JP2002178207A - Fine hole drilling method, tool holder using for the same method and machining center - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fine hole drilling method capable of using a high pressure coolant liquid of about 12 to 14 MPa for fine hole drilling, in a normal machining center. SOLUTION: An attachable/detachable tool holder TH1 mounted with a tool T1 for a fine hole of a small diameter is mounted at a tip 1A of a spindle. Machining is performed by injecting the high pressure coolant liquid C of about 12 to 14 Mpa into a work machining hole H1 from a center through S opened in the tool T1 for the fine hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-hole gun drill machine tool, and more particularly to a small-hole drilling method for efficiently performing a small and deep hole drilling in a machine tool such as a machining center which performs tool change. To a tool holder and a machining center to be used.

[0002]

2. Description of the Related Art Conventionally, a method of forming a fine and deep hole is often performed by using an electric discharge machine. According to this electric discharge machine, the electric discharge machine is expensive and
The processing efficiency is not very good. Therefore, a dedicated machine for a small hole gun drill in which a small hole drill is mounted on a main shaft of a machine tool in order to form a drill hole is known as a typical example.
Processing by this small hole gun drill machine is performed by using a high-pressure coolant liquid (12 to 14 Mp) through a center hole drilled at the center of the tool.
a) is injected into the machining hole, and is performed by a special tool that rotates at a high speed.

[0003] The pressure of the high-pressure coolant liquid in the above-mentioned small hole processing requires a pressure of about 12 Mpa in the case of fine and deep hole processing, for example, when the hole diameter is 1 mm, for cutting performance and chip removal. Such an ultra-high pressure coolant liquid (1
2-14 Mpa) is supplied to a small-hole tool mounted on the tip of a tool holder through a fitting surface (connecting portion) between a tapered portion of a main spindle and a tapered portion of a tool holder in a normal machining center. (Leakage) at the connection. For this reason, the tapered part of the tool holder cannot be completely attached to the taper hole of the main spindle, and there are many problems such as troubles in the tool holder, reduction in machining accuracy of small hole machining, and inability to drill a small hole itself. is there. This is a problem that also occurs in a two-face constraint type tool holder.

[0004] For the above reasons, the machining of small holes has to rely on a dedicated machine tool such as a gun drill machine, and cannot be carried out on a machine tool that automatically changes tool holders like a normal machining center. This cannot meet the recent demand for performing a fine hole drilling with a normal machining center, and there is a problem that a machining center capable of drilling a fine hole must be urgently developed and put into practical use.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned various problems of the conventional small-hole gun drilling machine itself, the method of machining the small hole, and the tool holder used therein. A main object of the present invention is to use a normal machining center to process 12 to 14 M
An object of the present invention is to provide a method for forming a small hole, which enables use of a high-pressure coolant having a pressure of about pa.

Further, another object of the present invention is to provide:
An object of the present invention is to provide a tool holder having a side-through (flange-through) configuration for supplying coolant to a center through of a tool in order to carry out the above-described method for forming a small hole.

[0007]

According to a first aspect of the present invention, there is provided a method for machining a small hole, comprising the steps of: attaching a detachable tool holder having a small-diameter small hole tool attached to a tip of a spindle; It is characterized in that a high-pressure coolant liquid of about 12 to 14 Mpa is injected into the work hole from the center through to work.

[0008] The tool holder used in the method for machining a small hole according to the second aspect of the present invention is characterized in that the tool holder is 12 to
In a tool holder used for a method for forming a small hole by spraying a high-pressure coolant liquid of about 14 Mpa, a contact surface facing a coolant supply connection port provided on a front end surface of a spindle is provided on a flange end surface of the tool holder. It is characterized in that a supply passage of a side through (flange through) serving as a receiving connection port opened in the contact surface is connected to a coolant supply passage leading to a center through of the tool for a fine hole.

According to a third aspect of the present invention, there is provided a tool holder for use in the method for forming a small hole according to the second aspect, wherein the tool holder faces a coolant supply connection port provided on a front end surface of the spindle. The joint is characterized in that the periphery of the receiving connection port opened in the contact surface of the flange end surface is concave.

According to a fourth aspect of the present invention, there is provided a machining center wherein a tool holder having a side through (flange through) of the same standard as a normal tool holder is provided in a tool magazine of an automatic tool changer in a mixed manner or independently, and the side through (flange through) is provided. The present invention is characterized in that, when the tool holder is mounted on the spindle, the coolant supply connection port provided on the front end face of the spindle and the reception connection port provided on the flange end face of the tool holder with side through (flange through) are connected.

According to a fifth aspect of the present invention, there is provided a machining center according to the fourth aspect.
In the machining center described above, the periphery of the coolant supply connection port provided on the front end surface of the spindle is concave, and the periphery of the supply connection port opened on the facing surface of the flange end face of the tool holder with side through (flange through) facing it is It is characterized by being joined as a plane.

[0012]

According to the method for processing a small hole of the first aspect, first,
Pilot holes (preliminary holes for guidance) are drilled in the work in advance using a pilot drill having a small diameter and a short length by a small depth as a guide. Subsequently, a tool holder for a small-diameter small-hole tool is exchangeably mounted on the tip of the spindle. Next, the small hole tool is rotated at a high speed with respect to the pilot hole (preliminary hole for guiding) previously drilled in the work, and 12 to 14 MPa from the center through.
Fine hole processing is performed while spraying the high-pressure coolant liquid before and after.

Thus, the high-pressure coolant is reliably supplied and transmitted from the center through to the deep portion of the small hole to be drilled in the work, and efficient cutting can be performed without causing the shortage of the coolant and the heat generated by the coolant. Further, chips generated from the cutting edge of the small hole tool are reliably and efficiently discharged out of the small hole by a high-pressure coolant liquid of about 12 to 14 Mpa in an extremely small small hole.

According to the tool holder used in the method for machining a small hole according to the second aspect, when the tool holder is mounted on the tip end hole of the spindle,
The contact surface provided on the flange end surface of the tool holder is brought into contact with the coolant supply connection port provided on the front end surface of the spindle. At this time, a coolant supply connection port opened in the contact surface of the spindle,
The receiving connection port provided on the flange end face is joined to form a side through (flange through). The supply passage connected to the receiving connection port of the tool holder is connected to the coolant supply passage connected to the center through of the small hole tool in the tool holder.

According to the above-mentioned tool holder, the coolant supply connection port on the front end face of the spindle and the reception connection port provided on the flange end face of the tool holder are connected in a side-through (flange-through) form. Liquid (12 ~
14Mpa) passes from the coolant supply connection port opened in the contact surface of the main shaft, through the side through (flange through) of the reception connection port provided on the flange end face, and through the supply passage connected to the reception connection port in the tool holder. Leading to the center through of small hole tools. An ultra-high pressure coolant liquid (12 to 14 Mpa) is jetted from the tip of the center through of the small hole tool.

As described above, the ultra-high pressure coolant liquid (12
~ 14Mpa) passes through the side through (flange through) of the receiving connection port provided on the flange end face, so that liquid leakage occurs at the fitting surface (connecting portion) between the main shaft hole and the fitting convex portion of the tool holder. Never. For this reason, the fitting convex portion of the tool holder to the main shaft hole is completely mounted, and it is possible to maintain the processing accuracy of the trouble of the tool holder and the small hole with high accuracy, and is good at processing the small hole itself.

Further, since the tool holder is provided with a receiving connection port for side through (flange through) in addition to a normal flange portion, in a normal machining center, a tool magazine of the same type is provided in a tool magazine. As a tool holder, a tool holder for mounting a small hole tool can be mixed and installed. Therefore, fine hole drilling and normal cutting can be performed in a mixed manner by changing tools, so that fine hole drilling can be performed by a normal machining center without using a dedicated machine tool such as a fine hole gun drill machine.

According to a third aspect of the present invention, there is provided a tool holder used in the method for machining a small hole. The coolant supply connection port is provided on the front end face of the spindle, and the reception connection port is provided on the contact face of the flange end face of the tool holder facing the coolant supply connection port. Is joined as a concave surface, even if the ultrahigh-pressure coolant liquid leaks from the contact surface, the leakage will only occur in a narrow area with the concave surface, and the pressing force will be limited to only the concave surface.

Therefore, the super-high pressure coolant does not leak to the entire peripheral surface of the front end surface of the spindle and the end surface of the flange of the tool holder facing the main shaft, so that the pressing force does not spread. Therefore,
The mounting accuracy of the tool holder with respect to the spindle is maintained at high accuracy, and the processing accuracy is also maintained at high accuracy.

According to the machining center of the present invention, a tool holder with a side through (flange through) of the same standard as that of a normal tool holder is provided in the tool magazine of the automatic tool changer in a mixed manner or independently, and the side through (flange through) is provided. When the tool holder with through-hole is attached to the spindle, the coolant supply connection port provided on the tip end face of the spindle and the receiving connection port provided on the flange end face of the tool holder with side-through (flange-through) are connected. (12 ~
14Mpa) does not occur and small holes can be drilled in a normal machining center while maintaining high precision.

According to the machining center of the present invention, the periphery of the coolant supply connection port provided on the front end face of the main spindle is made concave, and the periphery of the coolant supply connection port is opened on the contact face of the flange end face of the tool holder with side through (flange through) facing the coolant supply connection port. Since the periphery of the receiving connection port is joined as a plane, even if the ultra-high pressure coolant liquid leaks from this confronting surface, the leakage will only leak in a narrow area with the concave surface, and the pressing force will also be limited only to this concave surface Is done.

Therefore, the super-high-pressure coolant does not leak to the entire peripheral surface of the front end surface of the spindle and the end surface of the flange of the tool holder facing the main shaft, so that the pressing force does not spread. Therefore,
The mounting accuracy of the tool holder with respect to the spindle is maintained at high accuracy, and the processing accuracy is also maintained at high accuracy.

[0023]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a method for machining a small hole according to the present invention and a tool holder used in the method. FIG. 1 is a right side view of a machine tool for implementing the method for machining a small hole, FIG. 2 is a cross-sectional view of a spindle and a tool holder,
FIG. 3 is a cross-sectional view of the connection state between the tool holder and the spindle end, and FIG.
Is a perspective view of the spindle tip surface and the flange end surface of the tool holder,
5 and 6 are cross-sectional views of the tool holder, and FIG. 7 is an operation cross-sectional view showing a state of machining a small hole.

In FIG. 1 and FIG. 2, M is a machining center, which is a general machine tool for implementing the method for processing a small hole according to the present invention. HP is an ultra-high pressure coolant generation device, which generates an ultra-high pressure coolant liquid (12 to 14 Mpa). The ultrahigh-pressure coolant liquid (12 to 14 MPa) is connected to the tail end of the drawing bolt 3 inserted through the center hole 2 of the main shaft 1 by a pipe P. The center hole 3A of the drawing bolt 3 is used as a supply conduit, and 2
It moves to the supply line 6 and reaches check valves V1 and V2 built in near the tip of the spindle. The check valves V1 and V2 are opened by the pressure of the ultra-high pressure coolant liquid (12 to 14 Mpa) and closed by the disappearance of the pressure. At the outlet side of the check valves V1 and V2, two tubular coolant supply connection ports 8 are fitted so as to be movable in the axial direction. In addition, 4 in FIG. 1 is a collection pipe for mist generated in the processing area, and 5 is a mist suction device.

As shown in FIGS. 2 and 3, the coolant supply connection port 8 is provided with a large fitting hole φD on the side facing the check valves V1 and V2, and the inner hole 8a is formed with the fitting hole φD. And is continuous. In addition, a small inner hole φd is formed on the tip side protruding from the spindle tip face 1A to the outside. Thereby, when the ultra-high pressure coolant is supplied to the inside, the coolant supply connection port 8 spills out from the inner hole φd to the outside and generates a large propulsive force F generated in the large fitting hole φD.
As a result, the coolant supply connection port 8 is moved toward the tip of the spindle. As shown in FIG. 3 and FIG. 4, the two coolant supply connection ports 8 looking from the front end face 1A of the main shaft are propelled to two confronting faces (concave faces) 10B recessed in the flange end face 10A of the tool holder TH1. Contact with force F. Tool holder TH
1 is also mounted in the hole 1C of the spindle 1 with its flange end face 10A brought into close contact with the spindle tip face 1A.

The tool holder TH1 with a side through (flange through) is of the same standard as a normal tool holder used in a machining center. That is, the flange 10 of the tool holder TH1 is provided with a V-groove ring 10C that is held by the two holding portions H of the tool changing arm. As a result, the tool holder TH1 with the side through (flange through) can be provided in the tool magazine of the automatic tool changer in a mixed manner or independently. And the tool-exchanged side through (flange through)
When the tool holder TH1 is attached to the spindle 1, the spindle tip surface 1
The coolant supply connection port 8 provided in A is connected to the reception connection port provided on the flange end face of the tool holder with side through (flange through).

This connection state is, as shown in FIGS. 2 and 5, the coolant supply connection port 8 opened in the front end face 1A of the main shaft.
And the two receiving connection ports 11 of the two contact surfaces 10B provided on the flange end face 10A are joined to form a side through (flange through) 20. Two supply passages 13 connected to the receiving connection port 11 of the tool holder TH1 are connected in the tool holder to a coolant supply passage 15 connected to the center through S of the small hole tool T1.

The embodiment of the present invention is configured as described above, and operates as follows. First, according to the fine hole drilling method, as shown in FIGS. 5 and 7 (a), a pilot drill PD having a small diameter and a short diameter is previously formed on a work W by a small depth.
Then, a pilot hole (preliminary hole for guiding) h is formed. Subsequently, a tool holder TH for a small-diameter small-hole tool T1 is provided at the tip of the spindle.
Replace with 1 Next, using the pilot hole (preliminary hole for guidance) h previously drilled in the work W as a guide, the small-hole tool T1 is rotated at a high speed, and 12 mm from the center through.
Fine hole drilling is performed while injecting a high-pressure coolant liquid C of about 14 Mpa.

As a result, as shown in FIG. 7B, the high-pressure coolant liquid C is reliably supplied and transmitted from the center through to the deep portion of the small hole H1 drilled in the workpiece W, as shown in the action sectional view of the chip removal. Efficient cutting can proceed without shortage and heat generation due to the shortage. Further, chips e created from the cutting edge t of the small hole tool T1 are reliably and efficiently discharged out of the small hole by the high-pressure coolant liquid C of about 12 to 14 Mpa in the very small small hole H1. You.

The tool holder TH1 used in the above-described method for machining a small hole functions as follows. When the tool holder TH1 is mounted in the spindle tip hole, the contact surface provided on the flange end face 10A of the tool holder is brought into contact with the coolant supply connection port 8 provided on the spindle tip face 1A. At this time,
The coolant supply connection port opened on the contact surface of the main shaft 1 and the reception connection port 11 provided on the flange end face are joined to form a side through (flange through) 20. The supply passage connected to the receiving connection port of the tool holder is connected to the coolant supply passage connected to the center through S of the small hole tool T1 in the tool holder.

Further, according to the tool holder TH1, the coolant supply connection port 8 on the front end face of the spindle and the reception connection port 11 provided on the flange end face 10A of the tool holder are connected in the form of a side through (flange through) 20. Therefore, the ultra-high pressure coolant liquid (12 to 14 Mpa) C passes through the side through (flange through) of the receiving connection port provided on the flange end face from the coolant supply connection port opened in the contact surface of the main shaft 1 and the tool. In the holder, the coolant passes through the supply passage 13 and the coolant supply passage 15 connected to the receiving connection port 11, and reaches the center through S of the small hole tool T1. An ultra-high pressure coolant liquid (1
2-14 Mpa) C is ejected.

As described above, the ultra-high pressure coolant liquid (12
１４14 Mpa) C are receiving connection ports 11, 11 provided in a part of the confronting faces (concave faces) 10 B, 10 B of the flange end face 10 A.
Pass through the side through (flange through) 20 of
As shown in FIGS. 2 to 4, liquid leakage does not occur on the fitting surface (connection portion) 30 between the hole 1C of the main shaft 1 and the fitting projection of the tool holder TH1. For this reason, the fitting protrusion 30 of the tool holder into the spindle hole 1C and the close contact between the spindle tip surface 1A and the flange end surface 10A are mounted in a complete state. Therefore,
It can maintain the machining accuracy of tool holder troubles and small holes with high precision, and is good at machining small holes themselves.

Further, since the tool holder TH1 is provided with the receiving connection port 11 for side through (flange through) on the flange end face 10A having a normal shape, the tool holder TH1 is inserted into the tool magazine in a normal machining center. As the same type of tool holder, a tool holder for mounting the small hole tool T1 can be mixed and installed. Therefore, the fine hole drilling and the normal cutting can be mixed and performed by changing the tool, so that the fine hole drilling can be performed by a normal machining center without relying on a special machine tool such as a fine hole gun drilling machine.

According to the tool holder TH1,
The coolant supply connection port 8 provided on the spindle front end face 1A is joined as a concave surface 10B around the receiving connection port 11 opened at the contact face of the flange end face of the facing tool holder. Even if the high-pressure coolant leaks, the leak is leaked only in a narrow area with the concave surface, and the pressing force F is also limited to only this concave surface. For this reason, the super-high-pressure coolant does not leak over the entire peripheral surface of the main shaft front end surface 1A and the flange end surface 10A of the tool holder TH1 facing the main shaft front end surface 1A, so that the pressing force does not spread. Therefore, the mounting accuracy of the tool holder TH1 with respect to the spindle 1 is maintained with high accuracy, and the processing accuracy is also maintained with high accuracy.

The thin hole machining method of the present invention can be applied to an ordinary machining center by equipping a tool magazine (not shown) with a tool holder TH1 with a side through (flange through). That is, in the machining center, the side through of the same standard as the normal tool holder
A tool holder with (flange through) is installed in the tool magazine of the automatic tool changer (not shown) mixed or alone,
When the tool holder with side through (flange through) is mounted on the spindle 1, the coolant supply connection port 8 provided on the tip end face of the spindle and the receiving connection port 11 provided on the flange end face of the tool holder with side through (flange through) are connected. Because
There is no leakage of the ultra-high pressure coolant liquid (12 to 14 Mpa) C, and it is possible to perform fine hole drilling in a normal machining center while maintaining high precision.

In the above-mentioned machining center, it is possible to mix the small hole machining and the work machining with a normal tool. The specific means is that when the tool holder is replaced with a tool holder having a large-diameter tool (drill of several mm or more), the normal pressure (2
５5 Mpa) of coolant liquid, and normal drilling and other processing are performed. On the other hand, the pressure change of the coolant is performed by the tool number of the tool holder with the side through (flange through) registered in advance in accordance with the tool change command from the NC controller. When it is attached to the, it becomes an ultra-high pressure coolant liquid (12 to 14 Mpa) C.

Therefore, work machining with a normal tool and
With a tool holder with side through (flange through), gun drilling of small holes with ultra-high pressure coolant can be performed efficiently with a single machining center.

The present invention is not limited to the above embodiment. For example, the tool holder TH1 can be implemented in a tool holder in which the tapered shank portion 31 of the tool holder TH2 is mounted in a spindle taper hole as shown in FIG. The detailed configuration is
The portions other than the tapered shank portion 31 are the same as those of the tool holder TH1 of the two-sided constraint type, and are denoted by the same reference numerals and description thereof is omitted.

In the case of using the tool holder TH2, the same operation and effect can be obtained as in the case of using the tool holder TH1 of the two-sided constraint type.

Further, in each of the tool holders TH1 and TH2, as shown in FIG. 8, a configuration may be adopted in which the periphery of the coolant supply connection port 8 provided in the front end face 1A of the spindle is formed as a concave face 1B.

In the above configuration, even if the ultrahigh-pressure coolant liquid C leaks from the contact surface, the leak is only in a narrow area with the concave surface 1B, and the pressing force F is limited to only the concave surface. For this reason, the spindle tip surface 1A and the flange end surfaces 10A of the tool holders TH1 and TH2 facing the spindle tip surface 1A.
The super-high-pressure coolant liquid C does not leak over the entire peripheral surface of the above, and the pressing force F does not spread. Therefore, the mounting accuracy of the tool holder with respect to the spindle 1 is maintained with high accuracy, and the processing accuracy is also maintained with high accuracy.

Further, the ultra-high pressure coolant liquid (12 to 1)
Even if high-pressure air (5 to 15 Mpa) or high-pressure inert gas (5 to 15 Mpa) is used instead of 4Mpa) C, it can be easily inferred that the same action and effect will be exhibited. Therefore, in the above embodiment of the present invention, the ultra-high pressure coolant liquid
Although (12-14 Mpa) C has been described, the use of a gas other than a liquid does not depart from the technical scope of the present invention. This is because a cooling action, a lubrication action, and a chip discharge action can be similarly expected for a blade or a work regardless of a liquid or a gas.

[0043]

According to the first aspect of the present invention, the small hole tool is rotated at a high speed, and the small hole is advanced while the high pressure coolant of about 12 to 14 Mpa is sprayed from the center through. The supply is reliably transmitted from the center through to the deep part, and reliable and efficient cutting can be performed without causing a shortage of coolant and heat generation due to the shortage. Furthermore, the chips created from the cutting edge of the tool for fine holes are:
High-pressure coolant liquid of about 12 to 14 Mpa in an extremely narrow hole can reliably and efficiently discharge outside the small hole.

According to the tool holder of the second aspect, the coolant supply connection port on the front end face of the spindle and the reception connection port provided on the flange end face of the tool holder are connected in a form of side through (flange through). Ultra high pressure coolant liquid
(12 to 14 Mpa) passes through the supply passage connected to the receiving connection port in the tool holder to reach the center through of the small hole tool, and the fitting surface between the main shaft hole and the fitting projection of the tool holder.
No liquid leakage occurs at the (connection part). For this reason,
The fitting protrusion of the tool holder to the spindle hole is completely installed,
It can maintain the machining accuracy of tool holder troubles and small hole machining with high accuracy, and is good at machining small holes themselves.

Further, since the above-mentioned tool holder is provided with a concave surface for side through (flange through) and this receiving connection port on the end face of a flange having a normal shape, a normal machining center is provided in a tool magazine. As the same type of tool holder, a tool holder for mounting a small hole tool can be mixed and installed. Thus, the small hole processing and the normal cutting processing can be performed in a mixed manner by changing the tool, so that the fine hole processing can be performed by a normal machining center without using a dedicated machine tool such as a small hole gun drill machine.

According to the third aspect of the present invention, the coolant supply connection port provided on the front end face of the spindle and the reception connection port opened in the contact surface of the facing flange end face of the tool holder are joined as a concave surface. Even if the ultra-high pressure coolant liquid leaks from the contact surface, the leak will only occur in a narrow area with the concave surface, and the pressing force can be limited to only the concave surface. Therefore, the super-high pressure coolant does not leak over the entire peripheral surface of the front end surface of the spindle and the flange end surface of the tool holder facing it, so that the pressing force does not spread, and the mounting accuracy of the tool holder with respect to the main shaft is high. Can be maintained.

According to the fourth aspect, a tool holder with a side through (flange through) of the same standard as that of a normal tool holder is provided in a tool magazine of an automatic tool changer in a mixed manner or alone, and the side through (flange through) is provided. When the attached tool holder is mounted on the spindle, the coolant supply connection port provided on the tip end face of the spindle and the reception connection port provided on the flange end face of the tool holder are connected.
Mpa) is transmitted to the cutting edge without liquid leakage, and fine hole drilling can be performed with a normal machining center while maintaining high precision. Therefore, work machining with a normal tool and gun drilling with an ultra-high pressure coolant using a tool holder with a side through (flange through) can be efficiently performed with a single machining center.

According to a fifth aspect of the present invention, the coolant supply connection port provided on the front end face of the main spindle is formed as a concave surface, and the receiving connection is formed on the contact face of the flange end face of the tool holder with the side through (flange through) facing the coolant connection port. Because the periphery of the mouth is joined as a plane, even if the ultra-high pressure coolant liquid leaks from this confronting surface, the leakage will be only in a narrow area with the concave surface,
Further, the pressing force is also limited only within this concave surface. For this reason,
The super-high-pressure coolant does not leak over the entire peripheral surface of the spindle front end surface and the flange end surface of the tool holder facing the main shaft, and the pressing force does not spread. Therefore, the mounting accuracy of the tool holder with respect to the spindle is maintained with high accuracy, and the processing accuracy is also maintained with high accuracy.

[Brief description of the drawings]

FIG. 1 is a right side view of a machine tool that carries out a method for processing a small hole according to the present invention.

FIG. 2 is a sectional view of a spindle and a tool holder of the present invention.

FIG. 3 is a cross-sectional view of a connection operation between a main shaft and a tool holder.

FIG. 4 is a perspective view of a connecting portion between a main shaft and a tool holder.

FIG. 5 is a sectional view of a two-sided restraint tool holder.

FIG. 6 is a sectional view of a tapered shank tool holder.

FIG. 7 is a sectional view showing the operation of fine hole processing and chip removal.

FIG. 8 is a perspective view in which a concave surface is provided on the front end surface of the spindle.

[Explanation of symbols]

 C Ultra-high pressure coolant liquid F Propulsion M Machining center HP Ultra-high pressure coolant generator H Gripping part H1 Small hole h Pilot hole S Center through TH1, TH2 Tool holder T1 Small hole tool P Piping PD Pilot drill V1, V2 Check valve 1 Main shaft 1A Main shaft tip surface 1B Concave surface 1C Hole 2 Center hole 3 Drawing bolt 3A Center hole 4 Recovery tube 5 Mist suction device 6 Supply line 8 Coolant supply connection port 8a Inner hole 10 Flange 10A Flange end surface 10B Confronting surface (concave surface) 10C V-groove ring 11 Receiving connection port 13 Supply passage 15 Coolant supply passage 20 Side through (flange through)

Claims (5)

[Claims] 1. A detachable tool holder having a small-diameter small-hole tool attached thereto is mounted on the tip of a spindle, and a high-pressure coolant liquid of about 12 to 14 Mpa is supplied from a center through hole of the small-hole tool into a work processing hole. A small hole processing method, characterized in that the fine hole is processed by spraying. 2. A tool holder for use in a method for machining a small hole, in which a high-pressure coolant of about 12 to 14 Mpa is sprayed from a center through hole drilled in the small hole tool.
A contact surface that faces the coolant supply connection port provided on the spindle front end surface is provided on the flange end surface of the tool holder, and a side through (flange through) that is a receiving connection port opened in this contact surface
A tool holder for use in a method for machining a small hole, characterized in that the supply passage is connected to a coolant supply passage leading to a center through of the small hole tool. 3. The coolant supply connection port provided on the front end face of the spindle is joined to the coolant supply connection port provided on the contact surface of the facing flange end surface of the tool holder with a concave surface around the reception connection port. Tool holder used for the described method for drilling fine holes. 4. A tool holder with a side through (flange through) of the same standard as a normal tool holder is provided in a tool magazine of an automatic tool changer in a mixed or independent manner, and the tool holder with a side through (flange through) is provided. A machining center wherein a coolant supply connection port provided on a front end face of a spindle and a supply connection port provided on a flange end face of a tool holder with a side through (flange through) are connected when mounted on a main spindle. 5. A coolant supply connection port provided on a tip end surface of a spindle is formed as a concave surface, and a periphery of a supply connection port formed in a contact surface of a flange end surface of a tool holder with a side through (flange through) opposed thereto is formed. The machining center according to claim 4, wherein the machining center is joined as a flat surface.