JPH028644Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a tool holder for holding various cutting tools on the main shaft of a machine tool.

BACKGROUND TECHNOLOGY Conventionally, this type of tool holder includes a holder body in which a cylindrical part having a tapered hole is connected to the tip of a shank part, a taper collet fitted in the tapered hole, and a screw provided on the outer periphery of the cylindrical part. a tightening nut that is screwed into the cylindrical portion; and a retraction member that is fitted into an engagement hole that is provided to penetrate in the diametrical direction of the cylindrical portion so as to be movable only in the axial direction, A tool holder is known in which the tool holder is rotatably connected to a member and the taper collet is connected to the retracting member (see, for example, Japanese Utility Model Application Publication No. 183104/1983).

The above-described tool holder converts the rotational force of the tightening nut into axial force via the retracting member, and the retracting member draws the taper collet into the tapered hole of the holder body to obtain gripping force for the tool. Compared to a type of tool holder that is pushed into a tapered hole to generate gripping force, the taper collet moves smoothly in contact with the taper hole, and no compressive force is applied to the collet, so there is no risk of the collet buckling. There are advantages such as

Problem to be Solved by the Invention However, in the above tool holder, when the rotational force of the tightening nut is converted into axial force via the retracting member, sliding wear occurs between the tightening nut and the retracting member. This abrasion causes looseness, which tends to reduce the holding accuracy of the tool.

The present invention aims to solve these problems and provide a tool holder that can maintain tool holding accuracy over a long period of time.

Means for Solving the Problems In order to achieve the above object, in the present invention, outer surfaces of both ends of the retracting member are formed in an arc shape, and the outer circumferential surface of the cylindrical portion of the holder main body is formed on the outer surface. A groove continuous to the groove is provided, and an annular groove opposite to the groove is provided on the inner periphery of the tightening nut, and an annular groove is formed between the annular groove and the groove and the outer circumferential surface of the cylindrical portion. A plurality of balls are rotatably fitted in the annular passage, and the tightening nut is rotatably connected to the retracting member via the balls.

Effect With the above configuration, only the ball located between the annular groove of the tightening nut and the groove of the retracting member acts as an intermediary when converting the rotational force of the tightening nut into the axial force of the retracting member. to do. On the other hand, the ball located between the annular groove and the outer peripheral surface of the cylindrical portion of the holder main body is kept in an idle state.

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 1 shows the tool holder according to the present invention with the main parts cut away.

The holder main body 11 includes a cylindrical portion 14 having a tapered hole 15 at the tip of a shank portion 12 through a large diameter portion 13.
are connected to each other, a threaded portion 16 is provided on the outer peripheral surface of the cylindrical portion 14, and two substantially rectangular engagement holes 17, which are elongated in the axial direction, are provided at the base end portion of the cylindrical portion 14 rearward from the threaded portion 16. 17 are formed so as to penetrate through the cylindrical portion 14 in the diametrical direction and to be aligned in phase by 180 degrees in the circumferential direction. (See Figure 4).

Taper collet 20 that grips cutting tool 19
As clearly shown in FIG. 5, it has a tapered cylindrical portion 21 that matches and fits into the tapered hole 15, and a cylindrical portion 23 that is connected to the rear end via a small diameter portion 22. There is. Three grooves 24 are provided in the tapered cylindrical portion 21, and each groove 24 extends in the axial direction from the tip of the tapered cylindrical portion 21 and opens into an opening 2 provided in the small diameter portion 22.
It has reached 5. Further, the rear end protrusion 26 of the cylindrical portion 23 has a pair of diametrically opposed flanges 2.
7 and 27 are arranged in series (see Fig. 6). One side of both flanges 27 is cut into a flat surface 28 extending parallel to each other to the protrusion 26, and the other side is cut into a slope 29 parallel to each other.

As shown in FIGS. 1 to 3, the taper collet 20 configured as described above has the cylindrical portion 23 inserted deep inside the cylindrical portion 14 of the holder main body 11, and the tapered cylindrical portion 21 is brought into close contact with the taper hole 15. It is fitted and attached, and the rear end protrusion 26 is attached to both flanges 27, 27.
It is connected to a retracting member 30 which will be described later.

The retracting member 30 has a rectangular outline as shown in FIG.
1 is formed in an arc shape, and a groove 32 having a semicircular cross section is provided on the outer surface 31. Also,
The retracting member 30 has an elongated hole 33 into which the rear end protrusion 26 of the taper collet 20 and both flanges 27, 27 fit.
, and both flanges 2 are provided on the opposing inner walls of the elongated hole 33.
Recessed portions 34, 34 are provided in which the portions 7, 27 engage.

The retracting member 30 is fitted into the engagement holes 17, 17 provided at the proximal end of the cylindrical portion 14 of the holder main body 11 so as to be movable only in the axial direction, and in this fitted state, the recessed grooves 32 on both outer sides 31, 31, 32 is continuous with the outer circumferential surface 14a of the cylindrical portion 14, and its groove bottom is located on the same circle as the outer circumferential surface 14a, and the rear end protrusion 26 of the taper collet 20 inserted into the cylindrical portion 14 and both flanges 27, 27 are drawn into the member 3.
After fitting into the elongated hole 33 of 0, it is rotated approximately 90 degrees and both flanges 27, 27 are engaged with the recesses 34, 34, as shown in FIGS. 2 and 3. , the taper collet 20 and the retracting member 30 are connected in the axial direction, and the two can move together in the axial direction. A pin 35 shown in FIG. 3 is fixed and protruded in the elongated hole 33 of the retracting member 30, and functions as a stopper that restricts rotational displacement of both flanges 27, 27 fitted in the elongated hole 33.

The tightening nut 36 is screwed into the threaded portion 16 of the cylindrical portion 14 and is connected to the cylindrical portion 3 connected to the rear end thereof.
7 is fitted onto the large diameter portion 13 of the holder main body 11. An annular groove 38 having a semicircular cross section and forming a passage having a circular cross section is provided on the inner circumferential surface of the tightening nut 36, and is located opposite to the groove 32 of the retracting member 30. Also forms a passage with the outer circumferential surface 14a of the cylindrical portion 14, which is continuous with the circular cross-sectional passage. Thus, as described above, the annular groove 38, the groove 32 of the retracting member 30, and the cylindrical portion 14
By inserting a large number of balls 40 into an annular passage formed between the outer circumferential surface 14a of Only rotationally connected.

In the figure, 41 is a set screw that closes the ball insertion hole 39, and 42 is a sealing.

In the above configuration, when the tightening nut 36 is rotated in the tightening direction, the rotational force is converted into an axial force via the ball 40, and the retracting member 30 is moved axially rearward. In conjunction with the retracting member 30, the taper collet 20 is smoothly retracted into the taper hole 15, and due to the wedge action with the taper hole 15, the diameter is gradually reduced to grip the cutting tool. At this time, since a tensile force is applied to the taper collet 20 and no compressive force is applied to the taper collet 20, there is no possibility that the collet 20 will buckle. Conversely, when the tightening nut 36 is rotated in the loosening direction, the retracting force on the taper collet 20 is released and the taper collet 20 is pushed out of the taper hole 15 and expands in diameter, making it possible to easily pull out the cutting tool 19 from the collet 20. . Note that when the collet 20 is pushed out, a compressive force acts on the collet 20, but this compressive force acts while releasing the gripping force due to the wedge action of the tapered hole 15, so that no buckling problem occurs.

On the other hand, the annular groove 38 of the tightening nut 36, the groove 32 of the retracting member 30, and the outer circumferential surface 14 of the cylindrical portion 14
A large number of balls 40 held in an annular passage formed between
and the annular groove 3 of the tightening nut 36.
8 and the groove 32 of the retracting member 30 acts to convert the rotational force of the tightening nut 40 into the axial force of the retracting member 30. The ball 40 located between the outer circumferential surface 14 of the cylindrical portion 14 is kept in a loose state. Therefore, a plurality of balls 40 are used alternately in portions to convert the rotational force of the tightening nut 36 into an axial force, thereby increasing the service life of the balls 40.

Effects of the Invention As explained above, according to the tool holder of the present invention, when the retractable member fitted to the base end of the cylindrical portion of the holder main body is moved in the axial direction by the rotational force of the tightening nut, the annular recess of the tightening nut is moved. Since only the balls located between the groove and the concave groove of the retracting member are used to convert the rotational force of the tightening nut into axial force, the remaining balls are kept in a state of play. , a large number of balls are used alternately, part by part, to convert the rotational force of the tightening nut into axial force, which increases the service life of the balls and maintains the holding accuracy of the tool for a long time. can be maintained over a period of time.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway side view of a tool holder according to an embodiment of the present invention, Fig. 2 is a sectional view taken along line 2-2 in Fig. 1, and Fig. 3 is a sectional view taken along line 3-3 in Fig. 1. FIG. 4 is a perspective view of the main part of the holder main body, and FIG.
FIG. 6 is a perspective view showing the taper collet retracting member, and FIG. 6 is a sectional view showing the rear end protrusion and the flange of the taper collet. 11...Holder body, 12...Shank part, 1
4...Cylinder part, 15...Tapered hole, 16...Threaded part, 17...Engagement hole, 20...Tapered collet,
26... Rear end protrusion, 27... Flange, 30... Retractable member, 32... Concave groove, 33... Elongated hole, 34...
... recessed part, 36 ... tightening nut, 38 ... annular groove, 40 ... ball.

Claims (1)

[Claims for Utility Model Registration] A holder body in which a cylindrical part having a tapered hole is connected to the tip of the shank part, a taper collet fitted in the taper hole, and a threaded part provided on the outer periphery of the cylindrical part. a retractable member fitted into an engagement hole provided in the cylindrical portion so as to be movable only in the axial direction, and the retractable member is rotated by the retractor. and the taper collet is connected to the retracting member, wherein the outer surface of both ends of the retracting member is formed in an arc shape, and the outer surface of the holder main body is connected to the retracting member. A groove that is continuous with the outer circumferential surface of the cylindrical portion is provided, and an annular groove that is opposite to the groove is provided on the inner periphery of the tightening nut, and the annular groove, the groove, and the outer circumferential surface of the cylindrical portion are connected to each other. A tool holder characterized in that a plurality of balls are rotatably fitted in an annular passage formed between the tool holders, and the tightening nut is rotatably connected to the retracting member via the balls.