CN104400079A - Twist bit for carburizing steel - Google Patents

Abstract

The invention relates to a twist bit for carburizing steel. A cutter body is provided with a spiral chip discharging groove; the cross section of the chip discharging groove is shaped like a multiple rolling type curve; two rear cutter surfaces are ground at the position of the end surface of the head portion of the cutter body; an intersection line of the rear cutter surfaces and the chip discharging groove forms into a main cutting edge which is shaped like a multiple bending edge; an intersection line of the two rear cutter surfaces forms into a cross edge; a position of the cutter body, which is close to the chip discharging groove, forms into an edge; an inner edge is ground between the main cutting edge and the cross edge; an intersection point of the main cutting edge and the edge is a cutter point; the continuous transition is formed between the inner edge and the main cutting edge. The multiple bending type main cutting edge is formed due to the multiple rolling type chip discharging groove, multiple bending shaped chips can be obtained during cutting due to the edge shape, namely that a plurality of reinforcing ribs are etched on the cross section of the chips, and accordingly the strength of the chips is improved, the machining reinforcement effect is apparent. The chip breaking is easy along with the improvement of the strength of the chips, the chip discharging is smooth, and accordingly the efficient precision drilling of the carburizing steel is implemented.

Description

Twist drill bit for carburizing steel

technical field

The invention relates to a tool for cutting metal with high speed and high efficiency, in particular to a twist drill bit for cutting carburized steel.

Background technique

Carburized steel has good machinability, small processing deformation, and quite good fatigue resistance. Due to its extremely high cost performance advantage, it is mainly used for gears, shafts, pistons and various special parts of automobiles and aircrafts. Due to the low carbon content of carburized steel, usually not higher than 0.2%, the elongation rate of the material before heat treatment is >10%. The cause of chips leads to processing interruption, poor quality and knife breaking accidents.

In order to improve processing efficiency and achieve high-efficiency cutting, it is necessary to develop a new type of drill bit for carburized steel, which is easy to tangle with chips.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art and provide a twist drill for drilling carburized steel.

The purpose of the present invention is achieved through the following technical solutions:

The twist drill bit for carburizing steel includes a cutter body and a shank. The cutter body and the shank are coaxial cylinders centered on the same central axis. The cross-section of the flute is in the shape of multiple undulating curves, and the end face of the cutter head is ground with two flanks. The intersection line between the flank and the flute forms the main cutting edge, and the main cutting edge is in a multiple zigzag shape. The intersection line of the two flanks forms a chisel edge, the position of the cutter body near the chip flute forms an edge, and an inner edge is ground between the main cutting edge and the chisel edge, and the intersection point of the main cutting edge and the edge is the tool tip. There is a continuous transition between the inner edge and the main cutting edge.

Further, in the aforementioned twist drill bit for carburizing steel, the main cutting edge has a zigzag shape with three peaks and two valleys.

Further, in the aforementioned twist drill bit for carburizing steel, wherein, the continuous transition between the inner edge and the main cutting edge has no sharp point.

Substantive features and progress of the technical solution of the present invention are mainly reflected in:

The twist drill for carburizing steel is designed with multiple undulating chip flutes, and then forms a multiple zigzag main cutting edge. When cutting, this blade shape can obtain chips in the form of "multiple zigzags", which is equivalent to marking multiple places on the chip section. Reinforcing ribs, which in turn increase the chip strength, making the processing strengthening effect more obvious. With the improvement of chip strength, chip breaking becomes easier and chip removal is smoother, realizing high-efficiency precision drilling of carburized steel. It is very suitable for drilling medium carbon steel and medium carbon alloy steel such as 45# and 40Cr under normalizing condition.

Description of drawings

Below in conjunction with accompanying drawing, technical solution of the present invention will be further described:

Fig. 1: Structural schematic diagram of the present invention;

Figure 2: Schematic cross-sectional view of the flute;

Figure 3: Schematic diagram of the structure of the head of the cutter body;

Figure 4: Schematic representation of the main cutting edge.

Detailed ways

As shown in Figure 1, the twist drill for carburizing steel includes a cutter body 1 and a shank 2. The cutter body 1 and the shank 2 are coaxial cylinders centered on the same central axis, and the shank 2 is a circle with high precision. A section of cylinder, when in use, clamps the shank 2 through the tool handle to transmit the power of the machine tool, so that the tool rotates and has the cutting ability. A spiral chip flute 3 is ground on the cutter body 1, and two flanks 4 are ground on the end face of the cutter body head, and the intersection line between the flank face 4 and the chip flute 3 forms a main cutting edge 5, The intersection line of the two flank surfaces 4 forms a chisel edge 6, and at the position of the cutter body 1 close to the chip flute 3, the excess part of the cutter body 1 is ground by the edge cleaning process, leaving only a spiral cylindrical surface, forming edge 7.

As shown in FIG. 2 , the cross section of the flute 3 is in the shape of multiple undulating curves, which is formed by grinding with a profiled grinding wheel.

As shown in Figure 3, an inner edge 9 is ground between the main cutting edge 5 and the chisel edge 6, which is used to further modify the chisel edge to improve the centering ability of the drill. The intersection point of the main cutting edge 5 and the edge 7 is the tool tip 8, and the inner edge 9 and the main cutting edge 5 are continuously transitioned without sharp points. By adjusting the relative positions and angles among the inner edge 9, the chisel edge 6 and the main cutting edge 5, the shape of chips can be improved to facilitate chip breaking.

As shown in FIG. 4 , the main cutting edge 5 is a multiple zigzag blade shape, usually in the form of 2.5 heavy, that is, three peaks A and two valleys B.

In summary, the twist drill bit for carburizing steel of the present invention is designed with multiple undulating chip removal grooves, and then forms a multiple zigzag main cutting edge. When cutting, this blade shape can obtain chips in the form of "multiple zigzags", which is equivalent to The cross-section of the chip is marked with multiple reinforcing ribs, which in turn improves the strength of the chip and makes the processing strengthening effect more obvious. With the improvement of chip strength, chip breaking becomes easier and chip removal is smoother, realizing high-efficiency precision drilling of carburized steel. It is very suitable for drilling medium carbon steel and medium carbon alloy steel such as 45# and 40Cr under normalizing condition.

It should be emphasized that: the above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention are valid. Still belong to the scope of the technical solution of the present invention.

Claims (3)

1. Twist drill bit for carburizing steel, including cutter body and shank. The cutter body and shank are coaxial cylinders centered on the same central axis. It is characterized in that: the cutter body is provided with a spiral chip removal groove , the cross-section of the chip flute is in the shape of multiple undulating curves, and the end face of the cutter head is ground with two flanks. Blade shape, the intersection line of two flanks forms a chisel edge, the position of the cutter body close to the chip flute forms an edge, and an inner edge is ground between the main cutting edge and the chisel edge, and the intersection point of the main cutting edge and the edge is The tip, the inner edge and the main cutting edge have a continuous transition. 2. The twist drill bit for carburizing steel according to claim 1, characterized in that: the main cutting edge is in a zigzag shape with three peaks and two valleys. 3. The twist drill bit for carburizing steel according to claim 1, characterized in that: the continuous transition between the inner edge and the main cutting edge has no sharp point.