JP2009196315A - Rubber extrusion apparatus and method for manufacturing strip rubber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber extrusion apparatus capable of compatibly attaining stabilization of the extruding quantity and increasing of extruding capacity directly extruding speed of a rubber material. <P>SOLUTION: Two gear pumps 1, 2 are arranged in series, the gear pump 1 located in a downstream side is an extruding machine 6 and the gear pump 2 located in a upstream side is a warming machine 7, a pressure sensor 9 is arranged between the extruding machine 6 and the warming machine 7, and a control means for controlling the rotational speeds of the gear pump 2 constituting the warming machine 7 based on the detecting result of the pressure sensor 9 is arranged in the rubber extrusion apparatus. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rubber extrusion device suitable for use in manufacturing a belt-like rubber having a required cross-sectional shape, which is wound around a core body such as a molding drum or a rigid core to mold a constituent member of a tire, and The present invention relates to a method of manufacturing rubber strips for tire components used, and in particular, proposes a technology that stabilizes the extrusion amount of rubber material, increases the extrusion capability, and enables downsizing of the device. To do.

A conventional rubber extrusion device of this type is described in Patent Document 1.
This is because the discharge port of the gear pump type heat inserter is connected to the intake port of the gear pump type extruder directly or indirectly through a closed pipe, and the rubber material is supplied to the gear pump type heat inserter. A feed roller is arranged on the side, and this extrusion apparatus can make the apparatus itself compact and can obtain excellent energy efficiency.
JP 2007-1235 A

  This invention is a further improvement of the prior art described in Patent Document 1, and further improves the extrusion accuracy by stabilizing the extrusion amount of the rubber material while maintaining the advantages brought about by the prior art. In addition, an object of the present invention is to provide a rubber extrusion device capable of reducing the size and a method for producing a belt-like rubber with higher extrusion ability.

  In addition, the improvement of the extrusion accuracy by stabilizing the extrusion amount of the rubber material here is that the belt-like rubber extruded from the extrusion apparatus and molded at the die opening of the head and given a specific shape is put on various cores. Directly or indirectly through a tire constituent member on the core body, when molding a raw tire, it is possible to achieve high-precision homogenization of the shape, including dimensions, of the rubber band Therefore, it is extremely important in improving uniformity of the raw tire and, in turn, the uniformity of the product tire itself, and removing variations in quality between tires.

By the way, it is possible to improve the extrusion accuracy by stabilizing the extrusion amount of the rubber material by lowering the extrusion speed of the rubber material, but this greatly reduces the productivity of the raw tire. Other problems will arise.
Thus, conventionally, there has been a relationship in which the improvement of the extrusion accuracy by stabilizing the extrusion amount of the rubber material, the extrusion speed, and thus the productivity are mutually contradictory.

  Accordingly, the present invention provides a rubber extrusion device capable of achieving both stabilization of the extrusion amount of a rubber material and extrusion capability, and directly an increase in extrusion speed, and a strip for a tire component using the device. A method for producing rubber is provided.

  The rubber extrusion device according to the present invention can be either an external gear pump or an internal gear pump, and has a plurality of gear pumps arranged in series, and is located on the most downstream side in the moving direction of the rubber material. The extruder and the one or more gear pumps located upstream from the extruder are used as a heating machine that imparts plasticity to the rubber material and provides a boosting effect. A pressure sensor is disposed between the machine and a control means for controlling the rotational speed of the gear pump constituting the heating machine based on the detection result of the pressure sensor.

  When the gear pump is an external gear pump, the gear pump includes a casing and a pair of gears of the same size that are rotated with respect to the casing under mutual engagement. When it is a contact gear pump, it comprises a drive small gear and an internal gear that meshes with the small gear and is eccentric with respect to the small gear.

  In such a rubber extrusion device, preferably, one of the two gear pumps is an extruder, and the other is a hot-watering machine.

  Further, according to the present invention, a method for producing a belt-like rubber is obtained by sequentially passing through each of a heating machine and an extruder including a serially arranged gear pump, and from a die opening of a head provided on the front side of the extruder. A rubber material having a predetermined cross-sectional shape, including dimensions, is continuously extruded at a constant speed, for example, to plasticize the rubber material when manufacturing a rubber band for molding tire components. The pressure of the plasticized rubber material is measured between the heating machine and the extruder, and the rotational speed of the gear pump constituting the heating machine is increased, reduced or reduced according to the measurement result. There is no control over any change.

In this case, it is preferable to supply the rubber material directly to the heating machine without using a feed roller or the like. Preferably, when the measured pressure of the rubber material exceeds the upper limit setting value, When the rotational speed of the gear pump constituting the filling machine is lowered and the measured pressure falls below the lower limit set value, control is performed to increase the rotational speed of the gear pump.
In addition, this speed control is performed so that all the heating machines may be at a constant speed when there are a plurality of heating machines each including a plurality of gear pumps.

  By the way, in the speed control as described above, bubbles are generated in the rubber material extruded from the extruder so as not to generate a negative pressure between the extruder and the heat exchanger. It is necessary to prevent it.

  In the rubber extrusion device according to the present invention, one of a plurality of gear pumps arranged in series is used as an extruder, and the other gear pump is used as a heating machine for plasticizing a rubber material fed to the extruder. The rotational speed of the gear pump of the heating machine is determined based on the pressure of the plasticized rubber material measured by the pressure sensor of the plasticized rubber material measured by the pressure sensor disposed between the extruder and the heating machine. By performing feedback control that is controlled by the control means, while always ensuring the required positive pressure between them, the extrusion amount of the rubber material from the extruder is sufficiently stabilized and the extrusion accuracy is greatly improved. In addition, since high extrusion accuracy can be realized without lowering the operating speed of the extruder, the extrusion ability can be sufficiently increased and the productivity of the tire can be greatly improved.

In addition, here, by controlling the operating speed of the gear pump heat exchanger, the rubber material to be supplied is plasticized by the heat input device, so that the rubber material to be supplied is bitten into the heat input device. In the past, it was necessary to omit the feed roller, which had been required to be disposed upstream of the rubber material in order to properly feed the rubber material to the heating machine. As a result, the structure of the extrusion apparatus can be simplified and the entire apparatus can be miniaturized.
In other words, the feed roller has a role of stabilizing the amount of rubber material supplied to the supply destination, but the heating machine makes the filling of the supplied rubber material more reliable and also has a boosting effect. By controlling the operation speed, the supply amount to the extruder can be stabilized without a feed roller.

  And when the whole extrusion apparatus is reduced in size, a belt-like rubber having a predetermined cross-sectional shape is continuously formed at a constant speed, for example, through a die opening of a head provided on the front side of the extruder. The belt-like rubber may be a rigid core that can be disassembled and assembled, an outer shape corresponding to the inner shape of the product tire, a cylindrical drum, a barrel-shaped bulging form, a core, or the like. 4. Extrusion that is necessary to form a required tire component on the core body CO by directly or indirectly winding on the core body CO as illustrated in FIG. There is an advantage that the occupied space for the three-dimensional motions such as the device E and the head H, the integral turning motion and the up-and-down motion in the horizontal plane can be effectively reduced.

  By the way, such downsizing of the extrusion apparatus is made up by configuring one of the two gear pumps as an extruder and the other as a heating machine, and omits other roller pumps as well as feed rollers. It is more effective when there is.

  In the manufacturing method of the strip rubber according to the present invention, when manufacturing the strip rubber for the tire constituent member through the hot press and the extruder both configured by the gear pump, the plasticizing between the hot press and the extruder is performed. By measuring the pressure of the rubber material and performing feedback control to control the rotation speed of the gear pump that constitutes the heating machine according to the measurement result, the pressure of the rubber material between the heating machine and the extruder Is kept within a predetermined range, the extrusion amount of the rubber material is stable and the extrusion accuracy can be sufficiently increased, and the extrusion speed does not need to be reduced to improve the extrusion accuracy. Together, high-precision extrusion can be performed at a high speed, which can greatly improve the extrusion capacity and thus the tire productivity.

  In this method, when the rubber material is supplied directly to the heating machine without using a feed roller or the like, the entire structure of the extrusion device is simplified and the device is sufficiently downsized. This can be realized, and the occupied space required for the three-dimensional movement of the extrusion apparatus as described above can be sufficiently reduced.

  And also in this method, when the measured pressure of the plasticized rubber material exceeds the upper limit set value, the rotation speed of the gear pump hot-water machine is reduced while the measured pressure falls below the lower limit set value. In addition, when performing control to increase the rotational speed of the heat exchanger, the pressure of the plasticized rubber material is kept within a predetermined range under the proper selection of the upper limit value and the lower limit value and without the possibility of chattering. It is possible to reliably maintain the extrusion amount of the rubber material as a stable uniform value, to sufficiently increase the extrusion accuracy, and to increase the extrusion ability as expected.

FIG. 1 is a view showing an embodiment of a rubber extrusion device according to the present invention in a cross section along a central axis.
In the figure, reference numerals 1 and 2 denote gear pumps arranged in series and adjacent to each other. These gear pumps are arranged in a common housing 3 and mesh with each other. Each pair of gears 4a, 4b and 5a, 5b.

  Here, the gears 4a, 4b and 5a, 5b of the gear pumps 1, 2 both having the same dimensions are supported on a line segment parallel to the central axis of the gear pumps 1, 2. The gears 4a and 5a and 4b and 5b do not mesh with each other even though they are located close to each other.

  Also, here, of the two gear pumps 1 and 2 arranged in this way, one gear pump 1 located on the downstream side in the movement direction F of the rubber material is the extruder 6 and the other gear pump 2 is Let it be a heating machine 7.

  And the pressure which measures the center pressure of the rubber material which was put into the chamber 8 divided by those both 6 and 7 between the extruder 6 and the heating machine 7, and was plasticized by heating. A sensor 9 is provided, and control means (not shown) is provided for controlling the rotational speed of the gear pump 2 constituting the heating machine 7 based on the detection result of the pressure sensor 9.

Here, the speed control by this control means, when the measured pressure of the rubber material exceeds the upper limit value of the preset allowable pressure range, while reducing the rotational speed of the gear pump hot water filling 7 as required, When the measured pressure falls below the lower limit value of the allowable pressure range, it is preferable to increase the rotational speed of the gear pump heat exchanger 7 as required.
It should be noted here that both the reduction in the rotational speed as required and the increase as required are selected in relation to the allowable pressure range, the capability of the gear pump 2, and the like.

  In the extrusion apparatus configured as described above, the supplied unvulcanized rubber material G is supplied in the direction indicated by the arrows of the gears 5a and 5b of the gear pump 2 of the heat exchanger 7 that mesh with each other. Under the rotational motion at a controlled speed, heat is generated and heated by friction between the wall surface of the housing 3 and the gears 5a and 5b, shearing deformation of the rubber material itself, and the like into the chamber 8. In the chamber 8 as well, it will be sufficiently plasticized by undergoing friction and shear deformation with the gears 5a, 5b.

  Here, when the heating machine 7 performs such a heating operation on the rubber material G, since the rotation speed of the heating machine 7 is appropriately controlled, as described above, like a feed roller. Further, without providing a special supply means for the rubber material G, the rubber material G is bitten between the housing 3 and the gears 5a and 5b as expected, and into the chamber 8. It can be sent properly.

  Then, the plasticized rubber material G maintained at a pressure within the allowable range in the chamber 8 is then continued to the respective gears 4a and 4b of the extruder 6 that are rotated at a required speed as indicated by arrows in the figure. Is extruded toward the head 10 attached to the front end side of the extrusion apparatus, and is molded into a predetermined shape including a predetermined size and extruded from the opening of the die 11 of the head 10 to form a tire. It is considered as a band-like rubber for members.

In this case, since the plasticized rubber material G in the chamber 8 is reliably maintained at a pressure within a predetermined range by controlling the rotational speed of the heating device 7, the rubber material G is supplied to the extruder 6, and hence the extruder. Since a predetermined amount is stably extruded from the apparatus, high extrusion accuracy can be realized.
In addition, here, the pressure in the chamber 8 of the rubber material G can be surely kept within a predetermined range regardless of the rotational speed of the heating device 6, so that the extrusion capacity of the rubber material G is as expected. Can be increased.

  By the way, the rubber strip manufactured in this way is a raw tire that is molded by being wound directly or indirectly on any of the cores described above under the rotational motion of the core. This is used for molding of a required tire component.

  In addition, the mutual center point of the allowable range of the center pressure of the rubber material G in the cavity 8 and the rotational speed of the gear pump 2 constituting the heating machine 7 are indicated by a line segment A in FIG. In addition to being linearly controlled, it can also be controlled to have a curved shape as indicated by line segment B.

Example 1 in which an extrusion apparatus according to the present invention shown in FIG. 1 is used and the rotational speed of the gear pump 2 is controlled as shown by a line segment A in FIG. 2 based on the rubber material pressure measured by the pressure sensor 9. 1 and Comparative Example 1 and 2 in which the speed control of the gear pump 2 was not performed even though the extrusion device shown in FIG. 1 was used, the variation in the volume of the rubber material extruded from the pressing machine was measured. The result was obtained.
In Table 1, as shown in FIG. 3, the variation in the volume of the rubber material of the conventional example 1 in which the screw extruder EX is used as a heating machine instead of the gear pump 2 of the apparatus according to the present invention is also shown. Also shown.
Also in this conventional example 1, the rotational speed control of the screw extruder EX is not performed.

According to the results shown in Table 1, while the amount of extrusion was increased in Example 1 and the variation was kept small enough, in Comparative Example 1, the speed control of the heating machine 7 was performed even under the same amount of extrusion. It can be seen that the variation is considerably large because no operation was performed.
On the other hand, in Comparative Example 2 in which the amount of extrusion was reduced, it can be seen that the variation can be reduced to about half of that in Comparative Example 1.

  However, in the conventional example 1 in which the screw extruder EX is a hot-water extruder, when the pressure of the plasticized rubber material between the hot-water extruder and the extruder increases, the rubber material flows backward to the screw extruder EX side. It is clear that the variation becomes large even when the extrusion amount is kept low due to the change in the viscoelastic characteristics of the rubber material.

It is a figure showing an embodiment of a device concerning this invention in a section which meets a central axis. It is a basic line graph which shows the example of control of the rotational speed of a heating machine based on rubber material pressure. It is sectional drawing which shows the apparatus used in the prior art example 1. It is a basic line top view which shows the example of winding of strip | belt-shaped rubber | gum on a core.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Gear pump 3 Housing 4a, 4b, 5a, 5b Gear 6 Extruder 7 Heater 8 Chamber 9 Pressure sensor 10 Head 11 Die F Movement direction of rubber material G Rubber material

Claims (5)

  A plurality of gear pumps are arranged in series, and the one gear pump located on the most downstream side is used as an extruder, and one or more gear pumps located on the upstream side from this extruder are used as heat-filling machines. A rubber extruding apparatus comprising a pressure sensor provided between the machine and the heating machine, and a control means for controlling the rotational speed of the gear pump constituting the heating machine based on the detection result of the pressure sensor.   The rubber extrusion device according to claim 1, wherein one of the two gear pumps is an extruder and the other is a hot-watering machine. For tire components by sequentially extruding a rubber material having a required cross-sectional shape from a head provided on the front side of the extruder through each of a heating machine and an extruder including a gear pump arranged in series. In producing the belt rubber of
A method for producing a belt-like rubber that measures the pressure of a rubber material between a heating machine and an extruder and controls the rotational speed of a gear pump constituting the heating machine according to the measurement result.   The manufacturing method according to claim 3, wherein the rubber material is directly supplied to the hot water machine.   When the measured pressure of the rubber material exceeds the upper limit set value, the rotational speed of the gear pump that constitutes the heating machine is reduced, and when the measured pressure falls below the lower limit set value, the rotational speed of the gear pump is decreased. The manufacturing method of Claim 3 or 4 which performs control to increase.

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