JPH0643019B2 - Vibration processing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vibration machining method for machining a workpiece by driving a tool that vibrates in the vertical direction by driving an electrostrictive oscillator against the surface of the workpiece.

[Prior Art] As a vibration machining method of this type, ultrasonic machining is generally known. Ultrasonic processing is a processing method in which a tool is attached to an amplitude-enhancing horn that is connected to a vibrator, and the tool is pressed against the workpiece while performing longitudinal vibration resonance as a whole. Used to do.

[Problems to be solved by the invention]

However, ultrasonic machining has a drawback that the exchangeability of tools is severely restricted. The reason is that ultrasonic machining attaches a horn to which a vibrator is coupled as described above and causes resonance as a whole.To obtain such resonance, the tool is determined by its density and longitudinal elastic coefficient. This is because the shape and the length must be changed, and therefore, if the tool having a different shape and length other than the resonance frequency is replaced, resonance cannot be obtained and machining cannot be performed.

For this reason, only a limited number of tools can be used in ultrasonic machining, and when the workpiece has a complicated shape such as a die, various tools that can handle various parts of the shape can be used. It is difficult to use, and thus, until now, the problem has not been solved, and only a relatively simple shape of tool tool is machined with a few tools.

Therefore, an object of the present invention is to eliminate the above-mentioned drawbacks and to provide a vibration machining method capable of adopting various tools depending on the properties of the workpiece and the machining purpose.

[Means for solving problems]

The present invention relates to a vibration system in which a joint is integrally coupled to a laminated electrostrictive oscillator in which a plurality of piezoelectric bodies are laminated and displacement is obtained as a sum of amplitudes of the respective piezoelectric bodies, and the joint is exchangeably coupled by screw tightening. Machining a workpiece by vibrating the tool in a vertical direction while driving the vibration system at a driving frequency lower than its natural frequency using a vibration machining means equipped with a tool and pressing the tool against the surface of the workpiece. The present invention relates to a vibration processing method characterized by performing

If the machining is performed in this way, the vibration system is driven at a driving frequency lower than its natural frequency so that the vibration system and the tool do not resonate as a whole.
It is possible to replace the length tool with a wide range according to the output of the electrostrictive vibrator.

In the present invention, the use of a laminated type electrostrictive oscillator provides a high frequency and a large amplitude, thereby reducing the load and increasing the processing speed.
This is advantageous because the amplitude is not attenuated by the load and a constant amplitude is obtained regardless of the load fluctuation. They are,
This is an effect of the laminated piezoelectric displacement element having a structure in which a plurality of piezoelectric bodies are laminated and the displacement is taken out as the sum of the amplitudes of the respective piezoelectric bodies.

〔Example〕

 Next, examples of the present invention will be described.

The tool used in this vibration machining method employs various types of tools such as a grindstone, a file, a knife, and a lap rod according to the property of the workpiece and the purpose of machining. For example, with a shank as shown in FIG. A grindstone will be described below as a representative example. The tool 1 is replaceably coupled to a joint 2 by screwing, the joint 2 is integrally coupled to an electrostrictive oscillator 3, and one end of the electrostrictive oscillator 3 is attached to an inner bottom portion of a handheld cylindrical protective cover 4. A small hole 5 that is joined and provided at the tip of the protective cover 4 serves as a guide for the joint 2 that is inserted therethrough.
The electrostrictive vibrator 3 and the electrostrictive vibrator 3 constitute a vibration system 6. Reference numeral 7 is an oscillator that gives a drive frequency to the electrostrictive oscillator 3.

In this example, a laminated piezoelectric displacement element is used as the electrostrictive oscillator 3, and the tool 1 is subjected to vibrations of a frequency of about 50 to 20,000 Hz, preferably about 1,000 to 20,000 Hz, and an amplitude of about 5 to 50 microns. It is designed to be granted. Various types of laminated piezoelectric displacement elements are adopted, for example, trade name:
A typical example is a laminated piezoelectric actuator (manufactured by NEC Corporation). Voltage applied to this laminated piezoelectric displacement element:
It was driven by applying 100 VDC of Hz direct current.

This drive is performed at a drive frequency lower than the natural frequency of the vibration system 6. The natural frequency of the vibration system 6 can be obtained by tapping the entire vibration system 6 excluding the tool 1 in the axial direction and measuring the frequency of minute displacement. The natural frequency of the drive system 6 thus obtained was 30 KHz.

Then, the displacement of the laminated piezoelectric displacement element causes a weight of 5 g.
The tool 1 of No. 1 was vibrated vertically. The respective vibrations when the drive frequencies are different are shown in FIG. As shown in FIG. 2, the driving frequency is 50, 100, 300, 5
At 00 and 1000 Hz, the respective amplitudes are 30, 3
0, 29, 28 and 25 microns. In this way, even if the drive frequency was changed, all the tools 1 vibrated following the drive frequency well, and the vibration of the tool 1 did not change so much.

Next, the tools of various weights determined by different shapes and lengths were exchanged, and the vibration system 6 was driven at a voltage of 1000 Hz and a direct current of 130 V. The respective vibrations when the weight of the tool is different are shown in FIG. It is shown in FIG. As shown in FIG. 3, when the tool weights were 5, 20, 35 and 50 g, the respective amplitudes were 30, 27, 25 and 23 microns.
Even when the tool weight was changed in this way, any of the tools 1 vibrated well following the applied drive frequency, and an amplitude sufficient for practical use was obtained. Then, as shown in FIG. 1, when the tool 1 was pressed against the workpiece surface 8 to perform the machining of the workpiece, the machining could be performed at a satisfactory machining speed in any case. .

When the driving frequency is given to match the natural frequency of the vibration system 6, the vibration system 6 and the tool 1 resonate and vibrate only because they have the same natural frequency.
The tool 1 having a natural frequency different from the natural frequency of the vibration system 6 could not be vibrated. However, according to the above-mentioned example, since the vibration system is driven at a driving frequency lower than its natural frequency, there is no restriction on the length or shape of the tool, and the range may be in accordance with the output of the laminated piezoelectric displacement element. Therefore, a wide range of tools can be used.

〔The invention's effect〕

According to the present invention, the vibrating system is driven at a driving frequency lower than its natural frequency so that the vibrating system and the tool do not resonate as a whole, so that tools having different shapes and lengths are exchanged over a wide range. be able to. Further, since the displacement of the electrostrictive vibrator can be directly converted into the displacement of the tool by connecting the tool to the joint connected to the electrostrictive vibrator by tightening the screw, the energy transfer efficiency is improved. Further, since the electrostrictive vibrator is a laminated type in which a plurality of piezoelectric bodies are laminated and displacement is obtained as the sum of the amplitudes of the respective piezoelectric bodies, a high frequency and a large amplitude are obtained, which reduces the load and reduces the machining. The speed can be increased, the amplitude is not attenuated by the load, and a constant amplitude can be obtained regardless of the load fluctuation.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a vibration machining means used in the method of the present invention, FIG. 2 is a diagram showing a relation between amplitude and drive frequency, and FIG. 3 is a diagram showing a relation between amplitude and tool weight. Further, in the reference numerals used in the drawings, 1 is a tool, 2 is
Is a joint, 3 is an electrostrictive oscillator, 4 is a protective cover, 5 is a small hole,
6 is a vibration system, 7 is an oscillator, and 8 is a workpiece surface.

Claims (1)

[Claims] 1. A vibrating system in which a joint is integrally connected to a laminated electrostrictive oscillator in which a plurality of piezoelectric bodies are laminated and displacement is obtained as a sum of amplitudes of the respective piezoelectric bodies, and the joint is exchangeable by screwing. Using a vibration machining means equipped with a coupled tool, the tool is vibrated in the up-and-down direction while driving the vibration system at a drive frequency lower than its natural frequency, and the tool is pressed against the surface of the work piece. A vibration machining method characterized by performing the machining of.