JP7450134B1 - rotary dresser - Google Patents

Abstract

The rotary dresser includes a base metal 103 having an outer peripheral surface, and an abrasive layer 101 provided on the outer peripheral surface of the base metal 103. The abrasive grain layer 101 has a bonding material 203 provided on the base metal 103 and abrasive grains 204 further fixed by the bonding material 203, and the diameter of the abrasive grain layer 101 of the rotary dresser is the same as that of the abrasive grain layer. It differs depending on the first part and the second part. The area ratio of the active surface 205 on the surface of the abrasive grain layer 101 is smaller as the diameter of the abrasive grain layer 101 increases.

Description

The present disclosure relates to a rotary dresser. This application has priority based on Japanese Patent Application No. 2022-178078, which is a Japanese patent application filed on November 7, 2022, and Japanese Patent Application No. 2023-051173, which is a Japanese patent application filed on March 28, 2023. claim priority under No. All contents described in the Japanese patent application are incorporated herein by reference.

As an example of a rotary dresser that corrects the shape of a general grindstone and the grinding surface, there is a rotary dresser described in Japanese Patent Application Laid-open No. 2012-091292 (Patent Document 1).

JP2012-091292A

A rotary dresser is a rotary dresser that includes a base metal having an outer peripheral surface and an abrasive grain layer provided on the outer peripheral surface of the base metal, the abrasive grain layer being a bonding material provided on the base metal. The diameter of the abrasive grain layer of the rotary dresser differs depending on the part, and the diameter of the abrasive grain layer has a diameter difference of 5% or more depending on the part. The abrasive grains appearing on the surface are provided with a flat working surface, and the area ratio of the working surface on the surface of the abrasive grain layer is smaller as the diameter of the abrasive grain layer increases.

FIG. 1 is a photograph of a rotary dresser 100 according to an embodiment of the present disclosure. FIG. 2 is a diagram showing a state in which the rotary dresser 100 and the grindstone 200 are in contact with each other and the rotary dresser 100 is dressing the grindstone 200. FIG. 3 is a diagram showing a state where the grindstone 200 and the workpiece 300 are in contact and the grindstone 200 grinds the workpiece 300. FIG. 4 is a diagram showing a cross-sectional structure of the abrasive grain layer 101 along the direction from the center to the outer circumference of the rotary dresser 100. FIG. 5 is a schematic diagram of the rotary dresser 100 shown for explaining the method of measuring the area ratio of the working surface. FIG. 6 is a schematic diagram of the rotary dresser 100 shown for explaining a method of measuring the area ratio of the working surface. FIG. 7 is a schematic diagram of the rotary dresser 100 shown for explaining the method of measuring the area ratio of the working surface. FIG. 8 is a schematic diagram of the rotary dresser 100 before dressing produced in the example. FIG. 9 is a schematic diagram of the rotary dresser 100 after dressing 100 times. FIG. 10 is a schematic diagram of the rotary dresser 100 after dressing 100 times and the shape transfer material processing grindstone 400 in contact with the rotary dresser 100. FIG. 11 is a schematic diagram of a shape transfer material processing grindstone 400 and a shape transfer material 500 in contact with the shape transfer material processing grindstone 400. FIG. 12 is a schematic diagram of a shape transfer material 500 to which the shape of the rotary dresser 100 after dressing 100 times is transferred. FIG. 13 is a schematic diagram for explaining a method of measuring the depth of a recess 519 as a wear mark formed on the shape transfer material 500.

[Problems to be solved by this disclosure]
Conventional rotary dressers have had the problem of high dressing resistance.

When dressing a grindstone with a full-form rotary dresser, the diameter of the grindstone becomes smaller in the part where the diameter of the rotary dresser is large, and the diameter of the grindstone becomes larger in the part where the diameter of the rotary dresser is small. In addition, when dressing a grinding wheel for outer diameter grinding where dressing resistance is a problem, the diameter of a rotary dresser is generally smaller than the diameter of the grinding wheel, and the rotation speed during dressing is also higher for a rotary dresser. smaller than Generally speaking, the rotating direction of the rotary dresser and the grinding wheel is opposite to each other (down cut), and if the rotating direction of the rotary dresser and the grinding wheel is the same (up cut), the rotary dresser becomes dull and cannot be used for dressing. It is not used unless there are special reasons such as

When using a full-size rotary dresser in such a situation, the large diameter portion and the small diameter portion of the rotary dresser have different circumferential speed ratios with respect to the grindstone.

That is, the circumferential speed ratio V1 (VRD/V grindstone) between the small diameter part of the rotary dresser and the large diameter part of the grindstone is small, and the circumferential speed ratio V2 (VRD/V grindstone) between the large diameter part of the rotary dresser and the small diameter part of the grindstone is small. It grows and approaches 1.

When the circumferential speed ratio approaches 1, the resistance becomes very large and the cutting ability of the rotary dresser deteriorates.

For this reason, if the composition of the abrasive grain layer of a full-size rotary dresser is the same throughout, the resistance during dressing will differ greatly between the large diameter part and the small diameter part of the rotary dresser, and there will be parts where the dressing resistance is large. As a result, the accuracy of the dressed whetstone tends to deteriorate due to chattering.

Furthermore, the wear of the rotary dresser becomes uneven, and the life of the rotary dresser is shortened.

The rotary dresser of the present disclosure solves the above problems.
FIG. 1 is a photograph of a rotary dresser 100 according to an embodiment of the present disclosure. FIG. 2 is a diagram showing a state in which the rotary dresser 100 and the grindstone 200 are in contact and the rotary dresser 100 is dressing the grindstone 200. FIG. 3 is a diagram showing a state in which the grindstone 200 and the workpiece 300 are in contact and the grindstone 200 grinds the workpiece 300.

As shown in FIGS. 1 to 3, a rotary dresser 100 as a diamond rotary dresser includes a base metal 103 and an abrasive grain layer 101 as a superabrasive grain layer provided on the surface of the base metal 103.

The base metal 103 is made of stainless steel, for example. The base metal 103 has a cylindrical shape, and an abrasive grain layer 101 is provided on the outer peripheral surface of the base metal 103. In the abrasive grain layer 101, diamond as an abrasive grain is fixed. Note that CBN (cubic boron nitride) may be used instead of diamond. Furthermore, diamond and cubic boron nitride may be mixed.

Grooves 102 extending in the circumferential direction are formed in the abrasive grain layer 101 . This groove 102 is formed along the shape of the workpiece. Such a rotary dresser 100 is for dressing a so-called full-form grindstone.

FIG. 4 is a diagram showing a cross-sectional structure of the abrasive grain layer 101 along the direction from the center to the outer circumference of the rotary dresser 100. As shown in FIG. 4, an abrasive grain layer 101 is formed on the surface of the base metal 103 with a low melting point alloy layer 104 interposed therebetween. The abrasive grain layer 101 is manufactured by a reverse plating method, and includes a bonding material 203, which is a plating layer, and abrasive grains 204 fixed to one layer. An abrasive grain layer 101 is fixed on a base metal 103 by a low melting point alloy layer 104 .

The total area ratio of the plurality of action surfaces 205 to the area of the virtual surface 206 that gently connects the action surfaces 205 is expressed as a ratio S.

The working surface 205 of the abrasive grain 204 is formed by grinding or polishing the abrasive grain 204 . By changing the time for grinding or polishing the abrasive grains 204, the area of the working surface 205 can be adjusted. As the abrasive grains 204, it is possible to use not only superabrasive grains such as diamond and CBN, but also conventional abrasive grains such as alumina.

The rotary dresser 100 includes a base metal 103 having an outer peripheral surface 109 and an abrasive grain layer 101 provided on the outer peripheral surface 109 of the base metal 103. The abrasive grain layer 101 has a bonding material 203 provided on the base metal 103 and abrasive grains 204 further fixed by the bonding material 203, and the diameter of the abrasive grain layer 101 of the rotary dresser 100 is the same as that of the abrasive grains. It differs depending on the first region and the second region of the layer 101.

When the diameter of the abrasive layer 101 in the first portion is D1 and the diameter of the abrasive layer 101 in the second portion is D2, (D1-D2)/D1 is 5% or more. The abrasive grains appearing on the surface of the abrasive grain layer 101 are provided with a flat working surface 205 .

The area ratio of the active surface 205 on the surface of the abrasive grain layer 101 is smaller as the diameter of the abrasive grain layer 101 increases.

Preferably, the area ratio (ratio S) of the maximum diameter portion of the working surface 205 in the abrasive grain layer 101 is 5% or more and 15% or less.

Preferably, the larger the diameter of the abrasive grain layer 101 is, the smaller the number of abrasive grains per revolution of the rotary dresser 100 is.

Preferably, the larger the diameter of the abrasive grain layer 101 is, the wider the interval between the abrasive grains 204 is.
The abrasive grains 204 are synthetic diamonds, and the crystal planes of the synthetic diamonds are oriented.

When artificially synthesized diamond is used as the abrasive grains 204, since the crystal plane of the diamond is clearly visible, the diamond is joined with the crystal plane being nearly parallel to the joining surface of the base metal 103. As a result, the abrasive grains 204 are tightly bonded in a stable manner, and even if the amount of grinding required to form a working surface on the abrasive grains 204 is small, the working area ratio can be increased. As a result, the working surface can be easily formed, and the abrasive grain layer 101 becomes thicker, so that the life span is improved.

Preferably, the abrasive grains 204 are arranged linearly on the surface of the abrasive grain layer 101. The direction in which they are arranged may be the axial direction of the rotary dresser 100, the circumferential direction, or a direction at an angle with respect to these directions, and may be in a straight line or a curved shape.

Arranging the abrasive grains 204 linearly makes it easier to adjust the area ratio of the working surface 205 when manufacturing the rotary dresser 100.

5 to 7 are schematic diagrams of the rotary dresser 100 shown for explaining the method of measuring the area ratio of the working surface. In FIGS. 5 to 7, the rotary dresser 100 rotates around the rotating shaft 108. As shown in FIGS. In FIG. 5, the outer circumferential surface 109 has a stepped shape.

Step (1)
Select an arbitrary position on the rotary dresser 100. Assume that a portion with a diameter of D1 is selected.

Step (2)
Select a position that differs in diameter by 5% or more from the position selected in 1) above. Assume that a portion with a diameter D2 is selected. (D1-D2)/D1 shall be 5% or more. Furthermore, assuming that a portion with a diameter D3 is selected, (D2-D3)/D2 is 5% or more.

In the case of a shape in which the diameter changes continuously as shown in FIG. 6, positions are selected that differ by 5%, such as 5%, 10%, and 15%, from the diameter at the position selected in 1) above. Specifically, an arbitrary position (position of line A) is selected. Select the position of line B whose diameter differs by 5% from the position of line A. Select the position of line C whose diameter differs by 5% from the position of line B. Select the position of line D whose diameter differs by 5% from the position of line C.

When the groove 102 is formed as shown in FIG. 7, the position of line A outside the groove 102 is selected. Let the diameter at the position of line A outside the groove be D1, and the diameter at the position of line B inside the groove 102 be D2. If (D1-D2)/D1 is 5% or more, it is also measured on line B.

Step (3)
In the circumferential direction of the position selected in steps (1) and (2) above, ten arbitrary positions are selected in the range of an axial length of 2 mm and a circumferential length of 10 mm. As a result, measurement positions 121 to 124 are determined. There are ten measurement positions 121 on line A. There are ten measurement positions 122 on line B. There are ten measurement positions 123 on line C. There are ten measurement positions 124 on line D.

Step (4)
For each selected position, the area ratio of the working surface of the abrasive grains is measured using a Keyence VR5000 measuring device by following the steps of curved surface correction, cutoff correction, threshold setting, and area measurement.

Specifically, the measuring device was: Keyence VR5000. The measurement principle is the "light sectioning method." The analysis procedure is (1) three-dimensional measurement. (2) Planarize the shape using either or both of A and B below. A: Waviness removal (cutoff processing). Flatten the undulations over a certain wavelength. B: Quadratic curve correction. The arcuate shape obtained by fitting the entire shape with a quadratic curve is flattened. (3) Set the threshold and calculate the area of action. In each of line A, line B, line C, and line D, the average value of the action area measured at 10 points is taken as the action area on that line.

The smaller the circumferential speed difference between the rotary dresser 100 and the grindstone that contacts the rotary dresser 100 (the circumferential speed ratio is closer to 1), the greater the dressing resistance becomes. The circumferential speed difference of the full-form dresser differs depending on the outer diameter of the rotary dresser 100. It is not possible to change the circumferential speed of the general dresser depending on the location. Therefore, in the rotary dresser 100, the proportion of the working surface 205 of the abrasive grains 204 in the portion having a large outer diameter can be reduced to lower the dressing resistance.

The dressing resistance of the entire rotary dresser can be lowered by reducing the dressing resistance of the large-diameter portion of the complete rotary dresser. Furthermore, since the difference in dressing resistance between the large diameter portion and the small diameter portion of the rotary dresser is reduced, the accuracy of the dressed grindstone is improved. Furthermore, the wear of the large diameter portion and the small diameter portion of the abrasive grain layer can be made uniform, and the life of the rotary dresser can be improved.

A working surface is provided at the head of the abrasive grain that acts on the grindstone when the rotary dresser performs dressing, and the area ratio of this working surface greatly influences the dressing resistance. In the general rotary dresser, the larger diameter portion acts on the smaller diameter portion of the grindstone, and the circumferential speed ratio of this portion approaches 1. Therefore, the dressing resistance increases. If the area ratio of the abrasive grain working surface in the large diameter portion of the rotary dresser where this resistance increases is reduced, the dressing resistance in the large diameter portion of the rotary dresser will be reduced, and the dressing resistance of the entire rotary dresser will also be reduced.

(Example)
(Description of rotary dresser 100, grindstone 200 and workpiece 300)
FIG. 8 is a schematic diagram of the rotary dresser 100 before dressing produced in the example. The details are shown in Tables 1 and 2.

The "2 mm width average abrasive grain spacing" is the distance determined by "circumferential length of the center within 2 mm width/number of abrasive grains within 2 mm width" at each location. It should be noted that for abrasive grains located at the outer peripheral edge of a 2 mm wide area and a portion of the abrasive grains falling within this area, the number of abrasive grains is counted as 0.5.

The abrasive grains 204 of the rotary dresser 100 are made of diamond, the base metal 103 (FIG. 3) is made of stainless steel, and the bonding material 203 (FIG. 3) is made of nickel plating. The diameter of the abrasive grains 204 is #20/25 (average grain size 700 μm to 850 μm). The abrasive grains 204 are fixed at intervals in the circumferential direction and arranged linearly.

This rotary dresser 100 dresses a grindstone 200 as shown in FIG.

The grindstone 200 (FIG. 2) to be dressed is a mesh #60 grindstone (average grain size 250 μm) manufactured by Cle Norton Co., Ltd. with a degree of bonding K. The material of the grindstone 200 is WA.

The workpiece 300 (FIG. 3) is a round bar made of S45C and has a diameter of 100 mm and a thickness (length in the rotational axis direction) of 130 mm.

The rotation directions of the rotary dresser 100 and the grindstone 200 are opposite to each other (down dress). This allows the grinding fluid to be sucked between the rotary dresser 100 and the grindstone 200. The rotation directions of the grindstone 200 and the workpiece 300 are also opposite to each other.

The rotary dresser 100 has an average outer diameter of 93 mm, a rotation speed of 1200 rpm, and a circumferential speed of 5.8 m/s. The average outer diameter of the grindstone 200 is 248 mm, the rotation speed is 1490 (rpm), and the circumferential speed is 19.4 m/s. The peripheral speed ratio expressed by the average peripheral speed of the rotary dresser 100/the average peripheral speed of the grindstone 200 is 0.3.

(Explanation of dressing process)
First, the grindstone 200 was dressed using the rotary dresser 100. Next, the grinding process of the workpiece 300 was repeated with this grindstone, and when the accuracy of the workpiece 300 after processing deviated from the specified value, the grindstone 200 was dressed again with the rotary dresser 100. Tables 3 and 4 show the results after repeating this 100 times.

In Tables 3 and 4, "dressing resistance" is the resistance for rotating the rotary dresser whose load in the cutting direction was measured using a piezoelectric sensor "Multicomponent Dynamometer 9257B" manufactured by Kistler.

"Workpiece roughness" is the surface roughness of the workpiece 300 processed by the grindstone 200 immediately after dressing in each of the 100 dressings, and is the average of the 100 measurements measured with a palpable surface roughness meter. value.

"RD radius wear amount when dressing 100 times" is the wear amount of the rotary dresser after dressing 100 times as described above (description of dressing process). FIG. 9 is a schematic diagram of the rotary dresser 100 after dressing 100 times. As shown in FIG. 9, a recess 119 is formed in the outer peripheral surface 109 after 100 dressings. The area in which the recess 119 is formed is the dressing area 118. The reason why the recessed portion 119 is formed is that the portion of the recessed portion 119 mainly comes into contact with the grindstone 200 .

FIG. 10 is a schematic diagram of the rotary dresser 100 after dressing 100 times and the shape transfer material processing grindstone 400 in contact with the rotary dresser 100. As shown in FIG. 10, after the rotary dresser 100 has been dressed 100 times, the rotary dresser 100 is rotated about the rotating shaft 108 and the shape transfer material processing grindstone 400 is rotated about the rotating shaft 408. The shape transfer material processing grindstone 400 is dressed. As a result, the shape of the outer peripheral surface of the abrasive grain layer 101 of the rotary dresser 100 is transferred to the shape transfer material processing grindstone 400. The shape transfer material processing whetstone 400 has a grain size of #60 (average grain size 250 μm) and the type of abrasive grain is WA.The width of the shape transfer material processing whetstone 400 is greater than the width of the rotary dresser 100.

FIG. 11 is a schematic diagram of a shape transfer material processing grindstone 400 and a shape transfer material 500 in contact with the shape transfer material processing grindstone 400. As shown in FIG. 11, the shape transfer material processing grindstone 400 is rotated about the rotation shaft 408, and the shape transfer material 500 is rotated about the rotation shaft 508. Thereby, the round bar-shaped shape transfer material 500 made of material S45C is processed using the shape transfer material processing grindstone 400.

FIG. 12 is a schematic diagram of a shape transfer material 500 to which the shape of the rotary dresser 100 after dressing 100 times is transferred. As shown in FIG. 12, the shape transferred to the shape transfer material 500 is measured in a measurement area 518 using a shape measuring device. Any general shape measuring device may be used for measurement.

FIG. 13 is a schematic diagram for explaining a method of measuring the depth of a recess 519 as a wear mark formed on the shape transfer material 500. In FIG. 13, fine irregularities on the surface observed in the measurement region 518 are shown. When the shape is measured, the reference portion 521, the reference portion 522, and the portion acted upon when the rotary dresser 100 dresses (the bottom of the recess portion 519) all have minute irregularities. The shape measurement device calculates the intermediate point (average position) between the reference portion 521 and the reference portion 522 of the rotary dresser RD transferred to the shape transfer material 500. The midpoint 523 is the midpoint of the reference portion 521. Midpoint 524 is the midpoint of reference portion 522 . Similarly, the shape measuring device calculates the midpoint 526 of the portion that acts when the rotary dresser 100 dresses. The distance L between the straight line 525 connecting the intermediate point 523 of the reference part 521 and the intermediate point 524 of the reference part 522 and the intermediate point 526 of the part that acts when the rotary dresser 100 dresses is "RD radius wear amount after 100 dressings". "become. This distance is a distance in a direction perpendicular to straight line 525.

In the "dress resistance determination" column, if the "dress resistance" was less than 33, it was scored as "A", if it was 33 or more and less than 35, it was scored as "B", and if it was 35 or more, it was marked as "C".

From these results, it can be seen that Samples Nos. 8 and 10, in which the active area ratio is equal at each site, were evaluated as "C" in the dress resistance determination.

It can be seen that sample number 7, which has a small active area ratio in the small diameter portion, was evaluated as "C" in the dressing resistance evaluation.

On the other hand, it can be seen that sample numbers 1 to 6 and 9, in which the effective area ratio in the small diameter portion is large, are evaluated as "A" or "B" in the dress resistance determination. In particular, sample number 9 has an extremely low dressing resistance, so it can be said that it shows excellent results.

In sample numbers 1 to 6 and 9, the larger the diameter of the abrasive layer, the wider the abrasive grain spacing expressed by "2 mm width average abrasive grain spacing." In this case, as shown by sample numbers 1 to 6 and 9, it can be seen that favorable results are obtained.
(Additional note 1)
a base metal having an outer peripheral surface;
A rotary dresser comprising an abrasive grain layer provided on the outer peripheral surface of the base metal,
The abrasive grain layer includes a binding material provided on the base metal and abrasive grains further fixed by the binding material,
The diameter of the abrasive layer of the rotary dresser varies depending on the location,
The diameter of the abrasive grain layer has a diameter difference of 5% or more depending on the part,
The abrasive grains appearing on the surface of the abrasive grain layer are provided with a flat working surface,
In the rotary dresser, the area ratio of the working surface on the surface of the abrasive grain layer is smaller as the diameter of the part of the abrasive grain layer becomes larger.
(Additional note 2)
The rotary dresser according to supplementary note 1, wherein the ratio of the active area of the maximum diameter portion in the abrasive grain layer is 5% or more and 15% or less.
(Additional note 3)
The rotary dresser according to appendix 1 or 2, wherein the larger the diameter of the abrasive grain layer is, the smaller the number of abrasive grains per rotation of the rotary dresser is.
(Additional note 4)
The rotary dresser according to any one of Supplementary Notes 1 to 3, wherein the abrasive grains are spaced wider at a portion where the diameter of the abrasive grain layer is larger.
(Appendix 5)
5. The rotary dresser according to any one of Supplementary Notes 1 to 4, wherein the abrasive grains are artificially synthesized diamonds, and the crystal planes of the artificially synthesized diamonds are oriented.
(Appendix 6)
The rotary dresser according to any one of Supplementary Notes 1 to 5, wherein the abrasive grains are arranged linearly on the surface of the abrasive grain layer.

The embodiments disclosed herein are illustrative in all respects and should not be considered restrictive. The scope of the present invention is indicated by the claims rather than the above description, and it is intended that equivalent meanings and all changes within the scope of the claims are included.

100 rotary dresser, 101 abrasive grain layer, 102 groove, 103 base metal, 104 low melting point alloy, 108,408,508 rotating shaft, 109 outer peripheral surface, 118 dressing region, 203 binding material, 204 superabrasive grain, 205 top surface, 206 virtual surface 300 workpiece, 400 shape transfer material processing grindstone, 500 shape transfer material, 518 measurement area, 521, 522 reference section, 523, 524, 526 intermediate point, 525 straight line. .

Claims (6)

a base metal having an outer peripheral surface;
A rotary dresser comprising an abrasive grain layer provided on the outer peripheral surface of the base metal,
The abrasive grain layer includes a binding material provided on the base metal and abrasive grains further fixed by the binding material,
The diameter of the abrasive layer of the rotary dresser varies depending on the location,
The diameter of the abrasive grain layer has a diameter difference of 5% or more depending on the part,
The abrasive grains appearing on the surface of the abrasive grain layer are provided with a flat working surface,
In the rotary dresser, the area ratio of the working surface on the surface of the abrasive grain layer is smaller as the diameter of the part of the abrasive grain layer becomes larger. The rotary dresser according to claim 1, wherein the area ratio of the working surface of the maximum diameter portion of the abrasive grain layer is 5% or more and 15% or less. The rotary dresser according to claim 1 or 2, wherein the larger the diameter of the abrasive grain layer is, the smaller the number of abrasive grains per rotation of the rotary dresser is. 3. The rotary dresser according to claim 1, wherein the abrasive grains are spaced apart from each other in a region where the diameter of the abrasive grain layer is larger. The rotary dresser according to claim 1 or 2, wherein the abrasive grains are artificially synthesized diamonds, and the crystal planes of the artificially synthesized diamonds are oriented. The rotary dresser according to claim 1 or 2, wherein the abrasive grains are arranged linearly on the surface of the abrasive grain layer.

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