Impact tool

Abstract

An impact tool is provided. A movable support body at least partially supports a final output shaft and a drive mechanism, and is integrally movable in an axial direction of a drive axis with respect to a housing. A force applying member applies a force to a front side of the movable support body in the axial direction. A first guide shaft is configured to extend in the axial direction to slidably guide the movable support body to move in the axial direction. At least one intermediate shaft is configured to rotate in conjunction with rotation of a motor shaft to transmit power of the motor to the drive mechanism. At least one bearing supports an end portion of the front side in the axial direction of the first intermediate shaft. A single metal support body is configured not to move with respect to the housing and to support the at least one bearing. In addition, the single metal support body has a first hole in which the first guide shaft is partially inserted. Accordingly, high power and low vibration can be simultaneously achieved.

Description

Technical Field

[0001] The present invention relates to an impact tool configured as a linearly driven tip tool. Background Technology

[0002] A hammer drill is configured to perform hammering and drilling actions. The hammering action refers to the linear motion of a tool mounted on a tool holder along a drive axis, while the drilling action refers to the rotational motion of the tool mounted on the tool holder about the drive axis. Generally, for the hammering action, a motion conversion mechanism converts the rotational motion of the intermediate axis into linear motion; for the drilling action, a rotational transmission mechanism transmits rotation through the intermediate axis to the tool holder. During the hammering action, the hammer drill experiences a reaction force from the workpiece relative to the impact force of the tool. This reaction force primarily generates vibration in the direction extending along the drive axis (hereinafter referred to as the axial direction). This vibration is transmitted to the hammer drill housing and even the user.

[0003] Japanese Patent Publication No. 6325360 discloses a structure for absorbing such vibrations. Specifically, a retaining member holding the drive mechanism for performing the hammering action is configured to slide relative to the housing along a guide shaft. The retaining member is forceped forward by a force-applying member (i.e., in the direction of the impact force applied to the workpiece). When the tip tool receives a reaction force during the hammering action, the drive mechanism and the retaining member, along with the tip tool, move rearward relative to the housing by this reaction force. At this time, the force-applying member undergoes elastic deformation, buffering a portion of the reaction force. Through this buffering effect, the vibration transmitted to the housing due to the reaction force is reduced.

[0004] Not limited to Japanese Patent Publication No. 6325360, generally speaking, in hammer drills, resin components are used extensively for the purpose of weight reduction. For example, the housing defining the outer contour of the hammer drill is usually made of resin. In addition, components used to support the bearings supporting the intermediate shaft are also usually made of resin. Summary of the Invention

[0005] The hammer drill described in Japanese Patent Publication No. 6325360 has room for improvement. For example, when the hammer drill is made more powerful, the reaction force increases, and the resulting vibration also increases. Therefore, if the periphery of the bearing supporting the intermediate shaft is made of resin, it may not be possible to obtain sufficient strength to ensure the required positional accuracy of the intermediate shaft. In addition, when the hammer drill is made more powerful, the heat generated due to the sliding between the retaining member of the drive mechanism and the guide shaft also increases. Therefore, if the component supporting the bearing for supporting the intermediate shaft is made of resin, the resin may no longer be able to achieve the required positional accuracy of the intermediate shaft due to thermal expansion caused by the increased heat. Furthermore, when the guide shaft is supported by a resin component, the resin's thermal expansion due to the increased heat impairs the sliding properties between the retaining member and the guide shaft, which may result in compromised vibration resistance. This problem is not limited to hammer drills; it exists in various impact tools where the retaining member is configured to slide relative to the housing along the guide shaft, wherein the retaining member holds the drive mechanism for performing the hammering action.

[0006] In view of this situation, the present invention aims to provide an impact tool that can simultaneously achieve high power and low vibration.

[0007] This specification discloses an impact tool. The impact tool may have a final output shaft, a motor, a drive mechanism, a housing, a movable support, a force-applying component, a first guide shaft, at least one intermediate shaft, at least one bearing, and a single metal support.

[0008] The final output shaft can be configured to detachably hold the tip tool. Additionally, the final output shaft can define the drive axis of the tip tool. The motor can have a motor shaft. The drive mechanism can be configured to perform a hammering action by driving the tip tool linearly along the drive axis using the power of the motor. The housing can house the motor and the drive mechanism. A movable support can at least partially support the final output shaft and the drive mechanism. Furthermore, the movable support can be configured to move integrally with respect to the housing along the axial direction of the drive axis. When the side with the final output shaft positioned in the axial direction is defined as the front side, and the side with the motor positioned is defined as the rear side, the force-applying member can apply force to the movable support towards the front side in the axial direction. The first guide shaft can be configured to extend along the axial direction to slide and guide the movable support to move along the axial direction. At least one intermediate shaft can extend along the axial direction. Furthermore, at least one intermediate shaft can be configured to rotate along with the rotation of the motor shaft, transmitting the power of the motor to the drive mechanism. At least one bearing can support the front end of the first intermediate shaft in the axial direction. A single metal support body can be configured to remain stationary relative to the housing and support at least one bearing. Additionally, the single metal support body may have a first hole in which a first guide shaft is partially inserted.

[0009] The first guide shaft can be configured to move integrally with the movable support along the axial direction. In this case, the first guide shaft can be inserted into the first hole of the metal support in a manner that allows it to slide along the axial direction as the movable support moves. Alternatively, the first guide shaft can be fixedly inserted into the first hole of the metal support. In this case, the first guide shaft held by the metal support can be slidably inserted into a hole formed in the movable support.

[0010] According to the aforementioned impact tool, at least one bearing supporting the front end of at least one intermediate shaft is supported by a metal support body. Therefore, compared to the case where at least one bearing is supported by a resin support body, greater support strength can be obtained. Thus, even if the vibration caused by the reaction force of the impact force increases with the increased power of the impact tool, the required positional accuracy for at least one intermediate shaft can be ensured. Furthermore, according to this impact tool, the first guide shaft is partially inserted into the first hole of the metal support body. Therefore, even if the heat generated when the first guide shaft slides along the axial direction to guide the movable support body in a sliding manner increases with the increased power of the impact tool, the thermal expansion of the support body can be suppressed compared to the case where the first guide shaft is inserted into a resin support body. Therefore, the positional accuracy of the first guide shaft partially inserted into the first hole of the metal support body can be ensured. As a result, good sliding performance of the first guide shaft can be ensured, thereby achieving good vibration damping. Thus, the impact tool of this embodiment can simultaneously achieve high power and low vibration. Furthermore, by using a single metal support body to support at least one bearing and insert the first guide shaft, the device structure can be simplified and the manufacturing time can be reduced. Attached Figure Description

[0011] Figure 1 This is a cross-sectional view of a hammer drill according to an embodiment of the present invention.

[0012] Figure 2 yes Figure 1 Sectional view II-II.

[0013] Figure 3 yes Figure 2 Sectional view III-III.

[0014] Figure 4 yes Figure 2 Sectional view IV-IV.

[0015] Figure 5 yes Figure 2 VV sectional view.

[0016] Figure 6 yes Figure 2 Sectional view VI-VI.

[0017] Figure 7 yes Figure 2 Sectional view VII-VII, with the movable support located at the foremost position.

[0018] Figure 8 yes Figure 2 Sectional view VII-VII, with the movable support located at the rearmost position.

[0019] Figure 9 yes Figure 2 The IX-IX sectional view shows the movable support located at the foremost position.

[0020] Figure 10 yes Figure 2 The IX-IX sectional view shows the movable support located at the foremost position.

[0021] Figure 11 This is a three-dimensional view of the first support.

[0022] Figure 12 It is a three-dimensional view of a movable support.

[0023] Figure 13 This is a three-dimensional view of the second support.

[0024] Figure 14 This is a three-dimensional view of the second support.

[0025] Explanation of reference numerals in the attached figures

[0026] 2: Motor; 5: Drive mechanism; 6: Impact mechanism; 7: Rotary transmission mechanism; 10: Main housing; 11: Rear housing; 13: Front housing; 15: First support body; 16: Second support body; 17: Handle; 18: Movable support body; 20: Main body; 25: Motor shaft; 26: Airflow channel; 27: Cooling fan; 28: Air inlet; 29: Exhaust port; 31: Spindle; 32: Tool holder; 33: Cylinder; 41: First intermediate shaft; 42: Second intermediate shaft; 61: Motion conversion component; 63: Clamping component; 64: First transmission component; 65: Piston; 67: Impact hammer; 6 8: Bolt; 72: Second transmission component; 73: Torque limiter; 74: Drive side component; 75: Driven side component; 77: Force spring; 78: Drive gear; 79: Driven gear; 91: Top tool; 101: Hammer drill; 131: Cylindrical part; 132: Auxiliary handle; 133: Second positioning part; 135: Mounting surface; 150: Base; 151: O-ring; 152: Groove; 153: Through hole; 154, 155: Bearing support part; 156: Shaft support part; 158: Elastic component retaining part; 159: Hole; 161: Screw; 162: Through hole; 163: First positioning part; 16 4. 165: Bearing support; 166: Hole; 167: Sleeve; 168: Mounting surface; 171: Trigger; 172: Switch; 179: Power cable; 180: Movable unit; 181, 182: Cylindrical part; 183, 184: Hole; 185: Spindle support; 186: Sleeve; 187: Rotating body support; 188: Protrusion; 189: Abutment part; 191: First guide shaft; 192: Second guide shaft; 193: Force spring; 194: Elastic component; 195: Shim; 251, 252: Bearing; 255: Pinion; 316, 317: Bearing; 330: Tool Head insertion hole; 411, 412: bearings; 414: first driven gear; 416: splined part; 421, 422: bearings; 423: gear assembly; 424: second driven gear; 425: splined part; 611: rotating body; 612: splined part; 614: bearing; 616: swinging part; 617: arm; 631: splined part; 641: first splined part; 642: second splined part; 721: first splined part; 722: second splined part; 743: splined part; 800: mode switching dial; A1: drive axis; A2, A3, A4: rotation axis; P1: imaginary plane. Detailed Implementation

[0027] In one or more embodiments, the housing may be made of resin. A metal support may be fixed to the housing. According to this embodiment, it is possible to simultaneously achieve high power and low vibration while making the impact tool lightweight.

[0028] In one or more embodiments, the metal support body may have a first positioning portion on its front side, which is configured to surround the final output shaft in the circumferential direction. The housing may have a second positioning portion, which is configured to surround the final output shaft in the circumferential direction. The shapes of the first and second positioning portions may be formed to fit together in the axial direction. According to this embodiment, when assembling the impact tool, the first and second positioning portions can be aligned and fitted together, thereby easily positioning the metal support body relative to the housing in a direction orthogonal to the axial direction.

[0029] In one or more embodiments, the metal support may have a mounting surface on its front side, which unfolds on a single plane at a position radially outward from the first positioning part. The mounting surface may abut against the housing in the axial direction. According to this embodiment, when assembling the impact tool, the mounting surface abutting against the housing in the axial direction allows for easy positioning of the metal support relative to the housing in the axial direction.

[0030] In one or more embodiments, the first guide shaft may be configured to be at least partially located forward of the movable support. The impact tool may also have a second guide shaft, which is coaxially configured with the first guide shaft in a manner that is at least partially located rearward of the movable support. According to this embodiment, compared to a single guide shaft extending from the position of the first guide shaft to the position of the second guide shaft, the overall extension distance of the guide shaft can be shortened. Therefore, the impact tool can be made lighter. Furthermore, since the guide shafts are located on opposite sides of the movable support in the axial direction, the guiding performance is not reduced along with the weight reduction.

[0031] In one or more embodiments, the first guide shaft can extend forward from the movable support. Furthermore, the first guide shaft can be configured to move integrally with the movable support along the axial direction. According to this embodiment, good sliding performance with respect to the first guide shaft can be ensured.

[0032] In one or more embodiments, the metal support body may have a first sleeve made of an ferrous metal within the first hole. The first guide shaft may be configured to slide on the inner circumferential surface of the first sleeve as the movable support body moves along its axial direction. Besides the first sleeve, the metal support body may be made of an aluminum-based metal. Ferrous metals include iron and alloys with iron as the main component. Aluminum-based metals include aluminum and alloys with aluminum as the main component. According to this embodiment, sufficient strength can be ensured for relative sliding with the first guide shaft, and the overall weight reduction of the metal support body can be achieved.

[0033] In one or more embodiments, the movable support body may have a second hole and a second sleeve, with a second guide shaft partially inserted into the second hole; the second sleeve is disposed within the second hole. The second guide shaft may be configured to be immovable relative to the housing. The inner circumferential surface of the second sleeve may be configured to slide on the second guide shaft as the movable support body moves along the axial direction. A force-applying member is disposed around the second guide shaft at a position further rearward than the movable support body in the axial direction, configured to apply force integrally to the movable support body including the second sleeve towards the front. According to this embodiment, only the second sleeve in the movable support body is in a sliding relationship with the second guide shaft; therefore, if the material of the second sleeve is selected to be a material with sufficient strength, smooth sliding can be ensured. In addition, since the second sleeve is forceped towards the front by the force-applying member, when the movable support body moves towards the front, it will not leave the second sleeve and disengage from the second hole.

[0034] In one or more embodiments, the drive mechanism may also be configured to perform a drilling action by rotating the tip tool around a drive axis via the power of a motor. At least one intermediate shaft may have a first intermediate shaft and a second intermediate shaft, wherein the first intermediate shaft is configured to transmit power for the hammering action to the drive mechanism; and the second intermediate shaft is configured to transmit power for the drilling action to the drive mechanism. At least one bearing may have a first bearing supporting the first intermediate shaft and a second bearing supporting the second intermediate shaft. The first intermediate shaft may be configured to transmit power for the hammering action but not for the drilling action, and the second intermediate shaft may be configured to transmit power for the drilling action but not for the hammering action. According to this embodiment, compared to the case where a single common intermediate shaft is used for both the hammering and drilling actions, the first and second intermediate shafts can be shortened (shortened). Accordingly, the overall size of the impact tool in the axial direction can be shortened. Furthermore, the first and second intermediate shafts are dedicated to power transmission for the hammering action and power transmission for the drilling action, respectively. Therefore, it is possible to optimize the power transmission from the first intermediate shaft to the drive mechanism, from the second intermediate shaft to the drive mechanism, and ultimately to the final output shaft.

[0035] In one or more embodiments, the first bearing and the second bearing can be respectively arranged at offset positions in the axial direction. According to this embodiment, the arrangement of the first bearing and the second bearing can be set without being restricted by the metal support body. Therefore, the arrangement of the first bearing and the second bearing can be set in a manner that does not impair the shortening effect of the first intermediate shaft and the second intermediate shaft. In other words, it is possible to suppress the lengthening of the impact tool due to the introduction of the metal support body.

[0036] Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

[0037] In this embodiment, the hammer drill 101 is exemplified as an impact tool. The hammer drill 101 is a handheld power tool used for chiseling, drilling and other processing operations. It can perform actions such as driving the tip tool 91 in a straight line along a predetermined drive axis A1 (hereinafter referred to as hammering action) and driving the tip tool 91 to rotate around the drive axis A1 (hereinafter referred to as drilling action).

[0038] First, refer to Figure 1 The general structure of the hammer drill 101 will be briefly described. For example... Figure 1 As shown, the outer contour of the hammer drill 101 is mainly formed by the main body housing 10 and the handle 17 connected to the main body housing 10.

[0039] The main housing 10 is a hollow body, also referred to as the tool body or outer contour housing, which houses the spindle 31, motor 2, drive mechanism 5, etc. The spindle 31 is an elongated cylindrical component with a tool holder 32 at one end in the axial direction, which detachably holds the tip tool 91. The long axis of the spindle 31 defines the drive axis A1 of the tip tool 91. The main housing 10 extends along the drive axis A1. The tool holder 32 is disposed within one end of the main housing 10 in the extending direction of the drive axis A1 (hereinafter simply referred to as the axial direction).

[0040] The handle 17 is an elongated, hollow body for the user to grip. One end of the handle 17 in the axial direction is connected to the other end of the main body housing 10 in the axial direction (the end opposite to the end where the tool holder 32 is disposed). The handle 17 extends from the other end of the main body housing 10 in a direction intersecting (more specifically, approximately orthogonal) the drive axis A1. Furthermore, in this embodiment, the main body housing 10 and the handle 17 are integrated by connecting multiple components together with screws or the like. A power cable 179 capable of connecting to an external AC power source extends from the protruding end of the handle 17. The handle 17 has a trigger 171 for the user to press (pull) and a switch 172 that becomes active in response to the pressing of the trigger 171.

[0041] In the hammer drill 101, when the switch 172 is in the ON state, the motor 2 is energized, which drives the drive mechanism 5 to perform hammering and / or drilling actions.

[0042] The detailed structure of the hammer drill 101 will now be described. For convenience, in the following description, the extension direction of the drive axis A1 (the long axis direction of the main body housing 10) is defined as the front-rear direction of the hammer drill 101. In the front-rear direction, the side where the tool holder 32 is disposed is defined as the front side of the hammer drill 101, and the opposite side (the side where the motor 2 is disposed) is defined as the rear side. Furthermore, the direction orthogonal to the drive axis A1 and corresponding to the axial direction of the handle 17 is defined as the vertical direction of the hammer drill 101. In the vertical direction, the side where the handle 17 is connected to the main body housing 10 is defined as the upper side, and the protruding end side of the handle 17 is defined as the lower side. Additionally, the direction orthogonal to both the front-rear and vertical directions is defined as the left-right direction of the hammer drill 101. In the left-right direction, the right side when viewing the front from the rear is defined as the right side of the hammer drill 101, and the opposite side is defined as the left side of the hammer drill 101.

[0043] First, the structure of the main shell 10 will be described. For example... Figure 1 As shown, the main housing 10 has a cylindrical front end. This cylindrical portion is referred to as the cylindrical portion 131. The portion of the main housing 10 other than the cylindrical portion 131 is formed into a generally rectangular box shape. An auxiliary handle 132 is detachably mounted on the cylindrical portion 131.

[0044] The internal space of the main housing 10 is divided into two regions by a first support 15 disposed inside the main housing 10. The first support 15 is configured to intersect the drive axis A1 and is embedded in the inner circumference of the main housing 10, and is held in place by the main housing 10 being fixed in a fixed position (not movable relative to the main housing 10). The rear region of the first support 15 is mainly used to house the motor 2. The front region of the first support 15 is mainly used to house the main shaft 31 and the drive mechanism 5. Hereinafter, the part of the main housing 10 corresponding to the housing area of ​​the motor 2 will be referred to as the rear housing 11, and the part corresponding to the housing area of ​​the main shaft 31 and the drive mechanism 5 (including the cylindrical part 131) will be referred to as the front housing 13.

[0045] Both the rear housing 11 and the front housing 13 are made of resin (plastic). This allows for a lighter hammer drill 101. However, at least a portion of the rear housing 11 and the front housing 13 can also be formed of any material (e.g., metal). The rear housing 11 and the front housing 13 are each a single cylindrical component.

[0046] The first support body 15 is a component that supports bearings for various shafts, and its details will be described later. To ensure the positional accuracy of these bearings, the first support body 15 is formed of metal. In this embodiment, the first support body 15 is formed of an aluminum-based metal. This allows for a lighter weight for the hammer drill 101. Figure 1The first support 15 is embedded in the rear end of the front housing 13 such that its outer peripheral surface contacts the inner peripheral surface of the front housing 13.

[0047] like Figure 1 As shown, an annular groove 152 is formed on the outer peripheral surface of the first support 15 that contacts the inner peripheral surface of the main housing 10. A rubber O-ring 151 is installed in the groove 152. The O-ring 151 functions as a sealing member to close the gap between the main housing 10 and the first support 15, preventing the lubricant used in the front housing 13 from leaking into the rear housing 11.

[0048] The internal structure of the main housing 10 will now be described. First, the motor 2 will be explained. In this embodiment, the motor 2 is an AC motor driven by power supplied from an external AC power source. Figure 1 As shown, the motor 2 is fixed to the rear housing 11. The motor 2 has: a main body 20, which includes a stator and a rotor; and a motor shaft 25, which is configured to rotate integrally with the rotor. In this embodiment, the rotation axis A2 of the motor shaft 25 extends parallel to the drive axis A1 at a position lower than the drive axis A1.

[0049] The motor shaft 25 is supported on the main housing 10 by two bearings 251 and 252 in a manner that allows it to rotate about the rotation axis A2. The front bearing 251 is held on the rear surface of the first support 15, and the rear bearing 252 is held in the rear housing 11.

[0050] A cooling fan 27 for cooling the motor 2 is fixed in the portion of the motor shaft 25 between the main body 20 and the front bearing 251. The cooling fan 27 is a centrifugal fan that exhausts air drawn in along the axial direction radially outward. As the cooling fan 27 rotates along with the motor shaft 25, it generates airflow passing through the interior of the hammer drill 101. This airflow enters the interior of the hammer drill 101 from the outside via the air inlet 28, flows axially through the motor 2 (more specifically, between the rotor and stator), flows radially outward through the cooling fan 27, and is exhausted to the outside from the exhaust port 29. Figure 1 In the image, arrow 26 is used to indicate the path of the airflow generated in this way.

[0051] exist Figure 1The diagram shows an example where the air inlet 28 is formed on the side of the handle 17 and the exhaust outlet 29 is formed on the bottom surface of the rear housing 11. However, the air inlet 28 and exhaust outlet 29 can be formed in any position. For example, in addition to the side of the handle 17, the air inlet 28 can be formed on the upper surface of the handle 17, or instead of the side of the handle 17, the air inlet 28 can be formed on the upper surface of the handle 17. Similarly, in addition to the bottom surface of the rear housing 11, the exhaust outlet 29 can be formed on one or both sides or the upper surface of the rear housing 11, or instead of the bottom surface of the rear housing 11, the exhaust outlet 29 can be formed on one or both sides or the upper surface of the rear housing 11. The airflow generated in this way cools the motor 2.

[0052] The first support body 15 is arranged adjacent to the cooling fan 27 in the front-rear direction, and the space behind the first support body 15 is in communication with the space where the cooling fan 27 is arranged. Furthermore, in this embodiment, the first support body 15 is made of metal. Therefore, the airflow passing through the channel 26 can also cool the first support body 15. In other words, the first support body 15 can be configured to dissipate heat generated and transferred to the first support body 15 at a position further forward than the first support body 15. Details of this point will be described later.

[0053] The front end of the motor shaft 25 passes through the through hole 153 of the first support body 15 and protrudes into the front housing 13. A pinion 255 is fixed to the portion protruding into the front housing 13.

[0054] Next, the power transmission path from the motor shaft 25 to the drive mechanism 5 will be explained. For example... Figure 2 and Figure 3 As shown, in this embodiment, the hammer drill 101 has two intermediate shafts (a first intermediate shaft 41 and a second intermediate shaft 42). Furthermore, the drive mechanism 5 is configured to perform a hammering action using power transmitted from the first intermediate shaft 41, and a drilling action using power transmitted from the second intermediate shaft 42. That is, the first intermediate shaft 41 is a dedicated shaft for power transmission of the hammering action, and the second intermediate shaft 42 is a dedicated shaft for power transmission of the drilling action.

[0055] Both the first intermediate shaft 41 and the second intermediate shaft 42 extend parallel to the drive axis A1 and the rotation axis A2 within the front housing 13. Figure 3 As shown, the first intermediate shaft 41 is supported on the main housing 10 by two bearings 411 and 412 in a manner that allows it to rotate about the rotation axis A3. Similarly, the second intermediate shaft 42 is supported on the main housing 10 by two bearings 421 and 422 in a manner that allows it to rotate about the rotation axis A4.

[0056] The bearing 411, which supports the first intermediate shaft 41 at the front, and the bearing 421, which supports the second intermediate shaft 42 at the front, are supported by the second support body 16. More specifically, the bearing 411 is supported by a generally cylindrical bearing support portion 164 in the second support body 16, and the bearing 421 is supported by a generally cylindrical bearing support portion 165 (see reference). Figure 3 , Figure 13 and Figure 14 The bearing 412, which supports the first intermediate shaft 41 at the rear, and the bearing 422, which supports the second intermediate shaft 42 at the rear, are supported by the first support body 15. More specifically, the bearing 412 is supported by a generally cylindrical bearing support portion 154 in the first support body 15, and the bearing 422 is supported by a generally cylindrical bearing support portion 155 (see reference). Figure 3 and Figure 11 ).

[0057] like Figure 3 As shown, the bearing 411 supporting the first intermediate shaft 41 on the front side and the bearing 421 supporting the second intermediate shaft 42 on the front side are respectively arranged in a staggered position in the front-rear direction. This is because the bearings 411 and 421 are arranged in a position that maximizes the shortening of the first intermediate shaft 41 and the second intermediate shaft 42. That is, although the bearings 411 and 421 are supported by a single component, namely the second support body 16, the position of the bearings 411 and 421 in the front-rear direction is not constrained by the second support body 16. Therefore, it is possible to prevent the hammer drill 101 from becoming elongated due to supporting the bearings 411 and 421 by a single component.

[0058] like Figure 1 and Figure 3 As shown, the second support 16 is fixed to the inside of the front housing 13. More specifically, as... Figure 13 and Figure 14 As shown, the second support body 16 has a first positioning portion 163, a mounting surface 168, and two through holes 162. The first positioning portion 163 is a cylindrical part protruding forward. Figure 7 and Figure 8 As shown, the first positioning part 163 is arranged in such a way that it surrounds the main shaft 31 in the circumferential direction (in other words, the main shaft 31 passes through the first positioning part 163 in the front-rear direction). Figure 13 and Figure 14 As shown, the mounting surface 168 is located radially outward from the first positioning part 163, and unfolds on a single plane orthogonal to the front-rear direction. Two through holes 162 penetrate the second support body 16 in the front-rear direction.

[0059] On the other hand, such as Figure 7 and Figure 8As shown, the front housing 13 for fixing the second support 16 has a second positioning portion 133 and a mounting surface 135. The second positioning portion 133 is a portion of the inner part of the front housing 13 that protrudes rearward and has a recess formed on the radially inner side, surrounding the main shaft 31 in the circumferential direction. The rear end face of the second positioning portion 133 is formed as a mounting surface 135 orthogonal to the front-rear direction.

[0060] like Figure 7 and Figure 8 As shown, the second support 16 is mounted to the front housing 13 such that the first positioning portion 163 fits into the recess of the second positioning portion 133 in the front-rear direction. By employing this interlocking structure based on the concave-convex shape, the second support 16 can be easily and accurately positioned relative to the front housing 13 in a direction orthogonal to the front-rear direction when assembling the hammer drill 101. In an alternative embodiment, the concave-convex relationship between the first positioning portion 163 and the second positioning portion 133 can also be reversed. That is, the first positioning portion 163 can be a recess formed on the second support 16, and the second positioning portion 133 can be a protrusion formed on the front housing 13 that fits into the recess of the second support 16.

[0061] like Figure 7 and Figure 8 As shown, with the first positioning part 163 fitted into the second positioning part 133 in the front-rear direction, the mounting surface 168 of the second support 16 abuts against the mounting surface 135 of the front housing 13 in the front-rear direction. Both mounting surfaces 168 and 135 are planes orthogonal to the front-rear direction; therefore, when assembling the hammer drill 101, the second support 16 can be easily and accurately positioned relative to the front housing 13 in the front-rear direction.

[0062] like Figure 4 As shown, the second support 16, which is thus positioned in the front housing 13, is fixed to the front housing 13 by screws 161 that are respectively inserted into the through holes 162 of the second support 16.

[0063] To ensure the positional accuracy of bearings 411 and 421, a second support body 16 with this structure is formed of metal. In this embodiment, the second support body 16 is formed of an aluminum-based metal. Accordingly, the hammer drill 101 can be made lighter.

[0064] like Figure 3 As shown, a first driven gear 414 is fixed at the rear end of the first intermediate shaft 41, adjacent to the front side of the bearing 412. The first driven gear 414 meshes with the pinion 255.

[0065] At the rear end of the second intermediate shaft 42, adjacent to the front side of the bearing 422, a gear component 423 is disposed, which has a second driven gear 424. The second driven gear 424 meshes with a pinion 255. The gear component 423 is formed in a cylindrical shape and is disposed on the outer periphery of the second intermediate shaft 42 (more specifically, the drive-side component 74 described later). A spline portion 425 is provided on the outer periphery of the cylindrical front end of the gear component 423. The spline portion 425 has a plurality of splines (external teeth) extending in the direction (front-back direction) along the axis of rotation A4. The rotation of the second driven gear 424 (gear component 423) is transmitted to the second intermediate shaft 42 via the second transmission component 72 and the torque limiter 73, details of which will be described later.

[0066] Thus, in this embodiment, two power transmission paths are provided branching off from the motor shaft 25. These paths serve as a power transmission path dedicated to the hammering action and a power transmission path dedicated to the drilling action, respectively.

[0067] The spindle 31 will be described below. Spindle 31 is the final output shaft of the hammer drill 101. (As follows...) Figure 1 As shown, the main shaft 31 is disposed within the front housing 13 along the drive axis A1 and is supported on the main housing 10 in a manner rotatable about the drive axis A1. The main shaft 31 is configured as an elongated cylindrical component with steps.

[0068] The front half of the spindle 31 forms a tool holder 32 for the detachable tip tool 91. The tip tool 91 is inserted into the tool head insertion hole 330 at the front end of the tool holder 32 with its long axis aligned with the drive axis A1, and is held in a state that allows it to move relative to the tool holder 32 along the axial direction but restricts its rotation about the axis. The rear half of the spindle 31 forms a cylinder 33 that slidably holds the piston 65 (described later). The spindle 31 is supported by a bearing 316 held in the cylindrical portion 131 and a bearing 317 held in the movable support body 18 (described later).

[0069] The drive mechanism 5 will now be described. Figure 3 , Figure 5 and Figure 6 As shown, in this embodiment, the drive mechanism 5 includes an impact mechanism 6 and a rotation transmission mechanism 7. The impact mechanism 6 is configured to perform a hammering action, converting the rotational motion of the first intermediate shaft 41 into linear motion, driving the tip tool 91 linearly along the drive axis A1. The rotation transmission mechanism 7 is configured to perform a drilling action, transmitting the rotational motion of the second intermediate shaft 42 to the spindle 31, causing the tip tool 91 to rotate around the drive axis A1. The detailed structures of the impact mechanism 6 and the rotation transmission mechanism 7 will be described below.

[0070] In this embodiment, such as Figure 3 and Figure 5 As shown, the impact mechanism 6 includes a motion conversion component 61, a piston 65, a hammer 67, and a bolt 68.

[0071] A motion conversion component 61 is disposed around the first intermediate shaft 41, configured to convert the rotational motion of the first intermediate shaft 41 into linear motion and transmit it to the piston 65. More specifically, the motion conversion component 61 includes a rotating body 611 and a swinging component 616. The rotating body 611 is supported on the main housing 10 by a bearing 614 in a manner rotatable about a rotation axis A3. The swinging component 616 is rotatably mounted on the outer periphery of the rotating body 611, configured to swing along the extension direction (front-back direction) of the rotation axis A3 as the rotating body 611 rotates. The swinging component 616 has an arm 617 extending upward from the rotating body 611.

[0072] The piston 65 is a bottomed cylindrical component, which is configured to slide along the drive axis A1 within the cylinder 33 of the main shaft 31. The piston 65 is connected to the arm 617 of the swing member 616 via a connecting pin, and reciprocates in the back-and-forth direction as the swing member 616 swings.

[0073] The hammer 67 is an impact member used to apply impact force to the tip tool 91. The hammer 67 is configured within the piston 65 in a manner that allows it to slide along the drive axis A1. The internal space of the piston 65 behind the hammer 67 is defined as an air chamber functioning as an air spring. The striker 68 is an intermediate member that transmits the kinetic energy of the hammer 67 to the tip tool 91. The striker 68 is configured within the tool holder 32, in a manner that allows it to move along the drive axis A1, on the front side of the hammer 67.

[0074] As the piston 65 moves forward and backward in tandem with the swinging member 616, the air pressure in the air chamber changes, causing the hammer 67 to slide forward and backward within the piston 65 via the action of the air spring. More specifically, when the piston 65 moves forward, the air in the air chamber is compressed, increasing the internal pressure. The hammer 67 is propelled forward at high speed by the air spring to impact the striker 68. The striker 68 transmits the kinetic energy of the hammer 67 to the tip tool 91. Accordingly, the tip tool 91 is driven linearly along the drive axis A1. On the other hand, when the piston 65 moves backward, the air in the air chamber expands, decreasing the internal pressure, and the hammer 67 is pulled backward. The tip tool 91 moves backward together with the striker 68 by being pressed against the workpiece. In this way, the hammering action is repeated by the impact mechanism 6.

[0075] In this embodiment, the rotational motion of the first intermediate shaft 41 is transmitted to the motion conversion member 61 (more specifically, the rotating body 611) via the first transmission member 64 and the clamping member 63. The clamping member 63 and the first transmission member 64 will be described in turn.

[0076] like Figure 5 As shown, the clamping member 63 is arranged coaxially with the first intermediate shaft 41 around the first intermediate shaft 41, and is a cylindrical member located between the first intermediate shaft 41 and the motion conversion member 61 (more specifically, the rotating body 611). The clamping member 63 cannot move relative to the first intermediate shaft 41 in the front-back direction, but can rotate relative to the first intermediate shaft 41 about the rotation axis A3.

[0077] More specifically, the front end of the first intermediate shaft 41 (the portion adjacent to the rear side of the front bearing 411) is configured as a maximum diameter portion with the largest outer diameter. A spline portion 416 is provided on the outer periphery of the maximum diameter portion. The spline portion 416 has a plurality of splines (external teeth) extending in the direction of the rotation axis A3 (front-rear direction). The clamping member 63 is held between the spline portion 416 and the first driven gear 414 in a manner that prevents movement in the front-rear direction, wherein the first driven gear 414 is fixed to the rear end of the first intermediate shaft 41.

[0078] Additionally, a spline portion 631 covering approximately the entire length of the clamping member 63 is provided on the outer periphery of the clamping member 63. The spline portion 631 has a plurality of splines (external teeth) extending along the rotation axis A3 in the direction (front-back direction).

[0079] On the other hand, a spline portion 612 is formed on the inner circumference of the rotating body 611. The spline portion 612 has splines (internal teeth) that engage with the spline portion 631. The clamping member 63 is always engaged with the spline of the rotating body 611 and is held by the rotating body 611. According to this structure, the rotating body 611 can move relative to the clamping member 63 and the first intermediate shaft 41 along the rotation axis A3 (front-back direction) and can rotate integrally with the clamping member 63.

[0080] The first transmission member 64 is disposed on the first intermediate shaft 41 and is configured to be able to rotate integrally with the first intermediate shaft 41 and to move relative to the first intermediate shaft 41 and the clamping member 63 in the direction of rotation axis A3 (front and back direction).

[0081] More specifically, the first transmission member 64 is a generally cylindrical member disposed around the first intermediate shaft 41, and a first spline portion 641 and a second spline portion 642 are provided on the inner periphery of the first transmission member 64.

[0082] A first spline portion 641 is provided at the rear end of the first transmission member 64. The first spline portion 641 has a plurality of splines (internal teeth) that engage with the spline portion 631 of the clamping member 63. Furthermore, as described above, the spline portion 631 of the clamping member 63 also engages with the spline portion 612 of the rotating body 611. A second spline portion 642 is provided in the front half of the first transmission member 64. The second spline portion 642 has a plurality of splines (internal teeth) that always engage with the spline portion 416 of the first intermediate shaft 41.

[0083] Through this structure, such as Figure 5 As shown, when the first spline portion 641 of the first transmission member 64, which can move in the front-back direction, is arranged in the front-back direction in a position engaging with the spline portion 631 of the clamping member 63 (hereinafter referred to as the engaging position), the first transmission member 64 can rotate integrally with the clamping member 63, that is, it can transmit power from the first intermediate shaft 41 to the clamping member 63.

[0084] On the other hand, when the first spline portion 641 of the first transmission member 64, which is capable of moving in the front-back direction, is positioned in the front-back direction at a position where the first spline portion 641 is away from (cannot engage) the spline portion 631 (hereinafter referred to as the away position) (not shown), the first transmission member 64 cannot (disconnect) transmit power from the first intermediate shaft 41 to the clamping member 63.

[0085] like Figure 6 As shown, in this embodiment, the rotary transmission mechanism 7 includes a drive gear 78 and a driven gear 79. The drive gear 78 is fixed to the front end of the second intermediate shaft 42 (the portion adjacent to the rear side of the front bearing 421). The driven gear 79 is fixed to the outer periphery of the cylinder 33 of the main shaft 31 and meshes with the drive gear 78. The drive gear 78 and the driven gear 79 constitute a gear reduction mechanism. As the drive gear 78 rotates integrally with the second intermediate shaft 42, the main shaft 31 rotates integrally with the driven gear 79. Accordingly, a drilling operation is performed, in which the top tool 91 held in the tool holder 32 is driven to rotate about the drive axis A1.

[0086] As described above, in this embodiment, the rotational motion of the second driven gear 424, which rotates along with the motor shaft 25, is transmitted to the second intermediate shaft 42 via the second transmission member 72 and the torque limiter 73. The torque limiter 73 and the second transmission member 72 will be described below.

[0087] like Figure 6As shown, the torque limiter 73 includes a drive-side component 74, a driven-side component 75, and a force-applying spring 77. The drive-side component 74 is a cylindrical component rotatably supported on the second intermediate shaft 42 via the rear half of the second intermediate shaft 42. The driven-side component 75 is a cylindrical component disposed around the second intermediate shaft 42 on the front side of the drive-side component 74. The driven-side component 75 is configured to rotate integrally with the second intermediate shaft 42 and to move relative to the second intermediate shaft 42 in the direction of the rotation axis A4 (front-rear direction). The force-applying spring 77 always applies a force to the driven-side component 75 in a direction closer to the drive-side component 74. Therefore, normally, the front end of the drive-side component 74 engages with the rear end of the driven-side component 75, enabling torque transmission from the drive-side component 74 to the driven-side component 75, and even enabling rotation of the second intermediate shaft 42.

[0088] When a load exceeding a threshold is applied to the second intermediate shaft 42 via the tool holder 32 (spindle 31) during its rotation, the driven side component 75 moves away from the driving side component 74 (forward) against the loading force of the force-applying spring 77, and the engagement between the driven side component 75 and the driving side component 74 is released. As a result, the torque transmission from the driving side component 74 to the driven side component 75 is interrupted, and the rotation of the second intermediate shaft 42 is stopped.

[0089] The drive-side component 74 includes a spline portion 743. The spline portion 743 is disposed on the outer periphery of the drive-side component 74 and has a plurality of splines (external teeth) extending along the rotation axis A4 in the direction (front-back direction).

[0090] like Figure 6 As shown, the second transmission member 72 is disposed around the second intermediate shaft 42 and is configured to be able to rotate integrally with the drive side member 74 of the torque limiter 73 and to move relative to the drive side member 74 and the gear member 423 in the direction of rotation axis A4 (front and back direction).

[0091] More specifically, the second transmission member 72 is a generally cylindrical component disposed around the drive-side member 74, and a first spline portion 721 and a second spline portion 722 are provided on the inner circumference of the second transmission member 72. The first spline portion 721 is located in the front half of the second transmission member 72. The first spline portion 721 has a plurality of splines (internal teeth) that always engage with the spline portion 743 of the drive-side member 74. The second spline portion 722 is located in the rear end of the second transmission member 72 and has an inner diameter larger than that of the first spline portion 721. The second spline portion 722 has a plurality of splines (internal teeth) that can engage with the spline portion 425 of the gear member 423.

[0092] Based on this structure, such as Figure 6As shown, when the second spline portion 722 of the second transmission member 72, which is movable in the front-rear direction, is positioned in the front-rear direction to engage with the spline portion 425 of the gear member 423 (hereinafter referred to as the engagement position), the second transmission member 72 can rotate integrally with the gear member 423. Therefore, the second intermediate shaft 42, which transmits torque via the drive-side member 74 and even the driven-side member 75 that engage with the spline of the second transmission member 72, can also rotate integrally with the gear member 423.

[0093] On the other hand, when the second spline portion 722, which can move in the front-back direction, is configured in the front-back direction at a position away from the spline portion 425 (cannot engage) (hereinafter referred to as the away position) (not shown), the second transmission member 72 cannot (disconnect) transmit power from the gear member 423 to the drive side member 74 and even the second intermediate shaft 42.

[0094] As explained above, in this embodiment, the first transmission member 64 and the clamping member 63 function as a first clutch mechanism for transmitting or disconnecting power for the hammering action, and the second transmission member 72 and the gear member 423 function as a second clutch mechanism for transmitting or disconnecting power for the drilling action. The first and second clutch mechanisms are respectively responsive to the user operation mode switching dial 800 (see reference). Figure 1 The system switches between a power transmission state and a disconnected state. More specifically, an intermediate component (not shown) configured to be linked to the mode switching dial 800 changes the position of the first transmission component 64 and / or the second transmission component 72 according to the dial position of the mode switching dial 800, thereby realizing the switching between the first clutch mechanism and the second clutch mechanism.

[0095] In this embodiment, the hammer drill 101 has three operating modes that can be switched via an operating mode switching dial 800: hammer drill mode, hammering mode, and drilling mode. The hammer drill mode is an operating mode in which both the hammering action and the rotary transmission mechanism 7 are driven. The hammering mode is an operating mode in which the power transmission for the drilling action is disconnected by the second clutch mechanism, and only the impact mechanism 6 is driven, thus performing only the hammering action. The drilling mode is an operating mode in which the power transmission for the hammering action is disconnected by the first clutch mechanism, and only the rotary transmission mechanism 7 is driven, thus performing only the drilling action.

[0096] As explained above, the hammer drill 101 of this embodiment has two separate intermediate shafts (a first intermediate shaft 41 and a second intermediate shaft 42), which extend parallel to the drive axis A1 and respectively transmit power for hammering and drilling actions. Therefore, compared to the case where a single common intermediate shaft is used for power transmission for both hammering and drilling actions, the first intermediate shaft 41 and the second intermediate shaft 42 can be shortened. Accordingly, the hammer drill 101 as a whole can be shortened in the axial direction.

[0097] Furthermore, the first intermediate shaft 41 and the second intermediate shaft 42 are dedicated to power transmission for hammering and drilling, respectively. Therefore, the power transmission via the first intermediate shaft 41 and the power transmission via the second intermediate shaft 42 can be optimized respectively.

[0098] Furthermore, in this embodiment, the hammer drill 101 is configured such that the transmission of vibrations (especially vibrations in the front-to-back direction) generated by the drive mechanism 5 to the main housing 10 and the handle 17 is suppressed. The vibration-damping structure of the hammer drill 101 will now be described.

[0099] In this embodiment, such as Figure 1 As shown, the main shaft 31 and the impact mechanism 6 (more specifically, the motion conversion component 61, piston 65, hammer 67, and bolt 68) are located inside the main housing 10 and are configured to move relative to the main housing 10 in the axial direction (front-back direction). More specifically, inside the main housing 10, a movable support 18 is arranged in a forward-facing position and is movable relative to the main housing 10 in the front-back direction. Furthermore, the main shaft 31 and the impact mechanism 6 are supported by the movable support 18 and are movable integrally with the movable support 18 relative to the main housing 10.

[0100] like Figure 5 , Figure 6 and Figure 12 As shown, the movable support 18 has a main shaft support portion 185 and a rotating body support portion 187. In this embodiment, the movable support 18 is configured as a single metal component.

[0101] The spindle support portion 185 is generally cylindrical and constitutes a part that supports the spindle 31. For example... Figure 5 and Figure 6As shown, a bearing 317 is held inside the spindle support portion 185. The spindle support portion 185 supports the rear portion of the cylinder 33 in a rotatable manner about the drive axis A1 via the bearing 317. Furthermore, as described above, the spindle 31 is supported on the main housing 10 in a rotatable manner about the drive axis A1 via bearings 316 and 317. The other bearing 316 is held inside the cylindrical portion 131 and supports the rear portion of the tool holder 32 in a rotatable manner about the drive axis A1 and movable in the front-rear direction.

[0102] The rotating body support 187 is a generally cylindrical portion located to the lower right of the main shaft support 185. (Example) Figure 5 As shown, a bearing 614 is fixed to the rotating body support 187 by screws. The rotating body support 187 supports the rotating body 611 in a manner that allows it to rotate about the rotation axis A3 via the bearing 614.

[0103] As described above, the main shaft 31 and the rotating body 611 are supported by the movable support 18, thereby supporting the swinging component 616 mounted on the rotating body 611 and the piston 65, hammer 67, and bolt 68 disposed within the main shaft 31. Therefore, the movable support 18, the main shaft 31, and the impact mechanism 6 constitute a movable unit 180, which is an assembly capable of moving integrally in the front-rear direction relative to the main housing 10 (in other words, the motor 2).

[0104] The movable unit 180, including the movable support 18, is slidably guided in the front-to-back direction by a pair of first guide shafts 191 and a pair of second guide shafts 192. Figure 7 and Figure 8 As shown, a pair of first guide shafts 191 and a pair of second guide shafts 192 extend coaxially along the axial direction (front-back direction).

[0105] More specifically, such as Figure 7 , Figure 8 and Figure 12 As shown, the movable support 18 has a pair of cylindrical portions 181 on the radially outer side of the main shaft support portion 185 (in Figure 12 In the middle, only one side of the cylindrical part 181 can be observed. For example... Figure 7 and Figure 8 As shown, a pair of cylindrical portions 181 are arranged symmetrically from left to right. In other words, the pair of cylindrical portions 181 are positioned relative to an imaginary plane P1 containing the drive axis A1 and the rotation axis A2 (see reference). Figure 2The cylindrical portion 181 is symmetrically arranged. Holes 183 are formed in the cylindrical portion 181, extending through it in the front-rear direction. Approximately half of the rear side of the first guide shaft 191 is pressed into each of the holes 183, and approximately half of the front side of the first guide shaft 191 extends forward from the movable support 18. Accordingly, the first guide shaft 191 is fixed to the movable support 18, configured to be able to move integrally with the movable support 18 in the front-rear direction.

[0106] The pair of first guide shafts 191 are inserted into a pair of holes 166 in the second support 16 (see reference). Figure 13 and Figure 14 (within.) More specifically, such as... Figure 7 and Figure 8 As shown, a hole 166 penetrates the second support 16 in the front-rear direction. The inner diameter of the front side of the hole 166 is larger than the inner diameter of the rear side, resulting in a step formed on the inner surface of the second support 16 forming the hole 166. The second support 16 has a cylindrical sleeve 167 inside the hole 166. The sleeve 167 is pressed into the larger diameter portion of the front side of the hole 166 such that the rear end of the sleeve 167 abuts against the step on the inner surface of the hole 166. The first guide shaft 191 is always inserted into the sleeve 167 in such a way that it slides on the inner circumferential surface of the sleeve 167 as the movable support 18 moves in the front-rear direction. The first guide shaft 191 is only in a sliding relationship with the sleeve 167 in the second support 16. In this embodiment, the front end of the sleeve 167 abuts against the front housing 13. Therefore, even if the first guide shaft 191 slides on the inner circumferential surface of the sleeve 167, the sleeve 167 will not disengage from the hole 166. In this embodiment, the sleeve 167 is formed of an ferrous metal. As described above, the portion of the second support 16 other than the sleeve 167 is formed of an aluminum metal. Therefore, according to the second support 16 including the sleeve 167, it is possible to ensure sufficient strength regarding its relative sliding with respect to the first guide shaft 191 and to ensure the overall lightweight of the second support 16.

[0107] A pair of second guide shafts 192 are located further rearward than a pair of first guide shafts 191 and are held in place by the first support 15. More specifically, as... Figure 7 , Figure 8 and Figure 11 As shown, the first support body 15 has a pair of shaft support portions 156, which extend cylindrically forward from a plate-shaped base 150 orthogonal to the front-rear direction. Approximately half of the rear side of a pair of second guide shafts 192 is pressed into the shaft support portions 156. Therefore, the pair of second guide shafts 192 cannot move relative to the first support body 15 or even the main housing 10. Approximately half of the front side of the pair of second guide shafts 192 extends forward from the first support body 15.

[0108] like Figure 7 , Figure 8 and Figure 12 As shown, the movable support 18 is coaxial with a pair of cylindrical portions 181 and has a pair of cylindrical portions 182. Holes 184 are formed in each cylindrical portion 182, penetrating the cylindrical portion 182 in the front-rear direction. The inner diameter of the rear side of the hole 184 is larger than the inner diameter of the front side, resulting in a step formed on the inner surface of the cylindrical portion 182 forming the hole 184. The movable support 18 has a cylindrical sleeve 186 within the hole 184. The sleeve 186 is pressed into the larger diameter portion of the rear side of the hole 184 such that its front end abuts against the step on the inner surface of the hole 184. The front ends of a pair of second guide shafts 192 are always inserted into the sleeve 186 such that the inner circumferential surface of the sleeve 186 slides on the second guide shaft 192 as the movable support 18 moves in the front-rear direction. The second guide shafts 192 are only in a sliding relationship with the sleeves 186 in the movable support 18. In this embodiment, the sleeve 186 is formed of a ferrous metal. As described above, the portion of the second support 16 other than the sleeve 186 is formed of an aluminum-based metal. Therefore, according to the movable support 18 including the sleeve 186, sufficient strength can be ensured regarding its relative sliding with respect to the second guide shaft 192, and the overall lightweight of the movable support 18 can be ensured. In this embodiment, the first guide shaft 191 and the second guide shaft 192 are formed of a ferrous metal.

[0109] By guiding the movable support 18 in the front-rear direction using a first guide shaft 191 and a second guide shaft 192 that are separate in the front-rear direction, the overall extension distance of the guide shaft can be shortened compared to the case where a single guide shaft extends from the position of the first guide shaft 191 to the position of the second guide shaft 192. Therefore, the hammer drill 101 can be made lighter. Furthermore, since the guide shafts are located on opposite sides of the movable support 18 in the front-rear direction, the guiding performance is not reduced along with the weight reduction.

[0110] A pair of force springs 193 are disposed rearward of the movable support 18. These force springs 193 are compression coil springs, disposed in a compressed state between the first support 15 and the movable support 18. More specifically, the pair of force springs 193 are respectively disposed around a pair of second guide shafts 192. The rear end of each force spring 193 abuts against a washer disposed on the base 150 of the first support 15. The force springs 193 are embedded around the shaft support portion 156, thereby restricting their movement in a plane orthogonal to the front-rear direction. The front end of each force spring 193 abuts against a washer 195 disposed between the force spring 193 and the movable support 18.

[0111] The sleeve 186, which is disposed in the hole 184 of the cylindrical portion 182, is always subjected to forward force through the gasket 195 by the force-applying spring 193. Therefore, when the movable support 18 moves forward, the sleeve 186 can always move together with the movable support 18. That is, when the movable support 18 moves forward, it will not leave the sleeve 186 and disengage from the hole 184.

[0112] According to this structure, a pair of force-applying springs 193 always exert a force on the movable support 18 (movable unit 180) towards the forward side. Therefore, even in the absence of an external force acting rearward on the movable support 18, such as Figure 7 As shown, the movable support 18 is also held in the foremost position (initial position) where the movable support 18 and the second support 16 abut. In addition, an elastic member may be installed on the rear surface of the second support 16 to prevent the second support 16 from directly abutting the movable support 18 (in order to mitigate the impact force).

[0113] On the other hand, when an external force is applied to the movable support 18 in a rearward direction, the movable support 18 can move to... Figure 8 The last position shown is described below. The structure that defines this last position is explained below.

[0114] like Figures 9-11 As shown, the first support 15 has a pair of elastic member retaining portions 158, which extend forward from the base 150 in a bottomed cylindrical shape. The pair of elastic member retaining portions 158 are arranged symmetrically on both sides. Holes 159 are formed in the elastic member retaining portions 158. Figure 11 As shown, the elastic member retaining portion 158 extends to a position forward of the shaft support portion 156. Cylindrical elastic members 194 are disposed in each hole 159 of the elastic member retaining portion 158. The rear end of the elastic member 194 abuts against the base 150, and the front end of the elastic member 194 protrudes to a position forward of the front end of the elastic member retaining portion 158. The elastic members 194 are held in a fitted state within the elastic member retaining portion 158. More specifically, the outer diameter of the elastic member 194 is slightly larger than the inner diameter of the elastic member retaining portion 158. Therefore, the elastic member 194 is slightly deformed radially inward within the elastic member retaining portion 158 and is held within the hole 159 by its restoring force. With this structure, the elastic member 194 can be easily installed and removed. Therefore, it is easy to manufacture, and easy to replace when the elastic member 194 deteriorates or wears out.

[0115] like Figure 9 , Figure 10 and Figure 12As shown, the movable support 18 has a pair of protrusions 188 and an abutment portion 189. The protrusions 188 extend cylindrically to a position further rearward than the cylindrical portion 182. The protrusions 188 are always inserted into the corresponding elastic member 194. The outer diameter of the protrusions 188 is slightly larger than the inner diameter of the elastic member 194. Therefore, the elastic member 194 is slightly compressed and deformed radially outward, and the protrusions 188 and the elastic member 194 remain in a fitted state by their restoring force. When the movable support 18 moves in the front-rear direction, the protrusions 188 slide on the inner surface of the elastic member 194 while maintaining their fitted state with the elastic member 194. The abutment portion 189 is arc-shaped, connecting the bases of the pair of protrusions 188, and is formed as a plane orthogonal to the front-rear direction.

[0116] When the movable support 18 is located Figure 7 When shown in the foremost position, as Figure 9 As shown, the abutment portion 189 of the movable support 18 separates from the front end of the elastic member 194 in the front-rear direction. On the other hand, when the movable support 18 is located at... Figure 8 When shown in the last position, as Figure 10 As shown, the abutment portion 189 of the movable support 18 abuts against the front end of the elastic member 194 in the front-rear direction. That is, the elastic member 194 functions as a limiting portion to restrict further rearward movement of the movable support 18. According to this structure, the movable support 18... Figure 8 The last position shown.

[0117] In the aforementioned hammer drill 101, during the hammer drill mode and hammering mode, when the tip tool 91 is pressed onto the workpiece for machining, the force driving the tip tool 91 via the impact mechanism 6 and the reaction force from the workpiece generated by the impact force of the tip tool 91 primarily produce a back-and-forth vibration on the impact mechanism 6. Through this vibration, the movable unit 180 moves relative to the main housing 10 in the back-and-forth direction while being slidably guided by the first guide shaft 191 and the second guide shaft 192. At this time, the force spring 193 extends and contracts (elastically deforms), thereby absorbing the vibration of the movable unit 180 and reducing the vibration transmitted to the main housing 10 or the handle 17. When the movable unit 180 moves to its rearmost position, the abutment portion 189 of the movable support 18 collides with the elastic member 194, causing the elastic member 194 to elastically deform, thereby absorbing the vibration of the movable unit 180.

[0118] According to the hammer drill 101 described above, bearings 411 and 421, which support the front ends of the first intermediate shaft 41 and the second intermediate shaft 42 respectively, are supported by a second metal support body 16. Therefore, compared with the case where bearings 411 and 421 are supported by a resin support body, greater support strength can be obtained. Therefore, even if the vibration caused by the reaction force of the impact force increases with the high power of the hammer drill 101, the required positional accuracy can be ensured for bearings 411 and 421, and even for the first intermediate shaft 41 and the second intermediate shaft 42. The same effect can be obtained by supporting bearings 412 and 422, which support the rear ends of the first intermediate shaft 41 and the second intermediate shaft 42 respectively, by a first metal support body 15.

[0119] Furthermore, according to the hammer drill 101, the first guide shaft 191 is partially inserted into the hole 166 of the metal second support 16 (more specifically, into the hole of the sleeve 167). Therefore, even if the heat generated when the first guide shaft 191 slides to guide the movable support 18 in the front-rear direction increases due to the increased power of the hammer drill 101, the thermal expansion of the second support 16 can be suppressed compared to the case where the first guide shaft 191 is inserted into the resin support. Therefore, the positional accuracy of the first guide shaft 191, which is partially inserted into the hole 166 of the second support 16, can be ensured. As a result, the sliding properties related to the first guide shaft 191 can be well ensured, thereby obtaining good vibration damping. The same effect can be obtained when the second guide shaft 192 is partially inserted into the hole 184 of the metal movable support 18 (more specifically, into the hole of the sleeve 186).

[0120] In this way, the hammer drill 101 can achieve both high power and low vibration. Furthermore, by using the second support body 16 as a single component to support the bearings 411 and 421 and to insert the first guide shaft 191, the device structure can be simplified and the manufacturing time can be reduced.

[0121] Furthermore, the hammer drill 101 utilizes an elastic member 194 that functions as a limiting part, which improves heat dissipation from the heat generated during the sliding movement of the movable support 18 in the front-rear direction. Its structure will now be described. (Refer to...) Figure 9 and Figure 10 As described above, the elastic member 194 is configured to always be in contact with the movable support 18 (more specifically, the protrusion 188) and the first support 15 (more specifically, the elastic member retainer 158), regardless of its position in the front-rear direction.

[0122] Furthermore, the elastic component 194 uses a thermally conductive elastic material (e.g., thermally conductive rubber). Thermal conductivity can be imparted by including fillers such as metals or carbon nanotubes in the elastic material forming the elastic component 194. "Temperaturely conductive" can be defined, for example, as having a thermal conductivity of 1.0 (W / m·K) or higher.

[0123] As described above, the first support 15 is made of metal and is disposed adjacent to the channel 26 for airflow generated by the rotation of the cooling fan 27. Therefore, the heat generated by the movable support 18 sliding in the front-back direction is transferred from the movable support 18 to the first support 15 via the thermally conductive elastic member 194, and can be efficiently dissipated by the airflow generated by the rotation of the cooling fan 27.

[0124] In this embodiment, the elastic member 194 and the protrusion 188 of the movable support 18 are always held in an engaged state. Therefore, compared to a structure where the elastic member 194 and the protrusion 188 of the movable support 18 have planar contact, the contact area between the elastic member 194 and the movable support 18 is larger. Therefore, the heat transfer capacity from the movable support 18 to the elastic member 194 is improved, further enhancing heat dissipation. Furthermore, the elastic member 194 and the elastic member holding portion 158 of the first support 15 are always held in an engaged state. Therefore, compared to a structure where the elastic member 194 and the elastic member holding portion 158 of the first support 15 have planar contact, the contact area between the elastic member 194 and the first support 15 is larger. Therefore, the heat transfer capacity from the elastic member 194 to the first support 15 is improved, further enhancing heat dissipation. Moreover, these engaged states are achieved by engaging a cylindrical shape with a cylindrical shape or a cylindrical shape. Therefore, while ensuring a large contact area, ease of manufacturing is achieved.

[0125] And, as Figure 11 As shown, the elastic member 194 is positioned adjacent to the second guide shaft 192. Therefore, the heat transfer distance from the point where heat is generated due to sliding to the elastic member 194 via the movable support 18 can be shortened. Thus, heat dissipation can be performed more effectively.

[0126] And, as Figure 11As shown, in an imaginary plane orthogonal to the drive axis A1 (in other words, the surface of the base 150 unfolded), the distance between the right side of one of the pair of second guide shafts 192 and the right side of one of the pair of elastic members 194 is equal to the distance between the left side of the other of the pair of second guide shafts 192 and the left side of the other of the pair of elastic members 194, wherein the right side of one of the pair of elastic members 194 is adjacent to the right side of the other of the pair of second guide shafts 192. Therefore, the distance of the heat transfer path from one of the second guide shafts 192 to one of the elastic members 194 is equal to the distance of the heat transfer path from the other of the second guide shafts 192 to the other of the elastic members 194 (this configuration is also referred to as an equidistant configuration). Therefore, temperature unevenness in the movable support 18 is suppressed, thereby enabling uniform heat dissipation.

[0127] exist Figure 11 In the example shown, an equidistant arrangement is illustrated where one elastic member 194 corresponds to one second guide shaft 192. However, in alternative embodiments, multiple elastic members 194 may also correspond to one second guide shaft 192. For example, when two elastic members 194 correspond to one second guide shaft 192 (in which case the total number of elastic members 194 is four), an equidistant arrangement can be achieved such that the distance between one second guide shaft 192 and its corresponding two elastic members 194 is equal to the distance between the other second guide shaft 192 and its corresponding two elastic members 194.

[0128] The following shows the correspondence between the structural elements of the above embodiments and the structural elements of the technical solutions. However, each structural element of the embodiments is merely an example and does not limit the present invention. The hammer drill 101 is an example of an "impact tool". The spindle 31 is an example of a "final output shaft". The drive shaft A1 is an example of a "drive shaft". The motor 2 and motor shaft 25 are examples of a "motor" and a "motor shaft", respectively. The drive mechanism 5 is an example of a "drive mechanism". The main body housing 10 is an example of a "housing". The movable support 18 is an example of a "movable support". The force-applying spring 193 is an example of a "force-applying component". The first guide shaft 191 and the second guide shaft 192 are examples of a "first guide shaft" and a "second guide shaft", respectively. The first intermediate shaft 41 and the second intermediate shaft 42 are examples of a "first intermediate shaft" and a "second intermediate shaft", respectively. The bearing 411 and the bearing 421 are examples of a "first bearing" and a "second bearing", respectively. The second support 16 is an example of a "metal support". Holes 166 and 184 are examples of "first hole" and "second hole", respectively. The first positioning part 163 and the second positioning part 133 are examples of "first positioning part" and "second positioning part", respectively. Sleeves 167 and 186 are examples of "first sleeve" and "second sleeve", respectively. The mounting surface 168 is an example of a "mounting surface".

[0129] Furthermore, the above embodiments are merely examples, and the impact tool involved in this invention is not limited to the structure of the example hammer drill 101. For example, the following examples of modifications can be added. Any one or more of these modifications can be used in combination with the hammer drill 101 shown in the embodiments or the methods described in the various technical solutions.

[0130] Alternatively, instead of the first intermediate shaft 41 and the second intermediate shaft 42, a single intermediate shaft that serves as both the power transmission for hammering and the power transmission for drilling can be used. Such a structure is described, for example, in U.S. Patent Application Publication No. 2017 / 106517. The entire disclosure of U.S. Patent Application Publication No. 2017 / 106517 is incorporated herein by reference.

[0131] Instead of the first guide shaft 191 being fixedly held in the movable support 18, the first guide shaft 191 can also be fixedly inserted into the hole 166 of the second support 16. In this case, the first guide shaft 191 held by the second support 16 can also be slidably inserted into the hole formed in the movable support 18.

[0132] The contact between the movable support 18, the elastic member 194, and the first support 15 can be varied in any manner. For example, the elastic member retaining portion 158 may be cylindrical, the elastic member 194 may be cylindrical surrounding the elastic member retaining portion 158, and the protrusion 188 may be cylindrical surrounding the elastic member 194. Alternatively, the movable support 18, the elastic member 194, and the first support 15 may be in planar contact.

[0133] A thermally conductive elastic member (elastic member 194 in the above embodiment) is configured to always be in contact with the movable support 18 and any metal member configured to dissipate heat. In this case, the metal member may also extend from the front side of the first support 15 through the first support 15 and into the airflow passage 26. Alternatively, the metal member may be any member configured to be at least partially exposed to the outside of the hammer drill 101. For example, at least a portion of the exposed part of the main housing 10 may be made of metal, and this metal portion and the elastic member may be configured to always be in contact.

[0134] In the above embodiments, a hammer drill 101 capable of performing both hammering and drilling actions is exemplified as an impact tool. However, the impact tool could also be an electric hammer capable of performing only hammering actions.

[0135] Furthermore, in the impact tool, the following methods 1 to 10 are constructed to improve heat dissipation for heat generated by sliding between components. Any one of the following methods 1 to 10 may be used alone, or two or more of the following methods 1 to 10 may be combined. Alternatively, at least one of the following methods 1 to 10 may be used in combination with the hammer drill 101 of the embodiment, the above-described modifications, and at least one of the methods described in each technical solution.

[0136] [Method 1]

[0137] An impact tool,

[0138] It comprises a final output shaft, a motor, a drive mechanism, a movable support, a force-applying component, at least one guide shaft, a metal component, and at least one elastic component, wherein,

[0139] The final output shaft is configured to hold the top tool in a detachable manner, and the drive axis of the top tool is defined.

[0140] The motor has a motor shaft;

[0141] The drive mechanism is configured to drive the top tool in a straight line along the drive axis by the power of the motor;

[0142] The movable support at least partially supports the final output shaft and the drive mechanism, and is configured to move integrally with respect to the motor along the axial direction of the drive axis;

[0143] When the side in the axial direction where the final output shaft is configured is defined as the front side and the side where the motor is configured is defined as the rear side, the force-applying component applies a force to the movable support body in the axial direction towards the front side.

[0144] The at least one guide shaft is configured to extend along the axial direction and slide to guide the movable support body to move along the axial direction.

[0145] The metal component is configured to dissipate heat;

[0146] The at least one elastic member is thermally conductive, and the at least one elastic member is configured to always be in contact with the movable support and the metal component, regardless of the position of the movable support in the axial direction.

[0147] According to this method, in the impact tool, at least one thermally conductive elastic member is always in contact with the movable support and the metal component configured for heat dissipation. Therefore, heat generated by sliding to guide the movement of the movable support can be transferred from the movable support to the metal component via the at least one elastic member for heat dissipation. Thus, heat dissipation can be improved against the heat generated by sliding to guide the movement of the movable support.

[0148] [Method 2]

[0149] The impact tool according to method 1

[0150] The metal component is configured to be at least partially exposed to the outside of the impact tool.

[0151] According to this method, heat transferred from the movable support to the metal component can be dissipated through a simple structure. In this method, the metal component can also be part of a housing that defines the outer contour of the impact tool.

[0152] [Method 3]

[0153] The impact tool according to method 1 or method 2

[0154] It also includes a fan, which is configured on the motor shaft.

[0155] The metal component is positioned on or adjacent to the airflow channel generated by the rotation of the fan.

[0156] According to this method, the heat transferred from the movable support to the metal parts can be efficiently dissipated by utilizing the airflow generated by the rotation of the fan.

[0157] [Method 4]

[0158] The impact tool according to any one of methods 1 to 3

[0159] The at least one elastic member is held in place by the metal member.

[0160] The movable support is configured to slide on at least one elastic member as it moves along the axial direction.

[0161] According to this method, it is easy to achieve a situation where at least one elastic component is always in contact with the movable support and the metal component.

[0162] [Method 5]

[0163] The impact tool according to any one of methods 1 to 4

[0164] The at least one elastic component and the movable support are always kept in an engaged state.

[0165] According to this method, compared to the case where at least one elastic member and the movable support have planar contact, the contact area between at least one elastic member and the movable support is increased. Therefore, the ability to transfer heat from the movable support to at least one elastic member is improved, thereby enhancing heat dissipation.

[0166] [Method 6]

[0167] According to the impact tool of method 5, the shape of the at least one elastic member and the movable support body is formed such that the fitting state of the at least one elastic member and the movable support body is achieved by fitting a cylindrical shape with a cylindrical shape or a cylindrical shape.

[0168] According to this method, it is possible to ensure that at least one elastic component has a large contact area with the movable support, while also being easy to manufacture.

[0169] [Method 7]

[0170] The impact tool according to any one of methods 1 to 6

[0171] The at least one elastic member is configured adjacent to the at least one guide shaft.

[0172] According to this method, the heat transfer distance from the heat-generating location in the movable support due to sliding to at least one elastic member can be shortened. Therefore, heat dissipation can be achieved efficiently.

[0173] [Method 8]

[0174] The impact tool according to any one of methods 1 to 7

[0175] The at least one elastic member functions as a limiting part. When the movable support moves to the rearward side in the axial direction, the limiting part abuts against the movable support in the axial direction, restricting the movable support from moving further to the rearward side.

[0176] According to this method, by means of the elastic deformation of at least one elastic member acting as a limiting part, a portion of the reaction force received from the workpiece during the hammering action of the tip tool is buffered. Therefore, the low vibration performance of the impact tool can be improved. Furthermore, the durability of the device is also improved.

[0177] [Method 9]

[0178] The impact tool according to any one of methods 1 to 8

[0179] The at least one guide shaft has multiple guide shafts.

[0180] The at least one elastic component has multiple elastic components corresponding to the multiple guide shafts.

[0181] The at least one guide shaft and the at least one elastic member are configured such that the distances between the plurality of guide shafts on the imaginary surface orthogonal to the drive axis and the corresponding elastic members (which may be one or more) are equal to each other.

[0182] According to this method, the distances (i.e., the distances of the heat transfer paths) between the multiple guide shafts and their corresponding elastic components are equal, thus suppressing temperature unevenness in the movable support and enabling uniform heat dissipation.

[0183] [Method 10]

[0184] The impact tool according to any one of methods 1 to 9

[0185] The metal component has at least one hole.

[0186] The at least one elastic member is held in the at least one hole in an engaged state.

[0187] According to this method, compared to the case where at least one elastic component and a metal component have planar contact, the contact area between at least one elastic component and the metal component is increased. Therefore, the heat transfer capacity from at least one elastic component to the metal component is improved, thereby enhancing heat dissipation. Furthermore, the at least one elastic component can be easily disassembled and assembled relative to the metal component. Therefore, it is easy to manufacture and easy to replace when the at least one elastic component deteriorates or wears out.

[0188] The following shows the correspondence between the structural elements of the above embodiments and the structural elements of methods 1 to 10. However, each structural element of the embodiments is merely an example and does not limit the present invention.

[0189] Hammer drill 101 is an example of an "impact tool". Spindle 31 is an example of a "final output shaft". Drive shaft A1 is an example of a "drive shaft". Motor 2 and motor shaft 25 are examples of a "motor" and a "motor shaft", respectively. Drive mechanism 5 is an example of a "drive mechanism". Movable support 18 is an example of a "movable support". Force spring 193 is an example of a "force-applying component". Second guide shaft 192 (or second guide shaft 192 and first guide shaft 191) is an example of "at least one guide shaft". First support 15 is an example of a "metal component". Elastic component 194 is an example of "at least one elastic component". Cooling fan 27 is an example of a "fan".

Claims

1. An impact tool, characterized in that, It comprises a final output shaft, a motor, a drive mechanism, a housing, a movable support, a force-applying component, a first guide shaft, at least one intermediate shaft, at least one bearing, and a single metal support, wherein... The final output shaft is configured to retain the top tool in a detachable manner and defines the drive axis of the top tool; The motor has a motor shaft; The drive mechanism is configured to perform a hammering action by driving the top tool in a straight line along the drive axis using the power of the motor. The housing houses the motor and the drive mechanism; The movable support at least partially supports the final output shaft and the drive mechanism, and the movable support is configured to move integrally with respect to the housing along the axial direction of the drive axis. When the side in the axial direction where the final output shaft is configured is defined as the front side and the side where the motor is configured is defined as the rear side, the force-applying component applies a force to the movable support body in the axial direction towards the front side. The first guide shaft is configured to extend along the driving direction to slide and guide the movable support body to move along the axial direction. The at least one intermediate shaft extends along the axial direction, and the at least one intermediate shaft is configured to rotate along with the rotation of the motor shaft, thereby transmitting the power of the motor to the drive mechanism; The at least one bearing supports the front end of the at least one intermediate shaft in the axial direction; The single metal support is configured not to move relative to the housing and supports the at least one bearing, and the single metal support has a first hole in which the first guide shaft is partially inserted.

2. The impact tool according to claim 1, characterized in that, The shell is made of resin. The metal support is fixed to the housing.

3. The impact tool according to claim 1, characterized in that, The metal support has a first positioning portion on its front side, which is configured to surround the final output shaft in the circumferential direction. The housing has a second positioning portion configured to surround the final output shaft in the circumferential direction. The first positioning part and the second positioning part are shaped to match each other in a way that they fit together in the axial direction.

4. The impact tool according to claim 2, characterized in that, The metal support has a first positioning portion on its front side, which is configured to surround the final output shaft in the circumferential direction. The housing has a second positioning portion configured to surround the final output shaft in the circumferential direction. The first positioning part and the second positioning part are shaped to match each other in a way that they fit together in the axial direction.

5. The impact tool according to claim 3, characterized in that, The metal support has a mounting surface on its front side, which unfolds on a single plane at a position radially outward from the first positioning part. The mounting surface abuts against the housing in the axial direction.

6. The impact tool according to claim 1, characterized in that, The first guide shaft is configured to be located at least partially forward of the movable support. The impact tool also has a second guide shaft, which is coaxially arranged with the first guide shaft in such a manner that it is at least partially located behind the movable support.

7. The impact tool according to claim 6, characterized in that, The first guide shaft extends forward from the movable support and is configured to move integrally with the movable support along the axial direction.

8. The impact tool according to claim 7, characterized in that, The metal support body has a first sleeve made of ferrous metal inside the first hole. The first guide shaft is configured to slide on the inner circumferential surface of the first sleeve as the movable support moves along the axial direction. Except for the first sleeve, the metal support body is formed of aluminum-based metals.

9. The impact tool according to claim 6, characterized in that, The movable support has a second hole and a second sleeve, wherein the second guide shaft is partially inserted into the second hole; and the second sleeve is disposed within the second hole. The second guide shaft is configured to be immovable relative to the housing. The inner circumferential surface of the second sleeve is configured to slide on the second guide shaft as the movable support moves along the axial direction. The force-applying component is positioned rearward of the movable support body in the axial direction, around the second guide shaft, and is configured to apply force integrally to the movable support body including the second sleeve in the forward direction.

10. The impact tool according to any one of claims 1 to 9, characterized in that, The drive mechanism is further configured to drive a drilling action by rotating the tip tool around the drive axis via the power of the motor. The at least one intermediate shaft has a first intermediate shaft and a second intermediate shaft, wherein the first intermediate shaft is configured to transmit power for the hammering action to the drive mechanism, and the second intermediate shaft is configured to transmit power for the drilling action to the drive mechanism. The at least one bearing has a first bearing supporting the first intermediate shaft and a second bearing supporting the second intermediate shaft. The first intermediate shaft is configured to transmit the hammering action but not the drilling action. The second intermediate shaft is configured to transmit the drilling action but not the hammering action.

11. The impact tool according to claim 10, characterized in that, The first bearing and the second bearing are respectively arranged at offset positions in the axial direction.

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