JPS60106623A - Alarming device of shear pin cutting - Google Patents

Abstract

PURPOSE:To prevent cutting of a shear pin between a roll and an electric motor in advance by detecting load torque of a straightening roll of a rolling mill by current and number of rotation of an electric motor for roll driving and reporting overtorque by an alarming device such as a buzzer or an indication lamp. CONSTITUTION:The straightening roll 2 and its driving electric motor 1 of the steel plate rolling mill are connected by an intermediate shaft 3 having an interposed shear pin 4. Current of the electric motor 1 is measured by a shunt 7. Load torque of the roller 2 is calculated by an overtorque detector circuit 8. This is compared with rated torque for using shear pin, and when larger than the rated torque, it is judged as overtorque and detected. However, as acceleration torque and deceleration torque become necessary when the motor 1 accelerates and decelerates, rotation speed of the electric motor 1 is detected by a detector 6 and subtracted from above-mentioned comparison value. When it is judged as overtorque, an alarm is given by a buzzer 9, an indicator etc., and cutting of the shear pin 4 due to overtorque is prevented in advance.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a shearing pin of a straightening machine or a rolling mill in a steel plate factory, and in particular, a method for firing the front shaft of the shearing pin in advance before the shearing pin is cut. 0 [Prior Art] Figure 1 shows a conventional example of mechanical connection and organization of shear pins.
In the figure, (1) is an electric motor that drives the straightening roll (2), (8) is an intermediate shaft that connects the electric motor (1) and the straightening roll (2), and (4I is a mechanically protective film for the straightening machine). It's a sharpie.

Next, the operation will be explained. Power is transmitted by the motor (1) to the roller (2) via the intermediate shaft (8), but if the load on the roller (2) side becomes abnormally large and overtorque occurs, the intermediate shaft (8) must be protected. A shear pin (4) is used to cut the shaft to prevent damage to the intermediate shaft. Conventional mechanical shear pin cutting 11. l [Since the detection device is configured as r4 as above, the shear pin (4)
It is necessary to always go to the site and visually check the condition of the
4) Since it is practically difficult to visually predict and judge the state immediately before cutting, 1. Normally, the shear pin (4) is used after cutting.
I had to replace it with a new one.

[Summary of the invention]

This invention was made to eliminate the drawbacks of the conventional ones as described above. Overtorque on the load side is electrically detected from the motor's main circuit current and rotation speed, and the overtorque is detected immediately before the shear pin breaks. The object of the present invention is to provide a shear pin cutting alarm device capable of outputting an alarm.

[Embodiments of the invention]

An embodiment of the present invention will be described below.

In Figure 2, (6) is a thyristor device for supplying DC power to the DC motor (1), (6) is a digital counterfeit meter directly connected to the DC motor (1), and (γ) is the DC motor ( 1), a current shunt that detects the main circuit current;
This is an overtorque detection device that detects overtorque by inputting iF, and when overtorque occurs, the warning buzzer (9) sounds and the alarm indicator lights up before the shear pin (4) is disconnected. .

That is, in the configuration shown in FIG. 2, overtorque is detected by utilizing the fact that the load torque of the roller (2) can be calculated from the rotational speed of the DC motor (1) and the main circuit current. (4) sends out IV alarm power before being disconnected.

The rated torque for use of the shear pin (4) is Tg-s (kg-
IO) (Overload resistance iX2%) Roller load torque to Tg
, 6M, the relationship Tg·s ) 'l'g*M holds true. As shown in Fig. 3, the roller load torque Tg-M is calculated based on the main circuit current detected from the shunt (1), and the rated torque Tg-M for use with a shear pin is compared. When Tge M becomes larger than 8, overtorque and -I'lJ~1 are detected. However, as shown in Figure 4, acceleration torque or deceleration torque is required when the electric motor (1) accelerates or decelerates, so this acceleration/deceleration torque must be excluded from the above comparison when accelerating or decelerating the electric motor (1). . Execute it using the following method.

In other words, the overtorque detection device (8) determines the timing of start and stop of operation and the operating speed (rotation speed of the electric motor) at that time based on the operation command REF to the thyristor device (5).
Enter. For acceleration torque, the period from the start of acceleration to the designated speed (designated rotation speed) is excluded from the comparison, and for deceleration torque, the period from the start of deceleration (stop command) to the time of stopping is excluded from the comparison. In addition, in Fig. 4, the space between is the acceleration torque, (
6) is the deceleration torque and m) is the overtorque. In the above embodiments, the case of a straightening machine in a steel plate mill or a shear pin in a rolling mill has been described, but the same effect can be achieved with a shear pin in a rolling mill or a conveyor line in a hot rolling mill or a blooming mill.

〔Effect of the invention〕

As described above, according to the present invention, there is no need to manually inspect the shearing pin, and it is also possible to grasp the number of times (conditions) of overtorque occurring on the shearing pin and the machine side, which can occur due to shearing pin cutting. It is possible to prevent accidents that may occur.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the configuration of conventional equipment, Fig. 2 is a block diagram showing an embodiment of the present invention, Fig. 3 is a flowchart for determining overtorque, and Fig. 4 is a diagram showing acceleration/deceleration torque and overtorque. This is a graph showing the relationship. (1) Electric motor (2) Roller (8) Intermediate shaft (4) Shear pin (6) Thyristor device (6) Rotation speed i1 (7) Φ shunt RRF... Speed command 2) Acceleration torque (8)) Deceleration torque
-... Overtorque Note that the same reference numerals in the drawings indicate the same or equivalent parts. Agent Masuo Oiwa Figure 1 Figure 4 11 Gate, f 2 ('21 Figure 3 Commissioner of the Japan Patent Office 1, Indication of the case Japanese Patent Application No. 58-215340 2, Title of invention: Sharpin cutting alarm device 3 , Person making the amendment 5. Column for detailed explanation of the invention in the specification to be amended. 6. rTg-3 (floor-m) (overloaded on both sides) on page 4, lines 4-5 of the specification to be amended. - x 2%) Roller load torque"
Tg-3 (ri-m), roller load torque" is corrected. More L

Claims (1)

[Claims] In addition to installing a rotation speed detection needle and a current shunt to detect the main circuit current on the rolling mill drive motor, the load torque excluding torque during acceleration and deceleration is calculated and compared with the normal overload capacity of the machine. A shear pin cutting υ characterized by being provided with an overtorque detection device that sends out a static shaft output in the event of overtorque, and preventing the shear pin provided for keeping the mechanical axis between the electric motor and the straightening roll from being cut. Axis device 0