Bead core coating device

Abstract

To provide a bead core coating device capable of enlarging drum diameter of a rotary drum in a device for pasting a rubber sheet extruded from an extruder onto a bead core via a rotary drum.SOLUTION: A bead core coating device comprises: an extruder; a rotary drum; a covering device for rotatably supporting a bead core so that an outer circumferential surface of the rotary drum and an inner circumferential surface of the bead core are brought into close contact with each other; and a controller for controlling the extruder, the rotary drum, and the covering device so that a rubber sheet extruded from the extruder is wound from its leading end around the outer circumferential surface of the rotary drum, a portion of the rubber sheet in a width direction on the outer circumferential surface of the rotary drum is pasted from the leading end onto the inner circumferential surface of the rotating bead core, and a remaining portion of the rubber sheet in the width direction pasted on the inner circumferential surface of the bead core is wound along a cross-sectional shape of the bead core using the covering device. A rotation axis of the rotary drum is arranged on the same plane as a rotation axis of the bead core to be inclined with respect to the rotation axis of the bead core.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a bead core coating device. [Background technology]

[0002] Generally, the bead of a pneumatic tire has an annular bead core formed by rubber-coating a bundle of steel wires or the like. The surface of this bead core may be covered with a thin rubber sheet to integrate the steel wires or the like. This rubber sheet is sometimes called a cover rubber or a bead cover rubber.

[0003] Patent Document 1 below discloses a bead core coating method including the steps of: winding a rubber sheet extruded from an extruder around the outer peripheral surface of a rotating drum, starting from the tip; attaching a widthwise portion of the rubber sheet on the outer peripheral surface of the rotating drum from the tip to the outer surface of a rotating bead core before the rubber sheet is wrapped around the entire outer peripheral surface of the rotating drum; and winding the remaining widthwise portion of the rubber sheet attached to the outer surface of the bead core along the cross-sectional shape of the bead core. That is, in the bead core coating method of Patent Document 1, the rubber sheet extruded from the extruder is first wound around the outer peripheral surface of a rotating drum, and then the rubber sheet on the rotating drum is attached to the outer surface of the bead core. This prevents dimensional changes in the rubber sheet extruded from the extruder and enables the bead core to be coated with the rubber sheet with high precision.

[0004] In the bead core coating method of Patent Document 1, for example, it is desirable to arrange the extruder and the rotating drum on the inner periphery of the bead core and to make the diameter of the rotating drum as large as possible in order to increase the circumferential contact area between the rubber sheet on the rotating drum and the bead core and make it easier to attach the rubber sheet to the bead core. However, with a configuration in which the extruder and the rotating drum are arranged on the inner periphery of the bead core, the size of the inner diameter of the bead core is limited, making it difficult to increase the diameter of the rotating drum. Therefore, in order to increase the diameter of the rotating drum, it was necessary to improve the arrangement of the rotating drum and the bead core. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-51670 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is to provide a bead core coating device that can increase the drum diameter of a rotating drum in an apparatus that applies a rubber sheet extruded from an extruder to a bead core via a rotating drum. [Means for solving the problem]

[0007] The bead core covering device of the present disclosure is a bead core covering device that covers an annular bead core with a strip-shaped rubber sheet, an extruder for extruding the rubber sheet; a rotating drum around which the rubber sheet extruded from the extruder is wound; a covering device that rotatably supports the bead core at a position downstream of the extruder in the rotation direction of the rotating drum so that the outer peripheral surface of the rotating drum and the inner peripheral surface of the bead core are close to each other; a control unit that controls the extruder, the rotating drum, and the covering device so that the rubber sheet extruded from the extruder is wound around the outer peripheral surface of the rotating drum from its tip, and before the rubber sheet is wound around the entire outer peripheral surface of the rotating drum, a part of the rubber sheet in the width direction on the outer peripheral surface of the rotating drum is attached to the inner peripheral surface of the bead core that is rotating from the tip, and the remaining part of the rubber sheet in the width direction attached to the inner peripheral surface of the bead core is wound along the cross-sectional shape of the bead core by the covering device, The rotation axis of the rotary drum is disposed on the same plane as the rotation axis of the bead core, but is inclined with respect to the rotation axis of the bead core. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a front view schematically illustrating an example of the configuration of a bead core covering device. [Figure 2] A cross-sectional view of the bead core coating device shown in FIG. 1 along line II-II. [Figure 3] Cross section of a bead core DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, one embodiment of the bead core coating device will be described with reference to the drawings. Note that in each drawing, the dimensional ratios of the drawings do not necessarily match the actual dimensional ratios, and the dimensional ratios between the drawings do not necessarily match.

[0010] The bead core covering device of this embodiment is for covering an annular bead core with a long, strip-shaped rubber sheet having a predetermined width. Note that, although the bead core in this embodiment is described as having a hexagonal cross section, the cross section of the bead core is not limited to this, and may be rectangular, round, or the like.

[0011] Fig. 1 is a front view schematically showing an example of the configuration of a bead core coating apparatus 1. Fig. 2 is a cross-sectional view of the bead core coating apparatus 1 of Fig. 1 taken along line II-II. The bead core coating apparatus 1 includes an extruder 2, a rotating drum 3, a covering device 4, and a control unit (not shown) that controls the extruder 2, the rotating drum 3, and the covering device 4. In the cross-sectional view of Fig. 2, everything except the rotating drum 3, the rubber sheet S, and the bead core 8 is drawn in plan view.

[0012] 1 and 2, in the following description, the direction parallel to the central axis of the annular bead core 8 is referred to as the X direction, the radial direction of the bead core 8 is referred to as the Y direction, and the direction perpendicular to the X direction and the Y direction is referred to as the Z direction. When expressing a direction, if a distinction is made between positive and negative directions, the direction is described with a positive or negative sign, such as "+X direction" and "-X direction," and when expressing a direction without distinguishing between positive and negative directions, the direction is simply described as "X direction."

[0013] The extruder 2 has a cylindrical barrel 2a, a hopper 2b connected to the supply port of the barrel 2a, a screw (not shown) that mixes the rubber in the barrel 2a and sends it out to the tip end, and a screw motor 2c that rotates the screw. The operation of the screw motor 2c is controlled by a control unit.

[0014] A gear pump 20 is connected to the tip end of the extruder 2 in the extrusion direction, and the tip end of the gear pump 20 is connected to a nozzle 21. The rubber material kneaded by the extruder 2 is supplied to the gear pump 20. The gear pump 20 has an end face 20b, and a discharge port (not shown) is formed in the end face 20b. The gear pump 20 discharges the rubber supplied from the extruder 2 from the discharge port and supplies a fixed amount of rubber to the nozzle 21. A rubber sheet S is extruded from the nozzle 21 at a predetermined extrusion amount.

[0015] The gear pump 20 has a pair of gears 20a and functions to feed rubber toward the nozzle 21. The pair of gears 20a are each rotated by a gear motor (not shown), and the operation of the gear motor is controlled by a control unit. By controlling the rotation speed of the gear motor and the rotation speed of the screw motor 2c in conjunction with each other by the control unit, the extrusion amount of the rubber sheet S extruded from the nozzle 21 can be controlled.

[0016] In this embodiment, an example is shown in which a so-called external gear pump is used, in which the gear pump 20 is connected to the tip side of the extruder 2 in the extrusion direction. However, instead of this, an extruder with a built-in gear pump, in which a gear pump is built into the extruder, may be used. In the present disclosure, an extruder with a built-in gear pump is more preferable than an extruder connected to an external gear pump because it is easier to control the extrusion rate and does not require a gear motor, making the tip of the extruder more compact.

[0017] The extruder 2, gear pump 20, and nozzle 21 are configured to be movable as a unit back and forth in the extrusion direction by a front-rear drive device (not shown). The extruder 2 moves closer to the rotating drum 3 by moving forward, and moves away from the rotating drum 3 by moving backward. The operation of the front-rear drive device is also controlled by the control unit.

[0018] The rotating drum 3 is configured to be rotatable around a rotation axis 3r by a servo motor 30. The operation of the servo motor 30 is controlled by a control unit. A rubber sheet S extruded through a nozzle 21 is supplied to the outer peripheral surface 3a of the rotating drum 3, and by rotating the rotating drum 3 in the R1 direction with the rubber sheet S attached, the rubber sheet S can be wound around the circumferential direction. The outer peripheral surface 3a of the rotating drum 3 is made of metal. The outer diameter of the rotating drum 3 (hereinafter also referred to as the drum diameter) is, for example, 200 to 400 mm.

[0019] The rotating drum 3 preferably includes a cooling mechanism for cooling the outer peripheral surface 3a or a heating mechanism for heating it (neither is shown). The cooling mechanism or heating mechanism may be, for example, a mechanism for circulating cold water or hot water inside the rotating drum 3. Furthermore, the outer peripheral surface 3a of the rotating drum 3 may be subjected to a surface treatment or made of a material that makes it easy to peel off the attached rubber sheet S.

[0020] The covering device 4 rotatably supports the bead cores 8 at a position downstream of the extruder 2 in the rotation direction R1 of the rotating drum 3 so that the outer peripheral surface 3a of the rotating drum 3 and the inner peripheral surface of the bead core 8 are close to each other. The bead cores 8 rotate around a rotation axis 4r. The drum diameter of the rotating drum 3 is smaller than the inner diameter of the bead cores 8, and the rotating drum 3 is disposed on the inner peripheral side of the bead cores 8 supported by the covering device 4 in a front view. The drum diameter of the rotating drum 3 is preferably 0.3 times or more, and more preferably 0.4 times or more, the inner diameter of the bead cores 8. By making the drum diameter of the rotating drum 3 0.3 times or more the inner diameter of the bead cores 8, the circumferential contact area between the rubber sheet S on the rotating drum 3 and the bead cores 8 is increased, making it easier to attach the rubber sheet S to the bead cores 8. In theory, the rubber sheet S and the bead core 8 are in line contact because the drum diameter of the rotating drum 3 and the inner diameter of the bead core 8 are different. However, in reality, the rubber sheet S is pressed and deformed when attached, so they may be in surface contact. By bringing the drum diameter of the rotating drum 3 closer to the inner diameter of the bead core 8, the circumferential contact length between the rubber sheet S and the bead core 8 increases, and therefore the circumferential contact area between the rubber sheet S and the bead core 8 increases. Although not particularly limited, the circumferential contact length between the rubber sheet S and the bead core 8 is approximately 2 to 5 mm.

[0021] The covering device 4 is used to wrap the rubber sheet S attached to the inner peripheral surface of the bead core 8 along the cross-sectional shape of the bead core 8. The covering device 4 can rotate the supported bead core 8 in the R2 direction. The bead core 8 rotates following the rotation of the rotating drum 3.

[0022] 3 shows a cross-sectional view of the bead core 8. The bead core 8 has a hexagonal cross-section and has an inner peripheral surface 8a, an outer peripheral surface 8d, a pair of lower surfaces 8b and 8f on the inner peripheral side, and a pair of upper surfaces 8c and 8e on the outer peripheral side.

[0023] The inner circumferential surface 8a is inclined with respect to the rotation axis 4r of the bead core 8. The inclination angle θ1 of the inner circumferential surface 8a with respect to the rotation axis 4r of the bead core 8 is 15 to 20 degrees. In the present disclosure, the inner circumferential surface 8a of the bead core 8 refers to the surface of the outer surfaces of the bead core 8 (outer surfaces 8a to 8f in this embodiment) that has the smallest inclination angle with respect to the rotation axis 4r of the bead core 8.

[0024] The inner diameter of the bead core 8 is, for example, 400 to 650 mm. The inner diameter of the bead core 8 is the diameter of the inner circumferential surface 8a at a position closest to the rotation axis 4r, and in the bead core 8 shown in Fig. 3, it is the diameter of a circle formed by the intersection line between the inner circumferential surface 8a and the lower surface 8f.

[0025] A rubber sheet S is wrapped around the outer surface of the bead core 8. The central portion in the width direction of the strip-shaped rubber sheet S is first attached to the inner peripheral surface 8a of the bead core 8, and then one side in the width direction is attached to the lower side surface 8b, the upper side surface 8c, and the outer peripheral surface 8d, in that order, and the other side in the width direction is attached to the lower side surface 8f, the upper side surface 8e, and the outer peripheral surface 8d, in that order.

[0026] The covering device 4 includes a pressure roller 41. The pressure roller 41 is disposed in a position facing the rotating drum 3 with a part of the bead core 8 sandwiched therebetween. As shown in FIG. 2, the pressure roller 41 is a so-called flanged roller that has a roller body 411 and a flange 412 provided at the axial end of the roller body 411.

[0027] The rotation axis 41A of the pressure roller 41 is approximately parallel to the rotation axis 3r of the rotating drum 3, and the pressure roller 41 rotates while the outer peripheral surface of the roller body 411 is in contact with the outer peripheral surface 8d of the bead core 8. The pressure roller 41 is also configured to be movable back and forth toward the bead core 8. This allows the pressure roller 41 to press against the outer peripheral surface 8d of the bead core 8 when bonding the central portion in the width direction of the rubber sheet S on the outer peripheral surface 3a of the rotating drum 3 to the inner peripheral surface 8a of the rotating bead core 8. The pressure roller 41 is a driven roller that rotates following the rotation of the bead core 8.

[0028] When the rubber sheet S is attached to the inner peripheral surface 8a, the bead core 8 is pressed by the rotating drum 3 and a force in the +X direction is applied. The pressure roller 41 is provided with a flange 412, so that the movement of the bead core 8 in the +X direction can be restricted.

[0029] The covering device 4 includes a plurality of rollers 42 to 46 for wrapping the rubber sheet S around the cross-sectional shape of the bead core 8. The rollers 42 to 46 each have the following functions, although they are not particularly limited. The roller 42 attaches the rubber sheet S to, for example, the lower side surfaces 8b and 8f. The roller 44 attaches the rubber sheet S to, for example, the upper side surface 8c and the outer peripheral surface 8d. The roller 45 attaches the rubber sheet S to, for example, the upper side surface 8e and the outer peripheral surface 8d. The roller 43 bends both widthwise ends of the rubber sheet S toward the bead core 8 so that the rollers 44 and 45 can easily attach the rubber sheet S to the upper side surfaces 8c and 8e and the outer peripheral surface 8d. The roller 46 presses both widthwise ends of the rubber sheet S against the outer peripheral surface 8d of the bead core 8. Auxiliary rollers are disposed at positions opposite the rollers 42, 44, 45, and 46 across the bead core 8. The covering device 4 also includes a plurality of guide rollers 47 that prevent the rotating bead core 8 from meandering.

[0030] Next, the positional relationship between the rotating drum 3 and the bead core 8 will be described. As shown in FIG. 1, the rotation axis 3r of the rotating drum 3 is disposed on the same XY plane as the rotation axis 4r of the bead core 8. Furthermore, as shown in FIG. 2, the rotation axis 3r of the rotating drum 3 is disposed at an angle with respect to the rotation axis 4r of the bead core 8. This reduces the overlap between the rotating drum 3 and the bead core 8 when viewed in the Z direction, allowing the drum diameter of the rotating drum 3 to be increased so that it approaches the inner diameter of the bead core 8. Increasing the drum diameter of the rotating drum 3 increases the circumferential contact area between the rubber sheet S on the rotating drum 3 and the bead core 8, making it easier to attach the rubber sheet S to the bead core 8. Furthermore, increasing the drum diameter of the rotating drum 3 makes it easier to obtain the cooling effect of the cooling mechanism on the outer peripheral surface 3a, preventing problems such as the rubber sheet S not peeling off from the outer peripheral surface 3a. Furthermore, by increasing the drum diameter of the rotating drum 3, the curvature of the outer peripheral surface 3a can be reduced, making it easier to adjust the thickness of the rubber sheet S formed in the gap between the mouthpiece 21 and the outer peripheral surface 3a.

[0031] The inclination angle θ2 of the rotation axis 3r of the rotating drum 3 relative to the rotation axis 4r of the bead core 8 is 15±10 degrees, and preferably 15±5 degrees. The inclination angle θ2 is an angle in a plane including the rotation axis 3r of the rotating drum 3 and the rotation axis 4r of the bead core 8 (the XY plane in this embodiment, as described above). If the inclination angle θ2 is less than 5 degrees, the overlap between the rotating drum 3 and the bead core 8 becomes large when viewed in the Z direction, making it difficult to increase the drum diameter of the rotating drum 3. If the inclination angle θ2 is greater than 25 degrees, the difference with the inclination angle θ1 becomes large, making it difficult to properly attach the rubber sheet S to the inner circumferential surface 8a of the bead core 8.

[0032] The inclination angle θ2 is preferably within a range of ±5 degrees relative to the inclination angle θ1, more preferably within a range of ±2 degrees, and particularly preferably within a range of ±0 degrees. That is, it is particularly preferable that the inclination angle θ2 coincide with the inclination angle θ1, for example, 15 to 20 degrees. If the inclination angle θ2 exceeds a range of ±5 degrees relative to the inclination angle θ1, it becomes difficult to attach the rubber sheet S on the rotating drum 3 to the inner circumferential surface 8a of the bead core 8.

[0033] Next, the positional relationship between the extruder 2 and the rotating drum 3 will be described. As shown in FIG. 1, the discharge port formed in the end face 20b of the gear pump 20 is arranged on the same XY plane as the rotation axis 3r of the rotating drum 3. In the XY plane including the discharge port of the gear pump 20 and the rotation axis 3r of the rotating drum 3, the end face 20b of the gear pump 20 is arranged at an angle with respect to the outer peripheral surface 3a of the rotating drum 3. The angle θ3 formed between the end face 20b of the gear pump 20 and the outer peripheral surface 3a of the rotating drum 3 is 30 degrees or less, and preferably 20 degrees or less. By setting the angle θ3 to 30 degrees or less, the curvature of the rubber flow path formed inside the die 21 can be reduced, thereby reducing the difference in flow velocity in the opening width direction of the die 21.

[0034] As described above, the bead core covering device 1 according to this embodiment is a bead core covering device 1 that covers annular bead cores 8 with a strip-shaped rubber sheet S, and includes the extruder 2 that extrudes the rubber sheet S, the rotary drum 3 around which the rubber sheet S extruded from the extruder 2 is wound, the covering device 4 that rotatably supports the bead cores 8 at a position downstream of the extruder 2 in the rotation direction R1 of the rotary drum 3 so that the outer peripheral surface 3a of the rotary drum 3 and the inner peripheral surface 8a of the bead cores 8 are close to each other, and the rubber sheet S extruded from the extruder 2 is wound around the outer peripheral surface 3a of the rotary drum 3 from the tip, so that the rubber sheet S is not rotated. and a control unit that controls the extruder 2, the rotating drum 3, and the covering device 4 so that before the rubber sheet S is wrapped around the entire outer peripheral surface 3a of the rotating drum 3, a portion of the width direction of the rubber sheet S on the outer peripheral surface 3a of the rotating drum 3 is attached to the inner peripheral surface 8a of the bead core 8 that rotates from the tip, and the remaining portion of the width direction of the rubber sheet S attached to the inner peripheral surface 8a of the bead core 8 is wrapped along the cross-sectional shape of the bead core 8 by the covering device 4, and the rotation axis 3r of the rotating drum 3 is arranged on the same plane as the rotation axis 4r of the bead core 8 and inclined relative to the rotation axis 4r of the bead core 8.

[0035] According to this configuration, the overlap between the rotating drum 3 and the bead core 8 can be reduced when viewed in the Z direction, so that the drum diameter of the rotating drum 3 can be increased so as to approach the inner diameter of the bead core 8.

[0036] In addition, in the bead core coating device 1 according to this embodiment, the rotation axis 3r of the rotary drum 3 is inclined with respect to the rotation axis 4r of the bead core 8 at an angle θ2 of 15±10 degrees.

[0037] This configuration makes it possible to increase the drum diameter of the rotating drum 3. Furthermore, even in the case of a bead core 8 whose inner circumferential surface 8a is inclined with respect to the rotation axis 4r of the bead core 8 as shown in Fig. 3, the rubber sheet S can be properly attached to the inner circumferential surface 8a of the bead core 8.

[0038] Furthermore, the bead core coating device 1 according to this embodiment is equipped with a gear pump 20 that is connected to the tip end of the extruder 2 in the extrusion direction and has an outlet formed on its end face 20b for discharging the rubber supplied from the extruder 2, and in a plane including the outlet and the rotation axis 3r of the rotating drum 3, the angle θ3 formed between the end face 20b of the gear pump 20 and the outer peripheral surface 3a of the rotating drum 3 is 30 degrees or less.

[0039] According to this configuration, the curvature of the rubber flow path formed inside the nozzle 21 can be reduced, so that the difference in flow velocity in the opening width direction of the nozzle 21 can be reduced.

[0040] In the bead core coating device 1 according to this embodiment, the drum diameter of the rotary drum 3 is 0.3 times the inner diameter of the bead core 8 or more.

[0041] According to this configuration, the contact area in the circumferential direction between the rubber sheet S on the rotary drum 3 and the bead core 8 is increased, making it easier to attach the rubber sheet S to the bead core 8.

[0042] In addition, in the bead core covering device 1 of this embodiment, the covering device 4 is equipped with a pressure roller 41 that faces the rotating drum 3 across the bead core 8 and presses the bead core 8, and the pressure roller 41 has a roller body 411 and a flange 412 provided at the axial end of the roller body 411.

[0043] According to this configuration, when the rubber sheet S is attached to the inner peripheral surface 8a, the bead core 8 can be prevented from being pushed by the rotary drum 3 and moving in the axial direction.

[0044] Although the embodiments of the present disclosure have been described above with reference to the drawings, the specific configurations should not be considered to be limited to these embodiments. The scope of the present disclosure is defined not only by the description of the above embodiments but also by the claims, and further includes all modifications within the meaning and scope of the claims.

[0045] The structures employed in the above-described embodiments can be employed in any other embodiment. The specific configurations of the components are not limited to the above-described embodiments, and various modifications are possible within the scope of the present disclosure.

[0046] (1) In the bead core coating device 1 according to the above embodiment, the rotation axis 3r of the rotating drum 3 is inclined at an angle θ2 of 15±10 degrees relative to the rotation axis 4r of the bead core 8. However, the bead core coating device 1 is not limited to this configuration. For example, if the inclination angle θ1 of the inner circumferential surface 8a of the bead core 8 relative to the rotation axis 4r is smaller than 15 degrees, it may be preferable to make the inclination angle θ2 smaller than 15 degrees.

[0047] (2) The bead core coating device 1 according to the above embodiment includes a gear pump 20 connected to the extruder 2 at the tip end in the extrusion direction. The gear pump 20 has an outlet formed on its end face 20b through which rubber supplied from the extruder 2 is discharged. In a plane including the outlet and the rotation axis 3r of the rotating drum 3, the angle θ3 between the end face 20b of the gear pump 20 and the outer peripheral surface 3a of the rotating drum 3 is 30 degrees or less. However, the bead core coating device 1 is not limited to this configuration. For example, if the die 21 is equipped with a mechanism capable of reducing the flow velocity difference in the opening width direction, the angle θ3 can be made greater than 30 degrees, thereby enabling the drum diameter of the rotating drum 3 to be further increased. Furthermore, in the above embodiment, the end face 20b of the gear pump 20 is inclined with respect to the outer peripheral surface 3a of the rotating drum 3. However, this is not a limitation. The end face 20b of the gear pump 20 may be parallel to the outer peripheral surface 3a of the rotating drum 3.

[0048] (3) In the bead core coating device 1 according to the above embodiment, the drum diameter of the rotating drum 3 is 0.3 times or more the inner diameter of the bead core 8. However, the bead core coating device 1 is not limited to this configuration. For example, if the inner diameter of the bead core 8 is sufficiently large, even if the drum diameter of the rotating drum 3 is made smaller than 0.3 times the inner diameter of the bead core 8, an appropriate circumferential contact area can be ensured between the rubber sheet S on the rotating drum 3 and the bead core 8.

[0049] (4) In the bead core coating device 1 according to the above embodiment, the position where the tip of the nozzle 21 of the extruder 2 is closest to the outer peripheral surface 3a of the rotating drum 3 and the position where the inner peripheral surface 8a of the bead core 8 is closest to the outer peripheral surface 3a of the rotating drum 3 are offset by 180° in the rotation direction R1 of the rotating drum 3, but this is not limited to this and may be offset by 90° or 270°. [Explanation of symbols]

[0050] 1...Bead core covering device, 2...Extruder, 3...Rotating drum, 3a...Outer peripheral surface of rotating drum, 3r...Rotating drum shaft, 4...Covering device, 4r...Rotating shaft of bead core, 8...Bead core, 8a...Inner peripheral surface of bead core, 8b...Lower surface of bead core, 8c...Upper surface of bead core, 8d...Outer peripheral surface of bead core, 8e...Upper surface of bead core, 8f...Lower surface of bead core, 20...Gear pump, 20a...Gear, 20b...Gear pump End face, 21... nozzle, 41... pressure roller, 41A... pressure roller rotation axis, 42 to 46... roller, 47... guide roller, 411... roller body, 412... flange, R1... rotation direction of rotating drum, R2... rotation direction of bead core, S... rubber sheet, θ1... inclination angle of inner circumferential surface of bead core relative to rotation axis, θ2... inclination angle of rotating drum rotation axis relative to rotation axis of bead core, θ3... angle between end face of gear pump and outer circumferential surface of rotating drum

Claims

1. A bead core covering device that covers an annular bead core with a band-shaped rubber sheet, an extruder for extruding the rubber sheet; a rotating drum around which the rubber sheet extruded from the extruder is wound; a covering device that rotatably supports the bead core at a position downstream of the extruder in the rotation direction of the rotating drum so that the outer peripheral surface of the rotating drum and the inner peripheral surface of the bead core are close to each other; a control unit that controls the extruder, the rotating drum, and the covering device so that the rubber sheet extruded from the extruder is wound around the outer peripheral surface of the rotating drum from its tip, and before the rubber sheet is wound around the entire outer peripheral surface of the rotating drum, a part of the rubber sheet in the width direction on the outer peripheral surface of the rotating drum is attached to the inner peripheral surface of the bead core that is rotating from the tip, and the remaining part of the rubber sheet in the width direction attached to the inner peripheral surface of the bead core is wound along the cross-sectional shape of the bead core by the covering device, A bead core coating device, wherein the rotation axis of the rotating drum is disposed on the same plane as the rotation axis of the bead core and is inclined with respect to the rotation axis of the bead core.

2. 2. The bead core coating device according to claim 1, wherein the rotation axis of the rotary drum is inclined at an angle of 15±10 degrees with respect to the rotation axis of the bead core.

3. a gear pump connected to a tip end of the extruder in the extrusion direction, the gear pump having a discharge port formed on an end surface thereof for discharging the rubber supplied from the extruder; 3. The bead core coating device according to claim 1, wherein an angle formed between an end face of the gear pump and an outer peripheral surface of the rotating drum is 30 degrees or less in a plane including the discharge port and the rotation axis of the rotating drum.

4. 4. The bead core coating device according to claim 1, wherein the drum diameter of the rotary drum is 0.3 times or more the inner diameter of the bead core.

5. the covering device includes a pressure roller that faces the rotating drum across the bead core and presses the bead core, 5. The bead core covering device according to claim 1, wherein the pressure roller has a roller body and a flange provided at an axial end of the roller body.

Images