JPH09295207A - Collet chuck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of slip of a work in the axial direction and the rotating direction even in the case where a large cutting force in the axial direction or the rotating direction is applied to the work by selecting a width of a recessed groove, which is provided on a holding surface, at the maximum groove width of the case where a contact surface, which is left on the holding surface by the wire discharging work, is eliminated. SOLUTION: This collet chuck is used for a lathe machine or the like, and has plural recessed grooves 16 in the axial direction of a holding surface 10 for holding a work. Width (w) of the recessed groove 16 on the holding surface 10 is set at the maximum groove width wMAX of the case where a contact surface, which is left on the holding surface 10 by the wire discharging work, is eliminated. For example, the groove 16 is formed by using wire discharging work so as to eliminate the surface of the holding surface 10, which is formed in a cemented carbide part 17 of a cylindrical collet chuck 3a, with a discharging wire at ϕ of diameter. When one groove 16 is formed, a discharging wire is fed in the circumferential direction by one feeding pitch, and the following groove 16 having the maximum groove width wMAX is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a collet chuck, and more particularly, to a gripping surface for a collet chuck used for gripping a workpiece in a lathe machine or the like for gripping the workpiece without slipping. Is related to the structure of.

[0002]

2. Description of the Related Art FIG. 7 is a diagram showing a main part of a conventional lathe. FIG. 8 is a view showing a conventional collet chuck 3 and a main shaft 2. FIG. 9 is a view showing a cross section taken along the line AA of the collet chuck 3 and the main shaft 2 in FIG.
FIG. 10 is a view showing various shapes of the groove and the contact surface 15 of the grip surface of the conventional collet chuck.

In FIG. 7, reference numeral 100 is a lathe for processing a workpiece such as metal, 1 is a headstock, 2 is a spindle, 3 is a collet chuck, 4 is a workpiece, 6 is a carriage, 7 is a tool holder, 8 is a bite stop lever, 9 is a bite, and 20 is an operation panel. The headstock 1 is a part that houses a motor for rotating the spindle 2, the collet chuck 3, a control device thereof, and the like. In FIGS. 8 and 9, 2 is a spindle, 3 is a collet chuck, 4 is a workpiece, 5 is a hole formed in the center of the collet chuck 3, 11 is an inclined portion of the collet chuck 3, and 12 is a collet of the spindle 2. It is an inclined portion of the hole corresponding to the chuck 3. In FIGS. 9 and 10, 17 is a cemented carbide portion.

The operation of the conventional lathe 100 will be described below. First, the workpiece 4 to be processed is inserted into the hole 5 of the collet chuck 3, and the workpiece 4 is fixed to the collet chuck 3 using the operation panel 20. After that, operation panel 2
The spindle 2 is rotated by 0, and the work 4 is cut, threaded, drilled, or the like by using the cutting tool 9. The bite 9 is inserted into a hole formed in the bite base 7 and fixed to the bite base 7 by a bite stop lever 8. The workpiece 4 fixed to the collet chuck 3 is processed by the cutting tool fixed to the cutting tool table 7. The carriage 6 is a base for moving the cutting tool 9 in parallel (axial direction) with respect to the workpiece 4. Actually, there is also a mechanism for moving the cutting tool 9 in a direction perpendicular to the work piece 4 and in an oblique direction, but a description thereof is omitted because it is not directly related to the present application.

The principle of fixing the workpiece 4 to the collet chuck 3 will be described in more detail with reference to FIGS. 8 and 9.
The collet chuck 3 is a tool that is coupled to the spindle 2 that is attached to the spindle stock 1 and that fixes the workpiece 4.
To fix the work piece 4 to the collet chuck 3, as shown in FIG.
As shown in FIG. 9, the workpiece 4 is inserted into the hole 5 of the collet chuck 3, and an internal device (not shown) controlled by the operation panel 20 pulls the collet chuck 3 in the direction of the arrow. By this drawing, the slanted portion 11 of the collet chuck 3 divided into three parts becomes the slanted portion 1 of the hole of the spindle 2.
Narrowed by 2, the workpiece 4 is fixed in the hole 5 of the collet chuck 3.

In FIG. 10, a portion other than the groove provided on the gripping surface 10 is called a contact surface 15, and this contact surface 15 is a surface which serves as a slip stopper for fixing the workpiece 4 to the collet chuck 3. is there. 10A shows the groove 13 and the contact surface 15 provided in the lateral direction of the collet chuck 3, and FIG. 10B shows the groove 14 and the contact surface 15 provided in the longitudinal direction of the collet chuck 3. FIG. 10C shows the grooves 13 and 14 provided in the horizontal and vertical directions of the collet chuck 3 and the contact surface 15 between these grooves. The workpiece 4 is fixed to the collet chuck 3 by these contact surfaces 15. As described above, in the conventional lathe processing, the gripping surface 10 has the groove 13 provided in the lateral direction and / or the groove 14 provided in the longitudinal direction.
The workpiece 4 is gripped by the contact surface 15 which is a portion other than the above, and the workpiece 4 is prevented from slipping from the collet chuck 3.

[0007]

However, when a cutting force in the axial direction and the rotational direction acts on the gripping surface 10 of the collet chuck 3, the work piece 4 moves in the axial direction and the rotational direction with respect to the collet chuck 3. It had the drawback of slipping in. In particular, when the cutting tool 9 is deeply bitten into the workpiece 4 and the cutting tool 9 is moved toward the collet chuck 3 at a high speed, the workpiece 4 tends to start sliding in the axial direction and the rotation direction of the collet chuck 3. Was great. For this reason, there has been a drawback that the accuracy of the products (for example, bearings, electronic components, clock shaft) processed by the processed product 4 varies in the length direction. This is considered to be based on the reason that the workpiece 4 is gripped by the contact surface 15 in the conventional technique.

An object of the present invention is to determine the width of the groove so that the width of the contact surface on the gripping surface is approximately 0, so that even if a large axial and rotational cutting force acts on the workpiece. , To provide a collet chuck in which the work piece does not slip in the axial and rotational directions.

[0009]

SUMMARY OF THE INVENTION The present invention is a collet chuck used in a lathe machine or the like and having a plurality of concave grooves in the axial direction of the grip surface of a collet chuck for gripping a workpiece. The groove width w is the maximum groove width w when there is no contact surface left on the grip surface by wire electric discharge machining.
Selected for _MAX .

Further, the collet chuck of the present invention is formed such that the width t of the contact surface on the gripping surface is 10% or less of the maximum groove width w _MAX .

Further, in the collet chuck of the present invention, the groove width w on the gripping surface is 90% or more and 100% or more of the maximum groove width w _MAX.
It is formed as follows.

Further, in the collet chuck of the present invention, the concave groove on the gripping surface is formed in a triangular shape so that the contact surface remaining on the gripping surface by wire electric discharge machining is eliminated.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1. FIG. 1 is an end view of a collet chuck viewed from a direction in which a workpiece is inserted according to Embodiment 1 of the present invention. FIG. 2 is a perspective view of a gripping surface of a collet chuck 3a, which is one of the three divided ends of the collet chuck 3 according to the first embodiment of the present invention. FIG. 3 is an end face enlarged view of a portion showing the vicinity of the gripping surface of collet chuck 3a according to the first embodiment of the present invention. In FIG. 1, 3a, 3
b and 3c are collet chucks of the three-divided collet chuck 3, and the gripping surface 10 provided on the cemented carbide portion 17 of each of the divided collet chucks has the details shown in FIGS. As shown in FIG.
Is configured. The groove 16 according to the present invention is formed in the vertical direction over substantially the entire grip surface 10 as shown in FIGS. 2, 3, and 5.

The structure of the groove according to the present invention will be described in detail with reference to FIG. In FIG. 3, reference numeral 16 denotes a vertical groove formed by wire electric discharge machining the surface of the cemented carbide portion 17. The groove 16 removes the surface of the gripping surface 10 formed on the cemented carbide portion 17 of the collet chuck 3 formed in a cylindrical shape by an electric discharge wire having a diameter φ using, for example, wire electric discharge machining. Is formed by At this time, the groove 16 formed
Is w. The width w of the groove 16 can be determined by how close the discharge wire is to the gripping surface 10. By setting the distance between the electric discharge wire and the gripping surface 10 at the time of initial setting of the wire electric discharge machine, the electric discharge wire can be sequentially placed at the feed pitch width S to form a constant width w of the groove 16. . The maximum groove width formed in this way is called the maximum groove width w _MAX . That is, one groove 1
6 is formed, the discharge wire is then fed in the circumferential direction by the feed pitch S, and the next groove 16 having the maximum groove width w _MAX is formed.
Is formed.

In this way, by changing the feed pitch S of the discharge wire and the diameter φ of the discharge wire, the groove 1
Width w of 6 and contact surface 1 formed between grooves 16
The width t of 5 can be arbitrarily changed. here,
The contact surface 15 is the remaining portion after removing the groove 16 from the gripping surface 10 processed into a cylindrical shape. Next, the relationship between the feed pitch S of the discharge wire, the width w of the groove 16 and the width t of the contact surface 15 formed between the grooves 16 will be described with reference to FIG. FIG. 5 is a diagram showing the shape of the gripping surface when the diameter φ of the discharge wire and the feed pitch width S of the gripping surface of the collet chuck are changed.

In FIG. 5A, for example, the diameter φ of the discharge wire is 250 μm (hereinafter sometimes referred to as μ), and the feed pitch width S of the discharge wire is 370 μm which is larger than the diameter φ of the discharge wire. FIG. By performing the wire electric discharge machining under such conditions, the width w of the groove 16 becomes about 200 μm, but the width t of the contact surface 15 at this time becomes about 170 μm.
The groove width w of the groove 16 at this time is the maximum groove width w _MAX . As described above, when the feed pitch width of the discharge wire is larger than the diameter φ of the discharge wire, the contact surface 15 having the width t is always held on the grip surface.
Is formed. The width t of the contact surface 15 is the feed pitch width S.
From the maximum groove width w _MAX of the groove 16. That is, it is represented by t = S−w _MAX .

FIG. 5B is a diagram when the diameter φ of the discharge wire is 250 microns and the feed pitch width S of the discharge wire is 200 microns, for example. When wire electric discharge machining is performed under such conditions, the groove width w of the groove 16 becomes approximately 200 μm, and at this time, the width t of the contact surface 15 is t.
Becomes almost zero. The groove width of the groove 16 at this time is also the maximum groove width w.
_MAX . In this way, when the appropriate feed pitch S is selected in relation to the diameter φ of the discharge wire, the groove 16 and the groove 16
It is possible to perform wire electric discharge machining so that no contact surface remains between them.

FIG. 5C shows a case where the diameter φ of the discharge wire is 250 μm and the feed pitch width S of the discharge wire is 100 μm. When the wire electric discharge machining is performed under such conditions, the groove width w of the groove 16 becomes about 100 microns, and at this time, the width t of the contact surface 15 is t.
Is completely zero. The groove width w of the groove 16 at this time is 100 μ less than the maximum groove width w _MAX of 200 μ.
It becomes 00μ. That is, in the case of kno, the groove width w of the groove 16
Is 50% of the maximum groove width w _MAX . Thus, when the feed pitch S smaller than the diameter φ of the discharge wire is selected, wire electric discharge machining that forms a shape with a narrow groove width without leaving a contact surface between the grooves 16 can be performed. Done. In this case, the depth of the groove 16 also becomes shallow as shown in FIG.

FIG. 6 is an experimental diagram showing the relationship between the feed pitch width S of the discharge wire and the maximum gripping force F when the workpiece begins to slide on the gripping surface of the collet chuck. In FIG. 6, a indicates that the discharge wire feed pitch width S is 100 μ, and the width w of the groove 16 is about 100 μ at that time (corresponding to FIG. 5C). At that time, the maximum gripping force F when the workpiece started to slide was 18 kg.

6b, the discharge wire feed pitch width S was 200 μ, and the maximum gripping force F when the workpiece started to slide was 24 kg. In this case, groove 1
The width w of 6 is about 200 μ, and the width t of the contact surface 15 is just 0 μ (corresponding to FIG. 5B). This point and its periphery correspond to the case of the present invention.

In FIG. 6, c, the feed wire pitch S of the discharge wire was 370 μ, and the maximum gripping force F when the workpiece started to slide was 19 kg. In this case, groove 1
The width w of 6 is about 200 μ, and the width of the contact surface 15 is about 17 μm.
It shows a state of 0 μ (corresponding to FIG. 5 (A)).

6d, the feed wire pitch S of the discharge wire was 730 .mu.m, and the maximum gripping force F when the workpiece started to slide was 19 kg. In this case, groove 1
The width w of 6 is about 200 μ, and the width of the contact surface 15 is about 53 μm.
The state is 0 μ (no correspondence diagram).

6e, the feed pitch width of the discharge wire was 1220 μ, and the maximum gripping force when the workpiece started to slip was 18 kg. In this case, the groove 16
Has a width w of about 200μ, and the contact surface 15 is about 1020μ
Is shown (no correspondence diagram).

Reference character f in FIG. 6 indicates that the groove is not machined by the discharge wire at all, that is, the contact surface 15 is very wide like the conventional gripping surface 10, and the workpiece at that time starts to slide. The maximum gripping force was 14 kg (no correspondence diagram).

As can be seen from the above experiment, the groove width w of the groove 16 and the width t of the contact surface 15 can be variously changed depending on the diameter φ of the discharge wire and the feed pitch width S of the discharge wire, but it is concluded from FIG. As described above, in the above-mentioned experiment, when the feed pitch width S of the discharge wire is selected to be approximately 200 μ, the maximum gripping force F when the workpiece starts to slide becomes maximum. In other words, this is the width t of the contact surface 15.
The maximum gripping force F will be obtained when is approximately 0 and in the vicinity thereof. More specifically, it can be inferred from experiments that the gripping force becomes large when the width t of the contact surface 15 is within ± 20 μ when the diameter φ of the discharge wire is 250 μ. Here, when the width t of the contact surface 15 is negative, it means that the groove width w of the groove 16 is narrowed by the value t from the maximum groove width w _MAX . For example, in this example, when the width t of the contact surface 15 is minus 10 μ, the groove width w is the maximum groove width 2
This means 190 μ, which is 10 μ smaller than 00 μ.

As described above, according to the present invention, the width t of the contact surface 15 is set to be substantially 0, so that the contact with the workpiece 4 can be surely secured, whereby the workpiece 4 can be moved in a large axial direction and It is possible to prevent the workpiece 4 from slipping in the axial direction and the rotational direction even if a cutting force in the rotational direction is applied.

Embodiment 2. FIG. 4 is a diagram showing an enlarged end surface of the gripping surface of the collet chuck according to the second embodiment of the present invention. FIG. 4 shows an embodiment in which the groove 16 is formed in a triangular shape. Also in this case, the width of the contact surface 15 can be made zero. Such a groove 16 can also be formed by wire electric discharge machining as in the first embodiment.

Since the contact surface 15 is not formed on the gripping surface 10 as in the first embodiment by forming the groove 16 in the triangular shape as described above, the gripping surface is the same as in the first embodiment. The contact with the work piece 4 can be reliably ensured at 10, so that the work piece 4 is prevented from slipping in the axial direction and the rotation direction even when a large cutting force in the axial direction and the rotation direction is applied to the work piece 4. it can.

[0029]

According to the present invention, it is possible to prevent the work piece from slipping in the axial direction and the rotation direction even when a large axial and rotational cutting force acts on the work piece. Therefore, the feed rate of the cutting tool in the axial direction can be increased. Also,
Since the work piece does not slip in the axial direction, the processing variation of the product can be reduced.

[Brief description of drawings]

FIG. 1 is an end view of a collet chuck viewed from a direction in which a workpiece is inserted according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a gripping surface of the collet chuck according to the first embodiment of the present invention.

FIG. 3 is an enlarged end view of a portion showing the vicinity of a gripping surface of the collet chuck according to the first embodiment of the present invention.

FIG. 4 is a diagram showing an enlarged end surface of a gripping surface of a collet chuck according to a second embodiment of the present invention.

FIG. 5 is a diagram showing the relationship between the diameter φ of the discharge wire on the gripping surface of the collet chuck, the discharge wire feed pitch width S, and the shape of the gripping surface.

FIG. 6 is an experimental diagram showing a relationship between a discharge wire feed pitch width S in wire electric discharge machining of a collet chuck and a maximum gripping force F when a workpiece starts to slip.

FIG. 7 is a view of a main part of a conventional lathe viewed from an oblique direction.

FIG. 8 is a view of a collet chuck and a main shaft used in a conventional lathe as seen from an oblique direction.

FIG. 9 is a cross-sectional view of a collet chuck and a spindle used in a conventional lathe.

FIG. 10 is a diagram showing shapes of various gripping surfaces of a conventional collet chuck.

[Explanation of symbols]

1 ... Spindle base, 2 ... Spindle, 3,3a, 3b, 3c ... Collet chuck, 4 ... Workpiece, 5 ... Hole, 6 ... Reciprocating carriage, 7 ... Tool holder, 8 ... Tool stopper lever, 9 ... Tool, 10 ... Gripping surface, 11, 12 ... Inclined part, 13, 14, 16 ... Groove, 15
… Contact surface, 17… Cemented carbide part, 100… Lathe

Claims (4)

[Claims] 1. A collet chuck having a plurality of concave grooves formed by wire electric discharge machining in the axial direction of a gripping surface of a collet chuck for gripping a workpiece, which is used in a lathe machine or the like: width of the concave groove on the gripping surface. w is the maximum groove width w when there is no contact surface left on the gripping surface due to wire electric discharge machining
Collet chuck characterized by being selected for _MAX . 2. The collet chuck according to claim 1, wherein the width t of the contact surface on the gripping surface is the maximum groove width w _MAX.
Collet chuck, characterized in that it is formed to be 10% or less. 3. The collet chuck according to claim 1, wherein the groove width w on the gripping surface is 90 times the maximum groove width w _MAX .
%, A collet chuck, characterized in that it is formed so as to be at least%. 4. A collet chuck, which is used in a lathe machine or the like and has a plurality of concave grooves formed by wire electric discharge machining in the axial direction of a gripping surface of a collet chuck for gripping a workpiece: the shape of the concave groove on the gripping surface. Is a triangular shape, and is formed so that there is no contact surface left on the grip surface by wire electric discharge machining.