JP7238420B2 - RUBBER STRIP MANUFACTURING APPARATUS AND MANUFACTURING METHOD - Google Patents

Description

TECHNICAL FIELD The present invention relates to a rubber strip manufacturing apparatus and manufacturing method capable of stably manufacturing a rubber strip.

As one of tire forming methods, a method is known in which a tire component having a desired cross-sectional shape is directly formed on a forming drum by spirally winding a ribbon-like rubber strip on the forming drum. Patent Document 1 below proposes a rubber strip manufacturing apparatus that can be suitably used in the tire forming method.

The proposed manufacturing apparatus comprises an extruder for preforming and extruding input rubber and a pair of calender rolls for pressing and forming the extruded rubber into a rubber strip.

JP 2014-054804 A

On the other hand, in the tire forming method, it is desirable to further reduce the width and thickness of the rubber strip in order to improve the forming accuracy of the tire constituent members. For this purpose, the width and thickness of the molding opening of the die in the extruder must be made small.

However, if the width and thickness of the molding opening of the die are simply set to be small, the shape of the rubber will change rapidly inside the die, resulting in a large amount of shrinkage after extrusion. As a result, problems such as deformation of the formed tire component over time or breakage of the rubber strip within the tire component occur.

In order to prevent this, as shown in FIG. 4(a), it is also necessary to lengthen the rubber flow path a1 by lengthening the nose of the die a to moderate the shape change of the rubber inside the die. becomes.

However, when the die a has a long nose, the distance L between the die a and the calender roll b decreases, as shown in FIG. 4(b). As a result, when the manufacturing apparatus is stopped, lumps g1 of rubber g tend to be generated between the die a and the calender rolls b. The occurrence of the lump g1 is caused by the fact that the rubber in the extruder is discharged from the die a for a while due to residual stress after stopping the manufacturing apparatus.

Then, when the manufacturing apparatus is restarted, the mass g1 cannot pass between the calender rolls b, causing a new problem that the rubber strip G is broken. Breakage of the rubber strip G can cause a significant drop in productivity.

Therefore, the present invention provides a rubber strip manufacturing apparatus capable of suppressing the generation of lumps of rubber between a die and a calender roll even when the die has a long nose, and capable of stably manufacturing a rubber strip. The challenge is to provide a method.

A first invention is an apparatus for manufacturing a ribbon-shaped rubber strip,
an extruder with a die for extruding unvulcanized rubber;
a calendering device disposed on the downstream side of the extruder in the rubber extruding direction and having a calendering roll that presses the rubber extruded from the die to form a ribbon-shaped rubber strip;
a gap defining portion for changing the gap between the die and the calender rolls.

In the rubber strip manufacturing apparatus according to the present invention, the interval defining portion includes a connecting member that connects the calendar device and the extruder,
It is preferable that at least one end side of the connecting member includes an elongated hole extending in the rubber extrusion direction and a first fixture fixed to one of the calendar device and the extruder through the elongated hole. .

In the rubber strip manufacturing apparatus according to the present invention, the gap defining unit includes an actuator that moves one of the calendering device and the extruder relative to the other of the calendering device and the extruder in the rubber extruding direction. is preferred.

In the rubber strip manufacturing apparatus according to the present invention, it is preferable that the spacing regulation section can change the spacing within a range of 10 to 50 mm.

A second invention is a method for manufacturing a ribbon-shaped rubber strip,
extruding unvulcanized rubber from an extruder equipped with a die;
a step of pressing the rubber extruded from the die to form a ribbon-shaped rubber strip with a calender roll disposed on the downstream side of the extruder in the rubber extruding direction;
changing the distance between the die and the calender roll based on the state of the rubber extruded from the die.

The first invention, as described above, includes a gap regulating section for changing the gap between the die of the extruder and the calender rolls.

Therefore, even when a long-nose die is used, it is possible to maintain an appropriate gap between the die and the calendar roll. As a result, when the production apparatus is stopped, it is possible to suppress the generation of lumps caused by the rubber being discharged from the die due to the residual stress in the extruder. In addition, it is possible to suppress the breakage of the rubber strip that occurs when the manufacturing apparatus is restarted due to the lumps, and it is possible to stably manufacture the rubber strip.

Since the second invention includes the step of changing the gap between the die and the calender rolls, it is possible to keep the gap properly. As a result, the same effects as those of the first invention can be obtained.

1 is a sectional view showing an embodiment of a rubber strip manufacturing apparatus of the present invention; FIG. FIG. 2 is an exploded perspective view showing an exploded main portion thereof; FIG. 4 is a cross-sectional view showing the action and effect of the present invention; (a) is a cross-sectional view of a long-nose die, and (b) is a cross-sectional view for explaining problems when using a long-nose die.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail.
As shown in FIG. 1, a rubber strip manufacturing apparatus 1 (hereinafter sometimes simply referred to as "manufacturing apparatus 1") of the present embodiment includes an extruder 2 and a calender device 4 having a pair of calender rolls 3. , and the interval defining portion 5 . In this example, the manufacturing apparatus 1 is arranged in a raw tire manufacturing line and manufactures a ribbon-like unvulcanized rubber strip G for forming a tire component such as a tread rubber.

The extruder 2 includes an extruder body 6 , a gear pump 7 and a die 8 in this example.

The extruder body 6 includes a cylinder 6a and a screw shaft 6b. The cylinder 6a has a substantially cylindrical shape, and a hopper (not shown) for charging rubber is provided on the upstream side thereof. A discharge port 6c for pushing out the rubber g is opened at the downstream end of the cylinder 6a. The screw shaft 6b is rotatably housed in the cylinder 6a and driven by a motor to knead the rubber g from the hopper and push it out toward the discharge port 6c.

The gear pump 7 includes a casing 7a, a rubber chamber 7b, and a pair of extrusion gears 7c, 7c. The casing 7a is connected to the extruder main body 6 on the discharge port 6c side. A rubber chamber 7b is formed inside the casing 7a.

The pushing gears 7c, 7c are arranged in a rubber chamber 7b so as to mesh with each other. The extrusion gears 7c, 7c are motor-driven to feed the rubber g from the extruder main body 6 to the die 8 side quantitatively.

As shown in FIG. 3, the die 8 includes a flange portion 8a replaceably attached to the wall surface on the downstream side of the gear pump 7, and a nose portion 8b projecting downstream from the flange portion 8a. Further, in the die 8, a rubber channel 9 for preforming the rubber g extruded from the extrusion port 7d (shown in FIG. 1) of the gear pump 7 is arranged. The rubber channel 9 includes a forming port 9a that opens at the downstream end of the nose portion 8b, and a channel portion 9b that extends upstream from the forming port 9a while increasing the channel cross-sectional area.

In this example, the upstream end of the flow path portion 9b is formed in substantially the same shape as the extrusion port 7d. On the other hand, the molding opening 9a has a shape close to the cross-sectional shape of the rubber strip G. As shown in FIG. Therefore, by lengthening the nose portion 8b (long nose), the shape change of the rubber g inside the die 9 becomes gentle, and the amount of shrinkage of the rubber g after extrusion can be reduced. Therefore, in order to reduce the amount of shrinkage, it is necessary to use a die 8 in which the length of the nose portion 8b is set according to the shape and size of the molding opening 9a.

The calendering device 4 is arranged downstream of the extruder 2 in the rubber extruding direction, and presses the rubber g extruded from the die 8 to form a ribbon-like rubber strip G. As shown in FIG.

As shown in FIG. 2, the calender device 4 includes a pair of vertically arranged calender rolls 3, a frame 10 that rotatably supports the pair of calender rolls 3, and at least one of the pair of calender rolls 3. and driving means 11 such as a motor for rotational driving.

In this example, the upper calender roll 3 is supported by the frame 10 via the bearing box 12 so as to be able to move up and down. In this example, the frame 10 has a rectangular box shape in which upper and lower ends of parallel side plate portions 10a are connected by an upper plate portion 10b and a bottom plate portion 10c, respectively. A pair of calender rolls 3 are horizontally supported between the side plate portions 10a, 10a. The frame 10 may be, for example, a framework in which frame members are combined in a rectangular shape.

The gap defining portion 5 is provided to change the gap L between the die 8 and the calender rolls 3, as shown in FIG. Strictly speaking, the distance L means the distance between the reference line X passing through each axis of the calender rolls 3 and 3 and the tip of the die 8 .

Here, when the manufacturing apparatus 1 is stopped, the rubber g in the extruder 2 is discharged from the die a for a while due to the residual stress after the stop. At this time, if the interval L is long, as shown in FIG. 3, the rubber g that is discharged after stopping is absorbed in the area Y of the interval L only by deforming, for example, into a wave shape. However, when the interval L is short, as shown in FIG. 4(b), the deformed parts adhere to each other to generate lumps g1. This lump g1 induces breakage of the rubber strip G when the manufacturing apparatus 1 is restarted.

Therefore, in the present invention, the spacing L is changed by the spacing regulating section 5, thereby suppressing the generation of the clump g1. If the interval L is less than 10 mm, it becomes difficult to suppress the generation of lumps g1. Conversely, if it exceeds 50 mm, the meandering of the rubber g in the width direction becomes large within the region Y, and the quality of the rubber strip G tends to deteriorate. Therefore, it is preferable that the interval defining portion 5 can change the interval L within the range of 10 to 50 mm.

As shown in FIGS. 1 and 2, the interval defining portion 5 includes a connecting member 15 that connects the calender device 4 and the extruder 2 in this example. In addition, the space defining portion 5 includes a long hole 16 extending in the rubber extrusion direction and a first fixture 17 passing through the long hole 16 at least on one end side of the connecting member 15 . A first fixture 17 is fixed to one of the calendar device 4 and the extruder 2 . Therefore, the space defining portion 5 of this example can change the space L by the length of the elongated hole 16, and can connect the calender device 4 and the extruder 2 in the changed state.

In this example, the space defining portion 5 includes a connector 18 having two parallel connecting members 15 spaced apart in the width direction.

In this example, the connecting member 18 comprises a base portion 19 attached to the frame 10 of the calendar device 4 and two connecting members 15 extending from the base portion 19 in the rubber extrusion direction. The base portion 19 straddles between the side plate portions 10a, 10a of the frame 10, and both ends of the base portion 19 are attached to the side plate portions 10a via second fixtures 20 such as bolts.

The other end of each connecting member 15 is firmly fixed to the base portion 19 by, for example, welding. One end of each connecting member 15 is provided with an elongated hole 16 extending in the rubber extrusion direction. A first fixture 17 passing through the long hole 16 is fixed to the upper surface 7S of the gear pump 7 in the extruder 2 in this example. By connecting the calender device 4 and the extruder 2 only on the upper surface side of the gear pump 7 in this way, the work of changing the interval L can be performed quickly and easily. A bolt or the like can be preferably used as the first fixing member 17, and in particular, a wing bolt and a thumb bolt that can be attached and detached without a tool can be more preferably used.

In the connecting tool 18 of this example, the connecting members 15, 15 are arranged at different heights. Specifically, one connecting member 15 is fixed to the upper surface of the base portion 19 , and the other connecting member 15 is fixed to the lower surface of the base portion 19 . The upper surface 7S of the gear pump 7 is also a stepped surface having a first surface 7SU on the high side to which one connecting member 15 is fixed and a second surface 7SL on the low side to which the other connecting member 15 is fixed. It is formed. Thus, by making the heights of the connecting members 15 and 15 different, it is possible to increase the rigidity when connecting the calender device 4 and the extruder 2.

The interval defining section 5 of this example includes an actuator 22 that moves one of the calendar device 4 and the extruder 2 relative to the other of the calendar device 4 and the extruder 2 in the rubber extrusion direction.

As shown in FIGS. 1 and 2, the actuator 22 includes a guide 23 extending in the rubber extrusion direction and a driving means 24 for moving one of the calender device 4 and the extruder 2 along the guide 23 in this example. This example shows a case where the extruder 2 is fixed to the installation surface 1S of the manufacturing apparatus 1 and the calendar device 4 moves in the rubber extrusion direction.

As the guide 23, for example, a pair of rails or guide shafts fixed to the installation surface 1S is used. Further, the calendar device 4 is provided with a moving body 25 such as a bearing for linear movement guided by a guide 23 . The moving body 25 may be, for example, a wheel that can roll on a rail.

A ball screw mechanism is employed as the driving means 24 . Specifically, the driving means 24 includes a screw shaft 24A that is rotatably supported in parallel with the guide 23, and this screw shaft 24A is rotationally driven by a driving machine M such as a motor. The calendar device 4 is also provided with a nut portion 26 that meshes with the screw shaft 24A. As the driving means 24, a gear rack mechanism can be adopted instead of the ball screw mechanism.

In this example, in the unlocked state of the first fixture 17 in the connector 18, the actuator 22 is operated to adjust and change the distance L. FIG. After that, by locking the first fixture 17, the calender device 4 and the extruder 2 can be connected in the changed state.

However, it is also possible to provide the actuator 22 with a braking function to prevent the calendar device 4 from moving after the interval L is adjusted or changed by the actuator 22 . In this case, the actuator 22 constitutes the space defining portion 5, and the connector 18 can be eliminated.

In the manufacturing apparatus 1, the calendar device 4 may be fixed to the installation surface 1S, and the extruder 2 may be configured to move in the rubber extruding direction.

Next, a method for manufacturing the rubber strip G will be described. In this manufacturing method, as shown in FIG.
(1) a step Sa of extruding an unvulcanized rubber g from an extruder 2 equipped with a die 8;
(2) A step Sb of pressing the rubber g extruded from the die 8 into a ribbon-shaped rubber strip G by a calender roll 3 disposed on the downstream side of the extruder 2 in the rubber extruding direction;
(3) A step Sc (not shown) of changing the gap L between the die 8 and the calendar roll 3 based on the state of the rubber g extruded from the die 8 is included.

The state of the rubber g extruded from the die 8 means the state of wave-like deformation of the rubber g in the region Y when the manufacturing apparatus 1 is stopped, as shown in FIG. Then, when the deformed portions of the rubber g are likely to stick to each other or stick together to form a lump g1 (shown in FIG. 4(b)), the interval L is changed. To change the interval L, for example, the first fixture 17 of the connector 18 is unlocked, the actuator 22 is operated, and the interval L is adjusted and changed. After that, the first fixture 17 is brought into a locked state, thereby connecting the calender device 4 and the extruder 2 in the changed state.

Although the particularly preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the illustrated embodiments and can be modified in various ways.

1 rubber strip manufacturing device 2 extruder 3 calender roll 4 calender device 5 interval regulating part 8 die 15 connecting member 16 long hole 17 first fixture 22 actuator g rubber G rubber strip L interval

Claims (4)

An apparatus for manufacturing a ribbon-like rubber strip, comprising:
an extruder with a die for extruding unvulcanized rubber;
a calendering device disposed on the downstream side of the extruder in the rubber extruding direction and having a calendering roll that presses the rubber extruded from the die to form a ribbon-shaped rubber strip;
a gap defining part for changing the gap between the die and the calender roll ;
The interval defining part includes a connecting member that connects the calendar device and the extruder,
A rubber strip including a long hole extending in the rubber extrusion direction and a first fixture fixed to one of the calendar device and the extruder through the long hole on at least one end side of the connecting member. manufacturing equipment. 2. The rubber strip manufacturing apparatus according to claim 1, wherein the interval defining unit includes an actuator that moves one of the calender device and the extruder relative to the other of the calender device and the extruder in a rubber extruding direction. . 3. The apparatus for manufacturing a rubber strip according to claim 1 , wherein said interval regulating part can change said interval within a range of 10 to 50 mm . A method for manufacturing a ribbon-like rubber strip, comprising:
extruding unvulcanized rubber from an extruder equipped with a die;
a step of pressing the rubber extruded from the die to form a ribbon-shaped rubber strip with a calender roll of a calendering device disposed on the downstream side of the extruder in the rubber extruding direction;
changing the gap between the die and the calender roll based on the state of the rubber extruded from the die;
fixedly connecting the extruder and the calender device after changing the spacing.

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