CN101821118B

CN101821118B - Tire

Info

Publication number: CN101821118B
Application number: CN200880111004.XA
Authority: CN
Inventors: 小盐真寿; 中村浩一
Original assignee: Bridgestone Corp
Current assignee: Bridgestone Corp
Priority date: 2007-10-10
Filing date: 2008-10-08
Publication date: 2013-02-20
Anticipated expiration: 2028-10-08
Also published as: KR101085345B1; JPWO2009048078A1; CN101821118A; WO2009048078A1; JP5276008B2; KR20100056554A

Abstract

A heavy duty pneumatic radial tire which can reduce second rib punch partial wear without spoiling wet performance and heating durability. In a rib type tread pattern pneumatic radial tire where four main grooves (1) extending along the circumference of a tire are arranged in the tread portion and five rows of land (2a-2e) are formed in the tread portion by the main grooves (1), the second rows of land (2b, 2d) from the outermost ends in the width direction of the tire out of the rows of land (2a-2e) are provided with lug grooves (5a, 5c) extending in the width direction thereof and having raised bottoms (5a', 5c') formed by raising the bottom of the groove toward the surface of the land at the end on the shoulder side, and sipes (6) are formed in the shoulder side edges of the lands (2b, 2d) at such an interval as equalizing the width direction rigidity along the circumference of the tire in regions one third from the land on the shoulder side.

Description

Tire

Technical field

The present invention relates to be suitable for being installed in the Pneumatic belt tire that uses on the vehicles such as truck, city motor bus, particularly in this tire, can effectively alleviate in the past unavoidable generation irregular wear (2nd (second) bar shaped corrugated irregular wear).

Background technology

As the Pneumatic belt tire that is installed on the heavy-duty vehicles such as truck, city motor bus, to compare driven nature poor with the air-inflation tyre with block-type tread, but straight line stability, polishing machine are good, so, used following air-inflation tyre more in the past, this air-inflation tyre is separated with many grooves along the circumferential extension of tire of compartment of terrain configuration at the Width of tyre surface, and has the tread contour of dividing the bar shaped pattern type of formation grounding parts waiting each other of above-mentioned many grooves.

But for this air-inflation tyre, the second grounding parts is compared and can be worn and torn in advance with other grounding parts from the Width outermost end of tire, can't avoid so-called the second bar shaped corrugated irregular wear, requires to alleviate this irregular wear.

About this point, proposition has following technology, that is, be provided with circumferential continuous stria along tire at the tire shoulder side edge part of the bar shaped decorative pattern of an inboard that is positioned at tire shoulder bar shaped decorative pattern, form the slice shape decorative pattern that has with the bar shaped decorative pattern main body equal height of being divided by this stria.(for example, with reference to patent documentation 1)

Patent documentation 1: Japanese kokai publication hei 5-246213 communique

; above-mentioned technology in the past is by making selectively the wearing and tearing of slice shape decorative pattern; thereby the technology of the irregular wear when suppressing initial wear is difficult to form until the whole zone of wear on tyres later stage tire width direction keeps the state of uniform wear always.

In addition, in order to alleviate the second bar shaped corrugated irregular wear, it is favourable not forming the cros-rib tread groove that has along the marginal element that the Width of tire extends at this grounding parts (the second bar shaped decorative pattern), but in this case, because can't avoid the reduction of wetland performance, heating durability, so can not say useful method.

Summary of the invention

Problem of the present invention is to provide a kind of new heavy duty to reuse Pneumatic belt tire, in the air-inflation tyre of the tread contour with bar shaped pattern type, can alleviate in the past inevitable the second bar shaped corrugated irregular wear, can form until use the later stage to make the whole zone of tire width direction carry out uniform wear always.

The present invention is that Pneumatic belt tire is reused in a kind of heavy duty of tread contour of bar shaped pattern type, be provided with along at least three major troughs of the circumferential extension of tire at fetus face, be listed as at the grounding parts that this fetus face forms more than four row by above-mentioned major trough, it is characterized in that, in above-mentioned grounding parts row, the grounding parts of secondary series is provided with the cros-rib tread groove from the Width outermost end of tire, this cros-rib tread groove extends along the Width of the grounding parts of above-mentioned secondary series, and, has bottom land in the end of tire shoulder side towards the grounding parts surface and the protruding bottom of protuberance, tire shoulder side edge part at this grounding parts is arranged with tire sipe, and this tire sipe makes the Width rigidity in zone of this grounding parts tire shoulder side 1/3 along the circumferential formation uniform state of tire.

At this, about the cros-rib tread groove, so-called " Width along grounding parts extends " refers to compare with the circumferential development length of tire, and the development length of tire width direction is long.

Reuse in the Pneumatic belt tire 15～25% of width preferred above-mentioned protruding bottom, that on the Width of this grounding parts, be of a size of this grounding parts in the heavy duty that forms above-mentioned formation.

In addition, above-mentioned protruding bottom has 60～100% bump height of the groove depth of cros-rib tread groove, the number of above-mentioned major trough is four, the width of the grounding parts of this secondary series is 1.0～1.1 times of width of grounding parts that are positioned at the Width central portion of tire, and the grounding parts that is positioned at the tire width direction outermost end has 1.2～1.4 times width of the grounding parts that is positioned at the Width central portion.

In addition, angle of inclination protruding bottom, circumferential with respect to tyre surface of preferred cros-rib tread groove is 70～90 ° scope, and the bending part more than the place preferably is set in being provided with this cros-rib tread groove of protruding bottom.

In addition, in above-mentioned any tire, preferably in the cross section of the tread width direction of the outermost tire shoulder major trough that is positioned at the tread width direction, at the tire shoulder major trough, and and the inboard adjacent inboard major trough of the tread width direction of this tire shoulder major trough between the grounding parts near surface part of cell wall of the grounding parts side of dividing with respect to the angle of this grounding parts normal to a surface direction, less than the cell wall of this grounding parts side than this grounding parts near surface part near the angle of the inside side's side part in the footpath of the inside side's side in footpath with respect to this grounding parts normal to a surface direction, in this case, make the grounding parts near surface part of 25～30% the scope that plays the tire shoulder major trough degree of depth from the grounding parts surface of above-mentioned cell wall with respect to the angle of grounding parts normal to a surface direction, less than above-mentioned cell wall than this grounding parts near surface part near the angle of the inside side's side part in the footpath of the inside side's side in footpath with respect to grounding parts normal to a surface direction, the grounding parts near surface of preferred above-mentioned cell wall part is the value in 0～7 ° the scope with respect to the above-mentioned angle of grounding parts normal to a surface direction, above-mentioned cell wall be value in 10～20 ° the scope with respect to the above-mentioned angle of grounding parts normal to a surface direction near the inside side's side part in the footpath of the inside side's side in footpath than this grounding parts near surface part.

The grounding parts of secondary series is provided with the cros-rib tread groove from the Width outermost end of tire, this cros-rib tread groove extends along the Width of the grounding parts of above-mentioned secondary series, and, has bottom land towards the protruding bottom of grounding parts surface elevation in the end of tire shoulder side, tire shoulder side edge part at this grounding parts is formed with tire sipe, this tire sipe configuration space so that the Width rigidity in the zone of this grounding parts tire shoulder side 1/3 along tire circumferentially evenly, thereby make the rigid uniform of the grounding parts at this position, do not damage the wetland performance, heating durability ground alleviates the second bar shaped corrugated irregular wear.

Description of drawings

Fig. 1 is the local expansion planar view of the tread contour of expression Pneumatic belt tire of the present invention.

Fig. 2 is the figure in the X-X cross section of presentation graphs 1.

Fig. 3 is the figure of the relation of expression rigid circumference and circumferential position.

Fig. 4 is the figure of expression another embodiment of the present invention.

Fig. 5 is the amplification sectional elevation of middle ground section.

Fig. 6 is the amplification cross-sectional plane of tire shoulder major trough.

Description of reference numerals

1, major trough; 1a, cell wall; 2a～2e, grounding parts; 3, tire shoulder section; 4, sidewall section; 5a～5c, cros-rib tread groove; 5a ', 5c ', protruding bottom; 6, tire sipe; 9, dogleg section; 10, stone release section; 11, protruding bottom; E, tyre surface bottom; θ, angle of inclination; E, length; D, highly; W, grounding parts width; H, cros-rib tread groove depth; D, the major trough degree of depth; α, β, angle; ρ, grounding parts near surface part.

The specific embodiment

Below, use accompanying drawing to more specifically describe the present invention.

Fig. 1 is the local expansion planar view of the tread contour of expression embodiments of the present invention, and Fig. 2 is the figure in the X-X cross section of presentation graphs 1.

Reference numeral 1 expression in the accompanying drawing is formed on the tyre surface tread, and four major troughs in the figure of the circumferential extension of tire, Reference numeral 2a～2e divides to be formed at major trough 1 each other, and at the outermost tire shoulder major trough 1 of tread width direction and the grounding parts between the tyre surface lateral margin, Reference numeral 3 is tyre surface tire shoulder sections, Reference numeral 4 is to be communicated with the sidepiece separately of fetus face, and radius vector is the sidewall section of side's extension inwardly, Reference numeral 5a～5c is respectively formed on grounding parts 2b～2d, and extend along the Width of this grounding parts 2b～2d, and along each cros-rib tread groove that circumferentially this grounding parts 2b～2d is demarcated of tire.

At this, so-called " tyre surface tread ", refer to tire is installed on the applicable wheel rim, and under the state of the air pressure that is filled with regulation, with this tire with the vertical position rest configuration on flat board, and when this tire applied the load corresponding with the quality of stipulating, tire and the dull and stereotyped face that contacts.

In this case, so-called " applicable wheel rim ", refer to the size according to tire, by the wheel rim of following prescribed by standard, so-called " air pressure of regulation " refers in following standard, corresponding with the maximum load ability and the regulation air pressure, so-called maximum load ability refers to tire be allowed the quality of the maximum that applies in following standard.In addition, so-called " quality of regulation " refers to above-mentioned maximum load ability.

In addition, said air also can replace with non-active gas or other the gases such as nitrogen here.

In addition, so-called standard, refer at the regional actv. industrial standard of producing or use tire, for example be " the YEAR BOOK of THE TIRE AND RIM ASSOCIATIONINC. " in the U.S., being " the STANDARDS MANUAL of THE European Tyre and RimTechnical Organisation " in Europe, is Japanese car tire association " JATMA YEAR BOOK " in Japan.

Among above-mentioned grounding parts 2a～2e, from the Width outermost end of tire cros-rib tread groove 5a, the 5c of grounding parts 2b, the 2d of secondary series, its groove depth is constant, and have the bottom land that extends with the outside face almost parallel ground of grounding parts, being provided with in the end of tire shoulder side and making bottom land is that d and the length on the Width of

grounding parts

2b, 2d are protruding bottom 5a ', the 5c ' of e towards the height of

grounding parts

2b, 2d surface elevation.

In addition, Reference numeral 6 is tire sipes of being located at the tire shoulder side edge part of grounding parts 2b, 2d.This tire sipe 6 is configured with interval t, make this

grounding parts

2b, 2d tire shoulder side 1/3 the zone Width rigidity along tire circumferentially evenly.

Inevitable the second bar shaped corrugated irregular wear that produces in the air-inflation tyre of the tread contour with bar shaped pattern type is produced by following situation: the initial stage that is beginning to travel, produce toe and heel wearing and tearing at the second bar shaped decorative pattern, afterwards, wearing and tearing develop into the side of entering into from the side of pedaling out of tire shoulder side, and then develop into reverse wearing and tearing, in order to suppress the second bar shaped corrugated irregular wear, the starting point of eliminating the wearing and tearing of toe and heel is special actv., as its method, at the grounding parts 2b of secondary series, the upper setting of 2d has protruding bottom 5a ', the cros-rib tread groove 5a of 5c ', 5c.

If the height d of protruding bottom 5a ', 5c ' is low, then can't improve fully the rigidity at this position, can't embody the effect of bringing by protruding bottom is set, so the bump height of protruding bottom 5a ', 5c ' is preferably 60～100% the scope of the groove depth h of cros-rib tread groove.

In addition, if length e protruding bottom, the grounding parts Width is short, then the rigidity of protruding bottom is excessively low, might produce the crack at this, on the other hand, on the contrary in the situation that this length e is long, the marginal element of extending along the Width of tire becomes very few, can't avoid the wetland reduction of performance, thus the length e of protruding bottom be preferably grounding

parts

5a, 5c width W 15～25%.

For example by following formula obtain grounding parts, Width rigidity G is (take the length of grounding parts as 1, calculate the rigidity of each unit), as shown in Figure 3, as long as so that the Width rigidity in the zone of the tire shoulder side 1/3 of this

grounding parts

2b, 2d arranges the interval t (it is constant making sectional area) of tire sipe 6 along the circumferentially uniform mode of tire, thus, can seek the uniformization of grounding parts rigidity of the tire shoulder side of the second bar shaped decorative pattern.Consider that interval t arranges the cut-in length S (with reference to Fig. 1) of tire sipe 6.

Formula 1

G = 2 K \cdot E \cdot \frac{{bL}^{3}}{H^{3}} \frac{1}{(1 + 3.9 \frac{L^{2}}{H^{2}})}

G: the shear rigidity (N/mm) before and after the piece

L: block length (length between the tire sipe) (mm)

B: piece width (mm)

H: tile height (mm)

E:0.36 * (100% modulus of applicable rubber)/(100% modulus of standard rubbers) (MPa)

K: coefficient of correction

When the number of above-mentioned major trough is four, the width of preferred this

grounding parts

2b, 2d is 1.0～1.1 times of width of grounding parts 2c that are positioned at the Width central portion (on the equatorial plane) of tire, and the width that is positioned at grounding parts 2a, the 2e of tire width direction outermost end is 1.2～1.4 times of the width of the grounding parts 2c that is positioned at Width central portion (on the equatorial plane).

Its reason is, the input of the input ratio Width central portion side force of the side force of the Width outermost end of tire is large, so the width of grounding parts 2a, the 2e of the Width outermost end of tire is the widest, next order by the grounding parts 2c of this

grounding parts

2b, 2d, central portion in turn arranges width, can make each grounding parts rate of wear even.

Fig. 4 is the part sectional view of the Width of the local expansion figure of tread contour of expression another embodiment of the present invention and tire.

At this, be formed with four major troughs 1 that extend continuously along circumferential linearly at the tyre surface tread, between above-mentioned major trough and between the outermost tire shoulder major trough 1 and tyre surface lateral margin E in the tread width direction, master plan is told the grounding parts 2a～2e of five row, at the 2c of center-point earth section, form many in the drawings to the upper right side to extend steppedly along circumferentially being separated with the compartment of terrain, and cross the ladder cros-rib tread groove 5b of the 2c of this center-point earth section fully, in addition, at each 2b of middle ground section that is positioned at center-point earth section 2c adjacent position, 2d, form many bending cros-rib tread groove 5a along circumferentially being separated with the compartment of terrain, 5c, these many bending cros-

rib tread groove

5a, 5c is at this central authorities' major trough 1 opening, from this opening part to upper right or to left down all linearly extensions in angle of inclination circumferentially to equate with respect to tyre surface, and, near zone from outermost tire shoulder major trough 1, the groove edge of tire shoulder major trough 1 for example, once be bent into roughly " ヘ word shape " with the width in 50～70% the scope of middle ground section width W, and to this tire shoulder major trough 1 opening.

At this, angle of inclination dogleg section 9, circumferential with respect to tyre surface of each bending cros-rib tread groove 5a, the 5c that forms at each 2b of middle ground section, 2d can also be made as mutual different angle except all being made as the identical angle like that as shown.And, be each bending cros-rib tread groove 5a, the 5c in place bending in the drawings, also can be with each bending cros-

rib tread groove

5a, 5c in the bending of a plurality of positions.In addition, Reference numeral 10 expression is made of the square protrusion of the bottom land that is formed on central major trough 1 among the figure, prevent that stone from embedding the stone release section of usefulness.

And, at this, in the tire shoulder major trough one side part of each bending cros-

rib tread groove

5a, 5c, form the protruding bottom 11 make the bottom land protuberance and to form, tilt angle theta line of centers, circumferential with respect to tyre surface that makes each protruding bottom 11 or this each protruding bottom 11 is in 70～90 ° the scope.

At this bending cros-

rib tread groove

5a, 5c can prevent the irregular wear of tire shoulder side end, and, can guarantee the length of cros-rib tread groove and make tire have excellent wetland performance, in addition, bending cros-rib tread groove 5a, the above-mentioned tilt angle theta of 5c has been guaranteed the cros-rib tread groove significantly, the Width of tire and circumferential marginal element, realize excellent wetland performance, in addition, in order to prevent by cros-

rib tread groove

5a, 5c is at grounding parts 2b, formation easily becomes the acute angle corner portions of the core of irregular wear in the 2d, at this above-mentioned tilt angle theta is selected in 70～90 ° scope.

Even increase the tilt angle theta of cros-rib tread groove, as long as by the mode with the core that do not form irregular wear bending part is set, just can guarantee θ=70～90 °.

Namely, the angle of inclination circumferential with respect to tyre surface of protruding bottom 11 is in 70～90 ° the scope, by further raising bending cros-

rib tread groove

5a, 5c, between the cros-rib tread groove of the opening portion of tire shoulder major trough 1 rigidity of part, thereby can further effectively prevent from partly producing bar shaped corrugated irregular wear at this grounding parts.

In the situation that this angle of inclination is less than 70 °, can't be with bending cros-rib tread groove 5a, the rigidity of the acute angle corner portions of the grounding parts of the opening portion of 5c is brought up to desired degree, and carry out irregular wear with this acute angle corner portions as core, so at bending cros-rib tread groove 5a, protruding bottom 11 is set on the 5c, seek the uniformization of the Width rigidity of grounding parts part, in addition, with cros-rib tread groove 5a, the open end portion of 5c produces bar shaped corrugated irregular wear as core, even be in 100% the situation of cros-rib tread groove depth in the bump height of protruding bottom 11, also because protruding bottom weares and teares gradually through using, so can produce equally bar shaped corrugated irregular wear.

This protruding bottom 11 also as described above, as the cross-sectional view of the illustrative middle ground 2b of section of Fig. 5,2d, the Width of preferred this

grounding parts

2b, 2d, size e is in 15～25% the scope of width W of the 2b of middle ground section, 2d, and bump height d protruding bottom 11, from bottom land is in 60～100% the scope of groove depth h of rake 9 of bending cros-

rib tread groove

5a, 5c.

And in this tire, edge in tire shoulder major trough 1 side of the 2b of middle ground section, 2d, set many tire sipe 6 that broad ways is extended with the posture of extending to the Width of

grounding parts

2b, 2d, the mode that in this grounding parts, stops, the Width rigidity that this tire sipe of many 6 makes zone this grounding

parts

2b, 2d, tire shoulder side 1/3 tyre surface week upwards evenly.

The tire sipe 6 of this situation set the interval also as described above, particularly at the bending cros-rib tread groove 5a that is applied to be provided with protruding bottom 11, in the situation of 5c, if uniformly-spaced to form tire sipe 6, grounding parts 2b then, the Width rigidity of 2d is at bending cros-

rib tread groove

5a, 5c's, diminish near the part open end of tire shoulder major trough 1 opening, become inhomogeneous at tyre surface Zhou Fangxiang, so about the bending cros-rib tread groove Width rigidity of section part indirectly, can be based on above-mentioned (formula 1), obtain from tire shoulder major trough 1 side until the rigidity in 1/3 the scope of the width of this grounding parts part, by so that this Width rigidity is determined indirectly section's Width rigidity partly of bending cros-rib tread groove at the interval that the uniform mode that makes progress in tyre surface week is set tire sipe.

In addition, in position shown in Figure 4, except the edge of central major trough 1 side of the 2b of middle ground section, 2d, also form respectively the short size tire sipe 13,14 that extends along the grounding parts Width in two edges of center-point earth section 5, these tire sipes 13,14 are in the present invention not necessarily.

But, as shown in Figure 4, divided in the tire of grounding parts 2a～2e that five row are arranged at the tyre surface tread by four major troughs 1, also as described above, the width of the preferred 2b of middle ground section, 2d is in 1.0～1.1 times the scope of width of the 2c of center-point earth section, and the width that is divided in outermost tire shoulder grounding parts 2a, the 2e of tread width direction is in 1.2～1.4 times the scope of width of the 2c of center-point earth section.

In addition, preferably, in the tread width direction cross section of tire shoulder major trough 1, such as Fig. 6 with as illustrated in the amplification view, the grounding parts near surface of the cell wall 1a of the 2b of middle ground section, 2d side part is with respect to the angle α of the 2b of middle ground section, 2d normal to a surface n direction, than the cell wall 1a of the 2b of middle ground section, 2d side partly to compare the radially inner side part of more close radially inner side little with respect to the angle β of the 2b of middle ground section, 2d normal to a surface n direction with the grounding parts near surface.

Thus, near rigidity part tire shoulder major trough 1 of the 2b of middle ground section, 2d is reduced, this part easily is out of shape when loading of tire rotates, part is is roughly worn and torn equably along the circumferential integral body of tire near making this, can more effectively be suppressed at thus near this part and produce bar shaped corrugated irregular wear.

But, make that cell wall 1a's play grounding parts near surface part p in 25～30% the scope of depth D of tire shoulder major trough 1 with respect to the angle of grounding parts normal n from the grounding parts surface, different with the inside side's side part in footpath with respect to the inside side's side in the close footpath of this grounding parts near surface part p of cell wall 1a, preferred grounding parts near surface part p with respect to this angle α of grounding parts normal n less than the angle β of the inside side's side part in its footpath with respect to grounding parts normal n, more preferably grounding parts near surface part p is 0～7 ° with respect to the angle α of grounding parts normal n, and the inside side's side part in its footpath is 10～20 ° with respect to the angle β of grounding parts normal n.

Like this, by making above-mentioned angle α, grounding parts near surface part p and the footpath inside side side part of this grounding parts near surface part p of β in 25～30% scope of the depth D that plays the tire shoulder major trough from the grounding parts surface is different, the inside side's side in footpath at this grounding parts near surface part p partly increases in the situation of angle, utilize the reduction of the rigidity of grounding parts part, can effectively tackle at the initial stage of wearing and tearing grounding parts near surface and produce toe and heel wearing and tearing.

In addition, at this, making grounding parts near surface part p is 25～30% scope of tire shoulder major trough depth D, and irregular wear becomes problem especially in the time of in above-mentioned scope.

Grounding parts near surface part p be less than tire shoulder major trough depth D 25% the time owing to can't cover fully the generation scope of irregular wear, so the possibility that produces irregular wear is still arranged.

With respect to this, if greater than 30%, then basically do not worry irregular wear, than 30% darker degree of depth part, can seek the uniformization of rigidity of grounding parts of the both sides of tire shoulder major trough 1, suppress preferably wearing and tearing.

That is, when in greater than 30% scope of tire shoulder major trough depth D the cell wall angle being applied relative mistake, wearing and tearing become and easily carry out, and wear-out life reduces.

And, this above-mentioned angle α, β are made as the grounding parts near surface be in 0～7 ° the scope value, be more remarkable in the situation in 10～20 ° the scope than grounding parts near surface by the part of the inside side's side in footpath.

Embodiment 1

Make following tire, namely, (well width is 13mm to have four major troughs, the degree of depth is 15mm), the width of the second grounding parts is 32mm, the well width of cros-rib tread groove is 3mm, the degree of depth is 3mm, the height d of protruding bottom is 3mm, the length e of protruding bottom is 5mm, (length of protruding bottom)/(the width w of the second grounding parts) is 16%, (the height d of protruding bottom)/(the cros-rib tread groove depth h of the second grounding parts) is 100%, and, with interval 9.6mm (t1), 12.6mm (t2) the configuration A/F is 2.5mm, the degree of depth is the tire sipe of 13mm, and bar shaped decorative pattern width be distributed as the C/L of tyre surface central authorities: second: the tire shoulder side is the TBR tire (being fit to tire) of 1: 1.05: 1.24 size 11R22.5, attach it to and be of a size of on 8.25 * 22.5 the wheel rim, be installed with in inciting somebody to action and be 800kPa, carry out the irregular wear characteristic, the wetland performance, the test of heating durability, carried out (not having protruding bottom with in the past tire, tire sipe is spaced apart 9.4mm uniformly-spaced, and is in addition identical with suitable tire) relatively investigation.

In addition, for the irregular wear characteristic, above-mentioned tire is installed on the car of actual use, make it after asphalt road travels about 50000km, height residual quantity with the bar shaped corrugated irregular wear of the second grounding parts compares, the above-mentioned tire that the wetland performance is identical is installed on the car of actual use, brake on being covered with the road surface of iron plate, travelling with 20km/h, compare with its stopping distance, in addition, for the heating durability, above-mentioned tire is carried out the indoor testing drum (diameter of cylinder of applicable cylinder: 1.707m, speed: 65km/h, load: standard 100% during beginning, every 6h increase respectively normal loading 10%), it is travelled until produce fault, the used time is compared.

Its result, confirm as follows: for irregular wear, in the situation that tire in the past, the height residual quantity is 3mm, finds to produce bar shaped corrugated irregular wear in being fit to tire.In addition, for the wetland performance, tire, suitable tire all were 100% in the past, did not have large difference; For the heating durability, in the situation that tire was 32 hours in the past, suitable tire is 33 hours, and can keep this performance.

Embodiment 2

For the embodiment tire that is of a size of TBR295/80R22.5 and comparative example tire I～III, anti-irregular wear, wetland performance and heating durability test have been carried out respectively.

The embodiment tire has tread contour as shown in Figure 4, the 2b of middle ground section, the width W of 2d is 33mm, bending cros-rib tread groove 5a, the degree of depth h of 5c is 2mm, the tilt angle theta circumferential with respect to tyre surface of protruding bottom 11 is 75 °, at above-mentioned bending cros-rib tread groove 5a, 5c's, position apart from tyre surface central portion side 20.8mm is provided with " ヘ word shape " bending part, protruding bottom 11, grounding parts 2b, the length e of the Width of 2d is 5mm, this length e's of protruding bottom 11, ratio with respect to middle ground section width W is 15%, the bump height d of protruding bottom 11 is 2mm, this height d's, ratio with respect to tipper degree of depth h is 100%, and, the 2b of middle ground section, 2d's, the tire sipe of the lateral margin of all groove 1 sides of tire shoulder is spaced apart 10.3mm and (does not separate cros-rib tread groove 5a, the part of 5c9) and 13.7mm (separate cros-rib tread groove 5a, the part of 5c), the A/F of each tire sipe 6 and length are respectively 2.5mm and 10mm, and each grounding parts 2c, 2b-2d, the width of 2e is central authorities: the centre: the tire shoulder side is 1: 1.05: 1.36.

And, such as Fig. 6 with shown in the solid line, the cell wall 1a of major trough 1 with respect to the angle of grounding parts normal n at grounding parts near surface part p less than the angle of the inside side's side part in footpath with respect to grounding parts normal n.

More specifically, in position shown in Figure 6, D is that 16.3mm, p are that 5.0mm, α are 5.0 °.

Comparative example tire 1 has the structure identical with the embodiment tire except the protruding bottom angle of inclination circumferential with respect to tyre surface is 30 ° of these points.

Comparative example tire 2 has the structure identical with the embodiment tire except the tire sipe interval of the lateral margin of the tire shoulder major trough side of middle ground section is this point of 10.1mm.

Comparative example tire 3 is not except arranging protruding bottom on bending cros-rib tread groove, and the dogleg section of the above-mentioned cros-rib tread groove angle of inclination circumferential with respect to tyre surface be outside 30 ° of these points, has the structure identical with the embodiment tire.

At this, each tire sets installed on 9.00 * 22.5 the wheel rim, and fill the air pressure of 850kPa, be installed on the car of actual use, after asphalt road travels 50000km, measurement is estimated anti-irregular wear in toe and heel wear height residual quantity that middle ground section produces.

In addition, under these conditions each tire is installed on the car of actual use, is being covered with on the road surface of iron plate, measure the speed of a motor vehicle from 20km/h to the stopping distance that stops, the wetland performance is estimated.

In addition, under these conditions each tire is used for indoor cylinder (diameter: 1.707m) experimental engine, make it carry out load with the speed of 65km/h and roll, obtain until produces the time of fault, durability is estimated to generating heat.

In addition, for the load of tire, be by 100% of the maximum load ability of JATMA prescribed by standard in the zero hour, whenever increase by 10% through 6 hours load.

Above-mentioned test results is illustrated in table 1.

Table 1

	The embodiment tire	Comparative example tire 1	Comparative example tire 2	Comparative example tire 3
					Anti-irregular wear	Nothing	2mm	2mm	3mm
Wetland performance (numerical value is the smaller the better)	100	102	102	100
					Heating durability (time)	33	32	33	31

According to table 1 as can be known, the embodiment tire can be guaranteed excellent wetland performance and heating durability, and can effectively improve anti-irregular wear performance.

Claims

1. a tire is the tire with tread contour of bar shaped pattern type, is provided with along at least three major troughs of the circumferential extension of tire at fetus face, is listed as at the grounding parts that this fetus face forms more than four row by above-mentioned major trough, it is characterized in that,

In above-mentioned grounding parts row, the grounding parts of secondary series is provided with the cros-rib tread groove from the Width outermost end of tire, this cros-rib tread groove extends along the Width of the grounding parts of above-mentioned secondary series, and, have bottom land towards the protruding bottom of grounding parts surface elevation in the end of tire shoulder side

Tire shoulder side edge part at the grounding parts that is provided with this cros-rib tread groove is arranged with tire sipe, and the Width rigidity in zone that this tire sipe makes this grounding parts tire shoulder side 1/3 circumferentially is uniform state along tire.

2. tire according to claim 1,

Above-mentioned protruding bottom, the size on the Width of this grounding parts be this grounding parts width 15 ~ 25%.

3. tire according to claim 1 and 2,

Above-mentioned protruding bottom has 60 ~ 100% bump height of the groove depth of cros-rib tread groove.

4. tire according to claim 1 and 2,

The number of above-mentioned major trough is four, the width of above-mentioned grounding parts is 1.0 ~ 1.1 times of width of grounding parts that are positioned at the Width central portion of tire, and the grounding parts that is positioned at the tire width direction outermost end has 1.2 ~ 1.4 times width of the grounding parts that is positioned at the Width central portion.

5. tire according to claim 1 and 2,

The protruding bottom of the cros-rib tread groove angle of inclination circumferential with respect to tyre surface is 70 ~ 90 ° scope.

6. tire according to claim 1 and 2,

Bending part more than one place is set in being provided with the cros-rib tread groove of protruding bottom.

7. tire according to claim 1 and 2,

Cross section in the tread width direction of the outermost tire shoulder major trough that is positioned at the tread width direction, the tire shoulder major trough and and the inboard adjacent inboard major trough of the tread width direction of this tire shoulder major trough between the grounding parts near surface part of cell wall of the grounding parts side of dividing with respect to the angle of this grounding parts normal to a surface direction, less than the cell wall of this grounding parts side than this grounding parts near surface part near the angle of the inside side's side part in the footpath of the inside side's side in footpath with respect to this grounding parts normal to a surface direction.

8. tire according to claim 7,

Make the grounding parts near surface part of 25 ~ 30% the scope that plays the tire shoulder major trough degree of depth from the grounding parts surface of above-mentioned cell wall with respect to the angle of grounding parts normal to a surface direction, less than above-mentioned cell wall than this grounding parts near surface part near the angle of the inside side's side part in the footpath of the inside side's side in footpath with respect to grounding parts normal to a surface direction.

9. tire according to claim 7,

The grounding parts near surface of above-mentioned cell wall part is the value in 0 ~ 7 ° the scope with respect to the above-mentioned angle of grounding parts normal to a surface direction, above-mentioned cell wall be value in 10 ~ 20 ° the scope with respect to the above-mentioned angle of grounding parts normal to a surface direction near the inside side's side part in the footpath of the inside side's side in footpath than this grounding parts near surface part.

10. tire according to claim 8,