JP2018086733A - Manufacturing method for core member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a core member capable of suppressing a winding failure.SOLUTION: A manufacturing method for a core member 25 for a tire comprises: an upward winding step in which a bead wire 22 is wound from one side to the other side in an axial direction while inclining toward outside from radially inside; and a downward winding step in which a bead wire 22 is wound from the other side to the one side in the axial direction while inclining toward inside from radially outside. Tension applied to the bead wire 22 in the downward winding step is smaller than tension applied to the bead wire 22 in the upward winding step. Preferably, downward pressing force with which a tension roller is pressed against the bead wire 22 in the downward winding step is smaller than upward pressing force with which the tension roller is pressed against the bead wire 22 in the upward winding step.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method for manufacturing a core member of a tire. Specifically, the present invention relates to a method for manufacturing a core member obtained by winding a bead wire.

  The tire has a core for fitting to the rim. Generally, this core is formed from a core member around which a bead wire is wound. As such a core member, a member whose bottom surface is inclined with respect to the axial direction may be used. In the core member whose bottom surface is inclined, the wound bead wire is likely to collapse.

  For example, JP2013-78902A, JP2014-83768A, and JP2015-196243A disclose a method of forming a core member. In these molding methods, the collapse of the core member with the inclined bottom surface can be reduced.

JP 2013-78902 A JP 2014-83768 A JP2015-196243

  The inclination angle of the bottom surface of the core member varies depending on the tire specifications. In particular, the core member having a large bottom surface inclination angle is likely to collapse. It is not easy to reduce the collapse while corresponding to the molding of various core members having different bottom surface inclination angles.

  The objective of this invention exists in provision of the manufacturing method of the core member which can suppress winding collapse.

  The tire core member manufacturing method according to the present invention is a core member manufacturing method in which the bottom surface is formed to be inclined with respect to the axial direction. This method includes an up-winding step in which a bead wire is wound from one side in the axial direction toward the other in the radial direction from the inner side toward the outer side, and an inclination from the other in the axial direction toward the other side in the radial direction. And a downward winding process in which the bead wire is wound. The downward tension applied to the bead wire in the downward winding process is smaller than the upward tension applied to the bead wire in the upward winding process.

  Preferably, the downward pressing force with which the tension roller is pressed against the bead wire in the downward winding step is smaller than the upward pressing force with which the tension roller is pressed against the bead wire in the upward winding step.

  Preferably, the inclination angle θ of the bottom surface of the core member with respect to the axial direction is 18 degrees or more.

The tire manufacturing method according to the present invention includes a core member forming step for forming a core member, a preforming step in which a member for forming each part including the core member is combined to form a raw cover, and the raw cover is vulcanized. And a vulcanization step for obtaining a tire.
In the core member forming step, the bottom surface of the core member is formed to be inclined with respect to the axial direction. The core member forming step includes an upward winding step in which a bead wire is wound from one side in the axial direction toward the other side toward the other side in the radial direction, and a step from the other side in the radial direction from the other side in the axial direction. And a descending winding step in which the bead wire is wound in an inclined direction. The downward tension applied to the bead wire in the downward winding process is smaller than the upward tension applied to the bead wire in the upward winding process.

  The core member manufacturing apparatus according to the present invention includes a disk-shaped bead former having a groove provided on the outer periphery thereof, a feeder for supplying a bead wire wound around the groove, and a bead wire wound around the groove. A tension applicator for applying tension. The bottom surface of the groove extends from one side in the axial direction to the other side while being inclined from the inner side in the radial direction toward the outer side. The supply machine has a function of moving a position for supplying the bead wire in the axial direction when the bead wire is wound around the groove. The tension applicator is a tension when the position where the bead wire is supplied moves from one axial direction to the other, and the tension when the position where the bead wire is supplied moves from the other axial direction to the other. It has a function to make it larger.

  In the manufacturing method of the core member according to the present invention, the downward tension is smaller than the upward tension when the bead wire is wound. In the downward winding process, the bead wire is easily wound at a predetermined winding position. In this method, it is suppressed that the winding arrangement of the bead wires is disturbed. This method can suppress the collapse of the core member.

FIG. 1 is a cross-sectional view showing a part of a pneumatic tire manufactured by the manufacturing method according to the present invention. FIG. 2 is a conceptual diagram of a core member manufacturing apparatus used in the manufacturing method according to the present invention. FIG. 3 is an explanatory diagram of a bead former of the manufacturing apparatus of FIG. FIG. 4 is a cross-sectional view showing a core member wound around the bead former of FIG. 3 together with a part of the bead former. FIG. 5A is an explanatory view of a winding process of the core member by the bead former of FIG. 3, and FIG. 5B is another explanatory view of the winding process of the core member, and FIG. These are other explanatory drawings of the winding process of this core member.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

  FIG. 1 shows a part of a tire 2 manufactured by the manufacturing method according to the present invention. In FIG. 1, the vertical direction is the radial direction of the tire 2, the horizontal direction is the axial direction of the tire 2, and the direction perpendicular to the paper surface is the circumferential direction of the tire 2. The tire 2 is a pneumatic tire. The tire 2 is a tubeless type. The tire 2 is attached to a truck, a bus or the like.

  The tire 2 includes a bead 4, a sidewall 6, a clinch 8, a carcass 10, an inner liner 12, and a filler 14. The bead 4 includes a core 16, a first apex 18, and a second apex 20. The core 16 has a ring shape and includes a wound bead wire 22. The bead wire 22 includes a non-stretchable wire. In the core 16, the bead wire 22 is wound in a spiral shape.

  A straight line Lα in FIG. 1 is a straight line extending along the bottom surface 16 a of the core 16. The straight line L1 represents a straight line extending in the axial direction. A double arrow α represents an angle at which the straight line Lα and the straight line L1 intersect. This angle α is referred to as the inclination angle of the core 16. A plurality of cross sections 24 of the wound bead wire 22 are arranged along the straight line Lα. A plurality of rows in which the cross sections 24 are arranged are stacked. This row of cross sections 24 is inclined at an inclination angle α. This inclination angle α is usually set to 15 ° or more in a tubeless type heavy duty tire. In the tire 2, the inclination angle α is 20 °.

  The manufacturing method of the tire 2 includes a preforming step and a vulcanizing step. This preforming step includes a core member forming step for forming the core member 25 (see FIG. 4). This preforming step includes the steps of forming each member for forming each part of the tire, such as the core member 25, the first apex member, the second apex member, the side wall member, the clinch member, the carcass member, and the inner liner member. I have. In the preforming process, these members are combined to form a raw cover. In the vulcanization process, the raw cover is pressurized and heated in a mold. The tire 2 is obtained from the raw cover through this vulcanization step.

  FIG. 2 shows a manufacturing apparatus 26 for the core member 25 used in the core member forming step. The manufacturing device 26 includes a reel 28, a storage device 30, a heater 32, an extruder 34 as a coating device, a tension applying device 36, a supply device 38, and a bead former 40. The manufacturing apparatus 26 includes a control device (not shown). This control device has a function of controlling the reel 28, the storage device 30, the heater 32, the extruder 34, the tension applying device 36, the supply device 38 and the bead former 40.

  A wire body 42 is scraped off the reel 16. A typical material of the wire body 42 is steel. In the manufacturing apparatus 26, the bead wire 22 is formed by coating the outer peripheral surface of the wire body 42 with the rubber composition. The manufacturing method of the core member 25 includes a feeding process, a preheating process, a coating process, and a winding process.

  The reel 28 of FIG. 2 is rotated about its axis in the feeding process. From this reel 28, the wire body 42 is fed out. The drawn wire main body 42 is sent to the storage device 30. The storage device 30 has a buffer function for adjusting the amount of the wire main body 42 sent to the heater 32 and the amount of the wire main body 42 sent from the reel 28. The wire main body 42 is sent to the heater 32 through the storage device 30.

  In the preheating step, the heater 32 heats the wire body 42. The wire body 42 is preheated. The wire body 42 is sent to the extruder 34.

  In the coating process, the outer peripheral surface of the wire body 42 is coated with a rubber composition. In the coating process, the rubber composition is put into the extruder 34. The extruder 34 coats the outer peripheral surface of the wire body 42 with the rubber composition. The coated rubber composition forms a coating layer on the outer peripheral surface of the bead wire 22. The bead wire 22 includes a wire body 42 and a coating layer. The bead wire 22 is sent to the feeder 38.

  In the winding process, the tension applying device 36 applies tension to the bead wire 22. In the manufacturing apparatus 26, the tension roller 36 a of the tension applying machine 36 is pressed against the bead wire 22. The tension roller 36 a is pressed in a direction perpendicular to the axis of the bead wire 22. The tension roller 36 a is pressed between the coating device 4 and the supply device 38. As a result, tension is applied to the bead wire 22. This tension acts in the axial direction of the bead wire 22. The supply device 38 adjusts the supply position of the bead wire 22 with respect to the bead former 40. The bead former 40 rotates and winds the bead wire 22 around the outer periphery thereof. The control device controls the tension applying device 36, the supply device 38, and the bead former 40.

  A one-dot chain line Ax in FIG. 3 represents the rotation axis of the bead former 40. An arrow Q represents the rotation direction of the bead former 40. A double-headed arrow Mx represents the moving direction of the supply device 38. The supply device 38 is movable in parallel with the rotation axis Ax of the bead former 40. The bead former 40 has a disk shape. A groove 44 is formed on the outer peripheral surface of the bead former 40. By rotating the bead former 40, the bead wire 22 to which tension is applied is wound around the groove 44.

  FIG. 4 shows a core member 25 formed by winding the bead wire 22. The outer peripheral surface 44a of the groove 44 is inclined from the inner side toward the outer side in the radial direction from one side in the axial direction to the other side. 4 represents the inclination angle of the outer peripheral surface 44a. This inclination angle θ is also the inclination angle of the bottom surface of the core member 25. The bead wire 22 is wound along the outer peripheral surface 44 a of the groove 44. Thereby, the core member 25 with the inclination angle θ is formed.

  FIG. 5A shows a state where the bead wire 22 is wound around the groove 44. In Fig.5 (a), the bead wire 22 is wound along the outer peripheral surface 44a. The bead wire 22 is wound, and the cross section 24a to the cross section 24b are arranged in order in a direction inclined from the inner side to the outer side in the radial direction from one side to the other side in the axial direction.

  FIG. 5B shows another state in which the bead wire 22 is wound around the groove 44. The cross sections 24a to 24c are arranged in order in a direction inclined from the inner side to the outer side in the radial direction from one axial direction to the other in the axial direction. A cross section 24d is arranged on the outer side in the radial direction of the cross section 24c. The cross sections 24d to 24e are arranged outside the first stage of the cross sections 24a to 24c. The cross sections 24d to 24e are arranged in order in an inclined direction from the outside in the radial direction toward the inside from the other in the axial direction.

  FIG. 5C shows still another state in which the bead wire 22 is wound around the groove 44. The cross section 24d to the cross section 24f are sequentially arranged in a direction inclined from the outside in the radial direction toward the inside from the other in the axial direction. A cross section 24g is arranged on the outer side in the radial direction of the cross section 24f. The cross sections 24g to 24h are arranged outside the second stage of the cross sections 24d to 24f. The cross sections 24g to 24h are arranged in order in a direction inclined from the inner side to the outer side in the radial direction from one axial direction to the other in the axial direction.

  In this winding process, the control device controls the axial position of the feeder 38. The bead wire 22 is disposed at the position of the cross section 24a. The control device sets the tension roller 36a of the tension applying device 36 to the pressing force F1. The tension applying device 36 presses the tension roller 36a against the bead wire 22 with the pressing force F1. The tension T1 is applied to the bead wire 22 by the pressing force F1. The control device rotates the bead former 40. By this rotation, the bead wire 22 is wound.

  When the bead wire 22 is wound once, the control device moves the position of the feeder 38 from one axial direction to the other at a predetermined pitch. At the position where the supply device 38 is moved, the bead former 40 is rotated and the bead wire 22 is further wound. The cross section 24 is arranged adjacent to the other axial direction of the cross section 24a.

  The control device further moves the feeder 38 at a predetermined pitch from one axial direction to the other. The bead wire 22 is wound from one side in the axial direction to the other in a direction inclined from the inner side to the outer side in the radial direction. In this way, the cross-section 24a to the cross-section 24c are arranged in order in a direction inclined from the inner side to the outer side in the radial direction from one side to the other side in the axial direction.

  Further, the bead wire 22 is wound from the cross section 24a to the outside of the cross section 24c. The supply device 38 and the bead former 40 wind the bead wire 22 once around the radial direction of the cross section 24c. The cross section 24d is arranged on the outer side in the radial direction of the cross section 24c. When the bead wire 22 is wound once at the position of the cross section 24d, the control device moves the feeder 38 from the other axial direction toward the other at a predetermined pitch. The control device changes the pressing force F1 of the tension roller 36a to the pressing force F2. This pressing force F2 is smaller than the pressing force F1. A tension T2 is applied to the bead wire 22 by the pressing force F2. This tension T2 is smaller than the tension T1.

  The bead wire 22 is wound and the cross section 24 is arranged adjacent to one axial direction of the cross section 24d. The feeder 38 is moved at a predetermined pitch from the other axial direction to the other. The bead former 40 is rotated, and the bead wire 22 is wound in a direction inclined from the outside in the radial direction toward the inside from the other in the axial direction. The cross section 24d to the cross section 24f are arranged in order inclined from the outside in the radial direction toward the inside from the other in the axial direction. After winding the bead wire 22 once at the position of the cross section 24f, the control device returns the tension T2 of the bead wire 22 to the tension T1 by the tension applying device 36.

  Further, the bead wire 22 is wound from the cross section 24d to the outside of the cross section 24f. The supply device 38 and the bead former 40 wind the bead wire 22 once around the radial direction of the cross section 24f. The cross section 24g is arranged on the outer side in the radial direction of the cross section 24f. When the bead wire 22 is wound once around the position of the cross section 24g, the control device moves the feeder 38 from one axial direction to the other at a predetermined pitch. The feeder 38 moves at a predetermined pitch from one axial direction to the other, and the bead wire 22 is wound while being inclined from the inner side toward the outer side in the radial direction from one side to the other in the axial direction.

  As shown in FIGS. 5 (a) to 5 (c), in this winding process, the cross-sections 24 are arranged in order from one side to the other in the axial direction, inclining from the inner side to the outer side in the radial direction. The winding process includes a winding process and a descending winding process in which the cross-section 24 is inclined and arranged in order from the radially outer side toward the inner side from the other side in the axial direction. The up winding process and the down winding process are alternately repeated to form the core member 25.

  In the downward winding process shown in FIG. 5B, the bead wire 22 is wound in the order of the cross section 24d to the cross section 24e adjacent to the cross section 24 already arranged on the other side in the axial direction. In the downward winding process, the cross-sections 24 are arranged so as to be inclined from the outside in the radial direction toward the inside from the other in the axial direction. As shown in FIG. 5B, the cross section 24 on the one side in the axial direction comes into contact with the outer periphery of the cross section 24 adjacent to the other side at a portion located on the radially inner side of the bead former 40. For this reason, in the descending winding process, the cross section 24 wound on one side easily interferes with the cross section 24 adjacent to the other side. Due to this interference, the cross section 24 wound on one side may be caught by the cross section 24 adjacent to the other side. This catch prevents the cross section 24 wound on one side from being arranged at a predetermined position. This catching causes a shift in the arrangement position of the cross section 24. This shift in the arrangement position causes the core member 25 to collapse.

  In this winding process, the tension T2 in the downward winding process is made smaller than the tension T1 in the upward winding process. Since the tension T2 is small, the cross section 24 wound on one side is not easily caught by the cross section 24 adjacent to the other side. The displacement of the arrangement position of the cross section 24 is unlikely to occur. Thereby, collapse of the core member 25 is suppressed.

  In the core member 25 having the large inclination angle θ, the arrangement position of the cross section 24 is likely to be shifted in the downward winding process. This manufacturing method is suitable for manufacturing the core member 25 having a large inclination angle θ. From this viewpoint, the inclination angle θ of the core member 25 is preferably 16 degrees or more, and more preferably 18 degrees or more.

  In this winding step, the collapse of the core member 25 is suppressed by making the tension T2 smaller than the tension T1. In this winding step, since the magnitude of the tension T1 and the magnitude of the tension T2 are only different, the core member 25 can be easily prevented from being collapsed even in the core member having the inclination angle θ different from the inclination angle. This winding process can easily form various core members having different inclination angles.

  Moreover, since this bead wire 22 is provided with the coating layer of the rubber composition, it is difficult to slip between the cross sections 24. For this reason, in the descending winding process, the cross section 24 wound on one side is easily caught by the cross section 24 adjacent to the other side. In the manufacturing method of the core member 25, since the tension T2 is small, the cross section 24 on one side is not easily caught by the cross section 24 adjacent to the other side. This manufacturing method is suitable for winding the bead wire 22 having a coating layer.

  In this winding process, the tension roller 36 a of the tension applying machine 36 is pressed against the bead wire 22. The tension applicator 36 can apply tension to the bead wire 22 with a simple configuration and can adjust the tension. The tension applying machine 26 can be easily retrofitted to a conventional manufacturing apparatus for the core member 25. The tension roller 36a is rotated and pressed against the bead wire 22 without slipping. Since tension is generated by the tension roller 36a, damage to the bead wire 22 is suppressed.

  The pressing forces F1 and F2 of the tension roller 36a are not particularly limited. The forces F1 and F2 are 0 (N) or more. The forces F <b> 1 and F <b> 2 only need to generate a tension that can be wound around the groove 44 around the bead wire 22. On the other hand, if the pressing forces F1 and F2 are too large, the winding resistance increases. If the pressing forces F1 and F2 are too large, the bead wire 22 is damaged. From these viewpoints, the pressing forces F1 and F2 are preferably 0.5 (N) or less. For example, the pressing force F1 in the upward winding process is set to 0.2 (N) or more and 0.5 (N) or less. The pressing force F2 in the downward winding process is set to 0 (N) or more and smaller than the pressing force F1. The difference between the pressing force F1 and the pressing force F2 is preferably 0.2 (N).

  In this manufacturing apparatus 26, when the control device moves the supply machine 38 from one axial direction to the other, the tension T1 is applied to the bead wire 22 and the supply machine 38 moves from the other axial direction to the other. The bead wire 22 has a function of applying a tension T2. In this manufacturing method, the tension T1 when the position where the bead wire 22 is supplied moves from one axial direction to the other is the tension T1 when the position where the bead wire 22 is supplied moves from the other axial direction to the other. As long as it is larger than T2, it is not necessary to use this control device. For example, a mechanism may be provided in which the pressing force with which the tension roller 36a is pressed against the bead wire 22 varies depending on the axial movement direction of the feeder 38.

  Hereinafter, the effects of the present invention will be clarified by examples. However, the present invention should not be construed in a limited manner based on the description of the examples.

[Example]
The core member was manufactured using the manufacturing apparatus described in the embodiment. In this core member manufacturing method, the tension in the descending winding process is made smaller than the tension in the ascending winding process. The inclination angle θ of the core member was 20 degrees. Further, in this manufacturing method, the bead wire was wound at a higher speed than usual so that the winding collapse easily occurred.

[Comparative example]
A bead member was produced in the same manner as in Example 1 except that the tension in the descending winding process was the same as the tension in the ascending winding process.

[Evaluation of collapse]
The manufactured bead member was inspected for the occurrence of collapse. The incidence of roll-up was calculated. Table 1 shows the evaluation results. This evaluation result is represented by an index with the example being 100. The larger this index is, the smaller the rate of occurrence of collapse. The smaller this index is, the better.

  As shown in Table 1, the manufacturing method of the example has a higher evaluation than the manufacturing method of the comparative example. From this evaluation result, the superiority of the present invention is clear.

  The method described above can be widely applied to the manufacture of a core member whose bottom surface is inclined with respect to the axial direction.

DESCRIPTION OF SYMBOLS 2 ... Tire 4 ... Bead 16 ... Core 22 ... Bead wire 24 ... Cross section 25 ... Core member 26 ... Manufacturing apparatus 36 ... Tension imparting machine 38 ... Supply machine 40 ... Bead former 42 ... Wire body 44 ... Groove

Claims (5)

A method of manufacturing a core member, the bottom surface of which is inclined with respect to the axial direction,
An ascending winding step in which a bead wire is wound from one side in the axial direction toward the other side in a radial direction from the inside to the outside;
A downward winding step in which the bead wire is wound while being inclined inward from the radially outer side toward the other side in the axial direction from the other side,
The downward tension applied to the bead wire in the downward winding step is smaller than the upward tension applied to the bead wire in the upward winding step.
A method for manufacturing a core member of a tire.   The manufacturing method according to claim 1, wherein a downward pressing force by which the tension roller is pressed against the bead wire in the downward winding step is smaller than an upward pressing force by which the tension roller is pressed against the bead wire in the upward winding step.   The manufacturing method according to claim 1, wherein an inclination angle θ of the bottom surface of the core member with respect to the axial direction is 18 degrees or more. A core member forming step of forming the core member;
A preforming step in which a raw cover is formed by combining members forming each part including the core member;
A vulcanization step in which the raw cover is vulcanized to obtain a tire,
In the core member forming step, the bottom surface of the core member is formed to be inclined with respect to the axial direction,
The core member forming step is an upward winding step in which the bead wire is wound from one side in the axial direction toward the other side in the radial direction from the inside in the radial direction, and from the other side in the radial direction toward the other side in the axial direction. A downward winding process in which the bead wire is wound in an inclined direction,
The downward tension applied to the bead wire in the downward winding step is smaller than the upward tension applied to the bead wire in the upward winding step.
Tire manufacturing method. A disk-shaped bead former having a groove provided on the outer periphery thereof, a feeder for supplying a bead wire wound around the groove, and a tension applying device for applying tension to the bead wire wound around the groove. And
The bottom surface of the groove extends from one side in the axial direction to the other side in an inclined manner from the inside in the radial direction to the outside,
The feeder has a function of moving the position of supplying the bead wire in the axial direction when the bead wire is wound around the groove;
The tension when the position where the bead wire is supplied moves from one axial direction to the other, and the tension when the position where the bead wire is supplied moves from the other axial direction to the other. An apparatus for manufacturing a core member having a larger function.

Images