JPH0219741B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a mold vibration device for continuous casting.

Continuous casting involves continuously casting molten steel or other metal in a mold while cooling it and solidifying it into the desired shape. During this casting process, the mold and cast metal are prevented from seizing or sticking. Therefore, the mold is vibrated.

In order to vibrate the mold, a required number of actuators are placed around the mold, and these actuators are synchronously driven in the vertical direction at the required amplitude and frequency.

Conventional vibration devices for vibrating molds include a mold vibration device using a circular eccentric cam using an electric motor, and a hydraulic servo type mold vibration device using a hydraulic cylinder. There are drawbacks as shown below.

(i) Mold vibrating devices using circular eccentric cams and mold vibrating devices using hydraulic servo cylinders have a limited mechanical frequency response. synchronization is broken and cannot be put to practical use. For this reason, the maximum frequency of conventional mold vibration devices is limited to 2 to 3 Hz, and at such vibration frequencies it is not possible to sufficiently prevent seizure and sticking, and at the same time, unevenness remains on the surface of the slab, making it difficult to cast slabs with a uniform surface. It was difficult to get it out.

(ii) In the above-mentioned two-vibration device, a large load is applied to the vibrating device because the vibrating device suddenly enters a steady operating state and a stopped state when the vibrating operation starts and stops.

(iii) In the above-mentioned two-vibration device, it is difficult to change the settings of the vibration frequency and amplitude value during the vibration operation, and it is especially impossible to change the settings in the circular eccentric cam system.

(iv) Since the hydraulic servo cylinder method uses analog amplifiers, etc., the amplitude center shifts and frequency disturbances occur due to drift.

The present invention has been made to correct the above-mentioned drawbacks of the conventional device, and uses a digital step cylinder as an actuator to enable digital control of vibration, thereby significantly increasing the vibration frequency and reducing the vibration conditions during vibration operation. This aims to improve the smoothness when starting and stopping vibration operation.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 schematically shows a vibration device according to the present invention, in which a mold 1 is attached to a vibration table 2, and the vibration table 2 is supported by left and right digital step cylinders (hereinafter abbreviated as digital cylinders) 3 and 4. ing.

The oil flow necessary for the digital cylinders 3 and 4 is supplied from a hydraulic source 5, and the driving of the digital cylinders 3 and 4 is controlled by a control device 6. Further, the digital cylinders 3 and 4 are each equipped with a position detector 7 for detecting the amount of protrusion of the cylinder rod.
8 is provided to detect the state of movement of the digital cylinders 3 and 4 and input the signal to the control device 6.

Here is a brief explanation of the digital cylinder:
This hydraulic cylinder has a built-in control valve, and the amount of protrusion of the cylinder rod is determined by the position of the control valve.The control valve is moved and positioned by an electric pulse motor via a ball screw. The amount of movement of the cylinder rod is determined by the number of pulses input to the pulse motor, its stopping accuracy is ±1 pulse, and the speed of movement is determined by the frequency of the input pulses. Therefore, the manner of movement of the digital cylinder can be freely controlled by applying pulses.

Furthermore, since the movement of the digital cylinder is guaranteed by the input pulse, even when driving a plurality of digital cylinders, highly accurate synchronization can be achieved by applying the same pulse.

FIG. 2 is a block diagram showing the configuration of the apparatus of the present invention, and the same components in FIG. 2 as in FIG. 1 are given the same reference numerals.

The control device 6 mainly includes an input relay circuit 9, an A/D converter 10, an input buffer circuit 11, a microcomputer 12, an output buffer circuit 13, a cylinder drive circuit 14, and an output relay circuit 15. frequency setter 1
6. Amplitude value setter 17 and vibration frequency reading push button 18, amplitude value reading push button 19, vibration start push button 2
0 and vibration stop push button 21 are connected, respectively, and A/
Left and right position detectors 7 and 8 are connected to the D converter 10.

Further, the output relay circuit 15 is connected with lamps such as a vibration operation ready indicator lamp 22, a vibration operation in progress indicator lamp 23, and a digital cylinder synchronization status indicator lamp 24, and the output buffer circuit 13 is connected with a frequency value indicator 25 and an amplitude value indicator A display 26 is connected to the cylinder drive circuit 14, and step motors 27 (see FIG. 1) for the left and right digital cylinders 3 and 4 are connected to the cylinder drive circuit 14, thereby configuring the mold vibrating device of the present invention.

As mentioned above, the digital cylinders 3 and 4, which are the actuators of this device, can be driven by digital control, and the vibration conditions, that is, the vibration waveform, can be determined by determining the input state of the pulse signal by software.
A waveform of arbitrary frequency and amplitude can be obtained and easily changed.

The microcomputer 12 calculates a vibration waveform based on the frequency and amplitude values set and input from the frequency setter 16 and the amplitude value setter 17 according to the input program, and calculates the vibration waveform from the digital cylinders 3 and 4.
A pulse signal that causes an operation that satisfies the set frequency and amplitude conditions is input to the cylinder drive circuit 14, and the drive circuit 14 converts this pulse signal into a pulse signal for driving the digital cylinders 3 and 4. and input it to digital cylinders 3 and 4.

Here, the vibration waveform and the microcomputer 12
The relationship with the pulse signal Pn output from the Pn will be explained with reference to FIG.

Here, the type of vibration waveform is a sine wave.

When the vibration waveform a is made up of a predetermined number of pulses, by setting the frequency and amplitude value, a sinusoidal vibration waveform a is calculated as shown in FIG. 3, and the pulse interval tn (time ), number of pulses
Zn is calculated. Therefore, cylinder drive circuit 1
4 outputs a drive signal with a number of pulses sufficient to form the vibration waveform a at predetermined time intervals to the left and right digital cylinders 3 and 4.

Furthermore, the frequency and amplitude values can be easily changed by changing the pulse interval and the number of pulses.

Furthermore, when starting, stopping, changing the frequency, or changing the amplitude value, it is possible to create a transient state using software so that these changes can be made smoothly.

For example, at startup, as shown in Figure 4 (a), a transient state b is set in which the frequency and amplitude values gradually increase from the startup to a steady state, and when changing the frequency, the frequency is set as shown in Figure 4 (b). In the case of changing the amplitude value, a transient state b is set in which the amplitude value gradually changes as shown in FIG. 4C.

These transient states b can also be easily created by determining the pulse interval and number of pulses according to preprogrammed conditions.

Note that the above-mentioned case applies to intentionally changing the vibration waveform, but there is a dynamic characteristic that generally when the frequency is increased, the gain of the output of the drive circuit 14 decreases and the amplitude becomes smaller than the set value. If the computer 12 includes a dynamic characteristic correction circuit that compensates for a decrease in gain due to an increase in frequency, it is possible to maintain the amplitude value at a set value regardless of an increase in frequency.

Next, the flow of operation will be explained based on FIG.

First, set a predetermined frequency and amplitude value using the frequency setter 16 and the amplitude value setter 17, and input the set values by operating the vibration frequency read button 18 and the amplitude value read push button 19.The relay circuit 9 and the input buffer circuit Microcomputer 1 through 11
Enter 2. The microcomputer 12 calculates the vibration waveform as described above based on the input setting values, determines the time interval of pulses and the number of pulses so that the vibration waveform is formed, enables output, and sets the transient state. .

Vibration is started by operating the vibration start push button 20.
By operating the vibration activation push button 20, a signal output from the microcomputer 12 is converted into a driving pulse signal by the cylinder drive circuit 14 and input to the left and right digital cylinders 3 and 4. The left and right digital cylinders 3 and 4 move in accordance with the input pulses to vibrate the vibration table 2.

Since the digital cylinders 3 and 4 move in accordance with the pulses as described above, they can be driven with extremely high synchronization accuracy as long as pulses are input to both digital cylinders 3 and 4 under the same conditions.

The movements of the left and right digital cylinders 3 and 4 are inputted to the microcomputer 12 by the left and right position detectors 7 and 8 via the A/D converter 10 and the input buffer circuit 11, and the microcomputer 12 calculates the synchronization state. The calculation result is displayed on the cylinder synchronization state display lamp 24 via the output buffer circuit 13 and the output relay circuit 15.

In addition, the vibration operation ready indicator lamp 22 indicates that the device is ready for operation.
Reference numeral 3 indicates that the apparatus is in operation, and a frequency value display 25 and an amplitude value display 26 are provided to inform the operator whether or not the set values are accurate.

When the device is desired to be stopped due to completion of casting or for other reasons, the vibration stop push button 21 is operated.
Even when it stops, it gradually stops after going through a transient state according to a command from the microcomputer 12.

As described above, according to the present invention, (i) the vibration frequency can be significantly increased compared to the conventional one due to high response and good synchronization; (ii) the vibration frequency and amplitude can be changed at any time and Settings can be changed as many times as desired; (iii) The digital control system simplifies the circuit; (iv) When vibration conditions change, such as when starting or stopping, a transient state can be created, so starting It has excellent effects such as reducing the load during operation and stopping, and allowing a smooth transition to steady operation and stop conditions.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a vibration device according to the present invention, and FIG.
3 is a diagram showing the relationship between vibration waveforms and pulse signals, and FIGS. 4A, 4B, and 4C are explanatory diagrams showing the process of changing the vibration waveform. 1 is a mold, 2 is a vibration table, 3 and 4 are digital step cylinders, and 6 is a control device.

Claims (1)

[Scope of Claims] 1. A vibration table on which a mold is installed is supported by a plurality of digital step cylinders, and a frequency setting device is provided for setting the vibration frequency, and an amplitude value setting device is provided for setting the amplitude value. , an input relay circuit, an input buffer circuit, and a vibration waveform is calculated based on the vibration frequency and amplitude values set and inputted from the frequency setter and the amplitude value setter through the input relay circuit and input buffer circuit, a microcomputer that outputs a pulse signal that causes the digital step cylinder to operate satisfying conditions of a set vibration frequency and amplitude value; 1. A mold vibrating device for continuous casting, characterized in that a control device is connected to the digital step cylinder, and includes a cylinder drive circuit that converts the signal into a pulse signal for driving the step cylinder and inputs the pulse signal to the digital step cylinder.