JP7633408B2 - Rotary tools - Google Patents

Description

The present invention relates to a rotary tool that is attached to a rotating shaft and is used to grind surfaces such as concrete and stone.

In grinding operations using power tools such as disc grinders and sanders, air tools, and engine tools to grind the surfaces of materials to be ground such as concrete, stone, and metal, a grinding wheel, i.e., a rotating tool, is used as the tip tool. The rotating tool has a cup-type base plate with a cup-shaped central portion and an outer periphery extending radially, and is disc-shaped, i.e., wheel-shaped, with multiple grinding tips, i.e., abrasive grain layers, fixed to the outer surface of the base plate. The rotating tool is attached to the output shaft, i.e., spindle, of the power tool at the center of the base plate before use.

In grinding work using such power tools, the grinding tip is pressed against the material to be ground, so the vibrations caused by the impact during grinding are transmitted directly to the worker, making it difficult to work continuously for long periods of time. For this reason, as described in Patent Document 1, a rotary tool has been proposed that is equipped with a vibration reduction mechanism between the mounting part of the power tool and the rotary tool, reducing the vibration to the worker during grinding work.

JP 2013-226650 A

However, the rotary tool described in Patent Document 1 has a configuration in which a ring-shaped elastic body is brought into contact with a metal substrate and sandwiched between a washer and the rotary tool, and there is a problem that the weight of the rotary tool as a whole increases due to the increased number of parts. Also, if the substrate is made of a material other than metal that has a vibration reducing effect, there is a problem that deformation of the substrate itself puts a strain on the abrasive layer, i.e., the joint of the polishing tip, and the product life is shortened.

The present invention has been made in consideration of the above problems, and its purpose is to provide a rotating tool that reduces vibrations transmitted to the operator while minimizing an increase in weight and suppresses a decrease in product life.

The present invention is a rotary tool that is attached to the output shaft of a power tool, and includes a resin substrate formed into a disk shape from a resin material, and a plurality of grinding chips arranged circumferentially on the outer periphery of the resin substrate, the grinding chips including a holding plate and an abrasive grain layer held by the holding plate, and each of the grinding chips is independently fixed integrally to the resin substrate.

Multiple grinding chips with an abrasive layer and a holding plate are placed on a resin substrate, preventing the weight of the rotary tool from increasing. The abrasive layers are separated from each other and fixed to the resin substrate, so that the vibrations applied to the abrasive layer during grinding are absorbed by the resin substrate, reducing the vibrations transmitted to the operator. The abrasive layer is bonded to the holding plate, preventing damage to the abrasive layer and reducing the product lifespan.

1 is a side view showing a power tool to which a rotary tool according to an embodiment is attached; FIG. 2 is an enlarged cross-sectional view of the rotary tool shown in FIG. 1 . FIG. FIG. 2 is an enlarged front view showing one grinding tip attached to a resin substrate. FIG. 3 is an enlarged cross-sectional view of part A in FIG. 2 . 5 is a cross-sectional view taken along line BB in FIG. 4. 1A and 1B are cross-sectional views showing the state in which the surface of a workpiece is being ground using a rotating tool attached to a power tool, in which (A) shows the state in which all of the abrasive grain layers are pressed against the surface of the workpiece, and (B) shows the state in which only a portion of all of the abrasive grain layers are pressed against the surface of the workpiece. 1 is a cross-sectional view showing a state in which a grinding tip attached to a flexible resin substrate follows and grinds the undulations and undulations of a surface to be ground. FIG. 11 is a front view showing one grinding tip in a rotary tool according to another embodiment. 10 is an enlarged cross-sectional view of line CC in FIG. 9. FIG. 11 is a cross-sectional view showing a grinding tip in a rotary tool according to another embodiment. FIG. 11 is a cross-sectional view showing a grinding tip in a rotary tool according to another embodiment. FIG. 11 is a cross-sectional view showing a grinding tip in a rotary tool according to another embodiment.

Below, the embodiment of the present invention is described in detail based on the drawings.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In each drawing, the same reference numerals are used to designate common components.

Figure 1 shows a power tool 1 used to grind the surface of a workpiece such as stone or metal. This power tool 1 is an electric tool in which an output shaft 3 extending perpendicularly to the case body 2 is provided at the tip of the case body 2 in which an electric motor (not shown) is built, and the output shaft 3 is rotated by the electric motor. A grinding wheel as the tip tool, that is, a rotating tool 10, is attached to the output shaft 3 by a mounting bracket 4 on the rear side and a mounting bracket 5 on the front side. The mounting bracket 5 is a nut that is screwed into a male thread (not shown) provided at the tip of the output shaft 3.

As shown in FIG. 2, the rotary tool 10 has a resin substrate 11 formed into a disk shape from a resin material. The resin substrate 11 has a mounting portion 12 that is mounted on the output shaft 3 by mounting brackets 4 and 5, and a mounting portion 13 that is offset forward of the output shaft 3 relative to the mounting portion 12, and an inclined wall portion 14 is provided between the mounting portion 12 and the mounting portion 13. The inclined wall portion 14 has an overall truncated cone shape, and the resin substrate 11 is a cup type in which the central portion is formed into a cup shape by the mounting portion 12 and the inclined wall portion 14, and the mounting portion 13, which is the outer periphery, extends in the radial direction. When the resin substrate 11 is mounted on the output shaft 3, the surface facing the workpiece to be ground is the front or front surface, and the opposite surface is the back or back surface.

Fiber-reinforced plastic (FRP) containing fiber and resin is used as the resin material of the resin substrate 11. As the fiber-reinforced plastic, GFRP is used, which uses epoxy resin as the base material and glass fiber as the reinforcing material. However, the base material, i.e., the matrix, may be other thermosetting resins such as unsaturated polyester and phenolic resin, or may be GFRTP using thermoplastic resins such as polyamide resin, polycarbonate resin, and polyphenylene sulfide resin, and further, CFRP or CFRTP using carbon fiber as the reinforcing material may be used as the resin material. In this way, the resin substrate 11 made of a resin material such as fiber-reinforced plastic is elastically deformable and flexible compared to substrates made of metal or hard resin.

A collar 15 made of a metal material is fixed to the center of the mounting portion 12, and the collar 15 has a hollow shaft portion 16 through which the output shaft 3 passes, and a flat portion 17 that is disposed on the surface side of the mounting portion 12. The resin board 11 is attached to the output shaft 3 by abutting the mounting bracket 4 against the back surface of the mounting portion 12 and fastening the mounting bracket 5 to the surface of the flat portion 17.

3, a plurality of grinding chips 18 are arranged in the circumferential direction on the outer periphery of the resin substrate 11, i.e., on the surface of the outer periphery of the mounting portion 13. In this rotary tool 10, a total of ten grinding chips 18 are arranged separately and independently on the outer periphery of the resin substrate 11 at regular intervals in the circumferential direction, and each grinding chip 18 is fixed to the resin substrate 11 and integrated therewith.

Each grinding chip 18 includes a metal holding plate 21 fixed to the surface of the resin substrate 11 and an abrasive layer 22 held by the holding plate 21. The holding plate 21 is attached to a range spanning the radial center of the mounting part 13 offset forward of the output shaft 3 relative to the mounting part 12, and the abrasive layer 22 is attached to the radial outer periphery of the holding plate 21. The abrasive layer 22 is a hard sintered body formed by heating and sintering a mixed powder of abrasive grains made of granular synthetic diamond and a bond (metal bond) in a heating furnace, and is also called a segment, sintered chip, or simply a chip. As the abrasive grains, abrasive grains such as CBN (cubic boron nitride) and GC (green silicon carbide) can be used instead of synthetic diamond. In addition, as the metal used for the metal bond, cobalt, nickel, iron, tungsten carbide, tungsten, bronze, etc., or known materials mixed with them can be used. Moreover, instead of a metal bond, any bond such as a resinoid bond, a vitrified bond, etc. may be used. The abrasive layer 22 may be a so-called sintered diamond (PCD) having a low ratio of a bond.

Figure 4 is an enlarged front view showing one grinding tip 18 attached to the resin substrate 11. Figure 5 is an enlarged cross-sectional view of part A in Figure 2, and Figure 6 is a cross-sectional view of line B-B in Figure 4.

4 and 5, the holding plate 21 has an arc-shaped outer peripheral surface 23 and an inner peripheral surface 24 that each extend in the circumferential direction of the resin substrate 11, and the outer peripheral surface 23 and the inner peripheral surface 24 have the same center of curvature O, which is the central axis of rotation of the circular resin substrate 11. Both end faces 25 in the circumferential direction of the holding plate 21 are curved surfaces that are convex toward the outside of the end faces 25. The material of the holding plate may be a hard resin, etc.

3, if the distance between the outer peripheral surfaces 23 of the two grinding chips 18 facing each other via the central axis of rotation O, i.e., the diameter of the rotary tool 10, is D1, and the distance between the inner peripheral surfaces 24 of the two grinding chips 18 facing each other is D2, the diameter D1 is 100 mm and the diameter D2 is 84 mm. The chip angle α in the circumferential direction of each grinding chip 18 is 24 degrees, and the gap angle β in the circumferential direction between two adjacent grinding chips 18 in the circumferential direction is 11 degrees.

The abrasive layer 22 fixed to the holding plate 21 has an outer peripheral surface 26 and an inner peripheral surface 27. The outer peripheral surface 26 is an arcuate surface with a radius of curvature R1 and a center of curvature O, similar to the outer peripheral surface 23 of the holding plate 21, and is continuous and flush with the outer peripheral surface 23. In contrast, the inner peripheral surface 27 is an arcuate surface with a radius of curvature R3 and a center of curvature P located at a position shifted radially outward from the center of curvature O of the outer peripheral surface 26.

In FIG. 4, the imaginary line M is an arc surface with a curvature radius R2, with the center of curvature O of the outer peripheral surface 26 as the center of curvature. If the inner peripheral surface 27 is an arc surface indicated by the imaginary line M, and the centers of curvature of the outer peripheral surface 26 and the inner peripheral surface 27 are the same point O, the radial thickness dimension of the abrasive layer 22 will be approximately the same along the circumferential direction. In contrast, as shown in FIG. 4, if the center of curvature O of the inner peripheral surface 27 is shifted radially outward relative to the center of curvature O of the outer peripheral surface 26, the thickness W2 of both ends of the circumferential direction of the abrasive layer 22 will be thicker than the thickness W1 of the central portion in the circumferential direction. In other words, the abrasive layer 22 has a portion with a larger radial thickness on the circumferential end side than the central portion in the circumferential direction. This allows the rotational impact applied to both ends of the abrasive layer 22 during grinding to be appropriately distributed, and it is possible to suppress damage caused by localized force application. The thickness W1 is 5 mm, while the thickness W2 is 8 mm.

As shown in FIG. 5, the thickness of the resin substrate 11 is t1, and the thickness of the holding plate 21 is t2. The thickness t1 is 1.4 mm, and the thickness t2 is 1 mm. The thickness t2 is preferably thin and lightweight while ensuring the strength required for fixing to the resin substrate 11, and is formed to be the same as or thinner than the thickness t1. Preferably, the thickness t2 is in the range of 0.1 to 0.8 times the thickness t1, and more preferably, in the range of 0.5 to 0.75 times the thickness t1. Furthermore, the height of the abrasive layer 22, that is, the dimension in the direction along the central axis of rotation, is h, and the height h is 4 mm. The front surface of the abrasive layer 22 is the grinding surface 29 that is pressed against the surface of the workpiece to be ground.

Both circumferential end faces of the abrasive layer 22 are inclined surfaces 28 inclined with respect to a radial line. The inclined surfaces 28 have an outward inclined surface 28a radially outward from the radial center of the abrasive layer 22, and an inward inclined surface 28b radially inward from the center. The outward inclined surface 28a faces the radially outward side of the rotating tool 10, centered on a radial line that contacts the protruding end of the convex curved surface of the inclined surface 28. In contrast, the inward inclined surface 28b faces the radially inward side of the rotating tool 10.

The grinding chip 18 has a holding plate 21 and an abrasive layer 22 bonded thereto, and is fixed to the outer periphery of the surface of the resin substrate 11, and the multiple grinding chips 18 are separated from each other. Since the abrasive layer 22 is bonded to the metal or hard resin holding plate 21, it does not tilt or displace relative to the holding plate 21 during grinding. In contrast, as shown in FIG. 3, the region 30 of the resin substrate 11 between the grinding chips 18 adjacent in the circumferential direction is a flexible region that can elastically deform in response to the displacement of the grinding chip 18 during grinding. As a result, the grinding chip 18 can be displaced relative to the resin substrate while maintaining its overall shape without being deformed during grinding. A rotary tool 10 equipped with 10 grinding chips 18 has 10 flexible regions 30.

5, the holding plate 21 has a joining hole 31 penetrating the holding plate 21, and the abrasive layer 22 has a convex portion 32 that enters the joining hole 31. As shown in FIG. 6, three joining holes 31 are formed at intervals in the circumferential direction of the resin substrate 11, and the convex portion 32 of the abrasive layer 22 enters each joining hole 31. Therefore, the abrasive layer 22 is joined to the surface of the holding plate 21 and the convex portion 32 is joined to the inner peripheral surface of the joining hole 31, so that the holding plate 21 and the abrasive layer 22 are joined in a stepped or zigzag shape in the circumferential direction of the resin substrate 11, as shown in FIG. 6. This makes it possible to prevent the abrasive layer 22 from peeling off the holding plate 21, and to prevent a decrease in product life.

To manufacture the abrasive tip 18, the holding plate 21 with holes machined as joining holes 31 is placed in a sintering die, and with the holding plate 21 in place, a mixture of abrasive grains and bond is filled into the sintering die and heated. As a result, the abrasive grain layer 22 to which the holding plate 21 is joined is insert molded in the sintering die. As described above, the holding plate 21 and the abrasive grain layer 22 are joined in a stepped shape, which increases the joining strength.

The abrasive layer 22 is inserted into the joining hole 31 formed through the holding plate 21, but it is also possible to form a groove with a bottom in the holding plate 21 and insert the abrasive layer 22 into the groove, thereby joining the holding plate 21 and the abrasive layer 22 at a stepped joining surface.

Each of the holding plates 21 is fixed to the resin substrate 11 by two rivets 33. As shown in FIG. 5, the resin substrate 11 has a mounting hole 34 as a grinding chip fixing portion, and each holding plate 21 has two tapered rivet holes 35. The rivet 33 is a protrusion that protrudes from the holding plate 21 toward the resin substrate 11, and the rivet 33 as a protrusion is inserted into the mounting hole 34 as a grinding chip fixing portion to fix the holding plate 21 to the resin substrate 11. When the holding plate 21 and the resin substrate 11 are fixed by the rivet 33, the holding plate 21 can be formed of a metal plate thinner than the resin substrate 11, and imbalance in rotational balance due to variations in the weight of the grinding chip 18 can be suppressed.

To fix the holding plate 21 to the resin substrate 11 with the rivet 33, which is separate from the resin substrate 11 and the holding plate 21, the rivet 33 is attached in advance to the mounting hole 34 of the resin substrate 11, the rivet 33 protruding from the mounting hole 34 of the resin substrate 11 is inserted into the crimping hole 35 of the holding plate 21, and the tip of the rivet 33 is plastically deformed from the side opposite the insertion side of the crimping hole 35. Alternatively, the rivet 33 as the protruding part may be fixed to the holding plate 21 by welding, and the rivet 33 may be inserted into the mounting hole 34 to plastically deform the head of the rivet 33.

As shown in Fig. 4, the radial position of each rivet 33 relative to the holding plate 21 overlaps radially within the groove 36 formed by the inner circumferential surface 27 of the abrasive layer 22. In this way, by utilizing the groove 36 formed by the inner circumferential surface 27 and arranging the rivet 33 in the space, the fixing strength between the holding plate 21 and the resin substrate 11 can be increased without increasing the size of the holding plate 21. Furthermore, the abrasive layer 22 is set to have a smaller thickness at the circumferential center than at the circumferential end sides, and the rivet 33 is arranged on the circumferential center side, so that the thickness of both ends in the circumferential direction can be increased, and the contact area between the grinding surface 29 of the abrasive layer 22 and the grinding material can be increased, and the increase in surface pressure can be suppressed.

7 is a cross-sectional view showing the state in which the surface S of the workpiece V is ground by the rotary tool 10 attached to the power tool. Fig. 7(A) shows the state in which the grinding surfaces 29 of all the abrasive grain layers 22 are pressed against the workpiece S of the workpiece, and even if the grinding surfaces 29 of all the abrasive grain layers 22 are tilted within the range of angle a around the rotation axis O, the pressed state of the grinding surfaces 29 of all the abrasive grain layers 22 is maintained. On the other hand, Fig. 7(B) shows the state in which some of the grinding surfaces 29 of all the abrasive grain layers 22 are in contact with the grinding surface S of the workpiece V, and by tilting the rotation axis O at angle b, the grinding surfaces 29 of some of the abrasive grain layers 22 are pressed against the grinding surface S, and the other abrasive grain layers 22 are separated from the grinding surface S.

When the abrasive layer 22 is pressed against the grinding surface S of the grinding member V, the resin substrate 11 has flexibility, so the inclined wall portion 14 elastically deforms so that the inner diameter on the surface side becomes larger, and the grinding surface 29 of each abrasive layer 22 is pressed against the grinding surface in its entirety, and grinding is performed. In this state, the edge of the abrasive layer 22 is less likely to bite into the grinding surface S, and the weight of the grinding tip 18 is also suppressed, so that the grinding surface S is prevented from being excessively ground. In other words, the pressing force for performing the grinding work appropriately can be made to have a range, so the amount of grinding can be easily controlled. This allows the grinding surface S to be ground with high precision. Moreover, the vibration applied to the abrasive layer 22 is absorbed by the flexible resin substrate 11, so the vibration transmitted to the operator is reduced. Since the abrasive layer 22 is bonded to the holding plate 21, no external force that would deform the abrasive layer 22 is applied, and the product life of the abrasive layer 22 can be prevented from being shortened.

As shown by the symbol F in FIG. 7A, when the grinding surface 29 of the abrasive layer 22 is pressed against the grinding surface S while grinding the grinding surface S, if there is a protrusion (also called a wavy or undulating surface) on the surface of the grinding surface S, the protrusion will abut against the end face of the abrasive layer 22. At this time, as shown in FIG. 8, the chip-to-chip region 30 between two adjacent grinding chips 18 in the resin substrate 11 can be elastically deformed, so that one end face of each grinding chip 18 displaces in a direction away from the grinding surface S, riding on the protrusion and grinding the protrusion. In other words, the grinding chip 18 displaces in accordance with the surface of the grinding surface S, enabling a uniform grinding operation with little unevenness in the amount of grinding. Even in such an operation, excessive grinding caused by the edge of the abrasive layer 22 biting into the grinding surface S is suppressed. Furthermore, since the resin substrate 11 does not contain metal materials, even if it is repeatedly elastically deformed due to the displacement of the grinding chip 18, metal fatigue does not occur, and damage to the resin substrate 11 can be suppressed, thereby suppressing a decrease in the product life.

The end face of the abrasive layer 22 is an inclined surface 28 inclined relative to a radial line, so that even if a protrusion of the workpiece to be ground hits the end face, the abrasive layer 22 is prevented from being damaged, and the corners formed by the inclined surface 28 are prevented from impeding the deformation of the resin substrate 11. If the inclined surface 28 is formed by an outward inclined surface 28a and an inward inclined surface 28b, the inclined surface 28 can be formed on the end face without increasing the circumferential length of the abrasive layer 22.

The circumferential tip angle α of the grinding chip 18 is set to 24 degrees, and the gap angle β is set to 11 degrees, but the angles at which the region 30 in the resin substrate 11 between two adjacent grinding chips 18 can exhibit flexibility are not limited to these angles. Experiments have shown that the tip angle α can be between 10 degrees and 30 degrees, and the gap angle β can be between 7 degrees and 20 degrees. Furthermore, the thickness t1 of the resin substrate 11, the thickness t2 of the holding plate 21, and the height h of the abrasive layer 22 are not limited to the above-mentioned values.

The retaining plate 21 is attached in an area spanning the radial center of the mounting portion 13, which is offset relative to the attachment portion 12. As a result, as shown by the imaginary line T in Figure 2, even if the abrasive layer 22 wears, the connection portion 19 between the inclined wall portion 14 and the mounting portion 13 can be protected.

Figure 9 is a front view showing one grinding tip 18 in a rotary tool of another embodiment, and Figure 10 is an enlarged cross-sectional view of line CC in Figure 9.

In this abrasive chip 18, a joining groove 41 is formed on the outer peripheral surface 23 and end surface 25 of the holding plate 21, and a protrusion 42 that fits into each joining groove 41 is provided in the abrasive layer 22. In this way, the joining portion of the abrasive layer 22 with the holding plate 21 has the joining groove 41 and the protrusion 42, and the holding plate 21 and the abrasive layer 22 are joined in a stepped or zigzag shape in the circumferential direction of the resin substrate 11, increasing the joining strength.

Figures 11 and 12 are cross-sectional views showing other embodiments of the grinding tip 18.

In the grinding chip 18 shown in Figure 11, a joining groove 43 is formed on the back surface of the abrasive grain layer 22, and a protrusion 44 that fits into the joining groove 43 and joins is provided protruding forward on the surface of the holding plate 21. The joining groove 43 and the protrusion 44 are provided in multiple pieces, for example, three pieces each, along the circumferential direction, similar to the joining holes 31 and protrusions 32 shown in Figures 4 and 5.

In the grinding chip 18 shown in Figure 12, a joining groove 45 is formed on the surface of the holding plate 21, and a protrusion 46 that is joined to the joining groove 45 is provided in the abrasive layer 22. The joining grooves 45 and protrusions 46 are provided in pairs in the radial direction, and further provided in multiple pairs, for example three pairs, in the circumferential direction. In this form of grinding chip 18, the holding plate 21 and the abrasive layer 22 are joined in a stepped shape in the circumferential direction, and are also joined in a stepped shape in the radial direction.

As shown in Figures 9 to 12, by joining the holding plate 21 and the abrasive layer 22 in a stepped manner, the joining strength can be increased, and even if vibrations are applied to the abrasive layer 22 during grinding, the abrasive layer 22 and the holding plate 21 are prevented from separating or being damaged, thereby suppressing a decrease in product life.

Figure 13 is a cross-sectional view showing an abrasive tip 18 according to another embodiment, in which a coaxial joining hole 47 is formed in the holding plate 21 and the rivet 33, and a protrusion 48 that is joined to this joining hole 47 is provided in the abrasive layer 22. In this way, by joining the protrusion 48 to the holding plate 21 and also to the rivet 33, the joining strength between the abrasive layer 22, the holding plate 21 and the rivet 33 can be increased. In this embodiment, the holding plate 21 and the rivet 33 are molded integrally when the abrasive layer 22 is sintered.

The present invention is not limited to the above embodiment, and various modifications are possible without departing from the gist of the present invention. For example, the number of grinding chips 18 attached to the resin substrate 11 is not limited to 10 as in the illustrated embodiment, and various numbers of rotary tools can be used. Similarly, the outer diameter of the rotary tool 10 can be various diameters depending on the material to be ground. The abrasive layer 22 is fixed to the holding plate 21 by incorporating the holding plate 21 into a mold and heat treating it in a sintering furnace when the abrasive layer 22 is molded by sintering, so that the abrasive layer is joined to the holding plate 21 during sintering. However, after the abrasive layer is molded, the abrasive layer may be fixed to the holding plate by electroplating or by welding using a brazing material.

The rotary tool of the present invention is applied to grinding surfaces to be inspected, such as concrete and stone.

Claims (15)

A rotary tool attached to an output shaft of a power tool,
a resin substrate formed into a disk shape from a resin material;
A plurality of grindstone chips are arranged along a circumferential direction on an outer periphery of the resin substrate,
Each of the plurality of abrasive chips includes a holding plate and an abrasive grain layer held on a surface of the holding plate;
Each of the plurality of grinding chips is independently and integrally fixed to the resin substrate by fixing the holding plate to which the abrasive grain layer is bonded to the resin substrate ,
the resin substrate includes a mounting portion that is mounted on an output shaft, a mounting portion that is offset forward from the mounting portion and to which the grinding tip is fixed, and an inclined wall portion that is provided between the mounting portion and the mounting portion;
a height from a surface of the mounting portion to a surface of the attachment portion is greater than a height from the surface of the attachment portion to a surface of the abrasive layer, and a height from the surface of the attachment portion to a surface of the holding plate is smaller than a height from the surface of the holding plate to a surface of the abrasive layer,
A rotating tool , wherein a region between adjacent grinding tips in the circumferential direction of the resin substrate and a region between the grinding tips from the inclined wall portion in the radial direction have flexibility that allows elastic deformation during grinding . The rotary tool according to claim 1 , wherein the resin substrate is made of a fiber-reinforced plastic containing fibers and a resin. The rotary tool according to claim 1 , wherein the abrasive layer has an inclined surface on an end surface in a circumferential direction that is inclined with respect to a radial line. A rotary tool attached to an output shaft of a power tool,
a resin substrate formed into a disk shape from a resin material;
A plurality of grindstone chips are arranged along a circumferential direction on an outer periphery of the resin substrate,
Each of the plurality of grindstone chips includes a holding plate and an abrasive grain layer held by the holding plate, and each of the plurality of grindstone chips is independently fixed integrally to the resin substrate;
the abrasive layer has an inclined surface on an end surface in a circumferential direction, the inclined surface being inclined with respect to a radial line;
The inclined surface has an outwardly inclined surface in which an end surface radially outer than a radial center portion is inclined outward, and an inwardly inclined surface in which an end surface radially inner than the radial center portion is inward ,
The outwardly inclined surface faces a radially outward direction of the rotary tool, and the inwardly inclined surface faces a radially inward direction of the rotary tool . A rotary tool attached to an output shaft of a power tool,
a resin substrate formed into a disk shape from a resin material;
A plurality of grindstone chips are arranged along a circumferential direction on an outer periphery of the resin substrate,
Each of the plurality of grindstone chips includes a holding plate and an abrasive grain layer held by the holding plate, and each of the plurality of grindstone chips is independently fixed integrally to the resin substrate;
The abrasive layer has an arc-shaped outer peripheral surface and an arc-shaped inner peripheral surface whose center of curvature is radially outward from the center of curvature of the outer peripheral surface, and the abrasive layer has a portion whose radial thickness is greater on the circumferential end side than on the circumferential center side. The rotary tool according to claim 1 , wherein the holding plate is attached to a range spanning a radial center portion of the attachment portion. The rotary tool described in claim 1, wherein the abrasive layer is arranged so that a portion of the abrasive layer overlaps with the holding plate in the thickness direction of the resin substrate and another portion of the abrasive layer overlaps with the holding plate in the circumferential direction of the resin substrate, thereby being joined to the holding plate in a stepped manner in the circumferential direction of the resin substrate. The rotary tool according to claim 7, wherein the abrasive layer is formed by sintering a mixed powder of abrasive grains and bond and fixed to the holding plate, and is joined to the holding plate in a stepped manner by entering a groove or hole formed in the holding plate . The resin substrate has a grindstone chip fixing portion formed of a groove or a hole,
a protrusion protruding toward the resin substrate is provided on the holding plate;
The rotary tool according to claim 1 , wherein the holding plate and the resin substrate are fixed together by inserting the protruding portion into the grindstone tip fixing portion. A rotary tool attached to an output shaft of a power tool,
a resin substrate formed into a disk shape from a resin material;
A plurality of grindstone chips are arranged along a circumferential direction on an outer periphery of the resin substrate,
Each of the plurality of grindstone chips includes a holding plate and an abrasive grain layer held by the holding plate, and each of the plurality of grindstone chips is independently fixed integrally to the resin substrate;
The resin substrate has a grindstone chip fixing portion formed of a groove or a hole,
a protrusion protruding toward the resin substrate is provided on the holding plate;
The protruding portion is inserted into the grindstone chip fixing portion, thereby fixing the holding plate and the resin substrate,
A rotary tool, wherein a radial position of the protrusion relative to the holding plate overlaps a groove formed by an arcuate inner circumferential surface of the abrasive layer. The rotary tool according to claim 1 or 2, wherein the circumferential tip angle of each of the grinding tips is in the range of 10 degrees to 30 degrees. The rotary tool according to claim 1 or 2, wherein the circumferential gap angle between adjacent grinding chips in the circumferential direction is in the range of 7 degrees to 20 degrees. A rotary tool attached to an output shaft of a power tool,
a resin substrate formed into a disk shape from a resin material;
A plurality of grindstone chips are arranged along a circumferential direction on an outer periphery of the resin substrate,
The abrasive tip includes a holding plate and an abrasive grain layer held by the holding plate,
a protruding portion extending in a direction of a central axis of rotation of the resin substrate is provided on one of the holding plate and the abrasive layer, and a joint portion into which the protruding portion fits is provided on the other of the holding plate and the abrasive layer;
the holding plate and the abrasive layer are joined to each other in a stepped manner in a circumferential direction of the resin substrate by the protrusions entering the joint portion, the rotating tool. The rotary tool according to claim 13, wherein the abrasive layer is formed by sintering a mixed powder of abrasive grains and a bond and fixed to the holding plate, and is joined to the holding plate in a stepped manner by entering a groove or hole formed in the holding plate. The rotary tool according to claim 1 , wherein the thickness of the holding plate is in the range of 0.1 to 0.8 times the thickness of the resin substrate.

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