JP2008012600A - Arbor for milling cutter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an arbor for a milling cutter capable of using the arbor improved in rigidity by relatively increasing an outer diameter of an arbor main body in relation to the diameter of a cutter by high-feed machining without troubles. <P>SOLUTION: In this arbor, a tool mounting shaft is provided at a center of a distal end of the arbor main body 3, the tool mounting shaft is inserted into a mounting hole at a center of a back face of the cutter 10, and the cutter 10 is fixed to the distal end of the arbor main body 3 by fastening the cutter 10 with a mounting bolt screwed into a screw hole at a center of the tool mounting shaft. In the arbor, a chip discharge groove 6 is provided on an outer periphery of the arbor main body 3. As a result, machining can be performed under a high-feed condition by mounting the cutter 10 having a small diameter difference with the arbor main body 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an arbor for a milling cutter suitable for use in combination with a cutter having a small diameter difference from the arbor body.

  An arbor for a milling cutter is composed of a tool shank mounted on a spindle (spindle) of a machine tool and an arbor body connected to the tip of the tool shank. At the tip of the arbor body, a tool mounting shaft to be inserted into the mounting hole in the center of the cutter is provided concentrically. Screw and tighten the mounting bolt to fix the milling cutter (mainly milling cutter) to the arbor body.

  This type of arbor is disclosed in, for example, Patent Documents 1 and 2 listed below. The purpose of the arbor disclosed in Patent Document 1 is to enable the coolant supplied through the passage inside the arbor body to be supplied to the cutting part without providing the coolant passage in the cutter itself. In order to do this, the portion excluding the tip side of the arbor body has a large diameter, and the coolant is jetted from the jet port provided at the tip of the large diameter.

  Moreover, the arbor which patent document 2 discloses makes the arbor main body into the taper axis | shaft with a small diameter at the front end side and a large diameter at the base side.

The arbor disclosed in Patent Document 1 has the large-diameter portion of the arbor body having the same diameter as or larger than the cutter. Therefore, the reason why the arbor body has a large diameter is not to improve rigidity. The arbor body exhibits high rigidity. The arbor disclosed in Patent Document 2 is not so large in the diameter difference between the arbor body and the cutter. In addition, the arbor body has a taper shaft with a large diameter at the base side, and therefore, this is also excellent in rigidity.
JP 2004-338000 A Japanese Patent Laid-Open No. 2004-237401

  In recent years, milling cutters tend to be used with a high cutting speed in order to meet the demand for high-efficiency machining. Since this arbor requires high rigidity in this high-speed cutting, an arbor whose outer diameter is relatively larger than the cutter diameter (an arbor whose diameter difference between the cutter and the arbor body is small) is used. Is done.

  The arbor disclosed in the above-mentioned Patent Documents 1 and 2 results in a relatively large outer diameter of the arbor body relative to the cutter diameter (the effective diameter of the cutting edge), and is excellent in rigidity. It is considered suitable for high speed cutting. However, including the arbor disclosed in Patent Documents 1 and 2, the arbor whose outer diameter is relatively larger than the cutter diameter is smaller than the axial dimension of the cutter formed on the workpiece. Increasing the cutter feed when machining a high standing wall (wall parallel to the cutter axis) or when machining the end face that intersects the wall along the wall (use under high feed conditions) ) May be limited.

If the workpiece wall height is larger than the cutter's axial dimension, the process proceeds with the arbor body facing the wall surface. At this time, the outer diameter of the arbor body is made relatively larger than the cutter diameter. When the arbor is used, the gap formed between the arbor body and the wall surface of the workpiece is reduced. The gap becomes smaller as the diameter difference between the cutter and the arbor body becomes smaller.
On the other hand, in the processing by the milling cutter, the thicker the chips, the greater the cutter feed. For this reason, 1) The diameter difference between the cutter and the arbor body is small. 2) If the two conditions that the cutter is fed at a high rate and thick chips are generated overlap, there is a concern that the generated chips may be caught between the arbor.

  In processing performed by combining a cutter with a small diameter difference and an arbor, the cutter feed is limited in order to eliminate the above-mentioned concerns. However, high feed of the cutter is indispensable for further improving the machining efficiency.

  An object of the present invention is to make it possible to use an arbor whose rigidity is increased by relatively increasing the outer diameter of the arbor body relative to the cutter diameter in high-feed machining without any trouble.

  In order to solve the above-described problems, in the present invention, a tool mounting shaft is provided at the center of the tip of the arbor body, the tool mounting shaft is inserted into a mounting hole at the center of the cutter, and a screw hole at the center of the tool mounting shaft is inserted. A chip discharge groove was provided on the outer periphery of the arbor body of the milling cutter arbor that fastens the cutter with a mounting bolt to be screwed and fixes the cutter to the tip of the arbor body.

  The arbor body preferably has a cylindrical shape (not a taper shaft). Further, the chip discharge groove provided on the outer periphery of the arbor body is preferably a twisted groove. It is preferable to provide a plurality of chip discharge grooves at intervals in the circumferential direction. Furthermore, a shallow groove whose depth is less than 20% in comparison with the outer diameter of the arbor body reduces the rigidity of the arbor body. It is preferable to be kept small.

  The arbor of the present invention is provided with a chip discharge groove on the outer periphery of the arbor body, and the generated chip is discharged through the chip discharge groove. Therefore, even if the cutter is increased when the gap formed between the arbor body and the wall surface of the workpiece is small, the chips are not caught. Therefore, it is possible to perform processing by using an arbor whose rigidity is increased by relatively increasing the outer diameter of the arbor body relative to the cutter diameter, and the cutter attached to the arbor is fed at high speed.

If a arbor body with a tapered shaft as shown in Patent Document 2 is used when machining a vertical wall surface of a workpiece, the maximum diameter portion of the arbor body is made smaller than the cutter diameter in order to avoid interference with the workpiece. As a result, it is difficult to ensure high rigidity of the arbor. On the other hand, the arbor body having a cylindrical shape can greatly increase the rigidity by relatively increasing the outer diameter in a region extending over the entire length with respect to the cutter diameter. Therefore, the arbor body preferably has a cylindrical shape.

Moreover, the twisted chip discharge groove gives a driving force to the chips discharged by the rotation of the arbor,
Increases chip discharge.

  This chip discharge groove has a depth that is not very large, in other words, if multiple pieces that can reduce the thinning of the arbor main body are small, the rigidity reduction of the arbor main body can be suppressed to ensure chip discharge without deficiency. Can do.

  Embodiments of the arbor of the present invention will be described below with reference to FIGS. The exemplified milling cutter arbor 1 is configured by integrally providing an arbor body 3 at the tip of a tool shank 2.

  The arbor body 3 has a tool mounting shaft 4 concentric with the body at the center of the tip. Further, a plurality of torque transmitting keys 5 (which are embedded in a groove on the front surface of the arbor main body 3) that protrude forward from the front surface of the arbor main body 3 are disposed around the tool mounting shaft 4 (the arbor shown is 2). Have).

  Furthermore, it has a twisted chip discharge groove 6 having a constant twist angle on its outer periphery. A plurality of the chip discharge grooves 6 are provided at a constant pitch in the circumferential direction in a region extending over the entire length of the arbor body 3. As shown in FIG. 2, the chip discharge groove 6 provided in the illustrated arbor 1 has a flat groove bottom 6 a and is excellent in workability. Here, the chip discharge groove 6 is a groove formed by two surfaces (groove bottom 6a and side wall 6b) intersecting at right angles. The side wall 6b is provided at a position rotated by an angle θ = 30 ° from the position of the reference line BL indexed at an angle of 90 ° as a wall standing up in the radial direction, and one end of the side wall 6b is on the outer periphery of the arbor body 3 Flat groove bottoms 6a to be cut through intersect at right angles.

  In addition, the arbor 1 of the example has integrally provided an arbor body 3 with an outer diameter φD = 47 mm and a length L = 200 mm at the tip of a tool shank 2 of JIS standard BT50, and the groove depth d = shown in FIG. 7 mm (d / D≈15%).

  A screw hole 7 (see FIG. 2) for screwing a mounting bolt is provided at the center of the tool mounting shaft 4 so as to open at the tip of the tool mounting shaft 4.

The arbor 1 configured as described above is used in combination with a cutter 10 as shown in FIG. The cutter 10 in FIG. 4 is a milling cutter. Such a cutter 10 is fitted on the outer periphery of the tool mounting shaft 4, and the torque transmission key 5 at the tip of the arbor body is engaged with a key groove 12 provided corresponding to the back surface of the cutter body 11. A cutter (not shown) is fastened to fix the cutter 10 to the tip of the arbor body 3.

  A mounting hole (not shown) is provided in the center of the back surface of the cutter body 11, and the tool mounting shaft 4 at the tip of the arbor is fitted into the mounting hole to center the cutter.

  A plurality of chip seats 13 each having a chip pocket 14 are formed on the outer periphery of the cutter body 11 at intervals in the circumferential direction, and a known clamping means 15 (such as a clamp piece or a clamp screw) is formed on each chip seat. The cutting edge tip 16 is mounted using a clamp screw.

  In the illustrated cutter 10, the outer diameter φD1 of the cutter body 11 is equal to the outer diameter φD of the arbor body 3, and the difference between the cutter diameter (effective diameter, larger than φD1) and the arbor body 3 is about 1 in radius. It is about 5mm.

  Thus, when the diameter difference between the cutter 10 and the arbor main body 3 is small, when processing is performed in the state of FIG. 4, that is, the state where the arbor main body 3 enters the workpiece side to the position along the wall surface F where the workpiece W stands up. When machining the wall surface F, the gap G secured between the wall surface F and the arbor body 3 is reduced, so that when a conventional arbor is used, machining under conditions that produce thick chips, for example, shaft Machining could not be performed with a large feed in the direction. The problem of the arbor of the present invention is eliminated, and the machining efficiency can be further improved by performing high-feed machining.

  In addition, the numerical value shown about the outer diameter of an arbor main body, the diameter difference with a length cutter, the depth of a chip discharge groove | channel, etc. is only an example to the last, and is changed suitably.

Side view showing an example of the arbor of the present invention Front view of the arbor body of the arbor of FIG. Sectional view along line III-III in FIG. Side view of the arbor of Fig. 1 with a cutter attached

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Arbor for milling cutter 2 Tool shank 3 Arbor body 4 Tool mounting shaft 5 Key 6 Chip discharge groove 6a Groove bottom 6b Side wall 7 Screw hole 10 Cutter 11 Cutter body 12 Key groove 13 Chip seat 14 Chip pocket 15 Clamp means 16 Cutting edge chip W Work

Claims (3)

A tool mounting shaft (4) is provided at the center of the tip of the arbor body (3), the tool mounting shaft (4) is inserted into a mounting hole at the center of the cutter (10), and a screw at the center of the tool mounting shaft (4) is inserted. In the arbor for milling cutter, the cutter (10) is tightened with a mounting bolt screwed into the hole (7), and the cutter (10) is fixed to the tip of the arbor body (3).
An arbor for a milling cutter, wherein a chip discharge groove (6) is provided on the outer periphery of the arbor body (3).   The arbor body for milling cutters according to claim 1, wherein the arbor body (3) is formed in a columnar shape, and a plurality of chip discharge grooves (6) twisted around the outer periphery of the columnar arbor body (3) are provided at intervals in the circumferential direction. .   The arbor for a milling cutter according to claim 1 or 2, wherein a depth d of the chip discharge groove (6) is 20% or less in a ratio to a diameter φD of the arbor body (3).

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