JP2009241229A - Hammer drill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hammer capable of lengthening a service life of a switching member for changing over respective modes and downsizing a body. <P>SOLUTION: A piston 33, a hitting part 36 and an intermediate part 39 are provided in a cylinder 31 to strike a tip tool 50. A breathing hole 31b is formed on the cylinder 31, and a slide sleeve 41 sliding around a circumference of the cylinder is axially moved, thereby opening/closing the breathing hole 31b. The slide sleeve 41 is urged backward by a first spring 43 via a rotation locking member 37. The slide sleeve can be moved only by the switching member 44 and the first spring 43 provided on an outer frame member 30. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hammering tool such as a hammer or a hammer drill, and more particularly to a hammering tool that applies a hammering force and a rotational force to a tip tool.

  FIG. 11 shows a hammer drill as an example of a conventional impact tool. In the hammer drill having this structure, a cylinder 131 that is rotated by a rotational driving force transmission mechanism and can be fitted with a tip tool 150 is supported by a plurality of bearings in the outer frame member 130. The cylinder 131 has a hole 131a and a long hole 131b. At the rear of the cylinder 131, a bevel gear 128 that is rotatably arranged on the outer periphery of the cylinder 131 is provided. A connecting member 134 that can be engaged with the bevel gear 128 and is slidable with respect to the cylinder 131 and cannot rotate is provided in front of the bevel gear 128. On the inner periphery of the cylinder 131, an intermediate element 139 located behind the tip tool 150 is provided so as to be movable in the axial direction. A striker 136 is provided behind the intermediate element 139, and is arranged so as to be able to contact the intermediate element 139 at its front end.

  An annular member 151 slidably provided in the cylinder 131 and a pin 153 fitted thereto are provided at the rear portion of the meson 139. The pin 153 is movable along the long hole 131b. A holding sleeve 152 is slidably disposed on the outer periphery of the cylinder 131. The pin 153 can contact the holding sleeve 152. A slide sleeve 141 is disposed behind the holding sleeve 152 and is urged forward by a spring 142. The slide sleeve 141 is in contact with the holding sleeve 152 at the front portion. A rotation locking member 137 is supported by the outer frame member 130 and is in contact with the slide sleeve 141. A switching member 144 is rotatably provided on the upper part of the outer frame member 130. The switching member 144 has a cam portion 144b and an eccentric pin 144a. The cam portion 144b can push the rotation locking member 137, and the eccentric pin 144a can push the connecting member 134.

  A piston 133 is slidably mounted in the rear part of the cylinder 131. An air chamber 138 is defined by the piston 133 and the striker 136. The reciprocating motion of the piston 133 is transmitted to the striking element 136 through the air chamber 138 and is transmitted to the intermediate element 139 in contact with the striking element 136. Thereby, the striking force is transmitted to the tip tool 150.

  When the tip tool 150 is pressed against the work material, the intermediate member 139 contacting the tip tool 150 moves rearward, and the annular member 151 and the pin 153 holding the intermediate member 139 move backward. Then, the holding sleeve 152 and the slide sleeve 141 move backward against the biasing force of the spring 142. As a result, the slide sleeve 141 closes the hole 131a and the air chamber 138 is sealed, so that the striking force is transmitted to the tip tool 150.

When only the rotational force is applied to the tip tool 150, the switching member 144 is rotated to enter the rotation mode. Accordingly, the cam portion 144b moves forward, and the cam portion 144b pushes the rotation locking member 137 forward. Then, the slide sleeve 141 moves forward by the biasing force of the spring 142, and the hole 131a is always opened. Thereby, even if the piston 133 reciprocates, the striking force is not transmitted to the tip tool 150. At the same time, the connecting member 134 is retracted by the spring 142 and engaged with the bevel gear 128. The cylinder 131 rotates through the connecting member 134 and only the rotational force is applied to the tip tool 150. Such a conventional configuration is described in Patent Document 1.
JP2006-142459

  According to the prior art shown in FIG. 11, in the rotation mode, the reaction force of the impact received from the tip tool 150 is transmitted as indicated by the arrows in the figure. That is, it is transmitted from the tip tool 150 to the intermediate element 139 and transmitted to the annular member 151 that holds it. Then, it is transmitted to the switching member 144 via the pin 153 fitted to the annular member 151, the holding sleeve 152, the slide sleeve 141, and the rotation holding member 137. Therefore, in the structure in which the hole 131a is opened and closed by the movement of the meson 139, the reaction force from the tip tool 150 is directly received by the switching member 144, and the switching member 144 may be worn or damaged. Furthermore, with such a structure, the presence of the annular member 151, the pin 153, and the holding sleeve 152 is essential, and there are problems such as an increase in the number of parts and an increase in the overall tool length. Therefore, an object of the present invention is to provide a compact impact tool that does not transmit reaction force to the switching means, has a long life, and has a small number of parts.

  In order to achieve the above object, the present invention provides a housing, an electric motor accommodated in the housing, and a cylinder in which a breathing hole that is rotatably supported in the housing and communicates with the outside air is formed to hold a tip tool. A piston slidably provided on the inner periphery of the cylinder, a conversion mechanism for converting the rotation of the electric motor into a reciprocating motion of the piston, and transmitting the rotation of the electric motor to the cylinder. A rotation transmission mechanism that rotates about its axis, a striker that is reciprocally movable in the axial direction in the cylinder, and that defines an air chamber with the piston, and is disposed in the cylinder The rear end is struck by the striker, the tip is slidably held by the housing, and the first position for opening the breathing hole and the breathing hole are closed. Do A sleeve that is movable in the axial direction of the cylinder between two positions, a biasing member that is provided in the housing and biases the sleeve in the second position direction, and a part of the sleeve is exposed to the housing. Switching means for switching between a first position and a second position of the sleeve, and the sleeve is moved only by the switching means and the biasing member, and the sleeve is moved by the switching means. The air chamber communicates with the outside air through the breathing hole, and the sleeve is moved to the second position by the switching means so that the communication between the air chamber and the outside air is blocked. An impact tool is provided.

  And a connecting member which is held by the cylinder so as to be slidable between the first engaging position and the second engaging position in the axial direction of the cylinder and rotates together with the cylinder, and the switching means includes the connecting member. A holding portion that selectively holds the first engagement position and the second engagement position, and the rotation transmission mechanism includes a rotation transmission portion that is rotatable with respect to the cylinder. When in the first engagement position, it is desirable that the connecting member engages with the rotation transmitting portion to rotate the cylinder and is disengaged from the sleeve.

  The sleeve is provided so as to be movable and non-rotatable in the axial direction of the cylinder with respect to the housing. When the connecting member is in the second engagement position, the connecting member is engaged with the sleeve and It is desirable that the rotation transmitting portion is not rotatable and is not engaged with the rotation transmitting portion.

  In addition, when the sleeve is in the first position, the holding portion disengages the connecting member so as to cut off the engagement between the connecting member and the sleeve and the engagement between the connecting member and the rotation transmitting portion. It is desirable that the position can be regulated.

  According to the striking tool of the first aspect, the sleeve can be moved only by the switching means and the urging member rather than moving the sleeve via the intermediate element. Here, the reaction force of the tip tool is transmitted to the intermediate member striking the tip tool, the striker striking the rear end of the intermediate member, and the cylinder that holds them. The movement of the sleeve is irrelevant to the movement of the intermediate element, and the sleeve and the intermediate element are mechanically separated from each other, so that the reaction force of the tip tool does not act on the switching means via the intermediate element. Since the striker is slidable in the cylinder and defines the piston and the air chamber, the reaction force transmitted from the tip tool to the striker is absorbed by the air chamber. Also, since the sleeve moves in the axial direction on the cylinder, the reaction force of the tip tool, which is an axial force, does not act on the sleeve via the cylinder, and the reaction force of the tip tool is transmitted to the switching means via the sleeve. do not do. Therefore, the reaction force of the tip tool does not directly act on the switching unit. Thereby, damage to the switching means can be prevented and the life can be extended. Further, the structure of the impact tool can be simplified, the number of parts can be reduced, and the cost can be reduced. Furthermore, the overall length of the tool can be shortened, and a compact hammer drill can be obtained.

  In the impact tool according to claim 2, when the sleeve is in the first position by the switching means, the breathing hole communicates with the outside air, the air chamber is opened, and the impact force is not transmitted to the tip tool. At the same time, when the connecting member is held at the first engagement position by the holding portion of the switching means, the connecting member and the rotation transmitting portion are engaged to transmit the rotational force to the cylinder. Thereby, it becomes a rotation mode in which only the rotational force is applied to the tip tool. When the sleeve is in the second position by the switching means, the breathing hole is closed and the air chamber is sealed, and a striking force is applied to the tip tool via the striking element. At the same time, when the connecting member is held at the first engagement position by the holding portion of the switching means, the connecting member and the rotation transmitting portion are engaged to transmit the rotational force to the cylinder. Thereby, it becomes a rotation impact mode in which rotational force and impact force are given to a tip tool.

  In the impact tool according to claim 3, when the sleeve is in the second position by the switching means, the breathing hole is closed and the air chamber is sealed, and impact force is applied to the tip tool via the impactor. The At the same time, when the connecting member is held at the second engagement position by the holding portion of the switching means, the connecting member and the rotation transmitting portion are detached and the connecting member and the sleeve are engaged. Since the sleeve is not rotatable, the connecting member and the cylinder are also non-rotatable, and an impact mode in which only the impact force is applied to the tip tool is set.

  In the impact tool according to the fourth aspect, since the holding portion holds the connection member and the rotation transmitting portion so as to block the engagement, no rotational force is applied to the tip tool. Since the connecting member and the sleeve are detached, the cylinder can freely rotate. Further, since the sleeve is in the first position, the breathing hole is always open, and the striking force is not transmitted to the tip tool. As a result, a neutral mode is set in which neither the impact force nor the rotational force is applied to the tip tool, and the tip tool can also freely rotate. In the neutral mode, the sleeve is always in a state where the breathing hole is opened, so that the striking force is not transmitted to the tip tool even when the power is accidentally turned on. Such a structure can improve the safety of the impact tool.

  A striking tool according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing the entirety of a hammer drill 1 which is a typical striking tool, and a casing is constituted by a handle portion 10 serving as a rear housing, a motor housing 20, and an outer frame member 30 serving as a front housing. The The outer frame member 30 is provided with a tool holding portion 60 for detachably holding the tip tool 50. In the vicinity of the tool holding portion 60, the side handle 40 extends from the outer frame member 30 so as to be detachable. In the following description, the tip tool 50 side is the front, and the handle portion 10 side is the rear. Further, the direction in which the tip tool 50 extends is defined as the X direction, and the direction perpendicular to the direction (direction in which the handle 10 extends) is defined as the Y direction.

  A power cable 11 is attached to the handle portion 10 and a trigger 12 that can be operated by a user is attached. By connecting the power cable 11 to an external power source (not shown) and operating the trigger 12, the connection and disconnection of the power supply can be switched.

  The motor housing 20 is provided in front of the handle portion 10. Although the handle portion 10 and the motor housing 20 have separate structures, they can be made of plastic and integrally molded. The outer frame member 30 is located above and in front of the motor housing 20.

  A motor 21 is accommodated in the motor housing 20. The motor 21 includes a motor pinion shaft 22 and outputs a rotational driving force. A pinion 22 a is formed at the upper end of the motor pinion shaft 22. A first rotary shaft 23 and a second rotary shaft 24 are supported in parallel with the motor pinion shaft 22 via bearings around the axis. A first gear 25 that meshes with the pinion 22a is coaxially fixed to the lower portion of the first rotating shaft 23 in the Y direction. A first bevel gear 27 is formed on the upper portion of the first rotating shaft 23 in the Y direction, and meshes with a second bevel gear 28 described later. A second gear 26 that meshes with the pinion 22a is coaxially fixed to the lower portion of the second rotating shaft 24 in the Y direction. A crankshaft 29 is formed on the upper part of the second rotating shaft 24 in the Y direction so as to rotate concentrically with the second rotating shaft 24 having the same rotation center.

  A cylinder 31 extends in the X direction and is rotatably supported by a bearing fixed to the outer frame member 30. The cylinder 31 is formed with a first breathing hole 31a and a second breathing hole 31b. A tip tool 50 is detachably attached to the front of the cylinder 31.

  A piston 33 is disposed inside the cylinder 31 so as to be slidable in the axial direction of the cylinder 31. Connected to the piston 33 is a leading end portion of a connecting rod 35 that is rotatable about the Y direction as an axis. The rear end of the connecting rod 35 is connected to the crankshaft 29 so as to be rotatable about the Y direction. The second rotating shaft 24, the second gear 26, the crankshaft 29, and the connecting rod 35 constitute a conversion mechanism that converts the rotation of the electric motor 21 into the reciprocating motion of the piston 33.

  A striker 36 is provided so as to be movable in the axial direction of the cylinder 31 with a certain distance forward from the piston 33 in the cylinder 31 in the X direction. Further, the first breathing hole 31a described above is selectively opened and closed by the outer peripheral surface of the striker 36. A space surrounded by the striker 36, the piston 33, and the cylinder 31 is an air chamber 38, and the above-described second breathing hole 31b is positioned so as to open to the air chamber 38. An intermediate element 39 is disposed inside the cylinder 31 so as to be slidable in the axial direction. The rear end portion of the intermediate piece 39 can come into contact with the striker 36, and the strike force is transmitted to the intermediate piece 39 by the striker 36. The tip portion of the intermediate piece 39 can contact the rear portion of the tip tool 50, and the striking force is transmitted from the tip portion of the intermediate piece 39 to the tip tool 50. The tip tool 50 is held by a tool holding member 60 and a cylinder 31.

  A second bevel gear 28 that is rotatably supported by a holding member 32 fixed to the outer frame member 30 is provided at the rear portion of the cylinder 31 so as to be rotatable with respect to the cylinder 31. A spline engaging portion 28 a is formed on the front inner peripheral surface of the second bevel gear 28. The connecting member 34 is positioned in front of the second bevel gear 28 and is provided so as not to rotate with respect to the cylinder 31 and to be slidable in the axial direction. The connecting member 34 is provided with a spline groove 34a that can be engaged with the spline engaging portion 28a at the rear, and a tooth row 34b at the front. The first rotating shaft 23, the first gear 25, the first bevel gear 27, the second bevel gear 28, and the connecting member 34 transmit the rotation of the electric motor 21 to the cylinder 31 and rotate the cylinder 31 around its axis. The rotation transmission mechanism is configured.

  The rotation locking member 37 is slidable in the axial direction of the cylinder 31 with respect to the outer frame member 30, and is provided so as not to rotate. The rotation locking member 37 is urged rearward by the first spring 43, and a tooth row 37 a that can be engaged with the tooth row 34 b is formed on the inner peripheral surface of the rear portion of the rotation locking member 37. The rotation locking member 37 has a concavo-convex portion 37b on the outer peripheral surface side of the front portion thereof, and slides with respect to the outer frame member 30 by the concavo-convex portion 37b and is prevented from rotating with respect to the outer frame member 30.

  A slide sleeve 41 is slidably disposed on the outer peripheral surface of the cylinder 31 on the inner peripheral side of the rotation locking member 37. A flange portion 41A is provided on the front end surface of the slide sleeve 41, and is in contact with the rotation locking member 37 at the flange portion 41A. The slide sleeve 41 is biased forward by the second spring 42. Further, the second spring 42 urges the connecting member 34 rearward. Since the first spring 43 has a larger urging force than the second spring 42, the rotation locking member 37 is urged rearward against the second spring 42. The first breathing hole 31a and the second breathing hole 31b formed in the cylinder 31 are opposed to the inner peripheral surface of the slide sleeve 41, and the second breathing hole 31b is opened and closed by the axial movement of the slide sleeve 41. It has become. The first breathing hole 31 a is always in communication with the outside air through a gap 41 a provided between the slide sleeve 41 and the cylinder 31. An abutting portion 45 is provided on the outer periphery of the cylinder 31. The slide sleeve 41 is restricted from moving in the axial direction by the abutting portion 45.

  The switching member 44 is rotatably installed on the outer frame member 30 with a part thereof exposed. The switching member 44 has an eccentric pin 44a and a cam portion 44b. (See FIG. 10) By rotating the switching member 44, the eccentric pin 44 a pushes the connecting member 34 and slides the connecting member 34 in the axial direction of the cylinder 31. Further, the cam portion 44 b pushes the rotation locking member 37 and slides the rotation locking member 37 in the axial direction of the cylinder 31.

  Next, the operation of the hammer drill 1 will be described. The rotation output output from the motor 21 is transmitted to the first gear 25 by the pinion 22a. As the first gear 25 rotates, the first bevel gear 27 located on the same axis also rotates, and the second bevel gear 28 meshing with the first bevel gear 27 rotates. When the second bevel gear 28 and the connecting member 34 are engaged by the spline engaging portion 28 a and the spline groove portion 34 a, the rotational force is transmitted to the cylinder 31 through the connecting member 34. As a result, the tip tool 50 at the tip of the cylinder 31 rotates integrally with the cylinder 31. In this way, the rotational driving force is transmitted to the tip tool 50.

  The pinion 22 a is also meshed with the second gear 26, and the rotational force from the motor 21 is transmitted to the crankshaft 29 positioned coaxially with the second gear 26. The rotational motion is converted into a reciprocating motion by the crankshaft 29 and the connecting rod 35 connected to the crankshaft 29 and transmitted to the piston 33. In this state, when the tip tool 50 is pressed against the work material and the striker 36 is moved backward, the first breathing hole 31 a is blocked by the striker 36. When the second breathing hole 31b is blocked by the slide sleeve 41, the air chamber 38 is sealed. Then, the air in the air chamber 38 defined by the piston 33 and the striking element 36 is repeatedly compressed and expanded by the reciprocating motion of the piston 33, and reciprocating energy is applied to the striking element 36 through the air chamber 38. The striker 36 is in contact with the intermediate piece 39, and the intermediate piece 39 is in contact with the distal end tool 50 at the distal end portion, so that an impact force is applied to the distal end tool 50 through the intermediate piece 39.

  When the hammer drill 1 is operated with no load applied to the tip tool 50 or without the tip tool 50 attached, the rear end surface of the striker 36 passes through the first breathing hole 31a and opens the first breathing hole. Then, even if the second breathing hole 31b is in a closed state, the air chamber 38 communicates with the outside air through the first breathing hole 31a, and the striking force is not transmitted to the tip tool 50. In this way, the hammer drill 1 is prevented from being idle.

The hammer drill 1 can be switched between four modes: (1) impact / rotation mode, (2) impact mode, (3) rotation mode, and (4) neutral mode, by operating the switching member 44. Each mode will be described below.

(1) Impact / Rotation Mode The impact / rotation mode is shown in FIGS. 6 is a view of the switching member 44 of FIG. 2 as viewed from the motor side, and shows the positional relationship between the eccentric pin 44a and the cam portion 44b.

  In the impact / rotation mode, the eccentric pin 44a is in the position shown in FIG. 2, and the connecting member 34 is engaged with the spline engaging portion 28a by the spline groove portion 34a by the urging force of the second spring 42. Thereby, the rotation of the second bevel gear 28 is transmitted to the tip tool 50 via the connecting member 34 and the cylinder 31.

  The cam portion 44 b is not in contact with the rotation locking member 37, and the rotation locking member 37 is urged rearward by the first spring 43. Further, the urging force of the first spring 43 is transmitted to the slide sleeve 41 via the rotation locking member 37, and the slide sleeve 41 contacts the abutting portion 45. As a result, the second breathing hole 31b is closed and the air chamber 38 is sealed. In this state, when the striker 36 moves backward to close the first breathing hole 31a, a strike force is applied to the tip tool 50. In this way, both the striking force and the rotational force are applied to the tip tool 50 in the striking / rotating mode.

(2) Impact mode The impact mode is shown in FIGS. FIG. 7 is a view of the switching member 44 of FIG. 3 as viewed from the motor side, and shows the positional relationship between the eccentric pin 44a and the cam portion 44b. As shown in FIG. 7, when the switching member 44 is set in the hit mode, the eccentric pin 44a moves forward.

  The eccentric pin 44a pushes the connecting member 34 against the urging force of the second spring 42 and slides the connecting member 34 forward. As a result, the engagement between the spline engaging portion 28a and the spline groove portion 34a is released. Further, the tip of the connecting member 34 is inserted into the rotation holding member 37, whereby the tooth row 34b and the tooth row 37a are engaged. Since the rotation holding member 37 is prevented from rotating by the concavo-convex portion 37 b, the connecting member 34 engaged with the rotation holding member 37 also cannot be rotated. As a result, the cylinder 31 also cannot rotate, and the second bevel gear 28 idles on the cylinder 31, so that the rotational force is not transmitted to the tip tool 50.

  Since the slide sleeve 41 abuts against the abutting portion 45 and closes the second breathing hole 31b, the tip tool 50 is pressed against the work material and the striker 36 is moved backward to close the first breathing hole 31a. The air chamber 38 is sealed. As a result, the piston 33 reciprocates and an impact force is applied to the tip tool 50 via the air chamber 38. Thus, only the striking force is applied to the tip tool 50 in the striking mode.

(3) Neutral mode FIGS. 4 and 8 show the neutral mode. FIG. 8 is a view of the switching member 44 of FIG. 4 as viewed from the motor side, and shows the positional relationship between the eccentric pin 44a and the cam portion 44b. As shown in FIG. 8, when the switching member 44 is set to the neutral mode, the eccentric pin 44a and the cam portion 44b move forward.

  In the neutral mode, the eccentric pin 44a is in the position shown in FIG. 4, and the eccentric pin 44a pushes the connecting member 34 to slide the connecting member 34 forward against the urging force of the second spring 42. As a result, the engagement between the spline engaging portion 28a and the spline groove portion 34a is released. Then, the second bevel gear 28 idles on the cylinder 31 and no rotational force is transmitted to the tip tool 50.

  Further, the cam portion 44 b pushes the rotation locking member 37 and slides the rotation locking member 37 forward against the urging force of the first spring 43. Since the slide sleeve 41 is in contact with the rotation locking member 37 at the flange portion 41A, the slide sleeve 41 moves forward by the biasing force of the second spring 42 as the rotation locking member 37 advances. As a result, the second breathing hole 31b is opened, and the air chamber 38 communicates with the outside air. Even if the piston 33 reciprocates in this state, the pressure in the air chamber 38 does not fluctuate and the striking force is not transmitted to the tip tool 50. In this way, neither the striking force nor the rotational force is applied to the tip tool 50 in the neutral mode.

  In the neutral state, the rotation locking member 37 moves rearward and the tooth row 34b and the tooth row 37a are not engaged, so that the cylinder 31 can freely rotate. As a result, the tip tool 50 can be positioned in the rotational direction. For example, even when the tip tool 50 has a scoop-like directivity, the position of the tip tool in the rotational direction can be easily adjusted.

(4) Rotation mode A rotation mode is shown in FIG.5 and FIG.9. FIG. 9 is a view of the switching member 44 of FIG. 5 as viewed from the motor side, and shows the positional relationship between the eccentric pin 44a and the cam portion 44b. As shown in FIG. 9, the cam portion 44b moves forward by setting the switching member 44 to the rotation mode.

  In the rotation mode, the eccentric pin 44a is in the position shown in FIG. 5, and the connecting member 34 is engaged with the spline engaging portion 28a by the spline groove portion 34a by the urging force of the second spring 42. Thereby, the rotation of the second bevel gear 28 is transmitted to the tip tool 50 via the connecting member 34 and the cylinder 31.

  The cam portion 44 b pushes the rotation locking member 37 and slides the rotation locking member 37 forward against the urging force of the first spring 43. Since the slide sleeve 41 is in contact with the rotation locking member 37 at the flange portion 41 </ b> A, it moves forward by the biasing force of the second spring 42. As a result, the second breathing hole 31b is opened, and the air chamber 38 communicates with the outside air. Even if the piston 33 reciprocates in this state, the pressure in the air chamber 38 does not fluctuate and the striking force is not transmitted to the tip tool 50. In this way, only the rotational force is applied to the tip tool 50 in the rotation mode.

  By adopting a structure in which the rotation locking member 37 is moved only by the switching member 44 and the first spring 43 as in the present embodiment, the reaction force received from the tip tool 50 is transmitted as indicated by the arrows shown in FIG. That is, it is transmitted from the tip tool 50 to the cylinder 31 via the intermediate element 39. Thereby, it is possible to prevent the reaction force of the tip tool 50 from directly acting on the switching member 44.

  In addition, the impact tool by this invention is not limited to embodiment mentioned above, A various change is possible in the range of the summary of the invention described in the claim. For example, the rotation locking member and the slide sleeve can be molded as an integral sleeve. Further, the rotation transmission may be switched by detaching the connecting member, the sleeve, and the rotation transmission portion by using a tooth structure, a spline engagement portion, or the like as a clutch structure.

The whole perspective view which shows the whole impact tool by embodiment of this invention. Sectional drawing which shows the impact tool at the time of impact and rotation mode of the impact tool by embodiment of this invention Sectional drawing which shows the impact tool at the time of the impact mode of the impact tool by embodiment of this invention Sectional drawing which shows the impact tool at the time of the neutral mode of the impact tool by embodiment of this invention Sectional drawing which shows the impact tool at the time of rotation mode of the impact tool by embodiment of this invention, and represents the transmission path of the reaction force of a tip tool The figure which shows the switching member at the time of the impact / rotation mode of the impact tool by embodiment of this invention The figure which shows the switching member at the time of the impact mode of the impact tool by embodiment of this invention The figure which shows the switching member at the time of the neutral mode of the impact tool by embodiment of this invention The figure which shows the switching member at the time of the rotation mode of the impact tool by embodiment of this invention The figure which shows the shape of the switching member by embodiment of this invention Sectional drawing showing the conventional impact tool and showing the transmission path of the reaction force of the tip tool

Explanation of symbols

1: striking tool, 20: motor housing, 21: motor, 22: motor pinion shaft, 23: first rotating shaft, 24: second rotating shaft, 25: first gear, 26: second gear, 27: first Bevel gear, 28: second bevel gear, 29: crankshaft, 30: outer frame member, 31: cylinder, 31a: first breathing hole, 33: piston, 34: connecting member, 35: connecting rod, 36: striker, 37: Rotation locking member, 38: Air chamber, 39: Meson, 41: Slide sleeve, 42: Second spring, 43: First spring, 44: Switching member, 44a: Eccentric pin, 44b: Cam part, 50 : Tip tool

Claims (4)

A housing;
An electric motor housed in the housing;
A cylinder that is rotatably supported in the housing to hold the tip tool and is formed with a breathing hole that communicates with outside air;
A piston slidably provided on the inner periphery of the cylinder;
A conversion mechanism for converting the rotation of the electric motor into the reciprocating motion of the piston;
A rotation transmission mechanism for transmitting rotation of the electric motor to the cylinder and rotating the cylinder about its axis;
A striking element that is slidable in an axial direction in the cylinder and that defines an air chamber with the piston;
An intermediate element disposed in the cylinder, the rear end of which is struck by the striker, and the tip of which strikes the tip tool;
A sleeve slidably held in the housing and movable in an axial direction of the cylinder between a first position for opening the breathing hole and a second position for closing the breathing hole;
A biasing member provided in the housing and biasing the sleeve in the second position direction;
A switching means for switching between a first position and a second position of the sleeve, wherein a part of the sleeve is exposed;
The sleeve is moved only by the switching means and the biasing member,
By moving the sleeve to the first position by the switching means, the air chamber communicates with the outside air through the breathing hole, and by moving the sleeve to the second position by the switching means, the air A striking tool characterized in that communication between the room and outside air is blocked. A connecting member which is held by the cylinder so as to be slidable between the first engagement position and the second engagement position in the axial direction of the cylinder and rotates together with the cylinder;
The switching means has a holding portion that selectively holds the connecting member at the first engagement position and the second engagement position,
The rotation transmission mechanism has a rotation transmission portion that is rotatable with respect to the cylinder,
2. The connecting member according to claim 1, wherein when the connecting member is in the first engagement position, the connecting member is engaged with the rotation transmitting portion to rotate the cylinder and is not engaged with the sleeve. The hitting tool described in 1. The sleeve is movable relative to the housing in the axial direction of the cylinder and non-rotatable;
When the connecting member is in the second engagement position, the connecting member engages with the sleeve to make the cylinder unrotatable and disengaged from the rotation transmitting portion. Item 3. The impact tool according to item 2.   When the sleeve is in the first position, the holding portion restricts the position of the connecting member so as to interrupt the engagement between the connecting member and the sleeve and the engagement between the connecting member and the rotation transmitting portion. The striking tool according to claim 2, which is possible.

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