JP4172156B2 - Throwaway tip - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a throw-away tip that is attached to a tip mounting seat provided in a tool body by a clamp screw, particularly a positive tip.
[0002]
[Prior art]
Conventional throw-away chips (hereinafter simply referred to as chips) have various shapes depending on the application. Hereinafter, as an example, a chip 31 having a substantially parallelogram flat plate shape will be described with reference to FIGS. 4 and 5. 4 is a plan view of the chip 31, and FIG. 5 is a cross-sectional view taken along the line BB in FIG.
The chip 31 has a substantially parallelogram flat plate shape including a lower surface 32 that forms a seating surface, a flank 33 that is a peripheral surface that rises upward from the lower surface 32, and an upper surface 34 that is formed at the upper end of the flank 33. A cutting edge 36 is formed at the intersecting ridge line portion between the flank 33 and the upper surface 34. The tip 31 is a positive tip that is inclined to the outside and rises as the flank 33 moves upward from the lower surface 32.
The tip 31 is formed with a screw insertion hole 38 extending from the center of the upper surface 34 to the lower surface 32, and the two adjacent surfaces of the lower surface 32 and the flank 33 are abutted against the tip mounting seat of the tool body. In the state of contact, the tool body is mounted by a clamp screw inserted through the screw insertion hole 38.
The screw insertion hole 38 is provided with a counterbore 38a for receiving the head of the clamp screw on the upper surface 34 side, and a portion located below the counterbore 38a has an inner diameter narrower than the counterbore 38a. And it is set as the straight hole part 38b which is the same internal diameter D over the full length.
[0003]
This tip is mounted on a tool body and used as a cutting blade of a cutting tool such as a cutting tool or a turning tool such as a milling cutter. Below, the case where this chip | tip 31 is used as a cutting blade of a cutting tool is demonstrated as an example.
The tool body 41 to which the tip 31 is mounted has, for example, a substantially quadrangular prism shape, and as shown in the longitudinal sectional view of FIG. 6, the tip of one of the peripheral surfaces (this is referred to as the upper surface 42) A concave portion having a substantially parallelogram shape is formed at the corner portion to form a chip mounting seat 43.
The chip mounting seat 43 has a substantially parallelogram-shaped bottom surface 43a and two side walls 43b (only one is shown in FIG. 6) that stand up from the bottom surface 43a and intersect each other. Here, like the flank 33 in the tip 31, the side wall 43 b is inclined to the outside of the tip mounting seat 43 as it goes upward from the bottom surface 43 a. Further, a thin portion is formed at the intersection of the two side walls 43b, and the bottom surface 43a is a flat surface extending to the thin portion.
Further, the chip mounting seat 43 is formed with a main body insertion hole 47 into which the clamp screw 46 is inserted on the bottom surface 43a so as to be substantially coaxial with the screw insertion hole 38 of the mounted chip 31.
[0004]
The chip 31 has a lower surface 32 in surface contact with the bottom surface 43 a of the chip mounting seat 43 and two adjacent relief surfaces 33 in surface contact with the two side walls 43 b of the chip mounting seat 43. Then, the clamp screw 46 inserted through the screw insertion hole 38 is screwed into the main body insertion hole 47 so that the tool main body 41 is mounted.
Here, the main body insertion hole 47 formed in the bottom surface 43a of the chip mounting seat 43 is provided slightly eccentric to the side wall 43b side from the position coaxial with the screw insertion hole 38 of the chip 31 in the mounted state. When the chip 31 is mounted, the clamp screw 46 is eccentric to the side wall 43b in the screw insertion hole 38 of the chip 31 (in FIG. 6, the axis of the screw insertion hole 38 is O1, the main body insertion hole 47 axes are indicated by O2). Thus, in a state where the chip 31 is mounted on the chip mounting seat 43, the chip 31 is pressed not only on the bottom surface 43a but also on the side wall 43b by being pressed by the head 46a of the clamp screw 46, and the chip 31 is pressed against the chip mounting seat. It is firmly fixed to 43.
[0005]
[Problems to be solved by the invention]
However, when the main body insertion hole 47 of the chip mounting seat 43 is provided eccentrically with respect to the screw insertion hole 38 of the chip 31 in the mounted state, the chip 31 is mounted on the chip mounting seat 43. In this case, the gap formed between the shaft portion 46b of the clamp screw 46 and the inner surface of the straight hole portion 38b of the screw insertion hole 38 of the chip 31 is reduced, and the shaft portion 46b of the clamp screw 46 is changed to the straight hole portion 38b of the chip 31. It is easy to interfere with the inner surface.
On the other hand, the chip 31 is a positive chip. When the chip 31 is mounted on the chip mounting seat 43, the chip is not in surface contact with the bottom surface 43 a and the side wall 43 b of the chip mounting seat 43. Therefore, when the shaft portion 46b of the clamp screw 46 interferes with the straight hole portion 38b of the chip 31 when the chip 31 is mounted on the chip mounting seat 43, the chip 31 has a structure as shown in FIG. The side wall 43b side of the chip mounting seat 43 is mounted in a state of floating from the bottom surface 43a, or the entire chip 31 is mounted in a state of floating from the bottom surface 43a of the chip mounting seat 43 as shown in FIG. Sometimes.
[0006]
The present invention has been made in view of the above circumstances, and an object thereof is to provide a chip in which interference of a clamp screw with a screw insertion hole when mounted on a chip mounting seat is reduced.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a chip of the present invention includes a lower surface that forms a seating surface, a flank that is a peripheral surface that rises and inclines outward from the lower surface, and an upper surface that faces the lower surface. This is a throw-away tip that has a substantially flat plate shape, the cross ridge line portion of the flank and the top surface is a positive tip that constitutes a cutting blade, and is attached to a tip mounting seat provided on the tool body by a clamp screw. Te, wherein is formed by a through screw insertion hole the clamping screw is inserted to the lower surface from the upper surface, in the screw insertion hole, receiving the head of the clamping screw on the upper side, the screw insertion gradually as containing the axis of the bore cross-section Ruzaguri be reduced in diameter it is provided so as to form a convex curve, and the lower surface side, smoothly continuous with the convex curve downward It is characterized in that the enlarged diameter portion of substantially conical shape which is the diameter are provided.
[0008]
In the chip configured as described above, a conical surface-shaped expanded portion that gradually increases in diameter as it goes downward is provided on the lower surface side of the screw insertion hole. For this reason, even when the main body insertion hole of the chip mounting seat is provided eccentrically with respect to the screw insertion hole of the chip in the mounted state, when mounting the chip on the chip mounting seat, the shaft portion of the clamp screw and the chip A clearance between the inner surface of the enlarged diameter portion of the screw insertion hole is secured, and the shaft portion of the clamp screw is less likely to interfere with the inner surface of the enlarged diameter portion of the chip. Further, the counterbore is reduced in diameter so as to form a convex curve in a cross section including the axis of the screw insertion hole, and a diameter-expanded portion smoothly connected to the convex curve is formed by gradually increasing the diameter toward the lower side. Therefore, the wall thickness of the spot face can be sufficiently secured, and the strength is increased.
[0009]
Here, when the angle formed between the inner wall surfaces facing each other across the axis of the screw insertion hole on the inner wall surface of the enlarged diameter portion is smaller than, for example, 1 °, when the chip is mounted on the chip mounting seat, A sufficient gap cannot be secured between the shaft portion and the inner surface of the enlarged diameter portion of the screw insertion hole of the chip, and the shaft portion of the clamp screw easily interferes with the inner surface of the enlarged diameter portion of the chip. When this angle is larger than 60 °, for example, the wall thickness of the counterbore portion of the screw insertion hole cannot be sufficiently secured, and the strength of this portion is lowered. For this reason, it is desirable that the angle formed by the inner wall surfaces facing each other across the axis of the screw insertion hole on the inner wall surface of the enlarged diameter portion is within a range of 1 ° to 60 °.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a chip according to the present invention will be described with reference to FIGS. FIG. 1 is a plan view showing the shape of a chip according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line AA in FIG.
The chip 1 shown in this embodiment includes, for example, a lower surface 2 that forms a seating surface, a flank 3 that is a peripheral surface that rises upward from the lower surface 2, and an upper surface 4 that is formed at the upper end of the flank 3. A parallelogram flat plate shape is formed, and a cutting edge 6 is formed at an intersecting ridge line portion between the flank 3 and the upper surface 4. The tip 1 is a positive tip that is tilted outward as the flank 3 moves upward from the lower surface 2.
A screw insertion hole 8 extending from the center of the upper surface 4 to the lower surface 2 is formed in the chip 1, and two adjacent surfaces of the lower surface 2 and the flank 3 are made to contact the chip mounting seat of the tool body. In the state of contact, the tool body is mounted by a clamp screw inserted through the screw insertion hole 8.
[0011]
The screw insertion hole 8 is provided with a counterbore 8a for receiving the head of the clamp screw on the upper surface 4 side, and on the lower surface 2 side, a conical surface-shaped expanded portion that gradually increases in diameter as it goes downward. 8b is provided. Here, the counterbore 8a has a constant inner diameter on the upper surface 4 side, and the lower surface 2 side is reduced in diameter so as to form a convex curve in a cross section including the axis O of the screw insertion hole 8. The diameter portion 8b is also formed so as to expand the diameter at a constant angle smoothly and continuously on the convex curve in the cross section including the axis O.
Further, the angle θ formed by the inner wall surfaces facing each other across the axis O of the screw insertion hole 8 on the inner wall surface of the enlarged diameter portion 8b is in the range of 1 ° to 60 °.
[0012]
The chip 1 configured as described above is mounted on a tool body in the same manner as the conventional chip 31 and used as a cutting tool of a cutting tool such as a cutting tool or a turning tool such as a milling cutter. Below, the case where this chip | tip 1 is used as a cutting blade of a cutting tool is demonstrated as an example.
As described above, the tool body 41 to which the chip 1 is mounted has, for example, a substantially quadrangular prism shape. As shown in FIG. 3, one of the peripheral surfaces (this is referred to as the upper surface 42). A substantially square-shaped recess is formed at the tip corner to form a chip mounting seat 43.
The chip mounting seat 43 has a substantially rectangular bottom surface 43a, and two side walls 43b (only one is shown in FIG. 3) that stand from the bottom surface 43a and intersect each other. Here, like the flank 3 in the chip 1, the side wall 43 b is inclined to the outside of the chip mounting seat 43 as it goes upward from the bottom surface 43 a. Further, a thin portion is formed at the intersection of the two side walls 43b, and the bottom surface 43a is a flat surface extending to the thin portion.
Further, the chip mounting seat 43 is formed with a main body insertion hole 47 into which the clamp screw 46 is inserted on the bottom surface 43a so as to be substantially coaxial with the screw insertion hole 8 of the mounted chip 1.
[0013]
The chip 1 has its lower surface 2 in surface contact with the bottom surface 43 a of the chip mounting seat 43 and two adjacent relief surfaces 3 in surface contact with the two side walls 43 b of the chip mounting seat 43. Then, the clamp screw 46 inserted through the screw insertion hole 8 is screwed into the main body insertion hole 47 so that the tool body 41 is mounted.
Here, the main body insertion hole 47 formed in the bottom surface 43a of the chip mounting seat 43 is provided slightly eccentric to the side wall 43b side from a position coaxial with the screw insertion hole 8 of the chip 1 in the mounted state. When the chip 1 is mounted, the clamp screw 46 is eccentric to the side wall 43b in the screw insertion hole 8 of the chip 1 (the axis of the main body insertion hole 47 is indicated by O2 in FIG. 3).
[0014]
In the chip 1 configured as described above, a conical surface-shaped diameter-enlarged portion 8 b that gradually increases in diameter as it goes downward is provided on the lower surface side of the screw insertion hole 8. For this reason, when the chip 1 is mounted on the chip mounting seat 43, a gap C is secured between the shaft portion 46 b of the clamp screw 46 and the inner surface of the enlarged diameter portion 8 b of the screw insertion hole 8 of the chip 1. The shaft portion 46b is less likely to interfere with the inner surface of the enlarged diameter portion 8b of the chip 1.
[0015]
According to the chip 1 configured in this way, when the chip 1 is mounted on the chip mounting seat 43, the shaft portion 46b of the clamp screw 46 is unlikely to interfere with the inner surface of the enlarged diameter portion 8b of the chip. It can be appropriately mounted on the mounting seat 43. For this reason, it is possible to prevent the chip 1 from being lifted up, prevent rattling during cutting, and perform stable and smooth cutting.
[0016]
Here, when the angle θ between the inner wall surfaces facing each other across the axis O of the screw insertion hole 8 on the inner wall surface of the enlarged diameter portion 8b is smaller than 1 °, for example, the chip 1 is mounted on the chip mounting seat 43. In this case, a sufficient gap C between the shaft portion 46b of the clamp screw 46 and the inner surface of the enlarged diameter portion 8b of the screw insertion hole 8 of the chip 1 cannot be secured. It becomes easy to interfere with the inner surface of the enlarged diameter portion 8b. When this angle is larger than 60 °, for example, the wall thickness of the counterbore portion 8a of the screw insertion hole 8 cannot be sufficiently secured, and the strength of this portion is lowered. For this reason, it is desirable that the angle formed by the inner wall surfaces facing each other across the axis O of the screw insertion hole 8 on the inner wall surface of the enlarged diameter portion 8b is in the range of 1 ° to 60 °.
[0017]
In the above embodiment, an example in which the chip 1 has a substantially parallelogram flat plate shape is shown. However, the shape is arbitrary, for example, other rectangular flat plate shape, polygonal flat plate shape, or substantially circular plate. It is good also as a shape.
Moreover, although the example which used the chip | tip 1 as a cutting blade of a cutting tool was shown in the said embodiment, it is not restricted to this, The chip | tip 1 is a chip | tip with a clamp screw with respect to the chip | tip mounting seat provided in a tool main body. If it is the structure which mounts | wears, you may use for cutting tools other than a cutting tool, and turning tools, such as a milling machine.
[0018]
【The invention's effect】
According to the chip of the present invention, the conical surface-shaped enlarged portion that gradually increases in diameter as it goes downward is provided on the lower surface side of the screw insertion hole. A clearance is secured between the shaft of the clamp screw and the inner surface of the enlarged diameter portion of the screw insertion hole of the chip, and the shaft of the clamp screw is less likely to interfere with the inner surface of the enlarged diameter portion of the chip, so that the chip is attached to the chip mounting seat. Can be properly mounted. For this reason, it is possible to prevent chips from being lifted, to prevent rattling during cutting, and to perform stable and smooth cutting. Further, the counterbore is reduced in diameter so as to form a convex curve in a cross section including the axis of the screw insertion hole, and a diameter-expanded portion smoothly connected to the convex curve is formed by gradually increasing the diameter toward the lower side. Therefore, the wall thickness of the spot face can be sufficiently secured, and the strength is increased.
[0019]
When the chip is mounted on the chip mounting seat, the angle formed by the inner wall surfaces facing each other across the axis of the screw insertion hole on the inner wall surface of the enlarged diameter portion is within a range of, for example, 1 ° to 60 °. In this case, it is possible to sufficiently secure the wall thickness of the counterbore portion of the screw insertion hole while sufficiently securing a gap between the shaft portion of the clamp screw and the inner surface of the enlarged diameter portion of the screw insertion hole of the chip.
[Brief description of the drawings]
FIG. 1 is a plan view showing a shape of a chip according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the chip shown in FIG.
FIG. 3 is a longitudinal sectional view showing a state in which a chip according to an embodiment of the present invention is mounted on a tool body.
FIG. 4 is a plan view showing the shape of a conventional chip.
5 is a cross-sectional view of the chip shown in FIG. 4 taken along the line BB.
FIG. 6 is a longitudinal sectional view showing a state where a conventional chip is mounted on a tool body.
FIG. 7 is a longitudinal sectional view showing an example of a mounting failure that occurs when a conventional chip is mounted on a tool body.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tip 2 Lower surface 3 Flank 4 Upper surface 6 Cutting edge 8 Screw insertion hole 8a Counterbore 8b Diameter expansion part 41 Tool main body 43 Tip mounting seat 46 Clamp screw

Claims (2)

It has a substantially flat plate shape having a lower surface that forms a seating surface, a flank that is a peripheral surface that rises outwardly from the lower surface, and an upper surface that faces the lower surface. A throw-away tip that is attached to the tip mounting seat provided on the tool body by a clamp screw, with the cross ridge line portion being a positive tip constituting the cutting blade,
A screw insertion hole through which the clamp screw is inserted is formed to penetrate from the upper surface to the lower surface,
In the screw insertion hole, wherein the upper surface side receive the head of the clamping screw, said Ruzaguri section containing the axis of the screw insertion hole is reduced in diameter so as to form a convex curve is provided, and wherein A throw-away tip having a substantially conical surface-shaped enlarged portion which is smoothly continuous with the convex curve and gradually increases in diameter toward the lower side on the lower surface side.   2. The throw according to claim 1, wherein an angle formed between inner wall surfaces facing each other across an axis of the screw insertion hole on an inner wall surface of the enlarged diameter portion is within a range of 1 ° to 60 °. Away tip.

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