Extrusion equipment for producing rubber-based products.

Abstract

The present invention relates to an extrusion apparatus (100) for forming a rubber-based product in the form of a thin strip, the apparatus comprising: - a rotating roller (112) having a continuous helical groove (112R) formed on the outer surface (112a) of the roller, the groove comprising a plurality of stripes (112Ra) arranged one after another along the direction of movement of the mixture and spaced apart from each other to produce a thread with a predetermined pitch; and - an arch having protruding threads oriented toward the roller on its inner surface, thereby defining a chamber for plasticizing the mixture with the surface of the roller; the roller and the arch are assembled such that the crests of the thread produced by the helix and the crests of the protruding threads on the arch are substantially in contact with each other.

Description

Technical Field

[0001] This invention generally relates to the production of products made from rubber blends. More specifically, this invention relates to an extrusion apparatus for producing products in the form of thin strips from rubber blends. Background Technology

[0002] In the field of manufacturing products made from rubber compounds (including tires), equipment is used to manufacture molded products in the form of extremely thin strips based on rubber compounds. The manufactured strips can be very wide and can be placed directly on known equipment (including tire forming drums, or "drums") or directly superimposed on another material (e.g., one or more cord layers or layers already placed on the drum) at the exit of the equipment.

[0003] A generally accepted solution for obtaining this result is Figure 1 and Figure 2 The extrusion apparatus 10 shown is disclosed in the applicant's patent EP1343624B1. The extrusion apparatus (or "apparatus") 10 includes a rotating roller (or "roller") 12 that rotates about its axis XX′, the rotating roller 12 having an outer surface 12a. The apparatus 10 also includes an arch 14 having a wall 16 extending between a lateral end (hidden by the roller 12) and an opposite lateral end 16a, defining an inlet orifice at the lateral end hidden by the roller 12 and an extrusion orifice at the opposite lateral end 16a when the extrusion apparatus 10 is closed. The extrusion orifice is defined by the outer surface 12a of the roller 12 and an extrusion plate (or "plate") 18 arranged toward the opposite lateral end 16a of the arch 14. The wall 16, which partially covers at least a portion of the outer surface 12a of the roller 12 circumferentially, includes an inner surface 16b having projecting threads 16c oriented toward the roller 12 and separating continuous sectors 16d. Therefore, a gap is defined between roller 12 and wall 16, which forms a cavity for plasticizing the rubber mixture that forms the thin strip.

[0004] During the production process, the rubber compound is subjected to considerable stress. (Reference) Figure 2 In one embodiment of device 10, rollers 12 arranged relative to dome 14 are along a predetermined direction (see [reference]). Figure 2 Arrow A in the diagram rotates, the predetermined direction depending on the direction of travel of the substrate to be placed on the strip at the equipment exit (see [reference]). Figure 2 (Arrow B in the diagram). The rubber mixture introduced through the inlet hole will follow the path indicated by the strip M. The introduced rubber mixture enters the gap E defined between the inner surface 16b of the wall 16 and the outer surface 12a of the roller 12. 10The rubber compound generates significant shear force at the protruding thread 16c. Therefore, material near the roller may continue to adhere to the roller and bypass the protruding thread, potentially leading to the formation of rubber particles in the strip (e.g., in cases of uneven protruding thread).

[0005] Due to Figure 1 and Figure 2 The strip exiting an extrusion apparatus of the type shown is very thin (e.g., less than 5 mm thick, and in some embodiments, about 0.3 mm), thus requiring assurance that particles are removed from the extrusion apparatus. Therefore, in the extrusion apparatus shown, the present invention relates to forming grooves in the form of a continuous spiral on the outer surface of a roller to remove particles. As the roller rotates, this spiral removes any particles that may be present in the strip formed by the extrusion apparatus. Summary of the Invention

[0006] This invention relates to an extrusion apparatus for forming a rubber-based product in the form of a thin strip, the apparatus comprising a rotating roller, an inlet orifice allowing flow of the rubber mixture, and an arch covering at least a portion of the outer surface of the roller circumferentially, the arch having a wall having protruding threads on the inner surface of the wall oriented toward the roller, thereby defining a chamber for plasticizing the rubber mixture with the surface of the roller, the rubber mixture being pushed from the inlet orifice toward the extrusion orifice in a gap defining the product profile, the gap being defined by the wall of the arch and the outer surface of the roller, characterized in that:

[0007] - A continuous spiral groove is formed on the outer surface of the roller, the groove comprising a plurality of stripes arranged one after another along the direction of movement of the rubber compound, and the stripes are spaced apart from each other to produce a thread with a predetermined pitch;

[0008] The roller and the dome are assembled such that the crests of the thread produced by the continuous helix and the crests of the protruding thread on the dome are substantially in contact with each other.

[0009] In one embodiment of the extrusion apparatus, the extrusion apparatus further includes an extrusion plate that adjustably defines an extrusion orifice with the outer surface of a roller.

[0010] In one embodiment of the extrusion apparatus, each stripe has a cross-section with a predetermined geometry, a circular bottom, and a pointed edge.

[0011] In one embodiment of the extrusion equipment, the angle between the edge of the stripe and the outer surface of the roller is less than or equal to 90°.

[0012] In one embodiment of the extrusion equipment, the stripes have a triangular cross-section.

[0013] In one embodiment of the extrusion equipment, the protruding thread includes:

[0014] - At least two axial threads that extend substantially axially from the wall of the dome toward the outer surface of the roll; and

[0015] - One or more threads oriented in different directions relative to the axial thread, selected from helical threads, converging threads, or diverging threads.

[0016] In one embodiment of the extrusion equipment, the gap defining the product profile defines a product thickness of less than 5 mm.

[0017] In one embodiment of the extrusion apparatus, the dome is pivotally mounted around a rotational axis supported by a support element of the roller.

[0018] The present invention also relates to a method for forming a rubber compound produced by the extrusion equipment of the present disclosure, the method comprising the following steps:

[0019] - The step of introducing the rubber mixture into the equipment through the inlet hole;

[0020] - The step of conveying the rubber compound in a circumferential direction, which is performed by the rollers as they rotate; and

[0021] - The step of advancing the rubber compound until it reaches the extrusion orifice of the device and then exiting the device in the form of a thin strip.

[0022] The present invention also relates to a tire production line including at least one extrusion device of the type disclosed herein, said extrusion device being arranged downstream of at least one extruder for extruding a rubber compound.

[0023] Other aspects of the invention will become apparent from the following detailed description. Attached Figure Description

[0024] The features and various advantages of the invention will become more apparent from the following detailed description and study of the accompanying drawings, in which the same reference numerals denote the same parts, and in the drawings:

[0025] [ Figure 1 ] Figure 1 A perspective view of a known extrusion apparatus for producing molded products based on rubber compounds is shown.

[0026] [ Figure 2 ] Figure 2 Show Figure 1 A schematic diagram of the implementation scheme for the extrusion equipment.

[0027] [ Figure 3 ] Figure 3A perspective view of an embodiment of the extrusion apparatus of the present invention is shown, the extrusion apparatus having a continuous spiral groove formed on the outer surface of its rollers.

[0028] [ Figure 4 ] Figure 4 A perspective view showing an embodiment of the rollers of the extrusion equipment.

[0029] [ Figure 5 ] Figure 5 A cross-sectional side view of an embodiment of the rollers of an extrusion device is shown. Detailed Implementation

[0030] Referring now to the accompanying drawings, in which the same reference numerals denote the same elements. Figure 3 An embodiment of an extrusion apparatus (or “equipment”) 100 for producing products in the form of thin strips of rubber compounds is shown. Equipment 100 may be part of a facility or tire production line.

[0031] It should be understood that the rubber mixture (or "mixture") introduced into device 100 may include all materials required for the production of the product, including but not limited to elastomers (e.g., natural rubber, synthetic elastomers, combinations thereof, and equivalents) and one or more components, such as one or more processing aids, protective agents, and reinforcing fillers. The materials may also include one or more other components, such as carbon black, silica, oils, resins, and crosslinking or vulcanizing agents. During the mixing of the rubber mixture, all components are introduced in a variable manner according to the desired properties of the product (e.g., tire) obtained through the mixing process.

[0032] Still referencing Figure 3 And also refer to Figure 4 and Figure 5 The device 100 includes a rotating roller (or “roller”) 112 having a substantially circumferential outer surface 112a. The roller 112 has a center through which a rotation axis X is defined. 112 -X 112′ A roller 112, extending axially between two opposite ends 112b, 112b′, rotates about its axis of rotation relative to a shaft 114 (its support roller). The roller 112 and the shaft 114 may be integral or they may be configured as two separate components. The roller 112 also includes a pair of shoulders 112c having equal predetermined diameters.

[0033] Equipment 100 further includes Figure 1 and Figure 2 The device 10 includes a vault (not shown) of the type disclosed in the applicant's patent EP1343624B1. As described above and Figure 1 and Figure 2As shown, the dome includes a wall that circumferentially covers at least a portion of the outer surface 112a of the roller 112. The inner surface of the wall has projecting threads oriented toward the roller. As understood by those skilled in the art, the inner surface of the wall has a substantially circumferential profile to guide a flow of rubber mixture into a gap defined between the inner surface of the wall and the outer surface 112a of the roller 112, the gap serving as a chamber for plasticizing the mixture. An inlet orifice and a relative extrusion orifice are located at two lateral ends of the dome (corresponding to shoulders 112c of the roller 112), respectively. During mixture formation, the mixture is pushed from the inlet orifice toward the extrusion orifice through the gap between the wall of the dome and the outer surface 112a of the roller 112.

[0034] It should be understood that the dome is not divided into sectors but has at least two projecting threads (“axial threads”) extending substantially axially from the wall. These two axial threads guide the mixture toward the extrusion orifice so that the mixture is distributed across the width of the extrusion orifice. Other projecting threads in the dome may be oriented in a different direction relative to the axial threads (“directional threads”), such as helical threads, converging threads, or diverging threads.

[0035] Two flanges 116 and 118 are respectively mounted on two shoulders 112c, each flange internally supporting a shoulder (not shown) that interacts axially with a corresponding end of the vault. This allows the vault to be secured to the equipment by one or more known fastening devices (e.g., one or more screws or one or more equivalent devices).

[0036] like Figure 3 As can be seen, support elements 120 and 122 are respectively mounted between flanges 116 and 118, the support elements being circumferentially offset relative to roller 112. Support elements 120 and 122 are rigidly fixed to flanges 116 and 118 by any suitable means (e.g., screws or equivalent fastening devices). It should be understood that flanges 116 and 118 and support elements 120 and 122 can be integrally formed. The dome can be pivotally mounted on support element 120 to allow opening and closing of device 100.

[0037] Roller 112 can be mounted on a frame and rotated by a motor at a predetermined speed. The exact position of roller 112 relative to the frame can be adjusted according to the properties of the mixture and the formed strip (its width and thickness).

[0038] It should be understood that, regarding Figure 1 and Figure 2The extrusion plate (or "plate") of the aforementioned type is arranged internally on the support element 120 such that it defines an extrusion orifice with the outer surface 112a of the roller 112. Therefore, the spacing between the plate and the outer surface 112a of the roller 112 can be adjusted to define the height of the extrusion orifice according to the profile of the strip (e.g., thin strip) of the rubber product to be obtained. The plate may include one or more holes allowing textile yarns or wires to pass through, thereby producing reinforced strips that can be placed directly on a forming drum or template.

[0039] Roller 112 includes means for controlling the internal temperature of the roller, which includes, for example, a mesh system including one or more feed channels 125 and one or more conveying grooves 127 passing through the roller (see...). Figure 5 Therefore, a corresponding conditioning fluid (e.g., water, steam, gas or other known temperature-regulating fluid) or electricity is supplied under the outer surface 112a of the roller 112, thereby regulating the temperature of the mixture during the formation of the mixture.

[0040] Still referencing Figures 3 to 5 A continuous spiral groove 112R is formed on the outer surface 112a of the roller 112 (the surface facing the protruding threads on the dome). The continuous spiral allows the rubber mixture flow to move forward between the continuous spiral and the protruding threads on the wall, thereby effectively plasticizing the mixture. The continuous spiral may include a plurality of stripes 112Ra arranged one after another along the direction of mixture movement (see...). Figure 4 Stripes 112Ra can be spaced apart to create a thread with a predetermined pitch. Stripes 112Ra ensure that the rubber compound moves forward relative to the circumferential direction during the formation of the compound.

[0041] Each stripe 112Ra forms a channel with a predetermined geometry (e.g., a triangular, circular, or basic rectangular cross-section). A circle is defined at the bottom of each stripe 112Ra, and the sharp edges scrape the material during plasticizing. The angle between the edge of the stripe and the outer surface 112a of the roller 112 is preferably 90° or less.

[0042] The roller 112 and the dome of the device 100 are assembled such that the crests of the threads produced by the continuous helix are tangential to the crests of the threads on the dome. In other words, the crests are substantially in contact with each other. When the crests face each other at a sufficiently small distance that the rubber material cannot adhere to the surface of the crests, the crests are said to be in "substantially in contact," thereby preventing the formation of particles in the thin strip formed by the mixture. Therefore, no product will adhere to the outer surface 112a of the roller 112 or the wall of the dome without being pushed by the threads as the threads rotate.

[0043] During the formation of the mixture, the rubber mixture is introduced into the device 100 through the inlet orifice. As the roller continues to rotate, roller 112 will move in the circumferential direction (see...). Figure 2 Arrow B) indicates that the mixture is fed into the gap between the outer surface 112a of the roller and the inner surface of the dome wall. The rubber mixture adjacent to the outer surface 112a of the roller 112 is scraped by the edge of the stripes 112Ra as it moves forward. As the mixture passes through the stripes 112Ra, shear energy (corresponding to the height of the stripes and the rotational speed of the roller 112) is imparted to the mixture, thereby increasing its temperature and breaking up larger particles or clumps in the mixture. This maintains the continuity of the mixture's flow, resulting in uniform temperature and a homogeneous mixture.

[0044] The rubber compound continues forward until it reaches the extrusion orifice, where it is plasticized and carried away by a plate, subsequently exiting the device 100 as a thin strip. A "thin strip" is referred to as a strip with a thickness of less than 5 mm (by now, the plasticization of the rubber compound by the device is necessarily limited by the nature of the tooling). In some embodiments of the device 100, this thickness is approximately 0.3 mm at the outlet of the device 100. Depending on the properties of the rubber compound and the form in which it is introduced into the device inlet orifice (e.g., using a compound that has been processed prior to introduction), thicker strips can be produced.

[0045] Any potential particles generated during the formation of the mixture are removed from the thin strip (which exits from the device 100) by the grooves 112R in the roller 112. All materials can be processed periodically and moderately to produce a very uniform final product that can be placed directly on a forming drum or template.

[0046] It should be understood that device 100 can be arranged at the exit of at least one extruder to guide the mixture exiting the extruder toward the inlet orifice of the device. It should also be understood that the device can be incorporated into a production line having an extruder for extruding multiple rubber compounds and at least two devices 100 arranged downstream to allow multiple products (in other words, thin strips) to be sequentially placed on forming drums. In one embodiment of the production line incorporated with device 100, the mixture can pass between rollers of a roller-die system arranged just downstream of the extruder and upstream of device 100. In this embodiment, the rotation of the rollers can be managed by the amount of mixture supplied (e.g., detected by a proximity sensor, pressure sensor, or equivalent device) to form a continuous cord layer of predetermined thickness and width.

[0047] In all embodiments of device 100, a monitoring system may be installed. At least a portion of the monitoring system may be located in a portable device, such as a mobile network device (e.g., a mobile phone, a laptop, a camera, one or more portable devices connected to a network (including “augmented reality” and / or “virtual reality” devices, portable clothing connected to a network, and / or any combination and / or any equivalent)).

[0048] In embodiments of the invention, device 100 (and / or facilities or tire production lines incorporated into device 100) may receive voice commands or other audio data (e.g., indicating the start or stop of the compound forming process). The request may include a request for the current state of the rubber compound forming process. The resulting response may be represented in an auditory, visual, tactile manner (e.g., via a tactile interface) and / or in a virtual and / or augmented manner.

[0049] In one embodiment, the blending process performed by the device 100 of the present invention may include a step of training the device 100 (or training a facility or tire production line incorporated into the device 100) to identify values ​​representing thin strips (e.g., values ​​relative to the length, width, and thickness of detected and removed particles) and comparing them to expected values. This step may include a step of training the device 100 to identify a lack of equivalence between the compared values. Each training step may include a classification generated by a self-learning device. This classification may include, but is not limited to, parameters of the selected rubber blend formulation, the duration of the blending process, and expected values ​​during the ongoing tire production cycle. The obtained data may be fed into one or more neural networks that manage the device 100 and / or one or more facilities or production lines incorporated into the device 100.

[0050] The terms "at least one" and "one or more" are used interchangeably. The given range between "a" and "b" includes the values ​​"a" and "b".

[0051] Although specific embodiments of the disclosed device have been shown and described, it should be understood that various changes, additions, and modifications may be made without departing from the spirit or scope of this specification. Therefore, the scope of the invention described should not be limited except as set forth in the appended claims.

Claims

1. An extrusion apparatus (100) for forming a rubber-based product in the form of a thin strip, the apparatus comprising a rotating roller (112), an inlet orifice allowing flow of the rubber mixture, and an arch covering at least a portion of the outer surface (112a) of the rotating roller (112) circumferentially, the arch having a wall having projecting threads on the inner surface of the wall oriented toward the rotating roller (112), thereby defining a chamber for plasticizing the rubber mixture with the surface of the rotating roller, pushing the rubber mixture from the inlet orifice toward the extrusion orifice in a gap defining the product profile, the gap being defined by the wall of the arch and the outer surface of the rotating roller, characterized in that: A continuous spiral groove (112R) is formed on the outer surface (112a) of the rotating roller (112). The groove includes a plurality of stripes (112Ra) arranged one after another along the direction of movement of the rubber compound, and the stripes (112Ra) are spaced apart from each other to produce a thread with a predetermined pitch. The rotating roller and the dome are assembled such that the crests of the thread produced by the continuous helix and the crests of the protruding threads on the dome are tangent to each other.

2. The apparatus (100) according to claim 1 further includes an extrusion plate that adjustably defines an extrusion orifice with the outer surface (112a) of the rotating roller (112).

3. The device (100) according to claim 2, wherein, Each stripe (112Ra) has a cross-section with a predetermined geometry, a circle at the bottom of each stripe, and a pointed edge.

4. The device (100) according to claim 3, wherein, The angle between the edge of the stripe and the outer surface of the rotating roller is less than or equal to 90°.

5. The device (100) according to claim 3 or claim 4, wherein, The stripe (112Ra) has a triangular cross-section.

6. The device (100) according to claim 1, wherein, The protruding thread includes: - At least two axial threads that extend substantially axially from the wall of the dome toward the outer surface (112a) of the rotating roller (112); and - One or more threads oriented in different directions from the axial thread, selected from helical threads, converging threads, or diverging threads.

7. The device (100) according to claim 1, wherein, The gaps defining the product profile are limited to a product thickness of less than 5 millimeters.

8. The device (100) according to claim 1, wherein, The dome can be pivotally mounted around a rotation axis supported by a support element (120) of a rotating roller (112).

9. A method for forming a rubber compound produced by the apparatus (100) according to any one of claims 1 to 8, comprising the following steps: - The step of introducing the rubber mixture into the device (100) through the inlet hole; - The step of conveying the rubber mixture in a circumferential direction, which is performed by the rotating roller (112) as the rotating roller (112) rotates; as well as - The step of advancing the rubber compound to the extrusion orifice of the device and then exiting the device (100) in the form of a thin strip.

10. A tire production line comprising at least one device (100) according to any one of claims 1 to 8, said device (100) being arranged downstream of at least one extruder for extruding a rubber compound.

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