JPS5852009Y2 - Drill - Google Patents

Description

[Detailed description of the invention] This invention relates to a drill that prevents the occurrence of paris.

Conventionally, when drilling with a drill, burrs are generated on the side of the workpiece, which must be removed using a file or a chisel during post-processing.

Particularly in outdoor work using hand polarizers, etc., the workpieces are often extremely large or long, and it is difficult to remove these burrs that form on the back side of the machined hole, making it difficult to develop a drill that does not generate burrs. It was wanted.

As shown in Fig. 1, when the chisel part 1 of the drill penetrates the cutting side of the machining part 2,
The outer periphery of the drill is still being cut, and a portion 3 remains uncut at the exit of the hole.

When the tip of the drill is then completely penetrated, a portion 3 is formed in the paris 4, as shown in FIG.

In order to make this gap as small as possible, drills have traditionally been machined with a large tip angle θ, but increasing the tip angle reduces the centripetality during drilling, resulting in a straight hole in an accurate location. There will be negative effects such as not being able to open it.

On the other hand, in order to completely remove the cracked part 3 into chips by cutting, the cutting edge near the outer periphery must be extremely sharp and have good machinability, but no matter how sharp the relief angle at the tip of the drill is, However, the problem arises that the drill is more likely to become chipped.

The purpose of this invention is to solve these problems. When the outside diameter of the drill is D, it extends from the intersection of the cutting edge that forms the tip angle and the outer circumferential margin to the handle side in a range equal to or less than ID. This invention relates to a drill having an outer circumferential relief angle in an outer circumferential margin.

Next, an embodiment of this invention will be explained with reference to the drawings. As shown in FIGS. 3 and 4, when the outer diameter of the drill is D, the cutting edge 5 and the margin part 6 on the outer periphery forming a tip angle θ Intersection 7
An outer circumferential relief angle 9 is provided in the outer circumferential margin portion over a portion 8 in the range below the ID from the handle side to the handle side.

Conventionally, the outer circumferential margin portion 6 has generally been concentrically shaped, but by providing an outer circumferential relief angle here, the cutting quality of a portion of the corner has been significantly improved, and the occurrence of pars has been almost eliminated.

However, if an angle is provided on the margin of the drill bit over the entire length of the drill bit, similar to the cutting edge of an end mill, the following disadvantages will occur.

In other words, during drilling, a thrust load is constantly applied in the axial direction of the drill, so the drill can be held almost vertically as shown by a in Figure 5, but at the moment the drill penetrates the workpiece. causes the worker to lose balance, b
, or C, the axis of the hole drilled in the workpiece cannot be maintained.

At this time, if a relief angle is provided on the outer peripheral margin of the drill, the side surface of the drilled hole may have to be cut again, and a large cutting torque is applied to the drill, causing the hand polar to rotate or This may cause defects such as breakage.

However, in this invention, as shown in FIG. 4, the outer peripheral clearance angle 9 is provided in the outer peripheral margin only in the range 8 below about ID from the corner of the tip, so that the cutting quality of the outer peripheral part of the cutting blade can be improved, and Immediately after penetration by the no-do borer, the drill has already advanced to the margin part 10 where there is no clearance angle on the outer periphery, so even if the axis of the machined hole and the axis of the drill do not match slightly and become unstable, the side surface of the machined hole can be maintained. Since the drill is not cut, there is no chance of the drill breaking, the band polarizer rotating, or the operator being turned.

Another reason for providing an outer peripheral relief angle only in the range below ID from the tip corner is to facilitate re-grinding from the tip, and the length of one re-grinding is set to 0. If you do it one by one, you can do it about 10 times, so the minimum range is one tooth feed per rotation of the drill, or 0.1 to 0.3.
It is desirable that the thickness be about mm or more.

In order to control the diameter of the drill during the grinding process to create a bending angle on the outer periphery, as shown in Figure 6, the round land portion 11 may be left in a range of 0.1 mm or less; This has little effect on the outbreak of Paris.

[Brief explanation of the drawing]

Figures 1 and 2 are explanatory diagrams of the cutting situation with a drill. Figure 1 shows the state in which the chisel part has penetrated to the extraction side, and Figure 2 shows the state in which the entire tip of the drill has penetrated completely. Figure 3 is a side view of an embodiment of this invention, Figure 4 is an enlarged perspective view of the tip of the drill, Figure 5 is an explanatory diagram of the cutting principle of the drill, and Figure 6 is the tip of another embodiment. It is a sectional view of the main part. 5... Cutting edge ridge, 6... Outer circumference margin, 7... Intersection, 8... Range below ID, 9... Relief angle, θ...
・Tip angle.

Claims (1)

[Scope of utility model registration request] When the outer diameter of the drill is D, a drill has an outer circumferential clearance angle in the outer circumferential margin part extending from the intersection of the cutting edge ridge forming the tip angle and the outer circumferential margin part to the handle side in a range equal to or less than ID.