JPH07299629A - Groove machining device using ultrasonic vibration cutting - Google Patents

Abstract

PURPOSE:To reduce resistance or generation of heat at cutting time, and lengthen the service life or prevent deformation by installing an ultrasonic torsional vibrator in one end part of,a rotary shaft, and installing a milling cutter for groove machining in a loop position of a standing wave generated at ultrasonic vibration time of the rotary shaft in the vicinity of the other end part of the rotary shaft. CONSTITUTION:An ultrasonic vibration cutting unit l inputs high frequency electric energy from an oscillator 8 to a bolt-fastened Langevin electrostrictive torsional vibrator 3 through a slip ring 2. At this time, the vibrator 3 is fastened to the rear end of a rotary shaft 4 by a screw, and the rotary shaft 4 also serves as an amplitude enlarging horn to enlarge and transmit an amplitude of torsional vibration. In the middle of the rotary shaft 4, a metal saw 7 is installed in a loop position of a standing wave generated when this causes torsional vibration. A resonance horn 5 is installed on the tip of the rotary shaft 4. The whole of a cutting unit l is rotatably supported with a machining device or the like by a bearing 9. On the other hand, rotation of the cutting unit l is transmitted by a rotary driving pulley 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic vibration cutting unit, an ultrasonic torsional vibration milling machine incorporating the same, and a method for manufacturing a "stator for an ultrasonic motor" using the milling machine.

[0002]

2. Description of the Related Art A grooving milling cutter is a grooving tool (cutting tool) for a milling machine, which is composed of a donut plate-shaped substrate and a large number of cutting edges attached to the outer periphery thereof, and cuts a workpiece while rotating. Means a cutting tool. The milling machine has a hole in the center, and the rotary shaft is attached to the rotary shaft by passing through the hole.

The milling machine is mainly composed of a rotating shaft (main shaft) having a milling cutter, a rotating means for rotating the rotating shaft,
It consists of a feed mechanism that moves or rotates the workpiece relative to the milling cutter. Generally, a milling machine is often used when cutting a groove on a workpiece (grooving). To cut the groove, a side milling cutter, an end mill, a metal saw, a saw and the like are used as a groove milling cutter. In particular, a metal saw is selected as the milling cutter when cutting a groove deep with respect to the width.

[0004] The cutting process including the grooving with a milling machine involves intermittent collision between the cutting edge and the work piece, so that the work piece cannot move smoothly "cutting resistance".
There is a problem that the blade tip or the workpiece is heated and the blade tip is worn (wear is evaluated by the service life) or damaged, or the workpiece is deformed or deteriorated. In particular, the work material is a hard-to-cut metal material (eg stainless steel, permalloy,
In the case of Invar, Titanium, etc.) these problems are serious. Incidentally, a hard-to-cut metal material is used as a material for a stator for an ultrasonic motor.

On the other hand, a technique of vibrating the cutting edge of the cutting tool with ultrasonic waves has been proposed (Japanese Patent Publication No. 52-31594). The proposed technology eliminates the time fluctuation of the work material in the cutting direction by vibrating the cutting edge at a frequency sufficiently higher than the natural frequency of the work material (4 times or more). It is possible to perform machining with high form accuracy without running out of the work material and without chattering.

[0006]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention In milling, intermittent cutting is performed due to its mechanism. Therefore, the tool used is often a high-speed steel (high-speed tool steel) that is resistant to impact force, and it is often impossible to use cemented carbide, which is commonly used in turning. Although high-speed steel has a high impact resistance, there is a problem that the tool life is extremely short when cutting a highly difficult-to-cut material.

Further, in the groove processing of the difficult-to-cut material, heat generation during the processing becomes extremely large. Therefore, there is a problem that a work-affected layer is liable to be generated on the work piece and the work piece is deformed after the work depending on the shape of the work piece. On the other hand, in the conventionally proposed machining technology for vibrating the cutting edge (Japanese Patent Publication No. 52-31594), it is easy to apply it to turning, shapers and shapers, but it is difficult to apply it to milling. there were. The object of the present invention is to solve this problem.

[0008]

Therefore, according to the present invention, firstly, an ultrasonic vibrator for generating ultrasonic torsional vibration, a rotary shaft having the vibrator attached to one end thereof, and the vibrator. An ultrasonic vibration cutting unit consisting of a milling cutter attached at a position of an antinode of a standing wave generated on the rotary shaft when the rotary shaft is ultrasonically vibrated at, and near to the other end (claim 1). I will provide a. It is preferable that the rotating shaft also serves as an amplitude expanding horn that expands the amplitude of ultrasonic vibration (claim 2). Further, it is preferable to add a resonance horn to the tip of the rotary shaft (claim 3).

The ultrasonic torsional vibration is 15 kHz to 100 kHz.
It is preferably kHz. Further, the present invention provides an ultrasonic vibration cutting unit according to any one of claims 1 to 4, a rotating means for rotating the rotary shaft of the unit, a driving means for driving the ultrasonic vibrator in the unit, and the milling cutter. There is provided an ultrasonic torsional vibration milling machine (claim 5) including a feed mechanism for relatively moving or rotating a workpiece.

INDUSTRIAL APPLICABILITY The milling machine of the present invention is useful for cutting hard-to-cut metal materials, especially for manufacturing "stator for ultrasonic motor" made of hard-to-cut metal materials. The stator is manufactured by preparing a disk-shaped work piece and radially cutting a large number of grooves on the surface thereof. To cut this groove,
A milling machine in which the milling machine is a metal saw or a sliver saw is used.

Therefore, the present invention also provides an ultrasonic torsional vibration milling machine (claim 6) according to claim 4 in which the milling machine is a metal saw or a saw, and further a disk-shaped workpiece is prepared, A method of manufacturing a stator for an ultrasonic motor by radially cutting a large number of grooves on a surface thereof, wherein the grooves are cut using the "ultrasonic torsional vibration milling machine of claim 6." Item 7) is provided.

[0012]

Operation: As ultrasonic vibration, vibration modes such as vertical vibration, flexural vibration, and torsional vibration are known. Ultrasonic transducers that generate ultrasonic torsional vibration are also available as commercial products. The ultrasonic oscillator mainly includes a piezoelectric element (piezo effect element), and when a high frequency voltage is applied to the piezoelectric element by the driving means, the main body causes ultrasonic torsional vibration.

This ultrasonic transducer is attached to the end of the "rotary shaft that also serves as the horn". When the oscillator is torsionally oscillated, the rotating shaft is ultrasonically oscillated in the forward and reverse directions. This ultrasonic torsional vibration propagates in the rotating shaft and the resonance horn,
It is reflected at the end of the resonance horn and returns to the oscillator. At this time, the vibration toward the end of the resonance horn and the vibration returning from the end interfere with each other to generate a standing wave in the entire unit. The vibration mode of this standing wave is shown in 6 of FIG. The standing wave has the maximum amplitude (antinode) at the open end (the end that is not fixed), and is one of the wavelengths of ultrasonic waves that propagate in the unit.
In the cycle of / 2, the part (node) where the amplitude is 0 and the part (antinode) where the amplitude is maximum appear alternately.

By attaching a milling cutter to the belly portion, it is possible to apply ultrasonic torsional vibration of maximum amplitude to the milling cutter. Also, the unit can be fixed to the milling machine main body by utilizing the section of the node where the amplitude is 0.
In the present invention, it is preferable to satisfy the inequality: 40fa> Dn (claim 8 or 9).

However, f: vibration frequency of the milling cutter (H
z) a: Vibration amplitude (mm) of milling edge D: Diameter of milling machine (mm) n: Number of revolutions of milling machine (rpm) The material forming the cutting edge of the milling machine is high-speed steel (high speed steel) material, cemented carbide And so on.

[0016]

【Example】

(Embodiment 1 ... Cutting unit) FIG. 1 is a schematic sectional view of an ultrasonic vibration cutting unit 1 of this embodiment. High-frequency electric energy (20 kHz) from the oscillator (driving means) 8
z) is input to a Langevin type electrostrictive torsional oscillator 3 by bolting via a slip ring (rotatable contact) 2. The vibrator 3 is screwed to the rear end of the rotary shaft 4. Here, the rotating shaft 4 also serves as an amplitude expanding horn that expands and transmits the amplitude of the torsional vibration. This allows
As the ultrasonic torsional vibrations pass through the horn, the vibration amplitude is magnified 2 to 10 times. A metal saw 7 is attached in the middle of the rotary shaft 4. This mounting position is important, and the metal saw 7 is mounted at the position of the antinode of the standing wave generated when the rotary shaft 4 is torsionally vibrated. Rotating shaft 4
A resonance horn 5 is attached to the tip of the. The torsional oscillator 3, the rotary shaft 4 also serving as the amplitude-increasing horn, the metal saw 7, and the resonance horn 5 are integrated to generate a standing wave at a frequency substantially the same as the natural frequency of the torsional oscillator 3. It is a vibrating system that resonates. The standing wave is shown in vibration mode 6.

The cutting unit 1 can be rotatably mounted on a processing device or the like by a bearing 9. Cutting unit 1
The rotation is transmitted by the rotation driving pulley 10 attached to the rear end. In the embodiment, the resonance frequency of the vibration system under no load is about 20 kHz, and the amplitude of the metal saw blade edge is about 25 μm when the oscillator output is 30 W. (Embodiment 2 ... Milling machine and grooving) FIG. 2 shows a main part of the milling machine of this embodiment to which the cutting unit 1 of the embodiment 1 is attached. 2 (a) shows the front, (b)
Shows the side surface of the unit part. The milling machine includes a base (not shown), an arm 16 fixed to the base, and a cutting unit 1 according to the first embodiment mounted below the arm 16 via a bearing 9.
And a drive motor 14 and a moving table 11 on which a workpiece is mounted and which is moved. As shown in FIG. 2B, the rotary shaft of the drive motor 14 and the rotary drive pulley 10 of the unit are connected by a belt 15.

Next, the function of the milling machine will be described. The work piece 12 is attached to the moving table 11 via the torch 13. The drive motor 14 rotates the rotary drive pulley 15 of the cutting unit of the first embodiment through the rotary drive belt 15. As a result, the metal saw 7 rotates. At the same time, turn on the drive of the cutting unit,
Ultrasonic vibration of metal saw. In this state, the moving table 11 is moved in the back force direction of the metal saw 7 to set the cut amount. Then, the table 11 is moved in the tangential direction of the metal saw 7. Thereby, the workpiece 12
A notch is made and a groove is gradually formed.

The metal saw 7 of this embodiment has a width of 1 mm,
The diameter is 75 mm. Rotation speed is 25 to 300 rpm
And The moving speed of the moving table is 20 to 30 per minute.
It was set to 0 mm. The grade of the work piece was Invar, which was a difficult-to-cut material, and the cut amount was 2 to 3 mm. The cutting resistance at the time of grooving according to this example was 2 kg in the main component force direction and 2 kg in the back component force direction (using a crystal type three component force measuring device).
Comparing this with the processing by an ordinary milling machine, it is reduced to about 1/10 in the main component force direction and about 1/4 in the back component force direction. For this reason, the tool life is significantly extended, and when machining with a metal saw using an ordinary milling machine, 400 mm-
In the present embodiment, although it was worn at a machining distance of 500 mm, machining was possible for 10 m or more, and the life of the cutting tool was improved 20 times or more as compared with rough machining.

Further, since the cutting resistance is reduced, heat generation during processing is reduced. Therefore, the hardening of the surface of the work piece after processing was reduced to about 1/5 in hardness (measured by a Vickers hardness meter). Further, the work-affected layer on the surface of the work piece is reduced, and the work piece after the work is less deformed. (Example 3 ... Manufacture of Stator) FIGS. 3 and 4 are views showing main parts of a groove machining device for a ring stator for an ultrasonic motor to which the cutting unit of Example 1 is attached. The front view is shown.

The groove machining device for the ring stator fixes a base (not shown), a main shaft of the base (not shown), the cutting unit 1 of the first embodiment fixed to the main shaft, and a workpiece (ring stator) 18. The table 13 (X table 19, Y table 23) on which the hiring 13, the hiring 13, the indexing board 21 for positioning in the rotation direction, the indexing board 21 and the movement controllable in the three-axis (X, Y, Z) directions. ) Consists of.

Next, the function of the groove machining device for the ring stator will be described. Set the switch of the driving means of the ultrasonic vibration cutting unit 1 to O
When set to N, the metal saw 7 is ultrasonically vibrated. At the same time, the cutting unit 1 is rotated in the rotation direction 17. Set the X-table 19 in the cutting direction 20 and the stator 18
Moves to a place where does not hit the metal saw 7.

The Y table is moved in the direction opposite to the feeding direction 24 until the metal saw 7 does not hit the inner circumference of the stator 18, and then the X table is moved in the cutting direction 2
Set to 0 Move to the depth of cut. The indexing board 21 is rotated in the indexing direction 22 by a predetermined angle. The Y table 23 is moved in the feed direction 24 at a constant speed until the center of the metal saw 7 passes through the outer circumference of the stator 18. This completes the processing of one groove.

The Y table 23 is returned in the direction opposite to the feed direction 24 until the metal saw 7 does not hit the inner circumference of the stator 18. Steps are repeated until the groove is completely processed 360 degrees around the circumference of the stator. Move the X table 19 in the direction opposite to the cutting direction,
The ultrasonic vibration and rotation of the cutting unit 1 are stopped, and the processing is completed.

The metal saw of this embodiment has a width of 1 mm, a diameter of 45 mm and is made of high speed steel (high speed steel). The rotation speed is 100 to 300 rotations per minute. The moving speed of the moving table was 50 to 200 mm per minute. The indexing rotation angle is 4 ° ~
It was set at 10 °. The material of the work piece (ring stator) is
It is a nickel-based metal. The cut amount is 2 to 3 mm.

The cutting resistance at the time of grooving according to this embodiment is 1 in the main component force direction as compared with the conventional method using a milling machine.
It was confirmed that it was / 10, and about 1/6 in the direction of the back force component (using a crystal type 3 component force measuring device). Since the cutting resistance is greatly reduced, heat generation during processing is suppressed, and there is no inconvenience that the stator is deformed after processing.

[0027]

According to the present invention, the cutting resistance during cutting is greatly reduced and the life of the cutting tool is remarkably extended. Further, the heat generated during cutting was reduced, and the deformation of the work piece after cutting was reduced. This effect is particularly remarkable in the groove processing of the ring stator for the ultrasonic motor. Further, since the vibration generated during cutting is significantly reduced, there is an effect that chipping does not occur at the cutting edge of the cutting tool even if cutting is performed using a cemented carbide metal saw. The life of the blade tool will be greatly extended by the use of a super hard metal saw.

[Brief description of drawings]

FIG. 1 is a sectional view of an ultrasonic vibration cutting unit for groove machining according to an embodiment of the present invention.

FIG. 2 is a schematic view showing a state in which an ultrasonic vibration cutting unit for groove machining is attached to an arm of a milling machine according to an embodiment of the present invention.

FIG. 3 is a side view of a main part of a groove machining device for a ring stator for an ultrasonic motor according to an embodiment of the present invention.

FIG. 4 is a front view of FIG.

[Explanation of symbols]

 1 ・ ・ ・ Ultrasonic vibration cutting unit 2 ・ ・ ・ ・ ・ ・ Slip ring 3 ・ ・ ・ ・ ・ ・ Torsion vibrator 4 ・ ・ ・ ・ ・ ・ ・ Rotating shaft 5 ・ ・ ・ ・ ・..Resonance horn 6 ... Vibration mode 7 ... Metal saw 8 ... Oscillator (driving means) 9 ... Bearing 10 ...・ ・ Rotary drive pulley 11 ・ ・ ・ ・ ・ ・ Movable table 12 ・ ・ ・ ・ ・ ・ ・ Workpiece 13 ・ ・ ・ ・ ・ ・ ・ Employment 14 ・ ・ ・ ・ ・ ・ ・ Drive motor 15 ・ ・ ・・ ・ ・ ・ Rotary drive belt 16 ・ ・ ・ ・ Arm 17 ・ ・ ・ ・ Tool rotation direction 18 ・ ・ ・ ・ ・ ・ Ring-shaped stator 19 ・ ・ ・ ・ X table 20 ・･ ･ ･ Workpiece cutting direction 21 ･ ･ ･ Indexing board 22 ･ ･ ･ Indexing rotation direction 23 ･ ･ ･ Y Cable 24 ... ・ Work feed direction

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H02N 2/00 C

Claims (9)

[Claims] 1. A rotating shaft having an ultrasonic vibrator for generating ultrasonic torsional vibration attached to one end thereof, and a stationary shaft generated on the rotating shaft when the rotating shaft is ultrasonically vibrated by the vibrator. Ultrasonic vibration cutting unit consisting of a groove milling cutter attached at the antinode of the wave and near the other end. 2. The ultrasonic vibration cutting unit according to claim 1, wherein the rotary shaft also functions as an amplitude expanding horn for expanding the amplitude of the ultrasonic vibration. 3. The ultrasonic vibration cutting unit according to claim 1, wherein a resonance horn is added to the tip of the rotary shaft. 4. The ultrasonic torsional vibration is from 15 kHz to
It is 100 kHz, The ultrasonic vibration cutting unit of Claims 1-3 characterized by the above-mentioned. 5. The ultrasonic vibration cutting unit according to claim 1, rotation means for rotating the rotary shaft of the unit, drive means for driving the ultrasonic vibrator in the unit, and the milling cutter. An ultrasonic torsional vibration milling machine consisting of a feed mechanism that moves or rotates the workpiece relative to the above. 6. The ultrasonic torsional vibration milling machine according to claim 5, wherein the milling cutter is a metal saw or a saw. 7. A method for manufacturing a stator for an ultrasonic motor by preparing a disk-shaped work piece and radially cutting a large number of grooves on the surface of the work piece, wherein the grooves are formed according to claim 6. "Ultrasonic torsion vibration milling machine". 8. The ultrasonic torsional vibration milling machine according to claim 5, which satisfies the following inequality: 40fa> Dn. Where f: ultrasonic torsional vibration frequency of milling cutter (Hz) a: vibration amplitude of cutting edge of milling cutter (mm) D: diameter of milling cutter (mm) n: rotational speed of milling cutter (rpm) 9. The method according to claim 7, wherein the following inequality: 40fa> Dn is satisfied. Where f: ultrasonic torsional vibration frequency of milling cutter (Hz) a: vibration amplitude of cutting edge of milling cutter (mm) D: diameter of milling cutter (mm) n: rotational speed of milling cutter (rpm)