FI109006B - Pneumatic tyre - Google Patents

Description

109006

The present invention relates to a pneumatic tire having an improved tread pattern, which has a better grip on the road without sacrificing wear resistance or tread life.

To prevent dust pollution, heavy vehicles such as trucks and buses on snowy and icy roads have recently become more heavily reliant on studded tires instead of studded tires.

15 Studless tread patterns are widely used for high traction and braking power. To improve traction and braking force, the tread knobs are generally provided with axially extending sipes (20) to divide each piece into relatively narrow tread elements having free axial ends located at a circumferential main groove and / or tread edge. The narrow tread elements thus formed move easily during travel and tend to wear unevenly along their edges. Because the movement is very large at the free ends, the wear at the free ends in particular is very high and the tends to tear off.

.. Such axial sills, on the other hand, cannot improve the resistance to transverse skidding during the arc »> • 'reaction, nor do they prevent the vehicle from expecting a transverse movement on a slippery road during braking' or roll off.

Japanese Patent Publication No. 2-333756 discloses a pneumatic tire having a transverse direction of the vehicle. in order to prevent skidding and hiking during driving well *, ': on paved but shallow 109006 2 roads, the tread is provided, as shown in Figure 10, with at least two circumferentially narrow slats (b) between each shoulder (a) and the tread edge (e), and these pieces (a, b) 5 are divided by circumferentially extending grooves (g) having a width of 2.0 to 4.5 mm.

Because of the small width of the knobs (b) and the relatively large width of the grooves, the frictional stiffness of the tread shoulder is reduced, which effectively prevents hiking. However, since these narrow buttons (b) move easily and this movement is very large due to the high groove width, these narrow button edges cannot effectively adhere to the road surface. In addition, the narrow knobs (b) ku-15 promise fast, which increases uneven wear. The narrow knobs (b) also have a tendency to tear off.

It is therefore an object of the present invention to provide a pneumatic tire which, by using circumferential soaps, and in particular by determining their locations and sizes, e.g., width, depth and the like, improves the transverse slip properties on snow / icy roads. without having to give up * * · 25 resistance to uneven wear, * * * durability of the tread, resistance to detachment.

4 t * (· According to the present invention, the pneumatic tire comprises a tread 30 having two tread edges, wherein said tread is provided with two main t 1-i circumferential grooves disposed at symmetrical * Ί * axial positions relative to the center line of the tire , and with an axial groove i · · * ,,, · for defining at least one circumferential wear surface 35 for each circumferential, *,; main groove, each of the tread surface buttons is provided with at least one sipe 3 in width. 00 09006 0.2 - 1.5 mm, extending continuously substantially parallel to the main groove for dividing the knob into a wider main area and a narrow transverse portion on the circumferential main groove The invention is characterized in that the i 5 narrow transverse portion is more than 3.0 times but less than 20.0 times the groove width of the main circumferential groove so that the average depth of each sipe is 0.25 - 1.0 times and that the depth of the axial grooves is greater than 0.40 but less than 1.0 times the groove depth of the circumferential main groove.

In the following, an embodiment of the present invention will be described in detail with reference to the accompanying drawing, in which: Figure 1 shows a plan view of a pin according to the invention. a tire / bus tire tread section; Figure 2 shows a cross-section of a tire;

Fig. 3 is a perspective view of a shoulder portion of its tread on a larger scale; | Figure 4 shows a plan view of a tread pattern modification; •% * ·

Figures 5-9 graphically depict test results; and Fig. 10 is a perspective view of a shoulder portion of an earlier type 30 tread.

•

In Figures 1-3, the pneumatic tire 1 comprises a tread member 12 having a tread 2 having two edges E, two bead members 14 spaced axially apart 35, two lateral members 13 extending between the tread edges E and the bead members 14 , ball, ·. ; a ring 15 disposed on each ball member 14, a ring-shaped carcass 16 extending between the ball members 14 and folded up around the diaphragm yarns 15, and a belt 19 disposed radially outside the carcass 16 and inside the tread member 12.

5

The frame 16 comprises at least one belt layer or belt structure of the semi-belt type. In this embodiment, the frame cords are disposed radially at an angle of 70 ° to 90 ° with respect to the centerline C of the ring.

10

Steel cord and organic fiber cord, such as nylon, polyester, rayon, aromatic polyamide and the like, can be used for the framework cords.

15

The belt 19 comprises two or more cross layers in which the belt cords are arranged parallel to each other but transversely to the cords I on the next layer. In this embodiment, the belt 19 consists of three cross layers 20.

Steel cord and organic fiber cord, such as nylon, polyester, rayon, aromatic polyamide and the like, can be used for belt cords.

The abovementioned tread section 12 is provided at its tread 2 with wide circumferential main grooves GO which extend uniformly around the ring. In this example • 'l'. 3 0 circumferential main grooves GO with central knee

a flat groove 6 disposed in the center line C of the ring

Ii <; and two axially outermost straight grooves ... G02, one of which is located on either side of the tire centerline, and two straight center grooves GO1, each 35 disposed between grooves 6 and G02, whereby the tread portion is divided into six axial portions. These six axial, · [. the portion is circumferentially divided by axial grooves (g) extending from tread edges E in axial direction to outermost circumferential main grooves G02, and by axial grooves extending between adjacent wide circumferential main grooves GO. Accordingly, the tread pattern of this 5 embodiment is a button pattern consisting of buttons B arranged in six circumferential rows.

The above-mentioned paired grooves G02 and G02 are positioned at symmetrical axial points with respect to the centerline C of the ring, and also the pairwise grooves GO1 and GO1 are disposed at symmetrical axial points.

Each of the axial grooves, including the outermost grooves (g) in the axial direction, forms a bend in its central portion. The axial grooves are disposed such that the grooves in the axial direction of the tire generally extend uniformly from one tread edge E to another tread edge E. Because the thus-formed tread grooves extending across the entire width of the tread are parallel to each other and tilted up). In this embodiment, however, the axial grooves on each of the outermost circumferential grooves G02 in each axial direction are slightly: · · manually displaced in the circumferential direction of the ring, as shown in Figure 1, h1 :.

• »

Accordingly, the outermost circumferential directions are formed.;; ·. 3 0 its groove G02 and its adjacent tread edge E

between the shoulder straps SB line SBA.

... Between each circumferential center groove GO1 and the adjacent outermost circumferential groove G02, a row 5A consisting of center knobs 5 is formed.

. Between circumferential grooves GO1 and GO1 »» 1 · M | »» 109006 In addition, a row 4A consisting of the middle wear surface buttons 4 is formed on each side of the 6 dashed line C.

Since the shoulder blades SB are defined by a straight circumferential groove G02, by the tread edge E and the curved axial grooves (g), each shoulder SB in this embodiment is provided with two straight side edges and two curved front / rear edges.

The circumferential spacing of the axial grooves (g) is such that the circumferential length L of the shoulder blades, measured axially along the inner lateral edge, is 3.0 to 20.0 times the groove width GW of the adjacent circumferential main groove G02.

15

The groove depth gH of the axial grooves is preferably greater than 0.40 times and not greater than 1.0 times the groove depth GH of the main circumferential groove GO.

Each of the shoulder blades SB is axially distributed by means of a narrow circumferential oat groove GB in the axial direction to the outer shoulder section SB1 and axially into the inner shoulder section SB2.

• · * 25 The narrow circumferential shoulder groove GB is a straight groove extending parallel to the tread edge E from the front edge of the shoulder bracket SB to its rear edge, and disposed such that, in the axial direction, the outer shoulder bracket: · .. the component SB1 has an axial width WSB1 of 0.06 to 0.25 times the tread half width TW between the center line C of the tire and one of the tread edges E.

In this embodiment, the width WSB1 is constant in the circumferential direction of the tire but can be varied.

35: **: If the width of WSB1 is less than 0.06 times the wear pin, · '; The half width TW decreases in the axial direction the stiffness of the outer shoulder piece SB1 109006 7, whereby uneven wear is likely to occur. If the width of WSB1 is greater than 0.25 times TW, the stiffness increases, which reduces the soap-5 edge effect of the outer shoulder section in the axial direction. As a result, it is likely that transverse skidding and hiking will occur.

j The narrow perimeter shoulder groove has a GB groove width of 1.5 to 2.5 10 mm. In this example, the width is constant in the circumferential direction of the ring and in its depth direction.

The average groove depth BH of a narrow circumferential shoulder GB is 0.3 to 1.10 times the groove depth GH of the circumferential main grooves 15, preferably 0.4 to 0.7 times GH. j If the depth BH is less than 0.3 times the main groove depth! GH axially, the stiffness of the outer shoulder portion SB1 is not reduced and the resistance to skidding and hiking is reduced. If, however, the depth BH is greater than 20 times 1.10 times the depth GH of the main groove, the stiffness of the outer shoulder portion SB1 is reduced axially too much, and uneven wear is likely to occur.

· '25 In the axial direction, the outer shoulder portion SB1 is provided with: at least one edge soap ES extending in a circumferential direction parallel to the tread edge E.

In this embodiment, the two edge soaps ES and ES are: equally spaced axially in the width direction of the outer shoulder portion SB1 to divide this portion into three axial portions having substantially the same width.

The width of the edge seam ES is smaller than the width of the GB of the narrow circumferential shoulder and is between 0.2 and 1.5 mm, preferably less than 0.7 mm.

; The average depth EH of the edge seam ES is 0.25 - 1.25 »· 109006 8 times the average depth BH of the narrow circumferential shoulder GB.

In this example, EH is about 0.8 times BH.

If the depth EH is less than 0.25 times the depth BH, the axial stiffness of the outer shoulder section SB1 is reduced axially by the BH step-5 so that resistance to transverse slipping and migration is reduced. If the depth EH is greater than 1.25 times the depth BH, the stiffness decreases and the soap bottoms exhibit a tendency to form cracks, which causes the tread rubber to loosen and therefore shortens the tread life.

In this embodiment, the depth of the peripheral soap ES and the depth of the narrow j 15 circumferential shoulder GB are unchanged in their longitudinal directions. But the depth can be varied.

The tread portion 12 is further provided with a plurality of groove side grooves S disposed on at least one side of each symmetrically disposed pairwise circumferential head groove GO.

Each groove side soap S is disposed at an axial distance (1) from a circumferential main groove of 0.06 '* · * 25 to 0.25 times the tread half width TVJ.

• this

The groove side soap S extends parallel to or circumferentially inclined with the main groove GO: ·. *, Or at an angle of not more than 5 ° to the circumferential direction J J. 3 0 for the main career GO.

. In this embodiment, there are continuous straight soaps for each of the axially extending grooves G02 on each side of the groove G02, i.e. the shoulder pins; SB and the tread center pins 5; The groove side soap S on the shoulder piece SB is positioned _ · '. axially into the inner shoulder portion SB2 for further subdivision of this 109006 9 portion SB2 into a wide main portion B2 and a narrow transverse portion B1. The width SW and the depth of the groove side sink S are constant over its length, but can be varied within the corresponding spacing.

; 5

The width SW of the groove sidewall S is between 0.2 and 1.5 mm, more preferably less than 0.7 mm.

The mean depth SH of the groove side sink S is 0.25 to 1.0 times the groove depth GH of the circumferential main grooves GO. In this example, SH is about 0.5 times GH. If the depth SH is less than 0.25 times the depth GH, the resistance to transverse slipping is greatly reduced.

If the depth SH is greater than 1.0 times the depth GH pie-15, the axial stiffness of the narrow cross section B1 is increased such that resistance to transverse slipping is reduced, and tread rubber release is likely to occur, which results in reduced tread life.

20

As shown above, the circumferential length L of the narrow cross section B1 is 3.0 to 20.0 times the groove width GW of adjacent circumferential grooves G02. If the length L is less than 3.0 times the width GW, the resistance to · · '25 transverse slip is greatly reduced. If: the length L is greater than 20.0 times the width GW, while the circumferential spacing g of the axial grooves g increases, reducing grip, braking force, and dewatering.

Since the tread center buttons 5 in this embodiment are also provided with groove side nipples S, each tread center button is axially divided into a wide main section B2 and a narrow cross section B1 adjacent to the main groove G02 in a manner similar to the shoulder section. 3 5 den with SB.

. ·); In addition, each shoulder SB is provided with axial saps LS spaced circumferentially only at its wide main portion 10 109006 B2. The axial sockets LS in each main body B2 extend parallel to each other and parallel to the front / rear edges of the knobs 5 or axial grooves (g) from the narrow circumferential shoulder groove GB to the groove side seam S. Accordingly, the axial sockets LS make a bend.

It is preferred that no axial soap is formed in the axial direction on the outer shoulder portion SB1 and the narrow cross section B1 to maintain their rigidity. However, if the spacing of the axial grooves is large and therefore the length of the narrow cross-sections 15 divided by two or more can fulfill the above condition, an axial soap may be formed, for example, as shown in Figure 4. In Figure 4, only narrow | the transverse section B1 is provided with an axial socket RS at its central section.

20

In the embodiment shown in Figs. 1-3, the central wear surface knobs 4 and the tread center wear knobs 5, except for their respective narrow cross sections B1, are each provided with similarly curved axial * * '· · * 25 sipes LS extending across the knob in one direction. parallel to the axial »sliders.

* · ,. The groove side sills form one or both sides of each circumferential main groove 30 GO1 to define a narrow cross section B1 adjacent to the tread ii>; gadgets.

»K *» ·; * 'Treads of tire size 10.00R20 •: ·· * with the tread pattern shown in Figs. 1-3 were made by way of example only by varying /. The following parameters: * · 109006 11 width WSB1 of the outer shoulder portion SB1 in the axial direction; a narrow circumferential rectangular GB depth BH; 5 circumferential edge soap ES depth EH; groove side groove S groove depth SH; 10 depth gH of axial grooves (g); groove side groove S groove width SW; and the circumferential length L of the narrow cross section B1, and the ren-15 lanes were tested for transverse slipping.

The performance of each test tire in transverse skidding was assessed by a test run driving the test vehicle along an icy test track.

20

The test tire was mounted on a conventional 7.00T size rim and inflated to an internal pressure of 8.0 kg / cm2. The tire load was 2700 kg.

The test results are shown in Figures 5-9, where the results are indicated by an index. The higher the index, the better the resistance to transverse slip.

Fig. 5 is a graph illustrating transverse slip as a function of the quotient WSB1 / TW, which is the width WSB1 of the outer shoulder portion SB1 in the axial direction divided by the tread width TW. (BH / GH = 0.8 and EH / BH = 1.0) 35

Fig. 6 is a graph showing the transverse skid * | ; plotting versus BH / GH and EH / BH; quotient * 109006 12 BH / GH is the groove depth BH of the narrow circumferential shoulder groove B divided by the groove depth GH of the wide circumferential grooves G, and the quotient EH / BH is the groove depth EH of the circumferential edge groove ES divided by the narrow ol

Fig. 7 is a graph showing transverse slip as a function of the quotient SH / GH, which is the groove depth SH of the groove side sink S divided by the groove depth GH of the wide circumferential main grooves. (gH / GH = 0.8, SW = 0.6 mm and 1 / GW 1.0)

Fig. 8 is a graph showing transverse slip as a function of gH / GH, which is the depth gH of the axial grooves 15 (g) divided by the groove depth GH of the wide circumferential end grooves GO. (SH / GH = 0.8, SW = 0.6 mm and 1 / GW = 1.0)

Fig. 9 is a graph showing the transverse slip-20 width of the groove side sip S and the quotient L / GW

as a function of the circumferential length L of the narrow cross section B1 divided by the groove width GW of the wide circumferential main grooves GO.

• · • · | ) 25 Experiments confirmed that the inventive tires were superior in cross resistance to ♦ · · t '* cross-skidding.

As discussed above, the tires of the invention improve their resistance to cross-skidding when driving on snowy and icy roads while retaining traction and braking power. Further, • ·, · **, the propensity to wander due to the reduced stiffness of the tread shoulder. In addition, the axial sections of the circumferential portions of the shoulder button divided by the axial soaps are limited by the direct support provided by the circumferentially adjacent circumferential part of the shoulder, and the indirect support or its existence. , which results in uneven wear and a tendency to tear off the tread rubber to extend life.

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Claims (8)

14 109006 A pneumatic tire comprising a tread member 5 having two tread edges (E), wherein said tread member is provided with two main circumferential grooves (G02) disposed symmetrically at axial positions relative to the centerline (C) of the ring and an axial groove (g). for determining at least one circumferential tread row (CB, SB) associated with each circumferential main groove (G02), each tread segment (CB, SB) is provided with at least one sipe (S) having a width of 0.2 to 1.5 mm , and extending continuously substantially parallel to the main groove (G02) for dividing the knob (CB, SB) into a wider main area (B2) and a narrow cross section (B1) on the main axial side, characterized in that the 20 narrow cross section (B1) more than 3.0 times but less than 20.0 times the circumferential main groove (G02). groove width (GW), • · * · * "25 the average depth (SH) of each sipe (S) is 0.25 - 1.0 times * the depth of the circumferential main groove (G02) (GH),: · * the depth of the axial grooves (g) ( gH) is greater than 0.40 but less than 1.0 * 11 · 'times the groove depth (GH) of the circumferential main groove (G02) 30 1 • 1 A pneumatic tire according to claim 1, characterized in that said wide main part (B2) is - several spaced circumferentially spaced · 35 axially sided (LS) disposed axially extending 109006 15 Pneumatic tire according to claim 1 or 2, characterized in that the main circumferential grooves are straight grooves and the axial grooves make a bend. Pneumatic tire according to claim 1, 2 or 3, characterized in that said at least one row of tread tread (CB, SB) is a tread row (SB) of tread treads located axially in each of the circumferential main grooves (G02). ) outside, and a circumferential row of abutment pads (CB) inside the circumferential main groove (G02). Pneumatic tire according to claim 1, 2, or 3, characterized in that the at least one row of circumferential tread (CB, SB) is a circumferential row of tread (CB) outside each of the main circumferential grooves (G02). Pneumatic tire according to claim 1, 2 or 3, characterized in that the at least one row of circumferential tread (CB, SB) is • I:. * A circumferential row of tread (CB) which is axial to each of the main circumferential grooves. (G02): **: 25 inside. * »· * · 30 ... 1. Pneumatics däck som innefattar en slitstsdel med tvä slanttskanter (E), * I I * · · •» · Colors sagta sldtsdel är försedd med tvä peripheralella '. 35 interesudspär (G02) anordnade i symmetric axiala positioner i förhällande account däckets mittlinje (C) och axiella * »I • · i 109006 16 spär (g) för att definiera ätminstone en peripheral rad (CB, SB) slitytsblock som ansluter sig account det. peripheral-interest hub (G02), 5-pin slittsblock (CB, SB) and stock exchange med ätminstone en sajp (S) med en bredd av 0.2 account 1.5 mm och som sträcker sig continuerligt paräselllig med (G02) för att dela blocket (CB, SB) i en bredare for interest (B2) och en smal tvärdel (B1) access to periphery 10 interest interest sida, kännetecknat därav, att den smala tvärdelens (B1) periphery for slope (L) superstore re 3 , 0 gänger men mindre än 20,0 gänger spärbredden (GW) av det periferiella interesudspäret (G02)! 15 medeldjupet (SH) av var och en sajp (S) and 0.25 - 1.0 gangger djupet (GH) av det peripheralella interest (G02). djupet (gH) av de axiella spären (g) ø 0,40 20 men mind än 1,0 gänger spärdjupet (GH) av det periferiella interest (G02). ·. ·. 2. Pneumatic däck enligt patent kr av 1, kännetecknat * ·; . ·. därav, att as Breda's interests (B2) försedd med flera 25. perifeririktning päen avständ frän varandra anordnade • ·. i axialriktning sig sträckande axiella sajper (LS). \ 't 3. Pneumatic däck enligt patentkrav 1 eller 2, ankle tecknat därav, att de periferiella interesudspären är raka, 30 spär, och de axiella spären är krökta. »I ·; · * 4. Pneumatic däck enligt patentkrav 1, 2 eller 3, tilecknat därav, att like the following peripheral peripheral rad av slitstsblock (CB, SB) and peripheral rad av sli -; * · 35 tytsblock (SB) ), som befinner sig i den axiella riktningen: utanför de bäda peripheralella huvudspären (G02), samt en 109006 17 peripheral rad av slitstsblock (CB) i axiell riktning inanför det peripheralella interesudspäret (G02). 5. Pneumatic däck enligt patent krav 1, 2, eller 3, 5 kangnetecknat, därav, att sagdätminstone en rad av peripheral slittsblock (CB, SB) and peripheral rad av slittsblock (CB) utanför de bäda peripheral hood (G02) . 6. Pneumatic disk drive block 1, 2, eller 3, telescopic drive block, such as a block stone blocker (CB, SB) and a peripheral block blocker (CB), som filler sig i axiell riktning innanför de bäda (G02). 15 «· * · · * * ·» · I I I j