JP2013043350A - Method and control device for extrusion of unvulcanized rubber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and control device for extrusion of unvulcanized rubber, capable of stabilizing the shape or weight of the unvulcanized rubber early in the initial stage after restarting the extrusion to thereby prevent the generation of defective products.SOLUTION: There is provided the method of extruding the unvulcanized rubber by which the unvulcanized rubber extruded into a certain shape by an extruder is placed on a transport conveyer and transported. In the method, when the extrusion is restarted after the extruder filled with the unvulcanized rubber is stopped, the unvulcanized rubber is transported for a predetermined time or by a predetermined length at a certain transport speed predetermined so that the unvulcanized rubber keeps a certain shape. The extrusion control device for the unvulcanized rubber includes a control means for performing the above control.

Description

  The present invention relates to an unvulcanized rubber extrusion method and an extrusion control device for molding an extruded product such as a sidewall.

  In the case of producing an extruded product such as a sidewall, unvulcanized rubber is extruded into a fixed shape by an extruder, a preformer, a die plate, and the like, and then conveyed by a conveyor.

  In the case of rubber replacement, preformer replacement, die plate replacement, etc., the extruder is stopped while the unvulcanized rubber is filled, and then the extrusion is restarted.

  When restarting extrusion, an extrusion method that starts at the reference speed, which is the normal transport speed, and then checks the shape and partial weight of the extruded product and feeds it back to the transport speed of the transport conveyor is performed. However, when the width of the extruded product is narrow or the weight is light, the conveyance speed is controlled to be slower than the reference speed, which is a normal conveyance speed.

  As can be seen from the above, in the initial stage after resuming extrusion by feeding back the operator's check result, the product is pushed out at the reference speed, resulting in a defective product due to the initial stage product greatly deviating from the predetermined shape and weight. There was a problem to do.

  In view of this, a method has been proposed in which the extrusion speed is detected by a roller in contact with the extruded rubber immediately after extrusion, and the conveyor speed is controlled by the extrusion speed (for example, Patent Document 1).

  However, at the initial stage of resuming extrusion, the temperature of the discharged rubber and die swell (shrinking method) are different from the case of extrusion in a steady state. There was a problem that it was difficult to get.

  In addition, since the extrudate has a large change in the conveyance speed to bring it close to the set width, and there is a time lag from a change in the conveyance speed to a width change, it is difficult to stabilize at an early stage, and there is a problem of hunting. It was happening. Moreover, since the width change is large when the extrusion is resumed, the tire quality (FV) is adversely affected, and defective products are generated due to the width defect.

JP 2006-1198 A

  In view of the above problems, the present invention provides an unvulcanized rubber extrusion method capable of stabilizing the shape and weight of unvulcanized rubber at an early stage and suppressing the occurrence of defective products in the initial stage of restarting extrusion. It is another object of the present invention to provide an extrusion control device.

  The present inventor has found that the above problems can be solved by the inventions described in the following claims, and has completed the present invention. Hereinafter, each claim will be described.

The invention described in claim 1
A method for extruding unvulcanized rubber in which a fixed shape unvulcanized rubber extruded by an extruder is placed on a conveyor and conveyed.
When resuming extrusion after the extruder filled with the unvulcanized rubber has stopped,
A method for extruding unvulcanized rubber, characterized in that the unvulcanized rubber is conveyed for a predetermined time or a predetermined length at a predetermined conveyance speed so that the unvulcanized rubber maintains the constant shape. is there.

The invention described in claim 2
2. The method for extruding unvulcanized rubber according to claim 1, wherein the predetermined constant conveying speed is determined according to a length of a stop time of the extruder.

The invention according to claim 3
The stop time is classified into a plurality of ranks according to the length of the stop time of the extruder, and the predetermined constant conveyance speed and the predetermined time or the predetermined length are set for each rank. The method for extruding unvulcanized rubber according to claim 2, wherein:

The invention according to claim 4
The stop time is classified into a plurality of ranks in the range of 30 seconds to 2 hours. In each rank, the predetermined constant conveyance speed is within a range of 10 to 30 m, and the predetermined constant conveyance speed is normal conveyance. The method for extruding unvulcanized rubber according to any one of claims 1 to 3, wherein the method is set within a range of 50% or more and less than 100% of a reference speed which is a speed. .

The invention described in claim 5
An unvulcanized rubber extrusion control device that carries unvulcanized rubber of a certain shape extruded by an extruder on a conveyor,
When restarting the extrusion after the extruder filled with the unvulcanized rubber is stopped, the unvulcanized rubber is kept at the constant shape at a predetermined conveyance speed for a predetermined time or a predetermined length. An unvulcanized rubber extrusion control device comprising control means for conveying the unvulcanized rubber.

The invention described in claim 6
6. The unvulcanized rubber extrusion control device according to claim 5, further comprising control means for determining the predetermined constant conveyance speed in accordance with a length of a stop time of the extruder. It is.

The invention described in claim 7
The stop time is classified into a plurality of ranks according to the length of the stop time of the extruder, and the predetermined constant conveyance speed and the predetermined time or the predetermined length are set for each rank. The unvulcanized rubber extrusion control device according to claim 5 or 6, further comprising a control means.

The invention according to claim 8 provides:
The stop time is classified into a plurality of ranks in the range of 30 seconds to 2 hours. In each rank, the predetermined constant conveyance speed is within a range of 10 to 30 m, and the predetermined constant conveyance speed is normal conveyance. The unvulcanized rubber according to any one of claims 5 to 7, further comprising control means each set within a range of 50% or more and less than 100% of a reference speed which is a speed. Extrusion control device.

  According to the present invention, there is provided an unvulcanized rubber extrusion method and an extrusion control device capable of stabilizing the shape and weight of unvulcanized rubber at an early stage and suppressing the occurrence of defective products at the initial stage of restarting extrusion. can do.

It is a figure which shows the display screen of the display apparatus with which the extrusion control apparatus of the unvulcanized rubber which concerns on this invention is equipped. It is a figure which shows transition of the width change of each extrusion molding of an Example and a comparative example.

  Hereinafter, based on an embodiment, the present invention will be specifically described with reference to the drawings.

  The present invention is characterized in that the conveyance speed of unvulcanized rubber at the time of resumption is reduced to a predetermined speed based on the stop time of the extruder and conveyed for a predetermined time or a predetermined length. This is because, in the initial stage of extrusion, the amount of unvulcanized rubber discharged from the extruder is lower than the steady state, and the degree of the reduction depends on the stop time before the extrusion is restarted.

  That is, in the initial stage after resumption, the speed immediately after extrusion is not fed back and controlled as in the prior art, but is transported for a predetermined time or a predetermined length at an appropriate speed previously known from the length of the stop time. This stabilizes the shape and weight of the unvulcanized rubber at an early stage and suppresses the occurrence of defective products.

  Specifically, the conveyance speed, the predetermined time, and the predetermined length in the above are determined according to a prior experiment, an empirical rule, etc., the stop time of the extruder created for each material of the unvulcanized rubber, the conveyance speed, and the predetermined length. Basic data is created in advance for the correlation between the time and the predetermined length and the moldability, and is set based on the basic data.

  And according to the experiment of the present inventor, there is no difference in the appropriate conveyance speed due to a slight stop time, and even if the stop time is divided into certain sections and the speed and time (length) according to the sections are set. It was found that there was no practical problem.

  For this reason, by ranking the stop times within a practically unaffected range, the control contents can be simplified without complicating, and workability at the production site can be improved.

  As a specific example, when the stop time is in a range of 30 seconds to 2 hours, the stop time is classified into a plurality of ranks, and a predetermined length is set to an appropriate value within a range of 10 to 30 m in each rank. Then, by setting a predetermined constant conveyance speed to an appropriate value within a range of 50% or more and less than 100% of the reference speed, which is a normal conveyance speed, appropriate control can be performed.

(Specific embodiment)
Hereinafter, specific embodiments will be described.

  The basic data and stop time ranking data obtained as described above are stored in an arithmetic processing device such as a PC and linked with the extrusion control device, so that the appropriate control described above can be performed more easily. .

  For example, by first selecting the composition of the unvulcanized rubber to be extruded from the display device, the corresponding control content is displayed on the display device from the stored data.

  FIG. 1 shows an example of control contents displayed on the display device. In FIG. 1, a reference conveyance speed corresponding to the selected composition is displayed on the set value display section 6 a of the conveyance speed display section 6. And the level (division) of the target equipment stop time is specifically displayed on the stop time level display unit 3 (3a to 3c), and each control speed ratio display unit 4 (4a to 4d) The reduction rate of the conveyance speed corresponding to the division is displayed.

  Next, by automatically counting the equipment stop time on the stop time display section 5, a level corresponding to the stop time from the stop time level display section 3 is selected, and the transport speed is displayed according to the rate of reduction of the applicable transport speed. The actual speed display section 6b of the section 6 shows a specific transport speed to be controlled after the restart. At the same time, the control length display unit 2 displays the length of the conveyor that performs the deceleration extrusion.

  By performing extrusion molding after resumption based on the displayed conveyance speed and length, the shape and weight of the unvulcanized rubber are stabilized at an early stage and the occurrence of defective products is suppressed in the initial stage of extrusion resumption. be able to. Note that after completion of the deceleration extrusion, extrusion molding is performed at the above-described reference conveyance speed.

  Thus, by following the present embodiment, it is possible to control the extrusion after the stop and restart very easily.

  Hereinafter, examples and comparative examples will be described.

1. Extruding unvulcanized rubber
(Example)
In this example, the machine in which the side wall size: AS160T (side wall total width: 160 mm, width tolerance: ± 3 mm) was pushed out at the reference speed (16.4 m / min) of the conveyor is less than 2 minutes (exactly Is an example of measuring the variation in the width of the extruded rubber when it is stopped and then restarted.

  At this time, the conveyance conveyor speed was extruded at 98% of the reference speed from the restart until the length of 20 m was extruded, and then the extrusion was performed at the reference speed to obtain an extruded rubber having a total of 40 m.

  The length of 20 m and the speed of 98% of the reference speed are values set in advance as appropriate values based on experiments.

(Comparative example)
For comparison, after stopping the equipment for a little less than 2 minutes (1 minute 52 seconds to be precise), the extrusion was resumed with the reference speed (16.4 m / min), and a 40 m extruded rubber was obtained.

  About the extrusion rubber obtained by the Example and the comparative example, the width | variety was measured for every 1 m. FIG. 2 shows the measurement results. In FIG. 2, the vertical axis indicates the difference (mm) between the control width (total side wall width: 160 mm) and the extrusion width at each extrusion length, and the horizontal axis indicates the measurement position, that is, the extrusion length after restarting extrusion. (M) is shown. Also, ● is the measurement result of the example, ■ is the measurement result of the comparative example,

  From FIG. 2, although the stop time of the extruder is almost the same as less than 2 minutes, the variation (R) in the extrusion width was 3.9 mm in the comparative example, whereas in the example, it was 2.9 mm. As a result, it was found that the number was decreased, and the effect of the control in this example could be confirmed.

  Next, 30 lots of the examples and comparative examples were extruded in the same manner as described above, and R (average) and σ (standard deviation) of variation were obtained. The results are shown in Table 1.

  From Table 1, even when the number of lots was increased, the variation and its standard deviation were smaller in the example than in the comparative example, and the effect of the above control could be confirmed.

  And when the tire of the size P235 / 65R18 04T ELS N5 D was manufactured using the rubber | gum of the Example extruded to the said size, FV (St / B) is the same as the rubber | gum obtained by the comparative example (St / B). 4.8 / 3.3 to 3.3 / month (using rubber), and by using the rubber obtained in the example, it can be improved by 31%, and the above control is favorable for improving FV. It was confirmed that it had an effect.

2 Control length display section 3, 3a, 3b, 3c Stop time level display section 4, 4a, 4b, 4c, 4d Control speed ratio display section 5 Stop time display section 6 Transport speed display section 6a Set value display section 6b Actual speed Display section

Claims (8)

A method for extruding unvulcanized rubber in which a fixed shape unvulcanized rubber extruded by an extruder is placed on a conveyor and conveyed.
When resuming extrusion after the extruder filled with the unvulcanized rubber has stopped,
A method for extruding unvulcanized rubber, characterized in that the unvulcanized rubber is conveyed for a predetermined time or a predetermined length at a predetermined conveyance speed so that the unvulcanized rubber maintains the certain shape.   2. The method for extruding unvulcanized rubber according to claim 1, wherein the predetermined constant conveying speed is determined in accordance with a length of a stop time of the extruder.   The stop time is classified into a plurality of ranks according to the length of the stop time of the extruder, and the predetermined constant conveyance speed and the predetermined time or the predetermined length are set for each rank. The method for extruding unvulcanized rubber according to claim 2, wherein:   The stop time is classified into a plurality of ranks in the range of 30 seconds to 2 hours. In each rank, the predetermined constant conveyance speed is within a range of 10 to 30 m, and the predetermined constant conveyance speed is normal conveyance. The method for extruding unvulcanized rubber according to any one of claims 1 to 3, wherein the method is set within a range of 50% or more and less than 100% of a reference speed which is a speed. An unvulcanized rubber extrusion control device that carries unvulcanized rubber of a certain shape extruded by an extruder on a conveyor,
When restarting the extrusion after the extruder filled with the unvulcanized rubber is stopped, the unvulcanized rubber is kept at the constant shape at a predetermined conveyance speed for a predetermined time or a predetermined length. An unvulcanized rubber extrusion control device comprising control means for conveying the unvulcanized rubber.   6. The unvulcanized rubber extrusion control device according to claim 5, further comprising control means for determining the predetermined constant conveyance speed in accordance with a length of a stop time of the extruder. .   The stop time is classified into a plurality of ranks according to the length of the stop time of the extruder, and the predetermined constant conveyance speed and the predetermined time or the predetermined length are set for each rank. The unvulcanized rubber extrusion control device according to claim 5 or 6, further comprising: a control means.   The stop time is classified into a plurality of ranks in the range of 30 seconds to 2 hours. In each rank, the predetermined constant conveyance speed is within a range of 10 to 30 m, and the predetermined constant conveyance speed is normal conveyance. The unvulcanized rubber according to any one of claims 5 to 7, further comprising control means each set within a range of 50% or more and less than 100% of a reference speed which is a speed. Extrusion control device.

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