JPS5827046B2 - Arbor for mounting cutting tools - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an arm that is inserted into a spindle of a processing machine and holds a cutting tool such as a shell end mill or a milling cutter.

The conventional cutting tool, ARμ, has a threaded hole in the mounting part formed at the tip, and after inserting the mounting part into the center hole of a milling cutter, etc., a bolt with a flange is screwed into the threaded hole to hold the tool. However, with this type of AR, the bolts must be tightened and loosened manually, which results in poor workability when attaching and detaching the cutting tool.

In addition, it has a disadvantage that it has a complicated structure, poor workability, and difficult centering.

The present invention has been made in view of the above, and it is an object of the present invention to provide an arm that has a simplified structure, improves centering accuracy, and can automatically attach and detach tools.

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

As shown in FIG. 1, the ARμ of the present invention has a mounting portion 2 formed at the tip of a main body 1 to be inserted into the center hole of the cutting tool.
A cavity 3 is provided in this attachment part, and a clamping body 4 is embedded in the cavity 3, so that the outer circumferential surface of the attachment part 2 is pressed against the inner surface of the center hole of the cutting tool to hold the tool.

In the figure, 5 indicates a locking key that is engaged with the joint surface of the cutting tool, and 6 indicates a keyway into which the key of the spindle is fitted.

The mounting portion 2 is formed to have a slightly smaller diameter than the center hole of the cutting tool when cooled, but is pushed outward by a clamping body 4, which will be described in detail later, at room temperature or higher. It is expanded so that its diameter is larger than the diameter of the center hole of the tool.

Therefore, in this state, the outer circumferential surface comes into pressure contact with the inner surface of the center hole of the cutting tool, and the tool is held by the contact resistance at that time.

In order to facilitate elastic deformation of the mounting portion 2, it is desirable that the wall thickness be made as thin as possible without sacrificing strength, or that a plurality of grooves be provided around it.

In addition, in the one shown in FIG. 1, the clamping body 4 is supported by the mounting part 2 via a pin etc., and its tip is exposed from the mounting part 2, but in FIGS. As shown, the entire tightening body may be covered.

That is, in the case shown in FIG. 2, the cover 7 at the tip is formed by drilling a hole from the rear of the main body 1 to provide a cavity 3, and in the case of FIG. After inserting the clamping body 4 into the cavity 3, the cover 5 is attached by welding or the like.

The material of the tightening body 4 is nitinol.
Intermetallic compound of T1Ni, or Cu-Z
A so-called shape memory alloy such as an n-A I series alloy or a Cu-A I-N i series alloy is used, and the hole 3 of the cavity 3 is made so that the mounting portion 2 can be expanded in its original shape by the radial force. It is molded into a cylindrical shape with a diameter larger than the diameter of the cylindrical tube, and is shrunk by cooling, etc., and then inserted into the cavity 3.

When this clamping body 4 is heated to room temperature or higher, it expands in an attempt to return to its original shape, and as a result, the mounting portion 2 is expanded as described above, and its outer peripheral surface is centered at the center of the cutting tool. Press against the inner surface of the hole.

Furthermore, when the clamping body 4 is cooled, it contracts, so that the mounting portion 2 returns to its original state due to the restoring elasticity of the material and is no longer pressed against the tool.

In addition, the tightening body 4 may be one that contracts when heated and expands when cooled, contrary to the above, or one that contracts at room temperature and expands when heated.

The selection is made appropriately according to the usage conditions of ARμ.

Next, the clamping body 4 is cooled and heated by providing a gas introduction hole 8 in the main body 1 and blowing cooling or heating gas around the clamping body from this hole. For,
A plurality of small holes 9, etc., communicating with the gas introduction hole 8 are provided inside this, or a spiral groove 10, etc., communicating with the gas introduction hole 8, etc. are provided on its outer periphery, as shown in FIG.

In this case, it goes without saying that the small hole 7 and the spiral groove 10 can be provided together.

The arm of the present invention is as described above, and by embedding a fastening body made of a shape memory alloy in the attachment part formed at the tip of the main body, and contracting and expanding it by cooling or heating, The outer circumferential surface of the mounting part is pressed against the inner surface of the center hole of the cutting tool, or the pressure is released to mount the tool, making the structure simpler and easier to manufacture than conventional ARμs. In addition, centering becomes easier and its accuracy is improved.

In addition, attachment and detachment of the cutting tool is independent of the temperature of Aμ, that is, Aμ itself tends to become high in temperature due to frictional heat during cutting, and a clamping body expanded by heating will not contract unless this heat is dissipated. , if you forcefully cool it by passing gas through it, the arc
Since this process is performed automatically regardless of the heat level, excellent effects such as significantly improved workability can be obtained.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view showing an arm according to the present invention, and FIG. 2 is a sectional view showing the main parts of another embodiment. 1...Body, 2...Mounting part, 3...Cavity, 4...
・Tightening body, 5... Cover 8... Gas introduction hole, 9.
...Small hole, 10...Spiral groove.

Claims (1)

[Claims] 1. A cavity is provided in the attachment part of the tip of the main body that is inserted into the center hole of the cutting tool, and a shape memory alloy fastening body that deforms with temperature changes is embedded in the cavity. A gas introduction hole leading to the outer periphery is provided in the clamping body, and a small hole or groove is provided in the clamping body, one end of which communicates with the cavity and the other end passing through to the outside, and the gas introduced into this small hole or groove causes the clamping body to A cutting tool mounting arm that expands and contracts by heating or cooling to press the outer circumferential surface of the mounting portion against the inner surface of the center hole of the cutting tool or release it.