JP2003305658A - Grinding tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the generation of high frequency sound in machining. <P>SOLUTION: This grinding tool is provided with a main spindle 2 having a shank part 20 detachably mounted to an output shaft S of a machine tool, at the upper end, and formed with a mounting hole 2a opened downward; and a sub-spindle 3 having a cylindrical mounting shank 30 inserted in a freely advancing/retreating manner into the mounting hole 2a through a bearing 4, having a flange part 31 mounted with a grinding wheel 5, at the lower end, and formed with a through hole 3a extending in the axial direction. A locking pin 6 for locking the sub-spindle 3 to the main spindle 2 is inserted in a pair of oblong holes 30a for radially inserting through the mounting shank 30. An adjusting screw 7 is screwed with a threaded part 3b formed at the lower part of the through hole 3a. A compression spring 8 is disposed in a compressed state between the locking pin 6 and the adjusting screw 7. An oil seal 10 is provided at the lower end opening part of the mounting hole 2a of the main spindle 2 to effectively damp the vibration of the sub-spindle 3. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a grinding tool,
In detail, the spindle attached to the output shaft of the machine tool,
In a grinding tool that is provided so as to be movable back and forth with respect to the main shaft, and a counter shaft to which a grinding wheel is attached at the lower end,
Regarding the improvement of its structure.

[0002]

2. Description of the Related Art As a grinding (polishing) tool which is used by being attached to an output shaft of a machine tool such as a grinder or a machining center, a tool as disclosed in JP-A-8-243929 has been proposed.

This grinding tool is composed of a cylindrical main shaft having a mounting shaft portion mounted on the output shaft of a machine tool, and a secondary shaft mounted on the cylindrical main shaft so as to be movable back and forth in the axial direction through a ball and having a lower end mounted with a grinding wheel. It is mainly composed. The sub shaft is urged in a direction projecting from the lower end of the main shaft by the spring force of a compression spring mounted inside the sub shaft.

During grinding, the work or the main shaft is relatively moved in the horizontal direction while the auxiliary shaft is pressed against the work (workpiece) by the action of the spring force of the compression spring.

When an unbalanced load acts on the grinding wheel due to a step on the surface of the work during machining, the unbalanced load acts on the counter shaft from the grinding wheel, and as a result, the counter shaft resists the spring force of the compression spring. Retreat into the spindle. As a result, an unbalanced load acting on the grinding wheel can be absorbed, and smooth processing can be performed.

[0006]

However, in the above-mentioned conventional structure, when the spindle speed is high or the diameter of the grinding wheel is large, the auxiliary shaft to which the grinding wheel is attached violently moves laterally or vertically. It may vibrate, and as a result, a high frequency sound may be generated, and a so-called “squeal” phenomenon may occur.

When such a "squeal" phenomenon occurs, problems occur such that the machining accuracy is lowered, the desired surface roughness cannot be obtained, and the bearing of the machine tool is damaged.

The present invention has been made in view of such conventional circumstances, and an object of the present invention is to provide a grinding tool capable of preventing generation of high frequency noise during processing.

[0009]

A grinding tool according to a first aspect of the present invention comprises a spindle having a shank portion which is detachably attached to an output shaft of a machine tool at an upper end thereof, and a spindle having a mounting hole which opens downward. The mounting hole has a cylindrical mounting shaft portion that is supported by a bearing so as to be able to move forward and backward, a flange portion to which a grinding wheel is mounted is provided at the lower end of the mounting shaft portion, and a through hole that extends in the axial direction is formed. It has a counter shaft. The mounting shaft portion of the auxiliary shaft is provided with a pair of elongated holes that are arranged to face each other in the radial direction and extend in the axial direction so as to penetrate therethrough in the radial direction, and a retaining pin that penetrates each elongated hole. Both ends of the retaining pin are fixed to the spindle. A threaded portion is formed in the lower part of the through hole, and an adjusting nut is screwed into the threaded portion. One end of the adjusting nut is attached between the retaining pin and the adjusting nut inside the through hole. A compression spring is provided which is in pressure contact with and the other end is in pressure contact with the adjusting nut. A vibration suppressing member is provided for suppressing vibration of the sub shaft during grinding.

According to a second aspect of the present invention, there is provided a grinding tool having a shank portion which is detachably attached to an output shaft of a machine tool at an upper end thereof, a main shaft having a mounting hole opening downward, and a bearing in the mounting hole. And a counter shaft having a cylindrical mounting shaft portion that is supported so as to be able to move back and forth, a flange portion to which the grinding wheel is mounted is provided at the lower end of the mounting shaft portion, and a through shaft formed with a through hole extending in the axial direction. There is. A retaining bolt for preventing the auxiliary shaft from falling off the main shaft is inserted into the upper opening end of the through hole of the auxiliary shaft.The thread of the retaining bolt is screwed into the bottom wall of the mounting hole of the main shaft. I am fit. The retaining bolt is provided at the upper open end of the sub shaft so that the rotational force from the main shaft can be transmitted to the sub shaft. A threaded portion is formed at the bottom of the through hole of the counter shaft, and an adjusting nut is screwed into the threaded portion.One end of the adjusting nut is retained between the retaining bolt and the adjusting nut inside the through hole. Press it onto the bolt,
A compression spring is provided, the other end of which is pressed against the adjusting nut. A vibration suppressing member is provided for suppressing vibration of the sub shaft during grinding.

According to the first and second aspects of the invention, during the grinding process, the grinding wheel at the lower end of the auxiliary shaft is pressed against the workpiece by the action of the spring force of the compression spring. The eccentric load during machining that acts on the is absorbed by the auxiliary shaft retracting into the main shaft against the spring force of the compression spring.

Further, in this case, the vibration generated in the counter shaft during machining is effectively absorbed by the vibration suppressing member. This makes it possible to prevent high-frequency sound from being generated during processing.

According to the third aspect of the invention, the vibration suppressing member is an oil seal provided at the lower end opening of the mounting hole of the main shaft, and its lip portion is in contact with the mounting shaft portion of the counter shaft.

In this case, by providing an oil seal at the lower end opening of the mounting hole of the main shaft, the portion of the auxiliary shaft that is closer to the grinding wheel is supported by the lip portion of the oil seal. The supporting rigidity of the counter shaft can be improved, and the vibration of the counter shaft can be effectively damped by the resin or rubber portion of the oil seal.

According to another aspect of the present invention, the bearing is composed of a plurality of rolling elements and retainers that rotatably support the rolling elements, and the clearance between the outer diameter of the retainer and the mounting hole of the main shaft is 0. The vibration suppressing member is formed of a bearing which is interposed between the mounting hole of the main shaft and the mounting shaft portion of the auxiliary shaft and is coated with grease.

In this case, since the grease applied to the bearing exerts a damping action, the vibration generated on the counter shaft can be effectively damped. Moreover, in this case, the clearance between the retainer outer diameter and the spindle mounting hole is 0.05 to 0.3.
Since it is as small as mm, the vibration of the retainer itself can be suppressed, and the vibration of the auxiliary shaft is less likely to propagate to the main shaft side via the retainer.

In the invention of claim 5, the vibration suppressing member is constituted by a retaining pin or a retaining bolt whose outer periphery is sprayed with ceramic or cemented carbide.

In this case, the rigidity of the retaining member can be increased by spraying ceramics or cemented carbide on the outer circumference of the retaining pin or retaining bolt (hereinafter collectively referred to as "retaining member"). Can be improved. With this, when the vibration generated in the counter shaft propagates to the retaining member via the compression spring, the vibration of the retaining member itself is suppressed, whereby the vibration of the counter shaft can be effectively damped.

In the invention of claim 6, the grinding wheel has a cup shape that opens downward, and a standing wall that rises upward is provided at the outer peripheral edge of the mounting surface of the grinding wheel to which the flange of the counter shaft is mounted. The portion is formed along the outer circumference and a through hole penetrating in the axial direction is formed in the mounting surface.

In this case, when the grinding fluid is scattered outward by the centrifugal force caused by the rotation of the grinding wheel during the grinding process, the standing wall portion of the outer peripheral edge of the mounting surface of the grinding wheel is scattered by the grinding fluid. In addition to the prevention, the grinding fluid on the mounting surface of the grinding wheel is surely introduced onto the processing surface through the through hole in the axial direction. As a result, it is possible to prevent seizure of the grinding wheel due to insufficient grinding liquid.

By the way, the above-mentioned "squealing" phenomenon of the sub-shaft is apt to occur when a grinding wheel having a large diameter is used and further the entire surface of the grinding wheel is used for the grinding work. The large contact area of the grinding wheel with the object causes a shortage of the grinding fluid, and as a result, the grinding wheel is apt to burn.

According to the invention of claim 6, since the grinding liquid can be reliably supplied to the machining surface side, vibration generated in the counter shaft during machining can be absorbed and seizure of the grinding wheel can be prevented. become.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. [ First Embodiment ] FIG. 1 is a partially cutaway front view of a grinding tool according to a first embodiment of the present invention. As shown in the figure, this grinding tool 1 includes a rotatable spindle 2 and a spindle 2.
And a counter shaft 3 mounted so as to be capable of moving back and forth in the axial direction.

The spindle 2 has a shank portion 20 at its upper end, and the shank portion 20 is detachably attached to an output shaft S of a machine tool (not shown) such as a grinder or a machining center. There is. Further, the main shaft 2 has a mounting hole 2a that opens downward.

The counter shaft 3 has a cylindrical mounting shaft portion 30 inserted into the mounting hole 2a of the main shaft 2, and the mounting shaft portion 30
Are supported in the mounting holes 2a via bearings 4 so as to be slidable in the axial direction. A flange portion 31 to which the grinding wheel 5 is attached is provided at the lower end of the attachment shaft portion 30. Further, the mounting shaft portion 30 has a through hole 3a extending in the axial direction.
Are formed.

The mounting shaft portion 30 is formed with a pair of elongated holes 30a which are arranged to face each other in the radial direction and extend in the axial direction so as to penetrate in the radial direction. The retaining pin 6 is inserted into each of the elongated holes 30a. The retaining pin 6 has 30 slots
It extends through the main shaft 2 through a, and both ends 6a of the retaining pin 6 are fixed to through holes 2b formed in the main shaft 2. The rotational force of the main shaft 2 is transmitted to the sub shaft 3 via the retaining pin 6. Further, the auxiliary shaft 3 is allowed to move in the mounting hole 2a of the main shaft 2 in the axial direction by a slight amount due to the axial clearance formed between the retaining pin 6 and the elongated hole 30a.

A screw portion 3b is formed in the lower portion of the through hole 3a, and an adjusting nut 7 is screwed into the screw portion 3b. The adjusting nut 7 is formed with a square hole 7a having a quadrangular or hexagonal cross section.

A compression spring 8 is interposed between the adjusting nut 7 and the retaining pin 6 in the through hole 3a. One end of the compression spring 8 is in pressure contact with the retaining pin 6 and the other end is in pressure contact with the adjusting nut 7. Due to the action of the spring force of the compression spring 8, the counter shaft 2 is constantly urged downward via the adjusting nut 7.

The bearing 4 is composed of a thin-walled cylindrical retainer 40 and balls (rolling elements) 41 rotatably held in a large number of holding holes formed in the retainer 40.

The grinding wheel 5 has a cup shape having a downward opening, and a mounting member 5 having a disk-shaped grinding wheel 50 fixed to the lower surface.
Have one. The mounting member 51 is attached by the mounting screw 9.
It is fixed to the flange portion 31 of the counter shaft 3.

An oil seal 10 is attached to the lower end opening of the attachment hole 2a of the main shaft 2. Oil seal 1
The resin-made or rubber-made lip portion of No. 0 is in contact with the outer peripheral surface of the mounting shaft portion 30 of the sub shaft 3. Further, at the lower end of the mounting shaft portion 30 of the counter shaft 3, a relief 30 for polishing the mounting shaft portion 30 is provided.
b is formed.

When a workpiece is ground using the grinding tool having the above structure, the adjustment nut 7 is rotated by using the square hole 7a of the adjustment nut 7 to adjust the tightening amount of the adjustment nut 7. Adjust accordingly. As a result, the distance between the retaining pin 6 and the adjusting nut 7 changes, and the compression spring 8
The amount of deformation (shrinkage amount) can be changed, and as a result, the pressing pressure of the grinding wheel 5 against the work can be adjusted.

Next, by rotating the output shaft S and moving a table (not shown) to which the work is fixed in the horizontal direction, or by moving the output shaft S in the horizontal direction, the grinding wheel 5 is moved. The workpiece is ground by pressing it against. The unbalanced load acting on the grinding wheel 5 during the grinding process is absorbed by the auxiliary shaft 3 retracting into the mounting hole 2a of the main shaft 2 against the spring force of the compression spring 8.

In this case, the mounting hole 2a of the spindle 2
Since the oil seal 10 is provided in the lower end opening, the portion of the attachment shaft portion 30 of the auxiliary shaft 3 that is closer to the grinding wheel 5 is supported by the lip portion of the oil seal 10. As a result, the support rigidity of the sub shaft 3 can be improved,
As a result, it is possible to suppress the occurrence of vibration in the sub shaft 3. Further, in this case, even if vibration is generated in the sub shaft 3 during the grinding process, the resin or rubber portion of the oil seal 10 exhibits a damping function, so that the vibration of the sub shaft 3 is effectively damped. it can.

The clearance between the outer diameter of the retainer 40 of the bearing 4 and the inner diameter of the mounting hole 2a of the main shaft 2 is 0.
It is preferably from 05 to 0.3 mm. This is the counter shaft 3
The vibration of the retainer 40 is suppressed between the mounting shaft portion 30 and the main shaft 2, and the vibration of the auxiliary shaft 3 is transmitted through the retainer 40.
This is to suppress propagation to the side of. Further, it is preferable that grease is applied to the inner and outer peripheral surfaces of the retainer 40. This is for damping the vibration of the sub shaft 3 by viscous resistance of grease. For the same reason, the compression spring 8
It is preferable that grease is also applied to the outer periphery of the.

Further, it is preferable that ceramic or cemented carbide is sprayed on the outer periphery of the retaining pin 6.
This is to improve the rigidity of the retaining pin 6 by spraying ceramic or cemented carbide.
As a result, when the vibration generated in the counter shaft 3 propagates to the retaining pin 6 via the compression spring 8, the vibration of the retainer pin itself is suppressed, whereby the vibration of the counter shaft 3 is effectively damped. it can. As described above, it is possible to reliably prevent the generation of high-frequency sound due to the vibration of the counter shaft 3.

[ Second Embodiment ] FIG. 2 shows a second embodiment of the present invention.
FIG. 7 is a front view of the grinding tool according to the embodiment of FIG.
2, the same reference numerals as those in FIG. 1 indicate the same or corresponding portions. In the second embodiment, instead of the oil seal, the labyrinth seal 15 is provided with the main shaft 2 and the sub shaft 3.
And the point that the retaining bolt 16 is provided instead of the retaining pin.
Of the embodiment of FIG.

That is, as shown in FIG. 2, a labyrinth seal 15 is provided between the lower end surface 2c of the main shaft 2 and the upper end surface 31a of the flange portion 31 of the auxiliary shaft 3. Note that in FIG. 2, the labyrinth seal 15 is shown only on the cross-sectional side for convenience of illustration. Labyrinth seal 15
Has a plurality of lip portions formed on either side of the end faces 2c, 31a and a lip facing portion formed on the other side of the end faces 2c, 31a, and these gaps are wide and narrow. It is composed by making changes.

A retaining bolt 16 for preventing the auxiliary shaft 3 from falling off the main shaft 2 is inserted through the upper open end of the mounting shaft portion 30 of the auxiliary shaft 3, and the retaining bolt 1
The thread portion 6 is screwed into the bottom wall portion of the mounting hole 2 a of the main shaft 2. A hexagonal hole 16a for tool locking is formed in the head of the retaining bolt 16, and between the head and the screw part,
A hexagonal nut-shaped rotation stopping portion 16b is formed.

On the other hand, a collar 18 having a hexagonal hole is fixed to the upper end of the through hole 3a of the counter shaft 3, and the collar 18
The hexagonal hole of the
Are fitted. As a result, the rotational force from the main shaft 2
Locking portion 16b of retaining bolt 16 and collar 1
It is adapted to be transmitted to the sub shaft 3 via 8. Further, a hole retaining ring 17 for preventing the collar 18 from coming off is attached to the upper end of the through hole 3a of the counter shaft 3.

On the outer periphery of the retaining bolt 16, the first
Similar to the retaining pin 6 of the above embodiment, it is preferable that ceramic or cemented carbide is sprayed. Note that one end of the compression spring 8 is in pressure contact with the head of the retaining bolt 16.

In this case, by providing a labyrinth seal on the upper end surface 31a of the flange portion 31 of the sub shaft 3, a portion of the mounting shaft portion 30 of the sub shaft 3 closer to the grinding wheel 5 is supported. The supporting rigidity of the sub shaft 3 can be improved, and the vibration of the sub shaft 3 can be effectively damped by the resin or rubber portion of the labyrinth seal. Further, in this case, since the "relief" for polishing the mounting shaft portion 30 is not required at the corner of the connecting portion of the mounting shaft portion 30 and the flange portion 31 of the auxiliary shaft 3, the rigidity of the entire sub shaft is increased. And the vibration of the sub shaft 3 can be suppressed.

Further, in this case, the retaining bolt 1
The ceramic or cemented carbide is thermally sprayed on No. 6, and the rigidity of the retaining bolt 16 is improved. As a result, the vibration generated in the counter shaft 3 propagates to the retaining bolt 16 via the compression spring 8. At this time, the vibration of the retaining bolt itself is suppressed, whereby the vibration of the sub shaft 3 can be effectively damped.

[ Third Embodiment ] FIG. 3 shows the third embodiment of the present invention.
FIG. 7 is a front view of the grinding tool according to the embodiment of FIG.
3, the same reference numerals as those in FIGS. 1 and 2 indicate the same or corresponding portions. In the third embodiment, the structure of the grinding wheel is different from that of the first and second embodiments.

That is, as shown in FIG. 3, in the grinding wheel 5, the outer peripheral edge portion of the mounting surface 51a of the mounting member 51 to which the flange portion 31 of the auxiliary shaft 3 is mounted is provided with a standing wall portion 51b which rises obliquely upward. It is formed along.
Further, the mounting member 50 is formed with a through hole 51c in the axial direction, and the through hole 51c is open to the mounting surface 51a and the grindstone 50 side. Further, the mounting member 51 is fixed to the flange portion 31 of the sub shaft 3 via the mounting screw 9 arranged in the center.

In this case, during the grinding process, when the grinding fluid is about to be spattered outward by the centrifugal force due to the rotation of the grinding wheel 5, the standing wall at the outer peripheral edge of the mounting surface 51a of the mounting member 51 of the grinding wheel 5 is struck. The portion 51b prevents the grinding fluid from scattering. Then, as shown by the arrow in FIG. 3, the grinding fluid stored on the mounting surface 51 a passes through the through hole 51 c of the mounting member 51 and is introduced from above the mounting surface 51 to the grindstone 50 side below. . As a result, it becomes possible to reliably supply the grinding fluid to the processed surface, and it is possible to prevent seizure of the grinding wheel 5 due to insufficient grinding fluid.

By the way, the phenomenon of "squealing" of the counter shaft 3 is apt to occur when a grinding wheel 5 having a large diameter is used and the entire grinding surface of the grinding wheel 5 is used for grinding. In this case, the contact area of the grinding wheel 5 with respect to the workpiece becomes large, so that the grinding fluid becomes insufficient, and as a result, the grinding wheel 5 is apt to burn.

However, in the third embodiment, since the grinding liquid can be surely introduced to the processing surface side, not only the generation of high-frequency sound due to the vibration of the sub shaft 3 can be reliably prevented. Therefore, it is possible to reliably prevent the seizure of the grinding wheel 5.

In the first and second embodiments, the retainer pin and the retainer bolt are used to transmit the rotational force from the main shaft to the auxiliary shaft, respectively. The application is not limited to this.

As the retainer 40 of the bearing 4, one having a polygonal cross section such as a hexagonal cross section is used.
Each shape of the mounting hole 2a of the main shaft 2 and the mounting shaft portion 30 of the counter shaft 3 may be formed in a shape corresponding to the sectional shape of the retainer 40. In this case, the rotational force of the main shaft 2 is transmitted to the sub shaft 3 via the bearing 4.

[0051]

As described above, according to the grinding tool of the present invention, since the vibration suppressing member that absorbs the vibration generated in the counter shaft on which the grinding wheel is mounted is provided, a high frequency sound is generated during machining. There is an effect that can prevent.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of a grinding tool according to a first embodiment of the present invention.

FIG. 2 is a partially cutaway front view of a grinding tool according to a second embodiment of the present invention.

FIG. 3 is a partially cutaway front view of a grinding tool according to a third embodiment of the present invention.

[Explanation of symbols]

1: Grinding tool 2: Spindle 2a: Mounting hole 2c: Bottom surface 20: Shank part 3: Secondary axis 3a: Through hole 3b: screw part 30: Mounting shaft 30a: long hole 30b: Run away 31: Flange part 31a: upper end surface 4: Bearing 40: Retainer 41: Ball (rolling element) 5: Grinding wheel 50: Whetstone 51: Mounting member 51a: Mounting surface 51b: Standing wall 51c: Through hole 6: Locking pin 7: Adjustment nut 8: Compression spring 10: Oil seal (vibration suppression member) 16: Lock bolt S: Output shaft

Claims (6)

[Claims] 1. A grinding tool, comprising a main shaft having a shank portion removably attached to an output shaft of a machine tool at an upper end thereof, and a mounting hole opening downward, and a reciprocating movement through a bearing in the mounting hole. Having a cylindrical mounting shaft portion that is supported freely, and having a flange portion to which a grinding wheel is mounted at the lower end of the mounting shaft portion, and a counter shaft having a through hole extending in the axial direction formed, The mounting shaft portion of the counter shaft is formed with a pair of elongated holes that are arranged in opposition to each other in the radial direction and extend in the axial direction so as to penetrate in the radial direction, and a retaining pin that is inserted through each of the elongated holes. Both ends of the retaining pin are fixed to the main shaft, a threaded portion is formed in the lower portion of the through hole, an adjusting nut is screwed into the threaded portion, and inside the through hole. The retaining pin and the adjusting nut A compression spring, one end of which is in pressure contact with the retaining pin and the other end of which is in pressure contact with the adjusting nut, is provided between the two, and vibration suppression for suppressing vibration of the auxiliary shaft during grinding. A grinding tool, wherein a member is provided. 2. A grinding tool, comprising a main shaft having a shank portion removably attached to an output shaft of a machine tool at an upper end thereof, and a mounting hole opening downward, and a reciprocating movement through a bearing in the mounting hole. Having a cylindrical mounting shaft portion that is supported freely, and having a flange portion to which a grinding wheel is mounted at the lower end of the mounting shaft portion, and a counter shaft having a through hole extending in the axial direction formed, At the upper opening end of the through hole of the counter shaft, a retaining bolt for preventing the counter shaft from coming off the main shaft is inserted, and the thread portion of the retainer bolt is a bottom wall of the mounting hole of the main shaft. While being screwed into the portion, the retaining bolt is provided at the upper open end of the auxiliary shaft so as to be able to transmit the rotational force from the main shaft to the auxiliary shaft, and at the bottom of the through hole. Is formed with a threaded portion, An adjusting nut is screwed, and between the retaining bolt and the adjusting nut inside the through hole, one end is in pressure contact with the retaining bolt and the other end is in compression contact with the adjusting nut. A grinding tool, wherein a spring is provided and a vibration suppressing member for suppressing vibration of the auxiliary shaft during grinding is provided. 3. The vibration suppressing member according to claim 1 or 2, wherein the vibration suppressing member is an oil seal provided at a lower end opening of the mounting hole of the main shaft, and a lip portion of the oil seal is the mounting shaft part of the sub shaft. A grinding tool characterized by being in contact with a grinding tool. 4. The bearing according to claim 1, wherein the bearing includes a plurality of rolling elements and retainers that rotatably support the rolling elements, and the outer diameter of the retainer and the mounting hole of the main shaft. Clearance of 0.
The vibration suppressing member is composed of the bearing that is interposed between the mounting hole of the main shaft and the mounting shaft portion of the counter shaft and is greased. A grinding tool characterized by the following. 5. The vibration suppressing member according to claim 1 or 2, wherein the vibration suppressing member is formed of the retaining pin or the retaining bolt whose outer periphery is sprayed with ceramic or cemented carbide. Grinding tool. 6. The grinding wheel according to claim 1 or 2, wherein the grinding wheel has a cup shape that opens downward, and an outer peripheral edge portion of a mounting surface to which the flange portion of the counter shaft is mounted has an upper portion. A grinding tool characterized in that a rising wall portion is formed along the outer periphery and a through hole penetrating in the axial direction is formed in the mounting surface.