High-capacity tire

FIELD: transport.

SUBSTANCE: invention relates to vehicle tire tread design. High-capacity tire includes tread provided with four or five longitudinal grooves so that in axial direction they divide the tread into five or six ribs. Five or six ribs include a pair of ribs of shoulder area each one of which is provided with shoulder lateral groove, and three or four ribs of crown area each one of which is provided with lateral grooves of crown. Lateral grooves of crown pass throughout the crown area rib width. Shoulder lateral grooves pass axially outwards from axially-inner edge of shoulder area rib so that they end at axial distance of 78 to 88% of shoulder area rib axial width from the mentioned axially-inner edge. Depth of longitudinal grooves is 15 to 20 mm. Depth of lateral grooves of crown is 9 to 30% of longitudinal grooves depth. Depth of shoulder lateral grooves is 9 to 25% of longitudinal grooves depth. Tread width TW is 0.78 to 0.87 of tire cross-section width SW.

EFFECT: improved resistance to shoulder tire wear, as well as improved running characteristics of tire on wt road surface.

6 cl, 6 dwg, 1 tbl

 

The present invention relates to a pneumatic tire, more particularly to the configuration of the grooves of the tread of heavy-duty tires designed to improve the resistance of the shoulder tread wear and handling characteristics on wet road surface in the early stages of tread wear.

Heavy-duty tires such as winter tires and all terrain tires designed for off road use, usually provided with a tread pattern block type, consisting of independent units, separated from each other by the deep grooves of the projector. On the other hand, heavy tires, such as tires for trucks and buses, intended for driving on well-paved roads, usually provided with a tread rib type, consisting of a continuous in the longitudinal direction of the ribs because the ribs can withstand more load the tire than blocks. However, heavy tires with a picture of the projector in the form of ribs exposed to the so-called shoulder wear resulting from their relatively round profile of the tread and high load tires. In particular, the shoulder wear can occur leading to the front wheels, since a large friction energy is applied to the shoulder areas of the tread due to the centering of the front wheels, the movement of the front wheels �ri turn, relatively light load tires compared to the tires of the rear wheels, etc.

Thus, the aim of the present invention is to provide a heavy duty tire designated for use on well-paved roads, where the base of the tread pattern, consisting of five/six ribs, by providing a narrow cross grooves increase the rigidity of the axially outer edges of the shoulder areas of relatively axially internal edges of the area of the crown and as a result enhance resistance to shoulder wear and in addition improve driving characteristics on wet road surface at an early stage of wear of the tread.

In accordance with the present invention, a heavy duty tire comprises:

protector with the edges of the tread defining the width TW of the tread, a pair of sidewalls defining the width SW of the cross-section of the tire,

a pair of sides, each side with a ring inside,

a carcass extending between the sides through the tread and sidewall, and

belt belt consisting of a belt layer of the belt located radially outside of the carcass in the tread, where

the width TW of the tread is of 0.78 to 0.87 of the width SW of the cross-section of the tire,

the protector is equipped with four or five longitudinal grooves, each of which has a depth of from 15 to 20 mm and runs continuously � the longitudinal direction of the tire, what in the axial direction divides the tread into five or six ribs, these five or six ribs include a pair of ribs shoulder area, passing along the edges of the tread and provided with shoulder lateral grooves, and three or four ribs the crown area, located between the shoulder ribs and provided with transverse grooves of the crown,

the depth of the transverse grooves of the crown ranges from 9 to 30% of the depth of the longitudinal grooves,

the depth of the shoulder lateral grooves is from 9 to 25% of the depth of the longitudinal grooves,

these transverse grooves of the crown are spaced from each other in the longitudinal direction of the tire and passes through the entire width of the edges of the area of the crown, and

these shoulder transverse grooves spaced from each other in the longitudinal direction of the tire and passing axially outward from the axially inner edge of the shoulder rib area so that end at an axial distance from 78 to 88% of the axial width of the shoulder rib area from the specified axial inner edge.

Since the transverse grooves of the crown and shoulder transverse grooves shallow, the edges of the shoulder regions and the edge region of the corona is essentially retain the continuity in the longitudinal direction of the tire and as a result is able to withstand higher loads on the tire compared to the blocks. More then�about, shoulder transverse grooves end, not reaching the edges of the tread, therefore, the rigidity of the edges of the area of the crown is reduced more than the rigidity of the ribs, shoulder area, which improves the distribution of contact pressure, so that the energy of friction is aligned between the ribs of the shoulder areas and the edges of the area of the crown. Thus, the shoulder wear is reduced, without reducing the resistance to tread wear. Moreover, the driving characteristics on wet road surface, such as tire traction on wet road surface can be improved by the edges of the transverse grooves, and the drainage through the transverse grooves.

Here the width TW of the tread is an axial distance between the edges of The tread, measured in the normally inflated unloaded condition of the tire.

The edges of The projector are axially outer edge of the contact patch with the ground (the camber angle of the wheel=0) in a normally inflated unloaded condition.

The normally inflated unloaded state denotes a state in which the tire is mounted on a standard rim and inflated to normal internal pressure, but do not load standard load.

The normally inflated loaded condition denotes a condition in which the tire set n� standard rim and inflated to normal internal pressure and loaded with a standard load.

Standard rim means the rim of the wheel, officially adopted and recommended for the tire by standards bodies, i.e. JATMA (Japan and Asia), TRA (North America), ETRTO (Europe), TRAA (Australia), STRO (Scandinavia), ALAPA (Latin America), ITTAC (India) etc. who operate in the area where the tire is manufactured, sold and used.

Normal pressure and standard load tires are the maximum air pressure and the maximum load for the tires installed the same organizations in the table, the air pressure/maximum load or in these specifications. For example, the standard wheel rim is a standard rim" in the JATMA (Japan Association of manufacturers of automotive tires), "measuring rim" in the ETRTO (European technical organization rims and tires), "design rim" in the system TRA (Association for the rims and tires) or T. p. Normal internal pressure is the "maximum air pressure" in the system JATMA, the "pressure pump" in ETRTO, the maximum pressure specified in the table "Within loads of tyres at different pressures of the cold pumping system TRA or etc Standard load is the "maximum permissible load" in the system JATMA, the "allowable load" in ETRTO, the maximum value given in the above table TRA, etc.

In this application, including the description and the claims, various dimensions, positions, etc. are normally inflated unloaded condition of the tire unless otherwise noted.

The term "width" of the groove means a dimension measured perpendicular to the width of the Central line of the groove, unless otherwise indicated.

Brief description of the drawings

Fig.1 shows a cross sectional view of the heavy-load tire according to the present invention, showing the normally inflated unloaded state of the tire.

Fig.2 shows an enlarged cross sectional view of the tread of the tire.

Fig.3 shows a detailed partial top view supersize tire showing the tread.

Fig.4 is a partial top view of the protector showing the edge of the shoulder area.

Fig.5 shows a top view of the protector showing the edge region of the corona.

Fig.6 shows a detailed partial top view supersize bus used in the following comparative tests as a comparative example CP.1.

Description of the preferred embodiments

When considering radial tyres for trucks/buses as an example of an embodiment of the present invention is described hereinafter in detail in conjunction with the accompanying drawing�mi.

In accordance with the present invention the heavy-load tire 1 comprises a tread 2, a pair of sidewalls 3, a pair of sides 4, each with side rings 5 inside the carcass 6 extending between the flanges 4 through the tread 2 and the sidewalls 3, and belt belt 7 located outside of the carcass 6 in the tread 2 to accentuate the protector 2 essentially over its entire width.

The carcass 6 comprises at least one (in this example only one) layer 6A cords of the carcass arranged radially at an angle of 75 to 90 degrees relative to the equator With tires that passes between the flanges 4 through the tread 2 and the sidewalls 3 and is bent around the bead core 5 in each side from the inner side to the outer side of the tire, forming a couple of creases layer 6b of the carcass main portion 6A of the layer of the carcass between them. In this example, use steel cords as the cords of the carcass.

Belt the belt 7 comprises at least two cross plies 7A and 7B, in this example, four layers 7A-7D, including two cross-layer 7A and 7B. Each of the layers of belt the belt is made of rubberized cords of high modulus of elasticity, such as steel cords or the like, arranged parallel to each other at angle from 15 to 45 degrees relative to the equator With tires.

The widest layer defining the width of the belt of the belt 7 in this example is the second �Laem 7, as for the radially inner first layer 7A.

In accordance with the present invention, the protector 2 is equipped with four or five longitudinal grooves 8 extending in the longitudinal direction of the tire.

In the embodiment shown in the drawings, the protector 2 is provided with four longitudinal grooves 8, which include: a pair of shoulder longitudinal grooves 8s, located on each side of the equator With tires closer to the edge of The tread, and a pair of longitudinal grooves 8C crown, located on each side of the equator With tires and between the shoulder longitudinal grooves 8s. Thus, the protector 2 is divided in the axial direction of five ribs (circular regions), which include: two ribs 14 of the shoulder regions, each of which is limited to one of The edges of the tread and one adjacent to it by a longitudinal groove 8; and three ribs 11 the crown area between two ribs 14 of the shoulder areas.

In the case of the protector 2, is provided with five longitudinal grooves 8, in addition to the above the shoulder longitudinal grooves 8s and longitudinal grooves 8C crown protector is further provided with a longitudinal groove of the crown 8C located on the tire equator C. Therefore, the protector 2 is divided in the axial direction on six ribs that include the above two ribs 14 of the shoulder areas and four edges 11 of the crown area, located� between them.

In each case, the tread pattern is bi-directional tread pattern, in other words, having point symmetry with respect to any point on the equator of the tire.

The above three or four ribs 11 the crown area include: a couple of ribs 11o axially outer region of the corona, each of which is limited to the adjacent shoulder longitudinal groove 8s and the longitudinal groove 8C of the crown, and one or two ribs 11i axially inner region between adjacent longitudinal grooves 8 with the crown.

Every edge region 11 of the crown is provided with transverse grooves 15 of the crown, spaced from each other in the longitudinal direction of the tire.

Each edge 14 of the shoulder region is provided with shoulder lateral grooves 18 which are spaced from each other in the longitudinal direction of the tire.

Shoulder transverse grooves 18 are arranged with a pitch P in the longitudinal direction, the same as the pitch of the transverse grooves 15 of the crown in the longitudinal direction.

As shown in Fig.2, the longitudinal grooves 8 of the transverse groove 15 of the crown and the shoulder lateral grooves 18 are very small.

Transverse grooves 15 of the crown pass through the entire width of the edges of the area 11 of the crown, therefore, the edge region 11 of the crown is divided in the longitudinal direction of the row of blocks 11 V. however, since transverse�e groove 15 of the crown is very small, as noted above, the blocks 11 In the crown, in essence, not separated from each other by transverse grooves 15 of the crown and as a result, the edge region 11 of the crown maintains the continuity in the longitudinal direction of the tire.

Shoulder transverse grooves 18 of the crown extend from the axially inner edge 14i rib shoulder area 14 to the axially outer edge or the edge of The tread and end, not reaching the edge of The tread. Accordingly, the ribs 14 of the shoulder region is continuous in the longitudinal direction of the tire in appearance. Moreover, due to small shoulder lateral grooves 18 even in the field, provided with shoulder lateral grooves 18 and ribs 14 shoulder area preserve continuity in the longitudinal direction of the tire. Thus, the ribs 14 of the shoulder region is essentially seen as an almost continuous rib.

To regulate or reduce the rigidity of the ribs 11 of the crown area, the preferred use of the slats S to change the depth of the transverse grooves 15. In this case, the slats S are the slits or fine grooves of a width not exceeding 1.5 mm.

Preferably the slats S is provided within the transverse grooves 15 of the crown so that one slat S is formed at the bottom of each groove 15U 15 and extends along the width of the Central line of the groove 15.

The above-mentioned longitudinal grooves 8 are p� essentially rectilinear grooves.

Preferably, the longitudinal grooves 8 are located symmetrically with respect to the tire equator C.

For example, the Central line width 10G of each of the shoulder longitudinal grooves 8s is located on the axial distance L2 of 19 to 23% of the width TW of the tread, axially inward from the edge of The tread.

With the exception of longitudinal grooves 8d of the crown, located on the equator of the tire, the Central line width 9G each longitudinal groove 8C of the crown is located at an axial distance L1 of 8 to 12% of the width TW of the tread from the equator With tires.

Rib shoulder area 14 have an axial width Ws, and the edge region 11 of the crown have an axial width Wc (Wc1, Wc2).

Axial width Ws is not less than 1.3, preferably not less than 1.35 V, but not more than 1.6, preferably not more than 1.5 times the value Wcmin, which is one of the values of the axial width Wc that is not greater than any other value of width Wc.

Attitude Wc2/Wc1 axial width Wc2 ribs 11o axially outer region of the corona to the axial width Wc1 rib 11i axially inner regions of the crown ranges from 0.95 to 1.05 in order to equalize the distribution of soil pressure between the edges of the area of the crown.

In the embodiment shown in the drawings, the axial width Wc1 of the edge region 11 of the crown, located on the equator of the tire, is less than the axial width�on Wc2 ribs 11 of the crown area of each side of this edge.

Thus, between the ribs 11 and 14 improve the distribution of stiffness, thereby improving wear resistance, the stability of the rectilinear motion and characteristics of the movement on the curve.

Each longitudinal groove 8 has a depth D1 from 15 to 20 mm.

In addition, each longitudinal groove 8 has a width W1 of at least 10 mm, preferably not less than 12 mm but not more than 18 mm, preferably not more than 16 mm in order to improve the drainage and the rigidity of the ribs 11 and 14 well-balanced manner.

The depth D2 of the transverse grooves 15 of the crown is not less than 9%, preferably not less than 10% but not more than 30%, preferably not more than 25%, more preferably not more than 20% of the depth D1 of the adjacent longitudinal grooves 8.

The width W2 of the transverse grooves 15 of the crown is not less than 2.5 mm, preferably at least 3.0 mm but not more than 6.0 mm, preferably not more than 5.5 mm to achieve good drainage and stiffness of the ribs 11 of the crown region of the well-balanced way.

Preferably, width W2 is constant along the entire length of the transverse grooves 15 of the crown.

The depth D3 of the shoulder lateral grooves 18 is not less than 9%, preferably not less than 10% but not more than 25%, preferably not more than 22%, more preferably not more than 20% of the depth D1 of the adjacent longitudinal grooves 8.

The width W3 of the shoulder lateral grooves 18 is not less than 2.5 m�, preferably at least 3.0 mm but not more than 6.0 mm, preferably not more than 5.5 mm. width Preferably equal to the width W3 and W2 is constant along the entire length of the shoulder lateral grooves 18.

The axial length L4 of the shoulder lateral grooves 18 which, as shown in Fig.4, measure the width of the Central line of the groove from an axially inner end 18i to the axially outer end of 18O is not less than 78%, preferably not less than 80% but not more than 88%, preferably not more than 86% of the axial width Ws of the rib 14 shoulder area.

Thus, through the above-described arrangement and structure of the grooves 8, 15 and 18, the rigidity of the ribs 11 in the area of the crown is reduced in comparison with the rigidity of the rib 14 in the shoulder region.

As a result of such distribution of stiffness in the tread 2, the energy of friction applied to the protector 2 is aligned between the edge 14 of the shoulder region and the edge region 11 of the crown and therefore may regulate the occurrence of shoulder wear, namely, partial wear, in which the rib 14 shoulder area wears out faster than other areas.

If the depth D1 of the longitudinal grooves 8 is more than 20 mm, the transverse strength (rigidity) of the ribs 11 and 14 is reduced and the wear resistance and the driving stability can deteriorate. If the depth D1 is less than 15 mm, since the volume of the groove of snige�Xia, it becomes difficult to provide the necessary drainage.

If the number of the longitudinal grooves 8 is less than four, it becomes difficult to provide a satisfactory riding characteristics of the tire on a wet road surface. If the number of the longitudinal grooves 8 more than five, since the rigidity of the fin is reduced, it becomes difficult to improve the resistance to tread wear, particularly wear resistance of the shoulder region.

If the depth D2 of the transverse grooves 15 of the crown is more than 30% of the depth D1 of the longitudinal grooves 8, then the rigidity of the rib 11 in the area of the crown is reduced and the wear resistance decreases. If the depth D2 of the groove is less than 9% of the depth 01 the grooves, then it becomes difficult to improve running performance on wet road surfaces.

If the axial width Ws of the rib 14 of the shoulder region is less than 1.3 the values Wcmin, then it becomes difficult to prevent the friction of the ribs 14 shoulder area with the ground, therefore, can occur shoulder wear. If the axial width Ws is more than 1.6 values Wcmin, in the Central area of the tread rubber of the tread could peel off at the edges of the transverse grooves 15 of the crown.

If the depth D3 of the shoulder lateral grooves 18 is more than 25% of the depth D1 of the longitudinal grooves 8, then the rigidity of the ribs 14 in the shoulder region is reduced and the wear resistance decreases. If� depth D3 of the groove is less than 9% of the depth D1, then it becomes difficult to improve running performance on wet road surfaces.

If the axial length L4 of the shoulder lateral grooves 18 is more than 88% of the axial width Ws of the rib 14 of the shoulder region, then the rigidity of the rib 14 of the shoulder region is greatly reduced and it becomes difficult to adjust the shoulder wear. If the axial length L4 is less than 78% of the axial width Ws, you may experience uneven wear along the shoulder longitudinal grooves 8s. Moreover, it becomes difficult to improve running performance on wet road surfaces.

Each rib shoulder area 14, as shown in Fig.4, the shoulder lateral grooves 18 are curved essentially in the middle position 20A in the axial width Ws of the rib 14 of the shoulder area and the shoulder lateral grooves 18 are formed in the same configuration.

Thus, the shoulder lateral groove 18 comprises an axially inner portion 20 extending from an axially inner edge 14i rib shoulder area 14 in the direction of The edge protector angle α4, and an axially outer part 21 extending from an axially inner portion 20 in the direction of The edge protector angle α5, where the angle α4 is at least 10 degrees, preferably not less than 12 degrees, but not more than 35 degrees, preferably not more than 33 degrees relative to the axial voltage�of Alenia tires, and the angle α5 is from -10 to 10 degrees (from 0 to 10 degrees, if not to take into account the direction of the slope), preferably not more than 9 degrees relative to the axial direction of the tire.

Since the edges of the shoulder lateral grooves 18 are inclined relative to the axial direction of the tire, the characteristics of grip in the corner and driving stability can be improved.

If the angle α4 axially inner portion 20 is 35 degrees, then the angle α3 corner of section 14a between the axially inner part 20 and the shoulder longitudinal groove 8s becomes very small and the corner section 14a can be prone to separation. If the angle α4 is less than 10 degrees, then the driving stability during movement on the turn will not be improved.

The distance L3 in the longitudinal direction between an axially inner end 18i and an axially outer end 18O of the shoulder lateral grooves 18, as measured by the width of the Central line 18C of the groove is preferably not less than 10%, more preferably at least 15% but not more than 30%, more preferably not more than 25% of the longitudinal pitch P between adjacent in the longitudinal direction of the shoulder lateral grooves 18. If the distance L3 in the longitudinal direction is more than 30% of the longitudinal pitch P, the rigidity of the rib 14 of the shoulder region can not be e�effectively reduced and can occur shoulder wear. If the distance L3 in the longitudinal direction is less than 10% of the longitudinal pitch P, then the characteristics of grip in the corner and driving stability can not be improved.

As shown in Fig.2, on each side of the equator axial distance from the axially outer end 18O of the shoulder lateral grooves 18 to the equator With tires preferably is at least 95%, more preferably not less than 97% but not more than 105%, more preferably not more than 103% of the axial distance BW axially outer edge belt 7E of the belt 7 from the equator With tires.

Using this arrangement, the entire width of the recessed portion of the tread is provided with shoulder lateral grooves and transverse grooves of the crown, reinforce, thus, uneven wear due to the lateral grooves (decrease stiffness) can be prevented.

The axial distance BW is not less than 0.85, preferably not less than 0,86, but not more than 0.95, preferably not more than 0.94 in half (TW/2) of the width TW of the tread.

If the axial distance BW is less than 0.85 TW/2, it is impossible to reinforce the tread across the whole width, thus, the likely occurrence of uneven wear. If the axial distance BW is more than 0.95 TW/2, the durability of the sidewall of the tread can be reduced. Moreover, the mass of the tire adversely ascending�ceases.

The depth of the aforementioned slats set S so that it is smaller than the depth D1 of the adjacent longitudinal grooves 8, preferably less than 80% of the depth D1. The slats S are the full width of the ribs and both of them end open.

To optimize the distribution of stiffness in the ribs, which are secured slats S, the depth of the sipes S are reducing their both ends So that the ratio Ds1/Ds2 depth Ds1 open on the ends So to the depth of Ds2 in the Central area of Si is 0.5 to 0.8.

In comparison with the width SW of the tire tread width TW of the tread set so that it was slightly wider than usual. Namely, the ratio TW/SW width TW of the tread to the width SW of the tire profile is of 0.78 to 0.87. As a result of the transverse rigidity of the tire is increased to improve the stability of driving. Moreover, the friction ribs shoulder area with the ground and reduce the shoulder wear can be reduced.

If the ratio TW/SW is less than 0.78 is the area of contact with the ground becomes narrow and the resistance to wear of the tread 2 can be reduced. If the ratio TW/SW is more of 0.87, sides, particularly in the area of the location of the maximum section width of a tyre to the edges of the tread are relatively flat and as a result driving comfort may suffer.

As described above, the transverse grooves 15 of the crown and the shoulder lateral grooves 18 are very Melk�e, therefore, to effectively drain water away from the longitudinal grooves 8 in the transverse grooves 15 and 18, the transverse grooves 15 and 18 are radially inward from its axial ends to the bottom of the longitudinal grooves 8 along the side walls of the longitudinal grooves 8 so that each side wall has a radially recesses (V), alternating with substantially flat surfaces (F) of the side walls.

Radially recesses (b) In this example, gradually increases in width (measured in the longitudinal direction of the tire) from the bottom (the deepest portion in the axial direction of the tire) to the exit (the side walls). Thus, this part (b) has a substantially trapezoidal cross section. The depth of recesses radially (In) is limited in the same range as in the transverse groove.

In this embodiment as the transverse grooves 15 are two types of zigzag grooves, zigzag grooves 16 oblique and zigzag grooves 17 of the parallel type.

Zigzag grooves 16 are inclined in a broken line along the inclined line inclined at an angle relative to the axial direction of the tire in one of longitudinal directions.

Zigzag grooves 17 of the parallel type are in the form of a broken line along a straight line, essentially pairs�lelei axial direction of the tire.

More specifically, zigzag grooves 16 of the inclined type consist of three linear parts, which represent the first inclined portion 16A, the second inclined portion 16 b and a third inclined portion 16C which are inclined relative to the axial direction of the tire in one of longitudinal directions (in the drawing, the tilt to the right).

The first inclined portion 16A extends from one axial end to another axial edge of the edge region 11 of the crown, at an inclination angle α1 relative to the axial direction of the tire.

The second inclined portion 16B extends from the first inclined portion 16A to the other axial edge of the edge region 11 of the crown, at an inclination relative to the axial direction of the tire angle α2 is greater than the angle α1.

The third inclined portion 16C extends from the second inclined portion 16B to the other axial edge of the edge region 11 of the crown at an inclination relative to the axial direction of the tire, at an angle α3, smaller than the angle α2.

The angle α1 is between 15 to 25 degrees.

The angle α2 is between 40 to 50 degrees.

The angle α3 is 15 to 25 degrees.

Preferably, the angle α1 is equal to the angle α3.

Zigzag grooves 17 of the parallel type are composed of three linear parts, which represent the first inclined portion 17A, the second inclined portion 17B and the third inclined portion 17C.

The first inclined� portion 17A extends from one axial end to another axial edge of the edge region 11 of the crown at an inclination to one of the longitudinal directions at an angle α6 relative to the axial direction of the tire.

The second sloping portion 17 extends from the first inclined portion 17A to the other axial edge of the edge region 11 of the crown when tilted in the other longitudinal direction opposite to the direction of inclination of the first inclined portion 17A, the angle α7 cameras relative to the axial direction of the tire.

The third inclined portion 17C extends from the second inclined portion 17B to the other axial edge of the edge region 11 of the crown at an inclination to the longitudinal direction opposite to the direction of inclination of the second inclined portion 17B, the angle α8 relative to the axial direction of the tire.

The angle α6 is 15 to 25 degrees.

The angle α7 cameras ranges from -15 to -25 degrees.

The angle α8 is 15 to 20 degrees.

In this example, the angles α6, α7 cameras and α8 of the same size.

In the case where the protector is provided with four longitudinal grooves 8, as shown in the drawings, preferably the transverse groove 15 of the crown, secured in the ribs 11o axially outer region of the corona, are zigzag grooves 17 of the parallel type, and the transverse grooves 15 of the crown, secured on the rib 11i axially inner regions of the crown, located on the equator With tires represent zigzag grooves 16 of the inclined type.

In the case where the protector is provided with five longitudinal grooves 8, the transverse groove 15 of the crown, provided�built on the edges 11o axially outer region of the corona, are zigzag grooves 17 of the parallel type, and the transverse grooves 15 of the crown, secured at the edges 11i axially inner regions of the crown, located on each side of the equator With tires that can represent zigzag grooves 16 of the inclined type or, alternatively, zigzag grooves 17 of the parallel type.

In any case, preferably, the transverse grooves (15, 18) to each edge (11, 14) substantially parallel to each other.

Moreover, to facilitate the drainage from the Central zone of the tread to the edges of the tread, it is preferable that an imaginary continuation of each of the transverse grooves (15, 18) coincides with an imaginary sequel to one of the neighboring in the axial direction of the transverse grooves (15, 18).

More specifically, in the case of the example shown in Fig.3, the axially inner continuation of the Central line width 15C each zigzag grooves 17 of the parallel type (transverse grooves 15) coincide with the axially outer continuation of the Central width of the line 16C of one of the zigzag grooves 16 parallel type (transverse grooves 15) and axially outer continuation of the Central line width 17C above zigzag grooves 17 of the parallel type (transverse groove 15) coincide with the axially inner continuation of the TSE�sweeping across the width of the line 18C of one of the shoulder lateral grooves 18.

Thanks to the zigzag configuration of the grooves 16 and 17, the total length of the edges of the grooves increases and the characteristics of the grip can be improved.

Because zigzag grooves 16 oblique tilted in one direction of rotation of the tire, the water between the tread surface and the road surface is discharged in the direction of the grooves 16 and characteristics of the drainage improved. If the angles α1, α2 and α3 are outside the above ranges, it becomes difficult to improve the characteristics of the drainage.

Since the angle α1 is equal to the angle α3 and the angle equal to the angle α6 α8, the rigidity of the edge region of the crown is aligned between both edges in the axial direction of the tire and the occurrence of uneven wear is effectively govern.

Zigzag grooves 16 and 17 provided with slats S along their Central line width, namely, a zigzag center line, as described above, therefore, the opposite wall of the edge elements separated by slats can be coupled with each other, if subjected to lateral force. As a result, the rib acts as a continuous rib against the attached shear force and the deterioration of the driving stability can be prevented.

To small objects such as stones on the roads, not trapped inside the longitudinal grooves 8, preferably n� least longitudinal grooves 8 of the crown is provided at the bottom 9U grooves of independent protrusions N. The tabs H are spaced from each other along the width of the Central line of the groove, and in this example, the ledge N has an almost rectangular configuration, as shown in Fig.1 and 2.

Comparative tests

In accordance with the internal structure shown in Fig.1, and a tread pattern shown in Fig.3, made of heavy-duty tires of size 295/80R22.5 (rim size: 22,5×9,00) for trucks and buses and were tested for resistance to shoulder wear and handling characteristics on wet road surfaces.

All tires had the same structure except for the characteristics presented in table 1.

Test running performance on wet road surfaces

The test vehicle (a truck with a wheel type 2DD) installed on the front wheels of the test tires (tire pressure 850 kPa) was tested on a circle of radius 60 meters on a wet asphalt road covered with water to a depth of 1-2 mm, and measured the fastest time of the passage of five circles. Vertical load of the tire was 50% on the load bar mounted ETRTO. The reciprocal of the measured time, in seconds, are presented in table 1 by the value based on the value for comparative example CP.1 taken as 100, wherein the larger the magnitude of t�, the better.

Test of resistance to shoulder wear: after the above tests, the vehicle is tested at a distance of 20,000 km, measured the difference between the radius of the tire between the edges 14 of the shoulder region and the edge 11o axially outer region of the corona, to assess the extent of the shoulder wear.

The results are presented in table 1, where the smaller the value, the higher the resistance to shoulder wear.

From the test results it is obvious that as resistance to shoulder wear and handling characteristics on wet road surface can be improved.

Table 1
BusCP.1CP.2CP.3CP.4CP.5CP.6CP.7CP.8CP.9CP.10
Figure
the projector (Fig.)
633333333 3
D2/D1 (%)-7915253032202020
D3/D1 (%)off7777777913
L4/WS (%)-767676767676767676
A/BW (%)-929292929292929292
L3/P (%)-161616161616161616
BW/(TW/2) (%)100100100100100100100100100100
Shoulder wear (mm)0,50,70,70,80,81,11,2080,70,9
Characteristics on wet roads100102104106108110107105105 106
BusCP.
11
Wed, 12CP. 13D. 1D. 2D. 3CP. 14D. 4D. 5D. 6
Figure
the projector (Fig.)
3333333333
D2/D1 (%)202020202020202020D3/D1 (%)25271717171717171717
L4/WS (%)76767678838890838883
A/BW (%)92929293949698100105100
L3/P (%)16161616161616161630
BW/(TW/2) (%)100100100100100100100949194
Shoulder wear (mm)1,11,20,90,70,70,81,30,60,90,7
Characteristics on wet roads110110107109109110110109110110

General features:

Tread width TW: 239 mm=80% of the width SW of the tire profile

Longitudinal grooves

width W1:14.0 mm

the depth D1:16.5 mm

Longitudinal grooves of the crown

the axial distance L1 from the tire equator: 9% of the width TW

protector

The shoulder longitudinal grooves

axial distance�their L2 from the equator of the tire: 20% of the width TW

protector

Shoulder transverse grooves

width W3:4.0 mm

the angle α4:16 degrees

the angle α5:0 degree

longitudinal step D: 36 mm

Transverse grooves of the crown

width W2:4.0 mm

the depth D2: 12% of the depth D1

Zigzag grooves 16 of the inclined type

the angle α1: 19 degrees

the angle α2: 44 degrees

the angle α3: 19 degrees

Zigzag grooves 17 parallel type

the angle α6: 19 degrees

the angle α7 cameras: 20 degrees

the angle α8: 19 degrees

List of designations

2 - the Protector

3 - Side panel

4 - Board

5 - bead ring

6 - Frame

7 - Belt belt

8 (8s, 8c) has a Longitudinal groove (humerus, crown)

11 (11i, 11o) - Edge region of the corona (internal, external)

14 - Edge of shoulder region

15 is a Transverse groove of the crown

16 - Zigzag groove inclined type

17 - Zigzag groove parallel type

18 - Shoulder lateral groove

SW - Width tyres

The Edge protector

TW - tread Width

1. Heavy bus, including:
protector with the edges of the tread defining the width TW of the tread,
a pair of sidewalls defining the width SW of the cross-section of the tire,
a pair of sides, each side with a ring inside, a carcass extending between the sides through the tread and sidewall and belt belt consisting of a belt layer of the belt located �Adelino outside of the carcass in the tread, where
the width TW of the tread is of 0.78 to 0.87 width SW of the cross-section of the tire,
the protector is equipped with four or five longitudinal grooves, each of which has a depth of from 15 to 20 mm and runs continuously in the longitudinal direction of the tire so that in the axial direction divides the tread into five or six ribs, these five or six ribs include a pair of ribs shoulder area, passing along the edges of the tread and provided with shoulder lateral grooves, and three or four ribs the crown area, located between the shoulder ribs and provided with transverse grooves of the crown,
these transverse grooves of the crown are spaced from each other in the longitudinal direction of the tire and passes through the entire width of the edge region of the corona, and the depth of the transverse grooves of the crown ranges from 9 to 30% of the depth of the longitudinal grooves,
these shoulder transverse grooves spaced from each other in the longitudinal direction of the tire and passing axially outward from the axially inner edge of the shoulder rib area so that end at an axial distance from 78 to 88% of the axial width of the shoulder rib area from the specified axial inner edge, and the depth of the shoulder lateral grooves is from 9 to 25% of the depth of the longitudinal grooves.

2. Heavy-load tire according to claim 1, in which the axial races�the ground state (A), measured from the equator of the tire to an axially outer end of the shoulder longitudinal grooves ranges from 95 to 105% of the axial distance BW, measured from the equator of the tire to an axially outer edge belt belt.

3. Heavy-load tire according to claim 1, in which the shoulder lateral groove is curved and comprises an axially inner portion extending from the axially inner edge of the shoulder rib area to the edge of the tread at an angle between 10 degrees to 35 degrees relative to the axial direction of the tire, and an axially outer portion extending from the axially inside to the edge of the tread at an angle of -10 degrees to 10 degrees relative to the axial direction of the tire.

4. Heavy-load tire according to claim 1, in which when measured along the Central line of the groove, the longitudinal distance between the axially inner end and an axially outer end of the shoulder lateral grooves is from 10 to 30% of the stride length in the longitudinal direction between adjacent in the longitudinal direction of the transverse grooves.

5. Heavy-load tire according to claim 1, in which the axial width of the shoulder rib area is from 1.3 to 1.6 axial width of one of the edges of the area of the crown, which is not wider than any other edge region of the corona.

6. Heavy-load tire according to any one of claims.1-5, in which at the bottom of each transverse grooves of the crown provided l�stranded, passing along the length of the transverse grooves of the crown.



 

Same patents:

High-capacity tire // 2550631

FIELD: transport.

SUBSTANCE: invention relates to automotive industry. High-capacity tire includes tread provided with central longitudinal groove, crown longitudinal grooves at each side of this groove and crown lateral grooves passing between them thus crating blocks of crown. Crown block is additionally divided in longitudinal direction into two parts of the block by narrow groove of crown. Lateral groove of crown is provided at its bottom with web extending from bottom and connecting two crown blocks being adjacent in longitudinal direction. Lateral grooves of crown are inclined at an angle α of 10 to 30 degrees relative to axial direction of tire. The central longitudinal groove and axially-inner part of lateral crown groove which is located at axially inner side of web are of least depth than longitudinal groove of crown.

EFFECT: better tread self-cleaning of stones without creation of cracks at the bottom of groove and without performance degradation on wet road surface.

8 cl, 4 dwg, 1 tbl

Pneumatic tire // 2550237

FIELD: transport.

SUBSTANCE: invention relates to automotive winter tire tread design. In the tread part, multiple longitudinal and lateral grooves are made. They determine boundaries of multiple rows of blocks. Each of the blocks includes sipes. Length of each of the blocks included into the first row of blocks and the second row of blocks is at least 1.5 times and not more than 2.5 times greater than length of each of the blocks included into the third row of blocks. Width of each of the blocks included into the second row of blocks is greater than width of each of the blocks included into the first row of blocks. Lateral grooves determining boarders of blocks in the first row of blocks and lateral grooves determining boarders of blocks in the second row of blocks are located with shift relative to each other in direction along tire circumference for a distance of at least 0.2 and at most 0.8 of the length of each of the blocks in the first row of blocks. Lateral grooves determining boarders of blocks in the second row of blocks and lateral grooves determining boarders of blocks in the third row of blocks are located so that they communicate with each other being inclined in the same direction relative to tire width direction.

EFFECT: improved operational performance during movement over ice and snow with good balance.

11 cl, 8 dwg, 1 tbl

High-capacity tire // 2541553

FIELD: transport.

SUBSTANCE: invention relates to automotive industry, particularly, to high-capacity tires. Tire comprises tread with blocs each being provided with zigzag-like blade made at the surface of contact with soil. Relationship between bloc length A measured in straight line crossing the centre of gravity of said contact surface and bloc maximum width (B) making the axial spacing between the most remote edges of said contact surface varies from 0.8 to 1.7. Said zigzag blade is located at central area extending from the centre of gravity of said contact surface on both sides of lengthwise direction through 25% of block length (A). Said zigzag-blade consists of two straight larger length sections extending axially inward from both sides of the blocs in the tire axial direction. Besides, it includes straight section of smaller length extending between inner ends of said larger-length sections so that lengthwise spacing between said most remote ends of said blade varies from 10 to 35% of bloc length (A).

EFFECT: reduced stepwise wear at sufficient road grip.

8 cl, 6 dwg

Pneumatic tire // 2537987

FIELD: transport.

SUBSTANCE: invention relates to motor tire tread pattern. Tire tread is provided with blocks each one of which has surface of block wall facing transversal groove tilted at an angle (Θ) of 5 to 40 degrees relative to axial tire direction and thus forming acute-angled edge and obtuse-angled edge of block. Block wall surface between acute-angled edge and obtuse-angled edge is provided with at least two slots of 0.3 to 2.0 mm in width. Distance P2 measured from acute-angled edge to one of at least two mentioned slots the nearest to acute-angled edge is greater than distance P1 measured from mentioned obtuse-angled edge to one of at least two mentioned slots the nearest to obtuse-angled edge. Each distance is measured along radially outer edge of block wall surface to slot centre across width.

EFFECT: tire noise reduction.

10 cl, 5 dwg, 1 tbl

Winter tire // 2531435

FIELD: transport.

SUBSTANCE: invention relates to winter tire. Tire (1) comprises multiple blocks (6a, 6b), at least one slit-like retaining-type drain groove (6a, 6b) extending in at least one block of said set in, in fact, axial direction (X) defined at said tread band. Said first slit-like retaining-type drain groove is configured to make between the first (8) and the second (9) parts of the block at least two separate joints (11) of "recess-ledge" type separated by said first groove to rule out the relative shifts of said blocks in whatever direction (A).

EFFECT: better grip on wet, snowy or icy roads.

16 cl, 2 dwg, 1 tbl

FIELD: transport.

SUBSTANCE: invention relates to tread of tires to be used in winter. Winter tire (1) has tread (2) with relied patter composed of multiple lengthwise grooves (4) and crosswise grooves (5) isolating the blocks (6) extending radially from base surface (3) of tread (2) to make at least one lengthwise row. Every block (6) has two lengthwise lateral surfaces (7) that make the boundaries of two appropriate lengthwise grooves (4) and two crosswise side surfaces (8) that make the boundaries of two appropriate crosswise grooves (5). At least one of units (6) has lateral channels (9) each being formed at side surface (7, 8) of appropriate block (6) to extend from base surface (3) of tread (2) to top surface (10) of block (6) to prevent radial extension of trapped snow from inner section of lateral channel (9).

EFFECT: perfected grip and snow-clad roads.

19 cl, 16 dwg

FIELD: transport.

SUBSTANCE: invention relates to pneumatic tire for vehicles, in particular to be used in winter conditions of driving. Tread is provided with multiple narrow sipes (4) which pass in transversal direction of tread in parallel to each other. Mutually opposite walls (5) of sipes contain mutually matching projections (6, 7) and recesses (16, 17). The projections (6, 7) are rounded raised areas. The projections (6) are located in separate areas in radially outer region of one sipe wall (5). In this structure, each of mentioned projections (6) has one flat side forming supporting surface (6a) oriented in radial direction and essentially perpendicular to sipe wall (5). The projections (7) are located in separate areas in radially inner region of one sipe wall (5). In this structure, each of mentioned projections (7) has one flat side forming supporting surface (7a) passing essentially in parallel to upper surface of positive profile.

EFFECT: better tire adhesion to ice-covered road surface while providing uniform wear of tire tread.

10 cl, 3 dwg

Pneumatic tire // 2526573

FIELD: transport.

SUBSTANCE: invention relates to tread pattern of automobile tire intended to be used on ice. On the surface of tire crown zone located between both edges of tread there are multiple grooves positioned in circumferential direction of tire; multiple transversal grooves located in transversal direction of tire. Each of transversal grooves has point of curvature between main grooves and/or between main groove and tire edge so that they have convex from in circumferential direction of tire. Multiple main grooves and multiple transversal grooves from multiple separate blocks each one of which includes circumferential projection of shape that coincides with convex form of transversal grooves. Each of the blocks contains at least one transversal lamel located in tire transversal direction and coinciding in its shape with transversal grooves where transversal lamel size in tire transversal direction is equal to size of block with transversal lamel located in it if both ones are projected on one plane including tire rotation axis and perpendicular to block surface.

EFFECT: better tire friction properties on ice.

10 cl, 6 tbl, 14 dwg

Pneumatic tire // 2523539

FIELD: transport.

SUBSTANCE: pneumatic tire 1 having excellent snow-running characteristics while keeping control stability and resistance to uneven wear, including tread 2 containing a pair of longitudinal crown grooves running continuously in longitudinal direction of tire at both sides of tire equator C and having edges, where one edge 3m runs in zigzag fashion, so that L-shaped sections 3s of groove edge are continuously interconnected in tire longitudinal direction, and the other edge 3n runs in corrugated manner so that arc-shaped sections of groove edge 3o having arc-shaped convexity towards groove centre are continuously interconnected in tire longitudinal direction where each section 3s of L-shaped groove edge includes long portion 3c inclined at angle of 1 to 20° relative to longitudinal direction, and short portion 3t with longitudinal length less than this value for long portion 3c and inclined in direction opposite to direction of the mentioned long portion 3c relative to longitudinal direction.

EFFECT: improved characteristics.

17 cl, 1 tbl, 10 dwg

FIELD: transport.

SUBSTANCE: tire tread has at least two wearing plies including outer wearing ply and at least one inner wearing ply located at mid tread under outer wearing ply, and at least one outer groove located in outer wearing ply. Besides, said tread features volumetric cavity ratio of 0.25-0.40 in sound state and of about 0.25-0.40 in worn-out state. External side interacting with ground extends along one of inner wearing ply in worn-out tread. Additionally, said tread features contact surface ratio of 0.66-0.72 in sound state and of about 0.56-0.66 in worn-out state.

EFFECT: enhanced performances.

15 cl, 19 dwg

Pneumatic tire // 2550237

FIELD: transport.

SUBSTANCE: invention relates to automotive winter tire tread design. In the tread part, multiple longitudinal and lateral grooves are made. They determine boundaries of multiple rows of blocks. Each of the blocks includes sipes. Length of each of the blocks included into the first row of blocks and the second row of blocks is at least 1.5 times and not more than 2.5 times greater than length of each of the blocks included into the third row of blocks. Width of each of the blocks included into the second row of blocks is greater than width of each of the blocks included into the first row of blocks. Lateral grooves determining boarders of blocks in the first row of blocks and lateral grooves determining boarders of blocks in the second row of blocks are located with shift relative to each other in direction along tire circumference for a distance of at least 0.2 and at most 0.8 of the length of each of the blocks in the first row of blocks. Lateral grooves determining boarders of blocks in the second row of blocks and lateral grooves determining boarders of blocks in the third row of blocks are located so that they communicate with each other being inclined in the same direction relative to tire width direction.

EFFECT: improved operational performance during movement over ice and snow with good balance.

11 cl, 8 dwg, 1 tbl

FIELD: transport.

SUBSTANCE: proposed tire comprises directed patter defining the direction of tire rotation and at least one crosswise groove on tread surface extending from tread edge and inward in direction over tread width beyond central point P of tread width half. Here this tread edge is located whereat groove wall of expulsion side has of at least one crosswise groove has the ledge. The latter extends towards inlet side groove wall relative to point Q. The latter represents the mid distance, over tread width, from tread edge to point P of tread width half. Note here that said ledge extends from position between points P and Q and inward beyond point Q in direction over the tread width.

EFFECT: higher resistance to abrasive wear.

4 cl, 6 dwg, 1 tbl

Pneumatic tire // 2548308

FIELD: transport.

SUBSTANCE: invention relates to tire tread. Pneumatic tire (10) tread (12) comprises two peripheral main grooves (14) made nearby the tire width centre some 1/3 of width W of the surface of contact with soil from edge (7) of said surface and oriented towards tire circumference. Central tread (16) arranged between two peripheral main grooves (14). Side grooves (18) are made on sides over tore width outside both peripheral main grooves (14). Main crosswise grooves (20) are arranged in side treads (18) extending from peripheral main grooves (14) to edges T of the surface of contact with soil. Side treads (18) include no main grooves to connect adjacent main crosswise grooves (20) with each other.

EFFECT: higher adhesion, better stability of control and acceleration characteristics on ice.

3 cl, 2 dwg, 2 tbl

FIELD: transport.

SUBSTANCE: invention relates to the automotive industry. A tyre frame being a tyre base, and a vulcanised tread which is glued to the tyre frame, are formed separately and connected to each other, forming the tyre. The tread, in its cross (axial) direction, has a set of grooves passing in its longitudinal (circumferential) direction. The tread thickness in the cross section gradually decreases from the equator to the edge from the side of the equator of the extreme external groove located in axial and extreme external area and is gradually increased from the external edge of the extreme external groove outside in the axial direction.

EFFECT: possibility of the regulation of uneven wear of the tread.

6 cl, 7 dwg

Pneumatic tire // 2523539

FIELD: transport.

SUBSTANCE: pneumatic tire 1 having excellent snow-running characteristics while keeping control stability and resistance to uneven wear, including tread 2 containing a pair of longitudinal crown grooves running continuously in longitudinal direction of tire at both sides of tire equator C and having edges, where one edge 3m runs in zigzag fashion, so that L-shaped sections 3s of groove edge are continuously interconnected in tire longitudinal direction, and the other edge 3n runs in corrugated manner so that arc-shaped sections of groove edge 3o having arc-shaped convexity towards groove centre are continuously interconnected in tire longitudinal direction where each section 3s of L-shaped groove edge includes long portion 3c inclined at angle of 1 to 20° relative to longitudinal direction, and short portion 3t with longitudinal length less than this value for long portion 3c and inclined in direction opposite to direction of the mentioned long portion 3c relative to longitudinal direction.

EFFECT: improved characteristics.

17 cl, 1 tbl, 10 dwg

Automotive tire // 2521033

FIELD: transport.

SUBSTANCE: invention relates to automotive winter tire tread design. Tire (1) has tread (2) containing central part (L1) covering from two sides the equatorial plane (7), and two shoulder parts. The central part (L1) is separated from shoulder parts (L2, L3) of tread by two first circumferential grooves (3, 6). At least two second circumferential grooves (4, 5) are located in the central part (L1). The second circumferential grooves (4, 5) determine margins of the central circumferential bar (10) containing multiple sipes (20) located in parallel to each other and at certain distance from each other. The second circumferential grooves (4, 5) have a mid line running as peak-to-valley scallops throughout tire length in direction along circumference. The mid lines with peak-to-valley scallops are mainly matching in phase with each other throughout tire length (1) in direction along circumference.

EFFECT: better operational properties when moving both over snowy and dry and wet road surfaces.

20 cl, 4 dwg, 1 tbl

Pneumatic tire // 2520265

FIELD: machine building.

SUBSTANCE: proposed tire comprises tread zone (A) located from vehicle inner side and tread zone (B) located on vehicle outer side. There are multiple slot-like drain grooves (32A, 32B) extending over tire width and formed in every block (31A, 31B). The number of blocks (31A) in said zone (A) is larger than that of blocks (31B) in said zone (B). Note here that slot-like drain grooves (32B) in blocks (31B) of zone (B) are configured to extend linearly along their depth. Note here that slot-like drain grooves (32A) in blocks (31A) of zone (A) are configured to extend in wavy manner along their depth.

EFFECT: better road grip on dry road and snow.

7 cl, 4 dwg

FIELD: transport.

SUBSTANCE: invention relates to automotive industry, namely, to tread pattern. Tire features tread asymmetric patter wherein ratio of actual area of contact to total area for zone 2o of outer side is larger than that for inner side zone 2i but with minor difference characteristic of water removal for right and left wheel tires. Said tire has tread surface 2 divided by four lengthwise grooves 3 and 4 into central area 5 of contact with soil, mid areas 6,6 of contact with soil and shoulder areas 7,7 of contact with soil. Said mid area 6o and shoulder area 7o in outer side zone 2o are divided by outer mid transverse grooves 8o and outer shoulder transverse grooves 10o into blocks 9o and blocks 11o. Mid transverse grooves 8o are inclined in opposite direction to inclination of shoulder transverse grooves 10o relative to tire axial direction while transverse grooves 8o and 10o are inclined at angle θmo of 5-45° and at angle θso over 0° and not over 40°, respectively.

EFFECT: better stability in rainy and dry weather.

8 cl, 6 dwg, 1 tbl

FIELD: transport.

SUBSTANCE: tread 2 has rounded shoulders and is divided by the main lengthwise grooves 3 and crosswise grooves 4 in blocks 5 furnished with pockets 6, each having zigzag part 8. Lengthwise grooves 3 include at least two axially outer lengthwise grooves 3o dividing the tread 2 into shoulders Ysh and crowns Ycr wherein zigzag part 8 of pockets 6sh in shoulders Ysh features larger zigzag amplitude Wsh and larger zigzag pitch Psh that zigzag amplitude Wcr and zigzag pitch Wcr of zigzag part 8 of pockets 6cr in crowns Ycr. Inclination angle θsh of pockets 6sh relative to axial direction is smaller than angle θcr.

EFFECT: improved flotation at dry road at minimum deterioration of performances on snow-covered road.

7 cl, 7 dwg, 1 tbl

Pneumatic tire // 2507083

FIELD: transport.

SUBSTANCE: invention relates to tread of tires to be used in winter equipped with antiskid studs. Proposed tire comprises tread with lengthwise blocks. Note here that said blocks comprises drilled blocks, each being provided with not-through hole to fit the stud therein. Said not-through hole is shifted towards the edge of drilled block. Raised not-through reinforcing part is made so that wall thickness (t) makes at least 5 mm for wall around said hole. Said blocks including drilled blocks feature identical geometry apart from said raised reinforcing part.

EFFECT: better run on ice and snow, sufficient life.

12 cl, 7 dwg, 1 tbl

Pneumatic tire // 2550237

FIELD: transport.

SUBSTANCE: invention relates to automotive winter tire tread design. In the tread part, multiple longitudinal and lateral grooves are made. They determine boundaries of multiple rows of blocks. Each of the blocks includes sipes. Length of each of the blocks included into the first row of blocks and the second row of blocks is at least 1.5 times and not more than 2.5 times greater than length of each of the blocks included into the third row of blocks. Width of each of the blocks included into the second row of blocks is greater than width of each of the blocks included into the first row of blocks. Lateral grooves determining boarders of blocks in the first row of blocks and lateral grooves determining boarders of blocks in the second row of blocks are located with shift relative to each other in direction along tire circumference for a distance of at least 0.2 and at most 0.8 of the length of each of the blocks in the first row of blocks. Lateral grooves determining boarders of blocks in the second row of blocks and lateral grooves determining boarders of blocks in the third row of blocks are located so that they communicate with each other being inclined in the same direction relative to tire width direction.

EFFECT: improved operational performance during movement over ice and snow with good balance.

11 cl, 8 dwg, 1 tbl

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