JPS60189608A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To improve resistance to abrasion, braking property, draining property and the like by forming the captioned rib type pneumatic tire for bus and the like through providing each stone-bite preventive convex stripe of a predetermined shape in a zigzag groove, which has a predetermined point height on a tread, and in a bent-up part of the groove. CONSTITUTION:At least three zigzag grooves M are provided in a tread part, and the ratio of a point height HC for the tread center part TC side groove MC to the tread width W is set at 6-10%, while a stone-bite preventive convex stripe T0 is arranged in each bent-up part MC0. The ratio Hto/Hg of the height Hto for said convex stripe T0 to the depth Hg of the groove MC, the ratio Wto/ Wmc of the convex stripe width Wto to the groove width Wmc, and the ratio Pto/PC of the projection length Pto for the convex stripe T0 to the groove pitch length PC are respectively set at 0.2-0.4, 0.2-0.4 and 0.15-0.25. Due to this structure, tire performances such as resistance to abrasion, braking property, draining property and the like can be improved.

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 for high-load vehicles such as Riptive trunks, lotuses, and light trucks.

[Conventional technology]

Conventionally, Kaributaibu's pneumatic tires for high-load vehicles have been designed to prevent stones from getting into the grooves by devising the structure of the grooves that make up the tread pattern.
Attempts have been made to facilitate the release of trapped stones.

However, none of the conventional methods has improved wear resistance, which is important for the performance of this type of pneumatic tire.

At present, it is difficult to satisfy braking performance, drainage performance, etc.

[Purpose of the invention]

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

Therefore, the object of the present invention is wear resistance, :l;+J dynamics.

An excellent feature that prevents stones from getting stuck in the grooves that make up the I/Red pattern and makes it easier to release the stuck stones without impairing important performance of this type of pneumatic tire such as drainage performance. Our objective is to provide pneumatic tires with

[Structure of the invention]

In other words, the present invention arranges at least three zigzag-shaped grooves continuous in the circumferential direction of the tire at intervals in the width direction on the tread surface of the tire, and a part of the tread center side behind the zigzag-shaped grooves. Stone bite prevention protrusions are arranged at each bent part of the groove located at point high l-1 (c) of the groove located at a part of the tread center.
The ratio of mowing to W is 6% to 10%, and
Ratio of the height Hto of the ridge to the depth H of the groove!
tHto/Hg +1.2 to 0.4, protrusion width Wt
The ratio of o to the groove width Wmc of the groove W to / W
mc is 0.2-0°4, and the ratio Pto/Pc of the projected length Pto of the protrusion to the pitch length Pc of the groove is 0.1.
The gist thereof is a pneumatic tire characterized by having a diameter of 5 to 0.25.

[Embodiments of the invention]

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

1 to 5 show each embodiment of the present invention, FIG. 1 is a developed view of a tread pattern of a pneumatic tire according to the first embodiment, and FIG. 2 is a cross section taken along the line A-A in FIG. 1. An enlarged explanatory view (main part only), Fig. 3 is an enlarged cross-sectional explanatory view showing the longitudinally developed shape of the stone-biting prevention convex strip, and Fig. 4 is an expanded view of the trend pattern of the pneumatic tire according to the second embodiment. FIG. 5 is a developed view of a tread pattern of a pneumatic tire according to a third embodiment.

Pneumatic tires according to each embodiment of the present invention are shown in FIGS.
As shown in FIG. 5, at least three zigzag tiMs continuous in the circumferential direction of the tire are arranged at intervals in the width direction on the tread surface of the tire T, and among these zigzag iMMs, the tread center A stone bite prevention convex line To is arranged at each bent part Mco of the groove Mc located on the Tc side of the tread center, and is carved in the trend width W of the point hide Hc of the groove Mc located on the Tc side of the tread center part. 6% to 10%
%, the ratio Hto/Hg of the protrusion height Hto of the stone bite prevention protrusion '1'o to the depth Hg of the groove Mc is 0.2 to O', 4, and the protrusion width Wto of the groove Mc is Ratio W LO/W mc to groove width Wmc is 0.2 to 0
．． 4. Ratio Pto/Pc of the projected length Pto of the protrusion To to the pitch length Pc of the groove Mc.

is set to 0.15 to 0.25.

Furthermore, in the actual embodiment, the ratio of the point height I of the groove Ms located on the shoulder part 'I's side of the zigzag groove M to the point height I and the width W of the groove 1 is 2% to 2%. The groove width Wm of the two left and right zigzag-shaped grooves Mc, which are set in the range of 4% (-7), is set to 4% (-7).
The proportion of the groove width Wms of the groove Ms located on the 1'1's side of the shoulder c and the shoulder part aligned with the tread width W is set to a range of 5% to 8%. The pitch length Ps of 11 ■ Ms located at '.
)4, the ratio Pc/Ps is set to twice.

To further explain this structure, in the first embodiment of the present invention shown in FIG. A total of three grooves are arranged at intervals on both sides of the shoulder part Ts side of this groove Mc, and among these zigzag-shaped /i'6M, the groove Mc located at the trend center part 'I''C is In this embodiment, as shown in the drawings, bent portions Mf are further formed at the tops of the zigzag shape and at each of the bent portions MC and O. 'Fo is placed.

And the height Ht of the stone bite prevention protrusion To.

Ratio 1 (to /
I-1g (1, 33, above of the protrusion width Wto?M M
Ratio of c to groove width Wmc W to / W mc
0.26. The ratio Pto/Pc of the projected length Pto of the protrusion To to the pinch length Pc of the groove Mc is set to 0.21, and the above-mentioned ? m Mc point high 1i
(Ratio Hc/W of c to tread width W is 9%, groove M
Ratio i of point hide Hs of S to tread width W
(s/W is 3%, the ratio of the groove width Wmc of the groove Mc and the groove width Wms of the groove Ms to the trend width W +nc /
Both W and W m s / W are 6%, and the ratio of the pitch length Ps of the groove Ms to the pitch length Pc of the groove Mc I) C/
Double Ps, rib width Wr of part of Sikorda Ts side rib l
The ratio W1./W to the tread width W is 20%.

As mentioned above, the tread center part 1'c, the tops of the zigzag grooves Me arranged in
By forming f, the tread center part “I”
It is possible to further improve the stone-biting phenomenon prevention effect of the zigzag grooves M (, -) arranged at c.Furthermore, by forming the bent portion Mr as described above, the tread center part = f' The rapid variation in the rib width of the rib Rc on the c side can be significantly alleviated, abnormal wear such as rib punching can be prevented, and the point high C of the groove Mc can be substantially increased, The braking effect can be further improved, and the appearance of the trend pattern can also be improved.

Therefore, the point high l−Hf of each bending portion Ml
The ratio Hf of the groove Mc to the point hide Hc
/Hc is desirably set in the range of 0% to 30%, preferably 15% to 30%, and the ratio P of the pitch length Pf of the bent portion Mf and the pitch length Pc of the groove Mc
f/Pc from 0.1 to 0.25, preferably from 0.15 to 0
, 25 is desirable.

In this example, the Hf/Hc was 26%, P
f/Pc is set to 0.21.

Next, a second embodiment of the present invention shown in FIG. 4 will be briefly described.

In this embodiment, the zigzag groove M has two zigzag grooves MC positioned at the tread center part Tc, and two zigzag grooves MC arranged at intervals on both sides of the shield part Ts of the groove Mc. There are a total of four zigzag grooves Ms arranged on the left and right, and the back of these zigzag grooves M.
), the two left and right grooves Mc located on the Tc side of the trend center part are provided with grooves located at the tops of the zigzag shape, that is, at each 41'i' curved part Mco, as in the first embodiment described above. Further, a bent portion Mf is formed, and the stone bite prevention l-projection strip 1゛o is arranged in this bent portion Mf.

And the convex line 1f of the stone bite prevention convex line 'FO' (iS IIL
(The ratio of 1 to the depth Hg of the groove Mc is 11to/
I-1g to 0.33. The ratio W to / W me of the protrusion width Wto to the groove width Wn+c of the groove Mc is set to 0.
26. The ratio Pto/Pc of the projected length Pto of the protrusion 'l'0 to the pitch length tl'c of the groove Mc is 0.21.
Furthermore, point hide 11 of the groove Mc
(1 to 7% of the ratio Hc/W to the let width W, 2% of the λ ratio IIs/W to the tread width W of the point hide Hs of the groove Ms, 1 of the groove width Wms of the groove Ms bow/
The ratio Wms/W to 1 in the width W is 6%, l+iM
c(+) Ratio of groove width Wmc to tread width W m
c/W by 5%, the pinch length Ps of the groove Ms, and the groove Mc
The ratio Pc/Ps of the pinch length Pc is doubled, the ratio Wr/W of the rib width Wr of the shoulder part 1's side rib Rs to the tread width W is 20%, Hf/Hc is 21%, Pf/
Pc was set to 0.15.

Next, a third embodiment of the present invention shown in FIG. 5 will be briefly described.

In this embodiment, the zigzag groove M is similar to the first embodiment described above, with a single zigzag groove Me located at a part of the 1-red center "I"C. A total of three zigzag-shaped grooves Ms are arranged on both sides of the Ts side of the shoulder part of the ?M Mc.
The stone bite prevention protrusions To are arranged at each bending portion Mco of aMc located in the tread center portion 1'c.

In this embodiment, as in the first and second embodiments described above, #M located at the tread center part '1'C
The bent portion Mf is positioned at each bent portion Mco of c.
is not formed.

and the height Ht of the stone bite prevention protrusion To.

Depth I of said groove Mc of (ratio to g Hto/H
g to 0.33. Groove width Wmc of the groove Mc with the protrusion width Wto
The ratio W to / W mc to 0.26. Pinch length P of the groove Mc with projected length Pto of the protrusion T, 0
The ratio Pto/Pc to c is 0.21.

In addition, in the actual embodiment described above, the longitudinally developed shape of the stone bite prevention convex strip 1'o is constituted by a combination of three curved surfaces, as shown in Part 31, and these three curved surfaces are radius of curvature R (R1, R2, R3)
is the range of R/ II to =・1.5 to 2.5 (H
It is desirable that to be the height of the protrusion of the stone bite prevention 11 - the protrusion of the protrusion '1゛o).

In the actual example, the radius of curvature R is R/Ht
Let o=2.0.

[Experiment example]

Examples of experiments conducted to confirm the effects of the present invention described above will be explained below.

[Experiment example 1] Tire of the present invention: the pneumatic tire of the first embodiment.

Comparative tire: The pneumatic tire of the first example,
A tire in which the stone bite prevention protrusion To is not arranged in the groove Mc.

Conventional Tie-V: A pneumatic tire in which three continuous zigzag grooves are arranged in the tire circumferential direction at intervals in the width direction on the tire tread.

was used to evaluate the number of stones stuck into the groove and the number of stones that fell off.

The specifications and test conditions of the tire used in Experimental Example 1 are as follows.

Tire size: 10.00R2014PR Internal pressure:
8. Okg/CR & Rim: 7.50V x20 Vehicle: 2-D-D dump (10Lon product) How many loads:
10 ton loading measurement method: Drive a certain distance on a course consisting of 18% gravel road and 82% paved road to measure the number of stones caught in the groove, then drive a certain distance on paved road to measure the number of stones caught in the groove. Measure the number of dropouts.

As a result of the experiment, 11 results were shown in Table 1 below.

From this experimental result, it was found that the tire of the present invention can reduce the number of stones stuck into the groove by 1/:ronino compared to the i-Iu 1 Kokuiya, while reducing the number of stones stuck (77) falling out. It can be seen that it can be increased by more than three times.

In addition, compared to conventional tires, the comparative example 4 tires can significantly reduce the number of stones stuck into the groove, while also significantly increasing the number of stones stuck in the groove that fall off. .

Furthermore, in the above experiment, the position and number of stone bites were investigated, and the results shown in Table 2 below were obtained.

From this result, it can be seen that there is a lot of stone encrustation at the bent part Mco of the groove Mc located at part '1'C of the tread center, and the stone encrustation prevention protrusion 1'o was arranged at this bent part Mco. It can be seen that in the case of the tire of the present invention, the number of stone bites 1LI11 is reduced, and the stone shedding rate is also better than that of the comparative tire in which the stone bite prevention protrusion ``o'' is not arranged on the bending part Mco.
In the present invention, the stone-bite prevention protrusion To is arranged at the bent portion Mco of the groove Mc located in the tread center portion Tc.

In addition, in parallel with the above-mentioned experiment, the relationship between the ratio Hto/Ha of the height Hto of the stone-biting prevention protrusion '1o to the depth Hg of the 11i Mc and the number of stone bites was investigated. As a result, Hto / ■1 [! is 0.2 less than 7S
In No. 1, only the effect similar to that of the comparative example tire in which the stone-biting prevention protrusion 'f'0 is not provided, and tl to / I (
When I: exceeds 0.4, the rate of biting small stones increases.4
- It turned out that. Therefore, Hto/HIX is 0.
It has been recognized that setting the value in the range of 2 to 0.4 is most effective in improving the effect of preventing stone bite.

[Experiment example 2] Tire of the present invention: the pneumatic tire of the first embodiment.

Comparative tire: The pneumatic tire of the first example,
A tire that does not have stone spout prevention protrusions 'T'' o arranged in the groove Mc.

Conventional tire: A pneumatic tire in which zigzag grooves are arranged on the tire tread at three intervals in the width direction and continuous in the circumferential direction.

Wet braking performance was evaluated using

The specifications and test conditions of the tire used in Experimental Example 2 are as follows.

Tire size: 10.0OR2014PIl Internal pressure:
7.25 kg/cta rim near, 50V'
X20 vehicle: 2-D flat body B ton vehicle load: empty road surface, two wet road surface measurement methods: /! ii Braking distance on regular road surface, JI
Measured by the method of SD1013.

As a result of the experiment, the experimental results shown in FIG. 6 were obtained.

From this experimental result, it was found that the tire of the present invention can improve the wet braking performance compared to the conventional tire, while the tire of the present invention can exhibit the same wet braking performance as the comparative tire. do.

[Experimental Example 3] Using the pneumatic tire of the first embodiment,
(The ratio of c to throat width WI, Hc, /W was varied to evaluate wear resistance and braking performance.

As a result of the experiment, the experimental results shown in Fig. 7 (al and (bl) were obtained.

Figure 7+al shows the ratio (%) of the point hide Hc of the groove placed on the part side of the trend center (17) to the 1 to red width W, which is applied to the pneumatic tire of the first embodiment.
Fig. 7 tb) shows the relationship between the wear resistance (index) and the tread of the pneumatic tire of the first embodiment (-) where the point on the red center part side is iiG: Zui, the groove point '1tif It shows the relationship between the ratio (%) of W and wet braking performance (index).

From this experimental result, if the ratio Hc/W to the tread width W of Point Hyde LLC is 6%, there is no noticeable improvement in wet braking performance, while when Hc/V#+<1
It can be seen that if it exceeds 0%, wear resistance decreases.

Therefore, in order to improve wet road braking performance, that is, wet braking performance without impairing wear resistance, the ratio Hc/ W should be set in the range of 6% to IO%, more preferably 7% to 10%.
It turns out that it is desirable to set it within the range of %.

[Experimental Example 4] Next, using the pneumatic tire of the first embodiment, the groove width Wms of the groove Ms located on the shoulder part '1's side and the groove width Wms of the groove Ms located on the tread center part Tc side (37 Mc groove width W
Wear resistance and wet braking performance were evaluated by varying the ratio of mc to tread width W.

As a result of the experiment, we obtained the experimental results shown in Figure 8fa) and fbl.

FIG. 8 (al is the groove width W of 'hVj located on a part of the tread center side in the pneumatic tire of the first embodiment.
Figure 8 shows the relationship between the ratio (%) of mc to the trend width W and the wear resistance. Groove width Wllll (: Ratio (%) to tread width W
) and wet braking performance.

From this experimental result, part of the shoulder 1's (itlla
l: The groove width Wms of the located groove Ms (7) and the groove width Wmc of the groove Mc located on the center part T'c side of the tread width W is less than 5%: lL So I
・It is clear that no significant improvement in braking performance is observed, and that abrasion resistance decreases when it exceeds 8%.

Therefore, in order to improve the wet road braking performance (i.e., wet braking performance) without impeding wear resistance, the groove width Wms and the groove width Wmc must be adjusted to 1 L throat width. It can be seen that it is desirable to set the ratio to W in the range of 5% to 8%.

[Experimental Example 5] Furthermore, using the pneumatic tire of the first embodiment, the pitch range Ps of the groove MS located on the shoulder part Ts side, and the groove position Ps located on the tread center part '1'c side. Mc,
The ratio Pc/Ps of the pitch length Pc was varied to evaluate wear resistance and damping performance.

As a result of this experiment, it was found that increasing the value of Pc/Ps improves wear resistance, but reduces wet braking performance, and conversely increases Pc/Ps.
If the value of /Ps is made small, the wear resistance will decrease and abnormal wear will easily occur on the rib Rc on the T'c side of the tread center, so the value of 17c/Ps is 2.0, that is, the shoulder part The ratio Pc/Ps of the pitch length Ps of the groove Ms located on the 1's side and the pitch length Pc of '/IIMc located on the tread center part Tc side is preferably set to twice.

The specifications and test conditions of the tires used in Experimental Examples 3 and 4.5 described above are as follows.

[Actual vehicle wear resistance test]

Tight size: IO,0OR2014PR Internal pressure:
7.25kg/ct Rim near, 50V internal pressure
: 7, 25 kg/C+4 rim near, 50V
x20 Load capacity: Empty vehicle measurement method: /Si! Braking distance on smooth road surface 1isl+
was measured by the method of JI501013.

〔Effect of the invention〕

As described in the present invention, at least three zigzag grooves continuous in the circumferential direction of Yu/Eid are arranged at intervals in the width direction on the Mi'i song of Thailand 1, and these zigzag grooves are arranged at intervals in the width direction. A stone 1111"J block + L protrusion is arranged at each bent part of the groove located on the part side of the tre 71 center. The ratio of the point height 1ilc of the groove to the tread 'Ibi W is set to 6% to 10%, and the stone bite prevention [1-height H of the ridges]
The depth of the groove to is Hg&i and the ratio Hto/
Hg from 0.2 to 0.4. Groove width W of the groove of the protrusion width Wto
The ratio W to / W mc to m c is 0°2 to 0.4. The ratio Pto/Pc of the projected length Pto of the protrusion to the pinch length Pc of the groove is 0.15 to 0°25.
Therefore, it does not impede the important performance of this type of pneumatic tire such as wear resistance, braking performance, drainage performance, etc.
It is possible to prevent stones from getting stuck in the grooves that make up the tread pattern, and to make it easier to release the stuck stones.

[Brief explanation of the drawing]

1 to 5 show each embodiment of the present invention, FIG. 1 is a developed view of a tread pattern of a pneumatic tire according to the first embodiment, and FIG. 2 is a cross section taken along the line A-A in FIG. 1. An enlarged explanatory view (principal parts only), Fig. 3 is an enlarged cross-sectional explanatory view showing the longitudinally developed shape of the stone bite prevention convex strip, and Fig. 4 is a developed view of the 1-red pattern of the pneumatic tire according to the second embodiment. , Figure 5 is the third
FIG. 6 is a trend pattern development diagram of pneumatic tires consisting of examples, and FIG. 6 is a diagram showing conventional tires, comparative tires,
A diagram showing the results of measuring the braking performance of the tire of the present invention, 7th ti! I+a+ is a diagram showing the relationship between the wear resistance and the ratio (%) of the point hide Hc of the groove located on a part of the trend center side to the tread 1/1 depression W in the first embodiment, No. 71<1 ( bl corresponds to the first embodiment,
Point hide T in the groove located on one side of the trend center
(Figure 8 shows the relationship between the ratio (%) of c to the tread width W and the wet braking performance. (al is the groove width Wmc of the groove located on a part of the tread center side in the first embodiment
FIG. 8(b) is a diagram showing the relationship between the ratio (%) to the tread width W and the wear resistance. FIG. , l-L
-G) It is a diagram showing the relationship between the ratio (%) to the width W and wet braking performance. T...tire, M...zigzag r1■, M(,
...Groove located on one side of the tread center, Tc...
A part of the tread center, Mco...a bent part of the groove located on the side of a part of the tread center, To...stone bite prevention 11. Convex stripes. Figure 1 Figure 3 Figure 4 Figure 5 Figure 6 Wet braking index Figure 7 (a) 0 2 4 6 81012 ) Ic/W (%) 8 1-1 (a) 0 2 4 6 8 10 Wmc/W, (Part) Fig. 7(b) 0 2 4 6 8 10 12 Hc,'W (Part) Fig. 8(b) Wmc/W (%)

Claims (1)

[Claims] At least three zigzag grooves continuous in the circumferential direction of the tire are arranged on the tread surface of the tire at intervals in the width direction, and behind these zigzag grooves, on a part side of the trend center. A bulky point high I located on a part of the tread center side is formed by arranging stone bite prevention protrusions at each bent part of the groove.
・IJr. The ratio to the tread width W is (1% to 10%, and the height Ht OO of the stone-biting prevention protrusion) i! The ratio Hto/Hg to the depth Hg of the iJ groove is 0.2~(
1,4. The ratio of the ridge width Wto to the groove width WmcL'' of the groove is 0.2 to 0.4, the projected length of the ridge PloO) the ratio P to the pitch length Pc of the groove.
A pneumatic tire characterized in that to/Pc is 0.15 to 0.25.