JPS6042013Y2 - Throw-away drill - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of an indexable drill having a tip having a quadrilateral shape such as a rhombus, a parallelogram, or a square.

Generally, in this type of indexable drill, a pair of square tips having the same shape are removably attached to the tip side of the drill body using a clamp member such as a screw or a piece.

In this case, one of the pair of rectangular tips (the inner tip or the center tip) has two nose portions on the tip side located on opposite sides of the rotation center axis of the drill body, and the other The one (outer periphery side chip) is arranged on the outer periphery side.

In FIG. 1, the inner and outer inserts 1 and 2 are composed of diamond-shaped or parallelogram indexable inserts, and the cutting edge 1a of the inner insert 1 (hereinafter referred to as
The cutting edge ridgeline is also called the cutting edge.

) and the cutting edge ridgeline 2a of the outer peripheral tip 2 are arranged substantially parallel to each other.

However, in this example, the cutting edge line 1a of the inner peripheral chip 1
is used over the entire area from the nose part 3a on the side closer to the rotation center axis XX to the other nose part 3b, so the outer diameter of the cutting edge of the drill or the indexable tip 1
, 2, the balance between the lengths of the cutting edges on the inner and outer circumferential sides cannot be maintained, and as a result, the cutting force is reduced to both cutting edges 1a,
There is an undeniable problem that 2a becomes unstable and it becomes impossible to drill with high accuracy.

Further, in this example, since the chips resulting from cutting are only divided into two in the radial direction, there are many problems in terms of chip disposal.

FIG. 2 shows another example, in which each of the inner and outer inserts 10.20 is constituted by a square indexable insert, and the cutting edge 10a of the inner insert 10 and The cutting edge lines 20a of the outer peripheral tip 20 are arranged to intersect with each other.

Therefore, in this example, the chips caused by cutting are divided into four parts in the radial direction, so that unlike the previous example, the chips can be disposed of better.

However, in this example, the worn cutting edge portion (hatched area in the figure) 21.2 of the outer peripheral tip 20 as shown in FIG.
2 cannot be configured as a new cutting blade because when the cutting blade is replaced as shown in the same figure, the worn part 21 of the cutting blade becomes the cutting blade position to be cut next.

Therefore, depending on the cutting edge arrangement as shown in FIG.
Since the 0a and nose portion cannot be used effectively for cutting, the economic effects of the indexable type cannot be fully obtained.

For reference, the inner peripheral chip 10 is shown in Fig. 4 a and b.
The cutting edge positions of the worn parts 11 and 12 of the cutting edge before and after the cutting blade is replaced are shown, but it is thought that there is no particular problem with the inner tip 10 or the outer tip 20.

This idea was made in consideration of the above points, and the aim is to provide an indexable drill that not only has good chip disposal properties but also fully obtains the economical effects of the indexable type. be.

The indexable drill of this invention can be said to be an improvement of the one shown in Fig. 2, which can divide chips into four parts, and when the cutting edges of the inner and outer chips are exchanged. , in order to allow the cutting edge to be replaced without overlapping the part used as the cutting edge of one tip and the part used as the cutting edge of the other tip, rotation in a plane containing the rotation center axis of the drill body is performed. The feature is that the trajectory is arranged so that it satisfies the following two conditions A and B.

(4) The nose portion of the outer tip near the axis should protrude from the cutting edge line of the inner tip toward the tip of the drill body.

(B) The nose portion of the inner tip that is further away from the axis is projected from the cutting edge line of the outer tip toward the tip of the drill body.

Hereinafter, with reference to the attached drawings (Figures 5 to 10),
The contents of this invention will be clarified through examples of this invention.

5 to 7, a drill body 30 has a mounting portion 31 formed on its rear end side for attachment to the main shaft of a machine, and two tip seats 32 and 33 are formed on its tip side. has been done.

These chip seats 32 and 33 are provided with rhombic or parallelogram-shaped positive indexable chips 100 and 20.
0 is set, and flutes 34 and 35 for discharging chips are provided in the portion continuing from each chip seat 32, 33 in the direction of the mounting portion 31.

The two indexable tips 100, 200 have rounded nose portions 101, 102, 103.1 at each corner thereof.
04; 201, 202, 203, and 204 of the same shape, and a hole 37 for inserting a clamp screw 36 is bored in the center thereof.

Each tip 100, 200 is fixed to the drill body 30 by inserting a clamp screw 36 into the center hole 37 and screwing it into a screw hole 38.39 formed in the tip seat 32.33. Ru.

In this case, these two tips 100 and 200 are arranged in opposite directions with respect to the center of rotation of the drill body 30, with one tip 100 serving as the inner tip and the other tip 200 serving as the outer tip. Each will be configured.

Here, the set position of the inner tip 100 with respect to the drill body 30 is such that the rake face 105 thereof passes through the central axis XX of the drill body 30, and the acute angle nose portion 101 and the obtuse angle nose adjacent thereto A part of the cutting edge ridge line 100a connecting with the obtuse nose portion 102
It is located on the opposite side to the central axis XX, and is positioned further behind the obtuse nose portion 102 in the axial direction.

On the other hand, regarding the set position of the outer tip 200 relative to the drill body 30, it is located on the opposite side of the inner tip 100 with respect to the central axis The obtuse nose portion 202 adjacent to the acute nose portion 201 is positioned at the outermost periphery (that is, the outer diameter of the cutting edge) and is positioned closer to the center than the acute nose portion 201 in the radial direction, and is positioned behind the acute nose portion 201.

Further, the other obtuse nose portion 204 of this outer peripheral tip 200 is positioned closer to the center than the acute angle nose portion 201 in the radial direction, and the other obtuse nose portion 204 in the axial direction is also positioned closer to the center than the acute angle nose portion 201.
It is positioned further back than 1.

FIG. 8 shows the rotation locus of the inner tip 100 and the outer tip 200 in a plane including the central axis XX of the drill body 30.

In this case, the obtuse nose portion 102 of the inner tip 100 intersects the cutting edge 200a of the outer tip 200, and a portion thereof protrudes forward from the cutting edge 200a.

On the other hand, the obtuse nose portion 202 of the outer tip 200 intersects with the cutting edge line 100a of the inner tip 100, and a portion thereof protrudes from the cutting edge line 100a.

In this case, due to cutting edge wear, the cutting edge 100a of the inner tip 100 is similar to the obtuse nose portion 20 of the outer tip 200.
2 point P2 (This point P2 is the starting point of the 1° diagonal.

), and the cutting edge line 2 of the outer tip 200
00a is a point Pi of the obtuse nose portion 102 of the inner tip 100 (this point P is the starting point of the diagonal line 1□).

), it is more preferable if they are located further ahead than

Now, when drilling is performed using a drill with the inner and outer tips 100°200 arranged as above, the cutting area of the inner tip 100 is a part of the cutting edge 100a and the obtuse nose. 102, and the cutting portions of the outer peripheral tip 200 are a part of the obtuse nose part 202, a part of the cutting edge ridge line 200a, and the acute nose part 201.

Therefore, as the ejected chips are divided into four parts in the radial direction, the chip disposal performance is good, and the balance between the cutting forces of each cutting edge on the inner and outer circumferential sides is also maintained. , it is possible to drill holes with high precision.

In addition, even if the cutting edge wears out as drilling progresses, since the inner tip 100 and the outer tip 200 have the same shape, the cutting edge can be replaced in the following manner.
Four cutting edge lines 100a and 2 of each chip 100 and 200
00a and four nose parts 101-104; 201-
204 can be used effectively for cutting, so the economical effects of the throw-away type can be fully demonstrated.

That is, the worn inner tip 100 as shown in FIG. 9a can be replaced as an outer tip as shown in FIG. The outer chip 200 can be replaced as an inner chip as shown in the figure.

Further, as a mode of exchanging cutting blades, the methods shown in FIGS. 3 and 4 can also be adopted.

In addition, in FIG. 9 and FIG. 10, the shaded area indicates the worn part of the cutting edge.

In the above embodiments, a drill with a positive tip 100, 200 in the shape of a rhombus or a square quadrilateral was described, but this invention can also be applied to a drill with a square or rectangular or even negative tip. .

Further, this invention can be applied to a drill having three or more tips, that is, a drill having at least one pair of tips on the inner circumferential side and the outer circumferential side.

Furthermore, this invention proposes a method for supplying cutting oil or air to the cutting part by providing a through hole running in the axial direction in the drill body 30 in order to improve chip evacuation, and a method for forming the flutes 34 and 35 into a spiral shape. It is also effective to use it in combination with methods such as

As mentioned above, in the indexable drill of this invention, chips are discharged in four parts, so chip disposal is good, and the cutting edge and nose can be easily removed when replacing the cutting blade. Since it is used effectively, an excellent advantage can be obtained in that the economic effect of the throw-away type can be fully obtained.

[Brief explanation of drawings]

Figures 1 and 2 are diagrams of the large bottom shape and the cutting edge arrangement of the indexable tip drilled by a conventional indexable drill, respectively, and Figure 3 is a diagram showing the cutting blade exchange in the drill of Figure 2. 4 is a diagram similar to FIG. 3, a is a diagram showing the worn part of the cutting edge of the inner insert, b is a diagram showing the state where the cutting blade has been replaced,
Fig. 5 is an overall view showing an embodiment of the indexable drill of this invention, Fig. 6 is a left side view thereof, Fig. 7 is a partially enlarged view of Fig. 5, Figure 8 is a diagram showing the hole bottom shape and the cutting edge arrangement of the indexable tip drilled by the indexable drill of this invention, and Figures 9 and 10 are diagrams showing the cutting blade exchange in the drill of this invention. Figure 9a is a diagram showing the wear part of the cutting edge of the inner insert.
The same figure shows a state in which the cutting edge has been replaced from the inner tip to the outer tip, and Fig. 10a is a diagram showing the worn part of the cutting edge of the outer tip.
This is a state diagram of the same figure, but with the cutting edge changed from the outer tip to the inner tip. 30...Drill body, 100...Inner circumference side tip, 200...Outer circumference side tip, 101~
104°201~204...Nose part, 100
a, 200a... Cutting edge ridgeline.

Claims (2)

[Scope of utility model registration request] (1) An indexable drill in which at least one pair of rectangular tips of the same shape is removably attached to the tip side of the drill body by a clamp member, and the pair of tips have two nose portions on the tip side. The inner tip is composed of an inner tip disposed on opposite sides of the rotation center axis of the drill body and an outer tip disposed on the outer circumference side of the inner tip. and the outer peripheral side insert are mutually interchangeable cutting edges, and when exchanging cutting edges, the part used as the cutting edge of one insert and the part used as the cutting edge of the other insert do not overlap each other, and the cutting edge is An indexable drill, characterized in that the drill body is arranged so that its rotation locus in a plane including the rotation center axis satisfies the following two conditions A and B so that the drill body can be replaced. ■ The nose portion of the outer tip near the axis should protrude from the cutting edge line of the inner tip toward the tip of the drill body. (B) The nose portion of the inner tip that is further away from the axis is projected from the cutting edge line of the outer tip toward the tip of the drill body. (2) The indexable drill according to claim 1, wherein the square tip has a rhombus shape.