JPH026043A - Method for controlling speed in molten metal supplying apparatus - Google Patents

Abstract

PURPOSE:To improve productivity of molten metal supplying apparatus by fixing low speed driving control position of a ladle even in case the molten metal surface changes at the time of reciprocatively shifting the ladle at interval between a crucible and a molten metal supplying hole and controlling the other reciprocative way at high speed drive. CONSTITUTION:The molten metal 18 in a crucible 17 is shifted from (a) position to (d) position through (b), (c) positions with the ladle 21 and supplied into the molten metal supplying hole 15. The supplied molten metal is cast into a die 12 in a die casting machine 11. In there, the surface of the molten metal 18 is detected with a molten metal surface sensor 22 and a control unit 28, etc., controls so as to always make the low speed driving control position (height H) constant and the time for descending the ladle at low speed drive constant. Further, the other go-to way (a c) and come-back way (d b) are controlled at high speed drive so as to make the change of the necessary time little. By this method, the productivity of the molten metal supplying apparatus can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a control device for the reciprocating speed of a ladle in a ladle hot water supply system, and more particularly to a method for controlling the speed at which the ladle approaches a hot water level on its return journey.

[Conventional technology 1 An example of the prior art will be explained based on the drawings.

In FIG. 3, II shows a part of the die casting machine, 12 is a mold device, 13 is an injection sleeve, 14
is the injection plunger.

15 is an opening provided in the injection sleeve and is a hot water supply port.

d shows the state in which hot water supply is completed by rotating the ladle,
16 is the supplied molten metal.

17 is a crucible of a molten metal holding furnace, and 18 is a molten metal. 19
2 is a multi-joint mechanism water heater, and 20 is its arm, to which a ladle 21 is attached. Reference numeral 22 denotes a hot water level sensor attached to the arm 20, and is an electrode that outputs an energization signal when the sensor comes into contact with the hot water level. The state in which the hot water level sensor 22 is in contact with the hot water surface is the state in which the ladle is fully pumping molten metal.

23 is the water heater 1 of the articulated ladle reciprocating mechanism;
9, and is driven by a variable speed electric motor 24.

In such a configuration, the dog 29 provided on the drive shaft 23 of the water heater 19 of the articulated ladle reciprocating mechanism and the corresponding limit switch 30 operate the ladle 2.
The deceleration of the drop near the hot water level on the return trip of step 1 and low-speed drive control were performed.

[Problems to be Solved by the Invention] However, when the level of the molten metal falls due to pumping up the molten metal several times, the relationship between the limit switch 30 and the dog 29 does not change, so the height between the ladle 21 and the molten metal level decreases. It changes.

Therefore, since the speed at which the ladle 21 descends to and approaches the hot water level is low, the time required until the ladle 21 is immersed below the hot water level and the hot water level sensor 22 is activated increases. Therefore, there is a drawback that the cycle time of the hot water supply cycle increases and productivity decreases.

SUMMARY OF THE INVENTION An object of the present invention is to provide a speed control method in which the cycle time of a hot water supply cycle hardly changes even if the hot water level changes.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a pulse generator attached to the shaft of a drive system of a variable speed electric motor that reciprocates the ladle between the crucible and the hot water supply port; A reversible preset counter that adds and subtracts in response to the A-phase pulse and B-phase pulse of the pulse generator, and a state in which the ladle is pumping up molten metal.

In response to the operation of the hot water level sensor attached to the arm supporting the ladle and the reversible preset counter to detect the hot water level, the variable speed electric motor operates only on the return path of the ladle. When the ladle is on the return path and descends onto the molten metal surface and approaches the molten metal surface, the descending speed is reduced.

The count (direction) of the reversible preset counter corresponding to the height (H) above the hot water surface of the ladle is input in advance, and when the hot water supply cycle is started and the hot water level sensor moves away from the hot water surface, The reversible preset counter starts counting, and when the ladle finishes dispensing hot water and is switched to the return trip, the reversible preset counter is decremented, and when the pre-entered count value is reached, the reversible preset counter starts counting. - In response to the operation of the counter, the control device operates and decelerates the variable speed electric motor,
In the speed control method, the ladle is lowered close to the hot water level by low speed driving, and when the hot water level sensor detects the hot water level, the reversible preset counter is reset.

[Function] In the above configuration, when the ladle is on the return path and descends onto and approaches the molten metal surface, its descending speed is reduced. The reversible preset corresponds to the height H of the ladle above the hot water surface.
Count value of the counter.

By simply setting it in advance, even if the molten metal level drops due to pumping, the molten metal level sensor will detect the molten metal level and reset the reversible preset counter, so the count value will always be the same as the preset count value. The variable speed electric motor can be decelerated and driven at a low speed to keep the height H above the hot water level constant. Therefore, the time required for the ladle to descend from the height H above the molten metal surface and to be immersed in the molten metal is kept constant. Therefore, it acts to keep the cycle time of the hot water supply cycle approximately constant.

[Example] The following two inventions will be explained based on the drawings of the example.
In FIG. 1, 11 shows a part of the die-casting machine, 12 is a mold device, 13 is an injection sleeve, and 14 is a die-casting machine.
is the injection plunger.

15 is an opening provided in the injection sleeve and is a hot water supply port.

d shows the state in which hot water supply is completed by rotating the ladle,
16 is the supplied molten metal.

17 is a crucible of a molten metal holding furnace, and 18 is a molten metal. 19
2 is a multi-joint mechanism water heater, and 20 is its arm, to which a ladle 21 is attached. Reference numeral 22 denotes a hot water level sensor attached to the arm 20, and is an electrode that outputs an energization signal when the sensor comes into contact with the hot water level. A state in which the hot water level sensor 22 is in contact with the hot water surface is a state in which the ladle is drawing up molten metal.

Reference numeral 23 is a drive shaft of the multi-jointed ladle reciprocating mechanism 19, which is driven by a variable speed electric motor 24.

25 is a pulse generator that generates A-phase pulses and B-phase pulses; the A-phase and B-phase have a phase difference; when the pulse generator rotates normally, the A-phase precedes the A-B-phase pulse; When it is reversed, the B phase takes the lead and sends out the B-A phase pulse.

26 is a reversible preset counter that receives the pulses from the pulse generator, and on the forward path of the ladle, the pulse generator 25
generates the A-B phase pulse, the reversible preset counter is incremented, and on the return trip of the ladle, that is, in the step of returning from position d to position a, the B-A phase pulse is generated. The reversible preset counter is decremented. A curve E shown by a dotted line in FIG. 1 is the trajectory of the ladle on its outward and return journeys. When the ladle 21 returns to the position b of the reversible preset counter and descends onto the molten metal surface and approaches it, the height of the ladle of the reversible preset counter 26 corresponding to the height I], assuming that its height is H, is Assuming the number of pulse counts on the outward path, input the count value in advance.

Then, when the hot water supply cycle is started, the ladle draws up the molten metal in state a, advances on its outward path, and stops in state C.
Next, the ladle 21 is rotated to the state d to complete hot water supply, and the flow is switched to the return path, and the speed changeable electric motor 24 is reversed. Since the ladle 21 is empty, it returns to position b of the ladle at high speed.

At position b, when the reversible preset counter is decremented to a preset value input in advance, the reversible preset counter operates, receives the control output 27, and changes the speed of the variable speed electric motor 24. The control device 28 is actuated to decelerate and drive at low speed.

Then, the ladle 21 is lowered by low speed drive, and the hot water level sensor 2 is
2 descends until it touches the molten metal surface and stops.

Then, when the hot water level sensor 22 is activated, the reversible preset counter 26 is reset and the count becomes zero.

The hot water supply cycle is now complete.

When the next hot water supply cycle starts again, the hot water supply cycle continues as described above, but since the set value of the reversible preset counter 26 is always counted from the hot water level, the ladle 21 is not in the state of b. The height H of the drop above the molten metal surface is always constant.

FIG. 2 is a flowchart showing the speed control described above.

The speed control program can be input into a sequencer equipped with a microcomputer according to a flowchart, and the program can be executed.

The speed control program is started, and a 0th water supply cycle is started in which a count corresponding to H is preset, and the water supply cycle continues until the speed control is executed and a hot water supply cycle stop signal is input. When the hot water supply cycle stop signal is input, the speed control program ends.

[Effects of the Invention] As described above, even if the molten metal surface changes, the low-speed drive control position (height H) of the ladle is always constant, the time for descending with the low-speed drive is constant, and other , that is, a −'
c, the return trip d→b is driven at high speed, so there is little change in the required time. Therefore, the cycle time of the hot water supply cycle is almost constant.

Therefore, productivity can be improved.

[Brief explanation of the drawing]

FIG. 1 is a side view of an embodiment of the present invention, FIG. 2 is a flowchart of speed control of a hot water supply cycle of the present invention, and FIG. 3 is a side view of a conventional hot water supply apparatus. 11--Die casting machine, 12--Mold device. 15...Hot water supply 0.18--Molten metal, 19...-Hot water supply device. 21... Ladle, 22... Hot water level sensor, 23...-
Drive shaft 24--variable speed electric motor, 25--pulse generator. 26... Reversible preset counter, 28... Control device, 29-... Dota, 30... Limit switch.

Claims (1)

[Claims] A pulse generator attached to the shaft of the drive system of a variable-speed electric motor that moves the ladle back and forth between the crucible and the hot water supply port, and a reversible preset that receives and adds and subtracts phase A and B pulses from the pulse generator. - A counter, a molten metal level sensor attached to an arm supporting the ladle, which detects the molten metal level when the ladle is pumping up molten metal in the crucible, and an operation at a set value of the reversible preset counter. and a control device that operates only on the return path of the ladle to decelerate and drive the variable speed electric motor at a low speed, so that the ladle is lowered onto the molten metal surface in the crucible during the return path. A count value of the reversible preset counter corresponding to the height (H) of the ladle above the hot water surface, which reduces the descending speed when approaching the ladle, is input in advance, and the hot water supply cycle is started. When the surface sensor moves away from the hot water surface, the reversible preset
The counter starts adding up, the ladle completes hot water supply,
When switched to the return path, the reversible counter is decremented;
When the pre-input count value is reached, the control device is actuated in response to the operation of the reversible preset counter to decelerate the variable speed electric motor and lower the ladle close to the hot water level at a low speed. . A speed control method in a water heater, characterized in that when the hot water level sensor detects the hot water level, the reversible preset counter is reset.