JPH0747273B2 - Cutting machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a running cutting machine, and more particularly to a running cutting machine improved to eliminate play in a mechanical system.

[Conventional technology]

In order to cut a continuously conveyed web in a transfer state, for example, as described in Japanese Patent Publication No. 61-59878, a flying shear that performs cutting while moving the shear at the same speed as the web transfer speed. Is used.

FIG. 5 schematically shows an example of a cutting machine for running using the flying shear. The web 30 is continuously transported at a constant speed in the direction of arrow A in the figure. The transfer length of the web 30 is monitored by the rotation of the length measuring roll 32 following the transfer of the web 30, and the transfer length data is input to the control circuit 33. The control circuit 33 controls the drive of the motor 34 according to the transfer length data from the length measuring roll 32, and adjusts the torque output of the motor 34. A motor shaft encoder 36 is provided in the motor 34, and the drive of the motor 34 is feedback-controlled by the control circuit 33.

The rotation of the motor 34 is speed-controlled by the speed reducer 37 and then transmitted to the output shaft 42 and then to the shear drive mechanism 41. The shear drive mechanism 41 moves the shear 31 including a pair of upper and lower cutting blades to the arrow B.
As described above, the web 30 is moved along the transfer direction, and when the moving speed of the shear 31 becomes equal to the transfer speed of the web 30, the upper and lower cutting blades are engaged with each other, thereby cutting the web 30.

The shear drive mechanism 41 is composed of a crank mechanism and the like as disclosed in the above-mentioned publication, and the forward rotation of the motor 34 alone drives the movement of the shear 31 and the meshing drive of the cutting blades. Move back to the position. After cutting the web 30, the torque output of the motor 34 is controlled by the control circuit 33.
The shear 31 is slowly returned to the initial position, and the single cutting process is completed.

[Problems to be solved by the invention]

By the way, in the above-mentioned cutting machine, the motor 34
Is transmitted to the shear drive mechanism via a mechanical drive force transmission system represented by the speed reducer 37. However, in the mechanical driving force transmission system, there is mechanical backlash, for example, seen in the meshing portion between gears. Such backlash causes backlash between the driving side and the driven side when the torque output on the driving side fluctuates. Then, in the case of the above-described cross cutting machine, there arises a problem that the driving force of the motor 34 is transmitted to the shear drive mechanism 41 with a delay.

FIG. 6 (a) conceptually shows a state where the driving force is transmitted in the speed reducer 37, and the gear 43 on the driving side is the motor.
When rotated by the driving force from 34, the tooth 43a moves to the right in the figure. Then, the driven gear 44a meshing with this receives the driving force, and the gear 44 is driven to rotate. However, as described above, the torque output from the motor 34 is controlled by the control circuit.
Since it is changed by 33, the driving force appearing on the output shaft 42 also changes. Then, when the driving force from the output shaft 42 is reduced, the driven system after the speed reducer 37, such as the shear drive mechanism 41, continues its motion until then due to inertia, and is shown in FIG. 6 (a). Thus, the gear 44 on the driven side advances with respect to the gear 43, and after the tooth 44a has moved by the distance X, it comes into contact with the back of the tooth 43a and pushes it around. This motion reaches the motor 34 via the speed reducer 37, and as shown in FIG. 3A, it means that a negative rotational torque is generated in the motor 34 during the period t ₀ .

When such a phenomenon occurs, when the torque output of the motor 34 is increased to accelerate and rotate the output shaft 42 in order to start the next cutting process, while the teeth 43a of the gear 43 move by the distance X, The driving force is not transmitted to the shear drive mechanism 41. However, since the length measuring roller 32 normally supplies the transfer length data to the control circuit 33, and the control circuit 33 adjusts the drive torque of the motor 34 based on this, the backlash in the speed reducer 37 causes the backlash of the web 30. It causes a cutting length error.

FIG. 4 (a) shows an example of the measured data of the cutting length error,
The solid line represents the cutting length error when cutting is performed in the process of increasing the transfer speed of the web 30, and the broken line represents the cutting length error when cutting is performed in the process of decreasing the transfer speed. Since the running cutting machine to be introduced into the actual production line needs to keep the cutting length error within 0.25 mm regardless of the web transfer speed, the above-mentioned running cutting machines have It was impossible to satisfy the demand.

[Object of the Invention]

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a cross-cutting machine that can prevent a decrease in cutting length accuracy due to looseness of a mechanical system and is also reliable in terms of stability. And

[Means for Solving the Problems]

In order to achieve the above object, the present invention mechanically transmits a flying shear that cuts a web being transferred, a shear operating mechanism that operates the flying shear, and a driving force from a drive source to the shear operating mechanism. The transmission mechanism and resistance means for giving a resistance to a driven system including the transmission mechanism are configured to drive the shear operating mechanism against the resistance.

[Action]

Since the resistance means is provided, it is possible to prevent the driven system from moving away from the transmission mechanism due to inertia by appropriately setting the resistance force provided by the resistance means. Therefore, backlash does not occur due to backlash in the transmission mechanism, and the cutting length accuracy can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

〔Example〕

In FIG. 1 schematically showing an embodiment of the present invention, the transfer length data of the web 6 transferred at a constant speed in the direction of arrow A is output from the length measuring roller 7. The motor shaft encoder 8 is arranged on the shaft portion of the motor 9 and outputs the rotation angle data of the motor shaft. The control circuit 10 performs electrical processing based on the transfer length data, the rotation angle data, and the resistance force data output from the length measuring roll 7, the motor shaft encoder 8 and the resistance force setting device described later, and the torque from the motor 9 is applied. Control output. This realizes acceleration / deceleration rotation of the motor shaft.
The torque thus output is used as the driving force for the entire mechanical system.

During normal operation, the output shaft is driven by the torque passed through the speed reducer 11.
19 rotates. The rotation of the output shaft 19 is transmitted to the shear drive mechanism 18. The shear drive mechanism 18 operates the shear 17 by a built-in crank mechanism. That is, the shear drive mechanism 18
Causes the shear 17 to reciprocate from the initial position to the cutting position as shown by an arrow B, and causes the cutting blade to engage with each other at the cutting position. Then, by continuously operating the shear drive mechanism 18, the shear 17
Repeats a reciprocating motion and a web cutting motion at a constant cycle, and the web 6 is cut into constant lengths.

The brake device 12 is composed of, for example, a friction brake or the like, and supplies a constant resistance force according to a preset value to the resistance force setting device 13 to the shear drive mechanism 18, that is, the driven system. Also,
The friction heat generated in the brake device 12 is radiated by the radiator 15.

A resistance equivalent to R in FIG. 3A is applied to the shear drive mechanism 18 by the resistance setting device 13 and the brake device 12. The control circuit 10 controls the torque so as to increase the torque output of the motor 9 by an amount corresponding to the resistance R. Therefore, even during the period t ₁ when the drive load of the shear drive mechanism 18 itself decreases, the motor 9 always maintains the positive torque output state. The magnitude of the resistance R can be appropriately set in consideration of the transfer speed of the web 6 when the resistance setting device 13 is preset.

When the cutting work of the web 6 is performed with the above configuration,
Even during the period t ₁ , the driven side gear 16 inside the speed reducer 11 is loaded by the resistance R, and the drive side gear 16 is loaded.
The gear 16 on the driven side does not rotate ahead of the gear 14. As shown in FIG. 2, the teeth 14a of the gear 14 always contact the teeth 16a of the gear 16 from a certain direction to transmit torque, and the teeth 16a do not separate from the teeth 14a. . As a result, backlash due to the meshing of the gears 14 and 16 does not occur, there is no control delay between the control of the motor shaft and the response of the mechanical system, and the cutting length accuracy can be improved.

FIG. 4A is actual measurement data showing a cutting length error when the web 6 is cut as described above. According to this
Whether the web 6 is cut while increasing the transfer speed (solid line) or cut while decelerating (broken line), the cutting length error can be suppressed to 0.25 mm or less regardless of the transfer speed.

In the above-described embodiment, the friction heat is radiated by the radiator 15, but a motor may be used as the braking device and the electric power generated therein may be effectively taken out by applying regenerative braking.

〔The invention's effect〕

As described above, in the cross-cutting machine of the present invention, the driven system is always provided with resistance so that negative torque output is not generated on the drive side. Therefore, even if the torque output on the drive side fluctuates, the driven system is suppressed from moving due to its own inertia, and the responsiveness of the shear drive mechanism deteriorates due to the backlash that occurs in the mechanical drive transmission system. Is eliminated, and the error in the cutting length of the web can be greatly reduced.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the cross cutting machine according to the present invention. FIG. 2 is an operation explanatory view of the embodiment shown in FIG. 3 (A) and 3 (A) are waveform charts showing motor torque outputs of an embodiment of the present invention and a conventional example, respectively. FIGS. 4A and 4B are graphs showing measured values of the cutting length error of the web in the embodiment of the present invention and the conventional example, respectively. FIG. 5 is a schematic view showing an example of a conventional cross-cutting machine. FIGS. 6A and 6B are explanatory views showing how backlash occurs in the gear meshing portion. 6 …… Web 7 …… Measuring roller 8 …… Motor shaft encoder 9 …… Motor 10 …… Control circuit 12 …… Brake device 13 …… Resistance setting device 14,16 …… Gear 17 …… Shear

Claims (1)

[Claims] 1. A flying shear that cuts a web being transferred, a shear operating mechanism that operates this flying shear, a transmission mechanism that mechanically transmits a driving force from a drive source to the shear operating mechanism, and this transmission. A running-disconnecting machine, comprising: a resistance means for giving a resistance to a driven system including a mechanism, wherein the flying shear is operated while the resistance is applied to the driven system by the resistance means.