JP2007168061A - Bite holder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bite holder with high machining accuracy and high machining speed having long life of a cutting chip. <P>SOLUTION: The bite holder 3 comprises a body part 3 made of tool steel; and a supersonic vibration part 2 made of titanium alloy. The body part 3 made of tool steel and the supersonic vibration part 2 made of titanium ally are joined by a method of a screw, an epoxy resin and welding. Then, the cutting chip 6 is mounted to the supersonic vibration part 2 by the screw 12. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a tool holder for attaching a cutting tip used in a lathe.

  2. Description of the Related Art Conventionally, when cutting an inner peripheral surface of a work made of, for example, a metal material or a plastic material, as shown in FIG. 1, a holding device 4 that is a tool post of a lathe 5 is provided with a cutting tip 6 for inner peripheral processing. The tool holder 1 is attached and the work 11 is attached to the chuck device 9 at the tip of the lathe spindle, and the work 11 is rotated and simultaneously fed to the holding device 4 which is a tool post. It was processed into dimensions.

  However, in the conventional cutting of the inner peripheral surface of the workpiece 11, chatter vibration is generated between the tool holder 1 and the workpiece 11 during the cutting, and this chatter vibration deteriorates the machining accuracy and shortens the tool life. There was a problem inviting.

  In particular, in such a cutting process, it is necessary to make the protrusion length of the tool holder 1 longer than the processing depth of the work 11. For this reason, the protrusion length of the tool holder 1 increases as the processing depth of the work 11 increases. If the tool holder 1 becomes longer and the tool holder 1 becomes longer, the chatter vibration is more likely to occur.

  Furthermore, when the work 11 has a small inner diameter, it is necessary to reduce the diameter of the tool holder 1 accordingly. However, when the tool holder 1 is thinned, the rigidity of the tool holder 1 is reduced, and chatter vibrations are more likely to occur. It tends to occur.

  In order to solve such a problem in the conventional cutting process, the ultrasonic vibration shown in Patent Document 1 in FIG. 2 is applied to the cutting tool, and chatter vibration generated between the tool holder and the workpiece during the cutting process. There are some products that aim to increase the tool life with good machining accuracy and good machining efficiency.

  The processing method for applying the ultrasonic vibration is called ultrasonic cutting, and is described in detail in Non-Patent Document 1, for example. Ultrasonic cutting has the advantages that the frictional resistance between the workpiece and the tool is reduced, so that the thermal distortion of the machined surface is reduced, the machining accuracy is increased, and the life of the cutting tool is extended. is doing.

  Here, the ultrasonic processing apparatus shown in Patent Document 1 in FIG. 2 will be described in detail. The cutting tool includes an ultrasonic torsional vibrator that generates ultrasonic torsional vibration, and a flexural vibration body that converts the torsional vibration generated by the ultrasonic torsional vibrator into bending vibration. The ultrasonic torsional vibrator includes a bolted Langevin type electrostrictive vibrator and is driven by a high frequency drive signal from the ultrasonic oscillator 10.

  The tip of the ultrasonic torsional vibrator is screwed with a magnifying horn that expands the amplitude of the torsional vibration generated from the ultrasonic torsional vibrator and transmits it to the flexural vibrator. The vibration amplitude is expanded several times by passing through the horn.

  Further, a bending vibration body for converting torsional vibration into bending vibration is screwed to the front end of the amplitude expanding horn with a screw (not shown), and a cutting tip 6 is screwed to the front end of the bending vibration body. Yes.

  The ultrasonic torsional vibrator, the magnifying horn, the flexural vibrator, and the cutting tip 6 have a vibration system in which a standing wave is generated and resonates at substantially the same frequency as the natural frequency of the ultrasonic torsional vibrator. It has become.

  Further, the torsional vibration system is attached to the case by a flange provided at a node of a standing wave generated in the amplitude expanding horn. A fan for cooling the ultrasonic torsional vibrator is provided behind the ultrasonic torsional vibrator.

  Further, when such a cutting tool is attached to a tool post of a lathe and a workpiece is subjected to circumferential cutting, it is preferable to use a vibration-proof alloy tool holder as means for attaching the cutting tool. .

  According to the cutting tool having such a configuration, the vibration generated in the holder during processing is reduced to 1/10 to 1/30 of the conventional, and high-precision and high-efficiency cutting can be performed. It is said that the service life has been improved.

Ultrasonic Handbook Editorial Committee, “Ultrasonic Handbook”, Maruzen Co., Ltd., August 1999, p679-684 Japanese Patent Laid-Open No. 7-164217

  However, there is a risk that the tool post, which is a holding device for holding the tool, and the bite holder, which is a part of the cutting tool, are rubbed with each other by ultrasonic vibration and seizure occurs.

  Also, the ultrasonic vibration reduces the frictional force between the tool holder and the tool post, which is the holding device, and the position of the tool holder in the holding device when a mechanical load is applied to the tool holder that is part of the cutting tool during processing. There is also a problem in that the machining accuracy deteriorates due to the change of.

  Further, the ultrasonic vibration of the ultrasonic vibrator propagates to a tool post that is a holding device, and the ultrasonic vibration applied to the cutting tip is reduced. In order to apply an ultrasonic vibration of a desired magnitude to the cutting tip, an unnecessary large ultrasonic AC power is applied to the ultrasonic transducer in order to apply vibration to an unnecessary part such as a tool post as a holding device. For this reason, the ultrasonic vibrator generates extra heat corresponding to the amount of ultrasonic vibration applied to unnecessary portions, and the temperature of the cutting tip, the holding device, etc. rises. This adversely affects machining accuracy, machining efficiency, and cutting chip life.

  As another problem, since the ultrasonic vibrator is bonded to the rear part of the tool holder, the ultrasonic vibration mode that can be excited by the cutting tip is limited. That is, there is a possibility that a desired vibration mode cannot be excited.

  An object of the present invention is to provide a long-life cutting tip and high-accuracy and high-efficiency ultrasonic machining using the cutting tip.

  The present invention relates to a tool holder used in a lathe, wherein an ultrasonic vibration section is provided at the tip of the tool holder.

  A piezoelectric element is joined to the ultrasonic vibration part of the tool holder.

  It has a hole or a screw part for attaching a cutting tip to the ultrasonic vibration part of the tool holder.

  Ultrasonic machining using the tool holder of the present invention enables high-precision and high-speed machining, and further increases the life of the cutting tip.

  A basic configuration according to the first embodiment is shown in a plan view of FIG. 3 and a side view of FIG. The tool holder 1 includes a main body 3 made of tool steel and an ultrasonic vibration part 2 made of titanium alloy. The main body 3 made of tool steel and the ultrasonic vibration portion 2 made of titanium alloy can be joined by a method such as screw, epoxy resin, or welding. Then, the cutting tip 6 is attached to the ultrasonic vibration unit 2 with the screw 12.

The main body 3 is also a portion held by the holding device 4. The ultrasonic vibration unit 2 is a vibration portion that vibrates ultrasonically. Since the material of the ultrasonic vibration part 2 is different from the material of the main body part 3, the ultrasonic vibration of the ultrasonic vibration part 2 is difficult to propagate to the main body part 3. When the acoustic impedance, which is the product of density and sound velocity, is different, the ultrasonic vibration is reflected at the interface of the material. The density of the titanium alloy is about 4420 kg / m ³ , the speed of sound is about 4900 m / s, and the acoustic impedance is about 2.2 × 10 ⁷ kg / m ² · s. On the other hand, the density of the tool steel is about 7900 kg / m ³ , the speed of sound is about 5200 m / s, and the acoustic impedance is 4.1 × 10 ⁷ kg / m ² · s. Thus, by utilizing the difference in acoustic impedance between the tool steel and the titanium alloy, only the ultrasonic vibration portion can be mainly vibrated.

  A piezoelectric ceramic as the piezoelectric element 7 is bonded to the ultrasonic vibration portion 2 as an ultrasonic vibration source by an epoxy resin. On both sides of the piezoelectric ceramic, there are electrode portions 13 provided by printing a silver paste, and are polarized in the plate thickness direction. An insulating paint is applied to the surface of the electrode portion 13 to ensure electrical insulation.

  Then, lead wires 8 are soldered to the piezoelectric ceramic, and these lead wires 8 are connected to the ultrasonic oscillator 10.

  Next, a method of operating a lathe using the tool holder 1 will be described with reference to FIG. A high frequency voltage is applied from the ultrasonic oscillator 10 to the plate-like piezoelectric ceramic. By applying a high-frequency voltage having a desired frequency, stretching vibration is excited in the length direction of the ultrasonic vibration unit 2 as indicated by an arrow in FIG. At substantially the same time, a motor (not shown) is started to rotate the chuck device 9 and the workpiece 11 mechanically fixed thereby. And the feed motor which is not illustrated is started, the cutting tip 6 is moved to the workpiece | work 11 direction, and the inner peripheral part of the workpiece | work 11 is cut. A cutting fluid is supplied to the cutting part at the time of cutting.

  The mass of the main body 3 of the tool holder 1 used here is several times larger than that of the ultrasonic vibration unit 2. Therefore, almost only the ultrasonic vibration part 2 vibrates. And the cutting tip 6 joined to the ultrasonic vibration part 2 vibrates.

  Since the total mass of the ultrasonic vibration part 2, the piezoelectric element 7 and the cutting tip 6 is less than a fraction of the mass of the main body part, the vibration necessary for vibrating the entire tool holder 1 is required. The energy is less than a fraction. Therefore, not only can the ultrasonic oscillator 10 be downsized, but also the temperature rise of the cutting tip can be reduced because the amount of power input is small, so that the machining accuracy and the machining speed can be increased.

  A basic configuration according to the second embodiment is shown in a plan view of FIG. The main body 3, the ultrasonic vibration part 2, and the cutting tip 6 of the tool holder 1 are the same as those used in the first embodiment. The configuration of the piezoelectric element 7 is different from that of the first embodiment, and the configuration is shown in the perspective view of FIG. The arrows in FIG. 7 indicate the polarization direction.

  When the voltages applied to the electrode portion 13a and the electrode portions 13b and 13c are different in phase by 90 degrees, vibration of an elliptical locus can be generated on the end face in the length direction.

  A lathe operating method using the tool holder 1 will be described with reference to FIG. A high frequency voltage is applied from the ultrasonic oscillator 10 to the electrode portion 13a, and the stretching vibration is excited in the longitudinal direction of the ultrasonic vibration portion 2 as indicated by an arrow a in the figure. A phase shifter 14 is connected to the ultrasonic oscillator 10, and a voltage having the same frequency as the voltage applied to the electrode portion 13a and a phase different by 90 degrees is applied to the electrode portion 13b and the electrode portion 13c. The polarization directions of the electrode part 13b and the electrode part 13c are opposite to each other as indicated by the arrows in FIG. 7. When voltages having the same phase are applied to the electrode part 13b and the electrode part 13c, the ultrasonic vibration part is changed to the arrow b. The bending vibration shown can be excited. Since the arrows a and b are orthogonal to each other and the vibration displacement phases are different by 90 degrees, the ultrasonic vibration part vibrates with an elliptical locus. And the cutting tip 6 joined to the ultrasonic vibration part 2 with the screw 12 vibrates with an elliptical locus.

  At the same time, a motor (not shown) is started almost simultaneously, and the chuck device 9 and the workpiece 11 mechanically fixed thereby are rotated. Then, a feed motor (not shown) is started, the tool holder 1 and the cutting tip 6 attached thereto are moved in the direction of the work 11, and the inner peripheral portion of the work 11 is cut. A cutting fluid is supplied to the cutting part at the time of cutting.

  When the vibration of the elliptical locus is excited on the cutting tip 6, the cutting tip 6 contacts the workpiece 11 and cuts only in a desired direction. In the reverse direction, the cutting tip 6 can be prevented from contacting the workpiece 11. The machining quality is improved by the vibration of the elliptical locus.

  The mass of the main body 3 of the tool holder 1 used here is several times larger than that of the ultrasonic vibration unit 2. Therefore, almost only the ultrasonic vibration part 2 vibrates. And the cutting tip 6 joined to the ultrasonic vibration part 2 vibrates.

  With such a configuration, since the vibration hardly propagates to the holding device 4 and there is almost no vibration loss, it is possible to excite the necessary magnitude of vibration with a small electric power. Therefore, since the rise in the temperature of the cutting tip can be reduced, the machining accuracy can be improved.

  Further, since vibration hardly propagates to the main body 3, there is little fear of damage to the main body 3 or the holding device 4 when the main body 3 and the holding device 4 come into contact with each other and vibrate.

  Further, since the ultrasonic vibration has an effect of reducing the friction coefficient, when the main body 3 or the holding device 4 vibrates, the holding force of the bite holder 1 of the holding device 4 decreases, and the load when the workpiece 11 is processed is reduced. Slips between the tool holder 1 and the holding device 4 to break the tool or damage the workpiece. As described above, since the vibration hardly propagates to the main body 3 or the holding device 4 in the cutting tool of the present invention, the holding force of the cutting tool of the holding device 4 is hardly lowered.

  Also, since vibration hardly propagates to the lathe, there is almost no risk of damage due to vibration.

  As described above, since only the cutting tip and the ultrasonic vibration portion can be vibrated, the cutting tip has a long life, high machining accuracy, and high machining efficiency can be provided.

  The tool holder 1 is composed of the main body 3 and the ultrasonic vibration part 2, but what is required is that the vibration of the ultrasonic vibration part 2 is not propagated to the main body 3 as much as possible.

  In the above example, the main body 3 and the ultrasonic vibration unit 2 are made of different materials so that the vibration of the ultrasonic vibration unit 2 is not propagated to the main body 3 as much as possible.

  As another configuration in which the vibration of the ultrasonic vibration unit 2 is not propagated to the main body unit 3, there are configurations shown in the perspective views of FIGS. 8 and 9.

  The perspective view shown in FIG. 8 is a perspective view showing a part of the tool holder 1, but the main body 3 and the ultrasonic vibration part 2 are made of the same tool steel. In order not to propagate the vibration of the ultrasonic vibration part 2 to the main body part 3, the propagation of vibration is reduced by providing the groove part 15 on the surface of the ultrasonic vibration part 2 that contacts the main body part 3. Here, the groove portion 15 is provided on the surface of the ultrasonic vibration portion 2, but the effect is the same even if the groove portion 15 is provided in the main body portion 3.

  The perspective view shown in FIG. 9 is a perspective view showing a part of the tool holder 1, but the main body 3 and the ultrasonic vibration part 2 are made of the same tool steel. In order not to propagate the vibration of the ultrasonic vibration part 2 to the main body part 3, the vibration damping steel plate 16 is joined to the surface of the ultrasonic vibration part 2 in contact with the main body part 3, whereby the ultrasonic vibration part 2 to the main body part 3. Propagation of vibration to can be reduced. Here, although the damping steel plate 16 is joined to the ultrasonic vibration part 2, the effect is naturally the same even if the damping steel plate 16 is joined to the main body part 3.

  The tool holder of the present invention can be used for a lathe.

It is a top view which shows the conventional lathe and cutting tool. It is a partial cross section top view which shows the conventional ultrasonic cutting tool. It is a top view which shows the tool holder of the 1st structure of this invention. FIG. 4 is a side view of the tool holder shown in FIG. 3. It is a top view which shows the lathe using the tool holder of the 1st structure of this invention. It is a top view which shows the bite holder of the 2nd structure of this invention. It is a perspective view which shows the piezoelectric ceramic used in FIG. It is a perspective view which shows the bite holder of another structure of this invention. It is a perspective view which shows the bite holder of another structure of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Byte holder 2 Ultrasonic vibration part 3 Main body part 4 Holding device 5 Lathe 6 Cutting tip 7 Piezoelectric element 8 Lead wire 9 Chuck apparatus 10 Ultrasonic oscillator 11 Work 12 Screw 13 Electrode part 14 Phase shifter 15 Groove part 16 Damping steel plate

Claims (3)

  A tool holder used in a lathe is characterized in that an ultrasonic vibration section is provided at the tip of the tool holder.   The tool holder according to claim 1, wherein a piezoelectric element is bonded to the ultrasonic vibration section.   The tool holder according to claim 1, further comprising a hole or a screw part for attaching a cutting tip to the ultrasonic vibration part.

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