KR20040009908A - drilling tool with twisted water hole - Google Patents

Abstract

PURPOSE: A drill tool having a twisted water pipe is provided to have a spiral angle and a sectional view along the entire area of a chip groover at the water pipe. CONSTITUTION: A drill tool having a twisted water pipe is composed of a drill head(1), cutting inserts(11,12), a chip groover(2) twisted in a spiral shape, a rib(3) formed at the same angle with the chip groover, and two of water pipes having an water outlet. The drill head includes pockets containing the cutting inserts, and a chip guide. The cutting inserts are fixed at the pocket of the head displaced in an asymmetrical manner. The chip groover extends from the chip guide of the head to a flange(4). The water pipes are formed from a shank(5) to the flange in a linear shape and formed in the rib near the chip groover in a spiral shape.

Description

Drill tool with twisted water hole

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drill tool for processing holes, and more particularly, to a drill tool provided with a spiral torsion cooling water supply pipe in a drill body in order to smoothly discharge chips generated during processing.

In general, since drilling is performed in an enclosed space, the discharge of chips generated during machining is a very important factor in cutting performance, and supply of cooling water is essential for good chip discharge.

In addition, it is necessary to increase the chip groover, which is the transportation path of the chip, to minimize the interference and resistance with the chip.

In order to satisfy the above conditions, it is effective that the coolant pipe is installed inside the drill body, but on the contrary, it is a factor that lowers the strength of the drill body.

On the other hand, when the spiral angle of the rib is small in a general drill tool, a straight coolant pipe having a small angle may be installed to avoid the chip groover, but the cross-sectional position of the coolant pipe may vary depending on the position in the direction of the center line of the drill body. As a result, the strength of the drill body is changed and problems such as vibration during cutting are difficult to obtain a good cutting effect.

On the other hand, when the chip groover's helix angle is large, it is impossible to install a straight coolant pipe.

Coolant pipes should also be designed so that a greater amount of coolant is ejected by applying stronger pressure at their outlets.

In addition, the chip discharged during processing is sandwiched between the drill body and the machined hole, causing problems such as vibration, and thus it is necessary to induce the chip in an optimal direction and discharge the chip.

In addition, since the chip separated from the workpiece collides with the chip guide surface under strong pressure, it can be severely dug and shorten the life of the drill body. Therefore, the coolant pipe is positioned so that the chip is discharged well without reducing the strength of the drill body. The chip groover shall be designed to take into account the chip discharge and the strength of the body, and a hardened part shall be separately installed on the chip guide surface.

In particular, the drill operation often causes sudden troubles due to poor chip evacuation, which requires a cutting insert having a stronger edge.

It is an object of the present invention to provide a drill tool capable of good chip evacuation without reducing the strength of the drill body.

According to an embodiment of the present invention for achieving the above object, a drill head portion having a pocket for receiving a cutting insert and a chip guide surface for guiding the generated chip, and is fixed to the pocket of the head portion and between the centerline and the periphery Are asymmetrically arranged with overlapping regions in the outer edge, the outer insert protrudes out and the inner insert is positioned near the centerline with one corner portion beyond the centerline, starting from the chip guide surface of the head and extending to the flange And a chip groover installed at a helix angle twisted from the center line, ribs formed at the side of the chip groover and formed at the same helix angle as the chip groover in the direction of the center line from the end of the head to the flange, and a straight line from the shank to the flange. Formed into a shape and immediately before the drill head portion. Gruber linear chip area in a drilling tool with a twisting cooling water pipes consisting of a cooling water pipe in the cooling water outlet is provided so that the rib is formed in a curved shape with the same helix angle and chip Gruber injected in the drill body outside the cooling water on the head portion.

1 is a front view of a drill tool according to the present invention

2 is a bottom view of a drill tool according to the invention

3 is an enlarged front view of a drill head portion;

4 is a partially enlarged view of the bottom of the drill head;

5 is a partially enlarged plan view of a drill head part;

6 is an enlarged side view of a drill head portion;

7 is a cross-sectional view taken along the line C-C of FIG.

8 is a cross-sectional view taken along the line A-A and line B-B of FIG.

9A to 9C are exemplary views showing a cross section of the hardened surface of the drill head portion.

10 is a front view and a cross-sectional view showing an example of a seal used in the present invention

FIG. 11 is a left side view of FIG. 2

12 is a front view and a cross-sectional view of the cutting insert applied to the present invention.

Explanation of symbols for main parts of the drawings

1 drill head portion 2 chip groover

3: rib 4: flange

5: shank 6,7: coolant pipe

6a, 7a: Coolant outlet 11: Outer insert

12: inner insert 13a, 13b: pocket

14a, 14b, 15a, 15b: chip guide surface 21: restraint surface

51: seal seat 52: seal

53: end 60a, 60b: mirror screen

The drill tool according to the present invention includes a head portion (1) which is formed on the front surface of the drill body to be in contact with the workpiece first, and a cutting insert (11) (12) fixed to the head portion to cut the workpiece; A chip groover 2 accommodating chips discharged during processing, a rib 3 extending to the side of the chip groover, a flange 4 and a shank 5 for coupling the drill body to the processing equipment; , The cooling water pipe (6) (7) formed in the drill body.

The drill head portion 1 is composed of inner and outer inserts 11 and 12, pockets 13a and 13b for accommodating them, and chip guide surfaces for guiding chips generated during machining to chip groovers. The guide surface is composed of two surfaces: horizontal surfaces 14a and 14b which are slightly lower than the upper surface of the cutting insert, and vertical surfaces 15a and 15b having an angle of 80 ° or more and 150 ° or less with respect to the horizontal plane.

If the angle θ1 (θ2) (see FIG. 6) between the two surfaces is too small, the restraint of the chip becomes excessive, and if too large, the restraint of the chip becomes difficult, so the angle is designed between 80 ° and 150 °, and the cutting insert The chips generated by (11) and (12) are guided and restrained along the chip guide surface and then enter the chip groover (2).

At this time, the chip separated from the workpiece collides with the vertical surfaces 15a and 15b perpendicular to the cutting insert with a strong pressure, which causes damage to the drill body, thereby extremely shortening the tool life and abnormally flowing the chip. It can cause serious problems with the emission.

In order to prevent this, hardened surfaces 60a and 60b which are hardened to improve wear resistance are formed at portions of the chip guide surfaces where the chips collide with the vertical surfaces 15a and 15b. The hardened surfaces 60a and 60b are designed to have a circular shape, a square shape, or any irregular shape because the shape, the collision shape, and the impact area of the chip vary depending on the type of workpiece, cutting conditions, or processing method.

In addition, in order to form the hardened surfaces 60a and 60b, a hardened material such as cemented carbide may be inserted into and fixed to a portion where the chip collides, or the hardened surface may be formed by a method such as laser or high frequency heat treatment. .

And the hardened surface (60a, 60b) to act as a chip breaker when the chip discharge, as well as to adjust the flow direction of the chip according to the discharge direction and the shape of the chip to make the optimum chip shape 9a to 9c, it is designed to be horizontal, convex or concave with respect to the chip guide surface.

The outer insert 11 and the inner insert 12 of the drill head 1 overlap each other, each of which is disposed asymmetrically with respect to the centerline.

The outer insert 11 projects out of the circumference of the drill body by determining the size of the hole to be machined, and the inner insert 12 is positioned near the center line and one corner portion is located beyond the center line.

This is because the velocity is zero at the center line serving as the rotation axis, so as to position the cutting edge line by a predetermined distance (a) away from the center line as shown in FIG. 6.

As shown in FIG. 3, the outer insert 11 is disposed at a positive clearance angle θ3 to reduce friction between the workpiece wall and the insert, and the inner insert 12 cancels the cutting force applied by the outer insert and cuts the cutting force. Are arranged at a clearance angle of (−4) in order to balance.

Therefore, since the inner insert 12 and the outer insert 11 are disposed in the same direction and do not generate relative forces with each other, the drill body is warped in one direction. In the present invention, as shown in FIG. The inner insert 12 has a step (L1) ahead of the edge of the outer insert 11 to balance the force.

That is, since a larger cutting force is added to the outer insert 11 having a larger circumferential speed than the inner insert 12, the cutting edge of the inner insert is projected more than the cutting edge of the outer insert so that uniform cutting force is applied to each insert.

However, excessively protruding the inner insert 12 causes too much cutting force on the inner insert 12, which causes large warpage in the drill body, and thus normal cutting. Therefore, when using a rectangular insert, the corner edge of the inner insert is the outer side. It is designed to have a step of 0.1-0.2mm ahead of the insert.

The cutting inserts 11 and 12 have a corner angle θ5 of 90 as shown in FIG. In this case, four corners can be used.

In addition, the outer insert 11 and the inner insert 12 is of the same shape and size to be able to be mounted in any pocket, the cutting line is in a parallel form so as not to cause problems in the mounting direction.

This is to enable the use of a larger number of corners and to maintain the maximum corner angle so that the cutting edge strength of the cutting insert is stronger. Therefore, it is possible to perform stable work without trouble even under high feed conditions and to obtain good surface roughness. It becomes possible.

In addition, when the edge strength increases, it is possible to reduce the size of the corner radius, thereby reducing the cutting force to obtain better machinability.

The two chip groovers 2 connected to the chip guide surfaces 14a, 14b, 15a and 15b are passages for receiving chips generated from the outer insert 11 and the inner insert 12.

As shown in FIG. 1, the helix angle θ6 of each chip groover 2 is formed to be as large as possible so as not to weaken the strength of the drill body, which can discharge a larger amount of chips when the drill body rotates. To make it work.

However, when the spiral angle θ6 is formed too large, the strength of the tool is lowered, so this angle is designed to be 10-25 °.

As shown in FIG. 8, the cross-sectional area (S1) (S2) of each chip groover is formed to be as large as possible at the chip groover portion, but when the cross-sectional area of the chip groover is formed too large, the strength of the drill body is lowered. It should not exceed 60% range.

In this case, each chip groover cross-sectional area is installed at the ratio of the width of the chip generated from the outer insert 11 and the inner insert 12 to minimize friction with the chip and to facilitate the discharge of the chip, and is connected to the inner insert. The chip groover cross-sectional area S1 is larger than the chip groover cross-sectional area S2 connected to the outer insert.

However, if the difference in the size of each cross-sectional area is too large, the strength of the drill body is lowered and the power balance is broken, so the difference should not be more than 10%.

The cross section of the chip groover 2 is concave so that the chip can be constrained well in the chip groover without deviating outward from the circumference by the centrifugal force.

Since the inner insert 12 is machined at a relatively low cutting speed compared to the outer insert 12, a small chip is generated, and this small chip is drawn out of the drill body by centrifugal force during ejection, and then into the machined hole. It is often jammed, which causes violent vibrations during processing.

Therefore, the chip guide surface parallel to the inner insert 12 and the chip groover connected thereto have a concave small constrained surface 21 as shown in FIG. 8 so that these chips can be better guided and discharged inside the drill body. It is installed separately.

In this case, the chip of small size, which is intended to escape out of the body circumference by the centrifugal force, is guided back into the chip groover while being controlled by the restraining surface 21.

The rib 3 on the side of the chip groover 2 is installed to hold the drill body, and is formed at the same helix angle as the chip groover 2 in the direction of the center line from the position at which the drill head ends to the flange 4 and on any cross section. It is designed to have the same size and shape at the position, so that the strength of the drill body is uniform at the site where the ribs 3 are formed.

Also, the web thickness t at the portion where the rib 3 is formed is the same at any position in the cross section, and the web thickness t is increased at the circumferential diameter in order to improve the flow of the chip without reducing the strength of the drill body. It is designed to have a ratio of 15-25%.

Cooling water is essential for drilling operations.

This is used to discharge the generated chips out with strong pressure and to reduce friction in the chip groover 2 and to prevent the generated chips from damaging the cutting inserts 11 and 12.

To this end, coolant tubes (6) (7) are installed inside the ribs (3), which can be supplied with a sufficient amount of coolant without degrading the strength of the drill body and also allow the chip to be discharged without being disturbed. It must be designed so that it can

The two coolant tubes (6) (7) are installed with two holes located at 180 ° to each other at the same distance and parallel to the center line from the shank (5) at the rear to the flange (4) and in the rib (3) It is installed in the rib 3 in a shape bent at the same spiral angle θ6 as the chip groover 2 while being positioned at 180 ° with each other at the same size as the circumferential center line in the phase.

The two coolant tubes 6 and 7 are thus located radially 180 ° from each other at equal positions and distances to the centerline at any position on the cross section over the portion of the shank 5 where the ribs 3 are formed. The drill body in the part where the coolant pipe is installed maintains a constant strength regardless of the position.

Especially in the deep hole machining, the possibility of vibration is greatly increased when the strength of the drill body varies depending on the part, which makes it impossible to perform stable cutting, so it is very important to maintain the constant strength of the drill body regardless of the part.

These coolant pipes (6) (7) have a large cross-sectional area, which increases the flow of coolant, which is advantageous for cutting, but when too large, the strength of the drill body is reduced, so that the cross-sectional area of the drill body is 5 to 13%. Is designed.

Spiral coolant pipes (6) (7), which are installed up to just before the drill head (1), are connected to the end of the drill head, and these coolant pipes (6) (7) are circumferentially outer side of the drill body as shown in FIG. Direction has a coolant outlet 6a, 7a in the form of a straight line having an angle in the direction in which the coolant can be ejected.

Each of these cooling water outlets 6a and 7a is installed at the same distance from the center line, and if they have different distances, the connection with the torsional cooling water pipe becomes very difficult and this is a factor that significantly lowers the cooling water.

In addition, these coolant outlets 6a and 7a are installed to be inclined in the circumferential outer direction, so that the closer to the outlet, the more the centrifugal force increases, which increases the pressure of the coolant so that the coolant is injected at a strong pressure, and thus is generated during processing. The chip is guided and discharged quickly into the chip groover.

If the inclination angle θ7 of these cooling water outlets 6a and 7a is too large, the flow resistance of the cooling water increases, and if it is too small, the desired centrifugal force increase cannot be obtained, so it is designed in the range of 5 to 45 °.

In order to supply the coolant during lathe machining, a separate connection is required. In the conventional drill tool, a seal seat is installed at the flange 4 to supply coolant through the seal seat. The overall length of the body is increased to increase vibration during processing.

Therefore, in the present invention, the length of the flange is shortened to a minimum, and the seal seat 51 is installed at the end of the shank 5 in the form of a screw or bore, and thus the length of the drill body is shorter, so that vibration is suppressed as much as possible. do.

Especially in the case where the coolant pipes 6 and 7 are installed over the seal seat 51 in the shank 5, a special type of seal larger than the position of the coolant pipe is closely attached to the end of the shank to prevent leakage. It is necessary to prevent, in this case, as shown in Fig. 10 should be used a seal 52 of the form having an end 52a in close contact with the end of the drill body.

In the drill tool according to the present invention, since the coolant pipe has the same spiral angle and cross-sectional shape at all portions of the chip groover, it is possible to effectively supply the coolant without lowering the strength of the drill body.

In addition, since the coolant outlet of the drill head is installed at an angle, and the proper insert of the cutting insert is used, small chips are not discharged to the outer periphery of the drill body but are guided into the chip groover.

Claims (13)

A drill head portion having a pocket for receiving a cutting insert and a chip guide surface for guiding the generated chip; A cutting insert fixed in a pocket of the head portion and asymmetrically disposed with an overlapping area between the centerline and the periphery, the outer insert protruding outwards and the inner insert being disposed near the centerline such that one corner portion is located beyond the centerline; A chip groover extending from the chip guide surface of the head portion to the flange and installed at a spiral angle twisted from a center line; A rib installed at the side of the chip groover and formed at the same spiral angle as the chip groover in the centerline direction from the position where the head portion ends to the flange, The shank to flange is formed in a straight line with respect to the center line, and in the spiral chip groover portion immediately before the drill head portion, it is formed in the rib at the same spiral angle as the chip groover, and the cooling water outlet is provided so that the coolant is sprayed out of the drill body from the head portion. Drill tool with torsional coolant pipe, characterized in that it consists of two coolant pipes. The method of claim 1, The cutting insert is formed with a corner angle of 90 degrees or more and has a rectangular torsional coolant tube that can use four corners. The method of claim 1, And a torsional coolant tube in which the corner edge of the inner insert mounted to the drill head portion protrudes from the corner edge of the outer insert. The method of claim 1, And a chip guide surface of the drill head portion having a torsional coolant tube consisting of a horizontal plane lower than the cutting edge of the cutting insert and a vertical plane between 80 ° and 150 ° with respect to the horizontal plane. The method of claim 1, A drill tool having a torsional coolant tube formed to be twisted at an angle of 10 to 25 degrees. The method of claim 1, And a cross section of the chip groover having a concave shape so that the chip is constrained well and having a torsional coolant tube having a chip groover cross section area connected to the inner insert larger than a chip groover cross section area connected to the outer insert. The method of claim 6, A drill tool having a torsional coolant tube in which a cross sectional area of the chip groover connected to the inner insert and a chip groover connected to the outer insert is within 10%. The method of claim 1, And a torsional coolant tube having a chip restraint surface parallel to the inner insert and a chip groover provided with a constrained confinement surface in a circumferential position of the drill body. The method of claim 1, And a torsional coolant tube having a partially cured hardened surface formed on each chip guide surface perpendicular to the outer insert and the inner insert. The method of claim 8, And said hardened surface having a torsional coolant tube formed by inserting a separate hardened object or formed by heat treatment. The method of claim 10, And the hardened object has a torsional coolant tube in the shape of either horizontal, convex or concave with respect to the chip guide surface. The method of claim 1, Said two coolant tubes having the same distance and size on the cross section of all positions except the drill head portion and having a torsional coolant tube radially located at 180 ° to each other. The method of claim 12, A coolant outlet of the coolant tube having a torsional coolant tube formed at an equal distance from the center and inclined in a range of 5 to 45 ° in the circumferential direction of the drill body.