JP6095529B2 - Electric tool - Google Patents

Description

  The present invention relates to an electric tool in which a motor is accommodated in a housing.

  As shown in Patent Document 1, the electric power tool is configured such that the rear of a motor housing that houses a motor is closed by a rear cover, and a rotary shaft of the motor is supported by a bearing provided on the rear cover.

JP 2007-295773 A

Accordingly, an object of the present invention is to provide an electric tool that can effectively prevent the rear cover from rotating even if the motor housing is closed by the rear cover .

In order to achieve the above object, an invention according to claim 1 is an electric tool, which is a motor including a stator and a rotor, a tip tool driven by the motor, and a cylindrical motor in which the motor is accommodated. A housing and a cap-shaped rear cover that closes the rear end of the motor housing. The rear cover holds a bearing that supports the rear end of the rotating shaft of the rotor and is coupled to the motor housing by screws from the rear. In addition, at least a portion of the rear cover is covered with an elastomer covering portion , and a screw boss into which the screw is screwed is projected rearward of the rear end surface of the motor housing. It is characterized by being fitted to .
According to a second aspect of the present invention, in the configuration of the first aspect, the covering portion is also formed on a radially outer side of a portion where the screw boss is fitted .
According to a third aspect of the present invention, in the configuration of the first or second aspect, a concave portion is formed at one of the coupling end portions of the motor housing and the rear cover, and a convex portion that fits into the concave portion is formed at the other. It is characterized by that.
According to a fourth aspect of the present invention, in the configuration of any one of the first to third aspects, a flat surface in the left-right direction is formed on the lower surface of the rear cover, and the motor housing is a flat surface that receives the flat surface of the rear cover. It is characterized in that a simple receiving surface is formed .
According to a fifth aspect of the present invention, in the configuration according to any one of the first to fourth aspects, a covering portion is also formed on the outer surface of the motor housing, and the covering portion of the rear cover and the covering portion of the motor housing are continuous. It is characterized by being connected.
According to a sixth aspect of the present invention, in the configuration of the fifth aspect, at least a covering portion of the motor housing is provided with a contact portion that partially contacts the flat surface when placed on the flat surface in a horizontal direction. It is what.

  According to the present invention, even if the motor housing is closed by the rear cover, the baffle function can be easily obtained while maintaining compactness.

It is a general view of an impact driver. It is a longitudinal cross-sectional view of an impact driver. It is an expanded sectional view of a main part. It is an AA line expanded sectional view. It is a BB sectional view. It is CC sectional view taken on the line. It is an external view of an impact driver, (A) shows a side, (B) shows a front, (C) shows a back, and (D) shows a plane, respectively. It is an expanded sectional view of the main part rear part which shows the example of a change of a baffle part. It is an expanded sectional view of the main part rear part showing the omission example of a baffle part.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an overall view of an impact driver which is an example of an electric tool, FIG. 2 is a longitudinal sectional view, and the impact driver 1 has a main body with a central axis in the front-rear direction (the right side in FIG. 2 is the front). 2 and a grip portion 3 projecting downward from the main body portion 2, and a battery pack 5 serving as a power source is attached to an attachment portion 4 provided at the lower end of the grip portion 3. 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 controller 9 are provided in the attachment part 4. In addition, a push button 11 for operating the number of revolutions and a switch panel 10 for displaying the remaining battery capacity are provided.

  3 is an enlarged cross-sectional view of the main body 2, and FIG. 4 is an enlarged cross-sectional view along the line AA. The main body 2 has a motor 12, a planetary gear speed reduction mechanism 13, a spindle 14, and a striking mechanism 15 in this order from the rear. The anvil 16 is housed and protrudes forward from the front end of the main body 2. Note that the rear half of the main body 2 has a cylindrical motor housing 17 that houses the motor 12 and is integrated with the grip 3, and the motor housing 17 and the grip 3 are a pair of left and right halves. The split housings 17a, 17b are formed by assembling 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, the stator 19 is wound around the stator core 21 via the stator core 21, the front insulating member 22 and the rear insulating member 23 provided before and after the stator core 21, and the front insulating member 22 and the rear insulating member 23. A plurality of coils 24, 24,... Rotated. In addition, the rotor 20 is disposed on the outer side of the rotating shaft 25 positioned at the shaft center, the cylindrical rotor core 26 disposed around the rotating shaft 25, and the outer surface of the rotor core 26. The permanent magnets 27, 27,... With alternating polarities, and a plurality of sensor permanent magnets 28, 28,. At the front end of the front insulating member 22, a sensor circuit board 29 mounted with three rotation detection elements (not shown) for detecting the position of the sensor permanent magnet 28 of the rotor 20 and outputting a rotation detection signal is provided by screws 30. It is fixed. The terminal of the coil 24 is electrically connected to the sensor circuit board 29 in a penetrating state.

  The switching element for switching the coil 24 is mounted on the controller 9, and a lead wire 29 a such as a signal line connected from the controller 9 to the sensor circuit board 29 is drawn backward from the lower end of the sensor circuit board 29. However, the screw 18a 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 29a. In this way, the stator 19 of the motor 12 can be firmly held by the screw 18a located on the lower rear side of the motor housing 17.

  The stator 19 is held coaxially with the main body 2 by ribs 31 protruding from the inner surface of the motor housing 17. On the rear surface of the motor housing 17, a cap-shaped rear cover 32 is attached from behind to screws bosses 17 e and 17 e formed on the half housings 17 a and 17 b by screws 33 and 33, and is held by the rear cover 32. The bearing 34 thus supported supports the rear end of the rotary shaft 25. With the screws 33, 33, the half housings 17a, 17b and the rear cover 32 can be firmly integrated, and the left and right separation of the half housings 17a, 17b can be prevented. Reference numeral 35 denotes a motor cooling centrifugal fan attached to the rotary shaft 25 via a metal insert bush 36 in front of the bearing 34. Here, a central portion bulges forward in a mortar shape and The bearing 34 is disposed so as to overlap the centrifugal fan 35 immediately behind the bulging portion 37. On the side surface of the rear cover 32, exhaust ports 38, 38... Positioned on the radially outer side of the centrifugal fan 35 are formed, while on the side surface of the motor housing 17, Mouth 39, 39 ... is formed. A step portion 17f is formed at the lower fitting portion of the rear cover 32 in the motor housing 17 to prevent the rear cover 32 from rattling.

  Here, the motor housing 17 and the rear cover 32 are coupled to each other in front of the centrifugal fan 35, and this coupling is performed with the projections 17c formed on the inner peripheral sides of the rear ends of the half housings 17a and 17b. The rear cover 32 is connected to a recess 32a formed on the inner peripheral side of the front end. As shown in FIGS. 5 and 6, semi-circular ribs 40 projecting toward the axial center are respectively formed on the convex portions 17 c of the half housings 17 a and 17 b in the coupling portion. 40, a ring-shaped baffle portion 41 having an inner diameter smaller than the outer diameter of the centrifugal fan 35 is formed at the rear end of the motor housing 17. The inner diameter of the rib 40 is smaller than the outer diameter of the stator core 21, and the rib 40 overlaps with the exhaust port 38 to enhance the baffle effect.

On the other hand, the front end of the rotary shaft 25 passes through a bearing retainer 42 held by the motor housing 17 in front of the motor 12 and protrudes forward, and is supported by a bearing 43 held at the rear part of the bearing retainer 42. A pinion 44 is attached to the front end of the rotary shaft 25.
The bearing retainer 42 is formed of a metal disk having a constricted portion at the center, and the rib 45 provided on the inner surface of the motor housing 17 is fitted into the constricted portion, so that the bearing retainer 42 is restricted from moving in the front-rear direction. In this state, it is held by the motor housing 17.
Further, a ring wall 46 having a male threaded portion formed on the outer periphery protrudes forward on the peripheral edge of the front surface of the bearing retainer 42, and a hammer case 47 in which the spindle 14 and the striking mechanism 15 are accommodated on the ring wall 46. Are connected to each other.

  The hammer case 47 is a metal cylindrical body in which a front half portion is tapered to form a front tubular portion 48, and a rear portion is closed by a bearing retainer 42 serving as a lid. A protrusion 49 is formed on the lower surface of the hammer case 47, and in the assembled state, pressing ribs (not shown) protruding from the inner surfaces of the left and right half housings 17a and 17b come into contact with the side surfaces of the protrusion 49, respectively. ing. Further, protrusions (not shown) are formed on the left and right side surfaces of the hammer case 47, and the protrusions are fitted into recesses (not shown) formed on the inner surfaces of the half housings 17a and 17b. ing. The rotation of the hammer case 47 is restricted by the engagement between the protrusion 49 and the holding rib, and the protrusion and the groove.

Between the hammer case 47 and the switch 6, a forward / reverse switching lever 50 of the motor 12 is slidable to the left and right, and an LED 51 for illuminating the front of the anvil 16 is attached obliquely upward. .
Further, a cover 52 is provided in front of the motor housing 17 so as to cover from the front portion of the hammer case 47 to the front cylinder portion 48, and a rubber bumper 53 is attached to the outer peripheral portion of the front end of the cover 52.

A bearing 54 is held at the front portion of the bearing retainer 42, and the rear end of the spindle 14 is pivotally supported by the bearing 54. The spindle 14 has a hollow and disk-shaped carrier part 55 at the rear part, and projects the front end of the rotating shaft 25 and the pinion 44 into a bottomed hole 56 formed in the axial center from the rear surface.
The planetary gear speed reduction mechanism 13 includes an internal gear 57 having internal teeth, and three planetary gears 58, 58... Having external teeth meshing with the internal gear 57. The internal gear 57 is connected to the gear portion 59 coaxially accommodated inside the ring wall 46 of the bearing retainer 42, and is connected to the outer peripheral side of the front portion of the gear portion 59. In the front portion 60, four convex portions 61, 61,... Protrude forwardly at equal intervals in the circumferential direction. Each of the convex portions 61 engages with the four concave portions 62, 62,... Formed in front of the female screw portion on the inner peripheral surface of the hammer case 47, thereby preventing the internal gear 57 from rotating. . The movement in the axial direction is restricted by the rear surface of the front portion 60 coming into contact with the ring wall 46 and the front surface of the convex portion 61 coming into contact with the step portion 63 formed on the front side of the concave portion 62.

Reference numeral 64 denotes a rubber O-ring interposed between the rear end of the gear portion 59 and the front surface of the bearing retainer 42. The O-ring 64 seals between the internal gear 57 and the bearing retainer 42. At the same time, the impact from the internal gear 57 to the bearing retainer 42 is reduced.
The planetary gear 58 is rotatably supported in the carrier portion 55 of the spindle 14 by a pin 65 and meshes with the pinion 44 of the rotating shaft 25. A ring-shaped rising portion 66 is formed on the outer periphery of the front portion of the carrier portion 55 outside the pin 65.

  The striking mechanism 15 includes a hammer 67 mounted on the spindle 14 and a coil spring 68 that urges the hammer 67 forward. First, the hammer 67 has a pair of claws 69 and 69 on the front surface, and is fitted over the outer cam grooves 70 and 70 formed on the inner surface and the inner cam grooves 71 and 71 formed on the surface of the spindle 14. Are coupled to the spindle 14 via balls 72 and 72. A ring-shaped groove 73 is formed on the rear surface of the hammer 67, and the front end of the coil spring 68 is inserted therein. A plurality of balls 74, 74... And a washer 75 are accommodated at the bottom of the groove 73 so as to receive the front end of the coil spring 68. In addition, a taper portion 76 whose diameter increases toward the rear is formed on the outer rear end of the groove 73. On the other hand, the rear end of the coil spring 68 is in contact with the front surface of the carrier portion 55 inside the rising portion 66.

The anvil 16 is pivotally supported by a bearing 77 held by the front cylinder portion 48 of the hammer case 47, and a pair of arms 78, 78 engaged with the claws 69, 69 of the hammer 67 in the rotational direction are provided at the rear end. Is formed. A ring-shaped holding portion 79 protrudes from the front of the arm 78 on the inner surface of the rear surface of the front cylinder portion 48, and a resin washer 80 that receives the arm 78 is fitted to the outside of the holding portion 79. Yes.
A fitting hole 81 is formed in the rear axis of the anvil 16, and the front end of the spindle 14 is coaxially inserted therein.
On the other hand, an insertion hole 82 for receiving a bit (not shown) is formed in the front axis of the anvil 16, and the front end of the anvil 16 includes a ball 83 and a sleeve 84 that prevent the bit inserted into the insertion hole 82. A chuck mechanism is provided.

A part of the surface of the impact driver 1 is covered with an elastomer coating. That is, in the shaded portion shown in FIG. 7, the covering portion includes a first covering portion 85 that covers substantially the entire grip portion 3 and a second covering portion 86 that is separated from the first covering portion 85 and covers the attachment portion 4. And a third covering portion 87 covering from the rear surface to the peripheral surface of the rear cover 32 and a fourth covering portion 88 covering the left and right side surfaces and a part of the upper surface of the motor housing 17. Among these, the 3rd coating | coated part 87 is isolate | separated into the upper part 87a, the middle part 87b, and the lower part 87c, and the 3rd coating | coated part 87 and the 4th coating | coated part 88 are provided in a continuous form, The 1st coating | coated part 85 and the lower portion 87c of the third covering portion 87 are also provided continuously.
In the upper portion 87a of the third covering portion 87, an inwardly bent portion 89 is formed at the front end of the portion covering the peripheral surface of the rear cover 32 as shown in FIG. The bent portion 89 comes into contact with the rear end of the motor housing 17 (half housings 17a and 17b) by screwing the rear cover 32, so that the space between the rear cover 32 and the motor housing 17 is sealed, and water soaks in. It becomes difficult. Further, a penetrating portion 90 that penetrates the rear cover 32 and reaches the inner surface thereof is continuously provided at the lower end of the upper portion 87 a of the third covering portion 87. By this through portion 90, the impact on the upper portion of the rear cover 32 is mitigated, and it is difficult for it to be transmitted forward.

Further, in the middle portion 87b of the third covering portion 87, a cushion portion 91 that fits to the outer surface of the rear cover 32 is formed near the rear of the portion that covers the peripheral surface of the rear cover 32, as shown in FIG. ing. The cushion portion 91 can suppress excessive deformation of the rear cover 32 during screw tightening, and makes it difficult for the impact from the rear cover 32 to be transmitted to the motor housing 17. In the middle portion 87b, the head of the screw 33 does not protrude from the middle portion 87b. Thereby, hooking and scratching by the screw 33 are prevented.
In addition, as shown in FIG. 6, an extension portion 92 that penetrates the rear cover 32 and reaches the inner surface thereof is continuously provided in a portion of the middle portion 87 b that covers the peripheral surface of the rear cover 32. The extension 92 reduces the impact on the rear cover 32. The middle portion 87b of the elastomer is provided on the radially outer side of the screw boss 17e together with the extension portion 92, so that the impact resistance of the screw boss 17e is also improved. The screw boss 17e also functions as a detent for the rear cover 32.
Further, as shown in FIG. 6, the lower portion of the front end of the rear cover 32 is a detent portion 93, 93 that is separated into right and left, and is fitted from the outside between the half housings 17 a, 17 b and the rib 40. Thus, the rear cover 32 is prevented from rotating.

  In the covering portion, thick portions 94a, 94b, and 94c in which the thickness of the elastomer is partially large are formed on both the left and right surfaces of the attachment portion 4, the left and right surfaces of the rear cover 32, and the left and right surfaces of the cover 52. , Projecting outward than the other parts. Therefore, when the impact driver 1 is placed sideways on a flat surface such as a floor, it is supported at three points by the thick portions 94a to 94c, and the surface of the impact driver 1 is less likely to be damaged or damaged. Yes.

  In the impact driver 1 configured as described above, 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 25 rotates. That is, the controller 9 obtains a rotation detection signal indicating the position of the sensor permanent magnet 28 of the rotor 20 output from the rotation detection element of the sensor circuit board 29, acquires the rotation state of the rotor 20, and sets the acquired rotation state. Accordingly, ON / OFF of each switching element is controlled, and the rotor 20 is rotated by causing current to flow sequentially to each coil 24 of the stator 19.

  Then, the planetary gear 58 that meshes with the pinion 44 revolves within the internal gear 57, and the spindle 14 is decelerated and rotated via the carrier portion 55. Therefore, the hammer 67 is also rotated to rotate the anvil 16 via the arm 78 with which the claw 69 is engaged, so that 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 67 moves backward along the inner cam groove 71 of the spindle 14 against the bias of the coil spring 68, and the claw 69 moves to the arm 69. When separated from 78, the hammer 67 rotates forward by the biasing force of the coil spring 68 and the guide of the inner cam groove 71 to reengage the claw 69 with the arm 78, and the rotational impact force (impact) is applied to the anvil 16. generate. By repeating this, further tightening is possible.

  When the centrifugal fan 35 rotates along with the rotation of the rotary shaft 25, the outside air taken in from the intake port 39 passes through the motor 12 and cools, and then is discharged from the exhaust port 38. Since the baffle part 41 is formed between the centrifugal fan 35 and the centrifugal fan 35, the air that has passed through the motor 12 reaches the centrifugal fan 35 without being squeezed by the baffle part 41 without expanding the flow path, and without being disturbed. 38 is discharged.

  Thus, according to the impact driver 1 of the said form, the convex part 17c is formed in the connection end part with the rear cover 32 in the motor housing 17, and the recessed part 32a is formed in the connection end part with the motor housing 17 in the rear cover 32, respectively. Even if the motor housing 17 is closed by the rear cover 32 by providing the baffle portion 41 projecting toward the shaft center side of the motor housing 17 at the coupling end portion on the motor housing 17 side, it is compact. The baffle function can be easily obtained while maintaining the above.

As shown in FIG. 8, the concave and convex portions of the wax joint may be reversed from the above-described configuration by providing a concave portion 17d on the motor housing 17 side and a convex portion 32b on the rear cover 23 side. Also in this case, the baffle portion 41 is provided in the motor housing 17, but the baffle portion 41 can also be provided on the convex portion 32 b of the rear cover 23.
Further, the baffle portion is not limited to a structure provided integrally with the motor housing and the rear cover, and a baffle as a separate part can be fixed between the motor housing and the rear cover. However, when the baffle portion is provided integrally with the motor housing and the rear cover as in the above-described embodiment, there is an advantage that the strength of the toy joint is increased.
Further, as shown in FIG. 9, the baffle portion is omitted because the baffle function can be obtained if the inner diameter of the motor housing 17 is smaller than the inner diameter of the rear cover 32 in a state where the centrifugal fan 35 is accommodated in the rear cover 32. can do. Also in this case, the unevenness of the wire-bonding may be reversed as shown in FIG.

  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 c.. Convex part, 19 .. Stator, 20 .. Rotor, 25 .. Rotating shaft, 32 .. Rear cover, 32 a. 41 .. Baffle part, 47 .. Hammer case, 67 .. Hammer, 68 .. Coil spring, 85 .. First covering part, 86 .. Second covering part, 87 .. Third covering part, 88. 4 coating | cover part, 94a-c .. Thick part.

Claims (6)

A motor comprising a stator and a rotor;
A tip tool driven by the motor;
A cylindrical motor housing in which the motor is accommodated;
A cap-shaped rear cover for closing the rear end of the motor housing,
The rear cover holds a bearing that supports the rear end of the rotating shaft of the rotor and is coupled to the motor housing with a screw from the rear, and at least a part of the rear cover is formed with an elastomer covering portion. While
An electric tool , wherein a screw boss into which the screw is screwed into the motor housing protrudes rearward from a rear end surface of the motor housing, and the screw boss is fitted to the rear cover . The electric power tool according to claim 1, wherein the covering portion is also formed on a radially outer side of a portion where the screw boss is fitted .   3. The electric motor according to claim 1, wherein a concave portion is formed in one of the coupling end portions of the motor housing and the rear cover, and a convex portion that fits into the concave portion is formed in the other, respectively. tool. The flat surface of the left-right direction is formed in the lower surface of the said back cover, The flat receiving surface which receives the said flat surface of the said back cover is formed in the said motor housing. 4. The electric tool according to any one of 3.   5. The cover according to claim 1, wherein the covering portion is also formed on an outer surface of the motor housing, and the covering portion of the rear cover and the covering portion of the motor housing are continuously connected. The electric tool described.   The power tool according to claim 5, wherein at least the covering portion of the motor housing is provided with an abutting portion that partially abuts on the flat surface when placed on the flat surface in a lateral direction.

Images