JP2007210248A - Mold for vulcanizing tire and pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold for vulcanizing tires capable of improving a production efficiency while restraining the occurrence of the swollen-out rubber and provide pneumatic tires manufactured with this mold for vulcanizing tires. <P>SOLUTION: The mold 1 for vulcanizing tires is equipped with a pair of the side molds 3 having side inner peripheral surfaces 3a and the sector mold 5 having the sector inner peripheral surface 5a. The side molds 3 have the side notches 9 on the sides of the side inner peripheral surfaces 3a in the side contact surfaces 3b, the side notches 9 curve from the side intersections 11 towards the side inner peripheral surfaces 3a, and the side notch angle (α1) is an obtuse angle. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention includes a pair of side molds and a sector mold, and a tire vulcanization mold in which a vulcanized space for storing an unvulcanized tire is formed inside when the side mold and the sector mold are in close contact with each other, and The present invention also relates to a pneumatic tire manufactured by the tire vulcanization mold.

  Conventionally, it has an inner peripheral surface that forms a side portion of a pneumatic tire, has a pair of side molds that form a disk shape, and an inner peripheral surface that forms a tread portion of the pneumatic tire, and is movable in the radial direction. A tire vulcanization mold called a split mold including a sector mold composed of a plurality of arc-shaped segments is known (for example, see Patent Document 1).

  When unvulcanized tires (so-called green tires and green tires) are vulcanized and molded using this tire vulcanizing mold, the unvulcanized tires are placed on one side mold (side mold located below). After placing, the other side mold (side mold located above) moves toward the unvulcanized tire, and the sector mold moves toward the unvulcanized tire.

When the arc-shaped segments move to the inner limit in the radial direction, the segments are brought into close contact with each other to form a ring shape. At this time, the sector mold and the pair of side molds are in close contact with each other, and the unvulcanized tire is stored in the interior (vulcanized space). Thereafter, the unvulcanized tire is vulcanized while being pressed against the side inner peripheral surface of the pair of side molds and the sector inner peripheral surface of the sector mold by a bladder, whereby a pneumatic tire is manufactured.
Japanese Examined Patent Publication No. 6-45137 (pages 1 to 3 and FIG. 1)

  However, as shown in FIG. 14, in the conventional tire vulcanization mold 100, the side inner peripheral surfaces 101 a of the pair of side molds 101 (the side molds positioned below in FIG. 14) and the pair of side molds 101. The intersection 101c intersecting with the side contact surface 101b with respect to the sector mold 103 is angular (sharp), or a small-diameter arc-shaped chamfer is applied.

  Therefore, when the unvulcanized tire 200 is in the radial direction while being in contact with the intersecting portion 101c, a part of the rubber constituting the unvulcanized tire 200 is scraped off by the intersecting portion 101c and the side contact surface 101b. The sector mold 103 penetrates between the side mold 101 and the sector contact surface 103a.

  Part of the rubber constituting the unvulcanized tire 200 that has entered between the side contact surface 101b of the side mold 101 and the sector contact surface 103a of the sector mold 103 is crushed by both contact surfaces, and is in the form of a film. It becomes a large protruding rubber (so-called flash is generated).

  Accordingly, a pneumatic tire having a large protruding rubber is produced, and although this protruding rubber can be cut off to some extent, it is often difficult to cut it in consideration of the product performance. In addition, since the appearance of a pneumatic tire having a large protruding rubber is remarkably deteriorated, a process for cutting out the protruding rubber is required, which complicates the work and decreases the production efficiency.

  Accordingly, the present invention provides a tire vulcanization mold capable of improving the production efficiency while suppressing the occurrence of protruding rubber, and a pneumatic tire manufactured using the tire vulcanization mold. With the goal.

  In order to solve the above-described problems, the present invention has the following features. First, as a first feature of the present invention, a pair of side molds having a side inner peripheral surface forming a side portion of a pneumatic tire and forming a disk shape, and a sector inner periphery forming a tread portion of the pneumatic tire A mold for vulcanizing a tire having a surface and a sector mold composed of a plurality of arc-shaped segments movable in a radial direction, wherein the side mold has a side inner periphery on a side contact surface with respect to the sector mold. There is a side notch on the surface side, and the side notch is curved from the side intersection where it intersects the side contact surface toward the side inner periphery, and faces toward the side inner periphery. The side notch angle, which is the angle formed between the side bend portion and the side notch straight line connecting from the intersection of the side inner peripheral surface to the side intersection, and the side inner peripheral surface is dull. And summary that is.

  According to this feature, the side notch portion in the side mold is curved from the side crossing portion toward the side inner peripheral surface, and the side notch angle is an obtuse angle. Since the portion can be prevented from entering between the side contact surface and the sector contact surface, the occurrence of the protruding rubber can be suppressed.

  Along with suppressing the occurrence of the protruding rubber, a pneumatic tire having the protruding rubber is not manufactured, so that the appearance can be prevented from being significantly deteriorated. In addition, since it is possible to easily open and close the side mold and the sector mold without requiring a step of cutting off the protruding rubber, the production efficiency can be improved.

  As a second feature of the present invention, the sector mold has a sector notch portion on the sector inner peripheral surface side of the sector contact surface with respect to the side mold, and the sector notch portion intersects with the sector contact surface. Curved from a sector crossing point toward the sector inner peripheral surface, a sector curved portion that curves toward the sector inner peripheral surface, and a sector notch straight line connecting from the intersection of the sector inner peripheral surface to the sector crossing point The gist of the sector notch angle, which is the angle formed with the inner circumferential surface of the sector, is an obtuse angle.

  According to such a feature, the sector notch in the sector mold is curved from the sector intersection to the sector inner peripheral surface, and the sector notch angle is an obtuse angle. Since it is possible to further prevent the portion from entering between the side contact surface and the sector contact surface, it is possible to further improve the production efficiency while further suppressing the occurrence of the protruding rubber.

  As a third feature of the present invention, an orthogonal distance, which is a distance orthogonal to a tangent line connecting a side inner peripheral surface and a sector inner peripheral surface, from a side intersection or sector intersection is 2.0 to 5.0 mm. It is a summary.

  If the orthogonal distance is shorter than 2.0 mm, it may not be possible to prevent a part of the rubber constituting the unvulcanized tire from entering between the side contact surface and the sector contact surface. In some cases, protruding rubber may be generated.

  Also, if the orthogonal distance is longer than 5.0 mm, the amount of rubber constituting the unvulcanized tire may not be enough to fill the side notch or sector notch, which may cause bears and the like. It may become.

  A fourth feature of the present invention is that the side curvature radius of the side curved portion or the sector curvature radius of the sector curved portion is 5 to 30 mm.

  In addition, if the side curvature radius or the sector curvature radius is smaller than 5 mm, the pneumatic tire manufactured by vulcanizing the unvulcanized tire may be wrinkled, causing cracks and the like. May end up.

  Moreover, when the side curvature radius or the sector curvature radius is larger than 30 mm, it is impossible to prevent a part of the rubber constituting the unvulcanized tire from entering between the side contact surface and the sector contact surface. In some cases, protruding rubber may be generated.

  A fifth feature of the present invention is that the tire is manufactured by the tire vulcanization mold according to any one of the first to fourth aspects.

  According to the present invention, the side notch portion in the side mold is curved from the side intersection portion toward the side inner peripheral surface, and the side notch angle is an obtuse angle, whereby one of the rubbers constituting the unvulcanized tire. Tire can be prevented from entering between the side contact surface and the sector contact surface, and the tire vulcanization mold that can improve the production efficiency while suppressing the occurrence of protruding rubber, And the pneumatic tire shape | molded by this metal mold | die for tire vulcanization | cure can be provided.

  Next, an example of a tire vulcanization mold according to the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  FIG. 1 is a cross-sectional view showing a side mold and a sector mold constituting a tire vulcanization mold according to the present embodiment, and FIG. 2 is a side mold of the tire vulcanization mold according to the present embodiment (see FIG. 1 is an enlarged cross-sectional view showing a part of a side mold) and a sector mold positioned downward in FIG.

  As shown in FIG. 1, the tire vulcanization mold 1 includes a pair of side molds 3 and a sector mold 5. The tire vulcanizing mold 1 is used when a pneumatic tire 50 (see FIG. 3) is manufactured.

  Further, the tire vulcanization mold 1 is formed with a vulcanization space 7 for storing the unvulcanized tire 63 therein when the pair of side molds 3 and the sector mold 5 are in close contact with each other. The unvulcanized tire 63 (the carcass layer 53 and the belt layer 55 are omitted) is vulcanized while being pressed against the tire vulcanizing mold 1 by the bladder B, whereby the pneumatic tire 50 is manufactured.

  The pair of side molds 3 have side inner peripheral surfaces 3a that form the side portions 57 (see FIG. 3) of the pneumatic tire 50, and have a disk shape. The pair of side molds 3 have side cutout portions 9 on the side inner peripheral surface 3 a side of the side contact surface 3 b with respect to the sector mold 5.

  Specifically, as shown in FIG. 2, the side notch portion 9 is curved toward the side inner peripheral surface 3 a from the side intersection portion 11 that is an intersection portion with the side contact surface 3 b. The angle formed by the side inner peripheral surface 3a and the side notch straight line SL1 that connects the side curved portion 13 that curves toward the side inner peripheral surface 3a and the intersection of the side inner peripheral surface 3a to the side intersection 11 and the side inner peripheral surface 3a. A certain side notch angle (α1) is an obtuse angle.

  The sector mold 5 has a sector inner peripheral surface 5a that forms a tread portion 59 (see FIG. 3) of the pneumatic tire 50, and is composed of a plurality of arc-shaped segments that are movable in the radial direction. The sector mold 5 has a sector notch 15 on the side of the sector inner peripheral surface 5 a in the sector contact surface 5 b with respect to the side mold 3.

  Specifically, as shown in FIG. 2, the sector cutout portion 15 is curved from the sector intersection 17 that is an intersection with the sector contact surface 5 b toward the sector inner circumferential surface 5 a. An angle formed between the sector curved portion 19 that is curved toward the sector inner peripheral surface 5a and the sector cut-out straight line SL2 that connects from the intersection of the sector inner peripheral surface 5a to the sector intersection 17 and the sector inner peripheral surface 5a. A certain sector notch angle (α2) is an obtuse angle.

  Here, an orthogonal distance (D), which is a distance orthogonal to the tangent line T connecting the side inner peripheral surface 3a and the sector inner peripheral surface 5a from the side crossing point 11 or the sector crossing point 17 described above, is 2.0. It is preferable that it is -5.0mm, and it is more preferable that it is 3.0-4.0mm.

  If the orthogonal distance (D) is shorter than 2.0 mm, a part of the rubber constituting the unvulcanized tire 63 is prevented from entering between the side contact surface 3b and the sector contact surface 5b. May not be able to occur, and the protruding rubber may be generated.

  Further, if the orthogonal distance (D) is longer than 5.0 mm, the amount of rubber constituting the unvulcanized tire 63 may be insufficient to fill the side notches 9 and the sector notches 15. Or the like may occur.

  Furthermore, the above-described side curvature radius (Ra) of the side curved portion 13 or the sector curvature radius (Rb) of the sector curved portion 19 is preferably 5 to 30 mm, and more preferably 10 to 20 mm. In particular, the side curvature radius (Ra) and the sector curvature radius (Rb) are preferably 5 to 30 mm, and more preferably 10 to 20 mm.

  If the side curvature radius (Ra) or the sector curvature radius (Rb) is smaller than 5 mm, the pneumatic tire 50 produced by vulcanizing the unvulcanized tire 63 may be wrinkled, and cracks may occur. Or the like may occur.

  Further, when the side curvature radius (Ra) or the sector curvature radius (Rb) is larger than 30 mm, a part of the rubber constituting the unvulcanized tire 63 enters between the side contact surface 3b and the sector contact surface 5b. In some cases, it is not possible to prevent the rubber from protruding.

  Next, the pneumatic tire manufactured by the tire vulcanization mold described above will be described with reference to the drawings. FIG. 3 is a cross-sectional view in the tread width direction showing the pneumatic tire (one side of the tire equator line CL) according to the present embodiment.

  As shown in FIG. 3, the pneumatic tire 50 manufactured by the tire vulcanization mold 1 is a general radial tire including a bead portion 51, a carcass layer 53, and a belt layer 55. This pneumatic tire 50 includes a side part 57 formed by a pair of side molds 3 constituting the tire vulcanizing mold 1 and a tread part formed by a sector mold 5 constituting the tire vulcanizing mold 1. 59 is further provided.

  Further, the pneumatic tire 50 has a protruding portion 61 formed by the side notch portions 9 of the pair of side molds 3 and the sector notch portion 15 of the sector mold 5. The protrusion 61 has substantially the same shape as the side notch 9 of the pair of side molds 3 and the sector notch 15 of the sector mold 5.

  That is, the protrusion 61 has a protrusion amount (D ′) corresponding to the orthogonal distance (D), a curvature radius (Ra ′) on the bead portion side corresponding to the side curvature radius (Ra), and a sector curvature radius ( The radius of curvature (Rb ′) on the tread portion side corresponding to Rb).

  For this reason, the protrusion amount (D ′) of the protrusion 61 is preferably 2.0 to 5.0 mm, and particularly preferably 3.0 to 4.0 mm. Further, the radius of curvature (Ra ') on the bead portion side or the radius of curvature (Rb') on the tread portion side is preferably 5 to 30 mm, and particularly preferably 10 to 20 mm.

(Action / Effect)
As described above, according to the tire vulcanization mold 1 described above, the side notch portions 9 in the pair of side molds 3 are curved from the side intersection portion 11 toward the side inner peripheral surface 3a, and the side notches. Since the angle (α1) is an obtuse angle, it is possible to prevent a part of the rubber constituting the unvulcanized tire 63 from entering between the side contact surface 3b and the sector contact surface 5b. The occurrence of protruding rubber can be suppressed. According to the pneumatic tire 50 manufactured by the tire vulcanization mold, the appearance is not significantly deteriorated without having the protruding rubber.

  Along with suppressing the occurrence of the protruding rubber, the pneumatic tire 50 having the protruding rubber is not manufactured, so that the appearance can be prevented from being significantly deteriorated. Further, since it is possible to easily open and close the side mold 3 and the sector mold 5 without requiring a process of cutting off the protruding rubber, it is possible to improve the production efficiency.

  The sector notch 15 in the sector mold 5 is curved from the sector crossing point 17 toward the sector inner peripheral surface 5a, and the sector notch angle (α2) is an obtuse angle, whereby the unvulcanized tire 63 is configured. Since it is possible to further prevent a part of the rubber to enter between the side contact surface 3b and the sector contact surface 5b, the production efficiency is further improved while further suppressing the occurrence of the protruding rubber. Can do.

[Other Embodiments]
Although the contents of the present invention have been disclosed through the embodiments of the present invention as described above, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention.

  Specifically, in the tire vulcanization mold 1 according to the present embodiment, the side crossing portion 11 and the sector crossing portion 17 shown in FIG. Of course, it may be chamfered.

  Moreover, although the pneumatic tire 50 which concerns on this embodiment demonstrated as what is a radial tire, it is not limited to this, Tires (for example, bias tire) other than a radial tire may be sufficient.

  From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

Next, in order to further clarify the effects of the present invention, the results of tests performed using pneumatic tires according to the following Comparative Examples 1 to 3 and Examples 1 to 4 will be described. The pneumatic tires according to Comparative Examples 1 to 3 and Examples 1 to 4 have a tire size of “245 / 70R17.5” and a wheel size of “7.50”. The pneumatic tires according to Comparative Examples 1 to 3 and Examples 1 to 4 will be described with reference to Table 1 and the drawings.

  The pneumatic tire according to Comparative Example 1 is manufactured by the tire vulcanization mold shown in FIG. 4 and has the protrusions shown in Table 1. Further, the pneumatic tire according to Comparative Example 2 is manufactured by the tire vulcanization mold shown in FIG. 5 and has the protrusions shown in Table 1. Furthermore, the pneumatic tire according to Comparative Example 3 is manufactured by a tire vulcanization mold shown in FIG. 6 and has a protrusion 61 shown in Table 1.

  The pneumatic tire according to Example 1 is manufactured by the tire vulcanization mold shown in FIG. 7 and has the protrusions shown in Table 1. The pneumatic tire according to Example 2 is manufactured by the tire vulcanization mold shown in FIG. 8 and has the protrusions shown in Table 1. Further, the pneumatic tire according to Example 3 is manufactured by the tire vulcanization mold shown in FIG. 9 and has the protrusions shown in Table 1. Furthermore, the pneumatic tire according to Example 4 is manufactured by the tire vulcanization mold shown in FIG. 10 and has the protrusions shown in Table 1.

The pneumatic tires according to Comparative Examples 1 to 3 and Examples 1 to 4 will be described with reference to Table 2.

<Generation of protruding rubber>
At the time of DEF after vulcanization of each pneumatic tire (a state before the normal internal pressure is filled), it was measured whether or not the protruding rubber was generated under the conditions of the internal pressure “100 kpa” and the load “0 kN”. .

  As a result, it was found that the pneumatic tires according to Examples 1, 2, and 4 did not generate protruding rubber. In addition, it was found that the pneumatic tire according to Example 3 had a smaller protruding rubber than the pneumatic tires according to Comparative Examples 1 and 2.

  That is, as shown in FIG. 11, in the tire vulcanization mold, when the orthogonal distance is shorter than 2.0 mm, a rubber tire with a large protruding rubber is produced, and conversely, the orthogonal distance is more than 3.0 mm. If the length is too long, it has been found that a pneumatic tire without protruding rubber can be produced.

  In addition, as shown in FIG. 12, in the tire vulcanization mold, when the radius of curvature is small, a pneumatic tire having no protruding rubber can be manufactured. Conversely, when the radius of curvature is too large, the tire protrudes. It has been found that it will produce pneumatic tires with rubber.

<Bear generation>
At the time of DEF after vulcanization of each pneumatic tire, it was measured whether or not bear was generated under the conditions of an internal pressure of “100 kpa” and a load of “0 kN”.

  As a result, it was found that the pneumatic tires according to Examples 1 to 3 did not generate bears. In addition, it was found that the pneumatic tire according to Example 4 is slightly bare. That is, in a tire vulcanization mold, a pneumatic tire that does not generate a bear can be manufactured when the orthogonal distance is short, and conversely, a pneumatic tire that generates a bear when the orthogonal distance is long. It turns out that will produce.

<Occurrence of wrinkles>
Each pneumatic tire was measured for whether or not wrinkles were generated under conditions of an internal pressure of “850 kpa” and a load of “2575 kN”.

  As a result, it was found that the pneumatic tires according to Examples 1 to 4 did not generate wrinkles. That is, as shown in FIG. 13, in the tire vulcanization mold, it was found that when the side curvature radius or the sector curvature radius is smaller than 5 mm, a pneumatic tire in which wrinkles are generated is produced.

<Comprehensive evaluation>
Thus, in a pneumatic tire, when the protrusion amount (D ′) is shorter than 2.0 mm, the protruding rubber is likely to be generated, and when the protrusion amount (D ′) is too long, a bear is likely to be generated. Further, in the pneumatic tire, if the radius of curvature (Ra ′) or the radius of curvature (Rb ′) is smaller than 5 mm, wrinkles are likely to occur, and the radius of curvature (Ra ′) or the radius of curvature (Rb ′) is larger than 30 mm. If it is large, the protruding rubber is likely to be generated.

  For this reason, the pneumatic tire which concerns on Examples 1-4 manufactured with the metal mold | die for tire vulcanization to which this invention was applied compared with the pneumatic tire which concerns on Comparative Examples 1-3 generate | occur | produces a protrusion rubber and a bear. It was difficult and no wrinkles were found.

It is sectional drawing which shows the side mold and sector mold which comprise the metal mold | die for tire vulcanization | cure which concerns on this embodiment. It is an expanded sectional view which shows a part of side mold (side mold located in FIG. 1 below) and a sector mold of the tire vulcanization mold according to this embodiment. It is a tread width direction sectional view showing a pneumatic tire concerning this embodiment. It is an expanded sectional view showing a part of a side mold and a sector mold of a tire vulcanization mold concerning comparative example 1. It is an expanded sectional view showing a part of a side mold and a sector mold of a tire vulcanization mold concerning comparative example 2. The expanded sectional view which shows a part of side mold and sector mold of the tire vulcanization mold according to Comparative Example 3. It is an expanded sectional view showing a part of a side mold and a sector mold of a tire vulcanization mold concerning Example 1. It is an expanded sectional view showing a part of a side mold and a sector mold of a tire vulcanization mold concerning Example 2. It is an expanded sectional view showing a part of a side mold and a sector mold of a tire vulcanization mold concerning Example 3. It is an expanded sectional view showing a part of a side mold and a sector mold of a tire vulcanization mold concerning Example 4. It is a graph which shows whether the protrusion rubber | gum generate | occur | produces in an Example. It is a graph which shows whether the protrusion rubber | gum generate | occur | produces in an Example. It is a graph which shows whether wrinkles generate | occur | produce in an Example. It is an expanded sectional view which shows a part of side mold of the conventional metal mold | die for tire vulcanization, and a sector mold.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Mold for tire vulcanization, 3 ... Side mold, 3a ... Side inner peripheral surface, 3b ... Side contact surface, 5 ... Sector mold, 5a ... Sector inner peripheral surface, 5b ... Sector contact surface, 7 ... Vulcanization space , 9 ... Side cut-out part, 11 ... Side crossing part, 13 ... Side curved part, 15 ... Sector notch part, 17 ... Sector crossing part, 19 ... Sector curved part, 50 ... Pneumatic tire, 51 ... Bead part, 53 ... carcass layer, 55 ... belt layer, 57 ... side portion, 59 ... tread portion, 61 ... projection, 63 ... unvulcanized tire, 100 ... mold for tire vulcanization, 101 ... side mold, 101a ... inside side Peripheral surface, 101b ... side contact surface, 101c ... intersection, 103 ... sector mold, 103a ... sector contact surface, 200 ... unvulcanized tire, B ... bladder, T ... tangent

Claims (5)

It has a side inner peripheral surface that forms the side portion of the pneumatic tire, a pair of side molds that form a disk shape, and a sector inner peripheral surface that forms the tread portion of the pneumatic tire, and is movable in the radial direction A mold for tire vulcanization comprising a sector mold composed of a plurality of arc-shaped segments,
The side mold has a side notch on the side inner peripheral surface side in the side contact surface with respect to the sector mold,
The side notch is curved from a side intersection location that is an intersection location with the side contact surface toward the side inner peripheral surface,
The side cut portion that is an angle formed by the side curved portion that curves toward the side inner peripheral surface and the side notch straight line that connects from the intersection of the side inner peripheral surface to the side intersection, and the side inner peripheral surface. Tire vulcanization mold characterized in that the notch angle is an obtuse angle. The sector mold has a sector cutout portion on the sector inner peripheral surface side in the sector contact surface with respect to the side mold,
The sector notch is curved from the sector crossing point that is the crossing point with the sector contact surface toward the sector inner peripheral surface,
A sector cut which is an angle formed between a sector curved portion curved toward the sector inner peripheral surface and a sector notch straight line connecting from the intersection of the sector inner peripheral surface to the sector intersection and the sector inner peripheral surface. 2. The tire vulcanization mold according to claim 1, wherein the notch angle is an obtuse angle.   An orthogonal distance, which is a distance orthogonal to the tangent line connecting the side inner peripheral surface and the sector inner peripheral surface from the side intersection or the sector intersection, is 2.0 to 5.0 mm. The tire vulcanization mold according to claim 1 or 2.   The side curvature radius of the side curved portion or the sector curvature radius of the sector curved portion is 5 to 30 mm, for tire vulcanization according to any one of claims 1 to 3. Mold.   A pneumatic tire manufactured by the tire vulcanization mold according to any one of claims 1 to 4.

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