Bead core covering device

Abstract

The present invention provides a bead core covering device, which includes an extruder, a rotary drum, a covering device, and a control unit. The covering device supports the bead core in a rotatable manner such that the outer peripheral surface of the rotary drum approaches the inner peripheral surface of the bead core. The control unit controls the extruder, the rotary drum, and the covering device so that the rubber sheet extruded from the extruder is wound around the outer peripheral surface of the rotary drum from the front end, a part in the width direction of the rubber sheet located on the outer peripheral surface of the rotary drum is pasted to the inner peripheral surface of the rotating bead core from the front end, and the remaining part in the width direction of the rubber sheet pasted 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 inclinedly with respect to the rotation axis of the bead core in the same plane as the rotation axis of the bead core.

Description

Technical Field

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

[0002] Generally, in the bead of a pneumatic tire, there is provided an annular bead core formed by rubber-coating a bundle such as steel wire. Sometimes, the surface of the bead core is coated with a thin rubber sheet in order to integrate the steel wire or the like. This rubber sheet is sometimes also referred to as cover rubber or bead cover rubber.

[0003] In Patent Document 1 below, a bead core coating method is disclosed, which includes: a step of winding a rubber sheet extruded from an extruder around the outer peripheral surface of a rotating drum from the front end; a step of sticking a part in the width direction of the rubber sheet located on the outer peripheral surface of the rotating drum to the outer surface of a rotating bead core before the rubber sheet is wound around the entire outer peripheral surface of the rotating drum; and a step of winding the remaining part in the width direction of the rubber sheet stuck 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, after temporarily winding the rubber sheet extruded from the extruder around the outer peripheral surface of the rotating drum, the rubber sheet on the rotating drum is stuck to the outer surface of the bead core. Thereby, it is possible to prevent the size of the rubber sheet extruded from the extruder from changing, and thus it is possible to coat the bead core with the rubber sheet with high precision.

[0004] However, in the bead core coating method of Patent Document 1, for example, from the viewpoint of increasing the circumferential contact area between the rubber sheet on the rotating drum and the bead core to make it easier to stick the rubber sheet to the bead core, it is desired to provide an extruder and a rotating drum on the inner peripheral side of the bead core and to increase the drum diameter of the rotating drum as much as possible. However, in a structure in which an extruder and a rotating drum are arranged on the inner peripheral side of the bead core, since the inner diameter size of the bead core is restricted, it is difficult to increase the drum diameter of the rotating drum. Therefore, in order to increase the drum diameter of the rotating drum, it is necessary to improve the arrangement of the rotating drum and the bead core.

[0005] FB223624JP-I

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2019-51670 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] 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 a device that sticks a rubber sheet extruded from an extruder to a bead core via the rotating drum.

[0011] Technical solution for solving the problem

[0012] 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, and includes:

[0013] An extruder that extrudes the rubber sheet;

[0014] A rotating drum that winds the rubber sheet extruded from the extruder;

[0015] A covering device that supports the bead core rotatably in such a manner that the outer peripheral surface of the rotating drum approaches the inner peripheral surface of the bead core at a position downstream of the extruder in the rotation direction of the rotating drum; and

[0016] 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 from the front end around the outer peripheral surface of the rotating drum, and before the rubber sheet is wound around the entire circumference of the outer peripheral surface of the rotating drum, a part in the width direction of the rubber sheet located on the outer peripheral surface of the rotating drum is pasted from the front end to the inner peripheral surface of the rotating bead core, and the remaining part in the width direction of the rubber sheet pasted to the inner peripheral surface of the bead core is wound along the cross-sectional shape of the bead core by the covering device,

[0017] The rotation axis of the rotating drum is inclined with respect to the rotation axis of the bead core in the same plane as the rotation axis of the bead core. Description of the drawings

[0018] Figure 1 is a front view schematically showing an example of the structure of the bead core covering device.

[0019] Figure 2 is Figure 1 a cross-sectional view taken along line II-II of the bead core covering device of

[0020] Figure 3 is a cross-sectional view of the bead core. Detailed implementation mode

[0021] Hereinafter, an embodiment of the bead core covering device will be described with reference to the drawings. In addition, in each figure, the dimensional ratio of the drawing is not necessarily the same as the actual dimensional ratio, and further, the dimensional ratios between the respective drawings are not necessarily the same.

[0022] The bead core covering device of the present embodiment covers an annular bead core with a long strip-shaped rubber sheet having a predetermined width. In addition, the bead core of the present embodiment is described with a hexagonal cross-section, but is not limited thereto, and the cross-sectional shape of the bead core may also be a quadrilateral or a circle, etc.

[0023] Figure 1 is a front view schematically showing an example of the structure of the bead core covering device 1. Figure 2 is Figure 1 a sectional view taken along line II-II of the bead core covering device 1. The bead core covering device 1 includes an extruder 2, a rotary drum 3, a covering device 4, and a control unit (not shown) that controls the extruder 2, the rotary drum 3, and the covering device 4. It should be noted that, in the Figure 2 sectional view, parts other than the rotary drum 3, the rubber sheet S, and the bead core 8 are depicted in a plan view.

[0024] In the following description, as Figure 1 and Figure 2 shown, the direction parallel to the central axis of the annular bead core 8 is set as the X direction, the radial direction of the bead core 8 is set as the Y direction, and the direction orthogonal to the X direction and the Y direction is set as the Z direction. And, when indicating the direction, in the case of distinguishing the positive and negative orientations, it is recorded with the plus or minus sign attached, such as "+X direction", "-X direction", and in the case of indicating the direction without distinguishing the positive and negative orientations, it is only recorded as "X direction".

[0025] 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 kneads rubber in the barrel 2a and sends it out toward the front end side, and a screw electric motor 2c that rotationally drives the screw. The operation of the screw electric motor 2c is controlled by the control unit.

[0026] A gear pump 20 is connected to the front end side in the extrusion direction of the extruder 2, and the front end side of the gear pump 20 is connected to a die 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 die 21. The rubber sheet S is extruded from the die 21 with a specified extrusion amount.

[0027] The gear pump 20 has a pair of gears 20a and has a function of sending out rubber to the die 21. The pair of gears 20a are respectively rotationally driven by gear electric motors (not shown), and the operations of the gear electric motors are controlled by the control unit. By controlling the rotation speeds of the gear electric motors and the screw electric motor 2c to be linked by the control unit, the extrusion amount of the rubber sheet S extruded from the die 21 can be controlled.

[0028] Further, in the present embodiment, an example of using a so-called external gear pump in which a gear pump 20 is connected to the front end side in the extrusion direction of the extruder 2 is shown. However, instead, a gear pump built-in extruder in which a gear pump is built into the extruder may be used. In the present disclosure, compared with the extruder connected with an external gear pump, the gear pump built-in extruder can more easily control the extrusion amount and does not require a gear motor, so the front end portion of the extruder becomes compact, which is more preferable.

[0029] The extruder 2, the gear pump 20, and the die 21 are configured to be able to move back and forth in the extrusion direction as a whole by a front and rear drive device (not shown). The extruder 2 approaches the rotary drum 3 by moving forward and moves away from the rotary drum 3 by moving backward. The operation of the front and rear drive device is also controlled by the control unit.

[0030] The rotary drum 3 is configured to be able to rotate about the rotation axis 3r by a servo motor 30. The operation of the servo motor 30 is controlled by the control unit. The rubber sheet S extruded through the die 21 is supplied to the outer peripheral surface 3a of the rotary drum 3, and the rotary drum 3 is rotationally driven in the R1 direction in a state where the rubber sheet S is adhered, whereby the rubber sheet S can be wound along the circumferential direction. The outer peripheral surface 3a of the rotary drum 3 is made of metal. The outer diameter of the rotary drum 3 (hereinafter, also referred to as the drum diameter) is, for example, 200 to 400 mm.

[0031] The rotary drum 3 preferably includes a cooling mechanism for cooling the outer peripheral surface 3a or a heating mechanism for heating the outer peripheral surface 3a (both not shown). As the cooling mechanism or the heating mechanism, for example, a mechanism in which cooling water or warm water circulates inside the rotary drum 3 is used. In addition, the outer peripheral surface 3a of the rotary drum 3 is subjected to a surface treatment that facilitates peeling of the adhered rubber sheet S or uses the above-mentioned material.

[0032] The covering device 4 supports the bead core 8 rotatably in such a manner that the outer peripheral surface 3a of the rotary drum 3 approaches the inner peripheral surface of the bead core 8 at a position downstream of the extruder 2 in the rotational direction R1 of the rotary drum 3. The bead core 8 rotates about the rotation axis 4r. The drum diameter of the rotary drum 3 is smaller than the inner diameter of the bead core 8, and in a front view, the rotary drum 3 is disposed on the inner peripheral side of the bead core 8 supported by the covering device 4. The drum diameter of the rotary drum 3 is preferably 0.3 times or more, more preferably 0.4 times or more, of the inner diameter of the bead core 8. By making the drum diameter of the rotary drum 3 0.3 times or more of the inner diameter of the bead core 8, the circumferential contact area between the rubber sheet S on the rotary drum 3 and the bead core 8 becomes larger, so that it is easy to stick the rubber sheet S to the bead core 8. And, since the drum diameter of the rotary drum 3 is different from the inner diameter of the bead core 8, the rubber sheet S and the bead core 8 are theoretically in line contact with each other, but in practice, since the rubber sheet S is deformed by being pressed during sticking, they may be in surface contact with each other. By making the drum diameter of the rotary drum 3 close to the inner diameter of the bead core 8, the circumferential contact length between the rubber sheet S and the bead core 8 increases, so that the circumferential contact area between the rubber sheet S and the bead core 8 becomes larger. Although not particularly limited, the circumferential contact length between the rubber sheet S and the bead core 8 is about 2 to 5 mm.

[0033] The covering device 4 is used to wind the rubber sheet S pasted on 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 drivenly by the rotation of the rotary drum 3.

[0034] Figure 3 A cross-sectional view showing the bead core 8. The bead core 8 has a hexagonal cross-sectional shape and has an inner peripheral surface 8a, an outer peripheral surface 8d, a pair of lower side surfaces 8b, 8f on the inner peripheral side, and a pair of upper side surfaces 8c, 8e on the outer peripheral side.

[0035] The inner peripheral surface 8a is inclined with respect to the rotation axis 4r of the bead core 8. The inclination angle θ1 of the inner peripheral surface 8a with respect to the rotation axis 4r of the bead core 8 is 15 to 20 degrees. And, in the present disclosure, the inner peripheral surface 8a of the bead core 8 is the surface with the smallest inclination angle with respect to the rotation axis 4r among the outer surfaces of the bead core 8 (in this embodiment, the outer surfaces 8a to 8f).

[0036] The inner diameter of the bead core 8 is, for example, 400 to 650 mm. And, the inner diameter of the bead core 8 refers to the diameter at the position on the inner peripheral surface 8a closest to the rotation axis 4r, and in the Figure 3 shown bead core 8, it is the diameter of the circle formed by the intersection line of the inner peripheral surface 8a and the lower side surface 8f.

[0037] A rubber sheet S is wound around the outer surface of the bead core 8. The strip-shaped rubber sheet S first adheres the central portion in the width direction to the inner circumferential surface 8a of the bead core 8, and then adheres one side in the width direction to the lower side surface 8b, the upper side surface 8c, and the outer circumferential surface 8d in sequence, and adheres the other side in the width direction to the lower side surface 8f, the upper side surface 8e, and the outer circumferential surface 8d in sequence.

[0038] The covering device 4 includes a pressing roller 41. The pressing roller 41 is disposed at a position opposed to the rotary drum 3 with a part of the bead core 8 interposed therebetween. As Figure 2 shown, the pressing roller 41 is a so-called flanged roller having a roller body 411 and flanges 412 provided at the axial ends of the roller body 411.

[0039] The rotation axis 41A of the pressing roller 41 is substantially parallel to the rotation axis 3r of the rotary drum 3. While the outer circumferential surface of the roller body 411 is in contact with the outer circumferential surface 8d of the bead core 8, the pressing roller 41 rotates. In addition, the pressing roller 41 is configured to be movable back and forth toward the bead core 8. Thus, when adhering the central portion in the width direction of the rubber sheet S located on the outer circumferential surface 3a of the rotary drum 3 to the inner circumferential surface 8a of the rotating bead core 8, the pressing roller 41 can press the outer circumferential surface 8d of the bead core 8. And the pressing roller 41 is a driven roller that rotates driven by the rotation of the bead core 8.

[0040] When the rubber sheet S is adhered to the inner circumferential surface 8a of the bead core 8, the bead core 8 is pressed by the rotary drum 3 and a force in the +X direction is applied. By providing the pressing roller 41 with the flanges 412, the movement of the bead core 8 in the +X direction can be restricted.

[0041] In order to wind the rubber sheet S along the cross-sectional shape of the bead core 8, the covering device 4 includes a plurality of rollers 42 to 46. The plurality of rollers 42 to 46 are not particularly limited and each has the following functions. The roller 42 adheres the rubber sheet S to the lower side surfaces 8b and 8f, for example. The roller 44 adheres the rubber sheet S to the upper side surface 8c and the outer circumferential surface 8d, for example. The roller 45 adheres the rubber sheet S to the upper side surface 8e and the outer circumferential surface 8d, for example. The roller 43 bends the both end portions in the width direction of the rubber sheet S toward the bead core 8 so that the rubber sheet S can be easily adhered to the upper side surfaces 8c and 8e and the outer circumferential surface 8d by the rollers 44 and 45. The roller 46 presses the both end portions in the width direction of the rubber sheet S against the outer circumferential surface 8d of the bead core 8. And auxiliary rollers are respectively disposed at positions opposed to the rollers 42, 44, 45, and 46 with the bead core 8 interposed therebetween. In addition, the covering device 4 includes a plurality of guide rollers 47 for preventing the rotation of the bead core 8 from meandering.

[0042] Next, the positional relationship between the rotary drum 3 and the bead core 8 will be described. As Figure 1 shown, the rotation axis 3r of the rotary drum 3 and the rotation axis 4r of the bead core 8 are arranged in the same XY plane. In addition, as Figure 2As shown, the rotation axis 3r of the rotary drum 3 is inclined with respect to the rotation axis 4r of the bead core 8. Thus, when viewed in the Z direction, the overlap between the rotary drum 3 and the bead core 8 can be reduced, so that the drum diameter of the rotary drum 3 can be increased to be close to the inner diameter of the bead core 8. By increasing the drum diameter of the rotary drum 3, the circumferential contact area between the rubber sheet S on the rotary drum 3 and the bead core 8 becomes larger, so it is easy to stick the rubber sheet S to the bead core 8. In addition, by increasing the drum diameter of the rotary drum 3, it is easy to obtain the cooling effect of the cooling mechanism on the outer peripheral surface 3a, and it is possible to prevent problems such as the rubber sheet S not peeling off from the outer peripheral surface 3a. Moreover, by increasing the drum diameter of the rotary drum 3, the curvature of the outer peripheral surface 3a can be reduced, so it is easy to adjust the thickness of the rubber sheet S formed in the gap between the die 21 and the outer peripheral surface 3a.

[0043] The inclination angle θ2 of the rotation axis 3r of the rotary drum 3 with respect to the rotation axis 4r of the bead core 8 is 15 ± 10 degrees, preferably 15 ± 5 degrees. And, the inclination angle θ2 is an angle on the plane (as described above, in the present embodiment, it is the XY plane) including the rotation axis 3r of the rotary drum 3 and the rotation axis 4r of the bead core 8. If the inclination angle θ2 is less than 5 degrees, when viewed in the Z direction, the overlap between the rotary drum 3 and the bead core 8 becomes larger, so it is difficult to increase the drum diameter of the rotary drum 3. If the inclination angle θ2 is greater than 25 degrees, the difference from the inclination angle θ1 becomes larger, so it is difficult to stick the rubber sheet S properly to the inner peripheral surface 8a of the bead core 8.

[0044] The inclination angle θ2 is preferably in the range of ±5 degrees with respect to the inclination angle θ1, more preferably in the range of ±2 degrees, and particularly preferably ±0 degrees. That is, the inclination angle θ2 is particularly preferably the same as the inclination angle θ1, for example, 15 to 20 degrees. If the inclination angle θ2 exceeds the range of ±5 degrees with respect to the inclination angle θ1, it is difficult to stick the rubber sheet S on the rotary drum 3 to the inner peripheral surface 8a of the bead core 8.

[0045] Next, the positional relationship between the extruder 2 and the rotary drum 3 will be described. As Figure 1 shown, the discharge port formed on the end face 20b of the gear pump 20 and the rotation axis 3r of the rotary drum 3 are arranged in the same XY plane. On the XY plane including the discharge port of the gear pump 20 and the rotation axis 3r of the rotary drum 3, the end face 20b of the gear pump 20 is arranged inclined with respect to the outer peripheral surface 3a of the rotary drum 3. The angle θ3 formed by the end face 20b of the gear pump 20 and the outer peripheral surface 3a of the rotary drum 3 is 30 degrees or less, preferably 20 degrees or less. By setting the angle θ3 to 30 degrees or less, the bending of the rubber flow path formed inside the die 21 can be reduced, so that the flow velocity difference in the opening width direction of the die 21 can be reduced.

[0046] As described above, the bead core covering device 1 according to the present embodiment is a bead core covering device 1 that covers an annular bead core 8 with a strip-shaped rubber sheet S, and includes: an extruder 2 that extrudes the rubber sheet S; a rotating drum 3 that winds the rubber sheet S extruded from the extruder 2; a covering device 4 that supports the bead core 8 rotatably in such a manner that the outer peripheral surface 3a of the rotating drum 3 approaches the inner peripheral surface 8a of the bead core 8 at a position downstream of the extruder 2 in the rotation direction R1 of the rotating drum 3; and a control unit that controls the extruder 2, the rotating drum 3, and the covering device 4 so that the rubber sheet S extruded from the extruder 2 is wound from the front end around the outer peripheral surface 3a of the rotating drum 3, and before the entire circumference of the rubber sheet S enters the outer peripheral surface 3a of the rotating drum 3, a part in the width direction of the rubber sheet S located on the outer peripheral surface 3a of the rotating drum 3 is pasted from the front end to the inner peripheral surface 8a of the rotating bead core 8, and the remaining part in the width direction of the rubber sheet S pasted to the inner peripheral surface 8a of the bead core 8 is wound 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 disposed inclined with respect to the rotation axis 4r of the bead core 8 in the same plane as the rotation axis 4r of the bead core 8.

[0047] According to this structure, the overlap between the rotating drum 3 and the bead core 8 can be reduced when observed in the Z direction, and thus the drum diameter of the rotating drum 3 can be increased to be close to the inner diameter of the bead core 8.

[0048] In addition, in the bead core covering device 1 according to the present embodiment, the rotation axis 3r of the rotating drum 3 is inclined with respect to the rotation axis 4r of the bead core 8 at an angle θ2 of 15 ± 10 degrees.

[0049] According to this structure, the drum diameter of the rotating drum 3 can be increased. Moreover, even in the case of a bead core 8 in which the inner peripheral surface 8a is inclined with respect to the rotation axis 4r of the bead core 8 as shown in Figure 3 , the rubber sheet S can be appropriately pasted on the inner peripheral surface 8a of the bead core 8.

[0050] In addition, in the bead core covering device 1 according to the present embodiment, it is configured to include: a gear pump 20 that is connected to the front end side in the extrusion direction of the extruder 2 and has a discharge port for discharging the rubber supplied from the extruder 2 formed on the end surface 20b; and a die 21 that is connected to the front end side in the extrusion direction of the gear pump 20 and extrudes the rubber supplied from the gear pump 20 as the rubber sheet S, and in a plane including the discharge port and the rotation axis 3r of the rotating drum 3, the angle θ3 formed by the end surface 20b of the gear pump 20 and the outer peripheral surface 3a of the rotating drum 3 is 30 degrees or less.

[0051] According to this structure, the bending of the rubber flow path formed inside the die 21 can be reduced, and thus the flow velocity difference in the opening width direction of the die 21 can be reduced.

[0052] In addition, in the bead core coating device 1 according to the present embodiment, the drum diameter of the rotary drum 3 is configured to be 0.3 times or more of the inner diameter of the bead core 8.

[0053] With this structure, the circumferential contact area between the rubber sheet S on the rotary drum 3 and the bead core 8 becomes larger, and thus it is easy to attach the rubber sheet S to the bead core 8.

[0054] In addition, in the bead core coating device 1 according to the present embodiment, the covering device 4 is configured to include a pressing roller 41 that presses the bead core 8 while facing the rotary drum 3 with the bead core 8 interposed therebetween. The pressing roller 41 has a roller main body 411 and a flange 412 provided at the axial end of the roller main body 411.

[0055] With this structure, when the rubber sheet S is attached to the inner peripheral surface 8a, it is possible to prevent the bead core 8 from being pressed by the rotary drum 3 and moving in the axial direction.

[0056] As described above, the embodiments of the present disclosure have been described based on the drawings, but the specific structure is not limited to these embodiments. The scope of the present disclosure is shown not only by the description of the above embodiments, but also by the scope of claims, and also includes meanings equivalent to the scope of claims and all modifications within the scope.

[0057] The structures adopted in the above embodiments can be used in any other embodiments. The specific structure of each part is not limited to the above embodiments, and various modifications can be made without departing from the gist of the present disclosure.

[0058] (1) In the bead core coating device 1 according to the above embodiment, the rotation axis 3r of the rotary drum 3 is inclined at an angle θ2 of 15 ± 10 degrees with respect to the rotation axis 4r of the bead core 8. However, the bead core coating device 1 is not limited to this structure. For example, when the inclination angle θ1 of the inner peripheral surface 8a of the bead core 8 with respect to the rotation axis 4r is less than 15 degrees, it is sometimes preferable to make the inclination angle θ2 less than 15 degrees.

[0059] (2) In the bead core coating device 1 according to the above-described embodiment, it is configured to include: a gear pump 20 connected to the front end side in the extrusion direction of the extruder 2, and a discharge port for discharging the rubber supplied from the extruder 2 is formed on the end face 20b; and a die 21 connected to the front end side in the extrusion direction of the gear pump 20, and the rubber supplied from the gear pump 20 is extruded as a rubber sheet S. In a plane including the discharge port and the rotation axis 3r of the rotating drum 3, the angle θ3 formed by 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 structure. For example, when the die 21 is provided 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, and thus, the drum diameter of the rotating drum 3 can be further increased. In addition, in the above-described 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, but it is not limited thereto, and the end face 20b of the gear pump 20 may also be parallel to the outer peripheral surface 3a of the rotating drum 3.

[0060] (3) In the bead core coating device 1 according to the above-described embodiment, it is configured that the drum diameter of the rotating drum 3 is 0.3 times or more of the inner diameter of the bead core 8. However, the bead core coating device 1 is not limited to this structure. For example, when the inner diameter of the bead core 8 is large enough, even if the drum diameter of the rotating drum 3 is less than 0.3 times the inner diameter of the bead core 8, the circumferential contact area between the rubber sheet S on the rotating drum 3 and the bead core 8 can be appropriately ensured.

[0061] (4) In the bead core coating device 1 according to the above-described embodiment, it is configured that the position where the front end of the die 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 it is not limited thereto, and they may also be offset by 90° or 270°.

[0062] Reference Signs

[0063] 1... Bead core coating device

[0064] 2... Extruder

[0065] 3... Rotating drum

[0066] 3a... Outer peripheral surface of the rotating drum

[0067] 3r... Rotation axis of the rotating drum

[0068] 4... Coating device

[0069] 4r... Rotation axis of the bead core

[0070] 8... Bead core

[0071] 8a... Inner circumferential surface of the bead core

[0072] 8b... Lower side surface of the bead core

[0073] 8c... Upper side surface of the bead core

[0074] 8d... Outer circumferential surface of the bead core

[0075] 8e... Upper side surface of the bead core

[0076] 8f... Lower side surface of the bead core

[0077] 20... Gear pump

[0078] 20a... Gear

[0079] 20b... End face of the gear pump

[0080] 21... Die

[0081] 41... Pressing roller

[0082] 41A... Rotating shaft of the pressing roller

[0083] 42 - 46... Rollers

[0084] 47... Guide roller

[0085] 411... Roller body

[0086] 412... Flange

[0087] R1... Rotation direction of the rotating drum

[0088] R2... Rotation direction of the bead core

[0089] S... Rubber sheet

[0090] θ1... Tilt angle of the inner circumferential surface of the bead core relative to the rotating shaft

[0091] θ2... Tilt angle of the rotating shaft of the rotating drum relative to the rotating shaft of the bead core

[0092] θ3... Angle formed between the end face of the gear pump and the outer circumferential surface of the rotating drum.

Claims

1. A bead core coating device that uses a strip-shaped rubber sheet to coat a ring-shaped bead core, wherein, The bead core covering device includes: An extruder that extrudes the rubber sheet; A rotating drum that winds the rubber sheet extruded from the extruder; A covering device that supports the bead core rotatably in such a manner that the outer peripheral surface of the rotating drum approaches the inner peripheral surface of the bead core at a position downstream of the extruder in the rotation direction of the rotating drum; and 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 from the front end around the outer peripheral surface of the rotating drum, and before the rubber sheet is wound around the entire circumference of the outer peripheral surface of the rotating drum, a part in the width direction of the rubber sheet located on the outer peripheral surface of the rotating drum is adhered to the inner peripheral surface of the rotating bead core from the front end, and the remaining part in the width direction of the rubber sheet adhered 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 rotating drum is disposed inclined with respect to the rotation axis of the bead core in the same plane as the rotation axis of the bead core.

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

3. The bead core covering device according to claim 1 or 2, wherein The bead core covering device includes: A gear pump connected to the front end side in the extrusion direction of the extruder, and having a discharge port formed on the end face for discharging the rubber supplied from the extruder; and A die connected to the front end side in the extrusion direction of the gear pump, and extruding the rubber supplied from the gear pump as the rubber sheet, In a plane including the discharge port and the rotation axis of the rotating drum, the angle formed by the end face of the gear pump and the outer peripheral surface of the rotating drum is 30 degrees or less.

4. The bead core covering device according to claim 1 or 2, wherein The drum diameter of the rotating drum is 0.3 times or more of the inner diameter of the bead core.

5. The bead core covering device according to claim 1 or 2, wherein The covering device includes a pressing roller that presses the bead core while facing the rotating drum with the bead core therebetween, The pressing roller has a roller body and a flange provided at the axial end of the roller body.

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