WO2012046614A1

WO2012046614A1 - Dressing device

Info

Publication number: WO2012046614A1
Application number: PCT/JP2011/072341
Authority: WO
Inventors: 信彦辻
Original assignee: Ntn株式会社
Priority date: 2010-10-08
Filing date: 2011-09-29
Publication date: 2012-04-12
Also published as: DE112011103390T5; JP5586409B2; JP2012081542A; CN103153541A; CN103153541B

Abstract

Provided is a dressing device wherein the operation time required to change the position of a diamond dresser with respect to the center of a pivot is short, and a positioning error of the diamond dresser does not tend to occur. A configuration, which comprises a pivot (5) that is supported to be rotatable, a pivot motor (8) that rotationally drives the pivot (5), a turning radius change shaft (12) that is supported to be rotatable about a position eccentric with respect to the center of the pivot (5) in the pivot (5), and a turning radius change shaft motor (14) that rotationally drives the turning radius change shaft (12), the turning radium change shaft (12) being provided with a dresser holder (16) to which a diamond dresser (15) is detachably attached, is adopted for a dressing device (1).

Description

Dressing equipment

This invention relates to a dressing device used for forming a grindstone.

Generally, the raceway surfaces of the inner and outer rings of the ball bearing are formed by grinding using a grindstone having an arcuate cross section. This grinding wheel is formed into a circular arc shape by scraping the surface of the grinding wheel with a diamond dresser in which diamond is fixed to the tip of the shank. In addition, when the surface of the grindstone is cut with a diamond dresser, a dressing device that rotates the diamond dresser so as to draw an arcuate locus is used.

As such a dressing device, those shown in FIGS. 15 and 16 are known. The dressing device 30 has a turning shaft 31 that is rotatably supported and a turning shaft motor 32 that rotationally drives the turning shaft 31. The turning shaft 31 is a diamond in which a diamond is fixed to the tip of a shank. A dresser holder 34 to which the dresser 33 is detachably attached is provided.

In forming the grindstone G using this dressing apparatus 30, the grindstone G before molding is rotated at a fixed position, and the diamond dresser 33 is brought into contact with the surface of the grindstone G. In this state, as shown in FIG. Next, the dresser holder 34 holding the diamond dresser 33 is turned together with the turning shaft 31. As a result, the tip of the diamond dresser 33 moves so as to draw an arc-shaped trajectory, the surface of the grindstone G is scraped along the trajectory, and the grindstone G is formed into an arc-shaped cross section.

Here, when the radius of the cross-section arc of the grindstone G is changed, it is necessary to change the turning radius of the tip of the diamond dresser 33. For this purpose, the position of the diamond dresser 33 relative to the center of the turning shaft 31 of the dressing device 30 is changed. There is a need to.

Conventionally, the operation of changing the position of the diamond dresser 33 is performed by diamond positioning corresponding to the distances R ₁ and R ₂ from the center of the turning shaft 31 to the tip of the diamond dresser 33 as shown in FIGS. Jigs J1 and J2 are prepared, and if necessary, one of the diamond positioning jigs J1 and J2 is brought into contact with the reference surface 34a of the dresser holder 34, and the tip of the diamond dresser 33 is placed on the diamond positioning jigs J1 and J2. The diamond dresser 33 is moved to a position where it hits, and the position of the diamond dresser 33 is fixed at that position.

However, the operation of changing the position of the diamond dresser 33 requires a long operation time and is likely to cause a positioning error because highly accurate positioning is performed manually.

Even after the position of the diamond dresser 33 is changed once, if the tip of the diamond dresser 33 is worn, the turning radius of the tip of the diamond dresser 33 gradually increases. As a result, an error occurs in the radius of the cross-section arc of the grindstone G. It can happen. Therefore, when the wear of the tip of the diamond dresser 33 progresses, in order to correct the error due to wear, the radius of the cross-section arc of the formed grinding wheel G is measured, and the operator determines the difference between the measured radius and the target radius. The position of the diamond dresser 33 is adjusted again based on the calculated difference. However, there is a problem that the dressing device 30 needs to be stopped once when performing this adjustment.

The problem to be solved by the present invention is to provide a dressing device in which the work time for changing the position of the diamond dresser with respect to the center of the pivot axis is short, and the positioning error of the diamond dresser is unlikely to occur.

In order to solve the above-mentioned problem, a pivot shaft supported rotatably, a pivot shaft motor that rotationally drives the pivot shaft, and a position eccentric to the center of the pivot shaft inside the pivot shaft. A turning radius changing shaft that is rotatably supported and a turning radius changing shaft motor that rotationally drives the turning radius changing shaft, and a dresser holder to which a diamond dresser is detachably attached to the turning radius changing shaft is provided. Was adopted for the dressing device.

In this case, the position of the diamond dresser can be changed by rotating the turning radius changing shaft with the turning radius changing shaft motor and controlling the rotation angle. That is, the operation of changing the position of the diamond dresser with respect to the center of the turning axis can be performed by numerical control of the turning radius changing shaft motor, not by manual work. Therefore, the work time for changing the position of the diamond dresser is shortened, and a positioning error of the diamond dresser is hardly generated.

This dressing device is preferably provided with a dresser tip detection sensor at a position where the tip of the diamond dresser passes when the turning radius changing shaft is rotated. In this way, based on the rotation angle of the turning radius changing shaft motor when the dresser tip detection sensor detects the tip of the diamond dresser, it is possible to correct the turning angle of the turning radius changing shaft at the time of grinding wheel formation. Become.

The operation of correcting the rotation angle of the turning radius changing shaft can be performed by an operator reading the rotation angle of the turning radius changing shaft, but when the dresser tip detection sensor detects the tip of the diamond dresser, If a control device for correcting the rotation angle of the turning radius changing shaft at the time of grinding wheel formation is provided based on the rotation angle of the turning radius changing shaft motor, the above correction work can be automated and performed without stopping the dressing device. It becomes possible.

If the control device is configured to perform synchronous control that changes the rotation angle of the turning radius changing shaft in accordance with the rotation angle of the turning shaft at the time of forming the grindstone, a grindstone having a free cross-sectional shape other than an arc can be accurately obtained. Molding becomes possible.

As the turning radius changing shaft motor, a servo motor, a stepping motor, a motor with a rotary encoder, or the like can be employed. The servo motor is a motor that incorporates a sensor that detects the rotation angle of the motor and performs feedback control based on the difference between the rotation angle of the motor detected by the sensor and the target angle. A stepping motor is a motor that rotates by an angle proportional to the number of input pulses.

A grindstone shaft that holds the grindstone can be provided so as to be movable in the axial direction, and a driving device that drives the grindstone shaft in the axial direction can be provided. In this way, when the surface of the grindstone is shaved with the diamond dresser, the grindstone having a linear cross section can be formed with high accuracy by driving the grindstone shaft in the axial direction.

It is possible to provide a speed reducer that decelerates the rotation of the turning radius changing shaft motor and transmits it to the turning radius changing shaft. In this way, the rotation angle error of the turning radius change shaft with respect to the rotation angle error of the turning radius change shaft motor is reduced, so that the rotation angle of the turning radius change shaft can be positioned with high accuracy.

It is possible to provide a clamp mechanism capable of switching between a clamped state that prevents rotation of the turning radius changing shaft and a free state that allows rotation of the turning radius changing shaft. If it does in this way, after positioning the rotation angle of a turning radius change axis, it will become possible to improve support rigidity of a diamond dresser by preventing rotation of a turning radius change axis with a clamp mechanism.

The dresser holder may be a diamond dresser with a diamond fixed to the tip of the shank, or a rotary diamond dresser with a diamond fixed to the outer periphery of the wheel.

According to the dressing apparatus of the present invention, the operation of changing the position of the diamond dresser with respect to the center of the turning axis can be performed by numerical control of the turning radius changing shaft motor instead of the manual work, so the position of the diamond dresser is changed. The working time is short, and a diamond dresser positioning error hardly occurs.

The front view which shows the dressing apparatus of embodiment of this invention Fig. 1 is an enlarged cross-sectional view of the vicinity of the pivot axis Sectional view along line III-III in FIG. The figure which shows the turning radius of the front-end | tip of the diamond dresser shown in FIG. It shows a state in which the turning radius of the tip of the diamond dresser is changed from R ₁ to R ₂ shown in FIG. 4 The figure which shows the state which rotated the dresser holder shown in FIG. 5, and detected the front-end | tip of the diamond dresser with the dresser front-end | tip detection sensor. The figure which shows operation | movement of a dresser holder when the synchronous control which changes the rotation angle of a turning radius change axis | shaft according to the rotation angle of the turning axis shown in FIG. When turning the turning radius changing shaft so that the diamond dresser shown in FIG. 3 overlaps the center line of the turning shaft, and turning the turning shaft in this state to form a grindstone having a concave cross-sectional shape Of the operation of the dresser holder By rotating the turning shaft without moving the grinding wheel shaft shown in FIG. 3 in the axial direction, and then stopping the turning shaft and moving the grinding wheel shaft in the axial direction, a grinding stone having a cross section combining an arc and a straight line is obtained. Diagram showing the operation of the dresser holder when molding By rotating the swivel shaft without moving the grindstone shaft shown in FIG. 3 in the axial direction and performing a combined operation combining the rotation of the swivel shaft and the axial movement of the grindstone shaft in the middle, an arc and a non-arc The figure which shows operation | movement of a dresser holder when shape | molding the grindstone with the cross-sectional shape which combined the curve. The figure which shows the Example which employ | adopted the type of dresser holder which attaches the rotary diamond dresser which fixed the diamond to the outer periphery of a wheel The figure which shows the Example which uses the motor with a rotary encoder as a motor for turning radius change axes The figure which shows the Example incorporating the reduction gear which decelerates rotation of the motor for turning radius change shafts, and transmits to a turning radius change shaft The figure which shows the Example which incorporated the clamp mechanism between the inner periphery of an eccentric hole, and the outer periphery of a turning radius change shaft. Front view showing a conventional dressing device Sectional view along line XVI-XVI in FIG. Using diamond positioning jig J1, shows the work of adjusting the distance to the tip of the diamond dresser to R ₁ from the center of the pivot shaft shown in FIG. 15 Using diamond positioning jig J2, shows the work of adjusting the distance to the tip of the diamond dresser to R ₂ from the center of the pivot shaft shown in FIG. 15

FIG. 1 shows a dressing device 1 according to an embodiment of the present invention. The dressing device 1 has a column 2 having a mounting surface 2a on a pedestal (not shown) at the lower end, a head 3 integrally provided on the upper side of the column 2, and a lower surface of the head 3. And a vertical turning shaft 5 accommodated in the provided turning shaft accommodation hole 4.

The turning shaft 5 is rotatably supported by a plurality of bearings 6 incorporated in the turning shaft accommodation hole 4. A swing shaft pulley 7 is fixed to the upper end of the swing shaft 5. The turning shaft pulley 7 is connected to a motor pulley 9 fixed to the motor shaft 8 a of the turning shaft motor 8 by a toothed belt 10, and the turning shaft motor 8 rotationally drives the turning shaft 5 via the toothed belt 10. It is supposed to be.

As shown in FIG. 2, an eccentric hole 11 is formed inside the turning shaft 5 at a position eccentric with respect to the center of the turning shaft 5. The eccentric hole 11 is opened on the lower surface of the turning shaft 5, and the turning radius changing shaft 12 in the vertical direction is accommodated in the eccentric hole 11. The turning radius changing shaft 12 is supported by a plurality of bearings 13 incorporated in the eccentric hole 11 and is rotatable around a position eccentric with respect to the center of the turning shaft 5.

A turning radius changing shaft motor 14 incorporated in the turning shaft 5 is connected to the upper end of the turning radius changing shaft 12 so that the turning radius changing shaft 12 is rotationally driven by the turning radius changing shaft motor 14. It has become. The turning radius changing shaft motor 14 is a servo motor. The servo motor is a motor that incorporates a sensor (not shown) that detects the rotation angle of the motor and performs feedback control based on the difference between the current rotation angle of the motor detected by the sensor and the target angle. When such a servo motor is used as the turning radius changing shaft motor 14, the rotation angle of the turning radius changing shaft motor 14 can be controlled extremely accurately. The turning shaft motor 8 is also a servo motor.

The lower end of the turning radius changing shaft 12 protrudes from the lower surface of the turning shaft 5, and a dresser holder 16 to which a diamond dresser 15 having a diamond fixed to the tip of the shank is detachably attached is provided at this protruding portion. The dresser holder 16 includes a crank portion 16A extending in the horizontal direction from the turning shaft 5 and a dresser mounting shaft 16B extending downward from the crank portion 16A. A dresser insertion hole 17 in the horizontal direction is formed at the lower end of the dresser mounting shaft 16 </ b> B, and the diamond dresser 15 is inserted into and fixed to the dresser insertion hole 17. Here, the diamond dresser 15 is arranged such that the direction of the tip of the diamond dresser 15 is tangential to the rotational direction of the turning radius changing shaft 12 in a cross section perpendicular to the turning radius changing shaft 12. Yes. The diamond dresser 15 can be fixed, for example, by pressing a set screw (not shown) against the side surface of the shank of the diamond dresser 15.

As shown in FIG. 6, a dresser tip detection sensor 18 is provided at a position where the tip of the diamond dresser 15 passes when the dresser holder 16 is rotated by the rotation of the turning radius changing shaft 12. The dresser tip detection sensor 18 may be a photo sensor that detects the tip of the diamond dresser 15 in a non-contact manner. However, if a touch sensor that detects whether the tip of the diamond dresser 15 is in contact is used, the diamond The tip of the dresser 15 can be detected with high accuracy.

The dresser tip detection sensor 18 may be fixed to the pedestal side to which the column 2 is attached via the sensor bracket 19 or may be fixed to the turning shaft 5 side. When fixed on the turning shaft 5 side, the positional relationship between the diamond dresser 15 and the dresser tip detection sensor 18 is constant regardless of the rotation angle of the turning shaft 5, so that the rotation angle correction operation of the turning radius changing shaft 12 described later is performed. It becomes possible to carry out with higher accuracy.

The dresser tip detection sensor 18, the turning shaft motor 8, and the turning radius changing shaft motor 14 are connected to the control device 20. The control device 20 includes a detection signal indicating whether the tip of the diamond dresser 15 has been detected from the dresser tip detection sensor 18, a position signal indicating the current rotation angle of the turning shaft motor 8 from the turning shaft motor 8, and turning. A position signal indicating the current rotation angle of the turning radius changing axis motor 14 is input from the radius changing axis motor 14. The control device 20 outputs a control signal for controlling the rotation of the motor to the turning axis motor 8 and the turning radius change axis motor 14.

Hereinafter, the forming process of the grindstone G using the dressing apparatus 1 will be described.

First, as shown in FIG. 3, the grindstone G before molding is held on the grindstone shaft 21, and the grindstone shaft 21 is rotated in this state to bring the tip of the diamond dresser 15 into contact with the surface of the grindstone G. Next, the dresser holder 16 that holds the diamond dresser 15 is turned together with the turning shaft 5. As a result, the tip of the diamond dresser 15 moves so as to draw an arc-shaped trajectory, the surface of the grindstone G is scraped along the trajectory, and the grindstone G is formed into an arc-shaped cross section. At this time, as shown in FIG. 4, the radius R ₁ of the cross-section arc of the grindstone G is the turning radius of the tip of the diamond dresser 15, that is, the distance from the center of the turning shaft 5 to the tip of the diamond dresser 15.

Here, as shown in FIG. 5, when the radius of the cross-section arc of the grindstone G to be molded is changed from R ₁ to R ₂ , it is necessary to change the turning radius of the tip of the diamond dresser 15. It is necessary to change the position of the diamond dresser 15 with respect to the center of one pivot axis 5.

The operation of changing the position of the diamond dresser 15 is performed as follows. That is, the rotation angle of the turning radius changing shaft 12 necessary for changing the turning radius of the tip of the diamond dresser 15 is calculated, and the turning radius changing shaft motor 14 is equivalent to the turning angle of the turning radius changing shaft 12. Rotate. Then, the dresser holder 16 is moved by the rotation of the turning radius changing shaft 12, the distance from the center of the turning shaft 5 to the tip of the diamond dresser 15 is changed, and the position of the diamond dresser 15 with respect to the center of the turning shaft 5 is changed. be able to.

Incidentally, when the surface of the grindstone G is cut with the diamond dresser 15, the tip of the diamond dresser 15 is worn. As this wear progresses, the turning radius of the tip of the diamond dresser 15 gradually increases, and as a result, an error may occur in the radius of the cross-section arc of the grindstone G.

Therefore, in order to correct an error due to wear of the tip of the diamond dresser 15, the rotation angle of the turning radius changing shaft 12 when the grindstone G is formed is corrected as follows. That is, first, as shown in FIG. 6, the turning shaft 5 is rotated so that the center of the turning radius changing shaft motor 14 is at a predetermined position, and in this state, the tip of the diamond dresser 15 is the dresser tip detection sensor 18. The turning radius changing shaft motor 14 is rotationally driven to the detected position. When the dresser tip detection sensor 18 detects the tip of the diamond dresser 15, the turning radius changing shaft motor 14 is stopped, and the wear of the tip of the diamond dresser 15 is worn based on the rotation angle of the turning radius changing shaft motor 14 at this time. The amount of deviation of the tip position due to is calculated. Then, the rotation angle of the turning radius changing shaft 12 is corrected according to the amount of deviation of the tip position of the diamond dresser 15.

The dressing apparatus 1 having the above configuration can change the position of the diamond dresser 15 by rotating the turning radius changing shaft 12 with the turning radius changing shaft motor 14 and controlling the rotation angle. That is, the operation of changing the position of the diamond dresser 15 with respect to the center of the turning shaft 5 can be performed by numerical control of the turning radius changing shaft motor 14 instead of manual work. Therefore, the work time for changing the position of the diamond dresser 15 is short, and a positioning error of the diamond dresser 15 hardly occurs.

Further, the dressing device 1 is configured such that the turning radius changing shaft 12 at the time of forming the grindstone G is based on the rotation angle of the turning radius changing shaft motor 14 when the dresser tip detecting sensor 18 detects the tip of the diamond dresser 15. The operation of correcting the rotation angle can be performed automatically. Therefore, it is not necessary to stop the dressing apparatus 1 once when performing an operation for correcting an error due to wear of the tip of the diamond dresser 15.

Further, when the dressing device 1 is used, as shown in FIG. 7, the locus of the tip of the diamond dresser 15 can be freely set by a combined operation of the rotation of the turning shaft 5 and the turning of the turning radius changing shaft 12. When the grindstone G is formed, the grindstone G having a free cross-sectional shape other than the arc is formed with high accuracy by performing synchronous control that changes the rotation angle of the turning radius changing shaft 12 according to the rotation angle of the turning shaft 5. can do.

Further, as shown in FIG. 8, the turning radius changing shaft 12 is rotated so that the diamond dresser 15 overlaps the center line of the turning shaft 5, and the turning shaft 5 is rotated in this state to swing the diamond dresser 15. By moving it, the grindstone G having a concave cross-sectional shape can be formed.

Further, when a grindstone shaft 21 that holds the grindstone G is provided so as to be movable in the axial direction, and a driving device (not shown) that drives the grindstone shaft 21 in the axial direction is provided, as shown in FIG. The rotating shaft 5 is rotated without moving the shaft in the axial direction, and then the rotating shaft 5 is stopped and the grindstone shaft 21 is moved in the axial direction, thereby forming a grindstone G having a cross section combining an arc and a straight line. be able to. Further, as shown in FIG. 10, the turning shaft 5 is rotated without moving the grindstone shaft 21 in the axial direction, and the combined operation combining the rotation of the turning shaft 5 and the axial movement of the grindstone shaft 21 from the middle thereof. By performing this, the grindstone G having a cross-sectional shape combining an arc and a non-arc curve can be formed.

In the above embodiment, the type of the dresser holder 16 has been described in which the diamond dresser 15 in which diamond is fixed to the tip of the shank is attached. However, as shown in FIG. 11, the rotary diamond dresser 15 in which diamond is fixed to the outer periphery of the wheel. You may employ | adopt the type of dresser holder 16 which attaches.

In the above embodiment, a servo motor is used as the turning radius changing shaft motor 14, but a motor with a rotary encoder 22 may be used as shown in FIG. In this case, the rotary encoder 22 may be connected to the control device 20 shown in FIG. 6, and a position signal indicating the current rotation angle of the turning radius changing shaft motor 14 may be input from the rotary encoder 22 to the control device 20. . The rotary encoder 22 may be external to the motor or may be built in the motor. Further, a stepping motor that rotates by an angle proportional to the number of input pulses may be used.

As shown in FIG. 13, the rotation of the turning radius changing shaft motor 14 is decelerated and transmitted to the turning radius changing shaft 12 between the rotation axis of the turning radius changing shaft motor 14 and the turning radius changing shaft 12. A reduction gear 23 can be incorporated. In this way, the rotation angle error of the turning radius change shaft 12 with respect to the rotation angle error of the turning radius change shaft motor 14 is reduced, so that the rotation angle of the turning radius change shaft 12 can be positioned with high accuracy. It becomes.

Further, as shown in FIG. 14, a clamp mechanism 24 is provided between the inner periphery of the eccentric hole 11 and the outer periphery of the turning radius changing shaft 12, and the clamp mechanism 24 prevents the turning radius changing shaft 12 from rotating. And a free state in which the rotation of the turning radius changing shaft 12 is allowed. In this way, after the rotation angle of the turning radius changing shaft 12 is positioned, the support rigidity of the diamond dresser 15 can be improved by preventing the turning of the turning radius changing shaft 12 by the clamp mechanism 24.

Examples of the clamp mechanism 24 include an air clamp in which a plurality of gripping claws that can be advanced and retracted in the radial direction by air pressure are arranged around the turning radius changing shaft 12 at intervals in the circumferential direction. In addition, a clamp boss made of a cylindrical body having a C-shaped cross section from which a part of the circumference is cut is provided so as to surround the turning radius changing shaft 12, and both ends of the C-shaped cross section of the clamp boss are connected to each other. The clamp boss may be reduced in diameter by tightening the clamp bolt, and the outer periphery of the turning radius changing shaft 12 may be gripped.

DESCRIPTION OF SYMBOLS 1 Dressing device 5 Turning axis 8 Turning axis motor 12 Turning radius change axis 14 Turning radius change axis motor 15 Diamond dresser 16 Dresser holder 18 Dresser tip detection sensor 20 Control device 21 Grinding wheel shaft 23 Reduction gear 24 Clamp mechanism G Grinding wheel

Claims

A pivot shaft (5) rotatably supported;
A turning shaft motor (8) for rotating the turning shaft (5);
A turning radius changing shaft (12) supported so as to be rotatable around a position eccentric to the center of the turning shaft (5) inside the turning shaft (5);
A turning radius changing shaft motor (14) for rotating the turning radius changing shaft (12),
A dressing apparatus provided with a dresser holder (16) to which a diamond dresser (15) is detachably attached to the turning radius changing shaft (12).
The dressing device according to claim 1, wherein a dresser tip detection sensor (18) is provided at a position where the tip of the diamond dresser (15) passes when the turning radius changing shaft (12) is rotated.
On the basis of the rotation angle of the turning radius changing shaft motor (14) when the dresser tip detecting sensor (18) detects the tip of the diamond dresser (15), the turning radius changing shaft (12) at the time of grinding wheel forming. The dressing device according to claim 2, further comprising a control device (20) for correcting the rotation angle.
The dressing device according to claim 3, wherein the control device (20) performs synchronous control to change the rotation angle of the turning radius changing shaft (12) in accordance with the rotation angle of the turning shaft (5) at the time of grinding wheel forming.
The dressing device according to any one of claims 1 to 4, wherein the turning radius changing shaft motor (14) is a servo motor.
The dressing device according to any one of claims 1 to 4, wherein the turning radius changing shaft motor (14) is a stepping motor.
The dressing device according to any one of claims 1 to 4, wherein the turning radius changing shaft motor (14) is a motor with a rotary encoder.
The dressing according to any one of claims 1 to 7, wherein a grindstone shaft (21) for holding the grindstone (G) is provided so as to be movable in the axial direction, and a driving device for driving the grindstone shaft (21) in the axial direction is provided. apparatus.
The dressing device according to any one of claims 1 to 8, further comprising a speed reducer (23) for decelerating the rotation of the turning radius changing shaft motor (14) and transmitting it to the turning radius changing shaft (12).
The clamp mechanism (24) according to claim 1, wherein a clamp mechanism (24) capable of switching between a clamped state for preventing rotation of the turning radius changing shaft (12) and a free state for allowing rotation of the turning radius changing shaft (12) is provided. The dressing apparatus in any one.
The dressing device according to any one of claims 1 to 10, wherein the dresser holder (16) is for a diamond dresser in which a diamond is fixed to a tip of a shank.
The dressing device according to any one of claims 1 to 10, wherein the dresser holder (16) is for a rotary diamond dresser in which diamond is fixed to an outer periphery of a wheel.