JP2010234461A - Insert-type drill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insert-type drill capable of meeting both demands of high rigidity and high swarf dischargeability by strictly defining an angle of torsion of a flute based on a specific setting formula. <P>SOLUTION: An arbitrary plane vertical to an axis line O of a holder 1 is defined as a standard plane P0 and n planes parallel to the standard plane P0 and arranged at equal intervals are defined as reference planes P1-Pn. Further, angles of torsion at intersections (C1-Cn) of an opening 5A of the flute 5 with the reference planes P1-Pn are defined as &theta;1, &theta;2, ..., &theta;n from the tip of the holder 1. Then, a setting formula is specifies as "&theta;n=&theta;1+(n-1)d" (d refers to a coefficient). <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an insert type drill having high rigidity and excellent chip discharge performance.

Conventionally, the technique shown by patent document 1 and 2 is shown as this kind of drill.
In the technique described in Patent Document 1, a chip discharge groove extending from the distal end toward the proximal end is formed on the outer periphery of a drill portion (cutting edge portion) located at the distal end portion of the substantially cylindrical tool body, A throw-away type drilling tool in which a throw-away tip having a cutting edge is mounted at the tip of these chip discharge grooves, the tool as the chip discharge groove moves from the tip side toward the base side The flute is directed toward the rear side in the rotational direction, and the twist angle is formed so as to become smaller toward the base end side.
The technique described in Patent Document 2 has a drill structure in which a cutting edge portion made of cemented carbide is provided at the tip portion and a spiral chip discharging groove is formed on the spiral side portion on the shank side portion. The twist angle of the groove with respect to the axis is formed at an angle gradually decreasing from the drill tip to the groove end portion of 0 °. Specifically, the twist angle with respect to the axis of the chip discharging groove is The angle gradually decreasing from the drill tip to 0 ° at the groove end is from 20 ° to 30 ° to 0 °.

JP-A-10-244411 Japanese Utility Model Publication No. 62-188313

By the way, in the drill as described above, the chips are sent out along the flute torsion, which is a chip discharge groove, so that the twist angle of the chip discharge groove is increased in order to send out the chips smoothly. That's fine. However, if the helix angle is increased, the entire length of the chip discharge groove becomes longer, so the generated chips generated at the tip stay in the groove while being sent out to the base end side, and instead the chip is discharged. There is a risk that the property may be impaired.
On the other hand, if the twist angle of the flute described above is reduced in order to avoid such problems, the length of the chip discharge groove is shortened and the rigidity of the drill is increased, but the action of pushing the chips to the proximal end side is reduced. . As a result, it is not possible to obtain a sufficient driving force for discharging the chips out of the hole during cutting, and especially during deep hole processing, the cutting resistance due to chip clogging increases, and the insert may be damaged depending on the situation. As a result, the drilling is interrupted.

In consideration of such problems, the flute twist angle as shown in Patent Documents 1 and 2 is set to gradually decrease toward the base end side. It was not clear whether the best cutting could be done by setting the twist angle, and in this respect, the provision of new technology was expected.
The present invention has been made in view of the above-described circumstances, and by strictly determining the twist angle of the flute based on a specific setting formula, both high rigidity and high chip dischargeability can be satisfied. The purpose is to provide an insert type drill.

  In order to solve the above problems, the present invention proposes the following means. That is, in the present invention, a flute is formed on the outer periphery of the holder so as to extend from the distal end side toward the proximal end side and the torsion angle continuously changes, and the insert having an insert including a cutting blade at the distal end of the flute In the case of a drill, wherein one plane perpendicular to the axis of the holder is a reference plane, and n planes parallel to the reference plane and arranged at equal intervals are used as reference planes, the reference plane and the The torsion angles at the intersections with the flute openings are θ1, θ2,... Θn from the holder tip side, and the setting equation at this time is “θn = θ1 + (n−1) d (d: coefficient ) ”.

  Further, in the present invention, the holder has a cutting blade portion on which the flute is formed and a substantially cylindrical shank portion, and a middle portion thereof includes a connection portion between the cutting blade portion and the shank portion. A tapered flange is provided, and the opening of the flute on the tip end side of the tapered flange of the holder is formed in parallel with the holder axis.

  The present invention is characterized in that the twist angle decreases as the flute moves from the distal end side toward the proximal end side.

  According to the present invention, when one plane perpendicular to the axis of the holder is a reference plane, and n planes parallel to the reference plane and arranged at equal intervals are used as reference planes, The twist angle at the intersection with the reference plane is θ1, θ2,... Θn from the tip of the holder, and the setting equation at this time is “θn = θ1 + (n−1) d (d: coefficient) Therefore, high rigidity and chip discharge performance can be achieved at the same time.

That is, for example, in a drill having a flute that becomes a cycloid curve when deployed, it has a high chip discharge property, but the torsional shape of the tip is large and the length of the flute is also long, The holder rigidity is lowered. However, in the drill of the present invention, since the torsional angle of the portion having a torsional shape at the tip is small, the rigidity of the holder is prevented from lowering compared to a drill having a flute that becomes a cycloid curve when deployed. be able to. Moreover, although the drill of this invention is inferior to the drill which has a flute used as a cycloid curve about the chip | tip discharge | emission property, compared with the drill which has a fixed helix angle, it has shown the outstanding performance.
As a result, in the insert type drill of the present invention, by determining the torsion angle of the flute based on a specific setting formula, a drill having a flute having a constant torsion angle and a drill having a flute groove to be a cycloid are not played simultaneously. It is possible to satisfy both high rigidity and high chip dischargeability.

It is a figure which shows the insert type drill concerning one Embodiment of this invention, Comprising: (A) is a perspective view, (B) is a front view, (C) is a side view. It is a figure which shows the twist angle in each reference plane of the insert type drill concerning this embodiment, Comprising: (A) is the twist angle (theta) 1 in the reference plane P1, (B) The twist angle (theta) 2 in the reference plane P2, (C ) Shows the twist angle θ3 on the reference plane P3, and (D) shows the twist angle θn on the reference plane Pn. It is a graph which shows the relationship between a plane number (= n) and a torsion angle, (A) is a drill which becomes an equidistant sequence torsion angle concerning this embodiment, (B) is an equal torsion angle used as a comparative example, and Shows the drill. It is a graph which shows the position (horizontal axis) of the intersection part along the length direction of the holder 1, and the twist angle (vertical axis) in this intersection part. It is the graph showing the difference in the discharge time of the chip which arises at the time of a hole processing by the difference in the twist angle of a flute.

An insert type drill according to an embodiment of the present invention will be described with reference to FIGS.
As shown in FIGS. 1 (A) to 1 (C), a holder 1 serving as a drill body is integrally formed in a substantially cylindrical shape centering on an axis O with a steel material or the like, and its base end side (arrow a in FIG. 1). 2 is a shank portion 2, and a cutting edge portion 3 is formed through a taper flange portion 4 on the distal end side (left side indicated by an arrow b in FIG. 1).
The tapered flange portion 4 is a connecting portion between the cutting edge portion 3 and the shank portion 2, and is located in the intermediate portion 1 </ b> A of the holder 1.

  A pair of flutes 5 serving as chip discharge grooves are formed on the outer periphery of the cutting edge portion 3. The taper flange is formed so that the flute 5 and the axis O are opposed to each other, and the tip flange flank 6 is opened toward the proximal end side and twisted toward the rear side in the drill rotation direction T toward the proximal end side. It is formed so as to reach part 4. Further, the opening 5A of these flutes 5 has a twist angle determined based on a predetermined setting formula, which will be described later.

In the present embodiment, insert mounting seats 7 are formed at the front ends of the wall surfaces of the flutes 5 facing the drill rotation direction T so as to open to the front end flank 6. A cutting insert 8 made of a hard material such as a hard alloy is detachably attached with its cutting edge 9 protruding from the tip flank 6.
The insert mounting seat 7 and the cutting insert 8 are arranged so as to be shifted on the inner peripheral side and the outer peripheral side of the holder 1, and the rotation trajectories around the axis O of the cutting edges 9 overlap each other to cut the workpiece. Form holes in the material.

Next, with reference to FIGS. 2A to 2D and FIGS. 3A and 3B, the installation position of the opening 5A of the flute 5 arranged to be twisted to the cutting edge 3 of the holder 1 will be described. I will explain.
First, as shown in FIGS. 2A to 2D, an arbitrary plane perpendicular to the axis O of the holder 1 and in the vicinity of the insert mounting seat 7 is defined as a reference plane P0 and is parallel to the reference plane P0. N planes are formed so as to have a predetermined mutual interval (indicated by the symbol L).
These n planes are referred to as “reference planes P1 to Pn”, and the twist angles at the intersections (indicated by reference numerals C1 to Cn) between the reference planes P1 to Pn and the opening 5A of the flute 5 are as follows. When θ1, θ2,... Θn from the front end side of the holder 1, the setting formula for the twist angles θ1 to θn is defined as “θn = θ1 + (n−1) d (d: coefficient)”. .

Here, the twist angles θ1 to θn indicate angles formed between the axis O of the holder 1 and the flute 5 (the central axis thereof) at each of the intersections C1 to Cn, and the specific value is the length of the holder 1 It is obtained from the number of reference planes (= n) divided in the direction at a constant interval L and a predetermined value (d) determined based on this.
Further, the intersection Cn between the nth reference plane Pn and the opening 5A of the flute 5 is located in the intermediate portion 1A along the length direction of the holder 1 as shown in FIG. .

The torsion angles θ1 to θn determined by such setting equations are shown in FIGS. 2 (A) to 2 (D), respectively.
As shown in these drawings, the twist angle θ1 indicates an angle formed by the axis O of the holder 1 at the intersection C1 and the flute 5 (shown in FIG. 2A), and the twist angle θ2 indicates the intersection portion. The angle between the axis O of the holder 1 at C2 and the axis of the flute 5 is shown (shown in FIG. 2B), and the twist angle θ3 is the difference between the axis O of the holder 1 at the intersection C3 and the flute 5 The angle formed is shown (shown in FIG. 2C). In addition, the last twist angle θn indicates an angle formed by the flute 5 and the axis O of the holder 1 at the intersection Cn (shown in FIG. 2D).
In this example, based on the above setting formula, the twist angle θ1 of the first reference plane P1 is 18.2 °, the twist angle θ2 of the second reference plane P2 is 14.3 °, and the third In this example, the torsion angle θ3 of the reference plane P3 is set to 10.4 ° (here, the coefficient d in the setting equation is −3.9 °). In addition, the nth twist angle θn located at the intermediate portion 1A along the length direction of the holder 1 is set to 0 °.

The relationship between the numbers of the reference plane P0 and the reference planes P1 to Pn according to this embodiment and the twist angles θ0 to θn of the flutes 5 in these planes P0 to Pn is shown in FIGS. It is.
In FIG. 3A, since the plane number increases, the torsion angles θ0 to θn gradually decrease, and the nth torsion angle θn located in the intermediate portion 1A of the holder 1 (FIG. 3A). Here, n = 10) indicates the torsion angle of the arithmetic progression according to the present embodiment, which is 0 °. On the other hand, FIG. 3B shows a comparative example with the insert type drill of the present embodiment, and the flute twist angles θ0 to θn are constant regardless of the planes P0 to Pn. The twist angle is shown. FIG. 3 shows a graph including the twist angle θ0 of the reference plane P0. However, the twist angle θ0 may deviate from the relationship between the torsion angle twist angle and the constant twist angle.

FIG. 4 is a graph showing the positions (horizontal axis) of the intersection points C1 to Cn along the length direction of the holder 1 and the twist angles (vertical axis) at the intersection points C1 to Cn. In this graph, when the length of the tip and the base of the flute 5 is 80 mm and the angle is twisted by 50 degrees, along the length direction of the holder 1, the arithmetic sequence according to the present embodiment Various forms of flute, such as lead (denoted by symbol (A)), constant lead as a comparative example (denoted by symbol (B)), and cycloid curve (denoted by symbol (C)) when expanded It shows changes in the twist angles θ1 to θn at the time.
And it can be said that the twist angle (vertical axis) shown here means a change in the twist angles θ0 to θn of the flute 5 that becomes a chip discharge groove when the drill 1 is developed in a planar shape.

  Moreover, FIG. 5 shows the difference in the discharge time of the chip | tip which arises at the time of a hole drill about the equidistant sequence lead concerning this embodiment, the fixed lead used as a comparative example, and a cycloid curve when it develops. Actually, a slope corresponding to a flute that is an arithmetic sequence lead, a constant lead, and a cycloid curve is provided, and the time it takes to reach the bottom from the top when rolling the ball along this slope is expressed as a percentage The discharge time rate of the equidistant sequence read and the cycloid curve when the discharge time of a constant lead is 100% is shown.

Then, as can be seen with reference to the graph of FIG. 4, in a drill having a flute that becomes a cycloid curve when expanded (indicated by symbol (c)), the arithmetic sequence lead (symbol (a)) according to the present embodiment is used. ) And a constant lead (indicated by symbol (B)) as a comparative example, the torsional angle (twisting angle on the vertical axis) of the tip becomes larger, and the length of the flute In addition, since the length becomes longer, there is a problem that the rigidity is lowered.
In addition, as shown by the symbol (b) in FIG. 4, a drill having a flute with a constant lead is advantageous in terms of rigidity because the flute is relatively less twisted, but as shown in FIG. There exists a problem that the time rate of waste discharge is high and chip discharge property is inferior.
Further, as shown in FIG. 5, it is confirmed that the best chip discharging property is a drill having a flute that becomes a cycloid curve when deployed. There is a problem that the rigidity is low.
Then, to summarize such points, the drill having the flute 5 serving as the arithmetic sequence lead according to the present embodiment has higher rigidity than the drill having the flute serving as the cycloid curve, and has a constant lead flute. Therefore, it is possible to achieve a high effect in both rigidity and chip discharging performance.

As described above in detail, in the machining insert type drill according to this embodiment, an arbitrary plane perpendicular to the axis O of the holder 1 is defined as a reference plane P0, and n parallel to the reference plane P0 and arranged at equal intervals. When the planes are the reference planes P1 to Pn, the twist angle at the intersection (C1 to Cn) between the opening 5A of the flute 5 and the reference planes P1 to Pn is defined as θ1 , Θ2,..., Θn, and the setting equation at this time is set to “θn = θ1 + (n−1) d (d: coefficient)”, so that high rigidity and chip discharge performance can be achieved simultaneously. Can do.
In other words, a drill having a flute that becomes a cycloid curve when deployed exhibits high chip evacuation properties, but the torsional shape of the tip is large and the flute length is long, so that the rigidity is high Low. However, in the drill according to the present embodiment, the torsional angle of the portion having a torsional shape at the tip is small, so that the rigidity of the tip is higher than that of a drill having a flute that becomes a cycloid curve when deployed. A decrease can be prevented. Moreover, although the drill of this embodiment is inferior to the drill which has a flute which becomes a cycloid curve (refer FIG. 4), compared with the drill which has a fixed helix angle, the drill of this embodiment has shown excellent performance. (See FIG. 5).
As a result, in the insert type drill according to the present embodiment, by determining the flute torsion angle based on a specific setting formula, high rigidity that is not simultaneously achieved by a drill having a constant torsion angle and a drill having a flute that is a cycloid. And it becomes possible to satisfy | fill both high chip discharge | emission characteristics.

  In addition, how many "n" of the reference planes P1 to Pn are determined is appropriately determined based on the length of the cutting edge portion 3 of the holder 1 and the interval L between the plurality of reference planes P1 to Pn provided. Moreover, you may provide the table which defined the relationship between the length of the cutting blade part 3 of these holders 1, and the space | interval L of the reference planes P1-Pn previously.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.

DESCRIPTION OF SYMBOLS 1 Holder 1A Middle part 2 of a holder 2 Shank part 3 Cutting edge part 4 Tapered flange part 5 Flute 5A Opening part 8 Cutting insert O Holder axial line P0 Reference plane P1-Pn Reference plane C1-Cn Intersection part θ1-θn Twist angle

Claims (3)

A flute is formed on the outer periphery of the holder so as to extend from the distal end side toward the proximal end side and the twist angle continuously changes, and an insert type drill having an insert including a cutting edge at the distal end of the flute,
When one plane perpendicular to the axis of the holder is a reference plane, and n planes parallel to the reference plane and arranged at equal intervals are used as reference planes, the reference plane and the opening of the flute The twist angle at the intersection is θ1, θ2,... Θn from the tip of the holder, and the setting equation at this time is defined as “θn = θ1 + (n−1) d (d: coefficient)”. Features an insert type drill. The holder has a cutting edge portion on which the flute is formed and a substantially cylindrical shank portion, and a taper flange serving as a connection portion between the cutting blade portion and the shank portion is provided at an intermediate portion thereof. And
The insert-type drill according to claim 1, wherein an opening of the flute on a tip end side of the tapered flange of the holder is formed in parallel with a holder axis.   The insert type drill according to claim 1 or 2, wherein the twist angle decreases as the flute moves from the distal end side toward the proximal end side.

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