CA2000945A1 - Heavy duty pneumatic radial tires used under high internal pressure - Google Patents
Heavy duty pneumatic radial tires used under high internal pressureInfo
- Publication number
- CA2000945A1 CA2000945A1 CA 2000945 CA2000945A CA2000945A1 CA 2000945 A1 CA2000945 A1 CA 2000945A1 CA 2000945 CA2000945 CA 2000945 CA 2000945 A CA2000945 A CA 2000945A CA 2000945 A1 CA2000945 A1 CA 2000945A1
- Authority
- CA
- Canada
- Prior art keywords
- tire
- belt
- steel cord
- layer
- width
- 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.)
- Abandoned
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
- B60C11/03—Tread patterns
- B60C11/12—Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes
-
- 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
- B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
- B60C9/18—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers
- B60C9/20—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel
-
- 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
- B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
- B60C9/18—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers
- B60C9/28—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers characterised by the belt or breaker dimensions or curvature relative to carcass
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Tires In General (AREA)
Abstract
HEAVY DUTY PNEUMATIC RADIAL TIRES
USED UNDER HIGH INTERNAL PRESSURE
Abstract of the Disclosure A heavy duty pneumatic radial tire used under high internal pressure suitable for use in electric trains, subway trains and the like comprises a tread divided into plural ribs by circumferential main grooves, wherein plural sipes are formed in at least shoulder ribs and at least an end portion of each of the sipes located in the vicinity of a side edge of an outermost belt layer is extended at the same side as in an extending direction of cords of the outermost belt layer with respect to the equatorial plane of the tire.
USED UNDER HIGH INTERNAL PRESSURE
Abstract of the Disclosure A heavy duty pneumatic radial tire used under high internal pressure suitable for use in electric trains, subway trains and the like comprises a tread divided into plural ribs by circumferential main grooves, wherein plural sipes are formed in at least shoulder ribs and at least an end portion of each of the sipes located in the vicinity of a side edge of an outermost belt layer is extended at the same side as in an extending direction of cords of the outermost belt layer with respect to the equatorial plane of the tire.
Description
9f~
63-266,226 com~.
HEAVY DUTY PNEUMATIC RADIAL TIRES
USED UNDER HIGH INTERNAL PRESSURE
This invention relates to heavy duty pneumatic radial tires used under high internal pressure of 9-12 kgf/cm2, and more particularly to a heavy duty pneumatic radial tire used under high internal pressure 05 capable of very effectively preventing the occurrence of a so-called sipe tear when it is applied for electric trains, subway trains, monorailway trains, new transport systems or other vehicles.
As this type of the tire, there have hitherto been tires as shown in Fig. l, wherein an upper half portion of Fig. 1 indicates a part of a tread pattern and a lower half portion thereof indicates a part of tire section in widthwise direction.
In the lower half portion of Fig. l, numeral 51 is a carcass comprised of at l~ast one carcass ply, and numeral 52 is a belt superimposed about a crown portion of the carcass 51.
The belt 52 is comprised of three belt layers 53, 54 and 55 each containing cords such as steel cords therein. The steel cords of each of the belt layers extend in a direction crossing with an equatorial plane X-X of the tire as shown in the upper half portion of Fig. l.
63-266,226 com~.
HEAVY DUTY PNEUMATIC RADIAL TIRES
USED UNDER HIGH INTERNAL PRESSURE
This invention relates to heavy duty pneumatic radial tires used under high internal pressure of 9-12 kgf/cm2, and more particularly to a heavy duty pneumatic radial tire used under high internal pressure 05 capable of very effectively preventing the occurrence of a so-called sipe tear when it is applied for electric trains, subway trains, monorailway trains, new transport systems or other vehicles.
As this type of the tire, there have hitherto been tires as shown in Fig. l, wherein an upper half portion of Fig. 1 indicates a part of a tread pattern and a lower half portion thereof indicates a part of tire section in widthwise direction.
In the lower half portion of Fig. l, numeral 51 is a carcass comprised of at l~ast one carcass ply, and numeral 52 is a belt superimposed about a crown portion of the carcass 51.
The belt 52 is comprised of three belt layers 53, 54 and 55 each containing cords such as steel cords therein. The steel cords of each of the belt layers extend in a direction crossing with an equatorial plane X-X of the tire as shown in the upper half portion of Fig. l.
2~3B94~
Furthermore, numeral 56 is a tread portion.
This tread portion 56 is provided with five ribs 58 and 59 defined by four circumferential main grooves 57 extending zigza~ in the circumEerential direction.
05 Moreover, each of shoulder ribs 58 located at the shoulder portions of the tire is provided with plural sipes 60 arranged at substantially an equal interval in the circumferential direction of the tire.
In this case, each sipe 60 is a so-called blind sipe, both ends of which being terminated in the shoulder ribO Further r the central portion of the sipe 60 in the widthwise direction of the tire extends in the same direction as in the extending direction of cords 53a of the outermost belt layer 53 with respect to the equatorial plane X-X of the tire.
When the tire of this type is usually used under a high internal pressure of 9-12 kgf/cm2, the sipe 60 tends to enlarge in the widthwise direction.
In addition, the cords 53a of the outermost belt layer 53 is subjected to a lar~e tensile force at the stepping-in state, a compressive force at the ground contacting state and a tensile force at the kicking-out state during the rotating of the tire under loading.
Consequently, when fold end portions 60a and 60b extendin~ from the central portion of the sipe 60 are opposite to the extending direction of the cord 53a of 2~ 9'~
the outermost belt layer 53 with respect to the equatorial plane X-X of the tire as shown in Fig. l, an outer end portion of the sipe 60 in widthwise direction of the tire having a largest deformation amount is 05 particularly deformed in a direction of more enlarging the width of the sipe every the action of tensile force to the cord 53a, so that there is caused a problem that cracking toward the surface of the shoulder rib due to stress concentration or a so-called sipe tear is caused from the outer end position of the sipe 60 in the widthwise direction of the tire.
Moreover, if the sipe 60 is opened to the side end face of the tread portion 56, there is a problem of causing another kind of sipe tear from the sipe bottom at the opened end of the sipe 60 toward the sidewall.
Further, in order to sufficiently enhance the rigidity of the tread portion 56 for the improvement of wear resistance and traction performances in the conventional tire, the belt 52 is comprised of three steel cord layers 53, 54 and 55 each being continuously embedded from one side end to the other side end in the widthwise direction of the tire. Therefore, when the vehicle provided with such tires is steered through the action of a guide wheel contacting with a side wall of a track t guide plate or the like, an unnecessary and large cornering force is created in the tire rotating under loading to apply a large input from tne road surface to the ground contacting surface of the tire, whereby the ground contacting surface of the tire is apt to be subjected to an uneven wear at the side end portion of 05 the tread due to the dragging. Consequently, there may be a problem that such an uneven wear prematurely progresses toward the center of the tread portion in the widthwise direction.
Moreover, in such conventional tires, the thickness of rubber between adjoining belt layers 53 and 54, the cords of which layers being extended in an opposite direction with each other with respect to the equatorial plane of the tire is generally made relatively thin and uniform over a full width of the belt layer. When the tire is deformed during the rotation under loading, rubber located at the side end portions of the belt layers 53, 54 and in the vicinity thereof is subjected to a large shearing deformation based on the difference of the deformation behavior between the adjoining belt layers 53 and 54, and is apt to be damaged through the pecking with cord ends of the side end portions of the belt. As a result, there may be a highly fear that the occurrence of cracking at the damaged rubber and hence separation between belt layers 26 and other serious troubles are generated at a relatively premature period.
4~
It is, therefore, an object of the invention to solve the aforementioned problems of the conventional tires and provide a heav~v duty pneumatic radial tire used under high internal pressure capable of effectively 06 preventing the occurrence of sipe tear.
It is another object of the invention to provide a heavy duty pneumatic radial tire used under high internal pressure which can advantageously restrain the occurrence of uneven wear by sufficiently reducing the cornering force and can effectively prevent the occurrence of sipe tear and the growth of edge wear at the side end portion of the tread inward the widthwise direction of the tire, which has not completely avoided in the conventional tire.
It is the other object of the invention to provide a heavy duty pneumatic radial tire used under high internal pressure which can further delay the occurrence time of cracking in rubber at side end portions of the belt layer and the vicinity thereof.
According to the invention, there is the provision of a heavy duty pneumatic radial tire used under high internal pressure comprising a carcass composed of at least one carcass ply, a belt composed of plural belt layers, cords of which layers being extended 2~ in a direction crossing with an equatorial plane of the tire, a tread portion and plural sipes arranged in each shoulder of the tread portion at a given interval in the circumferential direction of the tire, characterized in that at least an end portion of each of said sipes located in the vicinity of a side edge of an outermost o~ belt layer is extended at the same side as in an extending direction of cords of said outermost belt layer with respect to the equatorial plane of the tire.
In a preferred embodiment of the invention, the belt is comprised of three steel cord layers, wherein an innermost steel cord layer of the belt has a split structure that a central portion of this steel cord layer is removed in the widthwise direction of the tire7 and a middle steel cord layer is made wider than innermost and outermost steel cord layers, and a width of the middle steel cord layer is 80-110% of a tread width and a width of each of the innermost steel cord layer and outermost steel cord layer is within a range of 80-98% of the width of the middle steel cord layer provided that a width of the removed portion of the innermost steel cord layer is within a range of 15-50%
of the width of the middle steel cord layer.
In another preferred embodiment of the invention, when the belt is comprised of three steel cord layers as mentioned above, a fine groove is further arranged in the tread portion toward the circumferential direction so as to extend outward from a side edge of 2~139~
the outermost steel cord layer within a range of not more than 15 mm in the widthwise direction of the tire.
In the other preferred embodiment of the invention, a thickness of rubber between the adjoining o~ belt layers, cords of which layers being crossed with each other with respect to the equatorial plane of the tire, is made 2-5 times at an outward end portion of the belt layer thicker than that at a central portion of the belt layer in widthwise direction of the tire.
The invention will be described with reference to the accompanying drawings, wherein:
Fig. 1 is a schematic view of the conventional xadial tire;
Fig. 2 is a schematic view of a first embodiment of the radial tire according to the invention;
Fig. 3 is a schematic view of a second embodi-ment of the radial tire according to the invention;
Fig. 4 is a schematic view of a third embodiment of the radial tire according to the invention;
Fiy. 5 is a schematic view of a fourth embodi-ment of the radial tire according to the invention; and Fig. 6 is a schematically sectional view of a fifth embodiment of the radial tire according to the invention.
In the heavy duty pneumatic radial tire used under high internal pressure according to the invention, ~o~9~
plural sipes are arranged in each of the shoulder ribs at a given interval toward the circumferential direction of the tire, wherein at least an end portion of each of the sipes in the shoulder located in the vicinity of the 05 side end of the outermost belt layer is extended at the same side as in the extending direction of cords of the outermost belt layer with respect to the equatorial plane of the tire. Thus, since the extending direction of the end portion of the sipe is same as in the cord direction of the outermost belt layer with respect to the equatorial plane, when a force in tensile direction is applied to the cords of the belt, the end portion of the sipe is subjected to a deformation in a direction reducing the sipe width, whereby the concentration of stress at the end of the sipe can effectively be mitigated to sufficiently prevent the occurrence of sipe tear from the end of the sipe. This is true whatever the outer end of the sipe is terminated in the shoulder rib or opened to the side end face of the tread portion.
Moreover, the extending direction of the end portion of the sipe means to include both a direction of zero degree with respect to the equatorial plane of the tire and a direction of zero degree with respect to the meridional plane of the tire. In fact, even when the 26 end portion of the sipe is existent at an angle of zero degree with respect to the equatorial plane or with 9~
respect to the meridional plane, the occurrence of sipe tear can effectively be prevented as compared with the conventional technique that the extending direction of the end portion of the sipe is opposite to the cord 05 direction of the outermost belt layer with respect to the equatorial plane.
When the belt is comprised of three steel cord layers, the innermost steel cord layer acting to control the growth of the tire in radial direction has a split structure, so that the function of the belt itself can sufficiently be developed and the cornering force can advantageously be reduced without degrading the rigidity at the side end portion of the tread and the durability of the belt, whereby the occurrence of uneven wear resulted from the application of large input from the road surface to the ground contacting portion of the tire can effectively be prevented. If the belt layer other than the innermost steel cord layer has a split structure, it is impossible to obtain a uniform crown shape during the inflation of the tire under a given internal pressure.
The reason why the width of the middle steel cord layer is made wider than those of the other steel cord layers and is within a range of 80-110% of the 2~ tread width is based on the fact that the region up to the side end portion of the tread is sufficiently 2~
reinforced to advantageously improve the wear resistance of the side end portion and also the increase of the end portion of the middle steel cord layer in radial direction is effectively suppressed. Further, the 05 reason why the width of each of the innermost and outermost steel cord layers is within a range of 80-98 of the width of the middle steel cord layer is due to the fact that when the width is less than 80%, the rigidity of the side end portion of the tread and the belt durability can not sufficiently be increased, while when it exceeds 98%, the premature occurrence of cracking in rubber from the end of the belt layer is caused and the growth of crack becomes fast.
Moreover, the reason why the width of the removed portion in the innermost steel cord layer is within a range of 15-50% of the width of the middle steel cord layer is due to the fact that when the width is less than 15~, the effective reduction of cornering force can not be achieved, while when it exceeds 50%, the rigidity at both side end portions of the tread in widthwise direction becomes too low.
Furthermore r when the fine groove extending in the circumferential direction of the tire is arranged in each side end portion of the tread, the progress of edge wear generated at the side end portion of the tread inward in the widthwise direction of the tire can z~
effectively be prevented. For example, when the ~ine groove is arranged in each of the shoulder ribs defined by main circumferential grooves, a portion of the shoulder rib located outward from the fine groove in the o~ widthwise direction of the tire opposes to the input of side force to cause an edge wear~ while a portion of the shoulder rib located inward from the fine groove in the widthwise direction of the tire is small in the bearing the input of side force and the progress of the above edge wear thereinto is prevented by the fine groove, so that the uniform wear state is exhibited without causing the edge wear.
On the other hand, the reason why the position of the fine groove arranged in the tread portion is 15 mm from the side edge of the outermost belt layer in the widthwise direction of the tire is due to the fact that when the fine groove is located over 15 mm outward in the widthwise direction of the tirel the input of side force to the edge of the rib portion located inside the fine groove in the widthwise direction of the tire increases, while when the fine groove is located over 15 mm inward in the widthwise direction of the tire, the width of edge wear at the rib portion located outside the fine groove in the widthwise direction of the tire is wider, Further, in order to prevent the occurrence of ~t~
cracking from the bottom of the fine groove toward the side edge of the belt layer, it is favorable to locate the fine groove inward from the side edge of the belt layer in the widthwise direction of the tire.
OS Preferably, when the width of the fine groove is not more than 2 mm at an inflation state under an internal pressure, the opposed groove walls of the fine groove are contacted with each other during the running of the tire under loading to prevent the occurrence of river wear from the both edge portions of the fine groove. In addition, when the depth of the fine groove is within a range of 50-110% of the depth of the circumferential main groove and is, for example, within a range of 5-30 mm, the progress of edge wear inward in the widthwise direction of the tire is sufficiently prevented and also the occurrence of cracking from the bottom of the fine groove is sufficiently prevented.
Moreover, when the thickness of rubber between the adjoining belt layers crossing cords with each other with respect to the equatorial plane is made 2-5 times at the outward end portion of the belt layer in widthwise direction thereof thicker than that at the central portion of the belt layer in widthwise direction thereof, strain quantity of rubber located at the outward end portion of the belt layer or its vicinity and showing a largest shearing strain to the belt layer ~o~
can be considerably reduced as compared with the conventional techni~ue when the tire is inflated and rotated under a load. Consequently, the quantity of rubber pecked by the cord ends at the side edge of the 05 belt layer is sufficiently reduced and the occurrence time of cracking in rubber can largely be delayed.
The reason why the thickness of rubber between the adjoining belt layers is made 2-5 times at the outward end portion of the belt layer thicker than that at the central portion of the belt layer in widthwise direction of the tire is due to the fact that when the thickness is less than 2 times, the occurrence of cracking in rubber at the belt end portion and its vicinity can not be delayed, while when it exceeds 1~ 5 times, the occurrence of cracking can not effectively be delayed but also thermal breakage of rubber is caused due to heat accumulated in rubber.
Accordlng to the invention, it is preferable that 100% tensile modulus of rubber located inside the belt layer and between the belt layers is 50-90 kg/cm2.
In this case, the shearing strain of rubber between the adjoining belt layers can be more reduced to delay the occurrence of cracking in rubber, and also the increase of circumferential length of the tire can advantageously be reduced in the inflation of the tire. When the 100%
tensile modulus is less than 50 kg/cm2, the shearing 2~
strain becomes too large, while when it exceeds 90 kg/cm2, the rigidity of rubber becomes too high to degrade the crack resistance of rubber.
Moreover, it is favorable that the angle of o~ cords in the belt layers extending in opposite directions to each other is within a range of 10-30 with respect to the equatorial plane of the tire. Thus, the increase of circumferential length of the tire can sufficiently be suppressed in the inflation of the tire and during the rotation under a load.
When the cord angle with respect to the equatorial plane of the tire is less than 10, the shearing strain at widthwise cord end portion of the belt layers crossing in opposite directions to each other increases to cause premature occurrence of cracking in rubber at the widthwise end portion of the belt layer, while when it exceeds 30, the growth of the belt layer in radial direction becomes large in the inflation under high internal pressure and also the shearing strain at widthwise end portion of the crossed belt layers increases to cause premature occurrence of cracking in rubber at the widthwise end portion of the belt layer.
In Fig. 2 is shown a first embodiment of the heavy duty pneumatic radial tire according to the invention, wherein numeral 1 is a carcass, numeral 2 a 2~ t~
belt superimposed about a crown portion of the carcass l, and numeral 3 a tread portion forming a ground contacting portion of the tire.
The carcass l is comprised of at least one 05 carcass ply containing cords arranged substantially in the radial direction of the tire, while the belt 2 is comprised of plural belt layers, cords of which layers crossing with each other with respect to the equatorial plane X-X of the tire. In this embodiment, the belt 2 is comprised of three belt layers 4, 5 and 6.
In the tread portion 3, five ribs 8 and 9 extending in the circumferential direction of the tire are defined by four circumferential main grooves 7.
At least shoulder ribs 8 among these ribs (only shoulder ribs in this embodiment) are provided with plural sipes lO located at substantially an equal interval in the circumferential direction of the tire.
As seen from the upper half portion of Fig. 2, each of these sipes lO is a blind sipe, both ends of which being terminated in the shoulder rib. Further, each sipe lO is extended at the same side as in the extending direction of cords ll of the outermost belt 1.ayer 4 with respect to the equatorial plane X-X of the tire over the full length of the sipe. Thus, the outer end portion of the sipe lO in the widthwise direction of the tire being largest in the deformation amount, or the end portion located in the vicinity of the side edge of the outermost belt layer 4 in the widthwise direction of the tire also directs at the same side as in the direction of the cord ll of the outermost belt layer 4.
05 The feature that the direction of the sipe 10 is the same side as in the extending direction of the cords of the outermost belt layer 4 with respect to the e~uatorial plane X-X means that the sipe lO is extended in the same quadrant as in the cords 11 when orthogonal coordinates are defined by a line segment parallel to the equatorial plane X-X and the meridional plane of the tire at proper position on the sipe and proper position on the cord. In this case, the extending direction of the sipe lG may be coincident with the co-ordinate axis.
In the illustrated embodiment, either end of the sipe lO may be opened to the groove wall of the circumferential main groove 7 or the side end face of the tread portion 3 alternately or entirely.
According to the tire of the illustrated embodiment r even when the large tensile force is applied to the cords 11 of the outermost belt layer 4 at the stepping-in and kicking-out states during the rotation under loading, it brings about the deformation of reducing the sipe width at the outer end portion of the sipe 10 in widthwise direction of the tire being largest in the deformation amount, whereby the occurrence of 2~3~3~
cracking from the outer end of the sipe toward the surface of the shoulder rib is effectively prevented.
This is particularly effective when the extending direction of the sipe lO is coincident with the 05 extending direction of the cord ll in the aforementioned orthogonal coordinates.
Similarly, such a deformation behavior at the outer end portion of the sipe is caused when the one end of the sipe lO is opened to the side end face of the tread portion 3. That is, the tensile force acting to the cord ll does not enlarge the width of the sipe lO
but causes the deformation of reducing the sipe width, so that the occurrence of cracking toward the side end face of the tread portion is effectively prevented.
Thus, according to the illustrated tire, the sipe tear generated from the end of the sipe lO being largest in the deformation amount can be prevented effectively.
In Fig. 3 is shown a second embodiment of the heavy duty pneumatic radial tire according to the invention, which is a modified embodiment of Fig. 2.
That is, only the outer folded end portion of each of the sipes lO arranged in the shoulder rib 8, which is located in the vicinity of the side end of the outermost belt layer 4, is extended at the same side as in the extending direction of the cords ll of the outermost belt layer 4 with respect to the equatorial plane X-X as shown at the orthogonal coordinates in Fig. 3.
In the embodiment of Fig. 3, the portion of the sipe lO being largest in the deformation amount, or the 05 portion apt to generate the sipe tear directs at the same side as in the extending direction of the cord 11, so that such an end portion of the sipe deforms in the direction of reducing the sipe width likewise the case of Fig. 2, and consequently the occurrence of sipe tear from the end of the sipe is effectively prevented.
Moreover, this is similar when the sipe end is opened to the side end face of the tread portion.
When the sipe is largely folded as shown in Fig. 3, it is favorable that the radius of curvature of the folded portion in the sipe is made large as far as possible in order to prevent the occurrence of sipe tear from the folded point.
Even in the embodiment of Fig. 3, the occurrence of sipe tear can be prevented sufficiently.
In Fig. 4 is shown a third embodiment of the heavy duty pneumatic radial tire according to the invention, which is a modified embodiment of Fig. 2.
In this embodiment, the belt 2 is comprised of three steel cord layers 4, 5 and 6, cords of which 2~ layers being crossed with each other with respect to the equatorial plane X-X. Among these steel cord layers, the innermost steel cord layer 6 has a split structure that the central portion of the layer is removed in the widthwise direction of the tire for reducing the cornering force of the tire. The width W1 of the middle 05 steel cord layer 5 is made larger than those of the other steel cord layers 4, 6 and is within a range of 80-llO~ of the tread width W, whereby the rigidity at the side end portion of the tread 3 is sufficiently increased and also the peeling at the end portion of the steel cord layer 5 from rubber is sufficiently prevented. The width W2 of each of the innermost steel cord layer 4 and the outermost steel cord layer 6 ls within a range of 80-98~ of the width W1 of the middle steel cord layer 5, whereby the rigidity at the side end portion of the tread and the durability of the belt are sufficiently increased and also the time of generating the cracking from the end of the belt layer can be delayed to delay the growth rate of the cracking.
Furthermore, the width W3 of the removed central portion in the innermost steel cord layer 6 is within a range of 15-50% of the width Wl of the middle steel cord layer 5, whereby the extreme reduction of the rigidity at the central portion of the tread 3 in the widthwise direction of the tire is prevented and also the effective reduction of the cornering force is achieved.
In the belt 2 of Fig. 3, the cord angle of each 2~.,,~.~.
of the steel cord layers 4, 5 and 6 with respect to the equatorial plane X-X is 45-80 upward to the right in the innermost layer, 1~-30 upward to the right in the middle layer and 10-~0 upward to the left in the 05 outermost layer. Alternatively, the cord directions of the innermost and middle layers may be upward to the left and the cord direction of the outermost layer may be upward to the right.
In the illustrated embodiment, plural sipes lO
are formed at an equal pitch in each of the five ribs 8, 9 defined by the four circumferential main grooves 7 having a depth of 5-30 mm. Moreover, these sipes may be arranged at an unequal pitch or may be formed only in the shoulder ribs.
1~ In the illustrated tire, these sipes lO having a width of not more than l mm and a depth corresponding to 10-110% of the depth of the main groove are formed at an equal pitch of, for example, 5-40 mm in the circumfer-ential direction of the tire. As shown in Fig. 4, the sipe lO is an open sipe, both ends of which being opened to side faces of the ribs 8, 9. Furthermore, the sipe lO may be a sipe, at least one end of which being terminated in the rib.
The whole of the sipe lO is extended at the same side as in the extending direction of the cords ll of the outermost steel cord layer 4 with respect to the 2~
equatorial plane X-X likewise Figs. 2 and 3.
The inclination angle of the sipe lO with respect to the equatorial plane X-X is preferable to be within a ranye of 40-90. That is, the sipe having the inclination 05 angle of 90 contributes to most effectively improve the wear resistance, while when the inclination angle is less than 40, the opposed side walls of the sipe always comes into contact with each other during the rotation of the tire under loading, and the function of the sipe itself can not substantially be developed.
The occurrence of the sipe tear can effectively be prevented owing to the presence of such sipes likewise the aforementioned embodiments.
According to the tire of Fig. 4, the cornering force not required for this type of the tire can effectively be reduced without sacrificing the rigidity at the side end portion of the tread and the durability of the belt 2, whereby the wear resistance and particularly uneven wear resistance of the tire can largely be improved.
In Fig. 5 is shown a fourth embodiment of the heavy duty pneumatic radial tire according to the invention. This tire is a modified embodiment of Fig. 4, wherein the tread portion 3 is divided by two circumferential main grooves 7 having a depth of 5-30 mm into three ribs 8, 9 and a fine groove 12 extending 26~
straight in the circumferential direction of the tire is arranged in each of the shoulder ribs ~ at a position within 15 mm from the side end of the outermost steel cord layer 4 in the widthwise direction of the tire.
05 Moreover, the fine yroove 12 may be extended zigzag in the circumferential direction. The fine groove 12 has a groove width of not more than 2 mm at a state of inflating under a given internal pressure and a depth corresponding to 50-110% of the depth of the circumferential main groove.
In this embodiment, the progress of edge wear generated at the side end portion of the tread inward in the widthwise direction of the tire can substantially completely be prevented by the action of the fine groove 12. Further, since the groove width of the fine groove 12 is not more than 2 mm under a given internal pressure, the occurrence of river wear from both the edge portions of the fine groove can be prevented.
Moreover, the reason why the depth of the fine groove is limited to 50-110% of the depth of the circumferential main groove is due to the fact that when the depth is not less than 50%, it is prevented to act the same cornering force as in the case of no fine groove to the portion of the rib located inward from the fine groove in the widthwise direction of the tire, while when it is not more than 110%, the occurrence of cracking at the groove bottom is prevented.
In Fig. 6 is shown a fifth embodiment of the heavy duty pneumatic radial tire according to the invention, which is a modified embodiment of Fig. 2.
0S In this case, the belt 2 is comprised of two belt layers 4, 5, cords of which layers being crossed with each other with respect to the equatorial plane X-X.
Moreover, the belt may be comprised of plural belt layers. The inclination angle of cords in these belt layers 4, 5 with respect to the equatorial plane X-X is 10-30 upward to the left in the outer belt layer 4 and 10-30 upward to the right in the inner belt layer 5.
Moreover, coating rubber for these belt layers and rubber arranged between the belt layers are prefer-1~ able to have a 100% tensile modulus of 50-90 kgf/cm2 in order to sufficiently reduce the shearing strain of rubber between the belt layers. On the other hand, the tread portion 3 is favorable to be made from rubber con-taining not less than 15% of natural rubber for prevent-ing the degradation of cut resistance and chippingresistance. Such rubbers are, of course, applied to all of the embodiments as previously mentioned.
In the embodiment of Fig. 6, when the width of the belt layer 4 is narrower than that of the belt layer 2~ 5 as shown in Fig~ 6, the thickness between the adjoining belt layers 4 and 5 crossing cords with 2~ 34~;
respect to the equatorial plane X-X is made 2-5 times at a side edge position E of the narrow-width belt layer 4 thicker than the thickness T at a central portion C of the belt layer in widthwise direction of the tire.
05 Moreover, the term "thickness of rubber between belt layers" used herein means a distance between inner edge of the cord of the outer belt layer 4 in the radial direction of the tire and outer edge of the cord of the inner belt layer 5 in the radial direction of the tire.
Further, the tread portion 3 is divided by two circumferential main grooves 7 into three ribs 8, 9 likewise the case of Fig. 5. Each of these ribs, particularly shoulder ribs 8 is provided with plural sipes 10 (not shown) and may be provided with plural lateral grooves, if necessary.
According to the tire of Fig. 6, the affect of rubber located in the vicinity of each of the belt layers 4, 5 by the other belt layer is sufficiently made small in the deformation of the tire during the rotation under loading, whereby the shearing strain of rubber located at the side end portions of the belt layers 4, 5 and the vicinity thereof can be largely reduced as compared with the conventional technique. Consequently, the pecking of rubber by cord ends at the side edges of the belt layers 4, 5 can sufficiently be reduced to effectively delay the occurrence time of cracking in rubber.
In addition to the above embodiments/ the invention is applicable to slick tires. Further, block pattern, lug pattern and a combination of two or more 05 kind of patterns may be used as a tread pattern in addition to the rib pattern.
The following examples are given in illustration of the invention and are not intended as limitations thereof.
10 Example 1 The state of generating sipe tear was examined with respect to the following three test tires having a tire size of TBR El3.50/85 Rl6.
The first test tire was a tire having a tread 1~ pattern shown in Fig. 2 (the extending direction of the outer end portion of the sipe is 70 with respect to the equatorial plane), and the second test tire was a tire having a tread pattern shown in Fig. 3 (the extending direction of the outer end portion of the sipe is 50 with respect to the equatorial plane), and the third test tire was a tire having a tread pattern shown in Fig. 1 (the extending direction of the outer end portion of the sipe is 130 with respect to the equatorial plane).
Each of these test tires had the following dimensions:
2~
nnermost belt layer:width of 190 mm, cord angle of 70 upward to the right with respect to the equatorial plane Middle belt layer: width of 210 mm, cord angle of 20 upward to the right with respect to the equatorial plane Outermost belt layer:width of 145 mm, cord angle of 20 upward to the left with respect to the equatorial plane Tread width: 216 mm Circumferential main groove: depth of 8 mm, maximum width of 18 mm, minimum width of 12 mm Distance between groove bottom of circumferential main groove and belt: 5 mm Internal pressure: 11.7 kgf/cm2 Each of these test tires was mounted onto a driving wheel of subway vehicle and actually run over a distance of 100,000 km. Thereafter/ the state of generating the sipe tear was visually observed to obtain results as shown in the following Table 1.
Table 1 Tire of Fig.2 Tire of Fig.3 Tire of Fig.l State of many sipe tears generating no occurrence no occurrence of 5 mm in sipe tear length occurred 2~
As seen from Table l, the tires according to the invention can considerably reduce the occurrence of the sipe tear as compared with the conventional tire.
Example 2 05 The wear resistance, uneven wear resistance and state of generating sipe tear were measured with respect to the .following two test tires having a tire size of El3.50/85 Rl6.
Invention tire: It was a tire having a tread pattern shown in Fig. ~, wherein the cord angle of the innermost belt layer with respect to the equatorial plane was 65 upward to the right, the cord angle of the middle belt layer was 20 upward to the right, the cord angle of the outermost belt layer was 20 upward to the left, the width of the removed portion of the innermost belt layer was 30% of the width of the middle belt layer, and the sipe was inclined at an angle of 70 upward to the left with respect to the equatorial plane and had a width of not more than l mm and a depth of 8.2 mm, and the sipe interval was 15 mm in the circumferential direction of the tire, and the depth of the circumferential main groove was 9.7 ~n.
Conventional tire: It was a tire having a tread pattern o~ shown in Fig. 1, wherein the angle of each end portion of the sipe with respect to the equatorial plane was 70 and the other constructions were the same as in the invention tire.
Each of these test tires was mounted onto a rim of 9.00 V x 16 at the driving shaft of the subway vehicle and run at an internal pressure of 9.8 kgf/cm2 in a track over a distance of 100,000 km. Thereafter, the state of generating sipe tear was visually observed, and the wear resistance was evaluated by measuring the worn amount from the remaining amount of the circumfer-ential main groove, and the uneven wear resistance was evaluated by measuring the difference of worn amount between central rib and shoulder rib.
The measured results are shown in the following Table 2. Moreover, each of the wear resistance and uneven wear resistance is represented by an index on the basis that the conventional tire is 100. The larger the index value, the better the property.
2~
Table 2 Tire performances Conventional tire Invention tire Wear resistance 100 130 Uneven wear resistance 100 300 State of generating many s pe tears no occurrence As seen ~rom Table 2/ the invention tire is fairly excellent in all tire performances as compared with the conventional tire.
Example 3 The state of generating uneven wear was measured with respect to the following three test tires having a tire size of E315/75 R22.5.
Invention tire: It was a tire having a tread pattern shown in Fig. 5, wherein the cord angle of the innermost belt layer with respect to the equatorial plane was 65 upward to the right, the cord angle of the middle belt layer was 20 upward to the right, the cord angle of the outermost belt layer was 20 upward to the left, the width of the removed portion of the innermost belt layer was 30% of the width of the middle belt layer r and the fine groove was formed in the tread portion at a position of 2 mm outward from the side edge of the outermost belt layer in the widthwise direction of the tire and had a groove width of l mm 05 under a given internal pressure and a depth corresponding to 9o% of the depth of the circumferential main groove.
Comparative tire I: It has the same constructions as in the invention tire except the absence of the fine groove.
Compaxative tire ~: It had the same constructions as in the invention tire except that the innermost belt layer had no split structure.
Each of these test tires was mounted onto a rim of 9.00x22,5 at the driving shaft of the subway vehicle and run under an internal pressure of 9.0 kgf/cm2 over a distance of lO0,000 km. Thereafter, the state of generating uneven wear was observed visually to obtain results as shown in the following Table 3.
2~
Table 3 ..._ _ Comparatlve Comparatlve Invent~on tlre tire I tire ~
The edge wear was The edge wea} The edge wear was generated at a por- of shoulder rib generated at the tion located outward was generated portion located from the fine groove over a full outward from the in the widthwise width of the fine groove in the State of direction of the shoulder rib. widthwise direc-generating tire, while no edge tion of the tire uneven wear wear was generated and progressed up at a portion located to a portion inward from the fine located inward groove, so that the from the fine tire was uniformly groove.
worn as a whole.
As seen from Table 3, according to the inventiontire/ the innermost belt layer has a split structure and the fine groove extending in the circumferential direction is arranged in the gîven region of the shoulder portion, so that the progress of edge wear generated in the side end portion of the tread inward the widthwise direction of the tire can be prevented very effectively.
Example 4 The state of generating the cracking in rubber from side end portions of the adjoining belt layers, cords of which layers being crossed with each other with respect to the equatorial plane of the tire, was measured with respect to the following three test tires having a tire size of E13.50/85 R16.
Invention tire: It was a tire having the construction shown in Fig. 6, wherein the cord angle of each of the adjoining belt layers with respect to the equatorial 05 plane of the tire was 20, and rubber in the each belt layer and between these belt layers had lO0~ tensile modulus of 70 kgf/cm2, and the thick-ness of rubber between the adjoining belt layers at the side end portion thereof was 3.0 times thicker than that (l mm) of the central portion.
Comparative tire: It has the same construction as in the invention tire except that the 16 thickness of rubber at the side end portion was 5.5 times than that (l mm) of the central portion.
Conventional tire: The thickness of rubber at the side end portion was l.5 times than that (l mm) of the central portion.
Each of these test tires was mounted onto a rim of 9.00V x 16 and run on a drum testing machine at an internal pressure of ll.7 kgf/cm2 over a distance of lO0,000 km. Thereafter, the state of generating rubber cracking from the end portion of the belt layer was 2~
observed to obtain results as shown in the follo~ing Table 4.
Table ~
Pt're Comparative tire Invention tire Cracks of not Cracks of not less than The occurrence less than lOmm lOmm in length were of cracking was in length were generated from end observed at State of generated from portions of adjoining portions of cracking end portions belt layers, while adjoining belt occurrence of adjoinin~ rubber located at the layers, but the belt layers. cracked portion length thereof exhibited a thermal was very small.
fract~re form.
AS mentioned above, according to the invention, the portion of the sipe having a largest deformation amount is particularly extended at the same side as in the extending direction of the cords of the outermost belt layer with respect to the equatorial plane of the tire, so that the occurrence of sipe tear can largely be reduced. Furthermore, the wear resistance and uneven wear resistance can considerably be improved by taking the split structure in the innermost belt layer among the plural belt layers. Moreover, the progress of edge wear generated at the side end portion of the tread inward the circumferential direction of the tire can sufficiently be prevented to prolong the life of the tire by arranging the fine groove in the shoulder rib at 20~ ri~
a given position. In addition, the thickness of rubber between the adjoining belt layers is made thicker at the side end portion of the belt layer than at the central portion thereof, whereby the occurrence of crackiny in 05 rubber from the outward side end of the belt layer can effectively be suppressed to largely improve the durability of the tire.
Furthermore, numeral 56 is a tread portion.
This tread portion 56 is provided with five ribs 58 and 59 defined by four circumferential main grooves 57 extending zigza~ in the circumEerential direction.
05 Moreover, each of shoulder ribs 58 located at the shoulder portions of the tire is provided with plural sipes 60 arranged at substantially an equal interval in the circumferential direction of the tire.
In this case, each sipe 60 is a so-called blind sipe, both ends of which being terminated in the shoulder ribO Further r the central portion of the sipe 60 in the widthwise direction of the tire extends in the same direction as in the extending direction of cords 53a of the outermost belt layer 53 with respect to the equatorial plane X-X of the tire.
When the tire of this type is usually used under a high internal pressure of 9-12 kgf/cm2, the sipe 60 tends to enlarge in the widthwise direction.
In addition, the cords 53a of the outermost belt layer 53 is subjected to a lar~e tensile force at the stepping-in state, a compressive force at the ground contacting state and a tensile force at the kicking-out state during the rotating of the tire under loading.
Consequently, when fold end portions 60a and 60b extendin~ from the central portion of the sipe 60 are opposite to the extending direction of the cord 53a of 2~ 9'~
the outermost belt layer 53 with respect to the equatorial plane X-X of the tire as shown in Fig. l, an outer end portion of the sipe 60 in widthwise direction of the tire having a largest deformation amount is 05 particularly deformed in a direction of more enlarging the width of the sipe every the action of tensile force to the cord 53a, so that there is caused a problem that cracking toward the surface of the shoulder rib due to stress concentration or a so-called sipe tear is caused from the outer end position of the sipe 60 in the widthwise direction of the tire.
Moreover, if the sipe 60 is opened to the side end face of the tread portion 56, there is a problem of causing another kind of sipe tear from the sipe bottom at the opened end of the sipe 60 toward the sidewall.
Further, in order to sufficiently enhance the rigidity of the tread portion 56 for the improvement of wear resistance and traction performances in the conventional tire, the belt 52 is comprised of three steel cord layers 53, 54 and 55 each being continuously embedded from one side end to the other side end in the widthwise direction of the tire. Therefore, when the vehicle provided with such tires is steered through the action of a guide wheel contacting with a side wall of a track t guide plate or the like, an unnecessary and large cornering force is created in the tire rotating under loading to apply a large input from tne road surface to the ground contacting surface of the tire, whereby the ground contacting surface of the tire is apt to be subjected to an uneven wear at the side end portion of 05 the tread due to the dragging. Consequently, there may be a problem that such an uneven wear prematurely progresses toward the center of the tread portion in the widthwise direction.
Moreover, in such conventional tires, the thickness of rubber between adjoining belt layers 53 and 54, the cords of which layers being extended in an opposite direction with each other with respect to the equatorial plane of the tire is generally made relatively thin and uniform over a full width of the belt layer. When the tire is deformed during the rotation under loading, rubber located at the side end portions of the belt layers 53, 54 and in the vicinity thereof is subjected to a large shearing deformation based on the difference of the deformation behavior between the adjoining belt layers 53 and 54, and is apt to be damaged through the pecking with cord ends of the side end portions of the belt. As a result, there may be a highly fear that the occurrence of cracking at the damaged rubber and hence separation between belt layers 26 and other serious troubles are generated at a relatively premature period.
4~
It is, therefore, an object of the invention to solve the aforementioned problems of the conventional tires and provide a heav~v duty pneumatic radial tire used under high internal pressure capable of effectively 06 preventing the occurrence of sipe tear.
It is another object of the invention to provide a heavy duty pneumatic radial tire used under high internal pressure which can advantageously restrain the occurrence of uneven wear by sufficiently reducing the cornering force and can effectively prevent the occurrence of sipe tear and the growth of edge wear at the side end portion of the tread inward the widthwise direction of the tire, which has not completely avoided in the conventional tire.
It is the other object of the invention to provide a heavy duty pneumatic radial tire used under high internal pressure which can further delay the occurrence time of cracking in rubber at side end portions of the belt layer and the vicinity thereof.
According to the invention, there is the provision of a heavy duty pneumatic radial tire used under high internal pressure comprising a carcass composed of at least one carcass ply, a belt composed of plural belt layers, cords of which layers being extended 2~ in a direction crossing with an equatorial plane of the tire, a tread portion and plural sipes arranged in each shoulder of the tread portion at a given interval in the circumferential direction of the tire, characterized in that at least an end portion of each of said sipes located in the vicinity of a side edge of an outermost o~ belt layer is extended at the same side as in an extending direction of cords of said outermost belt layer with respect to the equatorial plane of the tire.
In a preferred embodiment of the invention, the belt is comprised of three steel cord layers, wherein an innermost steel cord layer of the belt has a split structure that a central portion of this steel cord layer is removed in the widthwise direction of the tire7 and a middle steel cord layer is made wider than innermost and outermost steel cord layers, and a width of the middle steel cord layer is 80-110% of a tread width and a width of each of the innermost steel cord layer and outermost steel cord layer is within a range of 80-98% of the width of the middle steel cord layer provided that a width of the removed portion of the innermost steel cord layer is within a range of 15-50%
of the width of the middle steel cord layer.
In another preferred embodiment of the invention, when the belt is comprised of three steel cord layers as mentioned above, a fine groove is further arranged in the tread portion toward the circumferential direction so as to extend outward from a side edge of 2~139~
the outermost steel cord layer within a range of not more than 15 mm in the widthwise direction of the tire.
In the other preferred embodiment of the invention, a thickness of rubber between the adjoining o~ belt layers, cords of which layers being crossed with each other with respect to the equatorial plane of the tire, is made 2-5 times at an outward end portion of the belt layer thicker than that at a central portion of the belt layer in widthwise direction of the tire.
The invention will be described with reference to the accompanying drawings, wherein:
Fig. 1 is a schematic view of the conventional xadial tire;
Fig. 2 is a schematic view of a first embodiment of the radial tire according to the invention;
Fig. 3 is a schematic view of a second embodi-ment of the radial tire according to the invention;
Fig. 4 is a schematic view of a third embodiment of the radial tire according to the invention;
Fiy. 5 is a schematic view of a fourth embodi-ment of the radial tire according to the invention; and Fig. 6 is a schematically sectional view of a fifth embodiment of the radial tire according to the invention.
In the heavy duty pneumatic radial tire used under high internal pressure according to the invention, ~o~9~
plural sipes are arranged in each of the shoulder ribs at a given interval toward the circumferential direction of the tire, wherein at least an end portion of each of the sipes in the shoulder located in the vicinity of the 05 side end of the outermost belt layer is extended at the same side as in the extending direction of cords of the outermost belt layer with respect to the equatorial plane of the tire. Thus, since the extending direction of the end portion of the sipe is same as in the cord direction of the outermost belt layer with respect to the equatorial plane, when a force in tensile direction is applied to the cords of the belt, the end portion of the sipe is subjected to a deformation in a direction reducing the sipe width, whereby the concentration of stress at the end of the sipe can effectively be mitigated to sufficiently prevent the occurrence of sipe tear from the end of the sipe. This is true whatever the outer end of the sipe is terminated in the shoulder rib or opened to the side end face of the tread portion.
Moreover, the extending direction of the end portion of the sipe means to include both a direction of zero degree with respect to the equatorial plane of the tire and a direction of zero degree with respect to the meridional plane of the tire. In fact, even when the 26 end portion of the sipe is existent at an angle of zero degree with respect to the equatorial plane or with 9~
respect to the meridional plane, the occurrence of sipe tear can effectively be prevented as compared with the conventional technique that the extending direction of the end portion of the sipe is opposite to the cord 05 direction of the outermost belt layer with respect to the equatorial plane.
When the belt is comprised of three steel cord layers, the innermost steel cord layer acting to control the growth of the tire in radial direction has a split structure, so that the function of the belt itself can sufficiently be developed and the cornering force can advantageously be reduced without degrading the rigidity at the side end portion of the tread and the durability of the belt, whereby the occurrence of uneven wear resulted from the application of large input from the road surface to the ground contacting portion of the tire can effectively be prevented. If the belt layer other than the innermost steel cord layer has a split structure, it is impossible to obtain a uniform crown shape during the inflation of the tire under a given internal pressure.
The reason why the width of the middle steel cord layer is made wider than those of the other steel cord layers and is within a range of 80-110% of the 2~ tread width is based on the fact that the region up to the side end portion of the tread is sufficiently 2~
reinforced to advantageously improve the wear resistance of the side end portion and also the increase of the end portion of the middle steel cord layer in radial direction is effectively suppressed. Further, the 05 reason why the width of each of the innermost and outermost steel cord layers is within a range of 80-98 of the width of the middle steel cord layer is due to the fact that when the width is less than 80%, the rigidity of the side end portion of the tread and the belt durability can not sufficiently be increased, while when it exceeds 98%, the premature occurrence of cracking in rubber from the end of the belt layer is caused and the growth of crack becomes fast.
Moreover, the reason why the width of the removed portion in the innermost steel cord layer is within a range of 15-50% of the width of the middle steel cord layer is due to the fact that when the width is less than 15~, the effective reduction of cornering force can not be achieved, while when it exceeds 50%, the rigidity at both side end portions of the tread in widthwise direction becomes too low.
Furthermore r when the fine groove extending in the circumferential direction of the tire is arranged in each side end portion of the tread, the progress of edge wear generated at the side end portion of the tread inward in the widthwise direction of the tire can z~
effectively be prevented. For example, when the ~ine groove is arranged in each of the shoulder ribs defined by main circumferential grooves, a portion of the shoulder rib located outward from the fine groove in the o~ widthwise direction of the tire opposes to the input of side force to cause an edge wear~ while a portion of the shoulder rib located inward from the fine groove in the widthwise direction of the tire is small in the bearing the input of side force and the progress of the above edge wear thereinto is prevented by the fine groove, so that the uniform wear state is exhibited without causing the edge wear.
On the other hand, the reason why the position of the fine groove arranged in the tread portion is 15 mm from the side edge of the outermost belt layer in the widthwise direction of the tire is due to the fact that when the fine groove is located over 15 mm outward in the widthwise direction of the tirel the input of side force to the edge of the rib portion located inside the fine groove in the widthwise direction of the tire increases, while when the fine groove is located over 15 mm inward in the widthwise direction of the tire, the width of edge wear at the rib portion located outside the fine groove in the widthwise direction of the tire is wider, Further, in order to prevent the occurrence of ~t~
cracking from the bottom of the fine groove toward the side edge of the belt layer, it is favorable to locate the fine groove inward from the side edge of the belt layer in the widthwise direction of the tire.
OS Preferably, when the width of the fine groove is not more than 2 mm at an inflation state under an internal pressure, the opposed groove walls of the fine groove are contacted with each other during the running of the tire under loading to prevent the occurrence of river wear from the both edge portions of the fine groove. In addition, when the depth of the fine groove is within a range of 50-110% of the depth of the circumferential main groove and is, for example, within a range of 5-30 mm, the progress of edge wear inward in the widthwise direction of the tire is sufficiently prevented and also the occurrence of cracking from the bottom of the fine groove is sufficiently prevented.
Moreover, when the thickness of rubber between the adjoining belt layers crossing cords with each other with respect to the equatorial plane is made 2-5 times at the outward end portion of the belt layer in widthwise direction thereof thicker than that at the central portion of the belt layer in widthwise direction thereof, strain quantity of rubber located at the outward end portion of the belt layer or its vicinity and showing a largest shearing strain to the belt layer ~o~
can be considerably reduced as compared with the conventional techni~ue when the tire is inflated and rotated under a load. Consequently, the quantity of rubber pecked by the cord ends at the side edge of the 05 belt layer is sufficiently reduced and the occurrence time of cracking in rubber can largely be delayed.
The reason why the thickness of rubber between the adjoining belt layers is made 2-5 times at the outward end portion of the belt layer thicker than that at the central portion of the belt layer in widthwise direction of the tire is due to the fact that when the thickness is less than 2 times, the occurrence of cracking in rubber at the belt end portion and its vicinity can not be delayed, while when it exceeds 1~ 5 times, the occurrence of cracking can not effectively be delayed but also thermal breakage of rubber is caused due to heat accumulated in rubber.
Accordlng to the invention, it is preferable that 100% tensile modulus of rubber located inside the belt layer and between the belt layers is 50-90 kg/cm2.
In this case, the shearing strain of rubber between the adjoining belt layers can be more reduced to delay the occurrence of cracking in rubber, and also the increase of circumferential length of the tire can advantageously be reduced in the inflation of the tire. When the 100%
tensile modulus is less than 50 kg/cm2, the shearing 2~
strain becomes too large, while when it exceeds 90 kg/cm2, the rigidity of rubber becomes too high to degrade the crack resistance of rubber.
Moreover, it is favorable that the angle of o~ cords in the belt layers extending in opposite directions to each other is within a range of 10-30 with respect to the equatorial plane of the tire. Thus, the increase of circumferential length of the tire can sufficiently be suppressed in the inflation of the tire and during the rotation under a load.
When the cord angle with respect to the equatorial plane of the tire is less than 10, the shearing strain at widthwise cord end portion of the belt layers crossing in opposite directions to each other increases to cause premature occurrence of cracking in rubber at the widthwise end portion of the belt layer, while when it exceeds 30, the growth of the belt layer in radial direction becomes large in the inflation under high internal pressure and also the shearing strain at widthwise end portion of the crossed belt layers increases to cause premature occurrence of cracking in rubber at the widthwise end portion of the belt layer.
In Fig. 2 is shown a first embodiment of the heavy duty pneumatic radial tire according to the invention, wherein numeral 1 is a carcass, numeral 2 a 2~ t~
belt superimposed about a crown portion of the carcass l, and numeral 3 a tread portion forming a ground contacting portion of the tire.
The carcass l is comprised of at least one 05 carcass ply containing cords arranged substantially in the radial direction of the tire, while the belt 2 is comprised of plural belt layers, cords of which layers crossing with each other with respect to the equatorial plane X-X of the tire. In this embodiment, the belt 2 is comprised of three belt layers 4, 5 and 6.
In the tread portion 3, five ribs 8 and 9 extending in the circumferential direction of the tire are defined by four circumferential main grooves 7.
At least shoulder ribs 8 among these ribs (only shoulder ribs in this embodiment) are provided with plural sipes lO located at substantially an equal interval in the circumferential direction of the tire.
As seen from the upper half portion of Fig. 2, each of these sipes lO is a blind sipe, both ends of which being terminated in the shoulder rib. Further, each sipe lO is extended at the same side as in the extending direction of cords ll of the outermost belt 1.ayer 4 with respect to the equatorial plane X-X of the tire over the full length of the sipe. Thus, the outer end portion of the sipe lO in the widthwise direction of the tire being largest in the deformation amount, or the end portion located in the vicinity of the side edge of the outermost belt layer 4 in the widthwise direction of the tire also directs at the same side as in the direction of the cord ll of the outermost belt layer 4.
05 The feature that the direction of the sipe 10 is the same side as in the extending direction of the cords of the outermost belt layer 4 with respect to the e~uatorial plane X-X means that the sipe lO is extended in the same quadrant as in the cords 11 when orthogonal coordinates are defined by a line segment parallel to the equatorial plane X-X and the meridional plane of the tire at proper position on the sipe and proper position on the cord. In this case, the extending direction of the sipe lG may be coincident with the co-ordinate axis.
In the illustrated embodiment, either end of the sipe lO may be opened to the groove wall of the circumferential main groove 7 or the side end face of the tread portion 3 alternately or entirely.
According to the tire of the illustrated embodiment r even when the large tensile force is applied to the cords 11 of the outermost belt layer 4 at the stepping-in and kicking-out states during the rotation under loading, it brings about the deformation of reducing the sipe width at the outer end portion of the sipe 10 in widthwise direction of the tire being largest in the deformation amount, whereby the occurrence of 2~3~3~
cracking from the outer end of the sipe toward the surface of the shoulder rib is effectively prevented.
This is particularly effective when the extending direction of the sipe lO is coincident with the 05 extending direction of the cord ll in the aforementioned orthogonal coordinates.
Similarly, such a deformation behavior at the outer end portion of the sipe is caused when the one end of the sipe lO is opened to the side end face of the tread portion 3. That is, the tensile force acting to the cord ll does not enlarge the width of the sipe lO
but causes the deformation of reducing the sipe width, so that the occurrence of cracking toward the side end face of the tread portion is effectively prevented.
Thus, according to the illustrated tire, the sipe tear generated from the end of the sipe lO being largest in the deformation amount can be prevented effectively.
In Fig. 3 is shown a second embodiment of the heavy duty pneumatic radial tire according to the invention, which is a modified embodiment of Fig. 2.
That is, only the outer folded end portion of each of the sipes lO arranged in the shoulder rib 8, which is located in the vicinity of the side end of the outermost belt layer 4, is extended at the same side as in the extending direction of the cords ll of the outermost belt layer 4 with respect to the equatorial plane X-X as shown at the orthogonal coordinates in Fig. 3.
In the embodiment of Fig. 3, the portion of the sipe lO being largest in the deformation amount, or the 05 portion apt to generate the sipe tear directs at the same side as in the extending direction of the cord 11, so that such an end portion of the sipe deforms in the direction of reducing the sipe width likewise the case of Fig. 2, and consequently the occurrence of sipe tear from the end of the sipe is effectively prevented.
Moreover, this is similar when the sipe end is opened to the side end face of the tread portion.
When the sipe is largely folded as shown in Fig. 3, it is favorable that the radius of curvature of the folded portion in the sipe is made large as far as possible in order to prevent the occurrence of sipe tear from the folded point.
Even in the embodiment of Fig. 3, the occurrence of sipe tear can be prevented sufficiently.
In Fig. 4 is shown a third embodiment of the heavy duty pneumatic radial tire according to the invention, which is a modified embodiment of Fig. 2.
In this embodiment, the belt 2 is comprised of three steel cord layers 4, 5 and 6, cords of which 2~ layers being crossed with each other with respect to the equatorial plane X-X. Among these steel cord layers, the innermost steel cord layer 6 has a split structure that the central portion of the layer is removed in the widthwise direction of the tire for reducing the cornering force of the tire. The width W1 of the middle 05 steel cord layer 5 is made larger than those of the other steel cord layers 4, 6 and is within a range of 80-llO~ of the tread width W, whereby the rigidity at the side end portion of the tread 3 is sufficiently increased and also the peeling at the end portion of the steel cord layer 5 from rubber is sufficiently prevented. The width W2 of each of the innermost steel cord layer 4 and the outermost steel cord layer 6 ls within a range of 80-98~ of the width W1 of the middle steel cord layer 5, whereby the rigidity at the side end portion of the tread and the durability of the belt are sufficiently increased and also the time of generating the cracking from the end of the belt layer can be delayed to delay the growth rate of the cracking.
Furthermore, the width W3 of the removed central portion in the innermost steel cord layer 6 is within a range of 15-50% of the width Wl of the middle steel cord layer 5, whereby the extreme reduction of the rigidity at the central portion of the tread 3 in the widthwise direction of the tire is prevented and also the effective reduction of the cornering force is achieved.
In the belt 2 of Fig. 3, the cord angle of each 2~.,,~.~.
of the steel cord layers 4, 5 and 6 with respect to the equatorial plane X-X is 45-80 upward to the right in the innermost layer, 1~-30 upward to the right in the middle layer and 10-~0 upward to the left in the 05 outermost layer. Alternatively, the cord directions of the innermost and middle layers may be upward to the left and the cord direction of the outermost layer may be upward to the right.
In the illustrated embodiment, plural sipes lO
are formed at an equal pitch in each of the five ribs 8, 9 defined by the four circumferential main grooves 7 having a depth of 5-30 mm. Moreover, these sipes may be arranged at an unequal pitch or may be formed only in the shoulder ribs.
1~ In the illustrated tire, these sipes lO having a width of not more than l mm and a depth corresponding to 10-110% of the depth of the main groove are formed at an equal pitch of, for example, 5-40 mm in the circumfer-ential direction of the tire. As shown in Fig. 4, the sipe lO is an open sipe, both ends of which being opened to side faces of the ribs 8, 9. Furthermore, the sipe lO may be a sipe, at least one end of which being terminated in the rib.
The whole of the sipe lO is extended at the same side as in the extending direction of the cords ll of the outermost steel cord layer 4 with respect to the 2~
equatorial plane X-X likewise Figs. 2 and 3.
The inclination angle of the sipe lO with respect to the equatorial plane X-X is preferable to be within a ranye of 40-90. That is, the sipe having the inclination 05 angle of 90 contributes to most effectively improve the wear resistance, while when the inclination angle is less than 40, the opposed side walls of the sipe always comes into contact with each other during the rotation of the tire under loading, and the function of the sipe itself can not substantially be developed.
The occurrence of the sipe tear can effectively be prevented owing to the presence of such sipes likewise the aforementioned embodiments.
According to the tire of Fig. 4, the cornering force not required for this type of the tire can effectively be reduced without sacrificing the rigidity at the side end portion of the tread and the durability of the belt 2, whereby the wear resistance and particularly uneven wear resistance of the tire can largely be improved.
In Fig. 5 is shown a fourth embodiment of the heavy duty pneumatic radial tire according to the invention. This tire is a modified embodiment of Fig. 4, wherein the tread portion 3 is divided by two circumferential main grooves 7 having a depth of 5-30 mm into three ribs 8, 9 and a fine groove 12 extending 26~
straight in the circumferential direction of the tire is arranged in each of the shoulder ribs ~ at a position within 15 mm from the side end of the outermost steel cord layer 4 in the widthwise direction of the tire.
05 Moreover, the fine yroove 12 may be extended zigzag in the circumferential direction. The fine groove 12 has a groove width of not more than 2 mm at a state of inflating under a given internal pressure and a depth corresponding to 50-110% of the depth of the circumferential main groove.
In this embodiment, the progress of edge wear generated at the side end portion of the tread inward in the widthwise direction of the tire can substantially completely be prevented by the action of the fine groove 12. Further, since the groove width of the fine groove 12 is not more than 2 mm under a given internal pressure, the occurrence of river wear from both the edge portions of the fine groove can be prevented.
Moreover, the reason why the depth of the fine groove is limited to 50-110% of the depth of the circumferential main groove is due to the fact that when the depth is not less than 50%, it is prevented to act the same cornering force as in the case of no fine groove to the portion of the rib located inward from the fine groove in the widthwise direction of the tire, while when it is not more than 110%, the occurrence of cracking at the groove bottom is prevented.
In Fig. 6 is shown a fifth embodiment of the heavy duty pneumatic radial tire according to the invention, which is a modified embodiment of Fig. 2.
0S In this case, the belt 2 is comprised of two belt layers 4, 5, cords of which layers being crossed with each other with respect to the equatorial plane X-X.
Moreover, the belt may be comprised of plural belt layers. The inclination angle of cords in these belt layers 4, 5 with respect to the equatorial plane X-X is 10-30 upward to the left in the outer belt layer 4 and 10-30 upward to the right in the inner belt layer 5.
Moreover, coating rubber for these belt layers and rubber arranged between the belt layers are prefer-1~ able to have a 100% tensile modulus of 50-90 kgf/cm2 in order to sufficiently reduce the shearing strain of rubber between the belt layers. On the other hand, the tread portion 3 is favorable to be made from rubber con-taining not less than 15% of natural rubber for prevent-ing the degradation of cut resistance and chippingresistance. Such rubbers are, of course, applied to all of the embodiments as previously mentioned.
In the embodiment of Fig. 6, when the width of the belt layer 4 is narrower than that of the belt layer 2~ 5 as shown in Fig~ 6, the thickness between the adjoining belt layers 4 and 5 crossing cords with 2~ 34~;
respect to the equatorial plane X-X is made 2-5 times at a side edge position E of the narrow-width belt layer 4 thicker than the thickness T at a central portion C of the belt layer in widthwise direction of the tire.
05 Moreover, the term "thickness of rubber between belt layers" used herein means a distance between inner edge of the cord of the outer belt layer 4 in the radial direction of the tire and outer edge of the cord of the inner belt layer 5 in the radial direction of the tire.
Further, the tread portion 3 is divided by two circumferential main grooves 7 into three ribs 8, 9 likewise the case of Fig. 5. Each of these ribs, particularly shoulder ribs 8 is provided with plural sipes 10 (not shown) and may be provided with plural lateral grooves, if necessary.
According to the tire of Fig. 6, the affect of rubber located in the vicinity of each of the belt layers 4, 5 by the other belt layer is sufficiently made small in the deformation of the tire during the rotation under loading, whereby the shearing strain of rubber located at the side end portions of the belt layers 4, 5 and the vicinity thereof can be largely reduced as compared with the conventional technique. Consequently, the pecking of rubber by cord ends at the side edges of the belt layers 4, 5 can sufficiently be reduced to effectively delay the occurrence time of cracking in rubber.
In addition to the above embodiments/ the invention is applicable to slick tires. Further, block pattern, lug pattern and a combination of two or more 05 kind of patterns may be used as a tread pattern in addition to the rib pattern.
The following examples are given in illustration of the invention and are not intended as limitations thereof.
10 Example 1 The state of generating sipe tear was examined with respect to the following three test tires having a tire size of TBR El3.50/85 Rl6.
The first test tire was a tire having a tread 1~ pattern shown in Fig. 2 (the extending direction of the outer end portion of the sipe is 70 with respect to the equatorial plane), and the second test tire was a tire having a tread pattern shown in Fig. 3 (the extending direction of the outer end portion of the sipe is 50 with respect to the equatorial plane), and the third test tire was a tire having a tread pattern shown in Fig. 1 (the extending direction of the outer end portion of the sipe is 130 with respect to the equatorial plane).
Each of these test tires had the following dimensions:
2~
nnermost belt layer:width of 190 mm, cord angle of 70 upward to the right with respect to the equatorial plane Middle belt layer: width of 210 mm, cord angle of 20 upward to the right with respect to the equatorial plane Outermost belt layer:width of 145 mm, cord angle of 20 upward to the left with respect to the equatorial plane Tread width: 216 mm Circumferential main groove: depth of 8 mm, maximum width of 18 mm, minimum width of 12 mm Distance between groove bottom of circumferential main groove and belt: 5 mm Internal pressure: 11.7 kgf/cm2 Each of these test tires was mounted onto a driving wheel of subway vehicle and actually run over a distance of 100,000 km. Thereafter/ the state of generating the sipe tear was visually observed to obtain results as shown in the following Table 1.
Table 1 Tire of Fig.2 Tire of Fig.3 Tire of Fig.l State of many sipe tears generating no occurrence no occurrence of 5 mm in sipe tear length occurred 2~
As seen from Table l, the tires according to the invention can considerably reduce the occurrence of the sipe tear as compared with the conventional tire.
Example 2 05 The wear resistance, uneven wear resistance and state of generating sipe tear were measured with respect to the .following two test tires having a tire size of El3.50/85 Rl6.
Invention tire: It was a tire having a tread pattern shown in Fig. ~, wherein the cord angle of the innermost belt layer with respect to the equatorial plane was 65 upward to the right, the cord angle of the middle belt layer was 20 upward to the right, the cord angle of the outermost belt layer was 20 upward to the left, the width of the removed portion of the innermost belt layer was 30% of the width of the middle belt layer, and the sipe was inclined at an angle of 70 upward to the left with respect to the equatorial plane and had a width of not more than l mm and a depth of 8.2 mm, and the sipe interval was 15 mm in the circumferential direction of the tire, and the depth of the circumferential main groove was 9.7 ~n.
Conventional tire: It was a tire having a tread pattern o~ shown in Fig. 1, wherein the angle of each end portion of the sipe with respect to the equatorial plane was 70 and the other constructions were the same as in the invention tire.
Each of these test tires was mounted onto a rim of 9.00 V x 16 at the driving shaft of the subway vehicle and run at an internal pressure of 9.8 kgf/cm2 in a track over a distance of 100,000 km. Thereafter, the state of generating sipe tear was visually observed, and the wear resistance was evaluated by measuring the worn amount from the remaining amount of the circumfer-ential main groove, and the uneven wear resistance was evaluated by measuring the difference of worn amount between central rib and shoulder rib.
The measured results are shown in the following Table 2. Moreover, each of the wear resistance and uneven wear resistance is represented by an index on the basis that the conventional tire is 100. The larger the index value, the better the property.
2~
Table 2 Tire performances Conventional tire Invention tire Wear resistance 100 130 Uneven wear resistance 100 300 State of generating many s pe tears no occurrence As seen ~rom Table 2/ the invention tire is fairly excellent in all tire performances as compared with the conventional tire.
Example 3 The state of generating uneven wear was measured with respect to the following three test tires having a tire size of E315/75 R22.5.
Invention tire: It was a tire having a tread pattern shown in Fig. 5, wherein the cord angle of the innermost belt layer with respect to the equatorial plane was 65 upward to the right, the cord angle of the middle belt layer was 20 upward to the right, the cord angle of the outermost belt layer was 20 upward to the left, the width of the removed portion of the innermost belt layer was 30% of the width of the middle belt layer r and the fine groove was formed in the tread portion at a position of 2 mm outward from the side edge of the outermost belt layer in the widthwise direction of the tire and had a groove width of l mm 05 under a given internal pressure and a depth corresponding to 9o% of the depth of the circumferential main groove.
Comparative tire I: It has the same constructions as in the invention tire except the absence of the fine groove.
Compaxative tire ~: It had the same constructions as in the invention tire except that the innermost belt layer had no split structure.
Each of these test tires was mounted onto a rim of 9.00x22,5 at the driving shaft of the subway vehicle and run under an internal pressure of 9.0 kgf/cm2 over a distance of lO0,000 km. Thereafter, the state of generating uneven wear was observed visually to obtain results as shown in the following Table 3.
2~
Table 3 ..._ _ Comparatlve Comparatlve Invent~on tlre tire I tire ~
The edge wear was The edge wea} The edge wear was generated at a por- of shoulder rib generated at the tion located outward was generated portion located from the fine groove over a full outward from the in the widthwise width of the fine groove in the State of direction of the shoulder rib. widthwise direc-generating tire, while no edge tion of the tire uneven wear wear was generated and progressed up at a portion located to a portion inward from the fine located inward groove, so that the from the fine tire was uniformly groove.
worn as a whole.
As seen from Table 3, according to the inventiontire/ the innermost belt layer has a split structure and the fine groove extending in the circumferential direction is arranged in the gîven region of the shoulder portion, so that the progress of edge wear generated in the side end portion of the tread inward the widthwise direction of the tire can be prevented very effectively.
Example 4 The state of generating the cracking in rubber from side end portions of the adjoining belt layers, cords of which layers being crossed with each other with respect to the equatorial plane of the tire, was measured with respect to the following three test tires having a tire size of E13.50/85 R16.
Invention tire: It was a tire having the construction shown in Fig. 6, wherein the cord angle of each of the adjoining belt layers with respect to the equatorial 05 plane of the tire was 20, and rubber in the each belt layer and between these belt layers had lO0~ tensile modulus of 70 kgf/cm2, and the thick-ness of rubber between the adjoining belt layers at the side end portion thereof was 3.0 times thicker than that (l mm) of the central portion.
Comparative tire: It has the same construction as in the invention tire except that the 16 thickness of rubber at the side end portion was 5.5 times than that (l mm) of the central portion.
Conventional tire: The thickness of rubber at the side end portion was l.5 times than that (l mm) of the central portion.
Each of these test tires was mounted onto a rim of 9.00V x 16 and run on a drum testing machine at an internal pressure of ll.7 kgf/cm2 over a distance of lO0,000 km. Thereafter, the state of generating rubber cracking from the end portion of the belt layer was 2~
observed to obtain results as shown in the follo~ing Table 4.
Table ~
Pt're Comparative tire Invention tire Cracks of not Cracks of not less than The occurrence less than lOmm lOmm in length were of cracking was in length were generated from end observed at State of generated from portions of adjoining portions of cracking end portions belt layers, while adjoining belt occurrence of adjoinin~ rubber located at the layers, but the belt layers. cracked portion length thereof exhibited a thermal was very small.
fract~re form.
AS mentioned above, according to the invention, the portion of the sipe having a largest deformation amount is particularly extended at the same side as in the extending direction of the cords of the outermost belt layer with respect to the equatorial plane of the tire, so that the occurrence of sipe tear can largely be reduced. Furthermore, the wear resistance and uneven wear resistance can considerably be improved by taking the split structure in the innermost belt layer among the plural belt layers. Moreover, the progress of edge wear generated at the side end portion of the tread inward the circumferential direction of the tire can sufficiently be prevented to prolong the life of the tire by arranging the fine groove in the shoulder rib at 20~ ri~
a given position. In addition, the thickness of rubber between the adjoining belt layers is made thicker at the side end portion of the belt layer than at the central portion thereof, whereby the occurrence of crackiny in 05 rubber from the outward side end of the belt layer can effectively be suppressed to largely improve the durability of the tire.
Claims (6)
1. A heavy duty pneumatic radial tire used under high internal pressure comprising a carcass composed of at least one carcass ply, a belt composed of plural belt layers, cords of which layers being extended in a direction crossing with an equatorial plane of the tire, a tread portion and plural sipes arranged in each shoulder of the tread portion at a given interval in the circumferential direction of the tire, characterized in that at least an end portion of each of said sipes located in the vicinity of a side edge of an outermost belt layer is extended at the same side as in an extending direction of cords of said outermost belt layer with respect to the equatorial plane of the tire.
2. The heavy duty pneumatic radial tire according to claim 1, wherein said belt is comprised of three steel cord layers, and an innermost steel cord layer of said belt has a split structure that a central portion of this steel cord layer is removed in the widthwise direction of the tire, and a middle steel cord layer is made wider than innermost and outermost steel cord layers, and a width of said middle steel cord layer is 80-110% of a tread width and a width of each of said innermost steel cord layer and outermost steel cord layer is within a range of 80-98% of the width of said middle steel cord layer provide that a width of the removed portion of said innermost steel cord layer is within a range of 15-50% of the width of said middle steel cord layer.
3. The heavy duty pneumatic radial tire according to claim 1 or 2, wherein a fine groove is further arranged in said tread portion toward the circumfer-ential direction so as to extend outward from a side edge of said outermost steel cord layer within a range of not more than 15 mm in the widthwise direction of the tire.
4. The heavy duty pneumatic radial tire according to any one of claims 1 to 3, wherein a thickness of rubber between the adjoining belt layers, cords of which layers being crossed with each other with respect to the equatorial plane of the tire, is made 2-5 times at an outward end portion of the belt layer thicker than that at a central portion of the belt layer in the widthwise direction of the tire.
5. The heavy duty pneumatic radial tire according to claim 1, wherein rubber located in said belt layer and between adjoining belt layers has a 100% tensile modulus of 50-90 kgf/cm2.
6. The heavy duty pneumatic radial tire according to claim 3, wherein said fine groove has a groove width of not more than 2 mm under an inflation of internal pressure and a depth corresponding to 50-110% of a depth of a circumferential main groove extending circumferentially of the tire.
Applications Claiming Priority (8)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63-266,226 | 1988-10-24 | ||
| JP63266226A JPH02114007A (en) | 1988-10-24 | 1988-10-24 | Radial tire for high inner pressure and heavy load |
| JP63310204A JPH02158402A (en) | 1988-12-09 | 1988-12-09 | High internal pressure heavy loading radial-ply tire |
| JP63-310,204 | 1988-12-09 | ||
| JP63316515A JPH02164603A (en) | 1988-12-16 | 1988-12-16 | Radial tire for heavy load |
| JP63-316,515 | 1988-12-16 | ||
| JP63319634A JP2718968B2 (en) | 1988-12-20 | 1988-12-20 | Radial tire for high internal pressure and heavy load |
| JP63-319,634 | 1988-12-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2000945A1 true CA2000945A1 (en) | 1990-04-24 |
Family
ID=27478763
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2000945 Abandoned CA2000945A1 (en) | 1988-10-24 | 1989-10-18 | Heavy duty pneumatic radial tires used under high internal pressure |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA2000945A1 (en) |
| FR (1) | FR2638125A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105517816A (en) * | 2013-08-28 | 2016-04-20 | 株式会社普利司通 | Heavy duty pneumatic tire |
| CN111094019A (en) * | 2017-10-30 | 2020-05-01 | 米其林集团总公司 | Heavy truck tire tread and heavy truck tire |
| CN112135740A (en) * | 2018-05-24 | 2020-12-25 | 米其林集团总公司 | Heavy truck tire tread and heavy truck tire with sloped and angled shoulder grooves |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60240507A (en) * | 1984-05-15 | 1985-11-29 | Sumitomo Rubber Ind Ltd | Low noise multi-siping tire |
| JPH07115571B2 (en) * | 1986-04-22 | 1995-12-13 | 横浜ゴム株式会社 | Pneumatic radial tires for heavy loads |
| JPS63106113A (en) * | 1986-06-09 | 1988-05-11 | Bridgestone Corp | Pneumatic radial tyre for heavy load |
| JPS63149205A (en) * | 1986-12-10 | 1988-06-22 | Bridgestone Corp | Pneumatic radial tire |
-
1989
- 1989-10-18 CA CA 2000945 patent/CA2000945A1/en not_active Abandoned
- 1989-10-24 FR FR8913944A patent/FR2638125A1/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105517816A (en) * | 2013-08-28 | 2016-04-20 | 株式会社普利司通 | Heavy duty pneumatic tire |
| US10000094B2 (en) | 2013-08-28 | 2018-06-19 | Bridgestone Corporation | Heavy duty pneumatic tire |
| CN111094019A (en) * | 2017-10-30 | 2020-05-01 | 米其林集团总公司 | Heavy truck tire tread and heavy truck tire |
| EP3703959B1 (en) * | 2017-10-30 | 2023-07-19 | Compagnie Générale des Etablissements Michelin | Heavy truck tire tread and heavy truck tire |
| CN112135740A (en) * | 2018-05-24 | 2020-12-25 | 米其林集团总公司 | Heavy truck tire tread and heavy truck tire with sloped and angled shoulder grooves |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2638125A1 (en) | 1990-04-27 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |