JPH081763Y2 - Chuck - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention grips a cutting tool such as an end mill or a boring bar in a chuck hole of a chuck cylinder in which a rotary cylinder is annularly attached via a needle roller. To a chuck formed to

[Prior Art] There are various shapes of chucks that are attached to a spindle of a machine tool or the like, and are formed so as to hold a cutting tool or the like at their tips, but generally have the following structure. Is used relatively often. That is, a chuck body that forms a shank portion to be inserted into a taper hole of a main shaft on a proximal end side and a chuck cylinder having a chuck hole for gripping an object such as the cutting tool on a distal end side, and the chuck body. The rotating cylinder and the like are attached to the outer circumference of the chuck cylinder via a needle roller. The outer surface of the chuck cylinder that comes into contact with the needle roller is formed in a taper shape whose diameter decreases toward the tip. Known techniques of the chuck having the above basic structure include those disclosed in Japanese Utility Model Publication Nos. 59-24407 and 64-3602. However, a chuck having a structure in which a rotary cylinder is ring-attached to the tapered outer surface of the chuck cylinder via a needle roller and the rotary shaft is rotated to reduce the diameter of the chuck hole of the chuck cylinder to grasp an object such as a cutting tool is generally used. Has been widely used as a publicly known technique in the past.

Many of the chuck holes of the chuck are formed with a groove for securely gripping a cutting tool or the like. There are many conventional techniques for forming the groove. For example,
JP-B 57-23055, JP-B 58-15043, JP
58-56086, 58-143108, 58-14
No. 3107, No. 59-156710, No. 60-84202
Gazette, gazette 60-190509 gazette, gazette gazette 61-78509 gazette, gazette gazette 61-124303 gazette, gazette gazette 61-124304 gazette,
JP 61-124305, JP 59-33534, JP 64-42808, JP 63-193605, JP 63-
110307, 63-91305, 63-60502
The gazette, the gazette of Japanese Utility Model Laid-Open No. 62-46509, the gazette of Gazette of Japanese Laid-Open Sho 62-39905, the gazette of Gazette of Japanese Laid-Open Sho 61-191801, the gazette of Gazette of Japanese Laid-Open Sho 61-187638 are listed.

Each of the above-mentioned conventional techniques is characterized by the shape of the concave groove, but is different from the one according to the present application in structure and effect.

On the other hand, as a conventional technique of a chuck which is relatively similar to the device of the present application, the one disclosed in Japanese Utility Model Publication No. 56-22966 can be cited. In the prior art, a concave portion facing in the circumferential direction is formed on the inner peripheral wall (inner circumference of the chuck hole) of the chuck cylinder having the above-mentioned shape, and the concave portion is disclosed as shown in the drawings (FIGS. 1 and 2). Shows a plurality of rows of ring-shaped or spiral grooves.

[Problems to be Solved by the Invention] The object disclosed in Japanese Utility Model Publication No. 56-22966 is to securely grasp a tool and perform high-precision machining. I have a problem. That is, when a cutting tool or the like is gripped by the chuck, the distribution of the chuck gripping force along the chuck axis direction needs to increase from the back of the chuck barrel to the tip thereof. That is, it is necessary that the surface pressure of the chuck hole that comes into contact with the cutting tool or the like increases toward the tip of the chuck cylinder.

The reason is that when the gripping force of the cutting tool etc. is strong in the inner part of the chuck cylinder, the bending moment generated by the cutting resistance force generated during cutting becomes large, and conversely the gripping force is strong at the tip side of the chuck cylinder. This is because in this case, the bending moment becomes small and it becomes possible to exert a stronger grasping force. According to Japanese Utility Model Publication No. 56-22966, the concave portion is formed to improve the surface pressure of the inner wall of the chuck cylinder (inner circumference of the chuck hole), but the distribution of the grasping force as described above is taken into consideration. However, the structure is not such that the maximum gripping force is obtained at the tip side of the chuck cylinder.

The present invention has been made in view of the above circumstances, and increases the chuck gripping force from the back of the chuck cylinder toward the tip to generate the maximum gripping force on the tip side to further increase the chuck gripping force. An object of the present invention is to provide a chuck that is strong and can be implemented relatively inexpensively.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a needle on the outer surface of a chuck cylinder in which a taper that reduces in diameter toward the tip is formed on the outer surface and a chuck hole is provided therein. A chuck for ring-wrapping a rotary cylinder via a roller, rotating the rotary cylinder to reduce the diameter of the chuck hole to grip an object, and in the chuck hole along the inner circumference thereof and in the axial direction. The chuck is configured such that concave grooves are provided at appropriate intervals and the distance between the adjacent concave grooves is gradually reduced toward the tip of the chuck cylinder.

[Operation] When the rotary cylinder annularly attached to the chuck cylinder having the tapered surface is rotated, the needle roller interposed therebetween moves toward the diameter-expanding side toward the tapered surface, and the chuck cylinder is moved accordingly. Press to shrink the chuck hole. Since uneven grooves are formed in the chuck holes and the distance between the adjacent grooves becomes smaller toward the tip side of the chuck hole, the contact area of the shank portion of the cutting tool or the like that contacts the tip side. It becomes narrower as you go to, and the surface pressure increases accordingly. Therefore, the maximum surface pressure is obtained at the tip of the chuck cylinder, and the cutting tool or the like is strongly gripped by the tip of the chuck cylinder.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

First, the overall structure of the chuck 1 will be described with reference to FIG.

The chuck 1 is inserted into a tapered hole such as a main shaft (not shown),
A chuck body 6 including a tapered shank portion 3 formed on the base end side thereof, a chuck cylinder 4 formed on the tip end side, and a clamp portion 5 and the like formed on an intermediate portion thereof, and a ring attached to the chuck cylinder 4. The rotating cylinder 7 and the chuck cylinder 4 and the needle roller 8 interposed between the outer surface of the chuck cylinder 4 and the inner surface of the rotating cylinder 7. A chuck hole 9 into which a shank portion of an object such as a cutting tool is inserted is formed inside the chuck cylinder 4, and a taper surface whose diameter is reduced toward the tip side is formed on the outer periphery thereof.
10 are formed. The chuck hole 9 communicates with a through hole 11 penetrating the chuck body 6. The needle roller 8 is disposed in contact with the taper surface 10 of the chuck cylinder 4 and also in contact with the taper surface 12 of the inner surface of the rotating cylinder 7, and is held by the roller holding cylinder 13 and before and after the chuck cylinder 4 or rotating. A seal 14 or a seal 15 held on the cylinder 7 side is provided. In addition,
The seals 14 and 15 are held by stop rings 16 and 17, respectively.

A spiral groove 2 is recessed in the chuck hole 9 of the chuck cylinder 4. The spiral groove 2 is formed by forming a semi-circular recess 18 on the inner wall of the chuck hole 9 as shown in FIG. 2 (a), and extending spirally from the back of the chuck hole 9 toward the tip thereof. The pitch dimension Pi between the adjacent concave grooves is formed so as to gradually decrease toward the tip of the chuck cylinder 4. That is, if the pitch on the back side is P _n and the tip is P ₁ , then P ₁ <P _n . The difference between P ₁ and P _n , the number of spiral grooves 2 and the like are determined by the chuck 1
The size is appropriately set according to the size, the shape and size of the chuck hole 9. By forming the spiral groove 2 having the above-described shape in the chuck hole 9, the area of the non-recessed part of the spiral groove 2 becomes smaller toward the tip side of the chuck hole 9.

FIGS. 2 (a) to 2 (e) show some of the groove shapes recessed in the inner wall of the chuck hole 9 of the spiral groove 2. As shown in FIG.

As described above, FIG. 2A shows a semicircular arc-shaped concave portion 18 in the concave groove shape of the spiral groove 2 shown in FIG. 2 (b) is a rectangular recess 18a, and FIG. 2 (c) is a slit recess.
18b, FIG. 2 (d) shows a trapezoidal recess 18c, and FIG. 2 (e) shows a triangular recess 18d. Of course, the shape of the groove is not limited to the above, and any shape may be applied.

As shown in FIG. 3, a taper surface on the outer circumference of the chuck cylinder 4
The needle roller 8 is interposed between the taper surface 12 on the inner surface of the rotary cylinder 7 and 10 as described above. From this state, the rotary cylinder 7
When is rotated to the right, the needle roller 8 located at the position indicated by the solid line moves to the large diameter side of the tapered surface 10 of the chuck cylinder 4 as indicated by the chain double-dashed line, and the rotating cylinder 7 also moves to the large diameter side accordingly. Therefore, the tapered surface 10 is pressed in the state shown by the chain double-dashed line,
The chuck hole 9 is reduced in diameter by a dimension 2δ as shown by a chain double-dashed line. Therefore, the cutting tool or the like inserted into the chuck hole 9 is given a tightening margin of the dimension 2δ and is gripped.

On the other hand, since the distance between the spiral grooves 2 gradually decreases toward the tip side of the chuck cylinder 4, the chuck holes 9 between the adjacent concave grooves 9
The area of the contact surface becomes smaller toward the tip side. Therefore, the surface pressure applied to the cutting tool or the like when the chuck is tightened gradually increases from the back of the chuck cylinder 4 toward the tip, and becomes the maximum near the tip. Therefore, the cutting tool or the like is most strongly gripped by the tip portion of the chuck cylinder 4,
As a result, a stronger gripping force can be generated as compared with the conventional chuck.

FIG. 4 shows another embodiment in which an annular groove 20 is formed in the chuck hole 9 as the concave groove instead of the spiral groove 2. The annular grooves 20 are arranged in a plurality of rows side by side in the axial direction of the chuck hole 9, and the intervals between the adjacent grooves are formed at unequal pitches, and are formed so as to gradually decrease from the depth of the chuck hole 9 toward the tip.

According to this embodiment, the same effect as that of the above embodiment can be obtained. In the case of the annular groove 20, the shape of the concave portion provided in the inner wall of the chuck hole 9 is not limited to that shown in FIGS. 2 (a) and 2 (e). Is.

Further, as shown by the chain double-dashed line in FIG. 4, one or a plurality of vertical grooves 19 may be provided in the chuck hole 9 along the axial direction. The vertical groove 19 is the spiral groove 2 shown in FIG.
In this case, of course, they may be used together. The vertical groove 19 functions to reduce the contact area of the chuck hole 9 with the cutting tool or the like and increase the surface pressure, and the cutting oil or the like attached to the contact portion between the chuck hole 9 and the cutting tool or the like. It functions as an oil drain groove. Of course, the spiral groove 2 and the annular groove 20 described above also function as an oil drain groove.

In the above-mentioned embodiment, the twisting direction of the spiral groove 2 is not particularly limited, but it may be right twisting or left twisting. Further, it is desirable that the groove depth and the groove width of the spiral groove 2 and the annular groove 20 are constant for the convenience of machining, but it is not limited thereto. Further, a combination of the spiral groove 2 and the annular groove 20 may be used, and a combination of these with the vertical groove 19 may also be used. Further, the spiral groove is not limited to a single spiral groove as in the embodiment shown in FIG. 1 and may be a multiple groove, and the annular grooves are also formed by arranging a plurality of different shapes in parallel. Good. Also,
As shown in FIG. 1, the spiral groove 2 and the annular groove 20 may be formed up to the required position corresponding to the range in which the inner diameter shrinks, in addition to the one reaching the inner end of the chuck hole 9. In this case, an escape hole or the like may be formed at the end of the spiral groove 22 at the rear end of the cut to facilitate groove processing.

[Effect of the Invention] According to the present invention, the following remarkable effects are obtained.

1) Since a groove such as a spiral groove or an annular groove is formed in the chuck hole of the chuck cylinder from the back to the tip, the interval between the adjacent grooves is gradually reduced. Since the pressure distribution increases from the back to the tip of the chuck cylinder and reaches the maximum surface pressure near the tip, the gripping force of the chuck against a cutting tool, etc. also goes from the back to the tip of the chuck cylinder in proportion to the surface pressure distribution. Increase and become the largest near the tip. Therefore, it is possible to generate a large grasping force that opposes the cutting resistance when the object to be cut is cut with a cutting tool or the like. It is possible to obtain a stronger chuck gripping force than the conventional chuck.

2) The concave groove such as the spiral groove and the annular groove acts as an oil-draining groove for cutting oil or the like that adheres between the outer periphery of the shank portion of the cutting tool or the like and the chuck hole, and as a result, the inner peripheral wall of the chuck cylinder and the cutting tool or the like. The slippage due to oil between them and the like will be reduced, and the gripping force will be further increased.

3) The spiral groove, the annular groove, etc., can be carried out at a relatively low cost, since various shapes can be processed relatively easily by an NC lathe or the like.

[Brief description of drawings]

FIG. 1 is an axial sectional view of an embodiment of the present invention, and FIGS. 2 (a) to (e) are formed on the inner wall of a chuck hole having a concave groove such as a spiral groove or an annular groove formed in the chuck hole. FIG. 3 is a partial axial sectional view showing various sectional shapes of the concave portion, FIG. 3 is an enlarged sectional view for explaining the reduced diameter state of the chuck hole of the chuck according to the embodiment, and FIG. 4 is another embodiment of the present invention. It is a partial axial sectional view showing. 1 ... Chuck, 2 ... Spiral groove, 3 ... Shank part, 4
…… Chuck tube, 5 clamps, 6 …… Chuck body,
7 ... Rotating cylinder, 8 ... Needle roller, 9 ... Chuck hole, 10,12 ... Tapered surface, 13 ... Roller holding cylinder, 14,15 ...
… Seal, 16,17 …… Stop ring, 18 …… Semi-circular recess, 18a …… Rectangular recess, 18b …… Slit recess, 18
c: trapezoidal recess, 18d: triangular recess, 19: vertical groove,
20 ... annular groove.

Claims (2)

[Scope of utility model registration request] Claim: What is claimed is: 1. A rotary cylinder is attached to the outer surface of a chuck cylinder, which has a taper having a diameter decreasing toward the tip, and a chuck hole is formed therein, through a needle roller, and the rotary cylinder is rotated. And a chuck for gripping an object by reducing the diameter of the chuck hole, and in which adjacent grooves are provided along the inner circumference of the chuck hole and at appropriate intervals in the axial direction. A chuck characterized in that the interval between the concave grooves is gradually reduced toward the tip of the chuck cylinder. 2. The chuck according to claim 1, wherein the concave groove is a spiral groove or a plurality of rows of annular grooves.