JP2017154229A - Hammer drill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further improve usability in a hammer drill in which an operation mode is selectable by the front/rear position of a tool holder projected and pressed forward.SOLUTION: In a hammer drill 1, a third gear 54 that rotates a tool holder 17 is slidably provided between an engagement position so as to be engaged with a gear part 55 of an intermediate shaft 18 and a disengagement position so as to be disengaged from the center shaft 18. A mode switch lever 73 is provided, which is able to switch the slide position of the third gear 54. By switching the slid position of the third gear 54 by the mode switch lever 73, at least two operation modes are selectable, which are hammer drill mode in which the third gear 54 is rotated integrally with the intermediate shaft 18, thereby causing the tool holder 17 to rotate and reciprocate the piston cylinder 31, and a hammer mode in which the third gear 54 is disconnected from rotation of the intermediate shaft 18, thereby causing only reciprocation of the piston cylinder 31.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a hammer drill in which a tool holder for holding a tip tool is provided in a housing so as to be movable back and forth and urged forward, and an operation mode can be selected depending on the front and back position of the tool holder.

  As disclosed in Patent Document 1, a hammer holder is provided with a tool holder for holding a tip tool such as a drill bit that can be moved back and forth in the housing and urged forward, and the motor rotates in the housing. The intermediate shaft to be transmitted is provided in parallel with the tool holder, and the rotation of the intermediate shaft is converted into the reciprocating motion of a striking member such as a piston cylinder accommodated in the tool holder. There has been known one provided with a conversion member that performs the above and a clutch that engages and disengages the conversion member in association with the forward and backward movement of the tool holder. 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 operating the mode switching member, and the retraction of the tool holder is a position where the clutch engages with the conversion member. The hammer drill mode can be selected by allowing up to.

Japanese Patent No. 4746920

  In such a small hammer drill, the gear provided on the intermediate shaft and the gear provided on the tool holder are always in mesh, so the drill mode and hammer drill mode can be selected as the operation mode, and the hammer mode is also selected. There was a need for ease of use like a large hammer drill.

  Therefore, the present invention aims to provide a hammer drill that can be expected to further improve the usability even if the operation mode can be selected depending on the front and rear positions of the tool holder that is biased to protrude forward. is there.

To achieve the above object, the invention described in claim 1 includes a housing that houses a motor, a tool holder that can hold a tip tool, can be moved back and forth in the housing, and is urged to protrude forward. A striking member provided in the tool holder so as to be movable back and forth, an intermediate shaft provided in parallel with the tool holder in the housing, and provided in the intermediate shaft, and provided in the intermediate shaft. A hammer drill comprising: a transmission gear; and a conversion member that is provided on the intermediate shaft and converts the rotation of the intermediate shaft into a reciprocating motion of the striking member,
A mode in which the gear can be switched between a first state where the rotation of the intermediate shaft is transmitted and a second state where the rotation of the intermediate shaft is not transmitted, and the gear state can be switched from the outside of the housing A switching member is provided, and by changing the state of the gear by the mode switching member, the gear rotates integrally with the intermediate shaft to cause the tool holder to rotate and the reciprocating motion of the striking member; and the gear of the intermediate shaft It is characterized in that at least two operation modes, which are separated from rotation and a hammer mode in which only the reciprocation of the striking member is generated, can be selected.
According to a second aspect of the present invention, in the configuration of the first aspect, the gear includes an engagement position where the gear engages with the intermediate shaft and rotates integrally, and a non-engagement position where the engagement with the intermediate shaft is released. It is possible to switch between the first state and the second state by sliding between them, and the mode switching member is characterized in that the sliding position of the gear is switched from the outside of the housing.
According to a third aspect of the present invention, in the configuration of the second aspect of the present invention, the intermediate shaft is integrally rotatable and slidable in the axial direction. The mode switching member is capable of switching the sliding position of the clutch between a meshing position that meshes with the conversion member and rotates integrally, and a non-meshing position where the meshing with the conversion member is released. By switching between the engagement position and the clutch non-engagement position, it is possible to further select a drill mode in which the gear rotates integrally with the intermediate shaft and causes only the tool holder to rotate.
According to a fourth aspect of the present invention, in the configuration of the second or third aspect, a rotation restricting means for restricting the rotation of the gear at the non-engagement position of the gear is provided.
According to a fifth aspect of the present invention, in the structure of any one of the second to fourth aspects, the guide shaft is supported in the housing in parallel with the intermediate shaft, and is moved forward and backward along the guide shaft while being locked to the gear. And a biasing means for biasing the slide member to the gear engagement position, and the slide member moves in a counter biasing direction of the biasing means in accordance with the switching operation of the mode switching member. Thus, the gear slides to the non-engagement position.
According to a sixth aspect of the present invention, in the configuration of the fifth aspect, the mode switching member is provided with two eccentric pins for rotational operation, and one eccentric pin repels the slide member in accordance with the rotational operation. It is characterized by moving in the direction of force.
According to a seventh aspect of the present invention, in the configuration of any one of the second to sixth aspects, a small-diameter portion having a smaller diameter than the installation side of the conversion member is formed at the end of the intermediate shaft, and the gear has a small-diameter portion. And is engaged with an engaging portion provided at the base of the small-diameter portion at the engaging position to rotate integrally with the intermediate shaft.
The invention according to claim 8 is the structure according to any one of claims 1 to 7, wherein the motor is disposed below the intermediate shaft in the housing in a direction in which the axis of the rotary shaft intersects the intermediate shaft. A handle is provided behind the tool holder.

According to the first aspect of the present invention, the hammer mode can be selected even for a small hammer drill that allows the operation mode to be selected depending on the front and rear positions of the tool holder that is biased forward and urged, and the usability can be further improved. I can expect.
According to the second aspect of the present invention, in addition to the effect of the first aspect, the rotation transmission from the intermediate shaft can be easily switched by the sliding of the gear.
According to the third aspect of the invention, in addition to the effect of the second aspect, the drill mode can be further selected, so that three operation modes can be used, and the range of work is widened.
According to the fourth aspect of the invention, in addition to the effect of the second or third aspect, by adopting the rotation restricting means, the rotation of the tip tool in the hammer mode can be locked, and the chipping work or the like is facilitated.
According to the fifth aspect of the invention, in addition to the effect of any of the second to fourth aspects, the gear is slid through the slide member, so that the gear slide position can be switched smoothly.
According to the sixth aspect of the invention, in addition to the effect of the fifth aspect, since the slide member is moved by the eccentric pin provided on the mode switching member, the hammer mode can be selected by operating one mode switching member. .
According to the invention described in claim 7, in addition to the effect of any one of claims 2 to 6, the gear can be reduced in size by saving the space by providing the gear in the small diameter portion provided in the intermediate shaft. Connected.
According to the eighth aspect of the present invention, in addition to the effect of any one of the first to seventh aspects, the size in the front-rear direction can be reduced by the arrangement of the motor and the handle, and the handle provided immediately behind the tool holder can be used. Push load can be applied without loss.

It is a general view of a hammer drill (drill mode). It is a general view of a hammer drill (hammer drill mode). It is explanatory drawing of the meshing part of a clutch and a boss | hub sleeve, (A) is before meshing, (B) shows a meshing state, respectively. It is explanatory drawing of drill mode, (A) shows the switching position of a mode switching lever, (B) shows the inside of a front housing, respectively. It is explanatory drawing of hammer drill mode, (A) shows the switching position of a mode switching lever, (B) shows the inside of a front housing, respectively. It is explanatory drawing of hammer mode, (A) shows the switching position of a mode switching lever, (B) shows the inside of a front housing, respectively. It is the sectional view on the AA line of FIG. It is the BB sectional view taken on the line of FIG. It is explanatory drawing which shows the positional relationship of the slide plate and mode switching lever in 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 that is also a striking tool, and the inside of the main body housing is omitted except for a brushless motor and a switch. The hammer drill 1 has a tapered cylindrical front housing 5 that accommodates the output portion 6 protruding forward on the front side (left side in FIG. 1) of the main body housing 2 that accommodates the brushless motor 3 and a controller (not shown). A handle 7 for receiving a switch 8 having a trigger 9 is provided at a position on the upper rear side of the main body housing 2 and directly behind a tool holder 17 described later. Reference numeral 10 denotes a battery pack that is attached to the lower rear portion of the main body housing 2 and serves as a power source.
The brushless motor 3 is accommodated in the main body housing 2 in an inclined posture with the rotary shaft 4 facing upward and obliquely rearward, and a first gear (bevel gear) 11 provided at the tip of the rotary shaft 4 is placed in the front housing 5. Protruding.

An inner housing 12 is held inside the front housing 5. The inner housing 12 includes an oval-shaped rear holding portion 13 that is fitted to the rear end of the front housing 5 and is assembled with the main body housing 2, and a support portion 14 that protrudes forward from the holding portion 13. The ring-shaped front holding portion 15 is screwed to the front end of the support portion 14. The first gear 11 of the rotating shaft 4 is pivotally supported by a bearing 16 held by the rear holding portion 13 and protrudes into the front housing 5.
A cylindrical tool holder 17 and an intermediate shaft 18 positioned immediately below the cylindrical 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 pivotally supported by a bearing 19 provided at the front portion of the front housing 5 and a metal bearing 20 press-fitted into the front holding portion 15 of the inner housing 12 so as to be rotatable and movable back and forth.

  A flange 21 is formed on the outer periphery of the rear portion of the tool holder 17, and the rear of the flange 21 is covered with a locking plate 23 and a receiving plate 24 with a washer 22 therebetween. The tool holder 17 is normally urged to protrude to a forward position where a retaining ring 26 provided on the outer periphery of the front part comes into contact with the bearing 19 by a coil spring 25 which is externally provided between the receiving plate 24 and the front holding part 15. The retraction of the tool holder 17 is regulated at the position of FIG. 2 where the receiving plate 24 contacts the metal bearing 20. On the lower side of the receiving plate 24, as shown in FIG. 4, a regulating plate 27 is formed integrally with the side view in an inverted L shape.

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

  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 ( Bevel gear) 39 is engaged with the first gear 11 of the rotating shaft 4. The intermediate shaft 18 in front of the second gear 39 is externally provided with a boss sleeve 40 as a conversion member that can rotate separately from the intermediate shaft 18 and a clutch 41 that rotates integrally with the intermediate shaft 18. . The boss sleeve 40 has a swash bearing 42 inclined from the axis, and the tip of an arm 44 projecting radially outward from the outer ring 43 is connected to the rear end of the piston cylinder 31 of the tool holder 17. . The boss sleeve 40 is locked to a washer 45 interposed between the second gear 39 from behind and a stopper ring 47 pressed against the washer 45 by a coil spring 46 between the second gear 39 and the reverse position thereof. It is elastically regulated. In addition, a pair of concave portions 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 coupled to a spline portion 49 formed on the intermediate shaft 18 so as to rotate integrally and slide in the axial direction. The clutch 41 is provided in the groove 50 provided on the outer periphery of the front end. When the outer periphery of the stop plate 23 is locked, it moves back and forth in conjunction with the tool holder 17. On the rear surface of the clutch 41, a pair of convex portions 51, 51 are formed point-symmetrically about the axis, and are fitted into the concave portions 48, 48 of the boss sleeve 40 at the rearward sliding position (meshing position). The boss sleeve 40 is engaged, and the engagement with the boss sleeve 40 is released at the forward slide position (non-engagement position).
Here, as shown in FIG. 3A, 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 on the tip side than on the root side. The meshing surface 51a formed on the outer surface of the convex portion 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 when 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 taper shape in which the width in the rotation direction is narrower on the open side than on the bottom side, and the meshing surface 48a formed on the inner surface of the concave portion 48. Is tilted inward. The setting of the inclination angle α is the same as that of the convex portion 51 of the clutch 41.
However, on the front surface of the boss sleeve 40, the convex portion 51 of the clutch 41 meshes forward from the left rotation direction (the arrow direction in FIG. 3A), so that the inner side of each concave portion 48 on the opposite side of the meshing surface 48a. A relief portion 52 whose side surface becomes shallower (lowered) is formed.

  As a result, when the clutch 41 is retracted and engaged with the boss sleeve 40 and the concavo-convex portions 48, 51, as shown in FIG. 3B, the engaging surface 51a of the convex portion 51 is engaged with the engaging surface 48a of the concave portion 48. Of the contact points at both the front and rear ends, the tip side contact point P2 is shifted toward the mating side (the lower side in the figure) in the rotational direction rather than the root side contact point (base end side contact point) P1. It becomes a state. On the contrary, in the meshing surface 48a of the concave portion 48, among the contact points at both the front and rear ends with the meshing surface 51a of the convex portion 51, the contact point on the open side (front end side) rather than the bottom side contact point (base end side contact point) P3. The contact point (P4) is shifted to the meshing side (upper side in the figure) with the other party in the rotational direction. That is, the distal side contact points P2 and P4 are shifted from the proximal side contact points P1 and P3 toward the other side in the rotational direction. At this time, between the root side contact point P1 and the tip side contact point P2 on the meshing surface 51a and 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, the meshing surfaces 48a and 51a interfere with each other in the direction away from each other to cause 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 in 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. , Meshing with the fourth gear 30 of the tool holder 17. The third gear 54 is engaged with a gear portion 55 as an engaging portion provided at the base of the small-diameter portion 53 so that its inner periphery meshes with the intermediate shaft 18 in the rotation direction (engaged in FIGS. 1 and 2). Position (first state)) and forward / backward movement between the intermediate shaft 18 and the forward movement position (non-engagement position (second state)) in FIG. It is possible. A ring-shaped locking groove 56 is recessed on the outer periphery of the third gear 54. Reference numeral 57 denotes an O-ring that is externally attached to the front of the small-diameter portion 53 at the rear surface of the front bearing 37. The third gear 54 is externally attached to the small-diameter portion 53, and the O-ring 57 is attached. It becomes a stop and becomes easy to assemble to the front housing 5.

  Reference numeral 58 denotes a slide plate as a slide member provided on the side of the intermediate shaft 18 and extending in a strip shape in the front-rear direction. As shown in FIGS. 7 and 8, the front end is bent at a right angle toward the intermediate shaft 18 side. A locking piece 59 is provided and locked in the locking groove 56 of the third gear 54. An intermediate portion of the slide plate 58 is a folded portion 60 that extends in parallel to the locking piece 59 toward the intermediate shaft 18, and the folded portion 60 and the locking piece 59 are connected to the front bearing 37. A guide shaft 62 that protrudes rearward in parallel with the intermediate shaft 18 passes through the front end of the boss 61 that protrudes into the front housing 5 from the side. The guide shaft 62 is provided with a coil spring 63 as an urging means whose front end is covered with the boss 61 and whose rear end is in contact with the locking piece 59.

  Therefore, although the slide plate 58 is normally urged rearward, the backward movement is restricted at a position where the slide plate 58 contacts the stopper portion 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 retracted simultaneously via the locking piece 59 is also in the retracted position where it meshes with the gear portion 55. In the slide plate 58, an inverted L-shaped contact piece 65 that extends upward and then bends backward is formed between the locking piece 59 and the folded portion 60. The rearward bent portion of the contact piece 65 is positioned so as to overlap the regulating plate 27 of the receiving plate 24 from the outside.

  Further, a lock member 66 is provided on the front inner surface of the front housing 5 on the opposite side of the intermediate shaft 18 from the guide shaft 62 as shown in FIGS. The locking member 66 is supported by a support pin 67 extending in parallel with the intermediate shaft 18 from the front housing 5, and on the intermediate shaft 18 side, locking claws 68 that mesh with the third gear 54 in the forward movement position. 68 is provided. A positioning piece 69 protrudes on the opposite side of the locking claw 68, and the positioning piece 69 is guided by ribs 70, 70 provided on the front housing 5, whereby the rotation of the lock member 66 is restricted. . Further, the lock member 66 is biased 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 movement position.

  A mode switching lever 73 as a mode switching member is provided on the side surface of the front housing 5. As shown in FIG. 7, the mode switching lever 73 includes a disc-shaped rotating portion 75 that is rotatably fitted in a fitting hole 74 formed in the front housing 5, and an outer surface of the rotating portion 75. The rotary portion 75 includes a first eccentric pin 77 and a second eccentric pin 78 that are eccentric from the rotation center and project toward the intermediate shaft 18 side. . Among these, the longer first eccentric pin 77 is located above the slide plate 58 and beyond the plates 58 and 24 from the rear side of the contact piece 65 of the slide plate 58 and the regulating plate 27 of the receiving plate 24 in the front housing 5. It has a length that projects. The shorter second eccentric pin 78 also projects into the front housing 5 from behind the contact piece 65 and the restriction plate 27 above the slide plate 58, but the tip is a position where it interferes with the contact piece 65 in the front-rear direction. However, the length does not interfere with the restriction plate 27. Here, the upper side of the movement locus of the second eccentric pin 78 overlaps the extended line 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 rotated and moved by gripping the knob portion 76 of the mode switching lever 73 and rotating the rotating portion 75 by 90 °. By restricting or releasing the slide with respect to the receiving plate 24 and / or the slide plate 58, three operation modes of a drill mode, a hammer drill mode, and a hammer mode can be selected. The knob portion 76 is provided with a lock button 80 that is projected and urged by a coil spring 79, and a pin 81 provided on the lock button 80 on the outer surface of the front housing 5 as the mode switching lever 73 rotates. It moves along the provided arcuate guide groove 82. At the position of the corresponding operation mode, the pin 81 is engaged with the engagement portion 83 provided outside the guide groove 82, and the operation mode is maintained. Hereinafter, each operation mode will be described.

First, at the rotational position of the mode switching lever 73 in which the knob portion 76 is tilted backward, as shown in FIG. 4, the first eccentric pin 77 is in front of the rotational center O of the rotating portion 75, and the second eccentric pin 78 is rotated. The first eccentric pin 77 is located behind the center O, and is close to the rear edge of the restricting plate 27 of the receiving plate 24 in the advanced position together with the tool holder 17. At this time, the slide plate 58 is in a retracted position where it abuts against the stopper portion 64 and engages the third gear 54 with the gear portion 55.
Therefore, the backward movement 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 movement 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 a drill mode combined with.

  In this state, when the trigger 9 is pushed in to turn on the switch 8 and drive the brushless motor 3, the rotating shaft 4 rotates, and the intermediate shaft 18 is decelerated 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. However, 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 the bit 35 is rotated. Even if the bit holder 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, in the rotational position of the mode switching lever 73 in which the knob portion 76 is rotated 90 ° upward, the first eccentric pin 77 is positioned below the rotational center O of the rotational portion 75 as shown in FIG. The second eccentric pin 78 moves rearward from the restricting plate 27 of the receiving plate 24 and moves close to the tip of the contact piece 65 by moving to the upper side of the rotation center O. The retracted position of the slide plate 58 does not change.
Therefore, the tool holder 17 is not regulated by the first eccentric pin 77, and the hammer drill mode is enabled in which the tool holder 17 can move to the retracted position together with the clutch 41. That is, when the bit 35 is pressed against the work material and the tool holder 17 is pushed into the front housing 5, the convex portions 51 and 51 of the clutch 41 retracted together with the tool holder 17 mesh with the concave portions 48 and 48 of the boss sleeve 40, The rotation of the clutch 41 is transmitted to the boss sleeve 40. The meshing state of 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 through the air chamber 32 and indirectly hits the bit 35 through the impact bolt 34. At the same time, the tool holder 17 rotates to rotate the bit 35.

  Even when the push force of the bit holder 35 to the ground or the like is weakened and the push load of the tool holder 17 is reduced when used in this hammer drill mode, the convexity of the clutch 41 as shown in FIG. Since the portions 51 and 51 and the recesses 48 and 48 of the boss sleeve 40 have resistance in the separating direction due to contact between the meshing surfaces 51 a and 48 a inclined to each other, the tool holder 17 resists the bias of the coil spring 25. Further, the forward movement of the clutch 41 is restricted, and the engagement between the clutch 41 and the boss sleeve 40 is maintained. Therefore, the hitting operation is less likely to be interrupted during the work.

Next, at the rotational position of the mode switching lever 73 in which the knob portion 76 is rotated 90 ° forward, as shown in FIG. 6, the first eccentric pin 77 is located on the rear side of the rotation center O, and the second eccentric pin 78 is located on the front side of the rotation center O, and moves the slide plate 58 to the forward movement position against the bias of the coil spring 63 via the contact piece 65 as shown in FIG.
Accordingly, the retraction of the tool holder 17 is not restricted and can move to the retreat position together with the clutch 41, but the third gear 54 that has moved to the advance position together with the slide plate 58 is separated from the gear portion 55, so that the rotation of the intermediate shaft 18 is transmitted. It becomes a hammer mode that is not. 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, and the striker 33 is reciprocated. The tool holder 17 does not rotate because the third gear 54 away from the gear portion 55 does not rotate.

Even in this hammer mode, even if the pressing load of the tool holder 17 may decrease, the convex portions 51 and 51 of the clutch 41 and the concave portions 48 and 48 of the boss sleeve 40 are inclined with respect to each other as shown in FIG. Resistance is generated in the separation direction by the contact between the meshing surfaces 51a and 48a. Therefore, the engagement between the clutch 41 and the boss sleeve 40 is maintained, and the hitting operation is hardly interrupted.
The rotation of the tool holder 17 is also locked via the fourth gear 30 because the rotation of the third gear 54 is restricted when the locking claw 68 of the lock member 66 is locked at the forward movement position. Therefore, if the angle of the bit 35 such as the chisel is set to an easy-to-use angle when switching to the hammer mode, it can be locked and used as it is. When the third gear 54 moves forward, if the locking claw 68 of the lock member 66 does not lock well, the lock member 66 is pushed forward against the bias of the coil spring 71, but the bit 35 If the tool holder 17 is rotated through the third gear 54, the third gear 54 is rotated through the fourth gear 30, and the lock member 66 is returned to the forward movement position and locked at the position where the locking claw 68 is locked. .

Thus, according to the hammer drill 1 of the said form, when the 3rd gear 54 is the 1st state (engagement position with the intermediate shaft 18) to which rotation of the intermediate shaft 18 is transmitted, rotation of the intermediate shaft 18 is carried out. A mode switching lever 73 is provided which can be switched to a second state where the transmission is not performed (a non-engagement position with the intermediate shaft 18) and which can switch the state of the third gear 54 from the outside of the front housing 5. Then, by switching the state of the third gear 54 by the mode switching lever 73, the hammer drill mode in which the third gear 54 rotates integrally with the intermediate shaft 18 to cause the tool holder 17 to rotate and to reciprocate the piston cylinder 31, At least two operation modes can be selected: 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.
Thereby, even if it is a small hammer drill 1 which can select an operation mode by the front-and-rear position of the tool holder 17 projected and urged | biased forward, a hammer mode can be selected and the further improvement of usability can be anticipated.
Further, the first gear 54 is slid between an engagement position where the third gear 54 is engaged with the intermediate shaft 18 and integrally rotated 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 slide position of the third gear 54 from the outside of the front housing 5 so that it can be switched between the state and the second state. It is possible to easily switch the rotation transmission from.

In particular, here, the mode switching lever 73 can switch the sliding position of the clutch 41 between a meshing position that meshes with the boss sleeve 40 and rotates integrally and a non-meshing position where the meshing with the boss sleeve 40 is released. Further, a drill mode in which the third gear 54 rotates together with the intermediate shaft 18 and causes only rotation in the tool holder 17 by switching between the engagement position of the third gear 54 and the non-engagement position of the clutch 41 can be further selected. Therefore, three operation modes can be used, and the range of work is expanded.
Further, by providing 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, the bit 35 in the hammer mode is provided. The rotation of the can be locked, and it is easy to perform the chiseling work.

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

A small-diameter portion 53 having a smaller diameter than the installation side of the boss sleeve 40 is formed at the front end of the intermediate shaft 18 so that the third gear 54 is externally mounted on the small-diameter portion 53 and provided at the root of the small-diameter portion 53 at the engagement position. The third gear 54 can be miniaturized and the space can be saved because it is engaged with the gear portion 55 and rotated integrally with the intermediate shaft 18.
The brushless motor 3 is disposed below the intermediate shaft 18 in the main body housing 2 so that the axis of the rotary shaft 4 intersects the intermediate shaft 18, and a handle 7 is provided behind the tool holder 17. As a result, the dimensions in the front-rear direction can be reduced, and the pushing load can be applied without loss by the handle 7 provided immediately behind the tool holder 17.

In the invention enabling the selection of the hammer mode, the structure of the receiving plate, the slide plate, and the rotation restricting means is not limited to the above form, and the shape of the restricting plate and the contact piece is changed, or the slide plate is not a guide shaft but a housing. It can be changed as appropriate, for example, by being guided by a rib provided on the inner surface. The rotation restricting means can be omitted.
Further, in the above embodiment, the clutch is engaged with and disengaged from the conversion member such as the boss sleeve so that the hitting operation can be selected. However, there is no clutch, the conversion member rotates integrally with the intermediate shaft, and the rotation transmission is performed. A hammer drill that can select two operation modes, a hammer mode and a hammer drill mode, by switching the sliding position of the gear for use 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 intermediate shaft is provided in a rotation free state with respect to the intermediate shaft without sliding the gear. It is also possible to provide a clutch member that can rotate integrally and slide in the axial direction, and this clutch member can be engaged with and disengaged from the gear by the mode switching member to switch the rotation transmission from the intermediate shaft. is there.

On the other hand, according to the hammer drill 1 of the said form, the mutual meshing surfaces 51a and 48a with the convex part 51 and the recessed part 48 are from the base end side contact points P1 and P3 which contact the other meshing surface in the near side. However, the tip side contact points P2 and P4 that come into contact with the mating surface on the far side from each other include shapes that shift to the meshing side with the mating member in the rotational direction. In this meshing state, resistance between the boss sleeve 40 and the clutch 41 in the separating direction is generated by interference between the meshing surfaces 51a and 48a.
As a result, even if the clutch 41 retracted together with the tool holder 17 protruding and biased forward is engaged with the boss sleeve 40, the hammer drill mode or the hammer mode can be selected. 41 becomes difficult to disengage, and good workability can be maintained.

In particular, here, in the meshed state of the convex portion 51 and the concave portion 48, the entire surfaces between the proximal contact point P1 (P3) and the distal contact point P2 (P4) on the mutual meshing surfaces 51a, 48a are mutually Since they are in contact with each other, the interference between the meshing surfaces 51a and 48a in the separation direction increases, and the engagement of the clutch 41 is more difficult to disengage.
Further, the convex portion 51 has a reverse taper shape in which the width on the tip side is wider than the base side in the rotation direction and the inclined outer surface becomes the meshing surface 51a, and the concave portion 48 is opened more than the bottom side. Since the side is formed with a narrower width in the rotation direction and the inclined inner surface becomes the meshing surface 48a, the meshing surfaces 51a and 48a that are difficult to disengage can be easily formed.

Furthermore, since the inclination angles of the meshing 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 meshing is easy to mesh and difficult to come off. The surfaces 51a and 48a can be set.
In addition, the end surface of the boss sleeve 40 in which the concave portion 48 is formed is formed with a relief portion 52 in which the inner surface opposite to the meshing surface 48a with the convex portion 51 is shallower than the meshing surface 48a. The convex portion 51 easily enters the concave portion 48, and the meshing is smoothly performed.

In the invention relating to the shape of the convex portion and the concave portion, the number of the concave and convex portions is not limited to the above form, and three or more may be provided, and not the reverse taper in which both side surfaces are inclined but only the meshing side surface. It may be inclined.
Moreover, in the said form, although the meshing surface of an uneven | corrugated | grooved part is made into an inclined plane, one meshing surface of an uneven | corrugated | grooved part is made into the convex curved surface which swells in circular arc shape, and the other meshing surface is made into the concave curved surface which the said bulging part fits. You can also.
Furthermore, it is not necessary to make the entire meshing surface an inclined flat surface or a curved surface, for example, the convex side has the same width on the base side, the tip side is reverse tapered, the corresponding concave portion is made reverse taper on the bottom side, It is also possible to make the open side the same width. In other words, a mating 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 a convex portion whose root half is tapered or curved and the tip half is tapered and a concave portion fitted to the convex portion, 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 embodiment, the hammer mode can be selected by sliding the third gear. However, the third gear does not slide, and two modes, a drill mode and a hammer drill mode, are moved by the back and forth movement of the tool holder and the clutch. Even with other hammering tools such as a hammer drill that can select only the operation mode, the present invention relating to the shape of the convex portion and the concave portion can be employed.

  1 .... hammer drill, 2 .... main body housing, 3 .... brushless motor, 4 .... rotary shaft, 5 .... front housing, 6 .... output part, 7 .... handle, 11 .... first gear, ... Inner housing, 17 ... Tool holder, 18. Intermediate shaft, 23 ... Locking plate, 24 ... Receiving plate, 25 ... Coil spring, 27 ... Restriction plate, 30 ... Fourth gear, 31 ... Piston Cylinder, 33 ... striker, 35 ... bit, 39 ... second gear, 40 ... boss sleeve, 41 ... clutch, 48 ... recess, 48a, 51a ... meshing surface, 49 ... spline part, 51 ..Protrusions, 52 ..Relief parts, 53 ..Small diameter parts, 54 .. Third gear, 55 ..Gear part, 58 ..Slide plate, 59. ..Contact piece, 66 Material, 67 ... Support pin, 73 ... Mode switching lever, 75 ... Rotating part, 76 ... Knob, 77 ... First eccentric pin, 78 ... Second eccentric pin, P1 ... Root side contact point , P2... Tip side contact point, P3... Bottom side contact point, P4.

Claims (8)

A housing for housing the motor;
A tool holder that can hold a tip tool, can be moved back and forth in the housing, and is urged and projected forward;
A striking member provided to be movable back and forth into the tool holder;
An intermediate shaft provided in parallel with the tool holder in the housing and to which rotation of the motor is transmitted;
A gear that is provided on the intermediate shaft and transmits the rotation of the intermediate shaft to the tool holder;
A hammer drill provided on the intermediate shaft and converting the rotation of the intermediate shaft into a reciprocating motion of the striking member,
The gear is switchably provided between a first state in which the rotation of the intermediate shaft is transmitted and a second state in which the rotation of the intermediate shaft is not transmitted, and the state of the gear is changed from the outside of the housing. A mode switching member capable of switching operation is provided,
A hammer drill mode in which the gear is rotated integrally with the intermediate shaft by the mode switching member to cause the tool holder to rotate and reciprocate the striking member, and the gear is the intermediate shaft. A hammer drill characterized in that at least two operation modes can be selected: a hammer mode that is separated from the rotation of the hammer member and causes only the reciprocation of the striking member.   The gear slides between an engagement position that engages with the intermediate shaft and rotates integrally with the intermediate shaft and a non-engagement position at which the engagement with the intermediate shaft is released. 2. The hammer drill according to claim 1, wherein the hammer can be switched to a second state, and the mode switching member switches a sliding position of the gear from the outside of the housing. A clutch that is integrally rotatable with the intermediate shaft and is slidable in the axial direction;
The mode switching member can switch a sliding position of the clutch between a meshing position that meshes with the conversion member and rotates integrally, and a non-meshing position where the meshing with the conversion member is released. The drill mode in which the gear rotates together with the intermediate shaft and causes only rotation of the tool holder by switching between the engagement position and the non-engagement position of the clutch is further selectable. The hammer drill according to 2.   The hammer drill according to claim 2 or 3, wherein a rotation restricting means for restricting the rotation of the gear at the disengaged position of the gear is provided.   A guide shaft supported in parallel with the intermediate shaft in the housing, a slide member that is locked to the gear and can be moved back and forth along the guide shaft, and the slide member at the engagement position of the gear And an urging means for urging the gear to the disengaged position by moving the slide member in a counter-biasing direction of the urging means in accordance with the switching operation of the mode switching member. The hammer drill according to any one of claims 2 to 4, wherein the hammer drill slides.   The mode switching member includes two eccentric pins and is rotated, and one of the eccentric pins moves the slide member in the counter-biasing direction in accordance with the rotation operation. The hammer drill according to 5.   A small-diameter portion having a smaller diameter than the installation side of the conversion member is formed at the end of the intermediate shaft, and the gear is externally mounted on the small-diameter portion and provided at the root of the small-diameter portion at the engagement position. The hammer drill according to any one of claims 2 to 6, wherein the hammer drill engages with the engaging portion and rotates integrally with the intermediate shaft.   The motor is disposed below the intermediate shaft in the housing in a direction in which an axis of a rotating shaft intersects the intermediate shaft, and a handle is provided behind the tool holder. Item 8. The hammer drill according to any one of Items 1 to 7.

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