a DD line sectional view, (C) is an EE line sectional view.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 is a side view of a vibration driver drill showing an example of an electric tool, FIG. 2 is a rear view, FIG. 3 is a longitudinal sectional view, and FIG. 4 is an enlarged sectional view of a main body portion. The vibration driver drill 1 has a handle 3 protruding downward from a main body 2 extending in the front-rear direction, and a drill chuck 4 is provided at the front end of the main body 2 as a tip tool holding portion capable of gripping a bit at the tip. A battery pack 5 serving as a power source is attached to the lower end of the handle 3. The housing 6 is formed by assembling left and right half housings 6a and 6b, in which the rear half of the main body 2 and the handle 3 are connected, by screws 7 in the left and right direction.

  In the main body 2, an inner rotor type brushless motor 8 including a cylindrical stator 9 and a rotor 10 disposed inside the stator 9 and having a rotating shaft 11 in the rotor 10 is accommodated in the rear part. A gear assembly 12 having a spindle 13 protruding forward from the housing 6 is assembled in front of the brushless motor 8 so that the rotation of the rotary shaft 11 can be decelerated and transmitted to the spindle 13. The drill chuck 4 is attached to the front end of the spindle 13. A switch 14 is accommodated in the upper part of the handle 3 below the main body 2, and the trigger 15 is projected forward. A forward / reverse switching button 16 of the motor is provided above the switch 14, and an LED 17 that irradiates the front of the drill chuck 4 is housed obliquely upward in front of the switch 14.

  A mounting portion 18 on which the battery pack 5 is slid from the front is formed at the lower end of the handle 3, and the mounting portion 18 includes a terminal block 19 including a terminal 19 a to which the battery pack 5 is electrically connected, A controller 20 that includes a microcomputer that controls the brushless motor 8, six switching elements, and the like and is electrically connected to the stator 9 of the brushless motor 8 is accommodated. Reference numeral 21 denotes a strap locking portion provided on the rear surface of the mounting portion 18 using a screw boss, and reference numerals 22 and 22 denote hook attachment portions for suspension. In the battery pack 5, reference numeral 23 denotes a rechargeable battery (here, 10.8V having three rechargeable batteries (cells)), 24 denotes a terminal, 25 denotes a hook for retaining, and the hook 25 is released by a button 26 on the front. Operation is possible.

The gear assembly 12 is assembled in a cylindrical first gear case 27 positioned in front of the brushless motor 8 and in front of the first gear case 27, and has a two-stage cylindrical shape having a large diameter portion 29 and a small diameter portion 30. The two gear cases 28 are formed. The first gear case 27 supports the rotary shaft 11 via a bearing 31 and projects the tip of the rotary shaft 11 to which the pinion 32 is attached into the gear assembly 12.
The gear assembly 12 accommodates a planetary gear reduction mechanism 33 in which carriers 35A to 35C supporting a plurality of planetary gears 36A to 36C revolving in the internal gears 34A to 34C are arranged in three stages in the axial direction. Thus, the pinion 32 of the rotating shaft 11 meshes with the first stage planetary gear 36A. Among these, the second-stage internal gear 34B is rotatable and can be moved back and forth in the axial direction, and can be engaged with the coupling ring 37 held in the large-diameter portion 29 at the advanced position.

  A speed switching lever 39 that is slidable back and forth on the housing 6 is connected to the internal gear 34B via a connecting member 38. When the speed switching lever 39 is slid rearward, the internal gear 34B moves backward via the connecting member 38, and meshes with the outer periphery of the first stage carrier 35A while maintaining mesh with the second stage planetary gear 36B. . Therefore, the high-speed mode in which the second-stage deceleration is cancelled. Conversely, when the speed switching lever 39 is slid forward, the internal gear 34B moves forward away from the carrier 35A via the connecting member 38, and the coupling ring 37 remains engaged with the second stage planetary gear 35B. And the rotation is restricted. Therefore, it becomes a low speed mode in which the second-stage deceleration functions.

  In this case, a vibration mechanism for applying a vibration in the axial direction to the spindle 13 is provided inside the small diameter portion 30 of the second gear case 28, and the spindle 13 with a predetermined load on the spindle 13 is provided outside the small diameter portion 30. A clutch mechanism for interrupting torque transmission to the spindle 13 is provided, and a switching operation described later causes a vibration drill mode in which the spindle 13 vibrates while rotating, a drill mode in which the spindle 13 only rotates, a torque to the spindle 13 with a predetermined load Each clutch mode (driver mode) for interrupting transmission can be selected. Hereinafter, each mechanism will be described.

In the vibration mechanism, the spindle 13 is pivotally supported by the front and rear bearings 40 and 41 in the small diameter portion 30, and the rear end thereof is splined to the third stage carrier 35C. Between the bearings 40 and 41 in the spindle 13, a ring-shaped first cam 42 and second cam 43 are coaxially covered from the front. The first cam 42 has cam teeth on the rear surface and is splined to the spindle 13. The second cam 43 has cam teeth formed on the front surface and is loosely inserted into the spindle 13 so as not to rotate within the small diameter portion 30.
Further, a plurality of steel balls 45, 45... Are held between the steel balls 45 and the first cam 42 between the bearings 40 in front of the first cam 42 by a ring-shaped receiving plate 44. The cam plate 46 is provided. The arm 47 extending rearward from the cam plate 46 is connected to a mode switching ring 48 that is rotatably assembled to the large-diameter portion 29 in front of the housing 6 via a connecting plate 49 so that the mode switching ring 48 can be rotated. Due to the rotation of the connecting plate 49, the first cam 42 is slid rearward via the cam plate 46 and meshed with the second cam 43.

  In the clutch mechanism, a clutch ring 50 is rotatably mounted on the small diameter portion 30 in front of the mode switching ring 48. Inside the clutch ring 50, a screw feed plate 51 that is screwed into a screw portion formed on the outer periphery of the small diameter portion 30 is provided so as to be able to rotate integrally with the clutch ring 50 and move in the axial direction. A front receiving plate 52 that is movable back and forth in the axial direction while being restricted by the small-diameter portion 30 is provided behind the front plate 52. A rear side of the front receiving plate 52 is provided with a pressing plate 54 that comes into contact with the front surface of the closing portion 53 between the large diameter portion 29 and the small diameter portion 30, and a rear receiving plate 55 in front thereof. Between the plate 52 and the rear receiving plate 55, a plurality of coil springs 56 are arranged at equal intervals in the circumferential direction.

  In addition, a plurality of steel balls 57, 57 are held at equal intervals in the circumferential direction behind the pressing plate 54 so as to contact the front surface of the third internal gear 34C that is rotatably provided. The clutch cam (not shown) protruding from the front surface of the internal gear 34C can be engaged in the circumferential direction. The urging force of the coil springs 56 and 56 is transmitted to the internal gear 34C via the steel ball 57, the pressing plate 54, and the rear receiving plate 55, whereby the internal gear 34C is restricted in rotation. By rotating the clutch ring 50 and screwing the screw feed plate 51 and the front receiving plate 52 in the axial direction to change the axial length of the coil spring 56, the pressing force to the internal gear 34C can be changed.

Next, each operation mode will be described. First, at the first rotation position of the mode switching ring 48 in which the cam plate 46 does not slide the first cam 42 backward, the first cam 42 is in front of the second cam 43 and meshes with the second cam 43. do not do. Therefore, the clutch mode is set in which the pressing force applied to the internal gear 34C can be changed by rotating the clutch ring 50.
When the brushless motor 8 is driven by pushing the trigger 15 in this clutch mode, the rotating shaft 11 rotates, the spindle 13 rotates via the planetary gear speed reduction mechanism 33, and a screw with a driver bit attached to the drill chuck 4. Tightening can be performed. When the screw tightening progresses and the load on the spindle 13 exceeds the pressing force of the coil spring 56 that fixes the internal gear 34C, the clutch cam of the internal gear 34C moves the steel ball 57, the pressing plate 54, and the rear receiving plate 55 forward. And the internal gear 34C is idled to complete the screw tightening (clutch operation).

Next, at the second rotational position where the mode switching ring 48 is rotated by a predetermined angle from the clutch mode, the regulating ring 58 provided on the mode switching ring 48 engages with the rear receiving plate 55 to advance the rear receiving plate 55. regulate. Therefore, a drill mode in which the forward movement of the pressing plate 54 is always restricted regardless of the pressing force of the coil spring 56 is set.
When the spindle 13 is rotated in this drill mode, the steel ball 57 does not get over the clutch cam of the internal gear 34C regardless of the load on the spindle 13, so that the fixed state of the internal gear 34C does not change. The rotation of 13 continues. At this time, since the first cam 42 does not slide backward, the spindle 13 does not vibrate.

The cam plate 46 slides the first cam 42 rearward at a third rotational position where the mode switching ring 48 is further rotated by a predetermined angle from the drill mode. On the other hand, the engagement between the regulating ring 58 and the rear receiving plate 55 does not change. Therefore, it becomes a vibration mode in which the first cam 42 and the second cam 43 mesh.
When the spindle 13 is rotated in this vibration mode, the first cam 42 that rotates integrally with the spindle 13 meshes with the second cam 43 that is fixed in the small-diameter portion 30, so that vibration is generated in the spindle 13. In addition, since the fixing state of the pressing plate 54 by the restriction ring 58 does not change, the rotation of the spindle 13 continues regardless of the load on the spindle 13.

The stator 9 of the three-phase brushless motor 8 is held around the front-rear direction by ribs 59, 59 formed on the inner surfaces of the half housings 6a, 6b. The stator 9 includes six ring-shaped front insulators 61 and rear insulators 62, which are electrical insulating members, assembled on the front and rear end faces of a stator core 60 formed by laminating a plurality of steel plates, and projecting from the stator core 60. Coils 64, 64,... Are wound around the teeth 63, 63,..., And a magnetic sensor 66 such as a Hall IC that detects the position of the permanent magnet 68 provided on the rotor 10 is provided on the front surface of the front insulator 61. , 66... Are mounted with screws.
A temperature detection element is arranged on the sensor circuit board 65, and the temperature detection signal is input to the controller 20, and the controller 20 that monitors the signal stops the control of the brushless motor 8 at a predetermined temperature. Also good. This makes it possible to effectively suppress the temperature rise of the brushless motor 8 of the 10.8 V vibration driver drill 1 that tends to cause a temperature rise.

The rotor 10 is arranged around the rotating shaft 11 and has a substantially cylindrical rotor core 67 formed by laminating a plurality of steel plates, and four plate-like permanent magnets (sintered magnets) 68 fixed inside the rotor core 67. , 68... The permanent magnets 68 are inserted into through holes formed so as to be located on four sides of a square centering on the rotation shaft 11 in the cross section of the rotor core 67 and fixed by an adhesive and / or press-fitting.
The rear end of the rotating shaft 11 is pivotally supported by a bearing 69 held at the rear portion of the housing 6, and a centrifugal fan 70 is attached to a front portion of the bearing 69. 71 are exhaust ports formed on the left and right side surfaces of the housing 6 at the position of the centrifugal fan 70, and air intake ports 72, 72 are provided on the side surfaces of the housing 6 that contact the outside of the stator 9. 1).

  Further, a rear stopper 73 is provided between the rotor core 67 and the centrifugal fan 70. The stopper 73 is a disc made of brass and having the same outer diameter as the rotor core 67, and is fixed to the rotary shaft 11 coaxially with the rotor core 67. On the other hand, a front stopper 74 is provided on the inner side of the sensor circuit board 65 between the rotor core 67 and the front bearing 31. The front stopper 74 is a disc made of brass and having an outer diameter smaller than that of the rotor core 67. The front stopper 74 is coaxial with the rotor core 67 and is fixed to the rotary shaft 11 with a gap between the rotor core 67 and the front stopper 74. However, the outer diameter of the front stopper 74 is larger than the inner circle surrounded by the four permanent magnets 68, 68... So that the front stopper 74 is positioned in front of each permanent magnet 68. .

Here, the structure of the stator 9 will be described in detail with reference to FIGS. However, in the single stator 9 shown in FIGS. 5 to 8, the front insulator 61 side is described as the upper side and the rear insulator 62 side is described as the lower side.
On the outer periphery of the stator core 60, six recesses 75 are formed at equal intervals in the circumferential direction on the extension of the teeth 63, and the front insulator 61 is formed at the end of each groove 75. And the rear insulator 62 are fitted (press-fitted) with fitting pieces 76, 76... Integrally formed in the axial direction. By press-fitting the fitting piece 76, the stator core 60 and the front and rear insulators 61 and 62 can be firmly integrated against each other by resisting distortion of the front and rear insulators 61 and 62.
Further, a locking recess 77 for locking a projection (not shown) provided on the inner surface of the housing 6 is provided on the side surface of the front insulator 61 so that the stator 9 can be prevented from rotating and positioned in the front-rear direction.

  In the front insulator 61, among the six slots 78, 78,... Formed between the teeth 63, 63,. Holding portions 82, 82,... Of a fusing terminal 81 for fusing the wires 79 of the coils 64, 64 and the power supply lines 80 of the respective phases are provided so as to protrude upward. The holding portion 82 has a pair of protrusions 83, 83 each having a U-shape in plan view, arranged in the circumferential direction of the front insulator 61 in a direction facing each other, and above the ring-shaped upper end surface 61a of the front insulator 61. A hook 84 having an L-shape in a side view for holding the power supply line 80 is provided outside the teeth 63 between the three holding portions 82, 82. Has been. Two of the three power lines 80 are bundled by the tape 109 at a position near the stator 9.

Further, on the outside of one tooth 63 located between the holding portions 82, 82 and on the outside of two teeth 63, 63 located one circumferentially from the tooth 63 (the vertex position of the regular triangle) The three screw bosses 85, 85,... For screwing the sensor circuit board 65 are protruded at a height that is lower than the holding portion 82 and protrudes upward from the upper end surface 61a of the front insulator 61. Yes. A stage having a receiving surface 87 having the same height as the screw boss 85 on the outside of the teeth 63, 63 positioned between the screw bosses 85, 85 and bosses 88A, 88B protruding upward from the receiving surface 87. The attached bosses 86A and 86B are projected. The boss 88A of the stepped boss 86A is disposed on a concentric circle slightly smaller than the concentric circle of the screw boss 85, and the boss 88B has a smaller diameter than the boss 88A.
In the rear insulator 62, circumferential guide ribs 89, 89... Stand concentrically outside the slots 78.

  The sensor circuit board 65 radiates between the notches 91 and 91 by forming six notches 91 that are curved toward the through hole 90 of the rotating shaft 11 provided at the center at equal intervals in the circumferential direction. .. Are formed at equal intervals in the circumferential direction, and each notch portion 91 extends over the inner circumference of the stator core 60 and overlaps each slot 78 in plan view. It is curved until. The tip of the fixed piece 92 slightly exceeds the outer periphery of the stator core 60, and two of the adjacent fixed pieces 92 (hereinafter referred to as 92A and 92B when distinguished) are the other four. It is longer than the two fixed pieces 92.

Of the six fixing pieces 92, three fixing pieces 92, 92,... Positioned at the apex of an equilateral triangle including one long fixing piece 92B are respectively connected to screw bosses 85 positioned on the extensions of the teeth 63 by screws 93. The bosses 88A and 88B of the stepped bosses 86A and 86B are inserted into the fixed pieces 92 between the fixed pieces 92 and 92 that are fixed and screwed, respectively. A connection portion 94 for six lead wires 95A, 95A,... For outputting detection signals of the three magnetic sensors 66 is provided on the upper surface of the remaining one fixed piece 92A. A connector 96A is provided at the tip of the lead wire 95A, and the lead wires 95A and 95B are connected to each other by coupling with a connector 96B provided on the lead wire 95B drawn from the controller 20.
The three magnetic sensors 66 are arranged at predetermined intervals around the through-hole 90 on the lower surface of the sensor circuit board 65. Here, as shown in FIG. On the circumference of the circle C1 where the outermost peripheral portion of the rotor 10 is non-circular (outside the circle C2 where the innermost peripheral portion is located in the outer shape of the rotor 10), and the center of the slot 78 (teeth) The phase is shifted 30 ° from the center line of 63).

In FIG. 9, the stator outer diameter S1 is φ38 (unit mm, hereinafter the same), the stator inner diameter S2 is φ21, the teeth width S3 is 4.0, the back yoke width S4 is 2.0, the slot opening width S5 is 4.5, The rotor outer diameter S6 is φ20.
The stator inner diameter S2 is in the range of φ20 to φ22 (ratio 0.53 to 0.58 when the stator outer diameter is 1), and the teeth width S3 is in the range of 4.0 to 4.4 (same ratio of 0.2). 11 to 0.12), the back yoke width S4 is 2.0 to 2.2 (same ratio 0.05 to 0.06), and the slot opening width S5 is 2.5 to 4.5 (same ratio 0.07 to 0.07). 0.12), the rotor outer diameter S6 can be changed in the range of φ19 to φ21 (same ratio of 0.50 to 0.55). In this way, if the magnetic path is designed based on the stator outer diameter in the IPM rotor, the output density can be increased, and even if the battery voltage is 10.8 V or the stator outer diameter is 40 mm or less, the rotation of the rotor The number can be a high rotation of 24,000 rpm or more. However, if the battery voltage is 14.4V, 18V, or 36V, high rotation of 30000 rpm to 40000 rpm is also possible.

  The fusing terminal 81 is formed by folding a band-shaped metal plate in half, forming L-shaped blade pieces 98 and 98 on both sides of one plate portion 97A, and folding the tip of the other plate portion 97B outward. Then, by inserting the blade pieces 98 and 98 into the projections 83 and 83 of the holding portion 82 from above with the folded portion down, the plate portion 97B is positioned on the outside as shown in FIG. It is held in an open posture. Here, a curled portion 99 in which the power line 80 is accommodated is formed inside the folded portion, and a bent portion 100 in which the wire 79 of the coil 64 is sandwiched is formed on the plate portion 97B on the upper side. Reference numeral 100a denotes a folded portion of the plate portion 97B. Thus, the fusing terminals 81 are gathered and arranged on the half circumference side of the stator 9 in plan view by the holding portion 82.

The power supply line 80 peels only the portion of the stranded wire 80b that is fused to the fusing terminal 81, leaving the tip 80a of the insulation coating. By leaving the tip 80a in this way, the stranded wire 80b is not separated. In addition to leaving the tip of the insulation coating, the twisted wire breakage preventing means can be covered with a heat-shrinkable tube to cover the tip of the stranded wire 80b, caulking the tip with a splice terminal, solder, welding, thermosetting This can also be achieved by hardening the tip with resin.
Further, a giboshi terminal 101 is provided at the tip of the power supply line 80 drawn from the stator 9, and the power supply lines are connected to each other by coupling with a not-shown power supply line drawn from the controller 20. It has become.

  The six coils 64, 64... Here are formed by winding one wire 79 around each tooth 63 in order, and the coils 64, 64 for one phase are respectively connected to the fusing terminal 81. The connecting wire 102 connecting the coils 64, 64 for one phase located diagonally is wired not on the front insulator 61 side but on the rear insulator 62 side. Hereinafter, the winding method of the coil 64 will be described. When it is necessary to distinguish between the three phases U, V, and W, U, V, and W are added to the reference numerals of the components, and the pairs of the phases are paired. When distinguishing the teeth 63 and the coils 64, the numerals 63U1, 63U2, 64U1, 64U2 and the like are further given for explanation.

FIG. 11 is a schematic diagram showing a winding method, in which (A) is the connection side (front insulator 61 side), and (B) is the anti-connection side (rear insulator 62 side). 81U, 81V and 81W are fusing terminals. Symbols with a + character in the circle are wound to the back side perpendicular to the paper surface, and symbols with a black circle inside the circle are wound to the near side perpendicular to the paper surface. Each wire is shown. Further, in the connection side and the anti-connection side, the description will be made assuming that the counterclockwise direction is left and the clockwise direction is right.
First, on the connection side, the starting end 79a of the wire 79 is temporarily fixed to the fusing terminal 81U to which the U-phase power supply line 80U is temporarily fixed, and the coil 64U1 is formed by winding the teeth 63U1 on the left side from the right side. Pull out to the left side of the teeth 63U1 on the opposite side, draw the crossover wire 102U indicated by the solid arrow on the outside of the guide rib 89 in a clockwise direction by approximately half a circumference, and then wind the coil 64U2 around the diagonal teeth 63U2 from the right side. Form. Then, the wire 79 is pulled out from the left side of the tooth 63U2 on the connection side, and temporarily fixed to the fusing terminal 81W to which the W-phase power supply line 80W is temporarily fixed.

  Next, the coil 64W1 is formed by winding the tooth 63W1 adjacent to the left side of the fusing terminal 81W from the right side, and then the coil 64W1 is drawn to the left side of the tooth 63W1 on the non-connection side, and the connecting wire 102W indicated by the dotted line outside the guide rib 89 Is wound clockwise by approximately a half turn, and then wound around a diagonal tooth 63W2 from the right side to form a coil 64W2. Then, after pulling out to the left side of the teeth 63W2 on the same anti-connection side and drawing the crossover wire 102W clockwise by about a half turn outside the guide rib 89, pulling it out to the left side of the diagonal teeth 63W1 on the connection side, the V phase The power line 80V is temporarily fixed to the temporarily fixed fusing terminal 81V. In other words, the wires 79 forming the W-phase coils 64W1 and 64W2 are wired between the teeth 63W1 and 63W2 on the rear insulator 62 side in a clockwise direction by approximately a half turn.

Next, a coil 64V1 is formed by winding the tooth 63V1 adjacent to the left side of the fusing terminal 81V from the right side, and then the coil 64V1 is drawn out to the left side of the tooth 63V1 on the reverse connection side. After winding 102V clockwise by about a half turn, the coil 64V2 is formed by winding it around the diagonal teeth 63V2 from the right side. Then, after pulling out to the left side of the teeth 63V2 on the same anti-connection side and drawing the crossover wire 102V clockwise by about a half turn on the outside of the guide rib 89, pulling it out to the left side of the diagonal teeth 63V1 on the connection side, The terminal end 79b is temporarily fixed to the adjacent fusing terminal 81U. That is, the wires 79 forming the V-phase coils 64V1 and 64V2 are also routed between the teeth 63V1 and 63V2 counterclockwise on the rear insulator 62 side by approximately a half turn. Actually, as shown in FIGS. 7 and 8, the crossover wires 102 are wired so as to overlap in the axial direction outside the guide rib 89.
Finally, by fusing the power supply line 80 and the wire 79 at each fusing terminal 81, as shown in FIG. 12, the stator 9 in which the coils 64 and 64 of each phase wound in series are delta-connected is obtained.

  In the stator 9 in which the connection is completed and the sensor circuit board 65 is attached, the sensor circuit board 65 is located above the upper end surface 61a of the front insulator 61 by the upper surface of the screw boss 85 and the receiving surfaces 87 of the stepped bosses 86A and 86B. It is supported at a position orthogonal to the axis of the stator 9. At this time, the tips of the hooks 84 also come into contact with the lower surfaces of the long fixed pieces 92A and 92B to support the fixed pieces 92A and 92B. Here, since the connecting wire 102 between the coils 64 of each phase is wired on the anti-connection side, a sufficient gap is formed between the front insulator 61 and the sensor circuit board 65. Further, in the fixed state of the sensor circuit board 65, each holding part 82 and the fusing terminal 81 pass through the notch part 91 of the sensor circuit board 65 and protrude upward from the sensor circuit board 65, and each tooth 63, The slot 78 between the 63 is exposed in the notch 91 of the sensor circuit board 65 (FIG. 6).

Here, since the power supply line 80 is held by the hook 84 and the fixed piece 92, the power supply line 80 becomes difficult to move and also serves as a guide for wiring. Further, since the fixed piece 92A to which the lead wire 95A of the magnetic sensor 66 is connected is supported by the hook 84, the lead wire 95A is difficult to be disconnected. Furthermore, since the radial distance from the axis of the brushless motor 8 to the center of the boss 88A is smaller than the radial distance from the axis to the center of the screw 93, vibration of the sensor circuit board 65 is reduced.
Further, since the sensor circuit board 65 is attached by the screw 93, even if one of the sensor circuit board 65 and the stator 9 breaks down, it becomes possible to individually repair the sensor circuit board 65 by removing the sensor circuit board 65.

  The stator 9 is incorporated in the housing 6 in a phase where the fusing terminals 81, 81... Are located on the lower half side of the stator 9. Thereby, the power line 80 of each phase connected to the fusing terminal 81 is wired to the controller 20 side at the shortest distance without passing through the left and right outer sides of the stator 9. Therefore, the housing 6 does not increase in the radial direction, the compactness can be maintained, and the wiring length can be shortened. Further, since the power supply line 80 and the lead wire 95A of the magnetic sensor 66 can be separated from the controller 20 side by the connector 96A or the giboshi terminal 101, the stator 9 and the controller 20 can be individually repaired or replaced, and the cost can be reduced. . It should be noted that other terminals and connectors can be used for connecting the lead wires and the power wires.

In the vibration driver drill 1 configured as described above, when the trigger 15 is pushed in and the switch 14 is turned on, the microcomputer of the controller 20 outputs the permanent magnet of the rotor 10 output from the magnetic sensor 66 of the sensor circuit board 65. The rotation detection signal indicating the position 68 is obtained, the rotation state of the rotor 10 is acquired, the ON / OFF of each switching element is controlled according to the acquired rotation state, and the coils 64 and 64 of each phase of the stator 9 are controlled. The rotor 10 is rotated by passing an exciting current in order. Therefore, since the rotating shaft 11 rotates and the spindle 13 is rotated via the planetary gear reduction mechanism 33, the operation in the operation mode selected by the tip tool held by the drill chuck 4 is possible.
Here, since the magnetic sensor 66 is arranged at the center of the slot 78 of the stator 9, the energization timing for supplying the excitation current from the controller 20 to the coil 64 of each phase is advanced in both the forward and reverse rotation directions. Advance phase control that is advanced by 30 ° can be executed. The arrangement of the magnetic sensor 66 makes it difficult for the sensor magnetic flux to be affected by the stator magnetic flux, so that the sensing accuracy of the rotor 10 does not decrease.

When the centrifugal fan 70 rotates along with the rotation of the rotating shaft 11, the outside air is sucked from the intake port 72 on the side surface of the housing 6, passes through the outside and inside of the stator 9 (between the rotor 10), and is discharged from the exhaust port 71. As a result, the brushless motor 8 is cooled. At this time, in the stator 9, the slot 78 is exposed in front view by the cutout portion 91 of the sensor circuit board 65 and the crossover wire 102 is not wired between the sensor circuit board 65 and the front insulator 61. 9 can smoothly pass through the slots 78 on both sides of each coil 64 without being obstructed by the sensor circuit board 65. Therefore, each coil 64 is also effectively cooled. Further, since each fusing terminal 81 is located between the fixed pieces 92, each fusing terminal 81 is also effectively cooled by the air passing through the notch 91.
On the other hand, since the front stopper 74 and the rear stopper 73 are provided at the front and rear in the rotor 10, the movement of each permanent magnet 68 in the front and rear direction is restricted, and the falling off from the rotor core 67 is effectively prevented.

Thus, according to the vibration driver drill 1 of the said form, the coils 64 and 64 of each phase were connected in series by providing the magnetic sensor 66 in the position corresponding to the center of the slot 78 in the rotation direction of the rotor 10. Even in the case of the brushless motor 8 that is delta-connected, the advance phase control of the advance angle of 30 ° can be performed without being influenced by the stator magnetic flux and without performing the advance angle control on the software. Therefore, the motor efficiency can be improved.
Further, since the sensor circuit board 65 is attached to the front insulator 61 provided on the end face of the stator 9, the sensor circuit board 65 can be easily attached to an appropriate position using the front insulator 61.

  In the above embodiment, the magnetic sensor 66 is arranged at the center of the slot 78 so as to obtain an advance angle of 30 °. However, it is not strictly necessary to be at the center of the slot 78, and for example, the advance angle 25 in the forward rotation direction. You may make it shift | deviate from some centers, such as setting it as (degree). However, in this case, it is necessary to perform correction control on software so that the controller 20 has an advance angle of 25 ° in the reverse rotation direction. Further, the magnetic sensor 66 can be disposed on the surface opposite to the stator 9, and the coil 64 may be a delta-connected parallel winding.

  On the other hand, if the rotational speed of the rotor 10 is 24000 rpm or more as described above, the amount of current supplied to the coil 64 increases and the temperature rises. As this heat radiating member, a metal heat radiating ring having an inner diameter larger than the area where the magnetic sensor 66 is disposed between the sensor circuit board 65 and each coil 64, as in the stator 9A shown in FIGS. 103 and adopting a structure in which the heat dissipation ring 103 is bonded to the upper end surface of each coil 64 by an adhesive having thermal conductivity and insulation. 103a, 103a,... Are through holes provided in the heat dissipation ring 103 at the positions of the slots 78. The through holes 103a ensure the flow of air passing through the slots 78 and contact the heat dissipation ring 103 with air. The area is increased to improve the heat dissipation effect.

Thus, if the heat dissipation ring 103 that indirectly contacts the coil 64 is provided, the temperature rise of the coil 64 can be suppressed even when the rotor 10 is rotated at a high speed.
In addition, this heat dissipation member is not ring-shaped, but a plurality of arc-shaped members straddling a plurality of coils are provided, each coil is provided individually avoiding slots, fins are erected on the surface, or uneven It is also possible to further increase the surface area by providing. You may provide in the rear side instead of the front side of a stator.

  Further, the sensor circuit board does not need to be approximately the same size as the front insulator, and is a ring-shaped sensor circuit board 65A whose outer diameter is reduced to the inside of the coil 64 as in the stator 9B shown in FIGS. You can also. The front insulator 61 has a root portion 105 that protrudes axially along the front surface of each tooth 63 and covers the front surface of the tooth 63, and extends from the tip of the root portion 105 in the circumferential direction and upward to the inside of the coil 64. Insulating teeth 104, 104,... Each including a stopper portion 106 for preventing the tilting of the stopper portion 106 are projected, and at the lower end of the inner periphery of each stopper portion 106, a tongue-shaped inner portion 107 that receives the outer periphery of the sensor circuit board 65A. Are projected. Therefore, the sensor circuit board 65A is fixed by press-fitting, bonding with an adhesive, screwing, or the like in a state where the outer periphery is brought into contact with the inner portion 107 so as to be fitted inside each stopper portion 106. be able to. In this case as well, the magnetic sensor 66 may be disposed at substantially the center of the slot 78. However, the lead wire is drawn out from the upper side or the lower side of the sensor circuit board 65A to the outside through the slot 78 and wired in the same direction as the power line 80. do it.

As described above, the sensor circuit board 65A having a smaller diameter than that of the front insulator 61 is arranged on the inner side of the coil 64, so that the detection accuracy of the magnetic sensor 66 is improved, and the axial length and the radial dimension of the brushless motor 8 are reduced. Can be expected to be compact.
The inner portion does not need to be provided in all the stopper portions. If the sensor circuit board can be fixed, for example, it can be provided in every other stopper portion, and the shape can be changed as appropriate.
13 and 17, the front insulator 61 is provided with the sensor circuit boards 65, 65 </ b> A, but the rear insulator 62 is provided with the sensor circuit boards 65, 65 </ b> A so that the crossover wire 102 is connected to the front insulator 61. It is also possible to wire on the side.

  The form of the front insulator can also be changed as shown in FIGS. In the shape like the front insulator 61 described above, the stopper portion 106 of the insulating tooth 104 may be deformed inward by the stress generated when the coil 64 is wound, and may interfere with the rotor 10. Therefore, in the front insulator 61A, the stopper portion 106 of each insulating tooth 104 is formed with a concave portion 108 so that the central portion of the projecting side end surface is passed in the axial direction, and the stopper portion 106 is in the center when viewed in the axial direction. The stopper portion 106 is reinforced with a U-shape in which both front and rear ends in the rotor rotation direction protrude inward (axial center side) from the portion.

As described above, according to the vibration driver drill 1 of the above-described form, the front insulator 61 of the stator 9 is provided with the reinforcing means for reinforcing the stopper portion 106, so that the strength of the stopper portion 106 is increased and the stress during coil winding is increased. This reduces the possibility of deformation inward. Moreover, even if it is deformed, since the distance from the rotor 10 is secured by the recess 108, it is difficult to interfere with the rotor 10.
In particular, as the reinforcing means, the stopper portion 106 is formed in a U shape with both ends projecting inward, so that the reinforcement can be easily performed.
The reinforcing means may be configured such that the base portion 105 extending along the teeth 63 is thick in the axial direction of the stator 9 in addition to forming the stopper portion 106 in a U shape. In this case, in addition to the same wall thickness in the radial direction, the wall thickness can be gradually or gradually increased toward the center. Of course, a combination with a U-shape is also possible.

Further, here, the stator core 60 having six slots 78, and the rear insulator 62 fixed to the stator core 60 and holding a plurality of crossover wires 102, 102,... And a stator 9 having a guide rib 89 for guiding the crossover wire 102 in the direction opposite to the winding direction of the coil 64, the rotor 10 disposed inside the stator 9, and the drill chuck 4 driven by the rotor 10. , The crossover 102 can be wired by the guide ribs 89 without rattling.
Further, since the coil 64 is wound around the teeth 63 from one side of the stator core 60 in the circumferential direction and is wound on the other side, the coil 64 and the crossover wire 102 can be smoothly connected. .

In the above embodiment, the protrusion provided on the inner surface of the housing is locked to the locking recess provided on the side surface of the front insulator to prevent the rotation of the stator and the positioning in the front-rear direction. Alternatively, in addition to this, the protrusions may be provided on the outer surface of the stator core, and the protrusions may be engaged with the recesses provided on the inner surface of the housing, so that the stator is prevented from rotating and positioned in the front-rear direction.
Furthermore, the lead wire of the magnetic sensor is not limited to the case where it is connected on the extension of the teeth in the radial direction of the stator, but can be connected on the extension of the slot.
In addition, the magnetic sensor can be disposed at a position overlapping the tip of the tooth in the axial direction (outside the position in FIG. 9).
And in the said form, although only the magnetic sensor is mounted in the sensor circuit board | substrate, you may provide the switching element which forms an inverter circuit. In this case, the switching element can be arranged at either the position that overlaps the magnetic sensor in the axial direction or the position that does not overlap.

  In addition, the present invention is not limited to the vibration driver drill, and the present invention can be applied to other models such as an impact driver and a grinder as long as a brushless motor is used as a drive source. The position and orientation of the motor in the housing can be changed as appropriate. In the above embodiment, the coil is formed by a single wire (winding), but it is also possible to form the coil by a plurality of windings such as two or three. The brushless motor can also increase or decrease the number of poles and slots, and the present invention can be adopted even if the magnet is curved along the rotation direction or the SPM system in which the magnet is incorporated on the surface of the rotor.

And here the following invention can be grasped.
(1) An electric tool in which the rotation speed of a brushless motor serving as a drive source is 30000 rpm to 40000 rpm.
(2) A power tool having a battery voltage as a power source of 10.8 V and a motor rotation speed of 24000 rpm or more.
(3) A power tool having an outer diameter of a stator of a brushless motor as a driving source of 40 mm or less and a rotational speed of 24000 rpm or more.
(4) a stator core;
An electrically insulating member (the front insulators 61 and 61A in the above embodiment) fixed to the stator core;
A coil wound around the stator core via the electrical insulating member,
The electrical insulating member has a protruding portion (in the above embodiment, a stopper portion 106) disposed inside the coil,
An electric tool in which a sensor circuit board is screwed to the protrusion.
(5) a stator core;
An electrical insulating member (front insulator) fixed to the stator core;
A coil wound around the stator core via the electrical insulating member,
The electrical insulating member has a protruding portion disposed inside the coil,
A power tool in which a sensor circuit board is disposed inside the protrusion.
(6) a stator core;
An electrically insulating member (front and rear insulator) fixed to the stator core;
A coil wound around the stator core via the electrical insulating member,
The electrical insulating member has a protruding portion disposed inside the coil,
An electric tool in which an electric material component is disposed inside the protruding portion.
In addition to the sensor circuit board, there may be a crossover wire, a fusing terminal, a lead wire, a switching terminal, a short-circuit member, a capacitor, a temperature sensor, and the like. You can also.
In addition, the invention other than the invention in which the magnetic sensor is arranged at substantially the center of the slot can be applied to a Y-connected stator.

  1 .... Vibration driver drill 2 .... Main body 3 .... Handle 4 .... Drill chuck 5 ... Battery pack 6 ... Housing 8 ... Brushless motor 9,9A, 9B ... Stator 10 ..Rotor, 11 ..Rotating shaft, 12 ..Gear assembly, 13 ..Spindle, 20 ..Controller, 33 ..Planet gear reduction mechanism, 60 ..Stator core, 61, 61A ..Front insulator, 62. Rear insulator, 63 ... Teeth, 64 ... Coil, 65, 65A ... Sensor circuit board, 66 ... Magnetic sensor, 67 ... Rotor core, 68 ... Permanent magnet, 70 ... Centrifugal fan, 71 ... Exhaust port ..72..Inlet, 75..Groove, 76..Fitting piece, 78..Slot, 79..Wire, 80..Power line, 81..Fusing terminal, 82 .. Holding part, 89 ... Guide rib, 95A, 95B ... Lead wire, 96A, 96B ... Connector, 101 ... Giboshi terminal, 103 ... Heat dissipation ring, 104 ... Insulating teeth, 105 ... Base part, 106 ... -Stopper part, 107 ... Inside part, 108 ... Concave part.

Claims (7)

A stator having a slot between a plurality of teeth projecting inward, each of the teeth being wound with a coil, and the coils of each phase being delta-connected in series winding;
A rotor having a magnet and rotatable within the stator;
A sensor circuit board having a magnetic sensor fixed to the stator and detecting the rotation of the rotor,
The power tool, wherein the magnetic sensor is provided at a position corresponding to a substantially center of the slot in the rotation direction of the rotor. A stator having a slot between a plurality of teeth projecting inward, each of which is wound with a coil, and the coils of each phase are delta-connected in series;
A rotor having a magnet and rotatable within the stator;
A sensor circuit board having a magnetic sensor fixed to the stator and detecting the rotation of the rotor,
The magnetic tool is provided at a position corresponding to the approximate center of the slot in the rotation direction of the rotor, and the sensor circuit board is attached to an electrical insulating member provided on an end surface of the stator. .   The electric tool according to claim 1, wherein the magnetic sensor is disposed on a circumference where an outermost peripheral portion of the outer shape of the rotor is located.   The electric tool according to claim 1, wherein the outer shape of the rotor is non-circular.   The power tool according to claim 4, wherein the magnetic sensor is disposed outside a circle where an innermost peripheral portion of the outer shape of the rotor is located.   The electric tool according to claim 1, wherein a recess is formed on an outer periphery of the stator in an extension of the teeth.   The electric power tool according to any one of claims 1 to 6, wherein the sensor circuit board is screwed to the stator at a position on an extension of the teeth.

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