JPH11207504A - Chuck for holding small-diameter tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To oil a center-through coolant without trouble by providing a center- through coolant oiling means, for feeding a coolant oil to the knife edge of a small-diameter tool from a pull-stud bolt mounted on the upper axis center of a holder body. SOLUTION: The presser tube bolt 25 of a thrust bearing 24 and a pull-stud bolt 26 are threadedly inserted into the screw hole 4c in the axis center part of a holder body 4. A first, second, and third passages 29, 30, and 31 penetrating the respective axis centers of respective pull-stud, seal-pushing, and pulling bolts 26, 27, and 17 are formed on these axis centers of these bolts respectively. A center-through coolant oiling means 32, for feeding a coolant oil to the knife edge of a small-diameter tool 3 from the bolt 26 like an arrow B, is formed by these passages 29-31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-diameter tool holding chuck for holding a small-diameter rotary tool used in a precision machine tool or the like, and more specifically, to supplying coolant oil to the cutting edge of the small-diameter tool. The present invention relates to a small-diameter tool holding chuck that can be used.

[0002]

2. Description of the Related Art With the advancement and development of electronics, these related devices have become smaller, lighter and more precise. Therefore, small-diameter tools are used in large quantities for machining, metal drilling, and the like for manufacturing these devices, and a high-precision chuck for holding the small-diameter tools is demanded.

[0003] As this kind of chuck for holding a small diameter tool,
The applicant of the present application has proposed a chuck described in Japanese Utility Model Publication No. 2-30166 and has been well received. That is, the chuck has a shank portion at an upper portion, a fitting hole coaxial with the shank portion at a lower end surface, and a lateral hole communicating with the fitting hole at a lower side surface. A main body, an adapter fixed coaxially to a lower end surface of the holder main body, inserted through the fitting hole and penetrating a tapered holding hole coaxial with the fitting hole; A tapered collet which is inserted removably and has a female screw portion coaxial with the holding hole at the upper end, and a small-diameter tool holding hole coaxial with the female screw portion at the lower end. The tapered collet is housed in a deeper part of the fitting hole above the upper end face, has a bevel gear on the upper surface side, and has a vertically extending bolt part detachably screwed to the female screw part on the lower surface side. A pull screw and the above-mentioned bevel gear, A thrust bearing that performs centering of the screw, and a pinion that is rotatably housed in the lateral hole and that meshes with the bevel gear at an inner end portion, and that a rotational operation is performed from an opening of the lateral hole. And an operating body having a tool engaging portion at an outer end portion for performing the operation.

[0004]

Recently, a machine tool is provided with a coolant (pressure 70 kgf) from a spindle center.
/ Cm ² ) is the mainstream, but the above-described chuck has not been provided with this measure. Therefore, it is conceivable to form a coolant oil supply hole having a diameter of 4 to 6 mm only in a pull bolt (draw bolt) for pushing and pulling the taper collet.

However, because the neck diameter of the pull stud bolt is small, a hole for inserting a wrench cannot be provided. Therefore, the operation is performed by removing the pull stud bolt and tightening the draw bolt to the wrench (ie, an end mill or the like). After clamping the small-diameter tool, the pull-stat bolt was attached, which required a lot of work. Further, the chuck described in the above-mentioned publication has a thrust bearing for centering a pull bolt (pull screw) having a bevel gear, but does not have a thrust bearing for a drive bevel pinion. There was a possibility that the occlusal accuracy (engagement accuracy) would be incorrect.

Furthermore, in the chuck described in the above-mentioned publication, a snap ring (snap ring) is employed for positioning the driving bevel pinion, and in this case, there is a possibility that the snap ring may fly out at the time of high-speed rotation. A first object of the present invention is to provide a small-diameter tool holding chuck with a center-through coolant oil supply function.

A second object of the present invention is to provide a driving bevel pinion thrust bearing while achieving the above first object, thereby ensuring the accuracy of occlusal engagement with a bevel gear and generating vibration even at high speed rotation. Is to cause no cause. A third object of the present invention is to achieve the first and second objects described above and to provide a positioning body by screw connection instead of a conventional retaining ring, thereby eliminating play of a pinion and a bevel gear, High-speed rotation was made possible.

[0008]

SUMMARY OF THE INVENTION The present invention provides a holder body 4 having a horizontal hole 4A which rotates integrally with a main shaft 1 of a machine tool.
An adapter 6 provided at a lower end of the holder body 4;
A taper collet 8 having a threaded portion 7 at an upper portion thereof inserted into the adapter 6, a drive bevel pinion 21 housed in the lateral hole 4A, and a bevel gear 20 meshing with the bevel pinion 21; 7, a pulling bolt 17 screwed to the shaft 7, and the driving bevel pinion 21 is rotated about this axis to rotate the pulling bolt 17 about this axis via a bevel gear 20, thereby forming a taper collet. In the small diameter tool holding chuck for mounting the small diameter tool 3 according to 8, the following technical measures are taken in order to achieve the first object described above.

That is, the present invention according to claim 1 includes a center through coolant supply means 32 for sending coolant oil from the pull stud bolt 26 mounted on the upper axis of the holder body 4 to the cutting edge of the small-diameter tool 3. It is characterized by having. By adopting such a configuration, the center through coolant can be supplied without any trouble.

The center through coolant supply means 3
2 is a first passage 29 penetrating the axis of the pull stud bolt 26 and a seal ring 30 on the upper end surface of the bevel gear 20.
At least a second passage 30 penetrating the axis of the pushing bolt 27 for pressing the shaft and a third passage 31 penetrating the axis of the pulling bolt 17 ( Claim 2) By adopting such a configuration, the coolant can be reliably supplied with a simple structure improvement.

Further, in the present invention, in order to achieve the above-mentioned second object, a clamp bolt 29 is provided on the holder main body 4 so as to face the drive bevel pinion 21, and a collar 28 fitted on the push-in bolt 27 is provided. The clamp bolt 29
Are brought into contact with each other to form a thrust bearing of the drive bevel pinion 21 (claim 3).

By adopting such a configuration, the occlusal accuracy of the pinion 21 and the bevel gear 20 is reliably ensured, and by employing the collar 28, coolant supply can be maintained. Further, in the present invention, in order to achieve the third object, a tool engaging portion 22 for rotating the pinion 21 around the axis is formed at the outer end of the driving bevel pinion 21. And
A positioning body 23 having an operation space 23A for the tool engaging portion 22 is screwed into the lateral hole 4A in a state of contacting the outer end surface of the pinion 21 (claim). 4).

By adopting such a configuration, external operation of the drive bevel pinion 21 can be performed without any trouble by inserting a tool through the operation space 23A.
The projection of the positioning body 23 was surely prevented even at high speed rotation.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a vertical sectional view of a state in which a small-diameter tool 3 exemplified by an end mill is mounted on a main shaft 1 of a machine tool via a chuck 2 according to the present invention, and FIG.
A-A arrows are shown.

The chuck 2 has a holder body 4 having a tapered shank portion 3 inserted into the main shaft 1, and an adapter 6 fitted to the lower end of the holder body 4 by spigot fitting and attached with a plurality of bolts 5. And a tapered collet 8 inserted into the adapter 6 and having a threaded portion 7 at the top. The holder body 4 has a flange 9 for holding an arm of an automatic tool changer at an intermediate portion, and a drive key groove 10 is formed in the flange 9, and the drive key groove provided on the spindle 1 is formed in the groove 10. 11 is engaged, and the rotational force of the main shaft 1 is transmitted to the holder main body 4 via the drive key 11 so that the holder main body 4 rotates integrally with the main shaft 1.

The adapter 6 has a tapered collet holding hole 12 concentric with the holder body 4 formed through the center of the adapter 6. The tapered portion 13 whose diameter is reduced from the lower end toward the middle is formed in the holding hole 12. Is formed, and the tapered collet 8 is removably inserted into the holding hole 12. The outer periphery of the tapered collet 8 is formed on a tapered surface 14 that fits (fits) with the tapered portion 13, and a straight tool holding hole 15 is formed through the axial center of the collet 8. A female screw is formed at the upper end (rear part) to form a screw portion 7, and a plurality of slits 16 are formed from the lower end of the collet 8 to the vicinity of the screw portion 7. Shank is inserted so as to be freely inserted and removed.

A pull bolt 17 is screwed into the thread portion 7 of the tapered collet 8, and the pull bolt 17 is
A bevel gear 20 is formed at an upper portion of a screw bolt portion 18 that is screwed into the bevel 19 via a flange 19, and a bevel pinion (21) for driving is engaged (engaged) with the bevel gear 20. The drive bevel pinion 21 is inserted (accommodated) in a lateral hole 4A formed in the holder body 4, and the pinion 2
A tool engaging portion 22 such as a hexagon wrench is formed on the outer end surface of the drive device 1, and the drive bevel pinion 21 is externally operated and rotated about its axis via the bevel gear 20. By rotating the pull bolt 17 about this axis, the taper collet 8 is pushed and pulled in the axial direction to expand and contract the tool holding hole 15 to grip and release the shank of the tool 3.

A portion of the lateral hole 4A from the opening end is formed as a screw hole, and a positioning member 23 is screwed into the screw hole so that the pinion 21 is in contact with the outer end surface of the pinion 21.
Is positioned to secure the engagement with the bevel gear 20, and the positioning body 23 has an operation space 23A for the tool engagement portion 22, so that even if the positioning body 23 is screwed, the outside of the pinion 21 is Can be operated.

When the positioning member 23 is screwed into the screw hole of the lateral hole 4A, it is desirable to use an adhesive (bond) to prevent loosening. A joint 23B is formed. The bevel gear 20 in the pull bolt 17 is centered by the lower end surface of the thrust bearing 24 abutting on the upper surface of the flange 19, and the thrust bearing 24 has a thick cylindrical portion 24A at the upper portion and a thin portion at the body portion 24B. And is fitted into a cavity 4B formed inside the axis of the holder body 4.

A screw hole 4C is formed in the shaft center portion of the holder main body 4 from the upper end to the vicinity of the cavity 4B, and a holding cylinder bolt 25 and a pull stud bolt 26 of the thrust bearing 24 are screwed into the screw hole 4C. The seal push-in bolt 27 is provided at the shaft center of the holding cylinder bolt 25 with a screw portion 27.
A is inserted through A. The lower portion of the holding cylinder bolt 25 is inserted into the cylindrical portion 24A of the thrust bearing 24 via a step, and a cylindrical collar 28 is interposed between the lower end surface of the bolt 25 and the upper end surface of the bevel gear 20. The collar 28 is fitted over the seal pushing bolt 27.

As shown in FIG. 2, the outer periphery of the collar 28 is in contact with the inner end surface of the bevel pinion 21, and a clamp bolt 29 is screwed into the holder body 4 from the lateral direction in opposition to the bevel pinion 21. The thrust bearing of the bevel pinion 21 is formed by pushing the collar 28 with the bolt 29. A seal ring 30 indicated by an O-ring inserted into a collar 28 is interposed between the lower end surface of the seal pushing bolt 27 and the upper end surface of the bevel gear 20.
By screwing the bolt 27 through a tool engaging portion 27B formed on the bolt 27, the seal ring 3
0 can be pressed.

The bolt 27 has an O.M.
Seal rings 31A and 32B indicated by O-rings are also mounted on the inner and outer circumferences of the seal ring 31 indicated by a ring and the thick cylindrical portion 24A of the thrust bearing 24. Necessary slit 24
C and a slit 24D for mounting a clamp bolt are formed, and a tool engaging portion 25A is formed on an upper portion of the holding cylinder bolt 25, and the bolt 25 substantially serves as a thrust bearing for the holder body 4. 24 and the like.

A first passage 29 penetrates the shaft of the pull stud bolt 26, a second passage 30 penetrates the shaft of the seal push bolt 27, and a shaft of the pull bolt 17. A third passage 31 is formed,
The pull stud bolt 26 is formed by these passages 29-31.
The center through coolant supply means 32 which sends coolant oil to the cutting edge of the small-diameter tool 3 as indicated by the arrow B is formed.

The shank of the small-diameter tool 3 can pass through the passage in the axial direction. In any case, the passage is used to send coolant oil at a high pressure of 70 kg · f / cm ² . Its diameter is a small hole of about 4 to 6 mm. According to the above configuration, the shank of the small-diameter tool 3 is inserted into the holding hole 15 of the tapered collet 8 and the tool engagement portion 22 is inserted.
The bevel pinion 21 is rotated in a predetermined direction by inserting a stick wrench into the.

This rotation is transmitted to the pull bolt 17 via the bevel gear 20, and the rotation of the pull bolt 17 causes the tapered collet 8 to be drawn inward (upward) of the collet holding hole 12, and the tapered portion 13 and the tapered surface 14. , The diameter of the holding hole 15 of the collet 8 is reduced, and the shank of the tool 3 is firmly gripped (gripped). Next, when the tool 3 is to be removed, the bevel pinion 21 may be rotated in the opposite direction to the above, and the collet 8 is forcibly moved relatively downward by the reverse operation, so that the shank of the tool 3 is gripped. Release it.

The configuration described above is an example of the embodiment, and the following design changes are free. For example, instead of attaching the adapter 6 with the bolt 5, an adapter fitting hole concentric with the main body is formed in the lower end surface of the holder body 4, and the adapter 6 is shrink-fitted into this fitting hole and cooled. The adapter 6 may be integrally connected to the holder body 4 by press-fitting by means such as fitting.

Although the bevel pinion 21 and the clamp bolt 29 are provided in the drive key groove 10 in FIG. 2, they may be provided at positions different from the groove 10.

[0028]

As described above in detail, according to the present invention, the chuck for small-diameter tool holding can have a center-through coolant lubrication function without any trouble, and the occlusal accuracy between the bevel pinion and the bevel gear is increased to enable high-speed rotation. There is no imbalance at the time, and therefore, the occurrence of vibration at the time of processing is prevented, so that more accurate processing can be performed.

[Brief description of the drawings]

FIG. 1 is an elevational sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main shaft 3 Small diameter tool 4 Holder main body 4A Side hole 6 Adapter 8 Taper collet 17 Pull bolt 20 Bevel gear 21 Bevel pinion 32 Center through coolant oil supply means

Claims (4)

[Claims] 1. A holder body (4) having a horizontal hole (4A) that rotates integrally with a main shaft (1) of a machine tool, an adapter (6) provided at a lower end of the holder body (4), A tapered collet (8) inserted into the adapter (6) and having a screw portion (7) at the top, a drive bevel pinion (21) housed in the lateral hole (4A), and the bevel pinion (21) A pull bolt (1) having a bevel gear (20) meshing with the screw portion (7) is screwed to the screw portion (7).
7), and the driving bevel pinion (21) is rotated about this axis, and the pull bolt (17) is rotated about this axis via a bevel gear (20) to thereby form a taper collet (8). ), The coolant oil is sent from the pull stud bolt (26) mounted on the upper axis of the holder body (4) to the cutting edge of the small diameter tool (3). Center through coolant refueling means (3
A chuck for holding a small-diameter tool, comprising: 2. The center through coolant supply means (32) according to claim 1, wherein the first passage (29) penetrating the axis of the pull stud bolt (26) and the bevel gear (2).
The second passage (3) penetrating through the axial center of the push bolt (27) for pressing the seal ring (30) against the upper end surface of the second passage (3).
The chuck for holding a small-diameter tool according to claim 1, characterized in that the chuck has at least a first passage (0) and a third passage (31) penetrating the axis of the pull bolt (17). 3. A holder body (4) is provided with a clamp bolt (29) facing the drive bevel pinion (21),
3. A small-diameter tool holder according to claim 2, wherein the thrust bearing of the drive bevel pinion (21) is obtained by abutting the clamp bolt (29) on a collar (28) fitted on the push bolt (27). Chuck. 4. A tool engaging portion (22) for rotating the pinion (21) about its axis is formed at an outer end of the drive bevel pinion (21). A positioning body (23) having an operation space (23A) for the joint portion (22) is screwed into the lateral hole (4A) in a state of contacting the outer end surface of the pinion (21). The chuck for holding a small-diameter tool according to claim 1.