JP2007320141A - Manufacturing method of run-flat tire support and mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a run-flat tire support capable of efficiently molding the run-flat tire support excellent in centrifugal force resistance, and a mold used in this manufacturing method. <P>SOLUTION: A cord material is wound around the outer peripheral surface of the ring part 11b, which constitutes the outer peripheral side part of an inner mold 11 for forming the rim mounting surface of the run-flat tire support, in a state that the ring part 11b is detached from the mold to form a reinforcing material. Thereafter, the ring part 11b is externally fitted to the core part 11a constituting the inner peripheral side part of the inner mold 11 and combined with an outer mold 12 for forming the outer peripheral surface of the run-flat tire support and horizontal molds 10 and 13 for forming the side surface of the run-flat tire support to form a ring-shaped cavity 16 and the raw material for forming the run-flat tire support is supplied in the ring-shaped cavity 16 to be cured. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a method for manufacturing a run-flat tire support that is mounted on a rim of a pneumatic tire and that can be safely driven while maintaining the tire outer diameter when the tire internal pressure decreases, and the manufacturing method thereof. And related molds.

  The run-flat tire is a tire having durability that can withstand the vehicle load and running until it reaches the nearest service facility in a state where the tire internal pressure is greatly reduced due to puncture or the like (run-flat state). As a run-flat tire, a side-reinforcement type in which the side portion of the tire is reinforced and a core type in which a run-flat tire support body (hereinafter sometimes simply referred to as a support body) is disposed inside the tire are practical. It has become. As an example of the latter, Patent Document 1 listed below discloses a support made of a flexible elastomer material, and the inner peripheral side portion thereof is provided with an anti-centrifugal force resistance to prevent lifting during high-speed rotation. Reinforcing material is buried.

  In general, the support is molded by a RIM molding method using a mold that forms a ring-shaped cavity (for example, see Patent Document 2 below). According to such a forming method, the support is formed by supplying the forming raw material of the support to the cavity in which the reinforcing material is disposed and curing the reaction. However, the reinforcing material is not exposed on the rim mounting surface of the support from the viewpoint of securing the mounting of the support and the adhesion to the rim.

  FIG. 10 is a longitudinal cross-sectional view schematically showing a mold opening (a) mold opening state and (b) mold clamping state, and shows a state where the support is molded. The cavity 52 has a ring shape whose axial direction is up and down in the clamped state, and a ring-shaped reinforcing material 53 is disposed therein. The reinforcing material 53 is placed on the horizontal mold 50 that forms the side surface of the support body in the mold open state, and maintains a standing posture by using the rigidity thereof. Patent Document 2 below describes such a ring-shaped reinforcing material having relatively high rigidity. The reinforcing member 53 is extrapolated at a position away from the outer peripheral surface of the middle die 51 forming the rim mounting surface of the support, and is disposed so as not to be exposed to the rim mounting surface of the support. In such a method, the reinforcing material can be disposed in a short time, and the high productivity of the RIM molding method can be utilized.

  Patent Document 3 below discloses a method of forming a reinforcing material by winding a cord material around an outer peripheral surface of a medium size. FIG. 11 is a perspective view showing the reinforcing material forming process, and shows a state in which the cord material 8 supplied from the bobbin 34 is wound around the outer peripheral surface of the disk-shaped middle die 55. The middle die 55 is configured to be rotatable about a rotation axis, and the cord material 8 is wound so as to have a predetermined tension via the tension load device 35. Therefore, the ring-shaped reinforcing material 53 as described above is used. Compared with the case of arranging a support, it is possible to form a support having excellent centrifugal force resistance.

A plurality of concave grooves 56 extending in the axial direction are formed on the outer peripheral surface of the middle die 55 at a predetermined pitch in the circumferential direction, and a convex portion corresponding to the concave grooves is formed on the inner periphery of the support body, thereby reinforcing the reinforcing material. Can be prevented from being exposed to the rim mounting surface. The middle die 55 on which the reinforcing material is formed is attached to the molding die and used for molding the support. However, in this method, it takes time to wind the cord material 8, and the work of attaching and detaching the middle die 55 becomes complicated, and the high productivity of the RIM molding method cannot be fully utilized. .
Japanese Patent Laid-Open No. 10-6721 Special table 2004-508977 gazette JP 2005-313690 A

  The present invention has been made in view of the above circumstances, and its purpose is to provide a method for producing a run flat tire support capable of efficiently forming a run flat tire support excellent in centrifugal force resistance, and It is providing the shaping | molding die used for the manufacturing method.

  The above object can be achieved by the present invention as described below. That is, the method for manufacturing the run-flat tire support of the present invention is a state in which the ring portion constituting the outer peripheral side portion of the middle mold forming the rim mounting surface of the run-flat tire support is removed from the mold. A step of forming a reinforcing material by winding a cord material around the outer periphery, and an outer mold that forms an outer peripheral surface of the run-flat tire support by externally fitting the ring portion to a core portion constituting the inner peripheral side portion of the middle mold And a horizontal mold that forms a side surface, and a step of forming a ring-shaped cavity, and a step of supplying a raw material for forming a run-flat tire support to the cavity and curing it.

  The method of manufacturing a support according to the present invention forms a reinforcing material by winding a cord material around the outer periphery of the ring portion in a state where the ring portion constituting the outer peripheral portion of the middle mold is removed from the molding die. Therefore, while the cord material is wound, the support body can be molded by externally fitting another ring portion on which the reinforcing material is formed in advance to the core portion. Further, while the ring portion around which the cord material is wound is externally fitted to the core portion and the support is formed, the cord material can be wound around another ring portion to form the reinforcing material.

  As described above, according to the present invention, it is possible to eliminate the problem that the winding of the cord material takes time and the productivity is lowered, and it is possible to efficiently mold the support, and the productivity of the RIM molding method. As compared with the case where a reinforcing material formed in a ring shape as described above is disposed, the cord material to be wound can be loaded with an appropriate tension. A support having excellent strength can be formed. Of course, the ring portion is lighter and easier to handle than the middle mold, and the workability is better than when the entire middle mold is removed from the mold and the cord material is wound.

  The run flat tire support mold according to the present invention includes a middle mold that forms a rim mounting surface of the run flat tire support, an outer mold that forms an outer peripheral surface of the support, and a side surface of the support. A run-flat tire support mold that forms a ring-shaped cavity in a mold-clamped state, wherein the middle mold constitutes a core part that constitutes an inner peripheral part thereof and an outer peripheral part thereof And a ring portion configured to be externally fitted to the core portion.

  The mold having the above configuration can be used in the above-described method for producing a support. That is, the intermediate mold includes a core part that forms the inner peripheral part thereof, and a ring part that constitutes the outer peripheral part of the core part and can be fitted onto the core part, thereby removing the ring part from the mold. In this state, a cord material can be wound around the outer periphery to form a reinforcing material, and in the meantime, another ring portion on which a reinforcing material has been formed in advance is fitted over the core portion to form a support. Can do. Further, while the ring portion around which the cord material is wound is externally fitted to the core portion and the support is formed, the cord material can be wound around another ring portion to form the reinforcing material. As a result, a run flat tire support having excellent centrifugal resistance can be efficiently formed.

[Configuration of run-flat tire support]
FIG. 1 is a tire meridian cross-sectional view showing an example of a run-flat tire. FIG. 2 is a partially broken perspective view of a run-flat tire support body assembled to the run-flat tire.

  The tire 2 includes a pair of bead portions 21, a sidewall portion 22 that extends outward from the bead portion 21 in the tire radial direction, and a tread portion 23 that connects the outer peripheral side ends of the sidewall portions 22. Each bead portion 21 is attached to the bead seats 31 and 32 of the rim 3, and the tire 2 is fitted and fixed to the rim 3 in a state in which leakage of air inside the tire is prevented. The rim 3 of the present embodiment is an integrated rim in which the bead seat 31 is formed below the inner diameter of the run-flat tire support 4, and the tire 2 has a left-right asymmetric cross-sectional shape.

  The support body 4 is arranged on the outer peripheral side of the base 41 mounted on the mounting surface 33 of the rim 3 and a cylindrical shape that can come into contact with the inner surface of the tread portion 23 when the tire internal pressure decreases. A cap 42 and an annular main body 43 extending in the radial direction R between the base 41 and the cap 42 and integrally connecting them are formed into an annular body having a rectangular cross section. The inner diameter of the base 41 is set slightly smaller than the outer diameter of the mounting surface 33, and can be assembled to the rim 3 by pushing the support body 4 from the bead seat 31 side and extrapolating it.

  The annular main body 43 includes a circumferential wall 44 extending along the circumferential direction, and a width direction wall 45 extending along the width direction W. The width direction wall 45 extends so as to connect ends of the circumferential wall 44 in a substantially zigzag shape, and concave portions 47 that are tapered and extend in the width direction are alternately formed. The recess 47 can reduce the weight of the core and can dissipate heat generated during run-flat travel to the outside to enhance the heat dissipation effect and contribute to improving the durability of the support 4.

  A reinforcing material 5 is embedded in the base 41 in a ring shape, and the anti-centrifugation resistance is enhanced to suppress the lifting during high-speed rotation, thereby ensuring a stable mounting strength. The reinforcing material 5 is slightly separated from the innermost surface of the support 4 toward the outer peripheral side, and from the viewpoint of securing the mounting property of the support 4 and the adhesion to the rim 3, and the mounting surface 33 by contact with the reinforcing material 5. In view of preventing damage to the rim, the rim mounting surface 46 is arranged so as not to be exposed.

  The reinforcing material 5 is constituted by a cord material wound in the circumferential direction, and any cord material known in the technical field of run-flat tire supports can be used without limitation. Examples include rayon cords, polyamide cords such as nylon-6,6, polyester cords such as polyethylene terephthalate, aramid cords, glass fiber cords, Kevlar fiber cords, carbon fibers, steel cords, and the like. It can be used in combinations of more than one species.

  The support 4 is essentially composed of a flexible material, and any of a thermoplastic elastomer and a crosslinked rubber material can be used. However, any support can be used as long as it has the characteristics required as a support. It is. As the thermoplastic elastomer, known thermoplastic elastomers can be used without limitation, and specific examples include polyester elastomers, polyolefin elastomers, polyamide elastomers, ionomers, polyurethane elastomers, and the like.

  The rubber material constituting the crosslinked rubber material includes natural rubber, styrene butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IIR), nitrile rubber (NBR), hydrogenated nitrile rubber (hydrogenated NBR). ), Synthetic rubbers such as chloroprene rubber (CR), ethylene propylene rubber (EPDM), fluorine rubber, silicon rubber, acrylic rubber, and urethane rubber. These rubber materials may be used in combination of two or more as required. Further, as the flexible material, a foamed elastic material may be used, and the foamed materials exemplified above can be used.

[Configuration of mold]
FIG. 3 is a longitudinal sectional view schematically showing the mold opening state of the mold of the support 4. FIG. 4 is a perspective view of the middle mold of the mold as viewed from below. The mold is composed of a first horizontal mold 10 (lower mold) that forms the side surface of the support 4 and an upper mold that can be opened and closed with respect to the first horizontal mold 10. The upper mold is mounted on the rim of the support 4. A disk-shaped middle mold 11 that forms the surface 46, a ring-shaped outer mold 12 that also forms the outer peripheral surface, and a second horizontal mold 13 that is formed integrally with the outer mold 12. In addition, the first horizontal mold 10 and the second horizontal mold 13 are alternately provided with protrusions 15 for forming the recesses 47 in the support 4.

  As shown in FIGS. 4 and 5, the middle mold 11 includes a core portion 11 a that constitutes the inner peripheral side portion thereof, and a ring portion 11 b that constitutes the outer peripheral side portion thereof and can be fitted onto the core portion 11 a. Prepare. In this embodiment, the hook-shaped groove 28 is formed on the outer peripheral surface of the core portion 11a, and the convex portion 29 that can be fitted into the hook-shaped groove 28 is formed on the inner peripheral surface of the ring portion 11b. By simply extrapolating 11b to the core 11a from below and turning it slightly in the circumferential direction, it can be easily fitted and positioned. A plurality of protrusions 14 extending in the axial direction (vertical direction) of the support 4 are provided on the outer peripheral surface of the ring portion 11b at a predetermined pitch in the circumferential direction.

  FIG. 6 is a vertical cross-sectional view schematically showing the mold clamping state of the molding die. In the mold clamping state, a ring-shaped cavity 16 is formed. The first horizontal mold 10 is formed with a sprue 17 extending in the vertical direction and a lower concave groove that radiates from the upper end of the sprue 17 and communicates with the cavity 16. An upper concave groove that constitutes the runner 18 is formed so as to face the surface. The raw material for forming the support 4 is supplied from an injection mechanism (not shown) to the sprue 17 and injected into the cavity 16 via the runner 18.

[Method for producing run-flat tire support]
Hereinafter, a procedure for forming the support 4 will be described. First, the ring part 11b is removed from the mold in the mold open state, or the ring part 11b that has already been removed is prepared. The removal of the ring part 11b may be performed in the reverse manner to the external fitting to the core part 11a described above.

  Subsequently, as shown in FIG. 7, after the ring portion 11 b is externally fitted to the drum 36 that is configured to be rotatable about the rotation shaft 37, the cord material 8 wound around the bobbin 34 is moved to the drum 36 side. The reinforcing material 5 is formed by being supplied and wound around the outer periphery of the ring portion 11b. A predetermined tension is applied to the cord material 8 by the tension load device 35. Here, the predetermined tension is small enough to maintain the uniformity of the arrangement of the cord members 8 so that the fixing force with respect to the rim 3 is sufficiently exerted. It is large enough not to be difficult. Accordingly, the centrifugal force resistance of the support body 4 is improved as compared with the case where a reinforcing material previously formed in a ring shape is disposed in the cavity.

  As shown in FIG. 8, the reinforcing member 5 is formed in a ring shape on the outer periphery of the ring portion 11 b so as to be bridged between the protrusions 14, and between the outer peripheral surface of the ring portion 11 b and the reinforcing member 5. A gap 19 is provided. It should be noted that the outlet of the runner 18 is preferably positioned in the gap between the cord members 8 constituting the reinforcing member 5 so as not to affect the flowability of the forming raw material in the subsequent process.

  Next, the ring part 11b is removed from the drum 36, and the middle part 11 is configured by being externally fitted to the core part 11a of the mold. As described above, the ring portion 11b can be easily fitted on the core portion 11a, and the ring portion 11b is positioned in the circumferential direction and the axial direction so that the upper concave groove of the ring portion 11b is in series with the upper concave groove of the core portion 11a. Is done. Then, as shown in FIG. 6, the upper die is lowered to a clamping state, and the first horizontal die 10, the outer die 12 and the second horizontal die 13 are combined with the middle die 11 to form a ring-shaped cavity 16. In the cavity 16, the reinforcing material 5 is disposed on the inner peripheral side portion thereof, and the protrusions 15 are staggered vertically.

  Subsequently, the raw material for forming the support 4 is injected and injected into the cavity 16 to be cured by reaction. The injected forming raw material is filled from the inner peripheral side portion of the cavity 16 and filled into the cavity 19 so as to surround the reinforcing material 5 and enter the gap of the cord material 8 constituting the reinforcing material 5. To do. As a result, the reinforcing member 5 can be embedded in the base 41 of the support 4 and not exposed to the rim mounting surface 46. After the forming raw material is cured, the support 4 is removed by opening the mold.

  In the formation of the support 4 described above, while the cord material 8 is being wound, another ring portion in which a reinforcing material is formed in advance can be externally fitted to the core portion 11a to form the support. Further, while the ring portion 11b is externally fitted to the core portion 11a and the support is formed, the cord material 8 can be wound around another ring portion to form a reinforcing material. As a result, it is possible to eliminate the problem that the winding of the cord material takes time and the productivity is lowered, and the support can be efficiently molded, and the high productivity of the RIM molding method is fully utilized. be able to.

[Another embodiment]
The present invention is not limited to the embodiment described above, and various improvements and modifications can be made without departing from the spirit of the present invention. The fitting mechanism between the core portion and the ring portion and the support body can be changed. The structure and the shape of the spacer are not limited to the above.

  In the above-described embodiment, the example in which the protrusion is provided on the outer peripheral surface of the ring portion has been described, but the present invention is not limited to this. For example, a reinforcing material may be formed by winding a belt-like fiber material around the outer peripheral surface of the ring portion and winding a cord material around the outer periphery. Such a fiber material can be composed of a woven fabric or a net, and a known fiber material can be used without limitation. Examples include rayon, polyamide fibers such as nylon-6,6, polyester fibers such as polyethylene terephthalate, and aramid fibers. These fiber materials are preferably subjected to a treatment for improving the adhesion with the forming raw material.

  Further, the reinforcing material 5 may be formed by arranging a plurality of spacers 9 as shown in FIG. 9 on the outer peripheral surface of the ring portion 11b and winding a cord material so as to be spanned around the outer periphery. In the illustrated example, spacers 9 having a trapezoidal cross section and extending in the axial direction are arranged at a predetermined pitch in the circumferential direction. The material of the spacer 9 is not particularly limited, but is preferably a resin molded product having excellent adhesion to the support forming raw material. Such a spacer 9 may be left attached to the molded support body, so that the rim mounting surface of the support body becomes a smooth ring-shaped surface. Adhesion can be improved.

Tire meridian cross-sectional view showing an example of a run-flat tire A perspective view showing a part of a run-flat tire support broken away Longitudinal sectional view schematically showing the mold open state of the mold Perspective view of the middle mold viewed from below Front view of core and ring Longitudinal sectional view schematically showing the clamping state of the mold The figure which shows a mode that a cord material is wound around a ring part Cross-sectional view partially showing the middle size View from below of the middle mold with reinforcing material formed through spacers It is a longitudinal cross-sectional view which shows roughly the (a) mold opening state and (b) mold clamping state of a shaping | molding die, and is a figure explaining the manufacturing method of the conventional support body The figure which shows a mode that a cord material is wound around the outer peripheral surface of a medium size

Explanation of symbols

2 Tire 3 Rim 4 Run-flat tire support 5 Reinforcement material 8 Cord material 9 Spacer 10 First horizontal mold 11 Middle mold 11a Core part 11b Ring part 12 Outer mold 13 Second horizontal mold 14 Projection 16 Cavity 34 Bobbin 35 Tension load device 36 Drum 41 Base 46 Rim mounting surface

Claims (2)

A step of forming a reinforcing material by winding a cord material around the outer periphery of the ring portion in a state where the ring portion constituting the outer peripheral side portion of the middle mold forming the rim mounting surface of the run-flat tire support is removed from the molding die; ,
A ring-shaped cavity is formed by combining the ring portion with a core portion constituting the inner peripheral side portion of the middle mold, and combining the outer mold forming the outer peripheral surface of the run-flat tire support and the horizontal mold forming the side surface. Forming, and
A method for producing a run-flat tire support, comprising the step of supplying a forming raw material of the run-flat tire support to the cavity and curing it. A ring-shaped cavity in a mold-clamped state, comprising a middle mold that forms a rim mounting surface of a run-flat tire support, an outer mold that forms an outer peripheral surface of the support, and a horizontal mold that forms a side surface of the support In the mold of the run-flat tire support to form
A run-flat tire support, wherein the intermediate mold includes a core portion that forms an inner peripheral portion thereof, and a ring portion that forms an outer peripheral portion of the intermediate die and is configured to be externally fitted to the core portion. Mold.

Images