Impact tools

Abstract

There is a need for striking tools that can increase the impact force with which a hammer strikes a target object such as a screwdriver. [Solution] The striking tool 1 has a spindle 24 that rotates axially by a motor 20, a reduction mechanism 21 that reduces the output from the spindle 24, and a carrier 27 that rotates axially by the output of the reduction mechanism 21. The striking tool 1 has a hammer 31a that is movable axially and circumferentially relative to the carrier 27, a spring 33 that contacts the hammer 31a at its first end 33a, an assist member 24c that contacts the second end 33b of the spring 33 and rotates integrally with the spindle 24, and a driver 35 that is struck by the hammer 31a. When the hammer 31a returns axially and rotates circumferentially by utilizing the elastic force of the spring 33 which has elastically deformed by the axial movement of the hammer 31a, the second end 33b of the spring 33 rotates circumferentially in the same direction as the hammer 31a by the assist member 24c, and the hammer 31a strikes the driver 35.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an impact tool including an impact mechanism that strikes a counterpart member such as a driver with a hammer rotated by the output of a motor, for example. BACKGROUND ART

[0002] Patent Documents 1 and 2 disclose, as an example of an impact tool, a driving tool referred to as a so-called loose nail driver. The impact tool has an impact mechanism including a hammer that is rotated by the output of a motor. The hammer repeatedly moves in the axial direction between an impact position and a retracted position while rotating about its axis. Each of the hammer and a rotating member that transmits rotational power to the hammer is provided with a cam groove inclined with respect to the axial direction. A ball is interposed between the cam grooves of the two members. The hammer is guided by the engagement between the ball and the cam grooves, so that the hammer moves in the axial direction while rotating about its axis relative to the rotating member.

[0003] Moreover, the hammer is biased toward the impact position side in the axial direction by a spring. When the hammer abuts against the driver at the impact position, the hammer attempts to push the driver in the impact direction by the rotational power of the rotating member and the biasing force of the spring. When the driver cannot be pushed further in the impact direction, the hammer moves to the retracted position in the axial direction against the biasing force of the spring, and is guided by the engagement between the ball and the cam grooves to rotate about its axis in the direction opposite to the rotation direction of the rotating member. The spring accumulates energy by being compressed. When the driver is completely disengaged, the hammer is guided by the engagement between the ball and the cam grooves while moving to the impact position in the axial direction by the energy accumulated in the spring, and rotates about its axis in the rotation direction of the rotating member. The driver is struck in the impact direction by the rotating hammer. By repeating this series of operations, the hammer repeatedly strikes the driver.

[0004] The rotating member disclosed in Patent Document 1 is a shaft member inserted radially inward into the hammer. The spring engages with the hammer at the striking position end and engages with a flange-shaped spring receiving portion that extends radially outward from the rotating member at the retracted position end. The hammer moves to the striking position while rotating axially in the striking direction, utilizing the energy stored in the spring. Therefore, at the time of impact, the hammer collides with the driver at a speed faster than the rotational speed of the rotating member.

[0005] The rotating member disclosed in Patent Document 2 is a cylindrical member inserted radially inward into the hammer. A fixed shaft is inserted further radially inward into the rotating member. The spring engages with the hammer at the striking position end and engages with a flange-shaped receiving portion that extends radially outward from the fixed shaft at the retracted position end. Because the spring is engaged with the fixed shaft at one end, it creates resistance that tries to return the hammer to the opposite direction of impact when the hammer rotates axially in the striking direction. As a result, the impact force with which the hammer strikes the driver is reduced. There is room for improvement in Patent Document 1 as well to increase the impact force of the hammer. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] U.S. Patent No. 8342375 [Patent Document 2] U.S. Patent No. 8,297,373 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Therefore, there is a need for a striking tool that can increase the impact force with which a hammer strikes a target object such as a screwdriver. [Means for solving the problem]

[0008] According to one feature of this disclosure, the striking tool comprises a spindle, a reduction mechanism, and a carrier. The spindle is axially rotated by a motor. The reduction mechanism reduces the output from the spindle. The carrier is axially rotated by the output of the reduction mechanism. The striking tool comprises a hammer, a spring, an assist member, and a driver. The hammer is mounted to be movable axially and circumferentially relative to the carrier. The spring contacts the hammer at its first end. The assist member contacts the second end of the spring and rotates integrally with the spindle. The driver is struck by the hammer. When the hammer returns axially and rotates circumferentially using the elastic force of the spring, which has elastically deformed by the axial movement of the hammer, the second end of the spring rotates circumferentially in the same direction as the hammer by the assist member, causing the hammer to strike the driver.

[0009] Therefore, the assist member rotates axially at the same rotational speed as the spindle upstream of the reduction mechanism. As a result, the assist member can rotate axially at a faster speed than the carrier and hammer downstream of the reduction mechanism. This causes the carrier and hammer to rotate axially in the striking direction, following the second end of the spring held by the assist member. This increases the rotational speed of the carrier and hammer. Thus, the striking force with which the hammer strikes the driver can be increased. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view of a driving tool according to the first embodiment of the present disclosure. [Figure 2] This is a right side view of the driving tool. [Figure 3] This is a right-side view of the drive tool, excluding the right side of the outer housing. [Figure 4] This is a perspective view of the inner housing of the tool body after disassembly. [Figure 5] This is a disassembled perspective view of the motor, reduction gear, and impact mechanism. [Figure 6] Figure 2 shows a cross-sectional view of the rotating member at the impact position, along the line VI-VI. [Figure 7]This is a side view of the striking mechanism when the rotating member is in the striking position. [Figure 8] This is a cross-sectional view taken along the VI-VI line in Figure 2, when the rotating member is in the retracted position. [Figure 9] This is a side view of the striking mechanism when the rotating member is in the retracted position. [Figure 10] This is a cross-sectional view taken along the X-X line in Figure 6, before striking. [Figure 11] This is a cross-sectional view taken along the XI-XI line in Figure 6, when the rotating member is in the striking position. [Figure 12] This is a cross-sectional view taken along the XI-XI line in Figure 6, when the rotating member is in the retracted position. [Figure 13] This is a cross-sectional view taken along the X-X line in Figure 6, immediately before the driver strikes. [Figure 14] This is a cross-sectional view taken along the X-X line in Figure 6, immediately after the driver strikes. [Figure 15] This is a cross-sectional view taken along the XV-XV line in Figure 3, when the switch operation part is in the initial position. [Figure 16] This is a cross-sectional view taken along the XV-XV line in Figure 3, when the switch operation part is pressed. [Figure 17] This is a right side view of the driving tool according to the second embodiment. [Figure 18] This is a right side view of the driving tool excluding the right part of the outer housing. [Figure 19] This is a cross-sectional arrow view taken along the XIX-XIX line in Figure 17. [Figure 20] This is an exploded perspective view of the inner housing of the tool main body. [Figure 21] This is a right side view of the driving tool according to the third embodiment. [Figure 22] This is a perspective view of the driving tool according to the fourth embodiment. [Mode for Carrying Out the Invention]

[0011] According to other features of this disclosure, the spindle, carrier, and spring are arranged coaxially. Therefore, the spindle, carrier, and spring each rotate around the same axis. As a result, the rotational speed of the carrier can be efficiently increased to follow the rotation of the spring. In addition, the spindle, carrier, and spring can be arranged compactly. This allows the striking mechanism of the striking tool to be compactly provided in an axially symmetric shape.

[0012] According to other features of this disclosure, the carrier is positioned outside the spindle. The spindle is equipped with a sun gear of a planetary reduction gear, which is a reduction mechanism. Therefore, by using a planetary reduction gear between the spindle and the carrier, the reduction mechanism and the striking mechanism can be compactly provided in an axisymmetric shape.

[0013] According to other features of this disclosure, a spring is positioned on one axial side of the hammer. A reduction mechanism is positioned on the other axial side of the hammer. Therefore, the reduction mechanism and the striking mechanism can be compactly arranged in the axial direction. Moreover, the carrier can be positioned in the axial center between the spring and the reduction mechanism. As a result, the hammer and driver can also be positioned in the axial center, similar to the carrier. This brings the position where the reaction force is generated when the hammer strikes the driver closer to the center of gravity of the tool body. Thus, it is possible to suppress the tilting of the driver's striking direction due to the reaction force when the hammer strikes the driver.

[0014] According to other features of this disclosure, the spindle penetrates the carrier axially. The spindle has a sun gear on its base end. An assist member is provided on the tip end of the spindle. Therefore, the carrier and spring are arranged coaxially with the spindle and are positioned between the sun gear and the assist member in the axial direction. This allows for the compact provision of an assist mechanism that increases the rotational speed of the carrier and hammer in accordance with the axial rotation of the spring.

[0015] According to other features of this disclosure, the spindle is provided with an anti-rotation member. The anti-rotation member restricts the assist member from rotating relative to the spindle. Therefore, the assist member rotates axially integrally with the spindle. This allows the assist member to rotate axially at the high rotational speed before deceleration in the reduction mechanism. This allows the carrier and hammer to rotate axially more quickly in the striking direction, following the axial rotation of the spring.

[0016] According to other features of this disclosure, the spindle is provided with a thrust bearing that supports the carrier so that it can rotate axially. Thus, the carrier can rotate smoothly axially at a different rotational speed from the spindle.

[0017] According to other features of this disclosure, a radial bearing is provided between the spindle and the carrier in the radial direction. Thus, the spindle and the carrier can be stably rotated at different rotational speeds.

[0018] Other features of this disclosure involve assembling the spindle, reduction mechanism, carrier, hammer, and spring. This improves the workability when assembling the striking tool.

[0019] According to other features of this disclosure, the striking tool has a grip portion. The grip portion is positioned on the opposite side of the screwdriver and on the axis of the direction of impact of the screwdriver. Therefore, the grip portion held by the operator is positioned on the line of force of the reaction force generated when the hammer strikes the screwdriver. This prevents the tool body and the screwdriver from tilting relative to the direction of impact due to the reaction force.

[0020] Next, a first embodiment of the present invention will be described with reference to Figures 1 to 16. In this disclosure, a driving tool 1, referred to as a loose nail gun, is given as an example of a driving tool or striking tool. The driving tool 1 drives a driving tool, such as a nail, into the material to be driven by repeatedly striking the head of the driving tool with a screwdriver. In the following description, the direction of striking with the screwdriver is downward, and the opposite direction is upward. The front, back, left, and right directions are based on the direction as seen from the user located behind the driving tool 1.

[0021] As shown in Figure 1, the tool body 2 of the driving tool 1 is covered by an outer housing (main housing) 3 that has a housing front and is long in the front-to-back direction. The outer housing 3 has a split structure that can be divided into left and right halves. A grip portion 3a is provided on the upper surface of the outer housing 3. The driving tool 1 of this disclosure is called a so-called palm grip type. The user grasps the grip portion 3a by covering it from above with their hand. A cylindrical guide portion 3h is provided on the front lower surface of the outer housing 3. A cylindrical nail guide 37 protrudes downward from the guide portion 3h. An opening 37a is provided at the lower end of the nail guide 37. The opening 37a is located in the center of the left and right sides of the lower part of the outer housing 3.

[0022] As shown in Figure 10, the driving tool (the member to be struck) N is attached to the inner circumference of the nail guide 37. The driving tool N is attached in a position with its head facing upwards and its legs protruding from the opening 37a. The legs of the driving tool N are brought into contact with the material to be driven W. By repeatedly striking the head of the driving tool N with the driver 35 inside the tool body 2, the driving tool N is driven into the material to be driven W.

[0023] As shown in Figure 2, a circular exposed opening 3b is provided on the right side of the outer housing 3. The right side of the motor housing 5, which will be described later, is exposed to the outside of the outer housing 3 through the exposed opening 3b. The exposed opening 3b has a larger diameter than the motor housing 5 so as not to come into direct contact with the motor housing 5. A projection 3c is provided on the lower part of the outer housing 3, extending downwards. The projection 3c is located behind the guide portion 3h and below and in front of the battery mounting portion 10, which will be described later. An illuminator 15 is provided on the projection 3c. The illuminator 15 includes a light-emitting element that emits light when power is supplied, such as an LED. The illuminator 15 irradiates light toward the area below the opening 37a.

[0024] As shown in Figure 2, a battery mounting section 10 is provided on the rear surface of the outer housing 3. A rechargeable battery 11 can be detachably mounted in the battery mounting section 10. The battery 11 is, for example, a lithium-ion battery with an output voltage of 10.8V. The battery 11 can be removed from the battery mounting section 10 and recharged repeatedly using a separately provided charger. The battery 11 can be reused as a power source between other rechargeable power tools such as screw tighteners and electric drills.

[0025] As shown in Figure 3, the battery mounting section 10 is provided with rails 10a and connection terminals 10b. Rails 10a extend vertically from the right and left ends of the battery mounting section 10. Connection terminals 10b extend vertically between the left and right rails 10a, approximately parallel to the rails 10a, and protrude rearward from the battery mounting section 10. The battery 11 can be mounted in the battery mounting section 10 by sliding it from top to bottom along the rails 10a. The battery 11 can be removed from the battery mounting section 10 by sliding it from bottom to top along the rails 10a.

[0026] As shown in Figure 1, the upper front surface of the outer housing 3 is provided with a curved surface portion 3d having curvature in the vertical and horizontal directions. A through hole 3e is provided, surrounded by the curved surface portion 3d. The through hole 3e is rectangular in shape and penetrates the outer housing 3 in the front-to-back direction. The switch operating lever 12 is inserted through the through hole 3e. The switch operating lever 12 is slidable in the front-to-back direction and biased forward. The front surface of the switch operating lever 12 is the switch operating portion 12a. The switch operating portion 12a is located at the left-right center of the front surface of the outer housing 3, adjacent to the grip portion 3a. The switch operating portion 12a operates the electric switch 13 of the motor 20, which will be described later. The user can operate the switch operating portion 12a by hooking the fingers of the hand gripping the grip portion 3a onto the switch operating portion 12a and pulling it backward. As shown in Figure 2, when the switch operating portion 12a is not pulled backward, it is located in front of the curved surface portion 3d. As shown in Figure 16, the switch operating section 12a protrudes slightly forward from the curved surface section 3d when pulled backward.

[0027] As shown in Figure 2, a lock lever 14 is provided on the upper rear of the tool body 2. The lock lever 14 is located below and behind the grip portion 3a and in front of the battery mounting portion 10. The lock lever 14 moves in the left-right direction and interferes with the arm 12b of the switch operating portion 12a, which will be described later. The lock lever 14 can slide relative to the outer housing 3 by being pushed in the left-right direction. By sliding the lock lever 14 left or right, it is possible to switch between an unlocked state in which the pull operation of the switch operating portion 12a is effective and a locked state in which the pull operation of the switch operating portion 12a is restricted.

[0028] As shown in Figure 3, the driving tool 1 has an inner housing 4 inside the outer housing 3. The inner housing 4 houses assembled mechanical parts such as the motor 20, reduction mechanism 21, and impact mechanism 30. The motor rotation axis J1 of the motor 20, the intermediate shaft rotation axis (idle gear rotation axis) J2 of the idler gear 23a (see Figure 6) of the reduction mechanism 21, and the hammer rotation axis J3 of the impact mechanism 30 extend in the left-right direction, approximately parallel to each other. The driver movement axis (impact axis) J4 on which the driver 35 (see Figure 10) moves extends in the vertical direction, approximately perpendicular to the motor rotation axis J1, idler gear rotation axis J2, and hammer rotation axis J3. The grip portion 3a is positioned on the upper extension of the driver movement axis J4.

[0029] As shown in Figure 3, the intermediate shaft rotation axis J2 is located between the driver movement axis J4 and the motor rotation axis J1 in the front-rear direction. The intermediate shaft rotation axis J2 is positioned below the motor rotation axis J1. The hammer rotation axis J3 is located in front of the driver movement axis J4. The hammer rotation axis J3 is positioned above the motor rotation axis J1. The motor rotation axis J1 and the intermediate shaft rotation axis J2 are positioned to overlap vertically with the striking mechanism 30 and the battery mounting section 10. The hammer rotation axis J3 is positioned to overlap vertically with the battery mounting section 10.

[0030] As shown in Figure 4, the inner housing 4 is provided by integrally assembling the motor housing 5, gear housing 6, and hammer housing 7 with a plurality of fastening members 8. The motor housing 5 is cylindrical with a bottom surface on the right side and an opening on the left side. A ventilation opening 5a is provided on the bottom surface of the motor housing 5 that penetrates from the inside to the outside. A plurality of bosses 5b are provided on the outer circumferential surface of the left side of the motor housing 5, protruding radially outward. The bosses 5b are cylindrical and extend in the left-right direction. Female threaded portions 5c are provided on the inner circumferential surface of the bosses 5b, extending in the left-right direction. The motor 20 is housed inside the motor housing 5.

[0031] As shown in Figure 4, the gear housing 6 has a motor cap portion 6a, an idler gear housing portion 6b, and a spindle housing portion 6c. The motor cap portion 6a, the idler gear housing portion 6b, and the spindle housing portion 6c are integrally connected. The motor cap portion 6a is disc-shaped and covers the motor housing 5 and the clamping portion 7a (described later) from the left. The idler gear housing portion 6b is connected to the front of the motor cap portion 6a. The idler gear housing portion 6b is cylindrical with a bottom on the left side and an opening on the right side. The intermediate shaft 23 and the idler gear 23a (described later) are housed in the idler gear housing portion 6b (see Figure 6). The spindle housing portion 6c is connected to the front of the idler gear housing portion 6b. The spindle housing portion 6c is cylindrical with a bottom on the left side and an opening on the right side. The spindle housing portion 6c houses the spindle 24 (described later) and the left part of the planetary reduction mechanism 22 (see Figure 6).

[0032] As shown in Figure 4, the outer circumferential surface of the motor cap portion 6a is provided with a plurality of bosses 6d that protrude radially outward. The bosses 6d are cylindrical in shape and extend in the left-right direction. The bosses 6d are provided with through holes 6f that penetrate in the left-right direction. The outer circumferential surface of the spindle housing portion 6c is provided with a plurality of bosses 6e that protrude radially outward. The bosses 6e are cylindrical in shape and extend in the left-right direction. The bosses 6e are provided with through holes 6g that penetrate in the left-right direction.

[0033] As shown in Figure 4, the hammer housing 7 has a clamping portion 7a, an idler gear housing portion 7b, and a striking mechanism housing portion 7c. The clamping portion 7a, the idler gear housing portion 7b, and the striking mechanism housing portion 7c are integrally connected. The clamping portion 7a is disc-shaped and covers the motor housing 5 from the left. The idler gear housing portion 7b is connected to the front of the clamping portion 7a. The idler gear housing portion 7b is disc-shaped and covers the idler gear housing portion 6b of the gear housing 6 from the right (see Figure 3). As shown in Figure 6, the idler gear housing portion 7b works together with the idler gear housing portion 6b to house the intermediate shaft 23 and the idler gear 23a, which will be described later. In other words, the idler gear housing portion 7b also serves as the gear housing.

[0034] As shown in Figure 4, the impact mechanism housing 7c is connected to the front of the idler gear housing 7b. The impact mechanism housing 7c is cylindrical, with its bottom on the right side and an opening on the left side. As shown in Figure 6, the impact mechanism housing 7c works in cooperation with the spindle housing 6c to house the right side of the planetary reduction mechanism 22 (described later) and the impact mechanism 30. In other words, the spindle housing 6c also serves as the hammer housing.

[0035] As shown in Figure 4, the outer circumferential surface of the clamping portion 7a is provided with a plurality of bosses 7d that protrude radially outward. The bosses 7d are cylindrical in shape and extend in the left-right direction. The bosses 7d are provided with through holes 7f that penetrate in the left-right direction. The outer circumferential surface of the striking mechanism housing portion 7c is provided with a plurality of bosses 7e that protrude radially outward. The bosses 7e are cylindrical in shape and extend in the left-right direction. The inner circumferential surface of the bosses 7e is provided with a female thread portion 7g that extends from the left end to the right.

[0036] As shown in Figure 4, multiple male screws 8a are inserted from left to right through each through-hole 6f of the gear housing 6 and each through-hole 7f of the hammer housing 7 as fastening members 8. The multiple male screws 8a are fastened to each female threaded portion 5c of the motor housing 5. Multiple hex socket head bolts 8b are inserted from left to right through each through-hole 6g of the gear housing 6 as fastening members 8. The multiple hex socket head bolts 8b are fastened to each female threaded portion 7g of the hammer housing 7. As shown in Figure 6, the male screws 8a fasten the three members together with the clamping portion 7a sandwiched between the motor housing 5 and the motor cap portion 6a in the left-right direction. The clamping portion 7a and the motor cap portion 6a cover the left opening of the motor housing 5. In other words, the clamping portion 7a and the motor cap portion 6a also serve as the motor housing that houses the motor 20.

[0037] As shown in Figure 4, the upper outer surface of the hammer housing 7 is provided with upper protrusions 7h and 7i that project upward. The lower outer surface of the hammer housing 7 is provided with a lower protrusion 7j that projects downward. The upper protrusions 7h, 7i and the lower protrusion 7j are cylindrical in shape with their axial direction in the vertical direction. As shown in Figure 3, the upper protrusion 7h and the lower protrusion 7j are positioned vertically and aligned with the driver movement axis J4 as the center. The lower protrusion 7j encloses the driver guide 36 (see Figure 10) and also serves as a driver housing for the driver 35. The upper protrusion 7i is provided in front of the upper protrusion 7h and protrudes to approximately the same vertical height as the upper protrusion 7h.

[0038] As shown in Figure 3, guide portions 3f and 3g are provided on the upper inner surface of the outer housing 3. Guide portions 3f and 3g are bottomed cylindrical shapes that cover the upper protrusions 7h and 7i from above and the side, respectively. Guide portion 3h is provided on the lower inner surface of the outer housing 3. Guide portion 3h is cylindrical and covers the lower protrusion 7j from the side, and also serves as a support portion for the driver guide. An elastic member 9a is provided as an elastic connecting mechanism 9 between the outer circumferential surface of the upper protrusion 7h and the inner circumferential surface of the guide portion 3f. The elastic member 9a is, for example, a rubber O-ring having an inner diameter approximately the same as the outer diameter of the upper protrusion 7h. Direct contact between the upper protrusion 7h and the guide portion 3f is avoided by using the elastic member 9a.

[0039] As shown in Figure 3, an elastic member 9b is provided as an elastic connecting mechanism 9 between the outer circumferential surface of the upper protrusion 7i and the inner circumferential surface of the guide portion 3g to avoid direct contact between them. The elastic member 9b is, for example, a rubber O-ring having an inner diameter approximately the same as the outer circumferential surface of the upper protrusion 7i. An elastic member 9c is provided as an elastic connecting mechanism 9 between the outer circumferential surface of the lower protrusion 7j and the inner circumferential surface of the guide portion 3h to avoid direct contact between them. The elastic member 9c is, for example, a rubber O-ring having an inner diameter approximately the same as the outer circumferential surface of the lower protrusion 7j. Thus, the hammer housing 7 is held elastically so as not to come into direct contact with the outer housing 3. The motor housing 5 and the gear housing 6 are connected to the hammer housing 7 while avoiding direct contact with the outer housing 3. Therefore, the entire inner housing 4 is held elastically while avoiding direct contact with the outer housing 3.

[0040] Furthermore, the elastic members 9a and 9b also act as cushions to prevent collision between the upper outer surface of the hammer housing 7 and the upper inner surface of the outer housing 3 when the hammer housing 7 compresses the spring 9d with the reaction force during impact and moves upward along the driver movement axis J4. The elastic member 9c also acts as a cushion to prevent collision between the lower outer surface of the hammer housing 7 and the lower inner surface of the outer housing 3 when the compressed spring 9d returns to its initial state by elastic force and biases the hammer housing 7 downward.

[0041] As shown in Figure 10, a coil spring, spring 9d, is inserted into the inner circumferential recess of the upper projection 7h as an elastic connecting mechanism 9. The guide portion 3f on the inner upper surface of the outer housing 3 has a bottom with a closed-end shape. The bottom of the guide portion 3f receives the upper end of the spring 9d as a spring seat 3i. The spring 9d is interposed between the spring seat 3i and the upper projection 7h in the vertical direction on the driver movement axis J4. The spring 9d biases the inner housing 4 downward relative to the outer housing 3. As shown in Figure 14, immediately after the tip 35a of the driver 35 strikes the head of the driving tool N, the inner housing 4 moves upward due to the recoil of the strike. However, because the inner housing 4 is biased downward by the spring 9d, even when it moves upward, it remains at a height that does not contact the inner upper surface of the outer housing 3. Therefore, a state in which the inner housing 4 and the outer housing 3 do not directly contact each other is maintained.

[0042] As shown in Figure 6, the motor 20 is a so-called DC brush motor. The motor shaft 20a of the motor 20 protrudes to the left on the motor rotation axis J1. The motor shaft 20a is rotatably supported by a bearing 20c. The bearing 20c is inserted into and supported by a circular hole 7k provided in the clamping portion 7a of the hammer housing 7. A drive-side spur gear 20b is attached to the left end of the motor shaft 20a. The drive-side spur gear 20b is housed between the motor cap portion 6a and the clamping portion 7a.

[0043] As shown in Figure 6, the intermediate shaft 23 is housed in the gear housing 6 and the hammer housing 7 and extends left and right along the intermediate shaft rotation axis J2. The intermediate shaft 23 is rotatably supported by bearings 23b and 23c. Bearing 23b is inserted and supported within a circular recess 6h provided on the inner surface of the idler gear housing portion 6b of the gear housing 6. Bearing 23c is inserted and supported within a circular recess 7m provided on the inner surface of the idler gear housing portion 7b of the hammer housing 7. An idler gear 23a is mounted at the center of the intermediate shaft 23 in the left-right direction.

[0044] As shown in Figure 6, the spindle 24 is housed in the gear housing 6 and the hammer housing 7 and extends left and right along the hammer rotation axis J3. The spindle 24 is rotatably supported by bearings 24h and 24i. Bearing 24h is inserted into and supported in a circular recess 6i provided on the inner surface of the spindle housing portion 6c of the gear housing 6. Bearing 24i is inserted into and supported in a circular recess 7n provided on the inner surface of the striking mechanism housing portion 7c of the hammer housing 7. A driven spur gear 24a is attached to the left end of the spindle 24. The drive spur gear 20b, the idler gear 23a, and the driven spur gear 24a constitute a single-stage reduction mechanism 21. The drive spur gear 20b and the driven spur gear 24a mesh with the idler gear 23a, respectively. The output of the motor 20 is transmitted from the drive-side spur gear 20b to the driven-side spur gear 24a via the idler gear 23a, while being reduced in speed.

[0045] As shown in Figure 6, a rotating member 31 equipped with a carrier 27 and a hammer 31a is provided on the outer circumference of the center of the spindle 24 in the left-right direction. A planetary reduction mechanism 22 is provided as a reduction mechanism 21 in the power transmission path from the spindle 24 to the rotating member 31. The planetary reduction mechanism 22 has a single-stage planetary gear train. The sun gear 24b of the planetary reduction mechanism 22 is provided on the outer circumference of the spindle 24. An annular internal gear 25 is provided radially outward of the sun gear 24b. The internal gear 25 is supported by the hammer housing 7 by a rib that extends radially outward (see Figure 5) which prevents it from rotating. Three planetary gears 26 are provided radially between the sun gear 24b and the internal gear 25. Each planetary gear 26 rotates on its own axis around a support shaft 26a that extends in the left-right direction and revolves around the sun gear 24b.

[0046] As shown in Figure 6, the three planetary gears 26 are each supported on the disc portion 27a of the carrier 27 via a pivot shaft 26a. The carrier 27 has a cylindrical portion 27b extending to the right from the disc portion 27a. The cylindrical portion 27b has a smaller diameter than the disc portion 27a. A thrust bearing 24j is provided between the left side surface of the disc portion 27a of the carrier 27 and the driven spur gear 24a of the spindle 24 in the left-right direction. The carrier 27 receives the axial force of the spindle 24 via the rotating member 31, but can rotate smoothly on the axis due to its proximity to the thrust bearing 24j.

[0047] As shown in Figure 6, a radial bearing 24k is provided between the outer circumferential surface of the spindle 24 and the inner circumferential surface of the cylindrical portion 27b in the radial direction. The carrier 27 rotates at a slower rotational speed than the spindle 24 by the planetary reduction mechanism 22. By providing the radial bearing 24k, the spindle 24 and the carrier 27 can rotate on the hammer rotation axis J3 while rotating at different rotational speeds from each other.

[0048] As shown in Figure 7, three cam grooves 27c are provided on the outer circumferential surface of the cylindrical portion 27b of the carrier 27. The cam grooves 27c extend inclined axially with respect to the circumferential direction of the cylindrical portion 27b. The cam grooves 27c have a striking position end 27d at the left end and a retracted position end 27e at the right end. A metal ball 32 is interposed between each cam groove 27c and the cam groove 31e of the rotating member 31, which will be described later.

[0049] As shown in Figure 5, the rotating member 31 is cylindrical in shape and extends in the left-right direction. The rotating member 31 has a double structure consisting of an outer cylindrical portion 31b that is radially outward and an inner cylindrical portion 31c that is radially inward. Two hammers 31a are provided so as to protrude radially from the outer cylindrical portion 31b. The two hammers 31a are positioned approximately 180° symmetrically in the circumferential direction. The hollow portion between the outer cylindrical portion 31b and the inner cylindrical portion 31c has a bottom surface 31d at its left end. Three cam grooves 31e are provided on the inner circumferential surface of the inner cylindrical portion 31c. The cam grooves 31e have inclined surfaces that are inclined axially with respect to the circumferential direction of the inner cylindrical portion 31c. The cam grooves 31e have a striking position end 31f at the front end in the rotation direction (counterclockwise in the figure) of the rotating member 31 and a retracted position end 31g at the rear end in the rotation direction.

[0050] As shown in Figure 6, a disc-shaped assist member 24c is attached to the right end of the spindle 24. The assist member 24c is positioned between the bearing 24i and the rotating member 31 in the left-right direction. As shown in Figure 5, three grooves 24f extending radially outward are provided on the inner circumferential surface of the rotating member 31. A ball is interposed between each groove 24f and the spindle 24 as an anti-rotation member 24g. A washer 24m is provided between the right side of the assist member 24c and the bearing 24i to prevent contact between them. As a result, the assist member 24c rotates smoothly on the axis integrally with the spindle 24 at the same rotational speed.

[0051] As shown in Figure 6, multiple balls 24e (see Figure 5) are inserted into a recess on the left side of the assist member 24c. A washer 24d is provided to the left of the assist member 24c to prevent the multiple balls 24e from coming out. A coil spring 33 is provided between the bottom surface 31d of the rotating member 31 and the washer 24d. The spring 33 contacts the bottom surface 31d at its first right end 33a and contacts the washer 24d at its second left end 33b. The spring 33 is conical in shape, with the first end 33a having a larger diameter than the second end 33b. The washer 24d is pressed against the assist member 24c by the biasing force of the spring 33. As a result, the washer 24d rotates axially together with the assist member 24c. The assist member 24c and the washer 24d are allowed to rotate relative to each other to some extent by the interposition of multiple balls 24e.

[0052] As shown in Figures 6 and 8, the rotating member 31 is biased to the left along the hammer rotation axis J3 by a spring 33. The rotating member 31 is movable in the left-right direction relative to the carrier 27 between a left striking position P1 and a right retracted position P2. The hammer 31a strikes the driver 35 at the striking position P1. The hammer 31a does not strike the driver 35 at the retracted position P2. When the rotating member 31 is at the striking position P1, the ball 32 is located between the striking end 27d of the cam groove 27c and the striking end 31f of the cam groove 31e. When the rotating member 31 is at the retracted position P2, the ball 32 is located between the retracted end 27e of the cam groove 27c and the retracted end 31g of the cam groove 31e.

[0053] As shown in Figure 5, the driver 35 extends long in the vertical direction. The driver 35 has a tip 35a at its lower end and a striking portion 35b at its upper end. The tip 35a abuts against the head of the driving tool N (see Figure 10). The striking portion 35b is struck by the hammer 31a. The right side of the striking portion 35b is provided as a planar notch 35c. The notch 35c extends in the vertical and front-rear directions. By providing the notch 35c, it is possible to suppress contact between the driver 35 and the hammer 31a when it rotates on its axis in the retracted position P2 (see Figure 12). A flange 35d that protrudes radially outward is provided at the vertical center of the driver 35. A hole 35e that extends in the front-rear direction substantially perpendicular to the axial direction is provided at the top of the driver 35. A cylindrical anti-rotation pin 36d is inserted through the hole 35e.

[0054] As shown in Figure 5, the driver guide 36 guides the vertical movement of the driver 35. The driver guide 36 includes an upper guide member 36a and a lower guide member 36b. The upper guide member 36a and the lower guide member 36b are each cylindrical and are connected to each other in the vertical direction. A hammer-side opening 36c is provided at the upper end of the upper guide member 36a. The hammer-side opening 36c is inclined downward from rear to front to avoid contact with the hammer 31a.

[0055] As shown in Figure 10, a guide groove 36e extending straight in the vertical direction is provided on the inner rear surface of the upper guide member 36a. A rotation-preventing pin 36d, which protrudes rearward from the driver 35, is inserted into the guide groove 36e. The rotation-preventing pin 36d is slidable in the vertical direction within the guide groove 36e. The engagement of the rotation-preventing pin 36d and the guide groove 36e restricts the axial rotation of the driver 35 and allows it to move vertically relative to the driver guide 36. A coil spring 36f is interposed between the inner upper surface of the upper guide member 36a and the flange 35d of the driver 35 in the vertical direction. The driver 35 is biased downward relative to the driver guide 36 by the spring 36f. This allows the tip 35a of the driver 35 to be in close contact with the driving tool N, enabling efficient striking of the driving tool N.

[0056] As shown in Figure 10, a guide holder 37d is provided below the lower guide member 36b. The guide holder 37d guides the nail guide 37 in the vertical direction. The upper guide member 36a, the lower guide member 36b, and the guide holder 37d are attached to the inner circumference of the lower projection 7j of the hammer housing 7. The nail guide 37 is inserted through the inner circumference of the guide holder 37d. The nail guide 37 is prevented from coming out downward by the lower inner surface of the guide holder 37d. The guide holder 37d and the nail guide 37 also serve as a driver guide that guides the vertical movement of the driver 35. A coil spring, spring 37e, is interposed between the lower surface of the lower guide member 36b and the upper surface of the nail guide 37 in the vertical direction. The nail guide 37 is biased downward relative to the driver guide 36 by the spring 37e. This allows the nailing tool N to be driven into the material W while keeping the opening 37a at the tip of the nail guide 37 in close contact with the material W to be driven.

[0057] As shown in Figure 10, a cylindrical magnet holder 37c is attached to the lower end of the nail guide 37. A magnet 37b is provided on the inner rear surface of the magnet holder 37c. The driving tool N, inserted into the nail guide 37, is held in place by the magnet 37b below the tip 35a of the driver 35 to prevent it from falling out.

[0058] As shown in Figure 15, the switch operating lever 12 has an arm 12b that extends rearward from the switch operating portion 12a. The arm 12b extends from the front surface of the outer housing 3 to the electric switch 13 above the driver 35. The switch operating lever 12 has a box-shaped spring holder 12d that is integrated with the arm 12b behind the switch operating portion 12a. A return spring 12f, which is a coil spring, is housed inside the spring holder 12d. The rear end of the return spring 12f is supported by the inner circumferential surface of the outer housing 3. The return spring 12f biases the switch operating lever 12 forward relative to the outer housing 3. Therefore, when not being pulled by a user, the switch operating portion 12a is initially positioned to protrude forward beyond the curved portion 3d of the outer housing 3.

[0059] As shown in Figure 15, the switch operating lever 12 has a box-shaped spring holder 12e that is integrated with the arm 12b and is located behind the spring holder 12d. A coil spring, which is a buffer spring 12g, and a stepped pin 12h are housed inside the spring holder 12e. The stepped pin 12h protrudes rearward from the rear surface of the spring holder 12e. The stepped pin 12h is prevented from coming out of the spring holder 12e rearward. The buffer spring 12g biases the stepped pin 12h rearward relative to the switch operating lever 12.

[0060] As shown in Figure 15, an electrical switch 13 is provided behind the stepped pin 12h. The electrical switch 13 has a projection 13a that protrudes forward. The electrical switch 13 is in the off state when the projection 13a is not pushed backward. The electrical switch 13 is in the on state when the projection 13a is pushed backward. When the electrical switch 13 is in the on state, it supplies power from the battery 11 to the motor 20 to drive the motor 20 (see Figure 10). The electrical switch 13 is located behind the driver 35.

[0061] As shown in Figure 16, when the user pulls the switch operating part 12a backward, the stepped pin 12h moves backward together with the arm 12b. The stepped pin 12h is biased backward by the buffer spring 12g and contacts the protrusion 13a of the rear electric switch 13. This turns the electric switch 13 on. The length of movement of the protrusion 13a in the front-rear direction is shorter than the amount of movement in the front-rear direction when the switch operating part 12a is pulled. By interposing the buffer spring 12g and the stepped pin 12h between the switch operating lever 12 and the electric switch 13, it is possible to ensure a long operating range for the switch operating part 12a while reliably switching the electric switch 13 on and off.

[0062] As shown in Figure 15, the lock lever 14 has a movement restricting portion 14a that protrudes forward. By sliding the lock lever 14 in the left-right direction, the movement restricting portion 14a moves between a position immediately behind the rear end 12c of the switch operating lever 12 and a position retracted to the left or right relative to the rear end 12c. When the movement restricting portion 14a is positioned immediately behind the rear end 12c and in contact with it, the switch operating portion 12a cannot be pulled backward. Therefore, the electric switch 13 remains in the off state, and the motor 20 (see Figure 10) is not driven. As shown in Figure 16, when the movement restricting portion 14a is retracted to the left or right relative to the rear end 12c, the switch operating portion 12a can be pulled backward. Therefore, the electric switch 13 can be turned on, and the motor 20 can be driven.

[0063] Referring to Figures 6 to 14, the sequence of events in which the driver 35 strikes the nail driver N will be explained. The rotating member 31, equipped with a hammer 31a, is normally positioned at the striking position P1 by the biasing force of the spring 33. As shown in Figure 10, the striking portion 35b of the driver 35 protrudes above the hammer-side opening 36c of the driver guide 36, as it is pushed by the nail driver N held in the nail guide 37. When the lock lever 14 is in the unlocked position, the user can pull the switch operating part 12a backward, and the electric switch 13 turns on. The motor 20 is driven by power supplied from the battery 11. As shown in Figure 6, the driving force of the motor 20 is reduced by the reduction mechanism 21 in the gear housing 6 and transmitted to the spindle 24. Furthermore, the rotational power of the spindle 24 is reduced by the planetary reduction mechanism 22 and transmitted to the carrier 27 and the rotating member 31. As a result, the spindle 24, carrier 27 and rotating member 31 each rotate around the hammer rotation axis J3.

[0064] As shown in Figures 11 and 13, the rotating member 31 at the striking position P1 rotates, causing the hammer 31a to collide with the striking part 35b of the driver 35. The axial rotation of the rotating member 31 is obstructed by the striking part 35b, and the hammer 31a and the striking part 35b engage. The hammer 31a presses the striking part 35b downward and receives a resistive force upward from the striking part 35b. When the resistive force received by the hammer 31a exceeds a predetermined value, the rotating member 31 moves relative to the carrier 27 in the direction opposite to the axial rotation direction. The carrier 27 and the rotating member 31 are connected by the engagement of the balls 32 with the cam grooves 27c and 31e on both sides. As the rotating member 31 rotates relative to the carrier 27, the balls 32 move within the cam grooves 27c and 31e from the striking position ends 27d and 31f to the retracted position ends 27e and 31g. As a result, the rotating member 31 rotates relative to the carrier 27 and moves from the striking position P1 to the retracted position P2 against the biasing force of the spring 33 (see Figures 7 and 9).

[0065] As shown in Figure 12, when the rotating member 31 moves to the retracted position P2, the engagement between the hammer 31a and the part to be struck 35b is released. As a result, the rotating member 31 rotates on its axis without interference. The rotating member 31 is biased from right to left by the spring 33. Therefore, the rotating member 31 attempts to return to the striking position P1 (see Figure 11) while rotating on its axis. As shown in Figures 10 and 13, the ball 32 moves within the cam grooves 27c and 31e from the retracted position ends 27e and 31g to the striking position ends 27d and 31f. The hammer 31a of the rotating member 31, having returned to the striking position P1, collides with the part to be struck 35b again while rotating on its axis. Through the repetition of this series of actions, the hammer 31a repeatedly strikes the driver 35, and the driver 35 repeatedly strikes the head of the driving tool N.

[0066] In the sequence described above, the assist member 24c supporting the second end 33b of the spring 33 rotates at a faster speed than the rotating member 31 supporting the first end 33a of the spring 33. Therefore, when the rotating member 31 rotates axially while being biased by the spring 33 and returning from the retracted position P2 to the striking position P1, the second end 33b of the spring 33 rotates axially around the hammer rotation axis J3 ahead of the first end 33a. As a result, the rotating member 31 rotates axially at a faster speed as if being pulled by the second end 33b of the spring 33. Thus, the impact force exerted by the hammer 31a on the striking part 35b of the driver 35 increases.

[0067] As described above, the striking tool 1 has a spindle 24, a reduction mechanism 21, and a carrier 27, as shown in Figures 6, 8, and 13. The spindle 24 is rotated axially by the motor 20. The reduction mechanism 21 reduces the output from the spindle 24. The carrier 27 is rotated axially by the output of the reduction mechanism 21. The striking tool 1 has a hammer 31a, a spring 33, an assist member 24c, and a driver 35. The hammer 31a is mounted so as to be movable axially and circumferentially relative to the carrier 27. The spring 33 is in contact with the hammer 31a at its first end 33a. The assist member 24c is in contact with the second end 33b of the spring 33 and rotates integrally with the spindle 24. The driver 35 is struck by the hammer 31a. When the hammer 31a returns to its axial position and rotates circumferentially, utilizing the elastic force of the spring 33 which has been elastically deformed by the axial movement of the hammer 31a, the second end 33b of the spring 33 rotates circumferentially in the same direction as the hammer 31a by the assist member 24c, causing the hammer 31a to strike the driver 35.

[0068] Therefore, the assist member 24c rotates axially at the same rotational speed as the spindle 24 upstream of the reduction mechanism 21. As a result, the assist member 24c can be rotated axially at a speed faster than the rotational speed of the carrier 27 and hammer 31a downstream of the reduction mechanism 21. This causes the carrier 27 and hammer 31a to rotate axially in the striking direction, following the second end 33b of the spring 33 held by the assist member 24c. As a result, the rotational speed of the carrier 27 and hammer 31a increases. Thus, the striking force with which the hammer 31a strikes the driver 35 can be increased.

[0069] As shown in Figures 6 and 8, the spindle 24, carrier 27, and spring 33 are arranged coaxially. Therefore, the spindle 24, carrier 27, and spring 33 each rotate around the same axis. This allows the rotational speed of the carrier 27 to be efficiently increased in accordance with the rotation of the spring 33. In addition, the spindle 24, carrier 27, and spring 33 can be arranged compactly. This allows the striking mechanism 30 of the striking tool 1 to be compactly provided in an axially symmetric shape.

[0070] As shown in Figures 6 and 8, the carrier 27 is positioned outside the spindle 24. The sun gear 24b of the planetary reduction mechanism 22, which is the reduction mechanism 21, is provided on the spindle 24. Therefore, by making the reduction mechanism 21 between the spindle 24 and the carrier 27 a planetary reduction mechanism 22, the reduction mechanism 21 and the striking mechanism 30 can be compactly provided in an axisymmetric shape.

[0071] As shown in Figures 6 and 8, a spring 33 is positioned on one axial side of the hammer 31a. A reduction mechanism 21 is positioned on the other axial side of the hammer 31a. Therefore, the reduction mechanism 21 and the striking mechanism 30 can be compactly arranged in the axial direction. Moreover, the hammer 31a and the driver 35 that is struck by the hammer 31a can be positioned in the axial center between the spring 33 and the reduction mechanism 21. As a result, the position where the reaction force is generated when the hammer 31a strikes the driver 35 can be brought closer to the center of gravity of the tool body 2. Thus, when the hammer 31a strikes the driver 35, the tilting of the striking direction of the driver 35 due to the reaction force can be suppressed.

[0072] As shown in Figures 6 and 8, the spindle 24 penetrates the carrier 27 in the axial direction. The spindle 24 has a sun gear 24b on its base end. An assist member 24c is provided on the tip end of the spindle 24. Therefore, the carrier 27 and the spring 33 are arranged coaxially with the spindle 24 and are positioned between the sun gear 24b and the assist member 24c in the axial direction. As a result, a compact assist mechanism can be provided to increase the rotational speed of the carrier 27 and the hammer 31a by following the axial rotation of the spring 33.

[0073] As shown in Figures 5 and 6, the spindle 24 is provided with an anti-rotation member 24g. The anti-rotation member 24g restricts the rotation of the assist member 24c relative to the spindle 24. Therefore, the assist member 24c rotates axially together with the spindle 24. As a result, the assist member 24c can rotate axially at the high rotational speed before deceleration in the reduction mechanism 21. This allows the carrier 27 and hammer 31a to rotate axially more quickly in the striking direction, following the axial rotation of the spring 33.

[0074] As shown in Figures 5 and 6, the spindle 24 is provided with a thrust bearing 24j that supports the carrier 27 so that it can rotate around its axis. Therefore, the carrier 27 can rotate smoothly around its axis at a different rotational speed than the spindle.

[0075] As shown in Figures 5 and 6, a radial bearing 24k is provided between the spindle 24 and the carrier 27 in the radial direction. Therefore, the spindle 24 and the carrier 27 can be stably rotated at different rotational speeds.

[0076] As shown in Figures 5 and 6, the spindle 24, reduction mechanism 21, carrier 27, hammer 31a, and spring 33 are assembled into a single unit. This improves the workability when assembling the striking tool 1.

[0077] As shown in Figure 14, the striking tool 1 has a grip portion 3a. The grip portion 3a is positioned on the opposite side of the driver 35 and on the striking axis J4 in the direction of impact of the driver 35. Therefore, the grip portion 3a held by the operator is positioned on the line of force of the reaction force generated when the hammer 31a strikes the driver 35. This prevents the tool body 2 and the driver 35 from tilting relative to the direction of impact due to the reaction force.

[0078] Next, a second embodiment of this disclosure will be described with reference to Figures 17 to 20. As shown in Figure 17, the driving tool (impact tool) 40 of the second embodiment differs from that of the first embodiment in the arrangement and orientation of the motor. As shown in Figure 18, the driving tool 40 of the second embodiment has an outer housing 41 and an inner housing 42 instead of the outer housing 3 and inner housing 4 (see Figure 3) of the first embodiment. The inner housing 42 houses the motor 47, the reduction mechanism 48, and the impact mechanism 30. The planetary reduction mechanism 22 of the reduction mechanism 48 is the same as that of the first embodiment. In the following description, only the parts that differ from the first embodiment will be described in detail.

[0079] As shown in Figure 17, the outer housing (main housing) 41 has a grip portion 41a, a protrusion 41d, a curved portion 41e, a through hole 41f, and a guide portion 41i, similar to the grip portion 3a, protrusion 3c, curved portion 3d, through hole 3e, and guide portion 3h (see Figure 1). The nail guide 37 protrudes downward from the guide portion 41i. The protrusion 41d is provided with an illumination device 15 that irradiates light toward the area below the opening 37a. The switch operating portion 12a of the switch operating lever 12 protrudes forward from the through hole 41f. When the switch operating portion 12a is not pulled backward, it is located in front of the curved portion 41e. A battery mounting portion 10 is provided on the rear surface of the outer housing 41.

[0080] As shown in Figures 17 and 18, a motor housing accommodating section 41b is provided at the lower rear of the outer housing 41. The motor housing accommodating section 41b is cylindrical in shape, with its axial direction oriented upward from the area below the battery mounting section 10 toward the front. The rear of the motor housing accommodating section 41b bulges toward the rear below the battery mounting section 10. In part, the motor housing accommodating section 41b overlaps with the battery mounting section 10 in the vertical direction. The motor housing accommodating section 41b is located above the protrusion 41d. The motor housing accommodating section 41b covers the motor housing 43, which will be described later, from the outside. Ventilation openings 41c that penetrate from the inside to the outside are provided on the left and right sides of the motor housing accommodating section 41b.

[0081] As shown in Figure 18, the motor rotation axis J1 of the motor 47 extends along the front-rear direction and extends in a direction that is inclined upward toward the front. The intermediate shaft rotation axis J2 of the intermediate shaft 49 (see Figure 19) of the reduction mechanism 48 and the hammer rotation axis J3 of the striking mechanism 30 extend in the left-right direction substantially parallel to each other and are generally positioned on the extension of the motor rotation axis J1 of the motor 47. The driver movement axis (striking axis) J4 on which the driver 35 (see Figure 19) moves extends in the vertical direction substantially perpendicular to the intermediate shaft rotation axis J2 and the hammer rotation axis J3. The intermediate shaft rotation axis J2 is located between the driver movement axis J4 and the motor 47 in the front-rear direction. The hammer rotation axis J3 is located in front of the driver movement axis J4 and above the intermediate shaft rotation axis J2. The intermediate shaft rotation axis J2 is positioned to overlap the striking mechanism 30 in the vertical direction. The hammer rotation axis J3 is positioned to overlap vertically with the battery mounting section 10.

[0082] As shown in Figure 20, the inner housing 42 is provided by integrally assembling the motor housing 43, gear housing 44, and hammer housing 45 with a plurality of fastening members (hex socket head bolts) 46. The motor housing 43, which houses the motor 47, is cylindrical with a bottom surface at the rear and an opening at the front. A ventilation opening 43a is provided on the side of the motor housing 43 that penetrates from the inside to the outside. A plurality of bosses 43b that protrude radially outward are provided on the outer circumferential surface of the front of the motor housing 43. Through holes 43c are provided in the bosses 43b that penetrate in the axial direction of the motor 47.

[0083] As shown in Figure 20, the gear housing 44 has an integrally connected intermediate shaft housing 44a and a spindle housing 44b. The intermediate shaft housing 44a is cylindrical with a bottom on the left side and an opening on the right side. The intermediate shaft housing 44a houses the intermediate shaft 49 and the drive-side spur gear 49b, which will be described later (see Figure 19). The spindle housing 44b is connected to the front part of the intermediate shaft housing 44a. The spindle housing 44b is cylindrical with a bottom on the left side and an opening on the right side. The spindle housing 44b houses the spindle 24 and the left part of the planetary reduction mechanism 22 (see Figure 19). The outer circumferential surface of the gear housing 44 is provided with a plurality of bosses 44c that protrude radially outward. The bosses 44c are cylindrical and extend in the left-right direction. The bosses 44c are provided with through holes 44d that penetrate in the left-right direction.

[0084] As shown in Figure 20, the hammer housing 45 has a motor cap portion 45a, an intermediate shaft housing portion 45b, and a striking mechanism housing portion 45c, which are integrally connected to each other. The motor cap portion 45a is disc-shaped and covers the motor housing 43 from the front. The motor cap portion 45a also serves as the motor housing that houses the motor 47. The intermediate shaft housing portion 45b is provided between the front of the motor cap portion 45a and the rear of the striking mechanism housing portion 45c. As shown in Figure 19, the intermediate shaft housing portion 45b works in cooperation with the intermediate shaft housing portion 44a to house the intermediate shaft 49, the drive-side bevel gear 47b, and the driven-side bevel gear 49a, which will be described later. In other words, the intermediate shaft housing portion 45b also serves as the gear housing.

[0085] As shown in Figure 20, the striking mechanism housing 45c is cylindrical with a bottom on the right side and an opening on the left side. As shown in Figure 19, the striking mechanism housing 45c works in cooperation with the spindle housing 44b to house the right side of the planetary reduction mechanism 22 and the striking mechanism 30. In other words, the spindle housing 44b also serves as the hammer housing.

[0086] As shown in Figure 20, the outer circumferential surface of the motor cap portion 45a is provided with a plurality of bosses 45d that protrude radially outward. The inner circumferential surface of the bosses 45d is provided with female threaded portions 45f that extend in the axial direction of the motor 47. The outer circumferential surface of the striking mechanism housing portion 45c is provided with a plurality of bosses 45e that protrude radially outward. The inner circumferential surface of the bosses 45e is provided with female threaded portions 7g that extend from the left end to the right. A plurality of fastening members 46 are inserted through each through hole 43c of the motor housing 43 and fastened to each female threaded portion 45f of the hammer housing 45. A plurality of fastening members 46 are inserted through each through hole 44d of the gear housing 44 and fastened to each female threaded portion 45g of the hammer housing 45.

[0087] As shown in Figure 19, the motor 47 is a so-called DC brush motor. The motor shaft 47a of the motor 47 protrudes forward on the motor rotation axis J1. The bearing 47c that rotatably supports the motor shaft 47a is inserted into and supported within a hole 43d on the front surface of the motor housing 43. A drive-side bevel gear 47b is attached to the front end of the motor shaft 47a.

[0088] As shown in Figure 19, the intermediate shaft 49 is housed in the gear housing 44 and the hammer housing 45 and extends left and right along the idler gear rotation axis J2. The intermediate shaft 49 is rotatably supported by bearings 49c and 49d. Bearing 49c is inserted and supported in a circular recess 44e provided on the inner surface of the intermediate shaft housing portion 44a of the gear housing 44. Bearing 49d is inserted and supported in a circular recess 45k provided on the inner surface of the intermediate shaft housing portion 45b of the hammer housing 45. A driven bevel gear 49a that meshes with a driven bevel gear 47b is attached to the right side of the intermediate shaft 49. A driven spur gear 49b that meshes with a driven spur gear 24a is attached to the left side of the intermediate shaft 49.

[0089] As shown in Figure 19, the spindle 24 is housed in the gear housing 44 and the hammer housing 45 and extends left and right along the hammer rotation axis J3. The bearing 24h that supports the spindle 24 is inserted into and supported in a circular recess 44f provided on the inner surface of the spindle housing portion 44b of the gear housing 44. The bearing 24i is inserted into and supported in a circular recess 45m provided on the inner surface of the striking mechanism housing portion 45c of the hammer housing 45. A driven spur gear 24a is attached to the left end of the spindle 24. A two-stage reduction mechanism 21 is configured between the drive bevel gear 47b and the driven spur gear 24a of the spindle 24.

[0090] As shown in Figure 18, upper protrusions 45h and 45i are provided on the upper outer surface of the hammer housing 45, similar to the upper protrusions 7h and 7i (see Figure 3) of the first embodiment. A lower protrusion 45j is provided on the lower outer surface of the hammer housing 45, similar to the lower protrusion 7j (see Figure 3) of the first embodiment. The upper protrusion 45h and the lower protrusion 45j are arranged vertically around the driver movement axis J4. The lower protrusion 45j also serves as a driver housing for the driver 35 and driver guide 36. Guides 41g, 41h, and 41i are provided on the outer housing 41, similar to the guides 3f, 3g, and 3h (see Figure 3) of the first embodiment. An elastic member, such as a rubber O-ring, is interposed between the outer circumferential surfaces of the upper protrusions 45h and 45i and the lower protrusion 45j and the inner circumferential surfaces of the guides 41g, 41h, and 41i as an elastic connecting mechanism 9. A coil spring, specifically spring 9d, is inserted into the inner circumferential recess of the upper protrusion 45h as an elastic connecting mechanism 9. A spring seat 41j is provided on the upper surface of the guide portion 41g of the outer housing 41 to receive the upper end of spring 9d. Thus, the entire inner housing 42 is elastically held while avoiding direct contact with the outer housing 41.

[0091] The striking tool 40 of the second embodiment described above provides the same effects as the striking tool 1 of the first embodiment. For example, the striking force with which the hammer 31a strikes the driver 35 can be increased.

[0092] Next, a third embodiment of the present disclosure will be described with reference to Figure 21. The driving tool (impact tool) 60 of the third embodiment has a battery adapter 61 on the rear surface of the outer housing 3 instead of the battery mounting part 10 (see Figure 2) of the first embodiment. The battery adapter 61 is electrically connected to a power source such as a battery 62 located away from the driving tool 60 via a connecting cord 63. Power is supplied from the battery 62 to the motor 20, etc. This impact tool 60 of the third embodiment also provides the same effects as the impact tool 1 of the first embodiment.

[0093] Next, a fourth embodiment of this disclosure will be described with reference to Figure 22. As shown in Figure 22, the driving tool (impact tool) 70 of the fourth embodiment has an outer housing (main housing) 71 instead of the outer housing 3 (see Figure 1) of the first embodiment. In the following description, only the parts that differ from the first embodiment will be described in detail.

[0094] As shown in Figure 22, the outer housing (main housing) 71 has a grip portion 71a, an exposed opening 71b, a curved portion 71d, and a through hole 71e, similar to the grip portion 3a, exposed opening 3b, curved portion 3d, and through hole 3e (see Figure 1). A bulging portion 71c is provided on the upper front surface of the outer housing 71, which bulges forward. The bulging portion 71c is plate-shaped and extends in the front-rear and up-down directions. The bulging portions 71c are provided adjacent to the left and right ends of the switch operating portion 12a in the left-right direction. The upper end of the bulging portion 71c protrudes above the upper end of the switch operating portion 12a. The lower end of the bulging portion 71c protrudes below the lower end of the switch operating portion 12a.

[0095] As shown in Figure 22, the bulge 71c extends forward from the initial state of the switch operating section 12a, which is not pulled backward. Therefore, both the left and right ends of the switch operating section 12a are covered by the bulge 71c. This prevents accidental operation by unintentionally pulling the switch operating section 12a. The striking tool 70 described above provides the same effect as the striking tool 1 of the first embodiment.

[0096] Various modifications can be made to the impact tools 1, 40, 60, and 70 of this embodiment described above. For example, a loose nail gun that drives nails one by one using an impact mechanism has been illustrated. Alternatively, the present disclosure may be applied to other types of impact tools, such as impact drivers, impact wrenches, and hammer drills. A palm-grip type impact tool that is gripped from above the tool body has been illustrated. Alternatively, an impact tool with a grip portion extending from the tool body in a columnar shape or the like may also be used.

[0097] The example given is a striking tool for driving nails. Alternatively, a configuration could be used to drive wooden dowels, iron dowels, or anchor female screws into the material to be driven using a striking mechanism.

[0098] A DC brush motor is used as an example of a power source. Alternatively, a DC brushless motor or similar motor may be used. The number of reduction stages from the motor to the hammer is not limited to the example and can be changed. For example, a planetary reduction mechanism with two or more reduction stages may be used. Alternatively, a configuration without reduction between the motor and the spindle may be used.

[0099] An example is shown of a battery mounting section 10 provided on the rear surface of the outer housing 3, where the battery 11 slides vertically to be attached and detached. Alternatively, the battery may be mounted or detached by sliding horizontally, for example. For example, the battery mounting section may be provided on the top surface or the left and right sides of the outer housing.

[0100] O-rings 9a, 9b, and 9c and a spring 9d are shown as examples of elastic members that elastically hold the inner housing relative to the outer housing. The type, placement, and number of these elastic members are not limited to those shown as examples and may be changed as appropriate. For example, block-shaped rubber members or spring members may be interposed instead of O-rings.

[0101] An example was provided in which the spindle 24 and the assist member 24c are prevented from rotating from each other by the engagement of a ball-shaped anti-rotation member 24g and a groove 24f. Alternatively, for example, the assist member may be screwed to the spindle.

[0102] The outer housing 3 described above exposes a portion of the motor housing 5. Alternatively, the outer housing 3 may cover the entire inner housing 4, including the motor housing 5.

[0103] The motor housing 5, hammer housing 7, and gear housing 6 are fastened together by a fastening member 8. Alternatively, for example, the motor housing 5 and hammer housing 7 may be fastened together, or the hammer housing 7 and gear housing 6 may be fastened together.

[0104] The rotation axis of the idler gear 23a is located closer to the driver guide 36 than the rotation axes of the motor shaft 20a and the hammer 31a. Alternatively, the rotation axis of the idler gear may be further away from the driver guide 36 than the rotation axis of the motor shaft 20a or the hammer 31a.

[0105] The lock lever 14 slides left and right and interferes with the arm 12b of the switch operating section 12a. Alternatively, the lock lever 14 may be configured to tilt left and right and front and back. Or, the lock lever 14 may not be provided at all.

[0106] The front of the outer housing 71 is provided with bulges 71c that protrude forward on both the left and right sides of the switch operating section 12a. The shape and size of the bulges can be changed as appropriate. For example, the foremost end of a bulge may be located in front of the foremost end of the switch operating section 12a.

[0107] The battery adapter 61 of the third embodiment may be applied to, for example, the second embodiment. The bulge 71c of the fourth embodiment may be applied to, for example, the second or third embodiment. [Explanation of Symbols]

[0108] 1… Driving tool (impact tool) 2…Tool body 3...Outer housing (main housing), 3a...Grip section, 3b...Exposed opening 3c...Protrusion, 3d...Curved surface part, 3e...Through hole, 3f, 3g, 3h...Guiding part 3i... Spring seat 4…Inner Housing 5...Motor housing, 5a...Ventilation opening, 5b...Boss, 5c...Female threaded section 6...Gear housing, 6a...Motor cap section, 6b...Idler gear housing section 6c...Spindle housing, 6d, 6e...Boss, 6f, 6g...Through hole, 6h, 6i...Recess 7... Hammer housing, 7a... Clamping section, 7b... Idler gear housing section 7c... Impact mechanism housing, 7d, 7e... Boss, 7f... Through hole, 7g... Female thread section 7h...Top protrusion (spring seat), 7i...Top protrusion, 7j...Bottom protrusion, 7k...Hole 7m, 7n... recessed 8... Fastening member, 8a... Male screw, 8b... Hex socket head bolt 9...Elastic coupling mechanism, 9a, 9b, 9c...Elastic member (O-ring), 9d...Spring 10...Battery mounting section, 10a...Rail, 10b...Connection terminal 11…Battery 12... Switch operating lever, 12a... Switch operating part, 12b... Arm, 12c... Rear end 12d, 12e...spring holder, 12f...return spring, 12g...cushion spring 12h... Stepped pin 13...Electric switch, 13a...Protruding part 14... Lock lever, 14a... Movement restriction section 15…Lighting machine (LED) 20...motor, 20a...motor shaft, 20b...drive-side spur gear, 20c...bearing 21...Reduction mechanism 22... Planetary deceleration mechanism 23...Intermediate shaft, 23a...Idler gear, 23b, 23c...Bearings 24...Spindle, 24a...Driven spur gear, 24b...Sun gear 24c...Assist member, 24d...Washer (spring seat), 24e...Ball, 24f...Groove 24g…Anti-rotation component (ball), 24h, 24i…Bearing, 24j…Thrust bearing 24k...Radial bearing, 24m...Washer 25... Internal gear 26...Planetary gear, 26a...Support shaft 27...Carrier, 27a...Disc part, 27b...Cylindrical part, 27c...Cam groove 27d...end of striking position, 27e...end of retreat position 30... Striking mechanism 31...Rotating member, 31a...Hammer, 31b...Outer cylindrical part, 31c...Inner cylindrical part 31d...Bottom surface (spring seat), 31e...Cam groove, 31f...Striking position end, 31g...Retracted position end 32... Ball 33...spring, 33a...first end, 33b...second end 35...Driver, 35a...Tip, 35b...Area that is struck, 35c...Notch 35d…Flange, 35e…Hole 36...Driver guide, 36a...Upper guide member, 36b...Lower guide member 36c…Hammer side opening, 36d…Anti-rotation pin, 36e…Guide groove, 36f…Spring 37... Nail guide, 37a... Opening, 37b... Magnet, 37c... Magnet holder 37d... Guide holder, 37e... Spring 40… Driving tools (impact tools) 41...Outer housing (main housing), 41a...Grip section 41b…Motor housing section, 41c…Ventilation opening, 41d…Protrusion, 41e…Curved section 41f...Through hole, 41g, 41h, 41i...Guide section, 41j...Spring seat 42...Inner Housing 43...motor housing, 43a...vent, 43b...boss, 43c...through hole, 43d...hole 44...Gear housing, 44a...Intermediate shaft housing, 44b...Spindle housing 44c... Boss, 44d... Through hole, 44e, 44f... Recess 45...Hammer housing, 45a...Motor cap section, 45b...Intermediate shaft housing section 45c... Impact mechanism housing, 45d, 45e... Boss, 45f, 45g... Female thread section 45h…Upper protrusion (spring seat), 45i…Upper protrusion, 45j…Lower protrusion 45k, 45m... recess 46… Fastening component (hex socket head bolt) 47...motor, 47a...motor shaft, 47b...drive-side bevel gear, 47c...bearing 48...Reduction mechanism 49...Intermediate shaft, 49a...Driven bevel gear, 49b...Driven spur gear 49c, 49d... bearings 60… Driving tools (impact tools) 61...Battery adapter 62... Battery 63…Connection cord 70… Driving tools (impact tools) 71...Outer housing (main housing), 71a...Grip section, 71b...Exposed opening 71c...Bulging part, 71d...Curved part, 71e...Through hole J1…Motor rotation axis, J2…Intermediate shaft rotation axis (idler gear rotation axis) J3... Hammer rotation axis, J4... Driver movement axis (impact axis) N... Driving tool (part to be struck) W... material to be driven in P1... Strike position, P2... Evacuation position

Claims

1. It is a striking tool, A spindle that rotates axially by a motor, A reduction mechanism for reducing the output from the spindle, A carrier that rotates on an axis due to the output of the reduction mechanism, A hammer is provided so as to be movable in the axial and circumferential directions relative to the carrier, The aforementioned hammer and a spring that contacts the first end, An assist member that contacts the second end of the spring and rotates integrally with the spindle, The driver is struck by the aforementioned hammer, A striking tool in which, by utilizing the elastic force of the spring that has been elastically deformed by the axial movement of the hammer, the hammer returns to its axial position and rotates in the circumferential direction, and the second end of the spring rotates in the same direction as the hammer by the assist member, causing the hammer to strike the driver.

2. The striking tool according to claim 1, A striking tool in which the spindle, the carrier, and the spring are arranged coaxially.

3. The striking tool according to claim 2, The carrier is positioned outside the spindle, A striking tool in which the sun gear of the planetary reduction mechanism, which is the reduction mechanism, is provided on the spindle.

4. A striking tool according to claim 2 or 3, A striking tool in which the spring is arranged on one axial side of the hammer and the reduction mechanism is arranged on the other axial side.

5. The striking tool according to claim 3, The spindle penetrates the carrier in the axial direction and has the sun gear on its base end. A striking tool in which the assist member is provided on the tip side of the spindle.

6. The striking tool according to claim 5, The striking tool is provided with a spindle that has an anti-rotation member that restricts the rotation of the assist member relative to the spindle.

7. A striking tool according to any one of claims 2 to 6, The striking tool is provided with a thrust bearing on the spindle that supports the carrier so that it can rotate on an axis.

8. A striking tool according to any one of claims 2 to 7, A striking tool in which a radial bearing is provided between the spindle and the carrier in the radial direction.

9. A striking tool according to any one of claims 1 to 8, An impact tool comprising the spindle, the reduction mechanism, the carrier, the hammer, and the spring as an assembly.

10. A striking tool according to any one of claims 1 to 9, A striking tool having a grip portion on the opposite side of the driver and on the axis of the driver in the direction of impact.

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