JPH0911016A - Pin milling cutter - Google Patents

Abstract

PURPOSE: To perform easy and speedy mounting work of a pin milling cutter on a machine tool by improving a key groove section of the pin milling cutter which is positioned by key fitting and has an internal shape. CONSTITUTION: In key grooves which are equally arranged on outer periphery of a cutter main body 1, a screw hole 20 is drilled almost vertically on a side wall 19 which is positioned in a rear section in the direction of rotation, and a ball plunger 21 which is a spring part and a set screw 22 which positions and fixes the ball plunger 21 are embedded. A tip of the ball plunger 21 protrudes to such an extent that it presses a side of a key 6. Since the key groove 8 comes into contact with the key 6 at all times in a front section in the direction of rotation, it is unnecessary to keep a clearance between the key 6 and the key groove 8 with high precision when compared with the conventional method, and the key fitting is done easily and speedily.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a key groove portion of an internal type pin milling cutter used for machining a crankshaft pin.

[0002]

2. Description of the Related Art The key groove of a pin milling cutter, which is key-fitted to the end of a spindle of a machine tool, serves as a standard for determining the assembling accuracy of a cutting edge, in addition to the function of transmitting a rotary motion. Therefore, it is required that the accuracy of the indexing position in the circumferential direction of the key groove, which is normally provided in the cutter body evenly in four places, and the fitting accuracy of the key groove and the key are high. .

[0003]

The fitting accuracy of the key and the key groove is conventionally set to have a clearance of about 10 to 20 μm. However, since the pin milling cutter has a large outer diameter and is heavy and has a high fitting accuracy as described above, it is difficult to operate when attaching to and detaching from the machine tool, which causes a decrease in workability. There is. Further, if the cutter is inserted in a slightly inclined state, the fitting portion is bitten and the mounting work is not progressed. Attempting to eliminate this by hitting it with a hammer etc. may result in wear or deformation of the keyway.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a key groove is provided on the outer periphery of a cutter body having a hollow disk shape, which is provided at a spindle end of a machine tool. In a pin milling cutter adapted to be rotationally driven by fitting and fixing a key and the key groove, a coil spring, a disc spring, and a leaf spring are provided on the side wall of the key groove located rearward in the rotational direction of the cutter. When a spring component such as the above is incorporated and one end thereof is projected and the key is fitted, a pressing force is exerted by the spring component in the direction of expanding the clearance between the side surface of the key facing the side wall of the key groove. It is characterized in that it is configured to operate. In addition, a ball plunger is incorporated as a spring component.

[0005]

When the key is pressed by the spring component, the clearance between the key and the key groove is expanded behind the key groove in the cutter rotation direction, that is, on the side where the spring component is incorporated. As a result, the key groove always comes into contact with the key at the side wall on the opposite side, that is, at the front position in the cutter rotation direction, and the rotational drive is transmitted. Since the cutter is always mounted in the same direction, the fitting accuracy between the key and the key groove does not need to be as high as the conventional one, and only the indexing position accuracy is ensured. It will be good. Even if the clearance between the key and the key groove is large, the workability is improved and the time required for attaching and detaching the cutter is shortened.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 to 3 show that a throw-away tip 2 is provided on the inner circumference of a cutter body 1 having a hollow disc.
Internal pin milling that is incorporated into the clamp mechanism so that when the rotation trajectories of each cutting edge are combined, the rotation trajectories are drawn to match the shape of the crankshaft pin that is the work material. It shows a cutter.

An adapter 3 having a diameter larger than that of the cutter body 1 and having a hollow disk shape is fastened and fixed to a main shaft of a machine tool with a bolt 4 to form a main shaft end integrally with the main shaft. An inlay 5 is provided on the inner peripheral side of the adapter 3, and the cutter body 1 is fitted into the inlay 5 to determine the diametrical position.

On the inner circumference of the adapter 3, a square key 6 projecting toward the center of the disc is fastened and fixed by a bolt 7. The keys 6 are located in four places and are evenly distributed along the circumference. The cutter body 1 faces the protrusions of these keys 6.
Four keyways 8 are arranged on the outer periphery of the. The key 6 and the key groove 8 are fitted to position the cutter main body 1 in the circumferential direction, and the rotational force of the main shaft is transmitted to the cutter main body 1 by this key fitting.

The cutter body 1 inserted at the end of the spindle is fixed as follows. One is a method of directly tightening and fixing to the end of the main shaft with a bolt 9, and the other is using a pressing piece. Further, these may be used in combination.

A method using the pressing piece will be described below. The adapter 3 has a small diameter counterbore 10 formed from the front.
The center of the hole is the same as that of the counterbore hole 10. The diameter of the hole is larger than that of the counterbore hole 10 and the depth of the hole is shallow. A plurality of stepped counterbore holes formed by the counterbore hole 11 formed in the above are provided along the circumference. In the cutter body 1,
The same number of recesses 12 that draw an arcuate arc that complements the incomplete arc of the counterbore hole 11 are arranged in opposition to the stepped counterbore holes. The pressing piece 13 is composed of a cylindrical portion 14 that fits in the counterbore hole 10 and a flange 15. Flange 15
The appearance of is a drum shape formed by straight lines and curved lines,
The arc portion has substantially the same curvature as the counterbore 11. A bolt hole penetrates through the center of the presser piece 13 and is tightened by a bolt 16 that is screwed into the adapter 3. A retaining ring 17 is engaged with the bolt 16 at a position corresponding to the bottom surface of the pressing piece 13 so that the pressing piece 13 integrally floats when the bolt 16 is loosened.

1 and 2 are views showing a state in which the cutter body 1 is clamped and fixed by a pressing piece 13.
The recess 15 of the cutter body 1 is pressed by the flange 15 of the pressing piece 13. A pin 18 is fixed to the adapter 3 as a rotation direction stopper of the pressing piece 13. When removing the cutter body 1, loosen the bolt 16 and press the presser piece 1
3 is rotated 90 ° to the left so that the flange 15 is not caught in the recess 12. The pin 18 also serves as a stopper when turning left.

In addition to the above configuration, the cutter body 1
A screw hole 20 that is substantially perpendicular to a side wall 19 that is located at a rear position in the cutter rotation direction of the key groove 8 is bored therein, and a ball plunger 21 and a set screw 22 for positioning and fixing the ball plunger 21 are embedded therein. The ball plunger 21 is composed of a ball 23 and a coil spring 24 that acts to push the ball 23, and the ball 23 portion can press the side surface of the key 6 when the key 6 is fitted in the key groove 8. On the side wall 1
It projects more than 9.

When the keys are fitted, the key 6 and the key groove 8 are always in contact with each other at the front position in the cutter rotation direction due to the spring effect. Therefore, regarding the clearance between the key 6 and the key groove 8 which is conventionally required to be highly accurate,
It is not necessary to have higher precision than before, and the clearance is widened, so that the workability of attaching and detaching the cutter is improved. Since the tip end on which the spring is pressed is the ball 23, the verticality between the side wall 19 and the screw hole 20 does not matter. The contact between the key 6 and the spring component is also smoothed, and the work can be performed more easily.

The spring may be a disc spring or a leaf spring. For example, a J-shaped leaf spring is screwed to the side wall 18 and a spring force is applied so as to widen the clearance between the key 5 and the key groove 7.

[0015]

As described above, according to the present invention, the workability when attaching and detaching the internal type pin milling cutter to the spindle end of the machine tool is improved, and particularly the mounting work is speeded up. Also, it will not be forcibly installed,
Keyway damage is reduced.

[Brief description of the drawings]

FIG. 1 is a front view showing one embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along the line AA of FIG.

FIG. 3 is an enlarged sectional view of a key groove portion of the cutter body 1.

[Explanation of symbols]

 1 Cutter main body 2 Throw-away tip 3 Adapter 6 Key 8 Key groove 13 Presser piece 21 Ball plunger 22 Set screw 24 Coil spring

Claims (2)

[Claims] 1. A key groove 8 is provided on the outer periphery of a cutter body 1 having a hollow disk, and the key 6 provided at the end of a spindle of a machine tool and the key groove 8 are fitted and fixed by fitting. In the pin milling cutter that is driven to rotate, a spring component such as a coil spring, a disc spring, and a leaf spring is incorporated in the side wall 19 of the key groove 8 located rearward in the rotational direction of the cutter body 1 and one end thereof is projected. , When the key is fitted,
A pin milling cutter configured such that a pressing force acts in a direction in which the clearance between the side surface of the key 6 facing the side wall 19 is expanded by the spring component. 2. A ball plunger 21 as a spring component.
The pin milling cutter according to claim 1, wherein the pin milling cutter is incorporated.