JPH0760512A - Throwaway tip - Google Patents

Abstract

PURPOSE:To set an axial direction rake angle and a diametric direction rake angle as large as possible on the positive angle side while securing a thickness H at a forward end part of a tool main body holding a tip main body. CONSTITUTION:One end surface 33 as a rake face of a tip main body 32 is formed as an inclined surface to be directed toward the other end surface 35 as it gets apart from a nose part 34. A ridge line formed by one end surface 33 and a side surface 37 thus becomes a cutting blade 38, and these cutting blades 38 are also inclined toward the other end surface 35 respectively. A breaker 39 is formed along the cutting blade 37. An axial direction rake angle and a diametric direction rake angle are thus set on the positive angle side. Cutting performance can thus be improved while maintaining rigidity of a forward end part of a tool main body 1 for holding a tip 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throw-away tip mounted on various kinds of throw-away tools.

[0002]

2. Description of the Related Art As a throw-away tool equipped with such a throw-away tip (hereinafter, simply referred to as a tip), for example, a throw-away type end mill whose tip portion is shown in FIGS. Are known.

In this end mill, the wall thickness of the tip portion 2 is gradually increased from the tip end 2 of the tool body 1 having a multi-columnar shape whose diameter decreases toward the tip toward the base end side in the tool axis C direction. The chip pocket 3 is formed so as to be large. The tip mounting seat 5 is formed on the bottom surface 4 of the tip pocket 3 in the direction of the tool axis C and facing the corner on the side facing the tool rotation direction. The chip 7 is thus fixed.

The chip 7 is a positive chip of a flat plate shape in which one end surface 9 of the chip body 8 serving as the rake face forms a substantially parallelogram in plan view. The one end surface 9 and the chip mounting seat 5 are provided. The other end surface 10 of the chip body 8 which is a seating surface in contact with is molded in parallel with each other. The nose portions 11, 11 of the tip 7 are formed at a pair of acute-angled portions located on one diagonal of the parallelogram forming the one end surface 9. Then, the side surfaces 12 adjacent to each other with the nose portion 11 of the chip body 8 interposed therebetween,
Intersecting ridgeline 1 formed by each of 13 and the one end surface 9
Cutting edges 16 and 17 are formed so as to be continuous with the nose portion 11 on both sides of the parallelogram-shaped nose portion 11 forming the one end surface 9, respectively. It is a side cutting edge and a bottom cutting edge. Further, a mounting hole 18 is formed in the central portion of the chip body 8 so as to penetrate in the thickness direction of the chip body 8.

On the other hand, in the tip mounting seat 5 on which the tip 7 is mounted, the above-mentioned cutting edges 16 and 17 project from the outer peripheral surface and the tip surface of the tip portion 2 of the tool body 1 when the tip 7 is mounted. It is formed in a shape that engages with the outer shape of the chip body 8. In addition, the other end surface 10 of the chip body 8
Similarly to the bottom surface 4 of the chip pocket 3, the bottom surface 19 of the tip mounting seat 5 on which the tool seat 1 is seated is such that the wall thickness H of the tip portion 2 of the tool body 1 gradually increases from the tip of the tool body 1 toward the base end side. In addition, the flat surface is formed by inclining in a direction oblique to the tool axis C.

Further, a screw hole (not shown) is provided at the center of the bottom surface 19 of the chip mounting seat 5, and the axis of the screw hole is the chip body 8 when the chip 7 is mounted on the chip mounting seat 5. Is slightly eccentric toward the corner of the tip mounting seat 5 on the base end side in the tool axial direction with respect to the axis of the mounting hole 18 formed in the central portion of the. An oval recess 20 is formed in a plan view at a corner of the tip mounting seat 5 on the base end side in the tool axis direction.

In the throw-away type end mill having such a structure, the tip 7 is mounted on the tip mounting seat 5 of the tool body 1 and the clamp screw 6 is tightened so that the other end surface 10 of the tip body 8 is mounted on the tip mounting seat 5. The chip 7 is seated and fixed by being pressed by the bottom surface 19 of the. Along with this, the chip body 8 is pressed against the corner side of the chip mounting seat 5 due to the eccentricity between the axis of the screw hole of the chip mounting seat 5 and the axis of the mounting hole 18 of the chip body 8, whereby the chip body 8 is pressed. Tool body 1 side surface 1 located on the base end side
2 and the side surface 1 adjacent to the side surface 12 with the nose portion 11 interposed therebetween.
3 and the wall portions 21 and 22 of the tip mounting seat 5 are brought into contact with each other, thereby projecting from the outer peripheral surface of the tip end portion 2 of the tool body 1 and the outer peripheral side cutting edge of the end mill and the bottom cutting edge. The positions of the cutting blades 16 and 17 are accurately positioned. Further, in the end mill of this example, the recesses 20 formed at the corners of the tip mounting seat 5 prevent contact of the vicinity of the nose portion 11 of the tip 7 with the tip mounting seat 5, so that the cutting edges 16 and 17 are provided. There is an advantage that the positioning accuracy of the chip mounting seat 5 can be maintained and the chip mounting seat 5 itself can be easily molded.

[0008]

By the way, in such a throw-away type tool, since a large cutting resistance acts on the tip 7 which comes into contact with the work material and cuts it, a tool holding the tip 7 is held. It is desirable that the tip portion 2 of the main body 1 be designed so as to have sufficient rigidity. Therefore, in the end mill shown in FIGS. 19 to 21, as described above, the tip pocket 3 is formed such that the thickness of the tip portion 2 gradually increases from the tip of the tool axis C toward the base end side. The tip mounting seat 5 is also a flat surface whose bottom surface 19 is inclined in a direction obliquely intersecting with the tool axis C so that the wall thickness H of the tip portion 2 is gradually increased toward the tool axis C proximal end side. Is molded as.

However, when the chip 7 whose rake face and seating surface are parallel to each other is mounted on the chip mounting seat 5 whose bottom surface 19 is thus inclined, the rake face also corresponds to the chip mounting seat 5. It becomes an inclined surface parallel to the bottom surface 19. That is, when the angle formed by the bottom surface 19 of the tip mounting seat 5 and the tool axis C is θ as shown in FIG. 20,
The absolute value of the axial rake angle γa ₁ of the mounted tip 7 is θ
It becomes unavoidable that the negative angle becomes equal to, and thus the machinability deteriorates.

On the other hand, the radial rake angle γr of the rake face
_When the outer diameter of the tip portion 2 of the tool body ₁ is the same, ₁ is determined by the wall thickness H of the tip portion 2 and the wall thickness of the tip body 8. However, as described above, in order to impart sufficient rigidity to the tip portion 2 of the tool body 1, the wall thickness H of the tip portion 2 cannot be made too small, and considering the rigidity of the tip 7, the tip body is considered. Since it is difficult to reduce the wall thickness of No. 8, the radial rake angle γr ₁
Also has to be increased to the negative side, which leads to further deterioration of the machinability.

In view of the above circumstances, the applicant of the present invention has filed Japanese Patent Application Laid-Open No. 5-50.
We have proposed a throw-away tip as disclosed in No. 317. In this throw-away tip, the top surface of the polygonal shape of the throw-away tip is inclined in a direction in which the thickness becomes smaller as the distance from the nose portion increases. While ensuring the rake angle in the positive direction, the thickness of the tool body is ensured. The present invention further improves this throw-away tip, sufficiently secures a radial rake angle and an axial rake angle without lowering the strength of the tool body to obtain good sharpness, and further, the surface roughness of the work surface. The purpose is to improve.

[0012]

In order to achieve the above object, the invention of claim 1 has a nose portion at a position slightly deviated in the same direction from each corner portion of a square or rectangular chip body. While being formed, in the crossing ridge line formed by one side surface and one end surface of the tip body that is continuous with each nose portion, in the throw-away tip in which cutting edges are formed in succession with each nose portion, the one end surface is,
It has an inclined surface that approaches the other end surface side of the chip body as it separates from each of the nose portions, and the inclined surface inclines toward the other end surface side as it separates from the nose portion. The breaker is formed on the inclined surface along a ridgeline formed by the inclined surface and each of the side surfaces. According to a second aspect of the present invention, in the first aspect, the breaker is configured to be inclined with respect to the cutting edge in a plan view.

[0013]

According to the above construction, the one end surface serving as the rake surface of the tip has the inclined surface toward the other end surface side of the chip body, that is, the seating surface side as the tip rake surface is separated from the nose portion. The rake angle in the axial direction of can be set to a regular angle. Further, also in the cutting edge adjacent to this cutting edge, the radial direction rake angle can be similarly set to a regular angle.

Further, the tip portion of the tool main body for holding the tip can be designed so that the wall thickness gradually increases toward the base end side of the tool axis as in the conventional case, so that the rigidity of this portion is impaired. There is no such thing.
Therefore, according to the present invention, the axial rake angle and the radial rake angle of the rake face are set to the right angle side while maintaining the rigidity of the tip end portion of the tool body that holds the chip with the one end face serving as the rake face of the insert. It is possible to improve the machinability.

In addition, since the breaker is formed along the cutting edge, the rake angle of the cutting edge is set in the positive direction by this breaker, which improves the machinability and the rigidity of the tool body. It gets even bigger. Further, since the valley line of the breaker is inclined with respect to the cutting edge, the distance between the breaker and the cutting edge is optimally set at each position of the cutting edge having different cutting conditions.

[0016]

1 to 5 show an embodiment of the present invention. As shown in these figures, the chip 31 of this embodiment is a positive type chip in which one end surface 33 of the chip body 32, which is the rake face of the chip 31, has a substantially square shape in plan view as shown in FIG. And the nose portions 34, 34 ... Are formed at the corners of this square, respectively. Further, the other end surface 35 of the chip body 32 is a square forming the contour of the chip body 32 (shown by a chain line in FIG. 1).
It is a flat surface that is similar to the square shape, and is a seating surface for the tool body. That is, the chip body 32
Is a rake face 36 by grinding the bottom surface (one end face 33 in the embodiment) of a square truncated pyramid-shaped material having a square cross section (strictly speaking, a square shape with rounded corners). The ridges intersecting with the inclined side surface 37 and the rake surface 36 are cutting edges 38. Further, the rake face 36 is the breaker 3 along the cutting edge 38.
It is a part of 9.

The rake face 36 has the nose portion 34 located at a position slightly deviated from the corner portion of the square formed by the one end face 33 as an apex, and the rake face 36 is separated from the cutting edge 38, and the other end face is formed. The inclined surface gradually approaches 35. Further, the direction of the inclination is inclined with respect to the side of the square formed by the one end surface 33, and as a result, the rake face 3 is separated from the nose portion 34 along the cutting edge 38.
The width of 6 is decreasing. As described above, if the width of the rake face 36 (that is, the width of the breaker) becomes smaller as it goes away from the nose portion, a better chip discharging property can be obtained. That is, in the part where the breaker width is large, the cutting is large, so that the chips are spirally wound and the discharging property becomes poor, and there is a tendency that there is a problem that the chips once discharged are caught by other cutting edges and lead to cutting edge defects. There is. As shown in the drawing, the width of the breaker is reduced as the distance from the nose portion increases, so that the depth of cut is reduced.

The bottom surface 40 of the breaker 39 is a flat surface having a constant width parallel to the other end surface 35, and the nose portion 3
It is inclined so that it approaches the cutting edge 36 as it moves away from 4. As described above, since the bottom surface 40 is flat and the rake surface 36 is inclined both in the cutting edge ridge direction and in the center direction of the tip body, the absolute value of the depth of the breaker 39 is from the nose portion 34. It decreases gradually with distance. Further, the breaker 39 is erected from the bottom surface 40 by the inclined surface 41 so that the one end surface 33
Is connected to the central part of. Further, the inclined surface 41 is adapted to brake chips generated by cutting the cutting blade 38. If the width of the flat bottom surface 40 is large, the radius of the curl of chips is large,
Further, if the width is small, the radius of the curl becomes small. Therefore, by appropriately selecting the depth of cut (breaker width) and the width of the bottom surface 40 in accordance with the use conditions, it is possible to obtain a spiral-shaped chip and obtain a good chip discharge property. In this way, the cut becomes smaller as it goes away from the nose, and the breaker shape is provided with the flat portion, so that, for example, even in a cutting state in which the vertical wall portion is covered above the main cutting edge, it is good. It is possible to improve the surface roughness of the finished surface by obtaining a good chip discharging property.

At the center of the chip body 32, there is a mounting hole 4
2 is provided, and the clamp screw 6 inserted into this
Is fixed to the tool body 1. The periphery of the mounting hole 42 is formed in a cylindrical shape as a whole and has a thickness larger than those of the other portions to ensure the strength of the chip body 32 in this portion.

5 to 8 show a state in which the throw-away tip 31 having the above-mentioned structure is attached to the tip mounting seat 5 in the tip pocket 3 of the tool body 1 of the end mill. In this end mill, a tip pocket 2 is formed in a tip portion 2 of a tool body 1 whose diameter is gradually enlarged toward the tip side in the tool axis C direction, and a bottom surface 4 of the tip pocket 3 in the tool axis C direction tip side. Further, the tip 31 is fixed by a clamp screw 6 to a tip mounting seat 5 formed at a position facing a corner on the side facing the tool rotation direction.

The tip mounting seat 5 has side surfaces 37 that sandwich one nose portion 34 of the tip body 32 when the tip 31 is mounted,
In a state in which 37 is brought into contact with the wall portions 21, 22 of the tip mounting seat 5, respectively, one cutting edge 38 connected to the other nose portion 34 has an outer peripheral surface and a tip surface of the tip portion 2 of the tool body 1, respectively. It is molded in a more protruding shape and size. Further, the wall portions 21 and 22 are set such that the cutting edge 38 on the outer peripheral side is parallel to the axis C of the tool body 1 in the mounted state as shown in FIG. Further, by such attachment, it is possible to secure the perpendicularity of the standing wall portion of the work surface.

At the corner of the tip mounting seat 5 where the walls 21 and 22 intersect, a circular shape in plan view is provided so that the one nose portion 34 does not contact the walls 21 and 22 when the tip 31 is mounted. A recess 20 is formed.

The surface of the tip mounting seat 5 on which the other end surface 35 of the tip body 32 is seated is a flat surface whose thickness gradually decreases from the tip of the tool body 1 toward the base end side. Therefore, in the embodiment shown in FIG.
With respect to one cutting edge 38 whose ridge line is shown in the figure, an axial rake angle larger than the rake angle of the throw-away tip 31 itself is secured while minimizing the decrease in the rigidity of the tool body 1 to obtain the necessary cutting performance. be able to. On the other hand, regarding the other cutting edge 38 whose ridge line is shown in FIG.
A radial rake angle based on the rake angle of the throw-away tip 31 itself can be obtained.

In the indexable end mill having such a structure, the tip 31 is mounted on the tip mounting seat 5 and the clamp screw 6 is tightened, whereby the other end surface 35 of the tip body 32 is pressed against the bottom surface 19 of the tip mounting seat 5. Then, the chip 31 is seated.

It is needless to say that the breaker may have another cross-sectional shape without departing from the scope of the present invention. Further, the throw-away tip may have a rectangular planar shape if necessary. Furthermore, in the above-mentioned one embodiment, the present invention has been described as being applied to a rolling tool such as a throw-away type end mill, but it is needless to say that it can be applied to a bite and a boring bar.

[0026]

As described above, according to the present invention,
As one end face, which is the rake face of the tip, is inclined toward the other end face side of the chip body, that is, the seating face side as it separates from the nose part, this allows the axial rake angle of the tip rake face to be set to a regular angle. can do. Further, also in the cutting edge adjacent to this cutting edge, since the cutting edge is similarly inclined, when one cutting edge is used as the outer peripheral edge, the radial rake angle of the cutting edge as the bottom edge is positive. Can be set to a corner. Further, the tip portion of the tool body that holds this tip can be designed so that its wall thickness gradually increases toward the tool axis base end side as in the conventional case, so that the rigidity of this portion is impaired. There is no such thing. Therefore, according to the present invention, the axial rake angle and the radial rake angle of the rake face are set to the right angle side while maintaining the rigidity of the tip end portion of the tool body that holds the chip with the one end face serving as the rake face of the insert. You can
This can improve the machinability. In addition, since the breaker is formed along the cutting edge, the rake angle of the cutting edge is set in the positive direction by this breaker, which further enhances the action of improving the machinability and the rigidity of the tool body. . Further, since the valley line of the breaker is inclined with respect to the cutting edge, the spacing between the breaker and the cutting edge is optimally set at each position of the cutting edge under different cutting conditions, and therefore each part of the cutting edge is It is possible to exert good chip discharging property in. In addition, the presence of the breaker will set the rake angle of the cutting edge to the more positive side, and it will be possible to easily secure the required rake angle. The rigidity can be increased. In addition, this breaker
A good chip discharging property can be secured.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a side view of an embodiment.

FIG. 3 is a view taken along the line III-III in FIG.

FIG. 4 is a view taken along line VI-VI in FIG.

FIG. 5 is a plan view of a tool to which the throw-away tip of FIG. 1 is attached.

FIG. 6 is a front view of a tool to which the throw-away tip of FIG. 1 is attached.

FIG. 7 is a side view of a tool to which the throw-away tip of FIG. 1 is attached.

FIG. 8 is an enlarged view of a throw-away tip mounting portion in FIG.

FIG. 9 is a plan view showing a case where a conventional tip 7 is mounted on a throw-away type end mill.

10 is a side view of the example of FIG. 9 as viewed from the direction A. FIG.

FIG. 11 is a front view of the example of FIG. 9 as viewed in the B direction.

[Explanation of symbols]

1 Tool body 2 Tip part 5 Tip mounting seat 31, Tip 8,32 Tip body 9,33 One end surface (rake surface) 10,35 Other end surface (seating surface) 11,34 Nose portion 12,13,35 Side surface 16,17 , 38 Cutting edge C Tool axis

Claims (2)

[Claims] 1. A nose portion is formed at a position slightly deviated in the same direction from each corner of a square or rectangular chip body, and the nose portion is connected to one side surface of the chip body connected to each nose portion. At the intersecting ridgeline formed by the end face,
In a throw-away tip in which cutting edges are formed in succession with the respective nose portions, the one end surface has an inclined surface that approaches the other end surface side of the tip body as it separates from each of the nose portions, By this inclined surface, the intersecting ridge line is inclined toward the other end surface side as it is separated from the nose portion, and the inclined surface is along the ridge line formed by these inclined surface and each of the side surfaces. A throw-away tip characterized by having a breaker. 2. The throw-away tip according to claim 1, wherein the breaker is inclined with respect to the cutting edge in a plan view.