JPS5827045B2 - cutting tool holder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a holder for holding cutting tools such as drills, reamers, and taps.

Conventional holders of this type have a split collet with a tapered outer periphery interposed between the tapered center hole of the holder body and the shank of the cutting tool inserted into it, and this collet is screwed onto the tip of the body. Tighten and contract with the engaged nut,
A method of holding the tool is adopted.

However, since the above-mentioned holder requires manual attachment and detachment of the cutting tool, the workability is poor, and large holders require a large force to tighten and remove the nuts.

In addition, since a split collet is essential as a component of the holder, the number of parts increases, which increases costs.In addition, misalignment between the center hole of the collet and the center hole of the main body inevitably occurs, which reduces machining accuracy. is having a negative impact on

The present invention has been made in view of the above, and its purpose is to provide a holder in which a cutting tool can be automatically attached and detached, and a split collet is not required.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the holder of the present invention has a center hole 2 at the tip of a main body 1 into which a shank S of a cutting tool is inserted, and a cavity 3 whose axis coincides with the central axis of the main body 1. It has a structure in which a grip part 4 and a support part 5 surrounding the grip part are formed, and a tightening body 6 is inserted into the cavity 3.

The gripping part 4 deforms when pushed by a tightening body 6, which will be described in detail later, and grips the shank S of the cutting tool inserted directly into the center hole 2 of the main body. It is desirable to keep the wall thickness as thin as possible without compromising rigidity.

Note that this gripping portion 5 has a plurality of split grooves (not shown) formed therein similar to those formed in conventional split collets, and the gripping portion thus formed is contracted by the tightening body 6. The shank S may also be gripped by holding the shank S.

The support part 5 engages with the clamping body 4 to support it, covers and protects the clamping body 6, and in some cases,
The clamping body serves to receive and stop the pressure when the gripping portion 4 is compressed.

As shown in FIG.
If a cylindrical ring is attached and formed through a holder etc., processing of the holder becomes easy.

However, if the tightening force of the shank is small, the support section 5 can be omitted by engaging and supporting the clamping body 6 with the grip section 4.

Therefore, the support portion 4 is not an essential requirement of the present invention.

Next, the tightening body 6 is made of nitinol (n1tin) as a material.
T1Ni intermetallic compound called ol) or C
So-called shape memory alloys such as u-Zn-Al1-based or Cu-Al-Ni-based alloys are used, and these metals are formed into a cylindrical shape large enough to compress the gripping part 4 in their original shape, and then gripped. The hollow 3 is filled by stretching the part 4 until it has a decompressed diameter and fitting it into the grip part 4.

When the tightening body 6 reaches room temperature or is heated to a higher temperature, it tries to return to its original shape and contracts, compressing the gripping part 4.

On the other hand, when it is cooled to below room temperature, it expands due to the reversible shape memory effect, returns to the stretched state, and releases the compression of the grip part 4.

Here, the tightening body 8 may be one that contracts only when heated and becomes stretched at room temperature or lower, and further, contrary to the above, one that contracts when cooled. You can also use a trowel.

The selection is made as appropriate depending on the usage conditions of the holder.

Further, the heating and cooling of the clamping body 8 is achieved by providing a gas introduction hole 8 in the main body 1 that passes from the side to the top of the clamping body 6, and through this hole heating or cooling gas is introduced around the clamping body 6. This is done by feeding the gas, but in order to hasten the reaction of the clamping body 6 to the gas,
Inside this, a plurality of small holes 9 communicating with the gas introduction hole 8 of the main body are provided at appropriate intervals so that the gas sent in enters into the small holes 9.

In addition, in order to speed up the reaction of the tightening body 6, this tightening body 6
may be formed of a plurality of rings as shown in FIG. 2, so that the gas guided through the small hole 9 enters the gap between each ring.Furthermore, as shown in FIG. A spirally wound pipe may be used around the attached body 6, and gas may be passed through the pipe.

As described above, the holder of the present invention attaches and detaches a cutting tool in a completely different manner from the conventional holder, and has the excellent effects and many advantages listed below.

(1) The clamping body is made of a shape memory alloy, and its properties are used to compress and release the grip, making it possible to attach and detach the cutting tool simply by heating or cooling the clamping body. becomes.

Therefore, work efficiency is significantly improved and labor is reduced.

(2) Since the cutting tool is gripped by the grip formed on the main body, a split collet is not required.

In addition, since the conventionally required tightening ring is omitted, manufacturing becomes easier and costs are reduced.

(3) Since the shank of the cutting tool is directly inserted into the center hole of the main body, centering is facilitated.

Furthermore, the accuracy of the propelling screw of the tightening ring previously affected the centering accuracy, but this is eliminated.

(4) Since the gripping portion is integrated with the main body, the rigidity of the holder is increased and durability is improved, and the gripping force is also increased, and this also allows the holder to be made smaller.

(5) Since the gripping portion is heated and cooled by passing gas through a small hole provided in the gripping portion, there is no problem in practical use.

In other words, cutting tool holders often reach high temperatures due to the transmission of frictional heat during cutting, and therefore, the clamping body used at this time is required to shrink when heated in order to eliminate a drop in clamping force. Ru.

However, if this clamping body is used, it will take a considerable amount of time before the diameter expands due to natural cooling, which will reduce the operating rate of the machine, making it impractical, but the forced cooling method using gas described above can be used. For example, since the introduced heating gas and cooling gas can be easily switched, the clamping body can be expanded quickly even if the holder is at a high temperature.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a holder of the present invention, and FIGS. 2 and 3 are sectional views showing essential parts of other embodiments. 1... Body, 2... Center hole, 3...
...Cavity, 4...Gripping part, 5...Supporting part, 6...Tightening body, 8...Gas introduction hole, 9... ...Small hole.

Claims (1)

[Claims] 1. A main body integrally provided with a central hole into which the shank of a cutting tool is inserted and a gripping part that can be elastically deformed or contracted at the tip, and the gripping part is made of a shape memory alloy that deforms with temperature changes. A gas introduction hole is provided in the main body, one end of which is open to the outer circumferential surface, and the other end of which is open to the upper surface of the tightening body, On the other hand, the clamping body is provided with a large number of small holes, one end of which communicates with the gas introduction hole and the other end of which exits to the lower surface of the clamping body, all around the circumference or continuously in a spiral shape. A holder for a cutting tool, wherein the clamping body is heated or cooled by gas introduced into the small hole to contract and expand, thereby compressing and releasing the gripping portion.