METAL-BONDED GRINDING WHEEL

Abstract

 There is provided a metal-bonded grinding stone including an abrasive grain layer in which a plurality of abrasive grains and a plurality of pores are dispersed in a metal bonding material, in which a porosity of the plurality of pores in the abrasive grain layer is 40% or more and 99% or less.

Description

Technical Field

[0001] One aspect of the present invention relates to a metal-bonded grinding stone in which a plurality of abrasive grains are dispersed in a metal bonding material.

Background Art

[0002] Patent Literature 1 discloses a conventional metal-bonded grinding stone. The metal-bonded grinding stone described in Patent Literature 1 includes communication pores in which a volume ratio of abrasive grains is 55 to 65% and a volume ratio of a metal bonding material is 35 to 45% in terms of volume ratio of the abrasive grains and the metal bonding material, and a volume ratio of the communication pores in the grinding stone is 25 to 35%.

Citation List

Patent Literature

[0003] Patent Literature 1: Japanese Unexamined Patent Publication No. H10-277948

Summary of Invention

Technical Problem

[0004] Since the metal-bonded grinding stone described in Patent Literature 1 includes continuous pores, it is possible to exhibit a self-sharpening action due to crushing or abrasion of the grinding stone. However, since a porosity of the continuous pores is 25 to 35%, the promotion of crushing or abrasion of the grinding stone is not sufficient, and it is difficult to maintain good sharpness.

[0005] One aspect of the present invention is to provide a metal-bonded grinding stone that can maintain good sharpness by appropriately exhibiting a self-sharpening action due to crushing or abrasion of a metal bonding material.

Solution to Problem

[0006] A metal-bonded grinding stone according to one aspect of the present invention includes an abrasive grain layer in which a plurality of abrasive grains and a plurality of pores are dispersed in a metal bonding material, in which a porosity of the plurality of pores in the abrasive grain layer is 40% or more and 99% or less. In the metal-bonded grinding stone, since the porosity of the plurality of pores in the abrasive grain layer is 40% or more and 99% or less, it is possible to appropriately exhibit the self-sharpening action due to crushing or abrasion of the metal bonding material while ensuring the strength of the abrasive grain layer. Therefore, good sharpness can be maintained.

[0007] Each of the plurality of pores may be formed in a spherical shape. In the metal-bonded grinding stone, since each of the plurality of pores is formed in a spherical shape, it is easy to control the strength of the abrasive grain layer and the self-sharpening cycle for exhibiting the self-sharpening action of the abrasive grain layer.

[0008] An average of sphericity of the plurality of pores may be 0.2 or more and 1.0 or less. In the metal-bonded grinding stone, since the average of the sphericity of the plurality of pores is 0.2 or more and 1.0 or less, it is easy to control the strength of the abrasive grain layer and the self-sharpening cycle for exhibiting the self-sharpening action of the abrasive grain layer.

[0009] The plurality of pores may include an interconnecting pore formed by communicating two or more pores. Since the metal-bonded grinding stone has the interconnecting pore formed by communicating two or more pores, the discharging property of the chip is improved, and it is possible to suppress clogging of the pores due to the chip.

[0010] The interconnecting pore may include two or more of the pores communicating with each other and having a pore diameter of 10 µm or more and 2,000 µm or less. In the metal-bonded grinding stone, since the interconnecting pore includes two or more pores communicating with each other and having a pore diameter of 10 µm or more and 2,000 µm or less, it is possible to secure the strength of the abrasive grain layer, to improve the discharging property of the chip, and to shorten the self-sharpening cycle due to crushing or abrasion around the interconnecting pore. Therefore, it possible to maintain high sharpness.

[0011] In order to reinforce the abrasive grain layer, a reinforcing portion provided in the interconnecting pore may be further provided. In the metal-bonded grinding stone, since the reinforcing portion for reinforcing the abrasive grain layer is provided in the interconnecting pore, the strength of the abrasive grain layer reduced by the interconnecting pore can be improved.

[0012] The reinforcing portion may be filled in at least a part of the interconnecting pore so as to be connected to at least a part of an inner surface of the abrasive grain layer forming the interconnecting pore. In the metal-bonded grinding stone, since at least a part of the interconnecting pore is filled with the reinforcing portion so as to be connected to at least a part of the inner surface of the abrasive grain layer forming the interconnecting pore, excessive crushing or abrasion around the interconnecting pore can be suppressed.

[0013] The reinforcing portion may contain a resin. In the metal-bonded grinding stone, since the reinforcing portion contains a resin, the reinforcing portion can be easily formed.

[0014] The plurality of pores may include an independent pore not communicating with the other pores. Since the metal-bonded grinding stone has the independent pore not communicating with the other pores, it is possible to appropriately exhibit the self-sharpening action due to crushing or the like of the metal bonding material while suppressing a decrease in strength of the abrasive grain layer.

[0015] An average pore diameter of the independent pore may be 2 µm or more and 100 µm or less. In the metal-bonded grinding stone, since the average pore diameter of the independent pore is 2 µm or more and 100 µm or less, it is possible to secure the strength of the abrasive grain layer and to shorten the self-sharpening cycle due to crushing or abrasion around the independent pore. Therefore, it possible to maintain high sharpness.

[0016] The plurality of pores may include a micropore having a pore diameter of 2 µm or more and 10 µm or less. In the metal-bonded grinding stone, since the plurality of pores include the micropore having a pore diameter of 2 µm or more and 10 µm or less, it is possible to promote fine crushing or abrasion of the metal bonding material. Therefore, it is easy to control the self-sharpening cycle for exhibiting the self-sharpening action of the abrasive grain layer.

[0017] A porosity of the micropore in the abrasive grain layer is 0.01% or more and 10% or less. In the metal-bonded grinding stone, since the porosity of the micropore in the abrasive grain layer is 0.01% or more and 10% or less, it is possible to promote fine crushing or abrasion of the metal bonding material while securing the strength of the abrasive grain layer.

Advantageous Effects of Invention

[0018] According to one aspect of the present invention, it is possible to maintain good sharpness by appropriately exhibiting a self-sharpening action due to crushing or abrasion of the metal bonding material.

Brief Description of Drawings

[0019] 

FIG. 1(a) is a plan view illustrating an example of a metal-bonded grinding stone of the present embodiment, and FIG. 1(b) is a front view of the metal-bonded grinding stone illustrated in FIG. 1(a).

FIG. 2 is a schematic end view illustrating a part of an abrasive grain layer taken along line II-II in FIG. 1(a).

FIG. 3 is a schematic end view illustrating a part of an abrasive grain layer of a modification, which corresponds to FIG. 2.

Description of Embodiments

[0020] Hereinafter, embodiments of one aspect of the present invention will be described in detail with reference to the drawings. Note that, in the following description, the same or corresponding elements are denoted by the same reference numerals, and redundant description is omitted.

[0021] As illustrated in FIGS. 1 and 2, a metal-bonded grinding stone 1 according to the present embodiment includes, as an example, a base metal 2 and an abrasive grain layer 3 fixed to the base metal 2. The metal-bonded grinding stone 1 is a wheel type metal bonded grinding stone in which an annular abrasive grain layer 3 is formed on a peripheral edge of a disk-shaped base metal 2. However, the shape, size, application, and the like of the metal-bonded grinding stone 1 are not particularly limited. In addition, the metal-bonded grinding stone 1 may not include the base metal 2 and may be formed only of the abrasive grain layer 3.

[0022] The abrasive grain layer 3 of the metal-bonded grinding stone 1 is configured by dispersing a plurality of abrasive grains 6 and a plurality of pores 7 in a metal bonding material 5.

[0023] The metal bonding material 5 holds the plurality of abrasive grains 6, and is formed of a metal material. As the metal material forming the metal bonding material 5, for example, a metal such as Ti (titanium), Cr (chromium), Fe (iron), Co (cobalt), Ni (nickel), Cu (copper), Ag (silver), Sn (tin), or W (tungsten), or an alloy containing at least a part of these metals is used. As the alloy, for example, a Cu-Ag-Ti alloy, a Cu-Sn-Ti alloy, a Ni-Cr alloy, or a Cu-Sn alloy is used.

[0024] As the abrasive grains 6, for example, super abrasive grains such as diamond and CBN are used. In addition, as the abrasive grains 6, for example, grains having any grain size between #325 to #30,000 can be used. For example, a filler such as white alundum (WA) or green carborundum (GC) may be added to the abrasive grain layer 3.

[0025] The plurality of pores 7 are holes formed in the abrasive grain layer 3. That is, the abrasive grain layer 3 is porous due to the plurality of pores 7. Some of the plurality of pores 7 are located on a surface of the abrasive grain layer 3, and the remaining of the plurality of pores 7 are located inside the abrasive grain layer 3. A porosity of the plurality of pores 7 in the abrasive grain layer 3 is 40% or more and 99% or less. Note that as the porosity of the plurality of pores 7 in the abrasive grain layer 3, a porosity capable of obtaining an appropriate self-sharpening cycle can be selected depending on the application or purpose. For example, the porosity may be 70% or more and 90% or less or may be 40% or more and 60% or less. The porosity of the plurality of pores 7 in the abrasive grain layer 3 is a percentage of proportion occupied by the plurality of pores 7 in the abrasive grain layer 3. The porosity of the plurality of pores 7 in the abrasive grain layer 3 can be, for example, a percentage of proportion of a total area of the plurality of pores 7 to an area of the abrasive grain layer 3 in an arbitrary cross section of the abrasive grain layer 3.

[0026] Each of the plurality of pores 7 is formed in a spherical shape. The spherical shape includes, in addition to a perfect spherical shape, various spherical shapes such as a flat spherical shape and a deformed spherical shape having irregularities. An average of sphericity of the plurality of pores 7 may be, for example, 0.2 or more and 1.0 or less, 0.5 or more and 1.0 or less, or 0.7 or more and 1.0 or less. The sphericity of the pores 7 is, for example, a ratio of the minimum diameter to the maximum diameter. That is, the sphericity of the pores 7 having the maximum diameter of 200 µm and the minimum diameter of 100 µm is 0.5. The average of the sphericity of the plurality of pores 7 can be, for example, an average of the sphericity of each of the plurality of pores 7 exposed to an arbitrary cross section of the abrasive grain layer 3. In this case, since some of the pores 7 exposed to an arbitrary cross section of the abrasive grain layer 3 are cut out by the cross section, for example, the sphericity may be measured by interpolating the shape of the portion cut out from the shape of the remaining portion. Various known methods can be adopted as the interpolation.

[0027] The plurality of pores 7 include an interconnecting pore 71 formed by communicating two or more pores 7. That is, the interconnecting pore 71 is formed of two or more pores 7 communicating with each other. The abrasive grain layer 3 has a plurality of interconnecting pores 71. The interconnecting pore 71 is formed, for example, by partially overlapping adjacent pores 7. In this case, for example, the sphericity of each of the pores 7 constituting the interconnecting pore 71 may be measured by interpolating a shape of a portion overlapping an adjacent pore 7 from a shape of a portion not overlapping the adjacent pore 7 with an arc. The number of the pores 7 constituting the interconnecting pore 71 is not particularly limited. The interconnecting pore 71 may include pores 7 having a pore diameter that can obtain an appropriate self-sharpening cycle depending on the application or purpose. For example, the interconnecting pore 71 may include two or more pores 7 communicating with each other and having a pore diameter of 10 µm or more and 2,000 µm or less, may include two or more pores 7 communicating with each other and having a pore diameter of 10 µm or more and 1,000 µm or less, and may include two or more pores 7 communicating with each other and having a pore diameter of 10 µm or more and 100 µm or less. The pore diameters of two or more pores 7 constituting the interconnecting pore 71 can be determined, for example, by interpolating a shape of a portion overlapping an adjacent pore 7 in each pore 7 of the interconnecting pore 71 exposed to an arbitrary cross section of the abrasive grain layer 3 with an arc and measuring a pore diameter of each pore 7. The pore diameter of each pore 7 can be, for example, the maximum diameter of the pore 7.

[0028] The plurality of pores 7 include an independent pore 72 not communicating with the other pores 7. The independent pore 72 is constituted by one pore 7. The abrasive grain layer 3 has a plurality of independent pores 72. An average pore diameter of the independent pore 72 may be, for example, 2 µm or more and 100 µm or less, 2 µm or more and 50 µm or less, or 50 µm or more and 100 µm or less. The average pore diameter of the independent pore 72 can be determined, for example, by measuring a pore diameter of each of the independent pores 72 exposed to an arbitrary cross section of the abrasive grain layer 3 and calculating an average of these measurement results. In this case, since a portion of the independent pore 72 exposed to an arbitrary cross section of the abrasive grain layer 3 are cut out by the cross section, for example, the pore diameter may be measured by interpolating the shape of the portion cut out from the shape of the remaining portion. Various known methods can be adopted as the interpolation.

[0029] The plurality of pores 7 include a micropore 73. The micropore 73 is a pore 7 having a pore diameter of 2 µm or more and 10 µm or less. Note that the micropore 73 may be a pore 7 having a pore diameter of 2 µm or more and 4 µm or less, or may be pores 7 having a pore diameter of 5 µm or more and 10 µm or less. The pore diameter of the micropore 73 can be, for example, the maximum diameter of the micropore 73. The abrasive grain layer 3 has a plurality of micropores 73. The micropore 73 may be some of the pores 7 constituting the interconnecting pore 71, or may be the independent pore 72.

[0030] A porosity of the micropore 73 in the abrasive grain layer 3 may be, for example, 0.01% or more and 10% or less, 0.01% or more and 5% or less, or 5% or more and 10% or less. The porosity is a percentage of proportion occupied by the micropores 73 in the abrasive grain layer 3. The porosity of the micropore 73 in the abrasive grain layer 3 may be, for example, a percentage of proportion of a total area of the micropores 73 to an area of the abrasive grain layer 3 in an arbitrary cross section of the abrasive grain layer 3.

[0031] As described above, in the metal-bonded grinding stone 1 according to the present embodiment, when the porosity of the plurality of pores 7 in the abrasive grain layer 3 is 40% or more, it is possible to appropriately exhibit the self-sharpening action due to crushing or abrasion of the metal bonding material 5. On the other hand, when the porosity of the plurality of pores 7 in the abrasive grain layer 3 is 99% or less, the strength of the abrasive grain layer 3 can be secured. That is, since the porosity of the plurality of pores 7 in the abrasive grain layer 3 is 40% or more and 99% or less, it is possible to appropriately exhibit the self-sharpening action due to crushing or abrasion of the metal bonding material 5 while ensuring the strength of the abrasive grain layer 3. Therefore, good sharpness can be maintained. When the porosity of the plurality of pores 7 in the abrasive grain layer 3 is 70% or more and 90% or less or 40% or more and 60% or less, these effects are further enhanced.

[0032] In addition, in the metal-bonded grinding stone 1, when each of the plurality of pores 7 is formed in a spherical shape, it is easy to control the strength of the abrasive grain layer 3 and the self-sharpening cycle for exhibiting the self-sharpening action of the abrasive grain layer 3.

[0033] In addition, in the metal-bonded grinding stone 1, when the average of the sphericity of the plurality of pores 7 is 0.2 or more and 1.0 or less, it is easy to control the strength of the abrasive grain layer 3 and the self-sharpening cycle for exhibiting the self-sharpening action of the abrasive grain layer 3. When the average of the sphericity of the plurality of pores 7 is 0.5 or more and 1.0 or less or 0.7 or more and 1.0 or less, these effects are further enhanced.

[0034] In addition, since the metal-bonded grinding stone 1 has the interconnecting pore 71 in which the plurality of pores 7 communicate with each other, the discharging property of the chip is improved, and it is possible to suppress clogging of the pores 7 due to the chip.

[0035] In addition, in the metal-bonded grinding stone 1, when the interconnecting pore 71 includes two or more pores 7 communicating with each other and having a pore diameter of 10 µm or more, it is possible to improve the discharging property of the chip and to secure the strength of the abrasive grain layer 3. On the other hand, when the interconnecting pore 71 includes two or more pores 7 communicating with each other and having a pore diameter of 2,000 µm or less, it is possible to shorten the self-sharpening cycle due to crushing or abrasion around the interconnecting pore 71. That is, when the interconnecting pore 71 includes two or more pores 7 communicating with each other and having a pore diameter of 10 µm or more and 2,000 µm or less, it is possible to secure the strength of the abrasive grain layer 3, to improve the discharging property of the chip, and to shorten the self-sharpening cycle due to crushing or abrasion around the interconnecting pore 71. Therefore, it possible to maintain high sharpness. When the interconnecting pore 71 includes two or more pores 7 communicating with each other and having a pore diameter of 10 µm or more and 1,000 µm or less or 10 µm or more and 100 µm or less, these effects are further enhanced.

[0036] In addition, since the metal-bonded grinding stone 1 has the independent pore 72 not communicating with the other pores 7, it is possible to appropriately exhibit the self-sharpening action due to crushing or the like of the metal bonding material 5 while suppressing a decrease in strength of the abrasive grain layer 3.

[0037] In addition, in the metal-bonded grinding stone 1, since the average pore diameter of the independent pore 72 is 2 µm or more, the strength of the abrasive grain layer 3 can be secured. On the other hand, since the average pore diameter of the independent pore 72 is 100 µm or less, it is possible to shorten the self-sharpening cycle due to crushing or abrasion around the independent pore 72. That is, when the average pore diameter of the independent pore 72 is 2 µm or more and 100 µm or less, it is possible to secure the strength of the abrasive grain layer 3 and to shorten the self-sharpening cycle due to crushing or abrasion around the independent pore 72. Therefore, it possible to maintain high sharpness. When the average pore diameter of the independent pore 72 is 2 µm or more and 50 µm or less or 50 µm or more and 100 µm or less, these effects are further enhanced.

[0038] In addition, in the metal-bonded grinding stone 1, since the plurality of pores 7 include the micropore 73 having a pore diameter of 2 µm or more and 10 µm or less, it is possible to promote fine crushing or abrasion of the metal bonding material 5. Therefore, it is easy to control the self-sharpening cycle for exhibiting the self-sharpening action of the abrasive grain layer 3. When the plurality of pores 7 include the micropore 73 having a pore diameter of 2 µm or more and 4 µm or less or 5 µm or more and 10 µm or less, these effects are further enhanced.

[0039] In addition, in the metal-bonded grinding stone 1, when the porosity of the micropore 73 in the abrasive grain layer 3 is 0.01% or more, it is possible to promote fine crushing or abrasion of the metal bonding material 5. On the other hand, when the porosity of the micropore 73 in the abrasive grain layer 3 is 10% or less, the strength of the abrasive grain layer 3 can be secured. That is, when the porosity of the micropore 73 in the abrasive grain layer 3 is 0.01% or more and 10% or less, it is possible to promote fine crushing or abrasion of the metal bonding material 5 while securing the strength of the abrasive grain layer 3. When the porosity of the micropore 73 in the abrasive grain layer 3 is 0.01% or more and 5% or less or 5% or more and 10% or less, these effects are further enhanced.

[0040] One aspect of the present invention is not limited to the embodiments described above, and can be appropriately changed without departing from the gist of one aspect of the present invention.

[0041] For example, as illustrated in FIG. 3, the metal-bonded grinding stone may include a reinforcing portion 9 provided in the interconnecting pore 71 in order to reinforce an abrasive grain layer 3A. A material of the reinforcing portion 9 is not particularly limited, and the reinforcing portion 9 may contain, for example, a resin such as a phenol resin, an epoxy resin, or a liquid resin, a coating material to which an inorganic material or a metal powder is added, liquid glass, plating, or the like. When the reinforcing portion 9 contains a resin, the reinforcing portion 9 can be easily formed. Since the reinforcing portion 9 for reinforcing the abrasive grain layer 3A is provided in the interconnecting pore 71, the strength of the abrasive grain layer 3A reduced by the interconnecting pore 71 can be improved.

[0042] For example, the reinforcing portion 9 may be filled in at least a part of the interconnecting pore 71 of the abrasive grain layer 3A so as to be connected to at least a part of an inner surface 31 of the abrasive grain layer 3A forming the interconnecting pore 71. Since at least a part of the interconnecting pore 71 is filled with the reinforcing portion 9 so as to be connected to at least a part of the inner surface 31, excessive crushing or abrasion around the interconnecting pore 71 can be suppressed. In the abrasive grain layer 3A of the modification illustrated in FIG. 3, as an example, the reinforcing portion 9 is filled in the entire interconnecting pore 71.

[0043] In addition, in the embodiments described above, although the plurality of pores have been described as including all of the interconnecting pore, the independent pore, and the micropore, the plurality of pores may not include all of the interconnecting pore, the independent pore, and the micropore, and may include only some of the interconnecting pore, the independent pore, and the micropore.

Industrial Applicability

[0044] One aspect of the present invention is applicable to a metal-bonded grinding stone in which a plurality of abrasive grains are dispersed in a metal bonding material.

Reference Signs List

[0045] 

1

Metal-bonded grinding stone

2

Base metal

3

Abrasive grain layer

3A

Abrasive grain layer

5

Metal bonding material

6

Abrasive grain

7

Pore

9

Reinforcing portion

31

Inner surface

71

Interconnecting pore

72

Independent pore

73

Micropore

Claims

1. A metal-bonded grinding stone comprising

an abrasive grain layer in which a plurality of abrasive grains and a plurality of pores are dispersed in a metal bonding material,

wherein a porosity of the plurality of pores in the abrasive grain layer is 40% or more and 99% or less.

2. The metal-bonded grinding stone according to claim 1,
wherein each of the plurality of pores is formed in a spherical shape.

3. The metal-bonded grinding stone according to claim 2,
wherein an average of sphericity of the plurality of pores is 0.2 or more.

4. The metal-bonded grinding stone according to any one of claims 1 to 3,
wherein the plurality of pores include an interconnecting pore formed by communicating two or more of the pores.

5. The metal-bonded grinding stone according to claim 4,
wherein the interconnecting pore includes two or more of the pores communicating with each other and having a pore diameter of 10 µm or more and 2,000 µm or less.

6. The metal-bonded grinding stone according to claim 4 or 5, further comprising
a reinforcing portion provided in the interconnecting pore for reinforcing the abrasive grain layer.

7. The metal-bonded grinding stone according to claim 6,
wherein the reinforcing portion is filled in at least a part of the interconnecting pore so as to be connected to at least a part of an inner surface of the abrasive grain layer forming the interconnecting pore.

8. The metal-bonded grinding stone according to claim 6 or 7,
wherein the reinforcing portion contains a resin.

9. The metal-bonded grinding stone according to any one of claims 1 to 8,
wherein the plurality of pores include an independent pore not communicating with the other pores.

10. The metal-bonded grinding stone according to claim 9,
wherein an average pore diameter of the independent pore is 2 µm or more and 100 µm or less.

11. The metal-bonded grinding stone according to any one of claims 1 to 10,
wherein the plurality of pores include a micropore having a pore diameter of 2 µm or more and 10 µm or less.

12. The metal-bonded grinding stone according to claim 11,
wherein a porosity of the micropore in the abrasive grain layer is 0.01% or more and 10% or less.

Drawing