JP6530012B2 - Impact tool - Google Patents

Description

  The present invention relates to an impact tool capable of applying a rotary striking force to an anvil holding a bit by a hammer.

As shown in Patent Document 1, the impact tool connects a hammer via a ball to a spindle to which rotation is transmitted from a motor, and engages the hammer with an anvil on which a bit is mounted by a coil spring mounted on the spindle. At the same time, in response to the increase of the torque to the anvil, the hammer is disengaged from the anvil to generate the rotary impact force (impact) intermittently.
In such an impact tool, grease is contained in a hammer case that accommodates the impact mechanism to lubricate each component.

JP, 2013-119149, A

  In the conventional impact tool described above, when an impact occurs, the hammer axially slides along the spindle to engage with the anvil.

  Therefore, an object of the present invention is to provide an impact tool capable of holding, in a hammer case, a washer that receives an arm provided at the rear end of an anvil.

In order to achieve the above object, the invention according to claim 1 is a motor, a spindle rotated by the motor, a hammer capable of moving back and forth with respect to the spindle, and an arm at which the hammer engages in a rotational direction. An impact tool comprising: an anvil disposed on the front side of a hammer; a front tubular portion pivotally supporting the anvil via a bearing; and a hammer case accommodating the hammer and the arm; ,
A ring-shaped holding portion is protruded from the rear surface of the front cylinder portion, and a washer for receiving the arm is fitted to the outside of the holding portion, the bearing is a needle bearing, and the needle bearing is held radially outward The portion and the washer are disposed, and the rear end of the needle bearing is located forward of the rear end of the holding portion.
In order to achieve the above object, the invention according to claim 2 is a motor, a spindle rotated by the motor, a hammer movable back and forth with respect to the spindle, and a rear end of an arm engaged with the hammer in a rotational direction. An impact tool comprising: an anvil disposed on the front side of a hammer; a front tubular portion pivotally supporting the anvil via a bearing; and a hammer case accommodating the hammer and the arm; ,
A ring-shaped holding portion is protruded from the rear surface of the front cylinder portion, and a washer for receiving the arm is fitted to the outside of the holding portion, the bearing is a needle bearing, and the needle bearing is held radially outward A ring-shaped gap is formed between the outer periphery of the washer and the inner periphery of the hammer case while the part and the washer are disposed, and the washer has the entire front view as the arm rotation region and the front and rear It is characterized by overlapping in the direction.

  According to the present invention, the washer for receiving the arm provided at the rear end of the anvil can be held in the hammer case.

It is a partial longitudinal cross-sectional view of an impact driver. It is an AA line sectional view. It is a BB sectional drawing. It is a top view of a spindle. It is explanatory drawing which shows the example of a change of a grease supply path. It is explanatory drawing which shows the example of a change of a grease supply path. It is explanatory drawing which shows the example of a change of a grease supply path. It is explanatory drawing which shows the example of a change of a grease supply path. It is explanatory drawing which shows the example of a change of a grease supply path. It is explanatory drawing which shows the example of a change of a grease supply path. It is explanatory drawing which shows the example of a change of the holding structure of a washer, (A) is a longitudinal cross-section of a front-end part, (B) shows CC cross section, respectively. It is explanatory drawing which shows the example of a change of the holding structure of a washer, (A) is a longitudinal cross-section of a front end part, (B) shows a DD sectional view, respectively. It is a partial longitudinal cross-sectional view which shows the example of a change of the guide structure of a forward / reverse switching lever. It is an EE sectional view taken on the line.

Hereinafter, embodiments of the present invention will be described based on the drawings.
1 is a partial longitudinal sectional view of an impact driver which is an example of an impact tool, FIG. 2 is a sectional view taken along the line A-A, FIG. 3 is a sectional view taken along the line B-B. 1 has a main body 2 with the right side as the front), and a grip 3 projecting downward from the main body 2, and an unshown attachment provided at the lower end of the grip 3 The battery pack is attached. The switch 4 in which the trigger 5 is projected forward is accommodated in the upper part of the grip portion 3.

  An anvil 10 projects forward from the front end of the main body 2, with the motor 6, the planetary gear reduction mechanism 7, the spindle 8, and the striking mechanism 9 housed in this order from the rear from the rear. The main body 2 has a main housing 11 formed by assembling a pair of left and right half housings 11a and 11b shown in FIG. 3 by a plurality of screws 12, 12... Housed in In each of the half housings 11a and 11b, grip housings 3a and 3b obtained by dividing the grip 3 into right and left are integrally formed, respectively, and the grip 3 also has a pair of left and right grip housings 3a and 3b with a plurality of screws 12 , 12 · · · formed by assembling.

  The motor 6 is an inner rotor type brushless motor having a stator 13 and a rotor 14. First, the stator 13 is wound around the stator core 15 via the stator core 15, the front insulating member 16 and the rear insulating member 17 provided before and after the stator core 15, the front insulating member 16 and the rear insulating member 17. And the plurality of coils 18, 18. Further, the rotor 14 is disposed on the outer side of the rotary shaft 19 located at the axial center, the cylindrical rotor core 20 disposed around the rotary shaft 19, and the rotor core 20, and is cylindrical and circumferentially It has permanent magnets 21 of alternating polarity, and a plurality of sensor permanent magnets 22, 22... Radially disposed on the front side of these. A sensor circuit board 23 mounted with three rotation detection elements (not shown) for detecting the position of the sensor permanent magnet 22 of the rotor 14 and outputting a rotation detection signal at the front end of the front insulating member 16 by a screw 24 It is fixed. The terminal of the coil 18 is electrically connected to the sensor circuit board 23 in a penetrating state. The switching element for switching the coil 18 is mounted on a control substrate (not shown) provided inside the mounting portion of the battery pack.

  The stator 13 is held coaxially with the main body 2 by ribs 25 provided to protrude on the inner surface of the main body housing 11. A cap-like rear housing 26 is attached to the rear surface of the main body housing 11 from the rear by a screw (not shown), after which a bearing 27 held by the housing 26 pivotally supports the rear end of the rotary shaft 19 . The reference numeral 28 denotes a centrifugal fan for motor cooling attached to the rotary shaft 19 in front of the bearing 27 via a metal insert bush 29. Here, a bulging portion 30 in which a central portion bulging forward in a bowl shape and The bearing 27 is arranged to overlap the centrifugal fan 28 just behind the bulge 30. In the side surface of the rear housing 26, exhaust ports 31, 31 ... located on the radial direction outer side of the centrifugal fan 28 are formed, and the side surface of the main body housing 11 is illustrated on the radial direction outer side of the sensor circuit board 23. Intake is not formed.

On the other hand, the front end of the rotary shaft 19 projects forward through the bearing retainer 32 held in the main body housing 11 in front of the motor 6 and is supported by a bearing 33 held in the rear of the bearing retainer 32. 34 is a sleeve mounted on the rotary shaft 19 between the rotor core 20 and the bearing 33, and 35 is a pinion attached to the front end of the rotary shaft 19.
The bearing retainer 32 is a metal disk shape having a constricted portion in the center, and the rib 36 provided on the inner surface of the main body housing 11 fits in the constricted portion, thereby restricting the movement of the bearing retainer 32 in the front-rear direction It is held by the main body housing 11 in the closed state. On the front and rear surfaces of the bearing retainer 32, heat sinking recesses 37 are formed.
Further, a ring wall 38 having a male screw formed on the outer periphery thereof is protruded forward from the front peripheral edge of the bearing retainer 32. A hammer case 39 accommodating the spindle 8 and the striking mechanism 9 in the ring wall 38. Female screw part is connected.

  The hammer case 39 is a metal cylindrical body in which the front half portion is tapered to form the front cylinder portion 40, and the female screw portion formed on the inner periphery of the rear end is screwed to the male screw portion of the ring wall 38 As a result, the rear portion is closed by the bearing retainer 32 serving as a lid. A projection 41 is formed on the lower surface of the hammer case 39, and in an assembled state, pressing ribs (not shown) provided on the inner surfaces of the left and right half housings 11a and 11b respectively contact the side surfaces of the projection 41 ing. Further, protrusions (not shown) are formed on the left and right side surfaces of the hammer case 39, and the protrusions are fitted into not-shown recesses formed in the inner surfaces of the half housings 11a and 11b. ing. The rotation of the hammer case 39 is restricted by the engagement of the projection 41 and the pressing rib, and the projection and the recess.

A forward / reverse switching lever 42 of the motor 6 is slidably provided to the left and right between the hammer case 39 and the switch 4, and an LED 43 for illuminating the front of the anvil 10 is attached obliquely upward in front of it. . At the center of the front surface of the forward / reverse switching lever 42, an engagement protrusion 44 is formed which engages with the switching lever 4a provided on the top surface of the switch 4. The pressing piece 45 protruding from the half housing 11 a is located on the upper side of the engaging protrusion 44 so that the upper surface of the engaging protrusion 44 and the lower end of the pressing piece 45 are in contact with each other. Thus, the left and right slides of the engagement protrusions 44 are guided. Further, the central portion of the forward / reverse switching lever 42 is thin on the upper surface thereof by forming the notch 46. The half housings 11a and 11b are respectively formed with guide portions 11c on which left and right upper surfaces 42a slide except for the notch 46 of the forward / reverse switching lever 42.
Further, a cover 47 is provided on the front of the main body housing 11 so as to cover from the front of the hammer case 39 to the front cylindrical portion, and a rubber bumper 48 is attached to the front end outer peripheral portion of the cover 47.

A bearing 49 is held at the front of the bearing retainer 32, and the rear end of the spindle 8 is supported by the bearing 49. As shown in FIG. 4, the spindle 8 has a hollow disk-like carrier portion 50 at its rear portion, and the rotary shaft 19 is provided in a bottomed hole 51 (which may be a through hole) formed in the axial center from the rear surface. And the pinion 35 are protruded.
The planetary gear reduction mechanism 7 includes an internal gear 52 having internal teeth, and three planetary gears 53, 53... Having external teeth meshing with the internal gear 52. The internal gear 52 is continuous with a gear portion 54 coaxially accommodated inside the ring wall 38 of the bearing retainer 32 and a front outer peripheral side of the gear portion 54, and a front portion 55 larger in diameter than the gear portion 54. In the front portion 55, as shown in FIG. 3, four convex portions 56, 56,... Are provided forwardly at equal intervals in the circumferential direction. The internal gear 52 is prevented from rotating by engaging the respective projections 56 with the four recesses 57 formed on the front of the female screw on the inner peripheral surface of the hammer case 39. . The movement in the axial direction is restricted by the rear surface of the front portion 55 abutting on the ring wall 38 and the front surface of the convex portion 56 abutting on the step portion 58 formed on the front side of the concave portion 57.

Reference numeral 59 denotes a rubber O-ring interposed between the rear end of the gear portion 54 and the front surface of the bearing retainer 32. The O-ring 59 seals between the internal gear 52 and the bearing retainer 32. At the same time, the impact from the internal gear 52 to the bearing retainer 32 is also alleviated.
The planetary gear 53 is rotatably supported by the pin 60 in the carrier portion 50 of the spindle 8 and meshes with the pinion 35 of the rotating shaft 19. A ring-shaped rising portion 61 is formed on the front outer periphery of the carrier portion 50 outside the pin 60.

  The striking mechanism 9 includes a hammer 62 mounted on the spindle 8 and a coil spring 63 for biasing the hammer 62 forward. First, the hammer 62 has a pair of claws (not shown) on the front surface, and is fitted across the outer cam grooves 64 and 64 formed on the inner surface and the inner cam grooves 65 and 65 formed on the surface of the spindle 8 It is connected to the spindle 8 via balls 66, 66. Further, a ring-shaped groove 67 is formed on the rear surface of the hammer 62, and the front end of the coil spring 63 is inserted therein. At the bottom of the groove 67, a plurality of balls 68, 68... And a washer 69 are accommodated to receive the front end of the coil spring 63. Further, on the outside of the rear end of the groove 67, there is formed a tapered portion 70 which is expanded in diameter toward the rear. On the other hand, the rear end of the coil spring 63 is in contact with the front surface of the carrier portion 50 inside the rising portion 61.

The anvil 10 is pivotally supported by a bearing (here, a needle bearing) 71 held by the front cylindrical portion 40 of the hammer case 39, and has a pair of arms 72 rotatably engaged with the claws of the hammer 62 at its rear end. , 72 are formed. As shown in FIG. 2, a ring-shaped holding portion 73 is provided in front of the arm 72 and on the rear surface inner peripheral side of the front cylinder portion 40, and made of resin that receives the arm 72 outside the holding portion 73. A washer 74 is fitted. Thus, since the washer 74 is disposed radially outside the rear end portion of the bearing 71, it is compact. In particular, since a needle bearing is used, the holding width for centering the axial center of the anvil 10 can be reduced.
Further, a fitting hole 75 as a fitting portion is formed in the rear surface axial center of the anvil 10, and the front end of the spindle 8 is coaxially inserted into the fitting hole 75. A front bottomed hole 76 is also formed at the front end axial center of the spindle 8. On the other hand, an insertion hole 77 for receiving a bit (not shown) is formed in the front axial center of the anvil 10, and the front end of the anvil 10 comprises a ball 78 and a sleeve 79 etc. for retaining the bit inserted in the insertion hole 77. A chuck mechanism is provided.

  Then, in the spindle 8, a pair of grease supply paths 80, 80 communicating with the bottomed hole 51 and opened at the outer peripheral portion of the spindle 8 are formed behind the inner cam groove 65 as shown in FIG. ing. The grease supply passage 80 is formed orthogonal to the bottomed hole 51 so that the inner peripheral portion of the hammer 62 overlaps the opening on the outer peripheral portion side of the spindle 8 at the forward position of the hammer 62 shown in FIG. ing. On the other hand, in the inner peripheral portion of the hammer 62, a recessed groove 81 located on the outside of the grease supply passage 80 at the retracted position of the hammer 62 at the time of impact occurrence is formed in the circumferential direction. Therefore, the opening of the grease supply passage 80 is always positioned at the inner peripheral portion of the hammer 62 regardless of the back and forth movement of the hammer 62.

  In the impact driver 1 configured as described above, when the trigger 5 is pushed in and the switch 4 is turned on, the motor 6 is supplied with power and the rotating shaft 19 rotates. That is, the microcomputer of the control board obtains the rotation detection signal indicating the position of the sensor permanent magnet 22 of the rotor 14 output from the rotation detection element of the sensor circuit board 23, acquires the rotation state of the rotor 14, and acquires the rotation According to the state, ON / OFF of each switching element is controlled, and the rotor 14 is rotated by supplying current to each coil 18 of the stator 13 in order.

  Then, the planetary gear 53 meshing with the pinion 35 revolves within the internal gear 52 and decelerates and rotates the spindle 8 via the carrier portion 50. Therefore, the hammer 62 is also rotated to rotate the anvil 10 via the arm 72 engaged with the claw, and screwing with a bit becomes possible. As screw tightening progresses and the torque of the anvil 10 increases, the hammer 62 retracts against the bias of the coil spring 63 while rolling the ball 66 along the inner cam groove 65 of the spindle 8, and the claw is the arm 72 The hammer 62 rotates forward to engage the claw again with the arm 72 by the bias of the coil spring 63 and the guide of the inner cam groove 65 to generate a rotational impact force (impact) on the anvil 10 . This repetition enables further tightening.

  Here, the grease accommodated in the hammer case 39 lubricates the pinion 35 and the internal gear 52 so that the grease is also disposed in the bottomed hole 51 of the spindle 8. Therefore, even when grease on the outer peripheral portion of the spindle 8 is removed when the hammer 62 moves backward along the spindle 8 at the time of impact occurrence, new grease is supplied from the bottomed hole 51 to the grease supply passage 80, 80. Is supplied to the inner peripheral portion of the hammer 62 via the In particular, the concave groove 81 of the hammer 62 makes it easy for the grease to be stored in the inner peripheral portion of the hammer 62. Therefore, even when an impact occurs, the lubrication of the inner peripheral portion of the hammer 62 is maintained.

  Thus, according to the impact driver 1 of the above embodiment, by providing the grease supply passage 80 for supplying grease to the inner peripheral portion of the hammer 62, the grease can be reliably supplied to the inner peripheral portion of the hammer 62. And maintain favorable lubricity.

In the above embodiment, although the grease supply passage 80 is formed to be orthogonal to the axis of the spindle 8, as shown in FIG. 5, the grease supply passages 80, 80 are formed to be inclined from the axis of the spindle 8. You can also. In this case, the rotation of the spindle 8 supplies the inner peripheral portion of the hammer 62 little by little. Further, as shown in FIG. 6, the opening of the grease supply passage 80 may be provided forward of FIG. 5 so that the opening of the grease supply passage 80 overlaps the concave groove 81 on the hammer 62 side when the hammer 62 is advanced. In this way, grease tends to be accumulated in the concave groove 81.
Further, the opening of the grease supply passage 80 is not necessarily always overlapped with the inner peripheral portion of the hammer 62. As shown in FIG. 7, the grease supply passage 80 is provided at the rear of FIG. In this case, the opening may not overlap with the inner peripheral portion of the hammer 62, and the opening may overlap with the inner peripheral portion at the retracted position of the hammer 62 indicated by a two-dot chain line.

Furthermore, not only from the bottomed hole 51 side of the spindle 8, but as shown in FIG. 8, the front bottomed hole 76 of the spindle 8 is extended backward, and grease is supplied from the opening to the inner periphery of the hammer 62 The passage 80 may be sloped. In this way, lubricating grease for the anvil 10 and the spindle 8 is supplied to the inner periphery of the hammer 62.
In addition, as shown in FIG. 9, a through hole 82 communicating with the bottomed hole 51 and the front bottomed hole 76 and penetrating the axial center of the spindle 8 is formed, and a grease supply passage is orthogonally formed from the through hole 82. 80 can also be provided. In this case, the grease is supplied from both the front side and the rear side of the spindle 8 and the weight reduction of the spindle 8 is also achieved. However, since the grease reaching the fitting hole 75 of the anvil 10 by the through hole 82 wraps around the front end of the spindle 8 and reaches the inner peripheral portion of the hammer 62, the grease supply passage 80 of the spindle 8 can be omitted.

Then, the grease supply passage is not limited to the structure in which the grease supply passage is formed on the spindle 8 side, but as shown in FIG. 10, the grease supply passage 83 communicating the groove 67 of the hammer 62 and the inner peripheral portion is made orthogonal to the hammer 62 side. It is also conceivable to form.
In each of these embodiments, the grease supply passage is not limited to a pair, and may be provided in three or more places, or conversely in one place. Further, the concave groove 81 of the hammer 62 may not be present.

On the other hand, the holding of the washer 74 for receiving the arm 72 of the anvil 10 is not limited to the structure in which the holding portion 73 is protruded on the inner periphery of the rear end of the front cylinder portion 40, as shown in FIG. It can also be performed by forming a step 84 outside the end and fitting the outer surface of the washer 74 inside the step 84.
Further, the structure is not limited to such a structure using the holding portion or the step portion, but as shown in FIG. 12, the rear end of the bearing 71 is extended by moving the bearing 71 long or backward. It can also be made to project more rearward than the rear end face of the portion 40, and the washer 74 can be fitted to the bearing 71 for positioning. In this case, the shape of the hammer case 39 is simplified as compared with the case of FIGS. 1 and 11, and the axial length can be shortened while maintaining the structure in which the anvil 10 can be rotated with high accuracy.

Further, as shown in FIGS. 13 and 14, the guide structure of the forward / reverse switching lever 42 also has a projection 85 projecting at the center of the rear surface of the forward / reverse switching lever 42, and this projection 85 integrally projects from the half housing 11a. It can also be realized by sliding in contact with the lower surface of the provided guide piece 86. Here, the projection 85 is fitted in the recess 86 a provided on the lower surface of the guide piece 86, and the right wall 86 b and the left wall 86 c in the recess 86 a serve as the left and right stoppers of the forward / reverse switching lever 42.
In this way, the left and right slidability of the forward / reverse switching lever 42 made compact by forming the notch 46 at the center of the upper surface is improved.
The forward / reverse switching lever 42 may be overlapped with the lower surface of the hammer case 39 in the left-right direction.
With these structures, the following configurations are also considered as inventions.
(1) The needle bearing is disposed on the inner peripheral side of the washer.
(2) A configuration in which the forward / reverse switching lever is guided by the housing at the front and / or the rear.
(3) A configuration in which the guide portion of the forward / reverse switching lever is provided below the protrusion of the hammer case.
(4) The structure which guides the engagement protrusion of a forward / reverse switching lever.

  In addition, the present invention can be applied to other impact tools such as an impact wrench as long as the power tool is not limited to the impact driver, and provided that it has an impact mechanism by a hammer. The inventions of (2) and (4) can also be applied to a power tool such as a driver drill.

  1 · · · Impact driver, 2 · · · body portion · 3 · · · grip portion 6 · · · motor 7 · · planetary gear reduction mechanism 8 · · · spindle 9 · · striking mechanism 10 · · anvil 11 · · · Body housing 13 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · switching lever, 51 · · · bottomed Hole · · · · hammer · 63 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 80 Hole.

Claims (2)

Motor,
A spindle rotated by the motor;
A hammer movable back and forth with respect to the spindle;
An anvil at the rear end of the hammer having an arm engaged in a rotational direction, the anvil disposed on the front side of the hammer;
An impact tool comprising: a front cylindrical portion pivotally supporting the anvil via a bearing; and a hammer case in which the hammer and the arm are accommodated,
A ring-shaped holding portion is protruded from the rear surface of the front cylinder portion,
A washer for receiving the arm is fitted to the outside of the holding portion,
The bearing is a needle bearing, and the holding portion and the washer are disposed radially outward of the needle bearing, and the rear end of the needle bearing is located on the front side of the rear end of the holding portion Impact tool that is characterized by Motor,
A spindle rotated by the motor;
A hammer movable back and forth with respect to the spindle;
An anvil at the rear end of the hammer having an arm engaged in a rotational direction, the anvil disposed on the front side of the hammer;
An impact tool comprising: a front cylindrical portion pivotally supporting the anvil via a bearing; and a hammer case in which the hammer and the arm are accommodated,
A ring-shaped holding portion is protruded from the rear surface of the front cylinder portion,
A washer for receiving the arm is fitted to the outside of the holding portion,
The bearing is a needle bearing, and the holding portion and the washer are disposed radially outward of the needle bearing, and a ring is disposed radially outward of the washer and against the inner periphery of the hammer case. An impact tool characterized in that a gap of a shape of a circle is formed, and the washer is overlapped in the front-rear direction with the rotation area of the arm as a whole in a front view.

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