Search

CN-115835968-B - Tire comprising at least one sidewall with protective protuberance

CN115835968BCN 115835968 BCN115835968 BCN 115835968BCN-115835968-B

Abstract

The present invention relates to a tyre (1), more particularly a tyre (1) intended for private passenger vehicles and comprising at least one sidewall (3) with a sidewall (3) protuberance, said sidewall (3) protuberance being close to the junction of the tyre with the tyre mounting rim (2), to reduce aerodynamic resistance and thus resistance to forward movement of the wheel, thus contributing to lower fuel consumption and thus to reduce CO 2 emissions. According to the invention, when the tyre (1) is mounted on the rim (2) and inflated to a pressure defined by the "ETRTO" standard, the radially inner end I of the protuberance (6) is arranged radially inside the radially outermost point J of the rim flange (21) with a radial distance H1 at most equal to 10mm, or radially outside the radially outermost point J of the rim flange (21) with a radial distance H1 at most equal to 4 mm.

Inventors

  • B. Gimar
  • O. Milhov
  • V-J. Chapter

Assignees

  • 米其林集团总公司

Dates

Publication Date
20260505
Application Date
20210607
Priority Date
20200610

Claims (14)

  1. 1. Tyre (1) for private passenger vehicles intended to be mounted on a rim (2) defined by the standards of the "european tyre and rim technical organization" or "ETRTO", comprising: -two sidewalls (3) connecting the crown (4) to two respective beads (5), each bead (5) being intended to be in contact with a rim flange (21) having a radially outermost point J, At least one sidewall (3) comprising a protuberance (6), said protuberance (6) being intended to protect the rim flange (21) and extending radially inwards and axially inwards from the axially external surface (31) of the sidewall and circumferentially along the circumferential direction (XX') of the tire, Said protuberance (6) having a meridian section (61) delimited by a contour (62) comprising a radially innermost point, called radially inner end I of the protuberance (6), in any meridian plane (YZ) comprising the rotation axis (YY') of the tyre, Characterized in that, when the tyre (1) is mounted on the rim (2) and inflated to a pressure defined by the ETRTO standard, the radially inner end I of the protuberance (6) is arranged radially inside the radially outermost point J of the rim flange (21) with a radial distance H1 at most equal to 10mm, or radially outside the radially outermost point J of the rim flange (21) with a radial distance H1 at most equal to 4mm, the axially inner connection K of said protuberance (6) with the axially outer surface (31) of the sidewall being arranged axially outside the radially outermost point J of the rim flange (21) such that the intermediate direction D1 of the meridian section (61) of said protuberance (6) forms an angle a with the radial direction (ZZ') at least equal to 5 °.
  2. 2. Tyre (1) according to claim 1, the rim flange (21) comprising, in any meridian plane (YZ), a radially outer circumferential portion (211), the radially outer circumferential portion (211) being connected to a substantially axial radially inner portion (213) by means of an intermediate radial portion (212), wherein the radially inner end I of the protuberance (6) is axially arranged outside the radial portion (212) of the rim flange (21) with an axial distance B1 at least equal to 5mm.
  3. 3. Tyre (1) according to any one of claims 1 or 2, the rim flange (21) comprising, in any meridian plane (YZ), a radially outer circumferential portion (211), the radially outer circumferential portion (211) being connected to a substantially axial radially inner portion (213) by means of an intermediate radial portion (212), wherein the radially inner end I of the protuberance (6) is axially arranged outside the radial portion (212) of the rim flange (21) with an axial distance B1 at most equal to 21 mm.
  4. 4. Tyre (1) according to claim 1, the meridian section (61) of the protuberance (6) having a greater dimension in the median direction D1, wherein the median direction D1 of the meridian section (61) of the protuberance (6) forms an angle a with the radial direction (ZZ') at least equal to 10 °.
  5. 5. Tyre (1) according to claim 1, the meridian section (61) of the protuberance (6) having a greater dimension in the median direction D1, wherein the median direction D1 of the meridian section (61) of the protuberance (6) forms an angle a with the radial direction (ZZ') at most equal to 30 °.
  6. 6. Tyre (1) according to claim 1, wherein the profile (62) of the protuberance (6) comprises an axially internal connection K of the protuberance (6) to the axially external surface (31) of the sidewall, wherein a line tangent to the profile (62) has an axial direction (YY') radially arranged outside the radially outermost point J of the rim flange (21) with a radial distance H2 at least equal to 3 mm.
  7. 7. Tyre (1) according to claim 6, wherein the axially internal connection K of said protuberance (6) to the axially external surface (31) of the sidewall is radially arranged outside the radially outermost point J of the rim flange (21) with a radial distance H2 at most equal to 10 mm.
  8. 8. Tyre (1) according to any one of claims 6 to 7, wherein the radius of curvature at the axially internal connection K of the protuberance (6) with the axially external surface (31) of the sidewall is defined as a connection radius R, said connection radius R being at least equal to 2mm.
  9. 9. Tyre (1) according to any one of claims 6 to 7, wherein the thickness E of the meridian section (61) of the protuberance (6) is at least equal to 1.5mm, said thickness E being measured along an axial straight line D2, said axial straight line D2 being radially positioned inside the axially internal connection K of the protuberance (6) to the axially external surface (31) of the sidewall and being arranged at a radial distance H3 equal to 3mm from the axially internal connection K.
  10. 10. Tyre (1) according to any one of claims 6 to 7, wherein the thickness E of the meridian section (61) of the protuberance (6) is at most equal to 8mm, said thickness E being measured along an axial straight line D2, said axial straight line D2 being radially positioned inside the axially internal connection K of the protuberance (6) to the axially external surface (31) of the sidewall and being arranged at a radial distance H3 equal to 3mm from the axially internal connection K.
  11. 11. Tyre (1) according to claim 1, wherein said protuberance (6) is in contact with the rim flange (21) via at least one contact means (63) distributed in the circumferential direction.
  12. 12. Tyre (1) according to claim 1, wherein each sidewall (3) comprises a protuberance (6).
  13. 13. Tyre (1) according to claim 1, the tyre (1) having a radially outermost point M in the median plane (XZ) and a theoretical height H in the sense of "ETRTO" standard measured between the radially outermost point M of the tyre (1) and the radially innermost point of the rim flange (21), wherein the tyre (1) has an axially outermost point N on the axially outer surface (31) of each sidewall, said axially outermost point N being arranged with a radial distance H4 at least equal to H/2+5mm with respect to the radially outermost point M in the radial direction.
  14. 14. A mounting assembly comprising a tyre (1) according to any one of claims 1 to 13, said tyre (1) being mounted on a rim (2) thereof.

Description

Tire comprising at least one sidewall with protective protuberance Technical Field The object of the present invention is a tire, more specifically a tire intended to be mounted to a private passenger vehicle and comprising at least one sidewall with a protection protrusion intended to protect the connection between the tire and the tire mounting rim. Background In view of the current concern for environmental protection, a long-felt goal of vehicle manufacturers is to reduce their CO 2 emissions by significantly reducing the fuel consumption of private passenger vehicles. It is well known that fuel consumption increases with the resistance to forward movement of the vehicle. The main component of the resistance to forward movement is caused by aerodynamic resistance applied to the moving vehicle. It has been shown that a wheel mounted to a vehicle (i.e. a tyre mounted on a rim) has a significant impact on the generation of aerodynamic drag. In general, it is known that objects moving in a fluid (e.g., wheels rotating in air) are subjected to pressure and friction due to the viscosity of air. The combination of these two types of forces constitutes aerodynamic drag. This aerodynamic resistance corresponds to an aerodynamic resistance that impedes the forward movement of an object in a fluid (e.g., the forward movement of a wheel in air). This aerodynamic resistance is proportional to the square of the forward speed of the vehicle. Above a certain speed (typically above 30 km/h) and on level ground aerodynamic drag is the main source of drag applied to the forward movement of the wheels. It is well known that aerodynamic drag applied to a wheel is created by turbulence in the air flow in the vicinity of the wheel. In order to reduce such aerodynamic drag, it is correspondingly effective to retard the separation of the air flow from the tire sidewall as much as possible. The faster the air flow separates from the tire sidewall, such as the greater the roughness of the tire's logo or the connection between the tire and the tire mounting rim. Thus, the external profile of the tire, including a perfectly smooth sidewall (which is continuous with the flange of the mounting rim), is theoretically optimal for aerodynamic drag. Disclosure of Invention Tires are generally composed of a tread intended to be in contact with the ground via a tread surface and connected at its two axial ends to two sidewalls extending through two beads intended to be in contact with the flange of the rim. Since the tire has a geometry that revolves around its axis of rotation, the tire can be described in a reference cylinder comprising a circumferential direction, an axial direction and a radial direction, respectively. Hereinafter, the circumferential direction (or longitudinal direction), the axial direction (or transverse direction) and the radial direction respectively denote a direction tangential to the tread surface and oriented in the direction of rotation of the tire, a direction parallel to the axis of rotation of the tire and a direction perpendicular to the axis of rotation of the tire. The radial plane (or meridian plane) is defined by the radial direction and the axial direction and includes the axis of rotation of the tire. The circumferential plane is defined by a radial direction and a circumferential direction, so that the circumferential plane is perpendicular to the axis of rotation of the tyre. The circumferential plane passing through the middle of the tread is called the equatorial plane (or median plane). Thus, in the present document, the terms "radially", "axially" and "circumferentially" denote "in the radial direction", "in the axial direction" and "in the circumferential direction", respectively. The expression "radially internal" or "radially external" means "closer" or "further" respectively in the radial direction to the rotation axis of the tyre. The expressions "axially internal" and "axially external" mean "closer" to the median plane of the tyre and "further" from the median plane of the tyre, respectively, in the axial direction. The connection between the tire and its mounting rim is an area that is particularly susceptible to damage (e.g., a crash of a sidewalk), especially for tires having lower sidewalls. Such damage may result in localized deformation of the rim flange, which may result in loss of sealing and thus in loss of inflation pressure of the tire. This may also cause damage to the tire bead in contact with the rim flange, which may significantly shorten the service life of the tire. To protect this junction, it is known to provide protective cords in the radially inner portion of the tire sidewall close to the bead. The presence of such protective cords, which constitute the sidewall projections, however, causes geometrical discontinuities between the radially inner portion of the tire sidewall and the rim flange, creating turbulence in the air flow and thus increasing aerodynamic drag.