JP7709855B2 - Dust Collection System - Google Patents

Description

This disclosure relates to a dust collection system in which a dust collection attachment is attached to an impact tool such as a hammer drill.

Impact tools such as hammer drills may be fitted with a dust collection attachment that collects and stores dust generated from the workpiece during drilling and other operations. In a dust collection system consisting of an impact tool and a dust collection attachment, for example, Patent Documents 1 and 2 disclose an invention for mounting the dust collection attachment in which a guide groove is formed in the outer surface of the housing of the impact tool in the vertical direction, and a rail portion that fits into the guide groove is formed in the vertical direction on the dust collection attachment. With this structure, the dust collection attachment can be mounted by sliding it vertically relative to the impact tool.

Patent No. 6726552 Patent No. 6660572

In the above conventional dust collection system, it is desirable to make the rail section long in order to reduce rattling of the dust collection attachment when installed. However, in this case, it becomes necessary to make the guide groove long on the housing side of the impact tool to match the rail section. This requires changing the shape of the housing to ensure the length of the guide groove, which hinders compactness and weight reduction.

The present disclosure therefore aims to provide a dust collection system that can maintain the compactness and light weight of an impact tool, even in a structure in which a dust collection attachment is attached by sliding it in a linear direction relative to the housing of the impact tool.

In order to achieve the above object, the present disclosure provides an impact tool including a housing that accommodates a motor, and a striking mechanism that is provided in the housing and that is capable of striking a tool tip attached to a front end thereof by a striking element that reciprocates;
a dust collection attachment attached to the housing,
The dust collection attachment can be attached by sliding the dust collection attachment vertically relative to the housing such that a pair of left and right convex engaging portions provided on either the housing or the dust collection attachment engage with a pair of left and right concave engaging portions provided on the other of the housing and the dust collection attachment,
the pair of convex-side engaging portions and the pair of concave-side engaging portions are each separated into a plurality of portions in the up-down direction, and include at least a pair of first convex-side engaging portions and a pair of first concave-side engaging portions which engage with each other at an upper side when the dust collection attachment is in an attached state, and a pair of second convex-side engaging portions and a pair of second concave-side engaging portions which engage with each other at a lower side when the dust collection attachment is in an attached state ,
a left-right width of the pair of first convex-side engaging portions and the pair of first concave-side engaging portions that engage with each other on an upper side is smaller than a left-right width of the pair of second convex-side engaging portions and the pair of second concave-side engaging portions that engage with each other on a lower side,
The upper pair of first convex side engaging portions and a pair of first concave side engaging portions, and the lower pair of second convex side engaging portions and a pair of second concave side engaging portions are characterized by having different positions in the front-to-rear direction .

According to the present disclosure, the convex engaging portion and the concave engaging portion are separated in a linear direction, so the dust collection attachment can be attached without rattling even if the convex engaging portion and the concave engaging portion are not formed long. This eliminates the need to change the shape of the housing of the impact tool, making it possible to maintain compactness and light weight.

FIG. 2 is a perspective view of the hammer drill from below. FIG. FIG. FIG. 2 is a central vertical cross-sectional view of the hammer drill. FIG. 5 is an enlarged view of the motor housing portion and the fan accommodating portion of FIG. 4 . 6 is a partial cross-sectional view taken along line AA of FIG. 5. 6 is a partial cross-sectional view taken along line BB of FIG. 5. FIG. 4 is an exploded perspective view of the inside of the fan housing section from above. FIG. 4 is an exploded perspective view of the inside of the fan housing section from below. 6 is a partial cross-sectional view taken along line CC of FIG. 5. FIG. 4 is a rear perspective view of the dust collection attachment. FIG. FIG. FIG. 2 is a central vertical cross-sectional view of the dust collecting attachment. This is a cross-sectional view taken along line D-D in Figure 13. FIG. 4 is an explanatory diagram showing a setting position when the dust collection attachment is attached to the hammer drill (the dust collection attachment and a part of the hammer drill are shown in a central vertical cross section). FIG. 2 is a side view of a mounting portion of the dust collection attachment in the dust collection system. FIG. 2 is a central vertical cross-sectional view of the dust collection system.

In one embodiment of the present disclosure, the first convex engaging portion and the first concave engaging portion, and the second convex engaging portion and the second concave engaging portion may be provided in pairs on the left and right sides, respectively. With this configuration, the dust collection attachment can be attached in a balanced manner, and left-right wobbling of the dust collection attachment in the attached state can be effectively suppressed.
In one embodiment of the present disclosure, the pair of first convex engaging portions and first concave engaging portions and the pair of second convex engaging portions and second concave engaging portions may have different left-right widths, which allows the left-right arrangement of the engaging portions to be matched to the shape of the housing.
In one embodiment of the present disclosure, the linear direction is the up-down direction, and the left-right width of the pair of first convex engaging portion and first concave engaging portion that engage with each other on the upper side may be smaller than the left-right width of the pair of second convex engaging portion and second concave engaging portion that engage with each other on the lower side. This configuration enables the left-right arrangement of the engaging portions to be adapted to the shapes of the housings that differ between the upper and lower sides.
In one embodiment of the present disclosure, the first convex engaging portion and the first concave engaging portion, and the second convex engaging portion and the second concave engaging portion may be positioned differently in the front-rear direction, which allows the engaging portions to be arranged in a front-rear direction in accordance with the shape of the housing.

In one embodiment of the present disclosure, when the dust collection attachment is attached to the housing by sliding it relatively in a linear direction, the first convex engaging portion and the first concave engaging portion and the second convex engaging portion and the second concave engaging portion may be configured so that one of them engages before the other. According to this configuration, the one convex engaging portion and the concave engaging portion that engages first smoothly guides the other convex engaging portion and the concave engaging portion into their respective engaging positions.
In one embodiment of the present disclosure, the first convex engaging portion and the first concave engaging portion, and the second convex engaging portion and the second concave engaging portion may be located on the same line in the linear direction at a predetermined position where the dust collection attachment is abutted against the housing before being slid relatively in the linear direction. With this configuration, the engaging portions can be easily aligned with each other, and the dust collection attachment can be smoothly attached thereafter.
In one embodiment of the present disclosure, one of the housing and the dust collection attachment may be provided with a third convex engaging portion extending in the direction of the impact axis of the impact mechanism, and the other may be provided with a third concave engaging portion that engages with the third convex engaging portion when the dust collection attachment is attached to the housing. With this configuration, left-right wobble of the dust collection attachment is more effectively suppressed, and the unity between the housing and the dust collection attachment is improved.

In one embodiment of the present disclosure, the dust collection attachment has a protrusion that is located on the underside of the housing when attached to the housing 2, and the protrusion may be provided with a hook that engages with the housing when attached. With this configuration, the dust collection attachment is prevented from falling off the housing, and the dust collection attachment is prevented from accidentally shifting or coming off.
In one embodiment of the present disclosure, a dust collection fan may be disposed below the motor, and an air intake port may be provided on the lower surface of the housing to draw in air by rotating the dust collection fan. With this configuration, even if a dust collection fan is provided, it is not necessary to enlarge the motor housing in the radial direction, and compactness can be maintained. In addition, foreign matter such as dust is less likely to enter through the air intake port, and a large opening area can be ensured.
In one embodiment of the present disclosure, a shutter that closes the intake port when the dust collection attachment is not attached may be provided on the underside of the housing, and a pressing member that moves the shutter to an open position of the intake port when the dust collection attachment is attached to the housing may be provided on the protruding portion. With this configuration, the dustproofness and waterproofness of the impact tool can be ensured even when the intake port is provided. In addition, the pressing member can reliably open the shutter when the dust collection attachment is attached.
In one embodiment of the present disclosure, the dust collection attachment may have a slide portion having a suction port at a front end, the slide portion being disposed at a position offset to the left or right from the center in the left-right direction. With this configuration, even with the slide portion, the dust collection attachment can be attached to the front surface of the housing.

Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.
(Hammer drill explanation)
FIG. 1 is a perspective view from below of a hammer drill, which is an example of an impact tool, FIG. 2 is a side view, FIG. 3 is a plan view, and FIG. 4 is a central vertical sectional view of the hammer drill.
The hammer drill 1 includes a housing 2 that forms an outer shell. The housing 2 includes a main housing 3, a rear housing 4, and a front housing 5.
The main housing 3 houses a motor 6 in its lower part, and has a front housing 5 connected to its upper part. The motor 6 is housed with its rotating shaft 7 facing up and down. A pinion 8 is attached to the upper end of the rotating shaft 7 facing upward. The main housing 3 is formed by screwing together left and right half housings 3a, 3b. A number of upper air intakes 3c, 3c... are formed on the top surface of the main housing 3.

The rear housing 4 is equipped with a grip section 9 that extends vertically and is connected to the main housing 3 in a loop shape. The rear housing 4 is formed by screwing together left and right half housings 4a, 4b. A switch 10 with a trigger 11 protruding forward is provided on the upper part of the grip section 9. A battery attachment section 12 is formed on the lower part of the grip section 9. A battery pack 13 is slid into the battery attachment section 12 from the rear. A terminal block 14 that is electrically connected to the battery pack 13 is held within the battery attachment section 12. A controller 15 is housed above the terminal block 14.

The front housing 5 is cylindrical and includes a rear cylinder portion 16 and a front cylinder portion 17. The rear cylinder portion 16 has a generally rectangular cross section extending in the vertical direction, and is screwed from the front to the upper portion of the main housing 3. The front cylinder portion 17 has a circular cross section and protrudes forward from an eccentric position above the rear cylinder portion 16. An operation mode switching knob 18 is provided on the left side surface of the rear cylinder portion 16.
An inner housing 19 is provided at an upper portion inside the main housing 3, and is attached to the rear cylindrical portion 16. A striking mechanism 20 is provided inside the front housing 5 and the inner housing 19.
The impact mechanism 20 has an intermediate shaft 21 and a tool holder 22 arranged in the front-rear direction. The intermediate shaft 21 is rotatably supported inside the front housing 5 and the lower side of the inner housing 19. From the rear, the intermediate shaft 21 is provided with a first gear 23, a boss sleeve 24, a clutch 25, and a second gear 26. The pinion 8 of the rotating shaft 7 penetrates the inner housing 19 from below, is supported by a bearing 27, and is in mesh with the first gear 23.

The tool holder 22 is cylindrical and supported above the intermediate shaft 21 so as to be rotatable coaxially with the front cylindrical portion 17. A third gear 28 is provided in the middle portion of the tool holder 22. The third gear 28 meshes with the second gear 26 of the intermediate shaft 21. The front end of the tool holder 22 protrudes forward from the front cylindrical portion 17. The front end of the tool holder 22 is provided with an operation sleeve 29 to which a bit can be attached and detached.
A piston cylinder 30 is loosely inserted into the rear of the tool holder 22 so as to be movable back and forth. An arm 31 is connected to the rear end of the piston cylinder 30. The arm 31 is mounted on the boss sleeve 24 via a swash bearing whose axis is inclined, and is capable of swinging back and forth. A striker 33 is accommodated inside the piston cylinder 30 via an air chamber 32 so as to be movable back and forth. An impact bolt 34 is provided in front of the piston cylinder 30 and inside the tool holder 22.

A cylindrical motor housing portion 35 is formed below the front housing 5 of the main housing 3. A motor 6 is accommodated in the motor housing portion 35. The motor 6 is a brushless motor including a stator 36 and a rotor 37 having a rotating shaft 7. A lower portion of the rotating shaft 7 passes through a bearing holder 38 formed in the motor housing portion 35 and is supported by a bearing 39. A light 40 that illuminates the area in front of the tool holder 22 is provided on the front surface of the motor housing portion 35, in front of the bearing holder 38.
A pair of left and right chamfered portions 41, 41 are formed on the left and right sides of the motor housing portion 35 from the front to the side. A pair of left and right upper engagement portions 42, 42 are formed on the upper side of the chamfered portions 41, 41. Each upper engagement portion 42 is cut upward from the chamfered portion 41 into the outer surface of the motor housing portion 35, and is groove-shaped with openings on the side and bottom. The lower portion of each upper engagement portion 42 is tapered so that the groove width becomes wider as it goes downward. The upper engagement portions 42, 42 are used for mounting the dust collection attachment 90 described later. An engagement groove 43 extending in the front-rear direction is formed in the center of the left and right of the bottom surface of the rear tube portion 16 above the upper engagement portions 42, 42. The front end of the engagement groove 43 opens forward.

A fan accommodating section 45 is formed below the motor housing section 35. As shown in Fig. 5, the fan accommodating section 45 is formed by an upper plate section 46 and a rear plate section 47 to separate the motor housing section 35 and the battery attachment section 12 within the main housing 3. The upper plate section 46 is a plate extending in the front-rear and left-right directions that divides the inside of the main housing 3 into upper and lower sections. A bearing holder 38 is integrally formed on the upper surface of the upper plate section 46. The rear plate section 47 is a plate extending in the front-rear and left-right directions that extends downward from the rear end of the upper plate section 46 and divides the inside of the main housing 3 into front and rear sections.
The lower end of the rotating shaft 7 penetrates the upper plate portion 46 and protrudes into the fan housing portion 45. A double fan 48 is attached to the lower end of the rotating shaft 7 in the fan housing portion 45 in an orthogonal manner. The double fan 48 is formed with a motor cooling fan 50 on the upper side and a dust collection fan 51 on the lower side, with a partition plate 49 that is circular in plan view as a boundary. Both fans 50, 51 are centrifugal fans. The upper end of each fin 50a of the motor cooling fan 50 is close to the upper plate portion 46. A cover 52 is provided at the lower part of the dust collection fan 51, covering each fin 51a from below, except for the central part. Two ring-shaped upper ribs 53, 53 are formed concentrically downward on the inner peripheral edge and radially outside of the cover 52.
Above the motor cooling fan 50 , upper plate portion 46 is formed with upper ventilation openings 54 , 54 that open to the front and rear of bearing holder 38 in the left-right direction.

6 , the fan accommodating portion 45 is formed to have a larger left-right width than the motor housing portion 35. The front surface of the fan accommodating portion 45 also protrudes further forward than the front surface of the motor housing portion 35. The left-right width of the fan accommodating portion 45 is approximately equal to the left-right width of the battery attachment portion 12 and the battery pack 13.
A pair of left and right lower engagement portions 55, 55 are formed on the left and right side surfaces of the fan housing portion 45 near the front surface. The lower engagement portions 55, 55 are cut upward from the bottom surface of the fan housing portion 45 and are groove-shaped with open sides and bottom. The lower engagement portions 55, 55 are also used for attaching the dust collection attachment 90. The lower engagement portions 55, 55 are parallel to the upper engagement portions 42, 42, but are formed forward and on the left and right outer sides of the upper engagement portions 42, 42.
As shown in Fig. 7, locking grooves 56 extending in the front-rear direction are formed at the lower left and right side surfaces of the fan accommodating section 45, rearward of the lower engagement portions 55. At the rear of the locking grooves 56, protrusions 57 are formed whose left and right rear surfaces protrude toward the inside of the fan accommodating section 45. Slit-shaped side exhaust ports 58 are formed above and below each protrusion 57, connecting the inside of the fan accommodating section 45 to the inside of the locking groove 56. The left and right lower side surfaces of the fan accommodating section 45, on which the locking grooves 56 are formed, have tapered surfaces whose left-right width narrows downward, as shown in Fig. 6.

A baffle plate 60 is provided below the double fans 48 within the fan housing section 45. As shown in Figures 8 and 9, the baffle plate 60 has a generally circular front side and a generally rectangular rear side in plan view. A circular lower air vent 61 is formed in the center of the generally circular part of the baffle plate 60. Two ring-shaped lower ribs 62, 62 are formed concentrically on the inner periphery of the lower air vent 61 and radially outward therefrom, facing upward.
A lower cylinder portion 63 is formed downward on the underside of the baffle plate 60, coaxial with the lower vent 61 and having a larger diameter than the lower vent 61. A locking piece 64 that protrudes forward is formed at the front end of the baffle plate 60. A semi-cylinder portion 65 that rises upward is formed on the left side of the locking piece 64. The semi-cylinder portion 65 is formed with its open side facing radially outward from the baffle plate 60.

A receiving rib 66 for the baffle plate 60 is formed inside the fan housing portion 45. As shown in FIG. 10, the receiving rib 66 is formed above the left and right locking grooves 56, 56 in a manner that surrounds the outer periphery of the rear, left and right, and front right of the baffle plate 60. The left and right sides and the front right side of the receiving rib 66 protrude from the inner surface of the fan housing portion 45. The left side of the receiving rib 66 is connected to a bulging portion 67 that bulges inwardly of the fan housing portion 45 to form the lower engagement portion 55. A plurality of vertical ribs 68, 68... are formed above the bulging portion 67 in the vertical direction. The front right side of the receiving rib 66 is formed to the right side of the locking piece 64 of the baffle plate 60.
The rear portion of the receiving rib 66 is formed at the upper end of a partition wall 69 that is formed by rising upward from the bottom surface of the fan accommodating section 45 forward of the rear plate portion 47. The partition wall 69 divides the interior of the fan accommodating section 45 into front and rear sections below the double fans 48. A bottom exhaust port 70 extending in the left-right direction is formed in the bottom surface of the fan accommodating section 45 behind the partition wall 69.
A groove 71 into which the locking piece 64 is locked is formed on the inner surface of the front part of the fan housing portion 45 .

A circular hole 72 is formed in the bottom surface of the fan housing section 45 in front of the bottom exhaust port 70. The circular hole 72 is formed coaxially with the lower cylinder portion 63 of the baffle plate 60 and has approximately the same diameter as the lower cylinder portion 63. A cap 73 is fitted into the circular hole 72 from the inside. A shutter 74 and a coil spring 75 are interposed between the cap 73 and the baffle plate 60.
The cap 73 has a fitting portion 76 on its underside that fits into the circular hole 72. A circular lower air intake port 77 is formed in the center of the fitting portion 76. The cap 73 has a peripheral wall portion 78 on its outer periphery into which the lower end of the lower tube portion 63 of the baffle plate 60 is inserted and fitted.
The shutter 74 has a disk portion 80 at the center, a ring portion 81 on the outside thereof, and a cross rib 82 connecting the disk portion 80 and the ring portion 81. The disk portion 80 has a larger diameter than the lower air intake port 77 of the cap 73, and a circular protrusion 83 protruding downward is provided at the center of the lower surface. The ring portion 81 has an inner diameter larger than the outer diameter of the disk portion 80 and is arranged concentrically with the disk portion 80. The ring portion 81 has a smaller diameter than the inner diameter of the lower tube portion 63 and can be fitted inside the peripheral wall portion 78 of the cap 73. The cross rib 82 is arranged concentrically on the upper surfaces of the disk portion 80 and the ring portion 81 to connect them. Therefore, four arc-shaped through holes 84, 84... are formed at equal intervals in the circumferential direction between the disk portion 80 and the ring portion 81.
The coil spring 75 is housed in the lower cylinder portion 63. The lower end of the coil spring 75 abuts against the upper surface of the ring portion 81 outside the cross rib 82 of the shutter 74. The upper end of the coil spring 75 abuts against the lower surface of the baffle plate 60.

In the fan housing section 45, the baffle plate 60 holding the shutter 74 and the coil spring 75 and the cap 73 are first assembled between the receiving rib 66 of the left half housing 3a and the bottom surface of the fan housing section 45. At this time, the baffle plate 60 has the semi-cylindrical portion 65 abutting against the vertical ribs 68, 68 on the left bulging portion 67, and the locking piece 64 is engaged with the groove 71. When the right half housing 3b is assembled in this state, the baffle plate 60 is urged by the repulsive force of the coil spring 75 to a position where the left, right and rear portions abut against the receiving rib 66 from below. At the same time, the shutter 74 is urged downward together with the cap 73. Thus, the cap 73 is pressed to a position where the fitting portion 76 fits into the circular hole 72, and the shutter 74 is pressed to a position where the disc portion 80 closes the lower air intake port 77.
In this state, the lower ribs 62, 62 of the baffle plate 60 and the upper ribs 53, 53 of the cover 52 of the dust-collecting fan 51 alternately overlap in the radial direction without contacting each other. Thus, a labyrinth is formed between the dust-collecting fan 51 and the baffle plate 60.
5 and 6, the baffle plate 60 positioned on the receiving rib 66 divides the inside of the fan accommodating section 45 into an upper space A1 and a lower space A2 above the baffle plate 60. The upper space A1 communicates with the rear of the partition wall 69 and the bottom exhaust port 70. The lower space A2 is formed in front of the partition wall 69 and communicates with the left and right side exhaust ports 58, 58. However, a communication port 85 (FIG. 10) is formed between the locking piece 64 and the semi-cylindrical portion 65, which communicates between the upper space A1 and the lower space A2.

In this way, a motor cooling flow path R1 is formed inside the main housing 3 by the rotation of the motor-cooling fan 50 of the double fan 48. In the motor cooling flow path R1, air sucked in from the upper air intake 3c on the top surface of the main housing 3 passes between the main housing 3 and the front housing 5 and the inner housing 19, and through the motor 6, as shown by the dotted arrows in Figure 5. The air then enters the upper space A1 of the fan accommodating section 45 from the upper air vent 54 and is exhausted from the bottom exhaust port 70.
Meanwhile, within the fan housing 45, a main-side dust collection flow path R2 is formed by the rotation of the dust collection fan 51 of the double fan 48. In the main-side dust collection flow path R2, when the shutter 74 rises against the bias of the coil spring 75 and opens the lower air intake 77, air sucked into the lower space A2 from the lower air intake 77 passes through the through hole 84 of the shutter 74, the lower cylinder portion 63 of the baffle plate 60, and the lower air vent 61, enters the upper space A1, and flows from the radial outside of the dust collection fan 51 to the bottom exhaust port 70, as in the motor cooling flow path R1.
However, the motor cooling passage R1 and the main unit dust collection passage R2 each have a branch passage R3. In the branch passage R3, part of the air that has entered the upper space A1 enters the lower space A2 from the radially outer side of the double fan 48 through the communication port 85, passes through the outer periphery of the lower cylinder portion 63 of the baffle plate 60, and is discharged from the side exhaust ports 58, 58, as shown by the two-dot chain arrow in Figure 5.

(Explanation of dust collection attachment)
Fig. 11 is a perspective view showing an example of a dust collection attachment (hereinafter simply referred to as "attachment"), Fig. 12 is a side view of the attachment, Fig. 13 is a plan view, and Fig. 14 is a central vertical cross-sectional view of the attachment.
The attachment 90 includes a casing 91 that is L-shaped in a side view. The casing 91 is formed by assembling left and right half casings 91a, 91b. A main body 92 equipped with a dust box 93 is provided on the front side of the casing 91. A protruding portion 94 that protrudes rearward from the lower portion of the main body 92 is provided on the rear side of the casing 91. A slide portion 95 that protrudes forward is provided on the upper left side of the main body 92.

The casing 91 includes a front top plate 96 that forms the upper surface of the main body 92, a rear top plate 97 that forms the upper surface of the protruding portion 94, a bottom plate 98 that forms the lower surfaces of the main body 92 and the protruding portion 94, a pair of side plates 99, 99 that form the side surfaces of the main body 92 and the protruding portion 94, a front back plate 100 that forms the back surface of the main body 92, and a rear back plate 101 that forms the back surface of the protruding portion 94. The front of the main body 92 is open, and the dust box 93 is detachable from inside the main body 92 from the front.
The sliding portion 95 includes a sliding cylinder 102 and a flexible hose 103. The sliding cylinder 102 is held so as to be movable back and forth by a guide metal fitting 104 provided on the front top plate 96. A nozzle 105 having a suction port 106 is attached perpendicularly to the tip of the sliding cylinder 102. The suction port 106 is located at the center in the left-right direction on the upper side of the main body portion 92.

The flexible hose 103 is loosely inserted into the slide cylinder 102, and its front end is connected to the base end of the nozzle 105. The rear end of the flexible hose 103 is connected to the upstream end of a duct 107 protruding from the left rear part of the main body 92. The flexible hose 103 is provided with a spiral wire integrally therewith and is compressed between the nozzle 105 and the duct 107, urging the slide cylinder 102 forward. The forward and backward positions of the slide cylinder 102 can be regulated by stoppers 108, 108 provided on the side surfaces of the slide cylinder 102.
The downstream end of the duct 107 opens into the main body 92 and communicates with an inlet (not shown) provided in the dust box 93. The dust box 93 includes a cover 109 equipped with a filter 110, and a box body 111 hinged to the cover 109 and covering the filter 110 from the front. The dust box 93 is attached by engaging the lower surface of the box body 111 with a bearing shaft 112 provided at the front end of the bottom plate 98, and by elastically engaging a hook piece 113 protruding forward from the cover 109 with the front end of the front top plate 96. An outlet 114 for air that has passed through the filter 110 is provided at the bottom of the cover 109. A vibration generator 115 is provided at the front of the box body 111. The vibration generator 115 is used to generate vibrations in the box body 111 by rotating it to shake off dust adhering to the filter 110.

The protruding portion 94 is provided with an exhaust tube 116 whose front end is connected to the outlet 114. The exhaust tube 116 is a square tube that extends rearward in the protruding portion 94 and then bends upward. An exhaust port 117 is formed on the upper surface of the rear end of the exhaust tube 116. A rubber cap 118 is placed on the exhaust port 117. The rubber cap 118 has a tapered seal portion 119 at its upper portion, the diameter of which decreases as it goes upward. An opening 120 is formed in the center of the seal portion 119, which is coaxial with and has approximately the same diameter as the exhaust port 117. The rubber cap 118 is fitted into a round hole 121 provided in the rear top plate 97 above the exhaust port 117. The seal portion 119 protrudes upward from the round hole 121. A pin 122 protruding upward is provided in the rear end of the exhaust tube 116 below the exhaust port 117. The pin 122 passes through the exhaust port 117 and the center of the opening 120 in the rubber cap 118 and protrudes upward beyond the rubber cap 118 .
In this way, an attachment-side dust collection flow path R4 is formed in the attachment 90, as indicated by the dashed-dotted arrow in Fig. 14. In the attachment-side dust collection flow path R4, air entering from the suction port 106 passes through the nozzle 105, the flexible hose 103, and the duct 107 into the dust box 93. The air then passes through the filter 110, enters the exhaust pipe 116 from the outlet 114, and is exhausted upward from the exhaust port 117.

The upper surface of the front top plate 96 is formed with a step such that the rear portion is lower than the front portion. The lower surface of the rear tubular portion 16 of the front housing 5 of the hammer drill 1 can be placed on the rear portion of the front top plate 96. An engagement rail 123 is protruded in the front-rear direction from the center in the left-right direction of the rear portion. The engagement rail 123 corresponds to the engagement groove 43 provided on the lower surface of the rear tubular portion 16. The rear edge of the front top plate 96 is curved so that the motor housing portion 35 of the hammer drill 1 fits thereto. The rear upper ends of the left and right side plates 99, 99 connected to the rear edge of the front top plate 96 are a pair of arms 124, 124 whose left-right width is narrower than the front and lower portions of the side plates 99, 99. The left-right width of the arms 124, 124 is slightly larger than the left-right width of the upper portion of the motor housing portion 35. Upper protrusions 125 , 125 that fit into upper engagement portions 42 , 42 provided on the motor housing portion 35 are formed in the vertical direction on the opposing surfaces of the arm portions 124 , 124 .
The left and right widths of the left and right side plates 99, 99 below the upper protrusions 125, 125 are slightly larger than the left and right width of the fan accommodating section 45. Below the upper protrusions 125, 125, lower protrusions 126, 126 that fit into the lower engagement parts 55, 55 provided on the fan accommodating section 45 are formed in the vertical direction on the opposing surfaces of the lower parts of the side plates 99, 99. The lower protrusions 126, 126 are located forward of the upper protrusions 125, 125, similar to the front-to-back positions of the upper engagement parts 42, 42 and the lower engagement parts 55, 55. The front back plate 100 is formed with a plurality of ribs 127, 127... that match the front surfaces of the motor housing section 35 and the fan accommodating section 45 and have curved rear surfaces, spaced apart in the vertical direction and extending in the horizontal direction.

The left and right side plates 99, 99 in the protruding portion 94 protrude upward from the rear top plate 97. A pair of left and right cutouts 130, 130 are formed in the side plates 99, 99 in a vertical band shape. A pair of left and right hook plates 131, 131 are provided in the cutouts 130, 130. As shown in FIG. 15, each hook plate 131 is supported at its upper and lower ends by a support pin 132 installed in the front-rear direction in the cutout 130 so that it can swing left and right. A claw portion 133 that protrudes inward is formed at the upper end of each hook plate 131. The claw portion 133 has a return shape in which the upper surface is inclined downward as it approaches the center of the left and right sides. Each hook plate 131 is rotated in a direction in which the upper end swings inward by a torsion spring 134 held in the protruding portion 94 inside the support pin 132. However, stopper portions 135, 135 (FIGS. 13 and 14) are formed on the front and rear side edges of the notch 130 against which the front and rear side edges of the hook plate 131 abut. Therefore, the hook plates 131, 131 are normally restricted from rotating in a parallel position with the side plates 99, 99, whose upper side edges abut against the stopper portions 135. In this parallel position, the claw portions 133, 133 protrude inward beyond the side plates 99, 99. Finger hook portions 136, 136 are recessed on the outer surfaces of the hook plates 131, 131 below the support pins 132, 132.

(Explanation of the dust collection system)
The attachment 90 is attached to the hammer drill 1. As shown in FIG. 16, the hammer drill 1 and the attachment 90 are first arranged so that the protruding portion 94 is located below the fan housing portion 45 and the arm portions 124, 124 of the side plates 99, 99 are located below the upper engagement portions 42, 42 of the motor housing portion 35. Then, the rib 127 of the front back plate 100 of the attachment 90 is abutted against the front surface of the fan housing portion 45. In this set position, the upper protrusions 125, 125 are located directly below the upper engagement portions 42, 42, and at the same time, the lower protrusions 126, 126 are located directly below the lower engagement portions 55, 55. The engagement rail 123 is located directly below the engagement groove 43. In this state, the rubber cap 118 and the pin 122 of the protruding portion 94 are located directly below the shutter 74 that closes the lower intake port 77.

From this position, the attachment 90 is slid upward, or the hammer drill 1 is slid downward. Then, the upper protrusions 125, 125 that have moved relatively engage with the upper engagement portions 42, 42 from below, and the lower protrusions 126, 126 engage with the lower engagement portions 55, 55 from below. However, due to the difference in upper and lower lengths, the timing of engagement differs between the upper and lower portions, and the lower protrusions 126, 126 engage with the lower engagement portions 55, 55 before the upper protrusions 125, 125 engage with the upper engagement portions 42, 42. Therefore, the upper protrusions 125, 125 are smoothly guided to the engagement position with the upper engagement portions 42, 42 by the lower protrusions 126, 126 that engage first and the lower engagement portions 55, 55. Even if there is some rattling, the upper projections 125, 125 are reliably guided into the upper engagement portions 42, 42 by the tapered shape of the lower portions of the upper engagement portions 42, 42. Meanwhile, as the attachment 90 moves relative to the engagement portion 42, the engagement rail 123 also engages with the engagement groove 43 from below.
When the upper protrusion 125 abuts against the upper surface of the upper engagement portion 42, the lower protrusion 126 abuts against the upper surface of the lower engagement portion 55, and the engagement rail 123 abuts against the lower surface of the front housing 5, the relative movement of the attachment 90 is restricted.

During this relative movement of the attachment 90, the claws 133, 133 of the hook plates 131, 131 of the protruding portion 94 abut against the inclination of the lower side surface of the fan housing portion 45, and the upper ends of the hook plates 131, 131 spread out to the left and right against the bias of the torsion springs 134, 134. This allows the attachment 90 to move relative to the fan housing portion 45. When the relative movement of the attachment 90 is restricted by the abutment of the engaging portions, the claws 133, 133 simultaneously reach the locking grooves 56, 56. Then, the hook plates 131, 131 are returned to a parallel position by the bias of the torsion springs 134, 134. Therefore, as shown in FIG. 17, the engaging portions engage with each other and the claws 133, 133 are locked in the locking grooves 56, 56.
Meanwhile, with the relative movement of the attachment 90, the pin 122 abutting against the circular protrusion 83 of the shutter 74 pushes up the shutter 74 against the bias of the coil spring 75. Thus, as shown in Figure 18, the lower air intake port 77 opens, and the seal portion 119 of the rubber cap 118 abuts against the lower surface of the cap 73 and elastically deforms, sealing the gap between the lower air intake port 77 and the exhaust port 117.

In this manner, the dust collection system S is obtained in which the attachment 90 is mounted in a state in which its movement in the up-down and front-rear and left-right directions is restricted with respect to the hammer drill 1. In this state, the attachment-side dust collection passage R4 communicates with the main machine-side dust collection passage R2.
When forming this dust collection system S, the attachment 90 in the set position in Fig. 16 may be moved relatively to the mounting position in Figs. 17 and 18. Therefore, the stroke of the relative movement of the attachment 90 during mounting can be short. Also, in the set position in Fig. 16 where the rib 127 of the front back plate 100 of the casing 91 abuts from the front against the front surfaces of the motor housing section 35 and the fan accommodating section 45, the upper engagement section 42 and the upper protrusion 125, the lower engagement section 55 and the lower protrusion 126, and the engagement groove 43 and the engagement rail 123 are positioned in the same vertical line. Therefore, the respective engagement sections can be easily aligned, and the attachment 90 can be smoothly mounted thereafter.

In the dust collection system S, the suction port 106 of the attachment 90 is pressed against the surface of the workpiece to be processed, and the tip of the bit B (FIG. 18) is set in the suction port 106. In this state, the trigger 11 of the hammer drill 1 is pressed. Then, the switch 10 is turned on, and the controller 15 drives the motor 6. Thus, the rotating shaft 7 and the intermediate shaft 21 rotate via the pinion 8. At this time, the clutch 25 is slid by operating the switching knob 18 provided on the side of the front housing 5. Then, it is possible to select one of the forward position (drill mode) in which the clutch 25 engages only with the second gear 26, the backward position (hammer mode) in which the clutch 25 engages only with the boss sleeve 24, and the intermediate position (hammer drill mode) in which the clutch 25 engages simultaneously with the second gear 26 and the boss sleeve 24. In the drill mode, the tool holder 22 rotates via the third gear 28 to rotate the bit B. In the hammer mode, the piston cylinder 30 reciprocates due to the swinging of the arm 31. This causes the striker 33 to reciprocate in conjunction with the arm 31 via the air chamber 32. The striker 33 then strikes the bit B via the impact bolt 34. In the hammer drill mode, the tool holder 22 rotates and the impact bolt 34 strikes simultaneously.

When the hammer drill 1 is advanced with the suction port 106 set, the slide cylinder 102 retracts together with the nozzle 105, and the bit B penetrates the suction port 106, making it possible to process the workpiece.
The double fan 48 rotates simultaneously with the rotation of the rotary shaft 7. Thus, the rotation of the motor-cooling fan 50 causes air to flow through the motor-cooling flow passage R1. That is, air drawn in from the upper air intake 3c passes through the main housing 3, the front housing 5, and the motor 6 in that order, cooling each of them. The cooled air then enters the upper space A1 of the fan housing portion 45 from the upper air vent 54 and is exhausted from the bottom exhaust port 70.

Meanwhile, the rotation of the dust collection fan 51 causes air to flow in the attachment-side dust collection flow path R4 and the main-machine-side dust collection flow path R2. That is, air sucked in from the suction port 106 where suction force is generated flows in the order of the flexible hose 103, the duct 107, the dust box 93, and the exhaust pipe 116, and then passes through the lower intake port 77, the lower vent 61 of the baffle plate 60, enters the upper space A1, and is discharged from the bottom exhaust port 70. At the same time, part of the air that has entered the upper space A1 flows into the branch flow path R3. That is, part of the air enters the lower space A2 through the communication port 85, and is discharged from the side exhaust ports 58, 58.
Therefore, dust generated from the workpiece is sucked into the suction port 106 and enters the dust box 93 via the nozzle 105, flexible hose 103, and duct 107, and is captured by the filter 110 and stored in the box body 111.

When removing the attachment 90, the finger hooks 136, 136 of the left and right hook plates 131, 131 of the protrusion 94 are pinched and pushed inward. Then, the hook plates 131, 131 change from a parallel posture to an open posture in which the upper ends are opened outward to the left and right, and the claws 133, 133 are separated from the locking grooves 56, 56. Therefore, if the attachment 90 is slid downward or the hammer drill 1 is slid upward, the upper protrusion 125 and the lower protrusion 126 are respectively disengaged downward from the upper engagement portion 42 and the lower engagement portion 55 as shown in FIG. 16. At the same time, the engagement rail 123 is disengaged downward from the engagement groove 43 and reaches a set position. Therefore, if the attachment 90 is moved forward relative to the hammer drill 1, it can be separated from the hammer drill 1. In this way, the attachment 90 only needs to be relatively moved from the mounting position shown in FIGS. 17 and 18 to the set position shown in FIG. 16, and therefore the stroke of the relative movement of the attachment 90 when detaching it can be short.
The dust stored in the box body 111 of the dust box 93 can be disposed of by removing the dust box 93 from the attachment 90 and opening the lid 109 .

(Effects of disclosure regarding hammer drills)
The hammer drill 1 of the above embodiment includes a housing 2 to which an attachment 90 can be attached, and an impact mechanism 20 that is provided within the housing 2 and is capable of striking a bit B (tool tip) attached to the front end with a striker 33 (impactor) that reciprocates. The hammer drill 1 also includes a motor 6 that is disposed within the housing 2 such that a rotation shaft 7 intersects with the impact axis direction of the impact mechanism 20, and a dust collection fan 51 that is provided on the rotation shaft 7. The dust collection fan 51 is disposed below the motor 6.
With this configuration, it is not necessary to increase the radial size of the motor housing portion 35 (motor housing) in accordance with the outer diameter of the dust collection fan 51. Therefore, even if the dust collection fan 51 is provided, the hammer drill 1 can be kept compact.

In particular, the rotating shaft 7 is provided with a motor cooling fan 50 adjacent to the dust collection fan 51 in the axial direction of the rotating shaft 7. Therefore, even if the motor cooling fan 50 is provided in addition to the dust collection fan 51, it is not necessary to increase the radial size of the motor housing portion 35 (the portion that accommodates the motor), and the compact size can be maintained.
A lower air intake 77 (air intake) that draws in air by the rotation of the dust collection fan 51 is provided on the lower surface of the housing 2. This makes it difficult for foreign matter such as dust to enter through the lower air intake 77, and also ensures a wide opening area.
A bottom exhaust port 70 (exhaust port) that exhausts air by rotation of the dust collection fan 51 is provided on the bottom surface of the housing 2. This makes it difficult for foreign matter such as dust to enter through the bottom exhaust port 70, and also ensures a wide opening area.
A side exhaust port 58 (second exhaust port) for discharging air by rotation of the dust collection fan 51 is provided on the side surface of the housing 2. Therefore, a necessary amount of air can be secured.

The lower air intake 77 can be opened and closed by a disk-shaped shutter 74. Therefore, even if the lower air intake 77 is provided, the dustproof and waterproof properties of the hammer drill 1 can be ensured.
The shutter 74 is disposed coaxially with the dust collection fan 51. This allows the shutter 74 to be disposed compactly. In addition, the air flows smoothly when the shutter 74 is open.
The left-right width of the fan housing portion 45 (the housing portion for housing the dust-collection fan) in the housing 2 is greater than that of the motor housing portion 35 in the housing 2. Therefore, the motor housing portion 35 becomes slimmer and has a better appearance.
The bearing 39 that supports the rotary shaft 7 inside the housing 2 is disposed above the dust collection fan 51. Therefore, the motor housing portion 35, including the bearing 39 portion, can be kept compact.

The attachment 90 can be attached by sliding it vertically (in a predetermined linear direction) relative to the housing 2, whereby the upper engagement portion 42 and the lower engagement portion 55 provided on the housing 2 engage with the upper protrusion 125 and the lower protrusion 126 provided on the attachment 90. The upper engagement portion 42 and the lower engagement portion 55 provided on the housing 2 are separated in the vertical direction.
Therefore, the attachment 90 can be attached without rattling even if the upper engagement portion 42 and the lower engagement portion 55 are not formed long. This eliminates the need to change the shape of the housing 2, making it possible to maintain compactness and light weight.

(Example of modification of disclosure related to hammer drill)
The shape and size of the dust collection fan are not limited to those in the above embodiment. For example, a dust collection fan without a cover on the bottom surface can be used. Fans other than centrifugal fans can also be used.
In the above embodiment, a double fan is used in which the motor cooling fan is adjacent to the dust collection fan, but instead of using a double fan, only the dust collection fan may be provided below the motor.
The motor may be disposed in any manner so long as the rotation shaft intersects with the striking axis direction, and is not limited to the orthogonal arrangement as in the above embodiment.
The position and shape of the intake port are not limited to the lower intake port of the above embodiment. The shape of the shutter can also be changed as appropriate. The shutter does not have to move up and down to open and close the intake port as in the above embodiment, but may have a structure in which, for example, a part of the shutter is connected to the fan housing part by a hinge or the like, and the shutter rotates around an axis to open and close the intake port. The shutter may also have a structure in which the shutter moves linearly in a direction intersecting the intake port to open and close the intake port.
The intake port and the exhaust port can be provided on a surface other than the bottom surface of the housing, and the position and shape of the cap and the shutter can be changed to match the position of the intake port.
It is also possible to eliminate the communication port between the upper and lower spaces in the fan housing, i.e., to eliminate the branch flow passage and omit the side exhaust port.
The configuration of the dust collection passage on the main unit side inside the fan housing can also be changed as appropriate. Air may be sent to the battery mounting section side to be used for cooling the controller.

In the present disclosure, the engagement portion for the attachment provided on the impact tool is not limited to the structure in which the engagement portion is separated in the vertical direction like the upper engagement portion and the lower engagement portion in the above embodiment. That is, the attachment may be attached by engaging one or a pair of convex engagement portions and one or a pair of concave engagement portions extending in the vertical direction with each other.
In the above embodiment, the attachment is detachable by moving it vertically relative to the hammer drill, but it may be detachable by moving it forwards and backwards or left and right.
However, the mounting structure of the attachment to the housing in the present disclosure is not limited to the engagement of engaging parts by linear movement as in the above embodiment, and may be modified as appropriate, for example, to have an engaging and disengaging structure between an engaging part such as a hook and a receiving part such as a recess.
The configuration of the impact mechanism is not limited to the above embodiment, and a motor other than a brushless motor may be used.
The present disclosure is not limited to a hammer drill, but may be applied to other impact tools such as an electric hammer, etc. An AC tool may be used instead of a DC tool.

(Effects of disclosure regarding dust collection systems)
In the dust collection system S, the attachment 90 can be attached by sliding it relatively in the vertical direction (a predetermined linear direction) with respect to the housing 2 of the hammer drill 1, so that the upper engagement portion 42 and the lower engagement portion 55 (concave-side engagement portion) provided on the housing 2 engage with the upper protrusion 125 and the lower protrusion 126 (convex-side engagement portion) provided on the attachment 90. The convex-side engagement portion and the concave-side engagement portion are each separated in the vertical direction, and include the upper engagement portion 42 (first concave-side engagement portion) and the upper protrusion 125 (first convex-side engagement portion) which engage with each other when the attachment 90 is attached, and the lower engagement portion 55 (second concave-side engagement portion) and the lower protrusion 126 (second convex-side engagement portion) which engage with each other in the attached state.
According to this configuration, the attachment 90 can be attached without rattling even if the upper engagement portion 42 and the lower engagement portion 55 are not formed long. This eliminates the need to change the shape of the housing 2, making it possible to maintain compactness and light weight.

In particular, the upper engagement portion 42 and the upper protrusion 125, and the lower engagement portion 55 and the lower protrusion 126 are provided in pairs on the left and right sides, respectively. This allows the attachment 90 to be attached in a well-balanced manner, and effectively prevents the attachment 90 from wobbling in the left-right direction when attached.
The pair of upper engagement portions 42 and the upper protrusions 125 and the pair of lower engagement portions 55 and the lower protrusions 126 have mutually different left and right widths. This allows the left and right arrangement of the engagement portions to match the shape of the housing 2.
The linear direction is the up-down direction, and the left-right width of the pair of upper engagement portions 42 and upper protrusions 125 that engage with each other at the top is smaller than the left-right width of the pair of lower engagement portions 55 and lower protrusions 126 that engage with each other at the bottom. This makes it possible to arrange the engagement portions on the left and right to match the shapes of the housing 2 that differ above and below, such as the motor housing portion 35 and the fan accommodating portion 45. In addition, because the left-right width of the lower engagement portions is large, the connection state between the fan accommodating portion 45 and the protrusion 94 is stable.
The upper engagement portion 42 and the upper protrusion 125, and the lower engagement portion 55 and the lower protrusion 126 are located at different positions in the front-rear direction. This allows the engagement portions to be arranged in a front-rear direction in accordance with the shape of the housing 2.

When the attachment 90 is attached to the housing 2 by sliding it relatively in the up-down direction, the lower engagement portion 55 and the lower protrusion 126 engage before the upper engagement portion 42 and the upper protrusion 125. Therefore, the lower protrusion 126 is smoothly guided to the engagement position with the lower engagement portion 55 by the lower engagement portion 55 and the lower protrusion 126, which engage first.
At a predetermined position where the attachment 90 is in contact with the housing 2 before being slid relatively up and down, the upper engagement portion 42 and the upper protrusion 125, and the lower engagement portion 55 and the lower protrusion 126 are each positioned on the same line in the up and down direction. This makes it easy to align the engagement portions with each other, and allows the attachment 90 to be installed smoothly thereafter.
The housing 2 is provided with an engagement groove 43 (third concave engagement portion) extending in the direction of the impact axis of the impact mechanism 20, and the attachment 90 is provided with an engagement rail 123 (third convex engagement portion) that engages with the engagement groove 43 when the attachment 90 is attached to the housing 2. This more effectively prevents the attachment 90 from wobbling in the left-right direction, improving the unity between the housing 2 and the attachment 90.

The attachment 90 has a protruding portion 94 that is located on the underside of the housing 2 when attached to the housing 2, and a hook plate 131 (hook portion) that engages with the housing 2 when attached is provided on the protruding portion 94. This prevents the attachment 90 from falling off the housing 2, and prevents the attachment 90 from accidentally shifting or coming off.
The dust collection fan 51 is disposed below the motor 6, and a lower air intake 77 is provided on the lower surface of the housing 2, through which air is drawn in by the rotation of the dust collection fan 51. Therefore, even if the dust collection fan 51 is provided, it is not necessary to enlarge the motor housing part 35 in the radial direction, and the compact size can be maintained. In addition, foreign matter such as dust is less likely to enter through the lower air intake 77, and a large opening area can be secured.

A shutter 74 that closes the lower air intake port 77 when the attachment 90 is not attached is provided on the underside of the housing 2, and a pin 122 (pressing member) that moves the shutter 74 to a position that opens the lower air intake port 77 when the attachment 90 is attached to the housing 2 is provided on the protruding portion 94. This ensures that the hammer drill 1 is dustproof and waterproof even when the lower air intake port 77 is provided. In addition, the shutter 74 can be reliably opened by the pin 122 at the same time as the attachment 90 is attached.
The attachment 90 has a slide portion 95 having a suction port 106 at its front end, which is disposed at a position offset to the left from the center in the left-right direction. Therefore, even with the slide portion 95, the attachment 90 can be attached to the front surface of the housing 2.

(Example of modification of disclosure related to dust collection system)
In the above embodiment, the groove-shaped concave engaging portion is formed on the housing side of the hammer drill and the ridge-shaped convex engaging portion is formed on the attachment side, but this may be reversed. That is, the ridge-shaped convex engaging portion may be formed on the housing side and the groove-shaped concave engaging portion may be formed on the housing side. The housing and the attachment may each be provided with a mixture of convex and concave engaging portions.
In the above embodiment, the lower engaging portions engage with each other before the upper engaging portions engage with each other, but this may be reversed. Also, the separated engaging portions may be engaged with each other at the same time.
The convex engaging portion and the concave engaging portion are not limited to a pair. For example, if the convex engaging portion and the concave engaging portion are engaged in a dovetail shape, attachment and detachment are possible even if there is only one convex engaging portion and one concave engaging portion.
The engaging groove and the engaging rail can be modified in the same manner. That is, the engaging rail may be formed on the housing side and the engaging groove on the attachment side. However, the engaging groove and the engaging rail may be omitted.
In the above embodiment, the convex engaging portion and the concave engaging portion are separated into two locations in the vertical direction.
The left-right width and the front-rear positional relationship of the convex engaging portion and the concave engaging portion may also be changed as appropriate. Therefore, the left-right width and the front-rear positional relationship of the convex engaging portion and the concave engaging portion may be the same.

In the above embodiment, the attachment is detachable by moving it vertically relative to the hammer drill, but the present disclosure can also be used if the attachment is detachable by moving it forwards/backwards or left/right. Therefore, the convex engaging portion and the concave engaging portion can be oriented in different directions depending on the linear direction in which the attachment is attached or detached.
In the attachment, the position of the slide part may be reversed. If the attachment can be easily attached, the slide part may be located in the center in the left-right direction. The structure of the dust box may also be modified as appropriate. The dust collection passages may be connected between the front surface of the housing of the impact tool and the rear surface of the casing of the attachment without providing a protruding part.
In the above embodiment, the dust collection fan is provided in the hammer drill, and air flows in the dust collection passage on the attachment side when the attachment is attached, but the present disclosure is not limited to this structure. For example, the attachment structure of the engaging parts of the present disclosure can be adopted even in a structure in which a motor and a dust collection fan are provided in the casing of the attachment, and the motor and the dust collection fan are rotated by receiving power from the impact tool when the attachment is attached to the impact tool.
The configuration of the impact mechanism is not limited to the above embodiment. A motor other than a brushless motor can be used. The direction of the motor can also be changed, and the dust collection fan can be located above the motor.
The dust collection system of the present disclosure is not limited to a hammer drill, but may be used with other impact tools such as an electric hammer, etc. An AC tool may be used instead of a DC tool.

1: hammer drill, 2: housing, 3: main housing, 3c: upper air intake, 4: rear housing, 5: front housing, 6: motor, 7: rotating shaft, 16: rear cylinder, 17: front cylinder, 20: striking mechanism, 21: intermediate shaft, 22: tool holder, 27, 39: bearing, 35: motor housing, 38: bearing holder, 42: upper engagement portion, 43: engagement groove, 45: fan housing, 46: upper plate, 47: rear plate, 48: double fan, 50: motor cooling fan, 51: dust collection fan, 54: upper air vent, 55: lower engagement portion, 58: side exhaust port, 60: baffle plate, 69: partition wall, 70:・Bottom exhaust port, 73: Cap, 74: Shutter, 75: Coil spring, 77: Lower intake port, 90: Dust collection attachment, 91: Casing, 92: Main body, 93: Dust box, 94: Protrusion, 95: Slide, 106: Intake port, 110: Filter, 117: Exhaust port, 118: Rubber cap, 122: Pin, 123: Engagement rail, 124: Arm, 125: Upper ridge, 126: Lower ridge, 131: Hook plate, B: Bit, R1: Motor cooling passage, R2: Main unit dust collection passage, R3: Branch passage, R4: Attachment dust collection passage, A1: Upper space, A2: Lower space, S: Dust collection system.

Claims (8)

an impact tool including a housing that accommodates a motor, and a striking mechanism that is provided in the housing and that can strike a tool tip attached to a front end thereof with a striking element that reciprocates;
a dust collection attachment attached to the housing,
The dust collection attachment can be attached by sliding the dust collection attachment vertically relative to the housing such that a pair of left and right convex engaging portions provided on either the housing or the dust collection attachment engage with a pair of left and right concave engaging portions provided on the other of the housing and the dust collection attachment,
the pair of convex-side engaging portions and the pair of concave-side engaging portions are each separated into a plurality of portions in the up-down direction, and include at least a pair of first convex-side engaging portions and a pair of first concave-side engaging portions which engage with each other at an upper side when the dust collection attachment is in an attached state, and a pair of second convex-side engaging portions and a pair of second concave-side engaging portions which engage with each other at a lower side when the dust collection attachment is in an attached state ,
a left-right width of the pair of first convex-side engaging portions and the pair of first concave-side engaging portions that engage with each other on an upper side is smaller than a left-right width of the pair of second convex-side engaging portions and the pair of second concave-side engaging portions that engage with each other on a lower side,
A dust collection system in which the upper pair of first convex side engaging portions and the pair of first concave side engaging portions, and the lower pair of second convex side engaging portions and the pair of second concave side engaging portions are positioned differently in the front-to-rear direction . 2. The dust collection system of claim 1, wherein when the dust collection attachment is attached to the housing by sliding it relatively in the vertical direction, one of the upper pair of first convex side engaging portions and the pair of first concave side engaging portions and the lower pair of second convex side engaging portions and the pair of second concave side engaging portions engages before the other. 3. The dust collection system according to claim 1 or 2, wherein, when the dust collection attachment is abutted against the housing before being slid relatively in the vertical direction, the upper pair of first convex side engaging portions and the pair of first concave side engaging portions, and the lower pair of second convex side engaging portions and the pair of second concave side engaging portions are each positioned on the same line in the vertical direction. A dust collection system as described in any one of claims 1 to 3, wherein one of the housing and the dust collection attachment is provided with a third convex side engaging portion extending in the impact axis direction of the impact mechanism portion, and the other is provided with a third concave side engaging portion that engages with the third convex side engaging portion when the dust collection attachment is attached to the housing. 5. A dust collection system as described in any one of claims 1 to 4, wherein the dust collection attachment has a protrusion located on the underside of the housing when attached to the housing, and the protrusion is provided with a hook portion that engages with the housing in the attached state. 6. The dust collection system according to claim 5 , wherein a dust collection fan is disposed below the motor, and an air intake port is provided on the bottom surface of the housing for sucking in air by rotation of the dust collection fan. 7. The dust collection system according to claim 6, wherein a shutter that closes the air intake port when the dust collection attachment is not attached is provided on the underside of the housing, and a pressing member that moves the shutter to a position that opens the air intake port when the dust collection attachment is attached to the housing is provided on the protrusion . 8. The dust collection system according to claim 1 , wherein the dust collection attachment has a slide portion having a suction port at a front end, the slide portion being disposed at a position offset to the left or right from a center in the left-right direction.