JP2005262330A - Throw-away type drill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a throw-away type drill for improving chip discharging performance in deep hole processing. <P>SOLUTION: A first oil hole 7A and a second oil hole 7B are formed inside a tool body 1A of the throw-away type drill 1. The first oil hole 7A is composed of a first main pipe 8A bored along the axis O of the drill 1 toward the tip side from a rear end surface of the tool body 1A, and a first branch pipe 9A bored by connecting a tip part of the first main pipe 8A and an opening part 10A turning to the tip side. The second oil hole 7B is composed of a second main pipe 8B bored along the axis O toward the tip side from the rear end surface of the tool body 1A, and a second branch pipe 9B bored by connecting a tip part of the second main pipe 8B and an opening part 10B arranged on a wall surface of a chip discharge groove 4. The second branch pipe 9B turns to the rear end side of the drill 1, and the opening part 10B is arranged on the rear end side more than the opening part 10A of the first branch pipe 8A. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a throw-away drill, and more particularly, to a throw-away drill having an oil hole in a tool body.

A conventional throwaway drill of this type is illustrated in FIG. This throw-away drill (1) has a shank (2) and a flange (3) on the rear end side of the tool main body, and two on the front end side of the tool main body are twisted around the axis (O). A chip discharge groove (4) is formed. Then, the throw-away tip (5) is screwed and fixed to the tip seat cut out at the tip of the chip discharge groove (4) with the fastening screw (6) to form a drill blade. The two throw-away tips (5) are displaced in the radial direction, and are divided into roles by the central blade tip and the outer peripheral blade tip.

An oil hole (7) passes through the inside of the tool body. The oil hole (7) is constituted by a main pipe (8) and a branch pipe (9). Of these, the main pipe (8) is a blind hole that is located away from the web portion and is drilled parallel to the axis (O) from the rear end surface of the tool body toward the tip. In the branch pipe (9), an opening position that is most effective in cutting is set, and the opening is opened by connecting the opening and the tip of the main pipe (8). By using two main pipes (8), the flow rate of the cutting fluid is sufficiently secured. (For example, see Patent Document 1)

Japanese Patent Laid-Open No. 2003-19614

However, in the above-mentioned conventional throw-away drill (1), although the flow rate of the cutting fluid is sufficiently secured, the depth of the drilled hole is lower than that of low carbon steel such as SS400 and SCM415 with poor chip control. However, when drilling a deep hole 4 times or more the outer diameter (D) of the drill blade of the drill (1), there is a problem that chip clogging occurs and machining becomes difficult. The following can be considered as the reason. The first reason is that as the depth of the processed hole becomes deeper, the time for contact with the wall surface of the chip and the chip discharge groove (4) and the inner wall surface of the processed hole becomes longer. This is because the waste discharging speed becomes low. The second reason is that, as the depth of the machining hole becomes deeper, the flow rate of the cutting fluid gradually decreases as it approaches the rear end side of the drill (1). This is because of the decrease.

This invention is made | formed in view of said situation, The objective is to provide the throw-away type drill which improved the chip discharge | emission property in deep hole processing.

In order to solve the above-described problems, the present invention provides at least one chip discharge groove on the outer peripheral surface of a tool body rotated about an axis line from the front end surface of the tool body toward the rear end side along the axis line. In the throw-away drill in which an oil hole is formed in the tool body, the oil hole is composed of a first oil hole and a second oil hole, and the first oil hole Includes a first main pipe drilled along the axis from the rear end face of the tool main body toward the front end side, and a front end portion of the first main pipe and an opening portion facing the front end side of the tool main body. The second oil hole includes a second main pipe drilled along the axis from the rear end surface of the tool body toward the front end side, and the second branch pipe. A second branch pipe formed by connecting a leading end of the main pipe and an opening provided in a wall surface of the chip discharge groove, A throw-away type characterized in that the branch pipe faces the rear end side of the drill, and the opening of the second branch pipe is provided closer to the rear end of the drill than the opening of the first branch pipe. It is a drill.

According to the present invention, in addition to the cutting fluid discharged from the first branch pipe, the cutting fluid discharged from the second branch pipe having an opening in the wall surface of the chip discharge groove, the drill blade and the chip discharge groove. A sufficient amount of cutting fluid can be supplied, and the cutting fluid discharged from the second branch pipe suppresses a decrease in the flow rate of the cutting fluid on the rear end side of the chip discharging groove. The frictional resistance caused by the contact between the inner wall surface of the machining hole and the chip is reduced, and the reduction of the chip discharge rate is prevented. In addition, chips that are clogged in the chip discharge groove can be forcibly discharged out of the processing hole. From the above effects, chip dischargeability in deep hole machining is improved. Here, as the deep hole machining capable of obtaining the above effect, a drilling process in which the depth of the machining hole is larger than three times the outer diameter (D) of the drill blade is preferable. A drilling process of 4 times or more the outer diameter (D) is particularly preferable because the above-described effect becomes remarkable.

Embodiments to which the present invention is applied will be described below with reference to the drawings. 1 to 7 are views showing a throw-away drill according to this embodiment. FIG. 1 is a front view, FIG. 2 is a plan view, FIG. 3 is a bottom view, and FIG. FIG. 5 is a cross-sectional view taken along the line CC in FIG. 1, and FIGS. 6 and 7 are views taken in the direction of arrows A and B in FIG. 4, respectively.

As shown in FIGS. 1 to 5, this throw-away drill (1) has a shank (2) and a flange (3) on the rear end side (right side in FIG. 1) of the tool body (1A). Two chip discharge grooves (4) are formed on the distal end side (left side in FIG. 1) of the main body (1A) with a twist around the axis (O). Then, the throw-away tip (5) is screwed and fixed to the tip seat cut out at the tip of the chip discharge groove (4) with a tightening screw (6) to form a drill blade. The two throw-away tips (5) are displaced in the radial direction, and are divided into roles by the central blade tip and the outer peripheral blade tip.

An oil hole (7) for supplying cutting fluid is provided inside the tool body (1A). This oil hole (7) consists of two types, a first oil hole (7A) and a second oil hole (7B).

The first oil hole (7A) is composed of a first main pipe (8A) and a first branch pipe (9A), and the first main pipe (8A) is located at the approximate center of the tool body (1A). It is one blind hole that is drilled linearly from the rear end surface of the main body (1A) toward the front end side. As shown in FIG. 4, the first branch pipe (9A) opens at two positions on the tip surface of the tool body (1A), and each of the opening (10A) and the first main pipe (8A) It is drilled as two independent holes connecting the tip. Both of these two first branch pipes (9A) face the tip side of the drill (1). The first branch pipe (9A) may be opened in the wall surface of the chip discharge groove (4) at the tip of the tool body (1A).

Similarly to the first oil hole (7A), the second oil hole (7B) includes a second main pipe (8B) and a second branch pipe (9B). The second main pipe (8B) is drilled linearly from the rear end surface of the tool body (1A) toward the tip side at two locations on the outer peripheral side away from the web at the center of the tool body (1A). Two blind holes are provided. As shown in FIGS. 2 and 3, each second branch pipe (9B) opens in the wall surface of each chip discharge groove (4), and the opening (10B) and the tip of the second main pipe (8B). It is drilled as two independent holes that connect the respective parts. Both of these second branch pipes (9B) face the rear end side of the drill (1). Further, the openings (10B) of these second branch pipes are provided at substantially the same position in the axis (O) direction of the drill (1), and are extremely at the tip end side or extreme of the chip discharge groove (4). And is provided at a substantially middle position of the length of the chip discharge groove (4), avoiding the rear end side.

The effects of the throw-away drill (1) having the above configuration will be described below. In deep hole machining, it takes longer for chips to be ejected to the outside of the machined hole, so that the chips must contact the wall of the chip ejection groove (4) and the inner wall of the machined hole. As a result, the frictional resistance is increased, and chip clogging is likely to occur. Further, in the chip discharge groove (4), as the flow rate of the cutting fluid decreases as it approaches the rear end side, the chip discharge speed also decreases. This promotes the problem of chip clogging due to the increase in the frictional resistance described above. It will be. However, in the throw-away drill (1) according to the present embodiment, in addition to the cutting fluid discharged from the first branch pipe (9A), the first part having the opening (10B) on the wall surface of the chip discharge groove (4). A sufficient amount of cutting fluid is supplied to the drill blade and the chip discharge groove (4) by the cutting fluid discharged from the two-branch pipe (9B), and the cutting liquid discharged from the second branch pipe (9B). This prevents a decrease in the flow rate of the cutting fluid on the rear end side of the chip discharge groove (4). Therefore, the frictional resistance caused by the contact of the chips with the wall surface of the chip discharge groove (4) and the inner wall surface of the machining hole is reduced, and the reduction of the chip discharge speed is extremely small, so that the chip clogging is greatly reduced To be prevented. Further, the cutting fluid discharged from the second branch pipe (9B) has a sufficient flow rate and a high flow rate in the cutting fluid flowing in the chip discharge groove (4). Can also be forced out of the hole. From the above, chip dischargeability in deep hole machining is greatly improved. Here, as the deep hole machining capable of obtaining the above effect, a drilling process in which the depth of the machining hole is larger than three times the outer diameter (D) of the drill blade is preferable. A drilling process of 4 times or more the outer diameter (D) is particularly preferable because the above-described effect becomes remarkable.

If the opening (10B) of the second branch pipe is too close to the tip of the drill (1), the flow rate of the cutting fluid decreases on the rear end side of the chip discharge groove (4), so that the chips are forcibly forced. There is a possibility that the effect of discharging may not be obtained, and if the opening (10B) is too close to the rear end of the chip discharging groove (4), chip clogging may occur on the tip side of the opening (10B). There is. Therefore, the opening (10B) is preferably provided at a substantially intermediate position between the tip of the drill (1) and the rear end of the chip discharge groove (4), and more specifically, the drill (1). ) To the opening (10B) is preferably set in the range of 1D to 3D (D: outer diameter of the drill blade), and is preferably set in the range of 1.5D to 3D. Particularly preferred.

As shown in FIG. 6 which is an arrow A view in FIG. 4 and FIG. 7 which is an arrow B view, the axis of the second main pipe (8B) and the second main pipe (8B) opened to the second main pipe (8B). The angle (α1) formed between the axis of the second branch pipe (9B) and the axis (O) of the drill (1) when viewed from the direction perpendicular to each plane passing through the axis of the two branch pipe (9B). , Α2) is too large, a part of the cutting fluid may flow back to the tip side of the drill (1) to reduce chip discharge. On the other hand, if it is too small, the second branch pipe (9B) There is a risk that machining may become impossible due to restrictions and interference of the tool to be machined. Therefore, the angles (α1, α2) are preferably set in the range of 15 ° to 75 °, and particularly preferably set in the range of 30 ° to 60 °.

Next, a throw-away drill according to another embodiment to which the present invention is applied will be described with reference to FIG. FIG. 8 is a front view of the throw-away drill. As can be seen from FIG. 8, the drill (1) is provided with the opening (10B) of the second branch pipe spaced apart at two positions in the axis (O) direction. That is, the drill according to the above-described embodiment assumes that the machining hole depth is 4 to 5 times the outer diameter (D) of the drill blade. (9B) is only provided at one position in the axis (O) direction, the chip clogging on the rear end side of the chip discharge groove (4) is insufficiently improved. The second branch pipe (9B) is drilled at the position so as to open in the wall surface of the chip discharge groove (4). The structure of these 2nd branch pipes (9B) is the same as that of the drill of previous embodiment. Regarding the distance from the tip of the drill (1) to the openings (10B) of these second branch pipes, the distance of the opening (10B) provided on the tip side from the tip of the drill (1) is Like the drill of the embodiment, it is preferably set in the range of 1D to 3D (D: outer diameter of the drill blade), particularly preferably in the range of 1.5D to 3D. The distance from the opening (10B) provided on the front end side to the opening (10B) provided on the rear end side is preferably set in the range of 1D to 3D, particularly preferably in the range of 1.5D to 3D. Is done. Note that the opening (10B) of the second branch pipe may be provided at three or more positions in the axis (O) direction. In this case, the distance between the openings (10B) of the second branch pipes adjacent in the axis (O) direction is preferably set in the range of 1D to 3D, particularly preferably in the range of 1.5D to 3D as described above. Is done.

Although the preferred embodiments of the present invention have been described above, as will be understood by those skilled in the art, additions, changes, substitutions and deletions not specifically described above are performed without departing from the spirit of the present invention. be able to.

1 is a front view of a throw-away drill according to an embodiment of the present invention. It is a top view of the throwaway type drill shown in FIG. FIG. 2 is a bottom view of the throw-away drill shown in FIG. 1. FIG. 2 is a side view of the throwaway drill shown in FIG. It is CC sectional view taken on the line in FIG. It is A arrow directional view in FIG. It is a B arrow line view in FIG. It is a front view of the throw-away drill according to another embodiment. It is a figure which shows the conventional throwaway type drill, (a) is a front view, (b) is a side view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Throw away type drill 1A Tool main body 2 Shank 3 Flange 4 Chip discharge groove 5 Throw away tip 6 Tightening screw 7 Oil hole 7A 1st oil hole 7B 2nd oil hole 8A 1st main pipe 8B 2nd main pipe 9A 1st Branch pipe 9B Second branch pipe 10A First branch pipe opening 10B Second branch pipe opening

Claims (5)

At least one chip discharge groove extends from the front end surface to the rear end side of the tool body along the axis on the outer peripheral surface of the tool body rotated about the axis, In the throw-away drill in which a hole is drilled, the oil hole includes a first oil hole and a second oil hole, and the first oil hole extends from the rear end surface of the tool body to the front end side. A first main pipe drilled along the axis, and a first branch pipe formed by connecting a distal end portion of the first main pipe and an opening portion facing the distal end side of the tool body. The second oil hole includes a second main pipe drilled along the axis from the rear end surface of the tool body toward the front end side, a front end portion of the second main pipe, and the chip discharge groove. A second branch pipe connected to an opening provided on the wall surface, and the second branch pipe faces the rear end side of the drill. , The opening of the second branch pipe, said indexable drill than the opening of the first branch pipe and which are located on the rear end side of the drill. 2. The throw-away drill according to claim 1, wherein the opening of the first branch pipe is provided at a substantially middle position of the whole length of the chip discharge groove in the axial direction. The throw-away type according to claim 1, wherein the distance from the tip of the drill to the opening of the second branch pipe is set in a range of 1D to 3D (D: outer diameter of the drill blade). drill. The said 2nd branch pipe faces the rear-end side of this drill, The angle made with the axis line of this drill is 15 degrees or more and 75 degrees or less, The any one of Claims 1-3 characterized by the above-mentioned. The throw-away drill described. The said 2nd branch pipe faces the rear-end side of this drill, The angle made with the axis line of this drill is 30 degrees or more and 60 degrees or less, The any one of Claims 1-4 characterized by the above-mentioned. The throw-away drill described.

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