JP6148942B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire provided with a rib pattern in a tread portion.

  Various types of pattern configurations have been proposed for pneumatic tires (hereinafter referred to as “tires”) having rib patterns in the tread portion. For example, the pattern configuration described in Patent Document 1.

  As shown in FIG. 1 of Patent Document 1, this pattern configuration is a narrow groove extending in the tire circumferential direction in one of the ribs located on the vehicle outer side than the tire equator (reference numeral in FIG. 1 of the document). “12”) and a plurality of inclined grooves (“16a”) extending from the narrow groove to the tire equator side and arranged at intervals in the tire circumferential direction.

  By the way, the tire is deformed by friction with the road surface when the vehicle is in contact with the vehicle, and the shape of the tire is restored when the tire is separated from the road surface. By repeating this deformation and shape restoration, the structure (rubber or the like) constituting the tire generates heat. If this heat continues to be stored in the tissue, the tissue will eventually soften and will not be able to withstand external forces and tire pressure, which may result in tire breakdown (blowout).

  According to the description of Patent Document 1, in the invention according to the document, drainage and circumferential rigidity are imparted to the ribs formed with the grooves by forming the narrow grooves and the inclined grooves. However, no particular measures have been taken against the heat generation.

  In order to prevent heat from being stored in the tire structure, it is conceivable to form a groove having a large width on the tread surface or to increase the formation density of the groove. However, if the width of the groove is large, the space between the ribs is increased by that amount, and the rib itself is also reduced (thinned). If it does so, when it receives external force, since a rib becomes easy to bend, we are anxious about the rigidity of a tire falling. Similarly, when the formation density of the grooves is increased, the individual ribs are reduced (thinned) by the grooves having a small formation interval, and there is a concern that the rigidity of the tire may be reduced.

JP 2012-131423 A

  Then, this invention makes it a subject to provide the pneumatic tire excellent in heat dissipation, maintaining rigidity.

The present invention is the pneumatic tire having a rib pattern in the tread portion, the tread portion includes an outer main grooves extending in the tire circumferential direction, outside of the vehicle than the tire equator to the vehicle when mounting the tire, said outer main An outer narrow groove extending parallel to the groove and positioned outside the outer main groove, and an inner narrow groove positioned inside the outer main groove, the outer main groove and the outer narrow groove; An outer thin rib extending in the tire circumferential direction is positioned between the outer main groove and the inner thin groove, an inner thin rib extending in the tire circumferential direction is positioned between the outer thin groove, wherein positioned outer thick rib on the opposite side in the tire width direction to the outer narrow rib, the inner narrow groove, located inner thick rib on the opposite side in the tire width direction to the inner narrow ribs, the outer corners switching in the outer narrow groove side in the tire width direction of the thick rib In all the possible, adjacent to share edges to the outside of the outer narrow groove, is arranged a plurality of outer notch so as to be aligned in the tire circumferential direction, the inner tire width direction of the inner thick ribs The corners on the narrow groove side are notched, so that the inner narrow grooves are adjacent to each other so as to share an edge, and a plurality of inner notches are arranged so as to be aligned in the tire circumferential direction,
Each of the outer notch and the inner notch has a shape in which one end is wide in the tire circumferential direction and the other end is narrow in the tire circumferential direction.

  According to this configuration, each notch has a shape in which one end is wide in the tire circumferential direction and the other end is narrow in the tire circumferential direction. For this reason, since the thin rib which tries to deform | transform by receiving external force can be received by the edge of the said narrow part, rigidity can be ensured in the said part. In addition to this, since heat is radiated from the inner surface of the notch portion, the heat radiating area can be increased compared to the case where the notch portion is not formed, and the heat radiating area can be increased by the wide portion. It is possible to effectively prevent the heat from being continuously stored.

Further, each of the outer cutout part and the inner cutout part has a slope connecting the edge on the side away from the narrow groove in the tire width direction in the cutout part and the edge on the side close to the narrow groove. And the inclined surface has an end edge on a side away from the narrow groove at a position outside the diameter than an end edge near the narrow groove. According to this configuration, it is possible to reduce the cutout at the corner on the narrow groove side of the thick rib as compared with the case where each cutout is formed as a recess having a constant depth. For this reason, the fall of the rigidity especially in the said thick rib can be suppressed. For this reason, the balance between rigidity and heat dissipation is good.

Further, the plurality of outer cutout portions and the plurality of inner cutout portions may be positioned on the vehicle outer side than the tire equator when the tire is mounted on the vehicle. According to this configuration, when the tire is mounted on the vehicle, heat dissipation can be imparted while maintaining rigidity, particularly in the outer region of the tread surface where the external force from the road surface is the greatest during cornering.

The thick rib includes a plurality of sipes arranged at intervals in the tire circumferential direction, and the groove connected to each of the outer notch and the inner notch in the thick rib is only the sipes. And can. According to this structure, compared with the case where the groove | channel with a groove width larger than a sipe is connected to each said notch part, since the space which the connected groove | channel has is small, the deformation | transformation allowance of a rib can be made small. Therefore, it is possible to suppress a decrease in rigidity due to the groove connected to each notch and an increase in the amount of heat generated due to the deformation of the rib.

Further, the sipe is connected to each of the outer cutout portion and the inner cutout portion at an end portion in the tire circumferential direction of an edge on the side away from the narrow groove, and the sipe is connected to the sipe. Can be made to extend in a direction parallel to the tire width direction with respect to the edge or in an oblique direction on one end side in the tire circumferential direction and in the tire circumferential direction. According to this configuration, when the thin rib receives an external force, the thin rib to be deformed can be supported by the connecting portion, and as a result, the rigidity of the tire can be maintained.

In the connecting portion, the end edge and the sipe may intersect at an obtuse angle at an angle that opens to the side away from the narrow groove with respect to the end edge . According to this configuration, the thin ribs to be deformed can be supported by the obtuse corners, and as a result, the tire rigidity can be further maintained.

The thick rib includes a plurality of sipes arranged at intervals in the tire circumferential direction, and each of the outer notch and the inner notch has a formation interval of 2 in the tire circumferential direction of the plurality of sipes. It can be formed over a length corresponding to twice or more. According to this structure, the heat radiation area in one notch part can be enlarged, and it can contribute to the improvement of heat dissipation.

Further, the sipe is connected to each of the outer cutout portion and the inner cutout portion at an end portion in the tire circumferential direction of an end edge on a side away from the narrow groove, and the end edge at the connection portion. And the sipe may be in an acute relationship with respect to an angle opened to a side away from the narrow groove with respect to the end edge . According to this configuration, two surfaces are formed corresponding to the acute angle portion. Since these two surfaces are resistant to deformation of the thick rib, the rigidity of the tire can be maintained.

The present invention are that rigidity is ensured by receiving the outer cutout portion and the thin rib at the edge of the narrow portion in each of the inner notch (outer thin rib, inner narrow ribs), the outer By releasing heat from the inner surface of each of the cutout portion and the inner cutout portion (particularly wide portion), it is possible to provide a pneumatic tire excellent in heat dissipation while maintaining rigidity.

It is the figure seen from the radial direction which shows the tread pattern of the pneumatic tire which concerns on one Embodiment (Example 1) of this invention. It is a principal part enlarged view of FIG. BRIEF DESCRIPTION OF THE DRAWINGS (A)-(C) is the outline of the perspective which cut | disconnected one part by radial cross section which shows the outer side notch part or inner side notch part of the pneumatic tire which concerns on each embodiment (Examples 1-3) of this invention. FIG. (D)-(F) is the schematic of the perspective which cut | disconnected one part by radial direction cross section which shows Comparative Examples 1-3. (G) is a table | surface which shows the result which the inventor of this application evaluated the heat dissipation and rigidity about the form of said (A)-(F). It is an enlarged end view at the time of cut | disconnecting an outer notch periphery periphery in a radial direction, Comprising: (A) shows a narrow part and (B) shows a wide part. (A)-(D) is the schematic which shows each recessed part shape at the time of seeing from the radial direction based on other embodiment of an outer side notch part or an inner side notch part. It is the figure seen from the radial direction which shows the tread pattern of the pneumatic tire which concerns on the comparative example 4 used for evaluation. It is the figure seen from the radial direction which shows the tread pattern of the pneumatic tire which concerns on the comparative example 5 used for evaluation. It is the figure seen from the radial direction which shows the tread pattern of the pneumatic tire which concerns on Example 4 used for evaluation. It is the figure seen from the radial direction which shows the tread pattern of the pneumatic tire which concerns on Example 5 used for evaluation.

  Next, the present invention will be described by taking up a pneumatic tire according to an embodiment. In the expression of the direction described below, for “inside and outside”, when the tire is mounted on the vehicle, the side closer to the center in the width direction of the vehicle is the inside, and the far side is the outside. Moreover, let the upper side on FIG.1, FIG.2, FIG.6-9 be the tire circumferential direction one side (or one end side), and let the lower side be the tire circumferential direction other side (or other end side).

  FIG. 1 is a view showing a tread pattern of a tire according to the present embodiment, and FIG. 2 is an enlarged view of a main part of FIG. The tread pattern of this tire is asymmetric in the tire width direction with reference to the tire equator E shown in FIG. As shown in FIG. 1, the right side in the figure is the outside when the vehicle is mounted, and the left side in the figure is the inside.

In this tire, three main grooves 1 (11 to 13) extending in the tire circumferential direction are formed, and the tread portion T is divided by the three main grooves 11 to 13, whereby four tire circumferential directions are formed. Ribs 2 (21 to 24) which are land portions extending in the direction are formed. The three main grooves 1 are formed as thicker grooves than the other grooves formed in the tire. The ribs 2 of the present embodiment are a center inner rib 21, a center outer rib 22, an outermost rib 23, and an innermost rib 24.

  Out of the three main grooves 11 to 13 formed, the outer main groove 13 is located on the outer side of the tire equator E, and the outer main groove 13 is located on the outermost side. A narrow groove 31 and an inner narrow groove 32 are formed. And among the outermost ribs 23 located outside the outer main groove 13, the outer thick ribs 23b located in the outer region are provided with a plurality of sipes 4 ... 4 arranged at intervals in the tire circumferential direction. Each sipe 4 extends from the outer edge of the outermost rib 23 inward and in an oblique direction on the other side in the tire circumferential direction, and inclines toward the other side in the tire circumferential direction inward from the bent portion 41. Connected to the outer narrow groove 31 and the outer notch 51. Further, among the central outer ribs 22 positioned inward of the outer main groove 13, the inner thick ribs 22b positioned in the inner region are also provided with a plurality of sipes 6 ... 6 disposed at intervals in the tire circumferential direction. Prepare. Each sipe 6 extends from the inner edge of the central outer rib 22 outward and in an oblique direction on one side in the tire circumferential direction, and is connected to the inner narrow groove 32 and the inner notch 52.

  The outer narrow groove 31 is a groove that extends continuously in the tire circumferential direction and has a smaller groove width than the outer main groove 13, and is a sipe in this embodiment. The outermost ribs 31 divide the outermost ribs 23 inward and outward by the outer narrow grooves 31, the outer thin ribs 23 a are formed in the inner region of the outermost ribs 23, and the outer thick ribs 23 b are formed in the outermost regions. As shown in FIGS. 1 and 2, the outer thin rib 23a is a rib having the same width as that of the outer main groove 13 in the tire width direction.

  The inner narrow groove 32 is also a groove that extends continuously in the tire circumferential direction, like the outer thin groove 31, and has a smaller groove width than the outer main groove 13, and is a sipe in this embodiment. The inner thin rib 32 divides the central outer rib 22 in the inner and outer directions, the inner thin rib 22a is formed in the outer region of the central outer rib 22, and the inner thick rib 22b is formed in the inner region. The inner thin rib 22a has substantially the same width as the outer thin rib 23a.

  In the center inner rib 21 and the innermost rib 24 as well, the ribs 21 and 24 are divided inward and outward by sipes 211 and 241 extending continuously in the tire circumferential direction. Ribs 21a and 24a are formed, and thick ribs 21b and 24b are formed in the inner region.

  In this manner, the inner thin rib 22a and the outer thin rib 23a are formed symmetrically inside and outside with the outer main groove 13 interposed therebetween.

  Next, a plurality of outer sides are arranged so as to be adjacent to the outer narrow groove 31 so as to share the end edges 311 and 511 and to be aligned in the tire circumferential direction by cutting out the corners inside the outer thick rib 23b. Cutout portions 51... 51 are arranged. The phrase “adjacent so as to share the edge” is, in other words, adjoining so that the space of the outer narrow groove 31 is expanded in the tire width direction. Similarly, a plurality of inner notches are arranged adjacent to each other so as to share the edges 321 and 521 on the inner side of the inner narrow groove 32 by being cut out at the corners on the outer side of the inner thick rib 22b. Parts 52... 52 are arranged. First, the outer notch 51 will be described.

  The outer notch 51 is wide at the lower end side (one end in the tire circumferential direction at the outer notch 51) shown in FIG. 2 and the other upper end in the tire circumferential direction at the outer notch 51 (see FIG. 2). ) Is narrow. That is, the outer notch 51 has three end edges (inner edges) that are straight when viewed from the radially outward direction (assuming that the tire circumferential direction and tire width direction curves on the surface of the tread portion T are ignored). A recess recessed in the radially inward direction, defined by an edge 511, an outer edge 512, and a circumferential edge 513). Of the three edges, the inner edge 511 coincides with the outer edge 311 that is the outer corner of the outer narrow groove 31 when viewed from the radial direction (that is, the outer notch 51 is It shares an edge with the outer narrow groove 31). And this inner side edge 511 has a tire circumferential direction one end part high (it exists in a diameter outer side), and a tire circumferential direction other end part is low (it exists in a diameter inner side), as shown to FIG. 3 (A). For convenience of illustration, the shape of the outer cutout 51 shown in FIG. 3A is a mirror image of the shape shown in FIG. Thus, the inner edge 511 is a linear edge that becomes lower from one end in the tire circumferential direction toward the other end. In addition, the inner edge 511 of the present embodiment is at a position that is one step higher (outside the diameter) than the bottom surface of the outer narrow groove 31 as shown in FIG.

  The outer end edge 512 coincides with the inner end edge 511 at one end in the tire circumferential direction at the outer notch 51, and away from the inner end edge 511 toward the other end side (the distance increases). Extended). The outer edge 512 is different from the inner edge 511, and as shown in FIG. 3A, one end in the tire circumferential direction and the other end in the tire circumferential direction at the outer notch 51 are positioned at the same height. , Located along the surface of the outermost rib 23.

The circumferential edge 513 extends by connecting the other end in the tire circumferential direction of the inner edge 511 and the other end in the tire circumferential direction of the outer edge 512. The above three end edges 511 to 513 form an outer notch 51 which is a recess opened in a triangle when viewed from the radially outward direction.

  As described above, the inner end edge 511 is lowered from the one end portion in the tire circumferential direction at the outer notch 51 toward the other end side in the tire circumferential direction (in the radial inner direction), and the outer end edge 512 is In the outer notch 51, one end in the tire circumferential direction and the other end in the tire circumferential direction are located at the same height. Therefore, the outer edge 512 is at a higher position than the inner edge 511. For this reason, as shown in FIG. 3A, a main heat radiating surface 514 that is a flat inclined surface from the outer edge 512 toward the inner edge 511 is formed. Due to the height relationship of the end edges 511, 512, the main heat radiating surface 514 is high on the outer end edge 512 side (externally on the diameter side) and low on the inner end edge 511 side (externally on the diameter side). And the main heat radiating surface 514 has a tire circumferential direction one end part high, and a tire circumferential direction other end part is low. For this reason, the main heat radiating surface 514 is an inclined surface heading obliquely downward to the left in FIG.

  The main heat radiating surface 514 formed in this way radiates heat to the outside air around the tire. Incidentally, heat is also radiated from the inner inner surface of the outer narrow groove 31 and a slope 232 (described later) adjacent to the outer notch 51 (that is, these surfaces function as auxiliary heat radiating surfaces). In the outer notch 51, since the heat radiation area can be secured by the main heat radiation surface 514 or the like, the heat generated in the tire structure during traveling of the vehicle can be appropriately dissipated around the tire. Therefore, by being able to balance heat storage and heat dissipation, it is possible to prevent the heat from being stored in the tire structure and causing the tire to be destroyed (blowout).

  In addition to ensuring the heat radiation area in this way, the outer cutout 51 has an effect of maintaining the rigidity of the outermost rib 23. That is, for example, as shown in FIGS. 3E and 3F, the outer fine ribs 23a receive an external force due to grounding or cornering as compared with a configuration in which a groove having a constant width is provided in the tire circumferential direction. When trying to deform so as to bend outward, the inner edge 511 of the outer notch 51 is shown by a broken line in FIG. 4A, particularly in the narrow portion near one end in the tire circumferential direction at the outer notch 51. By contacting the outer thin rib 23a deformed outward as shown in FIG. 8, further outward deformation (falling down) of the outer thin rib 23a can be suppressed. Since the outer thin rib 23a is supported by the narrow portion in this way, a decrease in rigidity of the outermost rib 23 is suppressed. As a result, it is possible to suppress a decrease in steering stability particularly on a dry road surface.

  Further, since the outer notch 51 of the present embodiment has a slope (main heat radiating surface 514) between the outer edge 512 and the inner edge 511, the outer notch 51 is assumed to be a recess having a constant depth. Compared to the case, since the space of the outer notch 51 corresponding to the recess becomes smaller, it is possible to suppress a decrease in rigidity. For this reason, the outer notch 51 of this embodiment has a good balance between rigidity and heat dissipation.

  Next, the inner notch 52 has a 180-degree point symmetry with respect to the outer notch 51 in the radial direction. When viewed from the radially outward direction, the outer edge 512 of the outer notch 51 and the inner edge 522 of the inner notch 52 are parallel. From such a configuration, it is possible to give a sense of unity in design to those who see the tire (tread portion).

  The inner edge 511, the outer edge 512, the circumferential edge 513, and the main heat radiating surface 514 of the outer notch 51 are respectively an outer edge 521, an inner edge 522, a circumferential edge 523 of the inner notch 52, It corresponds to the main heat radiating surface 524, and the function of each part also corresponds in the same way.

  The plurality of outer notches 51... 51 configured as described above are arranged such that the wide side portion and the narrow side portion are adjacent to each other via the sipe 4. Similarly, the plurality of inner notches 52... 52 are arranged such that the wide side portion and the narrow side portion are adjacent to each other via the sipe 6. That is, the sipes 4 and 6 are connected to the notches 51 and 52, respectively.

  Regarding the connection, the grooves connected to the notches 51 and 52 in the thick ribs 23b and 22b are only the sipes 4 and 6, and the other grooves are not connected. Here, assuming that a groove having a groove width larger than that of the sipe is connected, each thick rib is formed when the space portion of the groove receives an external force in the portion sandwiching the groove in each thick rib 23b, 22b. Since it can be a deformation allowance of 23b, 22b, it becomes a cause of increasing the amount of heat generated by the deformation. On the other hand, when a sipe is connected as in this embodiment, the space can be made relatively small and the amount of deformation can be suppressed, so that the amount of heat generation can be suppressed.

  The edges 512 and 522 on the side away from the outer main groove 13 at the notches 51 and 52 are sipe 4 at one end 512a in the outer notch 51 and at the other end 522a in the inner notch 52, respectively. 6 and obtuse angle. By crossing at an obtuse angle in this way, obtuse angle portions 233 and 223 are formed by the end edges 512 and 522 and the sipes 4 and 6 in the thick ribs 23b and 22b adjacent to the end portions 512a and 522a. For this reason, the thick ribs 23b, 22b are not obstructed by the structure (rubber or the like) by a relatively large distance in the inside and outside directions at the obtuse angle portions 233, 223. If this part has an acute angle, the distance between the edges 512 and 522 of the notches 51 and 52 and the sipes 4 and 6 is small in the inner and outer directions, so that the structure (rubber etc.) is relative to the sipes 4 and 6. Breaks at a small distance. From this, the obtuse angle can exhibit the effect of suppressing the deformation (falling down) of each of the thin ribs 23a and 22a described above. Therefore, the rigidity of the outermost rib 23 and the central outer rib 22 can be maintained. The connection between the notches 51 and 52 and the sipes 4 and 6 is not limited to the crossing at the obtuse angle, and the sipes 4 and 6 are connected to the notches 51 and 52 at the connecting portions of the sipes 4 and 6. 6 is a direction parallel to the tire width direction (horizontal direction shown in the figure) or an oblique direction toward the one end side in the tire circumferential direction (upward direction shown in the figure) with respect to the edges 512 and 522. You can

  As described above, each of the cutout portions 51 and 52 mainly exhibits heat dissipation in the wide side portion, and mainly secures rigidity in the narrow side portion. Thus, each notch part 51 and 52 can show | play simultaneously the effect | action which changes with parts.

  Further, the circumferential edge 513 of the outer notch 51 is seen from the radially outward direction by the rib edge 231 that extends inward from the bent portion 41 in the sipe 4 and in the diagonal direction on the other side in the tire circumferential direction, and the sipe 4. In this case, a slope 232 that is a triangle is formed. Therefore, the slope 232 is adjacent to one side in the tire circumferential direction of the sipe 4 inward of the bent portion 41. In addition, it can be said that this slope 232 is also a part of the sipe 4 (a part in which the space of the sipe 4 is expanded). The outer edge 512 intersects the rib edge 231 at an acute angle at the other end 512b. The inclined surface 232 is adjacent to the main heat radiating surface 514, and a circumferential edge 513 is located between the two surfaces 232 and 514.

Similarly, in the inner notch 52, the circumferential edge 52 3, forming a rib edge 221 which extends parallel to the sipe 6, the inclined surface 222 is trapezoidal when viewed from the radially outward direction by the sipe 6 To do. Therefore, the slope 222 is adjacent to the other side of the sipe 6 in the tire circumferential direction. The outer edge 522 and the rib edge 221 intersect at an acute angle. The slope 222 is adjacent to the main heat radiating surface 524, and a circumferential edge 523 is located between the two surfaces 222 and 524.

  That is, the connections of the sipes 4 and 6 to the notches 51 and 52 are made at the end portions 512b and 522b of the end edges 512 and 522 on the side away from the narrow grooves 31 and 32, respectively. The edges 512 and 522 and the sipes 4 and 6 may have an acute angle relationship. According to this configuration, the two surfaces 232, 514/222, and 524 are formed corresponding to the portion having the acute angle relationship.

  The narrow rib 21a in the central inner rib 21 is formed with a triangular notch groove 212 having an apex located on the inner side when viewed from the radial direction at an extended position of the inclined surface 222. The notch groove 212 gives the design uniformity to the inclined surface 222 and expands the space of the center main groove 12 in the tire width direction at the position of the notch groove 212, whereby the center main groove 12. By suppressing the air column resonance phenomenon, the effect of suppressing running noise is exhibited.

  As described above, the circumferential edges 513 and 523 are located between the two surfaces. For this reason, the above two surfaces against the operation in which the outer thick rib 23b of the outermost rib 23 or the inner thick rib 22b of the center outer rib 22 tends to deform mainly in the tire circumferential direction due to the external force received by the tire during vehicle travel. And the sharp corners formed by the circumferential edges 513 and 523 are stretched, so that deformation of the ribs 23 and 22 can be suppressed. That is, since the two surfaces are resistant to deformation of the thick ribs 23b and 22b, the rigidity of the tire can be maintained. Therefore, the rigidity of the ribs 22 and 23 can be maintained particularly at the acute angle portion 234 including the other end portion 512b of the outermost rib 23 and the acute angle portion 224 including the one end portion 522b of the central outer rib 22. it can. Therefore, since the contact pressure can be made uniform in the tire circumferential direction, the occurrence of vibration and pattern noise during vehicle travel can be suppressed.

  Moreover, each notch part 51 and 52 is located over the length equivalent to 2 times or more of the formation space | interval in the tire peripheral direction of the sipe 4 and 6. FIG. For this reason, a large heat radiation area can be secured in each of the cutout portions 51 and 52.

  In addition, about the sipe 4 and 6 which has the positional relationship which cross | intersects in the circumferential direction approximate center of each main heat radiating surface 514,524, as shown in FIG. 2, each main heat radiating surface 514,524 is not penetrated. Therefore, the main heat radiating surfaces 514 and 524 are not divided by the sipes 4 and 6 at substantially the center in the circumferential direction, and become one elongated triangle. For this reason, it is possible to give a sense of unity in design to a person who sees the notches 51 and 52.

  As shown in FIG. 1, the notches 51 and 52 formed as described above are located on the vehicle outer side than the tire equator E when the tire is mounted on the vehicle. Here, when the tire is mounted on the vehicle, the rib positioned on the outside of the vehicle has a larger contact amount than the ribs on the other portions of the tire, and the deformation amount increases. is there. For this reason, by positioning the notches 51 and 52 on the vehicle outer side than the tire equator E, it is possible to impart heat dissipation to the outer region of the tread surface while maintaining rigidity.

  The form of the outer notch 51 and the inner notch 52 is not limited to this embodiment. For example, the main heat radiating surfaces 514 and 524 are not limited to the plane of the present embodiment, but are illustrated more than the plane (imaginary) connecting the end edges 511 and 521 and the end edges 512 and 522 as shown in FIG. It can also be a curved surface such as a convex surface bulging obliquely upward (in addition to a convex surface, it may be a concave surface or a surface having both irregularities (a wavy surface) or the like). Thus, by making the main heat radiating surfaces 514 and 524 curved surfaces, the heat radiating area can be made larger than in the case of a flat surface. However, from the viewpoint of maintaining rigidity, it is better to make the space of each of the cutout portions 51 and 52 smaller, so that the convex surface is preferable to the concave surface.

  Further, as shown in FIG. 3 (C), the main heat radiating surfaces 514 and 524 are in the radial direction from the outer edges 512 and 522, and from the bottom of the vertical surfaces 514a and 524a in the tire circumferential direction. It can also consist of extending horizontal surfaces 514b, 524b. In the form shown in FIG. 3C, the notches 51 and 52 and the narrow grooves 31 and 32 are continuous without boundaries, so that the inner edge 511 and the outer edge 521 appear clearly. Absent.

  Here, when the narrow groove X1 as shown in FIG. 3D is continuously formed along the tire circumferential direction (Comparative Example 1), the wide groove X2 as shown in FIG. When formed continuously along the circumferential direction (Comparative Example 2), when a groove X3 whose bottom surface is inclined to one side in the tire width direction as shown in FIG. 3F is formed along the tire circumferential direction. (Comparative Example 3) And Example 1 shown in FIG. 3 (A), Example 2 shown in FIG. 3 (B), Example 3 shown in FIG. Relative evaluation was performed from the viewpoint of rigidity.

  Evaluation of heat resistance was performed through evaluation of durability. Durability is the speed symbol H (210km / The test was performed in accordance with the conditions for tires in h). The durability was evaluated by starting at a speed of 100 km / h and incrementing the speed by 10 km / h every 10 minutes until the tire broke down with a drum tester. Therefore, the greater the speed at the time of tire failure, the better the durability. The tire used for evaluation has a size of 215 / 55R17, a rim of 17 × 7 sJ, and an air pressure of 230 kPa. In addition, by performing the above test, while the tire is rotating, the deflection is repeated and internal heat is generated, and the separation that causes delamination of the tread rubber, the belt layer, and the carcass in which the carcass cord rapidly fatigues and bursts. It reaches. Therefore, a tire with a high durability evaluation can be said to be a tire with high heat dissipation (not easily stored).

  Regarding the evaluation of rigidity, as before, the size is 215 / 55R17, the rim is 17 x 7 s J, and the pneumatic pressure is 230 kPa. The tire is mounted on a domestic 2500 cc sedan, running on the slalom dry road, and the test driver. The sensory evaluation was performed.

  Each evaluation is shown in FIG. The evaluation results are “◎”, “◯”, “Δ”, and “×” in order of good evaluation. As a result, in the shapes of Examples 1 to 3, although the rigidity evaluation in Example 3 was slightly poor, it was confirmed that the heat dissipation and the rigidity were balanced.

  Next, the inventor of the present application applied the tread shown in FIG. 6 (Comparative Example 4), FIG. 7 (Comparative Example 5), FIG. 8 (Example 4), FIG. 9 (Example 5), and FIG. Since the evaluation was made by making a tire with a pattern, this evaluation will be described. In addition, about FIGS. 6-9, the code | symbol is attached | subjected only to the part required for description fundamentally.

  6 differs from the above-described embodiment (Example 1) in that it corresponds to the sipe 4 in that the portions corresponding to the notches 51 and 52 are not formed and the outermost rib 23. As a result, a groove 4 ′ having a groove width larger than that of the sipe is formed. Further, since the portion corresponding to the inner notch 52 is not formed, the inclined surface 222 ′ formed every other sipe 6 in the central outer rib 22 is different in shape from the inclined surface 222 of the above embodiment. Yes.

  Further, the comparative example 5 shown in FIG. 7 differs from the above-described embodiment (Example 1) in that a groove 4 ′ having a groove width larger than that of the sipe is formed in the outermost rib 23 corresponding to the sipe 4. Is a point. The inclined surfaces 222 ′ formed on every other sipe 6 in the central outer rib 22 have the same shape as the comparative example 4 shown in FIG. 6. An outer notch 51 is formed in the inner region of the outermost rib 23, and an inner notch 52 is formed in the outer region of the center outer rib 22. Each notch 51, 52 is located over the length of one formation interval in the tire circumferential direction of the sipes 4, 6. Each of the notches 51 and 52 is wide at the lower end in the figure and narrow at the upper end in the figure. That is, the outer notch 51 and the inner notch 52 are substantially symmetrical inside and outside with the outer main groove 13 in between. Further, the notches 51 and 52 are different in shape from the notches 51 and 52 of the embodiment (Example 1), and the outer notch 51 is formed on the lower end side of the embodiment (Example). It is adjacent to the groove 4 ′ without a surface corresponding to the inclined surface 232 of 1). The inner notch 52 is adjacent to the sipe 6 on the lower end side in the figure.

  The embodiment (Example 4) shown in FIG. 8 has substantially the same configuration as the comparative example 5 shown in FIG. 7, but the same sipe 4 as that of the above-described embodiment (Example 1) is formed instead of the groove 4 ′. In addition, the same slope 232 as that of the above embodiment (Example 1) is formed every other sipe 4.

  Further, the embodiment (Example 5) shown in FIG. 9 has substantially the same configuration as that of Example 4 shown in FIG. 8, but the wide portion and the narrow portion of the inner notch 52 are upside down in the drawing, The shape of the slope 222 is the same as that of the above-described embodiment (Example 1).

  The evaluation of durability is the same as that described above, and the evaluation of turning performance is the same as the evaluation of rigidity described above.

Table 1 shows a summary of each evaluation. The higher the number, the higher the rating.

Moreover, using the tire which formed each notch part 51,52 and the part corresponded to this in the shape shown to the said FIG.3 (A)-(F) among the tread parts shown in FIG. Table 2 shows the evaluation results. The higher the number, the higher the rating.

  Thus, it was confirmed that the tire according to the present invention has an advantage when viewed comprehensively.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the summary of this invention.

  For example, although three main grooves 1 are formed in the above-described embodiment, only one main groove 1 can be formed, or two or more than four can be formed.

  Further, the outer narrow groove 31 and the inner narrow groove 32 of the present embodiment are formed as grooves having substantially the same width as the sipes 4 and 6, but the rigidity of the central outer rib 22 and the outermost rib 23 is the same as the groove width. The ribs can be set as appropriate on the condition that the ribs are not lowered until the heat generation during vehicle running becomes significant.

  Moreover, although the tire of the said embodiment was provided with the outer notch part 51 ... 51 and the inner notch part 52 ... 52, it is provided with only one of the outer notch part 51 ... 51 and the inner notch part 52 ... 52. It can also be.

  In the tire according to the embodiment, the wide side portion and the narrow side portion are arranged adjacent to each other through the sipes 4 and 6 for the plurality of notches 51... 51, 52. However, the present invention is not limited to this, and the plurality of notches 51... 51, 52... 52 may be arranged so that the ribs (land portions) 22 and 23 are located therebetween.

  Further, the end edges 512 and 522 corresponding to the hypotenuses of the triangles in the notches 51 and 52 are not limited to one straight line as in the embodiment. For example, as shown in FIG. 5 (A), it is bent so as to extend in a different direction in the middle, as shown in FIG. 5 (B), bent outward in the figure, as shown in FIG. 5 (C). It can be in various forms, such as an inwardly curved one or a stepped one as shown in FIG. In short, the shape of each of the notches 51 and 52 is not particularly limited as long as one end is wide in the tire circumferential direction and the other end is narrow. it can. Furthermore, although not illustrated, the shape is not limited to the shape in which the end portions in the tire circumferential direction converge to one point like the triangle in the embodiment, and may have a shape having a width (trapezoidal shape).

  Lastly, the configuration of the above-described embodiment (Example 1) and the effects produced by the configuration will be summarized.

  In this embodiment, in the pneumatic tire having a rib pattern on the tread portion T, the tread portion T has at least one main groove 13 extending in the tire circumferential direction, and at least extends in parallel to the main groove 13. The narrow grooves 31 and 32 are provided, and between the main groove 13 and the narrow grooves 31 and 32, narrow ribs 23a and 22a extending in the tire circumferential direction are positioned, and the narrow grooves 31 and 32 are provided. The thick ribs 23b and 22b are located on the opposite side of the thin ribs 23a and 22a in the tire width direction, and the corners on the thin groove side of the thick ribs 23b and 22b are cut away, thereby A plurality of notches 51 and 52 are arranged adjacent to the grooves 31 and 32 and arranged in the tire circumferential direction. Each of the notches 51 and 52 has a tire width at one end in the tire circumferential direction at each notch. Wide in direction, also That one end is the same narrow shape.

  According to this configuration, each of the notches 51 and 52 has a shape in which one end is wide in the tire circumferential direction and the other end is narrow in the tire circumferential direction. For this reason, since the thin ribs 23a and 22a to be deformed by receiving an external force can be received by the end edges 512 and 522 of the narrow portion, rigidity can be ensured in the portion. In addition, since heat is radiated from the inner surfaces of the notches 51 and 52, the heat radiation area can be increased as compared with the case where the notches 51 and 52 are not formed, and the heat radiation area can be further increased by the wide portion. Further, it is possible to effectively suppress the heat from being continuously stored in the tissue constituting the tire.

  Further, the notches 51 and 52 are respectively provided with end edges 512 and 522 on the side away from the narrow grooves 31 and 32 in the tire width direction of the notches 51 and 52, and the sides close to the narrow grooves 31 and 32. The main heat dissipating surface 514 is connected to the end edges 511 and 521, and the main heat dissipating surface 514 has the end edges 512 and 522 away from the narrow grooves 31 and 32, and the narrow grooves 31 and 32. It is possible to be at a position outside the diameter relative to the edges 511 and 521 on the side closer to. According to this configuration, the cutouts at the corners on the narrow groove side of the thick ribs 23b and 22b can be made smaller than when the cutout portions 51 and 52 are formed as concave portions having a constant depth. For this reason, especially the fall of the rigidity in the said thick ribs 23b and 22b can be suppressed. For this reason, the balance between rigidity and heat dissipation is good.

  Further, the plurality of cutout portions 51 and 52 can be positioned on the vehicle outer side than the tire equator E when the tire is mounted on the vehicle. According to this configuration, when the tire is mounted on the vehicle, heat dissipation can be imparted while maintaining rigidity, particularly in the outer region of the tread surface T where the external force from the road surface is the greatest during cornering.

  The thick ribs 23b and 22b include a plurality of sipes 4 and 6 arranged at intervals in the tire circumferential direction, and grooves connected to the notches 51 and 52 at the thick ribs 23b and 22b. Can be only the sipes 4 and 6. According to this structure, since the space which the connected groove | channel has is small compared with the case where the groove | channel whose groove width is larger than the sipes 4 and 6 is connected to each said notch part 51 and 52, the deformation | transformation allowance of a rib is reduced. Can be small. Therefore, it is possible to suppress a decrease in rigidity due to the grooves connected to the notches 51 and 52 and an increase in heat generation accompanying the deformation of the ribs.

  The sipe 4, 6 is connected to the notches 51, 52 at the ends 512a, 522a in the tire circumferential direction of the end edges 512, 522 on the side away from the narrow grooves 31, 32, In this connection portion, the sipes 4 and 6 are in a direction parallel to the tire width direction with respect to the end edges 512 and 522, or in the tire width direction (and) in an oblique direction on one end side in the tire circumferential direction. It can be made to extend. According to this configuration, when the thin ribs 23a and 22a receive an external force, the thin ribs 23a and 22a to be deformed can be supported by the connecting portion, and as a result, the tire rigidity can be maintained.

  Further, at the connecting portion, the end edges 512 and 522 and the sipes 4 and 6 may intersect at an obtuse angle. According to this configuration, the thin ribs 23a and 22a to be deformed can be supported by the obtuse corners, and as a result, the tire rigidity can be further maintained.

  The thick ribs 23b and 22b include a plurality of sipes 4 and 6 arranged at intervals in the tire circumferential direction, and the notches 51 and 52 are arranged in the tire circumferential direction of the plurality of sipes 4 and 6, respectively. It can be formed over a length corresponding to twice or more of the formation interval. According to this structure, the heat radiation area in one notch part 51 and 52 can be enlarged, and it can contribute to the improvement of heat dissipation.

  The sipe 4, 6 is connected to the notches 51, 52 at the end in the tire circumferential direction of the edge on the side away from the narrow grooves 31, 32. The edge and the sipes 4 and 6 may have an acute angle relationship. According to this configuration, two surfaces are formed corresponding to the acute angle portion. Since these two surfaces become resistance to the deformation of the thick ribs 23b and 22b, the rigidity of the tire can be maintained.

1 main groove 13 outer main groove 2 rib 21 center inner rib 22 center outer rib 22a inner thin rib 22b inner thick rib 23 outermost rib 23a outer thin rib 23b outer thick rib 24 innermost rib 31 narrow groove, outer narrow groove 32 narrow Groove, inner narrow groove 4 Sipe (outermost rib)
51 Notch, Outer Notch 512 Edge, Outer Edge (Outer Notch)
514 Slope, main heat dissipation surface (outside notch)
52 Notch, Inner Notch 522 Edge, Inner Edge (Inner Notch)
524 Slope, main heat dissipation surface (inside notch)
6 Sipe (center outer rib)
T tread part E tire equator

Claims (8)

In pneumatic tires with rib patterns on the tread,
The tread portion extends in the tire circumferential direction, extends in parallel to the outer main groove, and is located outside the outer main groove, and extends in parallel with the outer main groove, which is positioned on the vehicle outer side than the tire equator when the tire is mounted on the vehicle. An outer narrow groove, and an inner narrow groove located inside the outer main groove ,
Between the outer narrow grooves and the outer main groove is positioned outer thin rib extending in the tire circumferential direction,
Between the outer main groove and the inner narrow groove, an inner thin rib extending in the tire circumferential direction is located,
The outer narrow grooves located outer thick rib on the opposite side in the tire width direction and the outer narrow ribs,
The inner thin rib has an inner thick rib located on the opposite side of the inner thin rib in the tire width direction,
Said that corners are cut in the tire width direction of the outer diameter the ribs the outer narrow groove side adjacent to share edges to the outside of the outer narrow groove, a plurality so as to be aligned in the tire circumferential direction The outer notch of the
A plurality of the inner thick ribs adjacent to each other so as to share an end edge and aligned in the tire circumferential direction by notching a corner on the inner narrow groove side in the tire width direction of the inner thick rib. The inner notch of the
Each of the outer cutout part and the inner cutout part has a shape in which one end is wide in the tire width direction and the other end is the same narrow in the tire circumferential direction at each cutout. A featured pneumatic tire. Each of the outer cutout portion and the inner cutout portion has a slope connecting an end edge on the side of the cutout portion away from the narrow groove in the tire width direction and an end edge on the side close to the narrow groove. ,
2. The pneumatic tire according to claim 1, wherein an edge of the inclined surface on the side farther from the narrow groove is located at a radially outer position than an edge of the side closer to the narrow groove. The pneumatic tire according to claim 1 or 2, wherein the plurality of outer cutout portions and the plurality of inner cutout portions are positioned on the vehicle outer side than the tire equator when the tire is mounted on the vehicle. The thick rib includes a plurality of sipes arranged at intervals in the tire circumferential direction,
The pneumatic tire according to any one of claims 1 to 3, wherein a groove connected to each of the outer notch and the inner notch is only the sipe in the thick rib. The sipe is connected to each of the outer cutout portion and the inner cutout portion at an end portion in the tire circumferential direction of an edge on a side away from the narrow groove, and the sipe is 5. The pneumatic tire according to claim 4, wherein the pneumatic tire extends in a direction parallel to the tire width direction with respect to the edge, or in an oblique direction on one end side in the tire circumferential direction and in the tire width direction. . 6. The pneumatic tire according to claim 5, wherein at the connection portion, the end edge and the sipe intersect at an obtuse angle at an angle that opens to a side away from the narrow groove with respect to the end edge . The thick rib includes a plurality of sipes arranged at intervals in the tire circumferential direction,
Each of the said outer side notch part and the said inner side notch part is formed over the length equivalent to 2 times or more of the formation space | interval in the tire circumferential direction of these sipe. Pneumatic tire described in 2. The sipe is connected to each of the outer cutout portion and the inner cutout portion at an end portion in the tire circumferential direction of an edge on the side away from the narrow groove. 5. The pneumatic tire according to claim 4, wherein the sipe is in an acute angle relationship at an angle that opens to a side away from the narrow groove with respect to the end edge .

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