JPH0131363Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a collet chuck for attaching tools such as drills and end mills to the rotating spindle of various machine tools.

(Conventional technology) The collect chuck that has been widely used in the past is
A chuck body with a deep tapered hole at the tip,
It consists of a collet having a tapered surface on its outer circumferential surface that is removably fitted into the deep tapered hole, and a tightening nut that is fitted onto the collet and removably screwed onto the chuck body. The diameter can be reduced by having split grooves cut along the axial direction alternately from both the distal and distal sides,
When the tightening nut is tightened, the collet is force-fitted into the deep tapered hole, and at the same time, the diameter of the collet is reduced, and the tool inserted therein is tightened and fixed.

In such a collet chuck, in order to extract the collet from the tapered hole of the chuck body in conjunction with the axial movement accompanying the loosening operation of the tightening nut, the outer peripheral surface of the tip end of the collet 1 must be An annular groove 2 is provided in the annular groove 2 to form an outward flange portion 3 at the tip, and an inward flange portion 5 is formed on the inner circumferential surface of the tightening nut 4, as shown by the dashed line in the figure. The collet 1 and the tightening nut 4 may be connected by engaging the inward flange portion 5 therein.

By the way, the tools that can be mounted on the chuck are limited to those whose mounting shaft diameter is compatible with the diameter reduction range of the inside diameter of the collet due to tightening of the tightening nut. It is necessary to replace it with one with an inner diameter that corresponds to this. In this case, in the configuration as shown in FIG. 8, in order to attach and detach the collet 1 and the tightening nut 4, at least the maximum outer diameter d ₁ of the outward flange 3 and the inner diameter D ₁ of the inward flange are required. It is necessary to reduce the diameter of the entire collector 1 by a diameter difference _S1 . However, as mentioned above, in order to extract the collet 1 from the chuck body in conjunction with the axial movement of the tightening nut 4, an engagement clearance is required between the flanges 3 and 5 even when the collet 1 is at its minimum diameter. Therefore, the above-mentioned diameter difference S ₁ is set to be quite large, and therefore, a very large force is required for the above-mentioned diameter reduction to attach and detach the collet and the tightening nut 4, and it is necessary to change the tool. It is extremely difficult to replace only the collector.

Therefore, in order to solve the above-mentioned problems, for example, as shown in Japanese Utility Model Publication No. 56-7366, an eccentric rib is provided on the inner peripheral surface of the tightening nut, and the diameter of the collet is slightly reduced or the diameter of the collet is reduced. A collet chuck has been proposed that can be press-fitted into a tightening nut while being rotated at a somewhat inclined position, and configured such that the eccentric rib partially engages in an annular groove provided on the outer circumferential surface of the collet.

(Problem to be solved by the invention) However, when an eccentric rib is provided on the inner peripheral surface of the tightening nut as proposed above, the amount of diameter reduction when the collet is attached and detached is smaller than that in the configuration shown in Fig. 8. Although it can be done with less weight, the center of gravity is shifted from the axis of rotation due to the eccentric rib, resulting in poor balance, which causes vibrations due to high-speed rotation during machining, which is a fatal problem in precision machining, and the collet attachment/detachment operation. It is also difficult to use and requires skill.

This idea was made to solve these problems, and it has a good overall balance and is highly suitable for precision machining, and it also allows the collet and tightening nut to be easily attached and detached with a small amount of force. The purpose is to provide a corrective check that can be carried out.

(Means for Solving the Problems) The collect chuck according to this invention has a chuck main body 11 having a deep tapered hole 11b on the distal end side.
and a collet 12 which can be retracted in diameter and has a tapered surface 12a on its outer circumferential surface that is removably fitted into the deep tapered hole 11b; and a tightening nut 13 that is screwed and compressed to force-fit the collet 12 into the deep tapered hole 11b to reduce its diameter.
has an outward flange portion 16 concentric with its axis on the outer circumferential surface of its tip, the tightening nut 13 is fitted on its inner circumferential surface, and the collet 12 is press-fitted into the deep tapered hole 11b of the chuck body 11. The inward flange portion 18 has an inner diameter smaller than the minimum outer diameter of the outward flange portion 16 when the outer flange portion 16 is reduced in diameter.
Notches 19, 19 are formed at radially opposite positions of the inward flange portion 18, and both the notches 19, 19
The radial distance between them is set to be larger than the maximum outer diameter of the outward flange portion 16 when the collet 12 is opened from the tapered hole 11b of the chuck body 11.

(Example) Hereinafter, an example of this invention will be described based on the drawings.

1 to 5, 11 is a chuck main body having a tapered shank portion 11a at the distal end and a deep thin tapered hole 11b inside the distal end side; 12 is a collet having a deep thin tapered surface 12a on the outer peripheral surface;
3 is a tightening nut that is removably connected to the collet 12 and removably screwed onto the chuck body 11.

The collet 12 has a substantially cylindrical shape with a tool insertion hole 12c concentric with its axis on the inside, and has eight split grooves 14, 14, cut along the axial direction formed alternately from the distal end to the distal end. It is equally divided into 8 pieces on both ends by the same method, and an annular groove 15 is provided on the outer peripheral surface of the tip, thereby forming an outward flange portion 16 concentric with the axis of the collet 12 at the tip. . Note that one side surface of this flange portion 16 is formed to be perpendicular to the axis of the collect 12 in order to form the inner wall of the annular groove 15, but the other side surface is formed as a tapered surface 12b having an inclination opposite to that of the tapered surface 12a. is formed.

The tightening nut 13 has a male threaded portion 1 carved on the outer circumferential surface of the distal end of the chuck body 11 on the inner circumferential surface of the proximal end.
A female threaded portion 13a is formed to be screwed into the collet 1c, and a tapered surface 13b having the same inclination angle as the tapered surface 12b on the distal end side of the collet 12 is provided on the inner circumferential surface on the distal end side. An annular groove 17 concentric with the axis of the nut 13 and an inward flange portion 18
are sequentially formed, and cutout portions 19, 19 having an angular width of approximately 90° are provided at radially opposing positions of the flange portion 18.

The collet 12 and the tightening nut 13 are such that the inward flange portion 18 of the tightening nut 13 engages in the annular groove 15 of the collet 12, and the outward flange portion of the collet 12 engages in the annular groove 17 of the nut 13. They are connected in a state in which the portion 16 is engaged. The taper surface 1 of the collet 12 in this connected state
2a into the deep tapered hole 11b of the chuck body 11, and then tighten the tightening nut 13 into the chuck body 11.
By tightening, the collet 12 is pressed against the tapered surface 13b of the nut 13 at its distal end side taper surface 12b, and as the width t of each split groove 14 decreases, the diameter of the collet 12 is reduced as a whole, and the collet 12 is inserted into the deep narrow taper hole 11a. It is pressed deep inside. Therefore, by inserting the mounting shaft portion of the tool into the tool insertion hole 12c of the collet 12 and performing the above-mentioned tightening operation, the tool is tightened and fixed by the reduced diameter of the insertion hole 12b.

Here, the inner diameter D ₁ of the inward flange portion 18 of the tightening nut 13 is larger than the outer diameter, that is, the minimum outer diameter d ₂ of the outward flange portion 16 of the collet 12 in the maximum tightened state of the nut shown by the solid line in FIG. It is set small. In other words, since D ₁ <d ₂ in the maximum tightened state, both flange portions 16,
Since an engagement clearance l=(d ₂ −D ₁ )/2 is generated between the bolts 18 and 18, by loosening the nut 13 from this state, the collet 12 is automatically inserted into the deep taper hole 1.
1b. In addition, the tightening nut 13
The radial distance D ₂ between the notches 19 and 19 in the flange portion 18 of the collet 1 in the state before tightening of the nut shown by the dashed line in FIGS. 1 and 5 is
The outer diameter of the outward flange portion 16 of No. 2, that is, the maximum outer diameter
d is set larger than ₁ . In other words, these dimensional relationships are D ₂ > d ₁ > d ₂ > D ₁ , and even when the outward flange portion 16 has the minimum outer diameter d ₂ , the collet 12 has a gap between each groove 14. It is set so that it does not reach the critical diameter. Therefore, the minimum outer diameter d ₂ of the outward flange portion 16 in the present invention is defined as the minimum outer diameter d 2 of the outward flange portion 16 when the chuck body 1 is
The chuck body 11 is press-fitted into the taper hole 11b of 1.
This is the so-called outer diameter when the tool mounting shaft is tightened and fixed, and of course, when the tool mounting shaft is not inserted into the tool insertion hole 12c, it will contract further than the minimum outer diameter d ₂ referred to in the present invention. and tighten the tightening nut 1 as described below.
When the inward flange part 18 of No. 3 is fitted into the annular groove 15 by climbing over the outward flange part 16 of the collet 12 in a so-called "squeezing" manner, the outward flange part 16 naturally has a diameter larger than the maximum outer diameter d ₂ . Shrink.

For the collect chuck with the above configuration, the 6th
As shown in the figure, the collet 12 can be easily attached to and detached from the tightening nut 13 in a so-called lock-and-pull manner.
In other words, since D ₂ > d ₁ , for example, when connecting, the collet 12 is in a slightly inclined position and most of the outward flange portion 16 is tightened by the tightening nut 13.
It can be inserted between the notches 19 and 19 on the annular groove 17 side. Next, the inward flange part 1 on one side
When the outward flange part 16 is engaged with the outer flange part 8, there will be an excess length m between the other inward flange part 18 and the outward flange part 16. As a result, the entire outward flange portion 16 is completely formed into the annular groove 17 by reducing the diameter of the collet having a length m by the radial direction transformation value _S2 .
It will fit inside and the connection will be completed. Amount of diameter reduction in this case
S ₂ is significantly smaller than the amount of diameter reduction S ₁ required for connection in the configuration shown in FIG. 8, and as shown in FIG. Only 4 pieces, 2 pieces facing each other, are S ₂ /
Since it only needs to be displaced by 2, easy and reliable attachment and detachment is possible with very little force. In the configuration shown in FIG. 8, it is impossible to use the above-mentioned dowel type connecting means because the flange portion 5 of the tightening nut 4 does not have a notch.

In the above embodiment, the collet 12 has a structure in which both ends are divided into 8 sections, but it goes without saying that in this invention, a collet with other numbers of sections, such as 3, 4, or 6 sections, can be used as well. stomach. Further, the flanges of the collet and the tightening nut may be protruded without an annular groove, and the inward flange portions of the tightening nut do not necessarily need to be formed to have exactly the same protrusion amount. There may be a slight difference in the amount of protrusion to the extent that precision machining is not hindered.

(Effects unique to the invention) In the collet chuck according to this invention, a notch is formed at a radially opposite position of the inward flange provided on the inner peripheral surface of the tightening nut, and the radial distance between the two notches is Since the diameter is set larger than the maximum outer diameter of the outward facing flange of the collet, the tightening nut and collet can be attached and detached extremely easily by a so-called "kendon-style" operation in which both flanges are engaged with each other and rotated. This is possible with just a little force. Moreover, since the above-mentioned notches are provided at positions facing each other in the radial direction, the center of gravity of the tightening nut does not shift from the axis of rotation, the overall balance of the collector chuck is good, there is no risk of vibration even when rotating at high speed, and precision machining is possible. suitable for

Moreover, according to the present invention, the inward flange on the inner peripheral surface of the tightening nut is smaller than the outward flange when the collet is press-fitted into the deep tapered hole of the chuck body and its diameter is reduced. Since it is formed on the inner diameter, an engagement margin is created between both flanges, and when loosening the tightening nut, the nut does not separate from the collet during rotation, and the collet can be smoothly attached to the chuck body. It can be extracted from the deep tapered hole.

[Brief explanation of the drawing]

Figures 1 to 7 show an embodiment of this invention, in which Figure 1 is a longitudinal sectional view of the tightening nut in a relaxed state, and Figure 2 is a cross-sectional view taken along the - line in Figure 1. 3 is an end view of the collet as seen from the distal end, FIG. 4 is an end view of the tightening nut as seen from the proximal end, and FIG. 5 is a longitudinal sectional view of the tightening nut in its maximum tightened state. Fig. 6 is a longitudinal sectional view showing the connection operation of the collet and the tightening nut, Fig. 7 is a schematic end view showing the behavior of the collet during the above connection operation, and Fig. 8 is a collet and a tightening nut in a general collet chuck. FIG. 6 is a longitudinal sectional view showing a connection operation with a tightening nut. 11...chuck body, 11b...deep tapered hole, 12...collection, 12a...tapered surface, 1
3...Tightening nut, 16...Outward flange, 18...Inward flange, 19...Notch, _D1 ...Inner diameter of inward flange, _D2 ...Diameter between the notches Directional distance, d ₁ ... Maximum outer diameter of the outward flange of the collet, d ₂ ... Minimum outer diameter of the outward flange of the collet.

Claims (1)

[Scope of utility model registration request] A chuck main body 11 having a deep tapered hole 11 on the distal end side, a collet 12 capable of reducing its diameter and having a tapered surface 12a on its outer peripheral surface that is removably fitted into the deep taper hole 11b, and this collet 12. The chuck body 11 is removably connected to the chuck body 11 and is removably screwed to the chuck body 11 so that the collet 1 can be tightened.
and a tightening nut 13 that press-fits the collet 2 into the deep tapered hole 11b to reduce its diameter, and the collet 12 has an outward flange 16 on the outer circumferential surface of the distal end thereof, which is concentric with its axis, The above tightening nut 13
is an inward flange portion having an inner diameter smaller than the minimum outer diameter of the outward flange portion 16 when the collet 12 is press-fitted into the deep tapered hole 11b of the chuck body 11 and its diameter is reduced. 18, and notches 19, 19 are formed at radially opposite positions of this inward flange portion 18, and both notches 1
The radial distance between 9 and 19 is set to be larger than the maximum outer diameter of the outward flange portion 16 when the collet 12 is opened from the tapered hole 11b of the chuck body 11.