JPH0584644A - Vibration suppressing device - Google Patents

Abstract

PURPOSE:To provide a vibration suppressing device for automatically and properly suppressing vibration of a workpiece following a change such as at the time of changing a machining condition due to changing wearing condition of cutting tool, grinding wheel, etc., and at the time of changing the workpiece. CONSTITUTION:A device is characterized by providing a workpiece vibration exciting means 2 brought into contact with a workpiece by detecting its vibration with a workpiece vibration detecting sensor 3, comprising a detecting pin 3c brought into contact with the workpiece in a machining position and a detecting member 3b for detecting advance/retract displacement measured of this detecting pin 3c, and by generating amplitude and its periodic motion equivalent to amplitude and its periodic motion of the workpiece by a piezoelectric actuator 2c based on a detection signal by this workpiece vibration detecting sensor 3 and a controller for controlling this workpiece vibration exciting means 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration suppressing device for damping the vibration of a work being machined by a machine tool.

[0002]

2. Description of the Related Art Vibration (chatter) is generated in a workpiece machined by a machine tool due to cutting, grinding resistance or the like. In order to reduce this, the pressing force of the chatter stopper against the work is changed, and the position of the chatter stopper and the material of the chatter stopper metal are searched and arranged by trial and error in order to match the vibration of the workpiece.

[0003]

However, when the machining conditions change due to changes in the wear state of the bite, grindstone, etc., or when the work changes, it is not possible to suppress the vibration by following it. Each time, it is necessary to change the pressing force or to search for a vibration generation site and provide a chatter stop.

An object of the present invention is to provide a vibration suppressing device which detects a vibration of a work and forcibly applies a vibration action corresponding to the vibration to the work to damp the vibration of the work.

[0005]

SUMMARY OF THE INVENTION A feature of the present invention for achieving the above object is to provide a fixed frame, a detection pin which is held by the fixed frame so as to be movable back and forth, and which comes into contact with a work, and the detection pin. Of the work vibration detection sensor, which is composed of a detection means for detecting the forward / backward displacement of the work, and is movably supported by the fixed frame so as to move back and forth on the basis of the detection signal from the work vibration detection sensor. And a work vibrating means including a vibrating member that generates an amplitude and its periodic motion to contact the work.

[0006]

With the above structure, the work vibration detecting sensor detects the vibration of the work, and the work vibrating means abutting against the detection signal gives the work an amplitude equivalent to the vibration of the work. The vibration of the work is damped by suppressing the amplitude of the work.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a first embodiment of the present invention. In FIGS. 1 and 2, 1 is a fixed frame, 2 is a work vibrating means, and 3 is a work vibration detection sensor.

The work vibrating means 2 holds a cylindrical vibrating member 2a (cylindrical, rectangular tube, etc.) so that it can be moved back and forth with respect to the fixed frame 1 and is always biased in the backward direction by a pressing spring 2b. The piezoelectric actuator 2c provided between the vibrating member 2a and the fixed frame 1 is configured to push in the forward direction.

The work vibration detecting sensor 3 has a cylindrical holder 3a at the center of the vibrating member 2a of the work vibrating means 2.
Is fitted in the coaxial line direction, the end of the holder 3a is fixed to the fixed frame 1, the detecting member 3b such as a differential transformer is housed inside, and the tip of the holder 3a projects from the end face of the vibrating member 2a. The detection pin 3c is connected to the detection member 3b. ..

FIGS. 3 and 4 show a second embodiment of the present invention. In this second embodiment, the interior of the fixed frame 1 is divided into partition walls 1a.
The chamber is divided into upper and lower parts with a cylindrical vibrating member 2a in the lower chamber.
And a work vibrating means 2 composed of a pressing spring 2b for constantly biasing the vibrating member 2a in the backward direction and a piezo actuator 2c, and a work composed of a detecting member 3b and a detecting pin 3c in the upper chamber. This is a configuration in which the vibration detection sensor 3 is arranged.

FIG. 5 is a view showing an example in which the vibration suppressing device 7 according to the first embodiment of the present invention is used in a machine tool 4, 5 is a grindstone of the machine tool 4, and W is a workpiece machined by the grindstone 5. Is. Reference numeral 6 denotes a support frame that supports the vibration suppressing device 7, and the two vibration suppressing devices 7 are attached to the supporting frame 6.
It is arranged in a direction intersecting the axis of the work W at a right angle. Reference numeral 8 denotes an advancing / retreating cylinder for moving the vibration suppressing device 7 forward / backward with respect to the work W.

Reference numeral 9 denotes a servo driver, which is connected to the piezo actuators 2c of the respective vibration suppressing devices 7. A sensor controller 10 is connected to the detection member 3b of each of the vibration suppressing devices 7. 1
1 is a central processing unit, which is a read-only memory 12
(ROM 12) and random access memory 13 (RA
M13) is connected so as to be able to input / output, output to the servo driver 9 and input from the sensor controller 10. The ROM 12 stores a program for executing the vibration suppressing devices 7 and 7a, which will be described later, and a program necessary for data processing. The RAM 13 has an area for storing sensor data and data calculated in the data processing process. Has been formed.

FIGS. 6 and 7 are views showing an example in which the second embodiment of the present invention is used in a machine tool, in which 14 is a workpiece mounting jig, 5a is a milling cutter, and W is the workpiece mounting jig. It is a work attached to 14. The vibration suppressing device 7a is arranged by the advancing / retreating cylinder 8 so as to be capable of advancing / retreating so as to come into contact with the workpiece W attached to the workpiece attaching jig 14. The control means of the vibration suppressing device 7a in the second embodiment is the same as that in the first embodiment.

The operation of the vibration suppressing devices 7 and 7a according to the present invention will be described below with reference to the flowchart of FIG. First, as a pretreatment, the vibration suppressing devices 7 and 7a are moved forward to bring the detection pin 3c into contact with the work W. In processing the work W, the frequency of the work W is detected (100). The vibration of the work W is a combination of various waveforms having various frequencies, and this is detected as a voltage change by the sensor data processing program in the detection member 3b, the sensor controller 10 and the ROM 12, and this detection is performed. The waveform is converted into Asin ωt [A: amplitude, by Fourier transform (102) by the Fourier transform program in the ROM 12.
ω: frequency].

Next, the initial operation command value is output (104). This may simply give the waveform -Asin ωt that is the reverse of the waveform of the waveform detection (102), or empirically give the form of Bsin (ωt + θ) [B: amplitude, θ: phase difference]. Good.

The waveform of the output (104) of the initial operation command value is subjected to inverse Fourier transform (106) by the inverse Fourier transform program of the ROM 12, and the piezo actuator 2
It is the point group command value of c. Based on this point cloud command value, the vibration suppressing operation of the work W is executed by the operation execution program in the ROM 12 (108). The vibrating member 2a is moved forward by the piezo actuator 2c to come into contact with and press the work W. Then, the vibration during the execution is detected (11
0) and Fourier transform (112) of the waveform.

Next, the waveform C of the Fourier transform (112)
It is determined (114) whether the amplitude of sin ω't [C: amplitude, ω ': frequency] is within a preset allowable value. If this determination is YES, the current vibration state may be continued, so the vibration suppression operation is executed (108), and N
If it is O, the data correction program in the ROM 12
Calculate new amplitude and phase to decrease the amplitude (11
6) Do. That is, the operation of step 104 (or step 118 described later) is performed by comparing the vibration waveform of the work W subjected to the Fourier transform in step 102 with the damping waveform in step 110 after executing the vibration suppressing devices 7 and 7a. A new operation command waveform Dsin (ωt + φ) [D: amplitude, φ:
Phase difference] is calculated.

Then, the operation command waveform obtained by the amplitude / phase calculation (116) is output (118) and returned to the inverse Fourier transform (106) to reduce the vibration, in the same manner as described above, so as to reduce the vibration. Continue execution of 7a.

That is, the vibration of the work W is detected by the work vibration detection sensor 3, and the work vibrating means 2 is moved forward in accordance with the vibration of the work W based on the detection signal to suppress the amplitude of the work W and vibrate. Is attenuated.

[0020]

As described above, according to the present invention, the vibration of the work is detected by the work vibration detection sensor including the detection pin that abuts the work at the machining position and the detection means that detects the forward / backward displacement of the detection pin. , A work vibrating means for abutting the work by generating an amplitude equal to the amplitude of the work and its periodic motion and its periodic motion based on the detection signal by the work vibration detection sensor,
Even when the machining conditions change due to changes in the wear state of the cutting tool, grindstone, or when the work changes, the vibration of the work can be detected for each work and a motion to cancel this vibration can be applied. The vibration of the work can be automatically and properly suppressed. Therefore, it is not necessary to adjust the pressing force of the chatter stop each time, or to perform the troublesome work of searching for the vibration generation site and providing the chatter stop.

[Brief description of drawings]

FIG. 1 is a front view showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a front view showing a second embodiment of the present invention.

FIG. 4 is a sectional view taken along line BB of FIG.

FIG. 5 is a side view of an example in which the first embodiment of the present invention is used for a machine tool and a combined view of a controller.

FIG. 6 is a plan view of an example in which the second embodiment of the present invention is used in a machine tool.

7 is a partial cross-sectional side view of FIG.

FIG. 8 is an operation flowchart of the device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed frame 2 Work vibrating means 2a Vibrating member 2b Pressing spring 2c Piezo actuator 3 Work vibration detecting sensor 3b Detection member 3c Detection pin 9 Servo driver 10 Sensor controller 11 Central processing unit 12 Read only memory 13 Random access memory

Claims (1)

[Claims] 1. A work vibration detection sensor comprising a fixed frame, a detection pin which is held by the fixed frame so as to be able to move back and forth, and contacts the work, and a work vibration detection sensor which comprises a detection means for measuring the forward / backward displacement of the detection pin, and the fixed frame. A work vibrating member which is movably supported by the work vibrating member and which generates an amplitude and a periodic motion equivalent to the amplitude and the periodic motion of the work based on the detection signal from the work vibration detection sensor and abuts against the work. A vibration suppressing device comprising: a vibrating unit.