Impact tool and dust collection system

1. An impact tool comprising:

a housing configured to mount a dust collection attachment;

an impact mechanism unit (i) inside the housing, (ii) having (a) a front end configured to receive and retain a tool bit and (b) an impact element that reciprocates, and (iii) being configured to impact the tool bit by the impact element when the tool bit is retained by the front end;

a motor having a rotation shaft that intersects an impact axis direction of the impact mechanism unit inside the housing;

a dust collection fan on the rotation shaft; and

a motor cooling fan (i) on the rotation shaft and (ii) adjacent to the dust collection fan in an axial direction of the rotation shaft; wherein

the motor cooling fan is integrally formed on an upper side of the dust collection fan with a partition plate having a circular shape in plan view as a boundary,

only the partition plate is between the motor cooling fan and the dust collection fan in the axial direction,

the dust collection fan is below the motor, and

the motor cooling fan and the dust collection fan are on a same side of the motor in the axial direction.

2. The impact tool according to claim 1 , wherein

the dust collection fan and the motor cooling fan are centrifugal fans.

3. The impact tool according to claim 1 , further comprising

an air inlet (i) on a lower surface of the housing and (ii) suctioning air from outside the housing when the dust collection fan rotates.

4. The impact tool according to claim 3 , further comprising

an exhaust outlet (i) on the lower surface of the housing and (ii) discharging the air when the dust collection fan rotates.

5. The impact tool according to claim 4 , further comprising

a baffle plate that forms a labyrinth in close proximity to the dust collection fan and is configured to cause the air inlet to communicate with the exhaust outlet via the dust collection fan below the dust collection fan.

6. The impact tool according to claim 5 , further comprising

a disk-shaped shutter configured to open or close the air inlet.

7. The impact tool according to claim 6 , wherein

the shutter is coaxial with the dust collection fan.

8. The impact tool according to claim 7 , further comprising

a coil spring between the baffle plate and the shutter, wherein

the coil spring is configured to position the baffle plate at a position close to the dust collection fan when the shutter is positioned at a position where the air inlet is closed.

9. The impact tool according to claim 4 , further comprising

a second exhaust outlet (i) on a side surface of the and (ii) discharging the air when the dust collection fan rotates.

10. The impact tool according to claim 9 , wherein

the side surface of the housing has a locking groove where the dust collection attachment is locked to the housing in a mounted state,

the locking groove projects into a housing portion of the dust collection fan, and

the second exhaust outlet has a slit shape in an up-down direction of a projection portion of the locking groove.

11. The impact tool according to claim 1 , wherein

a housing portion of the dust collection fan in the housing has a right-left width larger than a right-left width of a housing portion of the motor in the housing.

12. The impact tool according to claim 1 , further comprising

a bearing (i) above the dust collection fan and (ii) supporting the rotation shaft inside the housing.

13. The impact tool according to claim 12 , further comprising

a plate portion (i) between a housing portion of the dust collection fan and a housing portion of the motor and (ii) partitioning the housing portion of the dust collection fan in the housing,

wherein the bearing is held on an upper surface of the plate portion.

14. The impact tool according to claim 1 , wherein

the dust collection attachment is configured to be mounted to the housing such that a projecting side engaging portion of one of the housing and the dust collection attachment engages with a depressed side engaging portion in a second of the housing and the dust collection attachment by relatively sliding the dust collection attachment in a predetermined straight-line direction with respect to the housing, and

the projecting side engaging portion or the depressed side engaging portion in the housing is separated into a plurality in the straight-line direction.

15. The impact tool according to claim 14 , wherein

the projecting side engaging portion or the depressed side engaging portion is a pair on the left and right sides.

16. A dust collection system comprising:

the impact tool according to claim 1 ; and

the dust collection attachment mounted to the housing with a suction opening for the tool bit, the dust collection attachment generating a suctioning force to the suction opening when the dust collection fan.

17. An impact tool comprising:

a housing having a mounting to receive and retain a dust collection attachment;

an impact mechanism unit (i) inside the housing, (ii) having (a) a front end configured to receive and retain a tool bit and (b) an impact element that reciprocates, and (iii) being configured to impact the tool bit by the impact element when the tool bit is retained by the front end;

a motor having a rotation shaft that intersects an impact axis direction of the impact mechanism unit inside the housing; and

a dust collection fan on the rotation shaft, wherein

the dust collection fan is below the motor,

a lower surface of the housing includes an air inlet that suctions air from outside the housing when the dust collection fan rotates,

the mounting is on an underside of the housing adjacent the dust collection fan, and

the mounting is configured such that the dust collection attachment is attached to and detached from the housing in an up-down direction.