JP2788148B2 - Drill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber reinforced plastic (FRP) using a reinforcing material such as glass fiber or carbon fiber.
The present invention relates to a drill which is most suitable for drilling a composite material such as.

[0002]

2. Description of the Related Art Conventionally, when drilling a composite material of this type using a normal drill, it is not possible to sufficiently cut glass fiber and the like, and burrs are particularly generated at the entrance and exit of the drilled hole. Remaining, it was not possible to obtain a beautiful processed surface.

[0003]

For this reason, when a conventional drill is used, a finishing process for removing burrs and the like after drilling is required. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a drill that can prevent generation of burrs when drilling a composite material such as FRP.

[0004]

In order to achieve the above object, the present invention has a pair of outer peripheral blades which extend obliquely inward from the outer periphery of the distal end of the drill body toward the base end in the axial direction,
A leading edge protruding from the inner end of each of the outer peripheral edges toward the axial center is formed, and in a drill formed by the pair of outer peripheral blades and the preceding blade, the leading edge angle of the preceding blade is 20 °. And the angle between the outer peripheral edge and the direction perpendicular to the axis is formed in the range of 10 ° to 20 °, and the core thickness of the drill body is set to 10 mm of the diameter of the drill body.
% To 20%, and the leading end of the preceding blade is positioned such that the leading end is located closer to the distal end in the axial direction than the outer peripheral end of the outer peripheral blade, and the step in the axial direction between the leading end of the preceding blade and the outer peripheral end of the outer peripheral blade is reduced. The drill body is formed to have a diameter of 25% to 30% of the diameter of the drill body.

The reason why the tip angle is set to 20 ° to 40 ° as described above is that when the tip angle is less than 20 °, the cutting force acting in the direction perpendicular to the preceding blade becomes large. Because, it becomes possible to cut glass fiber and the like neatly, but since the leading blade has a sharply pointed shape on the tip side, it is easy to cause cutting edge breakage especially at the start of processing of a hole or at the time of penetration. When the angle exceeds 40 °, the cutting force decreases, and the pushing force acting in the axial direction increases. Therefore, it becomes difficult to cut glass fibers and the like, and burrs are formed particularly at the entrance and exit of the processing hole. This is because it easily occurs.

Further, the angle between the outer peripheral edge and the direction perpendicular to the axis is formed in the range of 10 ° to 20 °. If the angle is less than 10 °, the cutting force acting at right angles to the outer peripheral edge is reduced. In addition, since the pushing force acting in the axial direction increases, it becomes difficult to cut glass fibers and the like, and burrs are easily generated particularly at the entrance and exit of the processing hole. This is because the cutting force is increased and glass fibers and the like can be cut neatly, but the cutting edge protrudes sharply to the tip side, so that the cutting edge is likely to be broken. Further, the reason why the core thickness is formed to be 10% to 20% of the diameter of the drill body is that when the core thickness is formed to be less than 10%, the pushing force is reduced, but the strength of the drill body is insufficient and the drill body is easily broken. If it exceeds 20%, the pushing force increases and burrs are likely to be generated at the entrance and exit of the processing hole.

Further, the step in the axial direction between the leading end of the leading blade and the outer peripheral end of the outer peripheral blade is set at 25% or less of the diameter of the drill body.
The reason why the cutting edge is formed at 30% is that if it is less than 25%, the cutting edge length of the outer cutting edge becomes longer, that is, the position of the inner end of the outer cutting edge is positioned on the axis side, so that the sharpness of this portion is improved. This increases the indentation force, causing elastic deformation of the FRP, making it difficult to cut by the outer peripheral blade, and leaving burrs at the entrance and exit of the processing hole.
If it exceeds 0%, the length of the cutting edge of the preceding blade becomes longer, and the unstable time until the outer peripheral blade starts cutting becomes longer, thereby causing burrs at the entrance and exit to easily occur. In addition, when it exceeds 30%, there is also a disadvantage that the cutting time is reduced by only the leading blade, so that the leading blade is easily broken.

[0008]

According to the present invention, first, cutting is started with the preceding blade. Since the leading edge is formed at a tip angle of 20 ° to 40 ° and the cutting force acting on the leading blade is large, cutting of glass fiber or the like is performed neatly even at the axial position of the drill body. . Next, cutting by the outer peripheral edge of the outer peripheral blade is started. In this case, since the drill main body is supported by the preceding blade, the cutting by the outer peripheral blade is stably started. And, since the angle between the outer peripheral blade and the direction perpendicular to the axis is formed in the range of 10 ° to 20 °, the cutting force acting on the outer peripheral blade is large. It is cut neatly. Furthermore, since the step in the axial direction between the tip of the preceding blade and the outer peripheral end of the outer peripheral blade is formed at 25% to 30% of the diameter of the drill main body, the inner end of the outer peripheral blade is sufficiently positioned more than the axial center position of the drill main body. It can be located on the outer peripheral side, and the pushing force of this portion is reduced. For this reason, even with a material such as FRP, deformation due to the indentation force is suppressed to a small extent, and in particular, cutting of glass fibers or the like by the outer peripheral blade can be easily performed. Therefore, it is possible to reduce the burrs at the entrance and exit of the machined hole when drilling a composite material such as FRP.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In these figures, reference numeral 1 denotes a drill body formed of a cemented carbide, and two grooves 2 having a constant twist angle are formed on the outer periphery of the drill body 1. A tip cutting edge 3 is formed at the tip of each groove 2. The distal cutting edge 3 extends inward from an outer peripheral end 4a and extends obliquely toward a base end side in the axial direction, and an inner peripheral end 4b of the outer peripheral blade 4 extends in an axial direction from an inner end 4b. Is formed by the leading blade 5 protruding toward the distal end side of the front end. The leading edges 5a of the leading blades 5 intersect at one point. The distal end surfaces of the outer peripheral blades 4 and the leading blades 5 in the anti-rotation direction are the outer peripheral blade flank surfaces 6 and the leading blade flank surfaces 7.

The outer peripheral blade 4 and the leading blade 5 are formed linearly in a side view as shown in FIG. 1, and their crossing angle is formed at 90 ° in this embodiment. Also,
The angle α formed between the outer peripheral blade 4 and the direction orthogonal to the axis C of the drill body 1 is formed at 10 ° to 20 °, the tip angle β formed by the leading blade 5 is formed at 20 ° to 40 °, and the leading blade 5 is formed. A step G in the axial direction between the tip 5a of the drill body and the outer peripheral end 4a of the outer peripheral blade 4 is formed at 25% to 30% of the diameter of the drill body 1, and the core thickness of the drill body 1 (see FIG. 2) is determined. It is formed to 10% to 20% of one diameter.

Next, the operation of the drill configured as described above will be described. When drilling a hole in an FRP using glass fiber as a reinforcing material with this drill, first,
Cutting is started by the leading blade 5. Since the leading edge of the leading blade 5 is formed at an angle of 20 ° to 40 °, the cutting force acting on the leading blade 5 in a direction perpendicular to the leading edge 5 is large. For this reason, even if it is in the axis C of the drill main body 1, cutting of glass fiber etc. is performed neatly. That is, the occurrence of burrs at the axial center of the drill is suppressed. By further pushing the drill, the outer peripheral edge 4
Cutting by a is started. In this case, since the drill body 1 is supported by the preceding blade 5, cutting by the outer peripheral blade 4 is stably performed. Since the angle α between the outer peripheral blade 4 and the direction perpendicular to the axis is formed in the range of 10 ° to 20 °, the cutting force acting on the outer peripheral blade 4 at a right angle is large. At the end 4a, glass fibers and the like are cut finely. Further, the tip 5 of the leading blade 5
a and the outer peripheral edge 4 a of the outer peripheral edge 4 have a step G in the axial direction of 25% to 30% of the diameter of the drill body 1, so that the inner end 4 b of the outer peripheral edge 1 is positioned from the axis of the drill body 1. It can be located sufficiently on the outer peripheral side. That is, since the cutting speed at the inner end 4b is sufficiently high, the pushing force at this portion is reduced. For this reason, even when a hole is formed in a material such as FRP, the deformation generated in the FRP due to the pushing force can be suppressed to a small value, and therefore, particularly, the cutting of the glass fiber or the like by the outer peripheral edge becomes easy.

Therefore, according to the drill configured as described above, it is possible to prevent the occurrence of burrs at the entrance / exit of the machined hole when drilling a composite material such as FRP. In the above embodiment, the angle between the outer peripheral blade 4 and the leading blade 5 is set to 90 °, but it is needless to say that the angle is not limited to this angle.

[0013]

As described above, according to the present invention, a pair of outer peripheral blades are formed which extend obliquely inward from the outer periphery of the distal end of the drill body toward the base end in the axial direction. A leading edge protruding toward the distal end side from the one end toward the axis is formed, and in a drill in which the leading edge cutting edge is formed by the pair of outer peripheral blade and the leading edge, the leading edge angle of the preceding blade is 20 ° to 40 °. And the angle between the outer peripheral edge and the direction perpendicular to the axis is formed at 10 ° to 20 °, and the core thickness of the drill body is 10% to 2% of the diameter of the drill body.
0%, and the leading end of the preceding blade is positioned on the distal end side in the axial direction from the outer peripheral end of the outer peripheral blade, and the step in the axial direction between the leading end of the preceding blade and the outer peripheral end of the outer peripheral blade is adjusted by the drill body. Since it is formed to have a diameter of 25% to 30%, the cutting force acting at right angles to the cutting edge becomes large and the pushing force becomes small over the entire cutting edge. Therefore, the glass fiber or the like can be cut neatly, and the occurrence of burrs in the processed hole can be prevented.

[Brief description of the drawings]

FIG. 1 is a view taken in the direction of the arrow I in FIG. 2;

FIG. 2 is a top view of one embodiment of a drill.

FIG. 3 is a view taken in the direction of the arrow III in FIG. 1;

FIG. 4 is a view taken in the direction of the arrow IV in FIG. 2;

FIG. 5 is a view taken in the direction of the arrow V in FIG. 2;

FIG. 6 is a side view of the drill.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drill main body 3 Tip cutting edge 4 Outer edge 4a Outer edge 4b Inner end 5 Leading edge 5a Tip C Axis W Core thickness α Angle between the outer edge and a direction perpendicular to the axis β Tip angle

Continuing on the front page (72) Inventor Kouji Hashimoto 10th Oecho, Minato-ku, Nagoya City, Aichi Prefecture Mitsubishi Heavy Industries, Ltd.Nagoya Aerospace System Works (72) Inventor Shinichi Nakamura No. 1528 Mitsubishi Materials Corporation Gifu Works (72) Inventor Kazuo Takasaki Gibe Prefecture Anpachi-gun Kobe-cho Oji-cho Yokoi 1528 Mitsubishi Materials Corporation Gifu Works (72) Inventor Hideji Hosono Anpachi Gifu Prefecture 1528 Nakashinda, Yokoi, Kobe-cho, Gunma Mitsubishi Materials Corporation Gifu Works (72) Inventor Hiroshi Kasuya 2--22-18 Higashisakura, Naka-ku, Nagoya-shi, Aichi Mitsubishi Materials Corporation Nagoya Branch (56) Reference Document JP-A-3-117507 (JP, A) JP-A-1-140908 (JP, A) JP-A 64-44102 (JP, U) JP-A 55-11898 (JP, U) JP-A 56-44 33111 (JP, U) (58) Field surveyed (Int.Cl. ⁶ , DB name) B23B 51/00

Claims (1)

(57) [Claims] 1. A pair of outer peripheral blades extending obliquely inward from an outer periphery of a distal end of a drill body toward an axially proximal end thereof are formed. In a drill in which a protruding leading edge is formed, and a tip cutting edge is formed by the pair of outer peripheral blade and the leading blade, a leading angle formed by the preceding blade is formed at 20 ° to 40 °,
An angle between the outer peripheral edge and a direction perpendicular to the axis is formed at 10 ° to 20 °, a core thickness of the drill body is formed at 10% to 20% of a diameter of the drill body, and a tip of the preceding blade is formed. Is located axially forward from the outer peripheral end of the outer peripheral blade, and the step in the axial direction between the distal end of the preceding blade and the outer peripheral end of the outer peripheral blade is formed at 25% to 30% of the diameter of the drill body. A drill characterized in that: