JP2009132076A - Strip rubber extrusion apparatus and strip rubber extrusion method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a strip rubber extrusion apparatus capable of keeping the quality relating to swell without elongating a shaping time than in a conventional apparatus and further capable of suppressing rubber facilities from become large in size when reducing the thickness of an extruded strip. <P>SOLUTION: In the strip rubber extrusion apparatus 1 extruding a strip rubber S having a predetermined cross-sectional shape from a shaping die 2, at least two slit of a first slit 2a and a second slit 2b are formed in the extruding die 2, the first slit 2a and the second slit 2b are arranged while displacing the same in a slit short side direction and arranged such that there is an overlapping area in a slit long side direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a strip rubber extrusion apparatus and a strip rubber extrusion method for extruding a strip rubber having a predetermined cross-sectional shape from a molding die.

  Conventionally, from the viewpoint of productivity and work efficiency, a continuous molding facility for forming a rubber member constituting a tire by sequentially winding a strip rubber around a rotating support (molding drum) has been proposed (for example, the following) Patent Documents 1 and 2). In the continuous molding method in which the strip rubber is sequentially wound, since a thin strip-shaped strip rubber is laminated, a rubber member having a desired shape can be easily obtained as compared with the conventional molding method using sheet bonding.

  The equipment disclosed in Patent Document 1 includes a supply device that can move in parallel with a drum shaft on a drum that is driven to rotate, and this supply device is arranged on a base in parallel with the drum shaft via a lateral feed device. It is equipped with a movable column. As a result, automatic winding can be performed continuously and accurately while reciprocating the strip rubber on the rotationally driven drum.

Such a strip rubber is extruded in the form of a sheet having a small thickness and a predetermined width dimension. With regard to this cross-sectional shape, there is a demand for further reducing the thickness and winding it around a rotating support. . The reason is that demand for higher performance tires and ultra flat tires is increasing, and it is preferable to reduce the thickness of the strip rubber in order to manufacture tire constituent members with higher accuracy.
JP 2004-35838 A JP 2006-82277 A

  In order to reduce the thickness of the extruded strip rubber, it is conceivable to reduce the length (gap) in the short side direction of the slit formed in the molding die. At present, the width is about 0.6 mm, but it is necessary to narrow this to about 0.1 to 0.4 mm. If the gap between the slits is narrowed, it must be extruded at a higher pressure. However, since the apparatus has a pressure resistance, extrusion molding exceeding the pressure resistance cannot be performed.

  Moreover, although it can extrude at a low pressure if it extrudes slowly, there exists a problem that molding time takes. Furthermore, the higher the pressure, the larger the swell (a phenomenon in which the rubber swells immediately after being pushed out from the slit of the molding die and the cross section of the rubber becomes larger than the slit). There is a problem that it must be made smaller.

  In the apparatus disclosed in Patent Document 2 below, a strip rubber is extruded from two slits in which molding bases are arranged side by side in parallel, and the thickness of the strip rubber is reduced by a calender roll provided on the front side of the molding base. I try to make it thinner. If the calender roll is used, the molding die can be made thin with the same shape as the conventional one, but another problem arises that the equipment is enlarged.

  The present invention has been made in view of the above circumstances, and its object is to maintain the quality related to the swell without reducing the molding time when the thickness of the extruded strip is reduced, and further, the rubber To provide a strip rubber extrusion device and a strip rubber extrusion method capable of suppressing an increase in size of equipment.

In order to solve the above problems, a strip rubber extrusion device according to the present invention is as follows.
In a strip rubber extrusion device for extruding and molding a strip rubber having a predetermined cross-sectional shape from a molding die,
At least two slits of a first slit and a second slit are formed in the molding die, the first slit and the second slit are shifted in the slit short side direction, and an overlapping region exists in the slit long side direction. It is characterized by being arranged like this.

  The operation and effect of the strip rubber extrusion device having such a configuration will be described. The molding die is formed with at least two slits, a first slit and a second slit. For example, if the cross-sectional shape of the conventional slit is long side length (W) × short side length (t), the cross-sectional shape of each slit is long side length (W) × short side length (t / 2). In this way, it is possible to reduce the gap between the slits while keeping the overall cross-sectional area substantially the same. Further, since the cross-sectional areas are substantially the same, the extrusion can be performed at a pressure that is approximately the same level as the conventional one or slightly higher. Therefore, it is not necessary to make the pressure higher, and the problem of swell does not occur. Further, since the strip rubber is pushed out at least from the first slit and the second slit, there is no problem that the winding time becomes long. Furthermore, since the thickness of the strip rubber can be reduced without using a calendar roll, there is no problem of increasing the size of the equipment.

  Furthermore, in the present invention, regarding the arrangement of the first slit and the second slit, they are arranged so as to be shifted in the slit short side direction, and are arranged so that there is an overlapping region in the slit long side direction. When strip rubber is wound around a molding drum, adjacent strip rubbers must be partially overlapped. In such a case, by arranging the slits as described above, it is possible to easily perform winding in a state where there is an overlap.

  In the present invention, the interval between the first slit and the second slit in the slit short side direction is preferably set to at least twice the length in the slit short side direction.

  If the distance between the strip rubbers extruded from at least two slits is narrow, the strip rubbers stick together before being wound around the forming drum, and a situation in which they cannot be wound into a desired shape may occur. Therefore, by setting the distance as described above, a plurality of strip rubbers can be wound around the molding drum at the same time.

In order to solve the above problems, a strip rubber extrusion method according to the present invention includes:
In a strip rubber extrusion method of extruding a strip rubber having a predetermined cross-sectional shape from a molding die,
Forming at least two slits, a first slit and a second slit, in the molding die;
The first slit and the second slit are arranged so as to be shifted in the slit short side direction, and are arranged so that there is an overlapping region in the slit long side direction.

  The operation and effect of the strip rubber extrusion method with such a configuration is as described above. That is, it can be extruded at a pressure that is approximately the same level as that of the prior art or a slightly higher pressure, and no swell problem occurs. Further, since the strip rubber is pushed out at least from the first slit and the second slit, there is no problem that the winding time becomes long. Furthermore, since the thickness of the strip rubber can be reduced without using a calendar roll, there is no problem of increasing the size of the equipment.

  A preferred embodiment of a strip rubber extrusion device according to the present invention will be described with reference to the drawings. FIG. 1 is a conceptual diagram showing a configuration of equipment using a strip rubber extrusion device.

<Overview of the entire facility>
In FIG. 1, a strip rubber extrusion device 1 includes a molding die 2, a gear pump 3, and an extruder 4. The molding die 4 includes a mold part that can extrude the strip rubber S having a predetermined cross-sectional shape. The extruder 4 includes a screw 5 capable of kneading rubber and a hopper 6 capable of feeding a rubber material.

  The rubber material is not particularly limited, and general-purpose rubbers such as natural rubber, styrene-butadiene rubber (SBR), butadiene rubber (BR), and isoprene rubber (IR) can be used.

  The gear pump 3 includes two gears 3 a and supplies a predetermined amount of rubber toward the molding die 2. A pressure sensor 7 is provided in the vicinity of the outlet of the gear pump 3 to detect the pressure at which the gear pump 3 sends out rubber. The gear pump 3 is driven by the first servo motor 8, and the rotation speed of the gear pump 3 is automatically and accurately controlled by the control device 9 via the first servo motor 8 based on the pressure detected by the pressure sensor 7. can do. In FIG. 1, the two gears 3 a are arranged in the vertical direction for convenience of illustration, but are actually arranged in a plane direction (a direction in which the axis of the gear 3 a is up and down).

  The strip rubber S extruded from the strip rubber extrusion device 1 is sequentially wound around the outer periphery of a molding drum 10 (corresponding to a rotary support). The forming drum 10 is rotationally driven in the counterclockwise direction (indicated by R) in the figure by the second servo motor 12, and the rotation speed thereof is constant. Further, a driving device 13 is provided for moving the strip rubber extruding device 1 in the axial direction (direction perpendicular to the paper surface of FIG. 1) and the horizontal direction of the paper surface of FIG. It is controlled by the control device 9 together with the motor 12.

<Configuration of the die for molding>
Next, a preferred embodiment of the molding die 2 will be described with reference to FIG. FIG. 2 is a front view of the molding die 2. As can be seen from this figure, two slits, a first slit 2a and a second slit 2b, are formed. The two slits have the same cross-sectional shape, and the width (long side length) W and the height (short side length) t are the same. The two slits are arranged so as to be parallel to each other, and are arranged in a state of being separated by a distance y in the short side direction. This y is preferably y ≧ 2t (more than twice the thickness of the strip rubber).

  When extruding a plurality of strip rubbers S at the same time, if they are too close to each other, the strip rubbers S may be bonded to each other before being attached to the molding drum 10 and the desired winding cannot be performed. There is. Therefore, such a problem can be eliminated by separating the necessary minimum distance y.

  Further, the first slit 2a and the second slit 2b have an overlapping region indicated by x in the long side direction. When the strip rubber S is wound around the molding drum 10, the adjacent strip rubbers S are wound in a partially overlapping state. Therefore, when extruding a plurality of strip rubbers S, it is preferable to extrude in consideration of such overlap. The length x of the overlapping region can be appropriately determined in consideration of the shape and characteristics of the tire component to be manufactured.

  FIG. 3A shows a case where one slit 20 is provided in the conventional configuration. Assume that W = 35 mm and t = 0.6 mm. FIG. 3B shows a configuration example in which the gap of the slit 21 is halved (t = 0.3) in order to obtain the conventional strip rubber S having a half thickness. By simply changing from (a) to (b), the pressure at the time of extrusion increases and various problems such as pressure resistance and swell of the apparatus occur.

  On the other hand, as in the present invention shown in FIG. 2, by forming the two slits 2a and 2b with the gaps halved (t = 0.3), the level is almost the same as the conventional level or slightly higher. It can be extruded by pressure, and the above problem does not occur.

  FIG. 4 shows a state when winding. It winds so that adjacent strip rubber | gum S may overlap partially. FIG. 5 is a diagram comparing the winding state (a) according to the present invention and the winding state (b) according to the prior art. By reducing the thickness of the strip rubber S, the level difference when stacked is reduced, and the tire constituent member can be manufactured in a shape closer to the designed shape.

<Rubber winding action>
Next, a method (particularly at the start of application) of molding a tire component using the above-described strip rubber extrusion device (hereinafter abbreviated as an extrusion device) will be described. FIG. 6 is a flowchart showing an example of a procedure when starting molding of a rubber member.

  First, the extrusion device 1 moves forward (# 1) and is brought close to the forming drum 10 as shown in FIG. At this time, a predetermined interval is provided between the molding die 2 and the outer peripheral surface of the molding drum 10. The timing at which the extrusion device 1 is brought close to the molding drum 10 is not particularly limited as long as the predetermined interval is provided until the rubber strip S is discharged.

  Next, the rubber material adjusted in the previous step is put into the hopper 6 of the extruder 4. Here, the rubber material is not particularly limited. For example, the rubber material is a general-purpose rubber raw material such as natural rubber, styrene-butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), etc. And prepared by kneading and heat crosslinking. Moreover, there is no restriction | limiting in particular as a shape of the rubber material thrown in, For example, shapes, such as a ribbon shape, a sheet form, a pellet form, are mentioned. The charged rubber material is kneaded by the screw 5 of the extruder 4, sent out to the front end side in the extrusion direction, and supplied to the gear pump 3 (# 2, 3). The rubber material supplied to the gear pump 3 is sent to the outlet side toward the molding die 2 by a pair of rotating gears 3a (# 4).

  When the strip rubber S is sent out to the outlet side of the gear pump 3, the outlet side pressure in the gear pump 3 is detected by the pressure sensor 7 (# 5). The detection result is sent to the control device 9 and compared with a preset pressure value. When the detected pressure value is equal to or greater than the set value, the molding drum 10 starts rotating after a predetermined time has elapsed from that point (# 6, 7).

  That is, the rotation of the forming drum 10 is started after the gear pump 3 is driven for a predetermined time with reference to the time point when the detected pressure value becomes equal to or higher than the predetermined pressure value. By driving the gear pump 3 for a predetermined time, a predetermined amount of the rubber strip S is discharged to the molding drum 10 as shown in FIG. Furthermore, the rotation of the molding drum 10 is started thereafter, and as shown in FIG. 7C, the rubber strip S at the start of the discharge is not agglomerated but secured to the molding drum 10. Is done.

  The extrusion apparatus 1 moves backward after the forming drum 10 is rotated several times or before it rotates once (# 8), and a predetermined interval is provided between the forming drum 10 and the extrusion apparatus 1. The molding drum 10 is reciprocated in the axial direction in accordance with the cross-sectional shape of a desired tire constituent member while being rotationally driven in the R direction (# 9). Thereby, the rubber strip S is wound spirally along the circumferential direction. The driving of the molding drum 10 and the extrusion device 1 is controlled by the control device 9, and a control program for that purpose is input to the control device 9 in advance.

  While the rubber strip S is continuously extruded, the pressure sensor 7 detects the inlet side pressure in the gear pump 3. The detection result is sent to the control device 9 and controlled so that the detected pressure value matches the preset pressure value.

<Rubber member molding method (at the end of pasting)>
Next, a process at the end of molding of the tire constituent member will be described with reference to a flowchart of FIG. 8 and a schematic diagram of FIG. In step # 9 of the flowchart of FIG. 8, the rubber strip S is gradually wound around the molding drum 10. When the winding process is to be terminated, a termination process start command is issued (# 10 in FIG. 8). Thereby, the gear pump 3 stops first (# 11). The gear pump 3 is stopped immediately before the rotation of the molding drum 10 is stopped (see FIG. 9A). Immediately after the gear pump 3 is stopped, the gear pump 3 is reversely rotated (# 12). Immediately after this, the forming drum 10 is also stopped (# 13, FIG. 9B). The direction in which the gear pump 3 is rotated in the reverse direction is opposite to the direction in which the rubber strip S is extruded. By rotating the gear pump 3 in the reverse direction, the residual pressure on the outlet side in the gear pump 3 can be eliminated. Although the rotation of the forming drum 10 is stopped immediately after the rotation of the gear pump 3 is stopped, the rotation is not limited to this and may be performed simultaneously.

  After the reverse rotation of the gear pump 3 is started, the pressure on the outlet side in the gear pump 3 is detected by the pressure sensor 7. Then, it is determined whether or not the pressure value has decreased to a preset set value (# 14). When it is detected that the gear pump 3 has decreased to a predetermined level, the reverse rotation of the gear pump 3 is stopped (# 15). Next, as shown in FIG. 9C, the extrusion device 1 is advanced (approached) in the direction of the forming drum 10 (# 16).

  When the extrusion device 1 is brought closer to the molding drum 10, the rubber strip S located between the molding drum 10 and the molding die 2 is slackened. Therefore, in order to prevent this sagging phenomenon, the molding drum 10 is Again, it is rotated in the counterclockwise direction R (# 17). Thereby, the extrusion apparatus 1 can be brought close to the forming drum 10 so that no sagging occurs. Next, the molding die 2 comes into contact with the rubber surface wound around the molding drum 10 (# 18, FIG. 9D). The forward drive of the extrusion device 1 is stopped at the position just touched (# 19). It is possible to calculate in advance how far the extrusion device 1 is advanced to determine whether the molding die 2 contacts the rubber surface. Based on this calculated value, the amount by which the extrusion apparatus 1 is advanced can be controlled.

  Simultaneously or substantially simultaneously with the contact of the molding die 2 with the rubber surface, the rotational driving of the molding drum 10 is stopped (# 20). The degree of contact with the rubber surface may be lightly touched, or may be contacted so as to push the surface slightly. Thereby, the rubber strip S can be cut more reliably. Next, the extrusion apparatus 1 is retracted in a direction away from the forming drum 10 (# 21). During this backward movement, the rubber strip S is cut at the tip of the molding die 2. Since there is no residual pressure, the rubber strip S can be cut reliably. Further, the rubber strip S can be cut without forcibly pulling, and the uniformity is not adversely affected.

  When the next tire constituent member is continuously formed, the process returns to # 1, the extrusion device 1 is brought close to the forming drum 10, and the tire constituent member is formed according to the above-described procedure. In such a case, the exit side of the gear pump 3 is filled with a rubber material to some extent, but even in such a state, the rubber strip S can be discharged without excess or deficiency at the start of molding of the tire constituent member. it can.

<Another embodiment>
In the present embodiment, the configuration in which the strip rubber S is supplied from the extrusion device 1 to the molding drum 10 without using a roller or the like has been described. However, the strip rubber S is guided to the molding drum 10 using a guide mechanism such as a roller. May be.

  In the present embodiment, the extrusion device 1 is moved by the driving device 13 along the axial direction of the molding drum 10, but the molding drum 10 may be moved in the axial direction.

  In the present embodiment, the number of slits is two, but three or more may be provided.

Conceptual diagram showing the configuration of equipment using strip rubber extrusion equipment The figure which shows the structural example of the nozzle | cap | die for shaping | molding which concerns on this embodiment The figure which shows the structural example of the nozzle | cap | die for shaping | molding which concerns on a prior art The figure which shows the winding state of the strip rubber The figure which compares and shows the winding state of strip rubber Flow chart showing an example of a procedure at the start of molding of a tire constituent member Schematic showing the state at the start of molding of tire components by the strip build method Flow chart showing an example of the procedure at the end of molding of the tire component Schematic showing the state at the end of molding of tire components by strip build method

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Strip rubber extrusion apparatus 2 Mold base 2a 1st slit 2b 2nd slit 10 Molding drum S Strip rubber

Claims (3)

In a strip rubber extrusion device for extruding and molding a strip rubber having a predetermined cross-sectional shape from a molding die,
Forming at least two slits, a first slit and a second slit, in the molding die;
A strip rubber extrusion apparatus, wherein the first slit and the second slit are arranged so as to be shifted in the slit short side direction, and are arranged so that there is an overlapping region in the slit long side direction.   The strip rubber extrusion device according to claim 1, wherein an interval in the slit short side direction of the first slit and the second slit is set to at least twice the length in the slit short side direction. In a strip rubber extrusion method of extruding a strip rubber having a predetermined cross-sectional shape from a molding die,
Forming at least two slits, a first slit and a second slit, in the molding die;
A strip rubber extruding method characterized in that the first slit and the second slit are arranged so as to be shifted in the slit short side direction, and are arranged so that there is an overlapping region in the slit long side direction.