JP2000326119A - Liquid-tight collet - Google Patents

Abstract

(57) [Problem] To provide a square hole for inserting a square shaft portion of a shank in a liquid-tight collet. SOLUTION: Slots 23, 24 having a length not reaching the end surface 33b and the end surface 33a, respectively, are formed in the liquid-tight collet from the end surface 33a and the end surface 33b in the axial direction in parallel with each other. An annular fitting groove 36 is formed in a round hole 35 at the center of the collet into which the shank 26 having the square shaft portion 37 is inserted,
A piece 34 having a square hole 37 into which the square shaft portion 37 is inserted is fitted and fixed in the fitting groove 36.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid-tight collet for holding a shank such as a tap having a square shaft portion for preventing rotation and a hole for supplying a coolant (coolant).

[0002]

2. Description of the Related Art As shown in FIG. 13, Japanese Utility Model Registration No. 2502465 has a length not extending from an end face 1a and an end face 1b to an end face 1b and an end face 1a in parallel in the axial direction, respectively. A liquid-tight collet 1 having slits 2 and 3 is disclosed.

When machining is performed by holding a drill 6 having a coolant supply hole 5 with a collet holder 4 having the liquid-tight collet 1, the coolant a is supplied to the collet holder 4.
When the coolant a is fed from the inside, the coolant a is ejected from the cutting edge through the coolant supply hole 5 of the drill 6 toward the work (not shown) to cool the cutting portion and remove chips. At this time, the coolant a also contacts the rear end of the collet 1 and penetrates into some of the slits 3, but each of the slits 2 and 3 has a length that does not reach the end face 1b or the tip face 1a. And the collet 1 is in close contact with the shank 7 of the drill 6 and the collet 1 and between the shank 7 and the collet holder 4.
Coolant supply hole 6 for drill 6 without leaking out
To be ejected from the cutting edge of the drill 6.

[0004]

When machining with a tool such as a tap, a large torque is applied to the tool, so that the shank is provided with a square shaft portion for preventing rotation. If holes are to be formed in the liquid-tight collet, the liquid-tightness will be impaired. The reason is as follows.

[0005] When manufacturing a conventional collet for gripping a shank consisting only of a round shaft or a collet for gripping a shank having no coolant supply hole, the cylindrical boss portion is formed by NC.
The front taper portion and the rear taper portion are cut out by gripping with a machine tool such as a lathe, a slot is formed, and after other grinding and the like are performed, the boss portion of the material is finally cut off. When manufacturing the liquid tight collet 8 for taps as shown in FIGS. 14 and 15 by using this manufacturing method, the boss portion 18 of the material is gripped by a machine tool, and the front taper portion 9 and the rear taper portion are gripped. 10 and slitting grooves 11 and 1
After the formation of No. 2, it is necessary to further form a square hole 14 in a part of the center circular hole 13. When a cylindrical material is used, a through hole such as broaching or wire cutting is generally employed. Therefore, a square hole is formed by passing a broach, a wire, or the like through a round hole 13 formed in the material.
However, despite the fact that the round shaft portion 15 and the diagonal portion 16a of the square shaft portion 16 have the same diameter curved surface in the tap shank as shown in FIG. 16, the square shaft as shown in FIG. When the square hole 14 corresponding to the portion 16 is formed in the collet 8 by wire cutting or the like, it is difficult to make the four corners of the square hole 14 coincide with the curved surface of the diagonal portion 16a of the square shaft portion 16 and to drill. Therefore, the diagonal portion 14a at the corner of the square hole 14 is cut closer to a right angle than the diagonal portion 16a of the square shaft portion 16 in order to ensure the insertion of the shank. For this reason,
As shown in FIG. 17, when the shank is inserted into the collet 8, the diagonal portion 16a of the square shaft portion 16 of the shank and the collet 8
A groove 17 is generated between the square hole 14 and the diagonal portion 14a.

Since the grooves 17 extend through the collet 8 in the front-rear direction, the coolant leaks outside through the grooves 17 in the collet 8 without going to the coolant supply hole of the tool.

The formation of the grooves 17 can be avoided by forming the square holes 14 by a processing method other than the wire cutting processing or the like. In this case, however, the processing must be performed without the boss portions 18 provided. The production efficiency of the collet is reduced. That is, when the square hole 14 is formed at the entrance of the material of the collet 8 as shown in FIG. 18, the side of the square hole 14 is smaller than the diameter of the round hole 13, so that the inner surface of the round hole 13 is cut or ground. Becomes difficult. For this reason, machining is performed without attaching the boss 18 to be gripped by the machine tool, and the operator must supply the material to the machine one by one.

Accordingly, an object of the present invention is to provide a liquid-tight collet having a square hole.

[0009]

In order to achieve the above object, the invention according to claim 1 is directed to an end face (33b) which is parallel to an axial direction from a tip face (33a) and a tip face (33b).
Slot (2) that does not reach the tip surface (33a).
In the liquid-tight collet formed with (3, 24), an annular fitting groove (36) is formed in a round hole (35) at the center of the collet into which the shank (26) having the square shaft portion (26a) is inserted. And the square shaft portion (26a) is fitted in the fitting groove (36).
A liquid-tight collet in which a piece (34) having a square hole (37) into which is inserted is fitted and fixed is employed.

Further, the invention according to claim 2 is characterized in that the piece (3)
The liquid-tight collet according to claim 1, wherein a detent piece (38) is formed in 4), and the detent piece (38) is inserted into the slot (24).

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, this collet holder 2
Reference numeral 0 denotes a collet 19, a substantially cylindrical collet holder main body 20a into which the collet 19 is inserted, a retainer 21 for pressing the tip of the collet 19, and a nut 22 for connecting the retainer 21 to the collet holder main body 20a.

The collet 19 is a spring collet in which a plurality of slits 23 and 24 are formed along its axial direction. The collet 19 has a round shape of a shank 26 in a tool 25 such as a tap by expansion and contraction of a diameter accompanied by elastic deformation. Release or grab the shaft. In addition, a front taper portion 27 and a rear taper portion 28 reverse to the taper portion are formed on the outer peripheral surface of the collet 19.
Are formed.

The collet holder main body 20a is formed in a substantially cylindrical shape, and a conical surface 29 with which the rear tapered portion 28 of the collet 19 contacts is formed on the inner peripheral surface at the tip. The retainer 21 is formed in an annular shape, and a conical surface 30 with which the front tapered portion 27 of the collet 19 contacts is formed on the inner periphery. The nut 22 is screwed into a male screw formed on the outer peripheral surface of the distal end portion of the collet holder main body 20a.
Is engaged with the outer peripheral surface through a steel ball 31. As a result, the collet 19 is held between the collet holder main body 20a and the retainer 21, and when the shank 26 of the tool 25 such as a tap is inserted into the center of the collet 19 and the nut 22 is rotated in one direction, the front and rear tapers are formed. The sliding contact between the portions 27 and 28 and the front and rear conical surfaces 30 and 29 causes the collet 19 to reduce the diameter and grip the shank 26. When the nut 22 is turned in the other direction, a gap is formed between the front and rear tapered portions 27 and 28 and the front and rear conical surfaces 30 and 29, and the collet 19 expands in diameter to release the shank 26.

As shown in FIG. 1, this collet holder 20 can be processed while holding a tool 25 having a coolant supply hole 32 and ejecting a coolant a from the tip of the tool 25. Therefore, the collet 19 employs a structure for obtaining liquid tightness as described below.

That is, as shown in FIGS. 1, 2, and 7 to 9, the collet main body 33 is axially parallel to the distal end face 33b and the distal end face 33b of the collet main body 33, respectively. It has slits 23 and 24 extending so as not to reach the surface 33a. These two types of slits 23 and 24 are formed alternately at equal pitches in a cylindrical collet body 33.

One type of slit 23 extends axially from the front end face 33a of the collet body 33 and the end face 3
3b and the collet 19
Without reaching the fitting groove 36 and the step 39. Also, the rear end of the slit 23 is collet 1
The tapered portion 28 that closes at the outer periphery of 9 closely contacts the conical surface 29 of the collet holder body 20a, and the inner wall surface of the round hole 35 that closes the rear end of the slot 23 at the inner periphery of the collet closely contacts the shank 26. As a result, the coolant a coming from the rear of the collet main body 33 is
The flow into the inside is cut off. The other type of slot 24 extends in the axial direction from the end face 33b of the collet main body 33 and is closed without reaching the tip face 33a. The inner wall surface of the round hole 35 that closes the front end of the slit groove 24 on the inner periphery of the collet is formed by the shank 26.
Adhere to As a result, the coolant a coming from the rear of the collet main body 33 does not
As shown in FIG.

The collet 19 has a square shaft portion 26a of a tool 25 for generating a large torque such as a tap.
So that it can be maintained without impairing liquid tightness,
As shown in FIGS. 2 to 6, the collet main body 33 has a piece 34, and the tool 25 has an annular fitting groove 36 for fitting the piece 34 into a round hole 35 into which the shank 26 is inserted. ing.

The piece 34 is a means for receiving a large torque applied to the tool 25 at the time of machining by the tool 25 such as a tap. As shown in FIGS. And a square hole 3 formed at the center of the piece main body 34a.
7 and a detent piece 38 that protrudes radially from around the piece body 34a.

The piece main body 34a has a size such that after it is fitted in the fitting groove 36, it remains at a fixed position without deforming the collet body 33. The piece body 34a is the collet body 33
From behind, and is fitted into the fitting groove 36 by utilizing elastic deformation due to the existence of the slits 23 and 24 of the collet body 33.

The square hole 37 is formed in a shape and a size that allow a square shaft portion 26a formed at the rear end of the shank 26 of the tool 25 to be inserted as shown in FIG. The square holes 37 can be formed by broaching, wire cutting, or the like. When the piece body 34a fits into the fitting groove 36,
As shown in FIG. 4, a step 39 between the fitting groove 36 and the round hole 35 comes into contact with the end face 40 of the frame body 34a, and this step 39 blocks the diagonal portion 37a of the square hole 37 as shown in FIGS. I do. Therefore, the coolant a stays in the square hole 37 and does not flow toward the round hole 35.

The detent pieces 38 are provided corresponding to the slits 24 opening on the end face 33b of the collet main body 33 so as not to hinder the operation of inserting the pieces 34 into the collet main body 33 as described above. ing. The detent piece 38 is formed, for example, in a fin shape.

Preferably, as shown in FIG. 8, the location of the slit 24 in which the detent piece 38 fits is formed wider than the other locations. Further, a slope is formed at the front end of the detent piece 38 to facilitate insertion into the slot 24. The detent piece 38 may be omitted if the piece 34 can be detented and held in the collet body 33 even during processing.

Next, a method of manufacturing the collet will be described.

As shown in FIG. 8, a boss 4 is formed on a cylindrical material.
1 is formed, and the boss 41 is gripped by a machine tool such as an NC lathe. A front taper portion 27 and a rear taper portion 28 on the outer periphery of the collet main body 33 are cut out from the material by a machine tool, and a round hole 35, a fitting groove 36 and the like on the inner periphery of the collet main body 33 are cut out. Next, after forming the slits 23 and 24 and performing other processing such as surface grinding, the boss 41 is finally cut off. Thereby, the manufacture of the collet main body 33 is completed. On the other hand, the piece 34 is manufactured by predetermined processing means such as broaching, wire cutting and the like.

Thereafter, the piece 34 is inserted into the collet body 33 from the rear end side. The outer shape of the piece body 34a of the piece 34 is slightly larger than the inner diameter of the hole at the rear end of the collet body 33,
Since the collet body 33 can be elastically deformed by the presence of the slits 23 and 24, the piece 34 is
3 spreads and enters the fitting groove 36 in the collet main body 33. The collet main body 33 returns to the original shape at the same time when the piece 34 reaches the fitting groove 36, and holds the piece 34 so as not to come off. Further, when the piece 34 is inserted into the collet main body 33, the detent piece 38 is simultaneously fitted into the slot 24, so that the piece 34 is relatively non-rotatably held in the collet main body 33.

Next, the operation of the collet holder 20 and the operation of the collet 19 will be described.

As shown in FIG. 1, when the shank 26 of the tool 25 such as a tap is inserted into the collet holder 20 holding the collet 19, the square shaft portion 26a enters the square hole 37 of the bridge 34. Next, when the retainer 21 is moved toward the collet holder main body 22a by turning the nut 22, the rear tapered surface 28 and the front tapered surface 2 of the collet 19 are moved.
7 and the conical surfaces 29 and 30 of the collet holder main body 22a and the retainer 21 are in sliding contact with each other, whereby the collet 19 is elastically deformed in the diameter-reducing direction, and the shank 26 is tightened on the surface of the round hole 35. Accordingly, when the collet holder 20 is rotated to perform a threading process or the like with the tool 25, even if a large torque acts on the collet 19, the shank 26 is prevented from rotating to the collet 19 via the square shaft portion 26a and the piece 34. Since it is held, the shank 26 does not idle on the collet 19, and proper processing is achieved.

During processing of a work (not shown) by the tool 25, the coolant a is fed into the collet holder 20 by pressure. The coolant a flows from the empty space of the collet holder 20 to the rear end face 33 b of the collet 19. But,
The slit 23 extends from the front end face 33a of the collet body 33 along the axial direction and is closed without reaching the end face 33b, and is closed without reaching the fitting groove 36 and the step 39 of the collet 19. I have. The rear tapered portion 28 that closes the rear end of the slit 23 on the outer periphery of the collet 19 forms the conical surface 2 of the collet holder body 20a.
9, and the inner wall surface of the round hole 35 that closes the rear end of the slot 23 on the inner periphery of the collet comes into close contact with the shank 26. The other slit 24 extends in the axial direction from the end face 33b of the collet body 33 and is closed without reaching the tip face 33a. A round hole 35 for closing the front end of the slit groove 24 on the inner periphery of the collet.
The inner wall surface of the contact is in close contact with the shank 26. Thereby, the coolant a coming from the rear of the collet main body 33 is the collet 1
9 is blocked from flowing toward the front end face 33a, and does not leak out of the collet holder 20 from the slits 23 and 24.

The diagonal portion 37a of the square hole 37 is also blocked by the step 39 between the round hole 35 of the collet main body 33 and the fitting groove 36 as shown in FIGS. The coolant a does not leak out of the collet holder 20 from the portion 37a.

Accordingly, the coolant a which has been pressure-fed into the collet holder 20 is concentrated on the rear end of the shank 26 of the tool 25 such as a tap, and passes through the coolant supply hole 32 toward the work (not shown) from the tip of the tool 25. Gushing. Thereby, cooling of a cutting part, removal of cuttings, etc. are performed appropriately.

[0032]

According to the present invention, there is provided a liquid-tight collet provided with a slot having a length that does not reach the distal end face and the distal end face in parallel with the axial direction from the distal end face and the distal end face, respectively. An annular fitting groove was formed in the round hole at the center of the collet into which the shank having the shaft portion was inserted, and a piece having a square hole into which the square shaft portion was inserted was fitted and fixed in the fitting groove. From
Conduction outside the collet at the diagonal portion of the square hole can be blocked. Further, the piece can be fixed in the collet by utilizing the elastic deformation by the slit of the collet. Therefore, it is possible to reliably prevent the coolant from leaking from the collet.

Further, since the piece having the square hole is separate from the collet, the collet can be easily processed in a state in which a boss portion for processing is provided on the material, and the inner and outer diameters are simultaneously processed. By doing so, it is possible to finish with high accuracy.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a collet holder provided with a collet according to the present invention.

FIG. 2 is a front view of the collet shown in FIG.

FIG. 3 is a rear view of the collet shown in FIG. 1;

FIG. 4 is a sectional view taken along line IV-IV in FIG. 2;

FIG. 5 is a partially cutaway view showing a slot of a collet;

FIG. 6 is a sectional view taken along line VI-VI in FIG. 4;

FIG. 7 is a rear view of the collet main body.

8 is a sectional view taken along line VIII-VIII in FIG.

FIG. 9 is a partially cutaway view showing a slot of the collet body.

FIG. 10 is a front view of a piece.

FIG. 11 is a side view of a piece.

FIG. 12 is a sectional view taken along line XII-XII in FIG.

FIG. 13 is a longitudinal sectional view of a collet holder provided with a conventional collet for a drill.

FIG. 14 is a rear view of a conventional tapping collet.

15 is a sectional view taken along line XV-XV in FIG.

16A and 16B show a shank of a tap. FIG. 16A is a rear view of the shank, and FIG.

17 is a cross-sectional view showing a state where a tap shank is inserted into the collet of FIG.

FIG. 18 is a longitudinal sectional view showing another conventional collet.

[Explanation of symbols]

 23, 24 ... slot 26 ... shank 26a ... square shaft part 33a ... tip surface 33b ... terminal surface 34 ... piece 35 ... round hole 36 ... fitting groove 37 ... square hole 38 ... detent piece

Continued on the front page (72) Inventor Kiyofumi Akabane 10070, Sakajo, Sakajo-cho, Hanishina-gun, Nagano F-term in Alpstool Co., Ltd. 3C032 JJ09

Claims (2)

[Claims] 1. A shank having a square shaft portion is provided in a liquid-tight collet provided with a slot having a length that does not reach the end surface and the end surface, respectively, in the axial direction from the end surface and the end surface. An annular fitting groove is formed in a round hole at the center of the collet to be inserted, and a piece having a square hole into which the square shaft portion is inserted is fitted and fixed in the fitting groove. Liquid tight collet. 2. The liquid-tight collet according to claim 1, wherein a detent piece is formed on the piece, and the detent piece is inserted into the slot.