Impact tool

Abstract

An impact tool is provided. The impact tool has a tool body, a motor, a handle, at least one force applying member, and at least one elastic member. The handle is connected to the tool body in a manner capable of moving in at least a front-rear direction. The handle includes a cover portion covering a portion of the tool body, and a grip portion connected to the cover portion and extending in a direction intersecting a driving axis. The at least one force applying member is interposed between the tool body and the handle, and applies a force to the tool body and the handle in a direction in which the tool body and the handle are moved away from each other in the front-rear direction. The at least one elastic member is interposed between the tool body and the cover portion of the handle. The at least one elastic member is movable relative to the tool body and the handle and is capable of undergoing a shear deformation with relative movement of the tool body and the handle. Accordingly, vibration transmitted to the handle is reduced in the impact tool.

Description

Technical Field

[0001] This application relates to an impact tool configured as a linearly driven tip tool. Background Technology

[0002] In impact tools that machine workpieces by driving the tip tool in a straight line along the drive axis, particularly large vibrations occur in the direction of the drive axis. Various vibration-damping housing structures have been proposed to address this. For example, in the impact tool (hammer drill) disclosed in Patent Document 1, the handle including the grip and the main body housing the motor and drive mechanism are elastically connected by vibration-damping rubber. Existing technical documents Patent documents

[0003] Patent Document 1: Japanese Patent Publication No. 2011-000684 Summary of the Invention [The technical problem to be solved by this invention]

[0004] In the impact tool disclosed in Patent Document 1, vibrations in the extension direction of the drive shaft can be effectively suppressed from being transmitted from the main body to the handle by the shear deformation of the anti-vibration rubber. On the other hand, further improvements are expected in reducing vibrations transmitted to the handle.

[0005] The purpose of this application is to provide a solution that improves upon existing techniques for reducing vibrations transmitted to the handle in impact tools. [Technical solutions used to solve technical problems]

[0006] According to one aspect of this application, an impact tool is provided, which is configured to drive a tip tool in a straight line along a predetermined front-to-back direction via a drive axis. The impact tool includes a tool body, a motor, a handle, at least one force-applying component, and at least one elastic component.

[0007] The tool body extends along a drive axis. A motor is housed within the tool body. A handle is connected to the tool body in a manner that allows it to move at least in the forward-backward direction. The handle includes a cover and a gripping portion. The cover covers a portion of the tool body. The gripping portion is connected to the cover and extends in a direction intersecting the drive axis. At least one force-applying member is located between the tool body and the handle. The at least one force-applying member applies force to the tool body and the handle in a direction that moves them away from each other in the forward-backward direction. At least one elastic member is located between the tool body and the cover of the handle. The at least one elastic member is movable relative to the tool body and the handle and is capable of shear deformation as the tool body and the handle move relative to each other. Furthermore, the term "capable of shear deformation" here includes not only the case where only shear deformation occurs, but also the case where shear deformation accompanied by compressive deformation occurs.

[0008] According to the above structure, as vibrations occur during the driving of the top tool, the handle moves relative to the tool body in the front-back direction (the extension direction of the drive axis), and at least one force-applying component absorbs the vibrations in the front-back direction, thereby reducing the transmission of vibrations from the tool body to the handle. Furthermore, at least one elastic component can also reduce the transmission of vibrations to the handle through shear deformation. Moreover, at least one elastic component can move relative to the tool body and the handle in the front-back direction, thereby smoothly guiding the relative movement of the tool body and the handle. Attached Figure Description

[0009] Figure 1 This is the left view of the hammer drill, showing the handle in its initial position. Figure 2 This is the rear view of the hammer drill. Figure 3 This is a left view of a hammer drill with the left side of the handle removed, showing the handle in its initial position. Figure 4 yes Figure 1 Sectional view IV-IV. Figure 5 yes Figure 2 VV sectional view. Figure 6 This is the left view of the hammer drill, showing the handle in the front position. Figure 7 This is a left view of a hammer drill with the left side of the handle removed, showing the handle in the front position. Figure 8 Is with Figure 4 The corresponding sectional view shows the handle in the forward position. Figure 9 Is with Figure 5 The corresponding sectional view shows the handle in the forward position. Explanation of reference numerals in the attached figures 1: Hammer drill; 2: Tool body; 21: Drive mechanism housing; 23: Motor housing; 23L: Left side; 23R: Right side; 231: Front end; 25: First spring receiving part; 251: Protrusion; 252: Abutment surface; 29: Corrugated part; 3: Handle; 3L: Left side component; 3R: Right side component; 31: Cover; 31L: Left wall; 31R: Right wall; 33: Holding part; 331: Trigger; 335: Switch; 337: Power cord; 35: Second spring receiving part; 351: Base; 352: Abutment surface ; 354: Protrusion; 41: Force-applying component; 411: First end; 412: Second end; 5: Guide portion; 5F: Front guide portion; 5R: Rear guide portion; 51: First ball retainer portion; 52: First recess; 53: Second ball retainer portion; 54: Second recess; 55: Elastic component; 55F: Front elastic component; 55R: Rear elastic component; 71: Motor; 711: Motor shaft; 713: Fan; 75: Drive mechanism; 79: Tool holder; 91: Top tool; A1: Drive axis; A2: Rotation axis. Detailed Implementation

[0010] In one or more embodiments of this application, at least one elastic member may be configured such that, during the movement of the handle relative to the tool body in the back-and-forth direction within a predetermined range, it does not substantially undergo shear deformation while moving in the back-and-forth direction relative to both the tool body and the handle, and undergoes shear deformation as the handle moves beyond the predetermined range relative to the tool body. According to this structure, as the relative movement of the handle relative to the tool body exceeds the predetermined range, at least one elastic member, in addition to at least one force-applying member, exerts a vibration reduction effect through shear deformation. Therefore, vibration transmission is effectively reduced in accordance with the magnitude of the vibration in the back-and-forth direction.

[0011] In one or more embodiments of this application, at least one elastic member may be formed in a spherical shape. According to this structure, an elastic member that is not easily damaged even when subjected to shear forces can be achieved.

[0012] In one or more embodiments of this application, at least one elastic member may be capable of rolling relative to the tool body and the handle in the front-back direction. According to this structure, the relative movement of the tool body and the handle in the front-back direction can be guided particularly smoothly, thereby achieving an elastic member that is not easily worn.

[0013] In one or more embodiments of this application, at least one elastic member may be capable of shear deformation as the tool body and handle move relative to each other in the vertical direction, wherein the vertical direction is orthogonal to the front-back direction and corresponds to the extension direction of the grip. According to this structure, in addition to vibrations in the front-back direction, the transmission of vibrations in the vertical direction can be effectively reduced.

[0014] In one or more embodiments of this application, at least one elastic member may include two elastic members, which are symmetrically arranged with respect to a plane including the drive axis and extending along the extension direction of the handle. According to this structure, compared to the case of providing one elastic member, the relative movement of the tool body and the handle in the front-rear direction can be guided more stably, and the vibration damping effect can also be improved.

[0015] In one or more embodiments of this application, at least one elastic member may include at least one front elastic member and at least one rear elastic member. Alternatively, at least one rear elastic member may be positioned in the front-rear direction closer to the grip than at least one front elastic member. According to this structure, at least one front elastic member and at least one rear elastic member can more stably guide the relative movement of the tool body and handle in the front-rear direction from different positions.

[0016] In one or more embodiments of this application, the elastic deformation characteristics of at least one front elastic member and at least one rear elastic member may be different from each other. Furthermore, elastic deformation characteristics can also refer to the ease or difficulty of elastic deformation. According to this structure, by appropriately setting the elastic deformation characteristics of the elastic members, one of at least one front elastic member and at least one rear elastic member can be used as a fulcrum for the relative rotation of the tool body and the handle.

[0017] In one or more embodiments of this application, at least one front elastic member may be configured to be less prone to elastic deformation than at least one rear elastic member. According to this structure, using at least one front elastic member located further from the handle as a fulcrum for relative rotation can effectively reduce the transmission of vibrations in the relative rotation direction between the tool body and the handle to the handle.

[0018] In one or more embodiments of this application, at least one force-applying component may include two force-applying components, which are symmetrically arranged relative to the axis of the output shaft in a plane including the axis of the motor's output shaft. According to this structure, compared to the case of providing only one force-applying component, the relative movement of the tool body and the handle in the front-rear direction can be stabilized.

[0019] <Example> Below, refer to Figures 1-9 The hammer drill 1 according to a representative and non-limiting embodiment of this application will be described. The hammer drill 1 is an example of an electric tool (so-called impact tool) capable of driving the tip tool 91 in a linear manner by impacting it. More specifically, the hammer drill 1 is an electric tool capable of performing an action of driving the tip tool 91 in a linear manner along a predetermined drive axis A1 (hereinafter also referred to as impact action) and an action of driving the tip tool 91 to rotate about the drive axis A1 (hereinafter referred to as rotation action).

[0020] like Figure 1 As shown, the outer contour of the hammer drill 1 is mainly formed by the tool body 2 and the handle 3 which is elastically connected to the tool body 2.

[0021] The tool body 2 is a hollow body that houses the main mechanism of the hammer drill 1, and is also referred to as the main body shell, outer contour shell, etc. The tool body 2 extends along the drive axis A1 of the top tool 91. A tool holder 79 is disposed in one end of the tool body 2 in the extension direction of the drive axis A1 (hereinafter referred to as the drive axis direction). The top tool 91 can be detachably mounted on the tool holder 79. The tool body 2 mainly houses a motor 71 and a drive mechanism 75, which is configured to drive the top tool 91 held in the tool holder 79 by the power of the motor 71. In this embodiment, the motor 71 is configured such that the rotation axis A2 of the motor shaft 711, which rotates integrally with the rotor, extends parallel to the drive axis A1.

[0022] The handle 3 is separately formed from the tool body 2 and is connected to the tool body 2 in a manner that allows it to move relative to the tool body 2 at least along the drive axis direction. The handle 3 has a grip portion 33 configured for the user to hold. The grip portion 33 extends from the other end of the tool body 2 in the drive axis direction (i.e., the end opposite to the end where the tool holder 79 is disposed) in a direction intersecting the drive axis A1 (specifically, a direction substantially orthogonal to the drive axis A1 and the rotation axis A2). The protruding end of the grip portion 33 is a free end. The grip portion 33 has a trigger 331 that is pressed (pulled) by the user. In the hammer drill 1, in response to the pressing operation of the trigger 331, the motor 71 is energized, the drive mechanism 75 is driven, and an impact action and / or rotation action is performed accordingly.

[0023] The detailed structure of the hammer drill 1 will now be described. For convenience, in the following description, the extension direction of the drive axis A1 (the long axis direction of the tool body 2) will be defined as the front-rear direction of the hammer drill 1. In the front-rear direction, the side where the tool holder 79 is located will be defined as the front side of the hammer drill 1, and the opposite side (the side where the grip 33 is located) will be defined as the rear side. The direction orthogonal to the drive axis A1 and corresponding approximately to the extension direction of the grip 33 (the direction orthogonal to both the drive axis A1 and the rotation axis A2) will be defined as the vertical direction of the hammer drill 1. In the vertical direction, the base end of the grip 33 will be defined as the upper side of the hammer drill 1, and the free end of the grip 33 will be defined as the lower side of the hammer drill 1. Furthermore, the direction orthogonal to both the front-rear and vertical directions will be defined as the left-right direction of the hammer drill 1.

[0024] First, the structure and internal construction of the tool body 2 will be explained.

[0025] The tool body 2 includes a drive mechanism housing 21 and a motor housing 23.

[0026] like Figure 1 As shown, the drive mechanism housing 21 is a hollow body that houses the drive mechanism 75. The drive mechanism housing 21 constitutes the front half of the tool body 2. The front end of the drive mechanism housing 21 is cylindrical, and a tool holder 79 is disposed inside it. The portion of the drive mechanism housing 21 other than the front end is formed into a generally rectangular cylindrical shape. The drive mechanism 75 includes a motion conversion mechanism for performing impact actions and an impact mechanism, and a rotation transmission mechanism for performing rotational actions. Since these are well-known structures, detailed illustrations and descriptions are omitted. The motion conversion mechanism typically employs a mechanism that converts rotational motion into linear motion using a swash bearing (e.g., a wobble plate / bearing) or a crankshaft mechanism and piston. The rotation transmission mechanism typically employs a reduction gear mechanism comprising multiple gears.

[0027] In this embodiment, the hammer drill 1 has three operating modes: impact mode (hammering only), rotation mode (rotation only), and rotating impact mode (hammering with rotation). The drive mechanism 75 operates according to the operating mode selected by the user via the mode switching knob. Since these are well-known structures, detailed illustrations and descriptions are omitted.

[0028] like Figure 1 , Figure 3 and Figure 4As shown, the motor housing 23 is a hollow body that houses the motor 71. The motor housing 23 is formed as a cylindrical shape with a closed rear end. In this embodiment, the motor housing 23 is a single component (a component without joints) formed separately from the drive mechanism housing 21. The motor housing 23 is connected and fixed to the rear end of the drive mechanism housing 21 by screws (not shown), forming the rear half of the tool body 2.

[0029] In this embodiment, the motor 71 is an AC motor with a commutator. A fan 713 is fixed to the portion of the motor shaft 711 that extends in the front-rear direction and protrudes forward of the stator. The fan 713 is disposed within the front end portion 231 of the motor housing portion 23. The front end portion 231 of the motor housing portion 23 protrudes radially outward of the stator than most of the portion extending rearward of the front end portion 231 (the portion that houses the stator, etc.) (specifically, the portion other than the first ball retainer 51 described later).

[0030] Furthermore, in this embodiment, two first spring receiving portions (spring seats) 25 (see reference 25) are provided in the motor housing 23 of the tool body 2 as a structure for elastically connecting the tool body 2 and the handle 3. Figure 5 ) and 4 first ball retainers 51 (see reference) Figure 4 The elastic connection structure between the tool body 2 and the handle 3 will be described in detail later.

[0031] Next, the structure and internal components of the handle 3 will be explained.

[0032] like Figures 2-4 As shown, in this embodiment, the handle 3 is formed by connecting and fixing the left-side component (left-side housing, left-side handle portion) 3L and the right-side component (right-side housing, right-side handle portion) 3R to each other in the left-right direction at multiple locations with screws (not shown). Furthermore, the handle 3 includes a cover portion 31 and a grip portion 33.

[0033] like Figures 1-4 As shown, the cover 31 is formed as a cylindrical shape with a closed rear end. The cover 31 covers the rear of the tool body 2, and more specifically, covers most of the motor housing 23. The cover 31 includes a left wall portion 31L, a right wall portion 31R, an upper wall portion, a lower wall portion, and a rear wall portion respectively disposed on the left, right, upper, lower, and rear sides of the motor housing 23. In addition, the central portion in the vertical direction of the left wall portion 31L and the right wall portion 31R protrudes forward from the other portions. In addition, the portion of the rear of the tool body 2 not covered by the cover 31 is covered by a corrugated portion 29. The corrugated portion 29 is configured to extend and retract in the front-rear direction as the tool body 2 moves relative to the handle 3.

[0034] In addition, in this embodiment, two second spring bearing portions (spring seats) 35 are provided on the cover portion 31 as a structure for elastically connecting the tool body 2 and the handle 3 (see reference). Figure 5 ) and 4 second ball retainers 53 (see reference) Figure 4 The second spring receiving part 35 is connected to the first spring receiving part 25 via the force-applying member 41. Furthermore, the second ball retaining part 53 is connected to the first ball retaining part 51 via a spherical (ball-shaped) elastic member 55. The connection structure between the tool body 2 and the handle 3 will be described in detail later.

[0035] like Figure 3 As shown, the grip portion 33 is formed into an elongated cylindrical shape. The grip portion 33 extends downward from the cover portion 31 in a cantilever shape. That is, the grip portion 33 extends vertically below the lower end of the tool body 2. A trigger 331 is disposed at the upper end of the grip portion 33. Inside the grip portion 33, a switch 335 is disposed behind the trigger 331. The switch 335 is normally kept in the off state and is turned on in response to the pressing operation of the trigger 331. In response to the switch 335 being turned on, the motor 71 is energized. In addition, a power cord 337 for connecting to an external AC power source extends from the lower end of the grip portion 33 (the free end, protruding end of the handle 3).

[0036] The following is a detailed explanation of the connection structure between the tool body 2 and the handle 3.

[0037] First, the connection structure between the first spring receiving part 25 and the second spring receiving part 35 will be explained.

[0038] like Figure 5 As shown, two first spring receiving portions (spring seats) 25 are provided at the front end portion 231 of the motor housing portion 23 of the tool body 2. More specifically, one of the two first spring receiving portions 25 is provided at the lower left rear end portion of the front end portion 231. The other of the two first spring receiving portions 25 is provided at the upper right rear end portion of the front end portion 231. More specifically, the two first spring receiving portions 25 are arranged on an imaginary plane P1 (see reference). Figure 2 The two first spring supports 25 are symmetrically arranged relative to the rotation axis A2, wherein the plane P1 includes the rotation axis A2 of the motor shaft 711 and extends from the lower left to the upper right when viewed from the rear. That is, the two first spring supports 25 are located at different positions in the vertical and horizontal directions, but at approximately the same position in the front-back direction. In addition, the distance between the rotation axis A2 of the motor shaft 711 and each of the two first spring supports 25 is approximately the same.

[0039] The first spring receiving portion 25 is configured to receive the first end 411 of the two ends of the force-applying member 41 (aggregating against the first end 411). In this embodiment, the force-applying member 41 is a compression coil spring. More specifically, the first spring receiving portion 25 has a protrusion 251 protruding rearward from the rear end face of the front end portion 231. The first end 411 of the force-applying member 41 is fitted onto the protrusion 251 of the first spring receiving portion 25 and abuts against the abutting surface 252 of the rear end face of the front end portion 231 (shoulder portion), which serves as the motor housing portion 23.

[0040] Two second spring receiving portions 35 are respectively provided corresponding to the two first spring receiving portions 25 of the tool body 2. More specifically, one of the two second spring receiving portions 35 is located at the lower left center of the cover portion 31, and the other of the two second spring receiving portions 35 is located at the upper right center of the cover portion 31. More specifically, the two second spring receiving portions 35 are arranged on plane P1 (refer to...). Figure 2 The first springs are arranged symmetrically with respect to the rotation axis A2. Furthermore, two second spring receiving portions 35 are respectively positioned directly behind the two first spring receiving portions 25. That is, the second spring receiving portions 35 are arranged on a straight line passing through the first spring receiving portions 25 and parallel to (extending in the front-rear direction) the rotation axis A2 of the motor shaft 711.

[0041] The second spring receiving portion 35 is configured to receive the second end portion 412 of the two ends of the force-applying member 41 (agreed upon by the second end portion 412). More specifically, the second spring receiving portion 35 has a base portion 351 protruding into the interior of the cover portion 31 and a protrusion 354 protruding forward from the base portion 351. The second end portion 412 of the force-applying member 41 is fitted onto the protrusion 354 and abuts against the abutting surface 352, which serves as the front end face of the base portion 351.

[0042] In this way, the first spring receiving part 25 and the second spring receiving part 35 are elastically connected by the force-applying member 41. The force-applying member 41 is held in a compressed state between the first spring receiving part 25 and the second spring receiving part 35, applying force to the tool body 2 and the handle 3 in a direction that moves them away from each other in the front-rear direction. That is, the force-applying member 41 applies force to the tool body 2 and the handle 3 in the forward and rearward directions, respectively.

[0043] Next, the connection structure between the first ball retainer 51 and the second ball retainer 53 will be described.

[0044] like Figure 3 and Figure 4As shown, of the four first ball bearing holders 51, two are located on the left side portion 23L of the motor housing 23, and two are located on the right side portion 23R. More specifically, on the left side portion 23L, two first ball bearing holders 51 are separated in the front-rear direction. On the right side portion 23R, two first ball bearing holders 51 are also separated in the front-rear direction. Furthermore, the two first ball bearing holders 51 on each of the left side portion 23L and the right side portion 23R are located at the front and rear ends of the portion of the motor housing 23 covered by the cover portion 31 of the handle 3 in the front-rear direction. In addition, the two first ball bearing holders 51 are substantially positioned at the same location in the vertical direction. In other words, when viewed from the side (when viewing the tool body 2 from the left or right), the two first ball bearing holders 51 are arranged in a straight line extending in the front-rear direction. In this embodiment, the two first ball bearing holders 51 are arranged on the rotation axis A2 of the motor shaft 711 when viewed from the side.

[0045] Additionally, the front pair of left and right first ball retaining portions 51 of the four first ball retaining portions 51 are positioned relative to an imaginary plane P2 (see reference). Figure 2 The hammer drill 1 (tool body 2) is symmetrically arranged, wherein the plane P2 passes through the center in the left-right direction of the hammer drill 1 (tool body 2) and extends in the up-down direction (the actual extending direction of the holding part 33). The plane P2 can also be referred to as an imaginary plane including the drive axis A1 and extending in the up-down direction (the plane including the drive axis A1 and the rotation axis A2). Similarly, the left and right pairs of first ball retaining parts 51 on the rear side are also symmetrically arranged with respect to the plane P2.

[0046] Each first ball retainer 51 has a first recess 52. All four first recesses 52 are recesses with depth in the left-right direction and have substantially the same structure. Specifically, each first recess 52 is recessed from the left side portion 23L or the right side portion 23R of the motor housing 23 towards the right or left side (towards plane P2), and is longer in the front-rear direction. The left-right depth and vertical width of the first recess 52 are set to be slightly smaller than the diameter of the elastic member 55. The front-rear length of the first recess 52 is set to be larger than the diameter of the elastic member 55. The first recess 52 is defined by a curved surface. The cross-sectional shape of the first recess 52 orthogonal to the drive axis A1 is arc-shaped, substantially matching approximately half of the outer surface of the elastic member 55, but detailed illustrations are omitted. Additionally, as... Figure 4 As shown, the front and rear ends of the first recess 52 are defined by curved surfaces that match approximately one-quarter of the elastic member 55.

[0047] Four second ball bearing retainers 53 correspond to four first recesses 52 of the tool body 2, with two provided on the left wall 31L and two on the right wall 31R of the cover 31. More specifically, two second ball bearing retainers 53 are provided separately in the front-rear direction on the left wall 31L of the cover 31. Similarly, two second ball bearing retainers 53 are provided separately in the front-rear direction on the right wall 31R. Furthermore, the two second ball bearing retainers 53 on each of the left wall 31L and the right wall 31R are substantially positioned at the same location in the vertical direction. In other words, when viewed from the side (when viewing the handle 3 from the left or right side), the two second ball bearing retainers 53 are positioned on a straight line extending in the front-rear direction (more specifically, on the rotation axis A2 of the motor shaft 711).

[0048] Additionally, the front pair of left and right second ball retainers 53 of the four second ball retainers 53 are positioned relative to plane P2 (see reference). Figure 2 Symmetrical configuration. Similarly, the pair of second recesses 54 on the rear side are also symmetrically configured with respect to plane P2.

[0049] Each second ball retainer 53 has a second recess 54. All four second recesses 54 are recesses with depth in the left-right direction and have substantially the same structure. Specifically, each second recess 54 is a recess that is recessed from the left wall portion 31L or the right wall portion 31R of the cover portion 31 to the left or right (in the direction away from the plane P2) and is longer in the front-back direction. The second recesses 54 are oriented opposite to the first recesses 52 in the left-right direction, but have substantially the same structure (length, width, curvature) as the first recesses 52.

[0050] like Figure 4 As shown, the elastic member 55 is disposed between each of the first ball retaining portion 51 and the second ball retaining portion 53 in the left-right direction, elastically connecting the first ball retaining portion 51 and the second ball retaining portion 53. The elastic member 55 is a ball (ball) formed of vibration-damping rubber (e.g., acrylonitrile butadiene rubber (NBR)). The left side portion 23L of the motor housing portion 23 and the left wall portion 31L of the cover portion 31 are held apart from each other in the left-right direction (non-contact state) by the elastic member 55. Similarly, the right side portion 23R of the motor housing portion 23 and the right wall portion 31R of the cover portion 31 are held apart from each other in the left-right direction (non-contact state) by the elastic member 55.

[0051] Furthermore, the elastic member 55 is disposed on the tool body 2 and the handle 3 in a manner that allows it to move in the front-back direction. More specifically, the elastic member 55 is capable of rolling in the front-back direction within the first recess 52 and the second recess 54 along the surfaces (curved surfaces) of the first recess 52 and the second recess 54. On the other hand, the rolling of the elastic member 55 in the vertical direction within the first recess 52 and the second recess 54 is restricted. The elastic member 55 guides the relative movement of the tool body 2 and the handle 3 in the front-back direction by rolling in the front-back direction within the first recess 52 and the second recess 54. Therefore, the first ball retaining part 51 (first recess 52), the second ball retaining part 53 (second recess 54), and the elastic member 55 will be collectively referred to as guide parts 5 below. In this embodiment, four guide parts 5 are provided, two on each of the left and right sides of the hammer drill 1.

[0052] Furthermore, below, when collectively referred to as the four guide portions 5, and when referring to at least one of the four guide portions 5 without distinction, they are simply referred to as guide portions 5. When referring to at least one of the front left and right pair of guide portions 5 among the four guide portions 5, they are called front guide portions 5F, and when referring to at least one of the rear left and right pair of guide portions 5, they are called rear guide portions 5R. Additionally, when collectively referred to as the four elastic members 55, and when referring to at least one of the four elastic members 55 without distinction, they are simply referred to as elastic members 55. When referring to the elastic member 55 of the front guide portion 5F among the four elastic members 55, it is called front elastic member 55F, and when referring to the elastic member 55 of the rear guide portion 5R, it is called rear elastic member 55R.

[0053] In this embodiment, all four elastic components 55 are made of the same type of rubber, but the elastic deformation characteristics (ease of elastic deformation) of the front elastic component 55F and the rear elastic component 55R are different. More specifically, the front elastic component 55F is configured to be less prone to elastic deformation than the rear elastic component 55R. Specifically, the front elastic component 55F is made of rubber with a higher hardness (harder) than the rear elastic component 55R.

[0054] As described above, the force-applying component 41 applies force to the tool body 2 and handle 3 in a direction away from each other (i.e., forward and backward) in the front-back direction. Therefore, in the initial state, the handle 3 is held in a position where each guide portion 5 is held by the loading force of the force-applying component 41, with the elastic component 55 partially abutting (embedded) against the rear end of the first recess 52 and the front end of the second recess 54. Figure 3 and Figure 4The position shown is referred to below as the initial position. When the handle 3 is in the initial position, the elastic member 55 is subjected to a force primarily in the shear direction from the first ball retainer 51 and the second ball retainer 53 through the surfaces defining the first recess 52 and the second recess 54. Furthermore, the force in the shear direction includes a force in the direction of linear shearing or a force in the direction of torsion. In this embodiment, the loading force of the force-applying member 41 is set to such that, in the initial state, the elastic member 55 undergoes extremely minor shear deformation.

[0055] On the other hand, when an external force is applied in the front-back direction to bring the tool body 2 and handle 3 closer together (e.g., the pressure applied when a user presses the tip tool 91 against the workpiece), such as Figures 6-9 As shown, the handle 3 compresses the force-applying member 41 (resisting the loading force of the force-applying member 41) while moving forward relative to the tool body 2 from its initial position. At this time, the rear end of the second ball retainer 53 abuts against the elastic member 55 from the rear, causing the elastic member 55 to roll forward within the first recess 52. When the handle 3 reaches the position where the elastic member 55 partially abuts (embeds) against the front end of the first recess 52 and the rear end of the second recess 54... Figure 7 and Figure 8 Before the position shown (hereinafter referred to as the forward position), the elastic member 55 rolls without undergoing shear deformation. When the handle 3 is positioned in the forward position, the elastic member 55 mainly bears the force in the shear direction from the first ball retainer 51 and the second ball retainer 53. When the tool body 2 and the handle 3 move relative to each other in the front-back direction towards a direction closer to each other, the elastic member 55 is subjected to a greater shear force and undergoes shear deformation. With the shear deformation of the elastic member 55, the handle 3 can move relative to the tool body 2 to a foremost position that is further forward than the forward position.

[0056] In addition, when the tool body 2 and the handle 3 move relative to each other in the left and right direction, the elastic member 55 is compressed and deformed by the force in the compression direction mainly from the first ball retaining part 51 and the second ball retaining part 53.

[0057] Furthermore, when the tool body 2 and handle 3 move relative to each other in the vertical direction, the elastic member 55 mainly bears the force in the shear direction from the first ball retainer 51 and the second ball retainer 53, thereby undergoing shear deformation. At this time, in this embodiment, the handle 3 can substantially rotate relative to the tool body 2 with the left and right front guides 5F (more specifically, the front elastic members 55F) as fulcrums. More specifically, as described above, the front elastic members 55F of the front guides 5F are harder than the rear elastic members 55R of the rear guides 5R and are not easily elastically deformed. That is, the rear elastic members 55R are more easily elastically deformed than the front elastic members 55F. Therefore, when an external force is applied that causes the tool body 2 and handle 3 to move relative to each other in the vertical direction, the handle 3 can substantially rotate relative to the tool body 2 with the left and right front elastic members 55F as fulcrums, while causing greater shear deformation of the rear elastic members 55R. The same applies when an external force is applied that causes the tool body 2 and handle 3 to rotate relative to each other about an axis extending in the left and right direction.

[0058] The functions of the tool body 2 and handle 3 during the impact action are explained below.

[0059] When the drive mechanism 75 performs an impact action, the top tool 91 is driven along the drive axis A1, generating maximum vibration in the drive axis direction (front-back direction) of the tool body 2. With this vibration, the tool body 2 and handle 3 move relative to each other in the front-back direction. As described above, during the movement of the handle 3 relative to the tool body 2 within a predetermined range between the initial position and the forward position, the elastic member 55 rolls in the front-back direction within the first recess 52 and the second recess 54 in each guide portion 5. During this period, the force-applying member 41 extends and retracts with the relative movement of the tool body 2 and the handle 3, thereby reducing vibration transmission to the handle 3. Furthermore, when the handle 3 moves relative to the tool body 2 between the forward position and the foremost position, in addition to the extension and retraction of the force-applying member 41, the shear deformation of the elastic member 55 also effectively reduces vibration transmission to the handle 3. Thus, in this embodiment, the extension and retraction of the force-applying member 41, the rolling of the elastic member 55, and the shear deformation effectively reduce vibration transmission corresponding to the magnitude of the vibration in the front-back direction.

[0060] Furthermore, the tool body 2 and handle 3 can move smoothly relative to each other in the front-back direction by the elastic member 55 rolling within the first recess 52 and the second recess 54. In particular, in this embodiment, the two pairs of guide portions 5 (a pair of left and right front guide portions 5F and a pair of left and right rear guide portions 5R) are separately arranged in the front-back direction, thus stably guiding the relative movement of the tool body 2 and handle 3 in the front-back direction. In addition, the elastic member 55 is spherical, so it is not easily damaged even when subjected to shear forces from the first ball retainer 51 and the second ball retainer 53, and it can roll, thus having the advantage of being resistant to wear.

[0061] Furthermore, in this embodiment, the elastic member 55 not only elastically deforms with the relative movement of the tool body 2 and the handle 3 in the front-to-back direction, but also elastically deforms with the relative movement of the tool body 2 and the handle 3 in the direction intersecting the drive axis A1. More specifically, the elastic member 55 undergoes shear deformation with the relative movement of the tool body 2 and the handle 3 in the vertical direction, and compressive deformation with the relative movement of the tool body 2 and the handle 3 in the horizontal direction. During the impact action, vibrations in the tool body 2 occur in other directions (e.g., vertical and horizontal directions) that are not as large as those in the front-to-back direction. The connection structure using the elastic member 55 of this embodiment can appropriately cope with vibrations in all directions other than the front-to-back direction as the elastic member 55 undergoes elastic deformation (shear deformation, compressive deformation).

[0062] Furthermore, in the drive mechanism 75, when a swinging component (e.g., swash bearing, wobble plate / bearing) is used in the motion conversion mechanism, vibrations occur in the vertical direction that are not as large as those in the front-back direction but are larger than those in the horizontal direction. The shear stiffness of the vibration damping rubber is lower than its compressive stiffness. That is, the elastic member 55 has the characteristic that its vibration reduction effect based on shear deformation is higher than its vibration reduction effect based on compressive deformation. In this embodiment, this characteristic is effectively utilized by employing a structure in which the elastic member 55 undergoes shear deformation with the relative movement of the tool body 2 and the handle 3 in the front-back and vertical directions, and also with the relative movement in the horizontal direction.

[0063] Furthermore, in this embodiment, by setting the elastic deformation characteristics of the aforementioned elastic member 55, the tool body 2 and handle 3 are allowed to rotate relative to each other with the front elastic member 55F of the front guide portion 5F as the fulcrum, thus appropriately coping with vibrations in the relative rotation direction. The front guide portion 5F is located further away from the grip portion 33 than the rear guide portion 5R. In particular, in this embodiment, the first ball retaining portion 51 (first recess 52) and the second ball retaining portion 53 (second recess 54) of the front guide portion 5F are respectively arranged at the foremost position in the overlapping portion of the motor housing portion 23 and the cover portion 31. Therefore, the transmission of vibrations in the relative rotation direction between the tool body 2 and the handle 3 to the grip portion 33 can be effectively reduced.

[0064] Furthermore, in this embodiment, the tool body 2 and the handle 3 are subjected to force by two force-applying components 41. Therefore, compared to the case where only one force-applying component 41 is provided, the relative movement of the tool body 2 and the handle 3 can be stabilized. In particular, the two force-applying components 41 are symmetrical about the rotation axis A2 of the motor shaft 711 and are arranged in different positions in the vertical and horizontal directions. Therefore, it is possible to suppress the handle 3 from unnecessarily tilting in the vertical or horizontal directions when it moves relative to the tool body 2 in the forward and backward direction.

[0065] The following shows the correspondence between the structures (features) of the above embodiments and the structures (features) of this application. However, the structures (features) of the embodiments are merely examples and do not limit the structures (features) of this application or the present invention.

[0066] Hammer drill 1 is an example of an "impact tool". Drive shaft A1 is an example of a "drive shaft". Top tool 91 is an example of a "top tool". Tool body 2 is an example of a "tool body". Motor 71 is an example of a "motor". Handle 3 is an example of a "handle". Cover 31 is an example of a "cover". Holding part 33 is an example of a "holding part". Force application part 41 is an example of a "force application part". Elastic part 55 is an example of an "elastic part". Front elastic part 55F is an example of a "front elastic part". Rear elastic part 55R is an example of a "rear elastic part". Motor shaft 711 is an example of a "motor output shaft".

[0067] <Variation Example> Furthermore, the above embodiments are merely examples, and the impact tool involved in this application is not limited to the example hammer drill 1. For example, non-limiting modifications as exemplified below can be added. In addition, at least one of these modifications can be used in combination with at least one of the structures (features) described in the hammer drill 1 and the technical solution.

[0068] In the above embodiments, a hammer drill 1 is exemplified as an impact tool, but the features of this application can also be applied to other power tools capable of performing impact actions (e.g., an electric hammer that can only perform impact actions without rotation). Furthermore, the hammer drill 1 may only have two operating modes: an impact mode and a rotation mode. Depending on the impact tool to which the features of this application are applied, the structure of the tool body 2 and handle 3, as well as the structure and configuration of the motor 71 and drive mechanism 75, can be appropriately modified.

[0069] For example, the tool body 2 can also be formed by connecting the drive mechanism housing 21 and the motor housing 23 in an L-shape when viewed from the side. Furthermore, the motor 71 can be configured such that the rotation axis A2 of the motor shaft 711 intersects the drive axis A1. In this case, the shape of the handle 3 can also be suitably modified. For example, the handle 3 can also include: a first cover portion covering a portion of the drive mechanism housing 21; a second cover portion covering a portion of the motor housing 23; and a grip portion, the two ends of which are connected to the first cover portion and the second cover portion. Additionally, in the above embodiment, the handle 3 is formed by two split bodies (left side component 3L and right side component 3R) connected to each other in the left-right direction. However, the handle 3 can also be formed, for example, by connecting split bodies that are divided in the front-back direction. Alternatively, the handle 3 can also be formed by connecting multiple components that are divided in other directions together.

[0070] Alternatively, motor 71 may be a DC motor (e.g., a brushless DC motor). In this case, for example, a battery mounting section for a removable rechargeable battery (also referred to as a battery pack) may be provided on the tool body 2 or the handle 3.

[0071] The connection structure between the tool body 2 and the handle 3 can be appropriately modified. Below are examples of modifications to the connection structure between the tool body 2 and the handle 3.

[0072] For example, the force-applying component that applies force to the tool body 2 and handle 3 in a direction that moves away from each other in the front-back direction is not limited to the force-applying component 41. For example, a spring of a different type than a compression coil spring (e.g., a tension coil spring, leaf spring, torsion spring, etc.) can also be used. Alternatively, an elastic component other than a spring, such as rubber or synthetic resin, can also be used. Furthermore, the number and position of the force-applying components 41 are not limited to the number and position exemplified in the above embodiments. For example, only one force-applying component 41 may be provided on plane P2. Three or more force-applying components 41 may also be provided. In addition, the structure of the first spring receiving portion 25 and the second spring receiving portion 35 that receive the ends of the force-applying components 41 can be appropriately changed according to the type and position of the force-applying components used.

[0073] Furthermore, the relative movement of the guide tool body 2 and the handle 3 in the front-back direction is not limited to the guide part 5 (first ball retainer 51, second ball retainer 53, elastic member 55).

[0074] For example, the structure (type, shape, etc.) of the elastic member 55 can be appropriately modified. For example, the elastic member 55 may not be made of rubber, but of a synthetic resin capable of elastic deformation (shear deformation, compression deformation). In addition, the elastic member 55 may also be an elastic member with a shape other than a ball (ball), such as a cylindrical (pin), elliptical cylinder, prism, or cylindrical shape. Depending on the modification of the elastic member 55, the structure of the first recess 52 and the second recess 54 can also be appropriately modified. For example, the first recess 52 and the second recess 54 may not be bottomed recesses, but rather openings (through holes) penetrating the wall of the motor housing 23. The elastic member with a shape other than a ball (ball) may also slide relative to the first ball holding part 51 and the second ball holding part 53 and undergo shear deformation as the tool body 2 and the handle 3 move relative to each other.

[0075] The elastic deformation characteristics (ease of elastic deformation) of the front elastic member 55F of the front guide portion 5F and the rear elastic member 55R of the rear guide portion 5R can vary depending on the material or shape. For example, the front elastic member 55F and the rear elastic member 55R can be different types of elastic members with the same shape. Alternatively, the front elastic member 55F and the rear elastic member 55R can be the same type of elastic member with different shapes, and the ease of elastic deformation varies depending on the shape. Furthermore, the elastic deformation characteristics of the front elastic member 55F can be the same as those of the rear elastic member 55R.

[0076] The configuration of the guide portion 5 is not limited to the examples described above. For example, in the above embodiment, the two guide portions 5 provided on the left and right sides of the hammer drill 1 are located on a straight line extending in the front-back direction when viewed from the side (and at the same position in the vertical direction), but they can also be arranged at different positions in the vertical direction. In addition, the two guide portions 5 can also be arranged on a straight line extending in the front-back direction at a position above or below the rotation axis A2 of the motor shaft 711 when viewed from the side. Furthermore, the positions of the two guide portions 5 can be appropriately changed in the area where the tool body 2 (motor housing 23) and the handle 3 (cover 31) overlap, but it is preferable that they are as far apart as possible from each other in the front-back direction.

[0077] The hammer drill 1 may have at least one guide portion 5, and the number of guide portions 5 is not limited to the example above (4). For example, the hammer drill 1 may have only a pair of left and right guide portions 5 (e.g., only a pair of front guide portions 5F). Alternatively, the hammer drill 1 may have only two guide portions 5 that are separately arranged in the front-back direction (e.g., only two guide portions 5 on the left side).

[0078] Furthermore, in view of the purpose of this application, the following methods are constructed. At least one of the following methods can be used in combination with at least one of the features described in the above-described embodiments, examples, modifications, and technical solutions. [Method 1] The vertical direction of the impact tool is defined by a direction orthogonal to the front-back direction and corresponding to the extension direction of the gripping part. The direction orthogonal to the front-back direction and the up-down direction defines the left-right direction of the impact tool. The at least one elastic member is disposed in the left-right direction between the side of the tool body and the cover of the handle. [Method 2] The tool body has at least one first recess extending along the front-rear direction. The cover portion of the handle has at least one second recess extending along the front-rear direction. The at least one elastic member is held in a state of partial contact with the surface of each of the at least one first recess and the at least one second recess. The first recessed portion 52 and the second recessed portion 54 are examples of the “first recessed part” and the “second recessed part” respectively. [Method 3] The at least one elastic member is configured such that, as the tool body and the handle move closer to each other in the front-rear direction beyond the predetermined range, they are pressed by the front end of the first recess and the rear end of the second recess, causing shear deformation. Furthermore, as the tool body and the handle move away from each other beyond the specified range, they are pressed by the rear end of the first recess and the front end of the second recess, resulting in shear deformation. [Method 4] The specified range is the range in which the handle moves relative to the tool body between the first position and the second position. The first position is the position where the at least one elastic member abuts against the rear end of the first recess and the front end of the second recess, respectively. The second position is the position where the at least one elastic member abuts against the front end of the first recess and the rear end of the second recess, respectively. [Method 5] In the front-back direction, the at least one elastic member is shorter than each of the first recess and the second recess. [Method 6] The vertical direction of the impact tool is defined by a direction orthogonal to the front-back direction and corresponding to the extension direction of the gripping part. The direction orthogonal to the front-back direction and the up-down direction defines the left-right direction of the impact tool. The at least one elastic component is capable of compressive deformation along the left-right direction. [Method 7] The at least one elastic component is made of rubber. [Method 8] The at least one force-applying component is at least one spring. [Method 9] The motor has an output shaft capable of rotating about an axis parallel to the drive axis. The cover is configured to be at least partially formed in a cylindrical shape to cover a portion of the tool body. One end of the gripping part is connected to the cover part, and the other end of the gripping part is a free end.

Claims

1. An impact tool, configured to drive a tip tool in a linear shape along a predetermined front-to-back direction via a drive axis, characterized in that, It has a tool body, a motor, a handle, at least one force-applying component, and at least one elastic component, wherein, The tool body extends along the drive axis; The motor is housed within the tool body; The handle is connected to the tool body in a manner that allows it to move at least along the front-rear direction. The handle includes a cover and a grip, wherein the cover covers a portion of the tool body; the grip is connected to the cover and extends in a direction intersecting the drive axis. The at least one force-applying component is located between the tool body and the handle, and applies force to the tool body and the handle in a direction that moves them away from each other in the front-back direction; The at least one elastic member is located between the tool body and the cover portion of the handle, and is movable relative to the tool body and the handle, and can undergo shear deformation as the tool body and the handle move relative to each other. The at least one elastic member is configured such that: during the movement of the handle relative to the tool body within a predetermined range along the forward-backward direction, the at least one elastic member does not substantially undergo shear deformation while moving relative to the tool body and the handle along the forward-backward direction; as the handle moves relative to the tool body beyond the predetermined range, the at least one elastic member undergoes shear deformation.

2. The impact tool according to claim 1, characterized in that, The at least one elastic member can undergo shear deformation as the tool body and the handle move relative to each other in the vertical direction, wherein the vertical direction is orthogonal to the front-back direction and corresponds to the extension direction of the grip.

3. The impact tool according to claim 1, characterized in that, The at least one elastic member includes at least one front elastic member and at least one rear elastic member, wherein the at least one rear elastic member is configured in the front-rear direction at a position closer to the gripping portion than the at least one front elastic member.

4. The impact tool according to claim 3, characterized in that, The elastic deformation characteristics of the at least one front elastic component and the elastic deformation characteristics of the at least one rear elastic component are different from each other.

5. The impact tool according to any one of claims 1 to 4, characterized in that, The at least one elastic component is formed in a spherical shape.

6. The impact tool according to claim 5, characterized in that, The at least one elastic component is capable of rolling relative to the tool body and the handle in the front-back direction.

7. The impact tool according to any one of claims 1 to 4, characterized in that, The at least one elastic member includes two elastic members, which are symmetrically arranged with respect to a plane including the drive axis and extending along the extension direction of the gripping portion.

8. The impact tool according to claim 4, characterized in that, The at least one front elastic member is configured to be less prone to elastic deformation than the at least one rear elastic member.

9. The impact tool according to any one of claims 1 to 4, characterized in that, The at least one force-applying component includes two force-applying components, which are symmetrically arranged with respect to the axis in a plane including the axis of the output shaft of the motor.

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