JPS6042140B2 - Web delivery tension control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the feeding tension of a web, and more particularly, to a method for controlling web feeding tension, and more particularly, to prevent various manufacturing failures caused by slack or tension in the web that occurs when starting or stopping a web feeding motor. The present invention relates to a method for controlling the tension of a web that can be easily and inexpensively manufactured.

The term "web" used in the present invention refers to a flexible elongated object, such as a plastic film, paper, or thin metal plate, which usually has a thickness of several micrometers to several tens of micrometers. In the manufacturing process, the above-mentioned web is generally wound into a roll and then sent out from a delivery roll shaft and subjected to predetermined processing, for example, for the purpose of cutting, perforating, printing, etc. be.

By the way, conventionally when sending out the web in this way,
For example, a tension detection means such as a differential transformer or a tension pickup connected to the dancer roll is provided in the web conveyance system, while a braking means such as a DC motor or powder brake is connected to the delivery roll shaft to detect the tension. It has been common practice to control the web delivery tension by electrically or mechanically controlling the braking means using an output signal from the means.

However, when such a tension control method is used, it is essential to provide a tension detection means in the web running system, which increases the size of the device. The disadvantages are that the paper mechanism is complicated and the control device is expensive.

What is also important is that when such webs are fed out, manufacturing failures often occur due to web breakage or overruns when the apparatus is started or stopped.

It is well known that these failures become more pronounced the faster the web travels and the faster the work is processed. Therefore, in order to prevent these failures, other driving means that can follow the web feed speed are generally used when starting up the equipment, and braking means such as a fluke or clutch are used when stopping the equipment, and when using a DC motor, Braking means based on regenerative control have been used, but as a result, this has had the disadvantage of increasing the manufacturing cost of the device as a whole, as described above.

The present invention eliminates the above-mentioned drawbacks of conventional web tension control methods, enables high-speed web feeding without causing any hindrance to the web when starting and stopping the device, and provides a simple and inexpensive web system configuration. The present invention aims to provide a delivery tension control method.

An object of the present invention is to provide a method for controlling the delivery tension of a web sent out from a delivery roll shaft by a web feed roll, in which a DC motor is connected to the delivery roll shaft, and a DC motor is connected to the delivery roll shaft. To absorb the load energy of the delivery roll shaft when the feed roll is stopped by applying a torque corresponding to pretension to the delivery roll shaft by applying rotation in the opposite direction to the delivery direction. This is achieved by applying a braking torque of 1 to the delivery roll shaft via the DC motor for a certain period of time, and then returning the braking torque to a torque corresponding to the pretension.

The details will be explained below based on examples.

FIG. 1 is a schematic diagram of an apparatus according to one embodiment of the present invention, and FIG. 2 is a diagram showing the delivery torque characteristics of this embodiment.

In FIG. 1, 1r is a web roll wound around a core 2, 1 is a web sent out from the web roll 1r, and 3
is the delivery roll shaft equipped with core 2, 4 is the DC motor,
5 is a controller, 6 is a feed roll, and 7 is a feed motor that drives the feed roll 6.

In normal web feeding work, the web 1 is fed to feed rolls 6, 6 which are rotated by the feed motor 7.
The web roll 1r is fed out in the direction of the arrow a while being held between the web rolls 1r and 1r.If the work is temporarily interrupted in the middle of the work, such as during an abnormality or a break, the running of the web 1 is stopped by stopping the drive of the feed motor 7. In this web feeding method, the feeding roll shaft 3 is always energized in the web feeding direction (arrow a A rotational force is applied in the opposite direction (direction of arrow b) to the web 1, and a certain pretension (stall tension) is applied to the web 1 fed out from the web roll 1r.

In other words, this pretension force means that the web 1 being fed out from the web roll 1r is stretched between the web roll 1r and the feed roll 6.
This refers to the tension that will not loosen between the rollers or be wound up on the delivery roll shaft 3 side. Next, the delivery torque characteristics of the web 1 sent out by this web delivery method will be explained based on FIG. 2.

In the figure, M1 indicates the point in time when the feed motor 7 is started to start the feeding operation, M2 indicates the point in time when the feed motor 7 is stopped and the operation is interrupted, and point P.

, Pl, . . . , P6, respectively, shows a torque characteristic diagram of the DC motor acting on the delivery roll shaft 3 during work interruption and during work. Straight line P until time M1 when work starts. , Pl,
Constant torque T. is applied to the delivery roll shaft 3. This torque T. is the torque corresponding to the pretension, and its optimum value is determined experimentally, taking into consideration the web feeding speed required at the start of feeding the web 1, and the mechanical properties of the web 1 itself. . Next, when the feed motor 7 is started at time M1, the torque is T.

to T1, and thereafter the predetermined torque curves P2, P3
is gradually decreased along the line until the corner point is reached when the next operation is interrupted. Here, the torque T1 is inevitably determined from the tension to be applied to the web 1 and the winding diameter of the web roll 1r, and the torque curves P2 and P3 are experimentally determined in advance from various tension control methods such as constant torque or constant tension. It is set based on the optimal characteristic curve determined by When the feed motor 7 is stopped at time M2, the torque is increased from T2 to T3, and after a certain period of time t has passed from the time of stop, the torque is increased to the first T.

will be returned to. Here, the torque T3 is a braking torque for absorbing the load energy acting on the delivery roll shaft 3. If this value is too large, it will give a strong impact to the web 1, and if it is too small, it will cause the web 1 to become slack. is usually determined by experimenting with an intermediate value between these two values.

Further, the time t is necessarily determined from the torque T3 and the magnitude of the load energy acting on the delivery roll shaft 3.

In normal work, the conditions such as the type of web 1, the winding diameter of web roll 1r, and the web feed speed are all constant, so the torque characteristic value mentioned above is determined by the controller 5 before the start of work. can be programmed. Furthermore, when a factor change occurs, the purpose is achieved by changing the set value to a predetermined value determined separately experimentally. As detailed above, in this web feeding method, the braking torque T3 is applied in the opposite direction to the web feeding direction for a certain period of time in order to absorb the load energy acting on the feeding roll shaft 3 when the feed motor 7 is stopped. After applying t, the braking torque T3 is changed to a torque T corresponding to the pretensioning force.

Therefore, when the feed motor 7 starts and stops, the web 1 does not become abnormally slack or tense, and the web 1 is always under tension higher than a certain value, so it can be cut. It is possible to start up to high speed in a short time without any trouble. Regarding the control of such tension, tension pickup as in the conventional method,
Alternatively, there is no need to provide a tension detection means such as a dancer roll, and everything can be programmed via the controller 5, so the conventionally complicated automatic web threading mechanism becomes simple and the device can be manufactured compactly and at low cost. There are advantages that can be achieved. Although the content of the present invention has been described above based on one embodiment, the present invention is not necessarily limited to this embodiment, and various changes can be made without departing from the gist of the claims. It goes without saying that there is.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram showing a delivery characteristic diagram of this embodiment. DESCRIPTION OF SYMBOLS 1... Web, 1r... Web roll, 2... Core, 3... Delivery roll axis, 4... DC motor, 5
...Controller, 6...Feed roll, 7...Feed motor.

Claims (1)

[Claims] 1. A method for controlling the delivery tension of a web sent out from a delivery roll shaft by a web feed roll, in which a DC motor is connected to the delivery roll shaft, and a direct current motor is connected to the delivery roll in a direction opposite to the web delivery direction. A torque corresponding to pretension is applied to the delivery roll shaft by rotation, and when the feed roll is stopped, a braking torque for absorbing the load energy of the delivery roll shaft is applied to a certain level. A method for controlling a web delivery tension, characterized in that the braking torque is applied to the delivery roll shaft via the DC motor for a certain amount of time, and then the braking torque is returned to a torque corresponding to the pretension.