JP2008001353A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire whose sign formed on a side wall section of the tire has improved visibility and where a vulcanization failure caused by air traps occurring in forming the sign is reduced. <P>SOLUTION: Two circumferential ridges 9 extending in the circumferential direction of the tire are arranged on a surface 2a of the side wall section 2 with a predetermined interval in the radial direction of the tire. At least two radial ridges 10 connected to the two circumferential ridges 9 and extending in the radial direction of the tire are arranged with a predetermined interval in the circumferential direction. A region defined by the circumferential ridges 9 and the radial ridges 10 is formed in a recessed surface 11 recessed in the surface 2a of the side wall section 2. At least one sign 8 projecting from the surface 2a of the side wall section 2 is provided on the recessed surface 11. The height H1 of the sign 8 from the surface 2a of the side wall section 2 is not more than the height H2 of the circumferential ridges 9 from the surface 2a of the side wall section 2 and the height H3 of the radial ridges 10 from the surface 2a of the side wall section 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pneumatic tire. More specifically, the present invention relates to a pneumatic tire that enhances the visibility of a sign formed on a sidewall portion and reduces a vulcanization failure due to an air pocket during sign molding.

  In order to display the manufacturer name, brand name, and the like on the surface of the sidewall portion of the tire, a sign made of characters, figures, symbols, and the like is projected from the surface of the sidewall portion. Conventionally, in such a sign, the protruding height of the sign has been increased as much as possible in order to improve the visibility of the sign. However, if the protruding height of the marker is increased, an air pocket is generated due to poor rubber flow at the time of marker molding, resulting in a problem of vulcanization failure.

  Conventionally, as a countermeasure, the form of the sign formed on the side wall is devised to improve the visibility of the sign, improve the rubber flow failure during sign molding, and reduce the vulcanization failure caused by air traps. Various proposals have been made (see, for example, Patent Documents 1 and 2).

However, in any proposal, it is still inadequate as a countermeasure to achieve the trade-off between improving the visibility of the sign and preventing vulcanization failure due to poor rubber flow, and there is still room for improvement. .
JP-A-6-55915 JP-A-10-67208

  An object of the present invention is to provide a pneumatic tire capable of improving the visibility of a sign formed on a sidewall portion and reducing vulcanization failure due to an air pocket during sign molding.

  In the pneumatic tire of the present invention that achieves the above object, two circumferential protrusions extending in the tire circumferential direction are arranged on the surface of the sidewall portion at a predetermined interval in the tire radial direction, and the two circumferential directions are arranged. Between the projections, at least two radial projections connected to the two circumferential projections and extending in the tire radial direction are arranged at predetermined intervals in the tire circumferential direction, and the circumferential projection and the radial projection A region partitioned by the surface of the sidewall portion is formed on a recessed surface that is recessed from the surface of the sidewall portion, and at least one mark protruding from the surface of the sidewall portion is provided on the recessed surface, and the height of the mark from the surface of the sidewall portion is increased. The height is set to be equal to or less than the height of the circumferential protrusion from the surface of the sidewall portion and the height of the radial protrusion from the surface of the sidewall portion.

  According to the present invention described above, a circumferential protrusion and a radial protrusion connected to the circumferential protrusion are provided on the surface of the sidewall portion, and an area defined by the circumferential protrusion and the radial protrusion is formed on the recessed surface. By forming a sign projecting from the surface of the side wall part on the recessed surface, and further defining the height of the sign as described above, between the sign and the concave part of the mold for molding it during tire vulcanization The air remaining in the tire can be effectively escaped to the groove of the mold for molding the circumferential protrusion and the radial protrusion through the space between the hollow surface recessed inside the tire and the inner surface of the mold. It is possible to improve the vulcanization failure due to air accumulation at the time.

  On the other hand, the surface of the sidewall part protrudes from the surface of the sidewall part from the recessed surface recessed inside the tire in a state surrounded by the circumferential protrusion and the radial protrusion protruding from the surface of the sidewall part. Therefore, the visibility of the sign can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  In FIG. 1, 1 is a tread portion, 2 is a sidewall portion, 3 is a bead portion, and 100 is a tire equatorial plane. A carcass layer 4 in which reinforcing cords extending in the tire radial direction are arranged between the left and right bead portions 3 at predetermined intervals in the tire circumferential direction and embedded in the rubber layer is extended, and both end portions 4a thereof are connected to the bead portion 3. The bead filler 6 is sandwiched around the buried bead core 5 and folded back from the inner side to the outer side in the tire axial direction. On the outer peripheral side of the carcass layer 4 of the tread portion 1, a plurality of belt layers 7 are provided in which reinforcing cords such as steel cords that are inclined with respect to the tire circumferential direction are embedded in the rubber layer.

  On the surface 2a of the sidewall portion 2, the tire cross section is positioned at a distance of 1/4 of the tire cross section height SH from the tire maximum width position P1 to the inside in the tire radial direction, and from the tire maximum width position P1 to the tire radial direction outside. A region Y where a convex marker 8 made up of characters, symbols, figures and the like is formed is located between the height SH and a position separated by a length of ¼.

  In the region Y, as shown in FIG. 2, two circumferential protrusions 9 (9A, 9B) extending annularly along the tire circumferential direction are provided on the surface of the sidewall portion 2 at a predetermined interval in the tire radial direction. 2a. In the region Y, the surface of the sidewall portion 2 further extends in the tire radial direction and has at least two radial projections 10 connected to the two circumferential projections 9A and 9B at a predetermined interval in the tire circumferential direction. 2a. Regions defined by the circumferential protrusions 9A and 9B and the radial protrusions 10 are formed in a recessed surface 11 that is recessed by a depth D from the surface 2a of the sidewall portion 2, as shown in FIGS. A marker 8 protrudes from the surface 2 a of the sidewall portion 2 on the recessed surface 11.

  The height H1 of the marker 8 from the surface 2a of the sidewall portion 2 is equal to or less than the height H2 of the circumferential protrusions 9A and 9B from the surface 2a of the sidewall portion 2, and from the surface 2a of the sidewall portion 2. The height of the radial protrusion 10 is equal to or less than H3.

  Thereby, at the time of tire vulcanization, as shown in FIG. 5, the unvulcanized rubber 12 constituting the sidewall portion 2 first comes into contact with the convex surface 24 of the mold 20 that molds the recessed surface 11. Next, as shown in FIG. 6, the unvulcanized rubber 12 first flows into the marker molding recess 21 of the mold 20, and then flows into the groove 22 of the mold 20 for molding the circumferential protrusion 9 and the radial protrusion 10. . As shown in FIG. 7, since the unvulcanized rubber 12 flows into the bottom of the marker molding recess 21 of the mold 20, the air remaining between the unvulcanized rubber 12 and the wall surface of the marker molding recess 21. Is extruded by the unvulcanized rubber 12 that has flowed in, and passes through between the convex surface 24 of the mold 20 and the portion of the unvulcanized rubber 12 that forms the recessed surface 11 as indicated by the arrows. It escapes to the groove 22 of the mold 20 partially filled with the rubber 12. Therefore, the vulcanization failure due to the air pool during the molding of the sign 8 is reduced. The air that has escaped into the groove 22 of the mold 20 is discharged to the outside through the vent hole 23 for venting air.

  According to the present invention described above, the tire 8 is surrounded by the circumferential protrusions 9A and 9B and the radial protrusions 10 protruding from the surface 2a of the sidewall part 2 on the surface 2a of the sidewall part 2. Since it forms in the form which protruded from the surface 2a of the side wall part 2 from the hollow surface 11 dented inside, the visibility of the label | marker 8 can be improved.

  Further, by providing the mark 8 on the recessed surface 11 and defining the height H1 thereof with respect to the height H2 of the circumferential projections 9A and 9B and the height H3 of the radial projection 10 as described above, It is possible to improve the rubber flow at the time of marker molding and to improve the vulcanization failure due to air accumulation.

  If the height H1 of the marker 8 is higher than the height H2 of the circumferential protrusions 9A and 9B, air trapping is likely to occur during marker molding. The same applies when the height H1 of the marker 8 is higher than the height H3 of the radial protrusion 10. Preferably, the height H1 of the marker 8 is lower than the height H2 of the circumferential protrusions 9A and 9B and the height H3 of the radial protrusion 10.

  In the present invention, when the marker 8 has an annular protrusion 8m and a portion 8n surrounded by the annular protrusion 8m as shown by “O” on the right side of FIG. 2, the portion 8n is moved to the side as shown in FIG. It is preferable that the height be higher than the surface 2 a of the wall portion 2. Thus, during tire vulcanization, as shown in FIG. 9, the air in the mark molding recess 21 of the mold 20 is not added to form the convex surface 24 and the recessed surface 11 of the mold 20 as indicated by arrows. It is possible to make it easy to escape to the groove 22 of the mold 20 for molding the circumferential protrusion 9 and the radial protrusion 10 into which the unvulcanized rubber 12 has partially flowed through the portion of the vulcanized rubber 12. .

  The height Hn of the portion 8n only needs to be higher than the surface 2a of the sidewall portion 2. The upper limit value of the height Hn of the portion 8n is preferably 0.25 times or less the height H1 of the sign 8 from the viewpoint of the visibility of the sign 8.

  FIG. 10 shows another embodiment of the pneumatic tire of the present invention and partially shows the sign 8 formed on the surface 2 a of the sidewall portion 2. In the embodiment of FIG. 10, a plurality of auxiliary protrusions extending along the tire radial direction in addition to the above-described mark 8 on the recessed surface 11 of the region defined by the circumferential protrusions 9 </ b> A and 9 </ b> B and the radial protrusion 10. 13 are formed at predetermined intervals in the tire circumferential direction. The plurality of auxiliary projections 13 includes a first auxiliary projection 13A having one end connected to the mark 8 and the other end connected to the circumferential projection 9 and a second auxiliary projection 13B having both ends connected to the circumferential projections 9A and 9B. It is configured. As shown in FIG. 11, the auxiliary protrusion 13 has a height H4, and the ratio H4 / D between the height H and the depth D of the recessed surface 11 is 0.6 ≦ H4 / D ≦ 1.0. The relationship expressed by is satisfied.

  By connecting the mark 8 to the circumferential protrusion 9 via the first auxiliary protrusion 13A in this way, the air remaining between the mark 8 and the wall surface of the mark forming recess is formed into the first auxiliary protrusion 13A. It can escape to the groove | channel of the metal mold | die which shape | molds the circumferential direction protrusion through the groove | channel of a metal mold | die. Further, the second auxiliary protrusion 13B having both ends connected to the circumferential protrusions 9A and 9B allows the air remaining on the recessed surface 11 and the inner surface of the mold to be efficiently passed through the groove of the mold for molding the second auxiliary protrusion 13. The circumferential projections 9A and 9B can be well escaped to the mold groove. Therefore, the vulcanization failure due to the accumulation of air at the time of marker molding can be further improved.

  When the ratio H4 / D is smaller than 0.6, the groove of the mold for molding the auxiliary protrusion 13 is too shallow, and the remaining air cannot be effectively released. When the ratio H4 / D exceeds 1.0, the visibility of the label 8 is lowered.

  As described above, it is preferable to provide a plurality of auxiliary projections 13 at a predetermined interval, but at least one auxiliary projection 13 may be provided as necessary. In that case, providing at least one auxiliary protrusion 13A may improve the air retention during the marker molding.

  As shown in FIG. 12, the auxiliary protrusion 13 </ b> A has a height H <b> 5 from the sidewall portion surface 2 a of the one end 13 </ b> A <b> 1 connected to the marker 8 that is 0.2 to 0.8 times the height H <b> 1 of the marker 8. As described above, the one end portion 13A1 is preferably raised. Further, as shown in FIG. 12, the auxiliary protrusion 13A has a height H6 from the sidewall surface 2a of the other end 13A2 connected to the circumferential protrusion 9, which is 0 of the height H2 of the circumferential protrusions 9A and 9B. It is preferable that the other end 13A2 is raised so as to be 2 to 1.0 times. As a result, the air remaining on the label 8 and the inner surface of the mold during tire vulcanization can be more efficiently released to the mold groove for molding the circumferential projection 9 through the mold groove for molding the auxiliary projection 13A. Further, the vulcanization failure caused by the air pocket at the time of molding the sign 8 can be further improved.

  Even if the height H5 of the one end 13A1 of the auxiliary projection 13A is lower than 0.2 times the height H1 of the marker 8, the height H6 of the other end 13A2 of the auxiliary projection 13A is the height H2 of the circumferential projection 9. Even if it is lower than 0.2 times, the effect of escaping the remaining air is small. When the height H5 of the one end portion 13A1 of the auxiliary protrusion 13A is higher than 0.8 times the height H1 of the marker 8, the visibility of the marker 8 decreases. Even if the height H6 of the other end 13A2 of the auxiliary protrusion 13A is higher than 1.0 times the height H2 of the circumferential protrusion 9, the effect of releasing the remaining air does not change, so the other end of the auxiliary protrusion 13A. The upper limit of the height H6 of 13A2 is 1.0 times the height H2 of the circumferential protrusion 9.

  In the present invention, as described above, when a plurality of markers 8 are provided on the recessed surface 11 formed in the region defined by the circumferential projections 9A and 9B and the radial projection 10, the surface of the sidewall portion 2 of the marker 8 is provided. It is the periphery of the sign 8 that the total volume of the portion 8 s protruding from 2 a is in the range of 0.7 to 1.3 times the volume of the space portion 14 from the surface 2 a of the sidewall portion 2 to the recessed surface 11. It is good for improving the rubber flow failure and further reducing the vulcanization failure due to air accumulation. When there is the auxiliary protrusion 13, the space portion 14 is a space portion from the surface 2 a of the sidewall portion 2 to the recessed surface 11 including the auxiliary protrusion 13.

  In the present invention, the height H1 of the marker 8 is preferably in the range of 0.2 mm to 1.5 mm. If the height H1 of the sign 8 is lower than 0.2 mm, the visibility of the sign 8 is lowered. When the height H1 of the sign 8 exceeds 1.5 mm, it becomes difficult to improve the vulcanization failure due to the air trap during the sign molding.

  The heights H2 and H3 of the circumferential protrusion 9 and the radial protrusion 10 are preferably in the range of 0.2 mm to 2.0 mm. If the heights H2 and H3 of the circumferential projection 9 and the radial projection 10 are lower than 0.2 mm, the groove depth of the mold for molding the circumferential projection 9 and the radial projection 10 becomes too shallow. The effect of escaping to the outside is greatly reduced. If the heights H2 and H3 of the circumferential protrusions 9 and the radial protrusions 10 exceed 2.0 mm, it is not preferable because the rubber flowing into the grooves of the mold for forming the protrusions 9 and 10 is likely to be defective.

  The widths W2 and W3 of the circumferential protrusion 9 and the radial protrusion 10 are preferably in the range of 0.2 mm to 5.0 mm. If the widths W2 and W3 of the circumferential protrusion 9 and the radial protrusion 10 are narrower than 0.2 mm, the effect of releasing the remaining air to the outside is greatly reduced. If the widths W2 and W3 of the circumferential protrusion 9 and the radial protrusion 10 exceed 5.0 mm, it is not preferable because the rubber flowing into the groove of the mold for molding the protrusions 9 and 10 tends to be poor.

  The depth D of the recessed surface 11 is preferably in the range of 0.2 mm to 1.0 mm. When the depth D of the recessed surface 11 is shallower than 0.2 mm, the visibility of the sign is lowered, and it becomes difficult to effectively improve the vulcanization failure due to the air pocket during the sign molding. Even when the depth D of the recessed surface 11 exceeds 1.0 mm, it is difficult to effectively improve the vulcanization failure due to the air pocket during the sign molding. More preferably, the depth D of the recessed surface 11 is in the range of 0.4 mm to 0.8 mm.

  Note that the tire maximum width position P1 described above is that a tire is mounted on a standard rim prescribed by JATMA (Japan Automobile Tire Association), and an air pressure of 5% of the air pressure corresponding to the maximum load capacity prescribed by JATMA is applied. It is in a no-load state. The same applies to the tire cross-section height SH. The tire maximum width position P1 is a position where the tire width is maximum on the surface 2a of the sidewall portion 2. In the case where a decoration such as a mark 8 is provided on the surface 2a of the sidewall portion 2, this is a position where the width of the tire is maximized on the surface 2a of the sidewall portion 2 in a state where the decoration is not provided. If it is difficult to determine the position at which the tire width is maximum on the surface 2a of the sidewall portion 2 in the absence of decoration, the surface 2a of the sidewall portion 2 corresponding to the position at which the width of the carcass layer is maximized. The position is the tire maximum width position P1.

  Although this invention can be used conveniently for the pneumatic tire especially for heavy loads, it is not limited to it.

  The tire size is 11R22.5, the tire structure is the same in FIG. 1 and the sign is the same in FIG. 2, the mark height H1, the circumferential protrusion height H2, the radial protrusion height H3, the indentation depth D, The tires 1 and 2 of the present invention (Examples 1 and 2) in which the height Hn of the portion surrounded by the annular protrusion of the sign as shown in Table 1 were prepared. Further, in the tire 2 of the present invention, an auxiliary projection was provided as shown in FIG. 10, and a tire 3 of the present invention (Example 3) having a height H4 as shown in Table 1 was produced. Also, conventional tires 1 and 2 (conventional examples 1 and 2) having the same structure as the tire 1 of the present invention except that there are no circumferential protrusions and radial protrusions and a sign is directly provided on the surface of the sidewall portion are produced. did.

  In the tires 1 to 3 of the present invention, the total sum of the volume of the portion protruding from the surface of the sidewall portion of the sign with respect to the volume of the space portion from the surface of the sidewall portion to the recessed surface is as shown in Table 1. Table 1 also shows the height H1 of the signs of the conventional tires 1 and 2 and the height Hn of the portion surrounded by the annular protrusions of the signs.

  The prepared tire was mounted on a standard rim prescribed by JATMA, filled with air pressure (700 kPa) corresponding to the maximum load capacity, and a sensory evaluation test of the visibility of the sign by 50 panelists was performed. The evaluation result is indicated by an index value where the conventional tire 1 is 100. The larger this value, the better the visibility.

  Further, when the state of occurrence of vulcanization failure due to the air pocket of the mark was examined in the produced tire, the results shown in Table 1 were obtained. The occurrence of vulcanization failure is shown in three stages A1, A2 and A3. A1 means that no vulcanization failure occurs, A2 means that the vulcanization failure rate is less than 1%, and A3 means that the vulcanization failure rate is 1% or more.

  From Table 1, it can be seen that the tire of the present invention can improve the visibility of the sign and can reduce the occurrence of the vulcanization failure of the sign due to the air trap.

It is a half sectional view showing one embodiment of the pneumatic tire of the present invention. It is the elements on larger scale which show the label | marker formed in the tire of FIG. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. FIG. 4 is a cross-sectional view taken along arrow IV-IV in FIG. 2. It is sectional explanatory drawing which shows the flow of the unvulcanized rubber of the label | marker part at the time of tire vulcanization. FIG. 6 is a cross-sectional explanatory view showing the flow of unvulcanized rubber following FIG. 5. FIG. 7 is a cross-sectional explanatory view showing the flow of unvulcanized rubber and the flow of remaining air following FIG. 6. FIG. 5 is a cross-sectional view taken along arrow VIII-VIII in FIG. 2. It is sectional explanatory drawing which shows the flow of the unvulcanized rubber which forms the label | marker of FIG. In other embodiment of the pneumatic tire of this invention, it is the elements on larger scale which show the label | marker formed in the surface of the sidewall part. It is XX arrow sectional drawing of FIG. It is sectional drawing which shows the preferable example of an auxiliary | assistant protrusion.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tread part 2 Side wall part 2a Surface 3 Bead part 8 Label | marker 8m Protrusion part 8n Part 9, 9A, 9B Circumferential protrusion 10 Radial protrusion 11 Recessed surface 13, 13A Auxiliary protrusion 13A1 One end part 13A2 The other end part 14 Space part

Claims (6)

  Two circumferential protrusions extending in the tire circumferential direction are arranged on the surface of the sidewall portion at a predetermined interval in the tire radial direction, and connected to the two circumferential protrusions between the two circumferential protrusions. And at least two radial projections extending in the tire radial direction are arranged at a predetermined interval in the tire circumferential direction, and a region defined by the circumferential projection and the radial projection is recessed from the surface of the sidewall portion. At least one mark formed on the hollow surface and protruding from the surface of the sidewall portion is provided on the hollow surface, and the height of the mark from the surface of the sidewall portion is set to the circumferential protrusion from the surface of the sidewall portion. A pneumatic tire having a height equal to or less than the height of the radial protrusion from the surface of the sidewall portion.   The marker has a marker having an annular protrusion and a portion surrounded by the annular protrusion, and the surrounded portion is higher than the surface of the sidewall portion and the height of the enclosed portion from the surface of the sidewall portion. The pneumatic tire according to claim 1, wherein the length is 0.25 times or less of the height of the sign.   At least one auxiliary protrusion is provided on the recessed surface so as to be connected to the circumferential protrusion and the marker, and the ratio H4 / D of the height H4 of the auxiliary protrusion from the recessed surface to the depth D of the recessed surface is 0.6 ≦ The pneumatic tire according to claim 1 or 2, satisfying a relationship represented by H4 / D≤1.0.   One end of the auxiliary projection connected to the sign is made higher than the surface of the sidewall portion, and the height from the surface of the sidewall portion of one end of the auxiliary projection is 0.2 to 0.8 of the height of the sign. The pneumatic tire according to claim 3, which is doubled.   The other end of the auxiliary projection connected to the circumferential projection is made higher than the surface of the sidewall portion, and the height of the other end portion of the auxiliary projection from the surface of the sidewall portion is 0 of the height of the circumferential projection. The pneumatic tire according to claim 3 or 4, wherein the pneumatic tire is 2 to 1.0 times.   A plurality of the signs protruding from the surface of the sidewall portion on the depression surface, and the total volume of the portions protruding from the sidewall portion surface of the plurality of signs is partitioned by the circumferential protrusion and the radial protrusion. The pneumatic tire according to any one of claims 1 to 5, wherein the pneumatic tire has a volume that is 0.7 to 1.3 times the volume of a space portion from the surface of the sidewall portion to the recessed surface in the region.

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