JP6668110B2 - Impact tool - Google Patents

Description

  The present invention provides a tool holder for holding a tip tool, which is provided in a housing so as to be capable of moving back and forth and protruding forward and forcing the clutch for engaging and disengaging from a conversion member to move forward and backward with the tool holder. Also, the present invention relates to a hammer drill or other striking tool capable of selecting a striking mode (hammer mode or hammer drill mode) by engaging a retracted clutch with a conversion member.

  For example, in a hammer drill, as disclosed in Patent Literature 1, a tool holder for holding a tool bit such as a drill bit is provided in a housing so as to be able to move back and forth and protrude forward, and the rotation of a motor is provided in the housing. The transmitted intermediate shaft is provided in parallel with the tool holder, and the intermediate shaft converts the rotation of the intermediate shaft into reciprocating motion of a striking member such as a piston cylinder housed in the tool holder. There is known a conversion member which is provided with a clutch which moves forward and backward in association with the forward and backward movement of the tool holder and which engages with and disengages from the conversion member. In this hammer drill, the drill mode can be selected by restricting the retraction of the tool holder at a position where the clutch does not engage with the conversion member by an external operation, and the retraction of the tool holder can be adjusted to the position where the clutch engages with the conversion member. The hammer drill mode can be selected by allowing.

Japanese Patent No. 4746920

  In this hammer drill, the operator pushes the tool bit into the ground or the like to retract the tool holder, and at the same time, the retracted clutch is engaged with the conversion member. At the same time, the clutch may move forward to release the engagement with the conversion member, and the hitting operation may be interrupted.

  In view of this, the present invention, even if the retracted clutch is engaged with the conversion member together with the tool holder protruded and urged forward, and the striking mode can be selected, the engagement of the clutch with the conversion member is prevented. It is an object of the present invention to provide a striking tool which is hard to come off and can maintain good workability.

In order to achieve the above object, an invention according to claim 1 includes a housing for accommodating a motor, a tool holder capable of holding a tip tool, being movable back and forth in the housing, and being provided to urge forward. A striking member provided to be movable back and forth into the tool holder, an intermediate shaft provided in the housing in parallel with the tool holder and transmitting the rotation of the motor, and a striking member provided on the intermediate shaft to rotate the intermediate shaft. A conversion member for converting to reciprocating motion, and a clutch provided integrally rotatably on the intermediate shaft and slidable in the axial direction, moving back and forth in cooperation with the tool holder, and engaging with the conversion member at a predetermined retreat position. A striking tool, wherein engagement between the conversion member and the clutch is performed by engaging a convex portion provided on one of the conversion members and a concave portion provided on the other in a rotational direction,
The contact surface between the convex portion and the concave portion is closer to itself than the proximal contact point where it is in contact with the mating surface on the other side, and the distal contact point where the meshing surface on the other side is in contact with the mating surface on the other side. Each include a shape that is displaced to the side of engagement with the partner in the rotation direction, and in the state of engagement between the projections and the recesses, the resistance between the conversion member and the clutch in the separation direction due to interference between the engagement surfaces of each other. While
The end surface where the concave portion is formed is characterized in that a relief portion is formed in which the inner surface opposite to the meshing surface in the concave portion is shallower than the inner surface on the meshing surface side .
According to a second aspect of the present invention, in the configuration of the first aspect, when the convex portion and the concave portion are engaged with each other, the entire surfaces between the proximal contact point and the distal contact point on the mutual engagement surfaces contact each other. Is characterized by being in contact with.
According to a third aspect of the present invention, in the configuration of the first or second aspect, the convex portion is formed such that the width in the rotation direction is wider at the tip side than at the root side, and the inclined outer surface is a meshing surface. The concave portion has a tapered shape, and has a reverse tapered shape in which the width in the rotational direction is formed to be narrower on the open side than on the bottom side, and the inclined inner surface is a meshing surface.
According to a fourth aspect of the present invention, in the configuration of the third aspect, the inclination angle of both the engaging surfaces of the convex portion and the concave portion is within a range of 5 ° to 20 ° with respect to a straight line parallel to the axis of the intermediate shaft. It is characterized by the following.

According to the first aspect of the present invention, even if the retreating clutch is engaged with the conversion member together with the tool holder which is projected and urged forward, the striking mode can be selected by the conversion member. The clutch is less likely to be disengaged, and good workability can be maintained.
In addition, the formation of the escape portion allows the convex portion to easily enter the concave portion, so that the meshing is smoothly performed.
According to the second aspect of the present invention, in addition to the effect of the first aspect, the entire surfaces of the meshing surfaces come into contact with each other, so that interference between the meshing surfaces in the separating direction increases, and the engagement of the clutch is further improved. It is hard to come off.
According to the third aspect of the present invention, in addition to the effects of the first or second aspect, the convex portion and the concave portion are formed to have an inversely tapered shape, so that the engagement surface that is difficult to be disengaged can be easily formed.
According to the fourth aspect of the invention, in addition to the effect of the third aspect, by setting the inclination angle of the meshing surface in the range of 5 ° to 20 °, it is possible to set a meshing surface that is easily meshed and hardly comes off.

1 is an overall view of a hammer drill (drill mode). 1 is an overall view of a hammer drill (hammer drill mode). FIGS. 5A and 5B are explanatory diagrams of a meshing portion between a clutch and a boss sleeve, in which FIG. 7A shows a state before meshing and FIG. 7A is a diagram illustrating a drill mode, and FIG. 6A illustrates a switching position of a mode switching lever, and FIG. 6B illustrates an inside of a front housing. 7A is a diagram illustrating a hammer drill mode, in which FIG. 7A illustrates a switching position of a mode switching lever, and FIG. 7A is an explanatory view of a hammer mode, in which FIG. 7A shows a switching position of a mode switching lever, and FIG. FIG. 6 is a sectional view taken along line AA of FIG. 5. FIG. 8 is a sectional view taken along line BB of FIG. 7. It is explanatory drawing which shows the positional relationship of a slide plate and a mode switching lever in a hammer mode.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an overall view showing an example of a hammer drill which is also a striking tool. The inside of a main body housing is omitted except for a brushless motor and a switch. The hammer drill 1 has a tapered cylindrical front housing 5 for housing an output portion 6 protruding forward from an upper portion of the front side (left side in FIG. 1) of a main body housing 2 for housing a brushless motor 3 and a controller (not shown). A handle 7 for accommodating a switch 8 having a trigger 9 is provided at a position on the rear upper portion of the main body housing 2 directly behind a tool holder 17 described later. Reference numeral 10 denotes a battery pack which is mounted on the lower rear part of the main body housing 2 and serves as a power source.
The brushless motor 3 is housed in the main body housing 2 in an inclined posture in which the rotating shaft 4 is directed upward and obliquely rearward, and the first gear (bevel gear) 11 provided at the tip of the rotating shaft 4 is moved inside the front housing 5. To protrude.

An inner housing 12 is held inside the front housing 5. The inner housing 12 has an elliptical plate-shaped rear holding portion 13 fitted to the rear end of the front housing 5 and assembled between the main housing 2, and a support portion 14 protruding forward from the holding portion 13. And a ring-shaped front holding portion 15 which is screwed to the front end of the support portion 14. The first gear 11 of the rotating shaft 4 is supported by a bearing 16 held by a rear holding portion 13 and protrudes into the front housing 5.
A cylindrical tool holder 17 and an intermediate shaft 18 located directly below the tool holder 17 are accommodated in the front housing 5 in front of the inner housing 12 in the front-rear direction. First, the tool holder 17 is rotatably and longitudinally supported by a bearing 19 provided at a front portion of the front housing 5 and a metal bearing 20 pressed into the front holding portion 15 of the inner housing 12.

  A flange 21 is formed on the outer periphery of the rear portion of the tool holder 17, and a locking plate 23 and a receiving plate 24 are provided behind the flange 21 via a washer 22 in an overlapping state. The tool holder 17 is normally urged by a coil spring 25 provided between the receiving plate 24 and the front holding portion 15 to a forward position where a stop ring 26 provided on the outer periphery of the front portion comes into contact with the bearing 19. The retraction of the tool holder 17 is restricted at the position in FIG. 2 where the receiving plate 24 contacts the metal bearing 20. As shown in FIG. 4, a regulating plate 27 having an inverted L-shape in side view is formed integrally with the lower side of the receiving plate 24.

On the outer periphery of the tool holder 17, between the flange 21 and the retaining ring 26, there is provided a torque limiter which rotates integrally with the tool holder 17 by being pressed by a clutch plate 29 provided on the tool holder 17 by a coil spring 28. A fourth gear 30 is provided.
Further, a piston cylinder 31 as a striking member is accommodated in the rear inside of the tool holder 17 so as to be movable back and forth. A striker 33 is housed in the piston cylinder 31 via an air chamber 32 so as to be able to reciprocate back and forth. An impact bolt 34 is accommodated in front of the striker 33, and can be brought into contact with a rear end of a bit 35 inserted into a front end of the tool holder 17. An operation sleeve 36 for attaching and detaching the bit 35 is provided at the front end of the tool holder 17.

  Next, the intermediate shaft 18 is rotatably supported by a front bearing 37 provided on the front housing 5 and a rear bearing 38 provided on the rear holding portion 13 of the inner housing 12, and a second gear ( (A bevel gear) 39 meshes with the first gear 11 of the rotating shaft 4. A boss sleeve 40 as a conversion member rotatable separately from the intermediate shaft 18 and a clutch 41 integrally rotating with the intermediate shaft 18 are provided on the intermediate shaft 18 in front of the second gear 39 from the rear. . The boss sleeve 40 has a swash bearing 42 inclined from the axis, and the tip of an arm 44 projecting upward from the outer ring 43 in the radial direction is connected to the rear end of the piston cylinder 31 of the tool holder 17. . The boss sleeve 40 is locked from behind by a washer 45 interposed between the boss sleeve 40 and the second gear 39, and the boss sleeve 40 is moved backward by a stopper ring 47 pressed against the washer 45 by a coil spring 46 between the boss sleeve 40 and the second gear 39. Elastically regulated. A pair of recesses 48 are formed on the front surface of the boss sleeve 40 so as to be point-symmetric about the axis.

The clutch 41 is connected to a spline portion 49 formed on the intermediate shaft 18 so as to be integrally rotatable and slidable in the axial direction. When the outer periphery of the stop plate 23 is locked, the stop plate 23 moves forward and backward in cooperation with the tool holder 17. On the rear surface of the clutch 41, a pair of convex portions 51, 51 are formed point-symmetrically with respect to the axis, and engage with the concave portions 48, 48 of the boss sleeve 40 at the rearward sliding position (meshing position). And meshes with the boss sleeve 40 at the forward sliding position (non-meshing position).
Here, as shown in FIG. 3 (A), each convex portion 51 of the clutch 41 is formed in a reverse tapered shape in which the width in the rotation direction (circumferential direction) is wider at the distal end side than at the root side. The engagement surface 51a formed on the outer surface of the projection 51 is inclined outward. The inclination angle α is set in a range of, for example, 5 ° to 20 ° with respect to a straight line L parallel to the axis of the intermediate shaft 18 as viewed from the outside in the radial direction.

On the other hand, each concave portion 48 of the boss sleeve 40 is also formed in a reverse tapered shape in which the width in the rotation direction is narrower on the open side than on the bottom side, and the engagement surface 48a formed on the inner surface of the concave portion 48 is formed. Is inclined inward. The setting of the inclination angle α is the same as that of the protrusion 51 of the clutch 41.
However, on the front surface of the boss sleeve 40, since the convex portion 51 of the clutch 41 meshes forward from the left rotation direction (the direction of the arrow in FIG. 3A), the inside of each concave portion 48 on the opposite side of the meshing surface 48a. An escape portion 52 having a shallow (lower) side surface is formed.

  Thus, in a state where the clutch 41 is retracted and the boss sleeve 40 and the concave and convex portions 48 and 51 are engaged with each other, as shown in FIG. 3B, the engaging surface 51a of the convex portion 51 and the engaging surface 48a of the concave portion 48, as shown in FIG. Of the contact points at both front and rear ends, the tip side contact point P2 is displaced in the rotational direction toward the meshing side (lower side in the figure) with respect to the other side than the root side contact point (base end side contact point) P1. State. Conversely, in the meshing surface 48a of the concave portion 48, of the contact points at the front and rear ends of the convex portion 51 with the meshing surface 51a, the contact point on the open side (tip side) is smaller than the contact point P3 on the bottom side (base side contact point). The contact point P4 is shifted in the rotational direction to the side of meshing with the partner (upper side in the figure). In other words, the contact points P2 and P4 on the distal side are shifted to the meshing side with the partner in the rotation direction from the contact points P1 and P3 on the proximal side. At this time, the area between the root side contact point P1 and the tip side contact point P2 on the meshing surface 51a and the area between the bottom side contact point P3 and the open side contact point P4 on the meshing surface 48a are in contact with each other over the entire surface. Therefore, when the boss sleeve 40 and the clutch 41 are engaged with each other, the meshing surfaces 48a and 51a interfere with each other in the direction away from each other to generate resistance.

  On the other hand, a small diameter portion 53 having a smaller diameter than the spline portion 49 is formed in front of the spline portion 49 on the intermediate shaft 18, and a third gear 54 as a gear of the present invention is rotatably mounted on the small diameter portion 53. And the fourth gear 30 of the tool holder 17. The third gear 54 is engaged with a gear portion 55 as an engagement portion provided at the base of the small-diameter portion 53 at its inner periphery to be integrated with the intermediate shaft 18 in the rotation direction. 6 (a first state) and a forward position (a disengaged position (a second state) in FIG. 6) which is separated from the gear portion 55 and separate from the intermediate shaft 18 in the rotation direction. It is possible. A ring-shaped locking groove 56 is formed in the outer periphery of the third gear 54. An O-ring 57 is provided in front of the small-diameter portion 53 near the rear surface of the front bearing 37. The third gear 54 is externally mounted on the small-diameter portion 53, and the O-ring 57 is attached. It becomes a stop, and it is easy to assemble to the front housing 5.

  Reference numeral 58 denotes a slide plate as a slide member which is provided on the side of the intermediate shaft 18 and extends in the front-rear direction in a belt shape. As shown in FIGS. It has a locking piece 59 and is locked in the locking groove 56 of the third gear 54. An intermediate portion of the slide plate 58 is a folded portion 60 extending toward the intermediate shaft 18 in parallel with the locking piece 59, and the folded portion 60 and the locking piece 59 have a front bearing 37. A front end is inserted and connected to a boss 61 projecting into the front housing 5 on the side, and a guide shaft 62 projecting rearward in parallel with the intermediate shaft 18 penetrates. The guide shaft 62 is provided with a coil spring 63 as a biasing means whose front end is covered by the boss 61 and whose rear end is in contact with the locking piece 59.

  Therefore, the slide plate 58 is normally urged rearward, but its retreat is restricted at a position where it comes into contact with a stopper 64 (FIG. 4) provided on the outer periphery of the rear holding portion 13 of the inner housing 12. In this retracted position, the third gear 54, which has been retracted at the same time via the locking piece 59, is also in the retracted position in which it meshes with the gear portion 55. In the slide plate 58, an inverted L-shaped contact piece 65 is formed between the locking piece 59 and the folded portion 60, which extends upward and then bends rearward. The rearward bent portion of the contact piece 65 is located at a position overlapping the regulating plate 27 of the receiving plate 24 from the outside.

  Further, a lock member 66 is provided on the inner surface of the front side of the front housing 5 opposite to the guide shaft 62 with the intermediate shaft 18 interposed therebetween, as shown in FIGS. The lock member 66 is supported by a support pin 67 erected from the front housing 5 in parallel with the intermediate shaft 18, and has a locking claw 68, which engages with the third gear 54 at the advanced position on the intermediate shaft 18 side. 68 protruding. A positioning piece 69 protrudes from the side opposite to the locking claw 68, and the positioning piece 69 is guided by ribs 70, 70 provided on the front housing 5, thereby restricting the rotation of the lock member 66. . Further, the lock member 66 is urged to a retracted position where it abuts on the clip 72 at the tip of the support pin 67 by a coil spring 71 provided between the positioning piece 69 and the front housing 5. That is, the lock member 66, the support pin 67, and the coil spring 71 serve as rotation restricting means for restricting the rotation of the third gear 54 at the forward position.

  A mode switching lever 73 as a mode switching member is provided on a side surface of the front housing 5. As shown in FIG. 7, the mode switching lever 73 includes a disc-shaped rotating portion 75 rotatably fitted in a fitting hole 74 formed in the front housing 5, and an outer surface of the rotating portion 75 for rotating the front housing 5. The rotating part 75 includes a first and second eccentric pins 77 and 78 that are eccentric from the center of rotation and protrude toward the intermediate shaft 18. . The longer first eccentric pin 77 is located above the slide plate 58, from the rear of the contact piece 65 of the slide plate 58 and the rear of the regulating plate 27 of the receiving plate 24, over the two plates 58, 24, and inside the front housing 5. It has a length that protrudes into. The shorter second eccentric pin 78 also projects into the front housing 5 from above the slide plate 58 from behind the contact piece 65 and the regulating plate 27, but the tip interferes with the contact piece 65 in the front-rear direction. And the length does not interfere with the regulating plate 27. Here, the upper side of the movement locus of the second eccentric pin 78 overlaps with the extension of the tip of the contact piece 65.

  In the hammer drill 1 configured as described above, the first and second eccentric pins 77 and 78 are rotationally moved by gripping the knob 76 of the mode switching lever 73 and rotating the rotating unit 75 by 90 °. By performing the slide restriction on the receiving plate 24 and / or the slide plate 58 or canceling the restriction, three operation modes of a drill mode, a hammer drill mode, and a hammer mode can be selected. The knob 76 is provided with a lock button 80 that is protruded and urged by a coil spring 79. With the rotation of the mode switching lever 73, the pin 81 provided on the lock button 80 is attached to the outer surface of the front housing 5. It moves along the arcuate guide groove 82 provided. In the position of the corresponding operation mode, the pin 81 is locked by the locking portion 83 provided outside the guide groove 82 to maintain the operation mode. Hereinafter, each operation mode will be described.

First, at the rotation position of the mode switching lever 73 in which the knob 76 is tilted backward, as shown in FIG. 4, the first eccentric pin 77 rotates forward of the rotation center O of the rotation unit 75, and the second eccentric pin 78 rotates. The first eccentric pin 77 is located on the rear side of the center O, and is close to the rear edge of the regulating plate 27 of the receiving plate 24 in the forward position together with the tool holder 17. At this time, the slide plate 58 is at the retracted position where it comes into contact with the stopper portion 64 and the third gear 54 meshes with the gear portion 55.
Therefore, the retraction of the tool holder 17 is regulated by the first eccentric pin 77 via the regulating plate 27 of the receiving plate 24, the forward position where the clutch 41 is separated from the boss sleeve 40 is maintained, and the third gear 54 is moved to the intermediate shaft 18. It becomes the drill mode combined with.

  In this state, when the trigger 9 is pushed in to turn on the switch 8 to drive the brushless motor 3, the rotating shaft 4 rotates, and the intermediate shaft 18 is reduced and rotated from the second gear 39 via the first gear 11. . At this time, the clutch 41 and the third gear 54 rotate integrally, but since the clutch 41 does not mesh with the boss sleeve 40, the boss sleeve 40 does not rotate and the piston cylinder 31 does not operate. Therefore, the rotation of the third gear 54 is transmitted to the tool holder 17 via the fourth gear 30, and rotates the bit 35. Even if the bit 35 is pressed against the work material and the tool holder 17 is pushed in, the retraction of the receiving plate 27 is restricted, so that the drill mode is maintained.

Next, at the rotation position of the mode switching lever 73 in which the knob portion 76 is rotated upward by 90 °, the first eccentric pin 77 is located below the rotation center O of the rotation portion 75 as shown in FIG. The second eccentric pin 78 moves backward above the center of rotation O and comes close to the tip of the abutting piece 65 away from the regulating plate 27 of the receiving plate 24. The retracted position of the slide plate 58 does not change.
Therefore, the retraction of the tool holder 17 is not restricted by the first eccentric pin 77, and a hammer drill mode is provided in which the tool holder 17 can move to the retreat position together with the clutch 41. That is, when the tool holder 17 is pushed into the front housing 5 by pressing the bit 35 against the work material, the protrusions 51, 51 of the clutch 41 retracted together with the tool holder 17 mesh with the recesses 48, 48 of the boss sleeve 40, The rotation of the clutch 41 is transmitted to the boss sleeve 40. The meshing state between the third gear 54 and the fourth gear 30 does not change.
When the intermediate shaft 18 rotates in this state, the rotation of the clutch 41 is transmitted to the boss sleeve 40, and the arm 44 swings back and forth by the swash bearing 42 to move the piston cylinder 31 back and forth. Therefore, the striker 33 reciprocates interlockingly via the air chamber 32 and indirectly hits the bit 35 via the impact bolt 34. At the same time, the tool holder 17 rotates to rotate the bit 35.

  During use in the hammer drill mode, even if the pushing force of the bit 35 into the ground or the like is weakened and the pushing load of the tool holder 17 is reduced, as shown in FIG. Since the portions 51, 51 and the concave portions 48, 48 of the boss sleeve 40 generate resistance in the separating direction due to the contact of the mutually inclined engagement surfaces 51a, 48a, the tool holder 17 is pressed against the bias of the coil spring 25. Further, the advance of the clutch 41 is restricted, and the engagement between the clutch 41 and the boss sleeve 40 is maintained. Therefore, it is difficult for the hitting operation to be interrupted during the operation.

Next, at the rotation position of the mode switching lever 73 in which the knob 76 is rotated 90 ° in the forward direction, the first eccentric pin 77 is located behind the rotation center O as shown in FIG. Numeral 78 is located on the front side of the rotation center O, and moves the slide plate 58 to the forward position against the bias of the coil spring 63 via the contact piece 65 as shown in FIG.
Therefore, the retraction of the tool holder 17 is not restricted, and the tool holder 17 can be moved to the retreat position together with the clutch 41. However, the rotation of the intermediate shaft 18 is transmitted because the third gear 54 moved to the forward position together with the slide plate 58 is separated from the gear portion 55. Hammer mode is not performed. That is, when the intermediate shaft 18 rotates while the tool holder 17 is pushed in, the rotation of the clutch 41 is transmitted to the boss sleeve 40, the piston cylinder 31 is moved back and forth, the striker 33 is reciprocated, and the bit is passed through the impact bolt 34. While hitting 35, the third gear 54 separated from the gear portion 55 does not rotate, so that the tool holder 17 does not rotate.

Even in the hammer mode, even if the pressing load of the tool holder 17 is reduced, the convex portions 51, 51 of the clutch 41 and the concave portions 48, 48 of the boss sleeve 40 are inclined relative to each other as shown in FIG. The contact between the engaged surfaces 51a and 48a generates resistance in the separating direction. Accordingly, the engagement between the clutch 41 and the boss sleeve 40 is maintained, and the interruption of the striking operation is less likely to occur.
In addition, since the rotation of the third gear 54 is restricted by the locking claw 68 of the lock member 66 being locked at the forward position, the rotation of the tool holder 17 is also locked via the fourth gear 30. Therefore, when switching to the hammer mode, if the angle of the bit 35 such as a flap is set to an easy-to-use angle, the bit 35 can be locked and used as it is. If the locking claw 68 of the lock member 66 does not lock well when the third gear 54 advances, the lock member 66 is pushed forward against the bias of the coil spring 71. When the tool holder 17 is rotated via the third gear 54, the third gear 54 is rotated via the fourth gear 30, and the locking member 66 is returned to the forward position and locked at the position where the locking claw 68 is locked. .

Thus, according to the hammer drill 1 of the above-described embodiment, the third gear 54 is in the first state in which the rotation of the intermediate shaft 18 is transmitted (the engagement position with the intermediate shaft 18) and the rotation of the intermediate shaft 18 A mode switching lever 73 is provided so as to be switchable to a second state in which transmission is not performed (a non-engagement position with the intermediate shaft 18), and is capable of switching the state of the third gear 54 from outside the front housing 5. A hammer drill mode in which the state of the third gear 54 is switched by the mode switching lever 73 so that the third gear 54 rotates integrally with the intermediate shaft 18 to cause the tool holder 17 to rotate and the piston cylinder 31 to reciprocate; At least two operation modes, a hammer mode in which the third gear 54 is separated from the rotation of the intermediate shaft 18 and causes only the reciprocation of the piston cylinder 31, can be selected.
As a result, even with a small hammer drill 1 capable of selecting an operation mode depending on the front and rear positions of the tool holder 17 which is biased forward, the hammer mode can be selected, and further improvement in usability can be expected.
Further, the third gear 54 is slid between an engagement position where the third gear 54 engages with the intermediate shaft 18 to rotate integrally therewith and a non-engagement position where the engagement with the intermediate shaft 18 is released. The mode switching lever 73 is operated to switch the sliding position of the third gear 54 from outside the front housing 5 so that the intermediate shaft 18 can be switched between the state and the second state. The switching of the rotation transmission from the motor can be easily performed.

In particular, here, the mode switching lever 73 can switch the sliding position of the clutch 41 between a meshing position where the clutch 41 meshes with the boss sleeve 40 and rotates integrally, and a non-meshing position where the meshing with the boss sleeve 40 is released. By switching between the engagement position of the third gear 54 and the disengagement position of the clutch 41, a drill mode in which the third gear 54 rotates integrally with the intermediate shaft 18 and only the tool holder 17 rotates can be further selected. Therefore, three operation modes can be used, and the range of work can be expanded.
In addition, since the rotation restricting means (lock member 66, support pin 67, coil spring 71) for restricting the rotation of the third gear 54 at the non-engagement position of the third gear 54 is provided, the bit 35 in the hammer mode is provided. Can be locked, making it easier to perform filing work and the like.

Further, in the front housing 5, a guide shaft 62 supported in parallel with the intermediate shaft 18, a slide plate 58 engaged with the third gear 54 and movable back and forth along the guide shaft 62, and a slide plate 58 are provided. A coil spring 63 is provided for urging the third gear 54 toward the engagement position, and the third gear 54 is moved by the slide plate 58 moving in the counter-biasing direction of the coil spring 63 with the switching operation of the mode switching lever 73. By sliding to the non-engaging position, the sliding position of the third gear 54 can be switched smoothly.
In addition, the mode switching lever 73 is provided with two first and second eccentric pins 77 and 78 to be rotated, and the second eccentric pin 78 moves the slide plate 58 in the counter-biasing direction with the rotation. Since it is moved, the hammer mode can be selected by operating one mode switching lever 73.

At the front end of the intermediate shaft 18, a small-diameter portion 53 having a smaller diameter than the installation side of the boss sleeve 40 is formed, and the third gear 54 is provided on the small-diameter portion 53, and provided at the root of the small-diameter portion 53 at the engagement position. Since the third gear 54 is engaged with the gear portion 55 and is rotated integrally with the intermediate shaft 18, the third gear 54 can be reduced in size and space can be saved.
The brushless motor 3 is disposed below the intermediate shaft 18 in the main body housing 2 so that the axis of the rotating shaft 4 intersects the intermediate shaft 18, and the handle 7 is provided behind the tool holder 17. Thus, the dimension in the front-rear direction can be made compact, and the pushing load can be applied without loss by the handle 7 provided directly behind the tool holder 17.

In the invention in which the hammer mode can be selected, the structures of the receiving plate, the slide plate, and the rotation restricting means are not limited to the above-described embodiments. It can be changed as appropriate, for example, by guiding with a rib or the like provided on the inner surface of the device. The rotation restricting means may be omitted.
Further, in the above-described embodiment, the striking operation can be selected by engaging and disengaging the clutch with a conversion member such as a boss sleeve. However, there is no clutch, and the conversion member rotates integrally with the intermediate shaft. By switching the slide position of the gear for use, a hammer drill capable of selecting two operation modes, a hammer mode and a hammer drill mode, may be used.
Further, in the above embodiment, the rotation transmission from the intermediate shaft is switched by sliding the gear (third gear). However, the gear is provided in a free rotation state with respect to the intermediate shaft without sliding, and the intermediate shaft is not rotated. It is also possible to provide a clutch member that is integrally rotatable and slidable in the axial direction, and to switch the rotation transmission from the intermediate shaft by engaging and disengaging the clutch member with the gear by the mode switching member. is there.

On the other hand, according to the hammer drill 1 of the above embodiment, the mutually meshing surfaces 51a, 48a with the convex portion 51 and the concave portion 48 are closer to the mating surfaces of the mating side on the side closer to themselves than the base end side contact points P1, P3. Also, the tip side contact points P2 and P4, which are in contact with the mating surface of the partner on the side farther from itself, include shapes that are shifted to the mating side with the partner in the rotation direction, respectively, and the convex portion 51 and the concave portion 48 In the meshing state, the interference between the meshing surfaces 51a and 48a causes a resistance in the separating direction between the boss sleeve 40 and the clutch 41.
Thus, even if the retracted clutch 41 is engaged with the boss sleeve 40 together with the tool holder 17 that is biased forward, the hammer drill mode or the hammer mode can be selected. 41 is less likely to be disengaged, and good workability can be maintained.

Particularly, in this case, when the convex portion 51 and the concave portion 48 are engaged with each other, the entire surfaces between the proximal contact point P1 (P3) and the distal contact point P2 (P4) on the mutual engaging surfaces 51a and 48a are mutually connected. Since they are in contact with each other, interference between the meshing surfaces 51a and 48a in the separating direction increases, and the engagement of the clutch 41 is more difficult to be disengaged.
In addition, the convex portion 51 has a reverse tapered shape in which the tip side is wider in the rotational direction than the root side and the inclined outer surface becomes the meshing surface 51a, and the concave portion 48 is more open than the bottom side. Since the side has a reverse tapered shape in which the width in the rotation direction is formed to be narrower and the inclined inner surface becomes the meshing surface 48a, the meshing surfaces 51a, 48a which are hard to be disengaged can be easily formed.

Further, since the inclination angles of both the engagement surfaces 51a and 48a of the convex portion 51 and the concave portion 48 are within a range of 5 ° to 20 ° with respect to the straight line L parallel to the axis of the intermediate shaft 18, the engagement is easy to be easily performed and the engagement is difficult. The surfaces 51a and 48a can be set.
In addition, on the end surface of the boss sleeve 40 where the concave portion 48 is formed, a relief portion 52 is formed in which the inner surface opposite to the engaging surface 48a with the convex portion 51 becomes shallower than the engaging surface 48a. The projections 51 easily enter the recesses 48, and the meshing is smoothly performed.

In the invention relating to the shapes of the projections and the recesses, the number of the projections and depressions is not limited to the above-described embodiment, and three or more may be provided. It may be inclined.
Further, in the above embodiment, the meshing surface of the uneven portion is an inclined plane, but one meshing surface of the uneven portion is a convex curved surface that swells in an arc shape, and the other meshing surface is a concave curved surface to which the swelling portion fits. You can also.
Furthermore, it is not necessary to make the entire surface of the meshing surface an inclined plane or a curved surface.For example, in the convex portion, the root side has the same width, the tip side has an inverse taper, and the corresponding concave portion has a reverse taper on the bottom side, It is also conceivable to make the open side the same width. That is, a meshing surface that causes interference in the separating direction may be formed on a part of the side surface of the uneven portion. Therefore, even if the convex portion and the concave portion that fits into the convex portion in which the root side half becomes an inclined plane or curved surface and the distal side half becomes tapered, the root side of the convex portion is separated from the open side of the concave portion. Interference will occur in the direction.

  In the above-described embodiment, the third gear is slid so that the hammer mode can be selected. However, the third gear does not slide, and the two modes of the drill mode and the hammer drill mode are performed by moving the tool holder and the clutch back and forth. The present invention relating to the shape of the convex portion and the concave portion can be adopted even with another impact tool such as a hammer drill in which only the operation mode can be selected.

  1. Hammer drill, 2. Body housing, 3. Brushless motor, 4. Rotary shaft, 5. Front housing, 6. Output section, 7. Handle, 11. First gear, 12. Inner housing, 17 tool holder, 18 intermediate shaft, 23 locking plate, 24 receiving plate, 25 coil spring, 27 restricting plate, 30 fourth gear, 31 piston Cylinder, 33 striker, 35 bit, 39 second gear, 40 boss sleeve, 41 clutch, 48 recess, 48a, 51a engagement surface, 49 spline portion, 51 .. convex part, 52, relief part, 53, small diameter part, 54, third gear, 55, gear part, 58, slide plate, 59, locking piece, 62, guide shaft, 65 ..Abutment pieces, 66..Locks Material, 67 support pin, 73 mode switching lever, 75 rotating part, 76 knob part, 77 first eccentric pin, 78 second eccentric pin, P1 root contact point , P2... Tip side contact point, P3... Bottom side contact point, P4.

Claims (4)

A housing for housing the motor;
A tool holder capable of holding a tip tool, being movable back and forth in the housing, and being provided so as to protrude forward;
A striking member provided to be movable back and forth into the tool holder;
An intermediate shaft provided in the housing in parallel with the tool holder, to which rotation of the motor is transmitted;
A conversion member provided on the intermediate shaft, for converting rotation of the intermediate shaft into reciprocating motion of the striking member,
A clutch that is provided so as to be integrally rotatable with the intermediate shaft and slidable in the axial direction, moves forward and backward in cooperation with the tool holder, and engages with the conversion member at a predetermined retreat position. The engagement with the clutch, a striking tool made by engaging in the rotational direction of the convex portion provided in any one, and the concave portion provided in the other,
The protruding portion and the concave portion have a meshing surface with each other that is closer to the mating surface of the mating side on the side closer to the base end than the contact point on the mating side of the mating side. Each of the contact points includes a shape that is shifted toward the meshing side with the partner in the rotation direction,
In the meshing state of the convex portion and the concave portion, while causing resistance in the separating direction between the conversion member and the clutch due to interference between the meshing surfaces of each other,
A striking tool characterized in that a relief portion is formed on an end surface where the concave portion is formed so that an inner side surface of the concave portion opposite to the meshing surface is shallower than an inner side surface of the meshing surface side .   The method according to claim 1, wherein in the meshing state between the convex portion and the concave portion, the entire surfaces between the base side contact point and the distal side contact point in the meshing surfaces are in contact with each other. The described impact tool.   The convex portion has a reverse tapered shape in which the width of the tip side is wider in the rotational direction than the root side and the inclined outer surface is the meshing surface, and the concave portion is closer to the open side than the bottom side. The impact tool according to claim 1, wherein the inner surface that is formed to have a smaller width in the rotational direction and has an inclined inner surface has an inverted tapered shape that is the meshing surface.   The impact according to claim 3, wherein an inclination angle of both the engagement surfaces of the convex portion and the concave portion is in a range of 5 ° to 20 ° with respect to a straight line parallel to the axis of the intermediate shaft. tool.

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