JP2010012556A - Hammer drill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent comfortable feeling of use from being lost due to heat generated inside. <P>SOLUTION: In a hammer drill 1 having a mode switching knob 48 for switching an operation mode by operation from the outside which is mounted at a gear housing 2, a cover 62 covering the mode switching knob 48 except a knob part 49, supporting it in a thrust direction so as not to be loosed, and forming an air layer between itself and the gear housing 2 is mounted at the outer surface of the mounting part of the mode switching knob 48 in the gear housing 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hammer drill capable of imparting rotation and / or hitting to a bit at a tip.

  For example, as shown in Patent Literatures 1 and 2, a hammer drill supports a tool holder that holds a bit at the front end in the front of the housing, and inverts the bit through an intermediate member by a reciprocating hammer. A striking mechanism that strikes automatically is provided, and an intermediate shaft to which rotation of the motor output shaft is transmitted is supported in parallel with the tool holder, and the intermediate shaft is integrally rotated with the intermediate shaft and slid in the axial direction. A possible clutch member, a second gear that is loosely fitted on the intermediate shaft in front of the clutch member and meshed with a gear on the tool holder side, and is loosely fitted on the intermediate shaft behind the clutch member, and the intermediate shaft is rotated forward and backward. 2. Description of the Related Art A boss sleeve that is converted into motion and transmitted to a striking mechanism and a switching lever (mode switching member) that is provided with a pin that engages with a groove provided around a clutch member at an eccentric position are known.

  That is, the clutch member is slid from the outside of the housing by the eccentric movement of the pusher by the rotation operation of the switching lever, and the clutch member is engaged with and disengaged from the second gear and / or the boss sleeve, so that the clutch member is only the second gear. A drill mode in which only the rotation is applied to the bit, a hammer drill mode in which both the second gear and the boss sleeve are engaged and rotation + striking is applied to the bit, and a bit in which only the boss sleeve is engaged It is possible to select a hammer mode in which only hitting is applied.

JP-A-6-210507 No. 6-50089

  In such a hammer drill, the housing is likely to become hot due to heat generated inside during use, and when the operator rotates the mode switching member, there is a risk that the housing may be touched to cause discomfort.

  Accordingly, an object of the present invention is to provide a hammer drill that does not impair the feeling of use due to heat generated inside.

In order to achieve the above object, according to the first aspect of the present invention, the mode switching member is covered on the outer surface of the mounting portion of the housing except for the operation portion, and is supported to prevent the mode switching member from being detached. A cover for forming an air layer is attached.
According to a second aspect of the present invention, in the configuration of the first aspect, the mode switching member and the cover are provided on the lower surface of the housing in order to more reliably maintain the feeling of use.
According to a third aspect of the present invention, in the configuration of the first or second aspect, in order to facilitate the mounting of the cover on the housing, the cover is mounted on the convex portion provided on one of the housing and the cover. It is characterized in that it is carried out by fitting with a recess or hole provided on the other side.

According to the first aspect of the present invention, since the cover does not touch the housing whose temperature has been increased, the feeling of use is not impaired by the heat generated inside. Moreover, it also becomes a rational structure by which the mode switching member is supported to prevent the cover from being removed.
According to the second aspect of the present invention, in addition to the effect of the first aspect, in the case where the hand is attached to the lower surface of the housing for supporting the hammer drill in addition to the operation of the mode switching member. Similarly, it is possible to prevent the occurrence of discomfort due to heat, and to maintain a more reliable feeling of use.
According to the third aspect of the invention, in addition to the effect of the first or second aspect, the cover can be easily attached to the housing.

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, FIG. 2 is a transverse sectional view of a clutch portion, and a hammer drill 1 includes a gear housing 2 in which a rotation / blow mechanism is provided, and its rear (see FIG. 1) and a motor housing 3 for housing the motor 4, and a tool holder 6 on which a bit can be mounted at the front end is rotatably supported in front of the gear housing 2.
The tool holder 6 has a cylindrical shape in which an intermediate portion 7 is rotatably supported by a ball bearing 8 at the front end of the gear housing 2 and a rear large-diameter portion 9 is rotatably supported by an inner housing 10 assembled at the rear in the gear housing 2. At the front end of the body that protrudes from the gear housing 2, an operation sleeve 11 is provided for operating the inserted bit.

  A gear 12 is externally provided on the outer periphery of the large diameter portion 9. The gear 12 is positioned in contact with a stopper ring 13 which is fixedly attached to the large-diameter portion 9 on the front side, and balls 14 held at predetermined intervals in the circumferential direction are externally mounted on the large-diameter portion 9. The rotation is regulated by being pressed against the concave portion of the stopper ring 13 by the coil spring 15 via the washer 16. That is, when a load exceeding the urging force of the coil spring 15 is applied to the gear 12, the ball 14 rides over the concave portion of the stopper ring 13 and idles the gear 12, thereby blocking the rotation transmission to the tool holder 6. Is formed.

Further, an impact bolt 17 located behind the bit is accommodated in the intermediate portion 7 of the tool holder 6 so as to be movable back and forth, and behind the impact bolt 17 is a sheath that is externally mounted on the impact bolt 17 and restricts its retreat position. A ring 18 is provided. The receiving ring 18 is pressed and fixed to a step portion 21 provided in the intermediate portion 7 by a coil spring 20 interposed between the receiving ring 18 and a cylindrical cap 19 assembled in the large-diameter portion 9 at the rear. The rear end of the impact bolt 17 is fitted to the rear end of 19 and the front end of a striker 25 (to be described later) is gripped in the case of idle driving such as when the tool holder 6 does not have a bit. An O-ring 22 that restricts reciprocation is accommodated.
A cylindrical piston cylinder 23 having an opening at the front is loosely inserted in the large-diameter portion 9, and a striker 25 is accommodated in the piston cylinder 23 via an air chamber 24 so as to be movable back and forth. .

  On the other hand, below the output shaft 5 of the motor 4 in the gear housing 2, an intermediate shaft 26 is supported in parallel with the tool holder 6 and the output shaft 5 by front and rear ball bearings 27 and 28, and is provided at the rear end. The first gear 29 is engaged with the output shaft 5. Spline teeth 30 are formed at an intermediate portion of the intermediate shaft 26, and a second gear 31 is externally mounted so as to be rotatable separately from the intermediate shaft 26 between the ball bearing 27 and the tool holder 6. Is engaged with the gear 12. Further, a boss sleeve 32 is externally mounted on the rear side of the spline teeth 30 so as to be rotatable separately from the intermediate shaft 26, and a swash bearing 33 having an inclined axis is provided on the outer periphery of the boss sleeve 32. An upper end of a connecting arm 34 that is rotatably fitted and protrudes from the upper portion of the swash bearing 33 is rotatably connected to the rear end of the piston cylinder 23.

  The coupling arm 34 and the piston cylinder 23 are coupled by inserting a receiving plate 36 between a pair of coupling pieces 35, 35 projecting at a predetermined interval in the left-right direction at the rear end of the piston cylinder 23. The upper end of the connecting arm 34 is penetrated orthogonally to a joint pin 37 that penetrates the connecting pieces 35, 35 and the receiving plate 36 in the left-right direction and integrates both. As shown in FIG. 3, the receiving plate 36 is a band-shaped metal plate that is bent to have a U-shape in a plan view with a width that matches the interval between the connecting pieces 35, 35. In the center, a notch 38 is formed that leaves a pair of contact portions 39, 39 at the upper and lower ends, and through holes 41 through which the joint pins 37 pass are formed in the left and right side plates 40, 40, respectively. At the center of the edge, a quadrangular protrusion 42 having a vertical width smaller than that of the side plate 40 is provided. Further, the vertical length of the base end of the receiving plate 36 is formed larger than the vertical length of the side plate 40.

Therefore, when the receiving plate 36 is inserted between the connecting pieces 35 and 35 with the base end in front, the abutting portions 39 and 39 abut near the upper and lower ends of the rear surface of the piston cylinder 23 as shown in FIG. The front end of 40 is positioned at a position protruding rearward from the connecting piece 35. At this time, since the side plates 40 and 40 are elastically pressed into the connecting pieces 35 and 35, the receiving plate 36 is not dropped from the connecting pieces 35 and 35 during the assembly. Can be done easily. When the joint pin 37 is passed through the connecting piece 35 and the receiving plate 36 and the upper end of the connecting arm 34 is passed through the joint pin 37, the connection between the connecting arm 34 and the piston cylinder 23 is completed.
43 is a coil spring provided at the rear of the piston cylinder 23, and the front end abuts the end edges of the both side plates 40 of the receiving plate 36 with the projections 42 inside, while the rear end is the inner surface of the inner housing 10. The piston cylinder 23 is urged forward through the receiving plate 36 by being respectively positioned by being fitted to the bosses 44 projecting from the boss 44.

  A sleeve-like clutch 45 is spline-coupled to the spline teeth 30 of the intermediate shaft 26 so as to be rotatable integrally with the intermediate shaft 26 and slidable in the front-rear direction. 31 and / or the boss sleeve 32 can be engaged / disengaged. That is, in the forward position, only the second gear 31 is engaged and integrated with the intermediate shaft 26 in the rotational direction, and in the backward position, only the boss sleeve 32 is engaged and integrated with the intermediate shaft 26 in the rotational direction. In the position, it is engaged with both the second gear 31 and the boss sleeve 32 to be integrated with the intermediate shaft 26 in the rotational direction. Further, a V-shaped fitting groove 46 is provided around the outer periphery of the clutch 45.

  A cylindrical mounting portion 47 is formed below the clutch 45 on the lower surface of the gear housing 2, and a mode switching knob 48 as a mode switching member is rotatably fitted to the mounting portion 47. The mode switching knob 48 has a disk shape in which a knob portion 49 serving as an operation portion is protruded on the lower surface, and a cylindrical holding tube 50 at an eccentric position from the rotation center on the upper surface on the inner side of the gear housing 2. And the engaging pin 51 is accommodated in the holding cylinder 50. The engagement pin 51 has a tapered shape whose upper end is fitted into the fitting groove 46 of the clutch 45, and is projected and biased upward by a coil spring 52 housed below, so that the tapered upper end is fitted into the fitting groove. 46 is fitted. Therefore, when the mode switching knob 48 is rotated, the engaging pin 51 moves eccentrically with the holding cylinder 50 fitted in the fitting groove 46, so that the clutch 45 also moves according to the amount of movement of the engaging pin 51 in the front-rear direction. It will move back and forth.

In addition, on the upper surface of the mode switching knob 48, a restriction cylinder 53 that is concentric with the center of rotation and partly the same height as the holding cylinder 50 is provided as a restriction cylinder 53. Thus, the phase of the restricting portion 54 can be changed. In front of the mode switching knob 48 in the gear housing 2, there is a U-shaped lower plate 56 in the front-rear direction, and a lock tooth 58 formed on the second gear 31 that is bent upward from the front end of the lower plate 56. A lock plate 55 having an L-shape in side view, which can be engaged with a U-shaped front plate 57, is slidable in the front-rear direction and is provided on the lower plate 56 by a coil spring 59 provided on the front inner surface of the gear housing 2. 50 or the rear position where the restricting portion 54 abuts.
A leaf spring 60 is held in the left-right direction in front of the mode switching knob 48 on the lower surface of the gear housing 2, while the upper peripheral edge of the mode switching knob 48 corresponds to the rotational position of each operation mode described later. The leaf springs 60 are formed with notches 61, 61,. Therefore, a click action is obtained when the mode switching knob 48 is rotated, and the rotation operation to each operation mode is facilitated.

  A cover 62 is provided on the lower surface of the gear housing 2. The cover 62 is a synthetic resin dish having an upper opening, and circular protrusions 64 are formed by projecting holes 63, 63 formed on the left and right side surfaces on the left and right side surfaces of the mounting portion 47 of the gear housing 2. 4 and 5, the peripheral edge of the opening abuts against the lower surface of the gear housing 2 and the bottom surface of the cover 62 and the lower surface of the gear housing 2 are not in contact with each other as shown in FIGS. Mounted on the housing 2. At the center of the bottom of the cover 62, a through-hole 65 is formed that fits to the periphery of the lower surface of the mode switching knob 48 in the mounted state and prevents the mode switching knob 48 from coming out from below in the thrust direction.

Therefore, the cover 62 covers the mode switching knob 48 except for the lower surface including the knob portion 49 in the mounted state on the gear housing 2, and forms an air layer between the cover 62 and the gear housing 2.
In addition, on both side surfaces of the gear housing 2, notches 66 are respectively provided at the upper end of the cover 62 above the circular convex portion 64, and by inserting the tip of the driver into the circular convex portion, the circular convex portion is provided. The cover 62 can be removed by detaching the hole 63 from the portion 64. Further, 67 shown in FIG. 2 is a handle formed downward at the rear of the motor housing 3, and 68 is a side handle attached to the front end of the gear housing 2 and protruding downward.

  In the hammer drill 1 configured as described above, as shown in FIG. 1, the holding cylinder 50 and the engaging pin 51 are located closest to the front at the rotational operation position of the mode switching knob 48 with the knob portion 49 facing forward. . Therefore, the clutch 45 that engages with the engagement pin 51 slides to the forward movement position, and the drill mode in which the clutch 45 is engaged with the second gear 31 is set. At this time, the lock plate 55 is moved to the forward movement position against the bias of the coil spring 59 by the holding cylinder 50, and the slide is restricted at a position where the front plate 57 does not engage with the lock teeth 58 of the second gear 31. ing.

When the bit is mounted on the tool holder 6 and the motor 4 is driven in this drill mode, the intermediate shaft 26 rotates, and the rotation is transmitted to the tool holder 6 via the clutch 45, the second gear 31, and the gear 12, and the bit is Rotate. On the other hand, since the rotation is not transmitted to the boss sleeve 32 from which the advanced clutch 45 is separated, the piston cylinder 23 does not reciprocate. Therefore, the bit is only rotated.
At this time, the boss sleeve 32 tries to rotate due to friction between the outer surface of the rotating intermediate shaft 26 and the inner surface of the boss sleeve 32. As described above, the piston cylinder 23 is urged to the forward position by the coil spring 43 and connected. Since the retreat of the arm 34 is restricted together with the arm 34, the piston cylinder 23 does not reciprocate, and an unnecessary hitting operation does not occur.

  Next, when the mode switching knob 48 is rotated to the right by about 90 ° so that the knob portion 49 is substantially horizontal, the holding cylinder 50 and the engaging pin 51 are also rotated to the right. Then, the clutch 45 is slid to the intermediate position. Therefore, the hammer drill mode is employed in which the rear surface of the clutch 45 is engaged with the boss sleeve 32 while maintaining the connection with the second gear 31. At this time, even if the holding cylinder 50 moves, the restricting portion 54 shifts the phase and directly contacts the lower plate 56 to restrict the slide of the lock plate 55, so that the disengagement position of the lock plate 55 does not change. . As shown in FIG. 5, marks 69, 69,... Representing the respective operation modes are attached to the lower surface of the cover 62 in correspondence with the rotational positions of the knob portions 49 of the respective operation modes. In the drill mode, a mark 69 is attached to the surface using the circular convex portion 64 in the direction in which the knob portion 49 faces.

  When the motor 4 is driven in this hammer drill mode, the rotation of the intermediate shaft 26 is transmitted to the tool holder 6 via the clutch 45, the second gear 31, and the gear 12 to rotate the bit, while the boss coupled to the clutch 45 It is also transmitted to the sleeve 32. Therefore, the swash bearing 33 swings and the connecting arm 34 reciprocates the piston cylinder 23 against the bias of the coil spring 43. By this operation, the striker 25 in the piston cylinder 23 reciprocally moves and strikes the impact bolt 17 with which the rear end of the bit abuts. Therefore, the bit is transmitted in addition to the rotation.

Next, when the mode switching knob 48 is further rotated clockwise by about 45 °, the holding cylinder 50 and the engagement pin 51 are also rotated rightward and moved rearward, so that the clutch 45 is moved to the reverse position via the engagement pin 51. A hammer mode (neutral mode) is established in which the slider slides away from the second gear 31 and engages only with the boss sleeve 32. Here, even if the holding cylinder 50 moves, the restricting portion 54 shifts the phase and directly contacts the lower plate 56 to restrict the slide of the lock plate 55, so that the disengagement position of the lock plate 55 does not change. .
When the motor 4 is driven in this state, the rotation of the intermediate shaft 26 is not transmitted to the second gear 31, and the tool holder 6 also does not rotate, but the boss sleeve 32 rotates and reciprocates the piston cylinder 23. Only the blow will be transmitted. However, since the rotation of the second gear 31 is not locked, the rotation of the tool holder 6 is free and the angle around the bit axis can be arbitrarily changed.

Next, when the mode switching knob 48 is further rotated to the right by about 90 °, the holding cylinder 50 and the engaging pin 51 are also rotated to the right, but the neutral mode is a straight line in the front-rear direction passing through the center of rotation of the mode switching knob 48. On the other hand, since the phase is axisymmetric and the position in the front-rear direction does not change, the clutch 45 continues to engage with the boss sleeve 32 in the retracted position and enters the hammer mode in which the clutch 45 is separated from the second gear 31. However, since the restricting portion 54 moves rearward from the holding cylinder 50 with a phase shift, the lock plate 55 moves backward until the lower plate 56 contacts the holding cylinder 50, and the front plate 57 is moved away from the second gear 31. The lock teeth 58 are engaged.
Therefore, when the motor 4 is driven in this state, the rotation of the intermediate shaft 26 is not transmitted to the second gear 31 and the tool holder 6 does not rotate, but the boss sleeve 32 rotates to reciprocate the piston cylinder 23. Only a blow is transmitted to the bit. Further, the rotation of the tool holder 6 is locked and the angle of the bit is fixed.

  Thus, when the hammer drill 1 is used in each operation mode, heat is generated at the intermediate shaft 26 portion where the friction with the parts is large, and this is also transmitted to the gear housing 2. However, since the cover 62 is attached to the lower part of the gear housing 2 through an air layer, the heat of the gear housing 2 is hardly transmitted to the cover 62, and the temperature rise of the cover 62 is suppressed. Therefore, even when the operator touches the cover 62 when rotating the mode switching knob 48 at the lower part of the gear housing 2, there is no discomfort due to heat.

  As described above, according to the hammer drill 1 of the above-described form, the mode switching knob 48 is covered on the outer surface of the gear housing 2 where the mode switching knob 48 is mounted except for the knob portion 49 and supported in the thrust direction. Since the cover 62 that forms an air layer between the gear housing 2 and the gear housing 2 is mounted, the gear housing 2 that has risen in temperature on the lower surface side of the hammer drill 1 is not touched. There is nothing. In addition, the mode switching knob 48 is supported in the thrust direction by using the cover 62.

In particular, here, since the mode switching knob 48 and the cover 62 are provided on the lower surface of the gear housing 2, a hand is placed on the lower surface of the gear housing 2 to support the hammer drill 1 in addition to when the mode switching knob 48 is rotated. Similarly, when working together, it is possible to prevent generation of discomfort due to heat.
Further, the cover 62 is attached by fitting the hole 63 provided in the cover 62 with the circular convex portion 64 provided in the gear housing 2, so that the cover 62 can be easily attached to the gear housing 2. It is like that.

In addition, in the said form, although the hole is provided in the cover, it is good also as a recessed part which the convex part by the side of a housing fits. In addition, the cover is not limited to the case where the hole is provided in the cover and the protrusion is provided in the housing. Of course, in addition to the uneven fitting, a locking structure using a hook or a screwing structure may be adopted.
In addition, the mode switching member has a disk shape in the above embodiment, but may have other shapes such as a lever shape. In this case, the design of the cover can be changed such that the cover is engaged with a constricted portion provided at the base of the lever portion to prevent the cover from coming off.
Further, the cover is not limited to a single one, but a mode switching member may be sandwiched between the split types as a pair of left and right halves.

In the above embodiment, the mode switching member is provided on the lower surface of the housing, but it may be provided on either the left or right side of the housing. In this case, the cover may be provided on the side surface side according to the position of the mode switching member, or may be provided so as to cover the lower surface and the side surface in consideration of support on the lower surface.
In addition, other forms of the hammer drill can be changed in design as appropriate. For example, the rotation / blow mechanism is configured such that the piston reciprocates in a fixed cylinder to link the batter, or the intermediate element is omitted. However, it is possible to appropriately change the configuration other than the above configuration, such as directly hitting the bit or adopting a crank mechanism for the reciprocating motion of the piston.

It is a partial longitudinal cross-sectional view of a hammer drill (drill mode). It is a cross-sectional view in a clutch part. It is explanatory drawing of a receiving plate, (A) is a perspective view, (B) is a side surface, (C) shows the AA line cross section, respectively. It is a side view of a hammer drill. It is a bottom view of a hammer drill.

Explanation of symbols

  1 .... hammer drill, 2 .... gear housing, 4 .... motor, 5 .... output shaft, 6 .... tool holder, 17 .... impact bolt, 23 ... piston cylinder, 25 ... striker, 26 ... intermediate Shaft, 31 ... second gear, 32 ... boss sleeve, 33 ... swash bearing, 34 ... connecting arm, 35 ... connecting piece, 36 ... receiving plate, 37 ... joint pin, 40 ... side plate, 42 .. Projection, 43 .. Coil spring, 45 .. Clutch, 47 .. Mounting part, 48 .. Mode switch knob, 49 .. Knob part, 50 .. Holding cylinder, 51 .. Engagement pin, 62. Cover, 63 ... hole, 64 ... circular convex part, 65 ... through hole.

Claims (3)

A hammer drill in which a mode switching member for switching an operation mode by an operation from outside the housing is attached to a housing in which a rotation / blow mechanism of a bit is installed,
The mode switching member mounting portion outer surface of the housing is provided with a cover that covers and covers the mode switching member except for its operation portion, and that forms an air layer between the housing and the housing. Hammer drill to do.   The hammer drill according to claim 1, wherein the mode switching member and a cover are provided on a lower surface of the housing.   The hammer according to claim 1 or 2, wherein the mounting of the cover is performed by fitting a convex portion provided on one of the housing and the cover and a concave portion or a hole provided on the other. Drill.

Images