JP2018187726A - Vibration cutting device and vibration apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a working technique which achieves highly efficient working and furthermore allows for application of various vibration loci to a tool blade edge.SOLUTION: An ultrasonic vibration apparatus 10 comprises an actuator to which a cutting tool 11 is fitted and which generates ultrasonic vibration. A drive unit 30 applies a voltage to the actuator, thereby reciprocally vibrating an edge of the cutting tool 11 in one direction. A control part 20 controls the voltage applied by the drive unit 30. The ultrasonic vibration apparatus 10 has at least a first resonant frequency, and a second resonant frequency higher than the first resonant frequency. The control part 20 controls the applied voltage by the drive unit 30 so that the ultrasonic vibration apparatus 10 is simultaneously resonated at the first resonant frequency and at the second resonant frequency.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a vibration cutting device and a vibration device.

  In recent years, it has been required to form fine uneven shapes that improve functionality in optical parts and sliding parts. Patent Document 1 discloses a cutting device provided with a vibration device that causes the cutting edge of a cutting tool to vibrate elliptically with respect to a work material. This cutting device is a highly efficient precision micromachining for ferrous materials and brittle materials. Can be applied.

JP 2008-212427 A

  One of the fine irregularities formed on the functional surface is a microtexture in which a hole shape, a groove shape, and the like are periodically formed. The microtexturing technology aims to form a periodic structure and control the mechanical properties on the functional surface, and applied research in various fields has become active. For example, it is known that by forming a micro-texture that acts as an oil pool on the sliding surface that uses lubricant, the friction coefficient and wear can be reduced, and high lubrication can be achieved with a small amount of low-viscosity lubricant. ing. This micro texture is required to have a gentle shape at the boundary with the sliding surface.

  When machining microtextures, a method of cutting the machined surface by periodically vibrating the cutting edge of the cutting tool relative to the work material while relatively moving the vibrator equipped with the cutting tool and the work material Can be considered. When the vibrator is vibrated at a low frequency, the vibration trajectory of the tool edge can be controlled as desired, so that a complex periodic shape can be machined on the machining surface. However, the processing speed is slow and not efficient.

  In order to increase the efficiency, it is only necessary to increase the vibration frequency up to the ultrasonic range and move the vibrator and the work material at a relatively high speed. In order to obtain it, it is necessary to use a mechanical resonance phenomenon. In this case, the vibrator vibrates in a sine wave, and thus the shape of the obtained machining surface is limited to a shape depending on the sine wave locus of the tool edge.

  The present disclosure has been made in view of such a situation, and one of the objectives thereof is a processing technique that can provide various vibration trajectories to the tool edge while realizing high efficiency of processing. It is to provide.

  In order to solve the above problems, a vibration cutting device according to an aspect of the present invention includes a vibration device including an actuator to which a cutting tool is attached and generates vibration, and the vibration device includes a first resonance frequency and a first resonance. It has a second resonance frequency higher than the frequency and resonates simultaneously at the first resonance frequency and the second resonance frequency.

  Another aspect of the present invention is a vibration device including an actuator that generates vibration. The vibration device has a first resonance frequency and a second resonance frequency higher than the first resonance frequency, and resonates simultaneously at the first resonance frequency and the second resonance frequency.

  It should be noted that any combination of the above-described components and a representation of the present disclosure converted between a method, an apparatus, a system, a recording medium, a computer program, and the like are also effective as an aspect of the present disclosure.

  According to the present disclosure, it is possible to provide a processing technique that can provide various vibration trajectories to the tool blade edge while realizing high efficiency of processing.

It is a figure which shows schematic structure of an ultrasonic vibration cutting device. It is a figure which shows the function structure of an ultrasonic vibration cutting device. It is a figure which shows the some resonance mode of the vertical direction of an ultrasonic vibration apparatus. (A) shows a vibration waveform of a plurality of resonance modes, (b) shows a composite waveform of a plurality of vibration waveforms, and (c) is a diagram schematically showing a processed surface of a work material. (A) shows the vibration waveform of several resonance modes, (b) is a figure which shows the synthetic | combination waveform of several vibration waveform. It is a figure which shows the modification of an actuator and a drive device.

  FIG. 1 shows a schematic configuration of an ultrasonic vibration cutting apparatus 1 of the embodiment. The ultrasonic vibration cutting apparatus 1 is a cutting apparatus capable of performing a turning type process by reciprocally vibrating a cutting edge of a cutting tool 11 with respect to a work material 6. The ultrasonic vibration cutting device 1 of the embodiment is a roll lathe that turns a cylindrical work material 6 to process a roll for rolling, but may be another type of cutting device. The work material 6 is typically a die steel, a copper material, an aluminum material, or the like whose surface is plated with nickel phosphorus, but may be other materials.

  The ultrasonic vibration cutting device 1 includes a headstock 2 and a tailstock 3 that rotatably support a work material 6, and a tool post 4 that supports a vibration device 12 on which a cutting tool 11 is mounted on a bed 5. Prepare for. The ultrasonic vibration cutting apparatus 1 also includes a feed mechanism that moves at least the tailstock 3 with respect to the headstock 2, a feed direction parallel to the axial direction of the workpiece 6, and a cutting direction perpendicular to the axial direction. A feed mechanism is provided that moves the cutting tool 11 in a direction in which the cutting tool 11 approaches the rotation axis of the work material 6. During the cutting process, the work material 6 is rotated by the main shaft provided on the main shaft base 2.

  The vibration device 12 includes an ultrasonic vibration device 10 to which a cutting tool 11 is attached and which applies a one-way reciprocating vibration to the cutting edge of the cutting tool 11. The ultrasonic vibration device 10 is an ultrasonic vibrator, and includes an actuator that generates ultrasonic vibration inside. The actuator may be a piezoelectric element. In the embodiment, the frequency of “ultrasonic vibration” generally means a frequency exceeding the human audible range, and may be, for example, a frequency of 16 kHz or more. The ultrasonic vibration cutting device 1 uses the ultrasonic frequency band to realize processing with excellent silence.

  The drive device 30 is a driver that applies a voltage to the piezoelectric element of the ultrasonic vibration device 10 to vibrate the ultrasonic vibration device 10 and vibrates the cutting edge of the cutting tool 11 in one direction. In the embodiment, the driving device 30 reciprocally vibrates the cutting edge of the cutting tool 11 in the cutting direction. The control unit 20 supplies an application voltage control command to the driving device 30 to control the applied voltage to the piezoelectric element by the driving device 30. Specifically, the control unit 20 controls the voltage applied by the driving device 30 so as to realize a vibration control function for controlling the amplitude and phase of resonance and an automatic tracking function for the resonance frequency. In the illustrated example, the control unit 20 is provided in the headstock 2, but may be provided in a space other than that. The control unit 20 may control the voltage applied by the driving device 30 in cooperation with an NC control device (not shown) that controls the operation of the spindle and various feed mechanisms. Further, the control unit 20 may be configured to include an NC control device, and may control the operation of the main shaft and various feed mechanisms and may control the voltage applied by the drive device 30.

  FIG. 2 shows a functional configuration of the ultrasonic vibration cutting device 1. The ultrasonic vibration device 10 may be a Langevin type vibrator in which piezoelectric elements 13a and 13b are clamped with bolts 14 and generates longitudinal vibration in the longitudinal direction thereof. The cutting tool 11 may be attached to the tip of the ultrasonic vibration device 10 by brazing material or the like, but may be attached to a recess provided at the tip of the ultrasonic vibration device 10. In the embodiment, the ultrasonic vibration device 10 is arranged so as to longitudinally vibrate in the vertical direction with respect to the cylindrical work material 6, but may be arranged so as to vibrate longitudinally in an oblique direction. In addition, although an Example demonstrates the ultrasonic vibration apparatus 10 using the longitudinal vibration by resonance of a rough wave, the ultrasonic vibration apparatus 10 generate | occur | produces a one-way reciprocating vibration using a flexural vibration or a torsional vibration. It may be.

  The driving device 30 includes an oscillator 31 and an amplifier 32. The oscillator 31 is electrically connected to the piezoelectric elements 13a and 13b of the ultrasonic vibration device 10 via the amplifier 32, and applies a voltage to the piezoelectric elements 13a and 13b. The control unit 20 controls the voltage applied by the driving device 30 to vibrate the piezoelectric elements 13a and 13b so that the ultrasonic vibration device 10 resonates at a resonance frequency in the longitudinal direction.

  When the ultrasonic vibration device 10 resonates, the cutting edge of the cutting tool 11 forms the surface of the workpiece 6 at least in a periodic shape of a sine wave in the depth direction or a periodic shape in which a part of the sine wave remains. Can cut. The ultrasonic vibration cutting device 1 of the embodiment makes it possible to cut into a shape other than a sine wave by utilizing the mechanical resonance phenomenon of the ultrasonic vibration device 10.

  The ultrasonic vibration device 10 on which the cutting tool 11 is mounted is formed to have at least a first resonance frequency and a second resonance frequency higher than the first resonance frequency. The ultrasonic vibration device 10 may have a third resonance frequency that is higher than the second resonance frequency. The control unit 20 controls the voltage applied by the driving device 30 so that the ultrasonic vibration device 10 resonates simultaneously at a desired phase at least at the first resonance frequency and the second resonance frequency.

  FIG. 3 shows a plurality of longitudinal resonance modes of the ultrasonic vibration device 10. In the example shown in FIG. 3, the vibration mode having the lowest resonance frequency among the vibration modes having two or more nodes is combined with the vibration mode having an integral multiple of the resonance frequency, and the ultrasonic vibration device is used in a plurality of vibration modes. Exciting 10 In the example shown in FIG. 3, the 6th order resonance mode is combined with the 2nd order basic resonance mode.

  It is preferable that the ultrasonic vibration device 10 is formed so that the positions of the nodes corresponding to the plurality of resonance modes match at two or more locations, and is supported by the casing of the vibration device 12 at the positions of the plurality of matched nodes. In the example shown in FIG. 3, the positions of the nodes by a plurality of resonance modes are coincident at two locations, and the ultrasonic vibration device 10 has a housing of the vibration device 12 by the mounting portions 15a and 15b provided at the coincident node positions. Supported by As a result, vibrations in a plurality of resonance modes are efficiently transmitted to the cutting tool 11. In the case of a round bar-shaped longitudinal vibration, the position of the node in the fundamental resonance mode and the position of the node in the odd-numbered resonance mode overlap, so the processed shape is formed by a combination of the fundamental resonance mode and the odd-numbered resonance mode. The ultrasonic vibration device 10 of the embodiment is particularly advantageous.

FIG. 4A shows a vibration waveform 40a in the basic resonance mode and a vibration waveform 40b in the sixth resonance mode. The vertical axis represents vibration displacement [μm] and the horizontal axis represents time [second (× 10 ⁻⁴ )]. In this example, the fundamental resonance mode frequency is 20 kHz, the amplitude is 10 μm, the initial phase when viewed as a sine wave is 0 degree, the sixth resonance mode frequency is 60 kHz, the amplitude is 3.33 μm, and the initial phase is 180 degrees. It is said.

  FIG. 4B shows a vibration waveform 41 obtained by synthesizing the vibration waveform 40a in the basic resonance mode and the vibration waveform 40b in the sixth-order resonance mode. The control unit 20 controls the voltage applied by the driving device 30 so that the ultrasonic vibration device 10 resonates simultaneously at 20 kHz and 60 kHz. By simultaneously exciting the ultrasonic vibration device 10 in a plurality of resonance modes, the cutting tool 11 attached to the ultrasonic vibration device 10 can take the vibration locus shown in FIG.

  FIG. 4C is a diagram for explaining a machining shape formed by the vibration waveform 41. Here, the positive displacement represents the direction in which the ultrasonic vibration device 10 contracts, and the negative displacement represents the direction in which the ultrasonic vibration device 10 extends.

  When the vibration neutral point of the cutting edge of the cutting tool 11 is set at the surface position of the work material 6 and the ultrasonic vibration device 10 is vibrated with respect to the rotating work material 6, the tool cutting edge is moved when displaced in the forward direction. The tool cutting edge cuts the workpiece 6 when it is separated from the workpiece 6 and displaced in the negative direction. As a result, while leaving a non-cutting portion, a periodic shape having a recessed portion as a hatched portion in FIG. 4C is formed on the surface of the work material.

  In the vibration waveform 41, since the vibration speed decreases at the neutral point of vibration (displacement 0), the recess has a very gentle shape at the boundary with the non-cut portion. Such a boundary shape is desired for the microtexture that plays the role of an oil pool on the sliding bearing surface. According to the sinusoidal vibration of the single resonance mode, such a shape cannot be formed because the vibration speed at the neutral point of the vibration is large. However, in the embodiment, the ultrasonic vibration device 10 is operated in a plurality of resonance modes. By exciting, it becomes possible to form a shape that satisfies the required specifications of the microtexture.

FIG. 5A shows a vibration waveform 42a in the fundamental resonance mode, a vibration waveform 42b in the sixth resonance mode, and a vibration waveform 42c in the tenth resonance mode. The vertical axis represents vibration displacement [μm] and the horizontal axis represents time [second (× 10 ⁻⁴ )]. In this example, the fundamental resonance mode frequency is 20 kHz, the amplitude is 10 μm, the initial phase when viewed as a sine wave is 0 degree, the sixth resonance mode frequency is 60 kHz, the amplitude is 0.7 μm, and the initial phase is 180 degrees. The frequency of the 10th-order resonance mode is 100 kHz, the amplitude is 0.1 μm, and the initial phase is 0 degree.

  FIG. 5B shows a vibration waveform 43 obtained by combining a vibration waveform 42a in the basic resonance mode, a vibration waveform 42b in the sixth-order resonance mode, and a vibration waveform 42c in the tenth-order resonance mode. The vibration waveform 43 has a waveform close to a triangular wave. Thus, by exciting the ultrasonic vibration device 10 in a plurality of resonance modes at the same time, the cutting tool 11 mounted on the ultrasonic vibration device 10 can take various vibration trajectories. For example, when the vibration waveform 40b shown in FIG. 4A is set to an opposite phase, a synthesized waveform close to a rectangular wave can be obtained.

  The present disclosure has been described based on the embodiments. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to the combination of each component and each processing process, and such modifications are within the scope of the present disclosure. .

  FIG. 6 shows a modification of the actuator and the driving device. In the embodiment, the drive device 30 applies a voltage to the pair of piezoelectric elements 13a and 13b so that the ultrasonic vibration device 10 resonates in a plurality of vibration modes. However, in the modification, the drive device 30 includes a plurality of pairs. A voltage is individually applied to each piezoelectric element.

  FIG. 6 shows the actuator and the drive device 30 when the ultrasonic vibration device 10 is resonated in two vibration modes. The oscillator 31a is electrically connected to the pair of piezoelectric elements 13a and 13b via the amplifier 32a and applies a voltage. The oscillator 31b is electrically connected to the pair of piezoelectric elements 13c and 13d via the amplifier 32b and applies a voltage. The control unit 20 controls the voltage output from the amplifier 32a to vibrate the piezoelectric elements 13a and 13b so that the ultrasonic vibration device 10 resonates at one resonance frequency (first resonance frequency). In addition, the control unit 20 controls the voltage output from the amplifier 32b to vibrate the piezoelectric elements 13c and 13d so that the ultrasonic vibration device 10 resonates at another resonance frequency (second resonance frequency). In the modified example, the combination of the actuator, the oscillator 31 and the amplifier 32 is provided for each vibration mode of the ultrasonic vibration device 10, so that there is an advantage of facilitating high-amplitude vibration control for each actuator.

  In the embodiment, the driving device 30 reciprocally vibrates the cutting edge of the cutting tool 11 in the cutting direction. However, in a modified example, the cutting edge of the cutting tool 11 may reciprocate in the feeding direction. You may make it reciprocate in the predetermined middle direction between directions.

  In the embodiment, the second resonance frequency is an integer multiple of the first resonance frequency with respect to the lowest first resonance frequency. However, the second resonance frequency is not an integer multiple of the first resonance frequency. Also good. For example, when a pattern for a sheet for uniformly dispersing light is processed into the work material 6 in a liquid crystal panel or the like, a certain degree of randomness is allowed, so that the second is not an integral multiple of the first resonance frequency. The ultrasonic vibration device 10 may be resonated at a resonance frequency.

  Note that the control unit 20 uses a frequency that is the greatest common divisor of the first resonance frequency and the second resonance frequency (if the second resonance frequency is an integer multiple of the first resonance frequency, the frequency that is the greatest common divisor is the first common divisor. The relationship between the driving device 30 of the ultrasonic vibration device 10 and the cutting motion may be set so that the cutting motion is repeated at a frequency of 1 / N of the resonance frequency (where N is an integer). In the turning process shown in FIG. 1, the rotation frequency of the spindle attached to the spindle stock 2 may be set to 1 / N of the frequency that is the greatest common divisor. In that case, the phase of the microtexture processed at each rotation becomes equal, and the same microtexture is repeatedly formed at the same rotational position. Further, the microtexture is repeatedly formed at a frequency that is the greatest common divisor, and the number of repetitions is N times while the work material 6 is rotated once. Further, in the case of planing or shape cutting that repeats a linear cutting motion instead of turning, control may be performed so that the phase of ultrasonic vibration becomes the same value at the moment of starting each cutting motion. Also in that case, the phase of the microtexture processed by each cutting motion becomes equal, and the same microtexture is repeatedly formed at the same cutting motion position.

  Conversely, the control unit 20 is connected to the drive device 30 of the ultrasonic vibration device 10 so that the cutting motion is not repeated at a frequency of 1 / N of the frequency that is the greatest common divisor of the first resonance frequency and the second resonance frequency. A relationship of cutting motion may be set. In that case, the phase of the microtexture formed by each rotation or cutting motion is out of phase, and the microtexture having the same phase can be prevented from being formed at the same rotational position or the same cutting motion position.

  In the embodiment, an example in which the ultrasonic vibration device 10 that resonates simultaneously at a plurality of resonance frequencies is used for the ultrasonic vibration cutting device 1 is shown. However, the ultrasonic vibration device 10 is used for applications other than the ultrasonic vibration cutting device 1. For example, the apparatus may be used for a welding apparatus, a cleaning apparatus, a suspension apparatus, a sensor apparatus, and the like.

  Moreover, in the Example, it demonstrated that the ultrasonic vibration apparatus 10 resonated suitably in the ultrasonic frequency band of 16 kHz or more. In a modification, the ultrasonic vibration device 10 may be a vibration device that resonates in a frequency band of 16 kHz or less. The piezoelectric elements 13a and 13b, which are actuators, generate vibrations of 16 kHz or less. Even in this case, it is preferable that the resonating vibration device resonates in a frequency band in consideration of silence.

  In the embodiment and the modification, it is shown that a plurality of resonance frequencies are set in a predetermined relationship, but the resonance frequency of the ultrasonic vibration device 10 that is actually used does not necessarily match the set value. This is due to manufacturing error of the ultrasonic vibration device 10, thermal deformation after the start of vibration, external load (for example, cutting force), and the like. For this reason, if priority is given to maintaining the relationships set for a plurality of resonance frequencies, it is necessary to vibrate the ultrasonic vibration device 10 at a frequency slightly deviated from at least one of the resonance frequencies. Thus, even at a frequency slightly deviated from the resonance frequency, the amplitude enlargement ratio is large due to the vicinity of the resonance frequency, and a high vibration speed can be obtained. Therefore, in this specification, “resonance frequency” including frequencies near the resonance frequency at which a high vibration speed is easily obtained is expressed as “resonance”.

  An overview of aspects of the present disclosure is as follows. A vibration cutting device according to an aspect of the present disclosure includes a vibration device including an actuator that is mounted with a cutting tool and generates vibration, and the vibration device has a first resonance frequency and a second resonance frequency higher than the first resonance frequency. And simultaneously resonate at the first resonance frequency and the second resonance frequency. According to this aspect, by exciting the vibration device in a plurality of resonance modes at the same time, it is possible to impart various vibration trajectories to the tool edge while realizing high machining efficiency.

  The vibration cutting device may further include a drive device that applies a voltage to the actuator to reciprocate and vibrate the cutting edge of the cutting tool in one direction, and a control unit that controls an applied voltage by the drive device. The control unit controls the voltage applied by the driving device so that the vibration device resonates simultaneously at the first resonance frequency and the second resonance frequency. This makes it possible to resonate the vibration device simultaneously in a plurality of resonance modes.

  The second resonance frequency may be an integer multiple of the first resonance frequency. By making the second resonance frequency an integer multiple of the first resonance frequency, it becomes easy to align the positions of the nodes. The actuator may be a piezoelectric element.

  Another aspect of the present disclosure is a vibration device including an actuator that generates vibration. The vibration device according to this aspect has a first resonance frequency and a second resonance frequency higher than the first resonance frequency, and resonates simultaneously at the first resonance frequency and the second resonance frequency. By simultaneously resonating in a plurality of resonance modes, the tip of the vibration device can take various vibration trajectories.

DESCRIPTION OF SYMBOLS 1 ... Ultrasonic vibration cutting device, 6 ... Work material, 10 ... Ultrasonic vibration device, 11 ... Cutting tool, 12 ... Vibration device, 13a, 13b ... Piezoelectric element, 20 ... control unit, 30 ... drive device, 31 ... oscillator, 32 ... amplifier.

Claims (5)

A vibration cutting device including a vibration device including an actuator that is mounted with a cutting tool and generates vibration, the vibration device having a first resonance frequency and a second resonance frequency higher than the first resonance frequency. Resonate simultaneously at the first resonance frequency and the second resonance frequency,
A vibration cutting apparatus characterized by that. A driving device that applies a voltage to the actuator to reciprocally vibrate the cutting edge of the cutting tool in one direction;
A control unit for controlling the voltage applied by the driving device,
The control unit controls the voltage applied by the driving device so that the vibration device resonates simultaneously at a first resonance frequency and a second resonance frequency.
The vibration cutting device according to claim 1. The second resonance frequency is an integer multiple of the first resonance frequency.
The vibration cutting apparatus according to claim 1 or 2, wherein The actuator is a piezoelectric element.
The vibration cutting device according to any one of claims 1 to 3, wherein A vibration device including an actuator that generates vibration, having a first resonance frequency and a second resonance frequency higher than the first resonance frequency, and resonating simultaneously at the first resonance frequency and the second resonance frequency.
A vibration device characterized by that.

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