JPH0451979Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of the substrate of a diamond cutting wheel used for cutting stones, concrete, refractories, iron, etc.

[Conventional technology]

The most typical structure of diamond cutting wheels, which are widely used to cut various hard materials, is one in which a diamond layer is baked onto the outer periphery of a thin disc-shaped substrate. When such a diamond cutting grindstone performs a cutting operation, a large load is applied to the diamond layer and the substrate due to the reaction force received from the material to be cut.

In this way, deformation and destruction of the diamond layer and the substrate are inevitable, especially since compressive stresses continue to act during the cutting operation. As a countermeasure against this problem, various structures have been adopted in the past to strengthen the substrate and prevent it from deforming or breaking.

On the other hand, as a conventionally most commonly used diamond cutting grindstone, there is one shown in FIG. 3, for example. This is made by integrating a plurality of diamond chips 2 on the periphery of a substrate 1 formed into a disk shape from a metal plate. and,
A rotating shaft hole 3 is provided in the substrate 1, and a plurality of slits 4 are cut out radially around the periphery, and a diamond chip 2 is fixed by baking except for the slit 4 portions.

[Problem that the invention attempts to solve]

However, most of the stress in the radial and circumferential directions applied from the material to be cut during operation is concentrated in the slit 4 cut out in the periphery of the substrate 1.
Among the slits 4, the stress distribution force in the circular opening 5 near the center is the largest.

In this way, since stress is concentrated on the slit 4 and the circular opening 5, cracks and fractures are likely to occur in these parts. This causes deformation and destruction of the substrate 1, which increases the frequency of replacement.

In addition, the amount of deformation up to failure is slit 4
Since there are multiple notches on the periphery of the substrate 1, the edges are much larger than the center. and,
During the cutting operation, the substrate 1 rotates at high speed and the resistance received from the material to be cut varies, so the amount of deformation of the substrate 1 becomes even larger. In this situation,
There is also a problem that the substrate 1 shakes around its axis, and the substrate 1 vibrates so much that it becomes impossible to work or the substrate 1 itself suffers from fatigue failure.

Therefore, an object of the present invention is to improve the reinforcing structure of the substrate so that the cutting operation can be performed efficiently.

[Means for solving problems]

In order to achieve the above object, the present invention provides a diamond cutting grindstone in which a plurality of radial slits are cut around a disk-shaped substrate and diamond chips are provided on the outer periphery of the substrate. The present invention is characterized in that concave portions surrounding the ends are provided on both sides of the substrate by press working.

〔Example〕

Hereinafter, the features of the present invention will be specifically explained with reference to embodiments shown in the drawings.

FIG. 1 is a front view of a diamond cutting grindstone showing an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the - line arrow in FIG. Note that the reference numbers are the same as those of the conventional example.

As described in the conventional example, the diamond cutting grindstone is composed of a disk-shaped substrate 1 made of a metal plate and diamond chips 2 provided around the disk-shaped substrate 1.

The substrate 1 has a cutting machine (not shown) in its center.
A rotary shaft hole 3 to be mounted on the rotary shaft is provided, and a plurality of slits 4 are cut radially on the circumferential surface.

The diamond chip 2 is inserted into the slit 4 of the substrate 1.
The chips are discontinuous sintered chips arranged in a manner such that the parts are cut out, and are integrated onto the circumferential surface of the substrate 1 by baking, brazing, or other means.

The slits 4 of the substrate 1 are formed in a radial direction that opens around the edges, and a circular opening 5 is continuously cut in the center side to prevent the slits 4 from cracking inward. Around this circular opening 5, recesses 6 are formed on both sides of the substrate 1.

The recess 6 has a substantially arcuate shape concentric with the circular opening 5, and takes a posture in which the center of the arc is located on a diameter from the center of the substrate 1. Further, the recess 6 is manufactured by a commonly used press process. By adopting this method, plastic deformation is caused in the recessed portion, and the recessed portion can be made stronger than the entire substrate. Furthermore, the advantage of this method is that the thickness of the substrate can be strengthened in a thin state.

Further, the recesses 6 may be formed continuously in a well-arc shape as shown in the figure, or may be arranged in a circular arc shape with discontinuous points. Furthermore, when forming on both sides of the substrate 1, if the thickness is sufficient, they can be provided at symmetrical positions on the front and back, and if the thickness is thin, they can be placed offset from each other. Note that it is preferable that the depth of the recess 6 is, for example, about 0.1 mm to approximately half the thickness of the substrate 1. Further, the distance between the slit 4 and the circular opening 5 is also changed as appropriate depending on the thickness of the substrate 1 and the load received during cutting.

Here, when integrating the diamond chip 2 into the substrate 1 which has recesses 6 on both sides in addition to the slits 4, it is extremely important to apply plastic working to the entire substrate 1, and the processing method will be described below. .

First, a mixture of diamond abrasive grains and metal powder as a binder is processed and formed into a desired shape on the outer periphery of the substrate 1. Thereafter, this molded product is placed between molds such as graphite plates and sintered in an atmosphere at a temperature of 600 to 1000°C. Then, during this sintering, the same effect as annealing is given to the substrate 1. That is, if the substrate 1 is sufficiently subjected to plastic working, crystal grains will be prevented from becoming coarser or finer, and the toughness of the substrate 1 will be improved, resulting in improved fatigue strength. In addition, recrystallization progresses rapidly over the entire surface of the substrate 1 during heating, and residual stress caused by pressing and rolling of the substrate material and its directionality are eliminated, and the substrate 1 after sintering is
has excellent toughness and reduced distortion.

In the diamond cutting grindstone manufactured as described above, the external force applied to the substrate 1 is concentrated on the slit 4 portion. That is, stress concentration occurs at the edges of the plurality of slits 4 and circular openings 5 provided around the substrate 1. At this time, since a recess 6 is formed around the circular opening 5, the concentrated stress is dispersed to the recess 6 due to the notch effect.

Therefore, the external force applied during cutting work is
Since the particles are dispersed not only in the slit 4 but also over a wide area, the toughness of the substrate 1 described above is improved and the strength is significantly increased.

Further, since the slits 4 and the recesses 6 are formed only in the peripheral portion of the substrate 1, the flatness of both surfaces of the substrate 1 can be maintained to a certain extent compared to the conventional one. Therefore, even if the substrate 1 rotates at high speed, vibrations due to the influence of surrounding airflow are suppressed, allowing efficient cutting work.

Although discontinuous diamond chips are used in the above embodiments, the same applies if a diamond layer is provided around the entire circumference.

[Effect of idea]

As explained above, in the reinforced structure of the substrate of the diamond cutting grindstone of the present invention, a plurality of slits extending in the radial direction are provided on the circumferential surface of the substrate, and a well-arc-shaped recess that surrounds the base end of the slit is formed. are recessed on both sides of the board. Therefore, the stress received during cutting is dispersed not only by the slits but also by the notch effect in the recesses, so that there is no local concentration of stress and the strength of the substrate is greatly improved. Also,
Since the slits and recesses are provided in a relatively narrow area only at the edges of the substrate, the flatness of the substrate is maintained to a certain extent, allowing efficient work without vibrations caused by high-speed rotation.

[Brief explanation of the drawing]

Fig. 1 is a front view of a diamond cutting grindstone showing an embodiment of the present invention, Fig. 2 is a sectional view taken along the - line arrow in Fig. Figure b is a sectional view taken along the - line arrow in figure a. 1...Substrate, 2...Diamond chip, 3...
...Rotating shaft hole, 4...Slit, 5...Circular opening,
6... Concavity.

Claims (1)

[Scope of utility model registration request] In a diamond cutting grindstone in which a plurality of radial slits are cut around a disk-shaped substrate and diamond chips are provided on the outer periphery of the substrate, a concave portion surrounding the base end of the slit is formed by press working. A reinforced structure for a substrate of a diamond cutting grindstone, characterized in that the substrate is provided on both sides of the substrate.