JP2009248484A - Method and mold for molding of tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a mold for molding of tires enabling smooth mold release of a tire from the side mold portion on mold opening. <P>SOLUTION: The tire molding method comprises, while bringing the side mold portion 3 into contact with the outer surface of the sidewall portion of a tire T, bringing the tread mold portion of the tire T consisting of a combination of sectors 5 divided in the circumferential direction of the tire into contact with the outer surface of the tread portion of the tire T so as to vulcanize the tire T. On displacing the sectors 5 outside in the radial direction of the tire after vulcanization, the inner peripheral surface in the vicinity of the engagement surface 5a where the sectors 5 are engaged in the side mold portion 3 is engaged in the tire T, and the outer surface portion Ts of the tire extending over the engagement surface 5a is deformed to make detached from the side mold portion 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a tire molding method including a step of vulcanizing a tire, and a tire mold for vulcanizing and molding a tire.

  Generally, as shown in FIG. 13, a segmented type tire molding die includes a tread mold portion 11 that molds the outer surface of the tread portion of the tire, and side mold portions 12 and 13 that mold the outer surface of the sidewall portion of the tire. . The tread mold portion 11 is composed of a plurality of sectors divided in the tire circumferential direction, and the sectors are gathered together to form an annular shape when the mold is clamped, and are displaced outwardly in the tire radial direction when the mold is opened.

  In such a tire mold, when the mold is opened after vulcanization, the tire is smoothly released from the tread mold part 11, but the tire mold is in close contact with the side mold part 12 or the side mold part 13. It could be difficult. In particular, when the tire is in close contact with the side mold portion 13 disposed above, the tire is lifted as the side mold portion 13 is raised, so that it is necessary for the operator to pull it out manually and the work efficiency is greatly impaired. There was a problem of being.

In order to solve the above problem, in Patent Document 1 below, the upper mold ring is expanded from the outside during vulcanization, and the upper mold ring is lowered at the initial stage of the mold opening operation to remove the tire from the upper mold (upward). A method of peeling from the arranged side mold part) has been proposed. However, this method improves the opening and closing mechanism of the tire mold, and a large modification is inevitable for application to an existing tire mold. In practice, a technique that can be easily applied to existing tire molds is strongly desired.
JP-A-6-218734

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a tire molding method and a tire molding die that can smoothly release a tire from a side mold portion when the mold is opened.

  The above object can be achieved by the present invention as described below. That is, in the tire molding method according to the present invention, the outer surface of the sidewall portion of the tire is brought into contact with the side mold portion, and the outer surface of the tire tread portion is formed into a tread mold portion composed of a combination of sectors divided in the tire circumferential direction. In the tire molding method for vulcanization by contact, when the sector is displaced outward in the tire radial direction after vulcanization, the inner peripheral surface of the sector near the fitting surface with the side mold portion is engaged with the tire. The tire outer surface portion straddling the fitting surface is deformed and peeled off from the side mold portion.

  In the tire molding method of the present invention, by utilizing the sector displacement when the mold is opened after vulcanization, the tire outer surface portion straddling the fitting surface is deformed, and the tire outer surface portion is peeled off from the side mold portion. Like that. By this separation, air enters between the outer surface portion of the tire and the side mold portion in the vicinity of the fitting surface, and a clearance is generated to release the contact state. Therefore, when the side mold part is separated from the tire, the tire can be easily and smoothly released from the side mold part by using the gap as a handle.

  In the above, when the degree of engagement between the inner peripheral surface of the sector and the tire is different from each other on both sides in the circumferential direction of the sector, and when the sector is displaced outward in the tire radial direction after vulcanization, the fitting surface It is preferable to apply a torsional force to the outer surface portion of the tire straddling the tire.

  Thereby, the deformation amount of a tire outer surface part can be enlarged and peeling from a side type | mold part can be accelerated | stimulated. As a result, the contact state between the tire outer surface portion and the side mold portion can be more smoothly released as compared with the case where the deformation of the tire outer surface portion is uniformly expressed on the circumference of the sector.

  In the above, when the degree of engagement between the inner peripheral surface of the sector and the tire is sequentially reduced along the tire circumferential direction, and the sector is displaced outward in the tire radial direction after vulcanization, the fitting is performed. It is preferable to apply a rotational force along the tire circumferential direction to the tire outer surface portion straddling the surface.

  As a result, the ease with which the tire outer surface portion is peeled off from the side mold portion gradually decreases along the tire circumferential direction, so that when the sector is displaced outward in the tire radial direction, the tire outer surface near the fitting surface Peeling of the part from the side mold part is successively expressed along the tire circumferential direction. As a result, the contact state between the tire outer surface portion and the side mold portion can be released more smoothly than in the case where the tire outer surface portion extending in an annular shape is peeled off at once.

  Further, the tire molding die according to the present invention is fitted with a side mold part that molds the outer surface of the sidewall part of the tire and the outer side in the tire radial direction of the side mold part during mold clamping, and molds the outer surface of the tread part of the tire A tread mold part, wherein the tread mold part comprises a combination of sectors divided in the tire circumferential direction, and each of the sectors is configured to be displaceable in the tire radial direction. An engagement element that engages with the tire is provided on the inner peripheral surface in the vicinity of the fitting surface with the side mold portion, and when the sector is displaced outward in the tire radial direction after vulcanization, it straddles the fitting surface. A tire outer surface portion is deformed to be peelable from the side mold portion.

  According to the tire molding die of the present invention, the outer surface portion of the tire straddling the fitting surface can be peeled from the side mold portion by utilizing the displacement of the sector when the mold is opened after vulcanization. By this separation, air enters between the tire outer surface portion and the side mold portion in the vicinity of the fitting surface, and a gap is generated to release the contact state. Therefore, when the side mold part is separated from the tire, the tire can be easily and smoothly released from the side mold part by using the gap as a handle.

  In the present invention, when the engaging element is a convex element protruding to the tire side, it is preferable that a plurality of convex elements are arranged in the sector movement direction. Thereby, the frequency | count of engagement by an engagement element can be increased, a tire outer surface part can be deform | transformed reliably, and this tire outer surface part can be effectively peeled from a side type | mold part. In addition, in this invention, it is possible to employ | adopt the combination of the concave element dented in the anti-tire side other than a convex element, and a convex element and a concave element as an engaging element.

  In the above, it is preferable that the number or size of the engaging elements be different from each other on both sides in the circumferential direction of the sector. According to such a configuration, it is possible to increase the amount of deformation of the tire outer surface portion and promote peeling from the side mold portion. As a result, the contact state between the tire outer surface portion and the side mold portion can be more smoothly released as compared with the case where the deformation of the tire outer surface portion is uniformly expressed on the circumference of the sector. The size of the engaging element includes the width, length, and depth of the engaging element.

  In the above, it is preferable that the number or size of the engaging elements is sequentially reduced for each sector along the tire circumferential direction. According to such a configuration, since the ease of peeling from the side mold portion of the tire outer surface portion decreases in order along the tire circumferential direction, when the sector is displaced outward in the tire radial direction, Thus, the peeling of the tire outer surface portion from the side mold portion is successively expressed along the tire circumferential direction. As a result, the contact state between the tire outer surface portion and the side mold portion can be released more smoothly than in the case where the tire outer surface portion extending in an annular shape is peeled off at once.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view schematically showing an example of a tire mold according to the present invention, showing a clamped state. In FIG. 1, an unvulcanized tire (not shown) is set so that the tire axial direction is up and down, and the right side in FIG. 1 is the inside in the tire radial direction and the left side in FIG. 1 is the outside in the tire radial direction. FIG. 2 is a plan view of the tread mold portion 1.

  The tire mold (hereinafter sometimes simply referred to as “mold”) includes a pair of side mold parts 2 and 3 that mold the outer surface of the sidewall part of the tire, and the side mold parts 2 and 3 during mold clamping. A segmented mold including a tread mold portion 1 that is fitted to the outer side in the tire radial direction and that forms the outer surface of the tread portion of the tire. A bead ring 4 is provided on the inner side in the tire radial direction of the side mold parts 2 and 3 so that the bead part of the tire can be fixed.

  As shown in FIG. 2, the tread mold portion 1 is composed of a combination of sectors 5 divided in the tire circumferential direction, and each sector 5 is configured to be displaceable in the tire radial direction. In the mold-clamped state, the sectors 5 gather near each other, and end surfaces are brought into contact with each other to form an annular shape. In the mold open state, each sector 5 is displaced outward in the tire radial direction and separated from the side mold parts 2 and 3. In the present embodiment, an example is shown in which the tread part 1 is divided into seven and the circumferences of the sectors 5 are substantially equal. However, in the present invention, the number of divisions of the tread part is not particularly limited, and the circumference of each sector is not limited. May be different from each other.

  An example of the material of the tread mold 1 is aluminum. This aluminum is a concept that includes not only pure aluminum materials but also aluminum alloys. For example, Al-Cu, Al-Mg, Al-Mg-Si, Al-Zn-Mg, Al-Mn System and Al-Si system. Moreover, as a material of the side mold parts 2 and 3, a steel material is exemplified.

  A container 21 is attached for each sector 5 on the outer peripheral surface on the back side of the tread mold portion 1. The container 21 is slidably attached along the tire radial direction to the lower surface of a side plate 23 configured to be movable up and down. The cone ring 24 is fitted to a rail 25 provided on the outer slope of the container 21, and is configured to be movable up and down relatively with respect to the side plate 23.

  In the mold clamping state shown in FIG. 1, when the cone ring 24 is raised and the container 21 is moved outward in the tire radial direction, each sector 5 is displaced outward in the tire radial direction and separated from the side mold parts 2 and 3. . When the side plate 23 and the container 21 are further raised, the sector 5 and the side mold part 3 are lifted and the mold is opened. The transition from the mold opening state to the mold clamping state may be performed by reversing the above operation.

  Although not shown in the drawing, a rubber bag called a bladder is installed inside the mold. At the time of vulcanization molding, the outer surface of the tire is pressed against the inner peripheral surfaces of the tread mold part 1 and the side mold parts 2 and 3 by expanding the bladder outward in the tire radial direction. It is also possible to use a rigid core instead of the bladder, and the present invention is applicable to both bladder vulcanization and core vulcanization.

  FIG. 3 is an enlarged view of a main part of the molding die shown in FIG. 1, and shows the periphery (A portion) of the fitting surface 5 a with the side mold part 3 of the sector 5 in an enlarged manner. An engagement element that engages with the tire is provided on the inner peripheral surface of the sector 5 near the fitting surface 5a. In the example of FIG. 3, a protrusion 6 that is a convex element protruding toward the tire side is provided as an engaging element. The mold is configured to be able to be peeled off from the side mold portion 3 by deforming a tire outer surface portion straddling the fitting surface 5a when the sector 5 is displaced outward in the tire radial direction after vulcanization.

  A method of vulcanizing and molding a tire using such a mold is as follows. First, an unvulcanized tire is set in a mold and clamped. Next, the bladder is expanded so that the outer surface of the sidewall portion of the tire is brought into contact with the inner peripheral surfaces of the side mold portions 2 and 3, and the outer surface of the tread portion is brought into contact with the inner peripheral surface of the tread mold portion 1. Then, the mold is heated and held at a predetermined vulcanization temperature, and vulcanization molding is performed on the internal tire. Thereafter, the mold is opened and the vulcanized tire is taken out.

  As described above, in the mold opening operation, first, each sector 5 is displaced outward in the radial direction of the tire and is separated from the side mold parts 2 and 3, and then the sector 5 and the side mold part 3 are raised to form the side mold part. Leave 2 Therefore, the vulcanized tire is first released from the tread mold part 1 and then released from the side mold part 3. In this mold, when the sector 5 is displaced outward in the tire radial direction, the tire outer surface portion straddling the fitting surface 5a and the side mold portion 3 are peeled off, whereby the side mold portion 3 is raised. In addition, the tire can be released easily and smoothly.

  That is, when the sector 5 is displaced outward in the tire radial direction, the inner peripheral surface near the fitting surface 5a of the sector 5 is engaged with the tire T by the protrusion 6, as shown in FIG. The tire outer surface portion Ts straddling 5a is forcibly elastically deformed, and the tire outer surface portion Ts is peeled off from the inner peripheral surface of the side mold portion 3. By this peeling, air enters between the tire outer surface portion Ts and the side mold portion 3, and a gap is generated to release the contact state.

  When the sector 5 is further displaced outward, the engagement is disengaged as shown in FIG. 5, and the tire outer surface portion Ts is restored. However, since the close contact state with the side mold portion 3 has already been released at the tire outer surface portion Ts, a clearance between the tire outer surface portion Ts and the side mold portion 3 is removed when the side mold portion 3 is raised. As a result, the sucker effect by the inner peripheral surface of the side mold part 3 is lost, and the tire T can be released from the side mold part 3 easily and smoothly.

  From the viewpoint of appropriately achieving the above-described effects, the angle θ of the engagement surface 6a of the protrusion 6 with respect to the tire width direction is preferably 30 ° or less. That is, when this angle is 30 ° or less, an engagement force sufficient to deform the tire outer surface portion Ts with the displacement of the sector 5 is ensured satisfactorily.

  The protrusion amount δ of the protrusion 6 in the tire width direction is preferably 0.5 mm or more, and more preferably 1.5 mm or more in order to ensure the engaging action with the tire T. In order to secure the rubber thickness of the tire T at the tire outer surface portion Ts, it is preferable that the protrusion amount δ is 5.0 mm or less. Furthermore, the width W along the tire radial direction of the protrusion 6 is preferably 2 mm or more in order to enhance the durability of the protrusion 6 and prevent a defect.

  The convex elements are not limited to those having a triangular cross-section like the above-described protrusions 6 and may have a shape with rounded tips like the protrusions 7 shown in FIG. According to the projection 7, it is possible to suppress the introduction of cracks to the tire due to the engagement. Examples of the radius of curvature of the tip of the protrusion 7 include 0.5 to 5.0 mm.

  FIG. 7 is a plan view conceptually showing the sector 5 shown in FIG. FIG. 7 shows the outer shape of the protrusion 7. In this sector 5, a plurality of protrusions 7 are arranged in the sector movement direction MD (not necessarily coincident with the tire radial direction). Accordingly, the tire outer surface portion Ts can be reliably deformed by increasing the number of engagements by the protrusions 7, and the tire outer surface portion Ts can be effectively peeled from the side mold portion 3. In this example, the protrusion 7 is provided in a columnar shape, but an engaging element such as the protrusion 7 may be extended along the circumferential direction of the sector 5.

  In the above, an example in which the protrusions 6 and 7 that are convex elements are employed as the engaging elements has been shown. However, in the present invention, in addition to the convex elements, concave elements that are recessed toward the anti-tire side, Combinations can be employed. Therefore, for example, a groove which is a concave element may be provided in place of the protrusion 6 in FIG. 3, and the groove may be engaged with the tire. In the case of a groove, the circumference is preferably 20 mm or more.

  FIG. 8 shows an example in which a combination of a convex element and a concave element is employed as the engaging element. In the sector 5, while providing the protrusions 6 described with reference to FIG. 3, grooves 8 that are concave elements are provided outside the protrusions 6 in the tire radial direction, and a plurality of the grooves 8 are arranged in the moving direction of the sector 5. According to this configuration, the depth of the groove 8 can be added to the height of the protrusion 6 to exert a large engagement force. In addition, since the height of the protrusion 6 can be suppressed while increasing the engagement force, the rubber thickness of the tire T can be ensured and the durability is not impaired.

  The engaging elements such as the protrusions 6 and 7 and the groove 8 are preferably provided within a range of 40 mm or less, more preferably 30 mm or less on the outer side in the tire radial direction from the fitting surface 5a. Thereby, when the inner peripheral surface of the sector 5 is engaged with the tire T by the engagement element, the tire outer surface portion Ts straddling the fitting surface 5a is easily deformed. In general, the fitting surface 5a is located at the buttress portion of the tire T.

  In the example of FIG. 7, the protrusions 7 that are engaging elements are provided uniformly in the circumferential direction of the sector 5, and in this case, the deformation of the outer surface portion of the tire straddling the fitting surface 5 a occurs on the circumference of the sector 5. It tends to be expressed evenly. However, the present invention is not limited to this, and variations such as those shown below can be cited.

  In the sector 5 shown in FIG. 9, the protrusion 9 as the engaging element is disposed only on one side in the circumferential direction (left side in FIG. 9). This is an example in which the number of protrusions 9 is different on both sides in the circumferential direction of the sector 5 so that the degree of engagement between the inner peripheral surface of the sector 5 and the tire is different on both sides in the circumferential direction of the sector 5. .

  In this case, since only the left side in FIG. 9 is engaged with the tire on the inner peripheral surface of the sector 5, only the left side of the tire outer surface portion Ts straddling the fitting surface 5a is pulled, and the tire outer surface portion extending in this arc shape. A clockwise twisting force acts on Ts. Thereby, the deformation amount of the tire outer surface portion Ts increases, and peeling from the side mold portion 3 can be promoted. As a result, the contact state between the tire outer surface portion Ts and the side mold portion can be more smoothly released as compared with the case where the deformation of the tire outer surface portion Ts is uniformly expressed on the circumference of the sector 5.

  In FIG. 9, the number of the protrusions 9 is different on both sides in the circumferential direction of the sector 5, but instead of or in addition to this, the size of the protrusion 9 (width, length, or depth of the protrusion 9) is changed. It is possible. In either case, the sector 5 is configured so that the degree of engagement is different from each other at the circumferential center of the sector 5. FIG. 10 is a modification of the sector 5 shown in FIG. 9, (A) is an example in which discontinuous protrusions 15 are provided on the circumference, and (B) is a cylindrical protrusion 16 on the inner side in the tire radial direction of the protrusion 15. Is an example.

  In the tread mold portion 1 shown in FIG. 11, different numbers of protrusions 17 as engagement elements are provided for each sector 5, whereby the degree of engagement between the inner peripheral surface of the sector 5 and the tire is increased in the tire circumferential direction. It is comprised so that it may become small sequentially along. In the tread mold portion 1, the ease of peeling from the side mold portion of the tire outer surface portion Ts decreases in order along the tire circumferential direction, specifically along the R direction.

  In the tread mold portion 1 described above, when each sector 5 is displaced outward in the tire radial direction, a rotational force acts on the tire outer surface portion Ts straddling the fitting surface 5a along the tire circumferential direction, and the tire outer surface portion. Separation of the Ts from the side mold part is expressed sequentially along the R direction. This is to generate a rotational force locally on the tire outer surface portion Ts to promote peeling, and does not rotate the entire tire, and it is not necessary.

  As a result, the contact state between the tire outer surface portion Ts and the side mold portion can be more smoothly released as compared with the case where the tire outer surface portion Ts extending in an annular shape is peeled at a stretch. Note that the sectors 5 having the same number of protrusions 17 may be locally arranged as long as the above-described effects are obtained. In addition, it is possible not to provide a protrusion in the sector where the degree of engagement is minimum.

  As in the example of FIG. 11, the tread mold portion 1 shown in FIG. 12 has a difference (strength) in the degree of engagement for each sector along the tire circumferential direction. That is, in the tread mold portion 1, the protrusions 18 as the engagement elements are provided with different widths for each sector 5, whereby the degree of engagement between the inner peripheral surface of the sector 5 and the tire is along the tire circumferential direction. It is configured so that it becomes smaller in order. In the example of FIG. 12, the engagement force is adjusted by the width of the protrusion 18, but it can also be adjusted by the length and depth of the protrusion.

  In the above-described embodiment, an example in which the release property of the tire is improved with respect to the side mold part 3 disposed on the upper side has been described. However, the side mold part 2 disposed on the lower side is separated in the same manner as described above. The moldability can be improved. In that case, an engaging element is provided on the inner peripheral surface of the sector 5 near the fitting surface 1b with the side mold portion 2.

  In this invention, you may comprise so that a mold release property may improve with respect to both of a pair of side type | mold parts 2 and 3. FIG. However, since there is usually a clear tendency for the tire to be in close contact with the upper and lower sides, it is sufficient to improve the releasability with respect to one side mold part which is a problem. In addition, when making rotational force act on both side type | mold parts 2 and 3 along a tire circumferential direction like FIG. 11, 12, it is preferable to make the direction of the rotational force the same up and down. .

  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. Therefore, the shape and material of each mold part, their moving mechanism, etc. are not particularly limited, and can be changed as appropriate.

1 is a longitudinal sectional view schematically showing an example of a tire mold according to the present invention. Top view of the tread mold Enlarged view of main parts of tire mold Enlarged view of main parts of tire mold Enlarged view of main parts of tire mold The principal part enlarged view of the tire shaping | molding die which concerns on another embodiment of this invention. Plan view conceptually showing the sector shown in FIG. The principal part enlarged view of the tire shaping | molding die which concerns on another embodiment of this invention. The top view which shows the sector of the tire shaping | molding die concerning another embodiment of this invention. Variation of sector shown in FIG. The top view which shows the tread type | mold part of the tire shaping | molding die concerning another embodiment of this invention. The top view which shows the tread type | mold part of the tire shaping | molding die concerning another embodiment of this invention. Schematic configuration diagram of segmented mold

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tread type | mold part 2 Side type | mold part 3 Side type | mold part 5 Sector 5a Fitting surface 6, 7, 9 Protrusion (convex element as an engagement element)
8 Groove protrusion (concave element as engaging element)
15-18 Protrusions (convex elements as engaging elements)
T Tire Ts Tire outer surface

Claims (7)

In a tire molding method in which an outer surface of a sidewall portion of a tire is brought into contact with a side mold portion, and an outer surface of the tire tread portion is brought into contact with a tread mold portion formed of a combination of sectors divided in a tire circumferential direction to vulcanize the tire. ,
When the sector is displaced outward in the tire radial direction after vulcanization, the inner peripheral surface of the sector near the fitting surface with the side mold portion is engaged with the tire, and the tire outer surface straddling the fitting surface A tire molding method, wherein a portion is deformed and peeled off from the side mold portion.   When the degree of engagement between the inner circumferential surface of the sector and the tire is different from each other on both sides in the circumferential direction of the sector, and when the sector is displaced outward in the tire radial direction after vulcanization, the sector straddles the fitting surface. The tire molding method according to claim 1, wherein a torsional force is applied to the outer portion of the tire.   When the degree of engagement between the inner peripheral surface of the sector and the tire is reduced in order along the tire circumferential direction, and the sector is displaced outward in the tire radial direction after vulcanization, the sector straddles the fitting surface. The tire molding method according to claim 1, wherein a rotational force is applied to the tire outer surface portion along the tire circumferential direction. The tread mold includes: a side mold part that molds an outer surface of a sidewall part of a tire; and a tread mold part that is fitted to the outer side in the tire radial direction of the side mold part when the mold is clamped to mold the outer surface of the tread part of the tire. In the tire mold in which the portion is composed of a combination of sectors divided in the tire circumferential direction, and each of the sectors is configured to be displaceable in the tire radial direction,
An engagement element that engages with a tire is provided on the inner peripheral surface of the sector in the vicinity of the fitting surface with the side mold portion, and when the sector is displaced outward in the tire radial direction after vulcanization, the sector straddles the fitting surface. A tire molding die characterized in that the outer surface portion of the tire is deformed so as to be peelable from the side mold portion.   The tire molding die according to claim 4, wherein the engagement element is a convex element protruding toward the tire side, and a plurality of the convex elements are arranged in a moving direction of the sector.   The tire molding die according to claim 4 or 5, wherein the number or size of the engagement elements are different from each other on both sides in the circumferential direction of the sector.   The tire mold according to any one of claims 4 to 6, wherein the number or size of the engaging elements is sequentially reduced for each sector along the tire circumferential direction.

Images