JP2000084858A - Cup type rotating grinding wheel with through hole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively achieve the discharge of chips or the supply of grinding fluid to improve the cutting sharpness in a cup type rotating grinding wheel. SOLUTION: A through hole 13 for connecting the outer peripheral edge 11a of a base metal 11 to a grinding material layer 12 is provided, and chips are discharged through the through hole 13, and grinding fluid is supplied through the through hole. In this case, when the discharge of chips is regarded as important, the inner wall of the through hole 13 is inclined to the rear side in relation to the direction of rotation of the grinding wheel, and thus the discharge of chips is improved. When the supply of grinding fluid is regarded as important, the inner wall of the through hole 13 is inclined to the front side, and thus the supply of grinding fluid is improved. Further, the area of contact with an object to be ground becomes smaller to improve the cutting sharpness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cup-type rotary grindstone used for grinding a surface of stone, concrete or the like.

[0002]

2. Description of the Related Art Conventionally, cup-type rotary grindstones have been widely used for grinding stones, concrete, blocks, bricks and other highly brittle materials. The basic structure of a cup-type rotary grindstone is one in which an abrasive layer is provided continuously or intermittently along the outer periphery of a cup-shaped base metal. Surface grinding is performed by sliding on the surface.

A rotating grindstone provided with an abrasive layer continuously along the outer peripheral edge of a cup-shaped base metal has less vibration during grinding because the continuous abrasive layer contacts the workpiece. Less chipping. Further, it has the advantages that the ground surface roughness is fine and the surface accuracy is good. On the other hand, due to poor discharge of cuttings, clogging is likely to occur, and since the contact area with the workpiece is large, grinding burn is likely to occur. It also has the disadvantage that it is difficult to supply grinding fluid and cooling air.

A rotating grindstone provided with an abrasive layer intermittently along the outer peripheral edge of a cup-shaped base metal has good discharge of cuttings between the intermittent abrasive layers and is less likely to be clogged. Further, since the contact area with the material to be ground is small, there is an advantage in that the abrasive material layer has a good bite into the material to be ground and has excellent sharpness. On the other hand, it has disadvantages that vibration during grinding is large, chipping is large, and surface roughness is rough.

In these cup-type rotary grindstones, the abrasive grains forming the abrasive material layer include A-based abrasive grains mainly composed of alumina oxide, C-based abrasive grains mainly composed of silicon carbide (SiC), and CBN grains. (Cubic boron nitride) abrasive grains, diamond abrasive grains and the like are used depending on the material of the workpiece and the grinding conditions.

[0006] As described above, the rotating grindstone provided with the abrasive layer continuously along the outer peripheral edge of the base metal is liable to be clogged due to poor discharge of cuttings, and is difficult to grind. Due to the large contact area with the material, there are disadvantages that grinding burns are liable to occur, that the abrasive material layer does not easily bite into the material to be ground, resulting in poor sharpness, and that it is difficult to supply a grinding fluid or cooling air.

Several improvements have been attempted to eliminate such disadvantages, for example, Japanese Utility Model Application Laid-Open No. 61-785.
No. 67 discloses a rotary grindstone having a plurality of small holes formed in a flange portion. According to this rotating grindstone, dust is not discharged from the small holes to the collar portion during grinding, and clogging does not occur. In addition, since the air flows through the small holes, the flange portion is cooled, and as a result, the grindstone is separated by heat. Does not occur.

Japanese Patent Application Laid-Open No. Hei 8-25227 discloses that
A rotating grindstone in which a plurality of slits penetrating the back surface of the abrasive layer is formed is disclosed. According to this rotary grindstone, clogging due to chips can be reduced.

Further, the present applicant has disclosed in Japanese Patent Application Laid-Open No. Hei 6-23674.
Japanese Patent Application Laid-Open Publication No. H11-15083 proposes a rotary grindstone provided with a through-hole for introducing a grinding fluid into the inside of a peripheral wall of a base metal on a bottom wall of the base metal. According to this rotating grindstone, the grinding fluid can be effectively introduced into the grindstone.

[0010]

However, the rotary grindstone described in Japanese Utility Model Laid-Open No. 61-78567 has no inclination with respect to the rotation direction on the inner wall of the small hole, that is, because there is no rake angle, the cutting in the rear direction is performed. There is a problem that the discharge of the powder and the inflow of the grinding fluid from the back direction are not sufficient.

[0011] Further, in the rotary grindstone described in Japanese Patent Application Laid-Open No. H8-25227, a plurality of slits are formed from the outer periphery of the abrasive layer to the center, so that the abrasive layer may be damaged. Also, since this slit has no rake angle,
There is a drawback that the chips are not sufficiently discharged in the back direction or the inflow of the grinding fluid from the back direction is not sufficient.

Further, in the rotary grindstone described in JP-A-6-23674, the through-hole is formed only in the base metal, and the through-hole is not directly involved in the grinding surface. As the size increases, there is a disadvantage that the effect of introducing the grinding fluid is weakened.

The problem to be solved by the present invention is to achieve more effective discharge of cutting chips and introduction of a grinding fluid in a cup-type rotary grindstone, while at the same time improving sharpness.

[0014]

SUMMARY OF THE INVENTION A cup-type rotary grindstone according to the present invention is a cup-type rotary grindstone in which an abrasive material layer is continuously or intermittently attached along the outer peripheral edge of a cup-type die. An opening that penetrates the peripheral edge and the abrasive layer is provided at a plurality of locations in the circumferential direction of the continuously attached abrasive layer, or provided for each of the intermittently attached abrasive layers. A cup-type rotary grindstone with through holes, characterized in that the inner wall is inclined rearward or forward in the rotational direction of the grindstone.

By providing an opening penetrating the outer peripheral edge of the base metal and the abrasive material layer, it is possible to discharge chips and supply a grinding fluid through this opening. In this case, the shape of the opening can be set to an optimal shape depending on whether the emphasis is on chip discharge or the supply of grinding fluid.

When emphasis is placed on the discharge of cuttings, the shape is such that the rake angle of the opening during grinding is in the range of 40 to 90 °. Here, the rake angle is the inclination angle θ of the inner wall of the opening with respect to the grinding wheel rotation direction indicated by the arrow A in FIG. 4, and when emphasis is placed on chip discharge, as shown in FIG.
When the inner wall of the opening is inclined rearward in the direction of rotation of the grindstone when the rake angle θ is in the range of 40 to 90 °, the flow of the chips becomes as shown by the arrow B, and the discharge of the chips becomes good.

If the rake angle θ exceeds 90 °, that is, if the inner wall of the opening is inclined forward with respect to the direction of rotation of the grindstone, the chip discharge performance is poor, and the rake angle θ is greater than 40 ° and When inclined, the length of the opening becomes longer, and the centrifugal force generated by the rotation of the grindstone makes it easier for chips to accumulate on the inner wall surface on the outer peripheral side of the opening, and the strength of the abrasive material layer decreases.

On the other hand, when importance is attached to the supply of the grinding fluid, the shape is such that the rake angle of the opening at the time of grinding falls within the range of 90 to 140 °. Here, that the rake angle is larger than 90 ° indicates a state in which the inner wall of the opening is inclined forward with respect to the grinding wheel rotation direction as shown in FIG. Rake angle θ is 90-1
When the inner wall of the opening is inclined forward in the grindstone rotation direction within a range of 40 °, the flow of the grinding fluid becomes as shown by the arrow C, and the supply of the grinding fluid is improved.

If the rake angle θ is smaller than 90 °, that is, if the inner wall of the opening is inclined rearward with respect to the rotating direction of the grinding wheel, the discharge performance of the chips becomes good, but the supply of the grinding fluid is inferior. When the rake angle θ exceeds 140 ° and is largely inclined forward, the strength of the abrasive layer decreases.

Here, by providing a plurality of openings at positions on non-concentric circles, the wear shape of the abrasive layer can be kept flat, and the discharge of cutting chips and the supply of the grinding fluid can be made uniform. be able to. Also, a method of forming an opening for penetrating the outer peripheral edge of the base metal and the abrasive material layer is a method of forming the same through hole at the same position of the outer peripheral edge of the base metal and the abrasive material layer, A method in which a groove is formed and a through hole is formed at the position of the outer peripheral edge of the base metal communicating with the groove can be adopted.

The opening not only improves the discharge of cutting chips and the supply of the grinding fluid, but also contributes to improving the sharpness of the grinding wheel by reducing the contact area between the abrasive layer and the workpiece.
Furthermore, the outer peripheral edge of the base metal and the surface area of the abrasive material layer increase, thereby contributing to the improvement of the heat dissipation of the grindstone.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a front view of a cup-type rotary grindstone according to an embodiment of the present invention, FIG.
3A is a cross-sectional view taken along line AA in FIG. 1, and FIG.
FIG. 4 is a cross-sectional view taken along line B.

The rotating grindstone 10 is formed by attaching an annular abrasive layer 12 using diamond abrasive grains to the outer peripheral edge 11a of a cup-shaped base metal 11 by brazing. The base metal 11 is a base metal having a dish-shaped overall shape, and is provided with a mounting hole 11b at the center of the bottom for mounting on a rotating shaft of a power tool. The dimensions of each part of the whetstone are
100 mm outer diameter of base metal 11, radial width 2 of abrasive layer 12
0 mm and a thickness of 4.5 mm.

The rotating grindstone 10 of the present embodiment is designed to emphasize the discharge of chips, and in order to discharge chips efficiently during grinding, the outer peripheral edge 11a of the base metal 11 and the abrasive layer 12 are removed.
Are provided in the circumferential direction.

The through-hole 13 is provided with a through-hole 13a and a through-hole 13b each having a diameter of 6 mm at the same position on the outer peripheral edge 11a of the base metal 11 and on the abrasive material layer 12, so that the through-holes 13 communicate with each other. As shown in FIG. 3B and FIG. 4 which is a partial sectional view at the time of grinding, the through-hole 13 has a shape in which the rake angle of the through-hole 13 at the time of grinding is 60 °.

As described above, the through-hole 13 communicating with the outer peripheral edge 11a of the base metal 11 and the abrasive material layer 12 is provided, and the inner wall of the through-hole 13 is positioned rearward with respect to the grinding wheel rotation direction A during grinding. Due to the inclination, the flow of the swarf at the time of grinding becomes as shown by the arrow B, and the swarf is discharged well.

Further, by providing the through-holes 13b in the abrasive layer 12, the contact area with the workpiece W is reduced, and the sharpness is improved. Further, the outer peripheral edge 11 of the base metal 11
Since a and the surface area of the abrasive layer 12 are increased, the heat dissipation is improved.

In the above-mentioned rotary grinding wheel 10, the inner wall of the through-hole 13 is inclined backward with respect to the grinding wheel rotation direction while emphasizing the discharge of cutting chips. As shown in FIG. 5, the supply of the grinding fluid can be improved by inclining the inner wall of the through hole 13 forward with respect to the grinding wheel rotation direction. In any case, if the suction port of the dust collecting device is provided so as to face the through hole 13, the dust collecting effect of the dust collecting device can be enhanced.

In the above-described rotary grinding wheel 10, the base metal 11
Through hole 13a in outer peripheral edge 11a and through hole 1 in abrasive material layer 12
3b is communicated with the through hole 13 to form the through hole 13. For example, an appropriate number of radial grooves may be formed in the abrasive layer 12, and the through hole communicating with the groove may be provided in the outer peripheral edge 11a of the base metal 11. An opening for penetrating the outer peripheral edge 11a of the base metal 11 and the abrasive material layer 12 can be formed.

Further, the above-mentioned rotary grindstone 10 is provided with the abrasive layer 1
2 is a grindstone provided continuously on the outer peripheral edge 11a of the base metal 11, but the abrasive material layer is provided intermittently along the outer peripheral edge of the base metal, and the outer peripheral edge of the base metal is provided for each abrasive material layer. A grindstone configured to form an opening for penetrating the abrasive layer may also be used.

FIG. 6 is a plan view showing another example of the arrangement of the abrasive material layer and the openings. Each abrasive material layer 22 divided into four by radial grooves 24 is shown in FIG.
2 shows an example in which four through holes 23 are provided.

[Experimental Example] In order to confirm the effect of the present invention, the same specifications as the rotary grindstone 10 except that the rotating grindstone 10 (product of the present invention) shown in FIG. A grinding experiment was performed using a rotary grindstone (comparative product). The grinding conditions are as follows. Grinding conditions-Grinding machine: portable power tool-Material to be ground: concrete-Grinding time: 5 minutes x 6 times = 30 minutes-Grinding method: manual

FIG. 7 shows the grinding result. The horizontal axis in FIG. 7 represents the number of times of grinding, and the vertical axis represents the amount of grinding (g). As can be seen from FIG. 7, the grinding amount per grinding (5 minutes) is larger in the product of the present invention, and the reduction amount of the grinding amount due to the increase in the number of grindings is smaller in the product of the present invention. There is a difference of about 1.2 times in the total grinding amount between the product of the present invention and the comparative product.

FIG. 8 is a diagram showing the state of wear of the abrasive material layer after further grinding for 90 minutes. In the case of the comparative product, as shown in (b) of the figure, the overall wear of the abrasive layer and the wear of the outer peripheral edge are large, while in the case of the product of the present invention, (a) of the figure. As shown in (1), although the outer peripheral edge and the periphery of the through hole are worn, the amount of wear is small as a whole.

[0035]

According to the present invention, the following effects can be obtained.

(1) By providing openings at a plurality of locations penetrating the outer peripheral edge of the base metal and the abrasive material layer, chips can be discharged through the openings, and a grinding fluid can be supplied. Discharge performance and supply of grinding fluid can be improved.Especially, by inclining the inner wall of the opening to either the rear side or the front side in the grinding wheel rotation direction, the discharge performance of chips and the supply of grinding fluid can be improved. Either one can be focused on.

(2) By providing a plurality of openings at positions on non-concentric circles, the wear shape of the abrasive layer can be kept flat, and the discharge of cutting chips and the supply of the grinding fluid are made uniform. be able to.

[Brief description of the drawings]

FIG. 1 is a front view of a cup-type rotary grindstone according to an embodiment of the present invention.

FIG. 2 is a rear view of the rotary grindstone of FIG. 1;

3A is a sectional view taken along line AA of FIG. 1, and FIG. 3B is a sectional view taken along line BB of FIG.

FIG. 4 is a partial sectional view at the time of grinding with the rotary grindstone of FIG. 1;

FIG. 5 is a partial cross-sectional view at the time of grinding with a rotary grindstone of another embodiment.

FIG. 6 is a plan view showing another example of the arrangement of the abrasive layer and the openings.

FIG. 7 is a graph showing the results of a grinding experiment.

FIG. 8 is a diagram showing a state of wear of the abrasive material layer after grinding.

[Explanation of symbols]

 Reference Signs List 10 rotating whetstone 11 base metal 11a outer peripheral edge 11b mounting hole 12 abrasive material layer 13, 13a, 13b through hole θ rake angle

Continued on front page F-term (reference) 3C063 AA02 AB02 AB05 BA21 BA22 BB01 BB03 BB04 BG01 BG03 BG04 BH02 BH30 EE15 EE16 FF18 FF20

Claims (2)

[Claims] In a cup-type rotary grindstone in which an abrasive layer is continuously or intermittently attached along an outer edge of a cup-shaped base, an opening penetrating the outer edge of the base and the abrasive layer is continuously formed. Provided at a plurality of locations in the circumferential direction of the abrasive layer that has been permanently attached, or for each of the abrasive layers that are attached intermittently, and the inner wall of this opening is inclined toward the rear or front side in the grinding wheel rotation direction. A cup-type rotary grindstone with through holes, characterized in that 2. The cup-type rotary grindstone with through holes according to claim 1, wherein a plurality of said openings are provided at positions on non-concentric circles.