JP5764990B2 - Dust collecting cover and disc grinder with dust collecting cover - Google Patents

Description

  The present invention relates to a portable disc grinder used for surface grinding work of a work material and a dust collecting cover that is attached to the grinder and collects dust such as grinding powder generated during grinding work.

  A portable disk grinder equipped with a disk-shaped (wheel-shaped) tip tool is often used for a surface grinding operation for flatly grinding the surface of a work material such as concrete or stone.

  The disc grinder includes a cylindrical case that houses a drive source such as an electric motor or an air motor, and a cylindrical boss portion is provided on the tip side of the case so as to be orthogonal to the axial direction of the case. . A spindle serving as an output shaft of the disc grinder projects from the boss portion, and a tip tool is attached to the tip of the spindle. The spindle is connected to a drive source via a gear mechanism, and when the drive source is activated, the tip tool is rotationally driven by the drive source together with the spindle.

  The disc grinder is provided with a dust collection cover, also called a dust collection adapter, in order to prevent scattering of dust such as grinding powder generated during grinding operation.

  The dust collection cover is formed in a bottomed cylindrical shape (cup shape) including a cylindrical peripheral wall that covers the outer periphery of the tip tool and a top wall that covers the back side of the tip tool, and is provided on the top wall. The mounting portion is detachably mounted on the boss portion of the disc grinder. The dust collection cover is provided with a suction duct, and this suction duct is connected to the dust collector by a flexible hose such as rubber. Thereby, the dust generated at the time of grinding work is collected by the dust collector through the suction duct and the hose without being scattered from the dust collection cover to the outside (see, for example, Patent Document 1).

  On the other hand, as a dust collecting cover, a self dust collecting type has been developed in which the dust collecting cover itself has a dust collecting function without using a dust collecting device. The dust collection cover of the self-dust collection type is equipped with a centrifugal fan inside the cup-shaped cover body of the dust collection cover, and this centrifugal fan is fixed to the spindle between the tip tool and the boss part together with the tip tool. Rotate. When the centrifugal fan rotates, dust inside the cover main body is collected by a dust collecting bag attached to the discharge duct by the suction force.

JP 2009-23005 A

  Such a dust collection cover of the self-dust collection type is formed in a cylindrical shape with a bottom that covers the outer periphery of the disk-shaped tip tool over the entire circumference. It is necessary to work with the dust cover removed and only the tip tool attached to the spindle.

  In the conventional structure, the work to remove the dust cover from the disc grinder is to first remove the tip tool and the centrifugal fan sequentially from the spindle, then remove the case body from the boss, and then attach the tip tool to the tip of the spindle. ing. When the dust collecting cover is attached to the disc grinder again, the reverse procedure to the above is performed.

  As described above, in the conventional dust collecting cover, it is necessary to remove the cover main body, the centrifugal fan, and the tip tool individually for attaching and detaching to and from the disc grinder, and the work is complicated.

  An object of the present invention is to facilitate the attaching / detaching operation of the dust collecting cover to the portable disc grinder.

A dust collection cover according to the present invention is a dust collection cover attached to a portable disc grinder capable of attaching a tip tool to a spindle, and has an attachment portion attachable to the disc grinder, and a side opposite to the attachment portion. A cylindrical cover portion that is provided on the facing axial end surface and covers the outer periphery of the tip tool, and a volute channel that continues to the discharge port, is fixed to the disc grinder with the suction port facing the tip tool side. A volute case part, a centrifugal fan housed in the volute case part and attached to the spindle between the tip tool and the attachment part; and the centrifugal fan when the volute case part is removed from the disc grinder and a first positioning means for positioning inside in the radial direction of the volute casing portion, the centrifugal fan Characterized in that the remains the volute casing portion of the accommodated state is detachable to the disk grinder.

The first positioning means includes a circular concave portion provided on an inner surface facing the axial direction of the volute case portion, and a disk-shaped substrate provided on the centrifugal fan and disposed in the circular concave portion. .

More specifically, the first positioning means includes a circular recess provided in an inner surface of the volute channel and facing an axial direction of the volute case portion, and a circular recess provided in the centrifugal fan. by the disk-shaped substrate which is disposed in a recess made Ri構.

In one aspect of the present invention, there is provided second positioning means for positioning the centrifugal fan in the radial direction inside the volute case when the volute case is removed from the disc grinder. The second positioning means is provided on an annular inclined surface provided on the inner surface of the volute case portion facing in the axial direction so as to be inclined with respect to the axial direction, and on an end surface facing the inclined surface of the centrifugal fan. It made Ri構 by the the inclined side portion inclined to the inclined face in the same direction Te.

In another aspect of the present invention, the first positioning means and the second positioning means are respectively provided on both axial sides of the centrifugal fan .

In another aspect of the present invention, the attachment portion includes a fixing means that can be attached to the disc grinder, and the fixing means can be manually operated from the outside .

In another aspect of the present invention, the attachment portion, the volute provided in the case portion, and the first adapter semi-cylindrical for engaging the outer peripheral surface of the ball scan unit, a separate body from the first adapter A second adapter that is formed in a semi-cylindrical shape and is combined with the first adapter across the boss portion, a connecting member that connects one end side of the first adapter and the second adapter, the first adapter, and the A cam mechanism that connects the other end of the second adapter and that can be driven in a direction that narrows the gap between the other adapters; and a lock arm that operates the cam mechanism. The first adapter and the second adapter are the bosses. When the locking arm is in a fixed state, the entire length of the lock arm is arranged along the outer surface of the volute case .

  A disc grinder according to the present invention includes a housing that houses an electric motor, a spindle that extends from the housing and is fitted with a tip tool, a mounted portion that is disposed around the spindle, and a mounting portion that is attached to the mounted portion. The dust collection cover covering the tip tool is provided.

  According to the present invention, the centrifugal fan is housed in the volute case portion and is positioned in the radial direction inside the volute case portion by the positioning means even when it is detached from the disc grinder, so that the dust collecting cover is attached to the disc grinder. At this time, by fixing the volute case part to the boss part, the centrifugal fan can be mounted on the spindle without adjusting its radial position. Further, when removing the dust collecting cover from the disc grinder, the centrifugal fan can be removed from the spindle together with the case by removing the volute case part from the boss part. Thus, since the dust collecting cover can be attached to and detached from the disc grinder using the volute case portion and the centrifugal fan as one unit, the attaching and detaching work of the dust collecting cover to the disc grinder can be facilitated.

  According to the present invention, by disposing a convex portion provided coaxially with the concave portion on either one of the volute case portion and the centrifugal fan in the concave portion provided on either the volute case portion or the centrifugal fan, the centrifugal fan is Since the volute case portion is positioned in the radial direction, the positioning means can have a simple configuration.

  According to the present invention, the centrifugal fan is positioned in the radial direction inside the volute case portion by the structure in which the disc-shaped substrate provided in the centrifugal fan is disposed in the circular concave portion provided in the inner surface facing the axial direction of the volute case portion. Thus, the volume of the portion of the volute case portion that supports the load applied from the centrifugal fan can be increased to increase the strength and durability of the positioning means.

  According to the present invention, the centrifugal fan is mounted on the volute case by the structure in which the inclined side portion of the centrifugal fan is opposed to the annular inclined surface provided on the inner surface facing the axial direction of the volute case portion. Since the positioning is performed in the radial direction inside the section, the positioning means is configured with a simple configuration using the inclined side portions provided to make each passage cross-sectional area constant in each blade of the centrifugal fan. Can do.

  According to the present invention, the volute case portion can be fixed to the boss portion by the operation of the lock arm, and the fixation can be released. Therefore, the volute case portion can be attached to and detached from the boss portion by a simple operation. In addition, when the volute case part is fixed to the boss part, the entire longitudinal direction of the lock arm is arranged along the outer surface of the volute case part. Even if it is used, this lock arm can be prevented from interfering with work.

It is a partially cutaway sectional view of a disk grinder which is one embodiment of the present invention. It is sectional drawing which shows the structure of the dust collecting cover shown in FIG. It is a top view which shows the inside of the 1st case half body of the dust collecting cover shown in FIG. It is a perspective view which shows the detail of the attaching part shown in FIG. 1, (a) is a perspective view which shows the state before fixation, (b) is a perspective view which shows the state after fixation. It is a modification of the dust collecting cover shown in FIG. 2, Comprising: It is sectional drawing which shows the structure which has arrange | positioned the cylindrical convex part provided in the centrifugal fan in the annular recessed part provided in the inner surface of the volute case part.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  A portable (hand-held) disc grinder 11 shown in FIG. 1 is also called a disc sander, and is used for a surface grinding operation in which the surface of a work material such as concrete or stone is ground flat.

  The disc grinder 11 includes a main body case 13 formed in a cylindrical shape, and an electric motor 14 is accommodated in the main body case 13. The electric motor 14 is connected to a commercial power source (not shown) via a power cord 15 drawn from the rear end of the main body case 13 and is operated by electric power supplied from the commercial power source.

  A gear case 16 is attached to the front end portion of the main body case 13, and the main body case 13 and the gear case 16 constitute a housing of the disc grinder 11.

  The gear case 16 includes a cylindrical boss portion 16 a orthogonal to the axial direction of the main body case 13, and a spindle 17 is provided on the gear case 16 so as to be rotatably supported by the boss portion 16 a. The spindle 17 is disposed coaxially with the boss portion 16 a, and a tip portion of the spindle 17 protrudes from the boss portion 16 a toward the outside of the gear case 16. A pair of bevel gears 18 a and 18 b are accommodated in the gear case 16, and the rotation of the electric motor 14 is transmitted to the spindle 17 by changing the direction of 90 degrees by these bevel gears 18 a and 18 b.

  A diamond grinding wheel 19 as a disk-shaped (wheel-shaped) tip tool is attached to the tip of the spindle 17. The diamond wheel 19 includes a substrate 19a formed in a cup shape from a steel plate, and a plurality of diamond wheels 19b arranged in a plane are fixed to the surface of the substrate 19a by means such as adhesion. . The diamond grindstone wheel 19 is attached to the tip of the spindle 17 at the axis of the substrate 19a, and is fixed by being sandwiched between a washer 21 attached to the spindle 17 and a nut 22 screwed to the tip of the spindle 17. Has been. Further, the diamond grinding wheel 19 can be removed from the spindle 17 by removing the nut 22.

  When a power switch (not shown) provided on the main body case 13 is turned on, electric power is supplied to the electric motor 14, and the diamond grindstone wheel 19 is driven by the electric motor 14 and rotates together with the spindle 17. By uniformly pressing the entire surface of the rotated diamond grinding wheel 19 against the surface of the work material and moving it back and forth and left and right, a surface grinding operation for grinding the surface of the work material flat can be performed.

  In the present embodiment, the diamond grindstone wheel 19 is used as a disk-shaped tip tool. However, the present invention is not limited thereto, and the entire surface of the workpiece is pressed against the surface of the work material. As long as the tool can grind the surface flatly, other tip tools such as a sanding disk may be used.

  A dust collecting cover 31 is detachably attached to the disc grinder 11 in order to prevent dust such as grinding powder generated by the grinding operation from scattering. The dust collection cover 31 is also called a dust collection adapter, and is a self-dust collection type in which dust is forcibly collected by the centrifugal fan 32 to the dust collection bag 33.

  The dust collecting cover 31 includes a volute case portion 34 formed of a resin material such as nylon. The volute case 34 is disposed between the disc grinder 11 and the diamond grinding wheel 19 when the dust collection cover 31 is attached to the disc grinder 11.

  As shown in FIG. 2, the volute case portion 34 is formed by combining a first case half 34 a and a second case half 34 b formed in a cup shape in the axial direction so that the open ends thereof are butted, not shown. It is comprised by mutually fastening by fastening means, such as a volt | bolt. That is, the volute case part 34 can be divided in the axial direction.

  The volute case 34 includes a peripheral wall 35 formed in a substantially cylindrical shape having a larger diameter than the diamond grinding wheel 19, a top wall 36 and a bottom wall 37 formed in a substantially disk shape perpendicular to the axial direction of the spindle 17. It has. A fan housing chamber 38 is provided as a cylindrical space inside the volute case portion 34, and a volute channel 39 is provided on the outer peripheral side of the fan housing chamber 38. The volute channel 39 is formed in a shape in which the radial dimension and the axial dimension gradually expand toward the circumferential direction, that is, the passage area gradually increases. The downstream end of the volute channel 39 is connected to a discharge duct 41 as a discharge port provided on the peripheral wall 35 of the volute case 34. The discharge duct 41 is formed in a cylindrical shape protruding in the tangential direction from the peripheral wall 35, and the above-described dust collection bag 33 is attached to the tip thereof.

  An attachment portion 42 is provided on the top wall 36 of the volute case portion 34 in order to fix the volute case portion 34 to a boss portion 16 a as an attachment portion disposed around the spindle 17 of the disc grinder 11. The dust collecting cover 31 is attached to the disc grinder 11 by attaching the attachment portion 42 to the boss portion 16a.

  As shown in FIG. 4, the mounting portion 42 includes a semi-cylindrical first adapter 42a having the same inner diameter as the outer diameter of the boss 16a, and a half having the same inner diameter as the outer diameter of the boss 16a. A second adapter 42b formed in a cylindrical shape and combined with the first adapter 42a is provided. The first adapter 42a is formed integrally with the top wall 36, and the second adapter 42b is formed of a resin material separately from the first adapter 42a. The first adapter 42a engages with the outer peripheral surface of the boss portion 16a on its inner peripheral surface, and the second adapter 42b engages with the outer peripheral surface of the boss portion 16a on the inner peripheral surface from the side opposite to the first adapter 42a. . One end of the first adapter 42a is connected to one end of the second adapter 42b by a bolt 43a and a nut 43b as connecting members, and the other end of the first adapter 42a is connected to the other end of the second adapter 42b by a bolt 44a and a nut 44b. It is connected by.

  A bolt 44a that connects the other end of the first adapter 42a to the other end of the second adapter 42b is provided with a cam mechanism 45 as a fixing means. The cam mechanism 45 has a cam 45a pin-coupled to a bolt 44a, and a lock arm 46 for rotating the cam 45a is fixed to the cam 45a. When the lock arm 46 is operated in the locking direction with the mounting portion 42 fitted in the boss portion 16a, that is, with the boss portion 16a disposed between the adapters 42a and 42b, the second adapter 42b is moved to the first adapter by the cam 45a. The first adapter 42a and the second adapter 42b are driven in the direction of narrowing each other's distance by being pressed in the direction 42a. Thereby, the boss portion 16a is sandwiched between the first adapter 42a and the second adapter 42b, and the attachment portion 42 is fixed to the boss portion 16a. On the other hand, when the lock arm 46 is operated in the release direction, the pressing of the first adapter 42a and the second adapter 42b by the cam 45a is released, and the attachment portion 42 is brought into an unfixed state that can be attached to and detached from the boss portion 16a.

  The lock arm 46 is formed in a long bar shape from a steel plate or the like, and its tip is bent at a right angle to form a locking portion 46a. When the cam mechanism 45 is in a non-fixed state where the boss portion 16a is not clamped, the lock arm 46 has a half on the front end side in the longitudinal direction, and the outer surface of the top wall 36 of the volute case portion 34, as shown in FIG. Projecting outward from This facilitates the operation using the distal end side of the lock arm 46.

  On the other hand, when the lock arm 46 is operated in the lock direction and the cam mechanism 45 is fixed so as to sandwich the boss portion 16a, the lock arm 46 is entirely voluteed as shown in FIG. 4B. It arrange | positions along the outer surface of the top wall 36 of the case part 34, and will be in the state which the latching | locking part 46a of the front-end | tip engaged with the surrounding wall 35 of the volute case part 34. FIG. Thereby, the lock arm 46 does not protrude from the volute case portion 34 during work, that is, the lock arm 46 can be prevented from interfering with work. Further, the engaging portion 46 a engages the peripheral wall 35 of the volute case portion 34, so that excessive rotation of the lock arm 46 can be prevented and the cam mechanism 45 can be protected.

  In this way, in the present invention, the attachment portion 42 can be easily attached to and detached from the boss portion 16a by manually operating the lock arm 46 from the outside, so that the dust collecting cover 31 can be attached to and detached from the disc grinder 11. Work can be facilitated. Further, when the volute case part 34 is fixed to the boss part 16a, the entire longitudinal direction of the lock arm 46 is arranged along the outer surface of the volute case part 34 and does not interfere with the operation. A long lock arm 46 can be used for improvement.

  The outer peripheral surface of the boss portion 16a and the inner peripheral surface of each adapter 42a, 42b are each slightly larger in outer diameter on the distal end side (side from which the spindle 17 protrudes) than on the proximal end. It is formed in a taper shape. Thereby, the volute case part 34 can be reliably fixed to the boss | hub part 16a so that each adapter 42a, 42b may not be easily removed from the boss | hub part 16a.

  The centrifugal fan (dust collecting fan) 32 is accommodated in a fan accommodating chamber 38 provided in the volute case 34.

  The centrifugal fan 32 is made of a resin material, and is a sirocco fan in which a plurality of forward blades 32a whose both ends in the radial direction are curved toward the front in the rotational direction are arranged radially on the circular substrate 32b. Yes. The axial center of the centrifugal fan 32 is provided with a two-sided mounting hole 32c, and the centrifugal fan 32 is fixed to the spindle 17 in the mounting hole 32c as shown in FIG.

  Each blade 32a of the centrifugal fan 32 is formed in a shape in which an end surface facing a side opposite to the substrate 32b in a predetermined range on the tip side thereof is inclined so that a height dimension from the substrate 32b becomes lower toward the tip side. The inclined end surface portion is an inclined side portion 32d. By providing each blade 32a with the inclined side portion 32d, the cross-sectional area between the adjacent blades 32a is set to be nearly constant. Thereby, the pressure fluctuation of the air passing between the blades 32a of the centrifugal fan 32 during rotation can be reduced, and the noise of the centrifugal fan 32 can be reduced.

  A circular through hole 47 through which the spindle 17 is inserted coaxially with the fan housing chamber 38 is provided in an inner portion of the mounting portion 42 of the top wall 36 of the volute case portion 34. A circular suction port 48 is provided coaxially with the fan housing chamber 38 on the bottom wall 37 facing the opposite side of the boss portion 16a of the volute case portion 34, that is, toward the diamond grinding wheel 19 side. Both the through hole 47 and the suction port 48 are formed to have a smaller diameter than the centrifugal fan 32 so that the centrifugal fan 32 housed in the volute case portion 34 does not fall out of the through hole 47 or the suction port 48. Has been. As described above, the centrifugal fan 32 is housed in the volute case portion 34 so as not to be detachable. That is, the volute case portion 34 and the centrifugal fan 32 are configured as one unit.

  The centrifugal fan 32 is disposed between the first case half 34a and the second case half 34b, and the case half 34a and 34b are assembled so as not to be detachable inside the volute case 34. Is done.

  A cover portion 51 is integrally provided on a bottom surface portion of the bottom wall 37 which is an axial end surface facing the diamond grindstone wheel 19 side of the volute case portion 34.

  The cover 51 is formed in a cylindrical shape having a diameter larger than that of the diamond grindstone wheel 19 and is disposed coaxially with the fan housing chamber 38. When the volute case part 34 is fixed to the boss part 16 a, the tip of the spindle 17 penetrating the volute case part 34 protrudes into the cover part 51, and the diamond wheel 19 attached to the tip of the spindle 17 is attached to the cover part 51. Arranged inside. That is, the cover portion 51 covers the entire outer periphery of the diamond grindstone wheel 19 attached to the spindle 17.

  In order to close the gap formed between the tip of the cover 51 and the surface of the work material when the diamond wheel 19 contacts the surface of the work material, a skirt (seal) is provided at the tip of the cover 51. Member) 52 is provided.

  The skirt 52 is formed in a cylindrical shape having a smaller diameter than the cover portion 51, and is arranged in a state where the tip protrudes inside the cover portion 51. In the illustrated case, the skirt 52 is made of felt, but may be formed of other members such as a brush or a sponge.

  An annular holding piece 53 made of resin is fixed to the upper end of the skirt 52, and a spring member 54 such as a spring is disposed between the holding piece 53 and the bottom wall 37. The skirt 52 is movable in the axial direction inside the cover portion 51 together with the holding piece 53, and is urged in the axial direction toward the opening side of the cover portion 51 by the spring member 54.

  When the surface of the diamond wheel 19 is pressed against the surface of the work material during the grinding operation, the tip of the skirt 52 is brought into sliding contact with the surface of the work material. Thereby, the gap between the tip of the cover part 51 and the surface of the work material is closed by the skirt 52. Even when the dust collecting cover 31 is inclined with respect to the surface of the work material during the grinding operation, the spring member 54 is elastically deformed in accordance with this inclination, so that the skirt 52 is placed on the surface of the work material. Can follow. Thereby, it can prevent that the dust which arises by grinding operation leaks out of the cover part 51 from between the front-end | tip of the cover part 51, and the surface of a workpiece.

  When the attachment part 42 of the volute case part 34 is fixed to the boss part 16a and the dust collecting cover 31 is attached to the disc grinder 11, the entire outer periphery of the diamond grinding wheel 19 is covered with the cover part 51, and the diamond grinding wheel The back side opposite to the ground surface 19 is covered with a volute case 34. When the dust collecting cover 31 is attached to the disc grinder 11, the spindle 17 penetrating the through hole 47 of the volute case portion 34 is inserted into the attachment hole 32 c of the centrifugal fan 32, and the centrifugal fan 32 is connected to the diamond grindstone wheel 19. It is fixed to the spindle 17 between the mounting portion 42 (boss portion 16a).

  Therefore, when the electric motor 14 is operated with the dust cover 31 attached to the disc grinder 11, the centrifugal fan 32 rotates with the diamond grinding wheel 19 and generates a suction force at the suction port 48 of the volute case part 34. Due to this suction force, dust such as grinding powder generated in the cover portion 51 during the grinding operation is sucked into the volute case portion 34 from the suction port 48 and passes through the volute channel 39 via the centrifugal fan 32. It is discharged from the discharge duct 41 and collected in the dust collection bag 33.

  Next, positioning means provided on the dust collecting cover 31 will be described.

  In the dust cover 31, the centrifugal fan 32 is detachably accommodated in the volute case part 34. Therefore, when the dust cover 31 is attached to and detached from the disc grinder 11, the volute case part 34 and the centrifugal fan are arranged. 32 can be attached and detached as one unit.

  On the other hand, the volute case part 34 has a structure including a volute flow path 39 on the outer peripheral side of the fan housing chamber 38, so that the interval between the centrifugal fan 32 and the inner surface of the peripheral wall 35 is different at each position in the circumferential direction. Therefore, it is difficult to position the centrifugal fan 32 in the radial direction by the inner surface of the peripheral wall 35 so as to be coaxial with the fan housing chamber 38 inside the volute case portion 34.

  Therefore, in the present invention, the circular recess 61 is provided on the inner surface of the volute case 34 facing the axial direction, that is, the inner surface of the top wall 36, and the substrate 32 b of the centrifugal fan 32 is disposed in the circular recess 61, thereby Is removed from the disc grinder 11 (boss portion 16a), the centrifugal fan 32 is positioned in the radial direction inside the volute case portion. That is, in the dust collecting cover 31, the circular recess 61 and the substrate 32b constitute a positioning means.

  The circular recess 61 is formed in the inner surface of the top wall 36 so as to be recessed in a circular shape in the axial direction, and is disposed coaxially with the fan housing chamber 38 and the through hole 47. Further, the inner diameter dimension of the circular recess 61 is slightly larger than the outer diameter dimension of the substrate 32b of the centrifugal fan 32, and the depth dimension is also slightly larger than the thickness dimension of the substrate 32b. The centrifugal fan 32 is positioned in the radial direction within a range in which the outer peripheral portion of the substrate 32 b abuts against the inner peripheral surface of the circular recess 61 by arranging the substrate 32 b in the circular recess 61. That is, the centrifugal fan 32 is positioned at the axis of the fan housing chamber 38 that is coaxial with the spindle 17 when the volute case 34 is fixed to the boss 16a by arranging the substrate 32b in the circular recess 61. Will be.

  In a state in which the dust collection cover 31 is mounted on the disc grinder 11, the centrifugal fan 32 is arranged so that the surface of the substrate 32b on the side where the blades 32a are provided coincides with the opening end of the circular recess 61 in the axial direction. The As a result, the wind can flow smoothly from the centrifugal fan 32 to the volute channel 39.

  The dust collecting cover 31 includes an inclined surface 62 provided on the inner surface of the bottom wall 37 of the volute case portion 34 and a centrifugal fan 32 facing the inclined surface 62 in addition to the positioning means by the circular recess 61 and the substrate 32b. The positioning means is configured also by the inclined side portion 32d provided on the blade 32a.

  The inclined surface 62 is formed in an annular shape so as to be connected to the inner surface of the bottom wall 37 so as to connect the suction port 48 and the volute channel 39. In addition, the inclined surface 62 is inclined in the same direction as the inclined side portion 32d provided on the blade 32a of the centrifugal fan 32, that is, in a direction closer to the top wall 36 toward the outer side in the radial direction. And slightly curved so as to have a convex shape.

  When the centrifugal fan 32 receives a load in the radial direction and the inclined side portion 32d of each blade 32a comes into contact with the inclined surface 62, movement of the centrifugal fan 32 in the radial direction is restricted. Positioned in the radial direction inside the volute case 34. Further, when the inclined side portion 32 d of each blade 32 a comes into contact with the inclined surface 62 while receiving the weight of the centrifugal fan 32, the centrifugal fan 32 is guided along the inclined surface 62 toward the axis of the fan housing chamber 38. Then, it is positioned at the axial center of the fan housing chamber 38 inside the volute case 34.

  By providing such positioning means, in the dust collection cover 31 of the present invention, the dust collection cover 31 is removed from the disc grinder 11 in the centrifugal fan 32 that is detachably housed inside the volute case portion 34. Even in the state, it can be positioned inside the volute case portion 34 and positioned in the fan housing chamber 38. Therefore, when attaching the dust collecting cover 31 to the disc grinder 11, if the attachment part 42 of the volute case part 34 is attached to the boss part 16a, the centrifugal fan 32 can be adjusted without greatly adjusting its radial position. It can be mounted on the spindle 17. That is, the volute case part 34 and the centrifugal fan 32 can be attached to and detached from the disc grinder 11 as one unit.

  After the dust collecting cover 31 is attached to the disc grinder 11, the diamond grindstone wheel 19 is attached to the tip of the spindle 17 by the nut 22.

  On the other hand, when removing the dust collecting cover 31 from the disc grinder 11, after removing the diamond grinding wheel 19 from the spindle 17, the centrifugal fan 32 is housed inside the volute case 34 and the volute case 34 and the centrifugal fan 32. Can be removed from the disc grinder 11 together.

  As described above, according to the present invention, the centrifugal fan 32 is detachably accommodated in the volute case portion 34, and the centrifugal fan 32 is kept inside the volute case portion 34 even when the dust collecting cover 31 is removed from the disc grinder 11. Since it is positioned in the radial direction, when the dust collecting cover 31 is attached to the disc grinder 11, the volute case portion 34 is fixed to the boss portion 16a so that the centrifugal fan 32 is positioned in the radial direction. It can be mounted on the spindle 17 without adjustment. When removing the dust collecting cover 31 from the disc grinder 11, the centrifugal fan 32 can be removed from the spindle 17 together with the case portion 34 by removing the volute case portion 34 from the boss portion 16 a. Thereby, the attaching / detaching work of the dust collecting cover 31 to the disc grinder 11 can be facilitated.

  Further, in the present invention, the centrifugal fan 32 is attached to the volute case portion 34 by the structure in which the disc-shaped substrate 32 b provided on the centrifugal fan 32 is disposed in the circular recess 61 provided on the inner surface facing the axial direction of the volute case portion 34. Since the radial fan is positioned inside in the radial direction, the centrifugal fan 32 can be positioned in the radial direction inside the volute case with a simple configuration, and the load applied from the centrifugal fan 32 of the volute case is also shown in FIG. It is possible to increase the volume of the portion that supports and increase the strength and durability.

  Further, in the present invention, in addition to the structure in which the substrate 32 b of the centrifugal fan 32 is disposed in the circular recess 61 provided in the volute case portion 34, the centrifugal fan 32 is provided on the inclined surface 62 provided on the bottom wall 37 of the volute case portion 34. Since the centrifugal fan 32 is positioned in the radial direction inside the volute case portion 34 even by the structure in which the inclined side portions 32d face each other, the centrifugal fan 32 is reliably positioned in the radial direction inside the volute case portion 34. can do. Further, since the blades 32a of the centrifugal fan 32 can be provided with positioning means with a simple configuration using the inclined side portions 32d provided to make the passage cross-sectional area constant, the dust collecting cover 31 can be configured. The cost can be reduced.

  FIG. 5 is a sectional view showing a modification of the dust collecting cover shown in FIG. 2 and showing a structure in which a cylindrical convex portion provided in the centrifugal fan is arranged in an annular concave portion provided in the inner surface of the volute case portion.

  In the case shown in FIG. 2, the positioning means is configured by arranging the substrate 32 b of the centrifugal fan 32 in a circular recess 61 provided in the volute case portion 34. On the other hand, in the modification shown in FIG. 5, an annular recess 63 is provided on the inner surface of the top wall 36 that is the inner surface facing the axial direction of the volute case portion 34, and the annular recess 63 is provided on the substrate 32 b of the centrifugal fan 32. The cylindrical convex portion 64 is arranged. That is, in this case, the positioning means is configured by the annular concave portion 63 provided in the volute case portion 34 and the cylindrical convex portion 64 provided in the centrifugal fan 32.

  The annular recess 63 is formed as an annular groove having a rectangular cross section, and is arranged coaxially with the fan housing chamber 38. On the other hand, the cylindrical convex portion 64 is formed in a cylindrical shape protruding in the axial direction from the back surface facing the top wall 36 of the substrate 32b, and is disposed coaxially with the substrate 32b of the centrifugal fan 32. The groove width of the annular recess 63 is formed to be slightly larger than the thickness of the cylindrical convex portion 64, and the centrifugal fan 32 is arranged so that the cylindrical convex portion 64 is disposed in the annular concave portion 63. The side portion of the portion 64 is positioned in the radial direction within a range where the side portion contacts the side wall of the annular recess 63.

  In this modification, the annular recess 63 and the cylindrical protrusion 64 are disposed on one side in the axial direction with respect to the centrifugal fan 32, and therefore no positioning means is disposed between the volute channel 39 of the centrifugal fan 32. It is a configuration. Therefore, the cross-sectional area of the volute channel 39 provided on the radially outer side of the centrifugal fan 32 can be increased.

  As described above, in the modification shown in FIG. 5, the cylindrical convex portion 64 provided on the substrate 32 b of the centrifugal fan 32 is arranged in the annular concave portion 63 provided on the inner surface of the top wall 36 of the volute case portion 34, thereby 32 is positioned in the radial direction inside the volute case portion 34, so that the positioning means is disposed on the axial direction side with respect to the centrifugal fan 32, and the volute flow path formed on the radially outer side of the centrifugal fan 32. The cross-sectional area of 39 can be increased.

  In FIG. 5, members corresponding to those described above are denoted by the same reference numerals.

  It goes without saying that 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, in the above-described embodiment, the disk grinder 11 of the present invention is exemplified by using an electric motor as a drive source. However, the present invention is not limited to this, and for example, a disk grinder provided with another drive source such as an air motor. You may make it apply this invention to.

  In the embodiment, in addition to the positioning means having the structure in which the dust collecting cover 31 and the substrate 32b of the centrifugal fan 32 are arranged in the circular recess 61 provided in the top wall 36 of the volute case part 34, the volute case part However, the present invention is not limited to this, and only one of the positioning means is provided. You may do it.

  Further, in the above-described embodiment, as a positioning means, a structure in which the substrate 32b of the centrifugal fan 32 is disposed in the circular recess 61 provided in the top wall 36 of the volute case part 34, and the top wall 36 of the volute case part 34 are provided. A structure in which the cylindrical convex portion 64 provided on the substrate 32b of the centrifugal fan 32 is disposed in the annular concave portion 63, and the inclined side portion 32d of the centrifugal fan 32 is engaged with the inclined surface 62 provided on the bottom wall 37 of the volute case portion 34. However, the present invention is not limited to these, and the concave portion provided in one of the volute case portion 34 and the centrifugal fan 32 is provided in the concave portion provided in one of the volute case portion 34 and the centrifugal fan 32. If the configuration is such that the centrifugal fan 32 is positioned radially inside the volute case 34 by arranging the portions, the concave or convex May be used positioning means having a different shape as a.

  Further, in the above embodiment, the annular recess 63 is provided in the top wall 36 of the volute case 34 and the cylindrical protrusion 64 is provided in the substrate 32b of the centrifugal fan 32. However, the ceiling of the volute case 34 is provided. A cylindrical convex portion 64 may be provided on the wall 36, and an annular concave portion 63 may be provided on the substrate 32 b of the centrifugal fan 32.

DESCRIPTION OF SYMBOLS 11 Disc grinder 13 Main body case 14 Electric motor 15 Power cord 16 Gear case 16a Boss part 17 Spindle 18a, 18b Bevel gear 19 Diamond grindstone wheel 19a Substrate 19b Diamond grindstone 21 Washer 22 Nut 31 Dust collection cover 32 Centrifugal fan 32a Blade 32b Substrate 32c Mounting hole 32d Inclined side portion 33 Dust collection back 34 Volute case portion 34a First case half 34b Second case half 35 Peripheral wall 36 Top wall 37 Bottom wall 38 Fan housing chamber 39 Volute flow path 41 Discharge duct (discharge port)
42 Attachment part 42a 1st adapter 42b 2nd adapter 43a Bolt (connection member)
43b Nut (connecting member)
44a Bolt 44b Nut 45 Cam mechanism (fixing means)
45a cam 46 lock arm 46a locking portion 47 through hole 48 suction port 51 cover portion 52 skirt 53 holding piece 54 spring member 61 circular recess 62 inclined surface 63 annular recess 64 cylindrical projection

Claims (6)

A dust collecting cover attached to a portable disc grinder capable of attaching a tip tool to a spindle,
A mounting portion attachable to the disc grinder;
A cylindrical cover portion provided on an axial end surface facing away from the mounting portion, and covering an outer periphery of the tip tool;
A volute case part that includes a volute channel that is continuous with the discharge port, and that is fixed to the disc grinder with the suction port facing the tip tool;
A centrifugal fan housed in the volute case part and attached to the spindle between the tip tool and the attachment part;
First positioning means for positioning the centrifugal fan in a radial direction inside the volute case when the volute case is removed from the disc grinder;
The first positioning means includes a circular recess provided in an inner surface of the volute channel and facing the axial direction of the volute case, and a circle provided in the centrifugal fan and disposed in the circular recess. A plate-shaped substrate,
The dust collecting cover, wherein the volute case part can be attached to and detached from the disc grinder while the centrifugal fan is accommodated. A second positioning means for positioning the centrifugal fan in the radial direction inside the volute case when the volute case is removed from the disc grinder;
The second positioning means is provided on an annular inclined surface provided on the inner surface facing the axial direction of the volute case portion so as to be inclined with respect to the axial direction, and on an end surface facing the inclined surface of the centrifugal fan. dust collection cover according to claim 1, characterized in that it is made Ri構 by the the inclined side portion inclined to the inclined face in the same direction Te. The dust collecting cover according to claim 2, wherein the first positioning means and the second positioning means are provided on both sides in the axial direction of the centrifugal fan, respectively. The mounting portion, the includes a fixing means for enabling attachment to a disk grinder, the fixing means dust collecting according to any one of claims 1 to 3, wherein the manually externally operable cover. The mounting portion, the volute provided in the case portion, and the first adapter semi-cylindrical for engaging the outer peripheral surface of the ball scan section, and the first adapter is formed in a semicylindrical separate, the boss A second adapter combined with the first adapter across a portion, a connecting member connecting the first adapter and one end of the second adapter, and connecting the other end of the first adapter and the second adapter And a cam mechanism that can be driven in a direction that narrows the distance between each other, and a lock arm that operates the cam mechanism, and the first adapter and the second adapter are in a fixed state to sandwich the boss portion. 5. The dust collecting cover according to claim 4 , wherein the lock arm is disposed along the outer surface of the volute case part in the entire longitudinal direction. A housing that houses an electric motor;
A spindle extending from the housing and fitted with a tip tool;
A mounted portion arranged around the spindle;
Disc grinder being characterized in that and a dust collection cover according to any one of claims 1 to 5, wherein attached to the attached portion covering the tip tool.

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