-1- 3917791 Pneumatic tyre Description
[0001] The invention relates to a pneumatic vehicle tyre having a tread comprising profile elements with spikes, which each have a spike body anchored in a profile element and a spike pin positioned therein, wherein spikes of a first type and of a second type, which differ from one another at least in the design of their spike pins, are provided, wherein the spikes of the first type bring about better lateral force transmission than the spikes of the second type, which bring about better circumferential force transmission than the spikes of the first type.
[0002] It is known that the general mode of action of spiked tyres is based on a number of effects. Firstly, spikes penetrate into, and mechanically mesh with, ice situated on the roadway. During braking and traction processes, relative movements (slippage) furthermore occur between the pneumatic vehicle tyre and the ice-covered roadway, during which the spikes are pulled through the ice and in the process cut channels into the ice surface. The ice particles - ice chips or ice powder - formed in the process commonly collect around the respective spike, as a result of which both the ice grip action of the spike and the ice grip action of the rubber material of the tread surrounding the spike deteriorate.
[0003] To counteract the adverse effects of the ice particles that form, it is known for shallow depressions to be provided in the immediate vicinity of the spike as "ice reservoirs" for receiving the ice particles. Such ice reservoirs are known in a variety of embodiments.
[0004] A pneumatic vehicle tyre of the type mentioned at the outset is disclosed for example by WO 2018/210460 A1. The tread of the tyre is thus provided with spikes of a first and of a second type. The spikes of the first and second type differ from one another in the design of their spike pins, wherein the spikes of the first type bring about better lateral force transmission and spikes of the second type bring about better braking and traction force transmission. In this case, the spikes are arranged in spike tracks which run around the circumference
-2- 3917791 of the tread and in which both spikes of the first type and spikes of the second type are provided. By this means, the handling properties of the pneumatic vehicle tyre are optimized.
[0005] A pneumatic vehicle tyre with a tread that has spikes and depressions acting as ice reservoirs is known from DE 10 2014 225 047 Al, for example. In plan view, the depressions are elongate, extend in the circumferential direction and have a main section extending over the majority of their circumferential extent and an end section adjoining said main section. In the main section, the width and depth of the depressions increases with increasing distance from the spike. In the end section, the width and depth of the depressions decreases with increasing distance from the spike. When driving on smooth ice, the function of these depressions as ice reservoirs is maintained since the ice particles can be conveyed unhindered from the spike into the regions of the depressions with a larger cross-sectional area.
[0006] WO 2017/071842 A1 discloses a pneumatic vehicle tyre having a tread of directional design that is provided with spikes and has profile blocks and depressions acting as ice reservoirs. Elongate depressions of different volumes and different lengths of extent extending at least in the two circumferential directions are formed in the profile block around each spike. The depression(s) that extends (extend) from the spike in the rolling direction during forward travel has (have), in sum total in the case of multiple depressions, the greatest volume. At least one further depression is preferably formed on each spike, said depression extending axially outward in the direction of the tyre shoulder situated closer to the spike and having the smallest volume, in sum total in the case of multiple depressions. By virtue of these measures, the volumes of the depressions are matched to the amounts of ice chips that form as a result of the different relative movements between spike and ice-covered roadway.
[0007] FI 126308 B discloses a pneumatic vehicle tyre having a tread which has a central tread region and two lateral tread regions, wherein spikes of a first type are anchored in the central tread region, said spikes effecting better braking and
-3- 3917791 traction force transmission than spikes of a second type, which are anchored in the two tread regions at the shoulders. The spikes of the two types differ in respect of the cross section and cross-sectional area of their spike pins.
[0008] DE 10 2016 212 280 Al discloses a pneumatic vehicle tyre having a tread comprising profile block rows at the shoulders and a central tread region, wherein spikes of a first type are used in the profile block rows at the shoulders and spikes of a second type are used in the central tread region. The spikes have spike pins with circumferential gripping edges, wherein the contour profile of the gripping edge of the spike pin of the spike of the first type differs from the contour profile of the gripping edge of the spike pin of the spikes of the second type such that the spike pin of the spike of the first type has a first length projecting in the circumferential direction and the spike pin of the spike of the second type has a second length projecting in the circumferential direction, wherein the first length is greater than the second length. The spike of the first type therefore has better lateral force transmission than the spike of the second type.
[0009] In order to enhance the advantageous effects of spikes on the driving characteristics of a tyre, it is therefore known, in particular, to form depressions acting as ice reservoirs in the region of the spikes or to provide the tread with spike types that act differently - in respect of force transmission to the underlying surface - differing, in particular, in the geometry of their spike pins.
[0010] If the depressions acting as ice reservoirs cannot receive the full amount of ice chips that form, the ice chips collect between the tread and the roadway, as a result of which the meshing of the spikes with the ice does not function optimally, and the ice grip accordingly deteriorates. On the other hand, an unduly large volume of the depressions provided has an adverse effect on the ice grip characteristics of the profile positives of the tread, because depressions of excessively large area significantly reduce the rubber surface of the profile elements.
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[0011] It is the underlying object of the invention to make available a pneumatic vehicle tyre which has a tread provided with spikes and the grip and driving characteristics of which are additionally and significantly improved.
[0012] The stated object is achieved in that depressions for receiving the ice particles created when the spikes scratch ice are formed in the profile elements in the immediate vicinity of the spikes, wherein the depressions in the case of spikes of the first type differ from the depressions in the case of spikes of the second type in their shape and/or their position relative to the spike such that, when driving on ice, the depressions in the case of the spikes of the first type increasingly receive the ice particles occurring under the influence of lateral forces and the depressions in the case of the spikes of the second type increasingly receive the ice particles occurring under the influence of circumferential forces, wherein, in the case of spikes of the first type, lateral depressions which are formed in the region of the side of the spike which lies closer to the tyre shoulder are provided, and wherein, in the case of spikes of the second type, depressions which are situated in circle sectors which lie diametrically opposite one another, being separated from one another by the respective spike, and extend over a central angle, with respect to the principal axis of the spike, which is +/- 35° relative to the circumferential direction are provided.
[0013] In the case of a pneumatic vehicle tyre embodied in accordance with the invention, spikes of a first type and spikes of a second type are provided in the tread. The spikes of the first type effect better lateral force transmission than the spikes of the second type, which effect better circumferential force transmission,
i.e. better transmission of braking and traction forces, than the spikes of the first type. According to the invention, the arrangement and/or configuration of the depressions provided in the case of the two spike types is matched to the respective spike type in a particularly advantageous manner. The depressions in the case of the spikes of the first type are arranged in such a way that they receive more of the ice particles forming under the influence of lateral forces and the depressions in the case of the spikes of the second type are arranged in such a
-5- 3917791 way that they receive more of the ice particles forming under the influence of circumferential forces. A tyre according to the invention therefore has spikes with different mechanisms of action and depressions which are matched to these mechanisms of action in a particularly advantageous manner and act as ice reservoirs, thereby significantly improving the ice grip characteristics of the tyre in comparison with the known embodiments.
[0014] According to a preferred design variant, the respective depression(s) which is (are) formed in the case of a spike of the first type has (have) a larger volume, in the case of a plurality of depressions in total, than the depression(s) which is (are) formed in the case of a spike of the second type. This measure is advantageous, in particular, because, in the case of spikes of the first type, there is a tendency for more ice particles to form than in the case of spikes of the second type.
[0015] According to another preferred design variant, spikes of the first type are provided on which the spike pin is elongate in plan view and has a plane of symmetry which is aligned in the longitudinal extent of said pin and extends at an angle of 0° to 20° to the axial direction, wherein the plane of symmetry of the spike pin is preferably simultaneously the plane of symmetry of at least one depression formed in the immediate vicinity of the associated spike. By virtue of this "double-symmetrical" configuration, the "interaction" between the spike pin and the depression is further improved in respect of the effectiveness of the depressions under the influence of the lateral guiding forces.
[0016] This interaction is then further improved if, in this preferred design variant, at least one depression is provided which is situated within a circle sector which is formed symmetrically with respect to the plane of symmetry of the spike pin and which extends over a central angle of 70° with respect to the principal axis of the associated spike.
[0017] There is furthermore a preference for an embodiment in which two depressions are formed in the immediate vicinity of each of the spikes of the first
-6- 3917791 type, said depressions lying diametrically opposite one another, being separated from one another by the respective spike, wherein the plane of symmetry of the spike pin is simultaneously the plane of symmetry of the two depressions. By means of this measure, the ice particles that form under the influence of lateral guiding forces are taken up in a particularly reliable manner.
[0018] It is likewise advantageous if precisely one depression is formed in the immediate vicinity of each of the spikes of the first type, said depression being situated within a circle sector which extends symmetrically with respect to the plane of symmetry of the respective spike pin and over a central angle of 180° with respect to the principal axis of the spike, and wherein the depression itself extends over a central angle of at least 120°, in particular of at least 160°, and preferably of 180°. A depression embodied in this way has a relatively large "catchment area" for the ice particles which form.
[0019] According to another preferred design variant, spikes of the first type are provided on which the spike pin is elongate in plan view and has a plane of symmetry which is aligned in the longitudinal extent of said pin and extends at an angle of 0° to 20° to the axial direction, wherein depressions are formed in the immediate vicinity of the spikes, said depressions lying diametrically opposite one another, being separated from one another by the respective spike, and, in plan view, preferably having a plane of symmetry which is perpendicular to the plane of symmetry of the spike pin. It is thereby possible to further improve the ice grip action of the spikes of the first type.
[0020] It is particularly advantageous if, in this design variant, the tread has profiling of directional design, wherein the depression(s) which encounters (encounter) the underlying surface first as the tyre rolls during forward travel is (are) at a shorter distance from the tyre eguatorial plane (A-A) than the diametrically opposite depression(s).
[0021] Itis additionally advantageous here if, in the case of the spikes of the second type, the depressions provided are exclusively depressions which are situated in
-7- 3917791 the circle sectors, wherein these depressions preferably lie diametrically opposite one another, being separated from one another by the spike.
[0022] Another preferred design variant is characterized in that spikes of the second type are provided on which the spike pin is elongate in plan view and is oriented in the axial direction and has a plane of symmetry which is aligned in the circumferential direction and is preferably simultaneously the plane of symmetry of the depressions formed in the respective spike. By virtue of this "double- symmetrical" configuration, the interaction between the spike pin and the depression is further improved in respect of the effectiveness of the depressions under the influence of the circumferential forces.
[0023] An advantageously configured pneumatic vehicle tyre having particularly good ice grip characteristics - both under the action of lateral forces and under the action of circumferential forces - is characterized in that the spikes are distributed over the circumference of the tread in such a way that in each case at least two spikes of the first type and at least two spikes of the second type are situated in the contact patch during the rolling of the tyre.
[0024] In this context, it is furthermore advantageous if the spikes are distributed over the circumference of the tread in such a way that the ratio of the number of spikes of the first type to the number of spikes of the second type within the ground contact area is 1:1 to 1:3.
[0025] According to another preferred design variant, spikes of the second type are provided on which the spike body has an upper side interrupted by two recesses, wherein the recesses lie opposite one another, being separated by the spike pin, and wherein the spike is preferably inserted in the tread in such a way that the recesses are associated in plan view with the depressions formed in the immediate vicinity of the spike. Such recesses formed on the spike body on the one hand act themselves as ice reservoirs and, on the other hand, promote the removal or transfer of the ice chips into the associated depressions.
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[0026] Further features, advantages and details of the invention will now be described in more detail with reference to the drawing, which schematically shows an exemplary embodiment of the invention. In the figures: Figure 1a shows a plan view of a spike of a first type, Figure 1b shows a scaled-down side view of the spike from figure la according to the direction of view indicated by the arrow Pip, Figure 1c shows a scaled-down side view of the spike from figure la according to the direction of view indicated by the arrow Pic, Figure 2a shows a plan view of a spike of a second type, Figure 2b shows a scaled-down side view of the spike from figure 2a according to the direction of view indicated by the arrow Pap, Figure 2c shows a scaled-down side view of the spike from figure 2a according to the direction of view indicated by the arrow P2c, Figure 3 shows a plan view of a detail of a tread of a pneumatic vehicle tyre having spikes of both types, Figure 3a shows an enlarged plan view of a detail of the tread from figure 3 in the region of a spike of the first type, Figure 3b shows an enlarged plan view of a detail of the tread from figure 3 in the region of a spike of the second type, Figure 4a shows an enlarged plan view of a detail of the tread in the region of a spike of the first type according to a first further variant, and Figure 5a shows an enlarged plan view of a detail of the tread in the region of a spike of the first type according to a second further variant.
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[0027] Pneumatic vehicle tyres embodied in accordance with the invention are, in particular, tyres of radial design for passenger cars, vans or light trucks, which are particularly well suited to driving under winter driving conditions. The invention is concerned with spikes of two different spike types, which are anchored in profile elements of the tread, and with depressions which are formed in the immediate vicinity of the spikes and which serve as discharge channels or reservoirs for the ice particles which form when driving on ice. One spike type is configured, in particular, with a view to good lateral force transmission, while the other spike type is configured, in particular, with a view to good circumferential force transmission, i.e. good transmission of braking and traction forces, as described in greater detail below.
[0028] Figure la to figure 1c show views of a preferred design variant of a spike 1 of a first type. Figure 2a to figure 2c show similar views of a preferred design variant of a spike 2 of a second type. The position of the principal axis ai of the spikes 1, 2, which extends in the vertical direction when the spike is upright, is indicated by an arrow in figure la and figure 2a.
[0029] As figure la to figure 1c and figure 2a to figure 2c show, the spike 1, 2 comprises a spike body 3 and a spike pin 4 (spike 1), 5 (spike 2) anchored in said body. In the exemplary embodiment shown, the spike body 3 has a base flange 3a, a waisted central part 3b (figure 1b, figure 1c, figure 2b, figure 2c) and an upper flange 3c. The central part 3b and the upper flange 3c are at least substantially rotationally symmetrical, the base flange 3a has a substantially oval shape in plan view (figure la, figure 2a) and two flat lateral surfaces 3a' (figure la, figure 2a) extending parallel to one another in the longer direction of extent of the oval, and two mutually opposite rounded lateral surfaces 3a" (figure la, figure 2a). As figure la and figure 2a show, the base flange 3a has a plane of symmetry Fi aligned in the longitudinal extent thereof and extending parallel to the flat lateral surfaces 3a' and through the principal axis ai of the spike 1, 2, as well as a second plane of symmetry E2, which extends through the principal axis a1 and orthogonally to the plane of symmetry Ei.
- 10 - 3917791
[0030] Spike pin 4 and spike pin 5 are elongate components in plan view, with a maximum length 11 and a maximum width bi, wherein Ii > bi and wherein the spike pin 4, 5 is anchored in the spike body 3 in such a way that it is elongate in the direction of extent of the second plane of symmetry Ez in plan view. Both spike pin 4 and spike pin 5 have, on the upper side thereof, a so-called abrasion protection dome 6, which is not the subject matter of the invention and can be embodied in a conventional manner.
[0031] As figure la shows, spike pin 4 is symmetrical with respect to the already mentioned plane of symmetry Ez, and therefore said plane is simultaneously a plane of symmetry of spike pin 4. In plan view, spike pin 4 has the shape of two isosceles trapezoids joined together at their base and having different heights, wherein the point with the maximum width bi is located at the common basis of the trapezoid and wherein this point is offset to the left in figure 1a by a distance az with respect to the plane of symmetry Fi. On its outer circumference, spike pin 4 has two gripping edges 4a, 4a' extending perpendicularly to the plane of symmetry E2 and furthermore two gripping edges 4b, which form the trapezoid sides of the trapezoid with the smaller height, and two gripping edges 4b', which form the trapezoid sides of the trapezoid with the greater height. Gripping edge 4a is closer to the broadest side of spike pin 4 than gripping edge 4a' and has a length l4a which is 0.1 mm to 0.3 mm greater than the length l4x of gripping edge
4a'. The width bi of spike pin 4 is 0.1 mm to 0.3 mm greater than the length l4a of gripping edge 4a. Each gripping edge 4b encloses an obtuse angle with the respective gripping edge 4b', wherein their intersections are at the already mentioned distance ax from the plane of symmetry Ei and at a distance as of preferably 60% of the length 11 from gripping edge 4a'.
[0032] As figure 2a shows, the spike pin 5 of the spike 2 of the second type is symmetrical with respect to the already mentioned plane of symmetry Ei, and therefore said plane is simultaneously a plane of symmetry of spike pin 5. In plan view, spike pin 5 is almost rectangular, wherein the corner regions are beveled. On its outer circumference, spike pin 5 has two straight gripping edges Sa of equal length extending parallel and symmetrically with respect to the plane of
- 11 - 3917791 symmetry Ei and two straight gripping edges 5b, 5'b of unequal length oriented perpendicularly to the plane of symmetry Ei. The maximum length 11 of spike pin 5 is determined by the mutual spacing of the gripping edges Sa, while the maximum width bi of spike pin 5 is determined by the mutual spacing of the gripping edges Sb and 5'b. The two gripping edges Sa have a length Isa which is less than the lengths lsh, 15v of the gripping edges Sb, 5'b, wherein, in the embodiment shown, the length Is» at the gripping edge 5'b at the bottom in figure 2a is 0.5 mm to 1.0 less than the length 15 of the gripping edge 5b at the top in figure 2a.
[0033] The upper flange 3c of the spike 2 of the second type has an upper side 9 which is interrupted by two recesses 7, 8 and is otherwise flat and extends parallel to the base flange 3a, or to the upper side thereof, respectively, said upper side 9 being delimited on the outside by narrow edge sections 9a which extend so as to slope downward obliquely in the direction of the base flange 3a. In plan view, the recesses 7, 8 are each symmetrical with respect to the plane of symmetry Ei and are therefore offset by 180° relative to one another with respect to the principal axis a1 and thus lie opposite one another, being separated by spike pin 5. Furthermore, the recesses 7, 8 extend from spike pin 5 to the edge of the upper flange 3c, at which they end as open recesses and each have a depth of 0.5 mm to 2.0 mm determined parallel to the principal axis ai. In plan view, each recess 7, 8 is substantially U-shaped and is bounded by two flat boundary walls 10, each forming one leg of the U shape and extending as far as spike pin 4. In plan view, the boundary walls 10 of recess 7 extend at an angle a of, in particular, up to 20° to the plane of symmetry Ei, wherein, starting from spike pin 4, recess 7 becomes continuously wider in the direction of its open end at the edge of the upper flange 3c. In plan view, the boundary walls 10 of recess 8 extend substantially parallel to the plane of symmetry Ei. The volume of recess 8 is greater than the volume of recess 7, wherein the different volumes are advantageous for their function as ice reservoirs.
[0034] Figure 3 shows a circumferential segment of a tread provided with a multiplicity of spikes 1, 2 and having directional profiling, wherein the
- 12 - 3917791 pneumatic vehicle tyre should be mounted on the vehicle in such a way that it has the rolling direction symbolized by the arrow R when moving forward. The equatorial plane of the tyre is indicated by a dashed line A-A, and the circumferential direction is indicated by a double arrow U.
[0035] The tread, which is shown purely by way of example, has profile blocks 11, which are bounded by obligue grooves 12 extending in a V shape across the width of the tread and by short grooves 13 extending between said obligue grooves.
[0036] In the exemplary embodiment shown, the spikes 1, 2 are distributed over the circumference of the tread in such a way that, as the tyre rolls, at least two spikes 1 and at least two spikes 2 are always situated in each ground contact area established with the underlying surface, i.e. in the "contact patch", wherein the ground contact area corresponds to the statically determined footprint (determined with a tyre mounted on a standard rim, load at 70% of the maximum load capacity, internal pressure 85% of standard pressure, in accordance with ETRTO standards). There are preferably at least two spikes 1 and at least two spikes 2 in the contact patch in each tread half. It is furthermore preferred if the ratio of the number of spikes 1 of the first type to the number of spikes 2 of the second type in the contact patch is 1:1 to 1:3.
[0037] As figure la in combination with figures 3 and 3a shows, the spikes 1 of the first type are inserted into the tread in an orientation such that the plane of symmetry Ez extends at an angle B of 0° to 20°, in particular of 5° to 15°, to the axial direction, wherein the gripping edges 4b which form the trapezoid sides of the trapezoid with the smaller height encounter the underlying surface before the respective subsequent gripping edge 4b' as the tyre rolls during forward travel. Particularly preferably, the spikes 1 are inserted into the tread in such a way that that one of the two gripping edges 4b which encounters the underlying surface first as the tyre rolls during forward travel is oriented in the axial direction.
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[0038] The spikes 1 are therefore preferably positioned in such a way that the spikes 1 have a mutually opposite slope of the planes of symmetry Ei, F2 in one tread half as compared with the spikes 1 in the other tread half, based on the tyre circumferential direction (figure 3).
[0039] As figure 3a, in particular, furthermore shows, three superficial depressions 14, 15, 16, which serve as ice reservoirs, are formed in the respective profile block 11 around the spike 1 in the exemplary embodiment shown. The depressions 14 and 15 are each situated within a circle sector KS1 of symmetrical design with respect to the plane of symmetry Ei (shown only for depression 15), wherein the two circle sectors KS: are situated diametrically opposite one another while being separated by the spike 1 and each extend over a central angle y of 70° in relation to the principal axis ai of the spike 1. Furthermore, the depressions 14, 15 are embodied in a symmetrical manner with respect to the plane of symmetry EFi and elongate in the direction of extent of the plane of symmetry Ei, wherein depression 14 encounters the underlying surface before depression 15 as the tyre rolls during forward travel. Depression 16 is situated on the side of the spike 1 which is closer to the tyre shoulder and within a circle sector KS2 which is of symmetrical design with respect to the plane of symmetry FE? and extends over a central angle ö of 70° with respect to the principal axis ai of the spike 1. Furthermore, depression 16 is of symmetrical design with respect to the plane of symmetry Ez. In plan view, the depressions 14, 15, 16 each have a deltoid-like shape. The volume of depression 14 is greater than that of depression 15, which has a volume that is greater than that of depression 16. A similar statement applies to the lengths of extent of depressions 14, 15, 16 determined in planes of symmetry Ei, Ea.
[0040] As figure 2a in combination with figures 3 and 3b shows, the spikes 2 of the second type are inserted into the tread with an orientation such that the spike pin 5 is aligned in the axial direction and the plane of symmetry Ei is aligned in the circumferential direction U, wherein the gripping edge 5'b of the spike pin 5 and depression 7 encounter the underlying surface before the gripping edge 5b of the spike pin 5 and depression 8 as the tyre rolls during forward travel. Gripping
- 14- 3917791 edge 5'b is therefore the "entering" gripping edge or "leading edge" and gripping edge 5b is the "exiting" gripping edge or "trailing edge".
[0041] As figure 3b, in particular, shows, two superficial depressions 17, which likewise serve as ice reservoirs, are formed in the respective profile block 11 around the spike 2, which depressions are situated in circle sectors KS3, lie diametrically opposite one another, being separated from one another by the spike 1, are symmetrical with respect to the plane of symmetry Ei and each extend over a central angle € of 70° with respect to the principal axis ai of the spike 1. The depressions 17 are, for example, likewise of deltoid-shaped design and are elongate in the direction of extent of the plane of symmetry Fi.
[0042] Figure 4a and figure Sa show variants of the depressions serving as ice reservoirs in the region of a spike 1 of the first type. The variant in figure 4a differs from that in figure 3a only in that a depression 16' is additionally formed in the case of spike 1, said depression being embodied in a manner similar to depression 16 and lying diametrically opposite the latter, being separated by the spike 1.
[0043] In the case of the variant shown in figure 5a, a depression 18 is formed in the case of spike 1 which is situated on that side of the spike 1 which is closer to the tyre shoulder and is formed within a circle sector KS4 which extends over a central angle 1 of 180° with respect to the principal axis a1 of the spike 1 and is embodied like a triangle in plan view, wherein the imaginary hypotenuse of the triangle passes through the principal axis ai of the spike 1. Depression 18 is preferably of symmetrical design with respect to the plane of symmetry Ea. Furthermore, depression 18 can have the shape of a circular ring segment in plan view.
[0044] The depressions 14, 15, 16, 16', 17, 18 have a depth of preferably 0.5 mm to
5.0 mm, in particular of up to 2.0 mm, at their deepest point.
[0045] The invention is not restricted to the design variants described and illustrated.
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[0046] The profiling of the tread of a tyre according to the invention may also not be of directional design. The profile elements of the tread can be profile blocks, profile strips or the like. The spikes and the depressions can have a shape that differs from the configuration described.
[0047] In the context of the substantive invention, a "depression formed in the immediate vicinity of the respective spike" is understood to mean a depression which adjoins the spike or is at a distance of at most 1.5 mm from said spike.
List of reference signs
Too. Spike VN) OTC
3.00 Spike body
3a......c.cccceieen.......... Base flange 3a',3a"........................ Lateral surfaces
3b.....cccceieieenen..... Central part IC Upper flange åsnen. Spike pin 4a, 4a',4b, 4b'............... Gripping edge Seen Spike pin Sa, 5b, 5b'.................... Gripping edge Oon ees. Abrasion protection dome
7,8. iii... Recess Q ieee Upper side Ianin Peripheral portion
10.............c..eceeon......... Boundary wall Ilona Profile block
12........................ Oblique groove
13... Groove 14, 15, 16, 16', 17, 18 .. Depression Alonen Principal axis A2, 83 coon. SPACING
A....................Double arrow (axial direction)
A-A.................... Line (tyre equatorial plane)
bl... Maximum width Ei, Ea... Plane of symmetry KSi:, KS2, KS3, KS4..... Circle sector dosen. Maximum length laa, laa’, 15a, Isp, 15b ......... Length Roineen. Arrow (rolling direction)
U...io......Double arrow (circumferential direction)
PB... Angle Y,0,&M..ccocen.o.......... Central angle