JP2000042802A - Guide bush and forming of coat on guide bush - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure of a guide bush for forming a hard carbon film with good adhesiveness on the guide bush inner circumferential face, and a forming method of the hard carbon film, capable of forming the hard carbon film with the good adhesiveness and with a uniform film thickness on the opening inner face of the guide bush. SOLUTION: A cemented carbide member 12 is formed on the inner circumferential face of a guide bush 11 equipped with an outer circumferential taper face, a slitting and a screw part, and a hard carbon film 15 is formed on the upper face of the cemented carbide member 12 through an intermediate layer 14, and irregularities are formed on the surface of the hard carbon film 15 so as to copy irregularities of the surface of the cemented carbide member 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a rotary or fixed type guide bush provided on an automatic lathe for rotatably supporting a workpiece, and a coating of the guide bush with an intermediate layer and a hard carbon film. To a method of forming

[0002]

2. Description of the Related Art An inner peripheral surface of a guide bush provided on an automatic lathe column of an automatic lathe to rotatably support a workpiece is
The workpiece always contacts and rotates together, or the workpiece rotates on the inner peripheral surface thereof, and further slides in the axial direction.

A structure in which a superhard member or ceramics is provided on the inner peripheral surface of a guide bush that comes into contact with a workpiece by rotation or sliding has been proposed, for example, in Japanese Patent Laid-Open No. 4-141303. In the guide bush described in this publication, in which a super-hard member or ceramic having excellent wear resistance and heat resistance is provided on the inner peripheral surface, an effect of suppressing a certain amount of wear is recognized.

[0004] However, in the guide bush described in this publication, in the case of heavy cutting in which the amount of cutting is large and the machining speed is large with an automatic lathe, a super hard material or ceramic is processed due to a large friction coefficient and a low thermal conductivity. Scratches are generated on the object, and the diameter of the gap between the guide bush and the workpiece in the diameter direction is reduced, so that seizure occurs.

Therefore, it has been proposed to cover the upper surface of the super hard member provided on the inner peripheral surface of the guide bush with a hard carbon film to suppress the abrasion of the inner peripheral surface. This hard carbon film is a black film and has properties very similar to diamond.
That is, the hard carbon film has excellent characteristics such as high mechanical hardness, low coefficient of friction, good electrical insulation, high thermal conductivity, and high corrosion resistance.

For this reason, it has been proposed and put to practical use to coat decorative articles, medical equipment, magnetic heads, tools and the like with a hard carbon film. This hard carbon film is a hydrogenated amorphous carbon film, and has properties similar to diamond as described above, and is therefore called a diamond-like carbon film (DLC) or i-type carbon film.
Also called a carbon film.

[Prior art method of forming hard carbon film on guide bush: FIG. 14] A conventional method of forming a hard carbon film on guide bush using plasma chemical vapor deposition is described with reference to FIG. explain. FIG. 14 is a cross-sectional view showing a method of forming a hard carbon film according to the prior art.

As shown in FIG. 14, a guide bush 11 for forming a hard carbon film is arranged in a vacuum chamber 61 having a gas inlet 63 and an exhaust port 65. The guide bush 11 performs quenching and tempering after forming an outer shape and an inner shape using alloy tool steel (SKS). A super hard member is provided on the inner peripheral surface of the guide bush 11.

A DC voltage is applied to the guide bush 11 from a DC power supply 73. Further, a DC voltage is applied from an anode power supply 75 to an anode 79 disposed to face the guide bush 11, and an AC voltage is applied to the filament 81 from a filament power supply 77.

Then, after the inside of the vacuum chamber 61 is evacuated from the exhaust port 65 by exhaust means (not shown), a gas containing carbon is introduced into the vacuum chamber 61 from the gas inlet port 63, and plasma is generated in the vacuum chamber 61. Generate the guide bush 1
1, a hard carbon film is formed.

In the method of forming a hard carbon film using the apparatus shown in FIG. 14, a plasma generated by a DC voltage applied to the guide bush 11, a filament 81 for applying an AC voltage, and an anode 79 for applying a DC voltage are provided. And the generated plasma.

The plasma in the vicinity of the guide bush 11 or the plasma in the vicinity of the filament 81 and the anode 79 mainly forms the hard carbon film due to the pressure in the vacuum chamber 61 when the hard carbon film is formed. I have.

[0013]

In the method for forming a hard carbon film described with reference to FIG. 14, when the pressure in the vacuum chamber 61 is 3 × 10 ⁻³ torr or more, the area around the guide bush 11 is reduced. The generated plasma is mainly
The gas containing carbon is decomposed to form a hard carbon film.

At this time, a hard carbon film can be formed on the outer peripheral portion of the guide bush 11 with good uniformity.
The hard carbon film formed on the inner surface of the opening of the guide bush 11 has poor adhesion, and further has poor film quality such as hardness.

This is because the same potential is applied to the guide bush 11, the inner surface of the opening is a space where electrodes of the same potential face each other, and the plasma on the inner surface of the opening generates an abnormal discharge called hollow discharge. I do.

The hard carbon film formed by the hollow discharge is a polymer-like film having poor adhesion, and is easily peeled from the inner surface of the opening of the guide bush 11.
Its hardness is also low.

On the other hand, when the pressure inside the vacuum chamber 61 is 3
When it is lower than × 10 ^-3 torr, the guide bush 11
The plasma generated in the vicinity of the filament 81 and the anode 79 mainly contributes to the formation of the hard carbon film from the surrounding plasma.

At this time, a hard carbon film can be formed on the outer peripheral portion of the guide bush 11 with good uniformity.
The hard carbon film formed on the inner surface of the opening of the guide bush 11 cannot have a uniform thickness in the longitudinal direction of the guide bush 11.

Here, the filament 81 and the anode 79
The carbon ions ionized by the plasma generated in the vicinity are pulled by the DC negative potential applied to the guide bush 11 and deposited, thereby forming a hard carbon film on the guide bush 11.

The pressure in the vacuum chamber 61 is 3 × 10 ⁻³ t.
When the pressure is higher than orr, the pressure is 3 × 10 ⁻³ torr when the hard carbon film is formed by chemical vapor deposition.
When it is lower than r, a hard carbon film is formed by physical vapor deposition.

For this purpose, the filament 81 and the anode 7
In the case of forming a hard carbon film in which plasma generated in the vicinity of 9 mainly contributes, the inner surface of the opening of the guide bush 11 extends from the opening end face toward the back of the opening, similarly to the physical vapor deposition method such as the vacuum evaporation method. The thickness of the hard carbon film is reduced. As a result, the hard carbon film formed on the inner surface of the opening of the guide bush 11 cannot have a uniform thickness in the longitudinal direction of the guide bush 11.

Further, it is also required to improve the durability of the hard carbon film formed on the inner peripheral surface to enhance the reliability of the guide bush for long-term use.

[Object of the Invention] An object of the present invention is to solve the above problems, improve the durability of the hard carbon film formed on the inner peripheral surface, and improve the reliability of the guide bush for long-term use. An object of the present invention is to provide a simple guide bush structure and a method for forming a hard carbon film capable of forming a hard carbon film with good adhesion and a uniform film thickness on the inner surface of the opening of the guide bush.

[0024]

Means for Solving the Problems In order to achieve the above object, in the structure of the guide bush of the present invention and the method of forming a coating on the guide bush, the following means are employed.

The guide bush of the present invention has a substantially cylindrical shape having a central opening penetrating in the axial direction.
One end in the longitudinal direction is formed with an outer tapered surface and a slit for giving it elasticity, and the other end is provided with a screw portion for attaching to a column of an automatic lathe. An inner peripheral surface for holding the workpiece is formed around the periphery, and the workpiece inserted into the center opening by being attached to the automatic lathe is cut by the inner peripheral surface holding the workpiece. Is a guide bush in which an intermediate layer is provided on the inner peripheral surface and a hard carbon film is formed on the intermediate layer, and the surface of the hard carbon film is It is characterized by being uneven.

The guide bush of the present invention has a substantially cylindrical shape having a central opening penetrating in the axial direction.
One end in the longitudinal direction is formed with an outer tapered surface and a slit for giving it elasticity, and the other end is provided with a screw portion for attaching to a column of an automatic lathe. An inner peripheral surface for holding the workpiece is formed around the periphery, and the workpiece inserted into the center opening by being attached to the automatic lathe is cut by the inner peripheral surface holding the workpiece. , And slidably held in the axial and axial directions, and provided with a superhard member on its inner peripheral surface.
A guide bush having an intermediate layer provided on the superhard member and a hard carbon film formed on the intermediate layer, wherein the surface of the hard carbon film is uneven.

The guide bush of the present invention has a substantially cylindrical shape having a central opening penetrating in the axial direction.
One end in the longitudinal direction is formed with an outer tapered surface and a slit for giving it elasticity, and the other end is provided with a screw portion for attaching to a column of an automatic lathe. An inner peripheral surface for holding the workpiece is formed around the periphery, and the workpiece inserted into the center opening by being attached to the automatic lathe is cut by the inner peripheral surface holding the workpiece. , And slidably held in the axial and axial directions, and provided with a superhard member on its inner peripheral surface.
A guide bush in which an intermediate layer is provided on the super hard member, and a hard carbon film is formed on the intermediate layer, and the surface of the super hard member is uneven, so as to follow the unevenness of the surface of the super hard member. In addition, the surface of the hard carbon film is uneven.

The guide bush of the present invention has a substantially cylindrical shape with a central opening penetrating in the axial direction.
One end in the longitudinal direction is formed with an outer tapered surface and a slit for giving it elasticity, and the other end is provided with a screw portion for attaching to a column of an automatic lathe. An inner peripheral surface for holding the workpiece is formed around the periphery, and the workpiece inserted into the center opening by being attached to the automatic lathe is cut by the inner peripheral surface holding the workpiece. , Which is slidably held in the direction of rotation and axially slidable, and provided with a carbide member containing at least cobalt on the inner peripheral surface thereof, an intermediate layer provided on the carbide member, and a hard carbon film provided on the intermediate layer. Wherein the surface of the super hard member is uneven due to the removal of cobalt, and the surface of the hard carbon film is uneven so as to follow the uneven surface of the super hard member. I do.

In the method of forming a coating on a guide bush according to the present invention, the guide bush has a substantially cylindrical shape having a central opening penetrating in the axial direction, and has an outer peripheral tapered surface at one end in the longitudinal direction and elasticity thereof. The other end has a threaded portion for attaching to the column of the automatic lathe, and the inner peripheral surface for holding the workpiece is formed on the inner periphery of the portion where the outer peripheral tapered surface is formed. Workpiece inserted into the center opening by being attached to the automatic lathe,
An inner peripheral surface that holds the workpiece is slidably and axially slidably held near the cutting tool, a superhard member is provided on the inner peripheral surface, and an intermediate layer is provided on the superhard member. A method of forming a coating on a guide bush in which a hard carbon film is formed on an intermediate layer, wherein a step of forming irregularities by etching the surface of the super-hard material, and targeting an inner peripheral surface of the guide bush After the inside of the vacuum chamber was evacuated, the argon gas was introduced from the gas inlet into the vacuum chamber to form an intermediate layer by a sputtering method, and the intermediate layer was formed. The guide bush is arranged in the vacuum chamber so that the auxiliary electrode connected to the ground potential is inserted into the inner surface of the guide bush, and after exhausting the vacuum chamber, a gas containing carbon is introduced into the vacuum chamber from the gas inlet. And guy Characterized by a step of forming a hard carbon film DC voltage DC voltage is applied to an AC voltage is applied to the filaments to generate a plasma applied to the anode and to the guide bush to bush.

In the method of forming a coating on the guide bush of the present invention, the guide bush has a substantially cylindrical shape having a central opening penetrating in the axial direction, and has a tapered outer peripheral surface at one end in the longitudinal direction and elasticity thereof. The other end has a threaded portion for attaching to the column of the automatic lathe, and the inner peripheral surface for holding the workpiece is formed on the inner periphery of the portion where the outer peripheral tapered surface is formed. Workpiece inserted into the center opening by being attached to the automatic lathe,
An inner peripheral surface that holds the workpiece holds the workpiece in a rotatable and axially slidable manner near the cutting tool, and a carbide member containing at least cobalt is provided on the inner peripheral surface. A method of forming a coating on a guide bush in which an intermediate layer is provided and a hard carbon film is formed on the intermediate layer, wherein a step of forming irregularities by etching cobalt on the surface of the super hard material; A step of arranging the inner peripheral surface of the vacuum chamber so as to face the target, evacuating the vacuum chamber, introducing an argon gas into the vacuum chamber from a gas inlet, and forming an intermediate layer by sputtering. The guide bush is arranged in the vacuum chamber so that the auxiliary electrode connected to the ground potential is inserted into the inner surface of the guide bush in which the intermediate layer is formed, and the inside of the vacuum chamber is evacuated. A step of introducing a gas containing nitrogen into a vacuum chamber, applying a DC voltage to the guide bush, applying a DC voltage to the anode, applying an AC voltage to the filament to generate plasma, and forming a hard carbon film on the guide bush. And characterized in that:

In the method of forming a coating on the guide bush of the present invention, the guide bush has a substantially cylindrical shape having a central opening penetrating in the axial direction, and has an outer peripheral tapered surface at one end in the longitudinal direction and elasticity thereof. The other end has a threaded portion for attaching to the column of the automatic lathe, and the inner peripheral surface for holding the workpiece is formed on the inner periphery of the portion where the outer peripheral tapered surface is formed. The workpiece inserted into the center opening by being attached to the automatic lathe is held slidably and axially in the vicinity of the cutting tool by the inner peripheral surface holding the workpiece, A method for forming a coating on a guide bush in which a super hard member is provided on the inner peripheral surface, an intermediate layer is provided on the super hard member, and a hard carbon film is formed on the intermediate layer, Etching the surface A step of forming a more uneven,
The inner peripheral surface of the guide bush is arranged in a vacuum chamber so as to face the target, and after evacuation of the vacuum chamber, an argon gas is introduced into the vacuum chamber from a gas inlet, and an intermediate layer is formed by a sputtering method. Step and arrange the guide bush in the vacuum chamber so that the auxiliary electrode connected to the ground potential is inserted into the inner surface of the guide bush in which the intermediate layer is formed, and after evacuating the vacuum chamber, carbon is introduced from the gas inlet. Introducing a gas containing gas into the vacuum chamber, applying a high-frequency voltage to the guide bush, generating plasma, and forming a hard carbon film on the guide bush.

In the method of forming a coating on a guide bush according to the present invention, the guide bush has a substantially cylindrical shape having a central opening penetrating in the axial direction, and has an outer peripheral tapered surface at one end in the longitudinal direction and elasticity thereof. The other end has a threaded portion for attaching to the column of the automatic lathe, and the inner peripheral surface for holding the workpiece is formed on the inner periphery of the portion where the outer peripheral tapered surface is formed. Workpiece inserted into the center opening by being attached to the automatic lathe,
An inner peripheral surface that holds the workpiece holds the workpiece in a rotatable and axially slidable manner near the cutting tool, and a carbide member containing at least cobalt is provided on the inner peripheral surface. A method of forming a coating on a guide bush in which an intermediate layer is provided and a hard carbon film is formed on the intermediate layer, wherein a step of forming irregularities by etching cobalt on the surface of the super hard material; A step of arranging the inner peripheral surface of the vacuum chamber so as to face the target, evacuating the vacuum chamber, introducing an argon gas into the vacuum chamber from a gas inlet, and forming an intermediate layer by sputtering. The guide bush is arranged in the vacuum chamber so that the auxiliary electrode connected to the ground potential is inserted into the inner surface of the guide bush in which the intermediate layer is formed, and the inside of the vacuum chamber is evacuated. A gas containing oxygen is introduced into the vacuum chamber, a high frequency voltage is applied to the guide bush, and having a step of generating plasma to form a hard carbon film on the guide bush.

In the method of forming a coating on a guide bush according to the present invention, the guide bush has a substantially cylindrical shape having a central opening penetrating in the axial direction, and is provided with an outer peripheral tapered surface at one end in the longitudinal direction and elasticity thereof. The other end has a threaded portion for attaching to the column of the automatic lathe, and the inner peripheral surface for holding the workpiece is formed on the inner periphery of the portion where the outer peripheral tapered surface is formed. The workpiece inserted into the center opening by being attached to the automatic lathe is held slidably and axially in the vicinity of the cutting tool by the inner peripheral surface holding the workpiece, A method for forming a coating on a guide bush in which a super hard member is provided on the inner peripheral surface, an intermediate layer is provided on the super hard member, and a hard carbon film is formed on the intermediate layer, Etching the surface A step of forming a more uneven,
The inner peripheral surface of the guide bush is arranged in a vacuum chamber so as to face the target, and after evacuation of the vacuum chamber, an argon gas is introduced into the vacuum chamber from a gas inlet, and an intermediate layer is formed by a sputtering method. Step and arrange the guide bush in the vacuum chamber so that the auxiliary electrode connected to the ground potential is inserted into the inner surface of the guide bush in which the intermediate layer is formed, and after evacuating the vacuum chamber, carbon is introduced from the gas inlet. Introducing a gas containing gas into the vacuum chamber, applying a DC voltage to the guide bush, and generating plasma to form a hard carbon film on the guide bush.

In the method of forming a coating on the guide bush of the present invention, the guide bush has a substantially cylindrical shape having a central opening penetrating in the axial direction, and has an outer peripheral tapered surface at one end in the longitudinal direction and elasticity thereof. The other end has a threaded portion for attaching to the column of the automatic lathe, and the inner peripheral surface for holding the workpiece is formed on the inner periphery of the portion where the outer peripheral tapered surface is formed. Workpiece inserted into the center opening by being attached to the automatic lathe,
An inner peripheral surface that holds the workpiece holds the workpiece in a rotatable and axially slidable manner near the cutting tool, and a carbide member containing at least cobalt is provided on the inner peripheral surface. A method of forming a coating on a guide bush in which an intermediate layer is provided and a hard carbon film is formed on the intermediate layer, wherein a step of forming irregularities by etching cobalt on the surface of the super hard material; A step of arranging the inner peripheral surface of the vacuum chamber so as to face the target, evacuating the vacuum chamber, introducing an argon gas into the vacuum chamber from a gas inlet, and forming an intermediate layer by sputtering. The guide bush is arranged in the vacuum chamber so that the auxiliary electrode connected to the ground potential is inserted into the inner surface of the guide bush in which the intermediate layer is formed, and the inside of the vacuum chamber is evacuated. A gas containing oxygen is introduced into the vacuum chamber, a DC voltage is applied to the guide bush, and having a step of generating plasma to form a hard carbon film on the guide bush.

In the method of forming a coating on the guide bush of the present invention, the guide bush has a substantially cylindrical shape having a central opening penetrating in the axial direction, and has an outer peripheral tapered surface at one end in the longitudinal direction and elasticity thereof. The other end has a threaded portion for attaching to the column of the automatic lathe, and the inner peripheral surface for holding the workpiece is formed on the inner periphery of the portion where the outer peripheral tapered surface is formed. Workpiece inserted into the center opening by being attached to the automatic lathe,
An inner peripheral surface that holds the workpiece is slidably and axially slidably held near the cutting tool, a superhard member is provided on the inner peripheral surface, and an intermediate layer is provided on the superhard member. A method of forming a coating on a guide bush in which a hard carbon film is formed on an intermediate layer, wherein a step of forming irregularities by etching the surface of the super-hard material, and targeting an inner peripheral surface of the guide bush After the inside of the vacuum chamber was evacuated, the argon gas was introduced from the gas inlet into the vacuum chamber to form an intermediate layer by a sputtering method, and the intermediate layer was formed. The guide bush is arranged in the vacuum chamber so that the auxiliary electrode connected to the DC positive voltage is inserted into the inner surface of the guide bush, and after exhausting the vacuum chamber, the gas containing carbon is introduced into the vacuum chamber from the gas inlet. Introduce and mo Characterized by a step of forming the applied hard carbon film a DC voltage is applied by applying an AC voltage to the filament plasma is generated in the guide bush to the anode of the DC voltage Dobusshu.

In the method of forming a coating on the guide bush of the present invention, the guide bush has a substantially cylindrical shape having a central opening penetrating in the axial direction, and has an outer peripheral tapered surface at one end in the longitudinal direction and elasticity thereof. The other end has a threaded portion for attaching to the column of the automatic lathe, and the inner peripheral surface for holding the workpiece is formed on the inner periphery of the portion where the outer peripheral tapered surface is formed. Workpiece inserted into the center opening by being attached to the automatic lathe,
An inner peripheral surface that holds the workpiece holds the workpiece in a rotatable and axially slidable manner near the cutting tool, and a carbide member containing at least cobalt is provided on the inner peripheral surface. A method of forming a coating on a guide bush in which an intermediate layer is provided and a hard carbon film is formed on the intermediate layer, wherein a step of forming irregularities by etching cobalt on the surface of the super hard material; A step of arranging the inner peripheral surface of the vacuum chamber so as to face the target, evacuating the vacuum chamber, introducing an argon gas into the vacuum chamber from a gas inlet, and forming an intermediate layer by sputtering. The guide bush is arranged in a vacuum chamber so that an auxiliary electrode connected to a DC positive voltage is inserted into the inner surface of the guide bush in which the intermediate layer is formed, and the inside of the vacuum chamber is evacuated. A step of introducing a gas containing carbon into a vacuum chamber, applying a DC voltage to the guide bush, applying a DC voltage to the anode, applying an AC voltage to the filament to generate plasma, and forming a hard carbon film on the guide bush. And characterized in that:

In the method of forming a coating on a guide bush according to the present invention, the guide bush has a substantially cylindrical shape having a central opening penetrating in the axial direction, and has a tapered outer peripheral surface at one end in the longitudinal direction and elasticity thereof. The other end has a threaded portion for attaching to the column of the automatic lathe, and the inner peripheral surface for holding the workpiece is formed on the inner periphery of the portion where the outer peripheral tapered surface is formed. Workpiece inserted into the center opening by being attached to the automatic lathe,
An inner peripheral surface that holds the workpiece is slidably and axially slidably held near the cutting tool, a superhard member is provided on the inner peripheral surface, and an intermediate layer is provided on the superhard member. A method of forming a coating on a guide bush in which a hard carbon film is formed on an intermediate layer, wherein a step of forming irregularities by etching the surface of the super-hard material, and targeting an inner peripheral surface of the guide bush After the inside of the vacuum chamber was evacuated, the argon gas was introduced from the gas inlet into the vacuum chamber to form an intermediate layer by a sputtering method, and the intermediate layer was formed. The guide bush is arranged in the vacuum chamber so that the auxiliary electrode connected to the DC positive voltage is inserted into the inner surface of the guide bush, and after exhausting the vacuum chamber, the gas containing carbon is introduced into the vacuum chamber from the gas inlet. Introduce and mo A high-frequency voltage is applied to the Dobusshu,
Forming a hard carbon film on the guide bush by generating plasma.

In the method of forming a coating on the guide bush of the present invention, the guide bush has a substantially cylindrical shape having a central opening penetrating in the axial direction, and one end in the longitudinal direction is provided with an outer peripheral tapered surface and elasticity thereto. The other end has a threaded portion for attaching to the column of the automatic lathe, and the inner peripheral surface for holding the workpiece is formed on the inner periphery of the portion where the outer peripheral tapered surface is formed. Workpiece inserted into the center opening by being attached to the automatic lathe,
An inner peripheral surface that holds the workpiece holds the workpiece in a rotatable and axially slidable manner near the cutting tool, and a carbide member containing at least cobalt is provided on the inner peripheral surface. A method of forming a coating on a guide bush in which an intermediate layer is provided and a hard carbon film is formed on the intermediate layer, wherein a step of forming irregularities by etching cobalt on the surface of the super hard material; A step of arranging the inner peripheral surface of the vacuum chamber so as to face the target, evacuating the vacuum chamber, introducing an argon gas into the vacuum chamber from a gas inlet, and forming an intermediate layer by sputtering. The guide bush is arranged in a vacuum chamber so that an auxiliary electrode connected to a DC positive voltage is inserted into the inner surface of the guide bush in which the intermediate layer is formed, and the inside of the vacuum chamber is evacuated. The gas containing carbon is introduced into the vacuum chamber, a high frequency voltage is applied to the guide bush, and having a step of generating plasma to form a hard carbon film on the guide bush.

In the method of forming a coating on the guide bush of the present invention, the guide bush has a substantially cylindrical shape having a central opening penetrating in the axial direction, and has an outer peripheral tapered surface at one end in the longitudinal direction and elasticity therewith. The other end has a threaded portion for attaching to the column of the automatic lathe, and the inner peripheral surface for holding the workpiece is formed on the inner periphery of the portion where the outer peripheral tapered surface is formed. The workpiece inserted into the center opening by being attached to the automatic lathe is held slidably and axially in the vicinity of the cutting tool by the inner peripheral surface holding the workpiece, A method for forming a coating on a guide bush in which a super hard member is provided on the inner peripheral surface, an intermediate layer is provided on the super hard member, and a hard carbon film is formed on the intermediate layer, Etching the surface A step of forming a more uneven,
The inner peripheral surface of the guide bush is arranged in a vacuum chamber so as to face the target, and after evacuation of the vacuum chamber, an argon gas is introduced into the vacuum chamber from a gas inlet, and an intermediate layer is formed by a sputtering method. In the process, the guide bush is arranged in the vacuum chamber so that an auxiliary electrode connected to a DC positive voltage is inserted into the inner surface of the guide bush in which the intermediate layer is formed, and the inside of the vacuum chamber is evacuated. Is introduced into the vacuum chamber, a DC voltage is applied to the guide bush, plasma is generated, and a hard carbon film is formed on the guide bush.

In the method of forming a coating on the guide bush of the present invention, the guide bush has a substantially cylindrical shape having a central opening penetrating in the axial direction, and has an outer peripheral tapered surface at one end in the longitudinal direction and elasticity thereof. The other end has a threaded portion for attaching to the column of the automatic lathe, and the inner peripheral surface for holding the workpiece is formed on the inner periphery of the portion where the outer peripheral tapered surface is formed. Workpiece inserted into the center opening by being attached to the automatic lathe,
An inner peripheral surface that holds the workpiece holds the workpiece in a rotatable and axially slidable manner near the cutting tool, and a carbide member containing at least cobalt is provided on the inner peripheral surface. A method of forming a coating on a guide bush in which an intermediate layer is provided and a hard carbon film is formed on the intermediate layer, wherein a step of forming irregularities by etching cobalt on the surface of the super hard material; A step of arranging the inner peripheral surface of the vacuum chamber so as to face the target, evacuating the vacuum chamber, introducing an argon gas into the vacuum chamber from a gas inlet, and forming an intermediate layer by sputtering. The guide bush is arranged in a vacuum chamber so that an auxiliary electrode connected to a DC positive voltage is inserted into the inner surface of the guide bush in which the intermediate layer is formed, and the inside of the vacuum chamber is evacuated. The gas containing carbon is introduced into the vacuum chamber, a DC voltage is applied to the guide bush, and having a step of generating plasma to form a hard carbon film on the guide bush.

[Operation] The guide bush according to the present invention, which is provided on a guide bush device of an automatic lathe and rotatably supports a workpiece, is provided with an intermediate layer provided on the inner peripheral surface thereof.
When the hard carbon film is provided, a configuration is employed in which the surface of the hard carbon film that comes into contact with the workpiece is made uneven. Alternatively, the guide bush of the present invention is provided with a super hard member on the inner peripheral surface thereof, and when a hard carbon film is provided via an intermediate layer formed on the upper surface of the super hard member, a hard carbon film which is in contact with a workpiece is formed. A configuration in which the surface is uneven is adopted.

When the surface of the hard carbon film in contact with the workpiece is made uneven, the contact area between the hard carbon film and the workpiece is smaller than that of the conventional hard carbon film having no uneven surface. Can be reduced. Therefore, it is an excellent characteristic of the hard carbon film,
It is possible to further promote low friction characteristics.

Further, the oil supplied between the inner peripheral surface of the guide bush and the workpiece can be held in the concave portion of the hard carbon film having the surface irregularities. As a result, the contact resistance between the workpiece rotating on the inner peripheral surface of the guide bush and sliding in the axial direction and the hard carbon film is reduced, and wear of the hard carbon film can be suppressed. Therefore, in the guide bush of the present invention, the durability of the hard carbon film formed on the inner peripheral surface can be improved, and the reliability of the guide bush for long-term use can be improved.

Further, according to the n-type guide bush of the present invention, the cobalt (C) on the surface in contact with the intermediate layer of the cemented carbide member composed of tungsten (W), carbon (C) and cobalt (Co)
o) is adopted. Then, a hard carbon film is provided on the upper surface of the super hard member from which cobalt (Co) has been removed, via an intermediate layer.

As described above, in the guide bush of the present invention, the intermediate layer is provided on the upper surface of the super hard member from which cobalt (Co) has been removed, and the hard carbon film is further formed thereon. Therefore, the hard carbon film of the present invention can be formed with good adhesion on the inner peripheral surface of the guide bush, and the problem of peeling does not occur. Therefore, the service life of the guide bush can be significantly extended,
It is possible to improve reliability for long-term use.

The inventors believe that these effects are obtained for the following reasons. The surface states before and after removing cobalt on the surface of the superhard member in contact with the intermediate layer were observed with a scanning electron microscope (SEM).

Before the cobalt was removed from the surface of the cemented carbide member, there was observed a trace of grinding the inner peripheral surface of the cemented carbide member. On the other hand, no machining mark was observed on the surface of the cemented carbide member after removing cobalt.

Further, even when the surface of the super hard member was observed with the naked eye, the difference was obvious. That is, the surface of the cemented carbide member before removing cobalt had a polished surface in a mirror-like state, whereas the surface of the cemented carbide member after removing cobalt had a mirror-finished state instead of a mirror-like surface.

This is because, when the cobalt on the surface of the cemented carbide member that comes into contact with the intermediate layer is removed, the cobalt functions as a binder, so that tungsten and carbon bonded to the binder by the sintering process also fall off, As described above, no processing marks are observed, and the surface is in a satin state.

As described above, since the machining marks on the surface of the cemented carbide member in contact with the intermediate layer disappear and are not observed, and the matte state is obtained, the adhesion of the hard carbon film is further improved. In particular, regarding processing marks, in the intermediate layer formed at the processing mark location, a film stress such as elongation or compression is generated at that location, and due to this film stress,
It is considered that poor adhesion of the intermediate layer has occurred, and the phenomenon that the adhesion is deteriorated due to the film stress does not occur due to the disappearance of the processing mark. As a result,
In the guide bush of the present invention, the phenomenon that the intermediate layer peels does not occur, therefore, the adhesion of the hard carbon film formed on the upper surface of the intermediate layer is also improved, and the service life of the guide bush is greatly extended as compared with the conventional art. And reliability for long-term use is improved.

This hard carbon film is a black film and has properties very similar to diamond. That is, the hard carbon film has excellent characteristics such as high mechanical hardness, low coefficient of friction, good electrical insulation, high thermal conductivity, and high corrosion resistance. For this reason, the guide bush of the present invention can suppress the wear of the inner peripheral surface that comes into contact with the workpiece and suppress the occurrence of scratches on the workpiece in heavy cutting in which the cutting amount is large and the processing speed is large. And the occurrence of seizure between the guide bush and the workpiece can be suppressed.

Further, in the guide bush of the present invention, a hard carbon film is provided below the intermediate layer on the inner peripheral surface of the guide bush via a superhard member having high hardness. By providing a high-hardness super-hard member under the hard carbon film in this manner, local peeling and wear of the hard carbon film can be suppressed, and the reliability of the guide bush for long-term use can be further improved. Can be.

Further, in the present invention, a structure in which an intermediate layer is provided between the super hard member and the hard carbon film is employed.
As the intermediate layer, in the guide bush of the present invention, a structure constituted by a single layer film or a structure constituted by a laminated film is adopted. When the intermediate layer is composed of a single layer film, a silicon carbide film (SiC) or a tungsten carbide film (WC)
When it is constituted by an alloy material film containing carbon, such as a titanium film (Ti) or chromium (Cr), and a silicon film (Si) or a germanium film (Ge). Constitute.

When the intermediate layer is interposed between the super-hard member and the hard carbon film as described above, the adhesion of the hard carbon film increases. When the intermediate layer and the hard carbon film were peeled off in detail using a conventional guide bush, the intermediate layer and the hard carbon film could not obtain the adhesion with cobalt contained as a binder in the super hard member, It was peeled off from that location. The cause is not well understood, but one of the causes is thought to be that cobalt is oxidized, an oxide film with poor adhesion is formed, and the hard carbon film and the intermediate layer peel off from the inner peripheral surface of the guide bush. I guess.

Therefore, in the guide bush of the present invention, cobalt contained as a binder in the super hard member is removed from the surface on which the intermediate layer is formed on the inner peripheral surface of the super hard member.
In this way, cobalt that causes poor adhesion of the intermediate layer is removed from the inner peripheral surface of the guide bush. Therefore, the hard carbon film can be formed on the inner peripheral surface of the guide bush with good adhesion, and as a result, the peeling phenomenon of the hard carbon film on the inner peripheral surface of the guide bush does not occur.

In the method of forming a hard carbon film on a guide bush according to the present invention, an auxiliary electrode connected to a ground potential is arranged at the center of the opening on the inner surface of the opening of the guide bush to form a hard carbon film. Then, a negative DC voltage or a high-frequency voltage is applied to the guide bush.

As a result, an auxiliary electrode connected to the ground potential is provided on the inner surface of the guide bush opening where the electrodes of the same potential face each other, so that the same potential does not face each other. Such a potential state is the most desirable state for plasma enhanced chemical vapor deposition, and no hollow discharge occurs. Therefore, a hard carbon film having good adhesion can be formed on the guide bush.

Furthermore, in the method for forming a hard carbon film of the present invention, the auxiliary electrode is disposed on the inner surface of the opening of the guide bush as described above, and the potential characteristics become uniform on the inner surface of the opening in the longitudinal direction of the guide bush. . As a result, there is no generation of a film thickness distribution of the hard carbon film formed on the inner surface of the opening of the guide bush, and an effect that a uniform film thickness can be formed between the opening end face and the inner side of the opening.

Further, in the method for forming a hard carbon film according to the present invention, a DC positive voltage from an auxiliary electrode power source is applied to an auxiliary electrode provided at the center of the inner surface of the sample opening to form the hard carbon film. . For this reason, an effect of collecting electrons in a region around the auxiliary electrode to which a DC positive voltage is applied occurs,
The area around the auxiliary electrode has a high electron density.

As described above, when the electron density is increased, the collision probability between the gas molecules containing carbon and the electrons is inevitably increased, ionization of the gas molecules is promoted, and the plasma density in the region around the auxiliary electrode is increased. . For this reason, in the film forming method of the present invention in which a DC positive voltage is applied to the auxiliary electrode to form a hard carbon film, the film formation speed of the hard carbon film is smaller than when no DC positive voltage is applied to the auxiliary electrode. It will be much higher.

Further, when the size of the opening of the sample becomes smaller and the gap between the inner surface of the opening and the auxiliary electrode becomes smaller, when a hard carbon film is formed without applying a DC positive voltage to the auxiliary electrode, plasma is generated on the inner surface of the opening. It does not occur and a film cannot be formed. On the other hand, in the method for forming a hard carbon film of the present invention, a DC positive voltage is applied from an auxiliary electrode power source to an auxiliary electrode disposed on the inner surface of the opening to forcibly collect electrons on the inner surface of the opening around the auxiliary electrode. Therefore, plasma can be generated around the auxiliary electrode.

Therefore, in the method of forming a hard carbon film using an auxiliary electrode to which a DC positive voltage is not applied, the present invention using an auxiliary electrode to which a DC positive voltage is applied is used even for a sample having a small opening size where a film cannot be formed. If a method for forming a hard carbon film is applied, a film can be formed.

[0063]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a guide bush according to a preferred embodiment of the present invention and a method for forming an intermediate layer and a hard carbon film on the guide bush will be described below with reference to the drawings. .

[Description of Structure of Numerically Controlled Automatic Lathe: FIG. 8] Before describing the structure of the guide bush and the method of forming a hard carbon film on the guide bush in the embodiment of the present invention, this guide bush will be applied. The configuration of the guide bush device to which the guide bush is applied will be described with reference to FIG. FIG. 8 is a sectional view showing a fixed type guide bush device which is used as a guide bush device in a state where the guide bush is fixed and a workpiece rotates on the inner peripheral surface of the guide bush.

The headstock 17 is slidable on the bed (not shown) of a numerically controlled automatic lathe (not shown) in the horizontal direction of FIG. The headstock 17 is provided with a spindle 19 rotatably supported by a bearing 21. A collet chuck 13 is provided at the tip of the spindle 19.
Is installed.

The collet chuck 13 is disposed in the center hole of the chuck sleeve 41. The outer tapered surface 13a at the tip of the collet chuck 13 and the inner tapered surface 41a of the chuck sleeve 41 are in surface contact with each other.

Further, a spring 25 is provided at the rear end of the collet chuck 13 in the intermediate sleeve 29. And
The collet chuck 13 can be pushed out of the intermediate sleeve 29 by the action of the elastic force of the spring 25.

The position of the tip of the collet chuck 13 is in contact with a cap nut 27 screwed to the tip of the main shaft 19 to regulate the position. This cap nut 27
Is provided to prevent the collet chuck 13 from jumping out of the intermediate sleeve 29 due to the spring force of the spring 25.

At the rear end of the intermediate sleeve 29, a chuck opening / closing mechanism 31 is provided via the intermediate sleeve 29.
By opening and closing the chuck opening / closing claws 33, the collet chuck 13 is opened / closed, and the workpiece 51 can be gripped or released.

That is, when the distal ends of the chuck opening / closing claws 33 of the chuck opening / closing mechanism 31 move so as to open each other,
The portion of the chuck opening / closing claw 33 in contact with the intermediate sleeve 29 moves leftward in FIG. 7 and pushes the intermediate sleeve 29 leftward. As the intermediate sleeve 29 moves leftward, the chuck sleeve 41 that is in contact with the left end of the intermediate sleeve 29 moves leftward.

The collet chuck 13 is prevented from jumping forward from the spindle 19 by the cap nut 27 screwed to the tip of the spindle 19 as described above. Therefore, by the movement of the chuck sleeve 41 to the left, the outer taper 13a of the collet chuck 13 and the inner taper 41a of the chuck sleeve 41 are strongly pushed and move along the tapered surface.
As a result, the diameter of the inner peripheral surface of the collet chuck 13 is reduced, and the workpiece 51 can be gripped.

When the workpiece 51 is released by increasing the diameter of the inner peripheral surface of the collet chuck 13, the chuck sleeve 41 is moved to the left by moving the tips of the chuck opening / closing claws 33 so as to close each other. Excluding the pushing force in the direction. Then, the intermediate sleeve 29 and the chuck sleeve 41 move rightward in FIG. 8 by the restoring force of the spring 25.

Therefore, the pressing force between the outer peripheral tapered surface 13a of the collet chuck 13 and the inner peripheral tapered surface 41a of the chuck sleeve 41 is eliminated. As a result, the diameter of the inner peripheral surface of the collet chuck 13 is increased by its own elastic force, and the workpiece 51 can be released.

Further, a column 35 is provided in front of the headstock 17.
The guide bush device 37 of a fixed type which is arranged on the center line of the main shaft is provided. The guide bush device 37 shown in FIG.
A fixed type guide bush device 37 used to fix the guide bush 11 and rotate the workpiece 51 on the inner peripheral surface 11b of the guide bush 11 as described above, and the holder 39 fixed to the column 35. The bush sleeve 23 is arranged in the center hole of the. An inner peripheral tapered surface 23a is provided at the tip of the bush sleeve 23.

In the center hole of the bush sleeve 23, a guide bush 11 having a tapered outer peripheral surface 11a at the end is disposed.

By rotating the adjusting nut 43 provided at the rear end of the guide bush device 37, the gap between the inner diameter of the guide bush 11 and the outer shape of the workpiece 51 can be adjusted. When the adjustment nut 43 is rotated, the inner peripheral taper surface 23a of the bush sleeve 23 and the outer peripheral taper surface 11a of the guide bush 11 become the inner peripheral taper surface 23a and the outer peripheral taper surface 1 like the collet chuck 13.
1a are mutually pressed and the inner diameter of the guide bush 11 is reduced.

A cutting tool 45 is provided further forward of the guide bush device 37. The workpiece 51 is gripped by the collet chuck 13 of the spindle 19 and supported by the guide bush device 37.
The workpiece 51 protruding into the machining area through the workpiece 7 is cut into a predetermined shape by a combined movement of the forward and backward movement of the cutting tool 45 and the movement of the headstock 17.

[Description of Structure of Rotary Guide Bush Device: FIG. 9] Next, the configuration of a rotary guide bush device used in a state where the guide bush for gripping a workpiece is rotated will be described with reference to FIG. I do. FIG. 9 is a cross-sectional view showing a configuration of a rotary type guide bush device. In FIG. 9, the same parts as those in FIG. 8 are denoted by the same reference numerals.

The rotary guide bush device includes a guide bush device in which the collet chuck 13 and the guide bush 11 rotate in synchronization, and a guide bush device in which the collet chuck 13 and the guide bush 11 rotate without synchronization. The guide bush device 37 shown in FIG. 9 is a rotary type guide bush device 37 in which the collet chuck 13 and the guide bush 11 rotate in synchronization.

The rotary type guide bush device 37 includes a rotary drive rod 4 protruding from the cap nut 27 of the main shaft 19.
7, the guide bush device 37 is driven. In addition to the drive by the rotary drive rod 47, there is also a drive in which the guide bush device 37 is driven by a gear or a belt pulley.

This rotary type guide bush device 37 is
The center hole of the holder 39 fixed to the column 35 is provided with the bearing 21.
The bush sleeve 23 is arranged so as to be rotatable via the. Further, the guide bush 11 is arranged in the center hole of the bush sleeve 23.

The bush sleeve 23 and the guide bush 1
1 is the same structure as the structure described with reference to FIG.
The guide bush 11 is rotated by rotating an adjustment nut 43 provided at the rear end of the guide bush device 37.
Of the guide bush 11 and the outer diameter of the workpiece 51 can be adjusted.

The configuration of the guide bush device described with reference to FIG. 9 is the same as the configuration described with reference to FIG. 8 except that the guide bush device 37 is a rotary type. Omitted.

[Description of Structure of Guide Bush: FIG. 3] Next, the structure of a guide bush for forming a hard carbon film according to the embodiment of the present invention will be described with reference to FIG. As is apparent from the above description, the fixed type guide bush and the rotary type guide bush have substantially the same structure and operate in the same manner.

FIG. 3 is a sectional view showing a guide bush according to the embodiment of the present invention. The guide bush shown in FIG. 3 shows an open and free state. As shown in FIG. 3, the guide bush 11 has an outer peripheral tapered surface 11a at an outer peripheral portion at one end in the longitudinal direction, and has a thread portion 11f at an outer peripheral portion at the other end.

Further, a penetrating opening having a different opening diameter is provided at the center of the guide bush 11. An inner peripheral surface 11b for holding the workpiece 51 is provided on the inner periphery on the side where the outer peripheral tapered surface 11a is provided. In the area other than the inner peripheral surface 11b, a step portion 11g having an inner diameter larger than the inner diameter of the inner peripheral surface 11b is formed.

Further, the guide bush 11 is provided with a slit 11c from the outer peripheral tapered surface 11a to the spring portion 11d. The slits 11c are provided at three places at intervals of 120 °.

By pressing the outer peripheral taper surface 11a of the guide bush 11 against the inner peripheral taper surface of the bush sleeve, the spring portion 11d bends, and the clearance between the inner peripheral surface 11b and the workpiece 51 can be adjusted. it can.

The guide bush 11 has a spring 1
A fitting portion 11e is provided between 1d and the screw portion 11f. The guide bush 11 is formed by the fitting portion 11e.
Can be arranged on the centerline of the spindle and parallel to the centerline of the spindle.

The guide bush 11 is made of alloy tool steel (SKS). After forming the outer shape and the inner shape, quenching and tempering are performed. Further, a superhard member having a thickness of 2 mm to 5 mm is fixed to the inner peripheral surface 11b of the guide bush 11 by brazing means to form a superhard member 12. As the cemented carbide member, Japanese Industrial Standard (JIS) type G No. 2 is often used, and it is 87% to 90% tungsten (W).
The composition contains 5% to 7% of carbon (C) and 5% to 7% of cobalt (Co) as a binder.

The guide bush 11 has a gap of 5 μm to 10 μm in the radial direction between the inner peripheral surface 11b and the workpiece 51 when the guide bush 11 is open. For this reason, abrasion of the inner peripheral surface 11b of the guide bush 11 due to entry and exit of the workpiece 51 poses a problem. Further, the guide bush 11 slides at a high speed between the inner peripheral surface 11b and the workpiece 51 as described above,
In addition, there is a problem that image sticking occurs due to excessive pressing force of the workpiece 51 against the inner peripheral surface 11b due to the cutting load.

[First Example of Guide Bush: FIG. 1] The guide bush 11 of the present invention employs a structure as shown in FIG. FIG. 1 is an enlarged sectional view showing an inner peripheral surface of a guide bush according to an embodiment of the present invention. The thickness ratio of the hard carbon film to the intermediate layer and the super hard member is 10
In FIG. 1, the thickness of the superhard member is shown to be extremely thin.

As shown in FIG. 1, the super hard member 12 is sequentially provided on the inner peripheral surface 11b of the guide bush 11 (see FIG. 3).
The hard carbon film 15 is provided on the surface that comes into contact with the intermediate layer 14 and the workpiece 51.

The guide bush 11 according to the present invention, which is provided on a guide bush device of an automatic lathe and rotatably supports the workpiece 51, is provided with a hard carbon film 15 via an intermediate layer 14 provided on its inner peripheral surface 11b. When providing
Surface 15 of hard carbon film 15 in contact with workpiece 51
A configuration in which a is uneven is adopted. Alternatively, the guide bush 11 of the present invention is provided with the super hard member 12 on the inner peripheral surface 11b thereof, and when the hard carbon film 15 is provided through the intermediate layer 14 formed on the upper surface of the super hard member 12, the guide bush 11 is A configuration is employed in which the surface 15a of the hard carbon film 15 that makes contact is made uneven.

When the surface 15a of the hard carbon film 15 that is in contact with the workpiece 51 is made uneven, the hard carbon film 15 and the workpiece are harder than the conventional hard carbon film having no uneven surface. The area of contact with 51 can be reduced. Therefore, it is possible to further promote the low friction characteristics, which are the excellent characteristics of the hard carbon film 15. Further, since the surface 15a of the hard carbon film 15 is formed as an uneven surface, the oil supplied between the inner peripheral surface 11b of the guide bush 11 and the workpiece 51 is held in the concave portion on the surface of the hard carbon film 15. The workpiece 51 can be rotated and slid in the axial direction with low friction.

As a result, the inner peripheral surface 1 of the guide bush 11
1b, the contact resistance between the workpiece 51 rotating in the axial direction and the hard carbon film 15 is reduced.
5 can be suppressed. Therefore, in the guide bush 11 of the present invention, the durability of the hard carbon film 15 formed on the inner peripheral surface 11b can be improved, and the reliability of the guide bush 11 for long-term use can be improved.

The surface of the superhard member 12 which comes into contact with the intermediate layer 14 selectively removes cobalt (Co) functioning as a binder of the superhard member 12.
That is, the cemented carbide member 1 from which the cobalt (Co) has been removed.
2. A hard carbon film 15 is provided on the upper surface with an intermediate layer 14 interposed therebetween.

As a result, the hard carbon film 15 of the present invention can be formed with good adhesion on the inner peripheral surface 11b of the guide bush 11, and the problem of peeling does not occur. Therefore, the service life of the guide bush 11 can be greatly extended as compared with the conventional art, and the reliability for long-term use can be improved.

The inventors believe that the superior features of the guide bush 11 of the present invention have been obtained for the following reasons. The surface states before and after removing cobalt on the surface of the superhard member 12 in contact with the intermediate layer 14 were observed with a scanning electron microscope (SEM).

On the surface of the cemented carbide member 12 before removal of cobalt, there was observed a trace of grinding the inner peripheral surface of the cemented carbide member 12. On the other hand, no machining marks were observed on the surface of the superhard member 12 from which cobalt had been removed.

When the surface of the super hard member 12 was observed with the naked eye, the difference was obvious. That is, the super hard member 12
The surface of the superhard member 12 from which cobalt had been removed was in a mirror-finished state instead of a mirror-finished surface, whereas the surface before removing cobalt was in a mirror-finished state.

This is because the super hard member 1 in contact with the intermediate layer 14
When the cobalt on the surface of the 23 was removed, this cobalt functioned as a binder, so that tungsten and carbon bonded by the binder and the sintering process were also peeled off, and as described above, no processing marks were observed. It is in a satin state.

As described above, since the processing marks on the surface of the cemented carbide member 12 that are in contact with the intermediate layer 14 disappear and are not observed, and the matte state is provided, the adhesion of the hard carbon film 15 is further improved. . In particular, regarding the processing mark, the intermediate layer 14 formed at the processing mark position has a film stress such as elongation or compression at the position, and this film stress causes poor adhesion of the intermediate layer 14. It is believed that the disappearance of the processing trace does not cause a phenomenon that the adhesion due to the film stress is deteriorated. As a result, the guide bush 11 of the present invention
In this case, the phenomenon that the intermediate layer 14 is not peeled off does not occur, and therefore, the adhesion of the hard carbon film 15 formed on the upper surface of the intermediate layer 14 is also improved, and the service life of the guide bush 11 is significantly extended. And reliability for long-term use is improved.

The hard carbon film 15 is a black film and has properties very similar to diamond. That is, the hard carbon film 15 has excellent characteristics such as high mechanical hardness, low coefficient of friction, good electrical insulation, high thermal conductivity, and high corrosion resistance. For this reason, the guide bush 11 of the present invention can suppress wear of the inner peripheral surface in contact with the workpiece 51 in heavy cutting in which the cutting amount is large and the processing speed is large, and the generation of scratches on the workpiece is reduced. And the guide bush 11 and the workpiece 51
Can be suppressed from occurring.

Further, in the guide bush 11 of the present invention, a superhard member 12 having high hardness is formed below the intermediate layer 14 on the inner peripheral surface 11b, and a hard carbon film 15 is provided.
When the superhard member 12 having high hardness is provided below the hard carbon film 15, local peeling or wear of the hard carbon film 15 can be suppressed, and the reliability of the guide bush 11 for long-term use can be further improved. Can be further improved.

Further, in the present invention, a structure in which an intermediate layer 14 is provided between the super hard member 12 and the hard carbon film 15 is employed. In the case of the guide bush of the present invention, when the intermediate layer 14 is formed of a single-layer film as in the first example, the intermediate layer 14 contains carbon such as a silicon carbide film (SiC) or a tungsten carbide film (WC). It is composed of an alloy material film.

When the intermediate layer 12 is interposed between the super hard member 12 and the hard carbon film 15, the adhesion of the hard carbon film 15 is increased. This is the super hard member 12
This is because the intermediate layer 14 suppresses the phenomenon that cobalt contained in the hard carbon film 15 is dissolved in the carbon contained in the hard carbon film 15.

That is, the phenomenon that cobalt contained as a binder in the super hard member 12 reacts with carbon of the hard carbon film 15 does not occur. For this reason, the hard carbon film 15 can be formed on the inner peripheral surface of the guide bush 11 with good adhesion 11b, and as a result, the peeling phenomenon of the hard carbon film 15 on the inner peripheral surface of the guide bush does not occur.

The thickness of the hard carbon film 15 provided on the inner peripheral surface 11b of the guide bush 11 is from 1 μm to 10 μm.
μm. Further, in the guide bush 11 of the present invention,
The intermediate layer 14 made of a carbon-containing alloy material film has a thickness of about 0.5 μm. And as described below,
In the present invention, since the intermediate layer 14 is formed by a sputtering method and the hard carbon film 15 is formed by a plasma-enhanced chemical vapor deposition method, the above-described intermediate layer 14 and hard carbon film 15 have the following thicknesses. A film is formed so as to follow the irregularities, and irregularities can be formed on the surface 15 a of the hard carbon film 15.

Next, an embodiment of a method for forming a film of the intermediate layer and the hard carbon film on the guide bush will be described.

[Description of Method for Removing Cobalt from Carbide Member Surface Region] First, cobalt functioning as a binder is removed from the surface region of the carbide member 12 formed on the inner peripheral surface 11 b of the guide bush 11. This removal of cobalt is preferably performed by wet etching.

As a wet etching solution for selectively removing cobalt, a mixed solution of sodium hydroxide (NaOH) and hydrogen peroxide solution (H 2 O 2) is used. Alternatively, cobalt may be selectively etched with a hydrogen peroxide solution (H2 O2). In this mixed solution, tungsten and carbon, which are other constituent materials of the super hard member 12, and an alloy tool (S, which is a constituent material of the guide bush 11)
KS) is not etched at all and only cobalt can be selectively etched.

The etching of cobalt with a mixed solution of sodium hydroxide (NaOH) and aqueous hydrogen peroxide (H 2 O 2) is performed at a liquid temperature of room temperature, and the etching time is 3 to 5 hours. Soak in
The etching of cobalt using aqueous hydrogen peroxide (H2 O2) may be performed under substantially the same conditions.

In the above description, the embodiment has been described in which cobalt constituting the superhard member 12 is removed by wet etching, but other constituent materials of the superhard member 12 are etched to form the superhard member 12. May be formed on the surface of the substrate. When the super hard member 12 is not formed on the inner peripheral surface 11b of the guide bush 11, the alloy tool steel constituting the guide bush 11 may be etched to form the irregularities.

Next, a method of forming an intermediate layer on a guide bush in which cobalt has been removed from the surface region of the superhard member will be described with reference to FIG. FIG. 4 is a cross-sectional view illustrating a method of forming an intermediate layer on a guide bush according to the embodiment of the present invention. Hereinafter, description will be made with reference to FIG. 4 and FIG. 1 alternately.

[Method of Forming Intermediate Layer: FIGS. 4 and 1] As shown in FIG.
A target 55 made of a one-to-one alloy of tungsten and carbon as materials is arranged. And this target 55
The guide bush 11 that forms the intermediate layer 14 is arranged on the upper surface of the superhard member 12 so as to face the surface. At this time, the guide bush 11 is arranged so that the longitudinal direction of the opening is perpendicular to the surface of the target 55.

The guide bush 11 is connected to a DC power supply 73. Further, the target 55 is connected to a target power supply 57. Then, the vacuum chamber 61 is evacuated by an exhaust means (not shown).
The inside is evacuated from the exhaust port 65 so that the degree of vacuum becomes 3 × 10 ⁻⁵ torr or less. Thereafter, an argon (Ar) gas is introduced as a sputtering gas from the gas inlet 63 to adjust the degree of vacuum in the vacuum chamber 61 to 3 × 10 ⁻³ torr.

Thereafter, a negative DC voltage of -50 V is applied to the guide bush 11 from the DC power supply 73,
-5 from the target power supply 57 to the target 55
A DC voltage of 00 V to 600 V is applied.

Then, plasma is generated inside the vacuum chamber 61, and the surface of the target 55 is sputtered by ions in the plasma. The material of the intermediate layer 14 of tungsten and carbon that has been hammered from the surface of the target 55 adheres to the inner peripheral surface of the guide bush 11 to form the intermediate layer 14 made of tungsten carbide on the super hard member 12 of the guide bush 11. Can be formed.

The intermediate layer 14 made of the tungsten carbide film is formed with a thickness of about 0.5 μm. As described above, in the formation of the tungsten carbide having a thickness of about 0.5 μm, the surface of the intermediate layer 14 is formed so as to follow the irregularities formed on the surface of the lower super-hard member 12. Irregularities are formed.

[Method of Forming Hard Carbon Film] Next, a method of forming a hard carbon film on the guide bush 11 on which the intermediate layer 14 has been formed will be described with reference to FIGS. 5, 6 and 7. FIG. First, a first example of a method for forming a hard carbon film will be described with reference to FIG. FIG. 5 is a sectional view showing a method for forming a hard carbon film on a guide bush according to the embodiment of the present invention. Hereinafter, description will be given with reference to FIG. 5 showing an apparatus for forming a hard carbon film and FIG. 3 showing a guide bush alternately.

[First Example of Method of Forming Hard Carbon Film: FIGS. 5 and 3] As shown in FIG. 5, a hard carbon film is provided on a top surface of an intermediate layer in a vacuum chamber 61 having a gas inlet 63 and an exhaust port 65. A guide bush 11 for forming a carbon film is arranged.
At this time, a dummy member 53 is arranged on the outer peripheral tapered surface 11a side of the opening end surface of the guide bush 11.

The dummy member 53 has a columnar shape, and has an opening having an inner diameter substantially the same as the opening of the inner peripheral surface 11b of the guide bush 11 at the center thereof. The outer diameter of the dummy member 53 is the same as the size of the end face of the guide bush 11. That is, the dummy member 53 has a ring shape.

On the inner surface of the opening of the guide bush 11, an auxiliary electrode 71 connected to the ground potential is provided so as to be inserted. At this time, the auxiliary electrode 71 is
Is arranged at the center of the opening.

The degree of vacuum in the vacuum chamber 61 is 3 × 10 ^−5.
The air is evacuated from the exhaust port 65 by an exhaust means (not shown) so that the pressure is not more than torr. Then, the gas inlet 6
3. Benzene (C6 H6) is introduced into the vacuum chamber 61 as a gas containing carbon from 3 and the pressure in the vacuum chamber 61 is increased to 5.times.10.
^-3 torr.

Thereafter, a DC voltage is applied to the guide bush 11 from the DC power supply 73, a DC voltage is applied to the anode 79 from the anode power supply 75, and an AC voltage is applied to the filament 81 from the filament power supply 77.

At this time, a DC voltage applied from the DC power supply 73 to the guide bush 11 is −3 kV, and a DC voltage applied from the anode power supply 75 to the anode 79 is +50 V. Further, a voltage applied from the filament power supply 77 to the filament 81 is an AC voltage of 10 V so that a current of 30 A flows. Then, plasma is generated in a region around the auxiliary electrode 71 of the guide bush 11 in the vacuum chamber 61, and the hard carbon film 15 is formed on the inner peripheral surface 11 b of the guide bush 11.

As described above, the hard carbon film 15 is formed by the plasma-enhanced chemical vapor deposition method, and in the film formation in the plasma-enhanced chemical vapor deposition method, the film can be formed with good step coverage. Therefore, the hard carbon film 15 can be formed on the inner peripheral surface 11b of the guide bush 11 so as to follow the unevenness of the surface of the intermediate layer 14, and the unevenness can be formed on the surface 15a.

By the auxiliary electrode 71 arranged to be inserted into the inner surface of the opening of the guide bush 11, the same potential does not face each other in the inner surface region of the opening. Therefore, there is no occurrence of hollow discharge, which is an abnormal discharge, and the adhesion of the hard carbon film formed on the inner surface of the opening of the guide bush 11 is improved. Further, the potential characteristics become uniform on the inner surface of the opening in the longitudinal direction of the guide bush 11, and the thickness distribution of the hard carbon film formed on the inner surface of the opening does not occur. can do.

The auxiliary electrode 71 is connected to the guide bush 11
It is sufficient that the size is smaller than the opening size, and a plasma forming region which is preferably a gap of about 4 mm is provided.
The auxiliary electrode 71 may be made of a metal material such as stainless steel. The sectional shape of the auxiliary electrode 71 is circular, and the auxiliary electrode 71 is inserted into the guide bush 11 so that the auxiliary electrode 71 is aligned with the opening end surface of the dummy member 53 or the auxiliary electrode 71 extends from the dummy member 53 end surface.
Of the dummy member 5
(3) The length is set so as not to protrude from the end face but to be 1 mm to 2 mm deeper than the end face.

As described above, the dummy member 53 is disposed on the open end surface of the guide bush 11. As described above, the size of the opening at the center of the dummy member 53 and the size of the opening of the guide bush 11 are substantially the same. This dummy member 53 plays a role described below. That is, in the method of forming the hard carbon film shown in FIG. 5, plasma is generated on the inner surface of the guide bush 11 and the outer peripheral portion of the guide bush 11.

The end face of the guide bush 11 tends to concentrate electric charges, and the end face area of the guide bush 11 has a higher electric charge than the inner surface of the guide bush 11, that is, a so-called edge effect occurs. Here, the plasma intensity in the vicinity of the end face of the guide bush 11 is higher than in other regions, and is also unstable. Further, the end region of the guide bush 11 is affected by both the plasma on the inner surface of the guide bush 11 and the plasma on the outer peripheral portion of the guide bush 11.

When a hard carbon film is formed in such a state, a few mm from the open end face of the guide bush 11
The adhesiveness of the hard carbon film is slightly inferior between the deep region and the other region, and the film quality is slightly different.

Therefore, if a hard carbon film is formed by disposing the dummy member 53 on the open end surface of the guide bush 11,
The region having the different film quality and adhesion is not formed on the inner surface of the guide bush 11, but is formed on the inner surface of the opening of the dummy member 53.

When a hard carbon film was formed using an apparatus as shown in FIG.
A region having a width of 1 mm to 2 mm and different film quality and adhesion was formed at a depth of about 4 mm from the opening end face of No. 1. Therefore, a dummy member 53 having an opening size almost the same as the opening size of the guide bush 11 and having a length of 10 mm was arranged on the opening end face of the guide bush 11, and a film was formed under the conditions for forming the hard carbon film described above. . As a result, regions having different film qualities and adhesion were formed on the dummy member 53, and no regions having different film qualities and adhesion were formed on the inner surface of the guide bush 11 at all.

[Second Example of Method of Forming Hard Carbon Film: FIGS. 6 and 3] Next, a method of forming a hard carbon film on a guide bush having an intermediate layer in an embodiment different from the above description will be described with reference to FIGS. This will be described with reference to FIG. FIG. 6 is a cross-sectional view illustrating a method for forming a hard carbon film according to an embodiment of the present invention. Hereinafter, a method of forming a hard carbon film on a guide bush will be described with reference to FIGS. 6 and 3 alternately.

As shown in FIG. 6, a guide bush 11 for forming a hard carbon film on the upper surface of an intermediate layer is disposed in a vacuum chamber 61 having a gas inlet 63 and an exhaust port 65. At this time, the outer peripheral tapered surface 1 of the open end surface of the guide bush 11
On the 1a side, a dummy member 53 is arranged. The dummy member 53 has a columnar shape, and has an opening having an inner diameter substantially the same as the opening size of the inner peripheral surface 11b of the guide bush 11 at the center thereof. The outer diameter of the dummy member 53 is the same as the size of the end face of the guide bush 11. That is, the dummy member 53 has a ring-shaped outer shape.

Then, the inside of the vacuum chamber 61 is evacuated from the exhaust port 65 by an exhaust means (not shown in FIG. 6) so that the degree of vacuum becomes 3 × 10 ^-5 torr or less, and then carbon is contained from the gas inlet 63. Methane gas (CH4) is introduced into the vacuum chamber 61 as a gas, and the degree of vacuum is adjusted to 0.1 torr.

The guide bush 11 has an oscillation frequency of 13.56 MHz via a matching circuit 67.
A high frequency voltage is applied from a high frequency power supply 69 having z.
Further, an auxiliary electrode 71 connected to a ground potential is arranged to be inserted in the inner surface of the opening of the guide bush 11 and at the center of the opening to generate plasma.

At this time, the plasma is applied to the guide bush 11
The hard carbon film 15 can be formed on the inner peripheral surface 11b of the guide bush 11 in the area around the auxiliary electrode 71 disposed on the inner surface of the opening.

As described above, the hard carbon film 15 is formed by the plasma-enhanced chemical vapor deposition method. In the film formation in the plasma-enhanced chemical vapor deposition method, the film can be formed with good step coverage. Therefore, the hard carbon film 15 can be formed on the inner peripheral surface 11b of the guide bush 11 so as to follow the unevenness of the surface of the intermediate layer 14, and the unevenness can be formed on the surface 15a.

As described above, in the method for forming a hard carbon film according to the embodiment of the present invention, the auxiliary electrode 71 is provided on the inner surface of the opening of the guide bush 11. Therefore, the same potential does not face each other in the inner surface area of the opening, and the hollow discharge, which is an abnormal discharge, does not occur. As a result, a uniform hard carbon film can be formed with good adhesion even on the inner surface of the opening.

As described above, since the auxiliary electrode 71 is provided on the inner surface of the opening of the guide bush 11, the potential characteristics become uniform on the inner surface of the opening of the guide bush 11 in the longitudinal direction. As a result, there is no occurrence of a film thickness distribution of the hard carbon film formed on the inner surface of the opening of the guide bush 11, and the hard carbon film can be formed with a uniform film thickness on the opening end surface and the inner side of the opening.

The auxiliary electrode 71 is connected to the guide bush 11
It is sufficient that the gap is smaller than the opening size, and a gap of about 4 mm, that is, a plasma forming region is provided. The auxiliary electrode 71 may be made of a metal material such as stainless steel.

The auxiliary electrode 71 has a circular cross section. When the auxiliary electrode 71 is inserted into the guide bush 11, the length is set so as to be aligned with the opening end face of the dummy member 53, or the length is set so that the auxiliary electrode 71 protrudes from the end face of the dummy member 53. 53 The length is configured so as not to protrude from the end face but to be 1 mm to 2 mm deep from the end face.

Further, as described above, the dummy member 53 is disposed on the open end surface of the guide bush 11. The opening size of the central portion of the dummy member 53 and the opening size of the guide bush 11 are substantially the same.

The dummy member 53 plays a role described below. That is, in the method of forming the hard carbon film shown in FIG. 6, plasma is generated on the inner surface of the guide bush 11 and the outer peripheral portion of the guide bush 11. Then, the charges are easily concentrated on the end face of the guide bush 11, and the end face area of the guide bush 11 has a higher charge than the inner face of the guide bush 11, that is, a so-called edge effect occurs. Here, the plasma intensity in the vicinity of the end face of the guide bush 11 is higher than in other regions, and is also unstable.

Furthermore, the end area of the guide bush 11
Plasma on guide bush 11 inner surface and guide bush 1
It will be affected by both plasma and the plasma at the outer periphery. When the hard carbon film is formed in such a state, several mm from the open end face of the guide bush 11
The adhesiveness of the hard carbon film is slightly inferior between the deep region and the other region, and the film quality is slightly different.

Therefore, if a hard carbon film is formed by disposing the dummy member 53 on the open end surface of the guide bush 11,
The region having the different film quality and adhesion is not formed on the inner surface of the guide bush 11, but is formed on the inner surface of the opening of the dummy member 53.

When a hard carbon film was formed using an apparatus as shown in FIG.
A region having a width of 1 mm to 2 mm and different film quality and adhesion was formed at a depth of about 7 mm from the opening end face of No. 1. Therefore, a dummy member 53 having an opening size substantially equal to the opening size of the guide bush 11 and having a length of 15 mm was disposed on the opening end face of the guide bush 11, and a film was formed under the above-described conditions for forming the hard carbon film. .

As a result, regions having different film quality and adhesion were formed on the dummy member 53, and no region having different film quality and adhesion was formed on the inner surface of the guide bush 11 at all.

[Third Example of Method of Forming Hard Carbon Film: FIGS. 7 and 3] Next, a method of forming a hard carbon film on the upper surface of the intermediate layer of the guide bush in an embodiment different from the above description will be described with reference to FIG. It will be described using FIG. FIG. 7 is a cross-sectional view illustrating a method for forming a hard carbon film according to an embodiment of the present invention. Hereinafter, a method of forming a hard carbon film on a guide bush will be described with reference to FIGS. 7 and 3 alternately.

As shown in FIG. 7, a guide bush 11 for forming a hard carbon film is arranged in a vacuum chamber 61 having a gas inlet 63 and an exhaust port 65. At this time, a dummy member 53 is arranged on the open end face of the guide bush 11. The dummy member 53 has a columnar shape, and has an opening having an inner diameter substantially the same as the opening of the inner peripheral surface 11b of the guide bush 11 at the center thereof. This dummy member 53
Has the same size as the end face of the guide bush 11.

Then, the inside of the vacuum chamber 61 is evacuated from the exhaust port 65 by exhaust means (not shown) so that the degree of vacuum is 3 × 10 ⁻⁵ torr or less. Thereafter, methane gas (CH4) as a gas containing carbon is introduced into the vacuum chamber 61 from the gas inlet 63 to adjust the degree of vacuum to 0.1 torr.

Then, a DC voltage of −600 V is applied to the guide bush 11 from the DC power supply 73.
Further, an auxiliary electrode 71 connected to the ground potential is arranged to be inserted in the inner surface of the opening of the guide bush 11 and at the center of the opening. For this reason, plasma is generated on the inner surface of the opening of the guide bush 11 in the peripheral region of the auxiliary electrode 71 to form the hard carbon film 15. At this time, the hard carbon film 15 is formed to have a thickness of 1 μm to 5 μm.

As described above, the hard carbon film 15 is formed by the plasma-enhanced chemical vapor deposition method. In the film formation in the plasma-enhanced chemical vapor deposition method, the film can be formed with good step coverage. Therefore, the hard carbon film 15 can be formed on the inner peripheral surface 11b of the guide bush 11 so as to follow the unevenness of the surface of the intermediate layer 14, and the unevenness can be formed on the surface 15a.

In the method for forming a hard carbon film according to the present invention, the auxiliary electrode 71 is disposed on the inner surface of the opening of the guide bush 11. Therefore, a hollow discharge, which is an abnormal discharge, does not occur, and a uniform hard carbon film can be formed on the inner surface of the opening of the guide bush 11 with good adhesion.

As described above, in the method for forming a hard carbon film according to the embodiment of the present invention, since the auxiliary electrode 71 is provided on the inner surface of the opening of the guide bush 11,
The potential characteristics become uniform on the inner surface of the opening in the longitudinal direction. As a result, there is no occurrence of a film thickness distribution of the hard carbon film formed on the inner surface of the opening of the guide bush 11, and a uniform film thickness can be formed between the opening end surface and the back side of the opening.

The auxiliary electrode 71 is connected to the guide bush 11
It is sufficient that the gap is smaller than the opening size, and a gap of about 4 mm, that is, a plasma forming region is provided. The auxiliary electrode 71 may be made of a metal material such as stainless steel. Further, the sectional shape of the auxiliary electrode 71 is circular. When the auxiliary electrode 71 is inserted into the guide bush 11, the length is set so as to be aligned with the opening end face of the dummy member 53, or the length is set so that the auxiliary electrode 71 protrudes from the end face of the dummy member 53. 1mm from end face without protruding from end face
It is configured to have a length such that it is ２2 mm deeper.

Further, as described above, the dummy member 53 is disposed on the open end surface of the guide bush 11. The opening size of the central portion of the dummy member 53 and the opening size of the guide bush 11 are substantially the same.

The dummy member 53 plays a role described below. That is, in the method of forming the hard carbon film shown in FIG. 7, plasma is generated on the inner surface of the guide bush 11 and the outer peripheral portion of the guide bush 11.

The end face of the guide bush 11 tends to concentrate charges, and the end face area of the guide bush 11 has a higher charge than the inner surface of the guide bush 11, that is, a so-called edge effect occurs. Here, the plasma intensity in the vicinity of the end face of the guide bush 11 is higher than in other regions, and is also unstable. Further, the end region of the guide bush 11 is affected by both the plasma on the inner surface of the guide bush 11 and the plasma on the outer peripheral portion of the guide bush 11.

When the hard carbon film is formed in such a state, a few mm from the open end face of the guide bush 11
The adhesiveness of the hard carbon film is slightly inferior between the deep region and the other region, and the film quality is slightly different.

Accordingly, if a hard carbon film is formed by disposing the dummy member 53 on the open end surface of the guide bush 11,
The region having the different film quality and adhesion is not formed on the inner surface of the guide bush 11, but is formed on the inner surface of the opening of the dummy member 53.

When a hard carbon film was formed using an apparatus as shown in FIG.
A region having a width of 1 mm to 2 mm and different film quality and adhesion was formed at a depth of about 7 mm from the opening end face of No. 1.

Therefore, a dummy member 53 having an opening dimension substantially equal to the opening dimension of the guide bush 11 and a length dimension of 15 mm is arranged on the opening end face of the guide bush 11, and a film is formed under the conditions for forming the hard carbon film described above. Was done. As a result, regions having different film qualities and adhesion were formed on the dummy member 53, and no regions having different film qualities and adhesion were formed on the inner surface of the guide bush 11 at all.

[Fourth Example of Method of Forming Hard Carbon Film: FIGS. 10 and 3] Next, a method of forming a hard carbon film in an embodiment different from the above description will be described. FIG. 10 is a cross-sectional view illustrating a method for forming a hard carbon film according to an embodiment of the present invention. Hereinafter, a method of forming a hard carbon film on a guide bush will be described with reference to FIG. 10 and FIG. 3 showing the guide bush.

As shown in FIG. 10, a guide bush 11 for forming a hard carbon film is disposed in a vacuum chamber 61 having a gas inlet 63 and an exhaust port 65. At this time, a dummy member 53 is arranged on the outer peripheral tapered surface 11a side of the opening end surface of the guide bush 11. The dummy member 53 has a cylindrical shape, and the center thereof has an inner peripheral surface 1 of the guide bush 11.
An opening having an inside diameter substantially equal to the opening size of 1b is provided. Further, the outer dimensions of the dummy member 53 are
The size is the same as the size of the end face.

An auxiliary electrode 71 connected to the DC positive potential from the auxiliary electrode power supply 83 is provided on the inner surface of the opening of the guide bush 11. At this time, the auxiliary electrode 71 is arranged so as to be at the center of the opening of the guide bush 11.

Then, the inside of the vacuum chamber 61 is set to a degree of vacuum of 3 × 10
Vacuum is exhausted from the exhaust port 65 to a pressure of ^-5 torr or less by an exhaust means (not shown). Thereafter, benzene is introduced into the vacuum chamber 61 as a gas containing carbon from the gas inlet 63, and the pressure in the vacuum chamber 61 is increased to 5 × 10 ⁻³ torr.
Control so that

The guide bush 11 has a DC power source 7
3, a DC voltage is applied to the anode 79 from the anode power supply 75, and a filament 81 is applied to the anode 79.
, An AC voltage is applied from a filament power supply 77. Further, a DC positive voltage is applied to the auxiliary electrode 71 from the auxiliary electrode power supply 83.

At this time, DC +20 V is applied to the auxiliary electrode 71 from the auxiliary electrode power supply 83. Further, a DC voltage applied from the DC power supply 73 to the guide bush 11 is −3 kV, and a DC voltage applied from the anode power supply 75 to the anode 79 is +10 V. Further, the voltage applied from the filament power supply 77 to the filament 81 is adjusted so that a current of 30 A flows.
V AC voltage is applied.

The hard carbon film 15 is formed on the inner peripheral surface 11b of the guide bush 11 by generating plasma in the peripheral region of the auxiliary electrode 71 disposed on the inner surface of the opening of the guide bush 11 in the vacuum chamber 61. The hard carbon film 15 formed on the inner peripheral surface 11b of the guide bush 11 has a thickness of 1 μm.
A film is formed from m to 5 μm.

As described above, the hard carbon film 15 is formed by the plasma-enhanced chemical vapor deposition method, and in the film formation in the plasma-enhanced chemical vapor deposition method, the film can be formed with good step coverage. Therefore, the hard carbon film 15 can be formed on the inner peripheral surface 11b of the guide bush 11 so as to follow the unevenness of the surface of the intermediate layer 14, and the unevenness can be formed on the surface 15a.

FIG. 13 is a graph showing the relationship between the DC positive voltage applied to the auxiliary electrode 71 using the auxiliary electrode power supply 83 and the thickness of the hard carbon film formed on the inner surface of the guide bush opening. In the graph of FIG. 13, the DC positive voltage applied to the auxiliary electrode 71 is changed from zero V to 30 V,
Further, the thickness of the hard carbon film when the gap between the inner surface of the opening of the guide bush 11 and the auxiliary electrode 71 is 3 mm and 5 mm is shown. Note that the curve 88 is the guide bush 11
The curve 91 shows the characteristics when the gap between the inner surface of the opening and the auxiliary electrode 71 is 3 mm, and the curve 91 shows the characteristics when the gap between the inner surface of the opening of the guide bush 11 and the auxiliary electrode 71 is 5 mm.

As shown by curves 88 and 91 in FIG. 13, when the DC positive voltage applied from the auxiliary electrode power supply 83 to the auxiliary electrode 71 is increased, the film forming speed of the hard carbon film is improved. Furthermore, the larger the gap size between the inner surface of the opening of the guide bush 11 and the auxiliary electrode 71, the higher the film forming speed of the hard carbon film.

A curve 88, that is, the gap between the inner surface of the opening of the guide bush 11 and the auxiliary electrode 71 is 3 m.
In the case of m, with a ground voltage of zero V applied to the auxiliary electrode 71, no plasma is generated on the inner surface of the opening of the guide bush 23, and a hard carbon film cannot be formed.

However, even when the gap between the inner surface of the opening of the guide bush 11 and the auxiliary electrode 71 is 3 mm, if the DC positive voltage from the auxiliary electrode power supply 83 applied to the auxiliary electrode 71 is increased, the auxiliary electrode 71 Plasma is generated on the inner surface of the surrounding opening, and a hard carbon film can be formed.

In the method of forming a hard carbon film shown in FIG. 10, the outer peripheral portion of the guide bush 11 is arranged so as to be inserted into the inner surface of the opening of the guide bush 11 and is further provided with an auxiliary electrode 71 for applying a DC positive voltage. In addition, plasma can be formed also on the inner surface of the guide bush 11 opening. The auxiliary electrode 71 which is arranged to be inserted into the inner surface of the opening of the guide bush 11 and is connected to the DC positive voltage prevents the same potential from being opposed to the inner surface of the opening. Therefore, there is no occurrence of hollow discharge, which is abnormal discharge, and the adhesion of the hard carbon film is improved.

Further, the potential characteristics of the inner surface of the guide bush 11 in the longitudinal direction of the opening are made uniform by the auxiliary electrode 71 disposed in the opening, and there is no thickness distribution of the hard carbon film formed on the inner surface of the opening. A uniform film thickness can be formed between the end face and the back side of the opening.

Further, in the embodiment of the method for forming a hard carbon film of the present invention, the auxiliary electrode 71 provided at the center of the inner surface of the opening of the guide bush 11 is connected to the auxiliary electrode power supply 8.
The hard carbon film is formed by applying a DC positive voltage from Step 3. Therefore, the auxiliary electrode 71 for applying a DC positive voltage
The effect of collecting electrons in the surrounding area of the auxiliary electrode 7 is generated.
The surrounding area of 1 has a higher electron density.

When the electron density is increased as described above, the probability of collision between electrons and gas molecules containing carbon is inevitably increased, ionization of gas molecules is promoted, and the plasma intensity in the inner surface area of the opening of the guide bush 11 is increased. Become. Therefore, in the method for forming a hard carbon film of the present invention in which a DC positive voltage is applied to the auxiliary electrode 71, the film formation speed of the hard carbon film is compared with the case where no DC positive voltage is applied to the auxiliary electrode 71. Get higher.

Further, when the opening size of the guide bush 11 becomes smaller and the gap size between the inner surface of the opening and the auxiliary electrode 71 becomes smaller, if a hard carbon film is formed without applying a DC positive voltage to the auxiliary electrode 71, Does not generate plasma and cannot form a film.

On the other hand, in the method for forming a hard carbon film according to the present invention, since a DC positive voltage from the auxiliary electrode power supply 83 is applied to the auxiliary electrode 71 disposed on the inner surface of the opening of the guide bush 11, electrons are forcibly applied. Auxiliary electrode 7
Plasma can be generated around the auxiliary electrode 71 by being collected on the inner surface of the opening in the surrounding area of the first electrode. Therefore, even if the guide bush 11 having a small opening size cannot be formed by the formation of the hard carbon film using the auxiliary electrode to which no DC positive voltage is applied, the auxiliary electrode 71 to which the DC positive voltage is applied from the auxiliary electrode power supply 83 is also provided. By applying the method for forming a hard carbon film of the present invention using the method, a film can be formed.

Further, when the auxiliary electrode 71 is inserted into the opening of the guide bush 11, the auxiliary electrode 71 is disposed so that the front end of the auxiliary electrode 71 is located inside the opening end surface of the dummy member 53. It is configured not to be exposed from the end face. In the embodiment of the present invention, the length of the tip of the auxiliary electrode 71 is set so that the tip of the auxiliary electrode 71 is located 1 mm inside the opening end face of the dummy member 53.

As described above, in the method for forming a hard carbon film of the present invention, the tip of the auxiliary electrode 71 is connected to the dummy member 5.
3 are arranged inside the opening end face. For this reason, abnormal discharge of the tip of the auxiliary electrode 71, which occurs when the tip of the auxiliary electrode 71 is exposed from the opening end face of the dummy member 53, can be suppressed. 11 can be formed.

[Fifth Example of Method of Forming Hard Carbon Film: FIGS. 11 and 3] Next, a method of forming a hard carbon film on the upper surface of the intermediate layer in an embodiment different from the above description will be described. FIG. 11 is a cross-sectional view illustrating a method for forming a hard carbon film according to an embodiment of the present invention. Hereinafter, a method of forming a hard carbon film according to an embodiment of the present invention will be described with reference to FIG. 11 and FIG. 3 showing a guide bush.

As shown in FIG. 11, a guide bush 11 for forming a hard carbon film is disposed in a vacuum chamber 61 having a gas inlet 63 and an exhaust port 65. At this time, on the outer peripheral tapered surface 11a side of the open end surface of the guide bush 11,
The dummy member 53 is arranged. The dummy member 53 has a columnar shape, and an opening having an inner diameter substantially equal to the opening size of the inner peripheral surface 11b of the guide bush 11 is provided at the center thereof.
Further, the outer dimension of the dummy member 53 is the same as the size of the end face of the guide bush 11.

Then, the inside of the vacuum chamber 61 is evacuated from the exhaust port 65 to a degree of vacuum of 3 × 10 ⁻⁵ torr by an exhaust means not shown.
After evacuation as described below, methane gas was introduced into the vacuum chamber 61 as a gas containing carbon from the gas inlet 63,
Adjust the degree of vacuum to 0.1 torr. The guide bush 11 is connected to the guide bush 11 via the matching circuit 67.
A high-frequency voltage of 400 W is applied from a high-frequency power supply 69 having an oscillation frequency of 3.56 MHz.

Further, on the inner surface of the opening of the guide bush 11,
In addition, an auxiliary electrode 71 for connecting a DC positive voltage applied from an auxiliary electrode power supply 83 is inserted in the center of the opening, and plasma is applied to a region around the auxiliary electrode 71 arranged on the inner surface of the opening of the guide bush 11. The hard carbon film 15 is formed on the inner peripheral surface 11b of the guide bush 11 by the generation. The hard carbon film 15 formed on the inner peripheral surface 11b of the guide bush 11 is formed with a film thickness of 1 μm to 5 μm.

As described above, the hard carbon film 15 is formed by the plasma-enhanced chemical vapor deposition method, and in the film formation by the plasma-enhanced chemical vapor deposition method, the film can be formed with good step coverage. Therefore, the hard carbon film 15 can be formed on the inner peripheral surface 11b of the guide bush 11 so as to follow the unevenness of the surface of the intermediate layer 14, and the unevenness can be formed on the surface 15a.

At this time, the DC positive voltage applied to the auxiliary electrode 71 using the auxiliary electrode power supply 83 and the guide bush 11
The relationship with the thickness of the hard carbon film 15 formed on the inner surface of the opening is shown in the graph of FIG.

In the graph of FIG. 13, the DC positive voltage applied to the auxiliary electrode 71 is changed from zero volts to 30 volts by using the auxiliary electrode power supply 83, and furthermore, the gap between the inner surface of the opening of the guide bush 11 and the auxiliary electrode 71 is changed. The gap size is 3mm and 5m
The thickness of the hard carbon film when m is shown. Note that the curve 88
Shows the characteristic when the gap between the inner surface of the opening of the guide bush 11 and the auxiliary electrode 71 is 3 mm, and the curve 91 shows the characteristic when the gap between the inner surface of the opening of the guide bush 11 and the auxiliary electrode 71 is 5 mm. Show.

As shown by the curves 88 and 91 in FIG. 13, when the DC positive voltage applied to the auxiliary electrode 71 from the auxiliary electrode power supply 83 is increased, the film formation speed of the hard carbon film is improved. Furthermore, the larger the gap size between the inner surface of the opening of the guide bush 11 and the auxiliary electrode 71, the higher the film forming speed of the hard carbon film.

A curve 88, that is, the gap between the inner surface of the opening of the guide bush 11 and the auxiliary electrode 71 is 3 m.
In the case of m, when the voltage applied to the auxiliary electrode 71 is the ground potential of zero V, no plasma is generated on the inner surface of the opening of the guide bush 23, and a hard carbon film cannot be formed. However, even when the gap between the inner surface of the opening of the guide bush 11 and the auxiliary electrode 71 is 3 mm, if the DC positive voltage applied to the auxiliary electrode 71 using the auxiliary electrode power supply 83 is increased, the area around the auxiliary electrode 71 is increased. Plasma is generated on the inner surface of the opening, and a hard carbon film can be formed.

In the method for forming a hard carbon film shown in FIG. 11, the guide bush 11 is arranged so as to be inserted into the inner surface of the opening of the guide bush 11, and the auxiliary electrode 71 to which a DC positive voltage is applied from the auxiliary electrode power supply 83 is used. 11
The plasma can be formed not only on the outer peripheral portion but also on the inner surface of the opening of the guide bush 11.

Auxiliary electrode 71 arranged to be inserted into the inner surface of the opening of guide bush 11 and connected to a DC positive voltage
Thereby, the same potential does not face each other on the inner surface of the opening. Therefore, there is no occurrence of hollow discharge, which is abnormal discharge, and the adhesion of the hard carbon film is improved.

Further, the auxiliary electrode 71 arranged in the opening makes the potential characteristics uniform on the inner surface of the opening in the longitudinal direction of the guide bush 11, and there is no thickness distribution of the hard carbon film formed on the inner surface of the opening. A uniform film thickness can be formed between the opening and the back side of the opening.

Further, in the embodiment of the method for forming a hard carbon film of the present invention, the auxiliary electrode 71 provided at the center of the inner surface of the opening of the guide bush 11 is connected to the auxiliary electrode power supply 8.
The hard carbon film is formed by applying a DC positive voltage from Step 3. Therefore, the auxiliary electrode 71 for applying a DC positive voltage
The effect of collecting electrons in the surrounding area of the auxiliary electrode 7 is generated.
The surrounding area of 1 has a higher electron density.

When the electron density is increased as described above, the probability of collision between the gas molecules containing carbon and the electrons is inevitably increased, ionization of the gas molecules is promoted, and the plasma intensity in the inner surface area of the opening of the guide bush 11 is increased. Become. Therefore, in the method for forming a hard carbon film of the present invention in which a DC positive voltage is applied to the auxiliary electrode 71, the film formation speed of the hard carbon film is compared with the case where no DC positive voltage is applied to the auxiliary electrode 71. Get higher.

Further, when the opening size of the guide bush 11 becomes smaller and the gap between the inner surface of the opening and the auxiliary electrode 71 becomes smaller, if a hard carbon film is formed without applying a DC positive voltage to the auxiliary electrode 71, the inner surface of the opening becomes No plasma is generated and a film cannot be formed. On the other hand, in the method for forming a hard carbon film of the present invention shown in FIG. 11, a DC positive voltage is applied to the auxiliary electrode 71 disposed on the inner surface of the opening of the guide bush 11 to force electrons to form an opening in the peripheral region of the auxiliary electrode 71. Since it is collected on the inner surface, plasma can be generated around the auxiliary electrode 71.

Therefore, the guide bush 11 having a small opening cannot be formed by forming a hard carbon film using an auxiliary electrode to which no DC positive voltage is applied. Electrode 71
By applying the method for forming a hard carbon film of the present invention using the method, a film can be formed.

Further, when the auxiliary electrode 71 is inserted into the opening of the guide bush 11, the auxiliary electrode 71 is disposed so that the front end of the auxiliary electrode 71 is located inside the opening end surface of the dummy member 53. It is configured not to be exposed from the end face. In the embodiment of the present invention, the length of the tip of the auxiliary electrode 71 is set so that the tip of the auxiliary electrode 71 is located 1 mm inside the opening end face of the dummy member 53.

As described above, in the method of forming a hard carbon film according to the present invention, the tip of the auxiliary electrode 71 is
3 are arranged inside the opening end face. For this reason, abnormal discharge of the tip of the auxiliary electrode 71, which occurs when the tip of the auxiliary electrode 71 is exposed from the opening end face of the dummy member 53, can be suppressed. 11 can be formed.

[Sixth Example of Method for Forming Hard Carbon Film: FIGS. 12 and 3] Next, a method of forming a hard carbon film on the upper surface of the intermediate layer in an embodiment different from the above description will be described. FIG. 12 is a cross-sectional view illustrating a method for forming a hard carbon film according to an embodiment of the present invention. Hereinafter, a method of forming a hard carbon film will be described with reference to FIG. 12 and FIG. 3 showing a guide bush alternately.

As shown in FIG. 12, a guide bush 11 for forming a hard carbon film is disposed in a vacuum chamber 61 having a gas inlet 63 and an exhaust port 65. At this time, on the outer peripheral tapered surface 11a side of the open end surface of the guide bush 11,
The dummy member 53 is arranged. The dummy member 53 has a columnar shape, and an opening having an inner diameter substantially equal to the opening size of the inner peripheral surface 11b of the guide bush 11 is provided at the center thereof.
Further, the outer dimension of the dummy member 53 is the same as the size of the end face of the guide bush 11.

The inside of the vacuum chamber 61 is evacuated from the exhaust port 65 to a degree of vacuum of 3 × 10 ⁻⁵ torr by an exhaust means (not shown).
After evacuation as described below, methane gas was introduced into the vacuum chamber 61 as a gas containing carbon from the gas inlet 63,
Adjust the degree of vacuum to 0.1 torr. Thereafter, a DC voltage of −600 V is applied to the guide bush 11 from the DC power supply 73.

Further, on the inner surface of the opening of the guide bush 11,
In addition, an auxiliary electrode 71 connected to the DC positive voltage applied from the auxiliary electrode power supply 83 is inserted in the center of the opening, and plasma is generated in a region around the auxiliary electrode 71 arranged on the inner surface of the opening of the guide bush 11. Thus, the hard carbon film 15 is formed on the inner peripheral surface 11b of the guide bush 11. The hard carbon film 15 formed on the inner peripheral surface 11b of the guide bush 11 is formed with a film thickness of 1 μm to 5 μm.

As described above, the hard carbon film 15 is formed by the plasma-enhanced chemical vapor deposition method, and in the film formation in the plasma-enhanced chemical vapor deposition method, the film can be formed with good step coverage. Therefore, the hard carbon film 15 can be formed on the inner peripheral surface 11b of the guide bush 11 so as to follow the unevenness of the surface of the intermediate layer 14, and the unevenness can be formed on the surface 15a.

At this time, the DC positive voltage applied to the auxiliary electrode 71 using the auxiliary electrode power supply 83 and the guide bush 11
The relationship with the thickness of the hard carbon film formed on the inner surface of the opening is shown in the graph of FIG.

In the graph of FIG. 13, the DC positive voltage applied to the auxiliary electrode 71 is changed from zero volts to 30 volts by using the auxiliary electrode power supply 83, and furthermore, the gap between the inner surface of the opening of the guide bush 11 and the auxiliary electrode 71 is changed. The gap size is 3mm and 5m
The thickness of the hard carbon film when m is shown. Note that curve 8
8 shows the characteristics when the gap between the inner surface of the opening of the guide bush 11 and the auxiliary electrode 71 is 3 mm, and the curve 91 shows the characteristics when the gap between the inner surface of the opening of the guide bush 11 and the auxiliary electrode 71 is 5 mm. Is shown.

As shown by the curves 88 and 91 in FIG. 14, when the DC positive voltage applied from the auxiliary electrode power supply 83 to the auxiliary electrode 71 is increased, the film forming speed of the hard carbon film is improved. Furthermore, the larger the gap size between the inner surface of the opening of the guide bush 11 and the auxiliary electrode 71, the higher the film forming speed of the hard carbon film.

The curve 88, that is, the gap between the inner surface of the opening of the guide bush 11 and the auxiliary electrode 71 is 3 m.
In the case of m, if the voltage applied to the auxiliary electrode 71 is a ground potential of zero V, no plasma is generated on the inner surface of the opening of the guide bush 11 and a hard carbon film cannot be formed. However, even when the gap between the inner surface of the opening of the guide bush 11 and the auxiliary electrode 71 is 3 mm, as the DC positive voltage from the auxiliary electrode power supply 83 applied to the auxiliary electrode 71 is increased, the opening around the auxiliary electrode 71 is increased. Plasma is generated on the inner surface, and a hard carbon film can be formed.

In the method of forming a hard carbon film shown in FIG. 12, the guide bush 11 is provided so as to be inserted into the inner surface of the opening of the guide bush 11, and the auxiliary electrode 71 to which a DC positive voltage is applied from the auxiliary electrode power supply 83. The plasma can be formed not only on the outer peripheral portion but also on the inner surface of the opening of the guide bush 11.

An auxiliary electrode 71 arranged to be inserted into the inner surface of the opening of the guide bush 11 and connected to a positive DC voltage
Thereby, the same potential does not face each other in the inner surface area of the opening. Therefore, there is no occurrence of hollow discharge, which is abnormal discharge, and the adhesion of the hard carbon film is improved.

Further, the auxiliary electrode 71 disposed in the opening makes the electric potential characteristics uniform on the inner surface of the opening in the longitudinal direction of the guide bush 11, and the thickness distribution of the hard carbon film formed on the inner surface of the opening does not occur. A uniform film thickness can be formed between the end face and the back side of the opening.

Further, in the embodiment of the method for forming a hard carbon film of the present invention, the auxiliary electrode 71 provided at the center of the inner surface of the opening of the guide bush 11 is connected to the auxiliary electrode power supply 8.
The hard carbon film is formed by applying a DC positive voltage from Step 3. Therefore, the auxiliary electrode 71 for applying a DC positive voltage
The effect of collecting electrons in the surrounding area of the auxiliary electrode 7 is generated.
The surrounding area of 1 has a higher electron density.

When the electron density is increased as described above, the probability of collision between the gas molecules containing carbon and the electrons is inevitably increased, ionization of the gas molecules is promoted, and the plasma intensity in the inner surface area of the opening of the guide bush 11 is increased. Become. Therefore, in the method for forming a hard carbon film of the present invention in which a DC positive voltage is applied to the auxiliary electrode 71, the film formation speed of the hard carbon film is compared with the case where no DC positive voltage is applied to the auxiliary electrode 71. Get higher.

Further, when the opening dimension of the guide bush 11 is reduced and the gap dimension between the inner surface of the opening and the auxiliary electrode 71 is reduced, if a hard carbon film is formed without applying a DC positive voltage to the auxiliary electrode 71, Does not generate plasma and cannot form a film.

On the other hand, in the method for forming a hard carbon film according to the present invention, a DC positive voltage is applied to the auxiliary electrode 71 disposed on the inner surface of the opening of the guide bush 11 using the auxiliary electrode power supply 83 to forcibly remove electrons. Since the light is collected on the inner surface of the opening around the auxiliary electrode 71, plasma can be generated around the auxiliary electrode 71.

Therefore, a DC positive voltage from the auxiliary electrode power supply 83 is applied to the guide bush 11 having a small opening size, which cannot be formed by forming a hard carbon film using an auxiliary electrode to which no DC positive voltage is applied. Auxiliary electrode 7
By applying the method for forming a hard carbon film of the present invention using No. 1, a film can be formed.

Further, when the auxiliary electrode 71 is inserted into the opening of the guide bush 11, the auxiliary electrode 71 is disposed so that the front end of the auxiliary electrode 71 is located inside the opening end surface of the dummy member 53. It is configured not to be exposed from the end face. In the embodiment of the present invention, the length of the tip of the auxiliary electrode 71 is set so that the tip of the auxiliary electrode 71 is located 1 mm inside the opening end face of the dummy member 53.

As described above, in the method for forming a hard carbon film of the present invention, the tip of the auxiliary electrode 71 is
3 are arranged inside the opening end face. For this reason, abnormal discharge of the tip of the auxiliary electrode 71, which occurs when the tip of the auxiliary electrode 71 is exposed from the opening end face of the dummy member 53, can be suppressed. 11 can be formed.

[Second Example of Guide Bush Structure: FIG. 2] Next, the structure of a guide bush in an embodiment different from the above description will be described with reference to FIG. FIG. 2 is an enlarged sectional view showing an inner peripheral surface of a guide bush according to another embodiment of the present invention.

As shown in FIG. 2, the inner surface 11b of the guide bush 11 (see FIG. 3) is
The hard carbon film 15 is provided on a surface that comes into contact with the first intermediate layer 14a, the second intermediate layer 14b, and the workpiece 51.

The guide bush 11 according to the present invention, which is provided on a guide bush device of an automatic lathe and rotatably supports the workpiece 51, has a first intermediate layer 14a and a second intermediate layer 14a provided on its inner peripheral surface 11b. When the hard carbon film 15 is provided via the layer 14b, a configuration is adopted in which the surface 15a of the hard carbon film 15 that is in contact with the workpiece 51 has irregularities. Alternatively, in the guide bush 11 of the present invention, the super hard member 12 is provided on the inner peripheral surface 11b, and the first intermediate layer 14a and the second intermediate layer 14a formed on the upper surface of the super hard member 12 are provided.
When the hard carbon film 15 is provided via the intermediate layer 14b, the surface 15a of the hard carbon film 15 that is in contact with the workpiece 51 is made uneven.

When the surface 15a of the hard carbon film 15 that is in contact with the workpiece 51 is made uneven, the hard carbon film 15 and the workpiece are harder than the conventional hard carbon film that does not have an uneven surface. The area of contact with 51 can be reduced. Therefore, it is possible to further promote the low friction characteristics, which are the excellent characteristics of the hard carbon film 15.

As a result, the inner peripheral surface 1 of the guide bush 11
1b, the contact resistance between the workpiece 51 rotating in the axial direction and the hard carbon film 15 is reduced.
5 can be suppressed. Therefore, in the guide bush 11 of the present invention, the durability of the hard carbon film 15 formed on the inner peripheral surface 11b can be improved, and the reliability of the guide bush 11 for long-term use can be improved.

The surface of the surface of the super hard member 12 which comes into contact with the intermediate layer 14 selectively removes cobalt (Co) functioning as a binder of the super hard member 12.
That is, the cemented carbide member 1 from which the cobalt (Co) has been removed.
2. A hard carbon film 15 is provided on the upper surface with an intermediate layer 14 interposed therebetween.

As a result, the hard carbon film 15 of the present invention can be formed with good adhesion on the inner peripheral surface 11b of the guide bush 11, and the problem of peeling does not occur. Therefore, the service life of the guide bush 11 can be greatly extended as compared with the conventional art, and the reliability for long-term use can be improved.

The inventors believe that the superior features of the guide bush 11 of the present invention have been obtained for the following reasons. The surface state before and after removing cobalt on the surface of the superhard member 12 in contact with the first intermediate layer 14a was observed with a scanning electron microscope (SEM).

On the surface of the super-hard member 12 before removing cobalt, a trace of polishing the inner peripheral surface of the super-hard member 12 was observed. On the other hand, no machining marks were observed on the surface of the superhard member 12 from which cobalt had been removed.

When the surface of the super hard member 12 was observed with the naked eye, the difference was obvious. That is, the super hard member 12
The surface of the superhard member 12 from which cobalt had been removed was in a mirror-finished state instead of a mirror-finished surface, whereas the surface before removing cobalt was in a mirror-finished state.

When the cobalt on the surface of the cemented carbide member 12 that comes into contact with the first intermediate layer 14a is removed, the cobalt functions as a binder. The carbon also peeled off, and as described above, no processing marks were observed, and the material was in a satin state.

As described above, since the processing marks on the surface of the cemented carbide member 12 in contact with the first intermediate layer 14a disappear and are not observed, and because of the matte state, the adhesion of the hard carbon film 15 is further improved. Is improved. In particular, regarding processing marks, the first intermediate layer 14a formed at the processing mark location
Believes that a film stress such as elongation or compression has occurred at that location, and that the film stress has caused poor adhesion of the first intermediate layer 14a. In addition, the phenomenon that the adhesiveness is deteriorated due to the film stress does not occur. As a result, in the guide bush 11 of the present invention, the phenomenon that the intermediate layer 14 peels does not occur, and therefore, the adhesion of the hard carbon film 15 formed on the upper surface of the intermediate layer 14 is also improved, and The service life can be greatly extended as compared with the prior art, and the reliability for long-term use is improved.

The hard carbon film 15 is a black film and has properties very similar to diamond. That is, the hard carbon film 15 has excellent characteristics such as high mechanical hardness, low coefficient of friction, good electrical insulation, high thermal conductivity, and high corrosion resistance. For this reason, the guide bush 11 of the present invention can suppress wear of the inner peripheral surface in contact with the workpiece 51 in heavy cutting in which the cutting amount is large and the processing speed is large, and the generation of scratches on the workpiece is reduced. And the guide bush 11 and the workpiece 51
Can be suppressed from occurring.

Further, in the guide bush 11 of the present invention, a superhard member 12 having high hardness is formed below the intermediate layer 14 on the inner peripheral surface 11b, and a hard carbon film 15 is provided.
When the superhard member 12 having high hardness is provided below the hard carbon film 15, local peeling or wear of the hard carbon film 15 can be suppressed, and the reliability of the guide bush 11 for long-term use can be further improved. Can be further improved.

Further, the present invention employs a structure in which a first intermediate layer 14a and a second intermediate layer 14b are provided between the super hard member 12 and the hard carbon film 15. And, as the first intermediate layer 14a, titanium (Ti) or chromium (Cr) is applied, and as the second intermediate layer 14b, a silicon film (Si) or germanium (Ge) is applied. Here, the first intermediate layer 14a has a role of ensuring a sufficient adhesive force with the underlying superhard member 12,
These coatings are excellent in adhesion to the superhard member 12,
Further, since the second intermediate layer 14b is made of a material that is an element of Group IVb of the periodic table as described above, the hard carbon film 1 made of carbon of the same Group IV element is used as the material.
5 and shows high adhesiveness.

As described above, when the intermediate layer 12 is interposed between the super hard member 12 and the hard carbon film 15, the adhesion of the hard carbon film 15 becomes high. Further, the intermediate layer 14
Also has the following effect. That is, the intermediate layer 14 suppresses the phenomenon that cobalt contained as a binder in the superhard member 12 is dissolved in the carbon of the hard carbon film 15.

That is, the phenomenon that cobalt contained as a binder in the superhard member 12 reacts with carbon in the hard carbon film 15 does not occur. For this reason, the hard carbon film 15 can be formed on the inner peripheral surface of the guide bush 11 with good adhesion 11b, and as a result, the peeling phenomenon of the hard carbon film 15 on the inner peripheral surface of the guide bush does not occur.

In the method of forming a film for obtaining the structure shown in FIG. 2, the first intermediate layer 14a is formed by forming titanium or chromium by the method described with reference to FIG.
The target 55 may be changed to silicon or germanium, and other conditions may be used to form a film under the same conditions as when forming the first intermediate layer 14a. Further, as the method of forming the film of the hard carbon film 15 formed on the upper surface of the second intermediate layer 14b, the method of forming the film described with reference to FIGS. 5 to 7 and FIGS. Is omitted.

As the second intermediate layer 14b, an alloy material film containing carbon such as a silicon carbide film (SiC) or a tungsten carbide (WC) film instead of silicon or germanium can be applied. The silicon carbide film and the tungsten carbide film also have substantially the same function as the silicon film and the germanium film, and
4b has almost the same effect as when a silicon film or a germanium film is used. The silicon carbide film and the tungsten carbide film may be formed by using the apparatus shown in FIG.

In the embodiment of the present invention described above, an example has been described in which the intermediate layer 14 and the hard carbon film 15 are formed on the inner peripheral surface 11b of the guide bush 11 via the super hard member 12. However, depending on the application, this super hard member 12
Some guide bushes 11 are not formed. In such a guide bush 11, the intermediate layer 14 and the hard carbon film 15 may be directly formed on the inner peripheral surface 11b.

In the embodiment of the present invention described above, an example in which the intermediate layer 14 and the hard carbon film 15 are sequentially formed on the super hard member 12 has been described. However, instead of the super hard member 12, a carburized layer, which is one of the surface hardening methods, may be formed on the inner peripheral surface 11b of the guide bush 11.

FIGS. 5 to 7 and FIGS. 10 to 1
In the description of the embodiment of the method for forming a hard carbon film of the present invention described with reference to No. 3, the embodiment using methane gas or benzene gas as the gas containing carbon has been described, but it contains carbon such as ethylene in addition to methane. Evaporation vapor of a gas or a liquid containing carbon such as hexane can also be used.

In the film formation of the embodiment described with reference to FIG. 4, the guide bush 11 may be rotated, and the guide bush 11 may be arranged at a certain angle from a perpendicular to the surface of the target 55 to form the film. You may.

Further, FIG. 4, FIG. 5, FIG. 6, FIG. 7, FIG.
In the method of forming a coating film according to the embodiment described with reference to FIGS. 11 and 12, the coating film of the intermediate layer and the hard carbon film is formed on the outer peripheral portion of the guide bush 11 and the inner surface of the opening. A hard carbon film or a coating of an intermediate layer can be formed only on the inner surface. In that case, a method of arranging a covering member on the outer peripheral portion of the guide bush 11 so as to cover the outer peripheral portion of the guide bush 11 or simply forming an aluminum foil around the outer peripheral portion of the guide bush 11 may be employed. Good.

FIGS. 5 to 7 and FIGS. 10 to 1
In the method for forming a hard carbon film in the embodiment described using No. 2, the embodiment has been described in which the dummy member 53 is disposed on the open end surface of the guide bush 11 to form a film. However, if the quality of the hard carbon film in the region near the opening end face is not so different from the other regions,
A film can be formed without disposing the dummy member 53 on the open end surface of the guide bush 11.

[0249]

As is apparent from the above description, the guide bush of the present invention, which is provided on the guide bush device of an automatic lathe and rotatably supports a workpiece, is provided with an intermediate layer provided on the inner peripheral surface thereof. When the hard carbon film is provided, a configuration is employed in which the surface of the hard carbon film that comes into contact with the workpiece is made uneven. Alternatively, the guide bush of the present invention is provided with a super hard member on the inner peripheral surface thereof, and when a hard carbon film is provided via an intermediate layer formed on the upper surface of the super hard member, a hard carbon film which is in contact with a workpiece is formed. A configuration in which the surface is uneven is adopted.

When the surface of the hard carbon film in contact with the workpiece is made uneven, the contact area between the hard carbon film and the workpiece is larger than that of the conventional hard carbon film having no uneven surface. Can be reduced. Therefore, it is an excellent characteristic of the hard carbon film,
It is possible to further promote low friction characteristics.

Further, the oil supplied between the inner peripheral surface of the guide bush and the workpiece can be held in the concave portion of the hard carbon film having the surface irregularities. As a result, the contact resistance between the workpiece rotating on the inner peripheral surface of the guide bush and sliding in the axial direction and the hard carbon film is reduced, and wear of the hard carbon film can be suppressed. Therefore, in the guide bush of the present invention, the durability of the hard carbon film formed on the inner peripheral surface can be improved, and the reliability of the guide bush for long-term use can be improved.

Further, according to the n-type guide bush of the present invention, the cobalt (C) on the surface in contact with the intermediate layer of the cemented carbide member composed of tungsten (W), carbon (C) and cobalt (Co)
o) is adopted. Then, a hard carbon film is provided on the upper surface of the super hard member from which cobalt (Co) has been removed, via an intermediate layer.

As described above, in the guide bush of the present invention, the intermediate layer is provided on the upper surface of the super hard member from which cobalt (Co) has been removed, and the hard carbon film is further formed thereon. Therefore, the hard carbon film of the present invention can be formed with good adhesion on the inner peripheral surface of the guide bush, and the problem of peeling does not occur. Therefore, the service life of the guide bush can be significantly extended,
It is possible to improve reliability for long-term use.

The inventors believe that these effects are obtained for the reasons described below. The surface states before and after removing cobalt on the surface of the superhard member in contact with the intermediate layer were observed with a scanning electron microscope (SEM).

On the surface of the cemented carbide member before removal of cobalt, a trace of polishing the inner peripheral surface of the cemented carbide member was observed. On the other hand, no machining mark was observed on the surface of the cemented carbide member after removing cobalt.

Further, even when the surface of the superhard member was observed with the naked eye, the difference was obvious. That is, the surface of the cemented carbide member before removing cobalt had a polished surface in a mirror-like state, whereas the surface of the cemented carbide member after removing cobalt had a mirror-finished state instead of a mirror-like surface.

When the cobalt on the surface of the cemented carbide member in contact with the intermediate layer was removed, the cobalt functioned as a binder, so that tungsten and carbon bonded to the binder by the sintering process also peeled off. As described above, no processing marks are observed, and the surface is in a satin state.

As described above, since the machining marks on the surface of the cemented carbide member in contact with the intermediate layer disappear and are not observed, and because of the matte state, the adhesion of the hard carbon film is further improved. In particular, regarding processing marks, in the intermediate layer formed at the processing mark location, a film stress such as elongation or compression is generated at that location, and due to this film stress,
It is considered that poor adhesion of the intermediate layer has occurred, and the phenomenon that the adhesion is deteriorated due to the film stress does not occur due to the disappearance of the processing mark. As a result,
In the guide bush of the present invention, the phenomenon that the intermediate layer peels does not occur, therefore, the adhesion of the hard carbon film formed on the upper surface of the intermediate layer is also improved, and the service life of the guide bush is greatly extended as compared with the conventional art. And reliability for long-term use is improved.

This hard carbon film is a black film and has properties very similar to diamond. That is, the hard carbon film has excellent characteristics such as high mechanical hardness, low coefficient of friction, good electrical insulation, high thermal conductivity, and high corrosion resistance. For this reason, the guide bush of the present invention can suppress the wear of the inner peripheral surface that comes into contact with the workpiece and suppress the occurrence of scratches on the workpiece in heavy cutting in which the cutting amount is large and the processing speed is large. And the occurrence of seizure between the guide bush and the workpiece can be suppressed.

Further, the guide bush of the present invention is provided with a hard carbon film under a middle layer on the inner peripheral surface thereof through a superhard member having high hardness. By providing a high-hardness super-hard member under the hard carbon film in this manner, local peeling and wear of the hard carbon film can be suppressed, and the reliability of the guide bush for long-term use can be further improved. Can be.

In the present invention, a structure in which an intermediate layer is provided between the super hard member and the hard carbon film is employed.
As the intermediate layer, in the guide bush of the present invention, a structure constituted by a single layer film or a structure constituted by a laminated film is adopted. When the intermediate layer is composed of a single layer film, a silicon carbide film (SiC) or a tungsten carbide film (WC)
When it is constituted by an alloy material film containing carbon, such as a titanium film (Ti) or chromium (Cr), and a silicon film (Si) or a germanium film (Ge). Constitute.

When the intermediate layer is interposed between the super-hard member and the hard carbon film, the adhesion of the hard carbon film increases. When the intermediate layer and the hard carbon film were peeled off in detail using a conventional guide bush, the intermediate layer and the hard carbon film could not obtain the adhesion with cobalt contained as a binder in the super hard member, It was peeled off from that location. The cause is not well understood, but one of the causes is thought to be that cobalt is oxidized, an oxide film with poor adhesion is formed, and the hard carbon film and the intermediate layer peel off from the inner peripheral surface of the guide bush. I guess.

Therefore, in the guide bush of the present invention, cobalt contained as a binder in the super hard member is removed from the surface of the super hard member on which the intermediate layer is formed.
In this way, cobalt that causes poor adhesion of the intermediate layer is removed from the inner peripheral surface of the guide bush. Therefore, the hard carbon film can be formed on the inner peripheral surface of the guide bush with good adhesion, and as a result, the peeling phenomenon of the hard carbon film on the inner peripheral surface of the guide bush does not occur.

In the method of forming a hard carbon film on a guide bush according to the present invention, an auxiliary electrode connected to a ground potential is disposed at the center of the opening on the inner surface of the guide bush to form a hard carbon film. Then, a negative DC voltage or a high-frequency voltage is applied to the guide bush.

As a result, an auxiliary electrode connected to the ground potential is provided on the inner surface of the guide bush opening where the electrodes of the same potential face each other, so that the same potential does not face each other. Such a potential state is the most desirable state for plasma enhanced chemical vapor deposition, and no hollow discharge occurs. Therefore, a hard carbon film having good adhesion can be formed on the guide bush.

In addition, in the method for forming a hard carbon film according to the present invention, the auxiliary electrode is arranged on the inner surface of the opening of the guide bush as described above, and the potential characteristics become uniform on the inner surface of the opening in the longitudinal direction of the guide bush. . As a result, there is no generation of a film thickness distribution of the hard carbon film formed on the inner surface of the opening of the guide bush, and an effect that a uniform film thickness can be formed between the opening end face and the inner side of the opening.

Further, in the method for forming a hard carbon film of the present invention, a hard DC film is formed by applying a DC positive voltage from an auxiliary electrode power source to an auxiliary electrode provided at the center of the inner surface of the sample opening. . For this reason, an effect of collecting electrons in a region around the auxiliary electrode to which a DC positive voltage is applied occurs,
The area around the auxiliary electrode has a high electron density.

When the electron density is increased as described above, the collision probability between the gas molecules containing carbon and the electrons is inevitably increased, ionization of the gas molecules is promoted, and the plasma density in the region around the auxiliary electrode is increased. . For this reason, in the film forming method of the present invention in which a DC positive voltage is applied to the auxiliary electrode to form a hard carbon film, the film formation speed of the hard carbon film is smaller than when no DC positive voltage is applied to the auxiliary electrode. It will be much higher.

Further, when the opening size of the sample becomes smaller and the gap between the inner surface of the opening and the auxiliary electrode becomes smaller, when a hard carbon film is formed without applying a DC positive voltage to the auxiliary electrode, plasma is generated on the inner surface of the opening. It does not occur and a film cannot be formed. On the other hand, in the method for forming a hard carbon film of the present invention, a DC positive voltage is applied from an auxiliary electrode power source to an auxiliary electrode disposed on the inner surface of the opening to forcibly collect electrons on the inner surface of the opening around the auxiliary electrode. Therefore, plasma can be generated around the auxiliary electrode.

Therefore, in the method of forming a hard carbon film using an auxiliary electrode to which a DC positive voltage is not applied, the present invention which uses an auxiliary electrode to which a DC positive voltage is applied even to a sample having a small opening size where a film cannot be formed. If a method for forming a hard carbon film is applied, a film can be formed.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view showing an inner peripheral surface of a guide bush according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing an inner peripheral surface of a guide bush in the embodiment of the present invention.

FIG. 3 is a sectional view showing a guide bush according to the embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating a method of forming a coating of an intermediate layer among the methods of forming a coating on a guide bush according to the embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a method of forming a hard carbon film among the methods of forming a film on a guide bush according to the embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating a method of forming a hard carbon film in the method of forming a film on the guide bush according to the embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating a method of forming a hard carbon film among the methods of forming a film on a guide bush according to an embodiment of the present invention.

FIG. 8 is a cross-sectional view showing the vicinity of a main axis of a lathe using a guide bush for forming a hard carbon film by a method for forming a hard carbon film on a guide bush according to an embodiment of the present invention.

FIG. 9 is a cross-sectional view showing the vicinity of a main shaft of a lathe using a guide bush for forming a hard carbon film on a guide bush according to an embodiment of the present invention.

FIG. 10 is a cross-sectional view illustrating a method of forming a hard carbon film in the method of forming a film on the guide bush according to the embodiment of the present invention.

FIG. 11 is a cross-sectional view illustrating a method of forming a hard carbon film among the methods of forming a film on a guide bush according to the embodiment of the present invention.

FIG. 12 is a cross-sectional view illustrating a method of forming a hard carbon film in the method of forming a film on the guide bush according to the embodiment of the present invention.

FIG. 13 is a graph showing a relationship between an auxiliary electrode voltage and a film thickness in a method for forming a hard carbon film on a guide bush according to an embodiment of the present invention.

FIG. 14 is a cross-sectional view showing a method of forming a hard carbon film on a guide bush according to a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Guide bush 12 Carbide member 14 Intermediate layer 15 Hard carbon film 61 Vacuum chamber 63 Gas inlet 71 Auxiliary electrode

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takashi Toida 840, Takeno, Shimotomi, Tokorozawa-shi, Saitama F-term in Citizen Watch Co., Ltd. Tokorozawa Office (reference) CA13

Claims (51)

[Claims] 1. A substantially cylindrical shape having a central opening penetrating in the axial direction, an outer peripheral tapered surface formed at one end in a longitudinal direction and a slit for providing elasticity thereto, and a slit at the other end. It has a screw part for attaching to the column of the automatic lathe, and has an inner peripheral surface for holding the workpiece on the inner periphery of the part where the outer peripheral taper surface is formed. Workpiece inserted into the opening,
A guide that holds the workpiece in such a manner that it can be rotated and slid in the axial direction near the cutting tool by an inner peripheral surface that holds the workpiece, an intermediate layer is provided on the inner peripheral surface, and a hard carbon film is formed on the intermediate layer. A guide bush, wherein the surface of the hard carbon film is uneven. 2. A substantially cylindrical shape having a central opening penetrating in the axial direction. An outer peripheral tapered surface and a slit for giving elasticity thereto are formed at one end in the longitudinal direction, and at the other end. It has a screw part for attaching to the column of the automatic lathe, and has an inner peripheral surface for holding the workpiece on the inner periphery of the part where the outer peripheral taper surface is formed. Workpiece inserted into the opening,
An inner peripheral surface that holds the workpiece slidably and slidably in the axial direction near the cutting tool, a superhard member is provided on the inner peripheral surface, and an intermediate layer is provided on the superhard member. A guide bush having a hard carbon film formed on an intermediate layer thereof, wherein the surface of the hard carbon film is uneven. 3. It has a substantially cylindrical shape having a central opening penetrating in the axial direction. An outer peripheral tapered surface and a slit for giving elasticity thereto are formed at one end in the longitudinal direction and at the other end. It has a screw part for attaching to the column of the automatic lathe, and has an inner peripheral surface for holding the workpiece on the inner periphery of the part where the outer peripheral taper surface is formed. Workpiece inserted into the opening,
An inner peripheral surface that holds the workpiece slidably and slidably in the axial direction near the cutting tool, a superhard member is provided on the inner peripheral surface, and an intermediate layer is provided on the superhard member. A guide bush in which a hard carbon film is formed on the intermediate layer, wherein the surface of the super hard member is uneven, and the surface of the hard carbon film is uneven so as to follow the uneven surface of the super hard member. Guide bush characterized by the above-mentioned. 4. A substantially cylindrical shape having a central opening penetrating in the axial direction, an outer peripheral tapered surface and a slit for providing elasticity are formed at one end in the longitudinal direction, and at the other end. It has a screw part for attaching to the column of the automatic lathe, and has an inner peripheral surface for holding the workpiece on the inner periphery of the part where the outer peripheral taper surface is formed. Workpiece inserted into the opening,
An inner peripheral surface that holds the workpiece holds the workpiece in a rotatable and axially slidable manner near the cutting tool, and a carbide member containing at least cobalt is provided on the inner peripheral surface. A guide bush in which an intermediate layer is provided, and a hard carbon film is formed on the intermediate layer. The surface of the super hard member is uneven due to the removal of cobalt, so as to follow the uneven surface of the super hard member. A guide bush wherein the surface of the hard carbon film is uneven. 5. The guide bush according to claim 1, wherein the intermediate layer is formed as a single layer. 6. The guide bush according to claim 5, wherein the intermediate layer is made of an alloy material containing carbon. 7. A guide bush, wherein the intermediate layer is made of silicon carbide or tungsten carbide from the carbon-containing alloy material according to claim 6. 8. The guide bush according to claim 1, wherein the intermediate layer comprises a plurality of layers. 9. The intermediate layer according to claim 8, comprising a lower first intermediate layer made of titanium or chromium and an upper second intermediate layer made of silicon or germanium. guide bush. 10. A substantially cylindrical shape having a central opening penetrating in an axial direction, an outer peripheral tapered surface formed at one end in a longitudinal direction and a slit for giving elasticity thereto, and an automatic taper at the other end. It has a screw part for attaching to the lathe column, and has an inner peripheral surface for holding the workpiece on the inner periphery of the part where the outer peripheral taper surface is formed, and the central opening by being attached to the automatic lathe Workpiece inserted in
An inner peripheral surface that holds the workpiece slidably and slidably in the axial direction near the cutting tool, a superhard member is provided on the inner peripheral surface, and an intermediate layer is provided on the superhard member. A method of forming a coating on a guide bush in which a hard carbon film is formed on an intermediate layer, the step of forming irregularities by etching the surface of the super-hard material; After evacuating the vacuum chamber, introducing an argon gas into the vacuum chamber from a gas inlet and forming an intermediate layer by sputtering, and forming the intermediate layer. The guide bush is arranged in the vacuum chamber so that the auxiliary electrode connected to the ground potential is inserted into the inner surface of the guide bush, and after exhausting the vacuum chamber, a gas containing carbon is introduced into the vacuum chamber from the gas inlet. And Applying a DC voltage to the guide bush, applying a DC voltage to the anode, applying an AC voltage to the filament to generate plasma, and forming a hard carbon film on the guide bush. The method of forming the coating. 11. A substantially cylindrical shape having a central opening penetrating in the axial direction, an outer peripheral tapered surface formed at one end in the longitudinal direction, and a slit for providing elasticity thereto, and an automatic taper at the other end. It has a screw part for attaching to the lathe column, and has an inner peripheral surface for holding the workpiece on the inner periphery of the part where the outer peripheral taper surface is formed, and the central opening by being attached to the automatic lathe Workpiece inserted in
An inner peripheral surface that holds the workpiece holds the workpiece in a rotatable and axially slidable manner near the cutting tool, and a carbide member containing at least cobalt is provided on the inner peripheral surface. A method of forming a coating on a guide bush in which an intermediate layer is provided and a hard carbon film is formed on the intermediate layer, wherein a step of forming irregularities by etching cobalt on the surface of the super hard material; A step of arranging the inner peripheral surface of the vacuum chamber so as to face the target, evacuating the vacuum chamber, introducing an argon gas into the vacuum chamber from a gas inlet, and forming an intermediate layer by sputtering. The guide bush is arranged in the vacuum chamber so that the auxiliary electrode connected to the ground potential is inserted into the inner surface of the guide bush having the intermediate layer formed therein. Step of introducing a gas containing carbon into a vacuum chamber, applying a DC voltage to the guide bush, applying a DC voltage to the anode, applying an AC voltage to the filament, and generating plasma to form a hard carbon film on the guide bush. A method for forming a coating on a guide bush, comprising: 12. The method for forming a coating on a guide bush according to claim 11, wherein the step of removing cobalt by etching is performed by wet etching. 13. A method for forming a coating on a guide bush, wherein the wet etching according to claim 12 is performed using a mixed solution of sodium hydroxide and hydrogen peroxide solution. 14. A method for forming a film on a guide bush, wherein the wet etching according to claim 12 is performed using a hydrogen peroxide solution. 15. The method for forming a coating on a guide bush, wherein the intermediate layer according to claim 10 or 11 is composed of one or more layers. 16. A method for forming a coating on a guide bush, wherein the gas containing carbon according to claim 10 or 11 uses benzene. 17. A substantially cylindrical shape having a central opening penetrating in the axial direction, an outer peripheral tapered surface formed at one end in the longitudinal direction, and a slit for giving elasticity thereto, and an automatic taper at the other end. It has a screw part for attaching to the lathe column, and has an inner peripheral surface for holding the workpiece on the inner periphery of the part where the outer peripheral taper surface is formed, and the central opening by being attached to the automatic lathe Workpiece inserted in
An inner peripheral surface that holds the workpiece slidably and slidably in the axial direction near the cutting tool, a superhard member is provided on the inner peripheral surface, and an intermediate layer is provided on the superhard member. A method of forming a coating on a guide bush in which a hard carbon film is formed on an intermediate layer, the step of forming irregularities by etching the surface of the super-hard material; After evacuating the vacuum chamber, introducing an argon gas into the vacuum chamber from a gas inlet and forming an intermediate layer by sputtering, and forming the intermediate layer. The guide bush is arranged in the vacuum chamber so that the auxiliary electrode connected to the ground potential is inserted into the inner surface of the guide bush, and after exhausting the vacuum chamber, a gas containing carbon is introduced into the vacuum chamber from the gas inlet. And The high frequency voltage is applied to the id bush, the method of forming the film into the guide bush, characterized in that a step of forming a hard carbon film on the guide bush by generating plasma. 18. A substantially cylindrical shape having a central opening penetrating in the axial direction, an outer tapered surface formed at one end in the longitudinal direction, and a slit for providing elasticity thereto, and an automatic taper formed at the other end. It has a screw part for attaching to the lathe column, and has an inner peripheral surface for holding the workpiece on the inner periphery of the part where the outer peripheral taper surface is formed, and the central opening by being attached to the automatic lathe Workpiece inserted in
An inner peripheral surface that holds the workpiece holds the workpiece in a rotatable and axially slidable manner near the cutting tool, and a carbide member containing at least cobalt is provided on the inner peripheral surface. A method of forming a coating on a guide bush in which an intermediate layer is provided and a hard carbon film is formed on the intermediate layer, wherein a step of forming irregularities by etching cobalt on the surface of the super hard material; A step of arranging the inner peripheral surface of the vacuum chamber so as to face the target, evacuating the vacuum chamber, introducing an argon gas into the vacuum chamber from a gas inlet, and forming an intermediate layer by sputtering. The guide bush is arranged in the vacuum chamber so that the auxiliary electrode connected to the ground potential is inserted into the inner surface of the guide bush having the intermediate layer formed therein. Introducing a gas containing carbon into the vacuum chamber, applying a high-frequency voltage to the guide bush, generating plasma, and forming a hard carbon film on the guide bush. Forming method. 19. The method of forming a coating on a guide bush according to claim 18, wherein the step of removing cobalt by etching is performed by wet etching. 20. A method for forming a film on a guide bush, wherein the wet etching according to claim 19 is performed by a mixed solution of sodium hydroxide and hydrogen peroxide solution. 21. A method for forming a film on a guide bush, wherein the wet etching according to claim 19 is performed with a hydrogen peroxide solution. 22. A method for forming a coating on a guide bush, wherein the intermediate layer according to claim 17 or 18 comprises one or more layers. 23. A method for forming a coating on a guide bush, wherein the gas containing carbon according to claim 17 or 18 is methane. 24. A substantially cylindrical shape having a central opening penetrating in the axial direction, an outer peripheral tapered surface formed at one end in the longitudinal direction and a slit for giving elasticity thereto, and an automatic taper at the other end. It has a screw part for attaching to the lathe column, and has an inner peripheral surface for holding the workpiece on the inner periphery of the part where the outer peripheral taper surface is formed, and the central opening by being attached to the automatic lathe Workpiece inserted in
An inner peripheral surface that holds the workpiece slidably and slidably in the axial direction near the cutting tool, a superhard member is provided on the inner peripheral surface, and an intermediate layer is provided on the superhard member. A method of forming a coating on a guide bush in which a hard carbon film is formed on an intermediate layer, the step of forming irregularities by etching the surface of the super-hard material; After evacuating the vacuum chamber, introducing an argon gas into the vacuum chamber from a gas inlet and forming an intermediate layer by sputtering, and forming the intermediate layer. The guide bush is arranged in the vacuum chamber so that the auxiliary electrode connected to the ground potential is inserted into the inner surface of the guide bush, and after exhausting the vacuum chamber, a gas containing carbon is introduced into the vacuum chamber from the gas inlet. And Applying a DC voltage to the id bush, the method of forming the film into the guide bush, characterized in that a step of forming a hard carbon film on the guide bush by generating plasma. 25. It has a substantially cylindrical shape with a central opening penetrating in the axial direction. An outer peripheral tapered surface is formed at one end in the longitudinal direction and a slit is formed at the other end to make it elastic. It has a screw part for attaching to the lathe column, and has an inner peripheral surface for holding the workpiece on the inner periphery of the part where the outer peripheral taper surface is formed, and the central opening by being attached to the automatic lathe Workpiece inserted in
An inner peripheral surface that holds the workpiece holds the workpiece in a rotatable and axially slidable manner near the cutting tool, and a carbide member containing at least cobalt is provided on the inner peripheral surface. A method of forming a coating on a guide bush in which an intermediate layer is provided and a hard carbon film is formed on the intermediate layer, wherein a step of forming irregularities by etching cobalt on the surface of the super hard material; A step of arranging the inner peripheral surface of the vacuum chamber so as to face the target, evacuating the vacuum chamber, introducing an argon gas into the vacuum chamber from a gas inlet, and forming an intermediate layer by sputtering. The guide bush is arranged in the vacuum chamber so that the auxiliary electrode connected to the ground potential is inserted into the inner surface of the guide bush having the intermediate layer formed therein. Introducing a gas containing carbon into the vacuum chamber, applying a DC voltage to the guide bush, and generating a plasma to form a hard carbon film on the guide bush. Forming method. 26. A method according to claim 25, wherein the step of removing cobalt by etching is performed by wet etching. 27. A method for forming a coating on a guide bush, wherein the wet etching according to claim 26 is performed using a mixed solution of sodium hydroxide and hydrogen peroxide solution. 28. A method according to claim 26, wherein the wet etching is performed using a hydrogen peroxide solution. 29. A method for forming a coating on a guide bush, wherein the intermediate layer according to claim 24 or 25 comprises one or more layers. 30. A method for forming a coating on a guide bush, wherein methane is used as the gas containing carbon according to claim 24 or 25. 31. A substantially cylindrical shape having a central opening penetrating in the axial direction, an outer peripheral tapered surface and a slit for giving elasticity thereto are formed at one end in the longitudinal direction, and the other end is automatically formed. It has a screw part for attaching to the lathe column, and has an inner peripheral surface for holding the workpiece on the inner periphery of the part where the outer peripheral taper surface is formed, and the central opening by being attached to the automatic lathe Workpiece inserted in
An inner peripheral surface that holds the workpiece slidably and slidably in the axial direction near the cutting tool, a superhard member is provided on the inner peripheral surface, and an intermediate layer is provided on the superhard member. A method of forming a coating on a guide bush in which a hard carbon film is formed on an intermediate layer, the step of forming irregularities by etching the surface of the super-hard material; After evacuating the vacuum chamber, introducing an argon gas into the vacuum chamber from a gas inlet and forming an intermediate layer by sputtering, and forming the intermediate layer. The guide bush is arranged in the vacuum chamber so that the auxiliary electrode connected to the DC positive voltage is inserted into the inner surface of the guide bush, and after exhausting the vacuum chamber, the gas containing carbon is introduced into the vacuum chamber from the gas inlet. Introduce Applying a DC voltage to the guide bush, applying a DC voltage to the anode, applying an AC voltage to the filament to generate plasma, and forming a hard carbon film on the guide bush. The method of forming the coating. 32. A substantially cylindrical shape having a central opening penetrating in the axial direction, an outer peripheral tapered surface formed at one end in a longitudinal direction and a slit for giving elasticity thereto, and an automatic taper at the other end. It has a screw part for attaching to the lathe column, and has an inner peripheral surface for holding the workpiece on the inner periphery of the part where the outer peripheral taper surface is formed, and the central opening by being attached to the automatic lathe Workpiece inserted in
An inner peripheral surface that holds the workpiece holds the workpiece in a rotatable and axially slidable manner near the cutting tool, and a carbide member containing at least cobalt is provided on the inner peripheral surface. A method of forming a coating on a guide bush in which an intermediate layer is provided and a hard carbon film is formed on the intermediate layer, wherein a step of forming irregularities by etching cobalt on the surface of the super hard material; A step of arranging the inner peripheral surface of the vacuum chamber so as to face the target, evacuating the vacuum chamber, introducing an argon gas into the vacuum chamber from a gas inlet, and forming an intermediate layer by sputtering. The guide bush is arranged in a vacuum chamber so that an auxiliary electrode connected to a DC positive voltage is inserted into the inner surface of the guide bush having the intermediate layer formed therein, and after evacuating the vacuum chamber, a gas inlet is provided. A gas containing carbon is introduced into the vacuum chamber, a DC voltage is applied to the guide bush, a DC voltage is applied to the anode, an AC voltage is applied to the filament to generate plasma, and a hard carbon film is formed on the guide bush. And forming a film on the guide bush. 33. The method of forming a coating on a guide bush according to claim 32, wherein the step of removing cobalt by etching according to claim 32 is performed by wet etching. 34. A method for forming a coating on a guide bush, wherein the wet etching according to claim 33 is performed by a mixed solution of sodium hydroxide and hydrogen peroxide solution. 35. A method according to claim 33, wherein the wet etching is performed using a hydrogen peroxide solution. 36. A method for forming a coating on a guide bush, wherein the intermediate layer according to claim 31 or 32 comprises one or more layers. 37. A method for forming a film on a guide bush, wherein the gas containing carbon according to claim 31 or 32 is benzene. 38. It has a substantially cylindrical shape with a central opening penetrating in the axial direction. An outer peripheral tapered surface is formed at one end in the longitudinal direction and a slit is formed at the other end to make it elastic. It has a screw part for attaching to the lathe column, and has an inner peripheral surface for holding the workpiece on the inner periphery of the part where the outer peripheral taper surface is formed, and the central opening by being attached to the automatic lathe Workpiece inserted in
An inner peripheral surface that holds the workpiece slidably and slidably in the axial direction near the cutting tool, a superhard member is provided on the inner peripheral surface, and an intermediate layer is provided on the superhard member. A method of forming a coating on a guide bush in which a hard carbon film is formed on an intermediate layer, the step of forming irregularities by etching the surface of the super-hard material; After evacuating the vacuum chamber, introducing an argon gas into the vacuum chamber from a gas inlet and forming an intermediate layer by sputtering, and forming the intermediate layer. The guide bush is arranged in the vacuum chamber so that the auxiliary electrode connected to the DC positive voltage is inserted into the inner surface of the guide bush, and after exhausting the vacuum chamber, the gas containing carbon is introduced into the vacuum chamber from the gas inlet. Introduce The high frequency voltage is applied to the guide bush, the method of forming the film into the guide bush, characterized in that it comprises a step of generating plasma to form a hard carbon film on the guide bush. 39. It has a substantially cylindrical shape with a central opening penetrating in the axial direction. An outer peripheral tapered surface and a slit for giving elasticity thereto are formed at one end in the longitudinal direction, and an automatic slit is formed at the other end. It has a screw part for attaching to the lathe column, and has an inner peripheral surface for holding the workpiece on the inner periphery of the part where the outer peripheral taper surface is formed, and the central opening by being attached to the automatic lathe Workpiece inserted in
An inner peripheral surface that holds the workpiece holds the workpiece in a rotatable and axially slidable manner near the cutting tool, and a carbide member containing at least cobalt is provided on the inner peripheral surface. A method of forming a coating on a guide bush in which an intermediate layer is provided and a hard carbon film is formed on the intermediate layer, wherein a step of forming irregularities by etching cobalt on the surface of the super hard material; A step of arranging the inner peripheral surface of the vacuum chamber so as to face the target, evacuating the vacuum chamber, introducing an argon gas into the vacuum chamber from a gas inlet, and forming an intermediate layer by sputtering. The guide bush is arranged in a vacuum chamber so that an auxiliary electrode connected to a DC positive voltage is inserted into the inner surface of the guide bush having the intermediate layer formed therein, and after evacuating the vacuum chamber, a gas inlet is provided. Introducing a gas containing carbon into the vacuum chamber, applying a high-frequency voltage to the guide bush, generating plasma, and forming a hard carbon film on the guide bush. Formation method. 40. A method for forming a film on a guide bush according to claim 39, wherein the step of removing cobalt by etching is performed by wet etching. 41. A method for forming a film on a guide bush, wherein the wet etching according to claim 40 is performed using a mixed solution of sodium hydroxide and hydrogen peroxide solution. 42. A method according to claim 40, wherein the wet etching is performed using a hydrogen peroxide solution. 43. A method of forming a coating on a guide bush, wherein the intermediate layer according to claim 38 or 39 is formed of one or more layers. 44. A method for forming a film on a guide bush, wherein the gas containing carbon according to claim 38 or 39 is methane. 45. A substantially cylindrical shape having a central opening penetrating in the axial direction. An outer peripheral tapered surface and a slit for giving elasticity thereto are formed at one end in the longitudinal direction, and an automatic slit is formed at the other end. It has a screw part for attaching to the lathe column, and has an inner peripheral surface for holding the workpiece on the inner periphery of the part where the outer peripheral taper surface is formed, and the central opening by being attached to the automatic lathe Workpiece inserted in
An inner peripheral surface that holds the workpiece slidably and slidably in the axial direction near the cutting tool, a superhard member is provided on the inner peripheral surface, and an intermediate layer is provided on the superhard member. A method of forming a coating on a guide bush in which a hard carbon film is formed on an intermediate layer, the step of forming irregularities by etching the surface of the super-hard material; After evacuating the vacuum chamber, introducing an argon gas into the vacuum chamber from a gas inlet and forming an intermediate layer by sputtering, and forming the intermediate layer. The guide bush is arranged in the vacuum chamber so that the auxiliary electrode connected to the DC positive voltage is inserted into the inner surface of the guide bush, and after exhausting the vacuum chamber, the gas containing carbon is introduced into the vacuum chamber from the gas inlet. Introduce Applying a DC voltage to the guide bush, the method of forming the film into the guide bush, characterized in that it comprises a step of generating plasma to form a hard carbon film on the guide bush. 46. A substantially cylindrical shape having a central opening penetrating in the axial direction. An outer peripheral tapered surface is formed at one end in the longitudinal direction and a slit is formed at the other end to make it elastic. It has a screw part for attaching to the lathe column, and has an inner peripheral surface for holding the workpiece on the inner periphery of the part where the outer peripheral taper surface is formed, and the central opening by being attached to the automatic lathe Workpiece inserted in
An inner peripheral surface that holds the workpiece holds the workpiece in a rotatable and axially slidable manner near the cutting tool, and a carbide member containing at least cobalt is provided on the inner peripheral surface. A method of forming a coating on a guide bush in which an intermediate layer is provided and a hard carbon film is formed on the intermediate layer, wherein a step of forming irregularities by etching cobalt on the surface of the super hard material; A step of arranging the inner peripheral surface of the vacuum chamber so as to face the target, evacuating the vacuum chamber, introducing an argon gas into the vacuum chamber from a gas inlet, and forming an intermediate layer by sputtering. The guide bush is arranged in a vacuum chamber so that an auxiliary electrode connected to a DC positive voltage is inserted into the inner surface of the guide bush having the intermediate layer formed therein, and after evacuating the vacuum chamber, a gas inlet is provided. Introducing a gas containing carbon into the vacuum chamber, applying a DC voltage to the guide bush, generating plasma, and forming a hard carbon film on the guide bush. Formation method. 47. A method according to claim 46, wherein the step of removing cobalt by etching is performed by wet etching. 48. A method for forming a film on a guide bush, wherein the wet etching according to claim 47 is performed using a mixed solution of sodium hydroxide and hydrogen peroxide solution. 49. A method according to claim 47, wherein the wet etching is performed using a hydrogen peroxide solution. 50. The method for forming a coating on a guide bush according to claim 45, wherein the intermediate layer comprises one or more layers. 51. A method for forming a film on a guide bush, wherein the gas containing carbon according to claim 45 or 46 is methane.