JPH0351054Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a chuck that is provided for attaching a tool such as a drill or an end mill to the main shaft of a machine tool such as a machining center, milling machine, or drilling machine.

PRIOR ART As an example of the prior art of this type of chuck, there is one proposed by the applicant of the present invention in Japanese Utility Model Application Publication No. 183104/1983 (hereinafter referred to as the first conventional example). Where,
As shown in FIG.
is formed, and the chuck body 10 is attached to this threaded portion 202.
At the same time, the connecting nut 101 disposed inside the chuck body 100 is screwed into the connecting nut 101, and the engaging projection piece 102 protruding from the outer peripheral surface of the connecting nut 101 is passed through the axial guide opening 103 formed in the side wall of the chuck body 100. By engaging the inner circumferential surface of the tightening collar 104 relatively rotatably and immovably in the axial direction, and by rotating the tightening collar 104, the base of the collet 200 is connected via the connecting nut 101. The end portion is pulled axially inward of the chuck body 100, and the contractile force of the collet 200 generated at this time causes the tool 300 to be reliably held in the chuck body 100.

Further, there is another conventional technique shown in FIG. 6 (hereinafter referred to as the second conventional example). There, by rotating a tightening gear 400 attached to the chuck body 100 with a wrench 401, the collet 200, which has a bevel gear 402 connected to the base end that meshes with the tightening gear 400, is drawn into the chuck body 100, and the collet 200 is pulled into the chuck body 100. The tool 300 is reliably held in the same manner as described above by the contraction force of the collet 200 that occurs when the tool 300 is removed.

Problems to be Solved by the Invention However, in the case of the above-mentioned first conventional example, first of all, there are problems in that the number of parts increases and the structure becomes complicated.

Second, since the collet 200 is pushed into the chuck body 100 by the screw feeding mechanism,
Since the collet 200 will be pushed in eccentrically due to backlash caused by machining errors in the threaded part, the chuck body 10 will be pushed in with the tool 300 centered.
The problem is that it is difficult to set it to 0. Thirdly, since the tightening collar 104 is fastened, the outer diameter at the tip of the chuck body 100 becomes larger by that amount. There is a problem that such a deep hole cannot be machined because there is a risk that the hole may come into contact with the stepped portion.

Further, in the case of the second conventional example, although the third problem mentioned above can be solved, the first and second problems still exist because of the complicated gear mechanism.

The present invention has been made to solve the problems of the prior art, and has a simple structure, which allows the outer diameter of the tip of the chuck body to be reduced, and also allows the tool to be attached to the chuck body in a centered state. The purpose is to provide you with a chance to do so.

Another object of the present invention is to ensure reliable attachment of the collet to the chuck body.

Means for Solving the Problems The chuck according to the present invention has a proximal shaft connected to the main shaft of a machine tool, and has a hollow cylindrical portion provided at the distal end, and the chuck has a taper formed by expanding the diameter toward the distal end. a chuck main body having a hole; a chuck body inserted into the hollow cylindrical portion;
It has a collet that holds a tool inside, a tapered hole provided in the radial direction at the base end of the collet, and a tapered part corresponding to the tapered hole, and penetrates the hollow cylinder part in the radial direction, and is screwed into the collet. a screw-in type taper presser whose taper part is inserted into a tapered hole and pulls the collet into the hollow cylindrical part; an elastic body which elastically biases the collet toward the distal end in order to expand the collet; A portion of the hollow cylindrical portion located on the proximal end side of the collet is provided so as to penetrate the hollow cylindrical portion in the radial direction. It is characterized by comprising a rotating cam such that the proximal end of the collet faces the collet.

Function: When no tool is attached to the collet, the collet is urged toward the distal end by the elastic body and is in an expanded state. After the tool is inserted into the collet, by screwing in the pressing tool, its tapered part is pushed into the taper hole of the collet, and the collet is drawn into the hollow cylindrical part of the chuck body, reducing the diameter of the collet and pushing the tool out. hold. Loosen the pressing tool,
When the rotary cam is rotated, the notch surface slopes and pushes the collet toward the distal end, returning the collet to its expanded state.

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings.
Figure 1 is a longitudinal sectional view of the chuck according to the present invention, Figure 2
The figure is a view in the direction of arrow A in FIG. 1, and FIG. 3 is an exploded perspective view showing the structure around the proximal end of the collet.

The chuck body 1 has a base end shaft portion 10 that is attached to the main shaft of a machine tool such as a machining center, a milling machine, a drill press, etc., and a hollow cylinder portion 11 that is connected to the distal end side of the base shaft portion 10. The inner peripheral surface on the distal end side of the hollow cylindrical portion 11 is formed into a tapered hole 12 whose diameter increases toward the distal end side.

A collet 20 for holding a tool 30 such as a drill or an end mill is inserted concentrically into the hollow cylindrical portion 11 from the tip side. The collet 20 consists of a hollow cylindrical collet main body 21 in which eight grooves 22, 22, . It has a fastened shaft portion 23. The outer circumferential surface of the collet main body 21 on the distal end side is formed into a tapered portion 24 corresponding to the tapered hole 12. The base end of the shaft portion 23 has reached a position slightly deviated from the innermost part of the hollow cylindrical portion 11 toward the distal end side. There is a slight gap 1 between the inner circumferential surface of the intermediate part of the hollow cylinder part 11 and the outer circumferential surface of the collector body 21.
5 is provided. This gap 15 functions to prevent the collet 20 from coming into close contact with the chuck body 1 more than necessary when the collet 20 is inserted and connected to the chuck body 1 as will be described later.

It goes without saying that the collector body 21 and the shaft portion 23 may be formed integrally.

A fluoroset screw 4 is attached to the base end of the hollow cylindrical portion 11.
0 is provided in the radial direction. A tapered portion 41 is formed at the tip of the fluoroset screw 40, the diameter of which decreases toward the tip. This tapered portion 41 protrudes into the hollow cylindrical portion 11, and a receiving hole 25 is bored at a corresponding position in the shaft portion 23.
It is becoming more and more intrusive. The tip of the receiving hole 25 is formed into a tapered hole 26 corresponding to the tapered portion 41 . The hole center 27 of the receiving hole 25 is selected so that it is slightly offset toward the distal end side from the center of the screw hole 13 when the collet 20 is inserted into the chuck body. Therefore, collection 2
0 is inserted into the screw hole 13, the tapered portion 41 of the screw 40 deflects the inner wall of the proximal end of the tapered hole 26.
This will push the proximal end only. As a result, the collet 20 is guided by the taper hole 12 and dragged toward the proximal end of the chuck body 1 by an amount corresponding to this deviation e, so that the collet body 21 is radially moved by that amount. Shrink, tool 30
will definitely be retained.

Note that instead of the receiving hole 25, a V-shaped groove may be formed on the outer circumferential surface of the shaft portion 23 of the collet 20, and the collet 20 may be dragged into the chuck body 1 by one or more fluoroset screws. Of course.

A cylindrical rotary cam 5 is provided at the base end of the hollow cylindrical portion 11.
A cam insertion hole 14 into which a 0 is inserted is bored in the radial direction. This rotary cam 50 is used to smoothly perform the detachment operation when the collet 20 is detached from the chuck body 1. That is, the rotary cam 50 is configured such that the shaft portion 23 is inserted into a notch portion 51 formed at an intermediate portion in the axial direction, and the base end surface of the shaft portion 23 faces the notch surface 52. It can be attached to the chuck main body 1 by loosening the fluoroset screw 40.
When a hexagonal wrench (not shown) is inserted into either the hexagonal holes 53, 53 formed at the upper or lower end and the rotary cam 50 is rotated, the end of the notch surface 52 aligns with the base end surface of the shaft portion 23. Since the collet 20 is moved toward the distal end side, the close contact between the chuck body 1 and the collet 20 is released. Therefore, the collet 20 and the tool 30 built therein can be easily removed from the chuck body 1.

Further, a rotation stop ring 54 is attached to the rotation cam 50 to prevent it from rotating unexpectedly. That is, when the rotating cam 50 is rotated by a predetermined amount,
Since the rotation prevention ring 54 comes into contact with the shaft portion 23, further rotation of the rotation cam 50 is prevented. However, the rotation stopper ring 5
4, the collet 20 containing a new tool can be inserted into the correct position within the chuck body 1. That is, if the anti-rotation ring 54 is not provided, the rotating cam 50 may be rotated unexpectedly and the surface opposite to the notch 51 may be located on the distal end side, causing the collet 20 to be located deep inside the chuck body 1. However, if the locking ring 54 is provided, the collet 20 will be removed with the cutout surface 52 slightly inclined with respect to the axis. When inserted, the rotating cam 50 is rotated so that the proximal end surface of the shaft portion 23 is no longer tilted, so that the collet 20 can be inserted and connected to the chuck body 1 correctly.

A coil spring 6 for biasing the collet 20 toward the distal end is inserted into the hole 28 formed at the base end of the shaft portion 23.
0 is attached. That is, as a result of the collet 20 being constantly pushed toward the distal end side by the coil spring 60, the collet 20 is acted upon to expand. Therefore, when inserting a tool into the collet 20, the problem that the collet 20 is closed and the tool cannot be inserted is eliminated. That is, since the collet 20 is always in an expanded state, it has the effect that a tool can be inserted smoothly at any time.

Note that this prevention means is not limited to the coil spring 60 described above, and other spring members such as bamboo shoot springs and disc springs may also be used.
An elastic body such as rubber may also be used.

Modified Example The one shown in FIG. 4 takes a form in which the collet 20 is dragged into the chuck body 1 using bolts and nuts. That is, a through hole 70 is provided in the base end of the hollow cylindrical portion 11 in the radial direction, and a bolt 71 inserted from one end of the through hole 70 through a hole 73 drilled in the shaft portion 23 is inserted into the other end of the through hole 70. It is fastened to a nut 72 attached to the end. The center of the hole 73 is located when the collet 20 is inserted into the chuck body 1.
It is deviated toward the tip side from the center of the through hole 70, and when the bolt 71 and nut 72 are fastened in the through hole 70, the taper parts 71a and 72a formed on the bolt 71 and the nut 72 correspond to the hole 73. Since the proximal inner walls of the tapered holes 74, 74 formed in the portions where the chucks are formed are pressed proximally, the collet 20 is dragged into the chuck body 1 in the same manner as described above.

Effects of the Invention In the case of the chuck according to the present invention described above, the tool can be reliably attached to the chuck body simply by attaching a pressing tool such as a focus screw to the chuck body and the collet.
Therefore, compared to the first and second conventional examples described above, the number of parts can be reduced and the structure can be simplified.

In addition, since threads, gears, etc. are no longer required, there is no risk of looseness due to machining errors, and the tool can be mounted on the chuck body in a centered state, allowing for highly accurate cutting. Become.

Furthermore, since the outer diameter of the tip of the chuck body can be made smaller than that of the first conventional example, there is also the effect that it is possible to machine a stepped deep hole, which was impossible in the first conventional example.

In addition, since an elastic body is used as a means for elastically biasing the proximal end of the collet toward the distal end, the collet is constantly pushed toward the distal end by the elastic body, and as a result, the collet is acted upon to expand. . Therefore, when inserting a tool into the collet, the problem that the collet is closed and the tool cannot be inserted is eliminated. That is,
Since the collet is always in an expanded state, it has the effect that a tool can be inserted smoothly at any time.

Furthermore, since the pressing tool for drawing the collet into the hollow cylindrical portion of the chuck body is of a screw-in type, there is no risk that the pressing tool will loosen even if an impact is applied to the collet in the axial direction. Therefore, the tool is securely held in the collet. Furthermore, since both the pressing tool and the rotary cam operate by rotation, even though different parts are used to pull in and push out the collet, both parts can be operated with the same tool, which not only improves work efficiency, but also
There is nothing wrong with that work.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a chuck according to an embodiment of the present invention, FIG. 2 is a view of FIG. 1 viewed from direction A,
Fig. 3 is an exploded perspective view showing the structure around the proximal end of the collet, Fig. 4 is a longitudinal sectional view showing another embodiment of the present invention, Fig. 5 is a longitudinal sectional view showing a conventional example, and Fig. 6. FIG. 2 is a perspective view showing another conventional example. 1...Chuck body, 11...Hollow cylinder part, 12
... Tapered hole, 13 ... Screw hole, 20 ... Collet, 23 ... Shaft part, 24 ... Taper part, 25 ...
Reception hole, 26...Tapered hole, 30...Tool, 4
0...Full set screw, 41...Tapered part, 6
0...Coil spring.

Claims (1)

[Scope of utility model registration request] a chuck body having a proximal shaft portion connected to the main shaft of a machine tool, a chuck body having a tapered hole formed at the distal end of a hollow cylindrical portion provided on the distal end side with a diameter increasing toward the distal side; and a chuck body inserted into the hollow cylindrical portion; A collet having a taper part corresponding to the taper hole at the distal end and holding a tool inside, a taper hole provided in the radial direction at the base end of the collet, and a taper part corresponding to the taper hole. and penetrates the hollow cylindrical part in the radial direction, and the tapered part is inserted into the tapered hole by screwing,
a screw-in taper presser for pulling the collet into the hollow cylindrical portion; an elastic member for elastically biasing the collet toward the distal end in order to expand the collet;
A portion of the hollow cylindrical portion located on the proximal end side of the collet is provided so as to penetrate the hollow cylindrical portion in the radial direction. A chuck characterized in that the chuck is equipped with a rotating cam such that the proximal end of the collet faces the chuck.