JP2004167645A - Drill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drill which can improve the roughness of the finished surface of a machined workpiece and its cylindricity and has an edge strengthened to lengthen its service life. <P>SOLUTION: The drill has a cutting blade mounted at the tip of a drill head. A cutting edge 3 having, as a starting point A, a region located outside the outer peripheral surface 1a of the drill head 1 at a position of the maximum radius R from the rotation axis center O of the drill D2 and extending from it to shorten the radius from the center O in the drill rotation direction is formed on the outer peripheral side of the edge of the cutting blade 2. Main cutting is conducted by a first cutting edge corner K1 formed at the end B of the cutting edge 3, and the cutting or compression of a part remaining uncut is conducted by a second edge corner K2 formed at the starting point A of the cutting edge 3. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a drill used for deep hole cutting and the like.
[0002]
[Prior art]
This type of drill has a cutting blade attached to the tip of a drill head. Conventional drills can not be specifically cited in the known literature, but the outer peripheral edge of the cutting edge of the cutting blade is located outside the outer peripheral surface of the drill head and at the position of the maximum radius from the rotation axis of the drill. Therefore, a cutting is performed at the outer peripheral edge, and usually, a chip breaker is formed on the side of the outer peripheral edge of the cutting edge in the drill rotation direction, and the counter rotation of the drill at the outer peripheral edge of the cutting edge is normally performed. On the direction side, a margin portion having the same radius as the radius of the outer peripheral edge of the cutting edge from the rotation axis is formed.
[0003]
[Problems to be solved by the invention]
The drill with the above structure cuts the workpiece only at the outer peripheral edge of the cutting edge located at the maximum radius position from the rotation axis of the drill. In this case, a peak-and-valley shape (sawtooth shape) was formed, and the finished surface roughness and cylindricity of the workpiece did not increase, making it very difficult to perform high-precision cutting.
[0004]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a drill capable of improving the finished surface roughness of a workpiece and its cylindricity, and having a strong cutting edge and extending a service life. And
[0005]
[Problems to be solved by the invention]
The invention according to claim 1 is a drill in which a cutting blade is attached to a tip end portion of a drill head, and the drills D1 to D4 are provided on the outer peripheral side of the cutting edge of the cutting blade 2 outside the outer peripheral surface 1a of the drill head 1. The starting point A is a portion located at the position of the maximum radius R from the rotation axis O, and a cutting edge 3 extending linearly or arcuately so as to reduce the radius from the rotation axis O in the drill rotation direction. Then, the main cutting is performed at the first cutting edge corner portion K1 formed at the end point B of the cutting edge portion 3, and the uncut portion is left uncut at the second cutting edge corner portion K2 formed at the starting point A of the cutting edge portion 3. It is characterized in that a part is cut or compressed.
[0006]
Claim 2 has the same radius R as the distance from the rotation axis O to the start point A on the counter-rotation direction side of the drill from the start point A of the cutting edge portion 3 in the drill according to claim 1. It is characterized in that a margin portion 4 is formed.
[0007]
According to a third aspect, in the drill according to the first aspect, a chip breaker 6 is formed on the drill rotation direction side of the end point B of the cutting edge portion 3.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
1A is a side view showing a main part of a drill D1 according to the present invention, FIG. 1B is a plan view thereof, and FIG. 2 is an enlarged view of a portion indicated by an arrow A in FIG. In the figure, reference numeral 1 denotes a drill head of a drill D1, and a cutting blade 2 is fixed to a tip of the drill head 1. GP is a drill guide pad fixed to the outer surface of the tip of the drill head 1, O indicates the rotation axis of the drill D1, and H indicates the rotation direction of the drill D1.
[0009]
The cutting blade 2 is located outside the outer peripheral surface 1a of the drill head 1 on the outer peripheral side of the cutting edge portion, as shown in FIG. A cutting edge portion 3 is formed which extends linearly from the starting point A to the drill rotation direction H so as to reduce the radius R from the rotation axis O from the starting point A at a position located at the radius R. A margin portion 4 having the same radius R as the distance from the rotation axis O to the portion of the starting point A is formed on the rotation direction side of the drill D1 from the starting point A of the cutting edge 3, and formed at the end point B of the cutting edge portion 3. The main cutting is performed by the first cutting edge corner portion K1 to be performed, and the uncut portion is cut or compressed by the second cutting edge corner portion K2 formed at the starting point A of the cutting edge portion 3. . Here, the cutting edge portion 3 is formed in a linear shape, but may be formed in an arc shape.
[0010]
The outer end face 5 of the cutting edge located at the end point B of the cutting edge 3 of the cutting blade 2 is arranged so as to be located substantially parallel to the line extending in the radial direction from the rotation axis O of the drill D1, that is, the radius line. Is established. Accordingly, the angle α of the first cutting edge corner K1 formed at the end point B of the cutting edge 3 is approximately 90 °.
[0011]
In the drill D1 of this embodiment, as shown in FIG. 2, the circumferential length η of the margin portion 4 is 0.2 to 1.2 mm, and the cutting edge portion 3 formed on the front side of the margin portion 4. Has a length δ of 0.4 mm to 0.5 mm. The angle (cutting edge angle) θ formed by the extension line m of the line connecting both ends of the margin portion 4 and the extension line n of the line connecting the start point A and the end point B of the cutting edge portion 3 is 30 ′ to 10 °. The distance γ between the end point B of the cutting edge portion 3 and the extension line m of the line connecting both ends of the margin portion 4 is 0.005 mm to 0.10 mm.
[0012]
Next, the operation of the cutting blade 2 having the above-described cutting edge portion 3 will be described. In cutting a workpiece, main cutting is performed by a first cutting edge corner portion K1 formed at an end point B of the cutting edge portion 3. And the second cutting edge corner portion K2 formed at the starting point A of the cutting edge portion 3 cuts or compresses the uncut portion. First, the first cutting edge corner portion K1 formed at the end point B of the cutting edge portion 3 located at a position smaller than the maximum radius R from the rotation axis O of the drill D1 cuts off and starts cutting. The cutting (main cutting) is performed up to the starting point A of the cutting edge portion 3 at the position of the maximum radius R from the rotation axis O, and the cut surface has a peak and valley (a peak like a saw tooth). (A continuous valley) is generated. However, this peak and valley is subjected to a cutting action or a pressing action by the second cutting edge corner portion K2 formed at the starting point A of the cutting edge portion 3, and has a polished smooth surface (burnish face). , Whereby the surface roughness of the surface to be cut becomes extremely good.
[0013]
Further, in the cutting blade 2, a margin portion 4 having the same radius as the distance from the rotation axis O of the drill D1 to the portion of the start point A is formed on the rotation direction side of the drill D1 from the start point A of the cutting edge portion 3. Therefore, the cutting action or the press-fitting action by the second cutting edge corner portion K2 effectively works in the margin portion 4, and the cut surface becomes more smooth, and the surface roughness is further improved.
[0014]
Moreover, according to the cutting blade 2 having such a cutting edge portion 3, as described above, the cutting edge portion 3 is formed at the end point B of the cutting edge portion 3 located at a radius position smaller than the maximum radius R from the rotation axis O of the drill D1. Since the main cutting is performed by the first cutting edge corner portion K1, the cutting edge portion is less likely to be crushed, that is, the cutting edge portion is strengthened, and the service life can be extended.
[0015]
FIG. 3 shows a drill D2 to which a cutting blade 2 having a chip breaker 6 formed on the drill rotation direction side from an end point B of the cutting blade portion 3 is attached, (A) is a plan view of the drill D2, and (B) is ( It is an enlarged view of the part shown by arrow B of A). As can be seen from FIG. 3B, the cutting blade 2 attached to the drill D2 has, as a starting point A, a part located at the position of the maximum radius R from the rotation axis O of the drill D2 on the outer peripheral side of the cutting edge. Thus, a cutting edge portion 3 extending linearly or in an arc shape is formed so as to reduce the radius R from the rotation axis O in the drill rotation direction H, and the drill D2 is rotated counterclockwise from the starting point A of the cutting edge portion 3. The same as the drill D1 in that a margin portion 4 having the same radius R as the distance from the rotation axis O to the start point A is formed on the direction side, the rotation direction side of the drill D2 from the end point B of the cutting edge portion 3. In that a chip breaker 6 is formed.
[0016]
Also, as for the action of the cutting blade 2, as in the case of the drill D <b> 1, the main cutting is performed by the first cutting edge corner K <b> 1 formed at the end point B of the cutting blade 3 and formed at the starting point A of the cutting blade 3. The cutting or compression of the uncut portion is performed by the second cutting edge corner K2 which is performed. However, since the chip breaker 6 is provided, the cutting waste cut at the first cutting edge corner K1 is provided. Is curled to a small radius and cut into a suitable length, so that the cutting chips can be easily discharged, which is suitable for a ductile material. Since the specific operation of the cutting edge 3 is the same as that of the above-described drill D1, the description thereof is omitted.
[0017]
1 to 3 show the drills D1 and D2 in which the cutting blade 2 is integrally attached to the tip of the drill head 1, but in FIG. 3 shows a drill D3 with a throw-away cutting blade 2 mounted so as to be possible. 4A is a side view showing a main part of the drill D3, FIG. 4B is a plan view thereof, and FIG. 5 is an enlarged view of a portion indicated by an arrow C in FIG. The cutting edge 2 is attached to the drill D3 along the radial line of the drill head 1 on the rotation axis O side and the outer peripheral side thereof. The cutting blade 2 is provided on the outer peripheral side.
[0018]
As can be seen from FIG. 5, the cutting blade 2 is located on the outer peripheral side of the cutting edge portion at a position outside the outer peripheral surface 1a of the drill head 1 and at the maximum radius from the rotation axis O of the drill D3 (see FIG. 4). A starting point A is defined as a starting point A, and a cutting edge 3 extending linearly or in an arc shape is formed so as to reduce a radius from the rotation axis O in the drill rotation direction H from the starting point A, and an end point of the cutting edge 3 is formed. A chip breaker 6 is formed on the rotation direction side of the drill D3 with respect to B. The main cutting is performed by a first cutting edge corner K1 formed at the end point B of the cutting edge 3 as in the case of the drills D1 and D2. The second cutting edge corner K2 formed at the starting point A of the cutting edge 3 cuts or compresses the uncut portion. The cutting blade 2 is not provided with a margin portion 4.
[0019]
6 is an overall side view of a drill D4 used for cutting a hole having a relatively small diameter. FIG. 7A is a plan view, and FIG. 7B is an enlarged side view of a drill head 1 portion. As can be seen from FIGS. 7A and 7B, the cutting blade 2 attached to the drill head 1 has a maximum radius from the rotation axis O of the drill D 4 outside the outer peripheral surface 1 a of the drill head 1. Is formed as a starting point A to form a cutting edge 3 extending linearly or in an arc shape so as to reduce the radius from the rotation axis O in the drill rotation direction H from this point. On the side opposite to the rotation direction of the drill D4 from the start point A, a margin portion 4 having the same radius as the radius R of the start point A portion from the rotation axis O is formed. As in the case of the drills D1 to D3, The main cutting is performed by the first cutting edge corner K1 formed at the end point B of the cutting edge 3, and the uncut portion is cut or cut by the second cutting edge corner K2 formed at the starting point A of the cutting edge 3. Compression is performed.
[0020]
【The invention's effect】
The drill according to the first aspect of the present invention is arranged such that, on the outer peripheral side of the cutting edge of the cutting blade, a portion located outside the outer peripheral surface of the drill head and located at the position of the maximum radius from the rotation axis of the drill is a starting point, and the drill is rotated in the direction of rotation. Forming a cutting edge extending linearly or in an arc so as to reduce the radius from the rotation axis, causing the main cutting to be performed at a first cutting edge corner formed at the end point of the cutting edge; Since the uncut portion is cut or compressed at the second cutting edge corner portion formed at the starting point of the cutting edge portion, first, the maximum to the workpiece portion from the rotation axis of the drill is set. The first cutting edge corner portion formed at the end point B of the cutting edge portion located at a radius position smaller than the radius cuts and starts cutting, and this cutting is performed from the rotation axis to the start point of the cutting edge portion at the maximum radius position. However, peak and A ray (a shape in which peaks and valleys are continuous like a saw tooth) is generated, and this peak and valley becomes a smooth surface due to a cutting action or a crimping action by the second cutting edge corner portion. The surface roughness of the surface to be cut can be improved.
[0021]
Further, as described above, the main cutting is performed by the first cutting edge corner formed at the end point of the cutting edge located at a radius position smaller than the maximum radius from the rotation axis of the drill, so that the blade tip is less likely to be crushed. In other words, the blade edge is strengthened, and the service life can be extended.
[0022]
According to the drill of the invention according to claim 2, by forming a margin portion having the same radius as the distance from the rotation axis to the start point on the drill rotation direction rear end side from the start point of the cutting edge portion, The cutting action or the press-fitting action by the second cutting edge corner portion works effectively in the margin portion, and the surface to be cut becomes more smooth, and the surface roughness is further improved.
[0023]
According to the drill of the invention according to claim 3, the chip breaker formed at the first cutting edge corner is curled to a small radius by forming the chip breaker on the drill rotation direction side from the end point of the cutting edge. And cut into appropriate lengths, the discharge of cuttings is improved, and this is suitable for ductile materials.
[Brief description of the drawings]
FIG. 1A is a side view showing a main part of a drill according to the present invention, and FIG. 1B is a plan view thereof.
FIG. 2 is an enlarged view of a portion indicated by an arrow A in FIG.
FIG. 3 is a plan view of a drill provided with a cutting blade having a chip breaker formed on the tip side in the drill rotation direction from the end point of the cutting blade, and FIG. 3B is an enlarged view of a portion indicated by an arrow B in FIG.
FIG. 4 (A) is a side view showing a main part of a drill having a throwaway cutting blade, and FIG. 4 (B) is a plan view thereof.
FIG. 5 is an enlarged view of a portion indicated by an arrow C in FIG.
FIG. 6 is an overall side view of a drill used for cutting a relatively small diameter hole.
7A is a plan view of the drill shown in FIG. 6, and FIG. 7B is an enlarged side view of a drill head portion.
[Explanation of symbols]
D1 to D4 Drill O Drill rotation axis 1 Drill head 2 Cutting blade 3 Cutting blade A Starting point B of cutting blade End K1 of cutting blade K1 First cutting blade corner K2 Second cutting blade corner 4 Margin 6 Chip breaker

Claims (3)

In a drill in which a cutting blade is attached to the tip of the drill head, the starting point is located on the outer peripheral side of the cutting edge of the cutting blade, outside the outer peripheral surface of the drill head and located at the maximum radius position from the rotation axis of the drill. A cutting edge portion extending linearly or arcuately so as to reduce the radius from the rotation axis in the drill rotation direction is formed from the first cutting edge corner portion formed at the end point of the cutting edge portion. A drill for performing main cutting and cutting or compressing the uncut portion at a second cutting edge corner formed at the starting point of the cutting edge. 2. The drill according to claim 1, wherein a margin portion having a radius equal to a distance from the rotation axis to a start point portion is formed on a side of the drill in a direction opposite to a rotation direction from a start point of the cutting blade portion. 3. The drill according to claim 1, wherein a chip breaker is formed on the drill rotation direction side of an end point of the cutting edge portion.

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