JPS591555B2 - rotary diamond dresser - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary diamond dresser for sharpening and shaping a grinding wheel into a predetermined shape, and an object of the present invention is to improve and stabilize the life of the rotary diamond dresser and increase its economic efficiency. It is something.

A rotary diamond dresser is generally made by implanting a large number of diamonds on the outer peripheral surface, end surface, or both sides of a roll that has been shaped into a desired shape.
While independently rotating and driving at an outer circumferential speed of ~20 m/sec, the same circumferential speed as during grinding (generally 30 to 60 m/sec)
) in the radial direction of the rotating grinding wheel, or
Alternatively, by traversing the grinding wheel in the axial direction with a predetermined depth of cut, the relative circumferential speed between the grinding wheel and the rotary diamond dresser (generally 10~
80m/sec) to shear and crush the abrasive grains of the grinding wheel to sharpen and shape the grinding wheel into a predetermined shape.
In recent years, it has been recognized that the dressing time can be significantly shortened and the wear characteristics of the dresser can be significantly improved compared to single-stone diamond dressers, making it an essential tool mainly in the mass production grinding field. A variety of applications have been developed for this technique.

The diamonds conventionally used in the rotary diamond dressers mentioned above are generally shaped as shown in Figure 1, and their sizes range from 40 to 250 stones (1/4
0 force rat to 1/250 force rat), and is implanted so that its flat parts 2, 3, 4 are exposed on the outer circumferential surface or end face of the roll on which dressing work is performed.

One of the biggest problems with such a rotary diamond dresser is that the rotary diamond dresser is applied especially to the field of precision mass production grinding, and in that case, due to the dressing mechanism, among the many diamonds implanted in the rotary diamond dresser, the rotation of the dresser is difficult. When most of the dressing load is concentrated only on the diamond group implanted in a limited annular band centered on the axis, as the dressing operation is repeated, the tip surface portion 2 of the limited diamond group
, 3 and 4, wear and variations in wear rate cause harmful chatter on the grinding surface and deterioration of the roughness of the grinding surface. Not only does this deteriorate the properties of the diamonds, but also the differences between the individual rotary diamond dressers due to variations in the orientation and size of the diamond crystal planes exposed on the surface of the rotary dresser of the individual diamonds included in the limited diamond group mentioned above. The durability itself varies considerably, making it extremely difficult to set appropriate and economical management standards (determining replacement timing) for rotary diamond dressers.

Increasing the distribution density of diamond has traditionally been thought of as a countermeasure to the above, but if the distribution density is increased more than necessary, the surface of the abrasive grains on the whetstone will be shaped too smoothly during dressing, resulting in insufficient sharpening action. In addition to deteriorating the grinding ability (cutting ability) of the whetstone and making it easier to cause harmful "burn" on the workpiece to be ground, it also significantly lengthens the production time and increases production costs. Currently, this method is not considered the preferred method.

Now, the hardness and wear resistance of diamond vary greatly depending on the direction of its crystal planes, and the eight equilateral triangular faces 6 of the octahedral diamond shown in Figure 2, that is, the octahedral faces, are indicated by the so-called crystal face index. It is called the 1,1,1 plane, and is considered to be the hardest and most wear-resistant plane among the diamond crystal planes.

(Special case, 1) This means that the method of polishing decorative diamonds in the direction of the plane shown in Figure 3 31 has been practiced since ancient times.
The method of polishing in the direction of the surface shown in Figure 4 and 41 (Rosenzukat method) has been adopted, but polishing in the direction parallel to the octahedral surface is rarely adopted. it is obvious. In rare cases, when the octahedral surface of an octahedral diamond is rubbed with diamond powder as the table surface of a diamond cutting tool, one of the directions A, b, and c in Figure 2 is selected, and the direction along the ridge line 7 is almost always selected. It is considered unlappable. That is, among the octahedral faces 6, which are the hardest among the diamond crystal faces, the direction parallel to the ridge line 7 has been considered to be the hardest direction. (Characteristic 2) The present invention applies the characteristics of the octahedral diamond described above to a rotary diamond dresser to significantly improve its durability.

In other words, the main part of the dressing work load is concentrated in the rotary diamond dresser, and the plurality of octahedral diamonds are placed on one of the eight sides in a limited annular band centered on the rotation axis. Either the body surface 6 is exposed substantially parallel to the rotational direction of the contact surface of the octahedral diamond of the mold grinding wheel, or at the same time, any one of the three ridgelines bounding the octahedral surface is The main feature is that the contact surface of the grinding wheel with the octahedral diamond is exposed substantially parallel to the direction of the relative rotational speed vector of the 1fC square.

Below, several application examples will be explained in detail in comparison with conventional methods.

FIG. 5 shows an example of a general traverse-type rotary diamond dressing device using a cup-shaped rotary diamond dresser 40, in which 10 indicates a simple surface of a workpiece, such as the outer circumferential surface of a cam shaft (not shown). This is a grinding wheel that is rotated at high speed around a rotational axis 11 in order to grind a linear outer peripheral surface, and the outer peripheral grinding surface of the grinding wheel 10 is shown as simply consisting of a direct portion 12 only. A dressing device 20 that corrects and sharpens the grinding wheel 10
A carriage 22 is slidably mounted on the base 21 of the grinding wheel 10 in parallel with the axis 11 of the grinding wheel 10, and the carriage 22 is connected to a piston 24 that fits into a cylinder 23 fixed to the base 21 and is connected to the cylinder 23. Switching valve 25
It slides on the base 21 by switching. Carriage 2
2, a subcarriage 26 is slidably fitted at right angles to the axis 11 of the grinding wheel 10, and the subcarriage 26 is fed to cut in the axial direction of the grinding wheel 10 by an appropriate cutting device 27. A sub-base 28 is fixed on this sub-carriage 26, and a spindle head 29 is further fixed on this sub-base.
is fixed. A bevel-shaped rotary diamond dresser 4 is attached to the tip of the spindle head 29 facing the grinding wheel 10.
The grinding wheel 10 is rotatably supported substantially at right angles to the axis 11 of the grinding wheel 10, and is driven one rotation by the motor 34 during repair work. In addition, the angle between the axis of the cutter-shaped rotary diamond dresser and the axis of the grinding wheel 10 is determined by the four arc-shaped elongated holes 35 cut on the sub-base 32.
After turning the sub-base 32 at an arbitrary small angle along
By fixing it on the subcarriage 26 with a bolt 36, it is also possible to adjust the angle within 32 degrees around the 90 bar. Therefore, by switching the switching valve 25, the cylinder 23 is actuated and the carriage 22 is moved parallel to the axis of the grinding wheel 10, thereby giving an appropriate cutting feed in the axial direction of the grinding wheel 10 by the cutting device 27. The cup-shaped rotary diamond dresser is moved parallel to the linear generatrix of the grinding wheel 10.
The grinding surface 12 of is corrected. One of the features of such a traverse-type rotary diamond dresser is that the width of the annular band portion of the dresser 40 in which diamonds are implanted can be made narrower than the width of the grinding wheel. The number of units used can be reduced. However, in this case, the contact mode between the cup-shaped rotary diamond and the grinding wheel is such that the outermost diamond on the end face 43 of the cup-shaped rotary diamond dresser 40 is the most Since traverse dressing is performed while being in strong contact with the grinding wheel 10, the dressing work load is not divided almost equally among all the diamonds as in the case of a flange type rotary diamond dresser, but the A limited number of diamonds 5 are implanted in one row on the outermost periphery of the end face 43 of the conventional rotary diamond dresser 40 shown in FIGS. 7 to 10.
It is unavoidable that the dressing work load is intensively imposed on 1 and 51. However, the cutlet-shaped rotary diamond dresser that has been used in the past is shown in Figures 7 to 10.
As shown in detail in the figure, several rows of diamonds having a general shape as shown in FIG. In the portion 53, 100 to 200 diamonds 52 in size (1/100 to 1
/200 carat) slightly larger diamond 5
1 or 40 to 100 diamonds (1/40 to 1/100 carat) have been selected and arranged and planted at a pitch of 2 to 3 m 1 L. Diamond 51, 51,...
・Due to the wear of these diamonds 51, 51 and the variation in the degree of wear due to the severe dressing workload concentrated on the grinding surface, the roughness of the ground surface deteriorates and harmful chatter marks are induced on the grinding surface, resulting in the wear and tear of the diamonds 51 and 51. It reaches the end of its lifespan when it needs to be replaced, reducing its economic efficiency. In addition, the diamond shown in FIG. 1 is important because the direction and size of the crystal plane of the diamond flat portion (51 in FIG. 10) exposed at the end face portion 43 varies considerably. As this is unavoidable, large variations in the wear depth of the individual diamonds 51, 51 occur, forming uneven surfaces on each other, which deteriorates the roughness of the ground surface and induces harmful chatter marks on the ground surface. Since the timing of replacing the cup-shaped rotary diamond dresser, that is, the life span of the cup-shaped rotary diamond dresser itself, varies greatly, it has caused considerable problems in determining the appropriate and rational replacement timing for the cup-shaped rotary diamond dresser, and in turn, in quality control. The current situation is that The turn-shaped rotary diamond dresser, which is an embodiment of the present invention, is used for dressing work inside the end face 43 of the dresser 40 for the purpose of extending and stabilizing the life of the dresser, which is relatively short and has large variations among the dressers. An octahedral diamond 5 shown in FIG. It is planted so as to be exposed (Fig. 14) almost parallel to the rotational direction of the contact surface with the grinding wheel 10 shown in the figure, that is, in the case of the relative relationship shown in Fig. 6, almost parallel to the end surface 43 of the dresser. Or, at the same time, any one of the three ridgelines 7 bounding the octahedral surface 6 is the relative rotational speed vector VR (11th figure)
It is characterized by being planted so that it is exposed almost parallel to the direction of (Fig. 15).

Strictly speaking, when synthesizing the relative rotational speed vector VR of the grinding wheel with respect to the dresser with the relative rotational speed vector diagram in Figure 11, the relative traverse speed vector FR of the grinding wheel with respect to the dresser in the direction of the grindstone axis should also be considered. However, FR is omitted because it is usually around 0.5% of VR, which is so small that it can be ignored. An example of the embodiment will be explained below mainly with reference to FIG. 16. First, the outer diameter of the desired cup-shaped rotary diamond dresser, φd (FIG. 12)
The inner circumferential surface 54 has an inner diameter φd1 larger by the amount of shrinkage during sintering.
A female die 56 having an inner end surface 55 having a width e1 approximately equal to the width e of the end surface of the dresser in which the diamond is to be implanted (FIG. 12) is manufactured, and an adhesive is applied to the inner end surface 55 of the female mold 56. A large number of octahedral diamonds 40 are placed on the outermost portion of the peripheral end surface portion 55 with one octahedral surface 6 in close contact with the inner peripheral end surface portion 55 of the female die, or the inner peripheral end surface portion 55 is
Any one of the three ridge lines 7 that is in close contact with the octahedral surface 6 and that borders the octahedral surface 6 is the 15th ridge line with respect to the axial direction of the female mold.
It is glued so that it forms an angle approximately equal to the θ2 line in the figure and in the direction of FIG. 15 when viewed from the back side.

Next, a large number of diamonds 52 having the shape shown in FIG.
Glue. A trigram octahedral diamond 5 is 1/40
2 to 4 pieces of carat to 1/120 carat size
The product of the rotation speed NR per minute of the cup-shaped rotary diamond dresser 40 and the total number Nd on the circumference of one end face of the octahedral diamond 5, n-NRXnd, is the grinding wheel 10 with a circumferential pitch of mm. rotations per minute N
The remaining diamonds 52 are 1/100 carat to 1/200 carat in size and are glued together in the axial direction at a rate of 40 to 60 pieces/d. It is glued to an annular band centered on the axis 44 with a width of 2 mm.

Also, this annular band portion and the annular band portion 53 to which the octahedral diamond 5 is bonded are not completely separate but partially overlap. It is preferable to let Furthermore, a mandrel 57 is arranged concentrically with the female mold 56, and the space between the female mold 56 and the mandrel 57 is filled with fine powder such as tungsten or tungsten carbide, so that fine powder such as tungsten or tungsten carbide is placed between the fine powder and between the fine powder and the diamond. For example, molten nickel silver is injected into the microspace of diamonds 40, 52,
A fine powder such as tungsten and a core metal 57 are integrated, and after cooling, the female die 50 is removed and a cup-shaped rotary diamond 40 is formed.
After machining and finishing the outer periphery 59, holes 60 (FIG. 12), etc., the exposed portions of the diamonds 5 and 52 to the end surface 43 of the dresser 40 are wrapped to complete the final product. 17th
The figure shows an example of a general orthogonal traverse type rotary diamond dressing device that uses a straight type rotary diamond dresser, and reference numeral 80 indicates a rotation axis 81 for grinding a journal part or a pin part of a crankshaft (not shown). The grinding wheel rotates at high speed as the center, and the grinding surface on the outer periphery of the grinding wheel 80 has a straight part 72 and circular arc parts 73 at both ends.
073. Base 7 of dressing device 71 for modifying such grinding wheel 80
A carriage 75 is slidably mounted on the base 74 in parallel with the axis 81 of the grinding wheel 80.
It slides on the base 74 by switching a switching valve 78 connected to the cylinder 76 and connected to a piston J and V fitted in a cylinder 76 fixed to the cylinder 76 . A slider 79 is slidably fitted into the carriage 75 at right angles to the axis of the grinding wheel 80, and the pressure of the cylinder 83 acting on the piston 82 integrated with the slider 79 is applied to the slider 79 against the template 84 fixed to the carriage 75. stylus 85
Ensure contact pressure. A ram 86 fitted into the slider 79 so as to be slidable at right angles to the axis of the grinding wheel 80 is fed by cutting in the axial direction of the grinding wheel 80 by an appropriate cutting device 87. A straight rotary diamond dresser 70 is attached to the tip of the ram 86 facing the grinding wheel 80 so as to be rotatably perpendicular to the axis of the grinding wheel 80, and is driven one rotation by a motor (not shown) during dressing work. It's getting old. Therefore, by switching the switching valve 78, the cylinder 76 is actuated, the carriage 75 is moved parallel to the axis 81 of the grinding wheel 80, and the shape of the template 84 is adjusted with the stylus 85 in contact with the template 84 due to the pressure of the cylinder 83. The dresser 70 is moved parallel to the generatrix of the grinding wheel 80 to dress the grinding surface of the grinding wheel 80. The characteristics of such a traverse type rotary diamond dresser compared to a flange type rotary dresser are that the width of the dresser 70 can be made narrower than the width of the grinding wheel, thereby reducing the number of diamonds used, and even if the shape of the grinding wheel changes slightly, the template remains unchanged. There is no need to buy a new expensive rotary diamond dresser by simply changing the shape of the 84, and the present invention is highly flexible.

However, in this case, the manner of contact between the straight diamond dresser 70 and the grinding wheel 80 is limited to a limited annular band (a ring band) closest to the end surface on the outer peripheral surface of the dresser 70, as shown in FIGS. 17 and 18. 91 in Figures 19-21)
In order to carry out the traverse dressing work with the diamond in contact with the grinding wheel 10 most strongly, the first
Diamonds 51 are exposed and implanted in a limited annular band 91 near the end face in the outer peripheral surface 94 of the conventional traverse type rotary diamond dresser 70 shown in FIGS. 9 to 21.
The dressing workload is intensively imposed on 51. However, the conventionally used traverse type rotary diamond dresser, as shown in detail in Figs. 19 to 21, has a coating on its outer peripheral surface with a density of 30 to 60 diamonds/ml as shown in Fig. 1. Diamonds of a general shape are exposed and implanted, and an annular band portion 91ifC centered on the axis 95 where the dressing work load is most severely concentrated is 1/1 the size of the diamonds 52 in the other portion 92.
Diamonds that are the same or slightly larger than 0.00 to 1/200 carat, i.e. 1/70 to 1/180 carat5
1 are arranged and implanted at a pitch of about 2 to 3 mm, but at this level, the diamonds 51,
As a result, these diamonds 51,5
Due to the abnormal wear rate (1) and the variation in the degree of wear, the roughness of the ground surface (3) deteriorates at a very early stage, leading to the end of the life of the dresser and reducing its economical efficiency.

Not only this, but since the diamond shown in Figure 1 is used, the direction and size of the crystal plane of the diamond flat part (51 in Figure 21) exposed on the critical end outer peripheral surface 91 varies considerably. Since this is practically unavoidable, variations in the wear rate of the individual diamonds 51, 51 will eventually greatly change the life of the dresser itself (time to replace the dresser). The current situation is that it is difficult to determine an appropriate and rational replacement period for the expensive rotary diamond dresser, and also to control quality. The traverse type rotary diamond dresser included in the present invention is designed to extend and stabilize the life of the dresser, which is relatively short and has large variations between dressers. The octahedral diamond 5 shown in FIG.
Rotation direction V on the contact surface with the grinding wheel 80 shown in Figure 8
In the case of the relative relationship shown in FIG. 18, it is exposed and planted as shown in FIG. The relative rotational speed vector V where the ridge line 7 is the contact surface of the octahedral shape of the grinding wheel 80 with respect to the diamond.
R (Figure 22) so that it is exposed almost parallel to the direction (second
Figure 5) Planted. FIG. 26 shows a width-determining rotary diamond dresser for dressing the grinding surface of a grinding wheel 110 to a predetermined width for highly accurate grinding of slit grooves, etc. of a rotor for a hydraulic pump to a predetermined width. This shows one example.

That is, a pair of width-determining rotary diamond dressers 100 are attached to the end face portions 9 of both dressers 100100 on which a large number of diamonds are exposed and implanted by spacers 101.
Adjust the facing gap tl between 8 and 98 to be equal to the tip grindstone width t1 of the grinding wheel 110 to be shaped,
The rotation peripheral speed V of the dresser end surface portion 98 is controlled by a motor (not shown above) fixed to the shaft 102 of the dressing device.
(m/Sec), a motor (not shown) applies a rotation peripheral speed V (m/Sec) to the dresser outer peripheral end surface 98.
Sec), the grinding wheel 110 is rotated at a feed rate f that is much smaller than the circumferential speeds V and V by an unillustrated cutting device in a direction perpendicular to the rotation axis 111 of the grinding wheel 110. By feeding the grinding wheel 110, the grinding surface of the grinding wheel 110 is dressed to a predetermined width tl.

In the width-determining rotary diamond dresser 100 shown in FIG. 26, it is clear that the most severe dressing work is concentrated on the limited width centered around the rotational axis 103 at the outermost end surface of the dresser 100. annular band 98 of
Problems similar to those of the cup-shaped rotary diamond dresser and the traverse-type rotary diamond dresser described above currently exist in diamond groups exposed and implanted. A rotary diamond dresser for width determination, which is an embodiment of the present invention, has an annular band 98R on the outermost peripheral end surface centered on the rotation axis 103, where the burden of dressing work is concentrated, for the purpose of extending the life of the dresser and improving stability. (Second
8), a plurality of the octahedral diamonds 5 are cut into a grinding wheel 110 with one octahedral surface 6 shown in FIGS. 26 and 27.
It is exposed and implanted almost parallel to the rotational direction V on the contact surface.

(Figs. 29 and 30) Diamonds on the outer circumferential surface 97R of the dresser (Fig. 28) that come into contact with the outer circumferential surfaces 112, 112 (Fig. 26) of grinding wheels of low importance that are not involved in width determining grinding, Since concentrated loads cannot be applied and the diamonds 52 are not generally used as a key sign to determine the life of the dresser, diamonds 52 in the shape shown in Fig. 1, which are conventionally used, are planted so as to be distributed and exposed at a distribution density of 30 to 60 diamonds/Cd. There is. In addition, as shown in FIG.
Like the 98R, 8L also has an octahedral diamond,
Also, the outer peripheral surface 97L has diamonds 52 like 97R.
When the 98R side reaches the end of its lifespan, it is exposed and planted.
As described above, the present invention is designed so that the opposite 98L side can be used, and diamonds may be exposed and implanted only on the 98R and 97R sides. A plurality of octahedral diamonds are placed in an annular band centered on the rotational axis of the rotary diamond dresser, which mainly determines the life of the dresser. Any one of the three ridge lines exposed substantially parallel to the rotational direction of the contact surface or simultaneously bounding the octahedral surface is on the contact surface of the grinding wheel with respect to the octahedral diamond. Since it is planted so that it is exposed almost parallel to the direction of the relative rotational speed vector of the diamond, it corresponds to the grinding surface of the grinding wheel while ensuring reproducibility of the most stable crystal surface with the highest abrasion resistance of diamond. Therefore, the life of the rotary diamond dresser is significantly extended and stabilized compared to the conventional one.

Although the unit price per carat of the octahedral diamond is higher than that of conventionally commonly used diamonds as shown in Figure 1, the effect of extending the life of the dresser is significant and compared to the conventional method. If the effect of making it easier to determine the optimal time to replace the dresser and further improving the quality control of ground products is comprehensively evaluated, the economic efficiency itself can be significantly improved.

Furthermore, considering that the average wear resistance of individual diamonds is significantly superior to that of conventional diamonds, the total number of diamonds used can be reduced without deteriorating the durability life compared to conventional dressers, and the manufacturing time of dressers can be reduced. It is also possible to improve the grinding ability (mainly sharpness) of the shortened and dressed grindstone.

[Brief explanation of drawings]

FIG. 1 is a plan view of several examples of diamonds commonly used in rotary diamond dressers, FIG. 2 is a perspective view of an octahedral diamond mainly used in the rotary diamond dresser of the present invention, and FIG. The figure is a perspective view of a diamond showing the softest surface 31 of an octahedral diamond, Figure 4 is a perspective view of a diamond showing the crystal plane direction 41, which can also be polished, of an octahedral diamond, and Figure 5 is a cup-shaped rotary diamond. A plan view of a general traverse-type rotary diamond dressing device that employs a dresser, Fig. 6 is a vertical cross-sectional view showing the relative positional relationship of contact between the cut-shaped rotary diamond dresser and the grinding wheel, and Fig. 7 is a general A vertical cross-sectional view of a cup-shaped rotary diamond dresser, Fig. 8 is a front view of Fig. 7, and Fig. 9
The figure is an enlarged view of part B in Fig. 7, Fig. 10 is an enlarged view of part C in Fig. 8, and Fig. 11 is a grinding wheel located near the contact surface between the rotary diamond dresser and the grinding wheel in Fig. 6. Relative rotational speed vector diagram in arrow A direction with respect to the dresser, 1st
2 is a longitudinal sectional view of the cup-shaped rotary diamond dresser of the present invention, FIG. 13 is a front view of FIG. 12, FIG. 14 is an enlarged view of section D in FIG. 12, and FIG. 15 is an enlarged view of section E in FIG. Fig. 16 is a vertical cross-sectional view of the assembly of a female die for gluing and sintering diamond for the cup-shaped rotary diamond dresser of the present invention, and Fig. 17 is a general orthogonal traverse-type rotary diamond. Top view of dressing device,
FIG. 18 is a longitudinal sectional view showing the relative positional relationship of contact between the orthogonal traverse type rotary diamond dresser and the grinding wheel;
Fig. 19 is a vertical sectional view of a general orthogonal traverse type rotary diamond dresser, Fig. 20 is an enlarged view of section F in Fig. 19, Fig. 21 is a plan view taken in the direction of arrow G in Fig. 20, and Fig. 22 is FIG. 18 is a vector diagram of the relative rotational speed of the grinding wheel in the vicinity of the contact surface between the dresser and the grinding wheel in the direction of arrow H relative to the dresser, and FIG. 23 is a longitudinal sectional view of the orthogonal traverse type rotary diamond dresser of the present invention. Figure 24 is an enlarged view of the J part in Figure 23, Figure 25 is a plan view of the K arrow in Figure 24, and the second
Figure 6 is a horizontal cross-sectional view of a grinding wheel and rotary diamond dresser used in general dressing for width determination, and Figure 27 is a horizontal cross-sectional view of the grinding wheel and rotary diamond dresser for width determination in Figure 26 near the outermost peripheral end surface. Fig. 28 is a cross-sectional view of the rotary diamond dresser for width determination of the present invention, and Fig. 29 is an enlarged view of Fig. 28 in the direction of S arrow. 30 is an enlarged view of FIG. 28 in the direction of arrow N. 5... Octahedral shaped diamond, 6... Octahedral surface,
7...Ridge line, 10,80,110...Grinding wheel, 5
2...General diamond, 53, 91, 98...
-Relative rotational speed vector of the annular band, VR...grinding wheel.

Claims (1)

[Scope of Claims] 1. A plurality of octahedral diamonds are placed in the current band centered on the axis of rotation, with one octahedron being approximately parallel to the direction of rotation at the contact surface with the octahedral diamond of the grinding wheel. A rotary diamond dresser that is planted so that it is exposed. 2. In the rotary diamond dresser according to claim 1, any one of the three ridgelines bounding the octahedral surface has a relative rotational speed at the contact surface of the grinding wheel with respect to the octahedral diamond. A rotary diamond dresser that is installed so that it is exposed almost parallel to the direction of the vector.