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CN-122029059-A - Studded tyre with improved grip on wet and/or snowy ground

CN122029059ACN 122029059 ACN122029059 ACN 122029059ACN-122029059-A

Abstract

The invention relates to a studded tyre comprising a tread comprising a studded shoe (36 c), said studded shoe (36 c) comprising a housing (42) housing a stud (44), the maximum overall diameter of the upper portion (51) of the stud extending over two thirds of the overall height (H) of the stud being Dc. Each receptacle (42) is surrounded by a solid anchoring region (54) of the nail (44), said solid anchoring region (54) having a maximum overall diameter Dmax. For each receptacle (42), each insert pad (36 c) has a dimension Lmin separating two opposing edges of the insert pad (36 c) and passing a minimum distance through the center of the pin (48). The average value M of Dmax/Lmin ratios of all the accommodating parts (42) and the nail insert cushion blocks (36 c) satisfies M less than or equal to 73 percent. The average value M 'of the Dc/Dmax ratios of all the nails (44) and the receiving portion (42) satisfies M'. Gtoreq.37%.

Inventors

  • JANIN NICOLAS
  • F. Sarasin

Assignees

  • 米其林集团总公司

Dates

Publication Date
20260512
Application Date
20241001
Priority Date
20231009

Claims (10)

  1. 1. Studded tyre (10) comprising a tread (14), said tread (14) comprising pads (36 u, 38u, 36c, 38 c), said pads (36 u, 38u, 36c, 38 c) comprising studded pads (36 c, 38 c), each studded pad (36 c, 38 c) comprising at least one receptacle (42) accommodating a stud (44), the maximum overall diameter Dc of the upper portion (51) of the stud (44) extending over two thirds of the overall height (H) of said stud (44), Each receptacle (42) being surrounded by a solid anchoring zone (54) for anchoring the nail (44), each solid anchoring zone (54) having a maximum overall diameter Dmax, For each receiving portion (42), each insert pad (36 c, 38 c) has a dimension Lmin, which is the minimum distance separating two opposite edges (37, 39) of the insert pad (36 c, 38 c) and passing through the center of the receiving portion (42), The method is characterized in that the average value M of Dmax/Lmin ratios of all the accommodating parts (42) and the spike pad blocks (36 c, 38 c) of the spike tire (10) meets M≤73%, and the average value M 'of Dc/Dmax ratios of all the spikes (44) and the accommodating parts (42) of the spike tire (10) meets M'. Gtoreq.37%.
  2. 2. Studded tyre (10) according to the preceding claim, wherein M is equal to or less than 70%, preferably M is equal to or less than 67%.
  3. 3. Studded tyre (10) according to any one of the preceding claims, wherein M '. Gtoreq.40%, preferably M'. Gtoreq.43%.
  4. 4. Studded tyre (10) according to any one of the preceding claims, wherein the average value of Dmax values is strictly less than 14 mm, preferably less than or equal to 12mm, more preferably less than or equal to 11 mm.
  5. 5. Studded tyre (10) according to any one of the preceding claims, wherein the average value of Lmin values is strictly less than 19 mm, preferably less than or equal to 17 mm.
  6. 6. Studded tyre (10) according to any one of the preceding claims, wherein the average value of Dc values is strictly less than 10 mm, preferably less than or equal to 6 mm.
  7. 7. The studded tyre (10) of any one of the preceding claims, wherein the spacer blocks (36 u, 38u, 36C, 38C) are delimited at least by main cuts (22, 24, 26, 28, 30) comprising N transverse main cuts (22, 24), N satisfying N/C ≡36 transverse main cuts (22, 24)/meter, C being the circumference of the studded tyre (10) expressed in meters.
  8. 8. Studded tyre (10) according to any one of the preceding claims, wherein the spacer blocks (36 u, 38u, 36c, 38 c) are delimited at least by main cuts (22, 24, 26, 28, 30), the studded tyre (10) having a volumetric void fraction relative to the main cuts greater than or equal to 25.0%, preferably strictly greater than 28.5%.
  9. 9. Studded tyre (10) according to any one of the preceding claims, wherein the surface density of the studs (44) per square decimeter of the tread (14) is greater than or equal to 8.0, preferably greater than or equal to 8.7, more preferably greater than or equal to 9.3, even more preferably greater than or equal to 9.5.
  10. 10. The studded tyre (10) of any one of the preceding claims, wherein each of the studded blocks (36 c, 38 c) includes one or more secondary cuts (40) formed in the studded block (36 c, 38 c), the secondary cuts (40) having a width of less than or equal to 2.0 mm, preferably less than or equal to 1.2 mm.

Description

Studded tyre with improved grip on wet and/or snowy ground Technical Field The present invention relates to a tire. A tire is understood to mean a tire casing intended to form, by interaction with a support element (such as a rim), a cavity that can or cannot be pressurized to a pressure greater than atmospheric pressure. The tire according to the invention has a generally toroidal shape structure that exhibits rotational symmetry about the principal axis of the tire. Background Studded tires sold under the X-ICE NORTH 4 series under the MICHELIN trademark are known in the prior art. Although such tires are excellent in performance, in particular grip on ice and low road wear, they are not perfect in grip on wet and snowy ground. Disclosure of Invention The present invention aims to improve the grip of prior art tires on wet and/or snowy ground without compromising their grip on ice. To this end, the invention relates to a studded tyre comprising a tread comprising a spacer comprising a studded spacer, each of the studded spacer comprising at least one housing portion accommodating the studs, the maximum overall diameter Dc of the upper portion of the stud extending over two thirds of the total height of the stud, each housing portion being surrounded by a solid anchoring area for anchoring the stud, each solid stud having a maximum overall diameter Dmax, for each housing portion, each of the studded spacer having a dimension Lmin which is the minimum distance separating two opposite edges of the studded spacer and passing through the centre of the housing portion, the average M of the Dmax/Lmin ratios of all housing portions of the studded tyre and the studded spacer satisfying m≤73%, and the average M 'of the Dc/Dmax ratios of all studs and housing portions of the studded tyre satisfying M'. Gtoreq.37%. The tire according to the invention has an improved grip on wet ground compared to the tires of the prior art, without reducing its grip on ice. In particular, by reducing the value of Dmax for a given value of Dc, the present invention makes it possible to reduce the value of Lmin, in other words, the present invention makes it possible to reduce the size of the pad. This reduction in the size of the pods may allow for an increase in the size of the cutouts defining the pods to enhance grip on wet ground and/or an increase in the number of pods to enhance grip on snowy ground. This is because increasing the size of the cut defining the pad makes it possible to increase the void fraction, so that the tread can be drained more effectively. Increasing the number of pads makes it possible to increase the number of edges in contact with the snow layer covering the ground, thereby breaking the snow layer more effectively. Conversely, when the value of Dmax is reduced for a given Dc value, there is a risk that the nail may be less firmly secured in the solid anchoring area due to the reduced material surrounding the nail in the solid anchoring area, such less firmly secured resulting in reduced grip performance on ice. The invention makes it possible to avoid this trade-off by making the value of the Dmax/Lmin ratio relatively low (in other words by increasing the amount of material surrounding the solid anchoring region in the pad). Thus, the decrease in the amount of material surrounding the staples in the solid anchor areas is compensated for by the increase in the amount of material surrounding the solid anchor areas in the spacer. According to the invention, the maximum overall diameter Dc is the maximum overall diameter of the upper part of the nail extending over two thirds of the overall height of the nail. In particular, the upper portion of the spike is relevant to characterize the degree of firmness with which the spike is fixed in the solid anchoring zone, in particular because it is close to the tread surface, as opposed to being more firmly fixed in the innermost portion of the tread by anchoring at a greater depth of the tread. The maximum overall diameter Dc is determined by seeking the diameter of a circle which is inscribed by the portion having the largest diameter in the upper part extending over two thirds of the overall height of the nail, the circle being contained in a plane substantially perpendicular to the general direction in which the nail extends. According to the present invention, the solid anchoring region has a function of anchoring the nail and thus preventing it from coming out of the receiving part. By "solid" is meant that the area does not include any cavities or holes that would prevent the staples from being securely fastened in the receptacles. The maximum overall diameter Dmax is determined by seeking the diameter of a circle that is contained in a plane that is substantially perpendicular to the general direction in which the staples extend, and that is inscribed by the portion of the solid anchoring region that has the greatest diameter. In the case where the accommod