Rotary grindstone and rotary grindstone tool

Abstract

To provide a rotary grindstone which maintains grinding performance of a cutting part, and to provide a rotary grindstone tool.SOLUTION: A rotary grindstone 100 includes: a cup shaped base 10 having an annular outer peripheral edge 13; and grindstone chips 30 disposed at predetermined intervals in a circumferential direction of the outer peripheral edge. The grindstone chip has a support part 31 and a cutting part 32 joined to one end surface of the support part and having a predetermined thickness. An edge 33AB formed by a side at which a front surface 34 of the cutting part and an upper surface 33 of the cutting part are connected is arranged so that its protruding length differs between the inner periphery side and the outer periphery side of the outer peripheral edge.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a grindstone and a grindstone tool that rotates to grind an object. [Background technology]

[0002] Rotary grinding wheels, which are used to remove coatings (urethane, lysine, elastic acrylic, epoxy, etc.) from the object of work, are mainly attached to rotary tools such as electric disc grinders and air grinders. It is known that the performance of these rotary grinding wheels (grinding amount per unit time, grinding amount continuity) varies depending on, for example, the width and number of grinding surfaces of sintered diamond chips (PCD: hereinafter referred to as chips), the amount of protrusion from the metal wheel, etc. In addition, the grinding amount per unit time and the grinding amount continuity of the grinding amount are evaluated by including grinding of the coating and the substrate of the coating (concrete, steel plate, etc.) (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-130414 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional grinding wheels use multiple tips with the same structure. Since the hard base of the coating, such as concrete, is in close contact with the coating, the cutting parts of the tips inevitably come into contact with the coating, causing the cutting parts to wear out more than necessary. As a result, the grinding performance of the grinding wheel is significantly reduced, and the grinding wheel itself must be replaced from the tool machine, which is uneconomical.

[0005] The present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide a grinding wheel and a grinding wheel tool that are capable of sustaining the grinding performance of the cutting portion. [Means for solving the problem]

[0006] In order to solve the above problems, the rotary grinding wheel according to the present invention comprises a cup-shaped base body having an annular outer periphery, and grinding chips arranged at a predetermined interval in the circumferential direction of the outer periphery. The grinding chips have a support part and a cutting part of a predetermined thickness joined to one end face of the support part, and an edge formed by a side connecting the front face of the cutting part and the upper face of the cutting part has a different protruding height on the inner side and the outer side of the outer periphery.

[0007] In order to solve the above problem, the rotary grinding wheel according to the present invention includes a cup-shaped base body having an annular outer peripheral edge, and grinding chips arranged at a predetermined interval in the circumferential direction of the outer peripheral edge. The grinding chip has a support part and a cutting part of a predetermined thickness joined to one end face of the support part. The grinding chip further includes a first grinding chip, the edge of which is formed by a side connecting the front surface of the cutting part and the upper surface of the cutting part, and has a different protruding height on the inner peripheral side and the outer peripheral side of the outer peripheral edge, and a second chip, the edge of which is formed by a side connecting the front surface of the cutting part and the upper surface of the cutting part, and has the same protruding height on the inner peripheral side and the outer peripheral side of the outer peripheral edge.

[0008] In order to solve the above-mentioned problems, the rotary grindstone tool of the present invention comprises the rotary grindstone described above, a rotating shaft that can be freely attached and detached to a base of the rotary grindstone, a drive unit that rotates the rotating shaft, and a housing unit that holds the drive unit and can be held by an operator with his or her fingers. Effect of the Invention

[0009] According to the present invention, it is possible to provide a grindstone and a grindstone tool that are capable of sustaining the grinding performance of the cutting portion. [Brief description of the drawings]

[0010] [Figure 1]1 is a perspective view showing a grinding wheel according to a first embodiment of the present invention; [Diagram 2] FIG. 2 is an enlarged view of part II in FIG. [Diagram 3] FIG. 2 is a front view of a cutting portion of a grinding wheel tip of the rotary grinding wheel according to the present invention. [Figure 4] FIG. 2 is a plan view showing the rotary grindstone according to the present invention. [Diagram 5] FIG. 2 is a side view showing the grindstone of the present invention. [Figure 6] FIG. 2 is an explanatory diagram showing a schematic state in which the rotary grindstone according to the present invention is used in a rotary grindstone tool. [Figure 7A] FIG. 4 is an explanatory view showing a schematic diagram of a difference in edge height between a first edge and a second edge of each grinding wheel tip of the rotary grinding wheel according to the present invention. [Figure 7B] FIG. 2 is an explanatory view showing a schematic comparison of the wear state of a first edge and a second edge in each grinding wheel tip of the rotary grinding wheel according to the present invention. [Figure 7C] FIG. 2 is an explanatory diagram showing a state in which a first edge of each grinding wheel tip of the rotary grinding wheel according to the present invention has been worn down to have a substantially equal height difference with a second edge. [Figure 8A] FIG. 2 is a front view showing a first modified example of the cutting portion of the grindstone tip according to the present invention. [Figure 8B] FIG. 11 is a front view showing a second modified example of the cutting portion of the grindstone tip according to the present invention. [Figure 8C] FIG. 11 is a front view showing a third modified example of the cutting portion of the grindstone tip according to the present invention. [Figure 8D] FIG. 11 is a front view showing a fourth modified example of the cutting portion of the grindstone tip according to the present invention. [Figure 8E] FIG. 13 is a front view showing a fifth modified example of the cutting portion of the grindstone tip according to the present invention. [Figure 8F] FIG. 13 is a front view showing a sixth modified example of the cutting portion of the grindstone tip according to the present invention. [Figure 8G] FIG. 13 is a front view showing a seventh modified example of the cutting portion of the grindstone tip according to the present invention. [Figure 8H] FIG. 13 is a front view showing an eighth modified example of the cutting portion of the grindstone tip according to the present invention. [Figure 9] FIG. 4 is a plan view showing a first modified embodiment of the grinding wheel according to the present invention. [Figure 10] FIG. 11 is a plan view showing a second modified embodiment of the grinding wheel according to the present invention. [Figure 11] FIG. 4 is a plan view showing a grinding wheel according to a second embodiment of the present invention. [Figure 12] FIG. 12 is an enlarged perspective view showing a schematic diagram of the grindstone tip used in FIG. 11. [Figure 13] 13 is a cross-sectional view taken along line XIII-XIII in FIG. 12. [Figure 14A] FIG. 11 is a plan view showing a grinding wheel according to a third embodiment of the present invention. [Figure 14B] FIG. 14B is an enlarged perspective view showing a schematic view of a portion indicated by XIVB in FIG. 14A. [Figure 14C] FIG. 14B is an enlarged perspective view showing a schematic view of a portion indicated by XIVC in FIG. 14A. [Figure 15A] FIG. 2 is an enlarged perspective view showing a schematic diagram of one grinding wheel tip used in the rotary grinding wheel in the embodiment according to the present invention. [Figure 15B] 15B is a cross-sectional view taken along line XVB-XVB in FIG. 15A. [Figure 15C] FIG. 4 is an enlarged perspective view showing a schematic diagram of the other grinding wheel tip used in the rotary grinding wheel in the embodiment according to the present invention. [Figure 15D] 15D is a cross-sectional view taken along line XVD-XVD in FIG. 15C. [Figure 16A] FIG. 2 is an enlarged perspective view showing a schematic diagram of one grinding wheel tip used in a rotary grinding wheel in a comparative example. [Figure 16B] 16B is a cross-sectional view taken along line XVIB-XVIB in FIG. 16A. [Figure 16C] FIG. 13 is an enlarged perspective view showing a schematic diagram of the other grinding wheel tip used in the rotary grinding wheel in the comparative example. [Figure 16D] 16D is a cross-sectional view taken along line XVID-XVID in FIG. 16C. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the rotary grindstone and rotary grindstone tool according to the present invention will be described with reference to the drawings. In the description based on the drawings, the same elements are given the same reference numerals, and duplicated description will be omitted. In the description of the rotary grindstone tool, the up-down direction of each element is described based on FIG. 1. In addition, in each drawing, the spacing and size of each component are exaggerated to make the description easier to understand. Furthermore, in each drawing, up-down, left-right, and up-down do not indicate absolute directions but are relative directions.

[0012] [Rotary grindstone] As shown in Figures 1 to 5, the rotary grinding wheel 100 comprises a cup-shaped base 10 and 3 to 16 (8 in the drawings) sintered diamond chips (hereinafter referred to as grinding wheel chips) 30 attached to the outer peripheral edge of the base 10 via a pedestal 20 that is elevated above the peripheral surface by a step. In the rotary grindstone 100, the grindstone tip 30 has a support portion 31 and a cutting portion 32 of a predetermined thickness joined to one end surface of the support portion 31. An edge 32AB formed by a side connecting an upper surface 35 of the cutting portion 32 and a front surface 34 of the cutting portion 32 is arranged so that the protruding height is different on the outer peripheral side and the inner peripheral side. Each component of the rotary grindstone 100 will be described below.

[0013] The base 10 is formed in the shape of a hollow truncated cone with a bottom, and is provided with a connection surface 11 for connecting a rotation shaft D1 of a rotating tool D described later in FIG. 6, a truncated cone-shaped side surface 12 arranged at an angle from the connection surface 11, and a circular ring-shaped outer circumferential edge 13 arranged at the end of the side surface 12. The connection surface 11 is disposed on one end side of the truncated cone-shaped side surface 12, and is a portion through which the rotary shaft D1 of the rotary tool D described later is inserted and detachably fixed to the rotary tool D via a mounting fixture. The connection surface 11 has a mounting hole 11a formed in the center for inserting the rotary shaft D1 of the rotary tool D. This connection surface 11 is integrally connected to the side surface 12. The outer shape (diameter) of the base body 10 used is, for example, φ95, φ125, φ150, etc., and is not particularly limited. The base body 10 may be made of metal or resin. Furthermore, the mounting hole 11a formed in the connection surface 11 may be formed as a screw hole, and the rotation direction and the screw fastening direction may be reversed, and there is no limitation as long as it can be attached to the rotary tool D and used.

[0014] The side surface 12 is formed from the connecting surface 11 into a truncated cone-shaped inclined surface, and has dust collection holes 12a for collecting dust formed at equal intervals in the circumferential direction. As an example, the side surface 12 has eight dust collection holes 12a formed therein. Each of the dust collection holes 12a is disposed so as to be located between the grinding chips 30 disposed in the circumferential direction. An annular outer peripheral edge 13 is disposed on the other end side of the side surface 12 and is integrally connected to the side surface 12. The number and size of the dust collection holes 12a are not particularly limited. The outer peripheral edge 13 is formed in a circular shape with a constant thickness and a constant width. The grindstone chips 30 are arranged at equal intervals on the circumferential surface of the outer peripheral edge 13. As an example, the outer peripheral edge 13 has pedestals 20 arranged at equal intervals protruding from the circumferential surface, and the grindstone chips 30 are attached to the pedestals 20. As an example, the pedestals 20 are arranged at eight locations in the circumferential direction of the outer peripheral edge 13.

[0015] The base 20 is an attachment portion for the grinding chip 30, and is formed to protrude in the height direction from the peripheral surface of the outer periphery 13. The base 20 is formed so as to protrude from the peripheral surface by the same width as the width of the outer periphery 13, with the rising surface 21 rising from four directions, front, back, left and right. The base 20 has the rising surface 21 and a mounting surface 22 continuous with one end of the rising surface 21, and the chip is disposed on the mounting surface 22. The base 20 has a recess 23 in the mounting surface 22 for mounting the grinding chip 30, and here, the grinding chip 30 is joined to the recess 23 so as to protrude by a predetermined amount.

[0016] The recess 23, which is the mounting surface 22, is formed eccentrically from the center to the outside on the mounting surface 22 so that the outer edge side of the outer periphery 13 is open in a plan view. The recess 23 has a recess such that the cutting portion 32 of the grindstone chip 30 is higher than the support portion 31 at a predetermined angle and is inclined. In other words, the recess 23 is formed so that the recess becomes deeper from one end side to the other end side, and the outer edge side is opened. Therefore, when the grindstone chip 30 is joined to the recess 23, the grindstone chip 30 is inclined at a predetermined angle and a part of the grindstone chip 30 protrudes outward from the width of the outer periphery 13 by a width W (see FIG. 5). In addition, since the grindstone chip 30 is arranged inclined in the recess 23, it is joined in a posture in which the first edge 32A3 of the cutting portion 32 is at the highest position.

[0017] As an example, a plurality of grindstone tips 30 (eight in the drawing) are arranged at regular intervals. Here, the grindstone tips 30 are of the same shape. The grindstone tips 30 are provided with a block-shaped support part 31 made of ultra-high strength steel, and a cutting part 32 made of polycrystalline synthetic sintered block diamond with a predetermined thickness on one end surface of the support part 31. The support part 31 and the cutting part 32 are integrally joined, and the cutting part 32 is configured to be thinner than the support part 31. The cutting part 32 has an edge 32AB formed by the sides connecting the upper surfaces 32A1, 32B1 of the cutting part 32 to the front surfaces 32A2, 32B2 of the cutting part 32. The cutting part 32 has a first edge 32A3 and a second edge 32B3 through a groove part 33 in the center as the edge 32AB. The groove portion 33 is formed in a V-shape, for example, and is formed across the cutting portion 32 and the support portion 31 of the grindstone tip 30.

[0018] The first edge 32A3 is formed by a side connecting the upper surface 32A1 of the cutting portion 32, which is on the outer edge side of the outer periphery 13, and the front surface 32A2 of the cutting portion 32 across the groove portion 33. The second edge 32B3 is formed by a side connecting the upper surface 32B1 of the cutting portion 32, which is on the inner edge side of the outer periphery 13, and the front surface 32B2 of the cutting portion 32 across the groove portion 33. The first edge 32A3 is formed to be higher than the second edge 32B3, with a different height from the second edge 32B3.

[0019] The height of the cutting part 32 is adjusted so that when the first edge 32A3 comes into contact with the object M (see FIG. 6) and is worn down due to wear, causing a decrease in grinding performance, the second edge 32B3 comes into contact with the object M. The difference in height between the first edge 32A3 and the second edge 32B3 is set, for example, in the range of 0.05 mm to 0.5 mm. Furthermore, the difference in height is more preferably 0.1 mm to 0.3 mm. It is preferable that the edge width of each of the first edge 32A3 and the second edge 32B3 is 1.2 mm or more, for example. If the edge width is 1 mm or less, the edge is likely to be damaged in a short time during grinding, and the grinding state may be extremely deteriorated. Therefore, the edge width is set to 1.2 mm or more, taking into account the safety factor.

[0020] Also, as an example, the first edge 32A3 and the second edge 32B3 are each formed of a straight side. That is, the first edge 32A3 is formed of a straight side that connects the upper surface 32A1 of the cutting portion 32, which is the outer edge side, to the front surface 32A2 of the cutting portion 32 via the groove portion 33. Also, the second edge 32B3 is formed of a straight side that connects the upper surface 32B1 of the cutting portion 32, which is the inner edge side, to the front surface 32B2 of the cutting portion 32 via the groove portion 33. Furthermore, the protruding heights of the first edge 32A3 and the second edge 32B3 (hereinafter referred to as "edge heights") are height dimensions that make the second edge 32B3 effective for grinding the object M when the edge portion of the first edge 32A3 wears and the grinding performance decreases. For example, when the first edge 32A3 is 2.0 mm from the lower surface of the grinding tip 30, the difference is set to 0.2 mm so that the second edge 32B3 is 1.8 mm from the lower surface of the grinding tip 30. If the difference in edge heights is in the range of 0.15 mm to 0.25 mm, the grinding performance is maintained without excessive deterioration.

[0021] As shown in Fig. 6, the rotary grindstone 100 is used as a rotary grindstone tool 200 attached to a rotary tool D. The rotary grindstone tool 200 includes the rotary grindstone 100, a rotary shaft D1 detachably attached to the base 10 of the rotary grindstone 100, a drive unit D2 that rotates the rotary shaft D1, and a housing unit D3 that holds the drive unit D2 and can be held by an operator. The rotary grindstone 100 is used as the rotary grindstone tool 200 by an operator holding and operating the housing unit D3 of the rotary tool D by inserting the rotary shaft D1 of the rotary tool D into the mounting hole 11a of the connection surface 11, bringing the grindstone tip 30 of the outer circumferential edge 13 of the base 10 into contact with the surface of the object M to be ground, and driving the drive unit D2 of the rotary tool D. In the rotary grindstone tool 200, the rotary grindstone 100 uses the edges 32AB of the eight grindstone tips 30 to grind the surface of the object M to be ground. As described above, the rotary grindstone 100 is configured so that each cutting portion 32 has a first edge 32A3 and a second edge 32B3 with different heights. Therefore, it is possible to improve the grinding performance so that it can be sustained, compared to grindstone tips with only one type of edge height. The grindstone chip 30 is disposed so that a part of the cutting portion 32, specifically, a part of the first edge 32A3, protrudes from the width of the outer peripheral edge, but the position of the recess 23 of the base 20 may be adjusted so that it fits within the width of the outer peripheral edge 13. The recess 23 is formed so that the outer peripheral side is open, but the outer peripheral side may be closed.

[0022] The grinding wheel 100 is configured so that the edge height varies for each grinding tip 30, and as grinding proceeds, it becomes as shown in Figures 7A to 7C. Note that in Figure 7, the grinding tip 30 shown on the right side is shown as a reference, unworn state. First, as shown in FIG. 7A, the surface of the object M is ground by the first edge 32A3 having the highest edge height, with an edge difference T1 being the height difference between the first edge 32A3 and the second edge 32B3. Then, as shown in FIG. 7B, the first edge 32A3 becomes worn to have an edge difference T2, and the edge height decreases due to the wear. Furthermore, as shown in Fig. 7C, the edge 32B1 drops to a height equivalent to that of the second edge 32B3, resulting in no edge difference such as the edge difference T3. When there is no edge difference in this manner, the second edge 32B3 mainly grinds the object M. Therefore, as shown in Fig. 7C, as the first edge 32A3 wears down, the grinding role that was previously mainly played by the first edge 32A3 is now taken over by the second edge 32B3.

[0023] During use, the grindstone 100 cannot work by contacting only the object M to be ground, but also comes into contact with the base material BN such as hardened concrete as shown in FIG. 6, and in that case, the edge 32AB of the cutting part 32 also wears quickly. However, because the heights of the edges 32AB are different, when the first edge 32A3 is in contact with the object M to grind, it does not come into contact with the second edge 32B3. Therefore, when grinding the object M, the grinding performance is maintained until the first edge 32A3 is worn to a certain extent. Furthermore, when the first edge 32A3 wears and the grinding performance decreases, the second edge 32B3 comes into contact with the object M to be ground, compensating for the decrease in the grinding performance of the first edge 32A3, and the decrease in the grinding performance can be improved and maintained.

[0024] In addition, when the first edge 32A3 is worn and the tip portion is rounded, the sliding property increases when the object M to be ground comes into contact with the first edge 32A3. Therefore, it becomes possible to maintain a good contact state with the object M when grinding, and the grinding performance can be sustained compared to the case where only the second edge 32B3 is used for grinding. Furthermore, since the seats 20 are formed at predetermined equal intervals on the outer peripheral edge 13 of the grindstone 100, the peripheral surface of the outer peripheral edge 13 and the object M can be prevented from contacting each other over the entire surface.

[0025] Moreover, according to the rotary grindstone 100, the grindstone tip 30 is provided with the first edge 32A3 and the second edge 32B3 of different heights, and the grindstone tip 30 is attached to the recess 23, so that the edge height, which is the protruding amount of the first edge 32A3 and the second edge 32B3, can be adjusted by appropriately determining the recess depth. Therefore, by providing the base 20 and the recess 23 of the same shape, all the attached grindstone tips 30 have the same configuration, and the structure of the first edge 32A3 and the second edge 32B3 of different heights can be realized in the cutting part 32, so that the manufacturing cost can be reduced.

[0026] Although an example of a preferred embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and each element can be appropriately modified in design within the scope of the gist of the present invention. In addition, the above invention-specific matters define the minimum necessary components, and other components may be added as long as they do not impair the effects of the invention.

[0027] In addition, the grindstone tip 30 has been described as having the configuration shown in Fig. 2 and Fig. 3, but may have the configuration shown in Fig. 8A to Fig. 8H, for example. Note that only the different parts in each configuration of the grindstone tip 30 already described will be described, and the description of the other parts will be omitted. 8A, the grindstone tip 30A may have a groove 33A disposed between the first edge 32A3a and the second edge 32B3a, which is a rectangular groove. When the groove 33A is rectangular, each surface connected to the first edge 32A3a and the second edge 32B3a rises at 90 degrees to form the first edge 32A3a and the second edge 32B3a.

[0028] 8B, the grindstone tip 30B may have a groove 33B disposed between the first edge 32A3b and the second edge 32B3b in a U-shape. The U-shape of the groove 33B makes it easier to relieve stress on the groove portion, reducing the possibility of breakage. Furthermore, as shown in FIG. 8C, the grindstone tip 30C may be configured such that a first edge 32A3c having a low edge height is arranged on the outer edge side of the outer periphery 13, and a second edge 32B3c having a high edge height is arranged on the inner edge side of the outer periphery 13.

[0029] As shown in FIG. 8D, the grindstone tip 30D has a curved portion 32A4 in a part of the straight line where the first edge 32A3d is on the outer edge side. In addition, the groove portion 33D separating the first edge 32A3d and the second edge 32B3d is configured to have a large V-shape with an angle exceeding 90 degrees. Since the first edge 32A3d has the curved portion 32A4 in a part of the straight line, the contact area is smaller compared to a configuration in which the width of the straight line portion is entirely straight. Therefore, the first edge 32A3d has improved sharpness during grinding compared to a configuration in which the entire portion is entirely straight. In addition, the rotary grindstone equipped with the grindstone tip 30D is less likely to get caught when moving the rotary grindstone during grinding work, making it easier to move.

[0030] As shown in FIG. 8E, the grinding tip 30E has a first edge 32A3e that is curved and is formed by a side that connects the upper curved surface 32A1e and the front surface 32A2e of the cutting portion 32E. Similarly, the second edge 32B3e has a curved shape and is formed by a side that connects the upper curved surface 32B1e and the front surface 32B2e of the cutting portion 32E. The groove portion 33E that divides the first edge 32A3e and the second edge 32B3e is a gently curved recessed groove. Since the first edge 32A3e and the second edge 32B3e are curved, the length of the side that contacts the object M to be ground is initially smaller than that of a straight edge, and the sharpness of grinding is improved.

[0031] Furthermore, as shown in Fig. 8F, the grindstone tip 30F may be configured such that the first edge 32A3f and the second edge 32B3f are adjacently arranged without a groove. Although the first edge 32A3f and the second edge 32B3f are formed in a straight line, they may be formed in a gently curved line that is convex upward (see Fig. 8E). Also, the straight line may be partially curved.

[0032] As shown in FIG. 8G, the grindstone chip 30G includes a first edge 32A3g, a second edge 32B3g, a third edge 32C3g, and a fourth edge 32D3g. As shown in FIG. 9, the grindstone chip 30G is arranged over the entire width of the outer peripheral edge 13. The grindstone chip 30G is arranged so that the first edge 32A3g to the fourth edge 32D3g are aligned from the outer edge side to the inner edge side of the outer peripheral edge 13. The grindstone chip 30G is preferably arranged so that it has an angle θ of several degrees (see FIG. 9) with respect to a reference line virtually drawn from the center of the base 10 to the outer peripheral edge 13. For example, the grindstone chip 30G is arranged so that it has an angle θ of 5 degrees or more and 45 degrees or less, and preferably the angle θ is 5 degrees or more and 15 degrees or less. In FIG. 9, the grindstone chip 30G is arranged so that it has an angle θ of 7 degrees, as an example.

[0033] In the grindstone tip 30G, for example, the second edge 32B3g and the fourth edge 32D3g have the same edge height, and the first edge 32A3g and the third edge 32C3g have the same height. The second edge 32B3g and the fourth edge 32D3g are set to have higher edge heights than the first edge 32A3g and the third edge 32C3g. Here, as an example, the grindstone tips 30G are arranged with the same configuration in the circumferential direction.

[0034] In addition, in the grinding wheel chip 30G, if the first edge 32A3g and the third edge 32C3g have the same height and the second edge 32B3g and the fourth edge 32D3g have the same height, the second group having an edge height higher than the first group may be placed next to the first group having an edge height higher than the second group, and the first and second groups may be placed alternately in the circumferential direction. In addition, in the grindstone chip 30G, if the height of the edge is different, for example, only one edge with a different height may be provided, and the arrangement of the edges with different heights may be changed in sequence from the outer edge side to the inner edge side in the circumferential direction. Furthermore, for example, in the grindstone chip 30G, if the height of the edges is changed to be different every two, the higher edge may be arranged alternately on the outer edge side and the higher edge may be arranged on the inner edge side in the circumferential direction.

[0035] Next, as shown in FIG. 8H, the grindstone tip 30H has a first edge 32A3h and a second edge 32B3h via a groove portion 33H. The grindstone tip 30H is disposed over the entire width of the outer peripheral edge 13 as shown in FIG. 9, for example. The first edge 32A3h and the second edge 32B3h are configured to have a width narrower than the width of the groove portion 33H. The first edge 32A3h is configured to be higher than the second edge 32B3h. The groove portion 33H is configured in the shape of a trapezoidal groove with the sides toward the first edge 32A3h and the second edge 32B3h as oblique sides.

[0036] In this way, the grindstone tip 30H has a groove 33H wider than the width of the edge, so that the member continuing to the first edge 32A3h and the second edge 32B3h has a wide area, and the width of the edge can be narrowed. Therefore, it is possible to improve the sharpness of the cutting edge while making the first edge 32A3h and the second edge 32B3 less likely to be damaged. In addition, the grindstone tip 30H may be configured so that the height of the second edge 32B3h is higher than the height of the first edge 32A3h.

[0037] The grindstone tips 30H may all be arranged in the circumferential direction of the outer peripheral edge 13 with the same configuration. The grindstone tips 30H may also be arranged in the circumferential direction so that the edge heights change alternately between the outer peripheral side and the inner peripheral side. The grindstone tips 30H may be arranged in the circumferential direction so that the edge heights change between the outer peripheral side and the inner peripheral side with every two, three, or four, with the total number of the grindstone tips being in the range of 6 to 16. The grindstone chip 30H is disposed at a predetermined angle θ (see FIG. 9) with respect to the reference line, similarly to the grindstone chip 30G. The grindstone chips 30A to 30E may be configured so that the widths of the grooves 33A to 33E are widened like the grindstone chip 30H, and disposed as shown in FIG.

[0038] Although not shown, the grindstone chip may have three edges, a first edge, a second edge, and a third edge, and may be arranged as shown in FIG. 9. Each grindstone chip 30A-30H shown in FIG. 8A to FIG. 8H may be arranged in a circumferential direction in the outer peripheral edge 13, with the inner peripheral side being high and the outer peripheral side being low, and the outer peripheral side being high and the inner peripheral side being low. The grindstone chips 30A-30H may be arranged so that the inner peripheral side is high and the outer peripheral side is low, or the outer peripheral side is high and the inner peripheral side is low, every other chip, every third chip, or every third chip. Furthermore, the grindstone chips may be arranged by repeating one chip with a high outer peripheral side and two chips with a high inner peripheral side, or by combining one chip with a high inner peripheral side and two chips with a high outer peripheral side, or by repeating two chips with a high outer peripheral side and three chips with a high inner peripheral side, or by repeating two chips with a high inner peripheral side and three chips with a high outer peripheral side.

[0039] As described above, the rotary grindstone 100 may have the grindstone tips 30A-30H as shown in Fig. 8A to Fig. 8H and Fig. 9, and the number of attachment points of the grindstone tips 30, 30A-30H is not limited to eight, and the grindstone tips 30, 30A-30H may be attached so as to realize different heights of the edges 32AB, and may be attached at three to sixteen locations, so that edges 32AB of different heights can be attached appropriately to one grindstone tip 30. Also, the rotary grindstone 100 may have a configuration in which two or more types of grindstone tips 30, 30A-30H are combined and arranged at equal intervals in the circumferential direction of the outer circumferential edge 13.

[0040] For example, the rotary grinding wheel 100 may be configured such that a first grinding wheel tip having a first edge at a first height and a second edge at a second height is a first group, a second grinding wheel tip having a second edge at a second height and a third edge at a third height is a second group, and a third grinding wheel tip having a third edge at a third height and a fourth edge at a fourth height is a third group. The difference in edge height between the first edge and the second edge and other configurations have already been described, and similarly, the difference in edge height between the second edge and the third edge and other configurations, and the difference in edge height between the third edge and the fourth edge and other configurations are equivalent to the relationship between the first edge and the second edge. In the rotary grinding wheel 100, the grinding chips may be arranged in a range of 3 to 16 locations at equal intervals in the circumferential direction by either the first group of 3 chips, the second group of 4 chips, or the third group of 5 chips, or by combining any of them. Of course, all of the grinding chips in the 3 to 16 locations may be configured as one of the grinding chips 30, 30A to 30H. When different types of grinding chips are arranged, the first and second edges of the same type may have different heights, and when different types are combined, the heights of the first edges and second edges of different types may be the same, or the heights of the first edges and second edges may be different between different types.

[0041] In addition, the arrangement of the grinding stone chips 30, 30A to 30H may be, for example, such that the multiple first grinding stone chips arranged on the outer edge side of the outer periphery 13 and the multiple second grinding stone chips arranged on the inner edge side of the outer periphery 13 are alternately spaced one apart or every two apart, or alternately spaced one apart or every three apart, or alternately spaced two apart or every three apart, etc. Furthermore, as shown in FIG. 10, the rotating grinding wheel may include a plurality of first grinding wheel chips A30 arranged circumferentially on the outer edge side of the outer circumferential edge 13, and a plurality of second grinding wheel chips B30 arranged circumferentially on the inner edge side of the outer circumferential edge 13, and at least one of the first grinding wheel chips A30 and at least one of the second grinding wheel chips B30 may be arranged in a predetermined arrangement as group GA1, with the groups GA1 being equally spaced circumferentially.

[0042] In Fig. 10, the first grindstone chips A30 arranged on the outer edge side are arranged in pairs at regular intervals. The second grindstone chips B30 arranged on the inner edge side are arranged one by one between the first grindstone chips A30 arranged in pairs. The group GA1 is composed of two first grindstone chips A30 and one second grindstone chip B30, and the group GA1 is arranged in the circumferential direction at regular intervals. The first grindstone chip A30 and the second grindstone chip B30 may be any of the grindstone chips 30, 30A to 30H already described. In addition, in Fig. 10, the width in the diameter direction of the first grindstone chip A30 is shown to be larger than the width in the diameter direction of the second grindstone chip B30, but the widths in the diameter direction may be the same or one may be larger.

[0043] Next, a second embodiment and a third embodiment of the present invention will be described with reference to Fig. 11 to Fig. 14C. Note that in the second and third embodiments, only the parts different from the first embodiment will be described, and the same components as those already described will be denoted by the same reference numerals and will not be described. The grinding wheel 100A of the second embodiment differs from the first embodiment in that the base 20 is not provided on the outer peripheral edge 13, and the grinding wheel tip 30 is joined by a joining means such as brazing through a recess 14 provided on the outer peripheral edge 13. The grinding wheel tip 30 has the configuration already described, and is arranged so that a part of it protrudes outward from the outer peripheral edge 13 (see symbol W in FIG. 5). When such a grinding wheel 100A is attached to a rotary tool D as shown in FIG. 6 and an object M is ground, as already described, even if the first edge 32A3 is worn, the object M can be ground by the second edge 32B3, and grinding performance can be maintained for a long time compared to the conventional configuration.

[0044] Next, as shown in Fig. 14A to Fig. 14C, a third embodiment according to the present invention will be described. In the third embodiment, the rotary grindstone 100B includes a cup-shaped base body 10B having an annular outer peripheral edge 13, a first grindstone chip 40 on the outer peripheral side, and a second grindstone chip 30 on the inner peripheral side, which are grindstone chips arranged at a predetermined interval in the circumferential direction of the outer peripheral edge 13. The second grindstone chip 30 has the same configuration as the grindstone chip 30 in Fig. 11 already described, except for the arrangement. In addition, the first grindstone chip 40 and the second grindstone chip 30 are arranged in a group GB1 that is equivalent to the group GA1 already described in Fig. 10, in terms of their circumferential arrangement. In other words, in this rotary grindstone 100B, the configuration of the first grindstone chip 40 is different.

[0045] The first grindstone tip 40 includes a block-shaped support portion 41 and a cutting portion 42 disposed on one end surface of the support portion 41, and is formed in a substantially rectangular parallelepiped shape. The first grindstone tip 40 has an edge 42C formed by an edge connecting an upper surface 42A of the cutting portion and a front surface 42B of the cutting portion 42. The edge 42C has the same protruding height on the inner and outer peripheral sides of the outer circumferential edge 13. The first grindstone tip 40 has the edge 42C brazed and welded into the recess 15, and is disposed so that the edge 42C protrudes upward from the edge surface of the outer circumferential surface 13. The edge 42C of the first grindstone tip and the first edge 32A3 of the second grindstone tip 30 are disposed to have the same height. The size of the width direction of the outer peripheral surface 13 of the first grindstone tip 30 is smaller than that of the second grindstone tip 30, and is preferably within a range of, for example, (4 / 8) to (6 / 8) of the width direction of the second grindstone tip.

[0046] As an example, the rotary grindstone 100B has five groups GB1 in the circumferential direction, each group GB1 including two first grindstone tips 40 and one second grindstone tip 30. The rotary grindstone 100B is arranged so that the groups GB1 are equally spaced in the circumferential direction. The rotary grindstone 100B is attached to the rotary tool D already described in FIG. 6 to perform grinding work. At the beginning of grinding, the rotary grindstone 100B grinds the object M with the edge 43 of the first grindstone tip 40 and the first edge 32A3 of the second grindstone tip 30, and when the edge 43 of the first grindstone tip 40 and the first edge 32A3 of the second grindstone tip 30 are worn, the second edge 32B3 of the second grindstone tip 30 functions mainly in the grinding operation. Therefore, it is possible to maintain the grinding performance for a longer period of time compared to the conventional rotary grindstone tool.

[0047] In addition, in the rotating grindstone 100A shown in Fig. 11, the grindstone tips 30A to 30H described in Fig. 8A to 8H can be used, and the arrangement and configuration shown in Fig. 9 and Fig. 10 can also be used. In addition, in the rotating grindstone 100B shown in Fig. 14A to Fig. 14C, the second grindstone tip can be the grindstone tip 30A to 30H described in Fig. 8A to Fig. 8H. In addition, in the rotating grindstones 100A and 100B, the grindstone tip may be disposed via the recess 24 of the base 20. Furthermore, the first grinding wheel chips 40 shown in Figure 14B may be made to be the same height as the first edge 32A3 of the second grinding wheel chip 30, and may be made to be the same height as the second edge 32B3, and the first grinding wheel chips 40 of different heights may be arranged alternately in the circumferential direction in group GB1. EXAMPLES

[0048] Next, a comparison between a conventional grinding wheel and the grinding wheel of the present invention will be described as an example with reference to Figures 15A to 15D, 16A to 16D, and Table 1. Note that the example shown here is merely an example, and the present invention is not limited to this example. First, the configuration of an embodiment of the present invention will be described with reference to FIG. 1 and FIGS. 15A to 15D. In the rotary grinding wheel 100 according to the embodiment, the grinding wheel chips 30 and grinding wheel chips 30C, which have already been described, are alternately arranged at eight locations in the circumferential direction of the outer peripheral edge 13. The base body 10 used has an outer diameter of φ95 mm. In addition, the outer peripheral edge 13 is formed with a recess 14 for joining the grinding wheel chips 30 and 30C. This recess 14 is formed so that when the grinding wheel chips 30 and 30C, each having a width of 5 mm, a height of 2 mm, and a thickness of 3.2 mm, are arranged, the amount of protrusion from the peripheral surface is 1 mm.

[0049] Furthermore, the grindstone tip 30 is formed so that the first edge 32A3 and the second edge 32B3 each have a diameter width of 1.5 mm and a height difference of 0.2 mm. The grindstone tip 30C is formed so that the first edge 32A3c and the second edge 32B3c each have a diameter width of 1.5 mm and a height difference of 0.2 mm. 16A to 16D, the grindstone according to the comparative example has recesses 14 formed in the circumferential direction on the outer periphery 13 of the base 10 similar to that of the embodiment, and grindstone tips 130 are arranged in eight locations. The grindstone tips 130 according to the comparative example are brazed and welded to the recesses 14 so that the width of the edge 132A3 is 1.5 mm and the amount of protrusion from the circumferential surface is 1 mm. The edges 132A3 are alternately arranged in the circumferential direction so that they are located on the outer edge side and the inner edge side in the circumferential direction. The object M to be ground was the surface of sandy concrete (strength 24N), and the grinding wheel 100 of the embodiment and the grinding wheel 130 of the comparative example were attached to an electric disc grinder, and grinding work was performed with a load of 3 kg (about 29.4 N). Table 1 shows the grinding performance, which compares the amount of grinding powder from the ground object M.

[0050] [Table 1]

[0051] Comparing the grinding amounts every 60 minutes, it can be seen that the grinding amount of the grinding wheel tip 30 of the rotary grinding wheel 100 of the embodiment is 10% or more greater than that of the grinding wheel tip 130 of the rotary grinding wheel of the comparative example. In addition, it was confirmed that the difference in the grinding amount of the rotary grinding wheel 100 of the embodiment becomes larger as the grinding time elapses compared to the rotary grinding wheel of the comparative example, and that the rotary grinding wheel 100 of the embodiment is also superior in durability. In this way, the grindstone 100 and grindstone tool 200 according to the present invention can maintain grinding performance by using the grindstone tips 30, 30A to 30H, etc. The grindstone tips 30, 30A to 30H may all be the same as any of the grindstone tips 30, 30A to 30H, as long as they are arranged at 3 to 18 (preferably 16) locations on the outer peripheral edge 13. The grindstone tips 30, 30A to 30H may be arranged so that two types of the grindstone tips are arranged at equal intervals in the circumferential direction, three types of the grindstone tips are arranged at equal intervals in the circumferential direction, or four types of the grindstone tips are arranged at equal intervals in the circumferential direction. The grindstone tips 30, 30A to 30H may be arranged at 3 to 18 (preferably 16) locations, and the number of types arranged at equal intervals in the circumferential direction may be changed. When arranging the edges of different types, the configuration of the second edge having a different height from the first edge may be the same as that of the first edge, or the height of the edge may be changed for each type without changing the configuration of the second edge having a different height from the first edge. [Explanation of symbols]

[0052] 10 Base 11 Connection surface 11a Mounting hole 12 Side 12a Dust collection hole 13 Outer rim 14, 23 Recess 20 Pedestal 21 Standing surface 22 Mounting surface 30, 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H Grindstone Tip 31 Support part 32A1, 32B1, 34 Top 32A2, 32A2e, 32B2e, 32B2, 33 Front 32, 32A, 32B, 32C, 32D, 32E, 32F, 32G, 32H cutting part 32A3, 33A3, 32A3a, 32A3b, 32A3c, 32A3d, 32A3e, 32A3f, 32A3g, 32A3h 1st edge 32B3, 33B3, 32B3a, 32B3b, 32B3c, 32B3d, 32B3e, 32B3f, 32B3g, 32B3h Second Edge 32A1e Upper curved surface 32B1e Upper curved surface 32C3g 3rd Edge 32D3g 4th Edge 33, 33A, 33B, 33C, 33D, 33E, 33G1, 33G2, 33G3, 33H Groove 34 Front (front of cutting part) 35 Top surface (top surface of cutting part) 100, 100A Rotary Grindstone 200 Rotary grinding tools A30, 40 No. 1 grinding wheel tip B30, 30 2nd grinding wheel tip D Rotary tools D1 Rotational axis D2 Drive unit D3 housing GA1 Group M Object T1 Edge Difference T2 Edge Difference T3 Edge Difference W width

Claims

1. A cup-shaped base body having an annular outer periphery; and grindstone chips arranged at predetermined intervals in the circumferential direction of the outer circumferential edge, The grinding wheel tip has a support portion and a cutting portion of a predetermined thickness joined to one end surface of the support portion, and an edge formed by an edge connecting the front surface of the cutting portion and the upper surface of the cutting portion has a protruding height that differs between the inner side and the outer side of the outer periphery.

2. 2. The grindstone according to claim 1, wherein the edges of the cutting portions are each formed of linear sides connecting the upper surfaces of the cutting portions and the front surfaces of the cutting portions, the upper surfaces being at different heights.

3. 2. The grinding wheel according to claim 1, wherein each edge of the cutting portion is formed by a curved side connecting a flat curved surface of the cutting portion and a front surface of the cutting portion, the flat curved surface having a different height from each other.

4. 2. The grindstone according to claim 1, wherein the edge of the cutting portion has a curved portion at one end or the other end of a linear portion having a different height.

5. The grinding wheel according to claim 1 , wherein the grinding chips are arranged in such a manner that, at the outer periphery, the edges are higher on the inner periphery side and lower on the outer periphery side, and the edges are higher on the outer periphery side and lower on the inner periphery side in the circumferential direction.

6. 2. The grindstone according to claim 1, wherein the edges of the cutting portion are arranged at different heights via grooves.

7. The rotary grindstone according to claim 1 , wherein the grindstone chips are disposed via pedestals that protrude from the peripheral surface of the outer periphery.

8. The grinding wheel of claim 1, wherein the grinding wheel chips are arranged on the outer peripheral edge in a total number ranging from 3 to 16, and are arranged at equal intervals in the circumferential direction with the same edge configuration, either alone or in a first group of 3 chips, a second group of 4 chips, or a third group of 5 chips, so as to satisfy the total number range, and the first, second and third groups each include the grinding wheel chips having different edge heights.

9. The grindstone chips include a plurality of first grindstone chips arranged on an outer edge side of the outer circumferential edge, and a plurality of second grindstone chips arranged on an inner edge side of the outer circumferential edge, The grinding wheel according to claim 1 , wherein at least one of the first grinding wheel tips and at least one of the second grinding wheel tips are arranged in a group in a preset arrangement, and the groups are arranged at equal intervals in the circumferential direction.

10. A cup-shaped base body having an annular outer periphery; and grindstone chips arranged at predetermined intervals in the circumferential direction of the outer circumferential edge, The grindstone tip has a support portion and a cutting portion of a predetermined thickness joined to one end surface of the support portion, a first grinding tip having an edge formed by a side connecting a front surface of the cutting portion and an upper surface of the cutting portion, the edge having a different protruding height on an inner peripheral side and an outer peripheral side of the outer circumferential edge; A rotary grinding wheel having an edge formed by a side connecting the front surface of the cutting portion and the upper surface of the cutting portion, and a second tip having the same protruding height on the inner and outer peripheral sides of the outer circumferential edge.

11. A rotary grindstone tool comprising: the rotary grindstone according to any one of claims 1 to 10; a rotating shaft that is detachably attached to a base body of the rotary grindstone; a drive unit that rotates the rotating shaft; and a housing unit that holds the drive unit and can be held by an operator with his or her fingers.

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