JP2013184258A - Dust collection adapter and power tool including the dust collection adapter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent biting of powder dust or the like into a spring member so as to smoothly execute processing work for objects to be processed by allowing a holder provided with a seal member to move smoothly, thereby improving workability of a power tool.SOLUTION: A dust collection adapter 20 is attached to a power tool body 10a of a disc grinder 10 as a power tool. The dust collection adapter 20 has a dust collection fan 22 and a dust collection cover 21. The dust collection cover 21 has a fan case part 34 for housing the dust collection fan 22 therein, and a tool cover part 41. An annular holder 45 is mounted with a seal member 46 that covers the exterior of a grinding wheel 23 as a tip tool, and is freely movably guided by the tool cover part 41. A leaf spring 48 to bias the holder 45 forward is arranged in a spring chamber 47. Shielding walls 51, 52 to partition the spring chamber 47 are respectively provided on the front face of the fan case part 34 and the back face of the holder.

Description

  The present invention relates to a power tool such as a disk grinder that processes an object to be processed with a tip tool, and a dust collecting adapter that is attached to the power tool and collects dust generated during processing.

  There is a disc grinder or the like as a power tool for processing a surface of an object to be processed by rotationally driving a tip tool such as a rotating grindstone by a power source. The disc grinder is used for grinding the surface of the workpiece by rotating the tip tool with an electric motor or an air motor. As the tip tool, there are a disc-shaped grindstone, a diamond cutter, a cup-shaped grindstone, a wire brush, and the like, and an arbitrary tip tool is selected according to the type of workpiece. For example, in order to grind the surface of an object to be treated such as concrete or stone, a diamond cutter is selected as a tip tool, and the surface is ground by a power tool. A power tool that grinds the surface of an object to be processed with a tip tool is also called a disc sander or a polisher.

  When a worker uses a disk grinder or the like to perform building construction or renovation, when using a concrete floor or wall as an object to be processed, the inclination is corrected, or when tiled flattening is performed, grinding dust is generated. Occur. Since this grinding dust will be scattered at the work site, the operator needs to protect the entire body as well as wearing glasses and a mask to prevent the grinding dust from adhering to the body. .

  There are types of power tools, such as a disc grinder and a disc sander, that perform grinding with a tip tool so as to prevent dust generated during processing from scattering to the outside and to prevent dust from scattering to the outside. Patent Document 1 describes a disk sander in which a protective cover that covers the outer peripheral surface of a grinding disk as a tip tool is attached to a sander body using a spring metal fitting. Patent Document 2 discloses a dust collection cover in which a main body cover that covers a grinding cup is connected via a plurality of springs arranged between a member attached to a gear case of a grinder and a member attached to the main body cover. Have been described. Furthermore, Patent Document 3 describes a surface sharpening device in which a fan is built in a fan casing of a dust collection cover attached to the device body, and the fan is driven by a rotating shaft that drives a sanding wheel. Dust is discharged outside by a hose.

Japanese Patent Laid-Open No. 2005-288656 Japanese Patent No. 4710035 JP 11-129159 A

  As described in Patent Documents 1 and 2, when a cover member that covers a tip tool such as a disk sander is attached to the power tool main body via a spring member, even if excessive stress is applied to the cover member during grinding operation, the cover member Can be prevented from being damaged. However, when the cover member is attached to the main body of the power tool via the spring member, it is necessary to secure a space for arranging the spring member above the cover member and a space for moving the cover member. For this reason, in the power tool in which the fan is arranged inside the cover member, external air is sucked from the extra space, and the dust collecting performance of the fan is lowered.

  In the power tool in which the fan is arranged in the cover, in order to increase the dust collecting and discharging ability by the fan, it is necessary to keep the sealing performance in the cover, as described in Patent Document 3, The cover is provided with a dustproof brush as a sealing member so as to surround the outer periphery of the tip tool. The dust-proof brush is biased by a spring force in a direction of protruding forward of the cover by a spring member such as a leaf spring so that the dust-proof brush can move following the unevenness of the surface to be processed.

  If the spring member is disposed so as to be exposed to the tip tool, dust scattered by the tip tool may bite into the spring member, and the dust brush as the seal member cannot be moved smoothly. For this reason, durability of a power tool falls, it becomes impossible to perform the processing operation | work of the to-be-processed object using a power tool smoothly, and workability | operativity falls.

  An object of the present invention is to improve workability of a power tool.

  A dust collecting adapter according to the present invention is a dust collecting adapter that collects dust generated when a workpiece is processed by a tip tool that is rotationally driven by a main body spindle of a power tool main body, and is rotationally driven by the main body spindle. A dust collecting fan, a fan case portion mounted on the power tool main body and containing the dust collecting fan, and an annular member provided on the front surface of the fan case portion and mounted with a seal member covering the outside of the tip tool A dust collecting cover having a tool cover part that guides the holder movably, and a spring that is arranged in a spring chamber formed between the holder and the front surface of the fan case part, and biases the holder forward. The spring is provided by a member, and at least one of the front surface of the fan case portion and the back surface of the holder, and the tool cover portion. And having an annular shield wall that partitions the.

  The dust collecting adapter of the present invention has a fixed-side shielding wall provided on the front surface of the fan case portion and a movable-side shielding wall provided on the back surface of the holder, and the holder faces the fan case portion. The movable-side shielding wall and the fixed-side shielding wall overlap each other in the radial direction. In the dust collecting adapter of the present invention, the outer diameter of the fixed-side shielding wall is smaller than the inner diameter of the movable-side shielding wall, and when the holder moves toward the fan case portion, The shielding wall overlaps the outside of the fixed-side shielding wall. In the dust collecting adapter of the present invention, the spring member disposed in the spring chamber is a leaf spring. In the dust collection adapter of the present invention, the inner peripheral surface of the holder is a tapered surface having an inner diameter that decreases from the front side toward the back side, and a plurality of the dust collection adapters in a direction along the flow of suction air generated by the dust collection fan. A rib is provided on the tapered surface.

  The power tool of the present invention includes a power tool main body provided with a main body spindle for rotationally driving the tip tool, a cover mounting portion provided in the power tool main body, and the above-described dust collecting cover mounted on the cover mounting portion. It is characterized by having.

  The dust collection cover has a fan case portion that houses the dust collection fan, and a tool cover portion that guides the holder on which a seal member that covers the outside of the tip tool is movably mounted. A spring member that biases the holder forward is accommodated in the spring chamber formed therebetween. Since at least one of the front surface of the fan case portion and the back surface of the holder is provided with an annular shielding wall that divides the spring chamber by the tool cover portion, when processing the workpiece with the tip tool This prevents foreign matter such as dust scattered by the tip tool from entering the spring chamber. Accordingly, dust or the like is prevented from biting into the spring member, the holder provided with the seal member moves smoothly, and the workpiece can be processed smoothly. Furthermore, since dust or the like is prevented from entering the spring member, durability of the dust collecting adapter and the power tool can be improved.

It is sectional drawing which shows the disc grinder as a power tool in the state equipped with the dust collecting adapter. It is sectional drawing which shows the disc grinder in the state which is grinding the to-be-processed surface with a disc grinder. It is a bottom view of a disc grinder in the state where a grindstone wheel as a tip tool was removed. It is a bottom view of a disc grinder in the state where a grindstone wheel, a tool cover part, and a leaf spring were removed. It is a bottom view of the disc grinder which shows the state which set the leaf | plate spring to the spring attaching part shown by FIG. It is a bottom view of the disc grinder which shows the state which attached the leaf | plate spring set to the spring attaching part to the spring attaching part. It is a top view of the dust collection cover shown by FIG. (A) is a top view which shows the 1st and 2nd mounting tool which comprises the cover mounting tool provided in the dust collecting cover, (B) is a top view which shows the state which faced two mounting tools is there. It is a top view which shows the modification of a cover mounting tool. It is sectional drawing which shows the disc grinder with which the dust collecting cover of the modification was mounted | worn. It is a top view which shows the dust collection cover of FIG. (A) is sectional drawing which shows the surface shape of the projection part provided in the fan case part, (B) is sectional drawing which shows the modification of a projection part.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The power tool shown in FIGS. 1 to 6 is a portable or hand-held disc grinder 10. The disc grinder 10 is used, for example, to grind the surface using concrete or stone as a workpiece W. It is also called a disc sander. The disc grinder 10 has a cylindrical motor case 11a and a gear case 11b attached to the tip of the cylindrical motor case 11a. An electric motor 12 is accommodated in the motor case 11a as a power source. The electric motor 12 is connected to a commercial power source via a power cord (not shown) drawn from the rear end of the motor case 11a, and is driven by electric power supplied from the commercial power source. When electric power is supplied to the electric motor 12 from the battery, for example, the battery is attached to the rear end portion of the motor case 11a.

  A bevel gear 14 is attached to the rotating shaft 13 of the electric motor 12, and a bevel gear 15 that meshes with the bevel gear 14 is attached to a metal main body spindle 16 that is disposed at right angles to the rotating shaft 13. 12 is rotationally driven. The main body spindle 16 is rotatably supported by a bearing 17 attached to the gear case 11b. The bearing 17 is attached to the gear case 11b by an annular holding member 18 fixed to the gear case 11b. The holding member 18 is coaxial with the main body spindle 16 and is provided radially outward of the main body spindle 16. The front end of the main body spindle 16 protrudes from the front surface of the gear case 11b.

  In the disc grinder 10, the power tool main body 10a is configured by the motor case 11a, the gear case 11b, and the above-described members incorporated therein. A dust collecting adapter 20 is detachably attached to the front side of the power tool main body 10a. The dust collecting adapter 20 has a dust collecting cover 21, and a cup-type grindstone wheel 23 and a dust collecting fan 22 as a tip tool are accommodated in the dust collecting cover 21, and the dust collecting fan 22 and the grindstone are accommodated. Each of the wheels 23 is driven to rotate by the main body spindle 16.

  The dust collecting fan 22 has a cylindrical boss portion 22a, a disk portion 22b provided on the base end side of the boss portion 22a, and a plurality of blade portions 22c provided on the front side thereof. It is molded from resin. Similarly to the main body spindle 16, a metal extension spindle 24 is mounted on the boss portion 22 a, and the rotation of the main body spindle 16 is transmitted to the dust collecting fan 22 via the extension spindle 24. In order to transmit the rotation of the extension spindle 24 to the dust collecting fan 22, a flat surface (not shown) is formed on the outer peripheral surface of the extension spindle 24, and a flat surface in contact with the flat surface is formed on the boss portion 22a. Is provided. A screw hole 26 to which a male screw portion 25 provided at the distal end portion of the main body spindle 16 is screwed is provided at the base end portion of the extension spindle 24, and the extension spindle 24 projects into the step portion of the main body spindle 16. Hit. A male screw part 27 having the same outer diameter as the male screw part 25 is provided at the tip of the extension spindle 24, and a grindstone wheel 23 is attached to the male screw part 27.

  This grindstone wheel 23 has a base 23a formed in a cup shape, and a plurality of diamond grindstones 23b are fixed to the front outer periphery of the base 23a by means such as adhesion. A boss 28 is disposed on the back side of the central portion of the base plate 23a in the radial direction, and a lock nut 29 is disposed on the front side. The lock nut 29 is screwed to the male thread portion 27 of the extension spindle 24, and the grindstone wheel 23 is fastened to the extension spindle 24 by the lock nut 29.

  The dust collection adapter 20 includes a dust collection fan 22 provided with an extension spindle 24 and a dust collection cover 21 that accommodates the dust collection fan 22. The dust collection adapter 20 is detachable or removable from the power tool main body 10a.

  The disc grinder 10 shown in FIG. 1 is a dust collection type in which a dust collection adapter 20 is mounted on a power tool main body 10a. When the grindstone wheel 23 is removed from the extension spindle 24 and the dust collecting adapter 20 is detached from the power tool main body 10 a and the grindstone wheel 23 is attached to the male thread portion 25 of the main body spindle 16, the disc grinder 10 is a simple type that does not have the dust collecting adapter 20. become. The extension spindle 24 of the dust collection adapter 20 shown in FIG. 1 can be separated from the dust collection fan 22, but when the dust collection fan 22 is resin-molded, a metal extension spindle 24 is placed in the mold. When the extension spindle 24 is insert-molded together with the dust collecting fan 22 after being arranged, the dust collecting fan 22 is in a form in which the extension spindle 24 is fixed. Further, when the extension spindle 24 is made of resin in the same manner as the dust collection fan 22 and is resin-molded, the dust collection fan 22 is formed by integrally forming the extension spindle 24 and the dust collection fan 22.

  An engagement recess 31 made of a hexagonal hole is formed on the distal end surface of the extension spindle 24, and a plurality of engagement recesses 32 are formed in the lock nut 29 at intervals in the circumferential direction. When removing the grindstone wheel 23 from the power tool main body 10a to which the dust collecting adapter 20 is attached, an attachment / detachment jig (not shown) is engaged with one engagement recess 31 and another attachment / detachment treatment is performed with the other engagement recess 32. Under the state where the tool is engaged, while the rotation of the extension spindle 24 is restricted by one attachment / detachment jig, the lock nut 29 is rotated in the loosening direction by the other attachment / detachment jig. Accordingly, the lock nut 29 can be easily detached from the external thread portion 27 of the extension spindle 24 without rotating the extension spindle 24 with respect to the main body spindle 16.

  On the other hand, when the extension spindle 24 is attached to the main body spindle 16, it is necessary to regulate the rotation of the main body spindle 16, and in order to regulate the rotation of the main body spindle 16, a lock button 33 is provided on the gear case 11b. . The lock button 33 is provided with a lock pin (not shown) that can reciprocate in a direction parallel to the main body spindle 16. When the lock button 33 is pushed in, the lock pin engages with a recess (not shown) formed in the bevel gear 15. The bevel gear 15 is fixed and the rotation of the main body spindle 16 is restricted. The extension spindle 24 can be screwed to the main body spindle 16 by rotating the extension spindle 24 in a state where the rotation of the main body spindle 16 is restricted. The lock button 33 restricts the rotation of the main body spindle 16 when the extension spindle 24 is removed from the main body spindle 16 and when the grindstone wheel 23 is screwed to the main body spindle 16 or the screw is loosened.

  The disc grinder 10 shown in FIG. 1 can be set to the simple type and the dust collection type described above, but as the dust collection type exclusive type disc grinder 10, a main spindle having a long dimension including the extension spindle 24 is used. 16 will be attached to the power tool main body 10a.

  The dust collecting cover 21 has a fan case portion 34 that accommodates the dust collecting fan 22, and the fan case portion 34 includes first and second case halves 34 a and 34 b formed of a resin material such as nylon, respectively. The fan housing chamber 35 is formed inside the fan case 34 by assembling. The first case half 34a has an end wall portion 36 attached to the power tool main body 10a and a cylindrical peripheral wall portion 37 integrated on the front side thereof. The second case half 34 b has a cylindrical peripheral wall portion 38 that abuts against the peripheral wall portion 37 and a partition wall portion 39 that is integrated with the front side of the second peripheral half portion 34 b and faces the end wall portion 36. The partition wall 39 protrudes radially inward from the peripheral wall 38, the rear side of the partition wall 39 faces the radial outer periphery of the dust collecting fan 22, and the radially inner end of the partition wall 39 Is formed with a suction port 39a.

  When the dust collecting fan 22 is rotated by the electric motor 12, air flows into the fan housing chamber 35 from the outside through the suction port 39a. The rotation direction of the dust collecting fan 22 is a direction indicated by an arrow R in FIG. The volute flow path formed between the fan case portion 34 and the outer periphery of the dust collection fan 22 has a cross-sectional area that gradually increases toward the downstream side in the circumferential direction. As shown in FIGS. 3 and 4, a discharge duct 40 is provided in the fan case portion 34 so as to communicate with the most downstream of the volute flow path. The discharge duct 40 is formed by abutting a duct piece 40a integrated with the first case half 34a and a duct piece 40b integrated with the second case half 34b. A dust collection bag (not shown) is attached.

  A cylindrical tool cover portion 41 is attached to the front end surface of the fan case portion 34, and the dust cover 21 is configured by the tool cover portion 41 and the fan case portion 34. As shown in FIG. 3, the tool cover portion 41 is attached to the fan case portion 34 by a screw member 43 attached to a bracket 42 that protrudes radially outward from the tool cover portion 41. As shown in FIG. 4, the fan case portion 34 is provided with a mounting hole 44 to which the screw member 43 is screwed.

  An annular holder 45 is mounted in the tool cover 41 so as to be movable in the axial direction, that is, in the axial direction of the extension spindle 24, and the holder 45 has a radial outer side of the grinding wheel 23 as a tip tool. A seal member 46 is attached in an annular shape so as to cover it. The seal member 46 is made of felt and is also called a skirt member. As shown in FIGS. 1 and 2, a spring chamber 47 is formed between the holder 45 and the front surface of the fan case portion 34, and four leaf springs 48 are arranged in the spring chamber 47. Yes. A spring force toward the front of the dust collecting cover 21 is urged to the holder 45 by the leaf spring 48. In order to restrict the forward protrusion of the holder 45, as shown in FIGS. 1 and 2, the holder 45 is provided with a protrusion 45a protruding outward in the radial direction, and a stopper 41a contacting the protrusion 45a is provided as a tool. The cover portion 41 is provided at the distal end portion so as to protrude radially inward. When the grinding wheel 23 is pressed against the workpiece W to grind the workpiece W such as concrete, as shown in FIG. 2, the seal wheel 46 is pressed against the workpiece W as shown in FIG. 2. Thus, it is possible to prevent the dust from being blown out.

  In order to fix each leaf spring 48 to the fan case portion 34, as shown in FIG. 4, a spring attachment portion 49 to which an end portion of the leaf spring 48 is attached is provided on the front surface of the fan case portion 34. Each of the leaf springs 48 has a flat arc shape along the inner peripheral surface of the cylindrical or annular tool cover portion 41. When the leaf spring 48 is attached to the spring attachment portion 49, it is shown in FIG. The leaf spring 48 is set inside the tool cover portion 41 so as to be Under this state, when the leaf spring 48 is inserted into a slit (not shown) formed in the spring mounting portion 49, a protrusion 49 a provided on the spring mounting portion 49 is attached to an attachment hole 48 a provided on the end portion of the leaf spring 48. The leaf spring 48 is fixed to the spring mounting portion 49 by being inserted therein. FIG. 6 shows a state in which the leaf spring 48 is attached to the spring attachment portion 49. When the tool cover portion 41 in which the holder 45 is incorporated is fixed to the fan case portion 34 by the screw member 43 with the leaf spring 48 attached, the dust collection cover 21 is assembled as shown in FIG.

  As shown in FIG. 1 and FIG. 2, a shield wall 51 that protrudes in the axial direction toward the fan case portion 34 is provided in an annular shape on the inner periphery of the holder 45. It is a shielding wall on the movable side that moves in the axial direction. On the other hand, a fixed-side shielding wall 52 that projects in the axial direction toward the front is provided in an annular shape on the front surface of the fan case portion 34. The outer diameter of the fixed-side shielding wall 52 is smaller than the inner diameter of the movable-side shielding wall 51, and the spring chamber 47 is defined by both the shielding walls 51, 52 and the tool cover portion 41.

  As shown in FIG. 2, when the seal member 46 is pressed against the workpiece W during the grinding process and the holder 45 and the seal member 46 move toward the fan case portion 34, the movable shielding wall 51 is fixed to the fixed side. It is in a state where it overlaps the outside of the shielding wall 52 with a slight gap, that is, it overlaps. As a result, the spring chamber 47 is shielded from the grindstone wheel 23, so that dust and fine particles scattered during grinding are prevented from entering the spring chamber 47. When intrusion of dust or the like into the spring chamber 47 is prevented, the dust is not digged into the leaf spring 48. The number of leaf springs 48 is not limited to four and can be any number. Further, the spring member is not limited to a leaf spring, and a compression coil spring may be used.

  The dust collecting adapter 20 shown in the figure has a configuration in which shielding walls 51 and 52 are provided on both the holder 45 and the fan case portion 34. However, dust or the like can be prevented from entering the spring chamber 47 during the grinding process. If so, a shielding wall may be provided only on at least one of the holder 45 and the fan case portion 34. In that case, a single shielding wall form having one shielding wall is obtained. If the inner diameter of the fixed-side shielding wall 52 is made larger than the outer diameter of the movable-side shielding wall 51 by reversing the magnitude relationship between the diameters of both the shielding walls 51, 52, the movable-side shielding wall 51 is movable during grinding. The shielding wall 51 is overlapped with the inside of the shielding wall 52.

  A tapered surface 53 whose inner diameter decreases from the front side to the rear side is formed on the inner peripheral side of the tip surface of the holder 45, and the flow of suction air generated by the dust collecting fan 22 is formed on the tapered surface 53. Are provided at equal intervals in the circumferential direction. By providing the tapered surface 53 on the holder 45, the suction air is smoothly guided toward the suction port 39 a of the fan case portion 34, and flows to the suction port 39 a while turning by providing the rib 54 on the tapered surface 53. The suction air can be guided more smoothly.

  On the front surface of the partition wall portion 39 constituting the fan case portion 34, when a relatively large foreign matter such as a concrete piece is scattered toward the suction port 39a during the grinding operation, the foreign matter enters the fan accommodating chamber 35. In order to prevent this, a protector 55 is provided. As shown in FIGS. 3 to 6, the protector 55 includes a ring portion 55 a having a smaller diameter than the inner diameter of the suction port 39 a and a radially outer end integrated with the partition wall portion 39 and a radially inner end. Has a plurality of ribs or leg portions 55b integrated with the ring portion 55a. Each leg 55b is curved so that the inner end is inclined toward the rotational direction of the dust collecting fan 22 in the direction along the suction air flow direction corresponding to the rib 54, and the outer end is inclined toward the rotational direction of the dust collecting fan 22. The suction air can be guided more smoothly and the flow can be rectified. The protector 55 is integrally formed when the partition wall 39 is resin-molded, and the protector 55 having a rectifying function and a foreign substance intrusion preventing function can be manufactured at a low cost. Furthermore, since the plurality of leg portions 55b are connected to the ring portion 55a, the durability and reliability of the dust collecting cover 21 can be enhanced by the protector 55. As shown in FIG. 3, twelve ribs 54 are provided on the tapered surface 53, and twelve leg portions 55 b of the protector 55 are provided corresponding to the ribs 54. However, the number of each is not limited to the illustrated form.

  When the surface of the workpiece W is ground by the disc grinder 10 to which the dust collecting cover 21 is attached, the outer side in the radial direction of the grinding wheel 23 is covered by the seal member 46 and the grinding surface of the grinding wheel 23 is The back side that is the opposite side is covered with the partition wall 39 and the protector 55. When the electric motor 12 is operated, the dust collecting fan 22 rotates together with the grindstone wheel 23 and generates a suction force at the suction port 39a. When the grinding wheel 23 is pressed against the workpiece W such as concrete or tile and grinding is performed, dust such as grinding powder scatters radially outward from the outer periphery of the grinding wheel 23. The scattered dust is blocked from leaking to the outside by the seal member 46 and guided to the inside of the holder 45. The dust guided to the inside of the holder 45 is sucked into the fan housing chamber 35 from the suction port 39a by the suction force of the dust collecting fan 22, and is discharged from the discharge duct 40 through the volute channel. The discharged dust is collected in a dust collection bag (not shown) provided at the end of the discharge duct 40.

  Dust generated by grinding by the grinding wheel 23 is scattered in a tangential direction from the outer peripheral portion of the grinding wheel 23 and passes between the outer peripheral portion of the grinding wheel 23 and the holder 45 while turning inside the holder 45. Suction toward the suction port 39a. At this time, the tapered surface 53 of the holder 45 is provided with ribs 54 that follow the flow of dust and are inclined with respect to the circumferential direction, so that the dust is guided by the ribs 54 and swivels in the same direction as the grinding wheel 23. However, it flows toward the suction port 39a. The flow of dust that has passed between the outer peripheral portion of the grinding wheel 23 and the holder 45 passes through the inside of the shielding wall 52 toward the suction port 39a, and does not enter the spring chamber 47. It is possible to reliably prevent foreign matter from getting into 48. Thereby, the durability of the disc grinder 10 can be improved.

  In order to mount the dust collecting cover 21 on the cover mounting portion using the holding member 18 of the power tool main body 10a as the cover mounting portion, as shown in FIG. A tool 60 is provided. As shown in FIGS. 7 and 8, the cover mounting tool 60 includes a first mounting tool 61 and a second mounting tool 62 screwed to the first mounting tool 61. The first mounting tool 61 has an arc-shaped fastening band portion 61a fastened to the cover mounting portion of the power tool main body 10a, and a fixing plate 61b fixed to the fan case portion 34 by four screw members 63. These are united. As shown in FIG. 8, the fixing plate 61b is formed with a mounting hole 63a through which the screw member 63 passes. The second mounting tool 62 has an arc-shaped fastening band portion 62a that is fastened to the cover mounting portion, and a butting plate 62b that is abutted against the fan case portion 34, and these are integrated. The dust collection cover 21 is mounted by fastening both ends of the fastening bands 61 a and 62 a with the screw members 64. 8A shows a state in which the second mounting tool 62 is opposed to the first mounting tool 61, and FIG. 8B shows a state in which both the mounting tools 61 and 62 are abutted.

  The fan case portion 34 is provided with a projection 65 at a portion facing the motor case 11 a toward the motor case 11 a, and the fixing plate 61 b is abutted against the projection 65. When the operator grips the motor case 11a and presses the grindstone wheel 23 against the workpiece W during grinding, a pressing force is applied to the dust collecting cover 21 in the counterclockwise direction in FIG. Each of the mounting tools 61 and 62 is formed by bending a metal plate member. When a pressing force is applied to the dust collecting adapter 20 during the grinding process, the mounting tools 61 and 62 are elastically deformed. Become. When the mounting devices 61 and 62 are repeatedly elastically deformed, the durability thereof is lowered. However, since the protrusion 65 protrudes toward the motor case 11 a toward the fan case 34, the motor case 11 a becomes the protrusion 65. By abutting, the amount of elastic deformation of the wearing tools 61 and 62 is limited, and the durability of the wearing tools 61 and 62 can be improved. When no pressing force is applied to the dust collection adapter 20, a gap G is formed between the protrusion 65 and the motor case 11a.

  FIG. 9 is a plan view showing a modification of the cover mounting tool. The protrusion 65 shown in FIG. 9 is curved in the circumferential direction of the dust collection cover 21. Thereby, even if the attachment attitude | position to the power tool main body 10a of the dust collection cover 21 shift | deviates, the projection part 65 can be made to contact | abut to the motor case 11a reliably. 7 and 9 show a state in which the dust collection bag 67 is attached to the discharge duct 40. FIG.

  The dust collecting cover 21 shown in FIGS. 10 and 11 is different from the case where the cover mounting tool 60 for mounting on the power tool main body 10a is described above. The first mounting tool 61 includes a fastening band portion 61a and three fixing pieces 61c that extend integrally with the fastening band portion 61a. The 2nd mounting tool 62 is formed only by the fastening belt | band | zone part 62a, and the butting plate 62b is not provided. Since the cover mounting tool 60 having such a configuration is more easily elastically deformed than the cover mounting tool shown in FIGS. 7 to 9, the protruding length of the protrusion 65 is set to be longer than that shown in FIG. The gap G between the protrusion 65 and the gear case 11b is narrower than that described above. Thereby, even if a pressing force is applied to the dust collecting adapter 20 during grinding, the durability of the mounting tools 61 and 62 can be improved without the elastic deformation of the mounting tools 61 and 62.

  FIG. 12A is a cross-sectional view showing the shape of the tip surface of the projection 65 shown in FIG. 7, and the tip surface 66 of the projection 65 is flat. On the other hand, the front end surface 66 of the protrusion 65 shown in FIG. 12B is a concave arcuate surface corresponding to the outer peripheral surface of the motor case 11a. As described above, when the tip surface 66 is an arc surface corresponding to the outer peripheral surface of the motor case 11a, the entire tip surface of the protruding portion 65 comes into contact with the outer peripheral surface of the motor case 11a. Can be dispersed, and the risk of breakage of the protrusion 65 due to load concentration can be reduced. 7 to 12, members that are the same as those shown in FIGS. 1 to 6 are assigned the same reference numerals, and duplicate descriptions are omitted.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, although the illustrated disc grinder 10 is an electric tool, that is, a power tool using an electric motor as a drive source, the present invention can be applied to a power tool using an air motor as a drive source. The illustrated disc grinder 10 is used for grinding the surface of the workpiece, and can rough the surface of the workpiece by grinding. On the other hand, finishing is said to be polishing, and a power tool for polishing is called a disk sander or a polisher. The power tool of the present invention can also be applied to a tool for polishing.

DESCRIPTION OF SYMBOLS 10 ... Disc grinder, 10a ... Power tool main body, 11a ... Motor case, 11b ... Gear case, 12 ... Electric motor, 13 ... Rotating shaft, 14, 15 ... Bevel gear, 16 ... Main body spindle, 17 ... Bearing, 18 ... Holding member ( Cover mounting part), 20 ... dust collecting adapter, 21 ... dust collecting cover, 22 ... dust collecting fan, 23 ... grinding wheel, 24 ... extension spindle, 25 ... male screw part, 26 ... screw hole, 27 ... male screw part, 28 ... Boss, 29 ... Lock nut, 31 ... Engagement recess, 32 ... Engagement recess, 33 ... Lock button, 34 ... Fan case part, 35 ... Fan housing chamber, 36 ... End wall part, 37, 38 ... Peripheral wall part, 39 ... partition wall part, 40 ... discharge duct, 41 ... tool cover part, 42 ... bracket, 43 ... screw member, 44 ... mounting hole, 45 ... holder, 46 ... seal member, 47 ... spring 48 ... leaf spring, 49 ... spring mounting portion, 51, 52 ... shielding wall, 53 ... taper surface, 54 ... rib, 55 ... protector, 55a ... ring portion, 55b ... leg portion, 60 ... cover fitting, 61, 62 ... Wearing tool, 63, 64 ... Screw member, 65 ... Projection, 66 ... Tip surface.

Claims (6)

A dust collecting adapter that collects dust generated when a workpiece is processed by a tip tool rotated by a main body spindle of a power tool body,
A dust collecting fan rotated by the main body spindle;
A fan case portion mounted on the main body of the power tool and housing the dust collecting fan, and an annular holder provided on the front surface of the fan case portion and mounted with a seal member that covers the outside of the tip tool is movable. A dust cover with a tool cover for guiding;
A spring member disposed in a spring chamber formed between the holder and the front surface of the fan case portion, and biasing the holder forward;
A dust collecting adapter, comprising: an annular shielding wall provided on at least one of the front surface of the fan case portion and the back surface of the holder and defining the spring chamber by the tool cover portion.   A fixed-side shielding wall provided on a front surface of the fan case portion; and a movable-side shielding wall provided on a back surface of the holder, and the movable side when the holder moves toward the fan case portion. The dust collecting adapter according to claim 1, wherein the shielding wall and the stationary shielding wall overlap in a radial direction.   The outer diameter of the fixed-side shielding wall is smaller than the inner diameter of the movable-side shielding wall, and the movable-side shielding wall shields the fixed-side shielding when the holder moves toward the fan case portion. The dust collecting adapter according to claim 2, wherein the dust collecting adapter overlaps the outside of the wall.   The dust collection adapter according to any one of claims 1 to 3, wherein the spring member disposed in the spring chamber is a leaf spring.   The inner peripheral surface of the holder is a tapered surface whose inner diameter decreases from the front side toward the back side, and a plurality of ribs are provided on the tapered surface in a direction along the flow of suction air generated by the dust collecting fan. The dust collection adapter according to any one of claims 1 to 4, wherein A power tool body provided with a body spindle for rotationally driving the tip tool;
A cover mounting portion provided in the power tool body;
A power tool comprising the dust collection cover according to claim 1, which is attached to the cover attachment portion.

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