Patent Publication Number: US-2021178568-A1

Title: Dust collector for electric power tool and electric power tool

Description:
BACKGROUND OF THE INVENTION 
     This application claims the benefits of International Application No. PCT/JP2018/045608, filed on Dec. 12, 2018 and Japanese Patent Application Number No. 2017-245347 filed on Dec. 21, 2017, the entirety of which is incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The invention relates to a dust collector for electric power tool mounted to an electric power tool, such as an electric drill and a hammer drill, and an electric power tool to which the dust collector is mounted. 
     BACKGROUND ART 
     To an electric power tool, such as an electric drill and a hammer drill, a dust collector, which collects dust generated from a workpiece in a drilling work and the like, is mounted. Specifically, it is a structure where, by suctioning an air that contains the dust into a body case of the dust collector to cause the air to pass through a filter in a dust box, the dust is captured by the filter and accumulated in the dust box. 
     In the dust collector for electric power tool, when the amount of the dust accumulated on the filter increases with the progress of the work and clogging occurs on the filter, a dust collection efficiency and a product lifetime of the filter decrease. Therefore, Japanese Patent No. 5739268 discloses an invention where a pump in an accordion shape configured to send air by compression from a downstream side toward an upstream side of a filter is disposed in a body case, and the pump is operated to flow the air backward, thereby blowing away dust accumulated on the filter. 
     DISCLOSURE OF THE INVENTION 
     In the conventional dust collector, since the air is flown backward on a dust collecting route from a suction opening portion on a tool bit side to the filter, the dust is possibly accumulated in the middle of the dust collecting route, or the dust is possibly blown out from the suction opening portion by the air flowing backward. Accordingly, the dust collecting route needs to be processed so as to avoid moving of the dust to the suction opening portion side, thus leading to cost increase. 
     Therefore, it is an object of the invention to provide a dust collector for electric power tool configured to easily avoid filter clogging at low cost, and an electric power tool. 
     In order to achieve the above-described object, a first aspect of the invention is a dust collector for electric power tool that includes a casing, a tubular suction opening portion, a dust collecting route, a filter, and a dust removal means. The casing is mountable to an electric power tool. The suction opening portion is disposed to protrude forward from the casing. A tool bit of the electric power tool is passable through the suction opening portion being abutted on a surface to be processed. The dust collecting route is formed in the casing. The dust collecting route suctions an air from the suction opening portion and guides the air into a dust box disposed to the casing. The filter is disposed in the dust box and configured to capture a dust suctioned with the air. The dust removal means is configured to directly act to the filter from outside the dust box to remove the dust accumulated on the filter. 
     In the case, the dust removal means is preferably an elastic member that forms a part of the dust box and has an inner surface abutted on the filter by at least an elastic deformation. 
     The filter is preferably folded in a right-left direction, the elastic member forms the part including right and left side surfaces of the dust box, and the inner surface abuts on right and left side surfaces of the filter. 
     The dust box is preferably made of a resin, and the elastic member is preferably a rubber bonded to the dust box. 
     The rubber preferably has right and left side surfaces where recesses are formed to be inwardly depressed with respect to the resin part of the dust box to abut on the side surfaces of the filter. 
     The dust removal means is preferably disposed to be close to or abutted on the filter in the dust box, and the dust removal means is preferably a dust removal member operatable from outside the dust box. 
     The filter is preferably folded in a right-left direction, and the dust removal member is preferably movable by the operation from outside in an intersecting direction with a mountain folded portion of the filter. 
     The dust removal member is preferably inserted between a plurality of the mountain folded portions. 
     The dust box preferably has right and left side surfaces where operation holes are penetratingly formed, rubbers are preferably bonded in the respective operation holes, and the dust removal member is preferably secured to a support shaft bridged between the rubbers. 
     The dust removal member is preferably rotated by the operation from outside. 
     A dust collection motor is preferably included and the filter is preferably elastically supported, and the dust removal means preferably includes a dust removal member operated by driving of the dust collection motor and an operation member configured to press the filter to the dust removal member side from outside the dust box. 
     The dust removal member is preferably disposed between the dust collection motor and the filter, and the dust removal member is preferably a cam rotated by rotation of an output shaft of the dust collection motor. 
     In order to achieve the above-described object, a second aspect of the invention is an electric power tool that includes the dust collector for electric power tool according to the first aspect mounted thereto. 
     According to the invention, by disposing the dust removal means configured to directly act to the filter from outside the dust box to remove the dust accumulated on the filter, the expansion and contraction, the vibration, and the like of the filter can be directly performed with the dust removal means, thus ensuring the effective dust removal at ease. Accordingly, filter clogging can be easily avoided at low cost. 
     Especially, when the dust removal means is an elastic member that forms a part of the dust box and has an inner surface abutting on the filter, the vibration and the like can be easily applied to the filter from outside using the part of the dust box. The dust removal means does not project outside the dust box and does not become a hindrance. 
     Especially, when the filter is folded in the right-left direction, the elastic member forms a part of the dust box including the right and left side surfaces, and the inner surface of the elastic member abuts on the right and left side surfaces of the filter, the filter can be easily expanded and contracted or vibrated by the operation of the elastic member from outside. 
     Especially, when the dust removal means is disposed to be close to or abutted on the filter in the dust box, and the dust removal means is a dust removal member operatable from outside the dust box, the vibration and the like can be surely and easily applied to the filter. The dust removal member is not exposed outside the dust box and does not become a hindrance. 
     Especially, when the filter is folded in a right-left direction, and the dust removal member is movable by the operation from outside in an intersecting direction with a mountain folded portion of the filter, the filter folded in the right-left direction can be efficiently swung. 
     Especially, when the dust removal member is inserted between the mountain folded portions of the filter, the dust removal member can be surely abutted on the mountain folded portion to be swung. 
     Especially, when the dust removal member is rotated by the operation from outside, the dust removal of the filter can be performed by a simple rotating operation. 
     Especially, when the dust removal means has a configuration that includes a dust removal member operated by driving of the dust collection motor and an operation member configured to press the filter to the dust removal member side from outside the dust box, the effective vibration can be applied to the filter using the dust collection motor. 
     Especially, when the dust removal member is disposed between the dust collection motor and the filter, and the dust removal member is a cam rotated by rotation of an output shaft of the dust collection motor, the rotation of the output shaft can be efficiently transmitted to the filter as the vibration. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a center vertical cross-sectional view of a hammer drill to which a dust collector for electric power tool in an embodiment 1 is mounted. 
         FIG. 2  is a center vertical cross-sectional view of the dust collector for electric power tool in the embodiment 1. 
         FIG. 3  is a perspective view of a dust box in the embodiment 1. 
         FIG. 4A  is a center vertical cross-sectional view of the dust box in the embodiment 1. 
         FIG. 4B  is a cross-sectional view taken along the line A-A of  FIG. 4A . 
         FIG. 5  is a perspective view of a dust box in an embodiment 2. 
         FIG. 6  is a center vertical cross-sectional view of the dust box in the embodiment 2. 
         FIG. 7A  is a cross-sectional view taken along the line B-B of  FIG. 6 . 
         FIG. 7  B is a cross-sectional view taken along the line C-C of  FIG. 6 . 
         FIG. 8A  is a perspective view illustrating the dust box in the embodiment 2 in an opened state. 
         FIG. 8  B is a center vertical cross-sectional view illustrating the dust box in the embodiment in the opened state. 
         FIG. 9A  is a perspective view of a dust box in an embodiment 3. 
         FIG. 9B  is a center vertical cross-sectional view of the dust box in the embodiment 3. 
         FIG. 10A  is a cross-sectional view taken along the line D-D of  FIG. 9B . 
         FIG. 10B  is a cross-sectional view taken along the line E-E of  FIG. 9B . 
         FIG. 11A  is a perspective view of a dust box in an embodiment 4. 
         FIG. 11B  is a center vertical cross-sectional view of the dust box in the embodiment 4. 
         FIG. 12  is a cross-sectional view taken along the line F-F of  FIG. 11B . 
         FIG. 13  is a perspective view of a dust collector for electric power tool in an embodiment 5. 
         FIG. 14  is a center vertical cross-sectional view of the dust collector for electric power tool in the embodiment 5. 
     
    
    
     EMBODIMENTS 
     The following describes embodiments of the invention based on the drawings. 
     An embodiment 1 of the invention will be described below. 
       FIG. 1  illustrates a center vertical cross-section in a state where a dust collector for electric power tool (hereinafter simply referred to as a “dust collector”)  40  is mounted to a hammer drill  1  as an exemplary electric power tool. 
     First, the hammer drill  1  houses a motor (brushless motor)  3  having an output shaft  4  facing upward in a front lower portion of a housing  2  formed by assembling a pair of right and left half housings. On the upper side of the motor  3 , an intermediate shaft  6 , to which a torque is transmitted via bevel gears  5 ,  5 , is supported in a front-rear direction, and the intermediate shaft  6  includes a first gear  7 , a clutch  8 , and a boss sleeve  9  from the front side. On the upper side of the intermediate shaft  6 , a tool holder  10 , which has a tip where a bit (not illustrated) as a tool bit is mountable, is pivotally supported parallel to the intermediate shaft  6 . An arm  13  is coupled to a rear end of a piston cylinder  11  movably inserted into a rear portion of the tool holder  10 , and the arm  13  is externally mounted to the boss sleeve  9  via a swash bearing  12 . Inside the piston cylinder  11 , a striker  15  is mounted to be movable back and forth via an air chamber  14 , and the striker  15  is configured to hammer an impact bolt  16  disposed ahead of the striker  15 . The first gear  7  is engaged with a second gear  17  mounted to the tool holder  10 . 
     At a rear upper portion of the housing  2 , a handlebar  18  that includes a switch  19  and a switch lever  20  is formed. Downward the handlebar  18 , a battery mounting portion  21 , to which a battery pack  22  as a power source is slidingly mounted from the rear side, is disposed. Inside the battery mounting portion  21 , a terminal block  23  electrically coupled to the mounted battery pack  22  is disposed. 
     The front lower portion of the housing  2  has a front surface inclined forward and downward, and projects to the front of the battery pack  22 , thus forming a mounting portion  24  to which the dust collector  40  is mounted. The mounting portion  24  internally houses the motor  3 , and a controller  25  is housed in the front-rear direction below the mounting portion  24 . The controller  25  is electrically coupled to the motor  3 , the switch  19 , and the terminal block  23 , and includes a circuit substrate that includes a microcomputer, a switching element, and the like. 
     On the front upper side of the controller  25 , a connector  26  is disposed, in which three female terminals for power source and communication are arranged side by side in a right-left direction. An insertion port  27  is provided to be open ahead of the connector  26  on a front surface of the mounting portion  24 . The connector  26  is supported swingably in the up-down direction around the rear end, and biased by a torsion spring  28  to a lower limit position to close the insertion port  27  with a shutter portion  29  disposed on an upper portion. Below the connector  26 , a press bar  30  is disposed movable up and down, and the press bar  30  projects to a lower surface of the mounting portion  24  at the lower limit position of the connector  26 . In the center in the right-left direction on the lower surface of the mounting portion  24 , a lower depressed portion  31 , to which the press bar  30  projects, is formed while the front side and the lower surface are open. On both side surfaces of the mounting portion  24  corresponding to right and left of the lower depressed portion  31 , guide grooves (not illustrated) for slidingly mounting the dust collector  40  are formed in the front-rear direction. 
     The dust collector  40  includes, as illustrated in  FIG. 2 , a casing  41  having an L shape in side view formed by assembling right and left half casings, and on the rear upper portion, a fitting depressed portion  42  is formed to fit to the mounting portion  24  of the hammer drill  1 . A dust collection motor  43  with an output shaft  44  facing forward is housed to face forward in a rear lower portion of the casing  41 , and a dust collection controller  45  is disposed rearward the dust collection motor  43 . A dust collection fan  46  is fixedly secured to the output shaft  44 , and is housed in an intake air chamber  48  that is defined in the casing  41  and includes exhaust outlets  47 ,  47  . . . ( FIG. 13 ) on side surfaces. A joint  49  of a dust box  65  is formed ahead of the intake air chamber  48  at the lower portion on the front surface of the casing  41 , and the joint  49  has a depressed shape while the front side is open. A communication hole  51  is provided to a partition wall  50  as a bottom of the joint  49  on the rear side, and the communication hole  51  communicates the joint  49  with the intake air chamber  48  coaxially with the dust collection fan  46 . 
     Plate-shaped three male terminals  52 ,  52  . . . for power source and communication are arranged side by side at predetermined intervals in the right-left direction on an upper rear surface of the casing  41 , and project rearward. 
     On both right and left sides on a rear top surface of the casing  41 , a pair of guide rails  53 ,  53 , which are fittable to the guide grooves on the right and left side surfaces of the mounting portion  24 , are disposed upright in the front-rear direction. Between the guide rails  53 ,  53  on the rear top surface of the casing  41 , a push-up member  54  is disposed having a rear surface as a surface inclined rearward and downward, and the push-up member  54  enters the lower depressed portion  31  in the fitted state of the mounting portion  24  to push the press bar  30  upward. 
     On the on upper side of the joint  49  inside the casing  41 , a guide passage  55  is formed in the front-rear direction, and the guide passage  55  has an open front end and a rear end bent in a U shape to go around to the rear of the joint  49 . To the guide passage  55 , a slide tube  56  is coupled in a state of being movable in the front-rear direction and biased to project, and an L-shaped nozzle  57  having a tip facing upward is coupled to the front end of the slide tube  56 . At the tip of the nozzle  57 , a tubular suction opening portion  58  through which the bit coaxially passes is formed. 
     The guide passage  55  and the slide tube  56  internally houses a flexible hose  59  whose front end is coupled to the nozzle  57 , and a rear end of the flexible hose  59  is coupled to a tubular duct  60  folded in a U shape along the shape of the rear end of the guide passage  55 . The duct  60  has a lower end portion passing through the partition wall  50  to project inside the joint  49 . At the lower end of the joint  49  ahead of the partition wall  50 , a receiving shaft  61  in the right-left direction is disposed to protrude, and a lock protrusion  62  locked to the upper side of the dust box  65  is formed at a position close to the front side on an upper inner surface of the joint  49 . 
     As illustrated in  FIGS. 3, 4A and 4B , the dust box  65  includes a box main body  66  that has an open rear surface and has a deep bottom box shape and a lid body  68  in a vertically long rectangular shape rotatably coupled to the lower side of the box main body  66  by a hinge shaft  67  on the open side. For the dust box  65  alone, a description will be given with the front-back, right-left, and up-down directions identical to those in a state of being mounted to the hammer drill  1 . 
     To the upper end portion of the lid body  68 , a loop-shaped lock portion  69  is disposed, and the lock portion  69  is engaged with the top surface of the box main body  66  in a state where the opening of the box main body  66  is closed and keeps the closed state. On the upper end side of the lid body  68 , an inlet  70  in a laterally long rectangular shape is disposed, and the lower end portion of the duct  60  is inserted into the inlet  70  in a state of being mounted to the joint  49 . On the lower end side, an outlet  71  in a circular shape is formed, and the outlet  71  is opposed to the communication hole  51  in, similarly, the state of being mounted. At a position covering the outlet  71 , a filter housing portion  72 , which holds a paper filter  73  folded in the right-left direction having a fold in the up-down direction, is disposed to protrude into the box main body  66 . In the state, the filter  73  has mountain folded portions  73   a,    73   a,  . . . , which are formed in the up-down direction on the front surface, exposed at regular intervals in the right-left direction, and the right and left surfaces are also exposed inside the box main body  66 . 
     On the lower surface of the box main body  66 , a groove  74  fitted to the receiving shaft  61  of the joint  49  is formed, and on the upper surface, an operation piece  75  that includes a protrusion  76  elastically locked to the lock protrusion  62  of the joint  49  is formed. 
     While the box main body  66  is made of a resin, only a region across the front surface and right and left side surfaces having a predetermined width on an intermediate portion in a longitudinal direction, which is the outer side of the filter housing portion  72 , is made of a rubber  77  as a vulcanized and bonded elastic member. On right and left side surfaces of the rubber  77 , recesses  78 ,  78  are formed to be inwardly depressed with respect to the resin part to abut on the side surface of the filter  73 . Accordingly, by pinching the right and left recesses  78 ,  78  from both sides to press inward, the rubber  77  is elastically deformed to abut on the filter  73 , thus ensuring directly deforming the filter  73  in the right-left folding direction. The rubber  77  may be mounted by, for example, a recess-projection fitting of the end portion of the rubber  77  into the opening formed at a corresponding region of the box main body  66 , not limited to the vulcanization bonding. The same applies to a rubber in an embodiment 2. 
     By pushing thus formed dust box  65  into the joint  49  so as to be erected from an oblique posture where the lid body  68  is faced rearward and the groove  74  is fitted to the receiving shaft  61  from the front side, the protrusion  76  of the operation piece  75  is locked to the lock protrusion  62  to mount the dust box  65  to the joint  49 . In the mounting state, the distal end portion of the duct  60  is fitted to the inlet  70  and projects to the inside of the box main body  66 , and the outlet  71  is opposed to the communication hole  51 , thereby providing the communication with the intake air chamber  48 . Accordingly, in the dust collector  40 , a dust collecting route R ( FIGS. 1, 2 ) is formed from the suction opening portion  58  to the intake air chamber  48  passing through the filter  73  in the box main body  66  via the nozzle  57 , the flexible hose  59 , and the duct  60 . 
     In the hammer drill  1  and the dust collector  40  configured as described above, when the dust collector  40  is mounted to the hammer drill  1 , the guide rails  53 ,  53  of the casing  41  are mated to the lower portion of the mounting portion  24  of the hammer drill  1  to position the mounting portion  24  on the rear portion of the casing  41 . In such a state, the dust collector  40  is slid rearward so as to fit the fitting depressed portion  42  to the mounting portion  24  from the front. Then, the guide rails  53 ,  53  fit to the right and left guide grooves of the mounting portion  24  and the mounting portion  24  is coupled between the guide rails  53 ,  53 . At the same time, the push-up member  54  enters the lower depressed portion  31  to push up the press bar  30  and swings the connector  26  to an upper limit position at which the shutter portion  29  is retreated upward to be opposed to the insertion port  27 . Accordingly, the male terminal  52  of the dust collector  40  enters into the housing  2  from the insertion port  27 , and is electrically coupled to the female terminal of the connector  26  ( FIG. 1 ). 
     Then, in a set state where the suction opening portion  58  is pressed against a surface to be processed of a workpiece, turning the switch  19  ON by performing a push-in operation of the switch lever  20  of the hammer drill  1  drives the motor  3  to rotate the intermediate shaft  6 . At the time, operating a switching knob (not illustrated) disposed on the side surface of the housing  2  causes the clutch  8  to slide to select any one of an advance position, a retreated position, and an intermediate position. The advance position is a position where the clutch  8  engages only with the first gear  7 , a retreated position is a position where the clutch  8  engages only with the boss sleeve  9 , and an intermediate position is a position where the clutch  8  simultaneously engages with the first gear  7  and the boss sleeve  9 . Thus, a selection of a drill mode, a hammer mode, and a hammer drill mode can be made. The drill mode is a mode in which the tool holder  10  rotates via the second gear  17  to rotate the bit. The hammer mode is a mode in which the piston cylinder  11  is caused to reciprocate by a swing of the arm  13  and the striker  15  in conjunction with the piston cylinder  11  hammers the bit via the impact bolt  16 . The hammer drill mode is a mode in which the rotation of the tool holder  10  and the hammering of the impact bolt  16  are simultaneously performed. When the hammer drill  1  is caused to make a forward movement in a state where the suction opening portion  58  is set, the slide tube  56  retreats together with the nozzle  57 , and the bit passes through the suction opening portion  58  to be able to process the workpiece. 
     By turning the switch  19  ON, the controller  25  supplies electric power to the dust collection controller  45  of the dust collector  40 . Then, the dust collection controller  45  drives the dust collection motor  43  to rotate the dust collection fan  46 . Accordingly, an external air is suctioned from the suction opening portion  58  and discharged inside the dust box  65  passing through the flexible hose  59  and the duct  60  from the nozzle  57 . Subsequently, the external air passes through the filter housing portion  72  to reach the intake air chamber  48  from the outlet  71  via the communication hole  51 , and is discharged outside from the exhaust outlet  47 . Therefore, the dust generated from the workpiece is suctioned by the suction opening portion  58 , enters inside the dust box  65  via the nozzle  57 , the flexible hose  59 , and the duct  60 , and is captured by the filter  73  when passing through the filter housing portion  72 , thereby being accumulated inside the box main body  66 . 
     When the push-in of the switch lever  20  is released to turn the switch  19  OFF, the motor  3  stops and the rotation and the like of the bit stop. However, since the controller  25  has a delay function to stop the energization of the dust collector  40  with a delay by several seconds from the tuning the switch  19  OFF, in the dust collector  40 , the dust collection fan  46  continues to rotate for several seconds after the bit stop. Accordingly, the dust remaining in the nozzle  57 , the flexible hose  59 , and the like also can be surely collected in the dust box  65 . 
     Then, in removal of the dust collector  40 , conversely to the mounting, by sliding the dust collector  40  forward from the hammer drill  1 , the fitting depressed portion  42  is released from the mounting portion  24 , and the male terminal  52  is separated from the connector  26  and pulled out from the insertion port  27 . The connector  26  returns to the lower limit position and the shutter portion  29  closes the insertion port  27 . 
     In disposal of the dust accumulated in the dust box  65 , the dust box  65  can be removed from the joint  49  by pressing down the operation piece  75  to release the lock of the protrusion  76  to the lock protrusion  62  and directly bringing the upper side down forward around the receiving shaft  61 . Accordingly, by releasing the lock portion  69  of the lid body  68  from the box main body  66  to open the lid body  68 , the dust can be disposed from the opening of the box main body  66 . 
     Before the disposal, when the recesses  78 ,  78  of the rubber  77  of the box main body  66  are sandwiched from both sides to elastically deform the recesses  78 ,  78  in a manner of pushing inward for multiple times, the filter  73  expands and contracts in the folding direction. Therefore, the dust accumulated on the filter  73  can be removed inside the box main body  66 . The dust removal can be performed also by vibrating the filter  73  by flicking or hitting the recess  78  with a finger in addition to sandwiching the recesses  78 ,  78 . Not limited to the timing of disposing the dust, the dust removal may be performed at an interval of the machining work. 
     As described above, according to the dust collector  40  and the hammer drill  1  of the embodiment 1, by disposing a dust removal means (rubber  77 ) configured to directly act to the filter  73  from outside the dust box  65  to remove the dust accumulated on the filter  73 , the expansion and contraction, the vibration, and the like of the filter  73  can be directly performed with the rubber  77 , thus ensuring the effective dust removal at ease. Accordingly, clogging of the filter  73  can be easily avoided at low cost. 
     Especially, here, since the dust removal means is an elastic member (rubber  77 ) that forms a part of the dust box  65  and has an inner surface abutting on the filter  73 , the vibration and the like can be easily applied to the filter  73  from outside using the part of the dust box  65 . The dust removal means does not project outside the dust box  65  and does not become a hindrance. 
     The filter  73  is folded in the right-left direction, the rubber  77  forms a part of the dust box  65  including the right and left side surfaces, and the inner surface of the rubber  77  abuts on the right and left side surfaces of the filter  73 . Therefore, the filter  73  can be easily expanded and contracted or vibrated by the operation of the rubber  77  from outside. 
     In the above-described embodiment, the inner surface of the rubber abuts on the side surfaces of the filter in an ordinary state. However, the inner surface of the rubber may be positioned at the proximity without contact in the ordinary state, and the rubber may abut on the side surface of the filter by an inward elastic deformation. Accordingly, the recess is not necessary to be provided. 
     The rubber formed region is not limited to the region across the front surface and the right and left side surfaces having the predetermined width of the dust box, and for example, the rubber may be separately formed only on the right and left side surfaces while the front surface is omitted, or may be formed on only one side surface of the right and the left. Furthermore, depending on the form of the filter, the rubber can be formed on the top surface and the bottom surface of the dust box. 
     Next, other embodiments of the invention will be described. However, like reference numerals designate identical components of the hammer drill  1 , the casing  41  of the dust collector  40 , and the like to omit overlapping descriptions. A dust box  65 A of an embodiment 2 will be described below. 
     In the dust box  65 A illustrated in  FIGS. 5 to 7B , on the right and left side surfaces of the front lower portion of the box main body  66 , a pair of right and left operation holes  80 ,  80  are penetratingly formed, and respective rubbers  81 ,  81  are vulcanized and bonded in a manner of covering both operation holes  80 . Between the right and left rubbers  81 ,  81  inside the box main body  66 , a support shaft  82  is bridged in the right-left direction, and a plurality of dust removal plates  83 ,  83 , . . . are secured to the support shaft  82  at predetermined intervals in a comb shape. The plurality of dust removal plates  83 ,  83 , . . . have inverted L shape in side view standing upward and subsequently bending rearward. The dust removal plates  83  have respective rear ends inserted between the mountain folded portions  73   a,    73   a,  . . . on the front surface of the filter  73  to abut on the side surfaces of the mountain folded portions  73   a,    73   a, . . . .    
     In the dust box  65 A configured as described above, by placing fingers to sandwich the rubbers  81 ,  81  from the right and left operation holes  80 ,  80 , and directly swinging to right and left, the rubbers  81 ,  81  can be elastically deformed to slide the support shaft  82  to right and left in the box main body  66 . Since the slide causes the respective dust removal plates  83  to interfere with the mountain folded portions  73   a  of the filter  73  to swing each mountain folded portion  73   a  to right and left, the dust accumulated on the filter  73  can be removed inside the box main body  66 . 
     When the dust inside the box main body  66  is disposed, since opening the lid body  68  as illustrated in  FIGS. 8A and 8B  relatively pulls out the dust removal plates  83 ,  83 , . . . inside the box main body  66  from between the mountain folded portions  73   a,    73   a,  . . . , the operation of the lid body  68  is not obstructed. After the disposal of the dust, when the lid body  68  is closed, the respective dust removal plates  83  are inserted between the mountain folded portions  73   a,    73   a,  . . . again. 
     As described above, according to also the dust collector  40  and the hammer drill  1  of the embodiment 2, by disposing a dust removal means (dust removal plate  83  as a dust removal member) configured to directly act to the filter  73  from outside the dust box  65 A to remove the dust accumulated on the filter  73 , the filter  73  can be, for example, directly swung by the dust removal plate  83 , thus ensuring the effective dust removal at ease. Accordingly, clogging of the filter  73  can be easily avoided at low cost. 
     Especially, here, since the dust removal means is the dust removal plate  83  that is disposed to abut on the filter  73  inside the dust box  65 A and configured to be operated from outside the dust box  65 A, the vibration and the like can be surely and easily applied to the filter  73 . The dust removal plate  83  is not exposed outside the dust box  65 A and does not become a hindrance. 
     Since the dust removal plates  83  are configured to be moved in an intersecting direction with the mountain folded portions  73   a,    73   a,  . . . by the operation from outside, the filter  73  folded in the right-left direction can be efficiently swung. 
     Furthermore, since the dust removal plates  83  are inserted between the mountain folded portions  73   a,    73   a,  . . . of the filter  73 , the dust removal plates  83  can be surely abutted on the mountain folded portions  73   a,    73   a,  . . . to be swung. 
     The number and the shape of the dust removal plate are not limited to the above-described embodiment. For example, not the L shape but an arc shape or a linear shape may be employed, or not abutting on the mountain folded portion but positioning at the proximity may be employed in the ordinary state. 
     The rubber that supports the support shaft may be disposed at any one instead of disposing at both right and left ends. Not limiting to the structure supporting via the rubber, the following structures may be employed, such as a structure where both ends of the support shaft are projected from the right and left side surfaces of the box main body and the both ends of the support shaft are gripped to be slid right and left, and a structure where a large diameter portion is disposed at any one of the right and left projecting ends of the support shaft, a coil spring is externally mounted between the side surface of the box main body and the large diameter portion, and the support shaft is slid by a press operation of the large diameter portion. The location of the support shaft may be upper side compared with that of the above-described embodiment. 
     An embodiment 3 of the invention will be described below. 
     In a dust box  65 B illustrated in  FIGS. 9A to 10B , a rotation shaft  85  is disposed in the up-down direction ahead of the filter  73  in the center in the right-left direction inside the box main body  66 . At the upper end of the rotation shaft  85 , a plurality of dust removal blades  86 ,  86 , . . . are mounted in the radiation direction. The dust removal blade  86  is formed of a material, such as a resin and a rubber, having flexibility, and a rotation locus of the tip of the dust removal blade  86  is configured to intersect with the plurality of mountain folded portions  73   a,    73   a,  . . . on the front surface of the filter  73  in plan view. The rotation shaft  85  has a lower end that passes through the lower portion of the box main body  66  to project to the lower side, and an operation dial  87  that allows a rotating operation from the outside of the dust box  65 B is disposed to the lower end of the rotation shaft  85 . 
     In the dust box  65 B configured as described above, by the rotation operation of the operation dial  87  on the lower side of the box main body  66  in any of the clockwise or the counterclockwise direction, the rotation shaft  85  rotates inside the box main body  66 , and in accordance with it, the dust removal blades  86 ,  86 , . . . rotate. Since the rotation of the dust removal blade  86  causes the respective dust removal blades  86  to abut on the mountain folded portions  73   a  of the filter  73  to provide swing or vibration, the dust accumulated on the filter  73  can be removed inside the box main body  66 . 
     As described above, according to also the dust collector  40  and the hammer drill  1  of the embodiment 3, by disposing a dust removal means (dust removal blade  86  as a dust removal member) configured to directly act to the filter  73  from outside the dust box  65 B to remove the dust accumulated on the filter  73 , the filter  73  can be directly swung or vibrated by the dust removal blade  86 , thus ensuring the effective dust removal at ease. Accordingly, clogging of the filter  73  can be easily avoided at low cost. 
     Especially, here, since the dust removal member is the dust removal blade  86  rotated by the operation from outside, the dust removal of the filter  73  can be performed by the simple rotating operation. 
     The number and the shape of the dust removal blade are not limited to the above-described embodiment, and can be changed as necessary. The size is changeable, and the length can be changed for each dust removal blade. While the dust removal blade is disposed only to the upper end of the rotation shaft in the above-described embodiment, the dust removal blades may be radially mounted at a respective plurality of positions in the up-down direction by extending the rotation shaft upward, thereby causing the dust removal blades to abut on the mountain folded portions at the plurality of positions. In the case, the size of the dust removal blade and the number of the blades can be changed for each mounting position (for example, the size of the blade can be increased or the number of the blades can increased on the center side of the filter compared with the lower end side). Furthermore, a plurality of rotation shafts may be arranged right and left, and the dust removal blades are disposed to the respective rotation shafts to allow the rotating operation. When the space allows, the rotation shaft may be passed through from not the lower side but the upper side. 
     An embodiment 4 of the invention will be described below. 
     In a dust box  65 C illustrated in  FIGS. 11A, 11B and 12 , a rotation shaft  90  is disposed in the right-left direction ahead of the filter  73  in the center in the up-down direction inside the box main body  66 . The rotation shaft  90  is passed through the inside of the box main body  66  from the left side surface and rotatably cantilevered. In the box main body  66 , large diameter portions  91 ,  91  having a lateral cross-sectional surface in a circular shape are formed with an interval in the right-left direction. The large diameter portions  91 ,  91  are disposed at the tip and an intermediate portion of the rotation shaft  90  positioned ahead of the filter  73 . To the respective large diameter portions  91 ,  91 , a plurality of dust removal brushes  92 ,  92 , . . . formed of a bundle of brush hair are implanted in the radiation direction. The rotation locus of the tip of the dust removal brush  92  is configured to exceed the mountain folded portion  73   a  on the front surface of the filter  73  to reach the rear side in side view, and interfere with the right and left side surfaces of the mountain folded portion  73   a.  The rotation shaft  90  has a left end that passes through the side surface of the box main body  66  to project to the left side, and an operation dial  93  that allows a rotating operation from the outside of the dust box  65 C is disposed to the left end of the rotation shaft  90 . 
     In the dust box  65 C configured as described above, by the rotation operation of the operation dial  93  on the side of the box main body  66  in any of the clockwise or the counterclockwise direction, the rotation shaft  90  rotates inside the box main body  66 , and in accordance with it, the right and left large diameter portions  91 ,  91  rotate to rotate the dust removal brush  92 ,  92 , . . . . Since the rotation of the dust removal brush  92  causes the respective dust removal brushes  92  to abut on the side surfaces of the mountain folded portions  73   a  of the filter  73  to provide swing or vibration, the dust accumulated on the filter  73  can be removed inside the box main body  66 . 
     As described above, according to also the dust collector  40  and the hammer drill  1  of the embodiment 4, by disposing a dust removal means (dust removal brush  92  as a dust removal member) configured to directly act to the filter  73  from outside the dust box  65 C to remove the dust accumulated on the filter  73 , the filter  73  can be directly swung or vibrated by the dust removal brush  92 , thus ensuring the effective dust removal at ease. Accordingly, clogging of the filter  73  can be easily avoided at low cost. 
     Especially, here, since the dust removal member is the dust removal brush  92  rotated by the operation from outside, the dust removal of the filter  73  can be performed by the simple rotating operation. 
     The number and the shape of the dust removal brush are also not limited to the above-described embodiment, and can be changed as necessary. The size is changeable, and the length can be changed for each dust removal brush. While the large diameter portions are disposed at two positions of the rotation shaft and the dust removal brushes are implanted to each of them in the above-described embodiment, the number of the large diameter portions also can be increased and decreased as necessary. The operation dial may be disposed at the opposite end portion of the rotation shaft, or may be disposed at both ends. Furthermore, a plurality of rotation shafts to which the dust removal brushes are implanted may be disposed in an arrangement of up and down, and each allow the rotating operation. 
     An embodiment 5 of the invention will be described below. 
     In a dust box  65 D illustrated in  FIGS. 13 and 14 , the filter housing portion  72  is disposed to be separated forward from the lid body  68 , and elastically supported swingable in all the directions of up-down, right-left, oblique, and front-rear in the box main body  66  via an elastic rubber  95 . The elastic rubber  95  has a bellow tubular shape and has respective end portions coupled to the rear surface of the filter housing portion  72  and the front surface of the lid body  68  at a region surrounding the outlet  71 . However, four coil springs  96 ,  96 , . . . are disposed at respective four corners of the rear surface of the filter housing portion  72  between the filter housing portion  72  and the lid body  68  in the elastic rubber  95 . Therefore, the filter housing portion  72  is biased forward, in which the elastic rubber  95  expands, by the coil springs  96 ,  96 , . . . . To a portion opposing the outlet  71  of the lid body  68  on the rear surface of the filter housing portion  72 , a front cam  97  is secured. The front cam  97  projects to the outlet  71  side and has a rear surface on which a front cam surface  98  having radial unevenness is formed. 
     At a portion opposing the center in the up-down and the right-left directions of the filter  73  on the front surface of the box main body  66 , a circular depressed portion  99  projecting inward is disposed. A button shaft  100  that orthogonally penetrates the bottom surface of the circular depressed portion  99  and has a tip projecting inside the box main body  66  is disposed movable back and forth. The button shaft  100  has a front end at which a flange portion  101  having a diameter larger than an inner diameter of the circular depressed portion  99  is formed. The button shaft  100  has a rear end at which a clip  102  is disposed to retain the button shaft  100  on the rear side of the circular depressed portion  99 . A coil spring  103  is externally mounted to the button shaft  100  between the flange portion  101  and the bottom surface of the circular depressed portion  99 , and the button shaft  100  is biased by the coil spring  103  to a projecting position where the clip  102  abuts on the rear surface of the circular depressed portion  99 . The central portions of the mountain folded portions  73   a,    73   a,  . . . of the filter  73  in the filter housing portion  72  biased forward abut on the rear end of the button shaft  100  at the projecting position. 
     Then, the front end of the output shaft  44  of the dust collection motor  43  passes through the communication hole  51  and projects forward, and a rear cam  104  is integrally secured to the projecting portion. The rear cam  104  is opposed to the front cam  97  of the filter housing portion  72 , and has a front surface on which a rear cam surface  105  having radial unevenness is formed. 
     In the dust collector  40  configured as described above, during the machining work (during the driving of the dust collection motor  43 ), when an operation to push the button shaft  100  of the dust box  65 D rearward against the biasing by the coil spring  103  is performed, the filter housing portion  72  retreats against the biasing by the coil springs  96 ,  96 , . . . via the filter  73  of which the mountain folded portions  73   a,    73   a,  . . . abut on the button shaft  100 . Then, the front cam surface  98  of the front cam  97 , which has simultaneously retreated, is engaged with the rear cam surface  105  of the rear cam  104  that rotates with the output shaft  44 , thereby transmitting the vibration to the front cam  97  and the filter housing portion  72  by the engagement of both cam surfaces  98 ,  105 . By the vibration, the dust accumulated on the filter  73  can be removed. By releasing the pushing operation of the button shaft  100 , the filter housing portion  72  is moved forward by the biasing by the coil springs  96 ,  96 , . . . to separate the front cam  97  from the rear cam  104 . 
     As described above, according to also the dust collector  40  and the hammer drill  1  of the embodiment 5, by disposing a dust removal means (rear cam  104  as a dust removal member, button shaft  100  as an operation member) configured to directly act to the filter  73  from outside the dust box  65 D to remove the dust accumulated on the filter  73 , the filter  73  can be directly vibrated by the rear cam  104 , thus ensuring the effective dust removal at ease. Accordingly, clogging of the filter  73  can be easily avoided at low cost. 
     Especially, here, since the dust removal means has the configuration that includes the rear cam  104  operated by the driving of the dust collection motor  43  and the button shaft  100  configured to press the filter  73  to the rear cam  104  side from outside the dust box  65 D, the effective vibration can be applied to the filter  73  using the dust collection motor  43 . 
     Since the dust removal member is the rear cam  104  that is disposed between the dust collection motor  43  and the filter  73  and is rotated by the rotation of the output shaft  44  of the dust collection motor  43 , the rotation of the output shaft  44  can be efficiently transmitted to the filter  73  as the vibration. 
     The shapes and the lengths of the front cam and the rear cam can be changed as necessary. However, the front cam is not required, and the vibration can be applied to the filter by directly bringing the rear cam in contact with the rear surface of the filter housing portion retreated by the press of the button shaft without the front cam. The number and the arrangement of the coil springs that bias the filter housing portion also can be changed as necessary, and the filter housing portion may be movable not in all the directions but in only the front-rear direction. 
     In addition, commonly to the embodiments, the configuration of the hammer drill can be changed as necessary in the direction and the type of the motor, the arrangement of the battery pack, and the like. An AC machine that includes a power supply cord may be employed instead of the battery pack. The power supply to the dust collector can be changed as necessary, for example, the relationship between the male terminal and the female terminal may be inverted, or terminal portions mutually abutting may be disposed at a joining part of the mounting portion and the fitting depressed portion instead of insertion of the terminal. Needless to say, not limited to the dust collector that includes the motor and the dust collection fan, the dust removal means of the invention is employable even in a configuration that includes only the filter and obtains a suctioning force from a fan disposed to the electric power tool. 
     Then, the electric power tool is not limited to the hammer drill, and the invention is applicable to other models, such as an electric drill, insofar as the dust collector is mountable.