JP3801862B2 - Tool holder with fluid passage - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides a fluid passage that can reliably supply an appropriate amount of coolant, cutting oil, or other cutting fluid supplied from the machine tool side to a cutting tool when cutting with a cutting tool such as a reamer or end mill. The present invention relates to a tool holder provided.
[0002]
[Prior art]
Conventionally, when cutting a material such as a metal with a blade, a large amount of coolant such as coolant or cutting oil is supplied to the processing portion to improve the cutting workability.
By the way, the cutting tool is chucked via a collet on a tool holder mounted on a spindle of a machine tool, and a cutting fluid supplied from the machine tool side is supplied with a supply hole of the tool holder and a slit portion of the collet, or a cutting tool. It is supplied through an oil supply hole formed in a central portion penetrating in the axial direction of the tool.
Many tool holders having fluid passages for supplying the cutting fluid have been developed and are in use. For example, there are conventional tool holders shown in FIGS.
[0003]
This prior art was previously proposed by the present applicant in Japanese Patent No. 3035167, and in the figure, 1 is provided with a shank portion 2 for insertion to be attached to the spindle of the machine tool at one end, The other end is a tool holder provided with a tool holding means 5 such as a tool holding collet 4 fitted to the chuck cylinder 3.
The tool holding means 5 is configured to grip the shank portion Ts of the cutting tool T via a cylindrical collet 4.
The collet 4 is formed in a cylindrical shape having an insertion hole 6 for inserting the shank portion Ts of the cutting tool T at the center, has a flange portion 7 at the tip portion, and is arranged at the outer peripheral portion near the tip. A plurality of axial slits 8 reaching the insertion hole 6 are formed.
A cavity 9 is formed inwardly on the rear end side of the collet 4, and a tail plug body 12 having a central hole 11 is screwed into the rear end opening 10. A ring 13 that contacts the inner wall surface of the tool holder 1 is provided on the outer peripheral surface of the body 12 so that the cutting fluid does not leak through the outer peripheral surface of the collet 4.
[0004]
The tool holding means 5 is a fastener that is rotatably disposed via an outer fitting chuck cylinder portion 3 into which the collet 4 is fitted, and a bearing 16 attached to a retainer 15 around the outer fitting chuck cylinder portion 3. The collet 4 holding the cutting tool T via the external fitting chuck cylinder portion 3 is caused to perform a diameter reduction or diameter expansion operation by rotating the fastening tool 17 forward or backward. It is like that.
[0005]
The collet 4 is formed with a plurality of fluid passages 18 along the axial direction in each of the outer peripheral portions of the insertion hole 6 and between the adjacent slit portions 8. Each fluid passage 18 includes the central hole 11 of the cavity portion 9 and the tail plug body 12 so as to penetrate the collet 4 in the axial direction, and a fluid supply passage 19 that is a central hole of the tool holder 1. It is possible to communicate with.
[0006]
Further, the slit portion 8 has a rubber that traverses the slit portion 8 so as to abut against the inner wall surface 3a of the outer fitting chuck cylinder portion 3 and the outer peripheral surface of the shank portion Ts of the cutting tool T. , A rod-shaped oil stopper 20 formed of an elastic body such as soft resin is provided to prevent the cutting fluid from flowing out from the hollow portion 9 through the slit portion 8 to the end portion on the cutting tool T insertion side. Like to do.
[0007]
The oil stopper 20 prevents the cutting fluid supplied from the fluid supply passage 19 from flowing out into the tip of the collet 4 through the slit portion 8, and the cutting fluid is surely ejected from the fluid passage 18. I'm trying to regulate it.
Reference numeral 21 denotes a spherical jetting tool which can change the jetting angle of the cutting fluid attached to the tip opening of the fluid passage 18 formed in the axial direction of the tip of the collet 4, and has a penetrating jet hole 22 formed therein. ing. Therefore, the ejection angle of the cutting fluid can be appropriately adjusted for each cutting tool T to be used according to the protruding length from the insertion hole 6, the diameter, the shape of the tip blade, the rotational speed, and the like. ing.
[0008]
[Problems to be solved by the invention]
According to the conventional tool holder having the fluid passage configured as described above, the production of the fluid passage 18 of the collet 4 which is the passage of the cutting fluid supplied from the machine tool side becomes extremely complicated, and the production cost of the collet is reduced. Is high. An oil stopper made of an elastic body attached to prevent the cutting fluid from flowing out from the hollow portion 9 through the slit portion 8 to the end including the flange portion 7 on the cutting tool T insertion side. No. 20 has changed over time due to long-term use and cannot reliably prevent the outflow of the cutting fluid. For each cutting tool T to be used, the protruding length from the insertion hole 6, the diameter, the shape of the tip blade, There is a problem in that it becomes impossible to reliably supply the cutting fluid by appropriately adjusting according to the rotational speed or the like.
[0009]
The present invention solves the above-described problems, simplifies the configuration of the cutting fluid supply passage of the straight collet that is inserted into the holder body of the tool holder, and facilitates assembly, so that the cutting fluid flows out from the outer periphery of the straight collet. It is an object of the present invention to provide a tool holder having a fluid passage that can prevent the above-mentioned problem relatively easily and can reliably supply the cutting fluid to the cutting tool.
[0010]
[Means for Solving the Problems]
The invention of claim 1 has a shank portion inserted into a spindle of a machine tool at one end, extends to the other end portion in line with the axis of the shank portion, and has a diameter toward the distal end on the outer peripheral surface. A holder main body having a chuck cylinder formed with a tapered surface, a clamping cylinder for tightening the chuck cylinder from the outer peripheral surface side, and a collet for gripping a tool fitted in the chuck cylinder, In a tool holder that allows the tool to be detachable by reducing or restoring the diameter of the chuck cylinder by a clamping cylinder, a straight collet that is fitted and held in the chuck cylinder and / or a fluid supply path of the holder body to the tool. A fluid passage communicating therewith, and having a slit portion formed on the cylindrical wall surface of the straight collet that is separated by a predetermined distance in the circumferential direction extending in the axial direction; The end portion is provided with a flange portion formed with a locking portion made of a screw on the outer peripheral surface, and the locking portion of the flange portion has a central through hole through which the shank portion of the tool passes in the center, and A collet cap having a horizontal end surface formed by polishing is detachably provided on the inner wall surface of the outer peripheral protruding portion, and an end face of the outer peripheral protruding portion is attached to the end surface of the chuck cylinder in use. The collet cap has an outer peripheral protruding portion horizontal end face which can be in close contact with each other.
[0011]
According to a second aspect of the present invention, in the tool holder having the fluid passage according to the first aspect, the collet cap has a central through hole through which a shank portion of the tool penetrates in the center and a fluid that ejects fluid to the tip end side of the tool. It has a jet hole.
[0012]
A third aspect of the present invention is the tool holder having the fluid passage according to the first aspect, wherein the collet cap has a tightening auxiliary portion such as a blind hole or a notch for a tightening tool such as a wrench. And
[0014]
According to a fourth aspect of the present invention, there is provided a tool holder including the fluid passage according to any one of the first to third aspects, wherein the chuck portion has a horizontal surface between a tip end horizontal surface and the collet cap outer peripheral protruding portion horizontal end surface. It is characterized in that they are brought into close contact with each other via a spacer made of a ring-shaped plate material having elasticity or an O-ring sealing material.
[0015]
According to a fifth aspect of the present invention, in the tool holder including the fluid passage according to any one of the first, third, and fourth aspects, the fluid passage communicating with the fluid supply passage of the holder body is provided. When provided in the tool, a seal member that contacts the outer peripheral surface of the shank portion of the tool is provided on the inner peripheral surface of the central through hole of the collet cap.
[0016]
According to a sixth aspect of the present invention, in the tool holder having the fluid passage according to the first aspect, when the collet cap is mounted on the collet collar, a straight collet holding the tool is inserted into the chuck cylinder. After tightening the chuck cylinder, an engaging portion made of a female screw of the collet cap is attached to the engaging portion made of the male screw of the straight collet, and the tip end surface of the chuck tube and the collet cap are polished. The outer peripheral projecting portion horizontal end surface subjected to the above is closely attached to each other.
[0015]
According to the tool holder having the fluid passage of the present invention having the above-described configuration, the cutting tool supplied from the machine tool side is mounted by gripping the cutting tool through the fluid supply passage formed in the holder body. The collet cap is engaged with a locking portion made of a male screw formed in the straight collet collar, and the tip end surface of the chuck cylinder and the collet cap are polished. The machined outer peripheral projections and the horizontal end surfaces are in close contact with each other, and the cutting fluid is ejected from the desired position, so that the cutting fluid can be reliably supplied to the cutting tool and wasted from the slit portion of the straight collet. It can be prevented from being washed away, and the cutting work can be performed efficiently.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a tool holder having a fluid passage according to the present invention will be described with reference to FIGS.
FIG. 3 is a sectional view showing a use state of the embodiment according to the present invention.
In FIG. 3, reference numeral 30 denotes a holder body of a tool holder. The holder body 30 is formed at a tapered shank portion 31 to be inserted into a spindle of a machine tool (not shown) and an end portion on the large diameter side of the tapered shank portion 31. The gripping flange 32 extends from the end surface of the flange 32 on the side opposite to the taper shank portion in the direction opposite to the taper shank portion 31 so as to coincide with the axis of the taper shank portion 31 and extends from the flange 32 to the outer peripheral surface. A chuck cylinder 33 having a cylindrical diameter formed with a tapered surface 32a having a diameter that decreases toward the tip.
[0017]
Reference numeral 34 denotes a roller holding cylinder that is loosely fitted to the outer periphery of the chuck cylinder 33. The roller holding cylinder 34 is a cylindrical body whose diameter decreases toward the tip at a taper angle substantially similar to the tapered surface 33a of the chuck cylinder 33. Formed from. The roller holding cylinder 34 is held so as not to fall out of the chuck cylinder 33 by a retaining ring 35 provided on the outer periphery of the tip end portion of the chuck cylinder 33.
[0018]
The roller holding cylinder 34 is provided with a large number of needle rollers 36 fitted in the circumferential direction at a predetermined angle with respect to the axis of the roller holding cylinder 34 in the circumferential direction. Each needle roller 36 is formed to have a diameter larger than the wall thickness of the roller holding cylinder 34, so that each needle roller 36 protruding toward the inner peripheral surface side of the roller holding cylinder 34 is formed on the tapered surface 33 a of the chuck cylinder 33. Each needle roller 36 that is brought into contact with and protrudes toward the outer peripheral surface side of the roller holding cylinder 34 is configured to contact an inner peripheral surface of a tightening cylinder 37 that will be described later.
[0019]
The clamping cylinder 37 is for reducing the diameter of the chuck cylinder 33 and tightly gripping the target tool. The clamping cylinder 37 is fitted to the outer periphery of the chuck cylinder 33 via a needle row 36 held by a roller holding cylinder 34. Combined. The inner peripheral surface of the fastening cylinder 37 is configured as a tapered cylindrical surface whose diameter decreases from the end facing the flange 32 toward the tip. A retaining ring 38 that also serves as a seal is attached to the inner periphery of the base end portion of the fastening cylinder 37 on the flange 32 side, and this retaining ring 38 that also serves as a seal contacts the outer peripheral surface of the chuck cylinder 33. Thus, the sealing function is exhibited, and the end of the roller holding cylinder 34 is brought into contact with the end face of the roller holding cylinder 34 to prevent the fastening cylinder 37 from coming off from the chuck cylinder 33.
[0020]
Reference numeral 40 denotes a straight collet (hereinafter referred to as a collet) having a straight outer peripheral surface that is fitted to the chuck cylinder 33 of the holder main body 30 by gripping a cutting tool. The collet 40 has both end portions 40a and 40b in the axial direction. Slit portions 41 and 42 that also serve as cutting oil passages, which will be described later, cut alternately in the axial direction are formed, and a flange portion 43 is formed at the distal end portion of the cylindrical body. The outer peripheral surface is provided with a male screw 44 as a locking portion.
[0021]
Reference numeral 50 denotes a collet cap that is screwed onto the collar portion 43 of the collet 40. The cap 50 has a through-hole 51 through which the shank portion Ts of the cutting tool T passes at the center, and the through-hole. with the cutting fluid ejection hole 51a that cut into a substantially V-shape at a predetermined interval is formed than the diameter direction 51, screwed with the external thread 44 of the collar portion 43 on the inner peripheral wall surface of the outer peripheral protruding portion 52 An internal thread 53 that is an engaging portion to be formed is formed.
Further, the horizontal end face 54 of the outer peripheral protrusion 52 of the collet cap 50 is preferably polished by polishing or the like, and the inner peripheral surface height (width) of the outer peripheral protrusion is determined by the collet. It is formed larger than the height (wall thickness) of the collar portion 43. Reference numeral 55 denotes a blind hole as a tightening auxiliary portion for inserting a tightening tool such as a wrench.
A plurality of grooves 56 serving as cutting fluid supply passages having a predetermined depth are formed on the inner wall surface of the chuck cylinder 33 of the holder body 30, thereby being used as a supply passage for cutting fluid supplied from the machine tool side. Further, the elastic deformation of the chuck cylinder 33 in the diameter reducing direction by the clamping cylinder 37 is further facilitated.
[0023]
In the tool holder having the fluid passage according to the embodiment configured as described above, when the cutting tool T is gripped, the collet 40 is fitted to the shank portion Ts of the cutting tool T, and the collet 40 is cut together. The shank portion Ts of the tool T is inserted into the cylindrical hole of the chuck cylinder 33. In this state, when the clamping cylinder 37 is rotated in the clockwise direction, each needle roller 36 that contacts the tapered cylindrical surface of the clamping cylinder 37 rotates in a direction perpendicular to its own axis while rotating on the outer peripheral surface of the chuck cylinder 33. The roller holding cylinder 34 moves while rotating with the revolution of the needle roller 34 from the tip end side of the chuck cylinder 33 toward the flange 32, and at the same time, the clamping cylinder 37 also moves in the direction of the flange 32. Move to. As a result, the distance between the tapered cylindrical surface of the clamping cylinder 37 and the outer circumferential tapered surface of the chuck cylinder 33 is reduced, so that the clamping cylinder 33 moves the chuck cylinder 33 from the outer circumference to the inner circumference via the needle rollers 36. The pressure is reduced from the entire circumference to reduce the diameter. As a result, the shank portion Ts of the cutting tool T inserted into the cylindrical hole of the chuck cylinder 33 is clamped and held via the collet 40.
[0024]
Further, the cutting tool T is passed through the central through hole 51 of the collet cap 50 and formed on the inner peripheral wall surface of the outer peripheral protruding portion 52 of the cap 50, so that the screw 53 is screwed with the outer peripheral male screw 44 of the collet collar 43. The horizontal end face 54 of the outer peripheral protrusion 52 of the cap 50 is configured to be in close contact with the tip end face 33a of the chuck cylinder 33.
[0025]
Next, the cutting fluid supply state to the cutting tool in the tool holder provided with the fluid passage in the above-described embodiment will be described.
As shown in FIG. 3, the cutting fluid supplied from the machine tool side (not shown) is supplied to the grooves 56 that are a plurality of fluid supply paths formed on the inner wall surface of the chuck cylinder 33 through the central hole 30 a of the holder body 30. The cutting fluid in the groove 56 gathers at the tip of the collet 40 via the slit portion 41 of the collet 40 and the outer peripheral surface of the cutting tool T from the V-shaped ejection hole 51a formed in the central through hole 51 of the collet cap 50. Can be reliably supplied to the tip blade portion and the processing portion.
[0026]
Since the cutting fluid collected at the tip of the collet is tightened and mounted so that the horizontal end surface 54 of the outer peripheral projection 52 of the collet cap 50 and the tip surface 33a of the chuck cylinder 33 are in close contact with each other. The collet 40 is not directly ejected from the fluid passages of the slit portions 41 and 42 in the opposite direction away from the cutting tool T.
[0027]
When the tightening cylinder 37 in the tightened state is rotated in the counterclockwise direction opposite to the above-described operation, the roller holding cylinder 36 moves to the tip side of the chuck cylinder 33 and the tightening cylinder 37 also moves in the same direction. . For this reason, the chuck cylinder 33 that has been reduced in diameter is restored to its original diameter, and the gripping force on the tool T is released, so that the tool T can be removed or replaced.
[0028]
According to the present invention, the grooves 56 are formed on the inner wall surface of the chuck cylinder 33 at a predetermined interval, and the grooves 56 are used as fluid supply passages. The cap 50 is screwed into the tip flange 43 of the collet 40 for holding the cutting tool T to be cut, and the horizontal end face 54 of the cap outer peripheral protrusion 52 and the tip end face 33a of the chuck cylinder 33 are brought into close contact with each other, thereby leaking cutting fluid Therefore, the collet 40 can be easily and inexpensively manufactured without using the collet 40 having a complicated shape as in the prior art.
[0029]
FIG. 6 is a tool holder provided with a fluid passage showing a second embodiment of the present invention, in which a fluid passage communicating with a fluid supply passage of the holder body is provided in the cutting tool. . And the case where the cutting fluid is made to flow out from the blade edge | tip 61 of the cutting tool T through the fluid channel | path 60 which penetrates the axial direction of the cutting tool T2 is shown.
Thus, when the cutting tool T2 has the fluid passage 60, the shape of the collet cap 50 of the first embodiment described above, that is, the V-shaped cutting formed by cutting into the inner peripheral surface of the central through-hole 51. Instead of providing the liquid ejection hole 51a, a seal that abuts the outer peripheral surface 62 of the shank portion Ts of the cutting tool without providing the fluid ejection hole 51a on the inner peripheral surface of the central through hole 71 of the collet cap 70. the member 63 is provided, in which fluid is prevented from flowing out from the central opening 71 of the collet cap 70, outflow of the cutting fluid, penetrating in the axial direction of the cutting tool T2 which communicates with the fluid supply passage of said holder body It flows out from the ejection hole 60a opened to the cutting edge 61 portion of the cutting tool T2 only through the fluid passage 60.
In the configuration other than that described above, the same parts as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.
[0030]
In each of the above embodiments, the collet 40 has been described as being straight.
Further, the engaging part of the collet 40 collar part and the engaging part of the collet cap are engaged by screwing with a female screw or a male screw. However, the present invention is not limited to this, and the key uses an L-shaped groove. The horizontal end face 54 of the cap outer periphery protruding portion 52 and the tip end face 33a of the chuck cylinder 33 may be brought into close contact with each other by engagement or the like.
[0031]
Further, as in the modification shown in FIGS. 7 and 8, a spacer 80 or O made of a ring-shaped plate having elasticity between the horizontal end face 54 of the cap outer peripheral protrusion 52 and the tip end face 33a of the chuck cylinder 33 is used. Needless to say, the end surfaces may be brought into close contact with each other by interposing a seal portion 81 such as a ring.
Furthermore, in the first embodiment, the fluid ejection hole formed in the collet cap is shown on the inner peripheral surface of the central through hole through which the tool passes. However, the shank portion of the tool has a large diameter. In this case, a plurality of fluid ejection holes may be provided at positions away from the central through-hole, and further, a nozzle capable of controlling the ejection angle may be attached to the fluid ejection hole. is there.
[0032]
【The invention's effect】
As described above, according to the tool holder having the fluid passage of the present invention, the straight collet that fits and holds the cutting fluid supplied from the machine tool side through the fluid supply passage of the holder body to the chuck cylinder. And / or supplying a fluid passage of the tool, and providing a hook portion having a locking portion on an outer peripheral surface at a tip portion of the straight collet, and a locking portion formed of a male screw of the hook portion in the center. A collet cap having a central through-hole through which the shank portion of the tool passes and an engagement portion made of a female screw is formed on the inner wall surface of the outer peripheral protruding portion is detachably provided. Since the construction is such that the horizontal end surface of the outer peripheral protruding portion subjected to the polishing of the collet cap can be brought into close contact with each other, the following effects are obtained.
That is, if the cutting tool itself does not have a fluid supply hole, the tip of the straight collet passes through the slit portion of the straight collet fitted to the chuck cylinder through the central hole that is the fluid supply path of the holder body. Can be reliably supplied from the V-shaped ejection hole formed in the central through hole of the cap along the outer peripheral surface of the cutting tool to the tip edge portion and the processing portion of the cutting tool, and the cutting fluid can be fed into the straight collet slot. In the case where the cutting tool itself has a fluid supply hole, the fluid supply hole of the cutting tool can be prevented from passing through the central hole which is the fluid supply path of the holder body. Since the cutting fluid can be supplied only from the cutting edge of the cutting tool via the cutting tool, the cutting work can be efficiently performed with a small amount of the cutting fluid.
[0033]
Furthermore, it is possible to reliably prevent the cutting fluid during processing from entering the needle roller portion from the tip portion of the fastening cylinder and dust from entering the groove.
[0034]
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a conventional tool holder having a cutting oil supply mechanism.
FIG. 2 is a perspective view of a collet used in a tool holder having a conventional cutting oil supply mechanism.
FIG. 3 is a longitudinal sectional view of a tool holder showing a first embodiment of a tool holder provided with a fluid passage according to the present invention.
4 is a cross-sectional view taken along line AA in FIG.
FIGS. 5A and 5B are explanatory diagrams of a collet cap according to an embodiment of the present invention, in which FIG. 5A is a bottom view seen from the tip side of the cutting tool, FIG. 5B is a plan view of FIG. It is BB sectional drawing of (a).
FIG. 6 is a longitudinal sectional view of a tool holder showing a second embodiment of a tool holder provided with a fluid passage according to the present invention.
FIG. 7 is a longitudinal sectional view of an essential part showing a modified example of a mounting state of a collet cap in a tool holder provided with a fluid passage according to the present invention.
FIG. 8 is a longitudinal sectional view of an essential part showing a modified example of a mounting state of a collet cap in a tool holder provided with a fluid passage according to the present invention.
[Explanation of symbols]
30 Tool holder body 31 Shank part 32 Flange 33 Chuck cylinder 33a Tip end face 34 Roller holding cylinder 36 Needle roller 37 Tightening cylinder 40 Straight collet 41, 42 Slotted part 43 Fence part 44 Male thread (locking part)
50 Collet cap 51 Central through hole 51a Cutting fluid ejection hole 52 Peripheral protrusion 53 Female thread (engagement part)
54 Horizontal end face 56 Groove (fluid supply path)

Claims (6)

Has a shank part that is inserted into the spindle of a machine tool at one end, and extends at the other end to coincide with the axis of the shank part, forming a tapered surface with a smaller diameter toward the tip on the outer peripheral surface A holder main body having a chuck cylinder, a clamping cylinder for clamping the chuck cylinder from the outer peripheral surface side, and a collet for gripping a tool fitted in the chuck cylinder, and the chuck cylinder by the clamping cylinder. In a tool holder in which the tool can be detached by reducing or restoring the diameter,
A straight collet that is fitted and held in the chuck cylinder and / or a fluid passage that communicates with a fluid supply path of the holder main body is provided in the tool, and in a circumferential direction that extends in the axial direction on the cylindrical wall surface of the straight collet The straight collet has a slit portion formed at a predetermined interval, and a hook portion formed with a locking portion made of a screw on the outer peripheral surface is provided at the distal end portion of the straight collet. Collet having a central through hole through which the shank of the tool passes in the center, an engaging portion made of a female thread on the inner wall surface of the outer peripheral protruding portion, and a horizontal end surface by polishing on the end surface of the outer peripheral protruding portion A cap is detachably provided so that the tip end surface of the chuck cylinder and the horizontal end surface of the outer peripheral protruding portion of the collet cap can be brought into close contact with each other during use. Tool holder with the road.   2. The fluid passage according to claim 1, wherein the collet cap has a central through hole through which a shank portion of the tool passes in a center and a fluid ejection hole for ejecting fluid to the tip end side of the tool. Tool holder provided.   2. The tool holder having a fluid passage according to claim 1, wherein the collet cap has a tightening auxiliary portion such as a blind hole or a notch for a tightening tool such as a wrench.   The seal cylinder is made to adhere to each other via a spacer made of a ring-shaped plate material having elasticity or an O-ring or the like between the horizontal surface of the tip of the chuck tube and the outer peripheral protruding portion of the collet cap. A tool holder comprising the fluid passage according to any one of claims 1 to 3.   When a fluid passage communicating with the fluid supply passage of the holder body is provided in the tool, a seal member that abuts the outer peripheral surface of the shank portion of the tool is provided on the inner peripheral surface of the central through hole of the collet cap. A tool holder provided with the fluid passage according to any one of claims 1, 3, and 4. The collet cap is attached to the collet collar by inserting a straight collet holding the tool into the chuck tube, tightening the chuck tube, and then engaging the locking portion made of the straight collet screw. An engaging portion made of a female screw of the collet cap is attached, and the tip end surface of the chuck cylinder and the outer peripheral protruding portion horizontal end surface of the collet cap polished are in close contact with each other. A tool holder comprising the fluid passage according to claim 1.

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