JP3665247B2 - guide bush - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a guide bush which is mounted on an automatic lathe and holds a round bar-like workpiece so as to be rotatable and slidable in the axial direction near a cutting tool (blade).
[0002]
[Prior art]
Guide bushes provided on an automatic lathe column of an automatic lathe and holding a round bar-like workpiece so as to be rotatable near a cutting tool include a rotary type and a fixed type. The rotary type always holds the work piece so that it can slide in the axial direction while rotating together with the work piece, and the fixed type allows the work piece to rotate and slide in the axial direction without rotating. Hold.
[0003]
Each type of guide bushing has an outer peripheral tapered surface, a slit for imparting elasticity to the guide bush, a screw portion for attaching to the column, and an inner peripheral surface for holding the workpiece. Since the surface is always in sliding contact with the work piece, it is easy to wear, especially in the case of a fixed type.
[0004]
For this reason, a cemented carbide or ceramic is fixedly provided by brazing or the like on the inner peripheral surface of the guide bush that comes into sliding contact with the workpiece by the rotation or sliding of the workpiece, for example, Japanese Patent Laid-Open No. 4-141303. It has been proposed as seen in the publication. Thus, the provision of cemented carbide or ceramics excellent in wear resistance and heat resistance on the inner peripheral surface of the guide bush has an effect of suppressing the wear to some extent.
[0005]
However, even if cemented carbide or ceramics is provided on the inner peripheral surface in this way, for heavy cutting where the cutting amount is large and the machining speed is large with an automatic lathe, cemented carbide and ceramics also have a large friction coefficient and thermal conductivity. Since there is a problem that the workpiece is scratched or the gap between the guide bush and the workpiece is reduced in the diametrical direction, seizure occurs, increasing the cutting amount and the processing speed. I could not.
[0006]
The fixed guide bush can hold the work piece without blurring of its axis, so it can be machined with high roundness and high accuracy, it has less noise, and the structure of the automatic lathe is not complicated. There are advantages such as compactness.
[0007]
[Problems to be solved by the invention]
However, since the wear on the inner peripheral surface of the guide bush is much larger than in the case of the rotary type, there is a problem that it is difficult to further increase the cutting amount and the processing speed.
[0008]
Further, in an automatic lathe, a once machined region of a workpiece is often drawn into the guide bush again to be gripped and cut again. In such a case, a small protrusion called a burr is often generated at the edge of the machined part of the workpiece, and the burr is used as a guide when pulled into the guide bush. There is a problem that scratches occur in the vicinity of the inner peripheral surface of the opening end surface of the bush and in the inner peripheral surface. The occurrence of this burr is remarkable when the work piece is made of a difficult-to-cut material with high toughness, and in that case, the above-mentioned problem is also increased.
[0009]
This invention solves such a problem, dramatically improves the wear resistance of the inner peripheral surface of the guide bush that contacts the workpiece, without causing scratches or seizure on the workpiece, It is possible to increase the cutting amount and processing speed applied to the automatic lathe, and even when the cut portion of the workpiece is pulled back into the guide bush and cut again, the workpiece burr It is an object of the present invention to make it possible to use the same guide bush for a long period of time so as not to cause scratches on the inner peripheral surface of the guide bush and the inner peripheral surface portion of the opening end surface thereof.
[0010]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention forms a hard carbon film on the inner peripheral surface in sliding contact with the workpiece of the guide bush as described above and on the inner peripheral surface vicinity portion of the end surface where the inner peripheral surface opens. Provide a guide bush.
[0011]
This hard carbon film is a hydrogenated amorphous carbon film and has a property very similar to diamond, and is also called diamond-like carbon (DLC).
This hard carbon (DLC) film has high hardness (3000 Vv or more in Vickers hardness), excellent wear resistance, a small friction coefficient (1/8 of cemented carbide), and excellent corrosion resistance.
[0012]
For this reason, the guide bush according to the present invention in which the hard carbon film is provided on the inner peripheral surface in sliding contact with the workpiece and the inner peripheral surface portion of the end surface where the inner peripheral surface opens is provided with a conventional cemented carbide or ceramic. Abrasion resistance is drastically improved compared to those provided on the peripheral surface.
Therefore, if this is used as a fixed guide bush for an automatic lathe, the workpiece will not be scratched or seized even when heavy cutting is performed with a large cutting amount and a large machining speed. It becomes possible to perform highly accurate processing over a long period of time.
[0013]
When a hard carbon film is formed on the inner peripheral surface of the guide bush and in the vicinity of the opening end thereof through an intermediate layer that enhances adhesion to the hard carbon film, the hard carbon film can be formed more firmly and hardly peeled off. it can.
For example, when the intermediate layer is formed of a two-layer film of a lower layer made of titanium or chromium and an upper layer made of silicon carbide, the lower layer adheres to the inner peripheral surface of the guide bush (base material alloy tool steel). And the upper layer is strongly bonded to the hard carbon film, so that a hard carbon film with good adhesion can be provided.
[0014]
Thereby, even if heavy cutting with a large cutting amount and a large machining speed is performed with an automatic lathe equipped with this guide bush, there is no possibility that the hard carbon film is peeled off. Alternatively, a cemented carbide member containing at least tungsten, carbon and cobalt is provided on the base material in the vicinity of the inner circumferential surface of the guide bush, or a carburized layer is formed, and the inner circumferential surface of the cemented carbide member or the carburized layer and the inside thereof are formed. A hard carbon film may be provided in the vicinity of the inner peripheral surface of the end surface where the peripheral surface is open. In this case, the adhesion can be further improved by providing the hard carbon film via an intermediate layer similar to the above.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[Description of Automatic Lathe Using Guide Bush of this Invention]
First, the structure of an automatic lathe using a guide bush according to the present invention will be briefly described.
[0016]
FIG. 29 is a cross-sectional view showing only the vicinity of the spindle of a numerically controlled automatic lathe. This automatic lathe is provided with a fixed guide bush device 37 that is used in a state in which the guide bush 11 is fixed and a work piece 51 (shown in phantom line) is rotatably held on its inner peripheral surface 11b. It is.
[0017]
The headstock 17 is slidable in the horizontal direction in the figure on a bed (not shown) of the numerically controlled automatic lathe.
The spindle stock 17 is provided with a spindle 19 that is supported by a bearing 21 so as to be rotatable. A collet chuck 13 is attached to the tip of the main shaft 19.
[0018]
The collet chuck 13 is disposed in the center hole of the chuck sleeve 41. The outer peripheral tapered surface 13a at the tip of the collet chuck 13 and the inner peripheral tapered surface 41a of the chuck sleeve 41 are in surface contact with each other.
Further, a spring 25 in which a strip-shaped spring material is coiled is provided at the rear end portion of the collet chuck 13 in the intermediate sleeve 29. The collet chuck 13 can be pushed out of the intermediate sleeve 29 by the action of the spring 25.
[0019]
The tip position of the collet chuck 13 is in contact with a cap nut 27 that is screwed to the tip of the main shaft 19 to regulate the position. For this reason, the collet chuck 13 is prevented from jumping out of the intermediate sleeve 29 by the spring force of the spring 25.
A chuck opening / closing mechanism 31 is provided at the rear end portion of the intermediate sleeve 29 via the intermediate sleeve 29. By opening and closing the chuck opening / closing claw 33, the collet chuck 13 is opened and closed, and the workpiece 51 is gripped and released.
[0020]
That is, when the chuck opening / closing claw 33 of the chuck opening / closing mechanism 31 moves so that the tip ends thereof open to each other, the portion of the chuck opening / closing claw 33 that is in contact with the intermediate sleeve 29 moves to the left in FIG. Press 29 to the left. By the movement of the intermediate sleeve 29 in the left direction, the chuck sleeve 41 that is in contact with the left end of the intermediate sleeve 29 moves in the left direction.
[0021]
The collet chuck 13 is prevented from jumping out of the main shaft 19 by a cap nut 27 screwed to the tip of the main shaft 19.
For this reason, the leftward movement of the chuck sleeve 41 strongly presses the outer peripheral tapered surface 13a of the portion where the slit of the collet chuck 13 is formed and the inner peripheral tapered surface 41a of the chuck sleeve 41, They move along the tapered surfaces.
[0022]
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 releasing the workpiece 51 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 tip ends of the chuck opening / closing claws 33 so as to close each other. except for.
Then, the intermediate sleeve 29 and the chuck sleeve 41 are moved rightward in the drawing by the restoring force of the spring 25.
[0023]
For this reason, 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 removed. As a result, the collet chuck 13 can increase the diameter of the inner peripheral surface by its own elastic force and can release the workpiece 51.
Further, a column 35 is provided in front of the headstock 17, and a guide bush device 37 is arranged there such that its central axis coincides with the main axis.
[0024]
The guide bush device 37 is a fixed guide bush device 37 that fixes the guide bush 11 and holds the workpiece 51 in a rotatable state on the inner peripheral surface 11 b of the guide bush 11.
The bush sleeve 23 is fitted into the center hole of the holder 39 fixed to the column 35, and an inner peripheral tapered surface 23 a is provided at the tip of the bush sleeve 23.
[0025]
And the guide bush 11 which formed the outer peripheral taper surface 11a and the slit 11c in the front-end | tip part is inserted in the center hole of this bush sleeve 23, and is arrange | positioned. By adjusting an adjustment nut 43 that is screwed to the threaded portion of the guide bush 11 at the rear end portion of the guide bush device 37, the clearance between the inner diameter of the guide bush 11 and the outer shape of the workpiece 51 is adjusted. can do.
[0026]
That is, when the adjustment nut 43 is rotated to the right, the guide bush 11 moves to the right in the drawing with respect to the bush sleeve 23, and the inner peripheral tapered surface 23 a of the bush sleeve 23 and the guide bush are the same as in the case of the collet chuck 13. This is because the outer peripheral tapered surface 11a of the guide bush 11 is pressed against each other, and the inner diameter of the distal end portion of the guide bush 11 becomes smaller.
[0027]
A cutting tool (blade) 45 is provided in front of the guide bush device 37.
The workpiece 51 is gripped by the collet chuck 13 of the main shaft 19 and supported by the guide bush device 37, and the workpiece 51 that penetrates the guide bush device 37 and protrudes into the machining area is cut by the cutting tool 45. A predetermined cutting process is performed by a combined motion of the forward and backward movement of the main shaft 17 and the movement of the headstock 17.
[0028]
Next, a rotary type guide bush device used in a state where the guide bush for gripping the workpiece is rotated will be described with reference to FIG. In FIG. 30, portions corresponding to those in FIG. 29 are denoted with the same reference numerals.
[0029]
As this rotary type guide bush device, there are a guide bush device in which the collet chuck 13 and the guide bush 11 rotate synchronously, and a guide bush device that rotates without synchronizing. In the guide bush device 37 shown in this figure, the collet chuck 13 and the guide bush 11 rotate in synchronization.
[0030]
The rotary type guide bush device 37 drives the guide bush device 37 by a rotation drive rod 47 protruding from the cap nut 27 of the main shaft 19. In place of the rotary drive rod 47, there is also a type in which the guide bush device 37 is driven by a gear or a belt pulley.
[0031]
The rotary type guide bush device 37 is arranged by fitting a bush sleeve 23 into a center hole of a holder 39 fixed to a column 35 so as to be rotatable via a bearing 21. Further, the guide bush 11 is fitted in the central hole of the bush sleeve 23.
[0032]
The bush sleeve 23 and the guide bush 11 have the same configuration as that described with reference to FIG. Then, by rotating an adjustment nut 43 that is screwed to the threaded portion of the guide bush 11 at the rear end portion of the guide bush device 37, the inner diameter of the guide bush 11 is reduced, and the inner diameter of the guide bush 11 is reduced. The gap dimension with the outer shape of the workpiece 51 can be adjusted.
Since the configuration other than the rotation of the guide bush device 37 is the same as the configuration of the automatic lathe described with reference to FIG. 29, the description thereof is omitted.
[0033]
[Description of the guide bush according to the present invention]
Next, the configuration of the guide bush according to the present invention will be described in various embodiments. FIG. 1 is a longitudinal sectional view showing an example of a guide bush according to the present invention, and FIG. 2 is a perspective view showing an appearance thereof.
[0034]
As shown in these drawings, the guide bush 11 shows a free state in which the tip portion is opened. The guide bush 11 is formed in a substantially cylindrical shape having a central opening 11j in the axial direction, has an outer peripheral tapered surface 11a at one end portion in the longitudinal direction, and has a screw portion 11f at the other end portion.
[0035]
Further, a through opening having a different opening diameter is provided at the center of the guide bush 11. And the inner peripheral surface 11b which hold | maintains the to-be-processed object 51 is formed in the inner periphery of the side in which the outer peripheral taper surface 11a was provided. A step portion 11g having an inner diameter larger than the inner diameter of the inner peripheral surface 11b is formed in a region other than the inner peripheral surface 11b.
[0036]
And the central opening 11j of this guide bush 11 forms the inner peripheral surface 11b which hold | maintains a to-be-processed object inside the one end part which provided the outer peripheral taper surface 11a, In area | regions other than this 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 three slits 11c at 120 ° intervals so as to divide the outer peripheral tapered surface 11a into three equal parts in the circumferential direction from the outer peripheral tapered surface 11a to the spring portion 11d.
[0037]
Then, when the outer peripheral tapered surface 11a of the guide bush 11 is pressed against the inner peripheral tapered surface of the bush sleeve described above, the spring portion 11d is bent, and the inner peripheral surface 11b and the workpiece 51 indicated by a virtual line in FIG. Can be adjusted.
Further, the guide bush 11 is provided with a fitting portion 11e between the spring portion 11d and the screw portion 11f. Then, by fitting the fitting portion 11e into the center hole of the bush sleeve 23 shown in FIGS. 29 and 30, the guide bush 11 can be disposed on the center line of the main shaft and in parallel to the main shaft center line. it can.
[0038]
As the material of the guide bush 11, alloy tool steel (SKS) is used, and after forming an outer shape and an inner shape, a quenching process and a tempering process are performed.
The guide bush 11 is provided with a gap of 5 μm to 10 μm in the radial direction between the inner peripheral surface 11 b and the workpiece 51 in a state where the outer peripheral tapered surface 11 a is closed. As a result, the workpiece 51 enters and exits and comes into sliding contact with the inner peripheral surface 11b, so that wear becomes a problem.
[0039]
Furthermore, when used in a fixed guide bushing device as shown in FIG. 29, the workpiece 51 held by the fixed guide bushing 11 is processed by rotating at a high speed. There is a problem in that seizure occurs due to an excessive pressing force of the workpiece 51 on the inner peripheral surface 11b due to a cutting load.
[0040]
In addition, as described above, when the machined region of the workpiece is drawn into the guide bush and cut again, the burrs remaining on the workpiece cause scratches on the inner peripheral surface or the opening edge of the guide bush. There is also a problem that occurs.
Therefore, the hard carbon (DLC) film 15 described above is provided on the inner peripheral surface 11 b of the guide bush 11. The film thickness of the hard carbon film 15 is 1 μm to 5 μm.
[0041]
Further, the inner peripheral surface vicinity portion 11h of the end surface 11h where the inner peripheral surface 11b of the guide bush 11 opens. ₁ Also, a hard carbon film is formed in a ring shape.
In the example of FIG. 1, the hard carbon film 15 is formed on the base material (alloy tool steel) of the guide bush 11 directly or via an intermediate layer described later.
[0042]
In the example shown in FIG. 3, a cemented carbide member 12 having a thickness of 2 mm to 5 mm containing at least tungsten (W), carbon (C), and cobalt (Co) is disposed on the inner peripheral surface 11 b of the guide bush 11. The hard carbon film 15 is formed on the inner peripheral surface of the cemented carbide member 12 and the end surface 12a where the inner peripheral surface opens.
[0043]
Further, in the example shown in FIG. 4, the inner peripheral surface 11 b of the guide bush 11 and the inner peripheral surface vicinity portion 11 h of the end surface 11 h where the inner peripheral surface opens. ₁ Is provided with a carburized layer 11k, and a hard carbon film 15 is formed on the carburized layer 11k.
This hard carbon film has properties very similar to diamond. That is, it has features such as high mechanical strength, low friction coefficient, lubricity, good electrical insulation, high thermal conductivity, and excellent corrosivity.
[0044]
Therefore, the inner peripheral surface vicinity portion 11h of the inner peripheral surface 11b and the end surface 11h. ₁ The guide bush 11 provided with the hard carbon film 15 has a significantly improved wear resistance, and suppresses the wear of the inner peripheral surface 11b in contact with the workpiece 51 even during long-term use or heavy cutting. be able to. In addition, it is possible to suppress the occurrence of scratches on the inner peripheral surface of the workpiece 51 and the guide bush 11 and the edge of the opening thereof, and the occurrence of seizure between the guide bush 11 and the workpiece 51 is greatly suppressed. You can also.
[0045]
Therefore, the guide bush 11 according to the present invention can remarkably improve the reliability for long-term use, and can be sufficiently used for a fixed guide bush device.
Here, the inner peripheral surface 11b of the guide bush 11 and the inner peripheral surface vicinity portion 11h of the end surface 11h. ₁ Various configuration examples of the portion provided with the hard carbon film 15 will be described with reference to FIGS.
[0046]
5 to 7 correspond to enlarged views of part A in FIG. 1, and FIG. 5 shows the inner peripheral surface 11b of the guide bush 11 and the inner peripheral surface vicinity portion 11h of the end surface 11h. ₁ The hard carbon film is directly formed on the base material (alloy tool steel) with a film thickness of 1 μm to 5 μm.
[0047]
FIG. 6 shows the inner peripheral surface 11b of the guide bush 11 and the inner peripheral surface vicinity portion 11h of the end surface 11h. ₁ The hard carbon film 15 is formed with a film thickness of 1 μm to 5 μm on the base material through an intermediate layer 16 for improving the adhesion to the hard carbon film 15.
The intermediate layer 16 is made of silicon (Si) or germanium (Ge), which is an element of Group IVb of the periodic table, or a compound of silicon or germanium. Further, a compound containing carbon such as silicon carbide (SiC) or titanium carbide (TiC) may be used.
[0048]
In FIG. 7, the intermediate layer 16 is formed of a two-layer film of a lower layer 16a made of titanium (Ti) or chromium (Cr) and an upper layer 16b made of silicon carbide (SiC).
In this case, titanium or chromium in the lower layer 16a plays a role of maintaining adhesion to the base material of the guide bush 11, and silicon carbide (SiC) in the upper layer 16b is covalently bonded to the hard carbon film. It plays a role of strongly bonding to the membrane.
[0049]
This is because titanium (Ti) and chromium (Cr) have a high adhesion to the alloy tool steel constituting the guide bush 11, and silicon and carbon constituting the silicon carbide (SiC) are both periodic. This is because there is an element belonging to Group IVb in the Table, and the hard carbon film is also composed of carbon, both of which have a diamond structure, so that both films are bonded with high adhesion.
[0050]
8 to 10 correspond to enlarged views of part A in FIG. 3, both of which are formed by brazing a carbide member 12 having a thickness of 2 mm to 5 mm on the base material of the inner peripheral surface 11 b of the guide bush 11. The hard carbon film 15 is formed on the inner peripheral surface 12b and the end surface 12a on the opening side. In this way, the durability of the guide bush 11 is further improved.
[0051]
In the example shown in FIG. 9, the hard carbon film 15 is formed on the inner peripheral surface 12 b and the end surface 12 a of the cemented carbide member 12 via the intermediate layer 16 that further improves the adhesion. The intermediate layer 16 is made of, for example, tungsten carbide (WC).
[0052]
In the example shown in FIG. 10, the intermediate layer 16 is formed of a two-layer film of a lower layer 16a made of titanium (Ti) or chromium (Cr) and an upper layer 16b made of silicon carbide (SiC).
Alternatively, the lower layer 16a of the intermediate layer 16 may be formed of tungsten carbide, and the upper layer 16b may be formed of silicon carbide.
[0053]
In these examples, a cemented carbide member containing at least tungsten, carbon, and cobalt is used as the cemented carbide member 12 provided in the lower layer of the hard carbon film 15. For example, tungsten (W) having a composition of 85% to 90%, carbon (C) of 5% to 7%, and cobalt (Co) of 3% to 10% as a binder is used.
[0054]
In addition, a sintered body of cemented carbide such as tan tag stainless steel (WC) or ceramics such as silicon carbide (SiC) can also be used. When sintering ceramics, chromium (Cr), nickel (Ni), cobalt (Co), or the like is usually added as a binder. If the amount of addition is small, the intermediate layer 16 is formed as shown in FIG. The hard carbon film 15 can also be formed directly on the hard member 12 without intervention.
[0055]
However, as described above, when the hard carbon film 15 is directly formed on the cemented carbide, it is adversely affected by the binder or the like (particularly cobalt (Co)) used to form the cemented carbide, and the hard carbon film 15 is peeled off. There are things to do.
Therefore, as shown in FIG. 9 or FIG. 10, it is preferable to form an intermediate layer 16 that enhances adhesion between the cemented carbide member 12 and the hard carbon film 15.
[0056]
By forming the hard carbon film 15 through the intermediate layer 16, there is no direct contact with the binder of the cemented carbide member 12, and no adverse effect is caused, so that the hard carbon film 15 can be prevented from peeling off.
[0057]
FIGS. 11 to 13 correspond to enlarged views of part A in FIG. 4, and instead of providing the carbide member 12 on the inner peripheral surface 11 b of the guide bush 11, the carburized layer 11 k is formed on the base material near the inner peripheral surface 11 b. The inner peripheral surface 11b of the inner peripheral surface 11b and the end surface 11h formed with the carburized layer 11k are formed. ₁ An example in which the hard carbon film 15 is formed is shown.
[0058]
Carburization is one of the surface hardening methods for steel materials, and is a well-known process that hardens the surface layer and keeps the deep portion tough.
Here, for example, methane (CH ₄ ) Or ethylene (C ₂ H ₄ ) And other carbon-containing carburizing gases and nitrogen (N ₂ The carburization process is performed under the following conditions in a mixed gas atmosphere with the carrier gas.
[0059]
(Carburizing conditions)
Temperature 1100 ° C
30 minutes
Carburization depth 0.5mm
[0060]
Thus, when the carburized layer 11k is formed on the surface of the inner peripheral surface 11b of the guide bush 11, the hard carbon film 15 can be directly formed on the surface as shown in FIG. Alternatively, as shown in FIG. 13, it is more preferable to form an intermediate layer 16 that further enhances adhesion on the surface and to form a hard carbon film 15 via the intermediate layer 16.
[0061]
As the intermediate layer 16, as described above, silicon (Si) or germanium (Ge) of group IVb of the periodic table, or a compound of silicon or germanium can be used.
Further, as shown in FIG. 13, the intermediate layer 16 may be formed in a two-layer film of a lower layer 16a made of titanium (Ti) or chromium (Cr) and an upper layer 16b made of silicon carbide (SiC). .
[0062]
In this case, titanium or chromium in the lower layer 16a of the intermediate layer 16 plays a role of maintaining the adhesion to the base material of the guide bush 11, and the silicon carbide of the upper layer 16b is covalently bonded to the hard carbon film 15, It plays a role of strongly bonding with the hard carbon film 15 and can prevent peeling of the hard carbon film.
[0063]
[Description of Method for Forming Intermediate Layer: FIG. 14]
Next, the inner peripheral surface 11b of the guide bush 11 and the inner peripheral surface vicinity portion 11h of the end surface 11h. ₁ Next, a method for forming the above-described intermediate layer 16 will be described.
As a method for forming the intermediate layer, a sputtering method, an ion plating method, a chemical vapor deposition (CVD) method, or a thermal spraying method can be used.
[0064]
As an example, a method for forming an intermediate layer by sputtering will be described with reference to FIG.
A target cover 96 is provided inside one wall surface 91a of a vacuum chamber 91 having a gas inlet port 93 and an exhaust port 95, and a target 90, which is an intermediate layer material, is disposed there. And the guide bush 11 is arrange | positioned so that this target 90 and the end surface 11h may oppose. At this time, the guide bush 11 is arranged so that the axis of the center opening 11 j is perpendicular to the surface of the target 90.
[0065]
Further, the inner peripheral surface vicinity portion 11h of the end surface 11h of the guide bush 11 ₁ A cover member 94 such as an aluminum foil is wound so as to cover the outer peripheral surface except for.
The guide bush 11 is connected to a DC power source 92, and the target 90 is connected to a target power source 97.
[0066]
After setting in this way, the degree of vacuum in the vacuum chamber 91 is 3 × 10 − ⁵ The exhaust port 95 is evacuated so that it becomes less than torr (0.004 Pa).
Thereafter, argon (Ar) gas is introduced as a sputtering gas from the gas inlet 93, and the degree of vacuum in the vacuum chamber 91 is 3 × 10 −. ³ Adjust to be torr (0.4 Pa).
A negative DC voltage of minus 600 V is applied to the guide bush 11 from the direct current power source 92, and a negative DC voltage of minus 50 V is applied to the target 90 from the target power source 97.
[0067]
Then, plasma is generated in the vacuum chamber 91, and the surface of the target 90 is sputtered by ions in the plasma. Thereby, the material of the intermediate layer struck out from the surface of the target 90 adheres to the portion of the guide bush 11 that is not covered with the cover member 94, and the inner peripheral surface 11b and the end surface 11h in the vicinity of the inner peripheral surface. 11h ₁ The intermediate layer 16 described above can be formed only on the top.
[0068]
Alternatively, in the case of a guide bush in which the carbide member 12 is provided on the inner peripheral surface 11b, the intermediate layer 16 is provided on the inner peripheral surface 12b and the end surface 12a of the carbide member 12 as shown in FIGS. Can be formed.
The intermediate layer 16 is formed to have a film thickness of about 0.5 μm. However, in the case of two layers, both the upper layer and the lower layer are about 0.5 μm.
[0069]
In the case of forming one intermediate layer, silicon carbide (SiC) or tungsten carbide (WC) is used as the target 90. When forming a two-layered intermediate layer, sputtering is first performed using titanium (Ti) or chromium (Cr) as the target 90 to form a lower layer of the intermediate layer, and then silicon carbide ( Sputtering is performed using (SiC) to form the upper layer of the intermediate layer.
[0070]
[Description of Method for Forming Hard Carbon Film]
Next, a method for forming a hard carbon film on the guide bush will be described with reference to FIGS.
First, a method for creating the guide bush 11 before forming the hard carbon film will be briefly described.
[0071]
Cutting is performed using alloy tool steel (SKS), and the outer peripheral tapered surface 11a, the spring portion 11d, the fitting portion 11e, the screw portion 11f, the inner peripheral surface 11b by the central opening 11j, and the step portion having a larger inner diameter than that. 11 g.
Then, electric discharge machining is performed to form slits 11c at 120 ° intervals on the outer peripheral tapered surface 11a side of the guide bush 11.
Further, polishing is performed to polish the inner peripheral surface 11b, the outer peripheral tapered surface 11a, and the fitting portion 11e to obtain the guide bush 11 before forming the hard carbon film.
[0072]
If necessary, the cemented carbide member 12 is fixed to the inner peripheral surface 11b of the guide bush 11 or the carburized layer 11k is formed.
In addition, the inner peripheral surface of the guide bush 11 and the inner peripheral surface vicinity portion 11h of the end face by the above-described method. ₁ Alternatively, the intermediate layer 16 is formed in advance on the inner peripheral surface 12 b and the end surface 12 a of the cemented carbide member 12.
[0073]
(First method: FIGS. 15 and 16)
FIG. 15 is a cross-sectional view of an apparatus for carrying out a first method for forming a hard carbon film on a guide bush.
[0074]
In FIG. 15, reference numeral 61 denotes a vacuum chamber having a gas inlet 63 and an exhaust port 65, and an anode 79 and a filament 81 are arranged at the upper center of the vacuum chamber. The above-described guide bush 11 is vertically arranged with the lower part fixed to the insulating support 80 at the center lower part in the vacuum chamber 61.
[0075]
A thin rod-shaped auxiliary electrode 71 connected to the ground potential via the vacuum chamber 61 is inserted into the central opening 11j of the guide bush 11. At this time, the auxiliary electrode 71 is positioned at the center (substantially on the axis) of the center opening 11j of the guide bush 11. The auxiliary electrode 71 is made of a metal material such as stainless steel.
[0076]
Further, a ring-shaped dummy member 53 having an opening 53a having a diameter approximately 2 mm larger than the diameter of the inner peripheral surface 11b of the guide bush 11 is centered on the end surface 11h where the inner peripheral surface 11b of the guide bush 11 opens. Arranged so as to coincide with the center of the central opening 11j, the inner peripheral surface vicinity portion 11h of the end surface 11h ₁ Is exposed in an annular shape. The appearance of the dummy member 53 is shown in FIG. The dummy member 53 is also formed of stainless steel (SUS), like the auxiliary electrode 71. The outer diameter of the dummy member 53 is approximately the same as the size of the end surface 11 of the guide bush 11.
[0077]
It is desirable that the auxiliary electrode 71 is disposed so as to be positioned on the inner side by about 1 mm to 2 mm so that the tip thereof does not protrude from the upper end surface of the dummy member 53. Further, by covering the outer peripheral surface of the guide bush 11 with a cover member 84 such as an aluminum foil, it is possible to prevent a hard carbon film from being formed on the outer peripheral surface.
[0078]
The degree of vacuum in the vacuum chamber 61 is 3 × 10 −. ⁵ The exhaust port 65 is evacuated so that it becomes torr (0.004 Pa).
Thereafter, benzene (C ₆ H ₆ ) Is introduced into the vacuum chamber 61 and the pressure in the vacuum chamber 61 is reduced to 5 × 10 −. ³ Control to be torr (0.6666 Pa).
[0079]
Thereafter, a minus 3 kV DC voltage is applied to the guide bush 11 from the DC power source 73, a plus 50 V DC voltage is applied to the anode 79 from the anode power source 75, and a current from the filament power source 77 to 30 A is applied to the filament 81. An alternating voltage of about 10V is applied so that it flows.
Thereby, plasma is generated in the peripheral region of the guide bush 11 in the vacuum chamber 61, and the exposed inner peripheral surface 11b and the end surface 11h of the inner peripheral surface 11h of the guide bush 11 are exposed by the plasma CVD process. ₁ A hard carbon film is formed only on the surface.
[0080]
In the method of forming the hard carbon film shown in FIG. 15, by providing the auxiliary electrode 71 so as to be inserted into the central opening 11j of the guide bush 11, not only the outer periphery of the guide bush 11 but also the inner periphery is plasma. Can be formed.
Further, this prevents the occurrence of hollow discharge, which is abnormal discharge, and improves the adhesion of the hard carbon film 15.
[0081]
Further, since the potential characteristics are uniform in the longitudinal direction of the inner peripheral surface of the guide bush 11, the film thickness distribution of the hard carbon film formed on the inner peripheral surface 11b is uniform. In addition, since the film forming speed is increased, a hard carbon film having a uniform film thickness can be formed in a short time from the opening end face side to the opening back side.
[0082]
The diameter of the auxiliary electrode 71 may be smaller than the opening diameter of the guide bush 11, but preferably a gap of about 5 mm, that is, a plasma formation region is provided with respect to the inner peripheral surface 11b forming the hard carbon film. Is desirable. The ratio of the diameter of the auxiliary electrode 71 to the opening diameter of the guide bush 11 is desirably 1/10 or less. When the auxiliary electrode 71 is thinned, it can be linear.
The auxiliary electrode 71 has been described as being formed of stainless steel, but may be formed of a high melting point metal material such as tungsten (W) or tantalum (Ta). The auxiliary electrode 71 has a circular cross section.
[0083]
Further, the dummy member 53 used in this embodiment has the following operation.
That is, in such a method of forming a hard carbon film on the guide bush 11, plasma is generated on the inner surface and the outer peripheral portion of the guide bush 11. And the electric charge tends to concentrate on the end face of the guide bush 11, and the open end face region has a higher potential than the inner face, that is, the so-called edge effect occurs. Here, the plasma intensity in the vicinity of the end face of the guide bush 11 is larger than other regions and is also unstable.
[0084]
Further, the end region of the guide bush 11 is affected by both the inner surface plasma and the outer periphery plasma.
When the hard carbon film is formed in such a state, the adhesion of the hard carbon film is slightly different and the film quality is also slightly different in the region several mm deeper from the end surface 11h of the guide bush 11 and the other region.
[0085]
Therefore, as shown in FIG. 15, if the hard carbon film is formed by arranging the dummy member 53 on the end surface 11 h where the inner peripheral surface 11 b of the guide bush 11 is opened, the regions having different film quality and adhesion are different from each other in the guide bush 11. Is formed on the inner surface of the opening 53 a of the dummy member 53.
[0086]
When the opening diameter of the inner peripheral surface 11b of the guide bush 11 is reduced to about 10 mm or less, the plasma formed between the auxiliary electrode 71 and the inner peripheral surface 11b of the guide bush becomes unstable over time. Therefore, there is a problem that a hard carbon film cannot be formed.
[0087]
This plasma instability can be prevented by inducing plasma in the opening 53 a of the dummy member 53 having an opening diameter larger than the opening diameter of the inner peripheral surface 11 b of the guide bush 11.
This is because plasma can always be stably generated in the opening 53a of the dummy member 53 larger than the opening diameter of the inner peripheral surface 11b of the guide bush.
[0088]
An annular inner peripheral surface vicinity portion 11 h exposed in the opening 53 a of the dummy member 53 on the end surface of the guide bush 11 by the plasma generated in the opening 53 a of the dummy member 53. ₁ In addition, a stable hard carbon film can be formed. Further, the plasma generated at the opening 53a of the dummy member 53 can be introduced into the central opening 11j of the guide bush 11 to form a stable hard carbon film on the inner peripheral surface 11b.
[0089]
As a result, the edge of the workpiece that occurs when machining with a cutting tool is performed in the cutting process of drawing the processed region of the workpiece into the guide bush and gripping the workpiece, which has been a problem in the past. The problem that scratches are generated on the inner peripheral surface of the guide bush 11 due to the burr of the portion can be significantly suppressed.
[0090]
(Second method: FIG. 17)
Next, a second method different from the above-described method for forming the hard carbon film on the guide bush will be described with reference to FIG.
FIG. 17 is a sectional view of an apparatus for carrying out the second method. In FIG. 17, portions corresponding to those in FIG. 15 are denoted by the same reference numerals, and description thereof is omitted.
The vacuum chamber 61 of the apparatus used for the second method is not provided with an anode and a filament therein.
[0091]
The hard carbon film forming method using this apparatus is different from the first method using the apparatus shown in FIG. 15 in that an auxiliary electrode 71 grounded is inserted into the vacuum chamber 61 and arranged. A high-frequency power is applied from a high-frequency power source 69 having an oscillation frequency of 13.56 MHz to the guide bush 11 on which the dummy member 53 is disposed via the matching circuit 67, and methane ( CH ₄ ) The gas is introduced into the inside 4 of the vacuum chamber 61 and only the point that the degree of vacuum is adjusted to 0.1 torr (13.3322 Pa).
[0092]
Even in this case, plasma is generated not only on the outer peripheral surface side of the guide bush 11 but also on the inner peripheral surface side, and the inner peripheral surface 11b of the guide bush 11 and the inner peripheral surface vicinity portion 11h of the end surface thereof by the plasma CVD process. ₁ A hard carbon film is formed. In particular, the hard carbon film 15 having a substantially uniform film thickness can be formed in a short time on the inner peripheral surface 11 b facing the auxiliary electrode 71.
[0093]
(Third method: FIG. 18)
Next, a third method different from the above-described method for forming the hard carbon film on the guide bush will be described with reference to FIG.
FIG. 18 is a sectional view of an apparatus for carrying out the third method. In FIG. 18 as well, portions corresponding to those in FIG. 15 are assigned the same reference numerals, and descriptions thereof are omitted.
The apparatus used for this third method also does not have an anode and filament in the vacuum chamber 61.
[0094]
The hard carbon film forming method using this apparatus is different from the first method using the apparatus shown in FIG. 15 in that an auxiliary electrode 71 grounded is inserted into the vacuum chamber 61 and arranged. Only the minus 600V DC voltage is applied from the DC power source 73 'to the guide bush 11 on which the dummy member 53 is disposed, and methane (CH ₄ It is only the point that the gas is introduced into the vacuum chamber 61 and the degree of vacuum is adjusted to 0.1 torr (13.3322 Pa).
[0095]
Even in this case, plasma is generated not only on the outer peripheral surface side of the guide bush 11 but also on the inner peripheral surface side, and the inner peripheral surface 11b of the guide bush 11 and the inner peripheral surface vicinity portion 11h of the end surface thereof by the plasma CVD process. ₁ A hard carbon film is formed. In particular, the hard carbon film 15 having a substantially uniform film thickness can be formed in a short time on the inner peripheral surface 11 b facing the auxiliary electrode 71.
[0096]
Each of these hard carbon film forming methods can be similarly applied to the formation of the hard carbon film 15 having various layer configurations on the guide bush 11 described with reference to FIGS.
Furthermore, in the method for forming a hard carbon film on the guide bush according to each of the above-described embodiments, it has been described that methane gas or benzene gas is used as the gas containing carbon. However, in addition to methane, a gas containing carbon such as ethylene, hexane, etc. It is also possible to use a liquid vapor containing carbon.
[0097]
(Fourth to sixth methods: FIGS. 19, 20, and 21)
Next, fourth to sixth methods for forming a hard carbon film on the guide bush will be described with reference to FIGS.
[0098]
FIGS. 19 to 21 are diagrams showing apparatuses for carrying out the fourth to sixth methods, respectively. The same apparatuses as those shown in FIGS. 15, 17, and 18 are used. In this example, a hard carbon film is formed on the guide bush 11. Therefore, the same reference numerals are given to the same portions as those of those drawings, and the description thereof is omitted.
[0099]
The fourth method using the apparatus of FIG. 19, the fifth method using the apparatus of FIG. 20, and the sixth method using the apparatus of FIG. 21 differ from the first, second, and third methods described above in the auxiliary method. The insulator 71 supports the electrode 71 with respect to the guide bush 11 and the vacuum layer 61 by a insulator 85 fitted into the central opening 11j of the guide bush 11, and the auxiliary electrode 71 is connected to the direct current positive electrode 83 from the auxiliary electrode power source 83. This is a point where a voltage (for example, plus 20 V) is applied.
[0100]
The relationship between the positive DC voltage applied to the auxiliary electrode 71 and the film thickness of the hard carbon formed on the inner surface of the guide bush 11 is shown in the diagram of FIG.
In this figure, the hard carbon film when the DC positive voltage applied to the auxiliary electrode 71 is changed from zero V to 30 V and the gap between the opening inner surface of the guide bush 11 and the auxiliary electrode 71 is 3 mm and 5 mm. The film thickness is shown. Curve a shows the characteristics when the gap is 3 mm, and curve b shows the characteristics when the gap is 5 mm.
[0101]
As shown by the curves a and b, when the positive DC voltage applied to the auxiliary electrode 71 is increased, the film formation rate of the hard carbon film is improved. In addition, the larger the gap dimension 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.
[0102]
When the gap between the opening inner surface of the guide bush 11 and the auxiliary electrode 71 is 3 mm (curve a), the center opening 11j of the guide bush 11 is applied at the ground voltage with a potential applied to the auxiliary electrode 71 of zero V. No plasma is generated on the inner surface of the film, and a hard carbon film cannot be formed.
However, even in this case, if the DC positive voltage applied to the auxiliary electrode 71 is increased, plasma is generated around the auxiliary electrode 71 in the central opening 11j of the guide bush 11 and a hard carbon film can be formed. .
[0103]
Therefore, according to this embodiment in which a DC positive voltage is applied to the auxiliary electrode 71 on the inner peripheral surface of the guide bush having a small diameter of the central opening 11j, a hard carbon film can be formed.
Such an action is the same even when a hard carbon film is formed on the guide bush 11 by any of the methods shown in FIGS.
[0104]
(Examples of different dummy members: FIGS. 23 to 28)
Here, various examples in which the shape of the opening 53a of the dummy member 53 is different will be described with reference to FIGS.
The dummy member 53 shown in FIG. 23 corresponds to that used in the embodiment shown in FIGS. 15 to 21, and the diameter of the opening 53a is uniformly formed over the entire length in the axial direction.
[0105]
The dummy member 53 shown in FIG. 24 has an opening 53a composed of a large diameter part a and a small diameter part b. The opening diameter of the small diameter portion b is made about 2 mm larger than the opening diameter of the inner peripheral surface 11 b of the guide bush 11, and the opening diameter of the large diameter portion a is made about 2 mm larger than the opening diameter of the small diameter portion b.
[0106]
In the dummy member 53 shown in FIG. 25, the opening 53a is constituted by a large-diameter portion a and a small-diameter portion b, and a tapered portion c between the large-diameter portion a and the small-diameter portion b. The opening diameter of the small diameter portion b is about 2 mm larger than the opening diameter of the inner peripheral surface 11 b of the guide bush 11, and the opening diameter of the large diameter portion a is about 2 mm larger than the opening diameter of the small diameter portion b. The opening diameter of the taper part c is changed gradually.
[0107]
The dummy member 53 shown in FIG. 26 has an opening 53a constituted by a small diameter part b and a taper part c. The opening diameter of the small diameter portion b is set to be about 2 mm larger than the opening diameter of the inner peripheral surface 11 b of the guide bush 11, and the maximum diameter of the tapered portion c is configured to be about 2 mm to 5 mm larger than the opening diameter of the small diameter portion b. To do.
[0108]
In the dummy member 53 shown in FIG. 27, the opening 53a is constituted only by the tapered portion c. The minimum opening diameter of the tapered portion is set to be about 2 mm larger than the opening size of the inner peripheral surface 11 b of the guide bush 11, and the maximum opening diameter is set to be about 2 mm to 5 mm larger than the minimum opening diameter.
[0109]
The dummy member 53 shown in FIG. 28 has an opening 53a composed of a large diameter part a, a medium diameter part d, and a small diameter part b. The opening diameter of the small diameter portion b is made about 2 mm larger than the opening diameter of the inner peripheral surface 11b of the guide bush 11, and the opening diameter of the large diameter portion a is made about 2 mm to 5 mm larger than the opening diameter of the small diameter portion b. The medium diameter part d is the opening diameter between the large diameter part a and the small diameter part b. That is, in the dummy member 53, the opening 53a has a stepped cross section.
[0110]
The dummy member 53 shown in FIGS. 24 to 28 is different from the dummy member 53 shown in FIG. 23 in that the opening 53a has a tapered portion c or a step-like cross-sectional shape. Therefore, as compared with the dummy member 53 shown in FIG. 23, it is possible to smoothly introduce the plasma into the peripheral region of the auxiliary electrode 71 in the central opening 11j of the guide bush 11.
Therefore, it becomes possible to generate plasma more stably in the peripheral region of the auxiliary electrode 71 in the central opening 11j of the guide bush 11, and the hard carbon film can be formed more stably.
[0111]
(Supplementary explanation)
Each of the hard carbon film forming methods described above can be similarly applied to the formation of the hard carbon film 15 having various layer configurations on the guide bush 11 described with reference to FIGS.
Further, in each of these film forming methods, the outer peripheral portion of the guide bush 11 is covered with the cover member 84 so that the hard carbon film is not formed on the outer peripheral surface of the guide bush 11. Further, the inner peripheral surface vicinity portion 11h of the end surface 11h ₁ Since the other area is covered with the dummy member 53, the hard carbon film is not formed.
[0112]
As a result, there is an advantage that the outer dimensions of the guide bush 11 can be maintained with high accuracy, and that the toughness of the portion of the outer peripheral tapered surface 11a on which the slit 11c is formed can be prevented.
However, even if a hard carbon film is formed on the outer peripheral surface of the guide bush 11 without using the cover member 84, no significant problem occurs.
[0113]
In the method for forming a hard carbon film on the guide bush according to each of the embodiments described above, methane (CH ₂ ) Or benzene (C ₆ H ₆ ), But ethylene (C ₂ H ₄ ) Or hexane (C ₆ H ₁₄ ) Etc. can also be used.
[0114]
Furthermore, these carbon-containing gases can be diluted with an inert gas having a low ionization voltage such as argon (Ar). In that case, there is an effect that the plasma in the cylinder of the guide bush is further stabilized.
Alternatively, lubricity and hardness can be improved by adding a small amount (1% or less) of an additive during the formation of the hard carbon film.
[0115]
For example, the addition of fluorine (F) or boron (B) increases the lubricity, and the addition of chromium (Cr), molybdenum (Mo) or tungsten (W) increases the hardness.
In addition, after arranging the guide bush in the vacuum chamber, before forming the hard carbon film, argon (Ar) or nitrogen (N ₂ ) Or the like to bombard the cylindrical inner surface of the guide bush, and then a plasma with a gas containing carbon such as methane or benzene is generated to form a hard carbon film.
[0116]
Thus, by performing the pretreatment of the bombardment with the inert gas, the temperature of the cylindrical inner wall of the guide bush rises and becomes an active state. At the same time, impurities on the surface of the cylinder inner wall are knocked out and the surface is cleaned. Due to these effects, the adhesion of the hard carbon film formed on the inner peripheral surface of the guide bush is further improved.
Furthermore, methane gas, benzene gas, and ethylene gas, which are carbon-containing gases, are added to argon (Ar) gas and nitrogen (N ₂ ) Gas, helium (He) gas, hydrogen (H ₂ ) Gas may be added.
[0117]
Thus, when argon gas or nitrogen gas is added to the gas containing carbon, the film formation rate can be controlled. Therefore, the hard carbon film can be densified, and the hard carbon film surface can be sputtered with nitrogen or argon to remove the hard carbon film with poor adhesion and film quality, and the film quality is improved. Furthermore, when hydrogen is added to a gas containing carbon, dangling bonds of carbon can be filled with hydrogen, and the film quality of the hard carbon film is improved.
[0118]
And in description of embodiment in the formation method of the hard carbon film of this invention demonstrated above, 11 h of inner peripheral surface vicinity parts of the end surface of the guide bush 11 ₁ In the embodiment, the hard carbon film is provided by extending about 1 mm from the boundary area between the inner peripheral surface and the end surface portion. However, the present invention is not limited thereto, and the hard carbon film may be formed to a size of 1 mm or more. Good.
[0119]
Further, the example has been described in which the minimum diameter of the opening 53a of the dummy member 53 is about 2 mm larger than the opening diameter of the inner peripheral surface 11b of the guide bush 11. However, the diameter of the opening 53 a of the dummy member 53 may be 3 mm to 6 mm larger than the opening diameter of the inner peripheral surface 11 b of the guide bush 11. Also at this time, the opening 53a of the dummy member 53 performs the same operation as in the above-described embodiment, and a similar effect is obtained.
[0120]
Further, in the above description of the embodiment, the dummy member 53 is described as having an opening 53a larger than the opening diameter of the inner peripheral surface 11b as a measure against instability of plasma discharge.
However, the present invention is applied to the guide bush 11 having an opening diameter of the inner peripheral surface 11b of 10 mm or more for the purpose of stabilizing the discharge of plasma formed between the auxiliary electrode 71 and the inner peripheral surface 11b of the guide bush 11. May be.
[0121]
【The invention's effect】
As described above, the guide bush according to the present invention in which a hard carbon film is provided in the vicinity of the inner peripheral surface of the inner peripheral surface in sliding contact with the workpiece and the end surface on the side where the workpiece is inserted is used as a rotary type of an automatic lathe or By using it in a fixed guide bushing device, it is possible to prevent scratches on the inner peripheral surface of the guide bush due to burrs on the work piece, and to generate a large amount of cut on the work piece. It is possible to carry out the process normally without causing a problem, and the processing efficiency can be greatly increased.
[0122]
In addition, due to the significant improvement in durability, the time for continuous machining becomes longer, and the operating efficiency of automatic lathes is dramatically improved. Moreover, by using it for a fixed guide bushing device, cutting with high machining accuracy (particularly roundness) can be performed efficiently.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an example of a guide bush according to the present invention.
FIG. 2 is a perspective view showing the appearance of the same.
FIG. 3 is a longitudinal sectional view showing another example of the guide bush according to the present invention.
FIG. 4 is a longitudinal sectional view showing still another example of the guide bush according to the present invention.
5 is an enlarged cross-sectional view corresponding to a portion surrounded by a circle A in FIG.
FIG. 6 is an enlarged cross-sectional view showing an example in which one intermediate layer is provided.
FIG. 7 is an enlarged sectional view showing an example in which two intermediate layers are provided.
8 is an enlarged cross-sectional view corresponding to a portion surrounded by a circle A in FIG.
FIG. 9 is an enlarged cross-sectional view showing an example in which one intermediate layer is provided.
FIG. 10 is an enlarged cross-sectional view showing an example in which two intermediate layers are provided.
11 is an enlarged cross-sectional view corresponding to a portion surrounded by a circle A in FIG.
FIG. 12 is an enlarged cross-sectional view showing an example in which the single intermediate layer is provided.
FIG. 13 is an enlarged sectional view showing an example in which two intermediate layers are provided.
FIG. 14 is a cross-sectional view of an apparatus for explaining an example of a method for forming an intermediate layer on a guide bush.
FIG. 15 is a schematic sectional view of an apparatus for carrying out a first method for forming a hard carbon film on a guide bush.
16 is a perspective view of the dummy member shown in FIG.
FIG. 17 is a schematic sectional view of an apparatus for carrying out a second method for forming a hard carbon film on the guide bush.
FIG. 18 is a schematic cross-sectional view of an apparatus that similarly performs the third method.
FIG. 19 is a schematic cross-sectional view of an apparatus that similarly performs the fourth method.
FIG. 20 is a schematic cross-sectional view of an apparatus that similarly performs the fifth method.
FIG. 21 is a schematic cross-sectional view of an apparatus that similarly performs the sixth method.
FIG. 22 is a diagram showing the relationship between the positive DC voltage applied to the auxiliary electrode and the thickness of the hard carbon film to be formed.
FIG. 23 is an enlarged longitudinal sectional view of a main part showing a state in which a dummy member is arranged on an end face of a guide bush into which an auxiliary electrode is inserted.
24 is a cross-sectional view similar to FIG. 23 in which a dummy member having an inner peripheral surface shape different from that of the dummy member shown in FIG. 23 is arranged.
25 is a cross-sectional view similar to FIG. 23 in which dummy members having different inner peripheral surfaces are arranged.
26 is a cross-sectional view similar to FIG. 23 in which dummy members having different inner peripheral surfaces are arranged.
FIG. 27 is a cross-sectional view similar to FIG. 23 in which dummy members having different inner peripheral surfaces are arranged.
FIG. 28 is a cross-sectional view similar to FIG. 23 in which dummy members having different inner peripheral surfaces are arranged.
FIG. 29 is a cross-sectional view showing only the vicinity of the main spindle of an automatic lathe provided with a fixed guide bushing device using the guide bushing according to the present invention.
FIG. 30 is a cross-sectional view showing only the vicinity of the main axis of an automatic lathe provided with a rotary type guide bush device using a guide bush according to the present invention.
[Explanation of symbols]
11: Guide bush 11a: Peripheral taper surface
11b: Inner peripheral surface in sliding contact with the workpiece
11c: slitting 11e: fitting part
11f: Screw part 11g: Step part
11h: End face 11h ₁ : End surface vicinity of inner peripheral surface
11j: Center opening 11k: Carburized layer
12: Carbide member 13: Collet chuck
15: Hard carbon (DLC) film 16: Intermediate layer
16a: Lower layer of the intermediate layer 16b: Upper layer of the intermediate layer
17: Main spindle 19: Main spindle
23: Bush sleeve 29: Intermediate sleeve
31: Chuck opening / closing mechanism 33: Chuck opening / closing claw
35: Column 37: Guide bushing device
41: Chuck sleeve 45: Cutting tool (blade)
47: Rotation drive rod 51: Work piece (workpiece)
53: Dummy member 53a: Dummy member opening
61: Vacuum tank 63: Gas inlet 65: Exhaust port
67: Matching circuit 69: High frequency power supply
71: Auxiliary electrode 73, 73 ': DC power supply
75: Anode power supply 77: Filament power supply
79: Anode 80: Insulating support
81: Filament 83: Auxiliary electrode power supply
84: cover member 85: insulator
90: Target (material for intermediate layer) 91: Vacuum chamber
92: DC power supply 93: Gas inlet
94: Cover member 95: Exhaust port
96: Target cover 97: Target power supply

Claims (9)

It is formed in a substantially cylindrical shape having a central opening in the axial direction, and has an outer peripheral tapered surface, an inner peripheral surface that is in sliding contact with the work piece, and a slit at one end, and when mounted on an automatic lathe, A guide bush for holding the inserted workpiece slidably in the rotation and axial direction near the cutting tool,
A guide bush, wherein a hard carbon film made of hydrogenated amorphous carbon is formed in a portion near the inner peripheral surface of an inner peripheral surface formed by the central opening and an end surface where the inner peripheral surface opens. It is formed in a substantially cylindrical shape having a central opening in the axial direction, and has an outer peripheral tapered surface, an inner peripheral surface that is in sliding contact with the work piece, and a slit at one end, and when mounted on an automatic lathe, A guide bush for holding the inserted workpiece slidably in the rotation and axial direction near the cutting tool,
A cemented carbide member containing at least tungsten, carbon, and cobalt is provided on an inner circumferential surface formed by the central opening, and an inner circumferential surface of the cemented carbide member and an end surface of the cemented carbide member that the inner circumferential surface opens. And a hard carbon film made of hydrogenated amorphous carbon. It is formed in a substantially cylindrical shape having a central opening in the axial direction, and has an outer peripheral tapered surface, an inner peripheral surface that is in sliding contact with the work piece, and a slit at one end, and when mounted on an automatic lathe, A guide bush for holding the inserted workpiece slidably in the rotation and axial direction near the cutting tool,
A carburized layer is provided in the vicinity of the inner peripheral surface of the inner peripheral surface formed by the central opening and the end surface where the inner peripheral surface opens, and a hard carbon film made of hydrogenated amorphous carbon is formed on the carburized layer. A guide bush characterized by that. The guide bush according to claim 1,
A guide bush in which the hard carbon film is formed on the inner peripheral surface and an end surface where the inner peripheral surface is open in the vicinity of the inner peripheral surface via an intermediate layer that enhances adhesion to the hard carbon film. The guide bush according to claim 2,
A guide bush in which the hard carbon film is formed on the cemented carbide member through an intermediate layer that enhances adhesion to the hard carbon film. The guide bush according to claim 3,
A guide bush in which the hard carbon film is formed on the carburized layer through an intermediate layer that enhances adhesion to the hard carbon film. The guide bush according to any one of claims 4 to 6, wherein the intermediate layer is formed of a two-layer film including a lower layer made of titanium or chromium and an upper layer made of silicon carbide. The guide bush according to claim 5, wherein the intermediate layer is formed of a tungsten carbide film. The guide bush according to claim 5, wherein the intermediate layer is formed of a two-layer film of a lower layer made of tungsten carbide and an upper layer made of silicon carbide.

Images