JPH0241893A - Flying cutter - Google Patents

Abstract

PURPOSE:To constrain the system to be driven being moved by its own inertia and remarkably reduce the error in the cutting length of a web even in case of the torque output of a driving side being fluctuated by providing a resisting means giving resistance to the system to be driven which includes a transmission mechanism. CONSTITUTION:The resistance set by a setter 13 is applied on a shear driving mechanism 8 by a resisting force setter 13 and brake device 12 during the cutting work of a web 6. The torque control is then executed so as to increase the torque output of a motor 9 by a control device 10 by the part corresponding to this resistance and a positive torque output state is maintained always. Consequently, the chartering between the driving side gear 14 and driven side gear 16 in the speed reducer 11 interposed between the motor 9 and driven gear 16 side is prevented and the accuracy in the cutting length of the web 6 can be increased.

Description

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

[Conventional technology]

In order to cut a web that is continuously transported while it is being transported, a flying shear that cuts the web while moving the shear at the same speed as the web transport speed is used, for example, as described in Japanese Patent Publication No. 61-59878. is used.

FIG. 5 schematically shows an example of a running cutting machine using the above flying shear. The web 30 is continuously transported at a constant speed in the six directions of arrows in the figure.

The transfer length of the web 30 is monitored by the rotation of the length measuring roll 32 that follows 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 in accordance with the transfer length data from the length measuring roll 32, and adjusts the torque output of the motor 34. In addition,
The motor 34 is provided with a motor shaft encoder 36, and the drive of the motor 34 is feedback-controlled by a control circuit 33.

The rotation of the motor 34 is 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 a shear 31 consisting of a pair of upper and lower cutting blades along the transport direction of the web 30 as shown by arrow B, and the shear 31 moves at a speed that is equal to or lower than the web 30.
When the transport speed becomes equal to the transport speed of , the upper and lower cutting blades are engaged with each other, thereby cutting the web 30.

As shown in the above-mentioned publication, the shear drive mechanism 41 is composed of a crank mechanism, etc., and moves the shear 31 and drives the cutting blades into engagement by simply rotating the motor 34 in the forward direction, and also initializes the shear 31. Move back to position. Note that after cutting the web 30, the torque output of the motor 34 is reduced by a signal from the control circuit 33, and the shear 3
1 slowly returns to the initial position to complete one cutting process.

[Problems to be solved by the invention] By the way, in the above-mentioned running cutting machine, the motor 3
The driving force from 4 is transmitted to the shear drive mechanism via a mechanical driving force transmission system represented by a reduction gear 37. However, in a mechanical drive force transmission system, there is mechanical backlash, as seen, for example, in the meshing portions between gears. Such backlash causes backlash between the driving side and the driven side when the torque output on the driving side fluctuates. In the case of the above-mentioned running cutting machine, a problem arises in that the driving force of the motor 34 is transmitted to the shear drive mechanism 41 with a delay.

FIG. 6(A) conceptually shows how the driving force is transmitted in the reducer 37. When the driving side gear 43 rotates due to the driving force from the motor 34, the teeth 43a are Move to the center right. Then, the gear 44a on the driven side meshing with this receives the driving force, and the gear 44 is driven to rotate. However, as described above, since the torque output from the motor 34 is varied by the control circuit 33, the output shaft 4
The driving force appearing at 2 will also fluctuate. When the driving force from the output shaft 42 is reduced, the driven systems after the deceleration m37, such as the shear drive mechanism 41, continue their previous motion due to inertia, as shown in FIG. 6(a). Then, the gear 44 on the driven side moves forward with respect to the gear 43, and after the tooth 44a moves by a distance X, it comes into contact with the back of the tooth 43a and pushes it around. This movement reaches the motor 34 via the deceleration a37, which means that a negative rotational torque is generated in the motor 34 during the period to, as shown in FIG. 3(A).

When such a phenomenon occurs, in order to start the next cutting process, the torque output of the motor 34 is increased to rotate the output shaft 42 at an accelerated rate (sometimes, while the teeth 43a of the gear 43 move by the distance , the driving force is no longer transmitted to the shear drive mechanism 41.

However, the length measuring roller 32 normally supplies the transfer length data to the control circuit 33, and the control circuit 33 adjusts the driving torque of the motor 34 based on this data, so the backlash at the reducer 37 is caused by the web 30. This will cause cutting length errors.

Figure 4 (a) shows an example of actual measurement data of cutting length error,
The solid line represents the cutting length error when the web 30 is cut while the transport speed is increasing, and the broken line represents the cutting length error when the web 30 is cut while the transport speed is decreasing. There is a requirement for inter-travel cutting machines to be introduced into actual production lines to suppress the cutting length error related to the web transfer speed to within 0.25 mm, so the conventional inter-travel cutting machines as mentioned above This requirement could not be met.

′ [Object of the Invention] The present invention has been made to solve the above-mentioned problems, and provides a running cutting machine that can prevent a decrease in cutting length accuracy due to backlash in the mechanical system and is reliable in terms of stability. The purpose is to provide

[Means to solve the problem]

In order to achieve the above object, the present invention includes a flying shear that cuts a web being transported, a shear operating mechanism that operates the flying shear, and a mechanism that mechanically transmits driving force from a drive source to the shear operating mechanism. It consists of a transmission mechanism and a resistance means that applies resistance to a driven system including the transmission mechanism, and is configured to drive the shear operating mechanism against the resistance.

[Operation] Since the resistance means is provided, by appropriately setting the resistance force provided by the resistance means, it is possible to prevent the driven system from moving away from the transmission mechanism due to inertia. Therefore, backlash does not occur due to backlash inherent in the transmission mechanism, making it possible to improve cutting length accuracy.

Ru.

Embodiments of the present invention will be described below with reference to the drawings.

〔Example〕

In FIG. 1, which schematically shows an embodiment of the present invention, transport length data of a web 6 that is transported at a constant speed in the direction of arrow A is output from a length measuring roller 7.

A motor shaft encoder 8 is arranged on the shaft portion of the motor 9,
Outputs the rotation angle data of the motor shaft. The control circuit 10 performs electrical processing based on the transfer length data, rotation angle data, and resistance force data output from the length measuring roll 7, the motor shaft encoder 8, and the resistance force setting device described later, and controls the motor 9.
Controls the torque output from. This realizes acceleration/deceleration rotation of the motor shaft. The torque thus output is used as driving force for the entire mechanical system.

During normal operation, the output shaft 19 is rotated by the torque passed through the reducer 11. The rotation of the output shaft 19 is transmitted to the shear drive mechanism 18. The shear drive mechanism 18 operates the shear 17 using 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 arrow B, and also causes the cutting blades to engage and move in the cutting position.

By continuously operating the shear drive mechanism 18, the shear 17 repeats reciprocating motion and web cutting motion at a constant cycle, and the web 6 is cut into constant lengths.

The brake device 12 includes, for example, a friction brake, 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.

Furthermore, the frictional heat generated in the brake device 12 is removed by a heat radiator 15.
Heat is dissipated by

A resistance corresponding to R in FIG. 3(A) is applied to the shear drive mechanism 18 by the resistance force setting device 13 and the brake device 12. The control circuit 10 performs torque control to increase the torque output of the motor 9 by an amount corresponding to this resistance R. Therefore, even during the period L1 in which the drive load of the shear drive mechanism 18 itself decreases, the motor 9 always maintains the positive torque output state j1M. Note that the magnitude of the resistance R can be appropriately set in consideration of the transport speed of the web 6 and the like when presetting the resistance force setting device 13.

When cutting the web 6 with the above configuration,
Even during the period t1, a load is applied to the driven gear 16 inside the reducer 11 due to the resistance R, and the driven gear 16 rotates in advance of the driving gear 14. and gear 1, as shown in Figure 2.
The teeth 14a of the gear 16 always come into contact with the teeth 16a of the gear 16 from a fixed direction and transmit torque.
a never leaves the tooth 14a. As a result, play due to the meshing of the gears 14 and 16 does not occur, and there is no control delay between the control of the motor shaft and the response of the mechanical system, and it is possible to improve cutting length accuracy.

FIG. 4(A) shows actual measurement data showing the cutting length error when cutting the web 6 as described above.

According to Tore, the cutting length error is 0.25 mm or less regardless of the transport speed, both when cutting the web 6 while increasing the transport speed (solid line) and when cutting while decelerating it (broken line). It can be suppressed to

In the above embodiment, frictional heat is radiated by the radiator 15, but a motor may be used as the brake device and the electric power generated therein may be effectively extracted by applying regenerative braking.

〔Effect of the invention〕

As described above, in the running cutter of the present invention, resistance is always applied to the driven system to prevent negative torque output from being generated on the driving side. Therefore, even if the torque output on the drive side fluctuates, the movement of the driven system due to its own inertia is suppressed, and the responsiveness of the shear drive mechanism deteriorates due to backlash generated within the mechanical 4° drive transmission system. This makes it possible to significantly reduce web cutting length errors.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of a running cutting machine according to the present invention. FIG. 2 is an explanatory diagram of the operation of the embodiment shown in FIG. 1. FIGS. 3A and 3B are waveform diagrams showing motor torque outputs of an embodiment of the present invention and a conventional example, respectively. FIGS. 4(A) and 4(B) are graphs showing actual measured values of web cutting length errors in an embodiment of the present invention and a conventional example, respectively. FIG. 5 is a schematic diagram showing an example of a conventional running cutting machine. FIGS. 6A and 6B are explanatory diagrams showing how backlash occurs in the meshing portion of gears. 6 ・ ・ 7 ・ ・ 8 ・ ・ 9 ・ ・ 10 ・ 12 ・ l 3 ・ 14゜17 ・ Web length measuring roller motor shaft encoder motor control circuit Brake device Resistance force setting device 6... Gearsha rotation direction Fig. 5

Claims (1)

[Claims] (1) A flying shear that cuts the web being transported;
A shear operating mechanism that operates this flying shear,
It consists of a transmission mechanism that mechanically transmits the driving force from the drive source to the shear operating mechanism, and a resistance means that applies resistance to the driven system including this transmission mechanism, and the resistance means applies resistance to the driven system. A running cutting machine characterized by operating a flying shear.