JP4449355B2 - Drill - Google Patents

Description

【００２６】
表１に示されるように、従来例ではステップ量が０．５ｍｍまでしか加工できなかったのに対し、実施例１ではステップ量が１．０ｍｍまで、実施例２ではステップ量が１．２ｍｍまで、さらに、実施例３ではステップ量が１．５ｍｍまで、切屑詰まりを生じさせることなく安定した穴明け加工を継続することができており、本発明の一例である実施例１〜３が、従来例よりも格段に優れていることが分かる。
【００２７】
【発明の効果】
本発明によれば、刃先部を先端側から見たときに、切屑排出溝の溝底を構成する壁面と先端逃げ面との交差稜線部が、上述した交点よりも軸線寄りに位置させられているため、従来のドリルと同一の心厚を有していながらも、チゼルエッジにて生成される切屑を排出する切屑排出溝のスペースを大きくすることが可能となっている。
したがって、刃先部の先端を大きく切り欠いてシンニングや副溝を形成して刃先部の剛性を低めなくても、チゼルエッジにて生成される切屑の排出性を改善することができ、これにともない、切屑詰まりの発生を抑制することができる。さらに、本発明のドリルは、切屑排出溝の溝底の位置が従来のドリルとは異なっているものの、従来と同様の切屑排出溝の形成方法で適切な形状を得ることができるため、容易に製造することができる。
【図面の簡単な説明】
【図１】 （ａ）は本発明の第一実施形態によるドリルの刃先部を示す先端面図、（ｂ）は（ａ）におけるＸ部拡大図である。
【図２】 （ａ）は本発明の第二実施形態によるドリルの刃先部を示す先端面図、（ｂ）は（ａ）におけるＸ部拡大図である。
【図３】 本発明の第三実施形態によるドリルの刃先部を示す先端面図である。
【図４】 （ａ）は従来のドリルの刃先部を示す先端面図、（ｂ）は（ａ）におけるＸ部拡大図である。
【符号の説明】
１０ 刃先部
１１ 先端逃げ面
１２ 切屑排出溝
１２Ａ ドリル回転方向前方側を向く壁面
１２Ｂ ドリル回転方向後方側を向く壁面
１２Ｃ 溝底を構成する壁面
１３ 切刃
１４ チゼルエッジ
Ｓ１ 切刃の延長線
Ｓ２ 切刃の延長線に直交して軸線を通る直線
Ｐ 交点
Ｏ 軸線
Ｔ ドリル回転方向[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drill used for drilling for forming a machining hole in a work material, and more particularly to a small diameter drill used for drilling for forming a small-diameter machining hole.
[0002]
[Prior art]
In general, as shown in FIG. 4 (a), the outer periphery of the cutting edge portion 1 which is the tip side portion of the drill body rotated about the axis O is opened to the tip flank 1A of the cutting edge portion 1 and the rear end. A pair of chip discharge grooves 2, 2 extending toward the side are formed, and a pair is formed at the crossing ridge line portion between the wall surfaces 2A, 2A facing the front side in the drill rotation direction of the pair of chip discharge grooves 2, 2 and the tip flank 1A. There is known a drill in which a chisel edge 4 that connects inner peripheral ends of a pair of cutting blades 3 and 3 is formed on the tip flank 1A.
[0003]
In such a drill, when the cutting edge portion 1 is viewed from the tip end side in the direction of the axis O, as shown in FIG. 4B which is an enlarged view of the main part of FIG. The intersecting ridge line portion between the wall surface 2B constituting the groove bottom and the tip flank 1A is closer to the axis O than the intersection point P between the extension line S1 of the cutting edge 3 and the straight line S2 orthogonal to the extension line S1. Since it is located so that it may leave | separate, it is inferior to the discharge property of the chip | tip produced | generated in the chisel edge 4, and there exists a problem that it is easy to produce a chip clog.
In order to solve this problem, various proposals have been made conventionally. For example, Patent Document 1 discloses a drill in which a so-called X-shaped thinning is added to a chisel edge formed on a tip clearance surface. Patent Document 2 discloses a drill in which a sub-groove for discharging chips generated at a chisel edge is additionally formed in addition to a normal chip discharge groove.
[0004]
[Patent Document 1]
Japanese Utility Model Publication No. 60-40259 [Patent Document 2]
Japanese Patent Laid-Open No. 60-25608
[Problems to be solved by the invention]
However, in the drills disclosed in Patent Document 1 and Patent Document 2, the chip discharging property can be improved, but the thinning and the auxiliary groove are additionally processed so that the tip of the blade edge portion is greatly cut out. For this reason, the rigidity of the cutting edge portion is remarkably lowered, and the drill itself is not easily manufactured due to the necessity of thinning or additional machining of the sub-groove. In particular, such a tendency becomes conspicuous in a small-diameter drill used for drilling for forming a small-diameter machining hole in a work material.
The present invention has been made in view of the above problems, and suppresses the occurrence of chip clogging while maintaining good dischargeability of chips generated at the chisel edge without inadvertently reducing the rigidity of the cutting edge. An object of the present invention is to provide a drill that can be manufactured and is easy to manufacture.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problems and achieve such an object, the drill of the present invention is provided on the outer periphery of the cutting edge part, which is the tip side part of the drill body rotated about the axis, on the outer periphery of the cutting edge part. A drill in which a chip discharge groove is formed that opens to the surface and extends toward the rear end side, and a cutting edge is formed at a cross ridge line portion between the wall surface facing the front side in the drill rotation direction of the chip discharge groove and the tip flank surface The outer diameter of the cutting blade is set in a range of 0.05 mm to 2.00 mm, and the bottom of the chip discharge groove when the cutting edge portion is viewed from the tip end side in the axial direction. The intersecting ridge line portion between the wall surface and the tip flank is positioned closer to the axis than the intersection of the extension line of the cutting edge and a straight line passing through the axis and orthogonal to the extension line. It is characterized by.
[0007]
According to such a drill of the present invention, when the cutting edge portion is viewed from the tip side, the intersecting ridge line portion between the wall surface constituting the groove bottom of the chip discharge groove and the tip flank surface is closer to the axis than the above intersection. Therefore, even if it has the same core thickness as the cutting edge of a conventional drill, chips generated at the chisel edge formed on the tip flank of the cutting edge are discharged. It is possible to secure a large space for this.
Therefore, it is possible to improve the discharge of chips generated at the chisel edge without reducing the rigidity of the blade tip portion by forming a thinning or sub-groove by notching the tip of the blade tip portion greatly. The occurrence of chip clogging can be suppressed. Furthermore, although the position of the groove bottom of the chip discharge groove is different from that of the conventional drill, the drill of the present invention can easily obtain an appropriate shape by the same method of forming the chip discharge groove as before. Can be manufactured.
[0008]
Further, in the drill of the present invention, the tip flank may be a multi-stage surface composed of a plurality of flank, and with such a configuration, the flow of chips generated at the chisel edge It is improved and the chip discharge performance can be further improved, and the tip of the cutting edge part is not greatly cut out like thinning and sub-grooves, so the rigidity of the cutting edge part is lowered carelessly. There is no such thing.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
First, it demonstrates, referring FIG. 1 which attached the drill by 1st embodiment of this invention.
The drill body of the drill according to the first embodiment is formed in a substantially cylindrical shape centering on the axis O with a hard material such as cemented carbide, and the rear end portion thereof is held by the rotating shaft of the machine tool. On the other hand, the tip end portion is the cutting edge portion 10.
[0010]
On the outer periphery of the blade tip portion 10, a pair of chips that twist to the rear side in the drill rotation direction T with a substantially constant twist angle from the portion opened at the tip flank 11 of the blade tip portion 10 toward the rear end side in the axis O direction. The discharge grooves 12, 12 are formed symmetrically with respect to the axis O, and in the intersecting ridge line portion between the wall surfaces 12 A, 12 A facing the front side of the drill rotation direction T and the tip flank 11 in the pair of chip discharge grooves 12, 12, A pair of cutting blades 13 and 13 which form a substantially straight line are formed.
[0011]
The tip flank 11 of the blade tip portion 10 retreats toward the rear end side in the axis O direction from the pair of cutting blades 13 and 13 toward the rear side in the drill rotation direction T, and from the inner peripheral side to the outer peripheral side. Accordingly, it is formed in a substantially conical surface shape so as to recede toward the rear end side in the direction of the axis O, and each of the pair of cutting blades 13 and 13 is given a predetermined clearance angle and tip angle. It has become.
The tip flank 11 is formed with a substantially straight chisel edge 14 passing through the axis O when viewed from the tip side in the direction of the axis O so as to connect the inner peripheral ends of the pair of cutting blades 13, 13. Has been.
[0012]
Further, the outer peripheral surface excluding the pair of chip discharge grooves 12, 12 in the blade edge part 10, that is, the land part 15, as seen in a cross section orthogonal to the axis O, can be understood from FIG. 12, a margin portion 15 </ b> A having a substantially arc shape centering on the axis O, intersecting the outer peripheral side ridge line portion of the inner wall surface 12 </ b> A facing the front side in the drill rotation direction T, and the drill rotation direction T rear side of the margin portion 15 </ b> A And a second picking surface 15B having a substantially arc shape centered on an axis O having an outer diameter that is one step smaller than the arc formed by the margin portion 15A.
The margin portion 15A and the second picking surface 15B, like the chip discharge groove 12, are located on the rear side in the drill rotation direction T from the portion intersecting the tip flank 11 toward the rear end side in the axis O direction. It is formed over substantially the entire length of the cutting edge portion 10 in the direction of the axis O so as to be twisted.
[0013]
Here, when the cutting edge portion 10 is viewed from the front end side in the direction of the axis O, as shown in FIG. 1A, the wall surface 12A facing the front side of the drill rotation direction T in the chip discharge groove 12 and the front end flank 11 The crossed ridgeline part (cutting edge 13) of the cutting edge 13 is substantially linear, whereas the crossed ridgeline part of the wall surface 12B facing the drill rotation direction T rear side in the chip discharge groove 12 and the tip flank 11 is It has a substantially concave curve shape that is recessed toward the front side of the drill rotation direction T.
And, the ridgeline part connecting the intersecting ridgeline part having the substantially straight line shape and the intersecting ridgeline part having the substantially concave curve shape, that is, the intersection of the wall surface 12C constituting the groove bottom in the chip discharge groove 12 and the tip flank 11. The ridge line part is as shown in FIG. 1B, which is an enlarged view of the main part of FIG.
[0014]
That is, in the first embodiment, when the cutting edge portion 10 is viewed from the front end side in the axis O direction, the intersecting ridge line portion between the wall surface 12C constituting the groove bottom of the chip discharge groove 12 and the front end flank 11 is approximately. It is positioned on the intersection point P between the extension line S1 of the cutting edge 13 that forms a straight line and the straight line S2 that passes through the axis O and is orthogonal to the extension line S1.
More specifically, in the intersecting ridge line portion of the wall surface 12C constituting the groove bottom of the chip discharge groove 12 and the tip flank 11, a substantially concave curved portion (the wall surface 12B of the chip discharge groove 12 and the tip flank 11). Near the intersection of a substantially concave curved portion continuing from the intersecting ridge portion and a substantially straight portion (substantially straight portion continuing from the intersecting ridge line portion of the wall surface 12A of the chip discharge groove 12 and the tip flank 11). Is positioned on the intersection point P described above.
[0015]
According to the drill of the first embodiment configured as described above, when the cutting edge portion 10 is viewed from the tip side, the wall surface 12C and the tip flank 11 constituting the groove bottom of the chip discharge groove 12 are formed. Since the intersecting ridge line portion is positioned on the intersection point P, the cutting edge even if it has the same core thickness W as the cutting edge portion 1 of the conventional drill as shown in FIG. It is possible to secure a larger space for the chip discharge groove 12 for discharging chips generated at the chisel edge 14 formed on the tip flank 11 of the portion 10.
[0016]
Therefore, it is possible to improve the discharge of chips generated at the chisel edge 14 even if the tip of the blade tip portion 10 is notched to form a thinning or sub-groove to reduce the rigidity of the blade tip portion 10 carelessly. In connection with this, generation | occurrence | production of chip clogging can be suppressed.
[0017]
Moreover, the drill according to the first embodiment is different from the conventional drill shown in FIG. 4 only in the position of the groove bottom of the chip discharge groove 12, so that the same chip discharge groove as that of the conventional drill is formed. Since an appropriate shape can be obtained by the method, it can be easily manufactured.
In the drill according to the first embodiment, the outer diameter of the cutting edge 13 is set in a range of 0.05 mm to 2.00 mm, and a deep hole that requires step processing at the time of drilling processing. This is particularly effective when processing.
[0018]
Next, although it demonstrates referring FIG. 2 which attached the drill by 2nd embodiment of this invention, the description is abbreviate | omitted using the same code | symbol for the part similar to 1st embodiment mentioned above.
In the second embodiment, the intersecting ridge line portion between the wall surface 12C constituting the groove bottom and the tip flank 11 in the chip discharge groove 12 is shown in FIG. 2 (b) which is an enlarged view of the main part of FIG. 2 (a). It is supposed to be.
[0019]
That is, in the second embodiment, when the cutting edge portion 10 is viewed from the front end side in the axis O direction, the intersecting ridge line portion between the wall surface 12C and the front end flank 11 constituting the bottom of the chip discharge groove 12 is substantially It is positioned closer to the axis O than the intersection P between the extension line S1 of the cutting edge 13 and the straight line S2 perpendicular to the extension line S1 through the axis O.
More specifically, in the intersecting ridge line portion of the wall surface 12C constituting the groove bottom of the chip discharge groove 12 and the tip flank 11, a substantially concave curved portion (the wall surface 12B of the chip discharge groove 12 and the tip flank 11). A substantially concave curved portion continuing from the intersecting ridge line portion is positioned closer to the axis O than the intersection point P, and the substantially concave curved portion and the substantially linear portion (of the chip discharge groove 12). The vicinity of the intersection of the wall surface 12A and the tip flank 11 and the substantially linear portion continuous from the intersecting ridge line portion) is located on the intersection of the inner peripheral end of the cutting edge 13 and the chisel edge 14.
[0020]
Even with the drill according to the second embodiment having such a configuration, it is possible to obtain the same effects as those of the first embodiment described above.
In the second embodiment, when the cutting edge portion 10 is viewed from the front end side in the axis O direction, the intersecting ridge line portion between the wall surface 12C and the front end flank 11 constituting the groove bottom of the chip discharge groove 12 is Even if it is too close to the axis O from the intersection point P, the rigidity of the blade edge portion 10 must be lowered, so the direction in the direction along the straight line S2 between the intersection ridge line portion and the intersection point P described above The distance is in the range of 0.005 mm to 0.01 mm when the drill diameter (outer diameter of the cutting edge 13) is smaller than 0.3 mm, and 0.005 mm to 0.8 mm when the drill diameter is 0.3 mm to 0.8 mm. In the case of a range of 02 mm and a drill diameter exceeding 0.8 mm, it is preferably set appropriately within a range of 0.01 mm to 0.04 mm.
[0021]
Next, a description will be given with reference to FIG. 2 attached with a drill according to the third embodiment of the present invention. The same reference numerals are used for the same parts as those in the first and second embodiments described above, and the description thereof is omitted. Omitted.
The drill according to the third embodiment has substantially the same configuration as that of the second embodiment described above, but the tip flank 11 of the blade edge portion 10 has a plurality of flat surfaces arranged along the circumferential direction. There is a difference in that it has a multi-stage shape composed of flank faces.
[0022]
That is, the tip flank 11 of the blade tip portion 10 includes a first flank 11A, 11A in which a pair of cutting blades 13, 13 are formed on the ridge line portion on the front side of the drill rotation direction T, and the first flank 11A, 11A has a multi-step surface formed by second flank surfaces 11B and 11B continuous to the drill rotation direction T rear side of 11A, and each of the pair of cutting blades 13 and 13 is directed to the drill rotation direction T rear side. Accordingly, a clearance angle that increases in a multistage manner is added.
[0023]
According to the drill of the third embodiment having such a configuration, in addition to being able to obtain the same effect as that of the first embodiment described above, the tip flank 11 is formed in a multi-step surface shape. By doing, the flow of the chip | tip produced | generated in the chisel edge 14 is improved, and the further improvement of chip | tip discharge property can be aimed at.
In addition, since the tip of the blade edge portion 10 is not largely cut out like thinning or sub-grooves, the rigidity of the blade edge portion 10 is not inadvertently lowered.
[0024]
【Example】
Drill according to an example of the present invention (Example 1 shows the drill according to the first embodiment shown in FIG. 1, Example 2 shows the drill according to the second embodiment shown in FIG. 2, Example shows the drill according to the third embodiment shown in FIG. 3) and a conventional drill (the drill shown in FIG. 4 is used as a conventional example), a drilling test for forming a machining hole in a work material by step feed was performed. In this drilling test, a case where 50 holes could be processed with a certain step amount was rated as ◯, and a case where 50 holes could not be processed was rated as x. The results are shown in Table 1.
The drilling conditions are as shown below.
・ Drill diameter (outer diameter of cutting edge 13): 1.0 mm
・ Cutting speed: 80 m / min
-Feed rate: 0.08 mm / rev.
・ Hole depth: 8mm
・ Work material: A7075P
・ Cutting fluid: Emulsion [0025]
[Table 1]

[0026]
As shown in Table 1, in the conventional example, the step amount could be processed only up to 0.5 mm, whereas in Example 1, the step amount was up to 1.0 mm, and in Example 2, the step amount was up to 1.2 mm. Furthermore, in Example 3, it is possible to continue stable drilling without causing chip clogging up to a step amount of 1.5 mm, and Examples 1 to 3 as an example of the present invention are conventional. It turns out that it is far superior to an example.
[0027]
【The invention's effect】
According to the present invention, when the blade edge portion is viewed from the tip side, the intersecting ridge line portion between the wall surface constituting the groove bottom of the chip discharge groove and the tip flank surface is positioned closer to the axis than the intersection point described above. Therefore, while having the same core thickness as the conventional drill, it is possible to increase the space of the chip discharge groove for discharging chips generated at the chisel edge.
Therefore, it is possible to improve the discharge of chips generated at the chisel edge without significantly reducing the rigidity of the blade edge part by forming a thinning or sub-groove by cutting the tip of the blade edge part greatly, The occurrence of chip clogging can be suppressed. Furthermore, although the position of the groove bottom of the chip discharge groove is different from that of the conventional drill, the drill of the present invention can easily obtain an appropriate shape by the same method of forming the chip discharge groove as before. Can be manufactured.
[Brief description of the drawings]
FIG. 1A is a front end view showing a cutting edge portion of a drill according to a first embodiment of the present invention, and FIG. 1B is an enlarged view of a portion X in FIG.
2A is a front end view showing a cutting edge portion of a drill according to a second embodiment of the present invention, and FIG. 2B is an enlarged view of a portion X in FIG.
FIG. 3 is a front end view showing a cutting edge portion of a drill according to a third embodiment of the present invention.
4A is a front end view showing a cutting edge portion of a conventional drill, and FIG. 4B is an enlarged view of a portion X in FIG. 4A.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Cutting edge part 11 Tip flank 12 Chip discharge groove 12A Wall surface 12B which faces the drill rotation direction front side Wall surface 12C which faces the drill rotation direction rear side Wall surface 13 which forms the groove bottom 13 Cutting blade 14 Chisel edge S1 Extension line S2 of cutting blade Straight line P passing through the axis perpendicular to the extension line of the crossing point O Axis line T Drill rotation direction

Claims (2)

A chip discharge groove is formed on the outer periphery of the cutting edge portion, which is the tip side portion of the drill body rotated about the axis, and is open to the tip clearance surface of the cutting edge portion and extends toward the rear end side. A drill in which a cutting edge is formed at a crossing ridge line portion between the wall surface facing the front side of the drill rotation direction and the tip flank,
The outer diameter of the cutting edge is set in a range of 0.05 mm to 2.00 mm,
When looking at the blade edge from the tip side in the axial direction,
The intersection ridge line part of the wall surface constituting the groove bottom of the chip discharge groove and the tip flank is closer to the axis than the intersection of the extension line of the cutting edge and a straight line passing through the axis and perpendicular to the extension line. A drill characterized by being positioned in The drill according to claim 1,
A drill characterized in that the tip flank has a multi-stage shape composed of a plurality of flank surfaces.

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