CA1105817A - Pneumatic tire of elastic material without reinforcement - Google Patents
Pneumatic tire of elastic material without reinforcementInfo
- Publication number
- CA1105817A CA1105817A CA322,051A CA322051A CA1105817A CA 1105817 A CA1105817 A CA 1105817A CA 322051 A CA322051 A CA 322051A CA 1105817 A CA1105817 A CA 1105817A
- Authority
- CA
- Canada
- Prior art keywords
- pneumatic tire
- radius
- meridian profile
- point
- crown
- 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
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
- B60C5/00—Inflatable pneumatic tyres or inner tubes
- B60C5/01—Inflatable pneumatic tyres or inner tubes without substantial cord reinforcement, e.g. cordless tyres, cast tyres
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Tires In General (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE:
A pneumatic tire comprising a tread at a crown and a body which comprises, on both sides of the crown, a shoulder extended by a sidewall terminated by a bead, and formed of elastic material without reinforcement is characterized by the fact that the radius of curvature pm of the meridian profile of the inner wall follows the law
A pneumatic tire comprising a tread at a crown and a body which comprises, on both sides of the crown, a shoulder extended by a sidewall terminated by a bead, and formed of elastic material without reinforcement is characterized by the fact that the radius of curvature pm of the meridian profile of the inner wall follows the law
Description
~1~5~7 The present invention relates to improvements in pneumatic tires of elastic material without reinforcement. The absence of reinforcement, however, does not exclude the use, in the beads of these tires, of bead rings whose function is to assure the seating and possibly the tightness of the beads on the rim.
The crown of such tires may be formed of a single elastic material, for instance, the material forming the side-walls. However, it may also be formed of several superimposed elastic materials adhering to each other, for instance, at least two materials one of which, arranged radially outward, is suitable to form the tread, while the other, arranged radially on the inside of the tread, is suitable to form the ; mechanically resistant body of the tire in the region of the crown.
Tires of the type under consideration may assume as a result of the inflation pressure, shapes which are very different from the shapes of the uninflated tires.
It particular, the region of the crown may thus show a considerable increase in curvature. An exaggeration of the curvature may cause-an unfavorable distribution of the wear of the tread. This drawback may, under the effect of the fatigue and/or thermal stresses to which the region of the crown is subjected during the travel of the tire, be amplified by the increase, creepage or failure of the rigidity of the material forming the mechanically resistant part of the crown region.
In order to overcome these drawbacks, it has been proposed to provide said region with a reinforcement or reinforcing elements or to increase its thickness. These ~-~ solutions result, in particular, in an increase in the cost of the tires o~ the type in question and/or a decrease in the comfort upon travel, due to the increase in the stiffness ., . ~
1'58~ 7 of the crown.
It is furthermore important to note the shape, and more particularly the meridian profile, assumed by the body of such tires under the influence of a given inflation pressure. This, for instance, in order to determine their outside diameter in use or the meridian contour to be imparted to the tread. This determination requires the use and employ-ment of expensive means of computation.
The object of the present invention is to avoid these deformations upon inflation and therefore the drawbacks which they entail.
The fundamental ide~ of the invention consists therefore in providing the meridian profile of the inner wall of the tire with a radius of curvature Pm such that the circumferential deformation ~c is zero. The determination of such a profile requires the use of costly computation means.
This is why a preferred variant of the present invention consists in using, in first approximation, the relationships serving for the calculation of membranes in order to evaluate the meridian radius of curvature of such a profile. This radius then follows the law Y_ ~
(a) Pm = 2 cos ~ ~ 2 3 + ~
In the accompanying drawing, which is intended, together with the corresponding portion of the present specification, to facilitate an understanding of the invention, - Fig. 1 shows schematically half of a meridian profile of the inner wall of a tire in accordance with the invention with dimensions utilizing the parameters which appear in the above-indicated law of variation, and -58~7 - Fig. 2 illustrates a radial half section through a tire in accordance with the invention.
Fig. 1 shows, in part, half of a meridian profile 1 of the inner wall ~11 of Fig. 2) of a pneumatic tire in a~cordance with the invention. The running point A of this profile is located at a distance y from the axis of rotation X-X' of the tire. The distance y is measured parallel to the trace Y-Y' of the equatorial plane of the tire. ~e is the radius of the point E of the inner wall which is located at the greatest axial distance from the equatorial line Y-Y'.
Rs is the radius of the point S of the crown which is furthest from the axis of rotation X-X'. ~ is the angle formed by the tangent AT to the inner profile 1 at the point A with the straight line AD passing through the point A and parallel to the axis of rotation X-X'. Pm is the meridian radius of ~ curvature at the point A of the inner profile 1.
; The calculation of the coordinates of the different points constituting the profile 1 is advantageously effected by means of a computer.
The tire 2 in accordance with the invention shown in radial half section in Fig. 2 is a pneumatic tire of millimeter size 135-330. It comprises a tread 3 at a crown 5 and a body 4 which compris0s, on both sides of the crown 5, a shoulder 6 extended by a sidewall 7 terminated by a bead 8.
~ The bead 8 is reinforced by at least one bead ring 9 and rests ; on a rim 10 (shown in part). The inner wall 11 has a trace inaccordance with the invention. The value Rs of the radius at the crown is equal to 273 mm and the ratio Re/RS is equal to 0.79. The rim 10 is a standard 4-inch rim.
0 The object of the invention being essentially to avoid the creation of a state of circumferential deformations in the region of the crown and of the shoulders as a result of _ 3 -'' .
'S8~7 the placing under pressure of the tire, it may be sufficient to impart to the inner wall 11 a profile in accordance with the invention in the crown, the shoulders and the portions of the sidewalls radially outward of the points E where the inner - wall 11 reaches its greatest distance from the equatorial line Y-Y`. ~lowever, it is preferable that the inner wall 11 follow the said meridian profile from one bead 8 to the other.
The inner wall of the tire can be given a meridian curvature in accordance with the invention at the time of the manufacture of the tire. The tire can also be manufactured in such a manner that the meridian curvature in accordance with the invention is reached only when the tire is in position on its rim, but not inflated.
The tread may be of a suitable material different from the material or materials of the body of the tire, all of these materials adhering to each other.
In practice, the advantages of the invention are obtained when the meridian radius of curvature Pm defined above by law (a) is located between the two limits defined by the following relationships:
' (b) Plm 3 cos ~ Re2 and 5 + 2 ::: 1 _ e2 (c) ~2m = 11 cos ~ R 2 15 + 7 2
The crown of such tires may be formed of a single elastic material, for instance, the material forming the side-walls. However, it may also be formed of several superimposed elastic materials adhering to each other, for instance, at least two materials one of which, arranged radially outward, is suitable to form the tread, while the other, arranged radially on the inside of the tread, is suitable to form the ; mechanically resistant body of the tire in the region of the crown.
Tires of the type under consideration may assume as a result of the inflation pressure, shapes which are very different from the shapes of the uninflated tires.
It particular, the region of the crown may thus show a considerable increase in curvature. An exaggeration of the curvature may cause-an unfavorable distribution of the wear of the tread. This drawback may, under the effect of the fatigue and/or thermal stresses to which the region of the crown is subjected during the travel of the tire, be amplified by the increase, creepage or failure of the rigidity of the material forming the mechanically resistant part of the crown region.
In order to overcome these drawbacks, it has been proposed to provide said region with a reinforcement or reinforcing elements or to increase its thickness. These ~-~ solutions result, in particular, in an increase in the cost of the tires o~ the type in question and/or a decrease in the comfort upon travel, due to the increase in the stiffness ., . ~
1'58~ 7 of the crown.
It is furthermore important to note the shape, and more particularly the meridian profile, assumed by the body of such tires under the influence of a given inflation pressure. This, for instance, in order to determine their outside diameter in use or the meridian contour to be imparted to the tread. This determination requires the use and employ-ment of expensive means of computation.
The object of the present invention is to avoid these deformations upon inflation and therefore the drawbacks which they entail.
The fundamental ide~ of the invention consists therefore in providing the meridian profile of the inner wall of the tire with a radius of curvature Pm such that the circumferential deformation ~c is zero. The determination of such a profile requires the use of costly computation means.
This is why a preferred variant of the present invention consists in using, in first approximation, the relationships serving for the calculation of membranes in order to evaluate the meridian radius of curvature of such a profile. This radius then follows the law Y_ ~
(a) Pm = 2 cos ~ ~ 2 3 + ~
In the accompanying drawing, which is intended, together with the corresponding portion of the present specification, to facilitate an understanding of the invention, - Fig. 1 shows schematically half of a meridian profile of the inner wall of a tire in accordance with the invention with dimensions utilizing the parameters which appear in the above-indicated law of variation, and -58~7 - Fig. 2 illustrates a radial half section through a tire in accordance with the invention.
Fig. 1 shows, in part, half of a meridian profile 1 of the inner wall ~11 of Fig. 2) of a pneumatic tire in a~cordance with the invention. The running point A of this profile is located at a distance y from the axis of rotation X-X' of the tire. The distance y is measured parallel to the trace Y-Y' of the equatorial plane of the tire. ~e is the radius of the point E of the inner wall which is located at the greatest axial distance from the equatorial line Y-Y'.
Rs is the radius of the point S of the crown which is furthest from the axis of rotation X-X'. ~ is the angle formed by the tangent AT to the inner profile 1 at the point A with the straight line AD passing through the point A and parallel to the axis of rotation X-X'. Pm is the meridian radius of ~ curvature at the point A of the inner profile 1.
; The calculation of the coordinates of the different points constituting the profile 1 is advantageously effected by means of a computer.
The tire 2 in accordance with the invention shown in radial half section in Fig. 2 is a pneumatic tire of millimeter size 135-330. It comprises a tread 3 at a crown 5 and a body 4 which compris0s, on both sides of the crown 5, a shoulder 6 extended by a sidewall 7 terminated by a bead 8.
~ The bead 8 is reinforced by at least one bead ring 9 and rests ; on a rim 10 (shown in part). The inner wall 11 has a trace inaccordance with the invention. The value Rs of the radius at the crown is equal to 273 mm and the ratio Re/RS is equal to 0.79. The rim 10 is a standard 4-inch rim.
0 The object of the invention being essentially to avoid the creation of a state of circumferential deformations in the region of the crown and of the shoulders as a result of _ 3 -'' .
'S8~7 the placing under pressure of the tire, it may be sufficient to impart to the inner wall 11 a profile in accordance with the invention in the crown, the shoulders and the portions of the sidewalls radially outward of the points E where the inner - wall 11 reaches its greatest distance from the equatorial line Y-Y`. ~lowever, it is preferable that the inner wall 11 follow the said meridian profile from one bead 8 to the other.
The inner wall of the tire can be given a meridian curvature in accordance with the invention at the time of the manufacture of the tire. The tire can also be manufactured in such a manner that the meridian curvature in accordance with the invention is reached only when the tire is in position on its rim, but not inflated.
The tread may be of a suitable material different from the material or materials of the body of the tire, all of these materials adhering to each other.
In practice, the advantages of the invention are obtained when the meridian radius of curvature Pm defined above by law (a) is located between the two limits defined by the following relationships:
' (b) Plm 3 cos ~ Re2 and 5 + 2 ::: 1 _ e2 (c) ~2m = 11 cos ~ R 2 15 + 7 2
Claims (4)
1. A pneumatic tire having an equatorial line, an axis of rotation and comprising a tread at a crown and a body which comprises, on both sides of the crown, a shoulder extended by a sidewall terminated by a bead, and formed of elastic material without reinforcement, characterized by the fact that the radius of curvature ?m at a point A of the meridian profile of the inner wall of said tire follows the law (a) at least in the portion of the pneumatic tire located radially outward of the points where the meridian profile reaches its greatest axial distance from the equatorial line; wherein ? is the angle formed by a tangent to said meridian profile at said point A with a straight line passing through said point A
and being parallel to said axis of rotation;
y is the distance of said point A from said axis of rotation, measured parallel to said equatorial line, and Re is the radius of the point of said meridian profile located at the greatest axial distance from said equatorial line.
and being parallel to said axis of rotation;
y is the distance of said point A from said axis of rotation, measured parallel to said equatorial line, and Re is the radius of the point of said meridian profile located at the greatest axial distance from said equatorial line.
2. A pneumatic tire according to claim 1, characterized by the fact that the radius of curvature ?m of the meridian profile of the inner wall is located between the two limits defined by the following relationships:
(b) and (c)
(b) and (c)
3. A pneumatic tire according to claim 1 or claim 2, characterized by the fact that the radius of curvature pm of the meridian profile of the inner wall follows the said law from one bead to the other.
4. A pneumatic tire according to claim 1 or claim 2, characterized by the fact that its tread consists of a suitable tread material which is different from the material or materials of the body of the pneumatic tire.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR7805155 | 1978-02-21 | ||
| FR7805155A FR2417405A1 (en) | 1978-02-21 | 1978-02-21 | IMPROVEMENT IN TIRES IN NON-ARMORED ELASTIC MATERIAL |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1105817A true CA1105817A (en) | 1981-07-28 |
Family
ID=9204935
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA322,051A Expired CA1105817A (en) | 1978-02-21 | 1979-02-21 | Pneumatic tire of elastic material without reinforcement |
Country Status (13)
| Country | Link |
|---|---|
| JP (1) | JPS54122505A (en) |
| AU (1) | AU525625B2 (en) |
| BE (1) | BE874131A (en) |
| BR (1) | BR7901136A (en) |
| CA (1) | CA1105817A (en) |
| DE (1) | DE2906764A1 (en) |
| ES (1) | ES477867A1 (en) |
| FR (1) | FR2417405A1 (en) |
| GB (1) | GB2014916B (en) |
| IT (1) | IT1118392B (en) |
| LU (1) | LU80947A1 (en) |
| NL (1) | NL7901356A (en) |
| SE (1) | SE7901497L (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3358900B2 (en) * | 1993-12-16 | 2002-12-24 | 住友ゴム工業株式会社 | Pneumatic tire |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ZA7259B (en) * | 1971-01-16 | 1972-09-27 | Dunlop Ltd | Tyres |
| FR2314059A1 (en) * | 1975-06-12 | 1977-01-07 | Michelin & Cie | UNREINFORCED TIRE ENCLOSURES |
| FR2314061A1 (en) * | 1975-06-12 | 1977-01-07 | Michelin & Cie | NON-REINFORCED TIRE COVERS, WITH REINFORCED SHOULDERS |
| US4006767A (en) * | 1975-10-08 | 1977-02-08 | The Firestone Tire & Rubber Company | Pneumatic tires |
-
1978
- 1978-02-21 FR FR7805155A patent/FR2417405A1/en active Granted
-
1979
- 1979-02-13 BE BE193430A patent/BE874131A/en not_active IP Right Cessation
- 1979-02-19 JP JP1828479A patent/JPS54122505A/en active Pending
- 1979-02-20 IT IT67375/79A patent/IT1118392B/en active
- 1979-02-20 LU LU80947A patent/LU80947A1/en unknown
- 1979-02-20 AU AU44391/79A patent/AU525625B2/en not_active Expired
- 1979-02-20 SE SE7901497A patent/SE7901497L/en not_active Application Discontinuation
- 1979-02-20 ES ES477867A patent/ES477867A1/en not_active Expired
- 1979-02-21 GB GB7906102A patent/GB2014916B/en not_active Expired
- 1979-02-21 DE DE19792906764 patent/DE2906764A1/en not_active Ceased
- 1979-02-21 NL NL7901356A patent/NL7901356A/en not_active Application Discontinuation
- 1979-02-21 CA CA322,051A patent/CA1105817A/en not_active Expired
- 1979-02-21 BR BR7901136A patent/BR7901136A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| AU525625B2 (en) | 1982-11-18 |
| LU80947A1 (en) | 1979-06-18 |
| BE874131A (en) | 1979-05-29 |
| FR2417405A1 (en) | 1979-09-14 |
| ES477867A1 (en) | 1979-08-01 |
| IT7967375A0 (en) | 1979-02-20 |
| AU4439179A (en) | 1979-08-30 |
| GB2014916A (en) | 1979-09-05 |
| BR7901136A (en) | 1979-10-02 |
| JPS54122505A (en) | 1979-09-22 |
| NL7901356A (en) | 1979-08-23 |
| SE7901497L (en) | 1979-08-22 |
| FR2417405B1 (en) | 1981-09-18 |
| IT1118392B (en) | 1986-02-24 |
| DE2906764A1 (en) | 1979-08-23 |
| GB2014916B (en) | 1982-07-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |