CN110001307B - Pneumatic radial tire for heavy load - Google Patents
Pneumatic radial tire for heavy load Download PDFInfo
- Publication number
- CN110001307B CN110001307B CN201811493007.6A CN201811493007A CN110001307B CN 110001307 B CN110001307 B CN 110001307B CN 201811493007 A CN201811493007 A CN 201811493007A CN 110001307 B CN110001307 B CN 110001307B
- Authority
- CN
- China
- Prior art keywords
- tire
- chafer
- bead
- bead core
- wire chafer
- 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.)
- Active
Links
Images
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
- B60C15/00—Tyre beads, e.g. ply turn-up or overlap
- B60C15/04—Bead cores
-
- 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
- B60C15/00—Tyre beads, e.g. ply turn-up or overlap
- B60C15/06—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Tires In General (AREA)
Abstract
The invention provides a heavy load pneumatic radial tire. The technical problem is as follows: the invention realizes cost reduction and improvement of rim assembly performance without reducing the tire bead durability of a tire. The solution is as follows: the tire (T) is characterized in that the wire chafer (6) is arranged only on the outer surface side of the tire, the lower end (6E) of the wire chafer (6) is arranged between the center and the upper end of the bead core (11) in the radial direction of the tire, and the organic fiber chafer (7), the wire chafer (6) and the carcass ply (4) are arranged in this order from the outer surface side of the tire.
Description
Technical Field
The present invention relates to a heavy duty pneumatic radial tire characterized by a bead structure.
Background
Currently, in a heavy load pneumatic radial tire, a structure is generally such that a wire chafer for bead reinforcement is wound up to the tire inner surface side, and as shown in the following patent documents for a heavy load pneumatic radial tire, a structure is such that a wire chafer for bead reinforcement is disposed from a side portion position of a bead core to the tire radial direction outer side along a carcass ply on the tire outer surface side.
Patent document 1 discloses a heavy load pneumatic radial tire having a structure in which a bead portion is not broken down even under a long-term running condition of a tread, while maintaining a light weight and a low cost of the bead portion required in a market place, with respect to a tire for a medium/large truck, a bus, and a tractor/trailer.
That is, the heavy load pneumatic radial tire includes: the pneumatic radial tire for heavy load comprises a bead reinforcing layer formed by arranging one or more fiber cord layers substantially along the outer surface of the radial carcass around the bead core in a range from the whole of the bead seat side range surrounded by a perpendicular line passing through the maximum width position of the cross section of the bead core and directed toward the tire rotation axis to the maximum diameter position of the cross section of the bead core.
Patent document 2 below discloses a heavy load pneumatic radial tire having the following structure, and an object of the present invention is to provide a heavy load pneumatic radial tire in which separation at a turnup end is less likely to occur and which has excellent durability.
Specifically, the pneumatic radial tire for heavy load comprises at least one carcass ply having a carcass ply arranged so as to be bridged between a pair of bead portions and a turn-up ply turned up from the inside to the outside around a bead core provided in the bead portion and a rubber filler arranged on the outer circumferential side of the bead core and locked, and the pneumatic radial tire for heavy load comprises a covering rubber covering an end of the turn-up ply and soft rubber pads softer than the covering rubber and covering both sides of the covering rubber in the tire width direction, wherein the distance between a normal line drawn from the outer circumferential side end of a rim flange when a predetermined rim is assembled from the outer circumferential side surface of the carcass ply and the end of the turn-up ply is less than 15 mm. Further, the soft rubber pad includes, on the outer side in the tire width direction, a steel cord reinforcing layer disposed on the outer peripheral side end of the tire further toward the outer side in the tire radial direction than the end of the turning-up carcass layer.
Patent document 3 below discloses a heavy duty radial tire having the following configuration for the purpose of minimizing deformation strain at the upper end of a folded portion of a carcass in a bead portion.
That is, the radial tire for heavy load has a pair of left and right bead cores, a carcass ply constituted by arranging steel cords folded back around the bead cores from the inside to the outside in the radial direction, a belt layer constituted by arranging the cords at a small angle with respect to the tire equator outside the crown portion of the carcass ply, and a reinforcing layer of steel cords disposed adjacently outside the folded back portion of the carcass ply.
That is, in the pneumatic radial tire for heavy load in which a bead core having a substantially triangular shape as a whole, which is composed of a high-hardness filler base having a substantially triangular cross section and a low-hardness filler pad adjacent to the outside thereof and longer than the high-hardness filler base, is filled from a portion surrounded by the carcass ply, the folded portion thereof, and the steel cord reinforcement layer, to a sidewall portion, in the vicinity of the upper end of the steel cord reinforcing layer, a fin-shaped intermediate pad having a medium hardness is disposed so as to be adjacent to the outside of the low-hardness filler pad toward the upper side, an organic fiber reinforcing layer is disposed so as to be adjacent to the outside of the steel cord reinforcing layer, the organic fiber reinforcing layer is disposed over the height of the tip of the steel cord reinforcing layer from below the region where the lower end of the carcass ply is located and over the region of the intermediate pad having a medium hardness, and a side pad having a medium hardness is disposed further outside the organic fiber reinforcing layer, thereby improving bead durability.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open publication No. 5-112109
Patent document 2: japanese patent laid-open No. 2006-15951
Patent document 3: japanese patent laid-open publication No. Showa 60-157905
Patent document 4: japanese patent laid-open publication No. Hei 7-117419
Disclosure of Invention
Technical problem to be solved
However, in the above-described conventional technique, a technique including a means for improving the rim mountability is not disclosed.
The present invention has been made in view of the above points, and aims to reduce the cost and improve the rim attachment performance without reducing the bead durability of a tire.
(II) technical scheme
The pneumatic radial tire for heavy load of the present invention comprises a bead core embedded in a bead portion, a bead filler arranged on the outer side in the tire radial direction of the bead core, and a carcass ply turned up from the inner side to the outer side in the tire width direction around the bead core so as to sandwich the bead filler, and is characterized by comprising one or more wire chafers and one or more organic fiber chafers as a bead reinforcing layer, the organic fiber chafers being turned up from the tire inner surface side to the tire outer surface side around the bead core, the wire chafers being arranged only on the tire outer surface side, the lower end of the wire chafer being arranged between the center and the upper end in the tire radial direction of the bead core, the organic fiber chafer, the wire chafer being arranged in this order from the tire outer surface side, A carcass ply.
As described above, in the present invention, the wire chafer structure is disposed only on the outer surface side (the turned-up side) of the tire, and is not disposed below the bead core and on the inner surface side, so that it is possible to improve the deterioration of the rim fitting property caused by disposing the wire chafer below the bead core in the related art.
Further, as described above, since the lower end of the wire chafer in the present invention is disposed between the center and the upper end of the bead core in the tire radial direction, in the case of an inner type tire, the thickness of the bead core on the outer circumferential side of the tire is reduced, and the durability of the bead portion is improved. In this regard, unlike the structures of the heavy load pneumatic radial tires described in patent documents 1 to 4, the operational effects thereof are different.
In addition to the above-described structure, the heavy load pneumatic radial tire according to the present invention may be structured such that the end of the wire chafer on the radially inner side is 20mm or more from the carcass ply turn-up end.
In the case of such a configuration, the ply turn-up end and the wire chafer end are separated, whereby strain concentration can be avoided.
In addition to the above-described respective configurations, the heavy-duty pneumatic radial tire according to the present invention may be configured such that the radially inner end of the wire chafer is disposed radially inward of a normal line from the center point of the radius of curvature of the rim flange to the straight portion of the turned-up portion of the carcass ply radially outward of the upper surface of the bead core.
In the case of such a configuration, even if the rim flange sinks into the bead due to tire deformation when a load is applied, the radial shear strain occurring at this time can be reduced.
In addition to the above-described respective configurations, the heavy load pneumatic radial tire according to the present invention may be configured such that the turned-up end of the carcass ply is located further toward the tire radial direction inner side than the upper end of the wire chafer, and the upper end of the wire chafer is located further toward the tire radial direction inner side than the turned-up end of the organic fiber chafer.
This point is different from the heavy load pneumatic radial tires described in patent documents 1 and 3.
In addition to the above-described structure, the heavy load pneumatic radial tire according to the present invention may be a tube-type pneumatic tire.
In general, in the case of a heavy-duty tubeless tire, the tire has a rim shape with a taper angle of 15 ° in order to prevent bead crossing due to high internal pressure filling. However, a heavy-duty tube tire generally has a rim shape with a 5 ° cone angle different from that of the heavy-duty tube tire. Therefore, if the structure of the present invention is adopted for a tube tire as described above, the rim attachment performance can be improved.
(III) advantageous effects
The heavy load pneumatic radial tire of the present invention is configured such that the wire chafer is disposed only on the outer surface side of the tire and the wire chafer end is disposed between the center and the upper end of the bead core in the tire radial direction, whereby the amount of the wire chafer used can be reduced to reduce the cost without deteriorating the bead durability of the tire, and the rubber thickness below the carcass ply can be secured, thereby enabling the rim fittability to be improved.
Drawings
Fig. 1 is a radial cross-sectional view of a tire showing an example of a heavy duty pneumatic radial tire according to the present invention.
Fig. 2 is an enlarged cross-sectional view of a bead portion of the tire of fig. 1.
Description of the reference numerals
T-tire; Rim-Rim flange; r-center point of radius of curvature of rim flange; l-a normal line drawn to a linear portion of the turn-up portion of the carcass ply; 1-a bead portion; 11-a bead core; 12-bead filler; 2-sidewall portions; 3-a tread portion; 4-a carcass ply; 41-main body portion of carcass ply; 42-the turn-up of the carcass ply; 4E-the turnup end of the carcass ply; 121-a first bead core; 121E-the upper end of the first bead core; 122-a second bead filler; 6-wire chafer; 61E-lower end of wire chafer; 62E-upper end of wire chafer; 7-organic fiber chafer; 71- -inner side of organic fiber chafer; 71E-inner end of organic fiber chafer; 72-an outer side of the organic fiber chafer; 72E-the turn-up end of the organic fiber chafer; 8-a reinforcing rubber layer; h-the spacing between the lower end of the wire chafer and the turned-up end of the carcass ply; e-a line segment representing the upper end position of the bead core; c-a line segment representing the tire radial direction center position of the bead core.
Detailed Description
Embodiments of the present invention will be described below with reference to the drawings.
Fig. 1 shows an example of a heavy duty pneumatic radial tire (hereinafter, simply referred to as "tire") T according to the present invention, which is a tire radial cross section in assembling a standard rim. The standard Rim fitting is a state in which the tire T is fitted to a Rim defined by JATMA corresponding to the tire size and is filled with air having an air pressure of 50 kPa. Fig. 2 is an enlarged cross-sectional view of the bead portion 1 of the tire T.
As shown in fig. 1, the tire T includes a pair of bead portions 1, a sidewall portion 2 extending outward in the tire radial direction from the bead portions 1, and a tread portion 3 connected to an outer end of the sidewall portion 2 in the tire radial direction. A bead core 11 is embedded in the bead portion 1, and a bead filler 12 is disposed on the outer side of the bead core 11 in the tire radial direction.
The tire T further includes a carcass ply 4, and the carcass ply 4 reaches the bead portion 1 from the tread portion 3 via the sidewall portion 2 and is turned up around the bead core 11 from the inner side to the outer side in the tire width direction so as to sandwich the bead filler 12.
The bead core 11 is formed of a bunch of wires wound in layers with rubber, and is formed annularly along the tire circumferential direction. The bead filler 12 has a tapered shape toward the tire radial direction outer side, and the leading end thereof is disposed further toward the tire radial direction outer side than the turned-up end 4E of the carcass ply 4.
The bead filler 12 is composed of a first bead filler 121 disposed in contact with the bead core 11, and a second bead filler 122 disposed on the outer side of the first bead filler 121 in the tire width direction. The first bead core 121 has a substantially triangular cross section extending outward in the tire radial direction, the second bead core 122 is disposed adjacent to the outer side of the first bead core 121, and the bead core 12 has a substantially triangular cross section extending outward in the tire radial direction as a whole. The first bead core 121 is harder than the second bead core 122. For example, the rubber hardness of the first bead core 121 is 110 or more, and the rubber hardness of the second bead core 122 is 100 or less. Further, the rubber hardness in the present invention is JIS K6253-1-20123.2 durometer hardness (durometer hardness).
The carcass ply 4 is provided with a turn-up portion 42 disposed on the outer side in the tire width direction of the bead core 11 and the bead filler 12 continuously from the tread portion 3 to the main body portion 41 of the bead portion 1 via the sidewall portion 2. The rolled end 4E is an end of the rolled portion 42. The carcass ply 4 is formed by coating a plurality of carcass cords aligned in a direction substantially perpendicular to the tire circumferential direction with rubber. As the material of the carcass cord, metal such as steel wire, organic fiber such as polyester, rayon, nylon, and aramid are suitably used.
Further, the tire T includes a wire chafer 6 including a steel cord. The wire chafer 6 is disposed only on the tire outer surface side, and the wire chafer 6 is disposed such that the radial inner end 61E, which is the lower end of the wire chafer 6, is located between the tire radial direction center and the upper end of the bead core 11, that is, between the tire radial direction center of the bead core 11 indicated by the line segment c and the upper end indicated by the line segment E.
In general, since the rigidity of the bead core and the wire chafer is high, if the lower end of the wire chafer is located above the upper end of the bead core when manufacturing or when an internal pressure is applied to the tire during a tire load, the thickness of the rubber portion located on the outer side in the tire width direction from the bead core toward the outer side in the tire width direction is reduced, and the force is applied in the direction in which the wire chafer moves to the outer side in the tire radial direction, which makes it difficult to control. However, if the lower end 61E of the wire chafer 6 is positioned between the center and the upper end of the bead core 11 in the tire radial direction as in the present invention, even when an internal pressure is applied to the tire, the wire chafer 6 is sandwiched between the bead cores 11 to be in a stable state, and therefore, the positions of the respective members around which the wire chafer 6 is wound are stable, and there is an effect that stable quality manufacturing is possible and the durability of the bead portion 1 is increased. In addition, if the lower end of the wire chafer is located downward with respect to the tire radial direction center of the bead core 11, the durability is lowered.
62E is the turned-up end of the wire chafer 6, i.e., the upper end as the radially outer end.
The distance H between the lower end 61E of the wire chafer 6 and the turned-up end 4E of the carcass ply 4 is 20mm or more.
The radially inner end 61E of the wire chafer 6 is disposed radially inward of a normal line L from the center point R of the radius of curvature of the Rim flange Rim to the straight portion of the turned-up portion 42 of the carcass ply 4 radially outward of the upper surface of the bead core 11. With this configuration, even if the Rim flange Rim sinks into the bead portion 1 due to deformation of the tire T when a load is applied, the radial shear strain generated at this time can be reduced. Further, in the present invention, the wire chafer 6 is disposed so that the radial inner end 61E, which is the lower end of the wire chafer 6, is positioned between the tire radial direction center of the bead core 11 and the upper end, that is, between the tire radial direction center of the bead core 11 indicated by the line segment c and the upper end indicated by the line segment E, and therefore, the radial shear strain caused by the deformation of the tire T when a load is applied is further reduced.
Further, the radially inner wire chafer end 61E of the wire chafer 6 may be disposed radially inward from a height 0.8 times the height of the Rim flange Rim. In the case of such a configuration, even if the Rim flange Rim sinks into the bead portion 1 due to deformation of the tire T when a load is applied, the radial shear strain generated at this time can be further reduced.
The wire chafer 6 is formed by coating a plurality of steel cords arranged in a direction inclined with respect to the tire radial direction with rubber. The plurality of steel cords are arranged in parallel with each other, and an inclination angle with respect to the tire radial direction is set to, for example, 50 to 80 °. The wire chafer 6 is joined to the carcass ply 4 from the outside so as to cover the carcass ply 4. The number of ends of the steel cord (the number of cords per inch in the cord width direction) is preferably 10/foot or more, and the cord diameter of the steel cord is preferably 0.9mm or more.
Further, the tire T has an organic fiber chafer 7 including an organic fiber cord. The organic fiber chafer 7 is disposed along the outer side of the wire chafer 6 only at the portion located at the outer side in the tire width direction thereof, and is rolled up around the bead core 11 from the inner side to the outer side in the tire width direction as a whole. That is, the organic fiber chafer 7 is provided with an outer portion (corresponding to a turned-up portion of the organic fiber chafer 7) 72 located on the outer side in the tire width direction of the wire chafer 6 continuously at an inner portion 71 located on the inner side in the tire width direction of the carcass ply main body portion 41. The inner end 71E is an end of the organic fiber chafer 7 (inner end 71) located on the inner side in the tire width direction, and the turn-up end 72E (corresponding to the outer end of the organic fiber chafer 7) is an end of the organic fiber chafer 7 (outer end 72) located on the outer side in the tire width direction.
The organic fiber chafer 7 is formed by coating a plurality of organic fiber cords arranged in a direction inclined with respect to the tire radial direction with rubber. The plurality of organic fiber cords are arranged in parallel with each other, and an inclination angle with respect to the tire radial direction is set to 30 to 60 degrees, for example. Examples of the material of the organic fiber cord include nylon, polyester, rayon, and aramid. The organic fiber chafer 7 is in contact with the wire chafer 6 from the outside in such a manner that the outer side portion 72 thereof wraps the wire chafer 6. The number of ends of the organic fiber cord is preferably 15/ft or more, and the cord diameter of the organic fiber cord is preferably 0.4mm or more.
The reinforcing rubber layer 8 is provided on the tire width direction outer side of the second bead filler 122 so as to sandwich the upper end 62E of the wire chafer 6 and the turned-up end 72E of the organic fiber chafer 7 from both sides in the tire width direction. The reinforcing rubber layer 8 is disposed adjacent to the tire width direction outer side of the second bead filler 122. The turned-up end 4E of the carcass ply 4 is sandwiched by the second bead filler 122 and the reinforcing rubber layer 8.
The upper end 121E of the first bead core 121 is disposed further inward in the tire radial direction than the upper end 62E of the wire chafer 6. The turned-up end 4E of the carcass ply 4 is disposed further inward in the tire radial direction than the upper end 62E of the wire chafer 6.
The turn-up end 72E of the organic fiber chafer 7 is disposed further outward in the tire radial direction than the upper end 62E of the wire chafer 6.
Therefore, the organic fiber chafer 7, the wire chafer 6, and the carcass ply 4 are configured such that the organic fiber chafer 7, the wire chafer 6, and the carcass ply 4 are arranged in this order from the outer surface side of the tire, the turned-up end 4E of the carcass ply 4 is located further toward the tire radial direction inner side than the upper end 62E of the wire chafer 6, and the upper end 62E of the wire chafer is located further toward the tire radial direction inner side than the organic fiber chafer turned-up end 72E.
With the wire chafer 6 having the end portion arranged as described above, it is possible to suppress a failure such as separation starting from the turned-up end 4E of the carcass ply 4. Further, the organic fiber chafer 7 having the end portion arranged as described above can suppress a failure such as separation starting from the lower end 61E and the upper end 62E of the wire chafer 6.
The organic fiber chafer 7 is preferably composed of at least two layers, and the organic fiber chafer 7 of the present embodiment is composed of two organic fiber cords which are overlapped so as to be inclined in opposite directions to each other with respect to the tire radial direction. The positional relationship of the end portions of the organic fiber chafer described above may be satisfied by at least one of the plurality of layers constituting the organic fiber chafer, and preferably by all the layers as in the present embodiment.
The tire of the present invention can be used in the present invention with any conventionally known materials, shapes, structures, manufacturing methods, and the like, as in the case of a normal pneumatic radial tire, except that the bead portion is configured as described above. The bead structure as described above may be applied to at least one bead portion, and is preferably applied to both bead portions.
The tire of the present invention has a structure in which the wire chafer is disposed only on the outer surface side (the turn-up side) of the tire, and is not disposed below the bead core and on the inner surface side, so that the rim fitting property can be improved, and is disposed between the center in the tire radial direction of the bead core and the upper end, so that in the case of an inner tire type tire, the thickness of the outer circumferential side of the bead core becomes small and the durability of the bead portion is improved, and therefore, the tire is particularly suitable for a heavy load pneumatic radial tire with an inner tube.
Examples
In order to specifically show the structure and effects of the present invention, a durability test and a rim assembling property improvement test of a bead portion are performed, and the following description is given. The tire for testing was 11.00R20 in size, fitted on an 8.00V rim.
In the durability test, the tire was run on a drum having a diameter of 1700mm under conditions of an internal pressure of 830kPa, a load of 32.9kN (10% increase per 24 hours), and a speed of 25km/h until a failure occurred in the bead portion. Then, the running distance was evaluated by an index obtained when the result of comparative example 1 was 100. In addition, with respect to the tire after the test running, the presence or absence of the crack at the turned-up end of the wire chafer and the turned-up end of the carcass ply was confirmed (a result of progress of separation).
In the rim fittability improvement test, the case where the tire could be fitted to the rim by the weight of the tire alone without assistance was evaluated as improved, the case where the tire could be fitted to the rim if assistance was applied was evaluated as not improved, and the case where the tire could not be fitted to the rim even if assistance was applied was evaluated as deteriorated.
The above tests were carried out for the following examples 1 and 2 and comparative examples 1 to 3, and the results are summarized in table 1.
[ example 1 ]
In the tire of example 1, the wire chafer was fitted only on the tire outer surface side radially outward with respect to the bottom surface of the bead core.
The wire chafer is assembled in such a manner that the lower end of the wire chafer is located between the tire radial direction center of the bead core and the upper end.
Further, the end of the wire chafer on the radially inner side is 30mm from the carcass ply turn-up end.
The radially inner end of the wire chafer is disposed radially outward, i.e., above a normal line from a center point of a curvature radius of the rim flange to a linear portion of the turned-up portion of the carcass ply radially outward of the upper surface of the bead core.
[ example 2 ]
In the tire of example 2, the wire chafer was fitted only on the tire outer surface side radially outward with respect to the bottom surface of the bead core.
The wire chafer is assembled in such a manner that the lower end of the wire chafer is located between the tire radial direction center of the bead core and the upper end.
Further, the end of the wire chafer on the radially inner side is 35mm from the carcass ply turn-up end.
The radially inner end of the wire chafer is disposed radially inward, that is, below a normal line from a center point of a curvature radius of the rim flange to a linear portion of the turned-up portion of the carcass ply radially outward of the upper surface of the bead core.
Comparative example 1
In the tire of comparative example 1, the structure was such that the wire chafer was wound up to the tire inner surface side.
Comparative example 2
In the tire of comparative example 2, the wire chafer was fitted only on the tire outer surface side radially outward with respect to the bottom surface of the bead core.
The wire chafer is assembled in such a manner that the lower end of the wire chafer is located between the tire radial direction center of the bead core and the lower end.
Further, the end of the wire chafer on the radially inner side is 45mm from the carcass ply turn-up end.
The radially inner end of the wire chafer is disposed radially inward, that is, below a normal line from a center point of a curvature radius of the rim flange to a linear portion of the turned-up portion of the carcass ply radially outward of the upper surface of the bead core.
Comparative example 3
In the tire of comparative example 3, the wire chafer was fitted only on the tire outer surface side radially outward with respect to the bottom surface of the bead core.
The wire chafer is assembled in such a manner that the lower end of the wire chafer is located above with respect to the tire radial direction upper end of the bead core.
Further, the end of the wire chafer on the radially inner side is 15mm from the turned-up end of the carcass ply.
The radially inner end of the wire chafer is disposed radially outward, i.e., above a normal line from a center point of a curvature radius of the rim flange to a linear portion of the turned-up portion of the carcass ply radially outward of the upper surface of the bead core.
Further, with regard to the tire of the size 11.00R20 for testing, if the wire chafer is disposed radially outward with respect to the bottom surface of the bead core such that the lower end of the wire chafer is located between the tire radial center and the upper end of the bead core, it inevitably results in the end of the radially inner side of the wire chafer being 20mm or more from the carcass ply turn-up end, and therefore a comparative example cannot be made in which the wire chafer is located radially outward with respect to the bottom surface of the bead core and the lower end of the wire chafer is located between the tire radial center and the upper end of the bead core and less than 20mm from the carcass ply turn-up end. In this tire, as a result, the radially inner end of the wire chafer is located in the widest range of 20mm or more from the turned-up end of the carcass ply, and then, in the range from the center of the bead core in the tire radial direction to the upper end, again, in the range further radially inward than the normal line from the center point of the radius of curvature of the rim flange to the linear portion of the turned-up portion of the carcass ply further radially outward than the upper surface of the bead core.
[ TABLE 1 ]
And (2) evaluating the rim assembly property: the tire can be mounted on the rim by only the weight of the tire without assistance.
Δ if force is applied to assist, the tire can be mounted on the rim.
X the tire cannot be mounted on the rim even with the assistance of force.
As shown in table 1, comparative example 1 is the same as comparative example 2 in terms of bead durability, but since a structure in which a wire chafer is wound up to the tire inner surface side is adopted, rim fittability is not improved. The other examples 1 and 2, and comparative examples 2 and 3 all improve the rim fittability because the wire chafers are disposed on the tire outer surface side radially outward with respect to the bottom surface of the bead core.
Therefore, the degree of bead durability reduction was confirmed for examples 1 and 2, and comparative examples 2 and 3.
In comparative example 2, the radially inner end of the wire chafer was 45mm from the turned-up end of the carcass ply, and was disposed radially inward, i.e., below the normal line from the center point of the radius of curvature of the rim flange to the linear portion of the turned-up portion of the carcass ply radially outward of the upper surface of the bead core, but was disposed so as to be located between the center and the lower end of the bead core in the tire radial direction, and therefore, a crack occurred at the end of the wire protective layer and a crack occurred at the end of the carcass ply at a running distance index of 100.
In comparative example 3, the radially inner end of the wire chafer was disposed so as to be located above the tire radial direction upper end of the bead core, and was located only 15mm from the carcass ply turnup end, and was disposed further radially outward, i.e., on the upper side, than the normal line from the center point of the radius of curvature of the rim flange to the linear portion of the turned-up portion of the carcass ply further radially outward than the upper surface of the bead core, and therefore, a crack occurred at the carcass ply end and a failure occurred at another (rim flange contact portion) position at the running distance index of 110.
In example 1, the radially inner end of the wire chafer was disposed radially outward, i.e., above the normal line from the center point of the radius of curvature of the rim flange to the straight portion of the turned-up portion of the carcass ply radially outward of the upper surface of the bead core, but since the wire chafer was disposed so as to be positioned between the tire radial direction center of the bead core and the upper end and the distance from the turned-up end of the carcass ply was 30mm, only a failure at the other (rim flange contact portion) position occurred at the running distance index 130.
In example 2, the radially inner end of the wire chafer was disposed so as to be positioned between the tire radial direction center and the upper end of the bead core, and was 35mm away from the carcass ply turn-up end, and was disposed further radially inward, i.e., lower than the normal line from the center point of the radius of curvature of the rim flange to the linear portion of the turn-up portion of the carcass ply further radially outward than the upper surface of the bead core, and therefore, only the crack at the end of the carcass ply occurred at the running distance index 140.
As a result of the above, if the radially inner end of the wire chafer is disposed so as to be positioned between the center and the upper end of the bead core in the tire radial direction, the durability of the entire bead portion is improved, if the end is spaced from the turned-up end of the carcass ply by about 30mm, the durability of the carcass ply end of the bead portion is improved, and if the end is disposed so as to be positioned further inward in the radial direction, that is, further downward than the normal line from the center point of the radius of curvature of the rim flange to the linear portion of the turned-up portion of the carcass ply further outward in the radial direction than the upper surface of the bead core, the durability of the flange portion is improved.
From the above results, it can be said that examples 1 and 2 can improve the rim assembling property without lowering the bead durability as compared with comparative examples 1 to 3.
While the embodiments of the present invention have been described above, these embodiments are presented as examples and do not limit the scope of the invention. These embodiments can be implemented in other various ways, and various omissions, substitutions, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope of the invention, and are also included in the invention described in the patent claims and the equivalent scope thereof.
Claims (5)
1. A pneumatic radial tire for heavy load comprising a bead core embedded in a bead portion, a bead filler arranged on the outer side in the tire radial direction of the bead core, and a carcass ply turned up around the bead core from the inner side to the outer side in the tire width direction so as to sandwich the bead filler, characterized in that,
the bead reinforcement layer comprises at least one wire chafer and at least one organic fiber chafer,
the organic fiber chafer is turned up around the bead core from the tire inner surface side to the tire outer surface side,
the wire chafer is disposed only on the outer surface side of the tire,
the lower end of the wire chafer is disposed between the tire radial direction center of the bead core and the upper end,
the distance from the radially inner end of the wire chafer to the turned-up end of the carcass ply is 20mm to 35mm,
an organic fiber chafer, a wire chafer, and a carcass ply are arranged in this order from the outer surface side of the tire.
2. The heavy-duty pneumatic radial tire according to claim 1,
the radially inner end of the wire chafer is disposed radially inward of a normal line from a center point of a curvature radius of the rim flange to a straight line portion of the turned-up portion of the carcass ply radially outward of the upper surface of the bead core.
3. The heavy-duty pneumatic radial tire according to claim 1 or 2,
the turned-up end of the carcass ply is located further toward the tire radial inner side than the upper end of the wire chafer, and the upper end of the wire chafer is located further toward the tire radial inner side than the turned-up end of the organic fiber chafer.
4. The heavy-duty pneumatic radial tire according to claim 1 or 2,
the pneumatic tire is a tube tire.
5. The heavy-duty pneumatic radial tire according to claim 3,
the pneumatic tire is a tube tire.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2017245707A JP6989374B2 (en) | 2017-12-22 | 2017-12-22 | Pneumatic radial tires for heavy loads |
| JP2017-245707 | 2017-12-22 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110001307A CN110001307A (en) | 2019-07-12 |
| CN110001307B true CN110001307B (en) | 2021-01-29 |
Family
ID=67165075
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811493007.6A Active CN110001307B (en) | 2017-12-22 | 2018-12-07 | Pneumatic radial tire for heavy load |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP6989374B2 (en) |
| CN (1) | CN110001307B (en) |
Family Cites Families (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS53121304A (en) * | 1977-03-31 | 1978-10-23 | Bridgestone Corp | Arrangement for strengthening head section of heavy-duty pneumatic radial type |
| JPS6357305A (en) * | 1986-08-28 | 1988-03-12 | Bridgestone Corp | Heavy duty pneumatic radial tire having carcass ply made of aromatic polyamide fiber cord |
| JPH0367710A (en) * | 1989-08-08 | 1991-03-22 | Bridgestone Corp | Heavy duty pneumatic tire |
| JPH0411506A (en) * | 1990-04-30 | 1992-01-16 | Sumitomo Rubber Ind Ltd | Heavy-load radial tire |
| JPH11151919A (en) * | 1997-11-21 | 1999-06-08 | Bridgestone Corp | Pneumatic radial tire for heavy load and manufacture thereof |
| JP3733029B2 (en) * | 2001-01-11 | 2006-01-11 | 住友ゴム工業株式会社 | Pneumatic tire |
| JP3966799B2 (en) * | 2002-10-30 | 2007-08-29 | 横浜ゴム株式会社 | Pneumatic tire |
| JP2004306631A (en) * | 2003-04-02 | 2004-11-04 | Bridgestone Corp | Pneumatic radial tire for heavy load |
| JP4307226B2 (en) * | 2003-12-03 | 2009-08-05 | 株式会社ブリヂストン | Pneumatic tire |
| JP4500117B2 (en) * | 2004-07-05 | 2010-07-14 | 東洋ゴム工業株式会社 | Heavy duty pneumatic radial tire |
| WO2006082869A1 (en) * | 2005-02-02 | 2006-08-10 | Bridgestone Corporation | Pneumatic tire |
| JP2007045354A (en) * | 2005-08-11 | 2007-02-22 | Bridgestone Corp | Pneumatic tire |
| FR2935297B1 (en) * | 2008-09-02 | 2010-09-03 | Michelin Soc Tech | TIRE FOR HEAVY VEHICLES COMPRISING AT LEAST TWO ADDITIONAL LAYERS IN THE BOURRELETS |
| JP6022841B2 (en) * | 2012-07-25 | 2016-11-09 | 東洋ゴム工業株式会社 | Pneumatic radial tire |
| JP5475096B1 (en) * | 2012-12-10 | 2014-04-16 | 東洋ゴム工業株式会社 | Pneumatic radial tire |
| JP5858069B2 (en) * | 2014-03-06 | 2016-02-10 | 横浜ゴム株式会社 | Pneumatic tire |
| JP6245011B2 (en) * | 2014-03-19 | 2017-12-13 | 横浜ゴム株式会社 | Pneumatic radial tire |
| JP6577345B2 (en) * | 2015-11-18 | 2019-09-18 | 株式会社ブリヂストン | Pneumatic tire |
-
2017
- 2017-12-22 JP JP2017245707A patent/JP6989374B2/en active Active
-
2018
- 2018-12-07 CN CN201811493007.6A patent/CN110001307B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| JP6989374B2 (en) | 2022-01-05 |
| CN110001307A (en) | 2019-07-12 |
| JP2019111885A (en) | 2019-07-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP6249518B2 (en) | Pneumatic tire | |
| US8905102B2 (en) | Pneumatic radial tire with round crosssection lower filler surrounding bead core | |
| JP4046502B2 (en) | Pneumatic radial tire | |
| CN1796163A (en) | Pneumatic tire with high turnup, locked bead construction | |
| EP3189987B1 (en) | Pneumatic tire | |
| ZA200903808B (en) | Performance tire with sidewall insert | |
| JP6521451B2 (en) | Pneumatic tire | |
| JP2009001073A (en) | Pneumatic radial tire | |
| JP2002500121A (en) | Tire bead with circumferential reinforcement element | |
| JP6497778B2 (en) | Pneumatic tire | |
| US9073389B2 (en) | All steel fabric radial construction for agricultural tires | |
| EP3798027B1 (en) | Tire with improved bead portion | |
| CN110001307B (en) | Pneumatic radial tire for heavy load | |
| JP3808595B2 (en) | Heavy duty pneumatic radial tire | |
| JP6315651B2 (en) | Pneumatic tire | |
| US20100065184A1 (en) | Reinforcing structure for pneumatic tires | |
| JP6801488B2 (en) | Pneumatic tires | |
| US20100065183A1 (en) | Turnup reinforcing structure for pneumatic tires | |
| JP2009090974A (en) | Pneumatic tire | |
| CN109927491B (en) | Pneumatic radial tire for heavy load | |
| JP6766451B2 (en) | Pneumatic tires | |
| JP2001146105A (en) | Pneumatic tire | |
| JP2019107950A (en) | Pneumatic radial tire for heavy load | |
| JP6334932B2 (en) | Pneumatic tire | |
| JP7238231B2 (en) | pneumatic tire |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |