JP2023032724A - Rubber member manufacturing method and apparatus - Google Patents

Abstract

To provide a rubber member manufacturing method and apparatus capable of manufacturing a rubber member having a desired cross-sectional shape with high productivity by molding an extruded unvulcanized rubber.SOLUTION: There is provided a rubber member manufacturing method in which: when a rubber member S that is molded by extruding an unvulcanized rubber R from a die 3 provided at a front end of an extruder 2 is placed on a rotary drive roller 5a installed in front of the die 3 and pulled forward, a separation distance L between the die 3 and the rotary drive roller 5a on which the rubber member S is placed is changed, by using a separation distance variable mechanism 6, according to an extrusion speed V of the unvulcanized rubber R, so that a time for relaxing a residual stress of the rubber member S between the die 3 and the rotary drive roller 5a is adjusted; and even if the extrusion speed V changes, the rubber member S having a desired cross-sectional shape can be obtained by correcting variation in a magnitude of the residual stress.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a method and an apparatus for manufacturing a rubber member, and more particularly to a method and an apparatus for manufacturing a rubber member that can produce a rubber member molded by extruding unvulcanized rubber into a desired cross-sectional shape with good productivity. It is a thing.

Rubber members manufactured by extruding unvulcanized rubber with an extruder are used in the manufacturing process of rubber products such as tires. The unvulcanized rubber is molded into a predetermined shape and extruded when passing through the extrusion channel at the front end of the extruder (see, for example, Patent Document 1).

Unvulcanized rubber has the property of expanding in the width direction and thickness direction and contracting in the longitudinal direction (hereinafter referred to as swell) when released from the restraint of the die. This swell occurs because strain energy (residual stress) remaining in the shaped unvulcanized rubber attempts to return the unvulcanized rubber to the state before it was shaped. This swell causes the cross-sectional shape of the extruded rubber member to change over time, which is an obstacle to securing a desired cross-sectional shape.

Therefore, if the unvulcanized rubber is extruded at a slower speed in order to reduce the residual stress, there is a demerit that the productivity of the rubber member is lowered. Alternatively, if the residual stress is reduced by increasing the stress relaxation time by making it longer than the extrusion channel of the die, there is a disadvantage that the load on the extrusion equipment becomes excessive. Furthermore, when the extrusion speed is different, the time required for the stress to be relieved by the die changes, and accordingly the magnitude of the residual stress also changes, resulting in variation in the cross-sectional shape of the rubber member. Therefore, there is room for improvement in manufacturing a rubber member molded by extruding unvulcanized rubber in a desired cross-sectional shape with good productivity.

JP 2009-143165 A

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for manufacturing a rubber member that can produce a rubber member shaped by extruding unvulcanized rubber into a desired cross-sectional shape with high productivity.

In order to achieve the above object, the method for producing a rubber member of the present invention comprises extruding unvulcanized rubber from a die attached to the front end of an extruder, and placing the rubber member shaped by the die in front of the die. In the method for manufacturing a rubber member, the distance between the die and the drawing means on which the rubber member is placed is changed according to the extrusion speed of the unvulcanized rubber. It is characterized by

The rubber member manufacturing apparatus of the present invention comprises an extruder for extruding unvulcanized rubber, and drawing means disposed in front of a die attached to the front end of the extruder, wherein the unvulcanized rubber is In the rubber member manufacturing apparatus in which the rubber member shaped by the die is drawn out forward while being placed on the drawing means, the separation distance between the die and the drawing means on which the rubber member is placed is It is characterized by having a separation distance variable mechanism that changes according to the extrusion speed of the vulcanized rubber.

According to the present invention, the separation distance is changed according to the extrusion speed of the unvulcanized rubber, so that the extruded rubber member is subjected to a time period during which residual stress is relieved by the drawing means. can be adjusted. As a result, even if the extrusion speed changes, the variation in residual stress can be corrected, which is advantageous for obtaining a rubber member having a desired cross-sectional shape. In addition, since it is not necessary to forcibly slow down the extrusion speed in order to secure a rubber member having a desired cross-sectional shape, it is advantageous for manufacturing rubber members with good productivity.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which illustrates embodiment of the manufacturing apparatus of the rubber member of this invention by the side view. FIG. 2 is an explanatory diagram illustrating the manufacturing apparatus of FIG. 1 in plan view; FIG. 2 is an explanatory diagram illustrating a state in which the rotary drive roller of FIG. 1 is moved; It is explanatory drawing which shows the modified example of the drawer means of FIG. It is an explanatory view which illustrates another embodiment of a manufacturing device of a rubber member by side view. It is explanatory drawing which expands and illustrates the circumference|surroundings of the drawer means of FIG. FIG. 6 is an explanatory diagram illustrating a state in which one of the rotary drive rollers in FIG. 5 is moved downward; It is explanatory drawing which illustrates the modification of the drum body of FIG. 1 by the cross-sectional view of the left half. FIG. 9 is an explanatory diagram showing the drum body of FIG. 8 in a side view;

BEST MODE FOR CARRYING OUT THE INVENTION A method and an apparatus for manufacturing a rubber member according to the present invention will be described below based on embodiments shown in the drawings.

An embodiment of a rubber member manufacturing apparatus 1 illustrated in FIGS. 1 and 2 extrudes an unvulcanized rubber R to manufacture a strip-shaped rubber member S having a desired cross-sectional shape. The cross-sectional shape of the rubber member S is not particularly limited, and a desired shape such as a circular shape, an elliptical shape, a triangular shape, a square shape, and other polygonal shapes is adopted. The width dimension (diameter dimension) of the rubber member S is, for example, about 5 mm to 30 mm.

This manufacturing apparatus 1 includes an extruder 2 for extruding unvulcanized rubber R, a drawing means 5 arranged in front of the extruder 2, and a separation distance variable mechanism 6. As shown in FIG. This embodiment further comprises a support roller 7, a transport conveyor 8 and a drum body 9 arranged in front of the pull-out means 5. As shown in FIG. The support rollers 7, the transport conveyor 8 and the drum body 9 are optionally installed according to the needs of the rubber member S production line. The horizontal direction of the drawing is the front-rear direction of the manufacturing apparatus 1, and the left and right sides of the drawing are the front and rear of the manufacturing apparatus 1, respectively.

The extruder 2 includes a cylindrical cylinder 2a, a screw 2b arranged inside the cylinder 2a, and a head 2c installed at the front end of the cylinder 2a. A die 3 is detachably attached to the front end of the head 2c. The die 3 is formed with an extrusion channel 4 communicating in the front-rear direction. The extrusion channel 4 communicates with the inside of the cylinder 2a. As the extruder 2, various types of known specifications can be used. For example, a specification having a gear pump in the head 2c may be used.

The unvulcanized rubber R introduced into the cylinder 2a is fed forward inside the cylinder 2a by a screw 2b rotated by a drive motor to have its viscosity lowered (plasticized). The unvulcanized rubber R passes through the extrusion channel 4 to be molded, and is extruded as a rubber member S from the outlet of the extrusion channel 4 that opens in the front end face of the die 3 . The outline of the cross-sectional shape of the rubber member S is determined by the cross-sectional shape of the extrusion channel 4 . Since the die 3 is detachable from the head 2c, the die 3 in which the extrusion channel 4 having a corresponding cross-sectional shape is formed is attached to the head 2c according to the cross-sectional shape of the rubber member S to be manufactured.

The drawing means 5 is arranged in front of the die 3, and the rubber member S shaped by the die 3 is placed thereon. The drawing means 5 draws out the rubber member S while placing it thereon. In this embodiment, a rotary driving roller 5a is employed as the drawing means 5. As shown in FIG. The rotary driving roller 5a extends in a direction crossing the rubber member S placed thereon. That is, the extending direction of the axial center of the rotary drive roller 5a and the extending direction of the rubber member S are perpendicular to each other. The pull-out speed of the rubber member S by the rotation driving roller 5a (pull-out means 5) is controlled by a controller 6c, which will be described later.

The separation distance variable mechanism 6 changes the separation distance L between the die 3 and the rotary drive roller 5a on which the rubber member S is placed according to the extrusion speed V of the unvulcanized rubber R by the extruder 2 . Specifically, the distance L is the distance between the front end surface of the die 3 and the axis of the rotary drive roller 5a in the front-rear direction.

In this embodiment, the separation distance variable mechanism 6 has a variable drive section 6a for moving the rotary drive roller 5a in the front-rear direction, a guide section 6b, and a control section 6c. As the variable drive unit 6a, various fluid cylinders, rods that move back and forth by a servomotor, and the like can be used. The guide portion 6b guides the rotating drive roller 5a, which moves back and forth, in the front and back direction so that it does not deviate.

The control section 6c controls the movement of the variable drive section 6a. A computer is used as the controller 6c. Data on the extrusion speed V is input to the control unit 6c. This extrusion speed V is obtained by directly or indirectly detecting the flow speed of the unvulcanized rubber R passing through the head 3 and the die 4. If so, it can be grasped using data such as the number of revolutions of the gear pump. The control unit 6c controls the movement of the variable drive unit 6a based on the data of the extrusion speed V to set the separation distance L to the target value. In this embodiment, the pull-out speed of the rotary drive roller 5a (pull-out means 5) is also controlled by the controller 6c, but the pull-out speed can also be controlled by another controller.

A rubber member S is placed on the support roller 7, and the rubber member S hangs down due to its own weight between the support roller 7 and the rotation drive roller 5a. This hanging portion of the rubber member S becomes an extra length in the production line of the rubber member S (it becomes a festoon portion).

A rubber member S is placed on the transport conveyor 8, and the placed rubber member S is transported forward. Various known types such as a type equipped with a rubber or resin conveyor belt can be adopted for the transport conveyor 8 .

A rubber member S is wound around the outer peripheral surface of the cylindrical drum body 9 using a pressure roller or the like. The rubber member S may be wound around the outer peripheral surface of another member already wound around the outer peripheral surface of the drum body 9 . Therefore, the rubber member S is wound directly or indirectly around the outer peripheral surface of the drum body 9 . The drum body 9 is not limited to a so-called molding drum, and may be a rigid core having an outer peripheral surface having the same shape as the inner peripheral surface of the finished tire.

A slide mechanism 9 a is connected to the drum body 9 . In this embodiment, an actuator such as a hydraulic cylinder is used as the slide mechanism 9a. As the cylinder rod of the slide mechanism 9a advances and retreats, the drum body 9 slides in the width direction of the drum. The slide mechanism 9a slides the drum body 9 during rotation. In this drum body 9, the rubber member S is formed into an annular rubber member Sc. The ring-shaped rubber member Sc is a concept that also includes a cylindrical rubber member.

The transfer conveyor 8 may be slid without sliding the drum body 9 in the width direction of the drum, or both the drum body 9 and the transfer conveyor 8 may be slid. When the transport conveyor 8 is slid, for example, the support roller 7, the rotary driving roller 5a and the extruder 2 are slid in synchronism with the transport conveyor 8. As shown in FIG.

Next, an example of the procedure of the method for manufacturing a rubber member according to the present invention will be described.

As illustrated in FIGS. 1 and 2, an unvulcanized rubber R is extruded from a die 3 attached to the front end of an extruder 2 to form a rubber member S. FIG. The rubber member S is placed on the rotary drive roller 5a and is stretched substantially without slack between the die 3 and the rotary drive roller 5a. In this state, the rubber member S is drawn forward by the rotary drive roller 5a and placed on the transport conveyor 8 via the support roller 7. As shown in FIG.

The speed at which the rubber member S is pulled out by the rotary drive roller 5a is set to a level at which the rubber member S is not slackened at the slowest and within a range in which the rubber member S is not broken. For example, when the cross-sectional area of the rubber member S on the rotary drive roller 5a is defined as the speed at which the cross-sectional area of the rubber member S on the rotary drive roller 5a is equivalent to the cross-sectional area defined by the die 3 as the extrusion speed, the allowable range of the withdrawal speed is 60% of this extrusion speed. % to 200%. Even if the withdrawal speed is slower than this extrusion speed (even if it is about 60% of the extrusion speed), the cross-sectional area of the rubber member S becomes larger than the cross-sectional area defined by the die 3 due to swelling, so it does not loosen. state may occur. Next, the rubber member S is transported to the drum body 9 by the transport conveyor 8 .

The drum body 9 is slid in the width direction of the drum by the slide mechanism 9a while rotating. The rubber member S transported by the transport conveyor 8 is pressed against the outer peripheral surface of the drum body 9 by a pressing roller or the like and arranged on the outer peripheral surface of the drum body 9 . As a result, the rubber member S is spirally wound around the drum body 9 while shifting its position in the width direction of the drum. Basically, the conveying speed of the rubber member S by the conveying conveyor 8 and the circumferential speed of the outer peripheral surface of the drum body 9 are controlled to be substantially the same without causing a large difference.

The rubber members S wound adjacent to each other in the width direction of the drum are joined together by their own adhesiveness. The drum body 9 not only slides in one direction in the width direction of the drum, but also slides back and forth in the width direction of the drum if necessary, and the rubber member S may be wound thereon. When the rubber member S is cut to a required length and wound, a cylindrical rubber member Sc is manufactured on the outer peripheral surface of the drum body 9 . Such a cylindrical rubber member Sc becomes, for example, a member forming a tire tread portion.

The rubber member S is shaped by the die 3, but changes in shape over time due to swelling immediately after being released from the restraint of the die 3. If the extruded rubber member S is not restrained by any means, the effect of the swell is greatest immediately after being extruded from the die 3, so it expands more in the width direction and thickness direction and contracts more in the longitudinal direction. As time elapses after being extruded from the die 3, the influence of the swell becomes smaller, and the degree of change in shape of the rubber member S over time becomes smaller.

Here, the rubber member S is placed and adhered to the rotary drive roller 5a, and is temporarily restrained by the rotary drive roller 5a. Therefore, between the die 3 and the rotary drive roller 5a (between the separation distance L), free deformation of the rubber member S caused by the swell is suppressed and the residual stress is relieved. Due to the difference in the length of time for the residual stress to be relaxed, the subsequent shape (cross-sectional shape) of the rubber member S is different.

The faster the extrusion speed V, the shorter the time for the rubber member S to pass between the die 3 and the rotary drive roller 5a (between the separation distance L), so the time for the residual stress to be relaxed becomes shorter. Therefore, if the separation distance L remains unchanged even if the extrusion speed V changes, the subsequent shape (cross-sectional shape) of the rubber member S will be different due to the swell.

The extruder 2 basically continues to extrude the unvulcanized rubber R at an extrusion speed V within a certain allowable range in order to obtain a rubber member S of constant quality, but the extrusion speed V may be changed in the middle. . Further, since the appropriate extrusion speed V differs when the specifications (type of rubber) of the unvulcanized rubber R are different, different extrusion speeds V are set according to the specifications of the unvulcanized rubber R.

Therefore, in the present invention, the separation distance changing mechanism 6 is used to change the separation distance L according to the extrusion speed V as illustrated in FIG. In FIG. 3, the rotary drive roller 5a and the rubber member S before the separation distance L is changed are indicated by thin broken lines. Basically, control is performed such that the faster the extrusion speed V is, the larger the distance L is, and the slower the extrusion speed V is, the smaller the distance L is.

In the present invention, by changing the separation distance L, it is possible to equalize the time for the residual stress of the rubber member S to relax between the die 3 and the rotary drive roller 5a even if the extrusion speed V changes. As a result, variations in the magnitude of residual stress can be corrected, so variation in the shape (cross-sectional shape) of the rubber member S caused by swelling is suppressed, making it easier to secure a desired cross-sectional shape. In this embodiment, since the separation distance L can be adjusted steplessly, it is possible to further reduce the variation in the magnitude of the residual stress and correct it.

Moreover, it is not necessary to forcibly slow down the extrusion speed V to suppress the influence of the swell in order to secure the rubber member S having the desired cross-sectional shape. Therefore, it is advantageous for manufacturing the rubber member S with good productivity.

By using the rubber member S having a desired cross-sectional shape in which variations are suppressed in this way, the annular (cylindrical) rubber member Sc manufactured by spirally winding the rubber member S can be manufactured with higher accuracy. It is advantageous to form the desired shape with As a result, it contributes to the improvement of the uniformity of the tire manufactured using this rubber member Sc.

In this production line of the rubber member S, the excess length of the rubber member S is absorbed between the rotary drive roller 5a and the support roller 7. As shown in FIG. Therefore, even when the rotation of the drum body 9 is temporarily stopped in order to remove the manufactured rubber member Sc from the drum body 9 or at intervals such as when the drum body 9 is replaced, the extruder 2 can continue to extrude the rubber member S as it is. can be done.

The degree of shape change of the rubber member S due to the swell is greatest immediately after extrusion, and decreases as time elapses. Therefore, if free deformation caused by swelling of the rubber member S is suppressed in a region as close as possible to the front end surface of the die 3, variations in the cross-sectional shape of the rubber member S can be reduced, and the rubber member S having a desired cross-sectional shape can be obtained. It becomes more and more advantageous to secure. Therefore, it is preferable that the rotary driving roller 5a is arranged in a region as close as possible to the front end surface of the die 3, and the distance L is, for example, within 50 cm, more preferably within 20 cm.

The degree of swell differs depending on the specifications of the unvulcanized rubber R. Therefore, the appropriate range of the separation distance L to be changed according to the extrusion speed V for each specification of the unvulcanized rubber R should be grasped in advance as advance data and stored in the control unit 6c. When manufacturing the rubber member S, by inputting specific data specifying the specifications of the unvulcanized rubber R into the control unit 6c, the control unit 6c performs Depending on the extrusion speed V, the separation distance L is changed within an appropriate range. As a result, even when the rubber member S is manufactured using unvulcanized rubber R of various specifications, the separation distance L can be more reliably controlled within an appropriate range.

As illustrated in FIG. 4, a belt conveyor 5b can also be used as the pull-out means 5. As shown in FIG. This embodiment differs from the previous embodiment only in the drawer means 5, and the rest of the construction is substantially the same. This belt conveyor 5b is also controlled to change the separation distance L according to the extrusion speed V, like the rotary drive roller 5a of the previous embodiment. When the belt conveyor 5b is used, the contact area with the rubber member S is increased compared to the rotary drive roller 5a, so the rubber member S can be restrained more stably.

In the embodiment of the manufacturing apparatus 1 illustrated in FIGS. 5 and 6, the drawing means 5 comprises a plurality of tandem rotary drive rollers 5a. This embodiment differs from the above-described embodiment only in the drawer means 5, and the rest of the construction is substantially the same. Each rotation driving roller 5a is arranged at a height position of a mounting level on which the rubber member S is mounted. Each rotary drive roller 5a is vertically movable by a variable drive unit 6a such as a fluid cylinder. In this embodiment, there is a separation distance L between the die 3 and the rotary drive roller 5a on which the rubber member S is placed and which is arranged closest to the die 3 .

In this embodiment, according to the extrusion speed V, the separation distance L is changed by moving at least one rotary drive roller 5a below the mounting level by the variable drive unit 6a. As illustrated in FIG. 7, when the rotary drive roller 5a arranged closest to the die 3 is moved below the placement level, the rotary drive roller 5a next to this rotary drive roller 5a is moved to the rubber member. Since S is placed and arranged closest to the die 3, the separation distance L is increased. The rotary drive roller 5a arranged closest to the die 3 and the adjacent rotary drive roller 5a (that is, the two rotary drive rollers 5a arranged on the die 3 side) are moved below the mounting level. As a result, the separation distance L is further increased. To decrease the separation distance L, the opposite operation to the case of increasing the separation distance L may be performed.

In this embodiment, the separation distance L does not change steplessly, but changes to a plurality of preset values based on the arrangement of the respective rotational drive rollers 5a arranged in series. The number of tandemly arranged rotary driving rollers 5a is appropriately determined, but is, for example, about two to five.

The drum body 9 is not limited to a simple cylindrical shape. The outer peripheral surface of the drum body 9 illustrated in FIGS. 8 and 9 has the same profile as the inner peripheral surface of the finished tire. The above-described rigid core can be exemplified as the drum body 9 having such a shape.

In this drum body 9, for example, a rubber member S is spirally wound around both ends in the width direction of the outer peripheral surface of the drum body 9 during rotation to manufacture an annular rubber member Sc. The rubber member S may be directly wrapped around the outer peripheral surface of the drum body 9 or may be wrapped around the outer peripheral surface of another member (inner liner and carcass layer) already wrapped around the outer peripheral surface of the drum body 9 . The rubber member S is spirally wound along the outer peripheral surface of the drum body 9 . In this embodiment, the manufactured annular rubber member Sc becomes a member forming the tire side portion. It is also possible to manufacture a cylindrical rubber member Sc by spirally winding the rubber member S around the central portion in the width direction of the rotating drum body 9 .

It should be noted that the configurations described in each of the above-described embodiments can be applied to other embodiments as far as possible.

1 Rubber Member Manufacturing Apparatus 2 Extruder 2a Cylinder 2b Screw 2c Head 3 Die 4 Extrusion Channel 5 Drawing Means 5a Rotation Drive Roller 5b Belt Conveyor 6 Spacing Distance Variable Mechanism 6a Variable Drive Section 6b Guide Section 6c Control Section 7 Support Roller 8 Conveyor 9 Drum body 9a Slide mechanism S Rubber member Sc Annular (cylindrical) rubber member R Unvulcanized rubber

Claims (7)

Manufacture of a rubber member in which unvulcanized rubber is extruded from a die attached to the front end of an extruder, and the rubber member shaped by the die is placed on a drawer means disposed in front of the die and drawn forward. In the method
A method of manufacturing a rubber member, wherein a distance between the die and the pull-out means on which the rubber member is placed is changed according to an extrusion speed of the unvulcanized rubber. 2. The method of manufacturing a rubber member according to claim 1, wherein a rotary drive roller extending in a direction transverse to said rubber member is used as said pull-out means. 2. The method of manufacturing a rubber member according to claim 1, wherein a belt conveyor is used as said drawing means. A plurality of said drawer means are arranged in series, each of said drawer means is arranged at a height position of a mounting level on which said rubber member is placed, and at least one of said drawer means is positioned below said mounting level. The method for manufacturing a rubber member according to any one of claims 1 to 3, wherein the separation distance is changed by moving. The method of manufacturing a rubber member according to any one of claims 1 to 4, wherein the rubber member is spirally wound around the outer peripheral surface of a drum body arranged in front of the pull-out means to form an annular shape. For each specification of the unvulcanized rubber, the appropriate range of the separation distance to be changed according to the extrusion speed is grasped in advance as prior data and stored in the control unit, and the specification of the unvulcanized rubber is specified. By inputting specific data to the control unit, the separation distance is changed to the appropriate range according to the extrusion speed by the control unit based on the specific data and the prior data. 6. The method for manufacturing the rubber member according to any one of 5. An extruder for extruding unvulcanized rubber, and a drawing means disposed in front of a die attached to the front end of the extruder, wherein the rubber member in which the unvulcanized rubber is shaped by the die is the In an apparatus for manufacturing a rubber member that is pulled forward while being placed on a pull-out means,
An apparatus for manufacturing a rubber member, comprising a separation distance variable mechanism for changing a separation distance between the die and the pull-out means on which the rubber member is placed according to an extrusion speed of the unvulcanized rubber.

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