JPH0727046Y2 - Chuck - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chuck for holding a tool such as a drill.

[0002]

2. Description of the Related Art As a chuck of this kind, a chuck body, a collet fitted to the chuck body, a tightening nut screwed to the chuck body, and a collet fitted in the tightening nut. There is a nose ring that is press-contacted, and a plurality of balls are fitted into the annular hole formed between the fitting surfaces of the tightening nut and the nose ring, through the ball insertion holes of the tightening nut. Then, with this chuck,
When inserting the shank part of a tool such as a drill into the collet and tightening and turning the tightening nut, the tightening nut moves to the chuck body side and is connected to this tightening nut through the ball in the annular hole. The nose ring also moves to the chuck body side while allowing the nut to rotate freely, and the diameter of the collet tip side is reduced by this nose ring, and at the same time, the collet is reduced in diameter by being pushed into the chuck body. Thus, the shank portion of the tool is firmly gripped.

By the way, generally, the ball insertion hole for inserting a plurality of balls into the annular hole is conventionally closed by screwing a closing bolt or pressing a closing plug into the ball insertion hole. However, in the case of screwing with a closing bolt, the thickness of the tightening nut must be increased, which makes the weight heavy, making it unsuitable for high-speed precision rotation. Although the thickness of the tightening nut can be reduced, the plug is easily removed and there is a risk that the ball may come off the insertion hole.

As a means for solving such problems,
There is a chuck described in Japanese Utility Model Publication No. 4-35050. This is because a cover member that can close the ball insertion hole is fitted on the outer peripheral surface of the tightening nut. This cover member prevents the ball from coming off, and the thickness of the tightening nut is made as thin as possible. it can.

[0005]

In the chuck described in the above publication, the cover member is externally fitted and fixed to the tightening nut so as to close the ball insertion hole. Since the surface is provided with a concave groove portion for rotating the nut, the cover member is fitted on the outer peripheral surface of the nut at a position not covered by the concave groove portion for rotating operation,
Need to stick. That is, since the ball insertion hole is usually provided on the tip side of the tightening nut, the rotary operation concave groove portion is provided on the outer peripheral surface of the tightening nut on the rear end side. It is necessary to externally fit and fix the outer peripheral surface, but in order to externally fit and fix the cover member to the outer peripheral surface on one side of the tightening nut, the rear end portion of the cover member is fixed to the outer peripheral surface of the nut by caulking means or the like. Since it has to be done, it takes a lot of work to fix it, and
It is necessary to form the outer peripheral surface of the tightening nut into a specific shape, for example, by forming a stepped portion on the outer peripheral surface of the nut, with which the end of the cover member can be locked. Particularly, since the rotary operation concave groove portion needs to be formed to have a constant length (length in the length direction of the tightening nut), when the length of the tightening nut is short, Since the fitting width of the cover member becomes narrower, the work of attaching the cover member becomes more difficult.

As described above, in the conventional cover member for preventing the balls from coming out of the ball insertion hole, the work of fixing the tightening nut on the outer peripheral surface is very troublesome, and the nut outer surface has a specific shape. Since it has to be formed, it is difficult to manufacture and attach, and the cost is high.

In view of the above problems, an object of the present invention is to provide a chuck which has a simple structure, is easy to manufacture, and can be manufactured at low cost.

[0008]

In order to achieve the above object, the chuck according to the present invention has a pin nut insertion hole 17 which penetrates a ball insertion hole 15 in a crossing direction of a tightening nut 8.
Is provided, and the locking pin 18 is inserted thereinto, and the padding 20 is loaded in the ball insertion hole 15 so as to be locked by the locking pin 18.

An adhesive is preferable as the filling material 20. Further, the pin insertion hole 17 is provided with the tightening nut 8
Preferably, it is drilled in the axial direction.

[0010]

EXAMPLES Examples will be described with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a chuck body detachably attached to a spindle of a machine tool, and a screw portion 2 is provided on an outer peripheral surface at a tip portion thereof.
Is formed, and a tapered surface 3 with a deep constriction is formed on the inner peripheral surface. Reference numeral 4 denotes a collet fitted into the chuck main body 1, and a plurality of split grooves 4a are alternately formed from both front and rear ends thereof, and a tapered taper surface 5 is formed at the tip of the collet 4. Further, a taper surface 6 is formed on the rear end side, the taper surface 6 forming an inverse taper to the front end side taper surface 5,
A locking circumferential groove 7 is formed in the middle of the two tapered surfaces 5, 6.

Reference numeral 8 is a tightening nut that is screwed to the chuck body 1. A threaded portion 9 that engages with the threaded portion 2 of the chuck body 1 is formed on the inner peripheral surface on the rear end side, and a rotating operation is performed on the outer peripheral surface. Concave grooves 8a for use are formed at predetermined intervals in the circumferential direction. Reference numeral 10 denotes a nose ring fitted into the tip of the tightening nut 8 and pressed against the collet 4, and a tapered surface 11 fitted to the tip side tapered surface 5 of the collet 4 is formed on the inner peripheral surface of the tip. A locking projection 12 that can be locked in the locking circumferential groove 7 of the collet 4 is formed on the inner peripheral surface of the rear end portion.

As shown in FIG. 3, the tightening nut 8 is provided between the fitting surfaces of the tightening nut 8 and the nose ring 10.
Is formed with a semi-circular groove 13a on the side and a semi-circular groove 13b on the nose ring 10 side, and a ball for inserting the ball 14 into the annular hole 13 is formed in the tightening nut 8. An insertion hole 15 is provided. Then, the tightening nut 8 and the nose ring 10 are rotatably connected to each other by the plurality of balls 14 fitted into the annular hole 13 through the ball insertion hole 15 and are immovable in the axial direction. . The ball insertion hole 15 is
The hole has a circular cross section larger than the diameter of the ball 14, and a step portion 16 is formed at the peripheral edge of the bottom of the insertion hole 15.

As shown in FIGS. 1 and 2, the tightening nut 8 is provided with a pin insertion hole 17 penetrating the ball insertion hole 15 in the transverse direction thereof in the axial direction of the tightening nut 8. The locking pin 18 is inserted into the pin insertion hole 17. When inserting the locking pin 18, as shown in FIG.
As shown in FIG. 5, a preliminary hole 19 having a relatively large diameter is bored from the rear end face side of the tightening nut 8 on the front coaxial line of the pin insertion hole 17 to be bored, and the front side of the preliminary hole 19 is bored. The pin insertion hole 17 is bored so as not to penetrate the tip end surface of the tightening nut 8. Then, the ball 14 is inserted into the annular hole 13.
In the state in which is inserted, a locking pin 18 having a diameter slightly smaller than the pin insertion hole 17 and having substantially the same length as that is inserted into the pin insertion hole 17. The locking pin 18 is preferably a metal rod-shaped member such as a piano wire, but a rod-shaped member made of hard plastic can also be used.

After the locking pin 18 is inserted into the pin insertion hole 17 as described above, the padding 20 is loaded into the ball insertion hole 15 and the preliminary hole 19, respectively, and the locking pin 18 is put in place. Fix it. The padding 20 is made of an adhesive, and is preferably made of a thermosetting resin, especially an epoxy resin. In this case, the adhesive filling 20
As shown in FIG. 1 and FIG. 3, the state in which the bottom of the ball insertion hole 15 is filled so as to reach the lower side of the locking pin 18 and the locking pin 18 is embedded in the padding 20. And As a result, the padding 20 is locked by the locking pin 18 and fixed in the ball insertion hole 15. Also,
As the padding 20, a block made of metal or plastic having a shape that fits properly into the ball insertion hole 15 is used, and a locking hole into which the locking pin 18 is inserted is provided in this block, and the pin 18 is provided in this locking hole. Alternatively, the padding 20 of the block may be locked by the pin 18 and fixed in the ball insertion hole 15 by inserting.

In using the chuck having the above-mentioned structure, as shown in FIG. 1, a tool T such as a drill is inserted into the collet 4 and the tightening nut 8 is provided on the outer peripheral surface of the collet 4. By locking an appropriate rotary operation tool in the groove 8a and rotating in the tightening direction, the tightening nut 8
Moves to the chuck body 1 side together with the nose ring 10 rotatably connected via the ball 14, and accordingly, the tapered surface 11 of the nose ring 10 press-contacts the tip side tapered surface 5 of the collet 4. The rear end side taper surface 6 of the collet 4 is in pressure contact with the taper surface 3 of the chuck body 1, and the collet 4 is reduced in diameter by the press contact action between the taper surface 3 and the taper surface 6 and between the taper surface 11 and the taper surface 5. Tool T
Grab and fix.

In this way, the spindle of the machine tool is rotated while the tool T is gripped and fixed by the chuck, and the tool T is rotated through the chuck. The ball 14 on the ball insertion hole 15 side is rotated by the chuck rotating at high speed. Even if a considerable centrifugal force is applied to the ball 14, the padding 20 loaded in the ball insertion hole 15 causes the balls 14 to come out of the ball insertion hole 15.
Is prevented from exiting.

In this case, even if the pressing force due to the centrifugal force of the balls 14 acts strongly on the bottom surface of the pad 20 in the state shown in FIG. 1, the pad 20 is locked by the locking pin 18. Since it is fixed, the ball insertion hole 15
There is no danger of breaking away from and popping out. Further, since the padding 20 is made of an adhesive, it is closely fixed to the inner wall of the ball insertion hole 15 when it is filled in the ball insertion hole 15 and is integrally coupled with the locking pin 18 to form a ball insertion hole. It is securely fixed in 15.

In the embodiment described above, when the pin insertion hole 17 for inserting the locking pin 18 is formed,
Although the preliminary hole 19 is drilled on the front side of the pin insertion hole 17, such a preliminary hole 19 may be omitted and the pin insertion hole 17 may be directly drilled in the tightening nut 8.

[0019]

According to the present invention, the filling in the ball insertion hole is locked and fixed by the locking pin inserted into the pin insertion hole of the tightening nut. Therefore, even when a considerable centrifugal force acts on the ball located in the ball insertion hole during high speed rotation of the chuck, there is no possibility that the padding will fly out from the ball insertion hole. In particular, according to the first aspect of the present invention, since the padding to be loaded in the ball insertion hole is locked by the pin provided so as to cross the ball insertion hole, the ball is prevented from coming out of the conventional cover member. Compared with the means, the structure is extremely simple, the manufacture is easy, and the cost can be reduced.

When the filling is made of an adhesive as in claim 2, the filling into the ball insertion hole is facilitated, and the filling filled in the ball insertion hole is integrally coupled with the locking pin. At the same time, it can be tightly fixed to the inner wall of the ball insertion hole, and is reliably fixed in the ball insertion hole.

When the pin insertion hole is bored in the axial direction of the tightening nut as in the third aspect, the work of boring the pin insertion hole becomes easy.

[Brief description of drawings]

FIG. 1 is a half sectional view of a chuck showing an embodiment of the present invention.

FIG. 2 is a partial plan view seen from an arrow A in FIG.

FIG. 3 is a partial front view of the chuck shown in FIG.

[Explanation of symbols]

 1 Chuck body 3 Tapered surface 4 Collet 5 Tapered surface 6 Tapered surface 8 Tightening nut 10 Nose ring 11 Tapered surface 13 Annular hole 14 Ball 15 Ball insertion hole 17 Pin insertion hole 18 Locking pin 20 Filling

Claims (3)

[Scope of utility model registration request] 1. A chuck body, a collet fitted in the chuck body, a tightening nut screwed in the chuck body, and fitted in the tightening nut to be pressed against the collet. A nose ring, and an annular hole is formed between the fitting surfaces of the tightening nut and the nose ring, and a plurality of annular holes are inserted into the annular hole through ball insertion holes provided in the tightening nut. In a chuck having a ball inserted therein, the tightening nut is provided with a pin insertion hole penetrating the ball insertion hole in a transverse direction thereof, and a locking pin is inserted into the pin insertion hole, and at the same time, the ball insertion hole is inserted into the ball insertion hole. A chuck in which packing is loaded so as to be locked by the locking pin. 2. The chuck according to claim 1, wherein the filling is made of an adhesive. 3. The chuck according to claim 1, wherein the pin insertion hole is formed in an axial direction of the tightening nut.