JPH11320217A - Throwaway tip for machining inside diameter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a throwaway tip which can machine an inside diameter smaller than 5 mm. SOLUTION: A projection 3 is protruded in a single piece from the side of a part for clamp to be fixed to a shank 21, and a cutter tip 6 for bore machining is installed on one side of the forefront of the projection 3. The part for clamp is formed as capable of being clamped to a tip seat 22 in a conventional throw-away cutting tool for bore machining and is arranged so as to suit small diametric bore machining which requires projection 3 fitted with cutter tip.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an indexable insert for internal diameter machining, and more particularly, to an indexable insert for internal diameter machining (hereinafter, indexable insert) used for internal diameter (inner peripheral surface) machining such as boring. Or simply referred to as chips).

[0002]

2. Description of the Related Art Conventionally, a tool or a boring bar (hereinafter, also referred to as a bar) is used for boring a bore or the like, and these are roughly classified into a solid type and a throw-away type. Solid type blades have a high degree of freedom in the size of the cutting blade because the blade is formed by grinding or polishing a steel material (such as machine tool steel), so-called sharpening. Even a cutting blade used for machining a small inner diameter of about 3 to 5 mm can be manufactured relatively easily. However, since the cutting edge is formed by sharpening, the disadvantage is that the cost is increased. Further, in the formation of the cutting edge by such sharpening, for example, it is not easy to form a chip breaker having a convex shape (bulge shape), and there is a problem in improving the chip disposal (discharge) property. Further, such a solid type is disadvantageous in that the cutting blade position is likely to be out of order when the cutting tool or the bar is replaced, so that it takes time to set up such a position.

On the other hand, a throw-away type is usually made of a super hard tool material such as a cemented carbide and can be manufactured by press-forming and sintering a raw material powder. It has a high degree of freedom in shape, and can be manufactured at relatively low cost. The tip is provided with a tip seat (pocket) for tip attachment (pocket) and is clamped (fixed) to the tip seat of a shank or a bar. .

[0004]

However, with a cutting tool or a boring bar using such a throw-away tip, it is usually difficult to machine an inner diameter of less than 5 mm. This is because, for example, in order to perform inner diameter processing to some extent such as boring, the processing cannot be performed unless a chip to be used falls within the inner diameter. In this case, if the tip is of the screw clamp type, it is difficult to make the maximum width of the rake face of the tip less than 5 mm in consideration of the diameter of the through hole for the screw clamp and the necessary thickness of the periphery thereof. That's why. That is, if it is less than this, the diameter of the screw used for the clamp becomes too small, and the strength of the cutting tool becomes insufficient such that a clamp with appropriate strength cannot be obtained.
Also, in the clamp-on method that clamps (or pulls) the chip between the clamp pieces,
A diameter of about 10 mm is the minimum limit of the inner diameter machining. Therefore, when machining an inner diameter of less than φ5 mm,
The fact was that the solid type had to be used.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a throw-away insert capable of machining an inner diameter of less than φ5 mm, which has been difficult with a conventional throw-away insert. Is to provide.

[0006]

In order to solve the above-mentioned problems, an inside diameter machining indexable insert according to the present invention includes a clamping portion and at least one projection projecting integrally from the clamping portion. That is, a cutting blade is provided at the tip of the protruding portion or at one side in the vicinity thereof. Here, the clamping portion is a portion for clamping the inner diameter processing throwaway tip to a shank or a boring bar, and includes a through hole for a screw clamp and a piece receiving portion for clamping with a clamp piece. Refers to the part provided with

According to the present invention, as in the above-described means, the cutting edge (blade edge) responsible for the inner diameter machining, that is, the cutting edge that enters the inner diameter of the work is integrated with the clamp portion, but the tip of the protruding portion or the protruding portion protruding from the clamped portion. It is provided on one side in the vicinity. Therefore, the projection with the cutting edge can be formed to have a thickness that can be within the desired small-diameter processing inner diameter without considering the clamp. That is, by setting the thickness (width and thickness) of the protruding portion in accordance with the inner diameter of the object to be processed, the diameter of the protruding portion depends on the protruding length of the protruding portion with the cutting blade provided on one side thereof. Internal diameter processing such as boring of φ2 to less than 5 mm (hereinafter also referred to as small diameter) can be performed.

In addition, since it is not necessary to consider the inside of the inner diameter in the inner diameter processing, the clamp portion can be formed to a size necessary for the clamp irrespective of this, so that the clamping strength is a problem. It won't be. That is, even when a through hole for a screw clamp is provided, it is not necessary to make it smaller than that of a chip having a size of, for example, about □ 8 mm. It is good. Therefore, by forming the clamping portion so that it can be clamped to the tip seat of the conventional throw-away bite for internal diameter processing, it is possible to perform clamping and small-diameter internal diameter processing as in the conventional case.

In addition, the indexable insert for inner diameter machining according to the present invention can be made of cemented carbide, cermet,
It can be formed of a super hard tool material such as ceramic. That is, since the raw material powder can be formed by press-molding and sintering or firing, the rake face of the cutting edge has a convex or concave shape, or an appropriate three-dimensional chip made of a combination thereof, as in the conventional case. A breaker can be formed without any problem. Thus, it is possible to provide an indexable insert for internal diameter machining that can perform small-diameter internal diameter machining without impairing the chip disposability.

[0010] The clamping portion may be any portion as long as it can be clamped without impairing the clamping strength. Therefore, its planar shape and the like may be arbitrary. In order to use a shank or bar that can be used, it is preferable that the chip is formed in a substantially polygonal plate shape such as a square or a rectangle similar to the planar shape of a conventional chip. Further, the clamp to the shank or the bar may be of the clamp-on type or the screw type, but it is preferable to use the screw type because of the simplicity of the structure. Therefore, the clamp penetrates through the clamp portion in the thickness direction. It is preferable to provide a through hole for a screw clamp. In the above-mentioned means, if a plurality of protrusions provided with cutting edges are provided, a plurality of cutting blades can be provided by one chip. In this case, the protrusions are provided point-symmetrically when viewed from the rake face side. Good.

Further, in the present invention, the length (projection amount) of the projecting portion affects the boring depth, and this length is set to such an extent that the projecting portion does not bend or chatter. May be set in consideration of the thickness (width or thickness) of the object. If the protrusion amount is large, the rod shape is formed, and if the protrusion amount is short, the protrusion is formed. The rake face of the cutting blade may be provided with a convex or concave chip breaker, if necessary.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of such a throw-away insert for inner diameter machining will be described with reference to FIGS.
This will be described in detail with reference to FIG. In the drawing, reference numeral 1 denotes a throw-away tip for inner diameter machining of the present example, which is made of, for example, a cemented carbide and has a substantially rectangular plate-like clamping portion 2 having two sides of 12 mm and 8 mm and a thickness of 2.38 mm. And a bar-shaped protrusion 3 protruding along a side of a predetermined length L with a constant width W (for example, 3.5 mm) for a minimum processing inner diameter, for example, φ4 mm. However, the tip surface 3 of the projection 3
The shape or cross-sectional shape viewed from the side a (viewed from the arrow A in FIG. 1) is substantially semicircular with the rake face 4 as a chord, and the rake face 4 and the main face 5 of the clamping portion 2 are formed. Is the same in this example. The radius of the cross section of the protrusion 3 is set to be smaller than the plate thickness of the clamping portion 2, for example, 1.5 mm. A boring cutting edge (blade edge) 6 is formed at the tip of the protruding portion 3 or at one side in the vicinity thereof so as to slightly protrude in a V-shape. In addition, the clamp portion 2 is provided with a through hole 7 for screw clamp which penetrates in the thickness direction, and the peripheral edge on the rake face 4 side is rough to form a tapered face 8. The through hole 7 has a diameter of 4.6 mm so that the inside diameter of the through hole 7 can insert a screw (for example, M4) having sufficient strength for the clamp.

On the other hand, such a tip 1 is used by being clamped to a tip seat 22 at the tip of a shank (hereinafter also referred to as a square shank) 21 having a rectangular cross section shown in FIGS. The square shank 21 is suitable for being used for inner diameter machining by being fixed to a comb-type tool post in an automatic lathe of a type in which a guide bush supports an end of a work, and has a relatively small outer diameter (for example, It is used for processing a few mm inner diameter on a round bar (work) of φ10 mm or less. That is, the angular shank 21 is provided with an offset portion 23 at the tip thereof, and the offset portion 23 has a chip seat 22 (pocket) having a screw hole 24 substantially identical to a plan view thereof for clamping the clamping portion 2 of the chip 1 in plan view. Has been established. Then, as shown in FIG.
2 is mounted on the chip 1 and clamped with a set screw 25 to form a boring tool, which is fixed to a comb-type tool post (not shown) to fix a work (2 in FIG. 4). Boring 30 (indicated by the dashed line) is performed. In this example, the protrusion T of the cutting blade 6 from the reference plane K of the shank 21 is +
The opening end of the work 30 that traverses in the coaxial direction while rotating about the rotation axis G is set to be within 1 mm and within −2 mm. (Space) H.

In such machining, the indexable insert 1 for inside diameter machining of this embodiment has no relation to the projection 3,
Since the clamping portion 2 is clamped by the set screw 25 in the wide flat clamping portion 2 like a chip of a normal size so as to exhibit sufficient clamping strength, there is no problem (insufficient) in clamping strength. Then, in the boring operation, the projection portion 3 having a small width is used without inserting the clamped portion 2 for clamping into the processing inner diameter (in the prepared hole) of the work 30.
It can be cut by putting only the same inside diameter. Therefore, in the present example, boring of a small diameter of about 4 mm can be performed to a depth of approximately the length L of the protrusion 3.

In this embodiment, since the shape and the cross-sectional shape of the protrusion 3 as viewed from the front end face 3a are substantially semicircular, the strength of the protrusion 3 can be effectively reduced without adversely affecting the chip controllability. Can hold. However, as shown in FIG. 5, the cross-sectional shape of the protruding portion may be a 1/4 circular cross-sectional shape over the entire length L of the protruding portion 3 in consideration of its strength and chip handling properties, or as shown in FIG. In the case where the boring depth is shallow and there is no problem in chip handling, as in the case of the protruding portion 3, it may be appropriately set such as to have a substantially circular cross-sectional shape except for the rake face 4 (near the cutting edge 6). The same parts as those in FIG. 1 in the chip 1 in FIGS. 5 and 6 are denoted by the same reference numerals.

A cutting blade 6 used for boring as shown in FIG.
As shown in FIGS. 7 and 8, the chip 1 provided with the chip breaker 4a having a convex shape (elevated shape) on the rake face 4 if necessary in accordance with cutting conditions (such as chip disposability). ,
Alternatively, a concave chip breaker 4b may be provided.
The length of the projecting portion 3 of such a chip may be set according to the boring depth.
What is necessary is just to set suitably according to a processing inside diameter (boring diameter).
Note that the length of the protruding portion may be appropriately set in a range in which bending or chattering does not occur, in consideration of the thickness, the cross-sectional shape, the material of the work, and the like.

In the above-described embodiment, the insert 1 having the boring cutting edge 6 has been described. However, the shape of the cutting blade may be appropriately set according to the type of inner diameter machining. For example, when used for grooving the inner diameter, the (blank) shape of the cutting blade 6 may be set to the shape of the groove as shown in FIG. As shown, the cutting blade 6 may have a (planar) shape that matches the thread. Further, in the case of using for the step processing of the inner diameter, the cutting edge 6 may have a (planar) shape as shown in FIG. Note that the chip 1 shown in FIGS.
The same parts as those in FIG. 1 are denoted by the same reference numerals.

In each of the above-described embodiments, a single protruding portion provided with a cutting edge (a protruding portion with a cutting edge) is exemplified.
In the present invention, the number is not limited to this, and two or more can be provided. FIG. 12 shows an example of such a chip 11 in which two projecting portions 3 with the same cutting edges 6 as those in FIG. 1 are provided in a point-symmetric manner. . In such a case, a relief (concave portion) 26 is formed in the tip seat 22 of the shank 21 so that the projecting portion 3 with the cutting blade 6 that is not used is accommodated.

The shank for clamping the tip is
What is necessary is just to use an appropriate thing according to the conditions of attachment to a tool post, etc. Naturally, it is not limited to what was illustrated in the above-mentioned form, and peripheral turning, such as a shank 31 as shown in FIG. For example, the tip 1 can be used with the protruding portion 3 protruding along the longitudinal direction of the shank 31.

In the above-mentioned embodiment, since the clamp of the tip 1 to the shank is screw-fastened, the through hole 7 is provided. However, although not shown, the clamp to the shank is a clamp-on type using a clamp piece. In such a case, it is sufficient to provide a piece receiving portion (recess) corresponding to the clamp piece on the main surface of the portion for clamping without a hole or if necessary.
The planar shape of the clamp portion is substantially rectangular in the above embodiment, but may be an appropriate shape such as a square. Further, in the above-described embodiment, the protruding portions are protruded along the side surfaces (sides) of the clamping portion, but it is clear that the protruding position (region) is not limited to this. That is, it is apparent that the shape of the indexable insert for inside diameter machining according to the present invention can be changed from the above-described form as appropriate and practically used without departing from the gist thereof.

The above-described indexable insert for internal diameter machining 1 of the present invention described above can also be similarly clamped on a boring bar used by being set on a tailstock of a lathe or a boring machine. Can be used for processing. In other words, it is clear that the same effect as in the above embodiment can be obtained when used as a boring bar.

FIGS. 14 and 15 show such an example. In the figure, the chip 1 is clamped in the same manner as described above on a rectangular chip seat 22 formed at the tip of a bar 41 having a substantially circular cross section, instead of a square bite shank. Since there is no difference from the chip 1 including the function and effect except that the protruding portion 3 protruding from the clamping portion 2 is protruded along one side of the opposite side, the same portion includes: The same reference numerals are used.

In this case, if necessary, a chip breaker may be provided in the same manner as described above, and an appropriate cutting edge may be formed according to the processing. Further, in the implementation, such as a plurality of blades may be appropriately designed according to the processing conditions.

[0024]

As is apparent from the above description, according to the indexable insert for inner diameter machining according to the present invention, the diameter of φ5 mm, which has been considered to be difficult to process with the conventional indexable insert, without lowering the clamping strength. It is possible to realize inner diameter processing with a small diameter such as less than. In addition, a clamping part is formed so that it can be clamped to the insert seat of a conventional inner diameter machining throw-away tool or boring bar, and a projection with a cutting edge is formed so as to be suitable for the required small-diameter machining. By forming it, a desired small-diameter inner diameter can be machined with a conventional shank or boring bar.

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment of a throwaway tip for inner diameter machining according to the present invention.

FIG. 2 is a partially broken cross-sectional view of the throw-away tip shown in FIG.

FIG. 3 is a perspective view of an example of a shank for clamping the tip of FIG. 1;

FIG. 4 is a plan view of a main part in which the tip of FIG. 1 is clamped to the shank of FIG. 3;

FIG. 5 is a perspective view of another example of a throw-away tip according to the present invention.

FIG. 6 is a perspective view of another embodiment of a throw-away tip according to the present invention.

FIG. 7 is a perspective view of a main part of another embodiment of a throw-away tip according to the present invention.

FIG. 8 is a perspective view of a main part of another embodiment of a throw-away tip according to the present invention.

FIG. 9 is a plan view of another embodiment of a throw-away tip according to the present invention.

FIG. 10 is a plan view of another embodiment of a throw-away tip according to the present invention.

FIG. 11 is a plan view of another embodiment of a throw-away tip according to the present invention.

FIG. 12 is a plan view of another embodiment of a throw-away tip according to the present invention.

FIG. 13 is a plan view in which the indexable insert of FIG. 1 is clamped to another shank.

FIG. 14 is a plan view of another embodiment of a throw-away tip according to the present invention.

FIG. 15 is a view of the throw away tip of FIG. 14 as viewed from the direction of arrow A.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 indexable insert for inner diameter machining 2 clamp portion 3 protrusion 6 cutting blade 7 through hole for screw clamp 21, 31, 41 shank

Claims (3)

[Claims] A clamp portion and at least one protrusion integrally projecting from the clamp portion;
A cutting insert for internal diameter machining, wherein a cutting blade is provided at a tip of the protruding portion or at one side in the vicinity thereof. 2. The indexable insert for internal diameter machining according to claim 1, wherein the clamping portion has a substantially polygonal plate shape. 3. The indexable insert for internal diameter machining according to claim 1, wherein a through hole for a screw clamp penetrating in the thickness direction is provided in the clamp portion.