JPS6318233A - Measurement of unbalanced point and instrument for the same - Google Patents

Abstract

PURPOSE:To enable an unbalanced point to be positioned with a high accuracy by filtering vibration detection signals by a tracking band-pass filter and taking out only unbalance signals. CONSTITUTION:Unbalance signals obtained from a tracking band-pass filter 4 are inputted to a waveform shaping circuit 6 to obtain unbalance phase signals in synchronism with the revolution of an unbalanced point. The unbalance phase signals are inputted to an unbalance synchronous signal generating circuit 11 to obtain unbalance synchronous signals having a prescribed phase difference from the unbalance phase signals. When a driving device is slowed down under the control of a control DC voltage, the unbalance synchronous signals in synchronism with the unbalance phase signals are generated in the circuit 11 and the phase of the unbalanced point can be seized. Further, since the unbalance synchronous signals can be generated based on a stored synchronous condition by outputting a storage command from a controller 8 to a storage circuit 17 just before slowing down, the unbalanced point can be determined until a low speed just before a stop is reached. Then, when a stop command is inputted to a delay circuit 7, braking can be applied with a timing matched with the unbalance synchronous signals and the unbalanced point can be positioned with a high accuracy.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention detects unbalance points in rotating bodies that require rotational balance, such as rotors of electric motors, fans, rotating shafts, etc., and performs corrective processing. The present invention relates to a method for measuring an unbalance point and a positioning device used for this purpose.

(Prior art) Conventional no-marking, no-sensor one type is disclosed in, for example, Japanese Patent Application Laid-Open Nos. 132641/1982, 30924/1980, 4839/1983, and 17832/1983.
It is disclosed in No. 9. In these methods, the stepping motor pulse that drives the object to be measured is triggered by an unbalanced phase signal, the pulse is input to a preset counter that has already been preset, and when the count is up, the motor is stopped and the unbalanced position is brought to a fixed point. It is configured to stop.

However, with the above method, there is a problem of slippage between the belt and the object to be measured that occurs during deceleration, and precise positioning cannot be performed.In order to solve this problem, the following method is proposed. it was thought.

Method (2) is a method in which the rotational movement of the object to be measured is transmitted to a rotary encoder through a belt, and the output pulses of this rotary encoder are input to a preset counter to perform positioning.

Method (2) involves directly scraping the outer circumferential surface of the object to be measured during measurement rotation (approximately 600 rpm) using an unbalanced phase signal.

The method is to drive a hammer into the hole and stop it.

(Problems to be Solved by the Invention) In the above method (■), the rubber belt for transmitting rotational motion becomes fatigued and stretches, and oil adheres to the belt, making it easy to slip. In addition, the belt acts in a direction that applies a brake to the rotation of the object to be measured, and mechanical interference with the object drive belt causes twisting, which adversely affects correction surface separation. The other problem is that the measurement method is complicated because it requires a rotary encoder, preset counter, etc., and the equipment used for that method is expensive.
The problem is that the tolerance of the outer diameter of the belt-driven object to be measured is expanded to twice the tolerance of the cumulative number of rotations from the time of measurement to the time of stopping, resulting in a large positioning error, and the synchronous rectification method required for precision measurement cannot be introduced. First, there is the problem that it can only be used for very rough measurements.

In addition, in the method (2) above, driving a wedge into the rotating body rotating at a rotation speed of about 6 oorpm to immediately stop it causes damage to the object to be measured and the measurement vibration detector, and impractical. There's a problem.

(Means for Solving the Problems) That is, in order to solve the above-mentioned problems, in the unbalance point measuring method according to the present invention, the object to be measured is rotated at high speed by a drive device controlled by an EJ signal. The vibration generated by the object to be measured is detected, and the vibration detection signal is filtered by a tracking bandpass filter whose center frequency is controlled by the control signal to extract only the unbalanced signal. By shaping the waveform to obtain an unbalanced phase signal and generating an unbalanced synchronization signal having a predetermined phase difference from this unbalanced phase signal, even if the rotation of the object to be measured is decelerated and shifted to low speed rotation, the hand-balanced state A measure was taken to determine the phase of the unbalanced point based on the v4 signal.

The unbalance point automatic positioning device according to the present invention includes a drive device controlled by a control signal, a vibration detector that detects vibrations generated by the object to be measured,
Is the center frequency controlled by the control signal? a tracking bandpass filter for extracting only an unbalanced signal from the vibration detector output signal, and a waveform shaping circuit for obtaining an unbalanced phase signal from the unbalanced signal;
generating an unbalanced synchronization signal controlled by the control signal and having a predetermined phase difference from the unbalanced phase signal, and storing a condition when the unbalanced phase signal and the unbalanced synchronization signal reach a predetermined phase difference and are synchronized according to a storage command; an unbalance synchronization signal generating circuit having a memory circuit for storing the unbalance synchronization signal; and a delay circuit receiving the unbalance synchronization signal and outputting a braking signal and a stop signal to the drive device to stop the unbalance point of the object to be measured at an arbitrary position according to a braking command. and a control device that controls the entire device by outputting the above-mentioned control signals, storage commands, and braking commands.

(Function) Therefore, according to the unbalance point measuring method according to the present invention, the object to be measured is rotated by a drive device, vibrations generated from the object to be measured are detected, and the vibration detection signal is transmitted to the center frequency of the object to be measured. Is it controlled to be the same as the rotation speed? If the signal is inputted to a tracking bandpass filter that has a B value, only the unbalance signal can be extracted even if the rotational speed of the object to be measured changes. The amount of unbalance can be obtained from the amplitude component of this unbalance signal, and the position of the unbalance point can be obtained from the phase component.

Therefore, after obtaining the unbalance amount from the amplitude component of the unbalance signal during high-speed constant rotation, if the drive device is decelerated by the control DC voltage, the frequency of the unbalance signal obtained by the vibration detector will also change, but the tracking bandpass filter Since the center frequency similarly changes following the change in the control DC voltage, from the tracking bandpass filter,
An unbalanced signal is always obtained. By shaping the waveform of this unbalanced signal, an unbalanced phase signal synchronized with the rotation of the unbalanced point can be obtained. Since an unbalanced synchronization signal having a predetermined phase difference from this unbalanced phase signal is generated, even if the object under test is decelerated and rotated at a low speed, an unbalanced synchronization signal can be obtained based on the unbalanced phase signal. Even if a slip occurs between the object to be measured and the drive device, the unbalance synchronization signal is not affected, and the phase at the unbalance point can be accurately measured.

According to the automatic unbalance point positioning device according to the present invention, as described above, the unbalance signal obtained from the tracking hand bus filter is input to the waveform shaping circuit.
An unbalanced phase signal synchronized with the rotation of the unbalanced point is obtained and inputted to an unbalanced synchronization signal generation circuit, and in the unbalanced synchronization signal generation circuit, based on the control signal and the unbalanced phase signal, the unbalanced phase signal and a predetermined generate an unbalanced synchronization signal with a phase difference of .

Here, when the control DC voltage is controlled to decelerate the drive device, the frequency of the unbalanced phase signal changes, but the unbalanced synchronization signal generation circuit generates an unbalanced synchronization signal synchronized with the unbalanced phase signal, The phase of the unbalanced point can be grasped. Here, if further deceleration control is performed, the unbalance signal will not be detected due to the sensitivity limit of the vibration detector, so just before that, the control device issues a storage command to the storage circuit to store the synchronization conditions at that time. After this time, even if the unbalanced phase signal is no longer input to the unbalanced synchronization signal generation circuit due to further deceleration, the unbalanced synchronization signal can be generated based on the stored synchronization condition instead of the unbalanced phase signal. The unbalance point can be detected until the speed reaches low speed just before stopping.

Next, when the control unit issues a stop command to the delay circuit, the delay circuit brakes in time with the unbalance synchronization signal, but since the rotation of the object to be measured at this time is extremely slow, No slip occurs even when braking suddenly, and the unbalanced point can be stopped at any desired position with high precision.

(Example) An example according to the present invention will be described in detail below with reference to FIGS. 1 and 2.

FIG. 1 is a block diagram of an embodiment according to the present invention, and FIG. 2 is a diagram showing the operation and waveforms of this embodiment.

The object to be measured 1 is rotated by a servo motor 2, the generated vibration is detected by a vibration detector 3, and the vibration detection signal is filtered by a tracking bandpass filter 4 to extract only the unbalance signal. When the rotation speed is constant, switch SWI is switched to input the unbalance amount from the unbalance signal to the unbalance amount display meter 5, which is stored and displayed.

After the unbalance amount measurement is completed, the unbalance signal is sent to the waveform shaping circuit 6.
to obtain an unbalanced phase signal synchronized with the rotation of the unbalanced point of the object to be measured. The unbalanced phase signal is input to the phase difference meter 12 of the unbalanced synchronization signal generation circuit 11.

This unbalanced synchronization signal generation circuit 11 includes a multiplier 15 that multiplies the control DC voltage from the control unit 8 and the output from the storage circuit 17, and outputs an unbalanced synchronization signal with a frequency corresponding to the output voltage of the multiplier 15. a voltage-frequency converter 16 that receives the unbalanced synchronization signal from the voltage-frequency converter 16 and the unbalanced phase signal, and a phase difference meter 12 that outputs the phase difference between the two signals; An integrator 13 that integrates the output, an arithmetic circuit 14 that performs an operation on the output of the integrator 13 so that both the signals have a predetermined phase difference, and an arithmetic circuit 14 that normally outputs the input signal as it is, but with an unbalanced phase due to a storage command. It consists of a storage circuit 17 that stores conditions when the signal and the unbalanced synchronization signal are synchronized, and these multiplier 15, voltage-frequency converter 16, phase difference meter 12, integrator 13, arithmetic circuit 14, and storage circuit. 17 forms a kind of phase-locked loop that synchronizes the unbalanced phase signal and the unbalanced synchronization signal to a predetermined phase difference.

For example, when the unbalanced synchronization signal and the unbalanced phase signal from the waveform shaping circuit 6 have a phase difference of 90°, the output of the phase difference meter 12 becomes a rectangular wave with a duty ratio of 50%, and the output voltage of the integrator 13 is 0. So, when the phase difference is different from 90°,
The output of the integrator 13 outputs a voltage according to the phase difference, and the arithmetic circuit 14 works to make the output voltage OV, thereby always maintaining a 90° phase difference between the unbalanced phase signal and the unbalanced synchronization signal. .

As mentioned above, in the unbalance synchronization signal generation circuit 11, the unbalance synchronization signal synchronized with the rotation of the unbalance point of the object to be measured 1 is always obtained, so after the unbalance amount measurement is completed, the control DC voltage is controlled to control the servo Decelerate motor 2; unbalance phase signal and unbalance amount when controlling ti'! Even if the phase difference of the iIl signal deviates by 90 degrees, it is fixed to the 90' position +:0 difference by the action of the front three convex and D phase locking loops. here,
If further deceleration control is performed, the unbalance signal will not be detected due to the sensitivity limit of the vibration detector 3, so the f-speed control will be
il'' device 8 issues a storage command to the storage circuit 17 to store the conditions of the same month at that time.After this time, the unbalanced phase signal is further decelerated and the unbalanced synchronization signal generation circuit 1
1, an unbalanced synchronization signal can be generated based on the stored synchronization conditions instead of the unbalanced phase signal, so the unbalanced point can be grasped until low speed rotation immediately before stopping.

Here, when the control unit 8 issues a stop command to the delay circuit 7,
The delay circuit 7 controls the drive control circuit 18 and brakes the servo motor 2 in synchronization with the unbalance synchronization signal. Since the rotation of the object to be measured 1 at this time is relatively slow, no slip occurs between the servo motor 2 and the object to be measured 1 even if sudden braking occurs in a short period of time. It can be stopped in position with high precision.

To explain the main functions of the control section 8, the control DC voltage signal from the control section 8 is converted by the voltage-frequency converter 10 of the drive control circuit 18 into a signal with a frequency corresponding to the control DC voltage signal. , the signal is input to the servo motor driver 9 of the drive control circuit 18 and the servo motor 2
The rotation speed of the motor is controlled by the control DC voltage signal.

Further, since the control DC voltage signal from the control unit 8 is also input to the center frequency control voltage input terminal of the tracking bandpass filter 4, as well as the voltage-frequency converter 10, rotation of the object to be measured 1 is possible. When changing the control DC voltage to change the number of vibrations, the frequency of the unbalance signal obtained from the vibration detector 3 also changes, but the center frequency of the tracking bandpass filter 4 similarly follows the change in the control DC voltage. Therefore, only the unbalanced signal component is always obtained from the tracking bandpass filter 4.

Here, the operation of each part will be explained based on FIG. 2.

The unbalanced signal that is the output of the tracking bandpass filter 4 from measurement high speed rotation to just before stopping is (a), and the unbalanced phase signal whose waveform is shaped by the waveform shaping circuit 6 is represented by (b), and the unbalanced synchronization The waveform of the unbalanced synchronization signal obtained from the signal generation circuit is (c), and the output waveform from the phase difference meter 12 is (d). Further, the time chart for unbalance amount measurement is shown in (e), the time chart for unbalance phase measurement is shown in (f), and the time chart for braking by the delay circuit 7 is shown in (g).

First, when rotating at a predetermined constant speed, close the switch SWI and measure the amount of unbalance. After the measurement is completed (Tl), reduce the rotation speed of the servo motor (Q) to the lowest rotation speed at which an unbalance signal can be detected. The phase of the unbalance point is determined by the unbalance synchronization signal, and the conditions for synchronization are stored in the storage circuit 17 by a storage command from the control section 8.

Next, the delay circuit 7 is activated by a stop command from the control section 8 (T2), and the unbalance point is stopped at an arbitrary position by rotating by a predetermined angle (T3).

In addition, if a marking device consisting of an electromagnetic solenoid and a stamp is installed at an arbitrary position to mark the position of the unbalanced point on the outer circumferential surface of the object to be measured, the right marking device will mark the right unbalanced point. After that, the right and left phase difference measurement object 1 is rotated by the servo motor 2, and the left unbalance point is stopped at the position of the left marking device and marked, and the object to be measured is removed from the unbalance measurement pedestal. However, never lose sight of the imbalance.

Furthermore, the unbalance point measuring method according to the present invention and the apparatus used in the method are equipped with a synchronous rectification measuring circuit 19, as shown by the dashed line in FIG. be able to. At this time, when the unbalanced synchronization signal and the unbalanced phase signal complete synchronization, switch S
Switch to the synchronous rectification measurement circuit 19 using WI, switch SW2, and switch SW3, measure the amount of unbalance, and obtain an unbalance synchronization signal in the synchronous rectification measurement circuit 19 until just before stopping, thereby measuring the amount of unbalance and positioning the unbalance point. I can do it accurately after drinking.

(Effects of the Invention) According to the unbalance point measuring method according to the present invention, the center frequency of the tracking bandpass filter and the rotation speed of the object to be measured are controlled in conjunction with each other, and an unbalance synchronization signal synchronized with the unbalance phase signal is generated. Since it decelerates while moving, it is possible to measure the phase at the unbalanced point without being affected by slip between the drive device and the measured object.It is a no-sensor, no-marking method, and does not require a precent counter or rotary encoder. This has the advantage that unbalance point measurement can be performed with high precision and the measurement method is simple.

Another advantage is that a synchronous rectification measurement method suitable for highly accurate measurement can be adopted.

Further, according to the automatic unbalance point positioning device according to the present invention, as described above, it is a no-sensor, no-marking system and does not require a preset counter or rotary encoder, so the automatic unbalance point positioning device can be made at low cost. In addition to being effective, by memorizing the conditions when the unbalanced phase signal and the unbalanced synchronization signal are synchronized, the phase of the unbalanced point can be measured until the rotation of the measured object is about to stop, and the measured object can be braked. Since no slip occurs between the object to be measured and the drive device even when the device is stopped, there is an effect that the unbalance point can be positioned with high precision. Further, by applying the synchronous rectification measurement method, it is possible to position the unbalanced point with even higher precision.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating the seventh embodiment of the present invention, and FIG. 2 is a diagram showing the operation and waveforms of this embodiment.

Claims (2)

[Claims] (1) The object to be measured is rotated at high speed by a drive device controlled by a control signal, vibrations generated by the object to be measured are detected, and a tracking bandpass filter whose center frequency is controlled by the control signal is used. The vibration detection signal is filtered to extract only the unbalanced signal, this unbalanced signal is waveform-shaped to obtain an unbalanced phase signal, and an unbalanced synchronization signal having a predetermined phase difference from this unbalanced phase signal is generated. An unbalance point measuring method, characterized in that the phase of the unbalance point can be determined based on the unbalance synchronization signal even if the rotation of the object is decelerated to a low speed rotation. (2) a drive device controlled by a control signal; a vibration detector that detects vibrations generated by the object to be measured; and a center frequency controlled by the control signal, and an unbalance signal from the output signal of the vibration detector. a tracking bandpass filter for extracting only the unbalanced phase signal; a waveform shaping circuit for obtaining an unbalanced phase signal from the unbalanced signal; and an unbalanced synchronization signal that is controlled by the control signal and has a predetermined phase difference from the unbalanced phase signal. an unbalanced synchronization signal generation circuit having a storage circuit that stores a condition when the unbalanced phase signal and the unbalanced synchronization signal have a predetermined phase difference and are synchronized by a storage command, and captures the unbalanced synchronization signal by a stop command; Consists of a delay circuit that outputs a stop signal to the drive device to stop the unbalanced point of the object to be measured at an arbitrary position, and a control device that controls the entire device by outputting the above control signal, storage command, and stop command. Unbalance point automatic positioning device.