JPH06278036A - Cup-shaped grinding wheel - Google Patents

Abstract

PURPOSE:To provide a cup-shaped grinding wheel which enables grinding without causing grinding burn even when small in diameter and using its end faces and outer peripheral surface as grinding surfaces. CONSTITUTION:A grinding liquid is readily allowed into a spiral passage 48 and guided to the inner periphery of the passage since the rake angle of the opening of the spiral passage 48 is very small, and the liquid is guided to the end face of a rotating shaft 12 through an axial passage 50 and fed to the inner periphery of a cylindrical grinding wheel main body 14. Therefore, even in the case of a cup-shaped grinding wheel 10 which is drivingly rotated at high speed because of its small diameter with the rotating shaft 12 fitted into the inner peripheral hole of the grinding wheel main body 14, the grinding liquid can be fed to a grinding portion in a sufficient amount to prevent grinding burn, grinding cracking, roughening of a surface to be ground, and abnormal abrasion, etc., and to enable grinding at high efficiency and high performance using simple constitution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cup-shaped grindstone provided with a cylindrical grindstone body, and more particularly to a technique for simply and efficiently introducing a grinding fluid into the inner peripheral space thereof.

[0002]

2. Description of the Related Art A cup-shaped grindstone, a ring-shaped grindstone, a flat-shaped grindstone, and the like are provided with an annular outer peripheral wall, and the end surface of the outer peripheral wall, that is, the grinding surface is brought into sliding contact with the work surface, thereby grinding the work surface. There is known a cup-shaped grindstone of the type. When performing wet surface grinding using such a cup-shaped grindstone, usually, a grinding liquid supply pipe for discharging the grinding liquid toward the vicinity of the grinding portion between the grindstone and the work material is provided. , The grinding liquid is supplied from the pipe to the grinding surface, but since the work surface of the work material and the grinding surface of the cup-shaped grindstone are brought into surface contact, when such grindstone is used, The grinding fluid supplied from is not sufficiently supplied to the grinding surface. For this reason, when trying to maintain the grinding efficiency, grinding burn, grinding cracks, etc. occur, and the effect of the grinding liquid is insufficient, and the grinding quality of the work material cannot be sufficiently obtained.

On the other hand, a plurality of grinding fluid introduction holes are formed through the outer peripheral wall of the cup-shaped grindstone body, and the grinding fluid is discharged from the nozzle toward the grinding fluid introduction holes to form a cup-shaped grinding stone. It has been proposed to supply the grinding fluid directly into the body of the grindstone. For example, Japanese Patent Laid-Open No. 4-576
That is what is described in Japanese Patent Publication No. 77. According to such a cup-shaped grindstone, the grinding fluid introduced into the inside of the cup-shaped grindstone main body can be sufficiently supplied to the sliding contact surface between the grindstone and the work material by the centrifugal force accompanying the rotation of the grindstone. In addition, compared to the case of using a device that supplies grinding liquid into the rotary shaft that supports the cup-shaped grindstone body, a complicated connection device for connecting the grinding liquid supply pipe and the rotary shaft supply hole is not required. Therefore, there is an advantage that the grinding machine is simply configured and is inexpensive.

[0004]

However, for example 20 to 30 mm, such as used in grinding centers.
A relatively small diameter cup-shaped grindstone with an outer diameter of about φ is driven at a high rotation speed of, for example, about 6000 to 8000 rpm while performing step processing such as cutting with an end mill, pocket processing, groove processing, etc. Used. Therefore, in addition to the end surface of the cup-shaped grindstone body, the outer peripheral surface is also used as a grinding surface.Therefore, bring the nozzle that discharges the grinding liquid close to the grinding-fluid introduction hole that opens on the outer peripheral surface of the cup-shaped grindstone body. It is difficult to form the grinding fluid introduction hole itself because it is necessary to fit the rotary shaft into the inner peripheral hole of the grinding wheel body in order to maintain the strength of the cup-shaped grindstone body with a small diameter and thin wall. There was a drawback that the occurrence of burning was unavoidable.

The present invention has been made in view of the above circumstances, and an object thereof is to generate grinding burn even when the diameter is small and the end surface and the outer peripheral surface can also be used as grinding surfaces. It is to provide a cup-shaped grindstone that can be ground without grinding.

[0006]

The gist of the present invention to achieve such an object is to provide a cylindrical grindstone main body and a rotary shaft having the grindstone main body fitted to a tip end thereof, A cup-shaped grindstone of a type in which a grinding liquid is supplied from the inner peripheral side of the grindstone main body at the time of grinding, and (a) is formed on the rotary shaft and is opened on the outer peripheral surface of the rotary shaft and Of the spiral passage toward the inner peripheral side in the direction opposite to the rotation direction of (b), the inner peripheral side end portion of the spiral passage formed in the rotating shaft, and the tip surface of the rotating shaft. And an axial passage communicating between them.

[0007]

According to this structure, when the cup-shaped grindstone is driven to rotate and the grinding liquid is sprayed from the predetermined nozzle toward the outer peripheral surface of the rotating shaft during the grinding process, the grinding liquid is supplied to the outer peripheral surface of the rotating shaft. It is received in the spiral passage open to the surface, guided to the inner peripheral side, further guided to the tip end surface of the rotary shaft by the axial passage, and supplied to the inner peripheral side of the cylindrical grindstone body.

[0008]

As a result, since the rotary shaft is fitted in the inner peripheral hole of the grindstone body and the outer peripheral surface thereof is also used as the grinding surface, it is difficult to form the grinding fluid introduction hole penetrating the outer peripheral wall. Even with the cup-shaped grindstone, the grinding liquid can be sufficiently supplied to the inner peripheral side of the grindstone body by the simple structure of providing the spiral passage and the axial passage on the rotating shaft,
Grinding is possible without causing grinding burn.

The opening of the spiral passage has a smaller rake angle than that of the straight passage, and the spiral passage has a spiral shape as a whole, so that the grinding fluid can be easily received and the spiral fluid is swirled. A large amount of grinding liquid can be supplied into the main body of the grindstone due to the pumping effect of the shape.

[0010] Here, preferably, the spiral passage is formed obliquely so as to be directed toward the tip end surface side of the rotating shaft toward the inner peripheral side. As a result, the flow resistance of the grinding fluid toward the tip surface of the rotary shaft is reduced, and the grinding fluid is more easily supplied to the inner peripheral side of the grindstone body.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a cross section of an essential part of an end mill type cup-shaped grindstone 10 used for step processing, pocket processing, groove processing and the like. The cup-shaped grindstone 10 is a relatively small-diameter grinding tool having an outer diameter of, for example, 20 to 30 mmφ, and is provided, for example, in a grinding center which is a grinding machine capable of automatically replacing various kinds of grinding tools. A base end portion (not shown) of the rotary shaft 12 (upper part in FIG. 1) is connected to a drive shaft to be rotationally driven. The arrow in FIG. 2 indicates the rotation direction of the cup-shaped grindstone 10.

In FIG. 1, a cup-shaped grindstone 10 is composed of a metallic rotary shaft 12 and a cylindrical grindstone main body 14 fitted to the tip of the rotary shaft 12. The grindstone body 14 is made of super abrasive grains such as CBN or diamond bonded by a binder such as a synthetic resin, an inorganic material, or a metal, and is projected from the tip surface of the rotary shaft 12 by a predetermined dimension P. For example, it is fixed to the outer peripheral surface of the rotary shaft 12 with an adhesive.

The rotary shaft 12 has a shaft body 16, an annular member 18 having the same outer diameter as that of the shaft body 16 and fitted at its tip, and the annular member 18 is fastened to the shaft body 16. For this reason, it is formed into a columnar shape by being configured with a bolt member 20 screwed into a female screw hole 19 formed in the shaft body 16. As shown in FIGS. 2 and 3, a frusto-conical surface composed of a small-diameter tip surface 22 and a taper surface 24 on the outer peripheral side thereof is formed at the tip portion of the shaft body 16, and the taper surface 24 is formed on the tapered surface 24. The four spiral blades 26 are integrally formed so as to be continuous along the spiral that extends in the rotation direction of the rotary shaft 12 from the inner peripheral side toward the outer peripheral side. The spiral blade 26 is provided between the concentric circle A having a diameter larger than that of the small-diameter tip surface 22 and the outer peripheral surface of the shaft body 16, and the inclination angle with respect to the circumferential direction, that is, the rake angle, decreases toward the outer peripheral side. Is formed.

The spiral blades 26 are formed so that their heights in the axial direction are substantially the same as each other.
The inner peripheral side portion between the concentric circle B having a larger diameter than that and the concentric circle B is formed higher than the outer peripheral side portion of the concentric circle B, and the stepped surface 28 between the inner peripheral side portion and the outer peripheral side portion is formed. The centering between the shaft body 16 and the annular member 18 is thereby performed.

As shown in FIG. 4, the annular member 18 has an outer peripheral surface having the same diameter as the shaft body 16 and an inner peripheral surface having the same diameter as the concentric circle A and fitted with the stepped surface 28. A first annular member having a shape parallel to the tapered surface 24 and substantially in contact with a portion of the spiral blade 26 on the outer peripheral side of the concentric circle B.
The taper surface 30 and the second taper surface 32 having a taper angle smaller than that of the first taper surface 30 and formed on the side opposite to the first taper surface 30 are provided.

As shown in FIG. 5, the bolt member 20 includes a bolt shaft portion 34 formed with a male screw, and a taper shaft portion 36 continuous with the bolt shaft portion 34 and parallel to the second tapered surface 32. The shaft body 1 is connected to the taper shaft portion 36 and
6 and a disk-shaped head portion 38 having the same diameter. Head 38
Has eight through holes 4 located at equal intervals in the circumferential direction.
0 and a stepped surface 42 that is fitted with the second tapered surface 32 of the annular member 18 are formed.

The rotating shaft 12 is the shaft body 16 and the annular member 1.
8. Since it is assembled from the bolt member 20, the spiral passage 48 formed by the spiral blade 26, the tapered surface 24, and the first tapered surface 30 in the rotating shaft 12, and the inner circumference of the annular member 18. Surface and second tapered surface 32, through hole 4
And an axial passage 50 formed by 0. The spiral passage 48 has a spiral shape that opens toward the outer peripheral surface of the shaft body 16 and heads toward the inner peripheral side in a direction opposite to the rotation direction of the shaft main body 16, and the rake angle increases toward the outer peripheral side. Is formed so as to be smaller and closer to the inner circumferential side, and is closer to the tip end surface of the rotating shaft 12. Also,
The axial passage 50 connects the inner peripheral end of the spiral passage 48 and the tip end surface of the rotary shaft 12.

The cup-shaped grindstone 10 configured as described above
The surface of the rotary shaft 12 is ground by being brought into contact with a work material (not shown) while the base end portion of the rotary shaft 12 is connected and rotated by a chuck device (not shown). In this state, the grinding fluid discharge pipe 52 is arranged near the cup-shaped grindstone 10 so that the grinding fluid discharged from the grinding fluid discharge tube 52 is discharged in a direction substantially matching the center line of the opening of the spiral passage 48. The grinding fluid discharged from the grinding fluid discharge pipe 52 is positively introduced from the four openings of the spiral passage 48.

In this embodiment, since the rake angle of the opening of the spiral passage 48 is extremely small, the spiral passage 48 is formed.
The grinding fluid introduced into the opening of the spiral passage 48 is easily received in the spiral passage 48 and guided to the inner circumference thereof in accordance with the acting force toward the inner peripheral side generated due to the spiral shape of the spiral passage 48. Then, it is guided to the tip surface of the rotary shaft 12 by the axial passage 50 and supplied to the inner peripheral side of the cylindrical grindstone body 14.

Therefore, even if the cup-shaped grindstone 10 is of a type in which it is driven to rotate at a high speed due to its small diameter and the rotary shaft 12 is fitted into the inner peripheral hole of the grindstone main body 14, the rotary shaft 12 has a spiral shape. With the simple structure of providing the passage 48 and the axial passage 50, the grinding fluid can be sufficiently supplied into the grindstone body 14 having a relatively small diameter. Therefore,
Even if the grinding fluid introduction hole cannot be provided through the outer peripheral wall of the grindstone main body 14, the grinding fluid can be sufficiently supplied to the grinding portion, resulting in grinding burn, grinding cracks, roughened surface to be ground, and abnormal wear. And the like can be suitably prevented, and high efficiency and high performance grinding can be performed with a simple structure.

Moreover, since the vortex passage 48 has a small rake angle θ and is vortex-shaped, the pumping effect of the vortex shape allows the grinding fluid to be easily received, and a large amount of grinding fluid can be stored in the grindstone body 14. Can be supplied to.

Further, since the spiral passage 48 of this embodiment is formed so as to be inclined toward the tip end surface side of the rotary shaft 12 as it goes toward the inner peripheral side, the grinding liquid can be more easily fed. There is an advantage that it can be supplied to the tip surface of.

Although one embodiment of the present invention has been described above with reference to the drawings, the present invention can be applied to other modes.

For example, although the grindstone body 14 of the above-described embodiment has a cylindrical shape, it is provided with an annular outer peripheral wall such as a ring shape or a flat shape, and the end surface of the outer peripheral wall is brought into sliding contact with the work plane. Any type of grindstone that grinds the work surface may be used.

Further, although the grindstone body 14 of the above-mentioned embodiment is composed of the superabrasive grindstone, the grindstone may be composed of silicon carbide abrasive grains or fused alumina abrasive grains.

Further, in the above-mentioned embodiment, the four spiral blades 2 are used.
Although 4 spiral passages 48 were formed by 6,
Alternatively, three or five or more spiral passages 48 may be formed.

The above description is merely an embodiment of the present invention, and the present invention can be variously modified without departing from the gist thereof.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main part of a cup-shaped grindstone according to an embodiment of the present invention.

FIG. 2 is a diagram showing a tip end surface of a rotary shaft of the embodiment of FIG.

FIG. 3 is a perspective view showing a tip end portion of a rotary shaft of the embodiment of FIG.

FIG. 4 is a perspective view showing an annular member of the embodiment of FIG.

5 is a perspective view showing a bolt member of the embodiment of FIG. 1. FIG.

[Explanation of symbols]

 10: cup-shaped grindstone 12: rotating shaft 14: grindstone main body 48: spiral passage 50: axial passage

Claims (2)

[Claims] 1. A cup having a cylindrical grindstone body and a rotary shaft having the grindstone body fitted to a tip end portion thereof, and a grinding liquid is supplied from an inner peripheral side of the grindstone body during grinding. A circular grindstone, which is formed on the rotary shaft, opens on the outer peripheral surface of the rotary shaft, and turns toward the inner peripheral side in a direction opposite to the rotating direction of the rotary shaft, and the rotary shaft. A cup-shaped grindstone, which is formed inside, and includes an axial passage that communicates between an inner peripheral side end portion of the spiral passage and a tip end surface of the rotating shaft. 2. The swirl-shaped passage becomes closer to an inner peripheral side,
The cup-shaped grindstone according to claim 1, wherein the cup-shaped grindstone is formed obliquely toward the tip end side of the rotary shaft.