JP2562258Y2 - Milling tool - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a milling tool, and more particularly, to preventing a throw-away insert mounted on a tool body from loosening or chipping and improving a chip discharging ability. Related to milling tools.

[0002]

2. Description of the Related Art When rolling an outer peripheral portion, a hole portion, a groove portion, or the like of a workpiece, an end mill which is a rolling tool having a plurality of throw-away tips mounted on an end surface and an outer peripheral portion of a tool body is used. .

FIG. 5 is a side view of an end mill 2 of this type.
FIG. 6 shows a rolling state by the end mill 2. The end mill 2 has a cylindrical main body 4 that rotates around an axis.
And a plurality of chip discharge grooves 6 formed by cutting out the outer periphery 4 a of the main body 4, and a cutting blade portion 8 provided between adjacent chip discharge grooves 6. A throw-away tip 12 is detachably attached to an edge of the cutting blade 8 on the chip discharge groove 6 side by a clamp screw or the like (not shown).

[0004]

Generally, in the end mill 2 of this type, the protrusion amount A of the throw-away tip 12 from the outer periphery 4a of the main body 4 is set to about 1 mm to 2 mm. When the feed amount B of the work W is set to be large, the gap defined between the outer periphery 4a of the main body 4 and the work W is narrowed, and when vibration or chatter occurs in the main body 4, The inconvenience that the workpiece 4a interferes with the workpiece 4a has become apparent. Further, since the smooth discharge of the chips is hindered by the narrowing of the gap, there is a problem that the chips are caught and the throw-away tip 12 is damaged.

On the other hand, when the protrusion amount A of the throw-away tip 12 is set to be large in order to solve the above-mentioned inconvenience, the holding force of the throw-away tip 12 decreases in accordance with the increase in the protrusion amount A. Therefore, for example, it is conceivable to increase the size of the throw-away tip 12 to increase the area of the locking surface 10a of the throw-away tip mounting portion 10. However, as the area of the locking surface 10a increases, Inconvenience that rigidity of itself is reduced occurs.

Accordingly, a technical idea relating to a "rolling tool" made to overcome the above-mentioned inconvenience is disclosed in Japanese Utility Model Publication No. 2-3376. FIG. 7 shows a front view of the milling tool 20. The milling tool 20 is moved from the base end 22a to the front end 22a.
b, and a stepped or tapered main body portion 22 gradually reduced in diameter toward the center of the main body 22 and a chip discharge groove 2 of a cutting blade portion 24 of the main body portion 22.
And a throw-away tip 28 attached to the edge on the sixth side. With such a structure, it is possible to avoid interference with the workpiece and to improve the chip discharging performance.

However, in the milling tool 20, the main body portion 22 has a shape gradually reduced in diameter from the base end portion 22a toward the front end portion 22b. Reduced tip 2
2b, the throw-away tip mounting portion 30
The area of the locking surface 30a at the time is reduced. As a result, the throw-away tip mounting portion 30 cannot sufficiently counteract the shearing stress and bending moment generated in the throw-away tip 28 due to the addition of cutting resistance, and chipping (breakage) occurs in the throw-away tip 28. And the inconvenience of loosening is pointed out.

Therefore, the present invention can improve the rigidity and durability of the tool by improving the chip discharging ability and preventing the occurrence of chipping (looseness) and loosening of the indexable insert due to cutting resistance. The purpose is to provide a simple milling tool.

[0009]

To SUMMARY OF THE INVENTION To achieve the above object, the present invention is, on the outer peripheral portion of the rotatable tool body and the rotation axis of the axis, multiple throw-away along the axial direction In a milling tool having a chip mounted thereon, an outer peripheral portion of the tool main body has one of adjacent ones along a circumferential direction.
An outer peripheral surface is formed between the chip discharge groove and the other chip discharge groove.
The outer peripheral surface gradually increases in radial distance from the rotation axis toward the rear in the rotation direction of the throw-away tip.
It is formed in a circular arc shape which follows reduction, the beginning of the arc-shaped outer peripheral surface of the
The end is a swage attached to a part close to one chip discharge groove.
Continuing with the lower chip, the end of the outer peripheral surface is the other
Characterized by being formed so as to be continuous with the chip discharge groove .

[0010]

In the cutting tool according to the present invention, the outer peripheral portion of the cutting edge portion of the tool body is rotated from the vicinity of the rake face toward the rear in the rotational direction.
The distance from the axis of the rotation center to the axis is gradually reduced. Therefore, at the time of cutting, a sufficient gap for discharging chips can be formed between the work and the outer peripheral portion, and the cutting resistance can be sufficiently counteracted.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a preferred embodiment of a rolling tool according to the present invention.

FIG. 1 is a side view of an end mill according to the present embodiment, and FIG. 2 is an explanatory sectional view of the end mill. In FIG. 1 and FIG. 2, reference numeral 40 indicates an indexable tip-mounted end mill. The indexable tip-mounted end mill 40 is
Basically, a cylindrical tool main body 42 held rotatably about the rotation axis O _1, and spiral cutting blades 44 a to 44 d provided on the outer periphery of the tool main body 42,
Spiral chip discharge grooves 52a to 52d provided between adjacent cutting blades 44a to 44d, and the respective cutting blades 44a
To 44d, and a plurality of indexable inserts 60a to 60d removably attached to the inserts.

The cutting blades 44a to 44d are provided with a rake face 45.
a to 45d, outer peripheral surfaces 47a to 47d, and back surface 49
a to 49d, and a throw-away tip mounting portion 62 provided at the edge of the rake faces 45a to 45d and the outer peripheral faces 47a to 47d.

In the present embodiment, the cutting blades 44a to 44d and the chip discharging grooves 52a to 52d have the same shape, respectively, so that the following description will be made using the cutting blade 44a and the chip discharging groove 52a. However, description of other parts having the same shape will be omitted.

The outer peripheral surface 47a includes a virtual circle L ₁ of radius R ₁ centered on the rotation axis O ₁ of the tool body 42, the intersection point P ₁ between the extension line of the rake face 45a of the cutting edge 44a as, times displaced by a predetermined amount Q ₂ to the rake face 45a side
Is formed in an arcuate shape as part of a virtual circle L ₂ of radius R ₂ centered on the rotation axis O ₂ (see FIG. 3). The arc-shaped
The starting end 46 of the outer peripheral surface 47a is adjacent to each other along the circumferential direction.
Is attached to a portion close to one of the chip discharge grooves 52a.
The outer peripheral surface 4 continues to the throw-away tip 60a
The end 48 of 7a is continuous with the other chip discharge groove 52b.
(See FIGS. 2 to 4). Paraphrase
If, outline of the outer peripheral surface 47a is directed to the back 49a of the rake face 45a side, i.e., the distance from the rotation axis O ₁ toward the direction of rotation behind the cutting insert mounted end mill 40 is gradually reduced It is formed as follows.

The outer peripheral surface 47a and the rake face 4
At the edge where the wall surface intersects with the wall 5a, a throw-away tip attaching portion 62 for attaching the throw-away tip 60a is provided.
Are formed. The indexable tip mounting portion 62
Consists of a mounting seat 62a extending substantially in the circumferential direction and a locking surface 62b extending substantially in the radial direction.

The throw-away tip 60a attached to the throw-away tip mounting portion 62 has a substantially triangular shape, and each side face is provided with a mounting seat 62a and its locking surface 6a.
2b, and is attached by a tightening screw 66.

The indexable tip-mounted end mill 40 of the present embodiment is basically constructed as described above, and its operation and effects will be described below.

In order to cut the workpiece W using the indexable tip-mounted end mill 40, first, the base end of the tool main body 42 is rotated by a means such as a chuck with respect to a rotation drive source (not shown). Fix it. Then, the start of the rotation driving source, the throw-away tip mounting end mill 40 starts rotating in the rotation direction indicated by arrow T _1. Then, the workpiece W is cut at a predetermined feed amount by the throw-away tips 60a to 60d protruding from the outer periphery of the tool body 42 of the throw-away tip mounting end mill 40.

At this time, the gap 64 between the outer peripheral surfaces 47a to 47d of the respective cutting blades 44a to 44d and the work W is gradually enlarged toward the rear in the rotation direction of the end mill 40 on which the indexable insert is mounted. For example, a chip discharge groove 5
The chips generated on the rake face 45b on the 2b side do not bite into the gap 64 on the side of the cutting blade portion 44a, thereby preventing biting of the chips and lowering of the chip discharging ability due to an increase in cutting resistance, and thus cutting. The ability itself can be improved.

Further, the locking surface 62b of the throw-away tip mounting portion 62 has a sufficient area, so that the throw-away tips 60a to 60d can be reliably held. Thereby, the occurrence of chipping or loosening is suitably avoided. Further, the tool body 42 does not need to have its tip portion reduced in diameter, so that the rigidity of the tool body 42 is sufficiently ensured. Therefore, even when the feed amount is set to be large, the tool body 42 itself does not need to be reduced. Vibration and chatter are avoided.

Next, another embodiment of the milling tool according to the present invention will be described. Throw-away tip mounting end mill 70 shown in FIG. 4, the cutting edge 71a, 71b, the outer peripheral surface 73a that constitutes the ..., 73b, ..., and a virtual circle L ₁ around the rotation axis O ₁ of the tool body 74 , The cutting blade 71
a, as 71b, ... an intersection P ₂ of the locking surface 76a of the throw-away tip mounting portion 76 of the rake face 72a, 72
b, ... it is formed as part of a virtual circle L ₃ of the radius R ₃ centered at O ₃ was displaced by a predetermined amount Q ₃ on the side. Therefore,
The outer lines of the outer peripheral surfaces 73a, 73b,.
a, 72b, ... back from the side 75a, 75b, ... the distance between the rotation axis O ₁ directed to be formed so as to reduce lozenge. As a result, the same operation and effect as in the case of the above-described indexable tip-mounted end mill 40 can be obtained.

[0023]

According to the present invention, the outer peripheral portion of the cutting portion of the tool body is formed by gradually decreasing the distance from the axis of the rotation center from the vicinity of the rake face to the rear in the rotational direction. I have. Therefore, at the time of cutting, a sufficient gap for discharging chips can be defined between the work and the outer peripheral portion without reducing the area of the locking surface of the work mounting portion. As a result, it is possible to improve the chip discharging capability, sufficiently counteract the cutting resistance, prevent chipping and loosening of the throw-away insert, and improve the rigidity and durability of the tool.

[Brief description of the drawings]

FIG. 1 is a side view of a milling tool according to the present invention.

FIG. 2 is an explanatory sectional view of the milling tool shown in FIG. 1;

FIG. 3 is an enlarged explanatory view of a main part of the milling tool shown in FIG. 2;

FIG. 4 is an enlarged explanatory view of a main part of another embodiment of the milling tool according to the present invention.

FIG. 5 is a side view of a conventional milling tool.

FIG. 6 is an explanatory view of a state in which the turning tool shown in FIG. 5 is turning;

FIG. 7 is a front view of a milling tool according to another related art.

[Explanation of symbols]

 40, 70: End mill with a throw-away tip 42: Tool body 44a to 44d: Cutting edge 45a to 45d: Rake surface 47a to 47d: Outer surface 49a to 49d: Back surface 52a to 52d: Chip discharge groove 60a to 60d: Throw Away tip 62: throw-away tip mounting portion 62a: mounting seat 62b: locking surface 64: gap 66: tightening screw

Claims (1)

(57) [Scope of request for utility model registration] The outer peripheral portion of claim 1] axis of the rotary shaft and to rotate freely tool body, the milling tool cutting insert is mounted in multiple along the axial direction, the outer periphery of the tool body Are adjacent to each other along the circumferential direction
Between the one chip discharge groove and the other chip discharge groove
A surface is formed, and the outer peripheral surface is
Radial direction from the rotation axis toward the rear
Is formed in an arc shape in which the distance gradually decreases, and the starting end of the arc-shaped outer peripheral surface is close to one of the chip discharge grooves.
To the throw-away tip attached to the part
So that the end of the outer peripheral surface is continuous with the other chip discharge groove
A milling tool characterized by being formed .