JPH0129841B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an extrusion molding machine used for molding cemented carbide before sintering, and particularly for forming a spiral hole inside a molded body for a drill. This invention relates to an extrusion molding machine for drills.

[Prior Art] FIG. 4 is a partial view of a drill used in a drilling machine or the like. Inside this type of drill 1, oil holes 2 and 3 are generally formed in a spiral shape along the blade part, and oil is passed through these oil holes 2 and 3 during drilling to cool or cool the drill. Wear is prevented.

Now, when such a drill 1 is manufactured from carbon steel or high-speed steel, the above-mentioned spiral oil holes 2 and 3 can be formed very easily.
However, when the drill 1 is made of carbide, the oil hole cannot be formed in a spiral shape. Therefore,
A drill made of carbide usually has an oil hole as shown in FIG. That is, the oil hole 4 passes through the center of the drill, and one end opens at the base end of the drill, while the other end splits into two parts near the tip of the drill, each opening at the tip of the cutting blade.

Here, this carbide drill is manufactured as shown below. First, a combination of the raw material and the wax material is molded using an extrusion molding machine through a mold whose inner peripheral surface has a spiral surface, and then the above-mentioned oil holes 4 are formed and then sintered.

[Problems to be Solved by the Invention] Normally, when the cutting blade at the tip of a drill becomes worn, it is necessary to polish it. However, the above-mentioned carbide drill cannot sharpen all of the oil holes that are divided into two hands, so the length that can be polished is limited and the service life is short.

In view of the above circumstances, an object of the present invention is to provide an extrusion molding machine that can form a spiral oil hole in a carbide drill.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a material cylinder and a mold provided at the tip of the material cylinder, and the material inserted into the material cylinder is , an extrusion molding machine for a drill that molds a molded body for a drill by extruding it from a molding port of the mold, wherein the inner periphery of the molding port is a spiral surface, and a core is provided at the tip of the material cylinder. A support member is provided, and the core support member is composed of a frame fitted into the material cylinder and a transition member fixed within the frame, and has a plurality of gaps, and has a plurality of gaps. A spiral core having an inclination equal to the spiral surface of the molding opening is located at the center of the transition member on a circumference centered on the center point of the transition member, and the tip thereof is connected to the molding The tip of the spiral core is located in the mouth, and the tip of the spiral core is set at a position corresponding to the thick part of the molded body for a drill.

[Operation] With the above-described configuration, the material in the material cylinder is extruded through the gap between the core supporting members while rotating along the spiral surface of the mold opening, thereby forming the drill mold. A spiral outer shape of the body is formed, and a spiral shape is provided between a circumference centered on the center point of the transition member and a position in the molding mouth and has an inclination equal to the spiral surface. A spiral space (oil hole) is formed by the core in the thick part of the molded body for a drill.

[Embodiment] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing the configuration of an extrusion molding machine according to an embodiment of the present invention. In the figure 5
is a material cylinder, and 6 is a piston that moves in the horizontal direction in the figure within this material cylinder 5. Tip 5 of material cylinder 5
A cylindrical die holder holder 7 whose outer diameter is equal to the outer diameter of the material cylinder 5 and whose inner diameter is slightly smaller than the inner diameter of the material cylinder 5 is attached to a. A cylindrical die holder 8 is fitted into the die holder 8 so that it cannot be pulled out in the right direction, and a cylindrical mold 9 is fitted into the inner periphery of the die holder 8 so that it cannot be pulled out in the right direction. In this case, the rear end 8a of the die holder 8 has a taper such that its inner diameter becomes narrower toward the tip. In addition, the shape of the molding opening of the mold 9, 9a, is as follows:
As shown in Fig. 2, it has the cross-sectional shape of a drill, and its inner circumferential surface forms a spiral surface. By pushing through the
Drills are being molded.

Moreover, 10 is a core support member. As shown in FIG. 3, this core support member 10 includes a frame 10a whose outer diameter is the same as the inner diameter of the material cylinder 5, and a cross-shaped transfer member 10b fixed within this frame 10a.
As a result, the core support member 10 has fan-shaped gaps 10c, 10c, . Two cores 11 and 12 are planted at the center of one surface of the transition member 10b at an interval of 180° on the circumference centered on the figure center point O of the frame 10a. The diameter of the circumference in this case is equal to the distance l from the thick part P1 of one cutting blade to the thick part P2 of the other cutting blade of the drill shown in FIG. Further, the cores 11 and 12 are each wire-like members, and the length thereof is longer than the distance from the tip of the material cylinder 5 to the rear end of the mold 9, as shown in FIG. The cores 11 and 12 are bent at an inclination equal to the inclination formed by the spiral surface on the inner circumference of the mold 9, and form part of a spiral centered on the center point O. And, such a core support member 10
is unrotatably fitted into the tip 5a of the material cylinder 5 with the cores 11 and 12 facing the mold 9 side. In this case, the frame 10a is in contact with the rear end of the die holder holder 7, and the tips of the cores 11 and 12 are located within the molding opening 9a of the mold 9. Further, in this case, the tips of the cores 11 and 12 are always in the thick portion P within the molding opening 9a.
1 or P2.

In the above configuration, when the material inserted into the material cylinder 5 is pressed to the right in FIG. 1 by the piston 6, the material passes through the fan-shaped gaps 10c, 10c... 8
Then, it moves to the rear end of the mold 9 and is pushed into the molding opening 9a of the mold 9. Further, as the piston 6 continues to move, the material is molded into the shape of a drill and advances toward the tip of the mold 9 while rotating along the spiral surface of the molding opening 9a. At this time, inside the material, a space from which the material is removed by the cores 11 and 12 is formed in a spiral shape.
Its position is always the thick part P1 of the cutting blade of the drill,
It is P2. Once the molded object has been molded to an appropriate length, the movement of the piston 6 is stopped and the molded object is removed. Inside this molded object, as shown in FIG. 4, two spiral through holes extending from the tip to the base are formed. Next, this molded object is sintered to form a drill.

The interior of the carbide drill manufactured in this manner has a spiral oil hole formed in the same manner as that manufactured from carbon steel or high speed steel.

[Effects of the Invention] As explained above, the present invention includes a material cylinder and a mold provided at the tip of the material cylinder, and the material inserted into the material cylinder is passed through the molding opening of the mold. In an extrusion molding machine for a drill that molds a molded body for a drill by extrusion, the inner periphery of the molding port is formed into a spiral surface, and a core support member is provided at the tip of the material cylinder. The core support member is composed of a frame fitted into the material cylinder and a bridging member fixed within the frame, and has a plurality of gaps, and a center portion of the bridging member. A spiral core having an inclination equal to the spiral surface of the molding port is provided on a circumference centered on the center point of the passing member, with its tip located within the molding port. On the other hand, since the tip of the spiral core is set at a position corresponding to the thick part of the molded body for a drill, the material in the material cylinder is Through the
The mold is rotated and extruded according to the spiral surface of the molding opening to form a spiral-shaped outer shape of the molded body for a drill, and the inside of the molding opening is extruded from a circumference centered on the center point of the transfer member. By forming a spiral space in the thick part of the molded body for a drill by a spiral core having an inclination equal to the spiral surface, the spiral core is provided up to the position of Carbide drills with linear oil holes can be manufactured smoothly.
The lifespan of carbide drills can be dramatically extended.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the configuration of an extrusion molding machine according to an embodiment of the present invention, and FIG.
The arrow view of FIG. 1 showing the shape of the molding opening 9a,
The figure is a front view showing the shape of the core support member in which the cores 11 and 12 are implanted, and FIGS. 4 and 5 are
FIG. 3 is a partial view showing a drill and an oil hole formed inside the drill. 5...Material cylinder, 5a...Tip, 9
...mold, 9a ... molding mouth, 10 ... core support member, 10a ... frame, 10b ... transfer member, 1
0c...= between, 11, 12...core, O...center point.

Claims (1)

[Scope of Claims] 1. A molded body for a drill comprising a material cylinder and a mold provided at the tip of the material cylinder, and by extruding the material inserted into the material cylinder from the molding opening of the mold. In an extrusion molding machine for a drill, the inner periphery of the molding port is a spiral surface, and a core support member is provided at the tip of the material cylinder, and the core support member is configured to mold the material. It is composed of a frame fitted into a cylinder and a bridging member fixed within this frame, and has a plurality of gaps, and a center point of the bridging member, which is a central part of the bridging member. A spiral core having an inclination equal to the spiral surface of the molding port is provided on a circumference centered at , with its tip located within the molding port, while An extrusion molding machine for a drill, characterized in that a tip end of the child is set at a position corresponding to a thick part of the molded body for a drill.