JPH0763825B2 - Oscillation device for continuous casting machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to an oscillation device of a continuous casting device.

[Prior Art and Process of the Present Invention] As is well known, in a continuous casting apparatus, for example, when the molten steel level reaches a predetermined level in the mold, a pinch roll operates to pull down the slab together with the dummy bar. . At the same time, the mold is rocked, that is, oscillated.

Such an oscillation operation is to prevent the cast slab from sticking to the inner surface of the mold, that is, to improve the peeling, and also to improve the surface quality of the cast slab. Is done for. Therefore, for such an operation, it is necessary to properly set the vibration condition according to the steel type, the size and shape of the cast piece, and the like.

By the way, conventionally, as an oscillation device, a mechanical oscillation device using an eccentric body and a hydraulic oscillation device using a hydraulic cylinder are known. For the former, for example, Japanese Patent Publication No. 52-25371. Gazette and Japanese Patent Publication Sho 5
As introduced in JP-A-2-35613, a continuously variable transmission for driving an eccentric body is interposed and the number of revolutions of the continuously variable transmission is controlled to change the frequency. However, an improved example of the latter is introduced in Japanese Patent Publication No. 51-48129.

Further, in the mechanical oscillation device, an attempt has been already made to match the casting condition by paying attention to the frequency of vibration (that is, focusing on the waveform of vibration) in the vibration condition. For example, according to Japanese Patent Publication No. 51-2053, at the beginning of the advent of continuous casting technology, anharmonic vibration, that is, a sawtooth waveform is proposed to prevent heat transfer reduction. The time distribution of the descending stroke (travel from top dead center to bottom dead center) and the ascending stroke in vibration is 3: 1.
Is said to be good. However, in the device for forming the sawtooth waveform, the acceleration is large, which causes a disadvantage that an unfavorable impact is generated in the casting process. Therefore, recently, the oscillation device for forming the sawtooth waveform is used. However, as explained, the majority of these devices are mold oscillating devices that vibrate at a sinusoidally changing speed.

However, according to the research conducted by the present inventors, for example, in a continuous casting machine for slabs, the mold lubricant (powdered additive) supplied to the mold flows between the mold and the solidified and shrunk surface of the slab. Observing the state of the mold, vibration of the mold due to the sawtooth waveform (of course, the purpose of the conventional sawtooth waveform and the time distribution between the descending step and the ascending step are different) is the surface texture of the slab. As a result of trial and error, the following inventions have been completed and are provided here.

It is also known that in a device using a hydraulic cylinder connected to a servo valve in the hydraulic oscillation device, vibration of an arbitrary vibration waveform can be obtained by appropriately controlling the servo valve, Such a device is not only expensive but also lacks in durability and repairability.

[Means for Solving Problems] Therefore, according to the present invention, an end portion of an oscillation rod connected to a mold is connected to an eccentric body, and the eccentric body is rotated to apply vertical vibration to the mold, and mold lubrication is performed. In the oscillation device of the continuous casting device, which is configured to add the agent, a hydraulic motor that rotationally drives the eccentric body, a detector that detects the rotational angle position of the eccentric body, and a control unit that controls the rotation of the hydraulic motor. A servo valve is provided between the hydraulic motor and the hydraulic source, and rotational angle position information from a detector that detects the rotational angle position of the eccentric body is input to the control unit. By outputting a command signal corresponding to the rotational angle position of the eccentric body to the servo valve, the rotational angular velocity of the eccentric body is changed during one cycle of vertical vibration of the mold, and a sawtooth vibration waveform is generated on the mold. By doing so, while overcoming the drawbacks of the conventional mechanical oscillation device, it also avoids the inconvenience of the hydraulic oscillation device. However, the present invention provides an oscillation device capable of forming a desired sawtooth waveform at any time during a casting operation.

[Embodiment] The configuration of the present invention will be described in detail below with reference to an embodiment shown in the accompanying drawings.

FIG. 1 is a model diagram showing an embodiment of the present invention, and FIG.
FIG. 3 is a graph showing a state in which the number of revolutions is changed by the apparatus shown in FIG. 3, and FIG. 3 is a graph showing a vibration waveform obtained by changing the number of revolutions in FIG.

In FIG. 1, the rotation of the hydraulic motor 20 is transmitted to the eccentric body 22 by the shaft 21, and the vertical vibration formed by the eccentric body 22 (for example, frequency 260 cycles / minute, stroke 4 mm).
Is transmitted to a mold (not shown) by the oscillation rod 23. A detector (for example, a rotary encoder or a pulse pip-up device) 24 that detects the rotation angle position of the eccentric body 22 is attached to the other end of the shaft 21. ) The rotation angle position is detected. The position of the shaft 21 is held by bearings 25, 25.

The rotation angle position information of the shaft 21 detected by the detector 24 is transmitted to the control unit 27. The control unit 27
Based on this rotation angle position information, a control signal is output to the servo valve 28 to drive the shaft 21 (eccentric body 22) to rotate at a rotation angular velocity corresponding to a preset rotation angle position, and the servo valve 28 is turned on. Via this, the hydraulic motor 20 is rotated at a predetermined rotational angular velocity. A speed increaser or a speed reducer may be interposed between the hydraulic motor 20 and the eccentric body 22 depending on the number of revolutions of the hydraulic motor 20 and the number of oscillations. In addition, 29 shows a hydraulic power source.

The oscillation device of this embodiment has the above-mentioned configuration.

Next, an example of how to give the rotation speed n to the hydraulic motor 20 will be described.

As shown in FIG. 2, from the bottom dead center to the top dead center of the eccentric body 22, the eccentric body 22 is rotated at a low rotation speed (angular velocity) n1, and then,
High rotational speed (angular velocity) n2 from top dead center to bottom dead center
Rotate quickly with. The time distribution is preferably 3: 1, but such distribution can be easily and accurately performed by a control command from the control unit 27 to the servo valve 28.
By controlling the rotation of the hydraulic motor 20 in this way, the vibration waveform of the mold can be obtained as a sawtooth waveform as shown in FIG. 3, for example. Therefore, by combining various time ratios of t1 and t2 in one cycle T of the eccentric body 22, it is possible to obtain an arbitrary vibration waveform from a sine waveform to a sawtooth waveform. Moreover, the vibration waveform can be changed not only when the casting is stopped but also at any time during the casting operation.

It should be noted that, during the casting, the casting conditions change frequently, and in particular, the casting speed usually decreases in the initial stage of casting, in the final stage, or at the time of connection between the present casting and the next casting. By giving the change information of the casting speed to the control unit 27, the mold is vibrated with an optimum vibration waveform in association with the change of the casting condition. Further, in the case of the present embodiment, it is desirable that the mold lowering speed be slightly higher than the casting speed of the slab.

In summary, the present invention has the following effects because it adopts the configuration described in the claims.

[Advantage of the Invention] Since the vibration waveform for vibrating the mold is formed in a sawtooth shape, the mold lubricant supplied to the mold can be made to uniformly flow between the mold and the surface of the solidified and shrunk slab. ,
The quality of the surface of the slab can be improved. In particular, since the mold lubricant is evenly flown between the mold and the surface of the slab, heat transfer is evenly performed, and it is possible to prevent the occurrence of vertical cracks on the surface of the slab and to avoid breakout.
Of course, since such a phenomenon occurs due to various factors, it is not possible to uniformly determine which shape of the sawtooth waveform is good, but the optimum value of the sawtooth waveform is obtained by actual operation at the equipment site. Therefore, according to the present invention, since the vibration waveform can be arbitrarily changed during the casting operation, the optimum vibration waveform can be easily obtained by the control.

When obtaining an arbitrary vibration waveform, since a hydraulic motor was selected to drive the eccentric body in rotation, it is possible to easily obtain any anharmonic vibration with large acceleration, and the frequency is the initial value of the continuous casting technology. The impact force can be suppressed to a small level because it is quite large unlike. When we tried to obtain anharmonic vibration by the electric motor, we found that the motor requires a large torque due to its large acceleration, and as a result, the inertia of the motor needs to be further increased. , With a normal electric motor, 1 cycle is 0.
If it is set to 2 seconds, it is impossible to control the ascending stroke to 0.15 seconds and the descending stroke to 0.05 seconds. Therefore, it has been proved that the electric motor cannot be used to drive the rotation of the oscillation eccentric body.

Since the present invention oscillates with an eccentric body, the eccentric body has a long track record as a mechanical oscillation device, so that the oscillation device of the present invention is highly reliable and can be operated by a hydraulic motor. It can be controlled arbitrarily and can be convenient.

Since it is a hydraulic motor, it is much cheaper, has better repair and durability than hydraulic servo cylinders.

[Brief description of drawings]

FIG. 1 is a model diagram showing an embodiment of the present invention, and FIG.
FIG. 3 shows a time-stroke graph in a state in which the number of revolutions is changed by the apparatus shown in FIG. 3, and FIG. 3 shows a time-stroke graph showing a vibration waveform obtained by changing the number of revolutions in FIG. 20 …… hydraulic motor 22 …… eccentric body 23 …… oscillation rod 24 …… detector 27 …… control unit 28 …… servo valve 29 …… hydraulic power source

Claims (1)

[Claims] 1. A continuous casting apparatus in which an end of an oscillation rod connected to a mold is connected to an eccentric body, the eccentric body is rotated to vertically vibrate the mold, and a mold lubricant is added. In the oscillation device described above, a hydraulic motor that rotationally drives the eccentric body, a detector that detects the rotational angle position of the eccentric body, and a control unit that controls the rotation of the hydraulic motor are provided, and the hydraulic motor and the hydraulic power source are provided. A servo valve is provided between the control unit and the rotation angle position information from the detector that detects the rotation angle position of the eccentric body, and the control unit inputs a command according to the rotation angle position to the eccentric body. By outputting a signal to the servo valve,
An oscillation device of a continuous casting machine, wherein the rotational angular velocity of the eccentric body is changed during one cycle of vertical vibration of the mold to give a sawtooth-like vibration waveform to the mold.