JP2007038310A - Cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting tool having a simple structure and effectively suppressing vibration during machining. <P>SOLUTION: An arbor 13 to be mounted on a main spindle 12 of a machine tool is installed with a cutter head having five cutting blades. A cutter head installation shaft part 21 of the arbor 13 for installing the cutter head is made of cast iron. The five cutting edges are disposed at irregular pitches and one cutting edge sequentially adjoining to a criterion cutting edge 36a in the opposite direction of a boring rotation direction has an axial step gradually retreating in the opposite direction to the boring advancing direction, and a radial step gradually expanding in the radial direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cutting tool fitted to a spindle of a machine tool.

  Among cutting tools used for machine tools such as machining centers, deep groove cutting tools have a large protruding length from the spindle position of the machine tool to the tool tip, so vibrations are likely to occur when machining a workpiece. For this reason, there are problems such as short tool life and difficulty in improving machining accuracy.

Therefore, a holding hole is drilled from the base end to the tip end of the tool body, a hollow member made of a super hard material is embedded in the holding hole, a gel-like damper substance is filled in the hollow portion of the hollow member, and There is a cutting tool in which vibration of a cutting blade attached to the tip of a tool body is suppressed by combining a hollow member having a damping effect and a damper substance (see, for example, Patent Document 1).
JP 2002-113603 A (Page 3, FIG. 2)

  This conventional anti-vibration cutting tool has a triple structure of a tool body, a hollow member of an ultra-hard material, and a gel-like damper substance, and there is a problem that the structure becomes complicated.

  This invention is made | formed in view of such a point, and it aims at providing the cutting tool which can suppress the vibration in process effectively, being simple in structure.

  The invention described in claim 1 comprises an arbor mounted on a spindle of a machine tool, and a cutter head attached to the arbor and provided with a plurality of cutting blades. The arbor is a cast iron cutter head to which the cutter head is attached. It is a cutting tool provided with the attaching shaft part.

  The invention according to claim 2 is such that the plurality of cutting blades in the cutting tool according to claim 1 is five.

  According to a third aspect of the present invention, a plurality of cutting blades in the cutting tool according to the first or second aspect are arranged at unequal pitch intervals.

  According to a fourth aspect of the present invention, the cutter head in the cutting tool according to any one of the first to third aspects is used for boring, and the plurality of cutting edges are in a boring rotation direction with respect to a reference cutting edge. The cutting edge adjacent in the opposite direction to the axial direction step where the cutting edge gradually retreats in the direction opposite to the boring direction, and the cutting edge adjacent to the reference cutting edge in the direction opposite to the boring rotation direction gradually expands in the radial direction. It is set as the arrangement | positioning structure provided with the radial direction level | step difference which diameters.

  The invention described in claim 5 uses a chip cutter for milling as the cutting blade in the cutting tool described in claim 4.

  According to the first aspect of the present invention, the cutter head mounting shaft portion of the arbor is made of cast iron, so that an excellent vibration damping factor can be obtained while the structure is simple, and the vibration during processing is made of a steel cutter. It can suppress more effectively than a head attachment shaft part.

  According to the invention described in claim 2, by using five cutting edges, vibration during processing can be more effectively suppressed than a four-blade cutter head.

  According to the third aspect of the present invention, the cutting blades arranged at unequal pitch intervals can reduce vibration during processing as compared to the cutter head of the cutting blades at equal pitch intervals.

  According to the fourth aspect of the present invention, as the cutter head rotates and moves in the axial direction in the boring advance direction, the cutter head gradually moves backward in the direction opposite to the boring advance direction through the axial step and through the radial step. The multiple cutting blades with tornado arrangement that gradually expand in the radial direction share the thrust cutting resistance in a balanced and stable manner with the radial step difference for each cutting blade. The vibration during processing can be reduced as compared with a cutter head having a plurality of cutting edges having no direction step.

  According to the fifth aspect of the present invention, the chip cutter for milling is suitable for dispersing the cutting resistance in the thrust direction, and is therefore suitable for the above-described tornado arrangement.

  Hereinafter, the present invention will be described in detail with reference to one embodiment shown in FIGS.

  As shown in FIG. 1, the cutting tool 11 includes an arbor 13 attached to a spindle 12 of a machine tool such as a machining center, and a cutter head 14 attached to the arbor 13 and having a cutting edge.

  The arbor 13 includes a pull stud portion 16 that is clamped by a clamping mechanism 15 of the machine tool, a taper shank portion 17 that is fitted into the tapered hole of the main shaft 12, and a tool change arm (not shown) of an automatic tool changer. A flange portion 19 having an engageable clip groove 18, a chuck holder portion 20, and a cutter head mounting shaft portion 21 that is held at one end side by the chuck holder portion 20 and attaches the cutter head 14 to the other end side. I have.

  The cutter head mounting shaft portion 21 of the arbor 13 is a cast iron casting, and is a cast product made of high-strength cast iron such as JIS-FCD450 and FCD500.

  The cutter head mounting shaft portion 21 is provided with a positioning convex portion 22 for positioning the cutter head 14 on the distal end side, and a pair of rotations for locking the rotation of the cutter head 14 on both right and left sides of the positioning convex portion 22. A locking bolt 23 is screwed. A screw hole 24 is provided at the center of the positioning convex portion 22.

  On the other hand, the cutter head 14 has a head mounting hole 32 in the axial direction in the center of a steel head body 31 and a positioning recess 33 that fits with the positioning protrusion 22. A rotation locking groove 34 that engages with the rotation locking bolt 23 is provided in the direction.

  Then, the positioning concave portion 33 of the cutter head 14 is fitted into the positioning convex portion 22 of the cutter head mounting shaft portion 21, and the rotation locking bolt 23 of the cutter head mounting shaft portion 21 and the rotation locking groove 34 of the cutter head 14 With the head engaged, the head mounting bolt 35 inserted from the head mounting hole 32 of the cutter head 14 is screwed into the screwing hole 24 of the cutter head mounting shaft section 21, so that the tip of the cutter head mounting shaft section 21 is engaged. The cutter head 14 can be coaxially positioned on the part and fastened integrally.

  As shown in FIGS. 2 and 3, five cutting blades 36 a, 36 b, 36 c, 36 d, 36 e are arranged and attached to the cutter head 14 at unequal pitch intervals. As these cutting blades 36a, 36b, 36c, 36d, and 36e, a chip cutter for milling may be used.

  The cutter head 14 is used for boring processing in which a prepared hole drilled in advance in a workpiece is expanded, and the plurality of cutting blades 36a, 36b, 36c, 36d, and 36e are used as a reference. The cutting edges 36b, 36c, 36d, 36e, which are sequentially adjacent to the cutting edge 36a in the direction opposite to the boring rotation direction, gradually move backward in the direction opposite to the boring direction as shown in FIG. The cutting blades 36b, 36c, 36d, and 36e sequentially adjacent to the cutting blade 36a in the direction opposite to the boring rotation direction are provided with a radial step 38 that gradually increases in diameter in the radial direction as shown in FIG. It is comprised by arrangement | positioning, ie, a tornado arrangement | positioning.

  That is, in the tornado arrangement of the cutting blades 36a, 36b, 36c, 36d, 36e, the larger the axial projection amount, the smaller the radial projection amount, and the smaller the axial projection amount, the radial projection amount. large.

  As shown in FIG. 2, the head mounting hole 32 is formed in the center of the head main body 31, and five cutting blade mounting body fitting grooves 41 are provided around the head mounting hole 32. A plurality of cutting blade mounting bodies 42 are respectively positioned at right-angled inner corners of the blade mounting body fitting grooves 41, and through radial adjustment plates 43 such as shims whose total thickness is sequentially changed, FIG. Each cutting blade attachment body 42 is fixed by a radial fixing screw 44 shown in FIG.

  As shown in FIGS. 3 and 4, a presser claw fixing portion 45 provided by cutting a side surface in the rotational direction is formed in the upper half portion of each cutting blade attachment body 42. V-shaped cutting edge fitting grooves 46 are respectively provided in the upper part, and triangular cutting edges 36a, 36b, 36c, 36d, 36e are fitted into these cutting edge fitting grooves 46, respectively. The cutting blades 36a, 36b, 36c, 36d, and 36e are pressed and fixed by cutting blade pressing claws 48 fastened to the pressing claw fixing portion 45 of the cutting blade mounting body 42 by a cutting blade fixing screw 47, respectively.

  The cutting blade mounting body 42 has a long hole (not shown) that fits with the radial fixing screw 44 so that the movement can be adjusted in the axial direction when the radial fixing screw 44 is loosened. As described above, an axial adjustment screw 49 is screwed onto the bottom surface of each cutting blade attachment body 42, and its head portion 49a is engaged with the bottom surface of the cutting blade attachment body fitting groove 41. A plurality of tool engaging holes 49b for turning the screw are formed on the peripheral side surface of the head 49a of the axial adjustment screw 49.

  Since the total thickness of the radial adjustment plate 43 such as shims varies depending on the angle, the plurality of cutting blades 36a, 36b, 36c, 36d, 36e are arranged at unequal pitch intervals. When making these unequal pitch intervals remarkable, a plurality of cutting blade attachment body fitting grooves 41 may be formed at unequal pitch intervals.

  Next, the operation of the above embodiment will be described.

  By adjusting the number and thickness of the radial adjustment plates 43 such as shims sandwiched between the head body 31 and the cutting blade mounting body 42, the radial position of each cutting blade mounting body 42 is adjusted to Between the cutting edges 36a, 36b, 36c, 36d, 36e, the cutting edges 36b, 36c, 36d, 36e adjacent to the reference cutting edge 36a in the direction opposite to the boring rotation direction are gradually expanded in diameter. Each radial step 38 to be set is set.

  While the radial fixing screw 44 is loosened, the head 49a of the axial adjustment screw 49 is rotated by a tool (not shown) engaged with the tool engagement hole 49b, so that the cutting blade attachment body 42 is rotated. The cutting blades 36b, 36c, which are sequentially adjacent to the reference cutting blade 36a in the direction opposite to the boring rotation direction, between the plurality of cutting blades 36a, 36b, 36c, 36d, 36e. 36d and 36e are respectively set with axial steps 37 in which the bores gradually retreat in the direction opposite to the boring direction. After adjusting and setting the axial step 37, the respective radial fixing screws 44 are tightened to fix the cutting blade attachment body 42.

  When the cutting blades 36a, 36b, 36c, 36d, 36e are worn or damaged, the cutting blade fixing screw 47 is loosened to remove the cutting blade presser claw 48 from the cutting blades 36a, 36b, 36c, 36d, 36e, Remove the cutting blades 36a, 36b, 36c, 36d, 36e from the cutting blade fitting groove 46 of the cutting blade mounting body 42 and replace them with new ones, and again, the cutting blade 36a through the cutting blade pressing claw 48 by the cutting blade fixing screw 47. , 36b, 36c, 36d, 36e are fixed.

  Then, while rotating the cutter head 14, it is inserted concentrically into the pilot hole drilled in the workpiece and moved axially in the boring direction, the cutting edge 36a having the smallest diameter as a reference first becomes a pilot. The blade is subjected to cutting so as to slightly increase the diameter of the pilot hole while receiving cutting force in the thrust direction, and then gradually retreats in the direction opposite to the boring direction through the axial step 37 and radially. Each subsequent cutting edge 36b, 36c, 36d, 36e of the tornado arrangement gradually expanding in the radial direction through the step 38 expands the pilot hole by the radial step 38 by receiving the cutting force in the thrust direction. In this way, cutting is performed sequentially.

  Next, the effect of the cutting tool 11 shown in FIGS. 1 to 4 will be described with reference to the graphs shown in FIGS. The cutter head mounting shaft portion 21 of the arbor 13 used for verification is a cast iron FCD450 casting, and the workpiece is finished from a prepared hole diameter of φ55.4 mm to a machining diameter of φ63 mm.

  FIG. 5 shows the relationship between the arbor material of the cutting tool and the vibration waveform during the cutting process. FIG. 5A shows the case where the cutter head mounting shaft portion 21 of the arbor 13 is made of steel, and FIG. This is a case where the cutter head mounting shaft portion 21 of the arbor 13 is made of steel and an ultra-hard material is embedded from the base end to the tip of the steel material, and (c) is the cutter head mounting shaft portion 21 of the arbor 13. (D) is a case where the cutter head mounting shaft portion 21 of the arbor 13 according to the present invention is a cast iron casting.

  When these are compared, the case of (d) made of cast iron is more vibrated than the case of (a) made of steel, the case of embedding an ultra-hard material (b), and the case of a vibration-proof bar (c). I understand that it is small.

  As a result, the cutter head mounting shaft portion 21 of the arbor 13 is made of cast iron, so that an excellent vibration damping rate can be obtained while the structure is simple. It can confirm that it can suppress effectively.

  FIG. 6 shows the relationship between the number of blades and the arbor material of a cutting tool and the amount of cutting per hour. A cutting tool in which a cutter head having two cutting edges is attached to a steel arbor, A cutting tool in which a cutter head having a cutting edge is attached to a steel arbor, and a cutting tool 11 in which a cutter head 14 having five cutting edges 36a, 36b, 36c, 36d, 36e is attached to a cast iron arbor 13; Compared with the cutting tool using the same steel arbor, the 5-blade cutter head has a higher cutting efficiency and better cutting efficiency than the 2-blade cutter head. Even with a five-blade cutter head, the cutting tool 11 using the cast iron arbor 13 has less vibration even when the cutting conditions are raised than the cutting tool using the steel arbor. It turns out that there will be more.

  FIG. 7 shows the relationship between the cutting blade mounting pattern of the cutting tool and the vibration waveform during cutting. FIG. 7A shows a case where four cutting blades are arranged at equal pitch intervals, and FIG. When the blades 36a, 36b, 36c, 36d, 36e are arranged at equal pitch intervals, (c) is a case where the five cutting blades 36a, 36b, 36c, 36d, 36e are arranged at unequal pitch intervals. As shown in (a) and (b), in the case of five cutting blades 36a, 36b, 36c, 36d, 36e, the vibration during processing is greater than in the case of four cutting blades. The vibration can be effectively suppressed by remarkably reducing, and as shown in (b) and (c), the five cutting edges 36a, 36b, 36c, 36d, 36e are arranged at equal pitch intervals. However, it can be seen that vibrations during processing can be suppressed by arranging them at unequal pitch intervals.

  FIG. 8 shows the relationship between the cutting tool mounting pattern of the cutting tool and the cutting resistance (spindle resistance), and more than five cutting blades 36a, 36b, 36c than when four cutting blades are arranged at equal pitch intervals. , 36d, and 36e are arranged at equal pitch intervals, and when they are arranged at unequal pitch intervals, it is understood that the main shaft resistance (current value) that is the cutting resistance in the rotational direction acting on the main shaft 12 can be reduced.

  FIG. 9 shows the relationship between the cutting tool mounting pattern of the cutting tool and the cutting resistance (feed load), which is less than when the five cutting blades 36a, 36b, 36c, 36d, 36e are arranged at equal pitch intervals. It can be seen that the feed load, which is the cutting resistance acting in the direction of the spindle axis, can be reduced when the pitches are arranged at equal pitch intervals.

  FIG. 10 shows the relationship between the presence or absence of the axial step 37 and the radial step 38 and the magnitude of vibration. FIG. 10 (a) shows that the five cutting blades 36a, 36b, 36c, 36d, and 36e are flat at the same diameter position. Is a vibration waveform when cutting with a stepless tool (hereinafter, this stepless tool is referred to as a “normal tool”) in which the axial step 37 and the radial step 38 are not provided. This is a vibration waveform when five cutting blades 36a, 36b, 36c, 36d, and 36e are cut with a tornado tool sequentially arranged through an axial step 37 of 0.5 mm and a radial step 38 of 0.9 mm. It can be seen that the tornado tool can significantly suppress vibration compared to the normal tool.

  That is, as the cutter head 14 rotates and moves axially in the boring direction, it gradually retracts in the direction opposite to the boring direction through the axial step 37 and gradually expands in the radial direction through the radial step 38. Since the five cutting blades 36a, 36b, 36c, 36d, 36e with a diameter tornado arrangement share the thrust resistance in the thrust direction in a balanced and stable manner with the radial step difference for each cutting blade, The vibration during machining can be reduced as compared with a normal tool without the axial step 37 and the radial step 38.

  Since the cutting cutter for milling is suitable for distributing the cutting force in the thrust direction, the cutting cutter for milling is suitable as the cutting blades 36a, 36b, 36c, 36d, 36e having the above-mentioned tornado arrangement. .

  FIG. 11 shows the relationship between the feed amount per rotation of the cutting tool 11 and the cutting resistance (spindle resistance). When the feed amount per revolution is the same, the tornado tool has more spindle resistance (current) than the normal tool. Value) can be reduced.

  FIG. 12 shows the relationship between the feed amount per revolution of the cutting tool 11 and the cutting resistance (feed load). When the feed amount per revolution is the same, the tornado tool reduces the feed load compared to the normal tool. I understand that I can do it.

  Thus, since the vibration of the cutting tool 11 during cutting can be effectively suppressed, it is possible to improve machining accuracy, reduce cutting resistance, improve cutting speed, and improve workability.

  INDUSTRIAL APPLICABILITY The present invention can be used for a cutting tool for boring a prepared hole opened in a workpiece to a predetermined diameter.

It is the front view which notched one part which shows one Embodiment of the cutting tool which concerns on this invention. It is a top view which shows the cutter head of a tool same as the above. It is a front view which shows the cutter head of a tool same as the above. It is a front view which shows the cutting blade attachment body of a tool same as the above. It is a graph which shows the relationship between the arbor material of a cutting tool, and the vibration waveform in cutting, (a) when it is steel, (b) when embedding super hard material, (c) is a vibration proof bar. In the case of (d), (d) shows the case made of cast iron according to the present invention. It is a graph which shows the relationship between the number of blades of a cutting tool, the arbor material, and the cutting amount per time. It is a graph which shows the relationship between the cutting-blade mounting pattern of a cutting tool, and the vibration waveform during cutting, (a) is when four cutting blades are arrange | positioned at equal pitch intervals, (b) is five cutting blades Are arranged at equal pitch intervals, (c) shows a case where five cutting blades are arranged at unequal pitch intervals. It is a graph which shows the relationship between the cutting-blade attachment pattern of a cutting tool, and cutting resistance (spindle resistance). It is a graph which shows the relationship between the cutting blade attachment pattern of a cutting tool, and cutting resistance (feed load). (A) shows the vibration waveform when cutting with a tool without an axial step and radial step, and (b) shows the vibration waveform when cutting with a tornado tool with an axial step and radial step. It is a graph which shows. It is a graph which shows the relationship between the feed amount per rotation of a cutting tool, and cutting resistance (spindle resistance). It is a graph which shows the relationship between the feed amount per rotation of a cutting tool, and cutting resistance (feed load).

Explanation of symbols

12 Spindle
13 Arbor
14 Cutter head
21 Cutter head mounting shaft
37 Axial step
38 radial step

Claims (5)

An arbor mounted on the spindle of the machine tool;
A cutter head attached to the arbor and having a plurality of cutting blades;
The arbor has a cutter head mounting shaft portion made of cast iron for mounting the cutter head. The cutting tool according to claim 1, wherein the plurality of cutting blades is five. The cutting tool according to claim 1 or 2, wherein the plurality of cutting blades are arranged at unequal pitch intervals. The cutter head is used for boring,
Multiple cutting edges
An axial step in which the cutting blades adjacent to the reference cutting blade in the direction opposite to the boring rotation direction sequentially retreat in the direction opposite to the boring traveling direction,
4. The arrangement according to claim 1, wherein a cutting edge adjacent to the reference cutting edge in a direction opposite to the boring rotation direction is provided with a radial step in which the diameter gradually increases in the radial direction. Or the cutting tool described. The cutting tool according to claim 4, wherein a cutting cutter is used for cutting.

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