JPS60232306A - Positioning control device for pinch roll conveying steel pipe - Google Patents

Abstract

PURPOSE:To enhance the degree of accuracy in the positioning of a pinch roller with the use of a squirrel cage motor, by providing such an arrangement that an instruction for stopping the motor at the next time is compensated in accordance with a difference between a previous setting position and an actual stopping position. CONSTITUTION:The elevated position of a pinch roller is detected by a position detector 4, and is stored in a memory 9 after being converted by a converter 5. A desired stopping position is set by means of a setting unit 6. When a positioning starting button is depressed, the normal or reverse direction of a motor is determined by means of elevating direction discriminators 7, 8, and either one of contactors F, R in a reversible electromagnet relay 1 is energized. A comparator 10 computes a difference between the desired value set on the setting unit 6 and the detector 4, and a relay for issuing a motor stopping instruction STP is energized to stop the motor 2 when the difference becomes coincedent with a braking distance. With this arrangement, the positioning of the pinch roller may be made with a high degree of accuracy by use of a normal-insertion system squirrel cage motor.

Description

[Detailed description of the invention] The present invention relates to a pinch roll positioning control device.

Generally, the pinch rolls that convey the W4 pipe must be positioned at a position that matches the pipe diameter every time the pipe diameter of the steel pipe changes.

Conventional positioning devices of this type are driven by a direct-in type machining mower, stopped by an electromagnetic brake, and the operator operates a control switch and performs positioning by looking at the position scale. Ta. In order to perform this positioning automatically, good positioning accuracy cannot be obtained mainly due to changes in the load torque and changes in the braking torque of the electromagnetic brake.
Required an expensive variable speed electric motor. In addition, if you try to use a direct insertion method, in order to ensure accuracy,
There was a restriction that the positioning speed could not be increased.

In view of the above-mentioned drawbacks of the conventional example, the present invention provides a pinch roll positioning control device that can provide good positioning accuracy by using a conventional inexpensive direct-in type cage carving machine as a drive device. With the goal.

The present invention provides a pinch roll positioning control device that includes a pinch roll that conveys a steel pipe, an electric motor that raises and lowers the pinch roll, an electromagnetic brake, and a position detector that detects the raising and lowering position of the pinch roll. The difference between the set position and the actual stop position is stored, and a stop command is output to the motor at the next positioning to correct the stop position.

In a pinch roll positioning device, the current position is detected by a position detector, and the braking distance (distance t from when braking starts until it comes to a complete stop) is determined before the position where the pinch roll is to be stopped.
In anticipation of a), a command to stop the motor is output,
An electromagnetic brake is used to stop the vehicle at a predetermined position. The braking force is the sum of the load torque and the braking torque of the electromagnetic brake, and the control distance changes depending on the change in the load torque or the braking torque of the electromagnetic brake, which deteriorates accuracy. However, the load torque of the y-lowering device of the pinch roll is due to mechanical losses such as the reduction gear and the ball screw, and it can be considered that the load torque does not change by 8 to 1, but changes gradually. Furthermore, the braking force of the electromagnetic brake changes gradually due to wear.

The present invention has been made with attention to this point, and if there is a deviation between the set position and the actual stopping position after performing the positioning operation - times, for example, if the set position is moved too far and the stop is made, the braking force The actual braking force may have decreased, or the actual braking force may have been smaller than the expected braking force.If the next time positioning is made, correct the expected braking distance to a smaller value to maintain highly accurate positioning. It becomes possible.

In addition, when replenishing grease or adjusting the gap of the electromagnetic brake during periodic repairs, conventional adjustments were made by trial and error, but according to the present invention, if the positioning operation is performed one or two times, The braking distance is corrected in response to the changed braking force, eliminating the need for conventional adjustments.

The present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is a sequence diagram for explaining the operation of FIG. 1.

In FIG. 1, l is a reversible electromagnetic contactor that switches the rotation direction of the electric motor 2, 2 is an electric motor that raises and lowers a pinch roll that conveys a steel pipe (not shown), 3 is an electromagnetic brake that brakes and stops the electric motor 2, 4 is a position detector that detects the vertical position of the pinch roll (not shown), and 5 is a converter that converts the vertical position information of the pinch roll detected by the position detector 4 into a signal.

6 is a setting device for setting the desired vertical position of the pinch roll, 7.8 is an M descending direction (upward and downward direction) discriminator for determining the y-descending direction of the pinch roll, and 9 is a device used for the previous positioning. A memory device that stores the difference between the set value and the actual value, IO is a comparator that corrects the braking distance of the electric motor 2 based on the output from the memory device 9, and +1 (Fig. 2) is a positioning start push button. .

” To explain the operation of the embodiment having the configuration described in item 2, the vertical position of the pinch roll (not shown) is detected by the position detector 4,
A converter 5 converts the signal. Set the setting value of the desired Gino descent position in the setting device 6, and press the positioning start push button 1 in Fig. 2.
When 1 is pressed, the signal from the lifting direction discriminator 7 or 8 will cause the
The forward or reverse direction of the motor is determined, and F or R of the reversible '+i, l1t1 contactor l is excited. When the difference between the set value and the current value detected by the position detector 4 matches the braking distance, the comparator 10 excites the relay for the motor stop command STP, and the motor 2 is stopped.

In the above embodiment, the case where the car is driven by a direct-in type cage carving motive machine is described, but if the frequency of positioning is high,
Wound motors are sometimes used, and it is clear that similar control methods can be applied in this case as well.

As explained below, according to the present invention, the drive is performed by a simple direct-on type motor without using an expensive variable speed motor, and highly accurate positioning can be performed automatically. Readjustment can be done easily.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is a block diagram of an embodiment of the present invention.
FIG. 3 is a sequence diagram for explaining the operation of the illustrated embodiment. 1-m=reversible electromagnetic contactor 2--1 electric motor 3--1 electromagnetic brake 4-m-position detector 5--1 signal converter 6--, immersion device 7--one-way discriminator 8-- - One-way discriminator 9 - One storage device 10 - One comparator

Claims (1)

[Claims] In a pinch roll positioning device that includes a pinch roll that conveys a steel pipe, an electric motor that raises and lowers the pinch roll, an electromagnetic brake, and a position detector that detects the y-lowering position of the pinch roll, A pinch roll positioning control device comprising: means for storing a difference from an actual stop position; and means for correcting the stop position by outputting a stop F command to the electric motor during the next positioning.