JPH05185359A - Endless belt processing device and grinding wheel therefor - Google Patents

Abstract

PURPOSE:To precisely polish the rear surface of an endless belt running with a certain tension by fitting an outer cylinder on one of the spindle roll and an aux. shaft roll, and installing a rotatable flange on the side of movement of the endless belt set over these two rolls. CONSTITUTION:An endless belt 4 is set over a spindle roll 2 and an aux. shaft roll 3 while a certain tension is given and is left running in the condition that the end face of the belt is contacted with a rotatable flange 36. If the endless belt 4 running is deviated in the direction of pressing the flange 36, an outer cylinder 35 fitted on the spindle roll 2 moves in the opposite direction with the reaction force to this pressing force to cause the endless belt 4 always in contact with the flange with a small contact pressure, and the belt running line is held constant at all times. If a grinding wheel 50 of the belt processing part is operated while the endless belt is running in this condition, the rear surface processing of the belt can be carried out precisely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endless belt processing apparatus and a grinding wheel used for the same, and more specifically, it constantly stabilizes the running of an endless belt such as a vulcanizing belt sleeve to process the back surface of the endless belt with high accuracy. The present invention also relates to an endless belt processing apparatus that suppresses heat generated during belt processing and performs polishing, and a grinding wheel used for the same.

[0002]

2. Description of the Related Art Conventionally, a multi-ribbed belt is disclosed in, for example, Japanese Patent Publication No.
As disclosed in Japanese Patent Publication No. 2-17552, a reverse molded body obtained by laminating a canvas, an upper rubber layer, a tensile body and a lower rubber layer on a mandrel is vulcanized, and the vulcanized sleeve obtained is used as a tubular surface portion. It is manufactured by a grinder method in which a plurality of V-shaped grooves are ground by a grinding wheel in which portions having a plurality of V-shaped grooves are connected and integrated.

Further, recently, in a long multi-ribbed belt, a vulcanized belt sleeve is hung on a driving roll and a driven roll to run, and a surface of the running belt sleeve is ground into a V groove by a grinding wheel. Being manufactured. Further, these methods are not limited to the multi-ribbed belt, and also in the low edge belt, the vulcanized belt sleeve is stretched on two rolls in the same manner to run, and is cut into a V shape by a cutter. Also, for toothed belts,
A sleeve of a vulcanized toothed belt is stretched over two rolls and the back surface of the belt is polished to finish it to a constant thickness.

By the way, in manufacturing these belts,
Usually, a rope-shaped core wire is embedded as a tension member in the belt sleeve, and when such an endless belt is hung between two rolls and run, the twisting of the core wire when the core wire is spirally wound and When the belt is processed by the grinding wheel or while the belt is being processed by the grinding wheel, or the belt sleeve is slightly separated from the belt sleeve, the belt sleeve slightly shifts due to tilting There is a problem that processing cannot be performed accurately. For this reason, conventionally, in order to prevent such a deviation while the belt is running, it has been practiced to alternately arrange Z-twisted wires and S-twisted wires in the core wire and embed them.

Further, the conventional polishing wheel has a polishing portion relatively extending in the circumferential direction between slits extending in the width direction at regular intervals in the circumferential direction. This polishing portion had convex portions having a triangular cross section at regular intervals along the width direction, and diamond was attached to the surface thereof.

[0006]

However, in the configuration of the core wire in which the Z twists and the S twists are simply alternately arranged as described above, even the deviation due to the inclination of the core wire during the continuous spiral winding It was not enough to prevent it, and when viewed as a whole, it could not be said to be sufficient to prevent the deviation while the belt was running.

Then, as a supplement to this, it was considered to use two rolls in the shape of a crown having a mountain height at the center, but in this case, the back surface of the belt sleeve suspended between both rolls is also used. Similarly, it becomes a crown,
On the contrary, there was a problem that an accurate linear V groove could not be processed.

Another problem is that the conventional polishing wheel has a large length of the polishing portion along the circumferential direction.
When the belt sleeve is processed, a large amount of heat is generated in the sleeve, which causes vulcanization and reversion, which makes it impossible to perform accurate processing, and also consumes a large amount of power during processing. In view of the above situation, the present invention copes with this situation and improves the structure of the roll that stretches the belt to prevent the endless belt such as a belt sleeve from running eccentrically, thereby ensuring an accurate running line. The purpose of this is to ensure that the back surface of the belt is polished, suppress heat generation with a low load, and perform the processing accurately at high speed.

[0009]

That is, a feature of the present invention which meets the above-mentioned object is to provide at least a main shaft roll and a sub shaft roll for hanging an endless belt and running the belt under a predetermined tension. A belt running part, wherein one end of each roll is fixed and the other end is detachable by a detaching member, and the belt running part is disposed adjacent to the belt running part.
An endless belt processing apparatus comprising a belt processing section having a grinding wheel for grinding V-grooves on a back surface of a running endless belt, wherein at least one roll of the belt traveling section rotates with an axis and has an axial direction. And a belt biasing device in which at least one fixing flange rotatable with the traveling of the belt is arranged on the one end fixed side of the roll of the outer cylinder. The grinding wheel of the belt processing section comprises a plurality of polishing sections protruding at regular intervals along the circumferential direction thereof, and the polishing sections have rib sections at a constant pitch along the width direction thereof. It is in the belt processing device.

A grinding wheel for polishing a groove portion on the back surface of an endless belt, which is another invention, is a grinding wheel for belt processing for polishing a groove portion on the surface of an endless belt. A plurality of polishing portions protruding at a constant pitch along the circumferential direction on the surface and groove-shaped slit portions located between the polishing portions are provided, and rib portions and concave portions are provided along the width direction of the polishing portion. Are alternately arranged, and particulate matter is attached to at least the rib portion of the polishing portion, the surface of the concave portion and the edge of the rib portion, while forming a fluid passage communicating with the vicinity of the polishing portion inside the grinding wheel. An accommodating portion into which a shaft having a fluid passage is fitted is provided.

[0011]

In the apparatus for processing an endless belt of the present invention, the endless belt is stretched on the main shaft roll and the sub shaft roll under a predetermined tension, and the end face of the belt is run in contact with the rotatable flange. .. Then, if the endless belt travels and is biased in the direction of pressing the flange, this pressing force causes the outer cylinder fitted to the spindle roll to move in the opposite direction due to the reaction of this force, and the endless belt is always small. It will come into contact with the flange due to the pressing force and keep the belt running line constant. Therefore, when the endless belt runs in such a state, the back surface of the belt can be accurately processed when the grinding wheel of the belt processing unit is operated.

Moreover, in the grinding wheel of the present invention, the edge of the polishing section and the area in the vicinity thereof mainly have the function of grinding the endless belt, so that the length of the polishing section can be shortened, The rotation load of the grinding wheel can be reduced to suppress the heat generation of the endless belt, and high-speed rotation can be performed quickly and accurately. Further, the groove-shaped slit portion provided between the polishing portions serves as a region for temporarily releasing the stress applied to the surface to be ground of the endless belt during processing and restoring the deformation. As a result, the surface to be ground is processed again in the polishing section without leaving any distortion, enabling highly accurate grinding.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 4 are diagrams mainly relating to an endless belt processing apparatus of the present invention, and FIGS. 5 to 9 are diagrams relating to a grinding wheel used in the endless belt processing apparatus. In the figure, reference numeral 1 denotes the entire processing apparatus for an endless belt, and reference numerals 2 and 3 denote an endless belt 4 made of vulcanized or unvulcanized rubber or thermoplastic elastomer, which is run under a predetermined tension. Spindle roll,
The counter shaft rolls are shown respectively. Then, the processing apparatus 1 for an endless belt of the present invention suspends the endless belt 4 on at least the main shaft roll 2 and the sub shaft roll 3 under a predetermined tension,
It is composed of a belt traveling unit 5 for traveling and a belt deviation prevention unit 6.

Of these, the belt running unit 5 is the main shaft roll 2
And the auxiliary shaft roll 3 are arranged in parallel with each other, and the main shaft roll 2
A part of the main spindle 7 is rotatably arranged on a main spindle roll base 9 fixed to a base 8 through a spinning body 10, and an end portion thereof is supported by a main spindle attaching / detaching member 12 which can be fitted to the main spindle roll 2. Has been done. Similarly, one end of the counter shaft roll 3 is attached to the counter shaft roll base 14 arranged on the tension base 13 to rotate the idle body 1.
5 is rotatably arranged, and its end is supported by a counter shaft detaching member 16 that can be fitted to the counter shaft roll 3.

The spindle attaching / detaching member 12 supports and fixes the end of the spindle roll 2 and can be detached from the end, so that the rod 19 inserted in the bearing 18 can be moved by the operation of the cylinder 20. ing. At the tip of the rod 19, a groove 2 provided on the end surface of the spindle roll 2 is provided.
1. Conical end 22 and rod 19 that fit together to align cores
And a tubular portion 24 arranged on the outer circumference of the tailstock 23 that can be idled.

The cylindrical portion 24 can be fitted into the outer peripheral surface of the end portion of the spindle roll 2, and the outer peripheral surface of the tail stock 23 is connected to the cylinder 26 via a slidable ring body 25 so as to be slidable. ing. Further, the spindle detachable member 1
In FIG. 2, 2 is rotated together with the arm 27 around the axis in the direction of the arrow to facilitate the attachment and removal of the endless belt 4 to the roll. On the other hand, also in the auxiliary shaft attaching / detaching member 16, the rod 19 inserted in the bearing 18 is movable by the operation of the cylinder 20, and moreover, it is rotatable in the arrow direction in the figure.

Therefore, the endless belt 4 such as a belt sleeve having a core wire such as a cord embedded therein is attached to the main shaft roll 2
Further, since the main shaft roll 2 and the sub shaft roll 3 are hung on the sub shaft roll 3 and are attached to and removed from these rolls, the detachable members 12 and 16 of the main shaft roll 2 and the sub shaft roll 3 are swiveled.

The tension base 13 on which the counter shaft roll 3 is installed is placed on two rails 28, 28 provided on the base 8 and moved by a rod 30 connected to a tension cylinder 29. And endless belt 4
It is configured to apply tension to. The rotation of the spindle roll 2 is transmitted to the rotation of the drive unit 31 installed on the base 8 via, for example, the toothed belt 32. The belt running unit 5 is not limited to the main shaft roll 2 and the sub shaft roll 3, but other rolls such as tension rolls may be used.

Next, one of the present invention is applied to the belt running unit 5.
The belt deviation prevention portion 6 which is one of the main parts is fitted with an outer cylinder 35 which rotates with the shaft and is movable in the axial direction on one of the rolls 2 and 3, that is, the main shaft roll 2 in this embodiment. At the same time, the endless belt 4 abuts against the endless belt 4 and is provided with a flange 36 for preventing the movement thereof.

That is, the main shaft roll 2 becomes a spline shaft except both ends thereof, a plurality of keys provided in the axial direction are provided in the circumferential direction, and an outer cylinder 35 movable in the axial direction is fitted on the outside thereof. ing. The outer cylinder 35 rotates together with the main shaft roll 2 and is movable in the axial direction.

At one end of the outer cylinder 35, a fixing flange 36 is fitted on the outer surface with a slight clearance from the outer cylinder 35, and the spindle roll base 9 is provided with an idle body 3.
8 is rotatably attached to the endless belt 4. The fixing flange 36 comes into contact with the side wall 37 of the endless belt and rotates as the belt 4 travels, and the reaction of the pressing force generated by the deviation of the endless belt 4 is removed. The outer cylinder 35 is moved by transmitting it to the cylinder 35.

The fixing flange 36 may be located at the end of the main shaft roll 2, the end of the counter shaft roll 3, or between the main shaft roll 2 and the counter shaft roll 3, but as shown in the figure, the main shaft roll 2 is shown. Most preferably it is located at the end of. This is because, among other things, the reaction of the endless belt 4 to the biasing force is sensitively transmitted to the outer cylinder 35 to move the outer cylinder 35.

On the other hand, at the end of the spindle roll 2, the cylinder portion 24 of the spindle detaching member 12 is fitted into the outer periphery of the spindle roll 2, and the end portion of the outer cylinder 35 is pressed by the cylinder 26 at a predetermined pressure. Is as described above, and the outer cylinder 35
As the cylinder moves, the cylindrical portion 24 also retracts.

Although the outer cylinder 35 is fitted only on the outer circumference of the main shaft roll 2 in the figure, it can be fitted on the outer circumference of the auxiliary shaft roll 3 or both rolls. You can also

Further, in the figure, the side wall 37 of the endless belt 4 is brought into contact with the fixed flange 36, and the outer cylinder 35 is brought into contact with the tip of the cylindrical portion 24 of the main shaft attaching / detaching member 12, but this is the outer cylinder. This is to prevent a slight movement of 35 in the axial direction, that is, shake.

Further, in FIG. 1, reference numeral 40 denotes a belt processing portion, for example, a processing portion 40 for V-groove polishing of a multi-ribbed belt.
The processing section 40 includes an X-axis movable base 41 that moves in parallel with the axis of the main shaft roll 2 and a Y-axis that moves in the direction perpendicular to the X-axis movable base 41 and is installed on the X-axis movable base 41. It has a movable base 42. The X-axis movable base 41 is fitted to a slide base 44 provided on the support base 43, and a shaft 46 connected to an X-axis pulse motor 45 is fitted therein. Further, the Y-axis movable table 42 is fitted with a slide base 47 provided on the X-axis movable table 41, and a shaft 49 connected to a Y-axis pulse motor 48 in order to move back and forth in the main shaft roll 2 direction.
Has been inserted. The Y-axis movable base 42 is equipped with a grinding wheel 50 having a plurality of grooves and a prime mover 52 for rotating the grinding wheel 50 via a belt 51.

Therefore, in the processing section 40, first, the rotating grinding wheel 50 is installed at a predetermined position of the endless belt 4 by the operation of the X-axis pulse motor 45, and then,
The grinding wheel 5 is driven by the operation of the Y-axis pulse motor 48.
0 is close to the endless belt 4 and V-groove processing is performed, the Y-axis movable table 42 is returned to the original position, and the X movable table 41 is again formed.
Is moved in the width direction of the endless belt by a predetermined pitch.

As shown in FIGS. 5 to 10, the grinding wheel 50 is alternately provided with polishing portions 55 projecting at a constant pitch L along the circumferential direction, and the polishing portions 55 are arranged in the width direction and Rib portions 56 and concave portions 57 having a triangular cross section are alternately provided at a constant pitch along an oblique direction with respect to the rotation axis of the grinding wheel 50. The rib portion 56 and the concave portion 5
The granular material 67 made of diamond or the like is attached to the surface of 7, and at the same time, it is also attached to the tip surface 69 including the edge 68 in the rib portion 56 of the polishing portion 55, that is, the surface contacting the endless belt 4. There is. In the present invention,
The polishing section 55 may be parallel to the rotation axis. The groove-shaped slit portion 71 provided between the polishing portions 55 is
This is a region where the stress received by the ground surface of the endless belt is once released and the deformation is restored. As a result, the surface to be ground is processed again by the polishing section 55 without leaving any distortion, which enables highly accurate grinding.

The circumferential length P of each polishing section 55 corresponds to about 10 to 50% of the pitch length L (L = P + D) of the polishing section 55. If it exceeds 50%, the rotational load of the grinding wheel is gradually increased and the endless belt 4 is likely to generate heat, and high-speed rotation cannot be expected to perform accurate machining. On the other hand, when the number is less than 10, the rotational load of the grinding wheel does not decrease so much, and rather the polishing area becomes small, which causes a problem that machining time is required. The most preferable range of the circumferential length of the polishing section 55 is about 30 to 40% of the pitch length L of the polishing section 55. In addition, the slit portion 71
The length D in the circumferential direction is equal to the pitch length L of the polishing portion 55, which is 9
This corresponds to about 0 to 50%, whereby the stress applied to the surface to be ground can be released once and a margin can be given to restore the deformation.

FIG. 10 shows another shape of the polishing section 55. The tip surface 69 of the rib section 56 of the polishing section 55 is inclined to increase the occupied area. This is edge 68
There is an effect of increasing the amount of the particulate matter 67 adhering to the vicinity and extending the life of the polishing section 55. The inclination angle of the tip surface 69 is about 45 ° at maximum, and beyond this, the biting of the endless belt 4 is deteriorated and the grinding efficiency is deteriorated.

Inside the grinding wheel 50, fluid passages 58 are provided in the vicinity of the outer peripheral portion at regular intervals along the circumferential direction, but cap bodies 63, 63 are provided on both side portions of the wheel 50. By installing it, the above-mentioned fluid passage 5
8 communicates. A housing portion 70 into which the shaft 65 is fitted is provided inside the wheel 50. This housing part 70
The shaft 65 fitted into the shaft has a plurality of fluid passages 59 for supplying a cooling medium such as water into the grinding wheel 50 in the axial direction.
have. That is, the cooling medium is the inflow passage 5 of the shaft.
9 through the pipe 60 to the inlet 61, from the inlet 61 to the fluid passage 58, and after circulating in the grinding wheel 50, to the outlet (not shown) and from the outlet to the outlet passage in the shaft. It is discharged to the outside through 62. As a result, the cooling medium circulates in the grinding wheel 50 and cools the polishing section 55 that has generated heat during processing.

When the rotating grinding wheel 50 comes into contact with the running endless belt 4, the edge 68 to which the granular material 67 is attached and the polishing portion 55 having a short circumference bite into the endless belt 4 to cut it. After that, the slit portion 71 once releases the stress applied to the surface to be ground of the endless belt 4 and becomes a region where the deformation is restored, so that the rotation load at this time becomes small and the endless belt 4 does not generate much heat. The ground surface is processed again by the polishing section 55 without leaving any distortion, which enables highly accurate grinding. Therefore, the grinding wheel 50 has a low load and a high speed, and the endless belt 4 can be ground quickly and accurately.
It should be noted that the grinding wheel 50 can be attached to any device as long as it is a device that grinds groove portions on the ventral surface or the back surface of the endless belt 4, and is not limited to the processing device for the endless belt.

The operation of the endless belt processing apparatus 1 and the grinding wheel 50 will be described below based on the above construction. First, the auxiliary shaft roll 3 is brought closer to the main shaft roll 2 side by the operation of the tension cylinder 29, and the main shaft attaching / detaching member. 12 and the auxiliary shaft attaching / detaching member 16 are separated from the rolls 2 and 3 and rotated.

Then, the endless belt 4 is hung on the main shaft roll 2 and the sub shaft roll 3, the main shaft attaching / detaching member 12 and the sub shaft attaching / detaching member 16 are rotated to the original state, and the rod 19 is moved to move each roll 2 3 is supported and fixed. In this case, the cylinder portion 24 of the spindle detaching member 12 is brought into contact with the outer cylinder 35 fitted to the spindle roll 2, and the endless belt outer side 37 is brought into contact with the flange 36.

Then, the auxiliary shaft roll 3 is replaced with the main shaft roll 2
After a predetermined tension is applied to the endless belt 4 by moving the endless belt 4 in a direction indicated by an arrow in the drawing, the drive unit 31 is operated.

At this time, when the endless belt 4 is biased toward the fixed flange 36 side, the outer cylinder 35 moves to the opposite side against this bias, so that the force pressing the fixed flange 36 of the endless belt 4 is a constant value. Therefore, the belt travels while maintaining a substantially constant belt travel line. At the same time, the belt processing unit 40 is operated to polish the back surface of the endless belt 4.

The direction in which the endless belt 4 is biased largely depends on the winding direction of the core wire. Therefore, the belt 4 must be installed on the roll so as to be biased toward the flange 36 side. Therefore, it is necessary to mark one of the side walls of the endless belt or to make a judgment based on the state of the cut surface.

When the endless belt 4 is taken out from the main shaft roll 2 and the sub shaft roll 3, especially when the main shaft roll 2 and the main shaft attaching / detaching member 12 are separated, as shown in FIG. Rod 1
9 moves and separates from the spindle roll 2, and the tubular portion 24 also separates from the spindle roll 2.

As described above, in the processing apparatus for an endless belt of the present invention, the biasing force of the endless belt 4 is released and the traveling state is always maintained stably. It can be processed. Moreover, the grinding wheel 5 used in the belt processing unit 40
No. 0 grinds at the edge of the polishing section and in the vicinity thereof, so that the polishing section 55 can be made short, the endless belt 4 can be ground with a small rotation load, and heat generation of the belt can be suppressed. It has a feature that the endless belt 4 can be accurately processed by rotating to form a V groove.

[0040]

As described above, in the apparatus for processing an endless belt according to the present invention, at least one of the above-mentioned rolls is run under a predetermined tension by hanging the belt sleeve on at least the main roll and the sub-roll. An outer cylinder that rotates together with and is movable in the axial direction is fitted, and at least one rotatable flange is arranged on the moving side of the endless belt. Even if the belt is biased during running, the belt presses the fixing flange, and this pressing force moves the spindle roll in the opposite direction due to the reaction of this pressing force, so that this pressing force decreases, and the endless belt thrust force. Since it can be run with the belt running line accurately held without being hit, it is possible to accurately grind the back surface of the belt. Ukoto has an excellent effect that can. Further, in the grinding wheel of the present invention, the endless belt is ground at the edge of the polishing section and in the vicinity thereof, whereby the length of the polishing section can be shortened and the rotational load of the grinding wheel can be reduced. The heat generated by the endless belt can be suppressed and high-speed, high-precision processing can be performed.

[Brief description of drawings]

FIG. 1 is a plan view of a processing apparatus for an endless belt according to the present invention.

FIG. 2 is a schematic side view of FIG.

FIG. 3 is an explanatory view showing a state in which a spindle detaching member is detached from a spindle roll.

4 is a cross-sectional view taken along the line AA of FIG.

FIG. 5 is a cross-sectional view of a grinding wheel used for a belt processing unit.

6 is a sectional view taken along line BB of FIG.

FIG. 7 is a sectional view taken along line CC of FIG.

FIG. 8 is a partial plan view of FIG.

FIG. 9 is a partial perspective view of a polishing portion of a grinding wheel.

10 is an enlarged view of a portion E in FIG.

[Explanation of symbols]

 1 Endless Belt Processing Device 2 Spindle Roll 3 Spindle Roller 4 Endless Belt 5 Belt Traveling Part 6 Belt Deviation Prevention Part 7 Spindle 12 Spindle Removal Member 16 Spindle Removal Member 24 Cylinder 35 Outer Cylinder 36 Fixed Flange 37 Sidewall 40 Belt Processing Part 50 Grinding wheel 55 Polishing part 56 Rib part 58 Fluid passage 59 Fluid passage 67 Granules 68 Edge 69 Tip surface 70 Housing part 71 Slit part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Shoichi Iwaki 4-1-21, Hamazoe-dori, Nagata-ku, Kobe Mitsuboshi Belt Co., Ltd.

Claims (7)

[Claims] 1. An endless belt is provided, and at least a main shaft roll and a sub shaft roll are provided for running the belt under a predetermined tension. One end of each roll is fixed and the other end is detached. An endless belt comprising: a belt running part that is detachable by a member; and a belt processing part that is disposed adjacent to the belt running part and that has a grinding wheel that grinds in a V groove on the back surface of the running endless belt. In the processing apparatus, at least one roll of the belt running unit is fitted with an outer cylinder that rotates with an axis and is movable in the axial direction, and a belt runs on one end fixed side of the roll of the outer cylinder. A belt biasing device having at least one fixed flange rotatable therewith is mounted, and further the grinding wheel of the belt processing section is arranged in its circumferential direction. An apparatus for processing an endless belt, comprising: a plurality of polishing portions that project at regular intervals along the polishing portion, the polishing portions having rib portions at a constant pitch along the width direction thereof. 2. The apparatus for processing an endless belt according to claim 1, wherein the rotatable fixing flange is arranged on the fixed side of the main shaft roll and fitted in the outer surface of the outer cylinder. 3. The spindle detaching member is provided with a movable tubular portion that presses the end face of the outer barrel fitted to the spindle roll.
Endless belt processing device described. 4. A grinding wheel for grinding a groove on a surface of an endless belt for grinding a belt, and a grinding portion which is projected on the surface of the grinding wheel at a constant pitch along a circumferential direction, and the grinding portion. While providing a groove-shaped slit portion located between the rib portion and the concave portion are alternately arranged along the width direction of the polishing portion, at least the rib portion of the polishing portion and the surface of the concave portion and the edge of the rib portion. The grinding wheel is characterized in that a granular material is attached thereto, and on the other hand, a fluid passage communicating with the vicinity of the polishing portion is formed inside the grinding wheel, and an accommodating portion into which a shaft having the fluid passage is fitted is provided. 5. The circumferential length of each polishing portion is 10 to 50 of the pitch length L of the polishing portions arranged along the circumferential direction.
The grinding wheel according to claim 4, which is%. 6. The grinding wheel according to claim 4, wherein the particulate matter is also attached to the tip surface of the rib portion of the polishing portion. 7. The grinding wheel according to claim 4, wherein the front end surface of the rib portion of the polishing portion is inclined.