JP2016060034A - Hammer drill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress inclination of a mode switch member while suppressing an increase in a clearance between the mode switch member and a housing, and suitably prevent grease leakage and malfunction of mode switching.SOLUTION: A hammer drill 1 has a striking mechanism for striking a bit and a rotation mechanism for rotating the bit in a gear housing 2. A first clutch 16 engaging with and disengaging from a boss sleeve 12 and a second clutch 17 engaging with and disengaging from a second gear 15 are provided between the boss sleeve 12 of the striking mechanism and the second gear 15 of the rotation mechanism. A mode switch lever 31 having a pin 32, which is decentered from a rotation center O, is provided in the gear housing 2 rotatably. A rubber pin 45 for pressing a lever body 34 having the pin 32 to the gear housing 2 side is provided between the lever body 34 forming the mode switch lever 31 and a lever cap 36.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hammer drill capable of selecting a plurality of operation modes by rotating a mode switching member.

  The hammer drill is provided with a rotation mechanism for rotating a bit mounted at the tip and a striking mechanism for striking the bit in the housing, and the rotation of the motor can be transmitted to the bit via the rotation mechanism. It can be transmitted to the bit after being converted into a striking operation via a striking mechanism. Between the input members provided in the rotating mechanism and the striking mechanism, there is provided a clutch that engages one or both of the input members depending on the slide position and transmits the rotation of the motor. Is changed by a mode switching member provided on the outer surface of the housing, so that a plurality of operation modes (for example, drill mode, hammer drill mode, hammer mode) can be selected. As this mode switching member, for example, as disclosed in Patent Document 1, a member that is rotatably assembled to a housing and engages an eccentric pin provided on an end surface on the clutch side is well known. By rotating the mode switching member, the eccentric pin is moved to slide the clutch to the engagement position with the input member.

JP-A-9-272005

  Thus, since the mode switching member is rotatably assembled to the housing, a slight clearance is set between the mode switching member and the housing. Therefore, if the mode switching member or the housing is deformed due to heat generated by using the hammer drill, the clearance may be increased and the mode switching member may be tilted with respect to the rotation center before use. For this reason, the grease filled in the housing may leak, or the clutch may not move sufficiently due to the inclination of the eccentric pin, and the operation mode may not be switched smoothly.

  Accordingly, an object of the present invention is to provide a hammer drill that can suppress an increase in the clearance between the mode switching member and the housing, suppress the inclination of the mode switching member, and suitably prevent grease leakage and mode switching defects. It is a thing.

In order to achieve the above object, an invention according to claim 1 is provided with an impact mechanism for striking a bit and a rotation mechanism for rotating the bit in a housing, and input members respectively provided for the striking mechanism and the rotation mechanism. A clutch that engages and disengages with one or both of the input members in accordance with the movement between the input members is provided between the two, and a mode switching member having a pin that is eccentric from the center of rotation is rotatably provided on the housing. A hammer drill that enables selection of an operation mode in which the striking mechanism and / or the rotation mechanism is operated by sliding the clutch in conjunction with the movement of the pin accompanying the rotation operation of the mode switching member. An urging means for pressing the housing is provided.
In addition, the number of “clutch” is not limited to one, but includes one for each input member. In addition, the clutch linkage with respect to the movement of the pin includes not only the case where the pin is directly engaged with the clutch, but also the case where the pin indirectly links the clutch via another member such as an intermediate member.
According to a second aspect of the present invention, in the configuration of the first aspect, the mode switching member includes a contact portion that contacts the outer surface of the housing, is fitted into a mounting hole provided in the housing, and is provided with a pin. The split member and a second split member that is fitted to the first split member from the outside of the first split member and assembled to the housing are formed, and the urging means includes the first split member and the first split member. It is provided between the two divided members and presses the first divided member toward the housing.
According to a third aspect of the present invention, in the configuration of the first or second aspect, an intermediate member that engages with the clutch is provided in the housing so as to be urged toward the pin in the crossing direction with the pin and brought into contact with the pin. As the pin moves, the urging means moves the clutch through the intermediate member at the rotational position of the mode switching member where the pin is at the rearmost side in the urging direction of the intermediate member. It arrange | positions in the area | region ahead of the urging | biasing direction of an intermediate member rather than the rotation center, It is characterized by the above-mentioned.
According to a fourth aspect of the present invention, in any one of the first to third aspects, the urging means is a rubber pin.

According to the first aspect of the present invention, by adopting the biasing means, the increase in the clearance between the mode switching member and the housing is suppressed, the inclination of the mode switching member is suppressed, and grease leakage and mode switching problems are prevented. It can prevent suitably.
According to the second aspect of the invention, in addition to the effect of the first aspect, the biasing means can be accommodated between the first divided member and the second divided member without being exposed.
According to the third aspect of the invention, in addition to the effect of the first or second aspect, the urging means can be effectively disposed at a position where the inclination of the mode switching member due to the urging to the pin is suppressed. .
According to the fourth aspect of the present invention, in addition to the effect of any one of the first to third aspects, the biasing means can be easily configured by the rubber pin.

It is a partial longitudinal cross-sectional view of a hammer drill. It is a disassembled perspective view of a mode switching lever.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a partial longitudinal sectional view showing an example of a hammer drill. In this hammer drill 1, a motor housing 3 housing a motor 4 forwardly is assembled to the rear of a gear housing 2 as a housing of the present invention (the left side in FIG. 1 is the front), and an output shaft 5 of the motor 4 is assembled. The inner housing 6 mounted on the rear part in the gear housing 2 is pivotally supported so as to protrude into the gear housing 2. An intermediate shaft 7 is disposed in the front-rear direction between the gear housing 2 and the inner housing 6 below the output shaft 5 and is rotatably supported by front and rear ball bearings 8 and 9. A first gear 10 fixed to the rear end is meshed with a pinion 11 provided at the front end of the output shaft 5.

In the intermediate shaft 7, a boss sleeve 12 having a swash bearing 13 having an inclined axis line is rotatably provided in front of the first gear 10, and a spline portion 14 is formed in front of the boss sleeve 12.
A second gear 15 is rotatably provided in front of the spline portion 14 in the intermediate shaft 7.
In the spline portion 14 between the boss sleeve 12 and the second gear 15, two first and second clutches 16 and 17 can move back and forth along the spline portion 14 and are integrated with the intermediate shaft 7. It is coupled so that it can rotate. The first and second clutches 16 and 17 have the same sleeve shape arranged symmetrically in the front-rear direction. The rear end of the first clutch 16 is the front end of the boss sleeve 12, and the front end of the second clutch 17 is the second gear 15. Each can be engaged with the rear end. In addition, concave grooves 18 are formed in the peripheral surfaces of the first and second clutches 16 and 17, respectively.

  On the other hand, a tool holder 19 parallel to the intermediate shaft 7 is rotatably supported via a ball bearing 20 and a bearing 21 above the intermediate shaft 7 in the gear housing 2. A piston cylinder 22 is accommodated in a rear portion of the tool holder 19 so as to be movable back and forth, and a rear end thereof is connected to an arm 23 provided on the swash bearing 13. A striking element 25 is accommodated in the piston cylinder 22 via an air chamber 24 so as to be movable back and forth, and an intermediate element 26 is accommodated in the tool holder 19 in front of the striking element 25 so as to be movable back and forth. .

  Therefore, here, a striking mechanism is formed by components from the boss sleeve 12 to the swash bearing 13, the arm 23, the piston cylinder 22, the striking element 25, and the intermediate element 26, and the boss sleeve 12 serves as an input member of the striking mechanism. A bit (not shown) is inserted into the tool holder 19 in front of the intermediate element 26, and an operation sleeve 27 is provided at the front end of the tool holder 19 to prevent and release the inserted bit. The tool holder 19 is provided with a gear 28 that meshes with the second gear 15. Therefore, here, a rotation mechanism is formed by the components from the second gear 15 to the gear 28 and the tool holder 19, and the second gear 15 becomes an input member of the rotation mechanism.

Below the first and second clutches 16 and 17, first and second change plates 29 and 30 as intermediate members are slidable back and forth, and an engagement piece (not shown) of the first change plate 29 is provided. Engaging pieces (not shown) of the second change plate 30 are engaged with the concave grooves 18 of the second clutch 17 in the concave grooves 18 of the first clutch 16, respectively. Both the change plates 29 and 30 are urged in the direction away from each other by a coil spring (not shown) provided between them.
A mode switching lever 31 as a mode switching member is rotatably mounted on the lower surface of the gear housing 2. A pin 32 is provided upward at an eccentric position at the upper end of the mode switching lever 31, and the pin 32 passes through the first change plate 29 and the second change plate 30 at the same time. And the forward slide of the second change plate 30 are regulated.

As shown in FIG. 2, the mode switching lever 31 is rotatably inserted into a mounting hole 33 provided on the lower surface of the gear housing 2, and a pin 32 protrudes upward at an eccentric position, and a cam portion is provided at the base thereof. 35 is a resin-made disc-shaped first disc-shaped divided member, and is fitted to the lever main body 34 from below with a larger diameter than the lever main body 34, and can be rotated in the switching range of each operation mode. The lever cap 36 is a resin-made disc-shaped second divided member.
First, the lever main body 34 has a disk portion 37 as a contact portion that contacts the lower surface of the gear housing 2 in a state of being inserted into the mounting hole 33, and the lower surface of the disk portion 37 rotates the lever main body 34. A fitting projection 38 projects downward along the diameter direction connecting the center and the center of the pin 32, and a triangular convex portion 39 projects on the lower surface of the end portion of the fitting projection 38 on the pin 32 side. Has been. On the upper side of the disc portion 37, the lever main body 34 is externally provided with an O-ring 40 that seals between the mounting hole 33.

Next, the lever cap 36 includes a circular bottom portion 41 into which the disc portion 37 of the lever main body 34 can be fitted, and a flange portion 42 extending on the outer periphery of the circular bottom portion 41. A deep-bottomed operation portion 43 into which the fitting protrusion 38 of the lever main body 34 can be fitted is formed in the diameter direction. Due to the fitting of the fitting protrusion 38 and the operation portion 43, the lever main body 34 and the lever cap 36 are integrated in the rotation direction. Further, the operation portion 43 is formed with a triangular window 44 into which the convex portion 39 is fitted when the fitting protrusion 38 is fitted.
A rubber pin 45 as an urging means is provided between the lever main body 34 and the lever cap 36. The rubber pin 45 is held vertically between the receiving portion 46 provided on the fitting projection 38 of the lever main body 34 and the circular bottom 41 of the lever cap 36, and this holding position is the rotation of the lever main body 34. A point-symmetrical position with respect to the pin 32 is set with respect to the center O. Therefore, at the rotational position of the mode switching lever 31 in which the pin 32 is at the foremost position as shown in FIG. 1, the rubber pin 45 is positioned in a region on the rear side from the rotational center O.

  The mode switching lever 31 is attached by a lever cover 47 assembled to the lower surface of the gear housing 2. In other words, the lever main body 34 is inserted into the mounting hole 33, and the flange portion 42 of the lever cap 36 is fitted into the concave portion 48 provided in the lower surface of the gear housing 2, and the through hole is fitted into the circular bottom portion 41. When the lever cover 47 having the above is assembled to the lower surface of the gear housing 2, the flange portion 42 is pressed from below by the lever cover 47, and the mode switching lever 31 is rotatably mounted in a state of being prevented from coming down. In this mounted state, the rubber pin 45 is compressed in the axial direction between the lever main body 34 and the lever cap 36, and presses the lever main body 34 toward the gear housing 2 and the lever cap 36 toward the lever cover 47. Therefore, the disc portion 37 of the lever main body 34 is pressed against the lower surface of the gear housing 2 by the urging of the rubber pin 45, and the flange portion 42 of the lever cap 36 is pressed against the upper surface of the lever cover 47.

  On the other hand, a lock plate 49 that engages with the second gear 15 in the retracted position is provided below the first change plate 29 so as to be slidable in the front-rear direction, and is provided between the coil spring and the inner surface of the gear housing 2. The rear end of the lock plate 49 is in contact with the cam portion 35 of the mode switching lever 31 so that the lock plate 49 can slide back and forth according to the position of the cam portion 35. It has become.

  In the hammer drill 1 configured as described above, the first and second clutches 16 and 17 are slid through the first and second change plates 29 and 30 by the rotation operation of the mode switching lever 31, thereby operating modes. Is selectable.

First, when the mode switching lever 31 is set to the rotational position in which the operation portion 43 is directed in the front-rear direction so that the convex portion 39 appearing on the lever cap 36 is at the front end, the pin 32 advances the first change plate 29 and the coil spring is moved forward. Then, the second change plate 30 is also advanced. Therefore, the second clutch 17 is engaged with the second gear 15, and the first clutch 16 moves forward and enters a drill mode in which it is separated from the boss sleeve 12.
Therefore, when the motor 4 rotates, the rotation of the intermediate shaft 7 is transmitted to the second gear 15 via the second clutch 17 and rotates the tool holder 19 via the gear 28, so that only the rotation is applied to the bit. At this time, the lock plate 49 is moved forward by the cam portion 35 located on the front side and separated from the second gear 15. On the lower surface of the gear housing 2, a leaf spring 51 having a locking portion at the center in the left-right direction is held in front of the mode switching lever 31, and the outer periphery of the flange portion 42 of the lever cap 36 is Notches 52, 52,... In which the locking portions are elastically locked at the rotational positions of the respective modes are formed so as to be positioned at the respective rotational positions.

Next, from the drill mode, when the mode switching lever 31 is rotated to the right by a predetermined angle when viewed from below, the pin 32 moves rearward and the first change plate 29 is moved to the coil spring while the second change plate 30 remains unchanged. Retreat by energizing. Therefore, the second clutch 17 is in the hammer drill mode in which the first clutch 16 moves backward and engages with the boss sleeve 12 while being engaged with the second gear 15.
Accordingly, when the motor 4 rotates, the rotation of the intermediate shaft 7 is transmitted to the boss sleeve 12 via the first clutch 16, and the arm 23 swings back and forth by the action of the swash bearing 13 to reciprocate the piston cylinder 22. The striker 25 reciprocates due to the action of the air spring in the air chamber 24 and strikes the bit via the intermediate element 26. At the same time, the rotation of the intermediate shaft 7 is transmitted to the second gear 15 via the second clutch 17, and the tool holder 19 is rotated via the gear 28. Therefore, the bit is rotated in addition to the impact. At this time, the lock plate 49 remains in the forward position.

Next, when the mode switching lever 31 is further rotated to the right by a predetermined angle from the hammer drill mode, the pin 32 moves rearward and the second change plate 30 is biased by the coil spring while the first change plate 29 remains unchanged. Retreat against. Therefore, the first clutch 16 is in the hammer mode in which the second clutch 17 moves backward and separates from the second gear 15 while being engaged with the boss sleeve 12.
Accordingly, when the motor 4 rotates, the rotation of the intermediate shaft 7 is transmitted to the boss sleeve 12 via the first clutch 16, and the arm 23 swings back and forth to reciprocate the piston cylinder 22, so that the striker 25 reciprocates. Then hit a bit. At this time, the cam portion 35 is also moved rearward to slide the lock plate 49 to the retracted position where the lock plate 49 is engaged with the second gear 15, so that the rotation of the tool holder 19 is locked.

  Note that, at the intermediate rotational position between the hammer drill mode and the hammer mode, the retracted position of the second change plate 30 does not change, and the first change plate 29 is also urged to the retracted position via the coil spring. Therefore, the second clutch 17 is in a retracted position away from the second gear 15, and the first clutch 16 is engaged with the boss sleeve 12, so that only the striking operation is transmitted to the bit as in the hammer mode. However, here, since the cam portion 35 slides the lock plate 49 to the forward movement position, the lock plate 49 is separated from the second gear 15 and the rotation lock of the tool holder 19 is released. Therefore, the bit can be rotated to an arbitrary angle around the axis (neutral mode).

  During the operation of the hammer drill 1, each component of the mode switching lever 31 and the gear housing 2 are deformed due to heat generation, moisture adhesion, and the like, and between the lever main body 34 of the mode switching lever 31 and the mounting hole 33 of the gear housing 2. May increase the clearance. However, since the lever main body 34 is always pressed against the lower surface of the gear housing 2 by the rubber pin 45, the lever main body 34 does not tilt with respect to the rotation center O before use. As a result, the sealing performance of the O-ring 40 is lowered and the grease filled in the gear housing 2 leaks, or the movement of the first and second clutches 16 and 17 is insufficient, so that the operation mode can be switched smoothly. There is no risk of losing.

  Thus, according to the hammer drill 1 of the said form, by providing the urging means (rubber pin 45) which presses the mode switching lever 31 to the gear housing 2 side, between the mode switching lever 31 and the gear housing 2 is provided. It is possible to suppress the increase of the clearance and suppress the inclination of the mode switching lever 31 and to appropriately prevent the grease leakage and the mode switching failure.

  In particular, here, the mode switching lever 31 is fitted into a mounting hole 33 provided in the gear housing 2 with a disk portion 37 that contacts the outer surface of the gear housing 2, and the pin 32 is protruded into the gear housing 2. A rubber pin 45 is provided between the lever main body 34 and the lever cap 36 and is formed from a lever main body 34 and a lever cap 36 that is fitted to the lever main body 34 from the outside of the lever main body 34 and assembled to the gear housing 2. By pressing the lever body 34 toward the gear housing 2, the rubber pin 45 can be accommodated between the lever body 34 and the lever cap 36 without being exposed.

Further, the rubber pin 45 is located at the rotational position of the mode switching lever 31 in which the pin 32 is located at the rearmost side in the urging direction of the first change plate 29, and the first change plate 29 Since the rubber pin 45 is disposed in the region on the front side in the urging direction, the rubber pin 45 can be effectively disposed at a position where the inclination of the lever main body 34 due to the urging to the pin 32 is suppressed.
Furthermore, since the urging means is the rubber pin 45, the urging means can be configured easily.

The biasing means is not limited to the rubber pin, and other means such as a coil spring, a leaf spring, and a disc spring can be employed. The housing position of the urging means is not limited to the position between the fitting projection 38 and the operation portion 43, for example, between the disc portion 37 of the lever main body 34 and the circular bottom portion 41 of the lever cap 36. There is no problem.
Further, the urging means is not limited to the structure housed in the mode switching lever 31, and for example, the urging means such as a leaf spring is provided between the flange portion 42 of the lever cap 36 and the lever cover 47, so that the mode switching lever 31 as a whole. Can also be pressed against the lower surface of the gear housing 2. It is also conceivable that an urging means such as a coil spring is provided between the flange portion provided on the mode switching member in the housing and the inner surface of the housing to press the mode switching member to the housing side. Therefore, the mode switching member does not have to be a two-part structure as in the above embodiment, and an integral type member can be adopted. Further, in the case of an integrated mode switching member, a structure that is mounted on the housing without a lever cover may be employed.

On the other hand, the shape of the mode switching member is not limited to a disk shape but can be changed as appropriate as long as it can be rotated. Further, the mode switching member can be provided not only on the lower surface of the housing but also on the side surface and the upper surface.
And not only the case where the mode switching member is pressed and biased toward the housing side, it is also conceivable that the mode switching member is tensioned with a spring or the like stretched between the mode switching member and the housing inner side.

In addition, the structure of the hammer drill is not limited to the structure in which the two clutches are slid with the pins through the two change plates as in the above embodiment, and the operation mode is changed by directly engaging the pin of the mode switching member with one clutch. You may choose.
In the above embodiment, the lock plate is provided and the neutral mode can be selected, but the lock plate is omitted and only the three operation modes of the hammer mode, the hammer drill mode, and the drill mode can be selected, The number of operation modes and the mode content are not limited to the above-described forms, such as one in which two operation modes of a hammer mode and a hammer drill mode, or a drill mode and a hammer drill mode can be selected.

  1 .... hammer drill, 2 .... gear housing, 3 .... motor housing, 4 .... motor, 5 .... output shaft, 6 .... inner housing, 7 .... intermediate shaft, 10 .... first gear, ... Boss sleeve, 13 ... Swash bearing, 14 ... Spline part, 15 ... Second gear, 16 ... First clutch, 17 ... Second clutch, 19 ... Tool holder, 22 ... Piston cylinder, 23 ... · Arm, 24 · · Air chamber, 25 · · Strike, 26 · · Meson, 28 · · Gear, 29 · · 1st change plate, 30 · · 2nd change plate, 31 · · Mode switching lever, 32 · · · Pins 33 · · Mounting holes 34 · · Lever body 36 · · Lever caps 38 · · Fitting projections 40 · · O-rings 43 · · Operation parts 45 · · Rubber pins 46 · · Receiving parts 47 Lever cover.

Claims (4)

In the housing, a striking mechanism for striking the bit and a rotating mechanism for rotating the bit are provided, and between the input members provided in the striking mechanism and the rotating mechanism, according to the movement between the two input members. While providing a clutch for engaging and disengaging one or both of the input members.
The mode switching member having a pin eccentric from the rotation center is rotatably provided in the housing, and the clutch is moved in conjunction with the movement of the pin in accordance with the rotation operation of the mode switching member. A hammer drill capable of selecting a mechanism and / or an operation mode in which the rotating mechanism operates,
A hammer drill comprising a biasing means for pressing the mode switching member toward the housing.   The mode switching member is fitted to a mounting hole provided in the housing with an abutting portion that abuts on the outer surface of the housing, and the first divided member having the pin, and the first divided member The urging means includes a first divided member and a second divided member. The second divided member is fitted to the first divided member from the outside and assembled to the housing. The hammer drill according to claim 1, wherein the hammer drill is provided in between to press the first divided member toward the housing.   An intermediate member that engages with the clutch is provided in the housing so as to be urged toward the pin in the crossing direction with the pin, and is brought into contact with the pin. As the means for moving the clutch, the urging means is configured such that the pin is at the rotational position of the mode switching member at the rearmost side in the urging direction of the intermediate member, and is more than the rotational center of the mode switching member. The hammer drill according to claim 1, wherein the hammer drill is disposed in a region on the front side in the biasing direction of the intermediate member.   The hammer drill according to any one of claims 1 to 3, wherein the biasing means is a rubber pin.

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