Impact tools

Abstract

To provide a technique contributing to miniaturization of an impact tool.SOLUTION: An impact tool includes a tool holder, a motor, a crank mechanism, a barrel part, and a crank housing. The tool holder has a cylindrical shape, and has a long axis. The tool holder is constituted to hold a tip tool inserted from the tip side so as to be linearly movable along the long axis. The barrel part stores the tool holder. The barrel part has a first screw part, and a first positioning part. The crank housing stores a crank mechanism. The crank housing has a second screw part, and a second positioning part. The barrel part and the crank housing are connected to each other by screw engagement of the first screw part and the second screw part around the long axis. The first positioning part and the second positioning part are configured to be brought into at least partial contact with each other around the long axis, and thereby position the barrel part and the crank housing with respect to the long axis.SELECTED DRAWING: Figure 2

Description

【Technical Field】 【0001】 The present disclosure relates to a percussion tool configured to perform a machining operation on a workpiece by striking a tip tool. 【Background Art】 【0002】 A percussion tool converts the rotational motion of a motor shaft into a linear motion and transmits it to a tip tool removably held in a tool holder, thereby driving the tip tool linearly along a drive shaft. Among the tool body of the percussion tool, a cylindrical portion that houses the tool holder and a portion that houses the motion conversion mechanism may be formed as separate parts and connected in an assembly process. For example, in the percussion tool (hammer drill) disclosed in Patent Document 1, a barrel portion that houses the tool holder and a crank housing that houses the motion conversion mechanism are connected by a plurality of bolts. More specifically, the bolt is tightened into the screw hole of the boss portion through the through hole of the flange portion while the rear surface of the flange portion provided at the rear end portion of the barrel portion abuts against the front surface of the boss portion provided at the front end portion of the crank housing. 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Japanese Unexamined Patent Application Publication No. 2014-124697 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 In the above-described percussion tool, in order to secure an area for tightening a plurality of bolts, the flange portion of the barrel portion protrudes radially outward compared to other portions. Therefore, the connecting portion between the barrel portion and the crank housing becomes large in the radial direction. 【0005】 In view of the above situation, one non-limiting object of the present disclosure is to provide a technique that contributes to miniaturization of a percussion tool. [Means for solving the problem] 【0006】 According to one non-limiting aspect of the present disclosure, a striking tool is provided configured to perform a machining operation on a workpiece by striking a cutting tool. The striking tool comprises a tool holder, a motor, a crank mechanism, a barrel section, and a crank housing. The tool holder is cylindrical and has a long axis. The tool holder is configured to hold a cutting tool inserted from the tip side so as to be linearly movable along the long axis. The motor has a motor shaft. The crank mechanism is operably connected to the motor shaft and is configured to convert the rotational motion of the motor shaft into linear motion along the long axis for driving the cutting tool. The barrel section houses the tool holder. The barrel section has a first threaded section and a first positioning section. The crank housing houses the crank mechanism. The crank housing has a second threaded section and a second positioning section. The barrel section and the crank housing are connected to each other by a screw engagement between the first threaded section and the second threaded section around the long axis. The first positioning section and the second positioning section are configured to position the barrel section and the crank housing relative to the long axis by at least partially contacting each other around the long axis. 【0007】 In this embodiment of the striking tool, the barrel and the crank housing are connected to each other in the longitudinal direction of the tool holder by screw engagement between the first threaded portion and the second threaded portion. Therefore, as in the conventional example, there is no need to extend the portion for connecting to the crank housing using a separate bolt on the radially outer side of the barrel portion. As a result, the radial dimensions of the connection portion between the barrel and the crank housing, and the overall mass of the striking tool can be reduced. In addition, the possibility of misalignment between the first threaded portion and the second threaded portion can be reduced between the first threaded portion and the second threaded portion. [Brief explanation of the drawing] 【0008】 [Figure 1] This is a cross-section of a hammer drill. [Figure 2]This is a magnified section of Figure 1. [Figure 3] This is a partial perspective view of a hammer drill with a portion of the outer housing removed. [Figure 4] Figure 2 shows a cross-sectional view along the line IV-IV (however, only the barrel section, the crank housing support section, and the rotation regulating mechanism are shown). [Figure 5] Figure 4 is a cross-sectional view along the VV line. [Modes for carrying out the invention] 【0009】 In one non-limiting embodiment of this disclosure, the first threaded portion may be a male threaded portion, and the second threaded portion may be a female threaded portion. In other words, the first threaded portion may include threads formed on the outer circumferential surface of the cylindrical portion of the barrel. The second threaded portion may include thread grooves formed on the inner circumferential surface defining the cylindrical bore of the crank housing. According to this embodiment, a barrel portion that is easier to accommodate a tool holder can be realized compared to the case in which the barrel portion is provided with a female threaded portion. 【0010】 In addition to the above embodiment, or in place of the above embodiment, the first positioning portion may include the outer circumferential surface of the barrel portion adjacent to the first threaded portion at the tip end in the longitudinal direction of the tool holder. The second positioning portion may include the inner circumferential surface of the crank housing adjacent to the second threaded portion at the tip end in the longitudinal direction. The outer circumferential surface and the inner circumferential surface may be configured to abut each other. In this embodiment, the outer circumferential surface at the tip end of the first threaded portion (male threaded portion) and the inner circumferential surface at the tip end of the second threaded portion (female threaded portion) abut each other and function as a positioning surface. This makes it possible to realize the first positioning portion and the second positioning portion with a simple configuration while effectively reducing the possibility of misalignment between the first threaded portion and the second threaded portion. 【0011】 In addition to or instead of the above embodiment, the first positioning part and the second positioning part may be lightly press-fitted to each other, at least partially. According to this embodiment, the first positioning part and the second positioning part can prevent the screw engagement between the first screw part and the second screw part from loosening due to the relative rotation of the barrel part and the crank housing. 【0012】 In addition to the above embodiment, or in place of the above embodiment, the outer circumference of the barrel portion may include two planes that are parallel to the long axis of the tool holder and parallel to each other. According to this embodiment, when connecting the barrel portion to the crank housing, the operator can easily rotate the barrel portion relative to the crank housing by gripping the two planes of the barrel portion with a tool for screw engagement of the first threaded portion and the second threaded portion. 【0013】 In addition to the above embodiment, or in place of the above embodiment, a sealing member may be placed between the first positioning part and the second positioning part. The first positioning part and the second positioning part have high dimensional accuracy and good inherent contact because they position the barrel part and the crank housing with respect to the long axis, but according to this embodiment, the contact between the first positioning part and the second positioning part can be further improved by placing a sealing member. 【0014】 In addition to or in lieu of the above embodiments, the striking tool may further include a rotation restricting mechanism configured to restrict the relative rotation of the barrel portion and the crank housing in a first direction that loosens the screw engagement between the first screw portion and the second screw portion. According to this embodiment, the connection between the barrel portion and the crank housing can be stably maintained. 【0015】 In addition to the above embodiment, or in place of the above embodiment, the rotation restricting mechanism may include a recess formed on the outer circumference of the barrel portion and an engaging member supported by the crank housing. The engaging member may be displaceable between an engagement position in which it engages with the recess and an engagement release position in which it does not engage with the recess. According to this embodiment, when the engaging member is in the engagement position, the connection between the barrel portion and the crank housing can be stably maintained. Furthermore, convenience is improved because, as needed, the barrel portion and the crank housing can be separated by relative rotation in the first direction simply by moving the engaging member to the engagement release position. 【0016】 In addition to or in lieu of the above embodiments, the recess and engaging member may be configured to allow relative rotation between the barrel and the crank housing by moving the engaging member from the engaged position to the disengaged position in response to the relative rotation of the barrel and the crank housing in a second direction opposite to the first direction. The recess and engaging member may also be configured to prevent relative rotation between the barrel and the crank housing by remaining in the engaged position when the barrel and the crank housing rotate relative to each other in the first direction. According to this embodiment, the recess and engaging member are configured to allow relative rotation between the barrel and the crank housing in the second direction, that is, the direction in which the screw engagement is tightened, thus facilitating the connection of the barrel and the crank housing. 【0017】 In addition to or instead of the above-described embodiment, the impact tool may further include a gripping portion extending in a direction intersecting the long axis. The gripping portion may have a first end portion and a second end portion located farther from the long axis of the tool holder than the first end portion in the extending direction of the gripping portion. In the extending direction of the gripping portion, the engaging member may be disposed on the same side as the second end portion with respect to the long axis. If the engaging member is provided on the opposite side of the second end portion of the gripping portion with respect to the long axis of the tool holder (i.e., the drive axis of the tip tool) in the extending direction of the gripping portion, the portion corresponding to the engaging member protrudes in the radial direction and is likely to be in the way during work. In contrast, according to this embodiment, the engaging member can be disposed at a position where it is less likely to be in the way during work. 【0018】 Hereinafter, with reference to FIGS. 1 to 5, the hammer drill 1 according to representative and non-limiting embodiments of the present disclosure will be specifically described. The hammer drill 1 is a non-limiting example of an "impact tool" according to the present disclosure. 【0019】 The hammer drill 1 is an example of an impact tool and is capable of striking a removably attached tip tool 91 and linearly driving it along the drive axis DX (hereinafter referred to as a striking operation). Further, the hammer drill 1 is also capable of rotationally driving the tip tool 91 around the drive axis DX (hereinafter referred to as a rotational operation). 【0020】 As shown in FIG. 1, the hammer drill 1 includes a tool body 10 and a handle housing 19 connected to the tool body 10. The tool body 10 of the present embodiment houses a tool holder 30 configured to removably hold the tip tool 91, a motor 2, and a drive mechanism 3 configured to drive the tip tool 91 by the power of the motor 2. 【0021】 The tool holder 30 is a long cylindrical member having a long axis. The tool holder 30 is configured to removably receive a part of the tip tool 91 and hold the tip tool 91 so as to be linearly slidable in the extending direction of the long axis and non-rotatable with respect to the tool holder 30. Hereinafter, of the two ends of the tool holder 30 in the long axis direction, the end on the side where the tip tool 91 is inserted is referred to as the tip, and the opposite end is referred to as the base end. Further, the tool holder 30 is supported by the tool body 10 so as to be rotatable about the long axis. Therefore, the tip tool 91 is rotatable about the long axis integrally with the tool holder 30. Thus, the long axis of the tool holder 30 defines the drive axis DX of the tip tool 91. 【0022】 The motor 2 of the present embodiment is a brushed motor. The motor 2 is driven by electric power supplied from an external AC power source via a power cord not shown. However, a brushless motor may be adopted for the motor 2. Further, the motor 2 may be driven by electric power supplied from a rechargeable battery. In the present embodiment, the motor 2 is arranged such that the rotation axis RX of the motor shaft 25 intersects (more specifically, is orthogonal to) the drive axis DX. 【0023】 The drive mechanism 3 is operably connected to the motor 2 and is driven by the power of the motor 2. The drive mechanism 3 of the present embodiment includes a crank mechanism 31 for impact operation and an impact element 33, and a rotation transmission mechanism 37 for rotation operation. 【0024】 The crank mechanism 31 is operably connected to the motor shaft 25 and is configured to convert the rotational movement of the motor shaft 25 into a linear movement (specifically, the linear movement of the piston 315) along the drive axis DX for driving the tip tool 91. 【0025】 More specifically, the crank mechanism 31 includes a crankshaft 311, a connecting rod 314, and a piston 315. The crankshaft 311 is operably connected to the motor shaft 25 and rotated by the motor shaft 25. The crankshaft 311 has an eccentric pin 313. The connecting rod 314 is operably connected to the eccentric pin 313 and the piston 315. The piston 315 is slidably housed in a cylinder 32. The cylinder 32 is coaxially connected to the tool holder 30. The piston 315 reciprocates within the cylinder 32 along the drive shaft DX in response to the drive of the motor 2. 【0026】 The striking element 33 is configured to move linearly in response to the reciprocating motion of the piston 315 and strike the tool tip 91. In this embodiment, the striking element 33 includes a striker 34 and an impact bolt 35. The striker 34 is slidably positioned within the cylinder 32. The impact bolt 35 is slidably positioned within the tool holder 30. An air chamber is formed between the striker 34 and the piston 315. Due to the pressure fluctuations generated in the air chamber as the piston 315 reciprocates, the striker 34 also reciprocates along the drive shaft DX. When the striker 34 collides with the impact bolt 35, the impact bolt 35 transmits kinetic energy to the tool tip 91. 【0027】 The rotation transmission mechanism 37 is operably connected to the motor shaft 25 and is configured to transmit the rotation of the motor shaft 25 to the tool holder 30. The cutting tool 91 held in the tool holder 30 is rotationally driven around the drive shaft DX in response to the rotation transmission mechanism 37 being driven. The rotation transmission mechanism 37 is a gear reduction mechanism with a well-known configuration. 【0028】 The hammer drill 1 of this embodiment can be selectively operated in either a hammering-only mode or a rotary hammering mode. In hammering-only mode, only the crank mechanism 31 and the hammering element 33 are driven, and only hammering is performed. In rotary hammering mode, the crank mechanism 31, the hammering element 33, and the rotation transmission mechanism 37 are driven, and hammering and rotational movements are performed simultaneously. Any known configuration may be used for switching between modes. Therefore, a description of such configurations will be omitted. 【0029】 The tool body 10 of this embodiment includes a barrel section 11, a crank housing 13, and a motor housing 15. The barrel section 11 is the part that houses the tool holder 30. The crank housing 13 is the part that houses the crank mechanism 31 and the rotation transmission mechanism 37. The motor housing 15 is the part that houses the motor 2. 【0030】 In this embodiment, the barrel portion 11, the crank housing 13, and the motor housing 15, each formed as separate components, are connected to each other to form a tool body 10 as an integrated housing. As will be described in detail later, the crank housing 13 is connected to the base end of the barrel portion 11 in the extending direction of the drive shaft DX (the end opposite to the end where the tip tool 91 is held). The motor housing 15 is connected to the crank housing 13 by screws and protrudes from the crank housing 13 in a direction substantially perpendicular to the drive shaft DX. In other words, the tool body 10 in this embodiment is formed in an L-shape when viewed in a direction perpendicular to the drive shaft DX and the rotation axis RX of the motor shaft 25. 【0031】 For convenience, in the following explanation, the direction of extension of the drive shaft DX (the long axis direction of the tool holder 30) is defined as the front-to-back direction of the hammer drill 1. In the front-to-back direction, the direction from the base end to the tip of the tool holder 30 is defined as the front direction of the hammer drill 1, and the direction from the tip to the base end is defined as the rear direction. In addition, the direction of extension of the rotation axis RX of the motor shaft 25 (which is also the direction of extension of the gripping portion 193 described later) is defined as the up-and-down direction of the hammer drill 1. In the up-and-down direction, the direction from the motor 2 towards the drive shaft DX is defined as the up direction, and the direction from the drive shaft DX towards the motor 2 is defined as the down direction. The direction perpendicular to the drive shaft DX and the rotation axis RX is defined as the left-to-right direction of the hammer drill 1. 【0032】 The handle housing 19 includes an outer housing portion 191 that partially covers the tool body 10 and a gripping portion 193 that is gripped by the user. The outer housing portion 191 is configured to substantially cover the barrel portion 11 and the crank housing 13 of the tool body 10. The gripping portion 193 extends vertically so as to intersect (more specifically, substantially perpendicular to) the drive shaft DX. The upper end of the gripping portion 193 is connected to the rear end of the outer housing portion 191. The lower end of the gripping portion 193 is connected to the rear end of the motor housing 15. The gripping portion 193 is provided with a switch lever 195 that is pressed by the user. A switch 196 for starting the motor 2 is housed inside the gripping portion 193. When the switch 196 is turned on in response to the pressing operation of the switch lever 195, the motor 2 is driven. 【0033】 The following describes the details of the connection structure between the barrel section 11 and the crank housing 13. 【0034】 As shown in Figure 1, the barrel portion 11 is formed in a cylindrical shape with a larger diameter than the tool holder 30. The tool holder 30 is coaxially positioned within the barrel portion 11 and is rotatably supported by bearings 301 and 302 located within the barrel portion 11. 【0035】 As shown in Figure 2, the barrel portion 11 has a first threaded portion 120 and a first positioning portion 121. More specifically, the rear end of the barrel portion 11 is formed as a cylindrical portion 110. The first threaded portion 120 is a male threaded portion provided on the rear half of the cylindrical portion 110. That is, the first threaded portion 120 has threads formed on the outer circumferential surface of the rear half of the cylindrical portion 110. The first positioning portion 121 is the front half of the cylindrical portion 110. That is, the first positioning portion 121 is provided adjacent to the front side of the first threaded portion 120 and coaxially with the first threaded portion 120. An annular groove 124 is formed in the first positioning portion 121, and an annular sealing member 125 (for example, an O-ring) is fitted into it. 【0036】 Furthermore, as shown in Figures 2 and 3, a flange portion 115 is provided on the front side of the cylindrical portion 110 (first positioning portion 121) of the barrel portion 11. The flange portion 115 is an annular portion that protrudes radially outward from the cylindrical portion 110. The rear surface 116 of the flange portion 115 is connected to the front end of the first positioning portion 121 and extends radially outward. The rear surface 116 is a plane substantially perpendicular to a straight line extending in the front-rear direction. The outer diameter of the flange portion 115 is set to be substantially equal to the outer diameter of the front end portion 130 of the crank housing 13, which will be described later. 【0037】 Furthermore, a tool engagement portion 117 is provided on the front side of the flange portion 115 of the barrel portion 11. The tool engagement portion 117 is formed in a generally hexagonal shape when viewed from the front. In other words, the tool engagement portion 117 has three pairs of planar portions that are parallel to the drive shaft DX and parallel to each other. 【0038】 As shown in Figure 1, the crank housing 13 is a hollow member that houses the crank mechanism 31 and the rotation transmission mechanism 37. Of the crank mechanism 31, the crankshaft 311 is supported by the crank housing 13 via a bearing 312. The rear end of the cylinder 32 that houses the piston 315 is also supported by the crank housing 13 via a bearing 321. 【0039】 As shown in Figure 2, the crank housing 13 has a second threaded portion 140 and a second positioning portion 141. The second threaded portion 140 is a female threaded portion provided at the front end portion 130 of the crank housing 13. More specifically, the front end portion 130 of the crank housing 13 has a cylindrical bore 131. The second threaded portion 140 has a screw groove formed in the rear half portion of the inner circumferential surface that defines the cylindrical bore 131. The second positioning portion 141 is the front half portion of the front end portion 130 (the portion corresponding to the front half portion of the cylindrical bore 131). In other words, the second positioning portion 141 is provided adjacent to the front side of the second threaded portion 140 and coaxially with the second threaded portion 140. 【0040】 In this embodiment, the barrel portion 11 and the crank housing 13 are connected to each other by the screw engagement of the first threaded portion 120 and the second threaded portion 140 around the drive shaft DX. Hereinafter, the entirety of the first threaded portion 120 and the second threaded portion 140 of the tool body 10 in the state of mutual engagement will also be referred to as the screw engagement portion. 【0041】 Furthermore, the first threaded portion 120 and the second threaded portion 140 are screwed in until the rear surface 116 of the flange portion 115 of the barrel portion 11 contacts the front end surface 133 of the front end portion 130 of the crank housing 13 in the front-rear direction. In other words, the rear surface 116 and the front end surface 133 function as positioning surfaces that define the front-rear position of the barrel portion 11 and the crank housing 13. 【0042】 Furthermore, the first positioning section 121 and the second positioning section 141 contact each other (area contact) around the drive shaft DX, thereby positioning the barrel section 11 and the crank housing 13 relative to the drive shaft DX. More specifically, the outer circumferential surface 122 (cylindrical surface) of the first positioning section 121 and the inner circumferential surface 142 (surface defining the cylindrical hole 131) of the second positioning section 141 function as positioning surfaces. These positioning surfaces contact each other (area contact) around the drive shaft DX, thereby positioning the barrel section 11 and the crank housing 13 relative to the drive shaft DX. Hereinafter, the entirety of the first positioning section 121 and the second positioning section 141 in contact with each other within the tool body 10 will also be referred to as the positioning section. 【0043】 In this embodiment, the positioning portion is configured such that in the first region R1 behind the annular groove 124, the outer circumferential surface 122 of the first positioning portion 121 and the inner circumferential surface 142 of the second positioning portion 141 are in sliding contact, and in the second region R2 in front of the annular groove 124, the first positioning portion 121 and the second positioning portion 141 are lightly press-fitted with each other. More specifically, the outer diameter of the portion of the first positioning portion 121 of the barrel portion 11 in front of the annular groove 124 is set to be slightly larger than the outer diameter of the portion behind it. The diameter of the cylindrical bore 131 of the crank housing 13 is substantially uniform and is set to be approximately equal to the outer diameter of the portion of the first positioning portion 121 in rear of the annular groove 124. 【0044】 In the process of connecting the barrel portion 11 to the crank housing 13, the operator inserts the rear end (cylindrical portion 110) of the barrel portion 11 into the cylindrical hole 131 of the front end 130 of the crank housing 13 and screws the first threaded portion 120 into the second threaded portion 140. At this time, the operator can easily rotate the barrel portion 11 relative to the crank housing 13 by gripping a pair of parallel planar portions of the tool engagement portion 117 with the tool. As the screwing progresses, the portion of the first positioning portion 121 behind the annular groove 124 enters the second positioning portion 141, with its outer circumferential surface 122 sliding against the inner circumferential surface 142 of the second positioning portion 141. As the screwing progresses further, the portion of the first positioning portion 121 in front of the annular groove 124 enters the second positioning portion 141 while being lightly press-fitted. When the rear surface 116 of the flange portion 115 of the barrel portion 11 comes into contact with the front end surface 133 of the front end portion 130 of the crank housing 13, the coupling process is completed. 【0045】 Furthermore, the hammer drill 1 of this embodiment is equipped with a rotation restricting mechanism 7 configured to restrict the relative rotation of the barrel portion 11 and the crank housing 13 in a direction that loosens the screw engagement between the first screw portion 120 and the second screw portion 140 (hereinafter referred to as the loosening direction). 【0046】 As shown in Figures 3 to 5, the rotation restricting mechanism 7 comprises a plurality of recesses 71 formed on the outer circumference of the flange portion 115 of the barrel portion 11, and an engaging member 73 rotatably supported by the crank housing 13. The engaging member 73 has a hook-shaped tip. The engaging member 73 is rotatably supported around a pivot axis extending in the front-rear direction by a pin 74 fixed to a support portion 135 provided on the front end portion 130 of the crank housing 13. The engaging member 73 is rotatable between an engagement position (shown by a solid line in Figure 4) in which the tip of the engaging member 73 engages with any of the recesses 71, and an engagement release position (shown by a dotted line in Figure 4) in which it does not engage with any of the recesses 71. 【0047】 The engaging member 73 is biased toward the flange portion 115 by the biasing member 75. In this embodiment, the biasing member 75 is a torsion coil spring. The coil portion of the biasing member 75 is arranged around the pin 74, with one end 751 of the biasing member 75 locked to the front end 130 and the other end 752 locked to the engaging member 73. In this way, the biasing member 75 biases the engaging member 73 toward the engagement position. Note that the biasing member 75 may be changed to another type of spring instead of a torsion coil spring. 【0048】 The rotation restricting mechanism 7 of this embodiment is configured to allow the barrel portion 11 to rotate only in the tightening direction (the direction in which the screw engagement between the first screw portion 120 and the second screw portion 140 tightens, the direction of the arrow TD in Figure 4) relative to the crank housing 13, opposite to the loosening direction (arrow LD direction in Figure 4). More specifically, the rotation restricting mechanism 7 is configured as a ratchet mechanism, and the flange portion 115 in which the recess 71 is formed functions as a ratchet gear 70, and the engaging member 73 functions as a pawl that cooperates with the ratchet gear 70. As the barrel portion 11 and the crank housing 13 rotate relative to each other in the tightening direction, the engaging member 73 disengages from the recess 71 and rotates to the disengagement position, thereby enabling relative rotation between the barrel portion 11 and the crank housing 13. On the other hand, when the barrel portion 11 and the crank housing 13 rotate relative to each other in the loosening direction, the engaging member 73 remains in the engaged position and maintains engagement with the recess 71, thereby preventing relative rotation between the barrel portion 11 and the crank housing 13. 【0049】 As described above, in the hammer drill 1 of this embodiment, the barrel portion 11 and the crank housing 13 are connected to each other in the front-rear direction by screw engagement between the first threaded portion 120 and the second threaded portion 140. Therefore, as in the conventional example, there is no need to provide an extension portion on the radially outer side of the barrel portion 11 for connecting the barrel portion 11 and the crank housing 13 using a separate bolt. As a result, the radial dimension of the connection portion between the barrel portion 11 and the crank housing 13 can be reduced. This makes it easier for the operator to auxiliaryly hold the barrel portion 11 and the connection portion between the barrel portion 11 and the crank housing 13. Furthermore, it is possible to prevent an increase in mass due to the enlargement of the barrel portion 11 and the crank housing 13. 【0050】 Furthermore, the barrel section 11 and the crank housing 13 can be connected solely by the screw engagement between the first threaded section 120 and the second threaded section 140. This reduces the number of parts and simplifies the connection process compared to using multiple bolts. 【0051】 Furthermore, in this embodiment, since the first threaded portion 120 of the barrel portion 11 is a male threaded portion, the entire space within the barrel portion 11 can be used relatively freely as a housing space for the tool holder 30. Therefore, a bearing 302 that supports the rear end of the tool holder 30 is fitted inside the rear end of the barrel portion 11 (more specifically, radially inward of the positioning portion). 【0052】 With only screw engagement between the first threaded portion 120 and the second threaded portion 140, misalignment between the first threaded portion 120 and the second threaded portion 140 is possible. In this case, the support of the tool holder 30 and the cylinder 32 may become unstable. In contrast, in the hammer drill 1, the first positioning portion 121 and the second positioning portion 141 abut each other around the long axis (drive shaft DX) of the tool holder 30, thereby reducing the possibility of misalignment between the first threaded portion 120 and the second threaded portion 140. In particular, in this embodiment, the outer circumferential surface 122 (positioning surface) of the first positioning portion 121 and the inner circumferential surface 142 (positioning surface) of the second positioning portion 141 can position the barrel portion 11 and the crank housing 13 over the entire circumference of the drive shaft DX, which is effective. 【0053】 Furthermore, in this embodiment, the first threaded portion 120 (thread) and the first positioning portion 121 (positioning surface) are each provided adjacent to each other on the outer circumference of the cylindrical portion 110 of the barrel portion 11. The second threaded portion 140 (thread groove) and the second positioning portion 141 (positioning surface) are each provided adjacent to each other on the inner circumference of the front end portion 130 of the crank housing 13. This realizes a simple and rational configuration for the threaded engagement portion and positioning portion. 【0054】 Furthermore, in the hammer drill 1, vibration occurs in the tool body 10 during operation in both the impact-only mode and the rotary impact mode. This vibration can cause relative rotation between the barrel 11 and the crank housing 13. Also, during chipping work in impact-only mode, the user may rotate the hammer drill 1 relative to the tip tool 91, which can cause relative rotation between the barrel 11 and the crank housing 13. 【0055】 In contrast, the first positioning portion 121 and the second positioning portion 141 in this embodiment are lightly press-fitted to each other in the second region R2 in front of the annular groove 124. This reduces the possibility of the barrel portion 11 and the crank housing 13 rotating relative to each other and the screw engagement between the first threaded portion 120 and the second threaded portion 140 loosening. Furthermore, since the hammer drill 1 is equipped with a rotation restricting mechanism 7, it prevents the screw engagement between the first threaded portion 120 and the second threaded portion 140 from loosening and can stably maintain the connection between the barrel portion 11 and the crank housing 13. 【0056】 Furthermore, rotation restriction by light press-fitting is preferable because it can be effective in both directions (loosening and tightening). On the other hand, the rotation restriction mechanism 7 (ratchet mechanism) can provide a more reliable rotation restriction effect than light press-fitting, but only in one direction (loosening direction). In this embodiment, these two types of structures can effectively restrict the relative rotation between the barrel portion 11 and the crank housing 13. 【0057】 In particular, the rotation restricting mechanism 7 of this embodiment is a ratchet mechanism that prohibits relative rotation of the barrel portion 11 and the crank housing 13 in the loosening direction, but allows rotation in the tightening direction. Therefore, the operator can screw the first threaded portion 120 into the second threaded portion 140 regardless of the rotation restricting mechanism 7, making the connection work between the barrel portion 11 and the crank housing 13 easy. Furthermore, for example, during disassembly and repair, the operator can separate the barrel portion 11 and the crank housing 13 by rotating them relative to each other in the loosening direction simply by rotating the engaging member 73 to the release position. 【0058】 The above embodiments are merely illustrative, and the impact tools relating to this disclosure are not limited to the illustrated hammer drill 1. For example, modifications as illustrated below can be made. Furthermore, at least one of these modifications may be adopted in combination with the hammer drill 1 illustrated in the embodiments and at least one of the features described in each claim. 【0059】 The impact tool according to this disclosure only needs to be capable of performing machining operations on a workpiece by striking the tip tool 91, and may be embodied, for example, as an electric hammer (demolition hammer, scraper) capable only of impacting. It may also be embodied as a hammer drill having an impact-only mode, a rotational impact mode, and a rotation-only mode in which only rotational motion is performed. The configuration of the drive mechanism 3 can be appropriately changed depending on or regardless of the type of impact tool, as long as it includes a crank mechanism that converts the rotational motion of the motor shaft into linear motion. 【0060】 The configuration of the tool body 10 and / or the handle housing 19 (e.g., shape, components, connection method) can be modified as appropriate. For example, the tool body 10 may have a shape other than L-shape in side view, and the rotation axis RX of the motor shaft 25 does not necessarily have to be perpendicular to the drive axis DX. Also, for example, instead of the handle housing 19, both ends of a U-shaped handle including a gripping portion may be connected to the tool body. Alternatively, at least one outer housing portion with a configuration different from the above embodiment may be connected to the gripping portion. 【0061】 The first screw portion 120 and the first positioning portion 121 may be separated from each other in the front-rear direction, or they may be in different positions in the radial direction of the barrel portion 11. Similar modifications are possible for the second screw portion 140 and the second positioning portion 141. Furthermore, the first positioning portion 121 and the second positioning portion 141 do not necessarily need to be in contact with the entire circumference of the drive shaft DX, but may be in partial contact at multiple points around the drive shaft DX. 【0062】 The rotation restricting mechanism according to this disclosure is not limited to the rotation restricting mechanism 7 (ratchet mechanism) exemplified in the embodiments. The shape, number, arrangement, etc., of the recess 71 and the engaging member 73 are merely examples and can be changed as appropriate. For example, instead of the engaging member 73 (pawl), a leaf spring having a protrusion that can engage with the recess 71 provided on the outer circumference of the flange portion 115 may be used. The rotation restricting mechanism may be configured to hinder not only the loosening direction but also the relative rotation of the barrel portion 11 and the crank housing 13 in the tightening direction. For example, the shape of the recess 71 may be changed to also hinder relative rotation in the tightening direction. For example, the engaging member may be linearly movable. Also, for example, the rotation restricting mechanism may be a fastener that engages with the barrel portion 11 and the crank housing 13 when the first screw portion 120 and the second screw portion 140 are screwed to a predetermined position. 【0063】 In view of the spirit of the present invention and the embodiments described above, the following embodiments are constructed. At least one of the following embodiments may be adopted in combination with the features of the embodiments and their modifications, or at least one of the features described in each claim. [Aspect 1] The crank housing houses a cylinder coaxially connected to the tool holder, The crank mechanism is operably connected to the motor shaft and includes a crankshaft supported by the crank housing, The system may also include a piston that is operably connected to the crankshaft and is slidable within the cylinder. [Aspect 2] The first threaded portion includes threads formed on the outer circumferential surface of the cylindrical portion of the barrel, The first positioning portion includes, of the outer circumferential surface, a portion adjacent to the screw threads on the tip side in the longitudinal axis direction of the tool holder, The second threaded portion includes a thread groove formed on the inner circumferential surface that defines the cylindrical bore of the crank housing, The second positioning portion includes the portion of the inner circumferential surface that is adjacent to the screw groove on the tip side in the longitudinal direction. [Aspect 3] The first positioning portion and the second positioning portion are configured such that their outer circumferential surface and inner circumferential surface abut each other over the entire circumference of the long axis. [Aspect 4] The first positioning portion and the second positioning portion include a first region in which the outer circumferential surface and the inner circumferential surface are in slidable contact with each other, and a second region that is lightly press-fitted with each other. The second region is located on the tip side relative to the first region in the longitudinal direction of the tool holder. [Aspect 5] The rotation restricting mechanism includes a biasing member that biases the engaging member toward the engaging position. [Aspect 6] The rotation restricting mechanism is configured as a ratchet mechanism comprising a ratchet gear and a pawl. [Explanation of Symbols] 【0064】 1: Hammer drill, 10: Tool body, 11: Barrel section, 110: Cylindrical section, 115: Flange section, 116: Rear surface, 117: Tool engagement section, 120: First threaded section, 121: First positioning section, 122: Outer surface, 124: Annular groove, 125: Seal member, 13: Crank housing, 130: Front end, 131: Cylindrical hole, 133: Front end surface, 135: Support section, 140: Second threaded section, 141: Second positioning section, 142: Inner surface, 15: Motor housing, 19: Handle housing, 191: Outer housing section, 193: Gripping section, 195: Switch lever, 196: Switch, 2: Mo 25: Motor shaft, 3: Drive mechanism, 30: Tool holder, 301: Bearing, 302: Bearing, 31: Crank mechanism, 311: Crankshaft, 312: Bearing, 313: Eccentric pin, 314: Connecting rod, 315: Piston, 32: Cylinder, 321: Bearing, 33: Striking element, 34: Striker, 35: Impact bolt, 37: Rotation transmission mechanism, 7: Rotation regulating mechanism, 70: Ratchet gear, 71: Recess, 73: Engaging member, 74: Pin, 75: Biasing member, 91: Tip tool, 751: End, 752: End, R1: First area, R2: Second area,

Claims

[Claim 1] A striking tool configured to perform machining operations on a workpiece by striking the tip of the tool, A cylindrical tool holder having a long axis, configured to hold a tip tool inserted from the tip side so that it can move linearly along the long axis, A motor having a motor shaft, A crank mechanism operably connected to the motor shaft and configured to convert the rotational motion of the motor shaft into linear motion along the long axis for driving the tip tool, A barrel portion for housing the tool holder, comprising a barrel portion having a first threaded portion and a first positioning portion, A crank housing for housing the aforementioned crank mechanism, comprising a crank housing having a second threaded portion and a second positioning portion, The barrel portion and the crank housing are connected to each other by screw engagement between the first threaded portion and the second threaded portion around the long axis. The first positioning portion and the second positioning portion are configured to position the barrel portion and the crank housing relative to the long axis by at least partially contacting each other around the long axis. The striking tool is characterized in that the first positioning portion and the second positioning portion are lightly press-fitted with each other, at least partially. [Claim 2] The striking tool according to claim 1, The first threaded portion is a male threaded portion, The striking tool is characterized in that the second threaded portion is a female threaded portion. [Claim 3] The striking tool according to claim 2, The first positioning portion includes the outer circumferential surface of the portion of the barrel portion adjacent to the first threaded portion at the tip side in the longitudinal axis direction of the tool holder. The second positioning portion includes the inner circumferential surface of the portion of the crank housing adjacent to the second threaded portion at the tip side in the longitudinal direction, A striking tool characterized in that the outer circumferential surface and the inner circumferential surface are configured to abut each other. [Claim 4] A striking tool according to any one of claims 1 to 3, A striking tool characterized in that a sealing member is disposed between the first positioning portion and the second positioning portion. [Claim 5] A striking tool according to any one of claims 1 to 3, A striking tool further comprising a rotation restricting mechanism configured to restrict the relative rotation of the barrel portion and the crank housing in a first direction that loosens the screw engagement between the first screw portion and the second screw portion. [Claim 6] The striking tool according to claim 5, The aforementioned rotation control mechanism is The recess formed on the outer circumference of the barrel portion, A striking tool characterized by including an engaging member supported by the crank housing and displaceable between an engaging position in which it engages with the recess and an unengaged position in which it does not engage with the recess. [Claim 7] The striking tool according to claim 6, The impact tool is characterized in that the recess and the engaging member are configured such that, as the barrel portion and the crank housing rotate relative to each other in a second direction opposite to the first direction, the engaging member moves from the engaged position to the disengaged position, thereby enabling relative rotation between the barrel portion and the crank housing, and when the barrel portion and the crank housing rotate relative to each other in the first direction, the engaging member remains in the engaged position, thereby preventing relative rotation between the barrel portion and the crank housing. [Claim 8] The striking tool according to claim 6, A gripping portion extending in a direction intersecting the long axis, further comprising a gripping portion having a first end and a second end located further from the long axis than the first end in the direction of extension of the gripping portion, The striking tool is characterized in that, in the extending direction of the gripping portion, the engaging member is positioned on the same side as the second end with respect to the long axis. [Claim 9] A striking tool configured to perform a machining operation on a workpiece by striking the tip tool, A cylindrical tool holder having a long axis, configured to hold a tip tool inserted from the tip side so that it can move linearly along the long axis, A motor having a motor shaft, A crank mechanism operably connected to the motor shaft and configured to convert the rotational motion of the motor shaft into linear motion along the long axis for driving the tip tool, A barrel portion for housing the tool holder, comprising a barrel portion having a first threaded portion and a first positioning portion, A crank housing for housing the aforementioned crank mechanism, comprising a crank housing having a second threaded portion and a second positioning portion, The barrel portion and the crank housing are connected to each other by screw engagement between the first threaded portion and the second threaded portion around the long axis. The first positioning portion and the second positioning portion are configured to position the barrel portion and the crank housing relative to the long axis by at least partially contacting each other around the long axis. The striking tool is characterized in that the outer circumference of the barrel portion includes two planes that are parallel to the long axis and parallel to each other.