JP2009029249A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make dry steering stability, braking performance and snow performance compatible in a high level. <P>SOLUTION: A plurality of lug grooves 19 (25, 33) extending in a tire width direction W are formed at intervals in a tire peripheral direction C in land part rows 11 (13, 15). One end part of each lug grooves 19 (25, 33) is opened at peripheral direction main grooves 7 (5) or a tread end E. Each of the other end part of each of the lug grooves 19 (25, 33) is terminated in each of the land part rows 11 (13, 15). Each of bridge sipes 21 (27, 35) is formed at one side edge part of a bottom surface of each of the lug grooves 19 (25, 33). Each of the bridge sipes 21 (27, 35) is extended in an extension direction of the lug grooves 19 (25, 33) beyond the other end part of each of the lug grooves 19 (25, 33). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  Pneumatic tires such as pneumatic radial tires that can achieve both high levels of dry steering stability and braking performance (brake performance on dry and wet road surfaces) and snow performance (mainly traction performance on snowy road surfaces). Regarding tires.

  Among the performances of pneumatic tires, dry steering stability / brake performance and snow performance are in a trade-off relationship, and various developments have been made to achieve both dry steering stability / brake performance and snow performance. Patent Document 1 discloses a pneumatic tire that can improve snow performance while maintaining dry steering stability performance and braking performance.

  That is, the tread of the pneumatic tire according to the prior art is formed with a plurality of circumferential main grooves extending in the tire circumferential direction, and extends in the tire circumferential direction by the plurality of circumferential main grooves and a pair of tread ends. A plurality of land sections are partitioned. Each land row is formed with a plurality of lug grooves extending in the tire width direction at intervals in the tire circumferential direction, and both end portions (one end portion and the other end portion) of each lug groove are circumferential. In other words, each lug groove is divided into a land portion row. A sipe is formed at the center of the bottom of each lug groove. Each land portion row is partitioned into a plurality of blocks by a plurality of lug grooves.

Therefore, according to the pneumatic tire according to the prior art, because the sipe is formed in the central portion of the groove bottom of the lug groove, without opening the lug groove deeper, to facilitate the opening of the lug groove at the start of contact, Snow on the road surface can be taken into the lug groove. Thereby, the so-called snow column effect by compressing the snow in the lug groove during the ground contact can be sufficiently exhibited while suppressing the decrease in the rigidity of the block, in other words, the decrease in the rigidity of the land row. Therefore, in the pneumatic tire according to the prior art, the reduction of the contact area during driving on the dry road surface is suppressed, and the traction in the front-rear direction on the road surface on the snow is improved while maintaining the dry steering stability performance and the brake performance. Performance can be improved.
JP 2001-187517 A

  By the way, in the pneumatic tire according to the prior art, each lug groove is designed to divide each land portion row, and sipes are respectively formed in the central portion of the groove bottom of each lug groove, When a large load is applied to the tire ground contact surface when traveling on a dry road surface, the groove width of the lug groove is widened, and the rigidity of the land portion row is lowered. Therefore, it is difficult to secure a sufficient contact area when traveling on a dry road surface, and it becomes difficult to improve dry steering stability performance and braking performance. That is, in the pneumatic tire according to the prior art, there is a problem that it is difficult to achieve both a dry steering stability performance / brake performance and a snow performance at a high level.

  Then, an object of this invention is to provide the pneumatic tire of a novel structure which can solve the above-mentioned problem.

  A first feature of the present invention (feature of the invention described in claim 1) is that a plurality of circumferential main grooves extending in the tire circumferential direction are formed in the tread, and the plurality of circumferential main grooves and a pair of tread ends. In a pneumatic tire in which a plurality of land portion rows extending in the tire circumferential direction are partitioned by at least one of the land portion rows, a plurality of lug grooves extending in the tire width direction are formed at intervals in the tire circumferential direction. One end of each lug groove is opened to the circumferential main groove or the tread end, respectively, and the other end of each lug groove is terminated in any of the land portion rows, and the bottom of each lug groove is The gist is that a bridge sipe is formed on one side edge portion, and each bridge sipe extends beyond the other end of the lug groove in the extending direction of the lug groove.

  According to the first feature, since the bridge sipes are formed at the bottoms of the respective lug grooves, it is possible to facilitate the opening of the lug grooves at the start of contact without deepening the lug grooves, and the road surface on snow. Can be fully taken into the lug groove. Thereby, the so-called snow column effect by compressing the snow in the lug groove during the ground contact can be sufficiently exhibited while suppressing a decrease in the rigidity of any of the land portion rows.

  In addition, the other end of each lug groove is terminated in any one of the land portion rows, in other words, any one of the land portion rows maintains a so-called rib-connected state, and each bridge sipe is formed. Is one side edge portion of the bottom surface of the lug groove, and each bridge sipe extends in the extending direction of the lug groove beyond the other end of the lug groove. Even when added to the ground plane, the wall surfaces of the bridge sipe, in other words, the partition portions partitioned by the bridge sipe support each other, thereby suppressing the opening of the groove width of the lug groove, It is possible to sufficiently ensure the rigidity of the land portion row.

  The second feature of the present invention (feature of the invention described in claim 2) is summarized in that each lug groove is inclined with respect to the tire circumferential direction in addition to the first feature.

  According to a third feature of the present invention (a feature of the invention described in claim 3), in addition to the first feature or the second feature, any of the land portion rows is a land portion located in a tire central region. The gist is that it is a line.

  According to the present invention, even when a large load is applied to the tire ground contact surface when traveling on a dry road surface, it is possible to suppress the opening of the groove width of the lug groove and sufficiently ensure the rigidity of any of the land portion rows. As well as being able to fully demonstrate the snow column effect, it ensures sufficient ground contact area when driving on dry roads, improves dry steering stability performance and braking performance, and provides forward and backward traction on snowy road surfaces This can increase snow performance. In other words, according to the present invention, dry steering stability performance / brake performance and snow performance can be achieved at a high level.

  An embodiment will be described with reference to FIGS. 1 and 2. Here, FIG. 1 is a developed plan view showing a part of the tread of the pneumatic tire according to the embodiment, and FIG. 2 is a perspective view showing a main part of the embodiment.

  As shown in FIGS. 1 and 2, a first circumferential main groove 5 extending in the tire circumferential direction C is formed in the tire central region of the tread 3 of the pneumatic tire 1 according to the embodiment. Second circumferential main grooves 7 and 9 extending in the tire circumferential direction C are formed on both sides of the first circumferential main groove 5 in FIG. A center land portion row 11 (13) extending in the tire circumferential direction C is partitioned by the adjacent first circumferential main groove 5 and second circumferential main groove 7 (9), and the second circumferential main groove 7 (9) and the tread end E define a shoulder land portion row 15 (17) extending in the tire circumferential direction C.

  In one center land portion row 11, lug grooves 19 extending in the tire width direction W are formed at intervals in the tire circumferential direction C, and each lug groove 19 is inclined with respect to the tire circumferential direction C, respectively. is doing. One end of each lug groove 19 is opened in one second circumferential main groove 7, and the other end of each lug groove 19 is terminated in one center land portion row 11. ing. A bridge sipe 21 is formed on one side edge portion of the bottom surface of each lug groove 19, and each bridge sipe 21 extends in the extending direction of the lug groove 19 beyond the other end of the lug groove 19. And the front-end | tip part of each bridge sipe 21 is each opened by the 1st circumferential direction main groove 5. As shown in FIG. One center land portion row 11 is formed with narrow grooves 23 extending in the tire circumferential direction C so as to communicate with the plurality of lug grooves 19.

  On the other center land portion row 13, lug grooves 25 extending in the tire width direction W are formed at intervals in the tire circumferential direction C, and each lug groove 25 is inclined with respect to the tire circumferential direction C, respectively. is doing. One end of each lug groove 25 is opened in the first circumferential main groove 5, and the other end of each lug groove 25 is terminated in the other center land portion row 13. . A bridge sipe 27 is formed on one side edge portion of the bottom surface of each lug groove 25, and each bridge sipe 27 extends beyond the other end of the lug groove 25 in the extending direction of the lug groove 25. Thus, the tip of each bridge sipe 27 is opened in the other second circumferential main groove 9. Further, in the other center land portion row 13, sub lug grooves 29 extending in the tire width direction W are formed at intervals in the tire circumferential direction C, and one end portion of each sub lug groove 29 is connected to the other center land portion 13. Each of the sub-lag grooves 29 is terminated in the partial row 13, and the other end of each sub-lag groove 29 is opened in the other second circumferential main groove 9. In the other center land portion row 13, narrow grooves 31 extending in the tire circumferential direction C are formed so as to communicate with the plurality of lug grooves 25 and the plurality of sub lug grooves 29.

  On one shoulder land portion row 15, lug grooves 33 extending in the tire width direction W are formed at intervals in the tire circumferential direction C. One end of each lug groove 33 is opened to the tread end E, and the other end of each lug groove 33 is terminated in one shoulder land portion row 15. A bridge sipe 35 is formed on one side edge portion of the bottom surface of each lug groove 33, and each bridge sipe 35 extends in the extending direction of the lug groove 33 beyond the other end of the lug groove 33. Thus, the tip of each bridge sipe 35 is opened in one second circumferential main groove 7. Further, in one shoulder land portion row 15, sub lug grooves 37 extending in the tire width direction W are formed at intervals in the tire circumferential direction C, and one end portion of each sub lug groove 37 is formed on one shoulder land portion 15. Each of the sub-lag grooves 37 is terminated in one of the sub-rows 15, and the other end of each sub-lag groove 37 is opened in one second circumferential main groove 7. One shoulder land portion row 15 is formed with narrow grooves 39 extending in the tire circumferential direction C so as to communicate with the plurality of lug grooves 33 and the plurality of sub lug grooves 37.

  In the other shoulder land portion row 17, lug grooves 41 extending in the tire width direction W are formed at intervals in the tire circumferential direction C. One end of each lug groove 41 is terminated in the other shoulder land portion row 17, and the other end of each lug groove 41 is opened to the tread end E. Further, in the other shoulder land portion row 17, sub lug grooves 43 extending in the tire width direction W are formed at intervals in the tire circumferential direction C, and one end portion of each sub lug groove 43 is the other second lug. Opened in the circumferential main groove 9, the other end of each sub-lag groove 43 is terminated in the other shoulder land portion row 17. In the other shoulder land portion row 17, narrow grooves 45 extending in the tire circumferential direction C are formed so as to communicate with the plurality of lug grooves 41 and the plurality of sub lug grooves 43.

  Then, the effect | action and effect of embodiment are demonstrated.

  Since the bridge sipes 21 (27, 35) are respectively formed on the groove bottoms of the lug grooves 19 (25, 33), the lug grooves 19 (25, 33) are not deepened without the lug grooves 19 (25, 33) being deepened. The opening can be promoted, and the snow on the snow surface can be sufficiently taken into the lug grooves 19 (25, 33). As a result, the snow in the lug grooves 19 (25, 33) is compressed during the ground contact while suppressing a decrease in rigidity of the land portion row 11 (13, 15) in which the bridge sipes 21 (27, 35) are formed. Thus, the so-called snow column effect can be sufficiently exhibited.

  Further, the other end of each lug groove 19 (25, 33) is terminated in the land portion row 11 (13, 15), in other words, the land portion row 11 (13, 15) is in a so-called rib-connected state. The bridge sipe 21 (27, 35) is formed on one side edge portion of the bottom surface of the lug groove 19 (25, 33), and each bridge sipe 21 (27, 35) is connected to the lug groove 19 ( 25, 33) extend in the extending direction of the lug grooves 19 (25, 33) beyond the other end portions of the lag grooves 19 (25, 33). Therefore, even when a large load is applied to the tire ground contact surface when traveling on a dry road surface, the bridge sipe 21 (27 , 35), in other words, the partition portions partitioned by the bridge sipes 21 (27, 35) support each other, thereby suppressing the opening of the groove width of the lug grooves 19 (25, 33), Land Part 11 (13,1 The rigidity of) can be sufficiently secured. In particular, the bridge sipe 21 (27) is formed in the center land portion row 11 (13) that is always grounded regardless of the magnitude of the load applied to the pneumatic tire 1 and the magnitude of the input. Can fully demonstrate.

  Furthermore, since each lug groove 19 (25) formed in the center land portion row 11 (13) is inclined with respect to the tire circumferential direction C, the lug groove 19 can be applied even if a lateral force acts on the tire contact surface. The opening of the groove width of (25) can be suppressed, and the rigidity of the center land portion row 11 (13) can be sufficiently secured.

  Therefore, according to the embodiment, even when a large load is applied to the tire ground contact surface when traveling on a dry road surface, the opening of the groove width of the lug groove 19 (25, 33) is suppressed, and the land portion row 11 (13, 15). As well as being able to sufficiently secure the rigidity of the snow column, it is possible to fully demonstrate the snow column effect, so that sufficient contact area when driving on the dry road surface is secured, improving dry steering stability performance and braking performance, In addition, the traction in the front-rear direction on the road surface on the snow can be increased to improve the snow performance. In other words, according to the embodiment, the dry steering stability performance / brake performance and the snow performance can be achieved at a high level.

  Further, even if a lateral force is applied to the tire ground contact surface, the opening of the groove width of the lug groove 19 (25) can be suppressed and the rigidity of the center land portion row 11 (13) can be sufficiently secured. The stability performance can be further improved.

(Modification)
A modification of the embodiment will be described with reference to FIG. Here, FIG. 3 is a developed plan view showing a part of the tread of the pneumatic tire according to the modification of the embodiment.

  As shown in FIG. 3, the pneumatic tire 47 according to the modification of the embodiment has the air according to the embodiment except that the bridge sipe 21 (27) formed in the center land portion row 11 (13) is omitted. The configuration is substantially the same as the configuration of the entering tire 1. In addition, about the component corresponding to the component in the pneumatic tire 1 which concerns on embodiment among the some components in the pneumatic tire 47 which concerns on the modification of embodiment, it attaches | subjects the same number in a figure, and demonstrates it. Is omitted.

  Also in the modified example of the embodiment, the same operations and effects as those of the above-described embodiment are obtained.

  In addition, this invention is not restricted to description of the above-mentioned embodiment, In addition, it can implement in a various aspect. Further, the scope of rights encompassed by the present invention is not limited to these embodiments.

(Comparative example)
First, before describing the specific content of an Example, the pneumatic tire which concerns on a comparative example is demonstrated easily with reference to FIG. Here, FIG. 4 is a plan view showing a part of the tread of the pneumatic tire according to the comparative example.

  As shown in FIG. 4, the pneumatic tire 49 according to the comparative example includes a bridge sipe 21 (27) formed in the center land portion row 11 (13) and a bridge sipe 35 formed in one shoulder land portion row 15. The configuration is substantially the same as the configuration of the pneumatic tire 1 according to the embodiment except that is omitted. In addition, about the component corresponding to the component in the pneumatic tire 1 which concerns on embodiment among the some components in the pneumatic tire 49 which concerns on a modification, the same number is attached | subjected in a figure and description is abbreviate | omitted. .

(Specific contents of the example)
(i) Dry steering stability performance, riding comfort on dry road surface, and snow performance The pneumatic tire 1 according to the embodiment is the invention product 1, the pneumatic tire 47 according to the modification of the embodiment is the invention product 2, The pneumatic tire 49 according to the comparative example was manufactured as a comparative product with a tire size of 225 / 65R17. Next, inventive product 1, inventive product 2, and comparative product are assembled to a rim (17X61 / 2JJ), filled with air of a predetermined internal pressure (210 KPa), and mounted on a vehicle (Honda CR-V). did. And by driving the vehicle equipped with the invention 1, the vehicle equipped with the invention 2, and the vehicle equipped with the comparative product on the dry road surface and the snowy road surface, the dry maneuvering stability performance, the riding comfort on the dry road surface, In addition, an actual vehicle test was conducted on snow performance (traction performance on a snowy road surface). As a result of the test, the dry steering stability performance, the riding comfort on the dry road surface, and the feeling evaluation of the snow performance (average of a plurality of drivers) are summarized by index display as shown in Table 1 below. In addition, it shows that the dry steering stability performance, the ride comfort in the dry road surface, and the snow performance are better as the index of feeling evaluation of the dry maneuverability stability, the ride comfort in the dry road surface, and the snow performance is larger. Yes.

  That is, as shown in Table 1, it was confirmed that the inventive product 1 and the inventive product 2 maintain the high dry maneuvering stability performance and the high riding comfort in the dry road surface like the comparative product. Inventive product 1 and inventive product 2 were confirmed to have superior snow performance as compared with the comparative product.

(ii) Dry brake performance and wet brake performance Driving a vehicle equipped with Invention 1, a vehicle equipped with Invention 2 and a vehicle equipped with a comparison product on a dry road test course and a wet road test course, Brake tests were conducted on dry brake performance and wet brake performance by measuring the braking distance from 100 km / h to stopping. The test results are summarized as shown in Table 2 below.

  That is, as shown in Table 2, it was confirmed that the inventive product 1 and the inventive product 2 have high dry brake performance and high wet brake performance as in the comparative product.

It is a plane development view showing a part of tread of a pneumatic tire concerning an embodiment. It is a perspective view which shows the principal part of embodiment. It is a plane development view showing a part of the tread of the pneumatic tire concerning the modification of an embodiment. It is a plane development view showing a part of tread of a pneumatic tire concerning a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pneumatic tire 3 ... Tread 5 ... 1st circumferential direction main groove 7 ... 2nd circumferential direction main groove 9 ... 2nd circumferential direction main groove 11 ... Center land part row | line | column 13: Center land part row | line | column 15 ... Shoulder land part row | line | column 17 ... Shoulder land row 19 ... Lug groove 21 ... Bridge sipe 25 ... Lug groove 27 ... Bridge sipe 33 ... Lug groove 35 ... Bridge sipe

Claims (3)

In a pneumatic tire in which a plurality of circumferential main grooves extending in the tire circumferential direction are formed in the tread, and a plurality of land portion rows extending in the tire circumferential direction are partitioned by the plurality of circumferential main grooves and a pair of tread ends. ,
A plurality of lug grooves extending in the tire width direction are formed in at least one of the land portion rows at intervals in the tire circumferential direction, and one end portion of each lug groove is opened in the circumferential main groove or the tread end, respectively. The other end of each lug groove is terminated in one of the land portion rows, a bridge sipe is formed on one side edge portion of the bottom surface of each lug groove, and each bridge sipe is connected to the other of the lug grooves. A pneumatic tire characterized by extending in the extending direction of the lug groove beyond the end portion.   The pneumatic tire according to claim 1, wherein each lug groove is inclined with respect to the tire circumferential direction.   The pneumatic tire according to claim 1 or 2, wherein any one of the land portion rows is a land portion row located in a tire central region.

Images