CA1319600C - High internal pressure type heavy duty pneumatic radial tires - Google Patents
High internal pressure type heavy duty pneumatic radial tiresInfo
- Publication number
- CA1319600C CA1319600C CA000569783A CA569783A CA1319600C CA 1319600 C CA1319600 C CA 1319600C CA 000569783 A CA000569783 A CA 000569783A CA 569783 A CA569783 A CA 569783A CA 1319600 C CA1319600 C CA 1319600C
- Authority
- CA
- Canada
- Prior art keywords
- tread
- curvature
- tire
- internal pressure
- radius
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/0083—Tyre tread bands; Tread patterns; Anti-skid inserts characterised by the curvature of the tyre tread
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/01—Shape of the shoulders between tread and sidewall, e.g. rounded, stepped or cantilevered
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/03—Tread patterns
- B60C11/0327—Tread patterns characterised by special properties of the tread pattern
- B60C11/0332—Tread patterns characterised by special properties of the tread pattern by the footprint-ground contacting area of the tyre tread
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Tires In General (AREA)
Abstract
HIGH INTERNAL PRESSURE TYPE
HEAVY DUTY PNEUMATIC RADIAL TIRES
ABSTRACT OF THE DISCLOSURE
High internal pressure type heavy duty pneumatic radial tires are disclosed, which each comprise a tread.
Each tire is formed and vulcanized in a mold, and the tread has an outer contour inside the mold, which outer contour sectionally consists of a curve halving a positive radius of curvature with a curvature center on a side of a tire axis at a central portion of the tread extending between points "m" being oppositely separated from a tread (TW/2) center by 0.64 to 0.85 of a half of a width of the tread and a curve having a negative radius of curvature with a curvature center on a side opposite to the tire axis at tread shoulder portions axially outside said points "m". The negative radius of curvature has an absolute value of 1 to 30 of the tread width (TW). A tread shoulder edge drop-correcting value H3 is in a range from 0.05 to 0.04 of H1 which is a radially dropped amount of an edge of the tread which would be formed in a mold sectionally having a single radius of curvature and the entire outer contour of the tread radially outwardly expands from that inside the .
mold by applying a use internal pressure to the tire to form the outer contour of the tread at a single radius of curvature.
HEAVY DUTY PNEUMATIC RADIAL TIRES
ABSTRACT OF THE DISCLOSURE
High internal pressure type heavy duty pneumatic radial tires are disclosed, which each comprise a tread.
Each tire is formed and vulcanized in a mold, and the tread has an outer contour inside the mold, which outer contour sectionally consists of a curve halving a positive radius of curvature with a curvature center on a side of a tire axis at a central portion of the tread extending between points "m" being oppositely separated from a tread (TW/2) center by 0.64 to 0.85 of a half of a width of the tread and a curve having a negative radius of curvature with a curvature center on a side opposite to the tire axis at tread shoulder portions axially outside said points "m". The negative radius of curvature has an absolute value of 1 to 30 of the tread width (TW). A tread shoulder edge drop-correcting value H3 is in a range from 0.05 to 0.04 of H1 which is a radially dropped amount of an edge of the tread which would be formed in a mold sectionally having a single radius of curvature and the entire outer contour of the tread radially outwardly expands from that inside the .
mold by applying a use internal pressure to the tire to form the outer contour of the tread at a single radius of curvature.
Description
13196~0 62-155,397 HIGH INTERNAL PRESSURE TYPE
HEAVY DUTY PNEUMATIC RADIAL TIRES
The present invention relates to high internal pressure type heavy duty pneumatic radial tires. More specifically, the invention relates to high internal pressure type heavy duty pneumatic radial tires which are to be served under higher internal pressures and higher loads as compared with conventional heavy duty pneumatic radial tires for use in trucks, buses, etc.
and which have improved shoulder edge drop wear resistance and uneven wear resistance.
Conventional heavy duty pneumatic radial tires used in trucks, buses, etc. are produced by shaping an outer contour of a tread inside a mold at a single radius of curvature as viewed in radial planes and effecting vulcanization there, and are run under application of a use internal pressure of about 7.25 kg/cm2. These tires have especially no problem in terms of uneven wear resistance.
However, if conventional heavy duty pneumatic radial tires of this type for use in trucks, buses, etc.
were employed under higher load, it was revealed that the tires had troubles in uneven wear resistance.
Under the circumstances, the present inventors 13196~0 have tried to develop heavy duty pneumatic radial tires to be used under loads higher than those in the case of conventional ones, and proceeded their studies with respect to the following two points:
(l) An air volume inside a tire is increased.
(2) A use internal pressure of a tire is increased.
As a result, they found that the above item (l) can be realized by making a diameter of a use rim smaller, while with respect to the item (2), a tire can be designed to withstand such a high use internal pressure of 9.0 to 12.0 kg/cm2.
When a high internal pressure type heavy duty pneumatic radial tire having the outer contour of a tread formed at a single radius of curvature, inside a mold, as in the case of heavy duty pneumatic radial tires to be used in trucks, buses, etc., was vulcanized inside the mold and actually run under application of a high internal pressure (9.8 kg/cm2) on a test course, its uneven wear resistance was not satisfactory. Then, a cause was investigated, and the following fact was revealed. That is, when a high internal pressure (9.8 kg/cm2 or more) is applied to a tire after vulcaniza-tion, an edge of a tread of the actual tire is radially inwardly located by a vertical distance from ,~' i3~9~
an edge of a tread having an imaginary single radius of curvature expected at a shoulder of the tread. In this way, it is seen that application of such a high inter-nal pressure to the tire makes the outer contour of the tread shoulder portion to have an unexpected radius of curvature which is smaller than the radius of curvature at the central portion of the tread.
Turning to a ground contact shape (foot print) of the tire to which load is applied, the fol-lowing fact has been made clear. That is, edge cornersof the ground contact area are round so that the ground contact length of the edge of the foot print is shorter. Consequently, the tread is dragged at the edges of the ground contact area, and thus the edges are worn at an early stage, which leads to uneven wear-ing such as shoulder drop wearing.
Further, it was analyzed that when the tire is inflated at a high use internal pressure, the outer contour of the tread expands radially outwardly from that of the tread inside the mold. At that time, since the use internal pressure is very high, the center por-tion of the tread between almost 1/4 points, that is, points which are axially separated from a tread center h;~
~ ~. . . ~ "
1319~00 by a distance equal to about 1/2 of a half of the width of the tread more expands radially outwardly than the tread shoulder portion. Consequently~ the contour of the tread shoulder comes to have a second radius o~
curvature due to the application of the internal pressure to cause a radial drop of the tread edge.
Such a phenomenon is not seen in conventional heavy duty pneumatic radial tires of this type to be used for trucks, buses, etc. at low internal pressures.
It is an object of the present invention to provide high internal pressure type heavy duty pneumatic radial tire~ which have uneven wear resistance such as shoulder drop wear re~istance greatly improved, when in use at an internal pressure 19.0 to 12.0 kg/cm2) higher than in the case of conventional heavy duty pneumatic tires ~or use in trucks and buses, by making a dropped amount of the outer ~ontour of the tread shoulder smaller than that o~ the tread shoulder having a single radius oE curvature and thus preventing the ground contact len~th of edges o~ the tread ~n contact with ground under load from becoming shorter.
In order to attain the above-mentioned object, according to the present invention, the outer contour of the tread at a central portion between points axially separated f rom the tread center by a distance ~alling in a range from 0.64 to 0.85 of a halE of the ,~,,;,,, width o~ the tread inside a mold has a posi-tive radius of curvature which has a curvature center o:l a side of an axis oE the tire, while the contour o~ the tread at each o~ the shoulder portions located axially outside the above points inside the mold have a negative radius oE curvature which possesses a curvature center on a side opposite to the tire axis while the negative radius of curvature has an absolute value in a range from 1 to 30 times the width of the tread. As a result, an amount for correcting a tread shoulder drop (hereinafter referred to as "tread shoulder edge drop-correcting amount") may be in a range ~rom 0.05 to 0.4 time an amount of a shoulder drop occurring in the case of a tire with a tread having a crown of a single radius of curvature inside a mold, whereby the entire outer contour of the tread expands radially outwardly from that o~ the tread inside the mold corresponding thereto through application of a use internal pre3sure to have a single radius of curvature.
~ ccording to the present invention, despite that the use internal pressure is high, the foot print is made almost rectangular by enlarging the ground contact length of the tread edges. Consequently, uneven wear resistance can be improved to a large extent.
These and other objects, features, and advantages of the present invention will be appreciated upon reading of the following description of the invention when taken in conjunction with the attached drawings, with the understanding that some modiflca-tions, variations, and changes of the same could be made by a person having an ordinary knowledge of the art to which the invention pertains, without departing from the spirit of the invention or the scope of claims appended hereto.
For a better understanding of the invention, reference is made to the attached drawings, wherein:
Fig. 1 is a schematic sectional view illustrating an outer contour of a tread of a tire according to the present invention inside a mold;
Fig. 2 is a schematic sectional view of the outer contour of the tread of the tire according to the present invention when being inflated at a use internal pressure;
Fig. 3 is a schematic view showing that the entire outer contour of the tread of the tire according to the present invention expands radially outwardly from that of the tread inside the mold when the tire is inflated at a use internal pressure;
Fig. 4 is a schematic sectional view in which outer contours of treads of tires in the present invention, and Comparative Examples 1 and 2 are shown by a solid line, a dotted line, and a one dot-chain line, 13196~0 respectively, under application of a use internal pressure;
Fig. S is a foot print showing a ground contact shape of the tread of the tire according to the present invention;
Fig. 6 is a schematic sectional view illustrating an outer contour of a tread of a tire in Comparative Example 2 inside a mold;
Fig. 7 is a schematic sectional view illustrat-ing the outer contour of the tread of the tire in Comparative Example 2 when the tire being inflated at a use internal pressure;
Fig. 8 is a foot print of the tire in Comparative Example 2;
Fig. 9 is a schematic sectional view illustrat-ing the outer contour of a tread of a tire in Comparative Example 1 inside a mold;
Fig. 10 ia a schematic sectional view of the outer contour of the tread of the tire in Comparative Example 1 when the tire is inflated at a use internal pressure;
Fig. 11 is a front print of the tire in Comparative Example l;
Fig. 12 is a schematic view showing a maximum height SH from a bead base to a tread inside a mold; and Fig. 13 is a schematic sectional view showing a location where a tread is worn near a tread edge.
First, numerical limitations of the present invention will be explained below.
The reason why the boundary "m" between the tread portions having positive and negative radii of curvature, respectively, is set in range from 0.64x(TW/2) to 0.85x(TW/2) from the tread center "~" is as follows:
(1) If the above boundary between the tread portions having positive and negative radii of curvature, respectively, is located at less than 0.64x(TW/2) from the tread center, the diameter of the tread near the 1/4 point increases upon application of the internal pressure/ so that balance of the crown portion breaks and the ground contact length of the shoulder portion of the tread becomes shorter.
Consequently, edge drop wear is likely to occur.
~ 2) On the other hand, if the boundary between the tread portions having positive and negative radii of curvature, respectively, is located at more than 0.85x(TW/2) from the tread center, the radius of the curvature of the latter tread portion remains negative after the application of the internal pressure. Thus, the ground contact length of this tread portion becomes shorter to accelerate wearing there.
The reason why the absolute value of the negative radius of curvature is set in a range from 1 TW
to 30 TW is as follows:
(1) If the magnitude of the negative radius of curvature is less than 1 TW, it remains negative after the application of the internal pressure. Thus, the ground contact length thereof becomes shorter to accelerate wearing there.
(2) If the negative radius of curvature exceeds 30 TW, the diameter of the tread near the 1/4 point increase to break the balance of the crown shape.
Consequently, the ground contact length of the shoulder portion becomes shorter by the shortened amount so that edge drop wear is likely to occur.
In all examples given below, H3/H1 was set at 0.15. However, as discussed later, it is possible to set the tread shoulder edge drop correcting value H3 in a range from 0.05 to 0.40 of H1.
H1 is a vertical distance between a center "Q"
of a tread and an edge "O" of the tread which is formed at a ~ingle radius of curvature, "R1", as viewed in a tread ~ection inside a mold (see Fig. 1).
H3 is a vertical distance between the tread edge "O" and an edge, "P", of a tread which is formed at a negative radius of curvature, "R2", at a shoulder portion according to the present invention. That is, H3 is a tread shoulder edge drop-correcting value l3ls~ao indicating how much the edge "P" of the tread formed by the above positive radius of curvature is radially outwardly shifted by the negative radius of curvature, "R2," according to ~he present invention (see Fig. 1).
As mentioned above, the reason why the tread shoulder edge drop-correcting value H3 is set in a range from 0.05 to 0.40 of ~1 is as follows:
(1) If the tread shoulder edge drop-correcting value H3 is less than 0.05 Hl, the ground contact shape of the tread shoulder portion dc7 not largely differ from that of Comparative Example 1 (fc~rmed by a mold having a crown of a single radiu~ of curvature). Thus, an effect of the negative radius of curvature, "R2", upon the tread shoulder portion according to the present invention is reduoed.
(2) On the other hand, if the tread shoulder edge drop-correcting value ~3 is more than 0.40 Hl, the ground contact length o the foot print at the tread ground contact edge only becomes too great.
Conse~uently, since the length of the tread ground contact area axially inside the tread edge remains small, uneven wearing of the tread axially inside ~he tread ground contact edge is promoted.
, ~ r "
6 (3 0 Fig. 9. shows a schematic sectional view of a high internal pressure type heavy duty pneumatic radial tire (Comparative Example 1) having the outer contour of a tread formed at a single radius of curva-ture, R6, inside a mold, a~ in the case of heavy duty pneumatic radial tires to be used in trucks, buses, etc.
When such a tire was vulcanized inside the mold and actually run under application of a high internal pressure (9.8 kg/cm2) on a test course, its uneven wear resistance was not satisfactory. Then, a cause was investigated, and the following fact was revealed. That is, when a hiyh internal pressure (9.8 kg/cm2 or more) is applied to a tire after vulcaniza-tion, as shown in Fig. 10, an edge "y" of a tread of the actual tire is radially inwardly located by a ver-tical distance "S" from an edge "x" of a tread having an imaginary single radius of curvature (drawn by a dotted line), R7, expected at a shoulder of the tread.
In this way, it is seen that application of such a high internal pressure to the tire makes the outer contour of the tread shoulder portion to have an unexpected radius of curvature, Rg, which is smaller than the radius of curvature, R7, at the central portion of the tread.
Turning to a ground contact shape (foot print) of the tire to which load is applied, the fol-lowing fact has been made clear. That is, as shown in - lla -!~.
;~
13~ 960~
Fig. 11, edge corners of the ground contact area areround so that the ground contact length, "t", of the edge of the foot print is shorter. Consequently, the tread is dragged at the edges of the ground contact area, and thus the edges are worn at an early stage, which leads to uneven wearing such as shoulder drop wearing.
Further, it was analyzed that as shown in Fig. 9, when the tire in Comparative Example 1 is inflated at a high use internal pressure, the outer contour of the tread expands radially outwardly from that of the tread inside the mold. At that time, since the use internal pressure is very high, the center por-tion of the tread between almost 1/4 points, that is, points which are axially separated from a tread center by a distance equal to about 1/2 of a half of the width of the tread expands more radially outwardly than the tread shoulder portion. Consequently, the contour of the tread shoulder comes to have a second radius of curvature, Rg, due to the application of the internal pressure to cause a radial drop "S" of the tread edge.
Such a phenomenon is not seen in conventional heavy duty pneumatic radial tires of this type to be used for trucks, buses, etc. at low internal pressures.
(Examples) Figs. 1-5 show by way of example embodiments according to the present invention. Fig. 1 is - llb -1~ .
, . . .
131~600 a schematic sectional view illustrating an outer contour of a tire according to the present invention inside a mold. Fig. 2 is a schematic sectional view illustrating the outer contour of the tire according to the present invention which is inflated at a use internal pressure. Fig. 3 is a schematic sectional view showing that the entire outer contour of the tread of the tire according to the present invention radially outwardly expands from the tread outer contour inside the mold. Fig. 4 is a schematic sectional view illustrating outer contours of treads of the tires according to the present invention, and Comparative Examples l and 2 in a solid line, a dotted line, and a single dotted chain line, respectively. Fig. 5 is a foot print showing the shape of a ground contact area of the tread according to the present invention.
In the drawings, "E" denotes a high internal pressure type heavy duty pneumatic radial tire as an embodiment according to the present invention in which an outer contour of a center portion of a tread between the tread center "Q" and a point "m" separated from the tread center line CL by a distance equal to from 0.64 to 0.85 of a half of the tread width, (TW/2) inside a mold has a positive radius of curvature, Rl, having a center of the curvature on a side of an axis of the tire, while the outer contour of the tread shoulder portion axially outwardly located from the above point "m" inside the mold has a negative radius of curvature, R2, which is in a range from 1 to 30 of the tread width (TW) and which has a curvature center on the side opposite to the tire. ~ tread shoulder edge drop-correcting value H3 is in a range from 0.05 to 0.40 of a drop amount Hl in the case that a tread crown is formed at a single radius of curvature. When the tire is inflated at a use internal pressure, the entire outer contour of the tread expands radially outwardly from that of the tread inside the mold to make the outer contour of the tread at a single radius of curvature so that a ground contact shape of the tread under load becomes almost rectangular.
Now, explanation will be made in more detail.
In the specific examples, H3/Hl was all set at 0.15, but as mentioned later, it is possible to set H3/H
in a range from 0.05 to 0.40 Hl.
The tire size in the examples was TBRE 13.50/85 R 16, and a rim used was 9.00 V x 16.
The other dimensions are given in the following Table 1.
In Fig. 3, outer contours of the tread exhibited when the tire is assembled to a rim and inflated at an internal pressure of 0.5 kg/cm2 and a use internal pressure of 9.8 kg/cm2 are drawn by a solid line and a dotted line, respectively.
13~9~
Steel cords reinforcing a carcass (not shown) are arranged at 90 with respect to a tire circumferential direction. A belt B is constituted by steel cords. Cord angles of lower, intermediate and upper belt layers Bl, ~2, and B3 are 23 rightwardly inclined, 72 rightwardly inclined, and 72 leftwardly inclined with respect to the tire circumferential direction, respectively A main belt portion is constituted by intersecting belt cords of the intermediate belt layer B2 and those of the upper belt layer B3.
The shape of a buttress leading to a side wall of the tire from the tread edge influences an edge drop-wearing which is likely to occur near the tread edge.
As shown in Fig. 1, the buttress is formed from the tread edge "P" at a curvature having its center on a straight line passing through the tread edge and in parallel to the tire rotary axis or in a range X which falls within 5% of the sectional height SH (see Fig. 12) of the tire radially and axially outwardly from this straight line, and it is preferable to set the radius of the curvature, "r", in a range from 5% to 25% of the tread width (=2 x Ll).
Further, according to this tire, the radius of curvature, "r", of the buttress is set at 20 mm (about 9.3% of the tread width). As shown in Fig. 1, the center of the curvature of the buttress is located near the line passing through the tread edge "P" and in parallel with the tire rotary axis.
By designing the buttress like this, rigidity of the tread edge portion can be optimized and occurrence of edge drop wearing can be delayed.
(Comparative Examples) Comparative Examples have the same fundamental constituent features as in Examples other than the dimensions given in Table 1.
In Comparative Example 2, the sectional shape of the shoulder portion of the tread inside a mold was straight. As shown in Fig. 6, the shoulder portion was formed by a straight line continuing to the curve of the radius of curvature, Rl. Thus, the outer contour of the tread shoulder radially outwardly expands as compared with the tire in which the tread is formed at a single positive radius of curvature, Rl (the shoulder portion is depicted by a dotted line).
That is, the outer contour of the tread is formed by the straight line such that the tread edge may be located at "P" radially outside the edge "O" of the tread having the imaginary single positive radius of curvature R1.
The tangential point between the curve of the radius of curvature, Rl, and the straight line is 13196~0 located at L2=68 mm from the tread center. The tread shoulder edge drop-correcting value H3 is 1.1, and H3/H
is 0.15.
Fig. 7 shows the tire in Comparative Example 2 which was vulcanized in the mold and inflated at a use internal pressure of 9.8 kg/cm2. In the tire of Comparative Example 2, the outer contour of the tread is formed at radii of curvature, R4 and R5 (smaller than R4) at the center portion and the shoulder portion of the tread, respectively (the tread shoulder portion is depicted by a dotted line). Consequently, the tread edge "Y" drops radially inside the tire by "S" from an edge "X" of a tread which would be formed at an imaginary radius of curvature, R4.
As shown in Fig. 8, ground contact corners of a foot print of the tire in Comparative Example 2 are rounded 80 that edge drop wearing at an early stage cannot be restrained due to variation in the ground circumferential length of the edge portion of the ground contact area.
Test Method:
Tires were tested at an internal pressure of 9.8 kg/cm2 under a load of 4 ton/tire in the Bridgestone te~t course as mounted on a truck.
In Table 2, Tl and T2 denote edge drop wearing at a tread edge and wearing axially inside the tread edge, respectively.
Since the negative radius of curvature of the crown portion in Comparative Example 3 is too small and H3/Hl in Comparative Example 5 is too large, the outer contour of the tread when the tires were inflated at a use internal pressure remained at a reverse radius of curvature at the tread edges. Consequently, the circumferential ground contact length of the tread in the foot print at a zone near the tread edge becomes smaller so that T2 as a core of uneven wearing, which causes a portion of the tread having smaller ground contact length to be more worn, occurs at an early stage to deteriorate uneven wearing resistance (Fig. 13).
Fig. 8 shows a foot print of the tire in Comparative Example 2. Ground contact corners are rounded to make the circumferential ground contact length at the edge portions ununiform. Thus, edge drop wearing at the early stage cannot be prevented.
To the contrary, as shown in Fig. 5, the foot print of Examples according to the present invention exhibit a substantially rectangular shape to suppressed edge drop wearing.
In Table 2, with respect to each of Tl and T2, results are shown by index taking that of Example 1 as 100. The greater the index of each of Tl and T2, the more excellent the wearing resistance.
1319~00 i i i ~ _ 1 D, ~ ~ n = n R n ~ ~ o o u ~ ~ n s r~ s n ~n _l o o 11 o ~ n n n o R v~l ~ _i u a Cr=~= ~ O~ _ l ~D l = l ~n l ,1 R N ~ ~ _ o _ _ E~ R ~ L L ~ R N 11~ _I L O
K N o N o s o m _i o o n _ L ~ . ~` ~ ~
R ~ i r R R = .~ o ~ ~ ~ O,~ r C
~ ~ ~3 ~ _ ~ _ ~ ~ ~ ~ 3 3 ~ N N ~! ~ ~! ~ tl~ _ )~ ~2:
i~l96(~0 ~ ~ U~
U
, ~ ~ aJ
~ ~ o U~-a ~'V ~ CO o U~
~,,o o E V 13 ~ o U~W
~-=o ~ o o .0~ i~ cn _ _l o o ~ o ~o o ~
~ o ,ol Pq .~c ~ ~ -- ~a --tl- C ~ ~ S tl- tJ~ C
~ ~d'C ~ D. ~ '~
~ ~ 3 ~ o 1- c: JJ 3 c: 0 ~ O ~ ~ ~ ul o ~ n~
~ 3 1~ 3 13196~0 As mentioned above, the edge drop wearing (Tl) and wearing (T2) occurring axially inside the tread edge at the early stage as cores of uneven wearing can be suppressed as seen in Table 2. Thus, high internal pressure type heavy duty pneumatic radial tires having excellent wear resistance can be obtained.
As shown in Fig. 4, the present invention is to provide high internal pressure type heavy duty pneumatic radial tires having the tread of a single radius of curvature and more excellent wear resistance with a substantially rectangular foot print when being inflated at a high use internal pressure as compared with Comparative Examples.
HEAVY DUTY PNEUMATIC RADIAL TIRES
The present invention relates to high internal pressure type heavy duty pneumatic radial tires. More specifically, the invention relates to high internal pressure type heavy duty pneumatic radial tires which are to be served under higher internal pressures and higher loads as compared with conventional heavy duty pneumatic radial tires for use in trucks, buses, etc.
and which have improved shoulder edge drop wear resistance and uneven wear resistance.
Conventional heavy duty pneumatic radial tires used in trucks, buses, etc. are produced by shaping an outer contour of a tread inside a mold at a single radius of curvature as viewed in radial planes and effecting vulcanization there, and are run under application of a use internal pressure of about 7.25 kg/cm2. These tires have especially no problem in terms of uneven wear resistance.
However, if conventional heavy duty pneumatic radial tires of this type for use in trucks, buses, etc.
were employed under higher load, it was revealed that the tires had troubles in uneven wear resistance.
Under the circumstances, the present inventors 13196~0 have tried to develop heavy duty pneumatic radial tires to be used under loads higher than those in the case of conventional ones, and proceeded their studies with respect to the following two points:
(l) An air volume inside a tire is increased.
(2) A use internal pressure of a tire is increased.
As a result, they found that the above item (l) can be realized by making a diameter of a use rim smaller, while with respect to the item (2), a tire can be designed to withstand such a high use internal pressure of 9.0 to 12.0 kg/cm2.
When a high internal pressure type heavy duty pneumatic radial tire having the outer contour of a tread formed at a single radius of curvature, inside a mold, as in the case of heavy duty pneumatic radial tires to be used in trucks, buses, etc., was vulcanized inside the mold and actually run under application of a high internal pressure (9.8 kg/cm2) on a test course, its uneven wear resistance was not satisfactory. Then, a cause was investigated, and the following fact was revealed. That is, when a high internal pressure (9.8 kg/cm2 or more) is applied to a tire after vulcaniza-tion, an edge of a tread of the actual tire is radially inwardly located by a vertical distance from ,~' i3~9~
an edge of a tread having an imaginary single radius of curvature expected at a shoulder of the tread. In this way, it is seen that application of such a high inter-nal pressure to the tire makes the outer contour of the tread shoulder portion to have an unexpected radius of curvature which is smaller than the radius of curvature at the central portion of the tread.
Turning to a ground contact shape (foot print) of the tire to which load is applied, the fol-lowing fact has been made clear. That is, edge cornersof the ground contact area are round so that the ground contact length of the edge of the foot print is shorter. Consequently, the tread is dragged at the edges of the ground contact area, and thus the edges are worn at an early stage, which leads to uneven wear-ing such as shoulder drop wearing.
Further, it was analyzed that when the tire is inflated at a high use internal pressure, the outer contour of the tread expands radially outwardly from that of the tread inside the mold. At that time, since the use internal pressure is very high, the center por-tion of the tread between almost 1/4 points, that is, points which are axially separated from a tread center h;~
~ ~. . . ~ "
1319~00 by a distance equal to about 1/2 of a half of the width of the tread more expands radially outwardly than the tread shoulder portion. Consequently~ the contour of the tread shoulder comes to have a second radius o~
curvature due to the application of the internal pressure to cause a radial drop of the tread edge.
Such a phenomenon is not seen in conventional heavy duty pneumatic radial tires of this type to be used for trucks, buses, etc. at low internal pressures.
It is an object of the present invention to provide high internal pressure type heavy duty pneumatic radial tire~ which have uneven wear resistance such as shoulder drop wear re~istance greatly improved, when in use at an internal pressure 19.0 to 12.0 kg/cm2) higher than in the case of conventional heavy duty pneumatic tires ~or use in trucks and buses, by making a dropped amount of the outer ~ontour of the tread shoulder smaller than that o~ the tread shoulder having a single radius oE curvature and thus preventing the ground contact len~th of edges o~ the tread ~n contact with ground under load from becoming shorter.
In order to attain the above-mentioned object, according to the present invention, the outer contour of the tread at a central portion between points axially separated f rom the tread center by a distance ~alling in a range from 0.64 to 0.85 of a halE of the ,~,,;,,, width o~ the tread inside a mold has a posi-tive radius of curvature which has a curvature center o:l a side of an axis oE the tire, while the contour o~ the tread at each o~ the shoulder portions located axially outside the above points inside the mold have a negative radius oE curvature which possesses a curvature center on a side opposite to the tire axis while the negative radius of curvature has an absolute value in a range from 1 to 30 times the width of the tread. As a result, an amount for correcting a tread shoulder drop (hereinafter referred to as "tread shoulder edge drop-correcting amount") may be in a range ~rom 0.05 to 0.4 time an amount of a shoulder drop occurring in the case of a tire with a tread having a crown of a single radius of curvature inside a mold, whereby the entire outer contour of the tread expands radially outwardly from that o~ the tread inside the mold corresponding thereto through application of a use internal pre3sure to have a single radius of curvature.
~ ccording to the present invention, despite that the use internal pressure is high, the foot print is made almost rectangular by enlarging the ground contact length of the tread edges. Consequently, uneven wear resistance can be improved to a large extent.
These and other objects, features, and advantages of the present invention will be appreciated upon reading of the following description of the invention when taken in conjunction with the attached drawings, with the understanding that some modiflca-tions, variations, and changes of the same could be made by a person having an ordinary knowledge of the art to which the invention pertains, without departing from the spirit of the invention or the scope of claims appended hereto.
For a better understanding of the invention, reference is made to the attached drawings, wherein:
Fig. 1 is a schematic sectional view illustrating an outer contour of a tread of a tire according to the present invention inside a mold;
Fig. 2 is a schematic sectional view of the outer contour of the tread of the tire according to the present invention when being inflated at a use internal pressure;
Fig. 3 is a schematic view showing that the entire outer contour of the tread of the tire according to the present invention expands radially outwardly from that of the tread inside the mold when the tire is inflated at a use internal pressure;
Fig. 4 is a schematic sectional view in which outer contours of treads of tires in the present invention, and Comparative Examples 1 and 2 are shown by a solid line, a dotted line, and a one dot-chain line, 13196~0 respectively, under application of a use internal pressure;
Fig. S is a foot print showing a ground contact shape of the tread of the tire according to the present invention;
Fig. 6 is a schematic sectional view illustrating an outer contour of a tread of a tire in Comparative Example 2 inside a mold;
Fig. 7 is a schematic sectional view illustrat-ing the outer contour of the tread of the tire in Comparative Example 2 when the tire being inflated at a use internal pressure;
Fig. 8 is a foot print of the tire in Comparative Example 2;
Fig. 9 is a schematic sectional view illustrat-ing the outer contour of a tread of a tire in Comparative Example 1 inside a mold;
Fig. 10 ia a schematic sectional view of the outer contour of the tread of the tire in Comparative Example 1 when the tire is inflated at a use internal pressure;
Fig. 11 is a front print of the tire in Comparative Example l;
Fig. 12 is a schematic view showing a maximum height SH from a bead base to a tread inside a mold; and Fig. 13 is a schematic sectional view showing a location where a tread is worn near a tread edge.
First, numerical limitations of the present invention will be explained below.
The reason why the boundary "m" between the tread portions having positive and negative radii of curvature, respectively, is set in range from 0.64x(TW/2) to 0.85x(TW/2) from the tread center "~" is as follows:
(1) If the above boundary between the tread portions having positive and negative radii of curvature, respectively, is located at less than 0.64x(TW/2) from the tread center, the diameter of the tread near the 1/4 point increases upon application of the internal pressure/ so that balance of the crown portion breaks and the ground contact length of the shoulder portion of the tread becomes shorter.
Consequently, edge drop wear is likely to occur.
~ 2) On the other hand, if the boundary between the tread portions having positive and negative radii of curvature, respectively, is located at more than 0.85x(TW/2) from the tread center, the radius of the curvature of the latter tread portion remains negative after the application of the internal pressure. Thus, the ground contact length of this tread portion becomes shorter to accelerate wearing there.
The reason why the absolute value of the negative radius of curvature is set in a range from 1 TW
to 30 TW is as follows:
(1) If the magnitude of the negative radius of curvature is less than 1 TW, it remains negative after the application of the internal pressure. Thus, the ground contact length thereof becomes shorter to accelerate wearing there.
(2) If the negative radius of curvature exceeds 30 TW, the diameter of the tread near the 1/4 point increase to break the balance of the crown shape.
Consequently, the ground contact length of the shoulder portion becomes shorter by the shortened amount so that edge drop wear is likely to occur.
In all examples given below, H3/H1 was set at 0.15. However, as discussed later, it is possible to set the tread shoulder edge drop correcting value H3 in a range from 0.05 to 0.40 of H1.
H1 is a vertical distance between a center "Q"
of a tread and an edge "O" of the tread which is formed at a ~ingle radius of curvature, "R1", as viewed in a tread ~ection inside a mold (see Fig. 1).
H3 is a vertical distance between the tread edge "O" and an edge, "P", of a tread which is formed at a negative radius of curvature, "R2", at a shoulder portion according to the present invention. That is, H3 is a tread shoulder edge drop-correcting value l3ls~ao indicating how much the edge "P" of the tread formed by the above positive radius of curvature is radially outwardly shifted by the negative radius of curvature, "R2," according to ~he present invention (see Fig. 1).
As mentioned above, the reason why the tread shoulder edge drop-correcting value H3 is set in a range from 0.05 to 0.40 of ~1 is as follows:
(1) If the tread shoulder edge drop-correcting value H3 is less than 0.05 Hl, the ground contact shape of the tread shoulder portion dc7 not largely differ from that of Comparative Example 1 (fc~rmed by a mold having a crown of a single radiu~ of curvature). Thus, an effect of the negative radius of curvature, "R2", upon the tread shoulder portion according to the present invention is reduoed.
(2) On the other hand, if the tread shoulder edge drop-correcting value ~3 is more than 0.40 Hl, the ground contact length o the foot print at the tread ground contact edge only becomes too great.
Conse~uently, since the length of the tread ground contact area axially inside the tread edge remains small, uneven wearing of the tread axially inside ~he tread ground contact edge is promoted.
, ~ r "
6 (3 0 Fig. 9. shows a schematic sectional view of a high internal pressure type heavy duty pneumatic radial tire (Comparative Example 1) having the outer contour of a tread formed at a single radius of curva-ture, R6, inside a mold, a~ in the case of heavy duty pneumatic radial tires to be used in trucks, buses, etc.
When such a tire was vulcanized inside the mold and actually run under application of a high internal pressure (9.8 kg/cm2) on a test course, its uneven wear resistance was not satisfactory. Then, a cause was investigated, and the following fact was revealed. That is, when a hiyh internal pressure (9.8 kg/cm2 or more) is applied to a tire after vulcaniza-tion, as shown in Fig. 10, an edge "y" of a tread of the actual tire is radially inwardly located by a ver-tical distance "S" from an edge "x" of a tread having an imaginary single radius of curvature (drawn by a dotted line), R7, expected at a shoulder of the tread.
In this way, it is seen that application of such a high internal pressure to the tire makes the outer contour of the tread shoulder portion to have an unexpected radius of curvature, Rg, which is smaller than the radius of curvature, R7, at the central portion of the tread.
Turning to a ground contact shape (foot print) of the tire to which load is applied, the fol-lowing fact has been made clear. That is, as shown in - lla -!~.
;~
13~ 960~
Fig. 11, edge corners of the ground contact area areround so that the ground contact length, "t", of the edge of the foot print is shorter. Consequently, the tread is dragged at the edges of the ground contact area, and thus the edges are worn at an early stage, which leads to uneven wearing such as shoulder drop wearing.
Further, it was analyzed that as shown in Fig. 9, when the tire in Comparative Example 1 is inflated at a high use internal pressure, the outer contour of the tread expands radially outwardly from that of the tread inside the mold. At that time, since the use internal pressure is very high, the center por-tion of the tread between almost 1/4 points, that is, points which are axially separated from a tread center by a distance equal to about 1/2 of a half of the width of the tread expands more radially outwardly than the tread shoulder portion. Consequently, the contour of the tread shoulder comes to have a second radius of curvature, Rg, due to the application of the internal pressure to cause a radial drop "S" of the tread edge.
Such a phenomenon is not seen in conventional heavy duty pneumatic radial tires of this type to be used for trucks, buses, etc. at low internal pressures.
(Examples) Figs. 1-5 show by way of example embodiments according to the present invention. Fig. 1 is - llb -1~ .
, . . .
131~600 a schematic sectional view illustrating an outer contour of a tire according to the present invention inside a mold. Fig. 2 is a schematic sectional view illustrating the outer contour of the tire according to the present invention which is inflated at a use internal pressure. Fig. 3 is a schematic sectional view showing that the entire outer contour of the tread of the tire according to the present invention radially outwardly expands from the tread outer contour inside the mold. Fig. 4 is a schematic sectional view illustrating outer contours of treads of the tires according to the present invention, and Comparative Examples l and 2 in a solid line, a dotted line, and a single dotted chain line, respectively. Fig. 5 is a foot print showing the shape of a ground contact area of the tread according to the present invention.
In the drawings, "E" denotes a high internal pressure type heavy duty pneumatic radial tire as an embodiment according to the present invention in which an outer contour of a center portion of a tread between the tread center "Q" and a point "m" separated from the tread center line CL by a distance equal to from 0.64 to 0.85 of a half of the tread width, (TW/2) inside a mold has a positive radius of curvature, Rl, having a center of the curvature on a side of an axis of the tire, while the outer contour of the tread shoulder portion axially outwardly located from the above point "m" inside the mold has a negative radius of curvature, R2, which is in a range from 1 to 30 of the tread width (TW) and which has a curvature center on the side opposite to the tire. ~ tread shoulder edge drop-correcting value H3 is in a range from 0.05 to 0.40 of a drop amount Hl in the case that a tread crown is formed at a single radius of curvature. When the tire is inflated at a use internal pressure, the entire outer contour of the tread expands radially outwardly from that of the tread inside the mold to make the outer contour of the tread at a single radius of curvature so that a ground contact shape of the tread under load becomes almost rectangular.
Now, explanation will be made in more detail.
In the specific examples, H3/Hl was all set at 0.15, but as mentioned later, it is possible to set H3/H
in a range from 0.05 to 0.40 Hl.
The tire size in the examples was TBRE 13.50/85 R 16, and a rim used was 9.00 V x 16.
The other dimensions are given in the following Table 1.
In Fig. 3, outer contours of the tread exhibited when the tire is assembled to a rim and inflated at an internal pressure of 0.5 kg/cm2 and a use internal pressure of 9.8 kg/cm2 are drawn by a solid line and a dotted line, respectively.
13~9~
Steel cords reinforcing a carcass (not shown) are arranged at 90 with respect to a tire circumferential direction. A belt B is constituted by steel cords. Cord angles of lower, intermediate and upper belt layers Bl, ~2, and B3 are 23 rightwardly inclined, 72 rightwardly inclined, and 72 leftwardly inclined with respect to the tire circumferential direction, respectively A main belt portion is constituted by intersecting belt cords of the intermediate belt layer B2 and those of the upper belt layer B3.
The shape of a buttress leading to a side wall of the tire from the tread edge influences an edge drop-wearing which is likely to occur near the tread edge.
As shown in Fig. 1, the buttress is formed from the tread edge "P" at a curvature having its center on a straight line passing through the tread edge and in parallel to the tire rotary axis or in a range X which falls within 5% of the sectional height SH (see Fig. 12) of the tire radially and axially outwardly from this straight line, and it is preferable to set the radius of the curvature, "r", in a range from 5% to 25% of the tread width (=2 x Ll).
Further, according to this tire, the radius of curvature, "r", of the buttress is set at 20 mm (about 9.3% of the tread width). As shown in Fig. 1, the center of the curvature of the buttress is located near the line passing through the tread edge "P" and in parallel with the tire rotary axis.
By designing the buttress like this, rigidity of the tread edge portion can be optimized and occurrence of edge drop wearing can be delayed.
(Comparative Examples) Comparative Examples have the same fundamental constituent features as in Examples other than the dimensions given in Table 1.
In Comparative Example 2, the sectional shape of the shoulder portion of the tread inside a mold was straight. As shown in Fig. 6, the shoulder portion was formed by a straight line continuing to the curve of the radius of curvature, Rl. Thus, the outer contour of the tread shoulder radially outwardly expands as compared with the tire in which the tread is formed at a single positive radius of curvature, Rl (the shoulder portion is depicted by a dotted line).
That is, the outer contour of the tread is formed by the straight line such that the tread edge may be located at "P" radially outside the edge "O" of the tread having the imaginary single positive radius of curvature R1.
The tangential point between the curve of the radius of curvature, Rl, and the straight line is 13196~0 located at L2=68 mm from the tread center. The tread shoulder edge drop-correcting value H3 is 1.1, and H3/H
is 0.15.
Fig. 7 shows the tire in Comparative Example 2 which was vulcanized in the mold and inflated at a use internal pressure of 9.8 kg/cm2. In the tire of Comparative Example 2, the outer contour of the tread is formed at radii of curvature, R4 and R5 (smaller than R4) at the center portion and the shoulder portion of the tread, respectively (the tread shoulder portion is depicted by a dotted line). Consequently, the tread edge "Y" drops radially inside the tire by "S" from an edge "X" of a tread which would be formed at an imaginary radius of curvature, R4.
As shown in Fig. 8, ground contact corners of a foot print of the tire in Comparative Example 2 are rounded 80 that edge drop wearing at an early stage cannot be restrained due to variation in the ground circumferential length of the edge portion of the ground contact area.
Test Method:
Tires were tested at an internal pressure of 9.8 kg/cm2 under a load of 4 ton/tire in the Bridgestone te~t course as mounted on a truck.
In Table 2, Tl and T2 denote edge drop wearing at a tread edge and wearing axially inside the tread edge, respectively.
Since the negative radius of curvature of the crown portion in Comparative Example 3 is too small and H3/Hl in Comparative Example 5 is too large, the outer contour of the tread when the tires were inflated at a use internal pressure remained at a reverse radius of curvature at the tread edges. Consequently, the circumferential ground contact length of the tread in the foot print at a zone near the tread edge becomes smaller so that T2 as a core of uneven wearing, which causes a portion of the tread having smaller ground contact length to be more worn, occurs at an early stage to deteriorate uneven wearing resistance (Fig. 13).
Fig. 8 shows a foot print of the tire in Comparative Example 2. Ground contact corners are rounded to make the circumferential ground contact length at the edge portions ununiform. Thus, edge drop wearing at the early stage cannot be prevented.
To the contrary, as shown in Fig. 5, the foot print of Examples according to the present invention exhibit a substantially rectangular shape to suppressed edge drop wearing.
In Table 2, with respect to each of Tl and T2, results are shown by index taking that of Example 1 as 100. The greater the index of each of Tl and T2, the more excellent the wearing resistance.
1319~00 i i i ~ _ 1 D, ~ ~ n = n R n ~ ~ o o u ~ ~ n s r~ s n ~n _l o o 11 o ~ n n n o R v~l ~ _i u a Cr=~= ~ O~ _ l ~D l = l ~n l ,1 R N ~ ~ _ o _ _ E~ R ~ L L ~ R N 11~ _I L O
K N o N o s o m _i o o n _ L ~ . ~` ~ ~
R ~ i r R R = .~ o ~ ~ ~ O,~ r C
~ ~ ~3 ~ _ ~ _ ~ ~ ~ ~ 3 3 ~ N N ~! ~ ~! ~ tl~ _ )~ ~2:
i~l96(~0 ~ ~ U~
U
, ~ ~ aJ
~ ~ o U~-a ~'V ~ CO o U~
~,,o o E V 13 ~ o U~W
~-=o ~ o o .0~ i~ cn _ _l o o ~ o ~o o ~
~ o ,ol Pq .~c ~ ~ -- ~a --tl- C ~ ~ S tl- tJ~ C
~ ~d'C ~ D. ~ '~
~ ~ 3 ~ o 1- c: JJ 3 c: 0 ~ O ~ ~ ~ ul o ~ n~
~ 3 1~ 3 13196~0 As mentioned above, the edge drop wearing (Tl) and wearing (T2) occurring axially inside the tread edge at the early stage as cores of uneven wearing can be suppressed as seen in Table 2. Thus, high internal pressure type heavy duty pneumatic radial tires having excellent wear resistance can be obtained.
As shown in Fig. 4, the present invention is to provide high internal pressure type heavy duty pneumatic radial tires having the tread of a single radius of curvature and more excellent wear resistance with a substantially rectangular foot print when being inflated at a high use internal pressure as compared with Comparative Examples.
Claims (4)
1. A high internal pressure type heavy duty pneumatic radial tire comprising a tread, said tire being formed and vulcanized in a mold, said tread having an outer contour inside the mold, said outer contour sectionally consisting of a curve having a positive radius of curvature with a curvature center on a side of a tire axis at a central portion of the tread extending between points ("m") being oppositely separated from a tread center by 0.64 to 0.85 of a half of a width of the tread (TW/2) and a curve having a negative radius of ourvature with a curvature center on a side opposite to the tire axis at tread shoulder portions axially outside said points ("m"), said negative radius of curvature having an absolute value of 1 to 30 of the tread width (TW), wherein a tread shoulder edge drop-correcting value (H3) is in a range from 0.05 to 0.40 of (H1) which is a radially dropped amount of an edge of the tread which would be formed in a mold sectionally having a single radius of curvature and the entire outer contour of the tread radially outwardly expands from that of the tread inside the mold by applying a use internal pressure to the tire to form the outer contour of the tread at a single radius of curvature.
2. A high internal pressure type heavy duty pneumatic radial tire according to claim 1, wherein a ground contact area of the tread under application of load exhibits a substantially rectangular shape.
3. A high internal pressure heavy duty pneumatic radial tire according to claim 1, wherein buttress portions each extending from the tread edge sectionally are formed at a curvature having a center falling in a straight line passing through the tread edge and in parallel to the tire rotary axis or in a range which falls within 5% of the sectional height of the tire radially and axially outwardly from the straight line, and a radius of the curvature is in a range from 5 to 20% of the tread width.
4. A high internal pressure heavy duty radial tire according to claim 3, wherein the radius of curvature of the buttress portions is about 9.3% of the tread width, and the center of the curvature is located near the straight line passing through the tread edge and in parallel with the tire rotary axis.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62-155397A JPH011608A (en) | 1987-06-24 | Pneumatic radial tires for high internal pressure and high loads | |
| JP155,397/87 | 1987-06-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1319600C true CA1319600C (en) | 1993-06-29 |
Family
ID=15605068
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000569783A Expired - Fee Related CA1319600C (en) | 1987-06-24 | 1988-06-17 | High internal pressure type heavy duty pneumatic radial tires |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA1319600C (en) |
| FR (1) | FR2617096B1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112277531A (en) * | 2019-07-22 | 2021-01-29 | 住友橡胶工业株式会社 | Heavy load pneumatic tire |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5616195A (en) * | 1995-08-28 | 1997-04-01 | The Goodyear Tire & Rubber Company | Low aspect ratio truck tire |
| JP3254166B2 (en) * | 1997-05-16 | 2002-02-04 | 住友ゴム工業株式会社 | Radial tires for heavy loads |
| DE102018206913A1 (en) * | 2018-05-04 | 2019-11-07 | Continental Reifen Deutschland Gmbh | Vehicle tires |
| WO2020141012A1 (en) * | 2018-12-31 | 2020-07-09 | Goldhofer Ag | Heavy-load vehicle |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT1034352B (en) * | 1975-03-18 | 1979-09-10 | Pirelli | PNEUMATIC WITH COMBINED PNEUMATIC AND STRUCTURAL LOAD |
| US4142930A (en) * | 1975-05-08 | 1979-03-06 | The Goodyear Tire & Rubber Company | Method of fabricating large tires |
| FR2499474A1 (en) * | 1981-02-12 | 1982-08-13 | Michelin & Cie | TIRE, IN PARTICULAR FOR AIRCRAFT, WITH TEXTILE CABLES TOP FRAME, AND METHOD FOR MANUFACTURING THE SAME |
-
1988
- 1988-06-17 CA CA000569783A patent/CA1319600C/en not_active Expired - Fee Related
- 1988-06-20 FR FR888808241A patent/FR2617096B1/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112277531A (en) * | 2019-07-22 | 2021-01-29 | 住友橡胶工业株式会社 | Heavy load pneumatic tire |
| US11390120B2 (en) * | 2019-07-22 | 2022-07-19 | Sumitomo Rubber Industries, Ltd. | Heavy duty pneumatic tire |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS641608A (en) | 1989-01-06 |
| FR2617096B1 (en) | 1992-11-27 |
| FR2617096A1 (en) | 1988-12-30 |
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