JP3521675B2 - Polishing tool and polishing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has, for example, a pin shape like a die-cast pin portion in a casting die of an engine cylinder block, and secures a sufficient space around it for polishing. The present invention relates to a polishing tool and a polishing method for polishing a portion that cannot be processed.

[0002]

2. Description of the Related Art For example, a die for aluminum die casting for manufacturing a cylinder block for an automobile engine is
The cylinder block is provided with a cast pin for forming a pilot hole for a head bolt.

This cast pin has a temperature of about 650 ° C. when cast.
Since the aluminum alloy is heated in contact with the aluminum alloy, the alloy is deposited and deposited on the pin surface. If such aluminum alloy deposits continue to be produced while adhering to the pin surface, the function of the draft angle formed on the die-cast pin will not work, causing sudden failures such as pin breakage. It is necessary to remove such deposits.

[0004]

In order to remove the aluminum alloy adhering to the surface of such a casting pin, it is conceivable to use a small grindstone with a shaft which is generally used as a mold polishing tool. However, as a matter of course, the tendency toward weight reduction of automobile parts extends to the cylinder block for engines, and the wall thickness of the rough material of the cylinder block tends to be thin. Since it is not possible to secure the space of around the pin, there is a problem that the life of the cast pin is shortened because adhered substances remain or the pin is excessively polished.
Establishing a technology to efficiently remove such deposits without damaging the pin body reduces the downtime of casting equipment caused by deposits on the surface of the pin, such as pin breakage. However, it has been a problem to improve the production efficiency.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems in the casting of cylinder blocks for engines, and has a pin shape like the above-mentioned casting pin of the casting die, An object of the present invention is to provide a polishing tool and a polishing method capable of efficiently polishing a place where a sufficient space for polishing cannot be secured around the periphery.

[0006]

A polishing tool according to claim 1 of the present invention comprises a compression coil spring and a holder portion for holding one end side of the compression coil spring. Boron nitride is provided inside the coil spring. In the polishing tool according to claim 2 as an embodiment of the polishing tool according to claim 1, the polishing material consisting of is attached to the inside of the coil spring, and the axis of the coil spring is substantially The polishing tool according to claim 3 has a configuration including parallel spiral cylindrical surfaces, and is used for polishing a die-cast pin provided in a die for aluminum die casting. The structure of such a polishing tool is used as a means for solving the above-mentioned conventional problems.

In the polishing method according to claim 4 of the present invention, the above-mentioned polishing tool is attached to a power drive unit to perform polishing, and in the polishing method according to claim 5 of the present invention, the above-mentioned polishing tool is When attached to a power drive unit and polished, the coil drive coil rotation direction by the power drive unit is set so that the winding direction of the coil spring is set to be opposite to the rewinding direction of the coil spring. The structure of such a structure in the polishing method is used as a means for solving the above-mentioned conventional problems.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The polishing tool according to the present invention comprises a compression coil spring and an abrasive material attached to the inner surface thereof by electrodeposition. The outer peripheral surface of a pin-shaped object to be polished is a cylindrical portion or a spring. Although the inner surface is polished, boron nitride (sometimes called borazon) can be used as the abrasive used in the polishing tool according to the present invention.

The grain size of the abrasive is selected according to the type, material, shape, size, etc. of the object to be polished.
In the case of the above-mentioned die-cast pin, a relatively fine grain size, for example, 170-360 (170-360 mesh), should be used so that it will not be removed by polishing and surface treatment such as titanium coating. Is desirable. Further, when the particles of the abrasive are larger than 170 mesh, the particles are likely to peel off.

As a means for adhering such an abrasive made of boron nitride to the inside of the coil spring, a method by electrodeposition of a metal such as nickel can be adopted,
The bond strength can be improved.

For example, when applying an abrasive to a base member having a cylindrical portion as shown in FIGS. 2 and 3, it is necessary to apply electrodeposition to the inner surface of the cylindrical portion of the base member. However, in the present invention, the compression coil spring is used without using the base member having such a shape. , The inside can be electrodeposited. In addition, the polishing condition can be observed from between the coils, polishing debris can be easily discharged, and the compression coil spring elastically deforms appropriately according to the shape of the object to be polished. By adjusting, it is possible to finely adjust the degree of contact with the object to be polished according to the work purpose, and there are many advantages that workability is improved.

A holder portion is attached to one end of the compression coil spring to which an abrasive is attached, and the holder is used for polishing a pin-shaped object to be polished. Like the base member, the holder portion is provided with a grip and a handle for attaching to a power driving device such as a grinder.

The wire diameter of the compression coil spring is selected according to the type and material of the object to be polished, the shape, the size, the purpose of polishing, the elasticity of the wire, and the like. In the case of pins, it is approximately 1.2 mm
About 2.4 mm is preferable, and only the aluminum alloy adhering to the pin surface can be efficiently removed by adjusting the elastic coefficient of the spring.

Further, in the electrodeposition process on the compression coil spring, the inner peripheral surface of the spring is ground so that the wire cross section of the spring has a D-shape as shown in FIG. (A spiral cylindrical surface parallel to the axis will be formed on the inner peripheral surface of the), and the contact area with the object to be polished increases and the amount of electrodeposition on the grinding surface increases, and The adherence of the abrasive becomes stronger (claim 2). From this point of view, it is also desirable to use a compression coil spring made of a wire having a rectangular cross section as shown in FIG.

The polishing tool having such a structure is applied to polishing work, for example, by manual work or by being attached to a power driving device such as an electric grinder or an air grinder as described in claim 4.

When a polishing tool using a compression coil spring is attached to a power tool as described above and used,
When the winding direction of the spring coincides with the rotating direction of the power tool, the compression coil spring is rewound and the coil diameter is expanded. Therefore, as described in claim 5,
It is desirable to set the winding direction of the coil spring so that the rotation direction of the coil spring by the power drive device is opposite to the winding direction of the coil spring.

[0017]

The polishing tool according to claim 1 of the present invention comprises:
It consists of a compression coil spring and a holder that holds one end of the spring, and the abrasive material made of boron nitride is attached to the inside of the compression coil spring by electrodeposition. By making sliding contact with the outer peripheral surface of the object to be polished, it forms a pin shape, and even for objects to be polished that do not have a wide space around it,
Its surface can be efficiently polished.For example, by applying it to the die polishing of the die for aluminum die casting of the cylinder block for engines, the aluminum alloy attached to the die-cast pin provided in the die can be used for the pin body. It can be easily removed without damage, extending the service life of the die-cast pin, and preventing equipment stoppages due to troubles caused by deposits on the pin surface, thus greatly increasing production efficiency. It brings about an extremely excellent effect that it can be improved. Further, since the compression coil spring is used as a base for adhering the abrasive material, the inner surface of the compression coil spring can be electrodeposited relatively easily, and a polishing tool having excellent bonding strength can be obtained. In addition, the polishing condition can be observed from the gap of the coil, polishing debris can be easily discharged from the gap, and the elastic coefficient of the spring can be adjusted to slightly change the sliding contact strength to the work piece according to the work purpose. It is possible to improve the workability of polishing, which is an extremely excellent effect.

As an embodiment of the polishing tool according to the present invention, in the polishing tool according to claim 2, since the spiral spring has a cylindrical surface substantially parallel to the axis inside the coil spring, the amount of electrodeposition is increased. As a result, the bonding strength of the abrasive is improved, and the contact area with the object to be polished is increased, so that the polishing efficiency can be improved, which is an excellent effect.

As an embodiment of the polishing tool according to the present invention, in the polishing tool according to claim 3, since the casting pin provided in the die for aluminum die casting is used for polishing, the polishing tool concerned. You can maximize the benefits of.

In the polishing method according to the fourth aspect of the present invention, since the polishing tool according to the present invention is mounted on a power driving device such as an electric grinder or an air grinder, it is highly efficient without any labor. Polishing becomes possible, and in the polishing method according to the fifth aspect of the present invention, when the polishing tool according to the present invention is mounted on the drive device as described above and polishing is performed, the winding direction of the spring is
Since the rotation direction of the spring by the drive unit and the rewinding direction of the coil spring are set to be opposite to each other, the compression coil spring will not be rewound by the rotational force of the drive unit, and the smoothness will be smooth. The excellent effect that a polishing operation can be performed is brought about.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings.

1 (a) to 1 (c) show, as an embodiment of a polishing tool according to the present invention, a casting pin (length: 70 mm, diameter: included in a die for aluminum die casting of a cylinder block for an engine). Fig. 2 shows the structure of a polishing tool designed to remove aluminum solidified by adhering to the surface and solidifying by polishing 7.0 mm, draft angle: 1 °).

That is, as shown in FIGS. 1A and 1B, the polishing tool 1 is mainly composed of a holder portion 2 and a compression coil spring 3 whose one end side is held by the holder portion 2. There is.

The holder part 2 is formed by integrally turning a holder body 2a and a handle 2b for attaching the polishing tool 1 to a chuck of a power driving device such as an electric grinder or an air grinder. Body 2
The a is provided with a fitting hole 2c for receiving the compression coil spring 3 and a screw hole 3d screwed into a screw 4 for fixing the spring 3 fitted in the fitting hole 2c.

On the other hand, in this embodiment, the compression coil spring 3 is made by winding a wire of 1.5 mm in the left direction around the inner diameter of the coil of 8.0 mm, and has a length of about 80 mm. Then, as shown in an enlarged view in FIG. 1C, 320 mesh boron nitride 5 as an abrasive is attached to the inside by electrodeposition of nickel. The winding direction of the compression coil spring 3 takes into consideration that the rotation direction of the air grinder for mounting the polishing tool 1 is right rotation.

The compression coil spring 3 which has been subjected to the electrodeposition process is fixed by tightening the screw 4 so that one end thereof is fitted in the fitting hole 2c of the holder portion 2.

The polishing tool 1 thus completed is attached to an air grinder (not shown) and used to polish the die-cast pin of the die for aluminum die casting.

At this time, the compression coil spring 3 of the polishing tool 1 can easily reach the base of the casting pin if the gap of several mm exists around the casting pin of the die, and the gap of the coil is reduced. Polishing chips are discharged from the gap, the polishing condition can be observed from the gap, and since it elastically deforms appropriately following the pin shape, the alloy adhered to the pin surface with good workability without overpolishing. It can be easily removed without damaging the surface treatment of the die-cast pin such as titanium coating.

Further, since the rotating direction of the air grinder and the rewinding direction of the compression coil spring 3 are opposite to each other, the spring 3 is not rewound during the polishing, and the polishing work for a long time can be performed. It will be possible.

[Brief description of drawings]

FIG. 1A is a front view showing an embodiment of a polishing tool according to the present invention. (B) It is a longitudinal cross-sectional view of the polishing tool shown in FIG. (C) It is a principal part expanded sectional view of the polishing tool shown to Fig.1 (a).

FIG. 2 is a reference view showing another structural example of the polishing tool.

FIG. 3 is a reference view showing still another structural example of the polishing tool.

FIG. 4 is an enlarged sectional view of a compression coil spring portion showing another embodiment of the polishing tool according to the present invention.

FIG. 5 is an enlarged partial sectional view of a compression coil spring portion showing still another embodiment of the polishing tool according to the present invention.

[Explanation of symbols]

1 polishing tool 2 Holder part 3 compression coil spring 5 Boron nitride (abrasive)

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Claims (5)

(57) [Claims] 1. A compression coil spring and a holder portion for holding one end side of the compression coil spring, wherein an abrasive made of boron nitride is attached to the inside of the coil spring by electrodeposition. Polishing tool to do. 2. The polishing tool according to claim 1, further comprising a spiral cylindrical surface inside the coil spring, the spiral cylindrical surface being substantially parallel to the axis of the coil spring. 3. The polishing tool according to claim 1, which is used for polishing a die-cast pin provided in a die for aluminum die casting. 4. A polishing method comprising: mounting the polishing tool according to any one of claims 1 to 3 on a power drive device for polishing. 5. When the polishing tool according to any one of claims 1 to 4 is attached to a power drive unit for polishing,
A polishing method, wherein the winding direction of the coil spring is set so that the rotation direction of the coil spring by the power drive device is opposite to the winding direction of the coil spring.