JP5035961B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire with improved handling stability (handling property) in any traveling on a snow road (snow road surface), a frozen road surface (ice road surface), and a normal paved road (dry road surface). is there. The pneumatic tire of the present invention is a pneumatic tire particularly suitable as a negative camber vehicle, particularly as a minivan tire.

  A pneumatic tire having a block pattern formed by a main rib groove and a sub rib groove is known (for example, Patent Documents 1 and 2). The pneumatic tire disclosed in Patent Document 1 is intended to improve snow handling stability, and forms a block formed by rib grooves and lug grooves, and has a pattern negative rate on the outer side and inner side of the tire. In FIG. 1, two thick straight rib grooves on the outer side of the mounting and two narrow straight rib grooves on the inner side of the mounting are shown in FIG. The tire which has is illustrated.

  The pneumatic tire disclosed in Patent Document 2 specifies the sipe structure for the purpose of improving snow and snow road performance, wet braking performance, uneven wear resistance, and the like. The tire has thick straight rib grooves at the inner central portion and the outer outer central portion, and undulating or zigzag thin rib grooves at the equator portion, mediate portion and shoulder portion. .

JP 2006-192929 A JP 2002-316517 A

  However, in recent years, negative camber vehicles, mainly minivans, have increased, and when the tires of Patent Documents 1 and 2 are attached to such negative camber vehicles, handling performance in cornering on a road surface with a high friction coefficient such as a general dry road surface is achieved. On the other hand, it was found that the cornering on the ice road did not improve much.

  An object of the present invention is to provide a pneumatic tire having improved handling performance on any of an ice road surface, a snow road surface, and a dry road surface in view of the problems of the above-described known technology.

The pneumatic tire according to the present invention includes an equatorial main rib groove formed in the equator, an inner main rib groove formed on the inner side of the equatorial main rib groove, and an outer side of the equator main rib groove. The center part of the mediate part which has three main rib grooves which consist of the formed outer main rib groove and is formed between the inner main rib groove and the equatorial part main rib groove on the inner side from the equator part and possess a width of the narrow sub-rib groove than said main rib grooves in the central portion of the shoulder portion of the side side of the inner main rib grooves, not having or the said auxiliary rib grooves in the apparatus outside than the equatorial portion main rib grooves The secondary rib groove outside the apparatus from the equator main rib groove is smaller than the auxiliary rib groove inside the apparatus from the equator main rib groove .

  According to the tread pattern of the above configuration, a pneumatic tire with improved handling performance can be obtained on any of an ice road surface, a snow road surface, and a dry road surface even when the negative camber is mounted on a vehicle.

  Preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a plan view showing a part of a tire tread portion flattened. The tread pattern 10 of the pneumatic tire of the present invention includes a main rib groove 12a formed in the equator, a main rib groove 12b formed inside the main rib groove 12a in the equator, and a main rib groove in the equator. This is a block pattern having main rib grooves 12c formed on the outer side of 12a and lug grooves 22a and 22b.

  The main rib groove 12b and the equatorial main rib groove 12a are formed on the inner side of the equator, and the secondary rib groove 14a is narrower than the main rib groove 12b at the center of the mediate portion M on the equator side of the main rib groove 12b. However, a secondary rib groove 14b having a width smaller than that of the main rib groove 12b is formed in the central portion of the shoulder portion S on the side of the main rib groove 12b. By the main rib groove, the sub rib groove, and the lug groove, the block 18 is formed on the inner side from the equator and the block 16 is formed on the outer side from the equator. A plurality of sipes 20 are formed in each of the blocks 16 and 18.

  The reason why the tire having the tread pattern with the above configuration improves the handling performance on any of the ice road surface, the snow road surface, and the dry road surface when mounted on a negative camber vehicle is not clear, but is due to the following action It is considered a thing. A tire mounted on a negative camber vehicle has a higher load on the inner side during acceleration / braking on a road surface with a high friction coefficient such as a dry road surface, but a higher load on the outer side when turning. On the other hand, since the ice / snow road surface has a low friction coefficient, the load on the inner side of the mounting is increased during acceleration / braking, but the increase in the load on the outer side of the mounting is small during turning. According to the present invention illustrated in FIG. 1, since there are fewer auxiliary rib grooves on the outer side than the inner side of the mounting, the rigidity of the block is improved, the handling property on the dry road surface is improved, and the mediate portion and the shoulder on the inner side of the mounting are improved. It is presumed that since the auxiliary rib groove is formed in the part, acceleration / braking on the ice / snow road surface and handling at the time of turning are improved.

  In the above tread pattern, instead of the main rib groove 12a in the equator portion, a narrow block formed by two sub rib grooves may be formed in the equator portion.

  In the tread pattern of FIG. 1, an example in which there is no secondary rib groove on the outside of the equator from the equator is shown. In addition, the handleability is further improved by an action that is considered to increase the rigidity of the shoulder block.

  The width of the main rib grooves 12a, 12b, 12c is preferably 5 to 12 mm. If the groove width of the main rib groove is too narrow, drainage and snow drainage performance will deteriorate, and if it is too wide, the ground contact area of the block will become small, which is not preferable. The main rib grooves 12a, 12b, and 12c may have the same width or different widths. The width of the auxiliary rib grooves 14a and 14b is preferably 0.8 to 4.5 mm. If the groove width of the secondary rib groove is too narrow, the snow performance deteriorates due to a decrease in snow removal performance.If the groove width is too wide, the rigidity of the block decreases and the block is liable to deform at the time of ground contact. Decreases in ice performance.

  In the tread pattern illustrated in FIG. 1, the main rib grooves 12a, 12b, and 12c and the auxiliary rib grooves 14a and 14b are all straight, but at least one of them may be zigzag. The lug groove is also straight in FIG. 1, but it may be zigzag or wavy.

  In the tread pattern 10 illustrated in FIG. 1, blocks 16 and 18 are formed by lug grooves 22 a and 22 b intersecting the main rib grooves 12 a, 12 b and 12 c and the sub rib grooves 14 a and 14 b. The sipe 20 is formed, but at least a part of the sipe is preferably a three-dimensional sipe. Such a three-dimensional sipe can increase the rigidity of the block and further improve the handling performance.

  The three-dimensional sipe is a sipe having a groove width of 0.2 to 0.7 mm and has a wave shape (or zigzag shape). The sipe is formed in the traveling direction of the wave, and the uneven rubber portion of the wave is engaged. In addition to having the irregularities in the wave height direction and engaging the rubber part forming the irregularities, the block has the effect of increasing the collapse resistance of the block. Three-dimensional sipes are known in Japanese Patent No. 3516647, Japanese Patent Application Laid-Open No. 2006-298331, etc., and these known three-dimensional sipes can be used in the present invention.

  The pneumatic tire of the present invention has the effects as described above, and particularly when it is mounted on a negative camber vehicle, the handling performance is excellent on any of the ice road surface, the snow road surface, and the dry road surface. Useful as a snow tire.

  Examples and the like specifically showing the configuration and effects of the present invention will be described below. In addition, each performance evaluation of the tire was performed as follows.

(1) Dry road surface handling performance A tire is mounted on a real vehicle (domestic 3000cc class FF sedan), and under the load conditions of one passenger, straight driving, turning, braking, etc. are performed on the dry road surface, and the driver's sensory test The handling was evaluated by Evaluation is shown by an index when Comparative Example 1 is set to 100, and the larger the value, the better the dry performance.

(2) Ice road surface handling performance The tire is mounted on the same vehicle as the dry road surface handling performance described above, and straight driving, turning, braking, etc. are performed on the frozen road surface under the load conditions of one person riding, and the driver's sensory test The handling was evaluated by Evaluation is shown by an index when Comparative Example 1 is set to 100, and the larger the value, the better the dry performance.

(3) Snow road surface handling performance The tire is mounted on the same vehicle as the dry road surface handling performance described above, and running straight, turning, braking, etc. on a snowy road surface under the load conditions of one passenger ride, Handling was evaluated. Evaluation is shown by an index when Comparative Example 1 is set to 100, and the larger the value, the better the dry performance.

Example 1
Each performance evaluation described above was performed using a tire having a tread pattern as shown in FIG. The used tire has a size of 205 / 65R15, the main rib grooves 12a, 12b, and 12c are all 6 mm, and the width of the auxiliary rib groove 14a at the center of the mediate portion M and the width of the auxiliary rib groove 14b at the center of the shoulder portion S are all. The width of the lug groove was 3 mm and 6 mm. The evaluation results are shown in Table 1.

(Comparative Example 1)
In Example 1, the same tire was used except that the pattern 32 shown in FIG. 2 was adopted as the tread pattern. As the secondary rib groove, the secondary rib groove 14a of the mediate part on the inner side of the mounting and the secondary rib groove 12c of the mediate part on the outer side of the mounting were formed, but not formed on the shoulder part. The evaluation results are shown in Table 1.

(Comparative Example 2)
In Example 1, the same tire was used except that the pattern 31 shown in FIG. 3 was adopted as the tread pattern. As the auxiliary rib groove, the auxiliary rib groove 14b of the shoulder portion on the inner side of the attachment and the auxiliary rib groove 12a of the mediate portion on the outer side of the attachment were formed, but not formed in the mediate portion. The evaluation results are shown in Table 1.

  From the results shown in Table 1, the tire provided with the secondary rib groove of the present invention has a handling performance on an ice road surface, a snow road surface, and a dry road surface that is superior to that of the tires of Comparative Examples 1 and 2. I understand.

The top view which showed the tread pattern of this invention The top view which showed the tread pattern of the comparative example 1 The top view which showed the tread pattern of the comparative example 2

Explanation of symbols

10 Tread pattern 12a, 12b, 12c Main rib groove 14a, 14b Sub rib groove M Mediate portion S Shoulder portion

Claims (4)

An equatorial main rib groove formed on the equator, an inner main rib groove formed on the inner side of the equatorial main rib groove, and an outer main rib groove formed on the outer side of the equator main rib groove. has three main rib grooves consisting of the side from the central portion and the inner main rib grooves of Mediate portion formed between the inner main rib grooves at inner side than the equator the equatorial portion main rib grooves possess the main rib grooves than the narrower sub-rib groove in the central portion of the shoulder portion of the side, the equatorial portion main rib grooves than the device the outside device from not having or the equatorial portion main rib grooves sub rib groove outer The pneumatic tire is characterized in that the secondary rib groove is smaller than the secondary rib groove inside the apparatus than the equator main rib groove .   2. The pneumatic tire according to claim 1, wherein a width of the main rib groove is 5 to 12 mm, and a width of the sub rib groove is 0.8 to 4.5 mm.   3. The pneumatic tire according to claim 1, wherein no auxiliary rib groove is provided on the outer side of the equator portion. 4. Furthermore, it has a lug groove that intersects at least one of the main rib groove and the sub rib groove, and a block is formed by the main rib groove or the sub rib groove and the lug groove, and a sipe is formed in the block The pneumatic tire according to claim 1, wherein at least a part of the sipe is a three-dimensional sipe.

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