JPS6137504A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To maintain are excellent condition in cornering performance and noise feature without reducing draining efficiency and friction life during operation, by furnishing a tread rubber thich enough to regroove up to 1.5 to 3 times the depth of the main grooves. CONSTITUTION:While main grooves 10 whose depth d1 is 3-5mm. is preared on the treat surface, the tread rubber is furnished with thickness Dt which can be regrooved up to depth d2, 1.5-3 times the depth of the grooves D1. And, the thickness of the tread rubber Dt is made as Dt=d2+d3, where d2 is 1.5-3 times the depth of grooves d1, and d3 is the depth from the bottom of d2 to the tread side of the belt layer V. Thus, as the tread surface T wears in operation, the depth of main grooves can be regrooved up to d1, before the initial groove depth d1 reaches to the wear limitation, so that the tire can be used constantly in an excellent condition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire in which the relationship between the depth of the main groove and the thickness of the tread rubber is improved.

[Conventional technology]

Conventional pneumatic tires, particularly passenger car tires G, have a tread surface T with a depth d of 7, as shown in FIGS. 5 to 7.
．． Main grooves M with numbers 5 to 9II11 are arranged.

Conventional tires with main grooves M having such depths have excellent drainage performance in the initial stage of use due to their deep groove depth, but they are not satisfactory in terms of cornering characteristics and noise performance. In addition, as the tread surface T wears out with use and the groove depth becomes shallower, cornering characteristics and noise performance may become superior within a certain groove depth range (
Ru. Then, as the usage time continues and the wear of the tread surface T progresses and the groove depth becomes even shallower, the drainage performance deteriorates rapidly and the life of the tire ends.

In this way, the conventional tire G having the main groove M formed on the tread surface T by the vulcanization mold to the final groove depth d,
At present, it is impossible to avoid changes in the performance of tires as described above, depending on the state of wear of the tread surface during the use of the tire.

[Purpose of the invention]

The present invention was developed as a result of studies to solve the above-mentioned problems.

Therefore, an object of the present invention is to provide an excellent pneumatic tire that can be used with excellent performance by minimizing changes in groove depth during the use of the tire.

[Structure of the invention]

That is, in the present invention, a main groove having a groove depth dl of 3 to 51I11 is arranged on the trend surface, and the tread rubber thickness Dt can be regrooved to a depth dl that is 1.5 to 3 times the groove depth dl. The gist is a pneumatic tire characterized by a thick wall.

〔Example〕

Hereinafter, the present invention will be specifically described by way of examples with reference to the drawings.

1 to 3 show a pneumatic tire according to an embodiment of the present invention, FIG. 1 is a cross-sectional explanatory view with a part removed, FIG. 2 is an enlarged cross-sectional explanatory view showing the main parts of the same, and FIG. The figure is an explanatory front view.

In the figure, E is a pneumatic tire according to an embodiment of the present invention, in which a main groove lO having a groove depth d of 3 to 51 layers is arranged on the tread surface T, and the tread rubber thickness Dt is set to the groove depth. The thickness is such that it can be regrooved to a depth dl that is 1.5 to 3 times the depth dl.

The tread rubber thickness skin has the above-mentioned groove depth d.
, and from this dl the belt N
The sum of V and the dimension d3 up to the tread side, that is, Dt=d2+d3.

In addition, it is preferable to set the said d3 in the range of 2.5-4 cranes.

Therefore, as the tire E of the present invention is used, the tread surface T
By regrooving this main alo so that the depth becomes dl again before the groove depth dl at the beginning of use reaches the wear limit, the tire can be used with its various performances always in good condition. be able to.

The tire E of the present invention has a tread rubber thickness Dt of
Since the wall thickness is such that it can be regrooved to a depth dl that is 1.5 to 3 times the groove depth dl, the glue group of the main groove 10 described above has a thickness that is 1.5 to 3 times the initial groove depth dl. depth dl
It is possible to reach

As mentioned above, the reason why the groove depth d is set to 3 to 5 mm is because if the groove depth is less than 311 I, the drainage performance will deteriorate early due to wear of the tread surface T due to use, which is undesirable. Furthermore, if the groove depth exceeds 5.5 mm, cornering characteristics and noise performance will be less improved, and the merits of the tire of the present invention will be reduced.

In other words, by setting the groove depth dl within the range of 3 to 5 depths, cornering characteristics and noise performance can be improved compared to the conventional tires described above without impairing drainage performance.

Next, as described above, the groove depths d are arranged in order of 3 to 5 at the root j.

FIG. 4 is a diagram showing the relationship between groove depth and tire performance.

This data is the test result of 165SR13 or equivalent size, and specifically, the drainage performance is
JATMA braking test, cornering characteristics are based on a joint comparative study between 1980 and JARI cornering test, and noise performance is based on 1972 Technical Report 49-482. The horizontal axis is the groove depth, and the vertical axis is the above. Each performance is shown as an index.

From Figure 4, the groove depth becomes shallower due to wear during use.
It can be seen that when the groove depth is less than 31 cm, the drainage performance is reduced by 10% or more compared to the conventional tire.

Furthermore, if the groove depth exceeds 5 m+s, as is clear from Figure 4, the improvement in cornering characteristics will be less than 20%, and the improvement in noise performance will also be reduced, so that the merits of the tire of the present invention will be reduced. I understand.

Furthermore, the reason why the tread rubber thickness 01 is made to be regroovable to a depth dl that is 1.5 to 3 times the groove depth d as described above is because the regroovable depth dl is dl.
This is because if it is less than 1.5 times the tread rubber thickness, the tread rubber thickness becomes thinner than that of a conventional tire, and the wear life decreases, which is undesirable.If it exceeds 3 times, the tread rubber thickness becomes thicker. This is because, if the temperature is too high, the development property, weight, transfer resistance performance, etc. will decrease, which is not preferable.

Further, it is preferable to provide a regroove limit depth display means 20 in the main groove 10 in order to easily know the regroove limit depth d2 and prevent excessive cutting during regrooving.

In this embodiment, the regroove limit depth display means 2
0, as shown in FIG. 3, a plurality of holes 2o (4 locations) are bored in the main groove 1O at intervals of 1'1''A.

It is preferable that the depth of this hole 20 is set within a range of 1.5 to 3 times the above-mentioned d1, and the diameter thereof is set within a range of 3 to 6 mm.

Furthermore, in consideration of slip signs, the regroove limit depth display means 20 should be placed at at least 4 locations (1
It is preferable that the portions are arranged with a width of about 10 to 30++n) in the circumferential direction.

Furthermore, as another example, the regroove limit depth may be displayed numerically on the wall of the display means 20.

In addition, the beam pattern and lug pattern of the present invention.

Of course, the present invention can be applied to pneumatic tires having any tread pattern such as a rib/lug pattern or a block pattern.

〔Effect of the invention〕

As described above, in the present invention, a main groove having a groove depth dl of 3 to 5 ms is arranged on the tread surface, and the tread rubber thickness 01 is 1.5 to 3 times the groove depth d. depth d
2, the trend surface T wears out with use, and before the groove depth d at the beginning of use reaches the wear limit, this main groove lO is regrooved to a depth d.
By regrooving the tire so that it becomes 1, the tire can be used with its various performances always being good.

Therefore, during the period of use, the tire of the present invention can maintain its cornering characteristics and noise performance without deteriorating its drainage performance and wear life compared to conventional tires.

[Brief explanation of drawings]

1 to 3 show a pneumatic tight fitting according to an embodiment of the present invention, FIG. 1 is an explanatory view of the 11Ji plane with a part removed, and FIG. 2 is an enlarged explanation of the Lli plane showing the main parts of the same 1. 3 are explanatory front views, and FIG. 4 is a diagram showing the relationship between groove depth and tire performance. Moreover, FIGS. 5 to 7 show conventional tires, and FIG. 5 is a cross-sectional explanatory diagram with a part removed.
FIG. 6 is an enlarged 1lli plane explanatory view showing the essential parts of the same, and FIG. 7 is a front view explanatory view. 10...Main groove, '1゛...Tread surface.

Claims (1)

[Claims] A main groove having a groove depth d_1 of 3 to 5 mm is arranged on the tread surface, and the tread rubber thickness Dt is set to the groove depth d_1.
A pneumatic tire characterized by having a wall thickness that allows regrooving to a depth d_2 that is 1.5 to 3 times the depth _1.