JPH078164Y2 - Penetration cone - Google Patents

Description

TECHNICAL FIELD The present invention relates to a cone with an improved tip edge line of a through cone for wood processing or similar processing.

2. Description of the Related Art A general penetrating cone is, for example, as shown in FIG. 6, a double-edged tip whose tip cutting edge is formed into a substantially straight line at a predetermined angle from the cutting edge corner of the side outer peripheral cutting edge, and the intersection of the cutting edge lines is a cone. It is ground so that it becomes the center of rotation.

Problems to be Solved by the Invention When a through hole is formed in this way and a through hole is to be formed in a pillar, a plate, etc. Due to the cutting component force acting on the workpiece, a partial stress concentration occurs in the work material, and the periphery of the outlet is often chipped as shown in FIG. 7, resulting in a problem that the quality of the product is deteriorated. As a countermeasure against this, it is possible to reduce this chipping by reducing the angle θ of the tip cutting edge line with respect to the axis of the cone and reducing the cutting component force below the corner to reduce the partial stress concentration of the work material. This is possible, but this causes the disadvantage that the cutting edge portion at the tip becomes long and the processing distance to the hole penetration also becomes long. If the tip cutting edge is formed so as not to cause chipping at the exit of the hole due to the cutting component acting downward, depending on its shape, a cutting component force that lifts the material upwards works and the tip cutting edge of the cone is completely formed on the material. When entering, a chip is generated around the entrance of the hole, and in a material having a decorative plate laminated on the surface, the decorative plate is peeled or chipped.

The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide an inlet portion when a hole of a cutting material is cut to a predetermined diameter and an outlet portion immediately before penetration. The purpose of the present invention is to provide a penetrating cone that can obtain a beautiful opening without chipping.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention provides a tip cutting edge portion and a side surface cutting edge portion in which a spiral chip discharge groove is formed at a predetermined twist angle from the blade tip portion to the shank portion. In a penetrating cone having a single-blade or a double-blade, the tip cutting edge line is formed by a convex bending line in which a straight line is bent once or more between the cutting edge corner portion of the side surface outer periphery and the tip. By this bending, the apex angle of the cutting edge is formed to be an obtuse angle, and the finishing blade portion closest to the side surface outer peripheral cutting edge is formed so as to be located on the plane including the conical axis or in the vicinity thereof.

It is preferable that the angle between the finishing blade line closest to the side face outer peripheral cutting edge and the conical axis line is 30 ° or less and the apex angle of the cutting edge is 90 ° to 150 °.

Action Before the penetration cone is cut into the wood and the diameter of the hole at the entrance becomes the cone diameter, the finishing edge of the convex tip cutting edge line is formed so as to be located on or near one plane including the cone axis. Therefore, the inclination angle with respect to the conical axis line (the angle seen from the direction in which the finishing blade line and the conical axis line overlap) becomes small, and the cutting component force for lifting the material upward becomes small. Also in the gap where the cone penetrates, the angle between the finishing blade line closest to the side outer peripheral cutting edge and the cone axis line is small, so the cutting component force in the axial direction acting downward is small, and the partial stress concentration of wood Is reduced, so that there is no damage to the opening edges of the work material laminated to the surface.

Example 1 (two-blade) Hereinafter, description will be given with reference to FIGS. 1 to 3.

The penetrating cone has a shank portion 2 in which two parallel surfaces are cut for attaching a spanner to a mounting screw portion 1 screwed to the tip of the main shaft of a drilling machine, and a conical portion 3 is integrally formed coaxially from the shank portion 2. At the tip of the conical portion 3, there is brazed a cemented carbide material that coaxially forms the conical cutting edge portion 4. Cutting blade 4 and cone 3
In this case, a total of two rake faces 5 extending in the axial direction and having a predetermined lead are symmetrically cut with respect to the conical axis, and a spiral chip discharge groove 6 having a twist angle is formed. The ridge line formed by the intersection line between the rake face and the outer circumference of the cutting edge portion 4 forms the side surface outer peripheral cutting edge line 7, and the ridge line formed by the intersection line between the rake face and the conical surface forms the tip cutting edge line 9. And the tip cutting edge line 9 is the cutting edge part 4
A straight line is formed from the cutting edge corner portion 8 of the side surface outer peripheral cutting edge line to the center of the tip in a convex shape by a bending line that is bent once or more. Further, at least the finishing blade portion of the tip cutting edge line 9 that is closest to the side surface outer peripheral cutting edge is formed so as to be located on a plane including the conical axis line or to be located near that surface.

The flank 10 forms the rear side of the tip cutting edge and the side peripheral cutting edge in the chip discharge groove 6.

By forming in this way, the tip cutting edge line of the portion of the side surface outer peripheral cutting edge near the cutting edge corner portion 8, that is, the finishing blade portion that determines the diameter of the hole does not follow the twist of the chip discharge groove and the tip cutting edge line. Does not fall backward due to the twist, and this part reduces the cutting component force for lifting the material upward. Further, the angle α formed by the tip cutting edge line following the cutting edge corner portion 8 on the outer periphery of the side face and the conical axis line is preferably 30 ° or less in order to further reduce the cutting component force acting downward. Further, in order to maintain a certain low cutting resistance and shorten the stroke until the through hole is formed, the apex angle is an obtuse angle and is generally 90 ° to 150 °, and a preferable value is 120 °.

This penetration cone is screwed to the main shaft of the hole punching machine with a mounting screw portion, and when a processed material such as lumber is cut by a required rotation, drilling is started by the central portion of the tip cutting edge line 9. As the cutting is performed, the tip cutting edge line 9 formed of a convex bending line approaches the cutting edge corner portion 8 of the side surface outer circumferential cutting edge 7, and the angle α of the tip cutting edge line with respect to the conical axis line becomes 30 ° or less and the tip is formed. Since the cutting edge line is located on the plane including the conical axis line or in the vicinity thereof, the cutting component force for lifting the material upward becomes small, and the entrance hole diameter is drilled to a predetermined size without missing the hole cut. When the cutting is further continued and reaches the exit of the through hole, a large component force working downward at the tip cutting edge line of the central part with a relatively large angle with the conical axis causes chipping at the periphery of the small exit opening. However, as the diameter of the conical hole is gradually approached, the finishing blade portion of the tip cutting edge line 9 approaches the cutting edge corner portion 8 on the outer periphery of the side surface, and the cutting component force acting downward is reduced, so that the outlet side opening edge No unreasonable force is applied to the thinned part of the and the opening does not chip.

In the test using this penetration cone ○ Work material: Particle board laminated with melamine resin on both sides ○ Thickness: 15mm ○ Spindle speed N: 3500r.pm ○ Cutting feed Fz: 3m / min No chipping was observed around the hole at both the entrance and the exit.

Example 2 (single blade) An explanation will be given based on FIGS. 4 to 5.

The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In this example, since there is only one cutting edge, it is natural that there is only one chip discharge groove 6 having a twist angle, and the relief portion on the rear side of the cutting edge extends over about a semicircle from the viewpoint of strength.

In terms of action, there is no difference from double-edged blades.

EFFECTS OF THE INVENTION Since the present invention is configured as described above, the present invention has the following effects.

Claim 1, This is the case where the cutting component force in the direction of the cone axis becomes small and the stress concentration partially disappears near the entrance and exit of the hole of the work material where the predetermined hole diameter is reached, resulting in chipping of the rim. Can be prevented, the yield of products can be improved, and the finish can be cleaned. In particular, the improvement of the perforated surface in the work material in which resin plates are laminated on both sides is remarkable. Further, since the tip cutting edge line is a convex bending line from the cutting edge corner portion to the tip and the cutting edge apex angle is an obtuse angle, the machining distance until the through hole is formed is shortened.

According to the second aspect, the cutting component force in the direction of the conical axis is further reduced.

[Brief description of drawings]

FIG. 1 is a side view of a double-edged penetrating cone of the present invention, FIG. 2 is a side view in which a part is omitted in a direction perpendicular to FIG. 1, and FIG.
FIG. 4 is a front view of a single-blade penetration cone of the present invention, FIG. 4 is a front view of a single-blade penetration cone of FIG. 4, and FIG. FIG. 7 and FIG. 7 are cutting state diagrams thereof. 3 ... Cone part, 4 ... Tip cutting edge part 6 ... Chip discharge groove, 7 ... Side outer peripheral cutting edge line 8 ... Cutting edge corner part, 9 ... Tip cutting edge line

Claims (2)

[Scope of utility model registration request] 1. A penetrating hole having a spiral chip discharge groove formed at a predetermined twist angle from the tip of the cutting edge to the shank and having a tip cutting edge portion and a side cutting edge portion and comprising one or two blades. In the cone, the tip cutting edge line is formed by a convex bending line in which a straight line bends one or more times between the cutting edge corner portion on the outer periphery of the side surface and the tip, and by this bending, the cutting edge apex angle is formed to be an obtuse angle. A penetrating cone, wherein the finishing blade portion closest to the outer peripheral cutting edge is formed so as to be located on a plane including the cone axis or in the vicinity thereof. 2. The angle between the finishing blade line closest to the side surface outer peripheral cutting edge and the conical axis line is 30 ° or less, and the cutting edge apex angle is 90 ° to 150 °.
The penetrating cone according to claim 1, wherein