JPH0354006A - Tire improved in antiskid characteristic - Google Patents

Abstract

PURPOSE:To improve the stopping performance on icy road and reduce damage in the road surface and generation of noise by specifying the relation between the hardness of tread rubber and the rubber pins protruding from the surface at different temperatures. CONSTITUTION:An antiskid tire is provided with rubber pins protuding form the tread surface. In this case, the hardness of the pins are set specified level. Namely, it is set to satisfy the relation expressed by the attached formula I, where B is the JIS hardness HS in the tread rubber at -5 deg.C, C the JIS hard ness HS in the rubber pins implanted at -5 deg.C, and B*, C* are the JIS hardness in them at 23 deg.C. It is thus possible to improve the stopping performance on icy road and reduce damage in the road surface and generation of noise.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a tire with improved skid resistance.

[Conventional technology] So-called spiked tires used on icy roads have spikes buried in the tread surface to prevent slipping, so they have excellent skid resistance, but when used on normal asphalt roads, the spikes scrape the road surface. This causes dust pollution, and the road surface becomes uneven, worsening steering stability.

Conventionally, from the viewpoint of improving this point, snow tires have been provided that ensure ice braking performance by lowering the hardness of the tread rubber to give it flexibility and increasing the area of contact with the frozen road surface.

[Problem to be solved by the invention] However, snow tires have considerably lower ice braking performance than spiked tires, and because they lack rigidity on regular roads, they give a feeling of instability and are not comfortable to ride. This is a problem in terms of abrasion resistance, and furthermore, when the belt is driven, the strain at the end of the steel cord of the belt becomes large, resulting in separation from the rubber, which poses a problem in terms of tire durability.

In this regard, Japanese Patent Application Laid-open No. 57-172803 proposes that spike bottles made of vulcanized rubber whose hardness changes depending on low and high temperatures are provided in the tread to protrude from the tread surface. We are proposing a tire with rubber spikes that improves friction performance when driving on general roads, and reduces road surface damage and noise when driving on general roads.

However, the reality is that even such tires with rubber spikes still have poor skid resistance compared to spiked tires.

Of course, if the hardness of the rubber spikes is increased, it can be made closer to a spiked tire, but if the hardness is made too high, it is not appropriate in terms of damage to the road surface and reduction of noise when driving on ordinary roads.

The purpose of this invention is to further improve the frictional force with the icy road surface, to achieve ice braking performance as close as possible to that of spiked tires, to prevent damage to the road surface when driving on ordinary roads, and to further improve durability. The object of the present invention is to provide a tire with improved skid resistance and good properties such as abrasion resistance and durability.

[Means for solving the problem] As mentioned above, in order to achieve good ice braking, it is basically possible to achieve this by using rubber pins, but on the other hand, it is possible to achieve good ice braking by using rubber pins, but on the other hand, it is possible to achieve good ice braking by using rubber pins. It is possible to lower it.

However, if the rigidity is too low, the riding comfort (flaky feeling) and distortion at the end of the steel cord of the belt will increase when driving on general roads, and separation from the rubber will be promoted. It is also unfavorable from the viewpoint of realizing snow braking characteristics. However, even if the height is set too high, there is a limit to the fact that the heat generated in this part promotes separation between the steel cord and the rubber of the belt.

Furthermore, even if the rigidity of the tread rubber is kept to a certain level, an important issue is determining the hardness of the rubber pins that will exhibit good ice braking in relation to the tread rubber.

In view of this, the present invention provides a skid-resistant tire in which a rubber pin is formed to protrude from the tread surface.The JIS hardness HS of the tread rubber at -5°C is B, and the JIS hardness HS of the rubber pin to be driven in at -5°C is C123°C. A skid-resistant tire was developed in which the JIS hardness HS of the tread rubber and rubber pin was B1C8, and a rubber pin with high rubber hardness satisfying the following formula was driven into the tread surface.

C-B>15 50<B<70 8HSa=B-B"<7 ΔHSc=C-C">5 [Function] Therefore, the JIS hardness C of the rubber pin at -5°C and 2
Hardness difference Δ from JIS hardness C'' of rubber pin at 3℃
By specifically setting HSc to ΔHSc=C-C''>5, friction performance is improved when driving on frozen roads and damage to the road surface is simultaneously prevented when driving on ordinary roads, and ride comfort (fluctuation! ig) is improved.In the case of ΔHSc<5, there is little change in hardness between room temperature and low temperature, so increasing the hardness at -5°C will improve the friction performance when driving on frozen roads. , it is not good in terms of road surface damage and ride comfort, and conversely, if the hardness C''' at 23° C. is lowered, the effect of friction performance becomes poor. The JIS hardness of the rubber pin at 23℃ is 70.
In the above, it is desirable to set the upper limit to a hardness that does not cause scraping of the asphalt road surface.

The present invention also improves the hardness of the tread rubber by 50 B and 70 B.
And hardness B at -5℃ and hardness B at 23℃
”, the hardness difference ΔHS8 is set as ΔHS.=B−Bゞ7,
In addition, by setting the hardness difference between the rubber pin and the rubber pin to C-B>15, the friction force on icy roads can be improved compared to conventional snow tires and rubber spike tires, and it is also possible to drive on general roads. However, it also has good wear resistance and improved durability.

[Example] A rubber pin with the same shape as a metal spike pin was made,
A trial tire of size 6.50R16 10PH shown in Table 1 was manufactured by driving the same number of tires into the tread surface. Next, in order to evaluate the characteristics of this prototype tire, various tests were conducted regarding ice performance, snow performance, abrasion resistance, belt durability, and ride comfort. The results are shown in Table 1.

For comparison, snow tires, metal spike tires, and tires with rubber pins of the same size and having the hardness conditions shown in the same table were also tested.

Ice performance and snow performance are based on actual vehicle tests on ice burns and snow at -8°C. In both cases speed 4
The reciprocal of the stopping distance when driving at 0 km/h and suddenly braking was expressed as an index, with the snow tire of Comparative Example 1 set as 100. The larger the value, the better.

Wear resistance is 50 under normal road driving conditions on the test course.
Calculated from residual wear after traveling 0.00 km.

Bell 1/Durability was determined by running the tire in a bench drum test until it failed, and the distance traveled was expressed as an index with Comparative Example 1 set as 100.

Ride comfort was evaluated on a five-point scale based on the feeling of unevenness, unsteadiness, etc. during general driving on a test course.

5 indicates very good, 4 indicates good, 3 indicates fair, 2 indicates poor, and 1 indicates very poor.

(The following is a blank space) As can be understood from Table 1, the tire of the present invention has significantly improved ice performance compared to other snow tires. Furthermore, even when running on general roads, it has been found that the wear resistance, belt durability, and ride comfort are also good.

[Initial Effects] As stated in Section 2 above, this invention not only improves ice braking performance by using rubber pins driven into the red rubber surface and reduces road surface damage and noise, but also improves the following effects in relation to the tread rubber: While adjusting the rigidity, the ice braking performance has been significantly improved, and it also has a good balance of wear resistance, durability, and ride comfort even when driven on regular roads. It was possible to provide a tire with improved skid properties.

Claims (1)

[Claims] (1) In a skid-resistant tire in which rubber pins are formed protruding from the tread surface, the JIS hardness HS at -5°C of the tread rubber is B, the JIS hardness HS at -5°C of the rubber pin to be driven is C, the tread rubber at 23°C, The JIS hardness HS of the rubber pin is B^* and C^*, respectively.
A tire with improved skid resistance, characterized in that a rubber pin with high rubber hardness that satisfies the following formula is driven into the tread surface. C-B>15 50<B<70 ΔHS_B=B-B^*<7 ΔHS_C=C-C^*>5