JP2001277135A - Base metal for rotating disc grinding wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the weight of a base metal for a rotating disc grinding wheel having an abrasive layer on the outer periphery of the disc-like base metal, for coping with fast rotation of the grinding wheel. SOLUTION: Solid synthetic resin powders and hollow synthetic resin powders are uniformly admixed to obtain the base metal made of synthetic resins and having an apparent specific gravity of 0.54 to 1.05. Thus, the base metal is made more lightweight while maintaining the practical strength of the base metal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base for a rotary disk wheel, and more particularly to a base for a rotary disk wheel using a resin bond as a binder for abrasive grains.

[0002]

2. Description of the Related Art A rotating disk grinder for grinding steel materials, cemented carbides, cermets, ceramics, etc. is basically a disk-shaped base metal having abrasive grains fixed together with a resin bond as an abrasive layer together with a resin bond. Configuration.

[0003] Aluminum alloy is mainly used for the base metal,
Iron or iron-based alloy with high strength and rigidity is mainly used for the base metal of the grindstone used at high speed rotation. The abrasive layer is made of super-abrasive grains such as diamond abrasive grains and CBN abrasive grains, phenol resin, polyimide It is formed by pressure molding a mixture of resin powders such as resin, polyester resin, epoxy resin, etc., and is of two types: a direct attachment type that is joined to the base metal at the same time as molding, and an adhesion type that is joined with an adhesive There is.

[0004] In the field of grinding, in recent years, grinding with a rotating disk grindstone has shifted to a higher peripheral speed for the purpose of higher efficiency and higher precision. Under high-speed grinding, the iron base metal has a large specific gravity, so that there is a problem that a load on a grinding machine is increased due to an increase in speed and an electric power required for rotation of the grinding wheel is increased. In addition, since the weight of the grindstone increases, excessive stress is generated in the grindstone layer by the high-speed rotation of the grindstone, and the grindstone layer may be separated. In addition, when the specific gravity of the base metal is large, the vibration generated at the time of high-speed rotation increases, which also causes the abrasive layer to peel.

[0005] From the above, in the case of a rotating disk grindstone using an iron base, it is considered that the peripheral speed of the grindstone is limited to 200 m / sec. Therefore, it is conceivable to use a base metal made of aluminum, an aluminum alloy, or a synthetic resin having a small specific gravity, instead of an iron base metal having a large specific gravity and being insecure in bonding strength between the base metal and the abrasive material layer. However, the aluminum alloy base metal has a specific gravity of about 2.7 to 3.0, and the resin base metal has a specific gravity of about 1.7 to 2.1. Although it can be said that there are few problems caused by centrifugal force, the specific strength (tensile strength / specific gravity) of these materials is 25 to 30% lower than that of iron base metal. Not expected (see Table 1). An ideal base metal as a substitute for an iron base metal is a base metal made of a material having low specific gravity and high specific strength.

[0006]

When a grindstone is used at a high speed, the load on the grinding machine can be reduced by reducing the weight of the base of the grindstone. In addition, the vibration at the time of high-speed rotation, which is considered to have a great effect on the speeding up and the separation of the abrasive grain layer, has an important factor in the dynamic balance of the grinding wheel. If there is an eccentric imbalance in the weight distribution around the rotation axis of the whetstone, when the whetstone is actually attached to the grinding machine and rotated, this weight distribution unbalance,
That is, an uneven centrifugal force in the circumferential direction caused by the displacement of the center of gravity with respect to the rotation center of the grindstone acts, and the rotating grindstone vibrates.

[0007] In the production process of the grindstone, although it is produced so that the weight distribution around the rotation axis becomes uniform, it is inevitable that a slight imbalance remains due to inevitable production errors and the like. If such an imbalance exists, its effect is reduced as the overall weight of the grindstone is reduced. In a rotating disk whetstone having an abrasive layer on the outer periphery of the base metal,
The ratio of the base metal to the total weight is large, and the smaller the weight of the base metal, the smaller the effect of the centrifugal force, which is advantageous in terms of dynamic balance and facilitates the manufacture of a grindstone.

The problem to be solved by the present invention is to further reduce the weight of the base metal in order to cope with the high-speed rotation of the grindstone.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a base for a rotating disk grindstone having an abrasive layer on the outer periphery of a disk-shaped base, comprising a solid synthetic resin particle and a hollow synthetic resin particle. It is characterized in that the body is uniformly mixed to give a synthetic resin base metal having an apparent specific gravity of 0.54 to 1.05.

[0010] By uniformly mixing solid synthetic resin particles and hollow synthetic resin particles, it is possible to further reduce the weight of the base while maintaining the practical strength of the synthetic resin base. it can. The specific gravity of the conventional synthetic resin base metal is 1.7
Since it is about 2.1, the weight is reduced by about 1/2 compared to this.

Here, the hollow synthetic resin particles (hereinafter, referred to as “the synthetic resin particles”)
As the hollow particles, it is desirable to use particles having a particle size of 5 to 130 μm and an apparent specific gravity of 0.1 to 0.8.
Various types of hollow particles are commercially available,
In view of the suitability of the rotating disk grindstone as a base metal material, the particle size and specific gravity of the granules are important requirements. Regarding the particle size of the hollow particles, solid synthetic resin particles (hereinafter referred to as solid particles)
In order to obtain a uniform mixture with the metal powder and not to impair the strength as a base metal, the particle size is 5 to 130 which is equivalent to the particle size of the solid particles.
It is preferable that the particle size is μm. If the particle size is less than 5 μm, the pores inside the hollow particles are small and the porosity of the mixture is low, so that the effect of weight reduction cannot be expected. If the particle size exceeds 130 μm, the difference in particle size from the solid particles becomes large, making it difficult to obtain a uniform mixture, and the pores inside the hollow particles become large, and the strength of the base metal decreases.

Regarding the apparent specific gravity of the hollow particles, at least the apparent specific gravity is preferably 0.8 or less in order to achieve a weight reduction of about 50% more than that of the conventional synthetic resin base metal. . If the apparent specific gravity of the hollow particles is more than 0.8, the pores inside the hollow particles are relatively small with respect to the particle size, and the effect of weight reduction cannot be expected. If the apparent specific gravity is less than 0.1, the pores inside the hollow particles are relatively large with respect to the particle diameter, and the strength of the base metal is reduced (see Table 1).

The mixing ratio of the solid particles and the hollow particles depends on the particle size and apparent specific gravity of the hollow particles, but is 30 to 80% by volume, and 20 to 70% by volume. % Is desirable. If the mixing ratio of the hollow particles is less than 20% by volume, the weight of the base metal becomes insufficient, and if it is more than 70% by volume, the strength of the base metal decreases. Practical application in the speed range becomes difficult.

As the solid particles, synthetic resins such as a phenol resin, an epoxy resin, and a polyester resin which are conventionally used for a resin base can be used. Among them, phenol resins and epoxy resins are preferable in that high strength can be maintained even when the hollow particles are mixed.

The method of manufacturing the base metal itself is basically the same as the conventional method of manufacturing a resin base metal. A mixture of solid particles and hollow particles is pressed and sintered to form a base metal. . Mixing of solid particles and hollow particles by using a high-speed blade stirrer
It can be mixed uniformly.

The bonding strength when the abrasive layer is bonded to the base metal of the present invention can maintain the same bonding strength as that of the conventional resin base metal. Even if the internal mechanism of the hollow particles is exposed on the joint surface, the pores disappear because the resin bond (resin) used for fixing the abrasive grains flows into the pores and hardens when forming the abrasive layer. Along with
The bonding strength is higher than the conventional resin base metal.

[0017]

Embodiments of the present invention will be described below based on test examples. As shown in FIG.
m, a rotating disk grindstone in which an annular diamond abrasive layer 2 having an outer diameter of 200 mm and an inner diameter of 194 mm was joined to the outer periphery of a base metal 1 having an outer diameter of 194 mm and an inner diameter of 50.8 mm. And it was manufactured by changing the material composition. The solid granules used for the base of the grinding wheels of Invention products 1 to 6 have an average particle size of 15
μm phenolic resin, and the hollow particles have an average particle size of 90
It is a phenol resin having an μm and an apparent specific gravity of 0.23. Comparative products 1 and 2 are whetstones in which the mixing ratio of solid particles and hollow particles is out of the range of the present invention. Conventional product 1 is an iron alloy base metal, and conventional product 2 is an aluminum alloy base. Gold and Conventional Product 3 are grindstones made of resin base metal.

Table 1 shows the characteristics of each grinding wheel. As can be seen from Table 1, the grindstone according to the present invention (Invention products 1 to 6) achieves weight reduction while maintaining practical strength.

[Table 1]

[0019]

According to the present invention, the base of a rotating disk grindstone is mixed uniformly with solid synthetic resin granules and hollow synthetic resin granules to form a synthetic resin base having an apparent specific gravity of 0.54 to 1.05. By doing so, it is possible to further reduce the weight of the conventional synthetic resin base metal while maintaining the practical strength of the synthetic resin base metal.

[Brief description of the drawings]

FIG. 1 is a view showing a superabrasive wheel subjected to a test, wherein (a) is a front view and (b) is a longitudinal sectional view.

[Explanation of symbols]

 1 base metal 2 abrasive layer

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hiroaki Takao 210 No. Takeno, Tanushimaru-cho, Ukiha-gun, Fukuoka Prefecture Noritake Diamond Co., Ltd. F-term (reference) 3C063 AA02 AB03 BA02 BC03 BG01 FF23 FF30

Claims (3)

[Claims] 1. A base for a rotating disk whetstone having an abrasive layer on the outer periphery of a disk-shaped base, wherein solid synthetic resin particles and hollow synthetic resin particles are uniformly mixed, Multiplying specific gravity 0.54
A base for a rotating disk grindstone, wherein the base is made of a synthetic resin base of 1.05 to 1.05. 2. The method according to claim 1, wherein the hollow synthetic resin particles have a particle size of 5-1.
2. The base for a rotating disk grinding wheel according to claim 1, wherein the base is a granule having an apparent specific gravity of 0.1 to 0.8 at 30 [mu] m. 3. The mixing ratio of the solid synthetic resin particles and the hollow synthetic resin particles is from 30 to 8 solid synthetic resin particles.
3. The base for a rotating disk grindstone according to claim 1, wherein the volume is 0% by volume and 20 to 70% by volume of hollow synthetic resin particles.