CA3088282C

CA3088282C - Stud and pneumatic vehicle tyre with studs

Info

Publication number: CA3088282C
Application number: CA3088282A
Authority: CA
Inventors: Jan Schlittenhard; Maik Kotter; Torben SPECHTMEYER
Original assignee: Continental Reifen Deutschland GmbH
Current assignee: Continental Reifen Deutschland GmbH
Priority date: 2018-02-02
Filing date: 2019-01-03
Publication date: 2023-03-14
Anticipated expiration: 2039-01-03
Also published as: RU2742060C1; CA3088282A1; CN111683824B; EP3746314A1; EP3746314B1; WO2019149461A1; CN111683824A; DE102018201611A1

Abstract

A stud (1, 1') having a stud body (2, 2') which has a base flange (6, 6') and which is composed of a non-metallic, elastic material, in particular a rubber material, and having a stud pin (3, 3') which is composed of hard metal and which is anchored in an insert (4, 4') and which projects with an end portion beyond the stud body, said insert being situated within the stud body and having a base part (4a, 4'a), wherein the base part (4a, 4'a) together with an encasing layer (5, 5') composed of the material of the stud body forms the base flange (6, 6') of the stud body, and wherein the base flange has an outer contour which is of symmetrical design with respect to at least one plane of symmetry (Si, S2) and which has two long sides and two narrow sides. The outer contour of the base part differs geometrically from that of the base flange, such that, on one side of the base part, which is assigned to a long side and/or to a narrow side, the encasing layer (5, 5') has at least one portion in which said encasing layer is thicker than at the opposite side of the base part.

Description

Description Stud and pneumatic vehicle tyre with studs The invention relates to a stud for anchoring in a stud hole of a tread of a pneumatic vehicle tire, having a stud body which is composed of a nonmetallic, elastic material, in particular a rubber material, and which comprises a base flange, and having a stud pin, which stud pin is composed of hard metal and is anchored in an insert which is situated within the stud body and which comprises a base part, and which stud pin projects with an end portion beyond the stud body, wherein the base part together with a enveloping layer composed of the material of the stud body forms the base flange of the stud body, and wherein the base flange has an outer contour which is designed symmetrically with respect to at least one plane of symmetry and which has two longitudinal sides and two narrow sides.
Studs are normally held in the stud holes of the tread of pneumatic vehicle tires by a combination of positive locking and clamping. Conventional studs are composed of a stud body which is composed of aluminum or steel and in which the stud pin, which projects beyond the tread surface and which is composed of hard metal, is held.
It has already been proposed to use studs with stud bodies composed of rubber or of plastic.
For example, WO 2017/088995 Al has disclosed a stud of the type mentioned in the introduction, in the case of which the stud pin and the insert composed of plastic or aluminum are embedded into a rubber casing or into rubber material. The particular advantages of this embodiment lie in the fundamental material properties of the rubber body. Its low density of approximately 1 g/cm3 makes rubber particularly light in comparison with aluminum or steel. Replacing aluminum or steel with rubber as body material therefore leads to a reduction in the stud weight, which has a positive effect inter alia on road wear and the formation of fine dust. The elastic material properties of the Date Recue/Date Received 2022-02-23

2 rubber however have yet further advantages. Firstly, the elastic body material dampens impacts, with the result that smaller forces act on stones in the road surface or on particles of gritting material. This effect also reduces the road wear and the formation of fine dust.
Moreover, stud bodies composed of rubber are superior to those composed of aluminum or steel in terms of abrasion behavior, because they have completely different wear behavior.
Since stones in the road surface and grit normally have a greater hardness than aluminum or even steel, a stud body composed of aluminum or steel is heavily abraded, as a result of which the stud body height and the diameter of the stud body decrease. This has the effect that the edge regions of the stud body at the stud holes are subjected to cutting abrasion which erodes the edge regions, whereby the gap between the stud and the surrounding rubber matrix increases in size. This promotes the ingress of sand and small stones, which further accelerate the abrasion of the stud body. Stud bodies composed of rubber can have similar abrasion behavior to the rubber material of the tread, as a result of which gaps between the stud body and the tread material at least substantially no longer arise. The .. elastic characteristics of rubber furthermore give rise to embedding of the stud in the rubber material of the tread, which has a favorable effect on the durability of the stud.
The invention is based on the object of utilizing, more effectively than before and in particular optimally, the elastic properties, mentioned in the introduction, of the material of the stud body in order to optimize the embedding stiffness of the stud in the rubber material of the tread.
The stated object is achieved according to the invention in that the outer contour of the base part differs geometrically from that of the base flange, such that the enveloping layer has, at that side of the base part which is assigned to a longitudinal side and/or to a narrow side, at least one portion in which said enveloping layer is thicker than at the opposite side of the base part.
The invention permits an optimization of the ice performance of the stud through targeted influencing of the embedding stiffness by means of corresponding design and configuration of the base part and of the base flange in order to form regions with different layer thicknesses of the enveloping layer at mutually opposite sides of the base flange. The forces Date Recue/Date Received 2020-07-13

3 exerted on the stud pin under braking, under traction and during cornering on icy underlying surfaces are transmitted into the base flange with particular intensity owing to the lever action. A thicker enveloping layer with greater elasticity and better damping behavior is therefore provided at that region of the base flange side where softer embedding is advantageous. A thinner and therefore less elastic enveloping layer gives rise to stiffer embedding of the studs under particular loads.
In a preferred embodiment, the at least one portion in which the enveloping layer has a relatively great thickness forms an enveloping layer cushion. The embodiment as a cushion is associated with the advantage of a substantially continuous transition into the adjacent enveloping layer portions via layer thicknesses which become thinner.
Also particularly advantageous is an embodiment of the stud in which the base flange has outer surfaces which, in plan view, run in a straight manner along the longitudinal sides of said base flange and run in an outwardly curved manner along the narrow sides of said base flange. Here, the longitudinal sides may, in plan view, run in a straight manner and in particular parallel to one another, and the two narrow sides are in particular of arcuately outwardly rounded design, and may also be of corresponding design. The longitudinal sides may furthermore run such that the base flange has a greater width at one narrow side than at the other narrow side. The base flange therefore has, in particular, one of the common and uniform, in plan view substantially oval, shapes which permit good anchoring of the stud in conventional stud holes of treads in pneumatic vehicle tires.
Also particularly advantageous is an embodiment of the base part of the insert with longitudinal and narrow sides which are assigned to the longitudinal and narrow sides of the base flange and which have outwardly rounded delimiting surfaces at the narrow sides and with, along one longitudinal side, two delimiting surfaces which run at an obtuse internal angle with respect to one another, such that the enveloping layer forms, to the outer surface of the base flange, two enveloping layer cushions which are preferably triangular in plan view. The obtuse internal angle between the delimiting surfaces amounts in particular to 150 to 170 , and the greatest thickness of the enveloping layer cushions amounts, in the preferred embodiment, to 0.35 mm to 1.0 mm, in particular 0.7 mm to 1.0 mm.
Particularly Date Recue/Date Received 2020-07-13

4 advantageous embedding stiffness of a stud designed in this way is obtained if the stud is positioned in the tread and in the tread halves thereof such that the longitudinal sides of the base flange extend in a circumferential direction and the enveloping layer cushions in the base flange are situated in each case closer to the adjacent tread edge. In the event of the stud pin being loaded in an axial or predominantly axial direction with respect to the non-cushioned base flange edge, the stud can be well supported in said region, and forces for good lateral guidance can be optimally transmitted. In the event of loading in the opposite axial direction, for example owing to slipping movements during the flattening-out of the tire, then the relatively soft embedding of the stud in the region of the enveloping layer cushions takes effect, and the stud can deflect in a relatively pliant manner in the desired way.
In the case of an embodiment of the stud with at least one enveloping layer cushion at a longitudinal side of the base part or of the base flange, the enveloping layer has, in those regions where no enveloping layer cushion is formed, a thickness smaller than the greatest thickness of the enveloping layer cushion(s).
In the case of embodiments of the stud with at least one enveloping layer cushion at one longitudinal side of the base part or base flange, a particular design of the stud pin or of its end portion which projects beyond the stud body, and of the grip edges formed there at the top surface, is also particularly advantageous for optimum ice grip. The end portion of the stud pin is elongate transversely with respect to the longitudinal sides of the base flange and of the base part and has two grip edges which extend in the direction of the longitudinal sides and which are of unequal length, wherein the longer grip edge is that which is closer to the longitudinal side at which the enveloping layer cushion(s) is or are formed.
In a further advantageous embodiment of the stud, the base part has longitudinal and narrow sides which are assigned to the longitudinal and narrow sides of the base flange and which have outwardly rounded delimiting surfaces at the narrow sides, wherein at least one of said delimiting surfaces is, in the region of its rounding center, equipped with a flattened portion which runs in particular in a straight manner in plan view, such that the enveloping layer forms an enveloping layer cushion to the outer surface of the base flange.
Date Recue/Date Received 2020-07-13 Here, an embodiment of the stud is particularly preferred in which the narrow sides of the base flange and of the base part are of unequal width, wherein the base part is, at least at its wider narrow side, in the region of the rounding center, equipped with a flattened portion

5 which runs in particular in a straight manner in plan view and which preferably has a length of 2.0 mm to 3.0 mm. The greatest thickness of said enveloping layer cushion amounts in particular to 0.5 mm to 1.0 mm, preferably 0.7 mm to 1.0 mm. It is particularly advantageous here if such studs are positioned in the tread such that the enveloping layer cushion is assigned to, or faces toward, the circumferential direction of the tire. This stud arrangement is particularly favorable for the embedding stiffness in the case of forces which act under traction loading and braking loading on icy underlying surfaces.
In a further preferred and advantageous embodiment of the stud, at each of the outwardly rounded delimiting surfaces, at the narrow sides, in the region of the rounding center, there is provided a flattened portion which runs in a straight manner in plan view, wherein the enveloping layer cushion at the narrow side with the greater width has a greater thickness at its thickest point than the enveloping layer cushion at the narrow side with the smaller width. In this way, the embedding stiffness under braking and traction loading can be influenced in a targeted manner.
In a further advantageous embodiment of said stud, provision is made whereby the base part has, at its longitudinal sides, delimiting surfaces which run in a concavely inwardly curved manner, wherein the enveloping layer is, at these delimiting surfaces, preferably formed so as to have outer surfaces which run in a straight manner in plan view and a correspondingly varying layer thickness of in particular 0.2 mm to 0.4 mm. The layer thickness is therefore smaller along these delimiting surfaces than in the region of enveloping layer cushions at the narrow sides. In the central region of these delimiting surfaces, the layer thickness is at its greatest owing to the concave design of the delimiting surfaces, and can therefore likewise influence the embedding stiffness of the stud.
In the case of this stud embodiment, a particular embodiment of the stud pin or of its grip edges at its outer top surface is of particular advantage for good ice performance. In the Date Recue/Date Received 2020-07-13

6 case of this embodiment, the end portion of the stud pin is, in plan view, elongate transversely with respect to the longitudinal sides of the base flange and of the base part and has grip edges of unequal length in relation to the narrow sides of the base part, wherein the shorter grip edge is that which is situated closer to the enveloping layer cushion at the narrow side or, if enveloping layer cushions are formed at both narrow sides, to the respectively thicker enveloping layer cushion.
The invention furthermore relates to a pneumatic vehicle tire having a tread with studs designed according to the invention, wherein the studs are positioned in the tread such that their relatively long extent is assigned to the circumferential direction, or substantially the circumferential direction. Here, an arrangement is also particularly advantageous in which the studs arc arranged in stud tracks running over the circumference, and, in each stud track, there are situated in each case studs with enveloping layer cushions formed at the narrow sides and studs with enveloping layer cushions formed at the longitudinal sides.
Also particularly favorable is an arrangement of the studs in the tread such that predominantly or exclusively studs with enveloping layer cushions at the narrow sides are formed in the central region of the tread, and primarily or exclusively studs in the case of which the enveloping layer cushions are formed at the longitudinal sides are formed in the lateral regions of the tread.
According to one aspect, there is provided a stud for anchoring in a stud hole of a tread of a pneumatic vehicle tire. The stud having a stud body which is composed of a nonmetallic, elastic material, and which comprises a base flange, and having a stud pin, which stud pin is composed of hard metal and is anchored in an insert which is situated within the stud body and which comprises a base part, and which stud pin projects with an end portion beyond the stud body, wherein the base part together with an enveloping layer composed of the material of the stud body forms the base flange of the stud body, and wherein the base flange has an outer contour which is designed symmetrically with respect to at least one plane of symmetry and which has two longitudinal sides and two narrow sides, characterized in that the outer contour of the base part differs geometrically from that of the base flange, such that the enveloping layer has, at that side of the base part which is Date Recue/Date Received 2022-02-23 6a assigned to a longitudinal side and/or to a narrow side, at least one portion in which said enveloping layer is thicker than at the opposite side of the base part.
According to another aspect, there is provided a pneumatic vehicle tire having a tread with studs as described above, characterized in that the studs are positioned in the tread such that, in each tread half, the enveloping layer cushions in the base flange are situated in each case closer to the adjacent tread edge.
According to another aspect, there is provided a pneumatic vehicle tire having a tread with .. studs as described above, characterized in that the studs are positioned in the tread such that the enveloping layer cushion(s) is or are assigned to, or face(s) toward, the circumferential direction of the tire.
Further features, advantages and details of the invention will now be described in more detail on the basis of the drawing, which illustrates exemplary embodiments.
In the drawing:
figure 1 and figure 2 show side views of a first embodiment of a stud according to the invention, figure 3 shows an oblique view of the stud as per figure 1 and figure 2, figure 4 shows a plan view of the stud according to the first embodiment, Date Recue/Date Received 2022-02-23

7 figure 5 is a sectional illustration along the section plane denoted by the line V-V in figure 4, figure 6 is a sectional illustration along the section plane denoted by the line VI-VI in figure 4, figure 7 is a sectional illustration along the section plane denoted by the line VII-VII in figure 1, figure 8 and figure 9 show side views of a second embodiment of a stud according to the invention, figure 10 shows an oblique view of the stud as per figure 8 and figure 9, figure 11 shows a plan view of the stud according to the second embodiment, figure 12 is a sectional illustration along the section plane denoted by the line XII-XII in figure 11, figure 13 is a sectional illustration along the section plane denoted by the line XIII-XIII in figure 11, figure 14 is a sectional illustration along the section plane denoted by the line XIV-XIV in figure 1, and figure 15 shows a plan view of a circumferential portion of a tread of a pneumatic vehicle tire with a design variant of the arrangement of the studs.
Figures 1 to 14 are simplified illustrations of studs 1, 1' according to the invention.
Expressions such as vertical, above, below and the like used in the following description relate to the illustrations of the studs 1, 1' in the figures.
Date Recue/Date Received 2020-07-13

8 The studs 1 (figure 1 to figure 7) and 1' (figure 8 to figure 14) shown in the figures are composed basically of a stud body 2 (figure 1 to figure 7) and 2' (figure 8 to figure 14) and of a stud pin 3 (figure 1 to figure 7) and 3' (figure 8 to figure 14). In the stud body 2, 2', there is contained an insert 4, 4' which has a base part 4a, 4'a and a pin holder 4b, 4'b, in the center of which in each case the stud pin 3, 3' is anchored, which projects with an end portion 3a, 3'a beyond the stud body 2, 2'. The studs 1, 1' have vertically running central vertical axes a (figures 5 and 6; figures 12 and 13) on which the center of gravity (not designated) of the studs 1, 1' is situated.
The insert 4, 4' is composed of plastic, in particular of a thermosetting plastic or thermoplastic material, or of metal, in particular of aluminum. The pin holder 4, 4', which in the embodiments shown is of block-like form by way of example, extends into the central region of the stud body 2, 2'. The base part 4a, 4'a of the insert 4 is a component which projects beyond the pin holder 4b, 4'b preferably at all sides and whose greatest thickness di (figure 5, figure 12) is of the order of magnitude of 1.0 mm to 1.4 mm.
The stud body 2, 2' has a base flange 6, 6' which is composed of the base part 4a, 4'a of the insert 4, 4' and of an enveloping layer 5, 5' which surrounds the base part 4a, 4'a, such that the base part 4a, 4'a is embedded into the material of the stud body 2, 2'.
Aside from the base flange 6, 6', the stud body 2, 2' is a cylindrical component in the simplified embodiments illustrated. The stud body 2, 2' may however also have some other external form, for example may be of frustoconical or some other conical design.
The stud body 2, 2' is composed of a non metallic, elastic material, preferably a rubber material, in particular a cut-resistant and abrasion-resistant rubber material. Alternatively, the stud body 2, 2' is composed of a thermoplastic vulcanizate with properties similar to rubber materials. Mixture compositions for producing suitable rubber materials, and suitable thermoplastic vulcanizates, are well known to a person skilled in the art in the field of tires. The material of the stud body 2, 2' furthermore encases the end portion 3a, 3'a of the stud pin 3, 3', possibly with or without covering the top surface 7, 7' of the end portion 3a, 3'a.
Date Recue/Date Received 2020-07-13

9 The stud pin 3, 3' is composed in particular of a hard metal and is a component which is of pin-like design and which tapers conically over its length and which is fixedly anchored with its tapered end portion in the pin holder 4b, 4'b. The cross-sectional area of the stud pin 3, 3' becomes continuously smaller along the longitudinal extent of the stud pin 3, 3' owing to the taper of the stud pin 3, 3', but remains geometrically similar in the preferred embodiment of the stud pin 3, 3'.
In the embodiment shown in figure 1 to figure 7, the base part 4a of the insert 4 is an elongate oval component with narrow sides which are of equal width in plan view and with two differently designed longitudinal sides. As shown in particular in figure 7, at the narrow sides, there are situated arcuately outwardly rounded delimiting surfaces 8a, wherein the delimiting surfaces 8a are connected to one another at one longitudinal side by a straight-running delimiting surface 8b and at the other longitudinal side by two delimiting surfaces 8ci and 8c2 which run at an obtuse internal angle a with respect to one another.
The obtuse angle a is of the order of magnitude of 150 to 170 . The two delimiting surfaces 8ci and 8c2 preferably have corresponding lengths, and the transition region thereof into one another is of rounded form in the exemplary embodiment shown.
The enveloping layer 5 surrounds the foot part 4a along the delimiting surfaces 8a and 8b with an in each case constant or virtually constant thickness of the order of magnitude of 0.2 mm to 0.30 mm. Along the delimiting surfaces 8ci and 8c2, the enveloping layer 5 has an outer surface which runs parallel to the outer surface which runs along the delimiting surface 8b at the opposite region of the enveloping layer 5, such that, along the delimiting surfaces 8ci and 8c2, there are enveloping layer cushions 9 which, in plan view (figure 7) or in cross section, are triangular and thickened in relation to the rest of the layer thickness of the enveloping layer 5. The thickness d2 of said enveloping layer cushions 9 is, at its thickest point, of the order of magnitude of 0.35 mm to 1.0 mm, in particular at least 0.7 mm. In the region of the transition rounding between the delimiting surfaces 8ci and 8c2, there is only a very thin rubber layer with a thickness of the order of magnitude of 0.1 mm to 0.15 mm.
Date Recue/Date Received 2020-07-13 In the preferred embodiment, the width bi of the base flange 7 is of the order of magnitude of 6.5 mm to 7.0 mm, in particular 6.7 mm, and its greatest length 11 amounts to 7.7 mm to 8.3 mm, in particular 8.0 mm. Owing to the embodiment of the base part 4a, the stud 1 has a single plane of symmetry which extends through the vertical axis a and which runs at 5 right angles to the longitudinal sides of the base flange 7 and which is represented in figure 4 by the line Si.
In the illustrated and preferred embodiment, the stud pin 3 is likewise of symmetrical design only with respect to the plane of symmetry Si. Of importance for the ice grip is the

10 design of the outer top surface 7 at the end portion 3a of the stud pin 3. The top surface 7 has its greatest extent length along the plane of symmetry Si, such that, in plan view, the stud pin 3 is elongate along the plane of symmetry Si. The length 12 (figure 4) of the top surface 7 amounts to 2.7 mm to 3.2 mm, and the greatest width b2 thereof amounts to 2.0 mm to 2.3 mm. The top surface 7 thus has, at its narrow sides situated in the longitudinal extent, in each case one grip edge 10ai, 10a2 running at right angles to the plane of symmetry Si, wherein the grip edge 10ai is longer than the grip edge 10a2. The length of the grip edge 10ai amounts to 1.6 mm to 2.2 mm, and the length of the grip edge 10a2 is smaller by 0.2 mm to 0.5 mm. The stud pin 3 is anchored in the pin holder 4b such that the longer grip edge 10ai is that which is situated closer to the delimiting surfaces 8ci and 8c2 of the base part 4a of the insert 4.
In the embodiment shown, the two grip edges 10ai, 10a2 are connected to one another in each case by two grip edges 1 lai and 1 1a2 which are of identical design and which run at an obtuse internal angle (3 of the order of magnitude of preferably 160 to 170 with respect to one another. Furthermore, in the embodiment shown, the grip edge llai directly adjoining the grip edge 10ai is shorter than the grip edges 11a2. In alternative embodiments which are not separately illustrated, the grip edges 10ai, 10a2 are connected to one another in each case by a single straight grip edge or by an arcuately outwardly running grip edge.
The grip edges 10ai, 10a2, llai and 11a2 transition, along the stud pin 3, into said correspondingly delimiting side surfaces.
Date Recue/Date Received 2020-07-13

11 The special embodiment of the base part 4a of the insert 4 makes it easier for the insert 4 with the stud pin 3 to be inserted with the correct orientation into the mold in order to be encapsulated with the material of the stud body 2.
.. For the properties of the stud 1, the special embodiment of the base flange 6 with enveloping layer cushions 9 is of importance, which enveloping layer cushions make it possible for the embedding stiffness of the stud 1 inserted in the tread to be influenced and optimized. As indicated for example in figure 4 by the arrow U, the stud 1 is positioned in the tread preferably with its longer extent of the base flange 6 parallel or approximately parallel - with a deviation of up to approximately 15 - to the circumferential direction of the tread, and, in the tread halves, furthermore such that the enveloping layer cushions 9 in the base flange 6 are situated in each case closer to the adjacent tread edge, resulting in a different embedding stiffness of the stud 1 in a manner dependent on the predominantly acting loading direction. In the event of loading of the stud pin 3 in an axial or predominantly axial direction, as indicated in figure 7 by the arrow Pi, then the stud 1 is supported in the region of the non-cushioned base flange edge. Forces for good lateral guidance can thus be optimally transmitted. In the event of loading from the direction of the arrow P2, for example owing to slipping movements during the flattening-out of the tire, then the relatively soft embedding of the stud 1 in the region of the enveloping layer cushions 9 takes effect, and the stud 1 can deflect in a relatively pliant manner in the desired way.
In the embodiment shown in figure 8 to figure 14, the base part 4'a of the insert 4' is likewise an elongate oval component, but with narrow sides which are of unequal width in plan view and with identically designed longitudinal sides (figure 14). The stud 1' is of symmetrical design with respect to a plane of symmetry S2 (figure 11) running in the longitudinal extent of the base flange 4'a through the vertical axis a. At the narrow sides of the base part 4'a, there are situated arcuately outwardly rounded delimiting surfaces 8'ai and 8'a2. At the longitudinal sides, there are situated delimiting surfaces 8'b which run in a concavely inwardly curved manner. Straight lines which connect the ends of the delimiting surfaces 8'b run in each case at an acute angle 7, of the order of magnitude of 50 to 200 , with respect to the plane of symmetry S2, such that the spacing of said straight lines to one Date Recue/Date Received 2020-07-13

12 another at their ends at the delimiting surface 8'ai is smaller than the spacing of said straight lines to one another at their ends at the delimiting surface 8'a2. The delimiting surfaces 8'ai and 8'a2 are, in each case in the region of their rounding centers, equipped with a flattened portion 12ai and 12a2 which runs in a straight manner in plan view. Said portions 12ai and 12a2 run at right angles to the plane of symmetry S2. The portion 12ai is shorter by 0.3 mm to 0.8 mm than the portion 12a2, the length of which is of the order of magnitude of 2.0 mm to 3.0 mm. The enveloping layer 5' surrounds the delimiting surfaces 8'ai and 8'a2 unifoinily and in each case overall in an outwardly rounded manner and, at the rounded portions of the delimiting surfaces 8'ai and 8'a2, with a constant or substantially constant layer thickness d3, da. The layer thickness d3 of the enveloping layer 5' along the rounded portions of the relatively short delimiting surface 8'ai may however also be smaller than that along the rounded portions of the relatively long delimiting surface 8'a2. In any case, a larger and thicker enveloping layer cushion 9' is formed along the flattened portion 12a2 at the relatively long delimiting surface 8'a2 than along the portion 12ai at the delimiting surface 8'ai. The thickness ds of said enveloping layer cushion 9' at the flattened portion 12a2 amounts to 0.5 mm to 1.0 mm. Along the delimiting surfaces 8'b, which run in a concavely inwardly curved manner, of the base part 4'a, the enveloping layer 5' is formed preferably with a planar outer surface and therefore with a correspondingly varying layer thickness d6 of 0.2 mm to 0.4 mm.
The stud pin 3', which is positioned in the center of the stud 1' along the vertical axis a, has a top surface 7' which approximately the form of an elongate rectangle with beveled corners and a length 13 of 2.8 mm to 3.2 mm and a width b3 of 1.8 mm to 2.0 mm, wherein the stud pin 3' is anchored in the insert 4' so as to extend at right angles to the plane of symmetry S2 and thus so as to be symmetrical in relation thereto. The top surface 7' therefore has two relatively long grip edges 13ai and 13a2, which run at right angles to the plane of symmetry S2, and furthermore two relatively short grip edges 13b which run parallel to the plane of symmetry S, and which are of equal length. The grip edges 13b have in particular an extent length of 1.0 mm to 1.7 mm, the grip edge 13ai has a length of 2.3 mm to 3.2 mm, and the grip edge 13a2 has a length which is shorter by up to 1.2 mm than the length of the grip edge 13ai. Corner edges 14a connect the grip edge 13ai to the grip edges 13b, and corner edges 14b connect the grip edge 13a2 to the grip edges 13b. Situated in an adjoining manner Date Recue/Date Received 2020-07-13

13 along the extent of the stud pin 3' are side surfaces which proceed from the grip edges 13at, 13a2, 13b and the corner edges 14a, 14b and which are designed correspondingly and which are not designated. Instead of corner edges and associated corner surfaces, the stud pin 3' may have transition roundings and rounded transition surfaces.
The stud 1' is a so-called traction and braking stud, which is preferably provided in all stud tracks of a tread, in particular in combination with studs 1. In the case of treads of non-directional design, approximately half of the studs 1' which are provided in the tread are - in a manner correspondingly distributed over the circumference - arranged with an orientation with respect to the circumferential direction (arrow U in figure 11) as illustrated in the figures, and the second half of the studs 1' which are provided are arranged with an opposite orientation. What is particularly advantageous, however, is the arrangement of the studs 1' in treads of tires with a predefined direction of rotation during forward travel, that is to say in tires with a tread which is of directional design. Here, the studs 1' are arranged such that, as the tire rolls during forward travel, the wider side of the base flanges 6' points in the rolling direction, as indicated by the arrow U in figure 11. Such an arrangement of the studs 1' is particularly advantageous for the embedding stiffness in the case of forces which act under traction loading and braking loading on icy underlying surfaces.
Under traction, the stud pin 3' of the stud 1' easily engages with its relatively short grip edge 13a2 into the ice surface and commences the transmission of force; in the process, it is tilted and is supported in a stiff manner on the relatively narrow enveloping layer cushion 9.
The front, relatively thick enveloping layer cushion 9' facilitates the tilting of the stud, because the elastic rubber material has a lower stiffness than the plastics or aluminum material of the base part 4'a. In this way, the stud 1' can easily "stand upright" in order to form a greater projecting length and in order to more quickly assume the optimum cutting angle.
During the transmission of braking force, the stud pin 3' also initially engages with its relatively short grip edge 13a2 into the ice, but is then "tipped over owing to the relative movement between tire and road surface, and then transmits the braking forces by way of its relatively long grip edge 13ai. During the "tipping over" of the stud, the pin 3' is, in Date Recue/Date Received 2020-07-13

14 effect, automatically pressed into the ice. To maximize the braking forces, it is particularly important for the stud 1' to be embedded in a flexible manner in order that stress peaks are dissipated and thus premature ice breakage is prevented. The flexible embedding is realized by means of the relatively thick, elastic enveloping layer cushion 9' on the base flange 6'.
Figure 15 schematically shows a circumferential portion of a tread for a passenger motor vehicle winter tire with a directional profile. The tread shown by way of example has two shoulder-side profile block rows 15 and, between these, in the central tread region, further profile blocks 16 which are formed by transverse channels 17 running in a V
shape over the width of the tread and by a number of circumferential channels 18 and oblique channels 19.
The direction of rotation during forward travel is denoted by an arrow P. B
denotes the width of that part of the tread which makes contact with the ground. Within this width B, the studs 1, l' are arranged in so-called stud tracks Sp, the number of which normally amounts to between 4 and 25, in particular 12 and 20. Stud tracks Sp are lines running in a circular encircling manner parallel to the circumferential direction, and are represented in figure 15 by dashed lines. In the embodiment shown in figure 15, seven stud tracks Sp are provided in each tread half, the arrangement of which is symmetrical in relation to the tire equator A-A.
In the circumferential portion shown at least one stud 1 and at least one stud 1' are shown in each stud track by way of example. Normally, 4 to 25, in particular 7 to 16, studs 1, 1' are positioned over the circumference of the tire in each stud track Sp. In an alternative embodiment, exclusively studs 1 are positioned in the stud tracks Sp in the two lateral circumferential regions, and exclusively studs 1' are positioned in the stud tracks Sp in the central circumferential region.
Date Recue/Date Received 2020-07-13 List of reference designations 5 ......... 1,1' Stud 2, 2' ......... Stud body 2a ............ Stud body part 3,3' .......... Stud pin 4, 4' ......... Insert 10 ........ 4a, 4'a Base part 4b, 4'b ....... Pin holder 5, 5' ......... Enveloping layer 6, 6' ......... Base flange 7, 7' ......... Top surface

15 8a, 8b Delimiting surface 8'a2 .......... Delimiting surface 8'b ........... Delimiting surface 8ci, 8c2 ...... Delimiting surface 9, 9' ......... Enveloping layer cushion ........ 10al, 10a2 Grip edge 11a2 .......... Grip edge 12ai, 12a2 .... Portion 13a2 .......... Grip edge 13b ........... Grip edge ........ 14a, 14b Comer edge 15 ............ Profile block row

16 ............ Profile block

17 ............ Transverse channel

18 Circumferential channel

19 Oblique channel ct, 0, y ...... Angles AA ............ Tire equator nate Regue/Date Received 2020-07-13 a ............. Vertical axis .............. Width bi, b2, h3 .... Width 11,12,13 ...... Length ......... di, d2 Thickness d3, da, d5, d6 .. Thickness Pi, P2 ........ Arrow Pv ............ Arrow Si, S2 ........ Plane of symmetry ........ SP Stud track Date Recue/Date Received 2020-07-13

Claims

Patent claims

1. A stud for anchoring in a stud hole of a tread of a pneumatic vehicle tire, having a stud body which is composed of a nonmetallic, elastic material, and which comprises a base flange, and having a stud pin, which stud pin is composed of hard metal and is anchored in an insert which is situated within the stud body and which comprises a base part, and which stud pin projects with an end portion beyond the stud body, wherein the base part together with an enveloping layer composed of the material of the stud body forms the base flange of the stud body, and wherein the base flange has an outer contour which is designed symmetrically with respect to at least one plane of symmetry and which has two longitudinal sides and two narrow sides, characterized in that the outer contour of the base part differs geometrically from that of the base flange, such that the enveloping layer has, at that side of the base part which is assigned to a longitudinal side and/or to a narrow side, at least one portion in which said enveloping layer is thicker than at the opposite side of the base part.

2. The stud as claimed in claim 1, characterized in that the stud body is composed of rubber material.

3. The stud as claimed in claim 1 or 2, characterized in that the portion in which the enveloping layer has a relatively large thickness forms an enveloping layer cushion.

4. The stud as claimed in any one of claims 1 to 3, characterized in that the base flange has outer surfaces which, in plan view, run in a straight manner along the longitudinal sides of said base flange and run in an outwardly curved manner along the narrow sides of said base flange.

5. The stud as claimed in any one of claims 1 to 4, characterized in that the base part has longitudinal and narrow sides which are assigned to the longitudinal and narrow sides of the base flange and which have outwardly rounded delimiting surfaces at the narrow sides and, along one longitudinal side, two delimiting surfaces which run at an obtuse internal angle with respect to one another, such that the enveloping layer forms, to the outer surface of the base flange, two enveloping layer cushions.

6. The stud as claimed in claim 5, wherein the two enveloping layer cushions are triangular in plan view.

7. The stud as claimed in claim 5 or 6, characterized in that the obtuse internal angle between the delimiting surfaces amounts to 1500 to 170 .

8. The stud as claimed in claim 5 or 6, characterized in that the enveloping layer cushions have a greatest thickness of 0.35 mm to 1.0 mm.

9. The stud as claimed in claim 5 or 6, characterized in that the enveloping layer cushions have a greatest thickness of 0.7 mm to 1.0 mm.

10. The stud as claimed in claim 8 or 9, characterized in that the enveloping layer has, along those longitudinal and narrow sides of the base part at which no enveloping layer cushion is formed, a thickness which is smaller than the greatest thickness of the enveloping layer cushion(s).

11. The stud as claimed in any one of claims 1 to 10, characterized in that the end portion of the stud pin is elongate transversely with respect to the longitudinal sides of the base flange and of the base part and has two grip edges which extend in the direction of the longitudinal sides and which are of unequal length, wherein the longer grip edge is that which is closer to the longitudinal side at which the enveloping layer cushion(s) is or are formed.

12. A pneumatic vehicle tire having a tread with studs as claimed in any one of claims 1 to 11, characterized in that the studs are positioned in the tread such that, in each tread half, the enveloping layer cushions in the base flange are situated in each case closer to the adjacent tread edge.

13. The stud as claimed in any one of claims 1 to 4, characterized in that the base part has longitudinal and narrow sides which are assigned to the longitudinal and narrow sides of the base flange and which have outwardly rounded delimiting surfaces at the narrow sides, wherein at least one of said delimiting surfaces is, in the region of a corresponding rounding center, equipped with a flattened portion which runs in particular in a straight manner in plan view, such that the enveloping layer forms an enveloping layer cushion to the outer surface of the base flange.

14. The stud as claimed in claim 13, characterized in that the narrow sides of the base flange and of the base part are of unequal width, wherein the base part is, at least at a wider narrow side, in the region of the rounding center, equipped with a flattened portion which runs in a straight manner in plan view.

15. The stud as claimed in any one of claims 13 or 14, wherein the flattened portion has a length of 2.0 mm to 3.0 mm.

16. The stud as claimed in any one of claims 13 to 15, characterized in that the enveloping layer cushion has a greatest thickness of 0.5 mm to 1.0 mm, in particular 0.7 mm to 1.0 mm.

17. The stud as claimed in any one of claims 13 to 15, characterized in that the enveloping layer cushion has a greatest thickness of 0.7 mm to 1.0 mm.

18. The stud as claimed in any one of claims 13 to 17, characterized in that each of the outwardly rounded delimiting surfaces is, at the narrow sides, in the region of its rounding center, equipped with a second flattened portion which runs in a straight manner in plan view, wherein the enveloping layer cushion at the narrow side with the greater width has a greater thickness at its thickest point than the enveloping layer cushion at the narrow side with the smaller width.

19. The stud as claimed in any one of claims 13 to 18, characterized in that the base part has, at its longitudinal sides, delimiting surfaces which run in a concavely inwardly curved manner.

20. The stud as claimed in claim 19, characterized in that the enveloping layer has, at the delimiting surfaces which run in a concavely inwardly curved manner, outer surfaces which run in a straight manner in plan view and a varying layer thickness of 0.2 mm to 0.4 mm.

21. The stud as claimed in any one of claims 1 to 3 or 13 to 20, characterized in that the end portion of the stud pin is, in plan view, elongate transversely with respect to the longitudinal sides of the base flange and of the base part and has grip edges of unequal length in relation to the narrow sides of the base part, wherein the shorter grip edge is that which is situated closer to the enveloping layer cushion at the narrow side or, if enveloping layer cushions are formed at both narrow sides, to the thicker enveloping layer cushion.

22. A pneumatic vehicle tire having a tread with studs as claimed in any one of claims 1 to 3 or 13 to 21, characterized in that the studs are positioned in the tread such that the enveloping layer cushion(s) is or are assigned to, or face(s) toward, the circumferential direction of the tire.