JPH0541617U - Drill for lining pipe - Google Patents

Abstract

(57) [Summary] [Purpose] When drilling a lining pipe with an inner surface lining, devise the shape of the drill tip to accelerate the time to start breaking through the lining portion, and at the end of the hole drilling the drill By making it difficult to penetrate, peeling and burring do not occur in the lining portion at the peripheral edge of the through hole. [Structure] The tip angle is set to an acute angle side, and R is attached to the outer peripheral edge of the tip. It also targets straight-edged drills with a rake angle of zero degrees.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a dedicated drill suitable for drilling a lining pipe having an inner surface lined such as an epoxy powder coating pipe or a vinyl chloride lining pipe.

[0002]

[Prior Art]

 Generally, a lining pipe having a lining made of resin or the like on the inner surface of a cast iron pipe or the like has an advantage that the inner wall of the pipe cannot be rusted because the lining portion exhibits a rust preventing function.

[0003]

[Problems to be solved by the device]

 However, when drilling in this lining pipe, the lining part at the peripheral edge of the through hole is pushed by the tip of the drill and stretches, causing peeling (peeling) from the pipe body or burring due to uncut drill. Was seen. When the lining part peels off, the pipe body is rusted and the original purpose of the lining pipe cannot be achieved. Regarding the burrs, it is desirable to carry out secondary processing in order to finish the end cleanly, but at present it is not possible to do secondary processing because it is the inner surface of the pipe.

The present invention has been made paying attention to such a point, and its purpose is to devise the shape of the drill tip to accelerate the time to start breaking through the lining portion and to finish the drilling of the hole. By making it difficult for the drill to penetrate all at once at the stage, it is necessary to prevent peeling and burrs from occurring in the lining part at the peripheral edge of the through hole.

[0005]

[Means for Solving the Problems]

 In order to achieve the above object, the lining pipe drill of claim 1 is intended for a drill for drilling a pipe having an inner surface lined. On the other hand, the tip angle is set to the acute angle side, and R is attached to the outer peripheral edge of the tip. Here, "on the acute angle side" means an angle smaller than about 118 degrees which is usually used for perforating a lining pipe, and the angle also includes about 90 degrees.

Further, the lining pipe drill according to a second aspect of the present invention has a configuration in which the rake angle of the drill according to the first aspect is set to zero to form a straight blade shape.

[0007]

[Action]

 When drilling the lining pipe with the drill for lining pipes according to claim 1, since the tip angle is set to an acute angle side, the time at which the drill tip begins to break through the lining portion is shortened, and cutting with the next cutting edge is promptly performed. Go to the stage. Therefore, the lining portion is not pushed by the tip of the drill and does not extend, so it does not peel off from the pipe body.

Further, since the outer peripheral edge of the drill tip is rounded, the unprocessed portion of the liner pipe remains for a long time at the final stage of through-hole processing, making it difficult for the drill to penetrate all at once and reducing the cutting amount of the drill. Since it is less, the cutting powder becomes finer, and peeling and burrs do not occur on the lining part. Also, if the chips are fine, they are smoothly discharged to the rear of the drill and do not fall to the front of the through hole when the drill penetrates.

According to the lining pipe drill of the second aspect, in addition to the above-mentioned action, since the rake angle is a straight blade type drill having a rake angle of 0 degree, the cutting depth of the drill is set to be small, which makes it difficult for the drill to penetrate all at once. And the action of making the chips finer are promoted.

[0010]

【Example】

 Embodiments of the present invention will be described below. 1 and 2 show a straight blade type drill 10 for a lining pipe according to an embodiment, in which a main body 11, a screw type shank 12 integrally provided at the base end of the main body 11, and a tip end of the main body 11 are provided. The welded cemented carbide tip 13 is provided, and a cutting edge 13a is formed at the side edge of the cemented carbide tip 13, whereby the rake angle is set to zero. A flank 14 is formed on the surface of the cemented carbide tip 13 opposite to the cutting edge 13a.

A feature of the present invention is that the tip angle of the drill 10 is set to 90 degrees. Further, the R portion 15 is formed by performing R processing on the outer peripheral edge of the tip.

Next, to explain the operation of the above-described embodiment, when the lining pipe 20 is drilled with the drill 10, the tip angle is 90 degrees, which is sharper than the normally used angle of 118 degrees. Since the drill tip begins to break through the lining portion 20a at the peripheral edge of the through hole 21, the drill tip moves quickly to the next stage, that is, the cutting stage by the cutting blade. Therefore, since the lining portion 20a is not pushed by the tip of the drill and stretches, the lining portion 20a is not separated from the pipe body.

Further, according to the conventional drill 1 which is not subjected to the R processing as shown in FIG. 6, as shown on the left side of FIG. Will end up. However, according to the drill 10 of the above-described embodiment, since the R portion 15 is formed on the outer peripheral edge of the drill tip, as shown in the right side of FIG. The portion remains long, it requires a longer stroke than the conventional one to penetrate, and the cutting amount of the drill 10 decreases, so the cutting powder becomes finer. Therefore, peeling and burrs do not occur on the lining portion 20a. Further, if the cutting powder is fine, it is smoothly discharged to the rear of the drill 10 and does not fall to the front of the through hole 21 when the drill penetrates. In that case, for example, when the through hole 21 is processed in the existing lining pipe 20 while the fluid is actually being transported, the fluid is ejected to the rear of the drill 10 to promote the discharge of the cutting chips. If the chips are fine as described above, the discharge of the chips by the fluid is performed more effectively.

Moreover, since the drill is a straight-edged drill with a rake angle of zero degrees, the cutting depth of the drill is set to be small, which facilitates the action of making it difficult for the drill to penetrate all at once and the action of making fine chips fine. ..

Further, in the case of a straight-edged drill as in the above embodiment, the planar shape of the tip becomes larger than that of the twist drill, so the drill 10 penetrates at a stretch at the final stage of through-hole processing. It is difficult to prevent peeling and burr from this surface.

4 and 5 show a straight-edged drill 10 according to another embodiment, in which the same parts as those in the previous embodiment are designated by the same reference numerals.

The drill of the present invention targets a lining pipe whose inner surface is lined, such as an epoxy powder coating pipe, a vinyl chloride lining pipe, and a mortar lining pipe.

[0018]

[Effect of the device]

 As described above, in the lining pipe drill of claim 1, the tip angle is set to the acute angle side and R is attached to the outer peripheral edge, so that the time at which the drill tip starts to break through the lining portion is shortened and At the final stage of through-hole processing, the unprocessed part of the lining pipe remains for a long time, making it difficult for the drill to penetrate all at once, and the cutting amount of the drill becomes small and the cutting powder becomes fine, resulting in peeling and burrs on the lining part. In addition, the rust prevention function of the lining pipe can be improved, and the chips are not smoothly discharged to the rear of the drill and fall into the front of the through hole when the drill penetrates.

Further, in claim 2, since the tip angle of the straight-edged drill is set to an acute angle side and R is attached to the outer peripheral edge, the cutting amount of the drill is set to be small and the above-mentioned effect can be obtained more remarkably. Be done.

[Brief description of drawings]

FIG. 1 is a front view of an embodiment,

FIG. 2 is a plan view of the embodiment,

FIG. 3 is a vertical cross-sectional side view comparing an example and a conventional example at the final stage of through hole processing,

FIG. 4 is a front view of another embodiment,

FIG. 5 is a plan view of another embodiment,

FIG. 6 is a front view of a conventional example.

[Explanation of symbols]

 10 Drill 15 R Part 20 Lining Pipe 20a Lining Part 21 Through Hole 1 Conventional Drill

Claims (2)

[Scope of utility model registration request] 1. A lining pipe drill for piercing a lining pipe having an inner surface lined, wherein the tip angle is set to an acute angle side, and R is attached to the outer peripheral edge of the tip. Pipe drill. 2. A drill for a lining pipe according to claim 1, wherein the rake has a straight blade shape having a rake angle of zero degree.