CA1116502A - Radial carcass tire - Google Patents
Radial carcass tireInfo
- Publication number
- CA1116502A CA1116502A CA000340574A CA340574A CA1116502A CA 1116502 A CA1116502 A CA 1116502A CA 000340574 A CA000340574 A CA 000340574A CA 340574 A CA340574 A CA 340574A CA 1116502 A CA1116502 A CA 1116502A
- Authority
- CA
- Canada
- Prior art keywords
- tire
- radial carcass
- axis
- carcass reinforcement
- beta
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000011324 bead Substances 0.000 claims abstract description 42
- 230000002787 reinforcement Effects 0.000 claims abstract description 40
- 239000000835 fiber Substances 0.000 claims abstract description 10
- 230000007935 neutral effect Effects 0.000 claims abstract description 10
- 230000000694 effects Effects 0.000 claims abstract description 4
- 230000000875 corresponding effect Effects 0.000 claims 1
- 229910000831 Steel Inorganic materials 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
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
- B60C3/00—Tyres characterised by the transverse section
- B60C3/04—Tyres characterised by the transverse section characterised by the relative dimensions of the section, e.g. low profile
-
- 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
- B60C9/02—Carcasses
- B60C9/04—Carcasses the reinforcing cords of each carcass ply arranged in a substantially parallel relationship
- B60C9/08—Carcasses the reinforcing cords of each carcass ply arranged in a substantially parallel relationship the cords extend transversely from bead to bead, i.e. radial ply
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Tires In General (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A tubeless tire with radial carcass reinforcement for a vehicle wheel whose rim has bead seats with an angle of inclination of about 15° is characterized by the fact that when this tire is mounted and inflated, but not under load, the neutral or mean meridian fiber of its radial carcass re-inforcement follows, between the points of tangency of the radial carcass reinforcement with the bead ring and with the tread reinforcement, the natural equilibrium profile such that cos ? = , the quantity (Rs12 - Re12) being equal to about k (RSo2 - Reo2), Po being the rated inflation pressure and P1 the inflation pressure such that the tire retains its rated deflection under the effect of an overload, k being a positive coefficient between 1 and the value of the ratio , and sin .beta.1=
A tubeless tire with radial carcass reinforcement for a vehicle wheel whose rim has bead seats with an angle of inclination of about 15° is characterized by the fact that when this tire is mounted and inflated, but not under load, the neutral or mean meridian fiber of its radial carcass re-inforcement follows, between the points of tangency of the radial carcass reinforcement with the bead ring and with the tread reinforcement, the natural equilibrium profile such that cos ? = , the quantity (Rs12 - Re12) being equal to about k (RSo2 - Reo2), Po being the rated inflation pressure and P1 the inflation pressure such that the tire retains its rated deflection under the effect of an overload, k being a positive coefficient between 1 and the value of the ratio , and sin .beta.1=
Description
~s~
The present invention relates to a tire Eor medium and heavy load-bearing vehicles (delivery vans and trucks) provided with a radial carcass reinEorcement anchored to at least one bead ring in each bead and with a tread reinforcement comprising at least two oblique plies of wires or cables parallel in each ply and crossed from one ply to tnenext.
The inventionrelates more particularly to such tires which do not have an independent inner tube, i.e~, tubeless tires, and are mounted on air-tight wheel rims having frusto-conical seats for the beads of the tires. Such wheel rimscorrespond to the standards in use and have bead seats with a an angle of inclination of about 15 with respect to the axis of rotation of the wheels. Finally, the invention concerns tires of the type defined above whose ratio H/B of the radial height H of the tire on the rim to the maximum axial width B
of the tire is between 0.6 and 1.
In order to make the loading of medium and heavy load-bearing vehicles easier and more proEitable, there is a tendency to reduce the height of the loading plat~orm of these vehicles.
This results in themaintaining or decreasing of the outside diameter and a considerable overload of between 30% and 100%
as compared with the rated load of such tires contemplated by the manufacturer or the standards in use, in the event that it is desired to avoid multiplying the number of axles. To this load there corresponds a rated inflation pressure.
One solution consists in increasing the inflation pressure of such tires. However, this solution, on the one hand, has an unfavorable effect on the wear of the tread while, on the other hand, it increases~he meridian tension on the radial carcass reinforcement at the height of the beads and therefore the tension on the bead ring to which the radial carcass reinforcement is anchored, generally by being turned ~65~J~, around it. In order to overcome this increase in tension, it is necessary to simultaneously reinforce the radial carcass reinforcement and the bead rings in order to maintain a satisfactory life of such tires. This results in a substantial increase in the cost of the tires.
The object of the present invention is to increase the rated load of tires of the same size and of the type in question by 30% to 100%, and preferably by at least 50%, and to do so without modifying, on the one hand, the tension on the bead rings, that is to say without reinforcing the bead rings, and, on the other hand, the ~eflection of the tire which corresponds to the rated load and pressure, the increase in the meridian tension on the radial carcass reinforcement being furthermore equal to the increase of the inflation pressure necessary to maintain the deflection of the tire at about its rated value.
The solution in accordance with the invention consists in selecting a natural equilibrium ~roEile of the neutral or mean meridian fiber of the radial carcass reinforcement such that the tension on the bead rings remains practically equal to the tenslon under the effect of the rated pressure and such that the in¢rease in the meridian tension on the radial carcass reinforcement at the level of the bead rings remains less than the increase in the inflation pressure.
Accordingly, the tubeless tire oE the invention has a radial carcass reinforcement whose neutral or mean meridian fiber follows, with respect to the tire of the same size referred to as the reference tire, between the bead rings and the tread reinforcement,thenatural equilibrium profile in accordance with the law cos ~ =R2 _ Rel2 in which the quantity RS12 - Rel2
The present invention relates to a tire Eor medium and heavy load-bearing vehicles (delivery vans and trucks) provided with a radial carcass reinEorcement anchored to at least one bead ring in each bead and with a tread reinforcement comprising at least two oblique plies of wires or cables parallel in each ply and crossed from one ply to tnenext.
The inventionrelates more particularly to such tires which do not have an independent inner tube, i.e~, tubeless tires, and are mounted on air-tight wheel rims having frusto-conical seats for the beads of the tires. Such wheel rimscorrespond to the standards in use and have bead seats with a an angle of inclination of about 15 with respect to the axis of rotation of the wheels. Finally, the invention concerns tires of the type defined above whose ratio H/B of the radial height H of the tire on the rim to the maximum axial width B
of the tire is between 0.6 and 1.
In order to make the loading of medium and heavy load-bearing vehicles easier and more proEitable, there is a tendency to reduce the height of the loading plat~orm of these vehicles.
This results in themaintaining or decreasing of the outside diameter and a considerable overload of between 30% and 100%
as compared with the rated load of such tires contemplated by the manufacturer or the standards in use, in the event that it is desired to avoid multiplying the number of axles. To this load there corresponds a rated inflation pressure.
One solution consists in increasing the inflation pressure of such tires. However, this solution, on the one hand, has an unfavorable effect on the wear of the tread while, on the other hand, it increases~he meridian tension on the radial carcass reinforcement at the height of the beads and therefore the tension on the bead ring to which the radial carcass reinforcement is anchored, generally by being turned ~65~J~, around it. In order to overcome this increase in tension, it is necessary to simultaneously reinforce the radial carcass reinforcement and the bead rings in order to maintain a satisfactory life of such tires. This results in a substantial increase in the cost of the tires.
The object of the present invention is to increase the rated load of tires of the same size and of the type in question by 30% to 100%, and preferably by at least 50%, and to do so without modifying, on the one hand, the tension on the bead rings, that is to say without reinforcing the bead rings, and, on the other hand, the ~eflection of the tire which corresponds to the rated load and pressure, the increase in the meridian tension on the radial carcass reinforcement being furthermore equal to the increase of the inflation pressure necessary to maintain the deflection of the tire at about its rated value.
The solution in accordance with the invention consists in selecting a natural equilibrium ~roEile of the neutral or mean meridian fiber of the radial carcass reinforcement such that the tension on the bead rings remains practically equal to the tenslon under the effect of the rated pressure and such that the in¢rease in the meridian tension on the radial carcass reinforcement at the level of the bead rings remains less than the increase in the inflation pressure.
Accordingly, the tubeless tire oE the invention has a radial carcass reinforcement whose neutral or mean meridian fiber follows, with respect to the tire of the same size referred to as the reference tire, between the bead rings and the tread reinforcement,thenatural equilibrium profile in accordance with the law cos ~ =R2 _ Rel2 in which the quantity RS12 - Rel2
2 P
(RSl2 - Rel ) = K (Rso~ - Reo2j, and sin ~1 = sin ~OI k being a positive coeffic:ient between _ .
1 and pl but at all times diEferent from these limits ~ c 2 (1~ k ~ pl), and the quantity Rel is equal to Rt2 - cos ~1 (RS12- Rel2) .
On the one hand, the natural equilibrium profile of the neutral or mean meridian fiber of a radial carcass r-einforce-ment follows the law (1) cos ~ = R2 _ Re2 . In this law:
Re2 - Re2 - ~ is the angle of the tangent to the natural equilibrium profile with the axis oE rotation of- the tire at a point located at the radial distance R from said axis, with cos ~ < 0 for R < Re and cos ~ ~0 for R ~ Rè;
Rs is the radial distance from the axis of rotation of the tire to the point where the natural equilibrium profile has a tangent parallel to the axis of rotation of thè tire;
- Re is the radial distance from the axis of rotation of the tire to the point where the natural equilibrium profile reaches its maximum axial width or else where the natural equilibrium profile has a tangent pe~pendicular to the axis of rotation of the tire.
- On the other hand, the tension T on the bead ring is expressed by the relationship (2) T = p sin ~ ~ in which expression p is the inflation pressure and ~ the angle formed by the tangent to the radial carcass reinforcement at the point of contact of the radial carcass reinforcement with the bead ring and by the axis o~ rotation of the tire.
F~rthermore, themeridian tension t ~per unit of circumferential length~ on the radial carcass reinforcement at the level of the bead ring is expressed by the relation-ship (3) t = p Rs2 _ Re2in which express:ion Rtis the radial~is~t tance from the axis of rotation of the ti~e to thepointofcontact of the radial carcass reinforcement with tne bead ring.
At the rated inflation pressure p contemplated for the rate load of the reference tire, relationships (1), (2) and (3) above become:
cos ~ = R _ Reo2 (rated natural equilibrium profile) to = p sin 6 RSO Reo (rated tension on the bead ring) to _ Po Rso2 - Reo2 (rated meridian tension on the radiaI
2~t carcass rèinforcement at the level of the bead ring) In accordance with the invention, at the pressure Pl which is sufficient for the deflectlon of the tire under over-load to be approximately equal to the rated deflection of the reference tire, on the one hand, the tension Tl on the bead ring is approximately equal to the rated tension To while the meridian tension tl on the radial carcass reinforcement reaches the value k tol k being between 1 and the value of the ratio pl . It follows that tl = k = Pl . (Rs12 - Rel2) , hence Po t~ PO (RSO2 Reo ) the value of the quantity (RS12 - Rel2) to be introduced into the law giving thenatural equilibrium profile of the neutral or mean meridian fiber of the radial carcass reinforcement in accordance with the invention.
From the e~uivalence of the tenSinSTl and T on the bead ring one derives the value of the angle ~1 at the level 6s~æ
of the bead riny from the value of the angle ~ by taking in-to account the above value of the quantity (R51 - Rel ) in accordance with the invention, namely sin ~1 = sln ~O This k makes it possible to calculate the quantity Rel2 on basis oE the expression cos ~ = Rt2 _ Rel2 by noting that RS12 - Rel2 cos ~1 < -In practice, the invention makes it possible to select a meridian tension (and therefore the reinforcement) on theradial carcass reinforcement which is less than the increase in the inflation pressure which is suitable for maintaining the constancy of the deflection~ Preferably k will be be~ween 1.15 and 1.30.
Preferably also there is used a radial carcass reinforcement formed essentially of a single ply of cables, preferably steel wires.
In this case, the neutral or mean meridian fiber follows, by convention, the axis o~ the cables. In the case of a multi-ply radial carcass reinforcement, the neutral or mean meridian fiber is, by convention~ located midway between the outer and inner plies~
The embodiment of the invention which is shown in the drawing relates to a tire 1 of dimensions 9 5-17.5 (in inches). The sole figure of this drawing is a view in meridian or transverse semi-section (not to scale) of this tire.
The radius Rj of the bead seat 3 of the rim 2 ¢orresponding to this tire 1 is equal to 222 mm, the bead seats 3 having a conicity of 15.
Under the rated conditions stipulated by the standar~s in use, such a (rated) tire supports a load of 1700 kg under a rated inflation pressure PO of 6~75 bars and a static deflection of about 33 mm.
The point of tangency 8 of the radial carcass re-inforcement 6 with the bead ring 7 is located at the distance Rt ~ 238 mm from the axis of rotation YY' of the tire. Further-more, this tire has an ~/B ratio of 0.9.
For an overload equal to 2655 kg it is necessary to inflate the tire to a pressure Pl of 8.5 bars in order to obtain a deflection of 36 mm which is close to therated deflec-tion of the reference tire (overload 8 57~).
The tire l is shown mounted on a rim 2 with a frusto, conical bead seat 3 inclined 15 with respect to the axis of rotation of the wheel, which axis is indicated by the straight line YY'. The trace XX' of the equatorial plane on the plane of the drawing is the axis of symmetry of the meridian half-section of the tire l. Themaximum axial half-width of the tire is equal to B/2 and the height H on the rim is measured from the end of the radius Rj of the bead seat 3, as defined by the standards in use.
The tire l comprises below the tread 4 a tread re-inEorcement 5 formed of two plies of cables 51 and 52, The radial carcass reinforcement 6 is tangent to the tread reinforcement 5 at the point 8' and tangent to the bead ring 7 of the bead lO at the point 8. The neutral or mean merldian fiber follows the trace 6. Rt corresponds to the point 8.
The single-ply radial carcass reinforcement 6 is anchored to the bead ring 7 by means of a turned-up end strand 6'.
Contrary to the customary arrangement with a radical carcass reinforcement 6 formed of a single ply of steel cables, as shown in the drawing the end 6" of the turned-up portion 6' is located radially outward of the corresponding end 9' of the stiffening ply 9. The stiffening ply 9 is composed of oblique ~65~2 cables and is arranged axially outward of the turr~ed-up portion 6' of the radial carcass reinforcement 6. The invention thus makes it possible to decrease the width of the stiffenillg ply 9.
The other, radially inner, end 9" of the stiffening ply 9 is located at an axial distance A Erom the equatorial plane of trace XX', which is greater than the minimum axial distance a of the radial carcass reinforcement 6 in the bead lO o Despite the increase in the inflation pres~ure this results in an increase in the flexibility of the bead.
Preferably, the radial distance d of the end 6" of the turned-up portion 6' from the top 11 of the flange 2' of the rim 2 is between 5% and 20% of the height ~ of the tire 1.
In the case of the 9.5-17.5 tire selected as the example, the coefficient k having to be between 1 and 8-75 = 1.26, k is equal to 1.20.
6.75 F'or a tire suitable to bear the rated load Rso = 393 mm ....
Reo = 320 mm and ~O = 43.
One obtains therefrom the value of the ~uantity (R512 - Rel2) = 49 600 mm2 corresponding to the tire in accordance with the invention. Likewise ~1 = 34 By noting that for two points of the natural equilibrium profile corresponding to the radii Rl and R2 one has cos ~ = R12 _ Rel2 and (RS12 - Rel2~
cos ~2 = R2_ - Rel , one easily traces step by (RS12 - Rel2) step the natural equilibrium profile of the neutral or mean meridian fiber of the radial carcass reinforcement in accordance with ~he invention by means of a computer using the relationship s~z cos ~1 ~ cos ~2 =RI _ R2 _ (RS12 - Rel2) starting from the value ~1 = 34 for Rt = 238 mm.
On this trace one notes the calculated values RS1 = 384 mm R 1 = 313 mm e In accordance with the invention r the tension on the bead ring has practically not changed:
~ O = 1198 kg and Tl = 1179 kg.
In accordance with the inventionl the meridian tension on the radial carcass reinforcement has increased by about 20~.
To = 7.38 kg/mm Tl = 8.86 kg/mm while the inflation pressure has increased 26%.
On the other hand, despite an increase in the load of 57% referred to the rated load, it should be noted `t'nat the resistanee to rolling of the tire in aceordanee with the invention per 1000 kilograms of load and at a speed of 70 km/hour is 8% less than that of the known (rated) tire.
(RSl2 - Rel ) = K (Rso~ - Reo2j, and sin ~1 = sin ~OI k being a positive coeffic:ient between _ .
1 and pl but at all times diEferent from these limits ~ c 2 (1~ k ~ pl), and the quantity Rel is equal to Rt2 - cos ~1 (RS12- Rel2) .
On the one hand, the natural equilibrium profile of the neutral or mean meridian fiber of a radial carcass r-einforce-ment follows the law (1) cos ~ = R2 _ Re2 . In this law:
Re2 - Re2 - ~ is the angle of the tangent to the natural equilibrium profile with the axis oE rotation of- the tire at a point located at the radial distance R from said axis, with cos ~ < 0 for R < Re and cos ~ ~0 for R ~ Rè;
Rs is the radial distance from the axis of rotation of the tire to the point where the natural equilibrium profile has a tangent parallel to the axis of rotation of thè tire;
- Re is the radial distance from the axis of rotation of the tire to the point where the natural equilibrium profile reaches its maximum axial width or else where the natural equilibrium profile has a tangent pe~pendicular to the axis of rotation of the tire.
- On the other hand, the tension T on the bead ring is expressed by the relationship (2) T = p sin ~ ~ in which expression p is the inflation pressure and ~ the angle formed by the tangent to the radial carcass reinforcement at the point of contact of the radial carcass reinforcement with the bead ring and by the axis o~ rotation of the tire.
F~rthermore, themeridian tension t ~per unit of circumferential length~ on the radial carcass reinforcement at the level of the bead ring is expressed by the relation-ship (3) t = p Rs2 _ Re2in which express:ion Rtis the radial~is~t tance from the axis of rotation of the ti~e to thepointofcontact of the radial carcass reinforcement with tne bead ring.
At the rated inflation pressure p contemplated for the rate load of the reference tire, relationships (1), (2) and (3) above become:
cos ~ = R _ Reo2 (rated natural equilibrium profile) to = p sin 6 RSO Reo (rated tension on the bead ring) to _ Po Rso2 - Reo2 (rated meridian tension on the radiaI
2~t carcass rèinforcement at the level of the bead ring) In accordance with the invention, at the pressure Pl which is sufficient for the deflectlon of the tire under over-load to be approximately equal to the rated deflection of the reference tire, on the one hand, the tension Tl on the bead ring is approximately equal to the rated tension To while the meridian tension tl on the radial carcass reinforcement reaches the value k tol k being between 1 and the value of the ratio pl . It follows that tl = k = Pl . (Rs12 - Rel2) , hence Po t~ PO (RSO2 Reo ) the value of the quantity (RS12 - Rel2) to be introduced into the law giving thenatural equilibrium profile of the neutral or mean meridian fiber of the radial carcass reinforcement in accordance with the invention.
From the e~uivalence of the tenSinSTl and T on the bead ring one derives the value of the angle ~1 at the level 6s~æ
of the bead riny from the value of the angle ~ by taking in-to account the above value of the quantity (R51 - Rel ) in accordance with the invention, namely sin ~1 = sln ~O This k makes it possible to calculate the quantity Rel2 on basis oE the expression cos ~ = Rt2 _ Rel2 by noting that RS12 - Rel2 cos ~1 < -In practice, the invention makes it possible to select a meridian tension (and therefore the reinforcement) on theradial carcass reinforcement which is less than the increase in the inflation pressure which is suitable for maintaining the constancy of the deflection~ Preferably k will be be~ween 1.15 and 1.30.
Preferably also there is used a radial carcass reinforcement formed essentially of a single ply of cables, preferably steel wires.
In this case, the neutral or mean meridian fiber follows, by convention, the axis o~ the cables. In the case of a multi-ply radial carcass reinforcement, the neutral or mean meridian fiber is, by convention~ located midway between the outer and inner plies~
The embodiment of the invention which is shown in the drawing relates to a tire 1 of dimensions 9 5-17.5 (in inches). The sole figure of this drawing is a view in meridian or transverse semi-section (not to scale) of this tire.
The radius Rj of the bead seat 3 of the rim 2 ¢orresponding to this tire 1 is equal to 222 mm, the bead seats 3 having a conicity of 15.
Under the rated conditions stipulated by the standar~s in use, such a (rated) tire supports a load of 1700 kg under a rated inflation pressure PO of 6~75 bars and a static deflection of about 33 mm.
The point of tangency 8 of the radial carcass re-inforcement 6 with the bead ring 7 is located at the distance Rt ~ 238 mm from the axis of rotation YY' of the tire. Further-more, this tire has an ~/B ratio of 0.9.
For an overload equal to 2655 kg it is necessary to inflate the tire to a pressure Pl of 8.5 bars in order to obtain a deflection of 36 mm which is close to therated deflec-tion of the reference tire (overload 8 57~).
The tire l is shown mounted on a rim 2 with a frusto, conical bead seat 3 inclined 15 with respect to the axis of rotation of the wheel, which axis is indicated by the straight line YY'. The trace XX' of the equatorial plane on the plane of the drawing is the axis of symmetry of the meridian half-section of the tire l. Themaximum axial half-width of the tire is equal to B/2 and the height H on the rim is measured from the end of the radius Rj of the bead seat 3, as defined by the standards in use.
The tire l comprises below the tread 4 a tread re-inEorcement 5 formed of two plies of cables 51 and 52, The radial carcass reinforcement 6 is tangent to the tread reinforcement 5 at the point 8' and tangent to the bead ring 7 of the bead lO at the point 8. The neutral or mean merldian fiber follows the trace 6. Rt corresponds to the point 8.
The single-ply radial carcass reinforcement 6 is anchored to the bead ring 7 by means of a turned-up end strand 6'.
Contrary to the customary arrangement with a radical carcass reinforcement 6 formed of a single ply of steel cables, as shown in the drawing the end 6" of the turned-up portion 6' is located radially outward of the corresponding end 9' of the stiffening ply 9. The stiffening ply 9 is composed of oblique ~65~2 cables and is arranged axially outward of the turr~ed-up portion 6' of the radial carcass reinforcement 6. The invention thus makes it possible to decrease the width of the stiffenillg ply 9.
The other, radially inner, end 9" of the stiffening ply 9 is located at an axial distance A Erom the equatorial plane of trace XX', which is greater than the minimum axial distance a of the radial carcass reinforcement 6 in the bead lO o Despite the increase in the inflation pres~ure this results in an increase in the flexibility of the bead.
Preferably, the radial distance d of the end 6" of the turned-up portion 6' from the top 11 of the flange 2' of the rim 2 is between 5% and 20% of the height ~ of the tire 1.
In the case of the 9.5-17.5 tire selected as the example, the coefficient k having to be between 1 and 8-75 = 1.26, k is equal to 1.20.
6.75 F'or a tire suitable to bear the rated load Rso = 393 mm ....
Reo = 320 mm and ~O = 43.
One obtains therefrom the value of the ~uantity (R512 - Rel2) = 49 600 mm2 corresponding to the tire in accordance with the invention. Likewise ~1 = 34 By noting that for two points of the natural equilibrium profile corresponding to the radii Rl and R2 one has cos ~ = R12 _ Rel2 and (RS12 - Rel2~
cos ~2 = R2_ - Rel , one easily traces step by (RS12 - Rel2) step the natural equilibrium profile of the neutral or mean meridian fiber of the radial carcass reinforcement in accordance with ~he invention by means of a computer using the relationship s~z cos ~1 ~ cos ~2 =RI _ R2 _ (RS12 - Rel2) starting from the value ~1 = 34 for Rt = 238 mm.
On this trace one notes the calculated values RS1 = 384 mm R 1 = 313 mm e In accordance with the invention r the tension on the bead ring has practically not changed:
~ O = 1198 kg and Tl = 1179 kg.
In accordance with the inventionl the meridian tension on the radial carcass reinforcement has increased by about 20~.
To = 7.38 kg/mm Tl = 8.86 kg/mm while the inflation pressure has increased 26%.
On the other hand, despite an increase in the load of 57% referred to the rated load, it should be noted `t'nat the resistanee to rolling of the tire in aceordanee with the invention per 1000 kilograms of load and at a speed of 70 km/hour is 8% less than that of the known (rated) tire.
Claims (3)
1. A tubeless tire for medium and heavy load-bearing vehicles (delivery vans and trucks) provided with a radial carcass reinforcement anchored to at least one bead ring in each bead and with a tread reinforcement comprising at least two oblique plies of wires or cables parallel in each ply and crossed from one ply to the next, the tire being intended to be mounted on a wheel rim having frustoconical bead seats, and having an H/R ratio of between 0.6 and 1, H being the radial height of the tire on the rim and B being the maximum axial width of the tire, characterized by the fact that when it is mounted and inflated, but not under load, the neutral or mean meridian fiber of its radial carcass reinforcement follows, between the points of tangency of the radial carcass reinforce-ment with the bead ring and with the tread reinforcement, the natural equilibrium profile such that cos ? = , the quantity (Rs12 - Rel2) being equal to about k (Rso2 - Reo2), with Po being rated inflation pressure and P1 the inflation pressure such that the tire retains its rated deflection under the effect of an over-load, k being a positive coefficient between 1 and the value of the ratio , and sin .beta.1 = and the quantity Re12 being equal to Rt2 - cos .beta.1 (Rs12 - Re12), the terms ?, .beta., R, Re, Rs and Rt being defined as follows:
- .beta. is the angle of the tangent to the natural equilibrium profile with the axis of rotation of the tire at a point located at a radial distance R from said axis with cos .PHI. <0 for R <Re and cos .PHI. > 0 for R>Re;
- .beta. is the angle formed by the tangent to the radial carcass reinforcement at the point of contact of the radial carcass reinforcement with the bead ring and by the axis of rotation of the tire;
- Re is the radial distance from the axis of rotation of the tire to the point where the natural equilibrium profile reaches its maximum axial width or else where the natural equilibrium profile has a tangent perpendicular to the axis of rotation of the tire;
- Rs is the radial distance from the axis of rotation of the tire to the point where the natural equilibrium profile has a tangent parallel to the axis of rotation of the tire, and - Rt is the radial distance from the axis of rotation of the tire to the point of contact of the radial carcass reinforcement with the bead ring, with .beta.o, Reo and Rso being the values thereof at Po and .beta.1, Re1 and Rs1 being the values thereof at P1.
- .beta. is the angle of the tangent to the natural equilibrium profile with the axis of rotation of the tire at a point located at a radial distance R from said axis with cos .PHI. <0 for R <Re and cos .PHI. > 0 for R>Re;
- .beta. is the angle formed by the tangent to the radial carcass reinforcement at the point of contact of the radial carcass reinforcement with the bead ring and by the axis of rotation of the tire;
- Re is the radial distance from the axis of rotation of the tire to the point where the natural equilibrium profile reaches its maximum axial width or else where the natural equilibrium profile has a tangent perpendicular to the axis of rotation of the tire;
- Rs is the radial distance from the axis of rotation of the tire to the point where the natural equilibrium profile has a tangent parallel to the axis of rotation of the tire, and - Rt is the radial distance from the axis of rotation of the tire to the point of contact of the radial carcass reinforcement with the bead ring, with .beta.o, Reo and Rso being the values thereof at Po and .beta.1, Re1 and Rs1 being the values thereof at P1.
2. The tubeless tire according to claim 1, characterized by the fact that the coefficient k is between 1.15 and 1.30.
3. The tubeless tire according to claim 1 or claim 2, characterized, on the one hand, by the fact that the end of the portion of the radial carcass reinforcement which is turned up around the bead ring is located radially outward of the cor-responding end of a stiffening ply of the bead, said stif-fening ply being arranged axially outward of said turned-up portion, and, on the other hand, by the fact that the end of the turned-up portion of the radial carcass reinforcement is located preferably at a distance of between 5% and 20% of the height of the tire, referred to the top of the flange of the rim.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR7833652A FR2442149A1 (en) | 1978-11-27 | 1978-11-27 | RADIAL CARCASS TIRE |
| FR78-33652 | 1978-11-27 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1116502A true CA1116502A (en) | 1982-01-19 |
Family
ID=9215480
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000340574A Expired CA1116502A (en) | 1978-11-27 | 1979-11-26 | Radial carcass tire |
Country Status (16)
| Country | Link |
|---|---|
| EP (1) | EP0013194A1 (en) |
| JP (1) | JPS5572406A (en) |
| AR (1) | AR221514A1 (en) |
| AT (1) | AT377231B (en) |
| AU (1) | AU526325B2 (en) |
| BE (1) | BE879989A (en) |
| BR (1) | BR7907692A (en) |
| CA (1) | CA1116502A (en) |
| DE (1) | DE2947149A1 (en) |
| EG (1) | EG14591A (en) |
| ES (1) | ES486229A1 (en) |
| FR (1) | FR2442149A1 (en) |
| GB (1) | GB2035925B (en) |
| IT (1) | IT1119548B (en) |
| LU (1) | LU81924A1 (en) |
| NL (1) | NL7908561A (en) |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2506683A1 (en) * | 1980-06-04 | 1982-12-03 | Michelin Rech Tech | Geometric limits for radial tyre carcass ply section profiles - to minimise risk of tyre rim disengagement if under-pressurised |
| JPS609922B2 (en) * | 1980-07-02 | 1985-03-14 | 株式会社ブリヂストン | Pneumatic radial tire for heavy loads |
| JPS5747203A (en) * | 1980-09-05 | 1982-03-18 | Bridgestone Corp | Pneumatic flat radial tire for heavy load |
| IT1144202B (en) * | 1981-04-29 | 1986-10-29 | Firestone Int Dev Spa | ROAD VEHICLE TIRE |
| JPS6060005A (en) * | 1983-09-14 | 1985-04-06 | Bridgestone Corp | Pneumatic radial tire passenger vehicle |
| DE3562586D1 (en) * | 1985-02-26 | 1988-06-16 | Goodyear Tire & Rubber | A pneumatic tire |
| JPH0775922B2 (en) * | 1985-03-01 | 1995-08-16 | 住友ゴム工業株式会社 | Radial tire |
| US5253689A (en) * | 1986-12-25 | 1993-10-19 | Bridgestone Corporation | Heavy duty radial tire carcass profile |
| CA1313115C (en) * | 1986-12-25 | 1993-01-26 | Kiyoshi Sato | Heavy duty radial tire |
| US4840213A (en) * | 1987-04-03 | 1989-06-20 | Bridgestone Corporation | Heavy duty low profile pneumatic radial tires |
| JPH0342307A (en) * | 1989-07-06 | 1991-02-22 | Ohtsu Tire & Rubber Co Ltd :The | Radial tire |
| JP2695716B2 (en) * | 1991-09-17 | 1998-01-14 | 住友ゴム工業株式会社 | Radial tires for heavy loads |
| EP1028859B1 (en) * | 1997-04-03 | 2002-06-26 | The Goodyear Tire & Rubber Company | Ply path controlled by precured apex |
| US6298893B1 (en) | 1997-04-03 | 2001-10-09 | The Goodyear Tire & Rubber Company | Ply path controlled by precured apex |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2120421A5 (en) * | 1970-12-30 | 1972-08-18 | Michelin & Cie | |
| BE792557A (en) * | 1971-12-31 | 1973-06-12 | Michelin & Cie | IMPROVEMENTS TO TIRE PACKAGES |
| FR2281239A1 (en) * | 1974-08-05 | 1976-03-05 | Michelin & Cie | IMPROVEMENTS TO TIRE PACKAGES |
| US4077455A (en) * | 1976-01-05 | 1978-03-07 | The Goodyear Tire & Rubber Company | Radial ply pneumatic tire and rim assembly |
| US4096900A (en) * | 1976-01-05 | 1978-06-27 | The Goodyear Tire & Rubber Company | Earthmover tire and rim assembly |
| US4029139A (en) * | 1976-01-05 | 1977-06-14 | The Goodyear Tire & Rubber Company | Tire and rim assembly |
-
1978
- 1978-11-27 FR FR7833652A patent/FR2442149A1/en active Granted
-
1979
- 1979-11-13 BE BE0/198082A patent/BE879989A/en not_active IP Right Cessation
- 1979-11-14 EP EP79400863A patent/EP0013194A1/en not_active Ceased
- 1979-11-15 JP JP14877579A patent/JPS5572406A/en active Pending
- 1979-11-21 GB GB7940289A patent/GB2035925B/en not_active Expired
- 1979-11-22 DE DE19792947149 patent/DE2947149A1/en not_active Withdrawn
- 1979-11-22 ES ES486229A patent/ES486229A1/en not_active Expired
- 1979-11-26 LU LU81924A patent/LU81924A1/en unknown
- 1979-11-26 NL NL7908561A patent/NL7908561A/en not_active Application Discontinuation
- 1979-11-26 AU AU53186/79A patent/AU526325B2/en not_active Ceased
- 1979-11-26 IT IT7969278A patent/IT1119548B/en active
- 1979-11-26 EG EG704/79A patent/EG14591A/en active
- 1979-11-26 CA CA000340574A patent/CA1116502A/en not_active Expired
- 1979-11-26 AR AR279022A patent/AR221514A1/en active
- 1979-11-26 AT AT0747879A patent/AT377231B/en not_active IP Right Cessation
- 1979-11-27 BR BR7907692A patent/BR7907692A/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| ATA747879A (en) | 1984-07-15 |
| DE2947149A1 (en) | 1980-06-04 |
| ES486229A1 (en) | 1980-06-16 |
| BR7907692A (en) | 1980-06-24 |
| BE879989A (en) | 1980-03-03 |
| AT377231B (en) | 1985-02-25 |
| FR2442149B1 (en) | 1981-05-29 |
| IT1119548B (en) | 1986-03-10 |
| IT7969278A0 (en) | 1979-11-26 |
| FR2442149A1 (en) | 1980-06-20 |
| GB2035925B (en) | 1983-06-15 |
| EG14591A (en) | 1984-09-30 |
| LU81924A1 (en) | 1980-04-22 |
| JPS5572406A (en) | 1980-05-31 |
| AU526325B2 (en) | 1983-01-06 |
| EP0013194A1 (en) | 1980-07-09 |
| GB2035925A (en) | 1980-06-25 |
| AR221514A1 (en) | 1981-02-13 |
| AU5318679A (en) | 1980-05-29 |
| NL7908561A (en) | 1980-05-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |