JPH10291116A - Throw-away type turning cutting tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the frequency of resharpening of a cutting edge by regrinding a turning cutting tool structured to holdingly support a plate-like throw-away tip inserted into a straight-lined slit on the tip of a holder by means of the two-slit part of the tip part of the holder. SOLUTION: On tip-holding faces 3a, 3b made up of two opposing faces of a slit 3, and on one face or both faces of a throw-away tip 1 put between the tip-holding faces, irregular steps 9 parallel to the tool axis which longitudinally on these faces, are provided corresponding to each other. Further, a tip mounting hole 8 for receiving clamping members 6, 7 is formed into a slot extending along the direction of the tool axis to maintain the position accuracy of the tip 1 in the radial direction of the tool by the steps 9, and to move the tip 1 in the direction of the tool axis in the range of gap produced between the clamping member 7 and the mounting hole 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throw-away type milling machine such as a throw-away type end mill, a throw-away type reamer, a throw-away type drill, etc., in which the number of times of re-grinding of the cutting edge is increased to improve the economic effect. For tools.

[0002]

2. Description of the Related Art A well-known milling tool is provided with a single-letter slit at the tip of a holder for vertically dividing the part into two parts, and the slit is formed into a plate-like throw-away chip (hereinafter simply referred to as a chip). In some cases, the tip is inserted between two halves of the main body, and the cutting is performed with a cutting edge symmetrical about the center of rotation attached to the tip. 6
No. 53012, JP-A-8-281513 and JP-A-8-294814 disclose such tools.

A tool having such a structure is suitable for high-precision machining, but is disadvantageous in that the chip unit price is higher than a tool using a combination of a plurality of chips. Therefore, although effective use of the chip is desired, there is hardly any end mill or reamer having the same structure in the related art in which cutting edges are re-ground.

[0004] Some drills have the same structure but have a large amount of tip protrusion from the tip of the holder. In this case, re-polishing can be performed using a portion where the tip protrudes excessively as a polishing allowance.

[0005]

The end mill and the reamer can be reground as long as the tip protrudes from the holder tip, as in the case of the above-mentioned drill. However, there is a limit to the amount by which the tip can protrude from the tip of the holder, and therefore, even if re-polishing can be performed, the number of conventional tools that cannot change the fixing position of the tip is very small.

An object of the present invention is to increase the number of re-polishing of the cutting blade in order to further increase the economic effect of the tool having the above structure.

[0007]

In order to solve the above-mentioned problems, according to the present invention, a one-letter slit is provided at the tip of a holder, and a plate-like throw-away tip is inserted into the slit, and the holder is formed by the slit. In a throw-away type milling tool in which a halved portion at a tip is fastened in a direction in which a slit is sandwiched by a fastening member and the throw-away tip is sandwiched by the halved portion, a tip holding surface of the halved portion is provided. On one or both sides of the throw-away insert sandwiched between the surfaces, a corresponding uneven step parallel to the tool axis for vertically cutting those surfaces is provided, and further, a mounting hole for the throw-away insert through which the fastening member is inserted. Is made a long hole in the tool axis direction.

When the tool is applied with the re-ground abrasive insert, it is desirable to fill the gap formed between the rear end face of the slit and the back surface of the insert away with an adjust piece.

[0009] Further, a first fastening member for pulling the fastening member to the split portion and a second fastening member for directly fastening the throw-away tip to one of the split portions are provided. It is also preferable that the second tightening member is brought into contact with the entrance chamfer of the mounting hole, and the second tightening member is tightened obliquely rearward.

[0010]

According to the present invention, there is a gap between the mounting hole of the long hole provided in the chip and the fastening member, and the chip can be moved in the axial direction of the tool within the range of the flexibility. The regrind allowance can be made larger than conventional tools. In addition, a step parallel to the tool axis is provided, and the tool's radial position accuracy of the tip is maintained even after the tip is moved by the guiding effect and the restraining effect due to the step, so the reproducibility of the cutting edge by re-polishing Is also secured, thereby increasing the number of times of re-polishing.

When the tip moves forward from the initial position by adjusting the position of the cutting blade after re-polishing, a gap is formed between the back surface of the tip and the inner end face of the slit. Receives the thrust in the tool axis direction applied to the shaft. Therefore, the presence of the adjust piece enhances the stability of the tip at the moving destination.

Further, when the number of the tightening members is two and the chip is pressed obliquely backward by the second tightening member, the back surface of the chip is also pressed against the support surface, and the fixing of the chip is further strengthened.

[0013]

FIG. 1 shows an embodiment of a rolling tool according to the present invention. This is an application of the present invention to a throw-away type ball end mill.

1 is a throw-away tip, 2 is a holder, 3 is a one-character slit provided across the center of the tip of the holder, 4 is a chip pocket provided on the outer periphery of the tip of the holder, and 5 is the depth of the slit. An adjustment piece insertion hole provided in the end face 3c, a first fastening member 6 as an essential element, a second fastening member 7 provided as required, and two opposed surfaces of the slit 3 are chip holding surfaces 3a, 3b. Used as

The throw-away tip 1 is a plate-like tip having a semicircular top end in a plan view.
a is provided symmetrically about the center of rotation. The chip 1 has a mounting hole 8 through which the fastening members 6 and 7 are inserted.
In the present invention, the hole is a long hole in the tool axis direction.

The chip 1 has a dimension t ₁ between chip holding surfaces.
(See FIG. 1 (b)) or t (see FIG. 8 (b)).

The tip holding surfaces 3a and 3b and the front surface 1b and the back surface 1c of the chip 1 sandwiched between these surfaces are flat surfaces parallel to the tool axis, and engage with each other on these surfaces (3a and 1b in the figure). Corresponding uneven steps 9 are provided. The step 9 is provided in parallel with the tool axis by vertically cutting the step forming surfaces (3a and 1b in the figure). Here, in order to facilitate the processing and stabilize the chip restraint, a step perpendicular to the step forming surface is provided, and further, in order to ensure that the chip holding surfaces 3a and 3b function, the concave side (the figure is used). The step (t ₁ −t ₀ ) on the chip side is slightly larger than the step on the convex side.

The first tightening member 6 is a screw for applying a tightening force in a direction perpendicular to the tool axis to a split portion formed by a slit at the tip of the holder 2. The halves are pulled toward each other with these screws, and the chip 1 is sandwiched between the sandwiching surfaces 3a and 3b.

The second fastening member 7 is also a screw. The second fastening member 7 fixes the chip 1 prior to the first fastening member 6, and makes the head of the screw abut and engage with the inlet chamfer 8 a of the mounting hole 8. The tip is screwed obliquely backward into one of the split parts. When this screw is tightened, the chip 1 is directly tightened, and the holding surface 3a and the slit end surface 3c
Is pressed against the two surfaces. Therefore, the tip 1 is more firmly fixed, and cutting stability is further improved.

The operating portions of the first and second tightening members 6 and 7 can be arranged on the same side unless there is a limit in space. Since the first tightening member 6 can be operated with a smaller force as it is closer to the tip end of the holder 2, it is preferable to arrange the first tightening member 6 in front of the holder 2 than the second tightening member 7.

The positioning and constraint of the throw-away insert 1 in the tool radial direction are performed by a step 9. On the other hand, positioning in the tool axis direction is first performed by bringing the back surface of the chip 1 into contact with the surface 3c. At this time, one end of the mounting hole 8 and the second
The chip 1 can be moved to the front of the holder 2 within the range of the flexibility generated between the chip 1 and the fastening member 7. By this movement, the amount of tip protrusion from the slit 3 is increased, and an extra re-polishing allowance is secured. Therefore, the re-polishing allowance becomes larger than before by the amount corresponding to the possible movement amount of the chip 1, and the possible number of re-polishing increases.

FIG. 2 shows a state in which the chip 1 has been advanced halfway by re-polishing. In this state, chip 1
Is separated from the surface 3c, the tool shown in the figure is additionally provided with an adjusting piece 10 for inserting and holding the shaft formed in the rear part into the hole 5, and the adjusting piece 10 is used to connect the back surface of the chip 1 and the surface 3c. The gap created between them is filled. In this case, the axial thrust applied to the tip 1 can be received via the adjustment piece 10. It is preferable to prepare several types of the adjusting pieces 10 having different thicknesses in the tool axis direction and sequentially replace the adjusting pieces 10 with thicker ones.

FIG. 4 shows a radius end mill of the second embodiment, FIG. 5 shows a chamfered end mill of the third embodiment (which can also be used as a reamer), and FIG. 6 shows a square end mill of the fourth embodiment. These end mills are different from the end mill of FIG. 1 only in the shape of the cutting edge 1a and the shape of the cutting edge 1a of the tip 1 and the holder 2 only. Therefore, common elements are denoted by the same reference numerals as in FIG. 1 and will not be described again.

FIG. 7 shows a drill according to a fifth embodiment. In this drill, the effective length of the holder 2 is longer than the depth of the perforation hole, and a twist groove (a straight groove) 11 for chip discharge is provided on the outer periphery of the holder. The throw-away tip 1 is a tip having a tip angle, and the tip is provided with a cutting blade 1a including a chisel blade. The rest of the configuration, particularly the configuration of the part characterizing the present invention, is almost the same as the ball end mill of FIG. Therefore, also in this case, the same elements as those in FIG.

In each of the embodiments described above, the single-sided engagement type in which one side of the throw-away insert is engaged with one of the chip holding surfaces, the rolling tool of the present invention may be a double-sided engagement type. it can. 8 to 14 show an embodiment of a double-sided engagement type milling tool.

FIG. 8 is shown in FIG. 1, FIG. 9 is shown in FIG. 2, FIG. 10 is shown in FIG. 3, FIG. 11 is shown in FIG.
In FIG. 14, the same reference numerals are given to the same elements in correspondence with FIG. Therefore, only the differences between FIGS. 8 to 14 and FIGS. 1 to 7 will be described. The milling tool shown in FIG. 8 and subsequent figures has uneven steps corresponding to the front surface 1b of the chip 1 where the surface is in contact with the chip holding surface 3a of the holder 2 and the rear surface 1c of the chip 1 where the surface is in contact with the chip holding surface 3b. 9 is provided so that both surfaces of the chip 1 are engaged with the holder 2. This double-sided engagement type milling tool is
Can have the same shape on the front and back surfaces. Also, as shown in FIG.
It is also possible to perform radial positioning of the chip at a location.

[0027]

As described above, according to the rolling tool of the present invention, the indexable insert sandwiched between the two halves of the holder tip can be moved in the tool axis direction while maintaining the positional accuracy in the tool radial direction. As a result, the re-polishing allowance can be increased by an amount corresponding to the amount of chip movement, and the number of times the cutting blade is regenerated by re-polishing increases, thereby increasing the economic effect.

The one provided with the adjustment piece is
Since the back surface of the chip is supported by the piece, re-polishing is easy and cutting stability is maintained.

Further, the one to which the second tightening member is added,
Since the back surface of the chip is also pressed against the support surface, the fixing of the chip is further strengthened, and the stability of cutting is further increased.

[Brief description of the drawings]

FIG. 1A is a plan view of a main part of a first embodiment (single-sided engagement type ball end mill). FIG. 1B is a front view of the same end mill. FIG. Fig. (D) Cross-sectional view taken along line II-II in (a).

2 (a) is a plan view of the end mill of FIG. 1 when a reground tip is used; FIG. 2 (b) is a cross-sectional view taken along line III-III in FIG.

3 (a) is a plan view showing the tip of the end mill of FIG. 1; (b) is a front view of the same tip; (c) is a side view of the same tip; (d) is a cross section taken along the line IV-IV in FIG. Figure

FIG. 4 (a) is a plan view of a main part of a second embodiment (single-sided engagement type radius end mill). FIG. 4 (b) is a front view of the same end mill.

5A is a plan view of a main part of a third embodiment (single-sided engagement type chamfering end mill). FIG. 5B is a front view of the same end mill. FIG.

6A is a plan view of a main part of a fourth embodiment (single-sided engagement type square end mill). FIG. 6B is a front view of the same end mill. FIG.

FIG. 7A is a plan view of a main part of the fifth embodiment (single-sided engagement type drill). FIG. 7B is a front view of the same drill. FIG.

8 (a) is a plan view of a main part of a sixth embodiment (double-sided engagement type ball end mill). FIG. 8 (b) is a front view of the same end mill. FIG. 8 (c) is a cross section taken along line II in FIG. Fig. (D) Cross-sectional view taken along line II-II in (a).

9 (a) is a plan view of the end mill of FIG. 8 when a re-ground tip is used, and FIG. 9 (b) is a cross-sectional view taken along line III-III in FIG.

10A is a plan view showing the tip of the end mill shown in FIG. 8; FIG. 10B is a front view of the same tip; FIG. 10C is a side view of the same tip; Figure

11A is a plan view of a main part of a seventh embodiment (a double-sided engagement radius end mill). FIG. 11B is a front view of the same end mill.

12 (a) is a plan view of a main part of an eighth embodiment (both-end engaging type chamfering end mill). (B) Front view of the same end mill. (C) Side view.

FIG. 13 (a) is a plan view of a main part of a ninth embodiment (double-sided engagement type square end mill). (B) Front view of the same end mill.

14A is a plan view of a main part of a tenth embodiment (a double-sided engagement type drill). FIG. 14B is a front view of the same drill. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 throw-away tip 1a cutting blade 1b front surface 1c back surface 2 holder 3 slit 3a, 3b chip holding surface 3c back end surface 4 chip pocket 5 adjustment piece insertion hole 6 first tightening member 7 second tightening member 8 mounting hole 8a entrance surface Taking part 9 Step 10 Adjustment piece 11 Twist groove

Claims (3)

[Claims] 1. A one-character slit is provided at the tip of a holder, a plate-like throw-away tip is inserted into the slit, and a halved portion of the holder tip by the slit is inserted in a direction in which the slit is sandwiched by a fastening member. In a throw-away type milling tool that clamps and holds the throw-away insert at the split portion, the insert holding surface of the split portion and one or both surfaces of the throw-away insert sandwiched between the surfaces may be provided. A throw-away type characterized by providing an uneven step parallel to a tool axis for vertically cutting the surface, and further providing a mounting hole for the throw-away tip through which the tightening member is inserted into an elongated hole in the tool axis direction. Milling tools. 2. The indexable milling tool according to claim 1, wherein an adjusting piece is interposed between a rear end surface of the slit and a back surface of the indexable insert. 3. A first tightening member for pulling the tightening member to the halved portion, and a second tightening member for directly tightening the indexable tip to one of the halved portions. The second fastening member is brought into contact with and engaged with the entrance chamfer of the mounting hole, and the fastening of the second fastening member is performed obliquely rearward. Item 3. A throw-away milling tool according to item 1 or 2.