JPH11156607A - Cutting tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimize the distribution of pressing and pulling forces and improve the stability of a clamp by providing a spherical-shaped concave part in the upper surface of a throwaway tip and pressing the concave part by a sphere attached to the tip of a presser metal so as to fix the throuwaway tip to the tip seat of a holder. SOLUTION: For setting a thwowaway tip 3 in a tip seat 2 provided in a holder 1, a spherical-shaped concave part 4 is formed in the center of the upper surface of the throwaway tip 3. On the other hand, a sphere 8 having a radius smaller than the curvature radius R of the concave part 4 is fixed by brazing 9 to the tip part of a presser metal 5 fixed by fixing a fastening bolt 6 put through the hole 5a of the presser metal 5 to the holder 1. Then, by locking a support foot 5b provided in the base end side of the presser metal 5 in the holder 1, the pulling of the presser metal 5 to the tip 3 side is prevented, and by bringing the sphere 8 into contact with the spherical surface of the concave part 4, the tip 3 is clamped by the presser metal 5 so as not to be moved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting tool for mounting a throw-away tip on a tip seat of a holder by clamping with a presser foot.

[0002]

2. Description of the Related Art As a technique for clamping a throw-away chip (hereinafter also referred to as a chip for short) mounted on a holder with a presser foot, and pressing the chip against the chip seat bottom surface and the chip seat side surface as shown in FIG. Indexable Tip 3
Is provided with a V-groove 11 on the upper surface thereof, and the slope of the V-groove 11 is pressed by the presser foot 5.

Further, Japanese Patent Application Laid-Open No. 58-59706, Japanese Utility Model Publication No. 51-24626, and Japanese Patent Publication No. Sho 60-50105
There is also a technique as shown in Japanese Patent Publication No. In these methods, the surface of the concave portion provided on the upper surface of the chip is pressed by the convex portion provided on the presser foot.

[0004]

It is desirable that the clamp mechanism of the throw-away tip be capable of freely setting the tip retraction direction at the time of clamping. This is because if the drawing direction is restricted, the use is restricted by the processing form or the chip shape, or the number of corners used for the chip is reduced.

Further, the distribution ratio between the pressing force of the presser by the presser (the pressing force of the chip against the bottom surface of the chip seat) and the pulling force (the pressing force of the chip against the side surface of the chip seat) is determined by using the distribution ratio of the cutting tool. Those that can be set optimally according to the requirements are preferred.

[0006] None of the above-mentioned prior arts satisfy both of these two requirements. That is, in the technique shown in FIG. 7, the retraction direction of the chip 3 is limited to the longitudinal direction of the V-groove 11, so that the use corner of the chip is also limited to two corners.
Further, since the angle of slope of the V groove 11 is constant, the one distribution ratio of the pressing force F ₁ and the retraction force F ₂ is also fixed.

The technique disclosed in Japanese Patent Application Laid-Open No. 58-59706 is also restricted in the direction of retraction. In addition, this technology requires changing the shape of the recess on the top of the chip according to the chip
Since the recess has a shape that breaks the strength balance of each part of the chip, there is also a problem that the chip strength is reduced.

In the technique disclosed in Japanese Utility Model Publication No. 51-26626, the direction of retraction of the chip is arbitrarily determined, but the distribution ratio of the pressing force and the retraction force is changed because the slope of the concave portion is constant. Can not.

In the technique disclosed in Japanese Patent Publication No. Sho 50-501051, the retraction force is applied to the chip by using the elastic restoring force of the preload clamp finger provided on the presser foot, so that the distribution ratio between the pressing force and the retraction force is fixed. Become something.

Accordingly, an object of the present invention is to provide a cutting tool which satisfies the above two requirements by a method which is simple and does not lower the chip strength.

[0011]

In order to solve the above-mentioned problems, in the present invention, a regular spherical concave portion is provided on the upper surface of the throw-away tip, and the concave portion is pressurized by a sphere attached to the tip of the presser foot. The indexable insert was fixed to the tip seat of the holder.

The pressing sphere used has a radius smaller than the radius of the concave portion. This sphere is preferably fixed to the presser foot so that it can be replaced.

[0013]

According to the cutting tool of the present invention, as the amount of deviation of the center of the sphere from the center of the recess increases, the inclination of the surface of the recess in contact with the sphere increases, and the component force generated at the pressing point (the pulling force of this force and Becomes larger. Therefore, the distribution ratio between the pressing force and the retraction force can be changed by increasing or decreasing the above-mentioned bias amount.

Further, since the concave portion has a regular spherical shape, a retracting force can be generated regardless of the direction in which the chip is retracted, and there is no restriction on the retracting direction depending on the tip shape and the shape of the concave portion.

Further, since the concave portion is spherical, the strength balance of the chip is maintained, and a decrease in chip strength can be prevented.

[0016] In addition, when the sphere can be changed, the sphere can be replaced and the presser foot can be reused when the sphere is worn, so that economic waste can be saved.

[0017]

FIG. 1 shows an embodiment of a cutting tool according to the present invention.

FIG. 1 shows a holder. The throw-away tip 3 is set on the tip seat 2 provided on the holder 1. The throw-away tip 3 is provided with a regular spherical recess 4 at the center of the upper surface.

5 is a presser foot for tip clamp, and 6 is
It is a tightening bolt penetrated through the hole 5a of the presser foot. The tightening bolt 6 is screwed into the holder 1. The tightening bolt 6 is provided with a snap ring 7 to prevent parts from being removed from the presser foot 5 in order to improve the handleability of parts. However, this is not an essential configuration.

The presser foot 5 locks the support foot 5b provided on the base end side to the holder 1 so as not to be pulled toward the chip 3.

The tip of the presser foot 5 has a radius 4
Is attached to the spherical surface of the concave portion 4 and the tip 3
Clamp. The sphere 8 is preferably made of a hardly wearable material, for example, a cemented carbide or steel. Here, the sphere 8 is brazed and attached to a ball seat 5c provided corresponding to the presser foot 5 (9 is a brazing portion), but as shown in FIG. It is also possible to make the diameter of the part smaller than the maximum diameter and press-fit the sphere into the ball seat 5c for mounting. Both mounting structures allow replacement of worn spheres, thereby reducing repair costs.

FIG. 2 shows an example of the planar shape of the throw-away tip 3. The example shapes are triangular, square,
Although there are four types, a rhombus and a circle, in the present invention, since there is no restriction on the retraction direction, chips having other shapes can be stably clamped.

FIG. 3 shows an example in which the distribution ratio between the pressing force and the retraction force is changed. FIG. 3A shows that the amount of deviation E of the sphere 8 from the center of the recess 4 to the base end side of the presser foot is increased. the proportion of retraction force F _2, which accounts in the force is large. FIG. 3 (b) is to reduce the aforementioned deviation amount E, since the inclination angle of the pressure points is small, the proportion of the pressing force F ₁ occupied in the clamping force increases.

Of these, the force distribution shown in FIG. 3A is suitable for continuous cutting in which the cutting force is constant, while the force distribution shown in FIG. Suitable for intermittent cutting, which easily rises from the bottom of the insert seat.

If the above-mentioned deviation amount E can be adjusted, the same tool can cope with both continuous cutting and intermittent cutting. As a method of adjusting the amount of deviation E, a method of replacing the presser foot 5 with a different length, a method of providing a play (gap) between the tightening bolt 6 and the hole 5a in FIG. A method is conceivable in which a shim, a wedge, an adjusting screw, or the like is provided to separate the presser foot 5 from the surface 1a and the position of the presser foot 5 is shifted in the chip retraction direction.

FIGS. 4 and 5 show a cutting tool and a cutting tool to which the present invention is applied. A in the figure is a work material. The clamping mechanism of FIG. 7 has restrictions on the retraction direction and is not suitable for the tool for drawing and cutting of FIG. 5 (if this mechanism is used, the dimension from the cutting edge to the tip of the holder becomes longer and becomes an unrealistic tool). However, the present invention can be applied to the tool shown in FIG. 5 without any problem.

FIG. 6 shows an example in which the present invention is applied to an end mill. In this end mill, two tip seats 2 are provided point-symmetrically on the outer periphery of the tip end of a holder 1, and a throw-away tip 3 having a triangular basic shape is attached thereto using the clamp structure of FIG. Three corners can be used as cutting edges.

[0028]

As described above, according to the cutting tool of the present invention, a regular spherical concave portion is provided on the upper surface of the insert, and the concave portion is pressed by a sphere attached to the presser foot to clamp the insert. In addition, the distribution of the drawing force and the drawing direction of the chip can be optimally determined according to the use of the tool and the shape of the chip to be used, and the stability of the clamp can be increased with a simple structure, and the use restriction can be eliminated.

Further, since the concave portion is spherical, the strength of the chip does not decrease and the life of the chip is extended.

Further, the one in which the sphere is replaceable has the advantage that the presser foot can be easily manufactured and the repair can be performed economically.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of a tool according to an embodiment.

FIGS. 2A to 2D are views showing an example of a planar shape of a throw-away tip.

FIG. 3A is an enlarged cross-sectional view showing a state in which the distribution of the retraction force is increased. FIG. 3B is an enlarged cross-sectional view showing a state in which the distribution of the pressing force is increased.

FIG. 4 is a diagram showing an example of application to a drawing cutting tool;

FIG. 5 is a diagram showing an example of application to a press cutting tool.

6A is a cross-sectional view showing an example of application to an end mill. FIG. 6B is a front view of the same end mill. FIG.

FIG. 7A is a plan view of a tip clamp mechanism used in a conventional tool. FIG. 7B is a cross-sectional view of the same clamp mechanism.

[Explanation of symbols]

1 holder 2 tip seat 2a tip seat bottom 2b tip seat side 3 throw-away tip 4 recess 5 presser foot 6 fastening bolt 7 snap ring 8 spheres 9 brazed portion F ₁ pressing force F ₂ pull force

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takeshi Nakagawa 7 Teiho-machi, Teiho-cho, Toyota City Inside Toyota Motor Corporation Teiho Plant (72) Inventor Yoshihiro Sato 7 Teiho-machi, Teiho-cho Toyota City Toyota Motor Corporation Teiho Plant Inside

Claims (3)

[Claims] 1. A cutting tool in which a regular spherical concave portion is provided on the upper surface of a throw-away tip, and the concave portion is pressed by a sphere attached to the tip of a presser foot to fix the throw-away tip to a tip seat of a holder. 2. The cutting tool according to claim 1, wherein the sphere is fixed so as to be replaceable with a presser foot. 3. The method according to claim 1, wherein the center of the sphere is biased toward the base end of the presser foot from the center of the recess so that the pressing force against the bottom surface of the tip seat and the pressing force against the side surface of the chip seat are applied to the throw-away tip. Item 3. The cutting tool according to Item 1 or 2.