CA2079712A1 - Pneumatic tire - Google Patents
Pneumatic tireInfo
- Publication number
- CA2079712A1 CA2079712A1 CA002079712A CA2079712A CA2079712A1 CA 2079712 A1 CA2079712 A1 CA 2079712A1 CA 002079712 A CA002079712 A CA 002079712A CA 2079712 A CA2079712 A CA 2079712A CA 2079712 A1 CA2079712 A1 CA 2079712A1
- Authority
- CA
- Canada
- Prior art keywords
- axially
- tread
- axial
- circumferential groove
- sipes
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/03—Tread patterns
- B60C11/11—Tread patterns in which the raised area of the pattern consists only of isolated elements, e.g. blocks
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/03—Tread patterns
- B60C11/12—Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Tires In General (AREA)
- Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
- Acyclic And Carbocyclic Compounds In Medicinal Compositions (AREA)
- Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A pneumatic tire which has: a squared tire shoulder; a convex tread profile having a radius of curvature of 450 to 800 mm; each tread shoulder provided with an axially outer row of outer shoulder blocks between the tread edge and an axially outer narrow circumferential groove , a middle row of middle shoulder blocks between the axially outer narrow circumferential grooves and an axially inner narrow circumferential grooves and an axially inner row of inner shoulder blocks between the axially inner narrow circumferential groove and an axially outermost wide main circumferential groove each of the inner shoulder blocks provided with at most five axial sipes including a discontinuous axial sipe extending discontinuously between the axially outermost wide main circumferential groove and the axially inner narrow circumferential groove , and a continuous axial sipe extending continuously from the axially outermost wide main circumferential groove to the axially inner narrow circumferential groove ; and the spaces between the axial sipes being 8 to 16 mm,
A pneumatic tire which has: a squared tire shoulder; a convex tread profile having a radius of curvature of 450 to 800 mm; each tread shoulder provided with an axially outer row of outer shoulder blocks between the tread edge and an axially outer narrow circumferential groove , a middle row of middle shoulder blocks between the axially outer narrow circumferential grooves and an axially inner narrow circumferential grooves and an axially inner row of inner shoulder blocks between the axially inner narrow circumferential groove and an axially outermost wide main circumferential groove each of the inner shoulder blocks provided with at most five axial sipes including a discontinuous axial sipe extending discontinuously between the axially outermost wide main circumferential groove and the axially inner narrow circumferential groove , and a continuous axial sipe extending continuously from the axially outermost wide main circumferential groove to the axially inner narrow circumferential groove ; and the spaces between the axial sipes being 8 to 16 mm,
Description
--" 2~7971,~
The present invention relates to a pneumatic tire having an improved tread pattern and squared shoulders, in which uneven tread wear is reduced and at the same time lateral skid and wandering are prevented to improve running performance on the snowy roads.
Recently, in order to prevent dust pollution, studless t-ires for used on snowy and-lcy-roads are going to be brought into greater use for heavy duty vehicle e.g.
truck and bus, instead of spike tires.
In the studless tires, block tread patterns are widely used to obtain a large traction and a large braking force.
In general, in order to improve traction and braking force, the tread blocks are provided with axial sipes so as to divide each block into comparatively small independent tread elements As the resultant small tread elements are easily moved during running, uneven wear is liable to occur, and the elements are liable to be torn o~f.
On the other hand, on the snowy roads, squared shoulders can provide a great lateral road grip than sipes.
However, such squared shoulders are liable to cause wondering of the vehicle during running on the well-paved roads but having shallow ruts.
To reduce wondering by decreasing the tread shoulder rigidity, the upper sidewall part is provided with a narrow circumferential groove This , ~ ~
~ 2~797-~2 groove can not prevent lateral skid on the snowy/icy roads.
To decrease the tread shoulder rigidity, the number of axial sipes are increased. In this case, ~-uneven wear and tear-off are increased, and lateral skid can not prevented. -Japanese Patent Publicatlon (KOKAI) No 56-21gO5 discloses a tire having shoulder blocks provided with two axia~~sipes - lextendlng continuously -across the whole axial width of the block-, and one narrow groove extending continuously~across the whole circumferential length of the block. In this case, the tread elements adjacent to the tread edge are liable to be torn off, and uneven wear and lateral skid are not fully prevented.
It is therefore, an object of the present invention to provide a pneumatic tlre having squared shoulders, in which by using a discontinuous sipe or narrow groove and then speciflcally defining the position, si2e, number and the like, lateral skid on the snowy roads and wondering on the well-paved roads are reduced without sacrificing a resistance to uneven wear and a resistance to tear-off.
Accordlng to one aspect of the present lnvention, a pneumatic tire comprising, a tread portion having a pair o-f tread edges, and a buttress portion e~tending radially inwardly from each of the tread edges forming a radially outer part of each tire sidewall, , .
' 2~7~7~2 the tread portion provided with an axially outermost wide main circumferential groove extending continuously in the ~ire circumferential direction and located on each side of the tire equator at a distance of 0.2 to 0.3 times the tread width from the tire equator, - two narrow circumferential grooves extending in the tire circumferential direction and located between the axially outermost wide main circumferential groove and the tread edge the two narrow circumferential grooves located within a tread edge region defined between an axially outer position spaced apart from the tread edge by a distance of 3 to 6 mm and an axially inner position spaced apart from the tread edge by a distance of 0.0~ to 0.1 times the tread width and circumferentially spaced axial grooves extending from the axially outermost wide main circumferential groove to the tread edge thereby forming circumferentially divided three rows of blocks in each tread shoulder portion the three rows of blocks being an axially inner row of inner shoulder blocks between the axially outermost wide main circumferential groove and the axially inner narrow circumferential groove a middle row o~ middle shoulder blocks 2~797~,~
between the two narrow circumferential grooves and an axially outer row of outer shoulder blocks between the axially outer narrow circumferential groove and the tread edge ~ .;
the tread portion provided with a convex profile, the :~
convex profile extending from one tread edge to the other - tread edge and having a radius of curvature -~of 45-O to -800 mm, the buttress portion provided with a concave profile intersecting with the convex profile of the tread portion at the tread edge to form a squared or angled tire shoulder, each of` the inner shoulder blocks provided with axial sipes the axial sipes including a discontinuous axial sipe extending discontinuously in the tire axial direction between the ~axially outermost wide main circumferential groove and the axially inner narrow circumferential groove and a continuous axial sipe extending continuously from the axially outermost wide main circumferential groove to the axially inner narrow circumferential groove~ , the number of the axial sipes in each of the inner shoulder blocks being not more than five, and the space between the axial sipes being 8 to 16 mm.
- - , 2~7~7~
.
In the accompanying drawings:
Fig.l is a developed plan view showing the tread portion of a truck/bus tire according to the present invention;
: .. . . . .. .
Fig.2 is a cross sectional view taken along the line X-X of Fig.l;
- ~ Fig;3 is a enlarged perspective view showing a tread shoulder region thereof;
Fig.4 is a- enlarged cross sec.tional view showing the narrow circumferential grooves;
Figs.5(A)-(C) are plan views showing other examples of the narrow circumferential groove;
Fig.6 is a perspective view of the tread shoulder region of another embodiment of the present invention; and Fig.7(A) is a graph showing relationship between camber thrust and camber angle and Fig.7~) is a diagram e~plaining the camber thrust and camber angle;
Figs.8(A)-(C) are perspective views showing prior art.
Before describing various embodiments of the invention, a description of the prior art shown in Figs 8(A)-(c) will be given.
: ~ :
In general, in order to improve traction and braking-force, the tread blocks (a) are provided with axial sipes (s) so as to divide each block into comparatively small independent tread elements, for example as shown in Figs.8(A)-(C).
, . .
, 2~7~7~ 2 .
As the resultant small tread elements are easily moved during running, uneven wear is liable to occur? and the elements are liable to be torn off.
On the other hand, on the snowy roads, squared shoulders can provide a great lateral road grip than sipes.
However, such squared shoulders are liable t:o cause wondering of- khe vehicle during running on the well-paved roads but having shallow ruts. - ~ -In Fig.8(A), to reduce wondering by decreasing the~read shoulder rigidity, the upper sidewall part (k) is provided with a narrow circumferential groove (g). This groove can not prevent lateral skid on the snowy/icy roads.
In Fig.8(B), to decrease the tread shoulder rigidity, the number of axial sipes (s) are increased. In this case, uneven wear and tear-off are increased, and lateral skid can not prevented.
As shown in Fig.8(C), Japanese Patent Publication (KOKAI) No 56-21905 discloses a tire having shoulder blocks (a) provided with two axial sipes ~s) extending continuously across khe whole axial width of the block, and one narrow groove (g) extending continuously across the whole circumferential length of the block. In this case, the tread elements adjacent to the tread edge (e) are liable to be torn off, and uneven wear and lateral skid are not fully prevented.
.
.
-SA---` 2~7~7~
In Figs.1-4, pneumatic tire 1 has a tread portion 12, a pair of axially spaced bead por~ions 15, and a pair of sidewall portions 13 extending between the tread edges E and the bead portions 15.
The tire 1 comprises a pair of bead cores 16 each disposed in each of the bead portions 15, a toroidal carcass 17 extending between the bead portions, and a belt 19 disposed - -radially outside the carcass 17 and inside a rubber tread. . -\
\~
-~ 2~7~7~2 The carcass 17 comprises at least one ply of cords arranged radially at 70 to 90 degrees with respect to the tire equator C to provide a radial or semiradial carcass structure.
For the carcass cords, steel cords and organic fiber cords, e.g. nylon, polyester, rayon, aromatic polyamide and the like can be used.
- - The belt 19-in th-is embodiment comprises three plies of cords laid bias with respect to the tire equator C so that - each ply cross the other plies.
For the belt cords, steel cords and organic fiber cords, e.g. nylon, polyester, rayon, aromatic polyamide and the like can be used.
The above-mentioned tread portion 12 is provided between the tread edges E with a convex profile (F) having a single radius curvature having the center on the tire equatorial plane. The radius TR of the curvature is in the range of 450 to 800 mm.
In-order to form a so called square shoulder to provide resistance to lateral skid on the snowy/icy roads, the tread profile (F) intersects with a concave profile (W) of the buttress portion or sidewaIl upper portion at the tread edge E.
The intersecting angle is determined such that the angle of the tread e~ge E is 90 to 140 degrees.
The tread portion 12 is provided with a plurality o~
wide main circumferential grooves G1 and GM extending 2~797;~2 ,, continuously around the tire, which grooves include a pair of axially outermost grooves G1 each disposed on each side of the tire equator C and a central groove GM disposed on the tire equator C.
Further, between each axially outermost wide main circumferential groove Gl and each tread edge E, only two narrow circumferential grooves G3 and G4 extending around the tire are provided.
Therefore, by the three wide circumferential grooves G1, GM
and four narrow circumferential grooves G3, G4, the tread portion 12 is divided into eight axial parts.
The tread portion 12 is further provided with axial grooves. The axial grooves includes crown axial grooves GP extending from the central main circumferential groove GM to the adjacent outer main circumferential groove Gl and shoulder axial grooves G2 extending from the axially outermost main circumferential groove G1 to the adjacent tread edge E to cross the narrow circumferential grooves G3 and G4.
Therefore, the above-mentioned eight axial parts are c1rcumferentially d1vided by the axial grooves into eight rows of blocks:
two rows LC of central blocks BC, each between the central circumferential groove GM and each of the outermost circumferential grooves Gl;
two rows LI of inner shoulder blocks BI, each between each 21~7~712 of the axially outermost wide main circumferential grooves G1 and the adjacent axially inner narrow circumferential groove G3;
two rows LM of middle shoulder blocks BM, each between each of the axially inner narrow circumferential grooves G3 and the adjacent axially outer narrow circumferential groove G4;
and two rows LO of outer shoulder blocks BO, each between each of the axially outer narrow circumferential grooves C4 and the adjacent tread edge E.
Accordingly, a block type tread pattern is formed.
Incidentally, a -tread part between the two axially outermost wide main circumferential grooves is called tread crown, and a tread part between the axially outermost wide main circumferential groove and the tread edge is called tread shoulder.
In this embodiment, the axial grooves GZ and GP have the same groove depth as the maximum depth DO of the wide main circumferential grooves Gl and GM.
However, the depths of the axial grooves can be differed from that of the wide main circumferential grooves.
Further, the depth of the axial grooves GP can be differed from that of the axial grooves G2. For example, the axially inner axial grooves are formed to be shallower than the axially outer axial grooves so that the blocks becomes a continuous rib in the middle of the tread wear life.
Furthermore, the depth of the axial grooves GP may be zero, 2~7~7~2 , that is, omitted.
The axial distance of the axially outermost wide main circumferential groove &1 from the tire equator C is 0.2 to 0.3 times the tread width TW which is defined as the axial distance between the tread edges E and E.
The narrow circumferential grooves G3 and G4 are formed in a straight configuration in this example, but the grooves can be formed in a zigzag configuration, a wavy configuration and the like.
The narrow circumf'erential grooves G3 and G4 are formed within a range M between points P and Q.
Here, the point P is located axially inward of the tread edge E by an axial distance W3 of 3 to 6 mm, and the point Q is located axially inward of the point P and at an axial distance W2 being 0.04 to 0.1 times the tread width TW from the tread edge E, which mean that the distance from the tread edge E to the axially outer narrow circumferential groove G4 is 3 to 6 mm, and the distance from the tread edge E to the inner shoulder block BI is 0.04 to 0.1 times the tread width TW.
Preferably, each narrow circumferential groove G3, G4 has a width WG in the range of 2.0 to 4.5 mm, and a depth D1 in the range of 0.3 to 1.2 times the maximum depth DO of the axially outermost circumferential groove Gl.
Therefore, the narrow circumferential grooves increase the road grip in the axial direction of the tire by the _ g .
~ .
. .
:
2~797~
increased edges and thereby improving resistance to lateral skid.
By forming only two narrow circumferential grooves in the specific range M, the rigidity of the blocks BO and B~ is decreased to prevent wanderin~ of the vehicle, but an excessive decrease is avoided, and loss of steering stability during straight running and cornering can be avoided.
If the number of the narrow circumferential grooves in more than two, steering stability is disturbed.
If the groove depth Dl is less than 0.3 times DO, the rigidity of the tread shoulder blocks BM and BO increases and the resistance to lateral skid can not be improved. If Dl is more than 1.2 times DO, lateral skid and uneven wear are liable to occur, and the steering stability is deteriorated.
If the groove width WG is less than 2.0 mm, the resistance to lateral skid can not effectively improved.
If ~he width is more than 4.5 mm, the shoulder blocks BM and BO become narrow to decrease the rigidity and lateral skid and uneven wear are caused.
Further, as shown in Fig.4, the center line of each narrow circumferential groove G3, G4 is inclined at an angle within +5 degrees with respect to the normal direction N to the tread profile F.
Preferably, the angle is zero, that is, in parallel with the normal direction so as to maximize the resistance to lateral .... .... .
207~7~
skid.
Each of the inner shoulder blocks BI is provided with at most five circumferentially spaced sipes S, in this embodiment three sipes SM and SE, extending between the axially outermost circumferential groove G1 and the axially inner narrow circumferential groove G3.
The width WS of the sipes S (SE and SM) is in the range of 0.3 to 1.5 mm.
Each of the sipes SM and SE has open ends opened at the circumferential grooves G1 and G3.
The sipe SM located in the circumferential center of the bloc~ ~I extends straight in the axial direction of the tire and is discontinuous in the middle thereof.
Preferably, the length of the discontinued portion 22 is 1.0 to Z.O times the width WS of the sipe.
The sipe SE located on each side of the central sipe SM
extends continuously and zigzag as shown in Fig.1 so as to form three axial parts:
an axially inner part extending in parallel with the axial direction;
an axially outer part extending in parallel with the axial direction and shifeed towards the central sipe SM than the inner part; and a middle part extending obliquely between the axially inner end of the axially outer part the axially outer end of the axially inner part.
The depth DZ of the sipes S (SE and SM~ is 0.5 to 1.0 7~
times the depth D1 of the axially inner narrow circumferential groove G2.
In this embodiment, the depth of the sipe SE is varied such that the sipe SE provided at the a~ially outer and inner ends with shallower portions 23.
The circumferential distance or spacing (L) between the circumferentially adjacent sipes is set in the range from 8 mm to 16 mm.
As explained above, a plurality of sipes are disposed in each of the inner shoulder blocks BI, but no sipe is disposed in the middle shoulder blocks BM and the outer shoulder blocks BO to maintain the rigidity thereof.
If the number of the sipes in one block BI is more than five, and if the sipe spacings ~L) are less than 8 mm, the inner shoulder block BI decreases in rigidity and uneven wear is liable to occur, and further cracks are liable to start from the s1pe bottoms.
On the other hand, if no sipe is formed, and if the sipe spacings are more than 16 mm, the rigidity of the inner shoulder blocks B1 increases and lateral skid is liable to occur.
The circumferential grooves G3 and G4 are provided with shallow portions or discontinued portions so that the adJacent shoulder blocks support each other.
In the circumferential grooves G3 and G4 in this embodiment, each circumferential groove part between the adjacent axial grooves G2 extends continuously straight and has ends opened at the groove sidewall of the axial grooves G2.
Further, each circumferential groove part of the outer groove G4 is provided with a shallow portions 20 in the middle of the length so that the adjacent narrow shoulder blocks BM and B0 support each other.
In the case that the depth of the narrow circumferential groove is varied, the depth is preferably restricted within the above men~ioned limit therefor.
However, if the Iength of the shallow portion 20 is less than 30% of the whole, the depth may be decreased to 50 % of the lower limit.
Fig.5(A) shows another example of the narrow circumferential groove G3, G4, which has a widened p~rtion (WL) between the adjacent axial grooves G2 and G2. This portion is not more than 20% in length.
Fig.5(B) shows stlll another example which has a wavy configuration.
Fig.5(C) shows still more another example which has a zigzag configuration, wherein the zigzag at the groove top is steeper than the groove bottom so that the zigzag angle becomes gentle and zigzag amplitude becomes small with the tread wear progresses.
Fig.6 shows another embodiment of the present invention, in which the narrow circumferential grooves G3 and G4 and the sipes SM and SE are modified.
In this embodiment, the axially inner narrow circumferential 2~7~7~2 groove G3 has discontinued portions 22 one between the central straight sipe SM and each zig~ag sipe S~.
The a~ially outer narrow circumferential groove G4 has shallow portions 20 at the opened ends on both side of each axial groove G2.
The central straight sipe SM extends continuously from the wide main circumferential groove Gl to the axially inner narrow circumferential groove G3, and accordingly, both the ends are opened at the grooves Gl and G3.
The zigzag sipe SE extends from the axially inner narrow circumferential groove G3, but the axially inner end is termin~ted within the block ~I near the main circumferential groove G1. Therefore, the sipe SE is discontinuous.
WORKING EXAMPLE
Test tires of size 1l.00R20 14PR having the tread pattern shown in Fig.1 and similar patterns and the tire structure shown in Fig.Z
were prepared and the following tests were made. The tire specifications and test results are given in Table 1. The test conditions are as follows.
A) Camber Thrust Test Using a drum, the camber thrust was measured under a camber angle of 6 degrees, a pressure of 7.25 Kgf/sq.cm and a tire load of 2,~40 kg. The larger plus value is better.
B) Self Alignment Effort Test Using a Z-D wheel type truck, the self alignment effort was evaluated by a skilled test driver. The results are - lg -7 ~ ~
indicated by an index based on that Example tire 3 is 100.
The larger the value, the better the result.
C) Tear-off Test By rubbing the tire sidewall against edging stone, the resis~ance to tear-off was evaluated. The results are indicated by an index based on that Example tire 3 is 100.
The larger the value, the better the resistance.
D) Shoulder Wear Test Running a test vehicle on a 100% paved road at an average speed of 80 km/Hr for 60,000 km, the amount of tread wear was measured.
In Table 1, the reciprocal number of the wear amount is indicated as the wear resistance by using an index based on that Example tire 3 is 100. The larger the value, the better the resistance to shoulder wear.
E) Snow Performance Test A braking test and a hill climb test were made on icebound test courses. The results are indicated by an index based on that Example tire 3 is 100. The larger the value, the better the snow performance.
It was confirmed frorn the test results that in comparison with the reference tires the working example tires had a large camber trust and a good self alignment effort and were improved in wandering, lateral skid, .
tear-off resistance shoulder wear resistance and steering stability on the snowy roads.
It was also confirmed from the graph shown in Fig.7(A) that 2~797~
the working example tire 3 was superior in lateral skid performance to the re~erence tires 1 and 2.
`: ;
:
:
:::: : ~
- 16 - .
2 ~ 7 ~ 2 t t t t I ~o N I17 N ! N ~0 ! -- I c + 0 0 0 0 t to + t ~ t t ~ ~ e ~ ~ NN O o I ~ N
~ ~ I ~ C O O ?~ ~_ N ~0 . ~ N U U 1 0 o ~ V ~o 0 0 0 U~ I
t, t ~ ~ t t t t N ~ ~ ~ N 11 o O N N-O O 1 0 0-- ~ ~q ~ O I O o 0 O I
t ,t - ~o 'S ~ ~ N e e ~o ~o ~ ~- o o, N N ~O O ~ , O I ~ O ID U~ O ~ 3 ~ ~ C 1~N I -- N-- I U -- I ~
t tD t t t t T t ~
j N I ,o o o O I~0 O ~ '1 i OI I ! ~ 0 N c j 0 U~
g~ o~ -oo-~ ol------~-! ~ i ~ Q o ! 10 N ~ N o 51 o _ _ N N ! -- I -- ! o ~ ~
t t + + ----------------------------~ t ---~ t ~~ ~~ t ~~ ~~ ~~~~ ~~~~ t ~
j 111 j ~ C U~ j _ N ~0 I N e c ~ ~ o o I ~ u~ -- I o--~ c I u~ O o oO oO j c r ~ _ + + + + + I I O ~ ~
~ X ! ~ C It~ v~;~ ! _ N ~0 ! N _ c c N N N N ! ~ I ~J o d ! ~ Q Q Q 07 ~
j D o oO ~i N O 2 N ~ N e c ~ ~ ~ ~ o o i ~ , . i 0 0 a o i 0 O O U~ O j ~ D 11 ---~ ---------------------- t -------------- I ---- . t t t E E E j E fi E ~ ~ E fi 0 I E E E j 8 j yl j E E
N* j 2 ~Ç a j ' U j -- -- ____ 1 ~ 3 C~ 3C 1 U) _______ 1~ ---_--__1 ", N
,~ ~ __ ~ _ _ _ _ _ _ _ _ ~ _ __ ~ _ _ _ _ _ _ __ __ _ __ '' ' ' `' ,
The present invention relates to a pneumatic tire having an improved tread pattern and squared shoulders, in which uneven tread wear is reduced and at the same time lateral skid and wandering are prevented to improve running performance on the snowy roads.
Recently, in order to prevent dust pollution, studless t-ires for used on snowy and-lcy-roads are going to be brought into greater use for heavy duty vehicle e.g.
truck and bus, instead of spike tires.
In the studless tires, block tread patterns are widely used to obtain a large traction and a large braking force.
In general, in order to improve traction and braking force, the tread blocks are provided with axial sipes so as to divide each block into comparatively small independent tread elements As the resultant small tread elements are easily moved during running, uneven wear is liable to occur, and the elements are liable to be torn o~f.
On the other hand, on the snowy roads, squared shoulders can provide a great lateral road grip than sipes.
However, such squared shoulders are liable to cause wondering of the vehicle during running on the well-paved roads but having shallow ruts.
To reduce wondering by decreasing the tread shoulder rigidity, the upper sidewall part is provided with a narrow circumferential groove This , ~ ~
~ 2~797-~2 groove can not prevent lateral skid on the snowy/icy roads.
To decrease the tread shoulder rigidity, the number of axial sipes are increased. In this case, ~-uneven wear and tear-off are increased, and lateral skid can not prevented. -Japanese Patent Publicatlon (KOKAI) No 56-21gO5 discloses a tire having shoulder blocks provided with two axia~~sipes - lextendlng continuously -across the whole axial width of the block-, and one narrow groove extending continuously~across the whole circumferential length of the block. In this case, the tread elements adjacent to the tread edge are liable to be torn off, and uneven wear and lateral skid are not fully prevented.
It is therefore, an object of the present invention to provide a pneumatic tlre having squared shoulders, in which by using a discontinuous sipe or narrow groove and then speciflcally defining the position, si2e, number and the like, lateral skid on the snowy roads and wondering on the well-paved roads are reduced without sacrificing a resistance to uneven wear and a resistance to tear-off.
Accordlng to one aspect of the present lnvention, a pneumatic tire comprising, a tread portion having a pair o-f tread edges, and a buttress portion e~tending radially inwardly from each of the tread edges forming a radially outer part of each tire sidewall, , .
' 2~7~7~2 the tread portion provided with an axially outermost wide main circumferential groove extending continuously in the ~ire circumferential direction and located on each side of the tire equator at a distance of 0.2 to 0.3 times the tread width from the tire equator, - two narrow circumferential grooves extending in the tire circumferential direction and located between the axially outermost wide main circumferential groove and the tread edge the two narrow circumferential grooves located within a tread edge region defined between an axially outer position spaced apart from the tread edge by a distance of 3 to 6 mm and an axially inner position spaced apart from the tread edge by a distance of 0.0~ to 0.1 times the tread width and circumferentially spaced axial grooves extending from the axially outermost wide main circumferential groove to the tread edge thereby forming circumferentially divided three rows of blocks in each tread shoulder portion the three rows of blocks being an axially inner row of inner shoulder blocks between the axially outermost wide main circumferential groove and the axially inner narrow circumferential groove a middle row o~ middle shoulder blocks 2~797~,~
between the two narrow circumferential grooves and an axially outer row of outer shoulder blocks between the axially outer narrow circumferential groove and the tread edge ~ .;
the tread portion provided with a convex profile, the :~
convex profile extending from one tread edge to the other - tread edge and having a radius of curvature -~of 45-O to -800 mm, the buttress portion provided with a concave profile intersecting with the convex profile of the tread portion at the tread edge to form a squared or angled tire shoulder, each of` the inner shoulder blocks provided with axial sipes the axial sipes including a discontinuous axial sipe extending discontinuously in the tire axial direction between the ~axially outermost wide main circumferential groove and the axially inner narrow circumferential groove and a continuous axial sipe extending continuously from the axially outermost wide main circumferential groove to the axially inner narrow circumferential groove~ , the number of the axial sipes in each of the inner shoulder blocks being not more than five, and the space between the axial sipes being 8 to 16 mm.
- - , 2~7~7~
.
In the accompanying drawings:
Fig.l is a developed plan view showing the tread portion of a truck/bus tire according to the present invention;
: .. . . . .. .
Fig.2 is a cross sectional view taken along the line X-X of Fig.l;
- ~ Fig;3 is a enlarged perspective view showing a tread shoulder region thereof;
Fig.4 is a- enlarged cross sec.tional view showing the narrow circumferential grooves;
Figs.5(A)-(C) are plan views showing other examples of the narrow circumferential groove;
Fig.6 is a perspective view of the tread shoulder region of another embodiment of the present invention; and Fig.7(A) is a graph showing relationship between camber thrust and camber angle and Fig.7~) is a diagram e~plaining the camber thrust and camber angle;
Figs.8(A)-(C) are perspective views showing prior art.
Before describing various embodiments of the invention, a description of the prior art shown in Figs 8(A)-(c) will be given.
: ~ :
In general, in order to improve traction and braking-force, the tread blocks (a) are provided with axial sipes (s) so as to divide each block into comparatively small independent tread elements, for example as shown in Figs.8(A)-(C).
, . .
, 2~7~7~ 2 .
As the resultant small tread elements are easily moved during running, uneven wear is liable to occur? and the elements are liable to be torn off.
On the other hand, on the snowy roads, squared shoulders can provide a great lateral road grip than sipes.
However, such squared shoulders are liable t:o cause wondering of- khe vehicle during running on the well-paved roads but having shallow ruts. - ~ -In Fig.8(A), to reduce wondering by decreasing the~read shoulder rigidity, the upper sidewall part (k) is provided with a narrow circumferential groove (g). This groove can not prevent lateral skid on the snowy/icy roads.
In Fig.8(B), to decrease the tread shoulder rigidity, the number of axial sipes (s) are increased. In this case, uneven wear and tear-off are increased, and lateral skid can not prevented.
As shown in Fig.8(C), Japanese Patent Publication (KOKAI) No 56-21905 discloses a tire having shoulder blocks (a) provided with two axial sipes ~s) extending continuously across khe whole axial width of the block, and one narrow groove (g) extending continuously across the whole circumferential length of the block. In this case, the tread elements adjacent to the tread edge (e) are liable to be torn off, and uneven wear and lateral skid are not fully prevented.
.
.
-SA---` 2~7~7~
In Figs.1-4, pneumatic tire 1 has a tread portion 12, a pair of axially spaced bead por~ions 15, and a pair of sidewall portions 13 extending between the tread edges E and the bead portions 15.
The tire 1 comprises a pair of bead cores 16 each disposed in each of the bead portions 15, a toroidal carcass 17 extending between the bead portions, and a belt 19 disposed - -radially outside the carcass 17 and inside a rubber tread. . -\
\~
-~ 2~7~7~2 The carcass 17 comprises at least one ply of cords arranged radially at 70 to 90 degrees with respect to the tire equator C to provide a radial or semiradial carcass structure.
For the carcass cords, steel cords and organic fiber cords, e.g. nylon, polyester, rayon, aromatic polyamide and the like can be used.
- - The belt 19-in th-is embodiment comprises three plies of cords laid bias with respect to the tire equator C so that - each ply cross the other plies.
For the belt cords, steel cords and organic fiber cords, e.g. nylon, polyester, rayon, aromatic polyamide and the like can be used.
The above-mentioned tread portion 12 is provided between the tread edges E with a convex profile (F) having a single radius curvature having the center on the tire equatorial plane. The radius TR of the curvature is in the range of 450 to 800 mm.
In-order to form a so called square shoulder to provide resistance to lateral skid on the snowy/icy roads, the tread profile (F) intersects with a concave profile (W) of the buttress portion or sidewaIl upper portion at the tread edge E.
The intersecting angle is determined such that the angle of the tread e~ge E is 90 to 140 degrees.
The tread portion 12 is provided with a plurality o~
wide main circumferential grooves G1 and GM extending 2~797;~2 ,, continuously around the tire, which grooves include a pair of axially outermost grooves G1 each disposed on each side of the tire equator C and a central groove GM disposed on the tire equator C.
Further, between each axially outermost wide main circumferential groove Gl and each tread edge E, only two narrow circumferential grooves G3 and G4 extending around the tire are provided.
Therefore, by the three wide circumferential grooves G1, GM
and four narrow circumferential grooves G3, G4, the tread portion 12 is divided into eight axial parts.
The tread portion 12 is further provided with axial grooves. The axial grooves includes crown axial grooves GP extending from the central main circumferential groove GM to the adjacent outer main circumferential groove Gl and shoulder axial grooves G2 extending from the axially outermost main circumferential groove G1 to the adjacent tread edge E to cross the narrow circumferential grooves G3 and G4.
Therefore, the above-mentioned eight axial parts are c1rcumferentially d1vided by the axial grooves into eight rows of blocks:
two rows LC of central blocks BC, each between the central circumferential groove GM and each of the outermost circumferential grooves Gl;
two rows LI of inner shoulder blocks BI, each between each 21~7~712 of the axially outermost wide main circumferential grooves G1 and the adjacent axially inner narrow circumferential groove G3;
two rows LM of middle shoulder blocks BM, each between each of the axially inner narrow circumferential grooves G3 and the adjacent axially outer narrow circumferential groove G4;
and two rows LO of outer shoulder blocks BO, each between each of the axially outer narrow circumferential grooves C4 and the adjacent tread edge E.
Accordingly, a block type tread pattern is formed.
Incidentally, a -tread part between the two axially outermost wide main circumferential grooves is called tread crown, and a tread part between the axially outermost wide main circumferential groove and the tread edge is called tread shoulder.
In this embodiment, the axial grooves GZ and GP have the same groove depth as the maximum depth DO of the wide main circumferential grooves Gl and GM.
However, the depths of the axial grooves can be differed from that of the wide main circumferential grooves.
Further, the depth of the axial grooves GP can be differed from that of the axial grooves G2. For example, the axially inner axial grooves are formed to be shallower than the axially outer axial grooves so that the blocks becomes a continuous rib in the middle of the tread wear life.
Furthermore, the depth of the axial grooves GP may be zero, 2~7~7~2 , that is, omitted.
The axial distance of the axially outermost wide main circumferential groove &1 from the tire equator C is 0.2 to 0.3 times the tread width TW which is defined as the axial distance between the tread edges E and E.
The narrow circumferential grooves G3 and G4 are formed in a straight configuration in this example, but the grooves can be formed in a zigzag configuration, a wavy configuration and the like.
The narrow circumf'erential grooves G3 and G4 are formed within a range M between points P and Q.
Here, the point P is located axially inward of the tread edge E by an axial distance W3 of 3 to 6 mm, and the point Q is located axially inward of the point P and at an axial distance W2 being 0.04 to 0.1 times the tread width TW from the tread edge E, which mean that the distance from the tread edge E to the axially outer narrow circumferential groove G4 is 3 to 6 mm, and the distance from the tread edge E to the inner shoulder block BI is 0.04 to 0.1 times the tread width TW.
Preferably, each narrow circumferential groove G3, G4 has a width WG in the range of 2.0 to 4.5 mm, and a depth D1 in the range of 0.3 to 1.2 times the maximum depth DO of the axially outermost circumferential groove Gl.
Therefore, the narrow circumferential grooves increase the road grip in the axial direction of the tire by the _ g .
~ .
. .
:
2~797~
increased edges and thereby improving resistance to lateral skid.
By forming only two narrow circumferential grooves in the specific range M, the rigidity of the blocks BO and B~ is decreased to prevent wanderin~ of the vehicle, but an excessive decrease is avoided, and loss of steering stability during straight running and cornering can be avoided.
If the number of the narrow circumferential grooves in more than two, steering stability is disturbed.
If the groove depth Dl is less than 0.3 times DO, the rigidity of the tread shoulder blocks BM and BO increases and the resistance to lateral skid can not be improved. If Dl is more than 1.2 times DO, lateral skid and uneven wear are liable to occur, and the steering stability is deteriorated.
If the groove width WG is less than 2.0 mm, the resistance to lateral skid can not effectively improved.
If ~he width is more than 4.5 mm, the shoulder blocks BM and BO become narrow to decrease the rigidity and lateral skid and uneven wear are caused.
Further, as shown in Fig.4, the center line of each narrow circumferential groove G3, G4 is inclined at an angle within +5 degrees with respect to the normal direction N to the tread profile F.
Preferably, the angle is zero, that is, in parallel with the normal direction so as to maximize the resistance to lateral .... .... .
207~7~
skid.
Each of the inner shoulder blocks BI is provided with at most five circumferentially spaced sipes S, in this embodiment three sipes SM and SE, extending between the axially outermost circumferential groove G1 and the axially inner narrow circumferential groove G3.
The width WS of the sipes S (SE and SM) is in the range of 0.3 to 1.5 mm.
Each of the sipes SM and SE has open ends opened at the circumferential grooves G1 and G3.
The sipe SM located in the circumferential center of the bloc~ ~I extends straight in the axial direction of the tire and is discontinuous in the middle thereof.
Preferably, the length of the discontinued portion 22 is 1.0 to Z.O times the width WS of the sipe.
The sipe SE located on each side of the central sipe SM
extends continuously and zigzag as shown in Fig.1 so as to form three axial parts:
an axially inner part extending in parallel with the axial direction;
an axially outer part extending in parallel with the axial direction and shifeed towards the central sipe SM than the inner part; and a middle part extending obliquely between the axially inner end of the axially outer part the axially outer end of the axially inner part.
The depth DZ of the sipes S (SE and SM~ is 0.5 to 1.0 7~
times the depth D1 of the axially inner narrow circumferential groove G2.
In this embodiment, the depth of the sipe SE is varied such that the sipe SE provided at the a~ially outer and inner ends with shallower portions 23.
The circumferential distance or spacing (L) between the circumferentially adjacent sipes is set in the range from 8 mm to 16 mm.
As explained above, a plurality of sipes are disposed in each of the inner shoulder blocks BI, but no sipe is disposed in the middle shoulder blocks BM and the outer shoulder blocks BO to maintain the rigidity thereof.
If the number of the sipes in one block BI is more than five, and if the sipe spacings ~L) are less than 8 mm, the inner shoulder block BI decreases in rigidity and uneven wear is liable to occur, and further cracks are liable to start from the s1pe bottoms.
On the other hand, if no sipe is formed, and if the sipe spacings are more than 16 mm, the rigidity of the inner shoulder blocks B1 increases and lateral skid is liable to occur.
The circumferential grooves G3 and G4 are provided with shallow portions or discontinued portions so that the adJacent shoulder blocks support each other.
In the circumferential grooves G3 and G4 in this embodiment, each circumferential groove part between the adjacent axial grooves G2 extends continuously straight and has ends opened at the groove sidewall of the axial grooves G2.
Further, each circumferential groove part of the outer groove G4 is provided with a shallow portions 20 in the middle of the length so that the adjacent narrow shoulder blocks BM and B0 support each other.
In the case that the depth of the narrow circumferential groove is varied, the depth is preferably restricted within the above men~ioned limit therefor.
However, if the Iength of the shallow portion 20 is less than 30% of the whole, the depth may be decreased to 50 % of the lower limit.
Fig.5(A) shows another example of the narrow circumferential groove G3, G4, which has a widened p~rtion (WL) between the adjacent axial grooves G2 and G2. This portion is not more than 20% in length.
Fig.5(B) shows stlll another example which has a wavy configuration.
Fig.5(C) shows still more another example which has a zigzag configuration, wherein the zigzag at the groove top is steeper than the groove bottom so that the zigzag angle becomes gentle and zigzag amplitude becomes small with the tread wear progresses.
Fig.6 shows another embodiment of the present invention, in which the narrow circumferential grooves G3 and G4 and the sipes SM and SE are modified.
In this embodiment, the axially inner narrow circumferential 2~7~7~2 groove G3 has discontinued portions 22 one between the central straight sipe SM and each zig~ag sipe S~.
The a~ially outer narrow circumferential groove G4 has shallow portions 20 at the opened ends on both side of each axial groove G2.
The central straight sipe SM extends continuously from the wide main circumferential groove Gl to the axially inner narrow circumferential groove G3, and accordingly, both the ends are opened at the grooves Gl and G3.
The zigzag sipe SE extends from the axially inner narrow circumferential groove G3, but the axially inner end is termin~ted within the block ~I near the main circumferential groove G1. Therefore, the sipe SE is discontinuous.
WORKING EXAMPLE
Test tires of size 1l.00R20 14PR having the tread pattern shown in Fig.1 and similar patterns and the tire structure shown in Fig.Z
were prepared and the following tests were made. The tire specifications and test results are given in Table 1. The test conditions are as follows.
A) Camber Thrust Test Using a drum, the camber thrust was measured under a camber angle of 6 degrees, a pressure of 7.25 Kgf/sq.cm and a tire load of 2,~40 kg. The larger plus value is better.
B) Self Alignment Effort Test Using a Z-D wheel type truck, the self alignment effort was evaluated by a skilled test driver. The results are - lg -7 ~ ~
indicated by an index based on that Example tire 3 is 100.
The larger the value, the better the result.
C) Tear-off Test By rubbing the tire sidewall against edging stone, the resis~ance to tear-off was evaluated. The results are indicated by an index based on that Example tire 3 is 100.
The larger the value, the better the resistance.
D) Shoulder Wear Test Running a test vehicle on a 100% paved road at an average speed of 80 km/Hr for 60,000 km, the amount of tread wear was measured.
In Table 1, the reciprocal number of the wear amount is indicated as the wear resistance by using an index based on that Example tire 3 is 100. The larger the value, the better the resistance to shoulder wear.
E) Snow Performance Test A braking test and a hill climb test were made on icebound test courses. The results are indicated by an index based on that Example tire 3 is 100. The larger the value, the better the snow performance.
It was confirmed frorn the test results that in comparison with the reference tires the working example tires had a large camber trust and a good self alignment effort and were improved in wandering, lateral skid, .
tear-off resistance shoulder wear resistance and steering stability on the snowy roads.
It was also confirmed from the graph shown in Fig.7(A) that 2~797~
the working example tire 3 was superior in lateral skid performance to the re~erence tires 1 and 2.
`: ;
:
:
:::: : ~
- 16 - .
2 ~ 7 ~ 2 t t t t I ~o N I17 N ! N ~0 ! -- I c + 0 0 0 0 t to + t ~ t t ~ ~ e ~ ~ NN O o I ~ N
~ ~ I ~ C O O ?~ ~_ N ~0 . ~ N U U 1 0 o ~ V ~o 0 0 0 U~ I
t, t ~ ~ t t t t N ~ ~ ~ N 11 o O N N-O O 1 0 0-- ~ ~q ~ O I O o 0 O I
t ,t - ~o 'S ~ ~ N e e ~o ~o ~ ~- o o, N N ~O O ~ , O I ~ O ID U~ O ~ 3 ~ ~ C 1~N I -- N-- I U -- I ~
t tD t t t t T t ~
j N I ,o o o O I~0 O ~ '1 i OI I ! ~ 0 N c j 0 U~
g~ o~ -oo-~ ol------~-! ~ i ~ Q o ! 10 N ~ N o 51 o _ _ N N ! -- I -- ! o ~ ~
t t + + ----------------------------~ t ---~ t ~~ ~~ t ~~ ~~ ~~~~ ~~~~ t ~
j 111 j ~ C U~ j _ N ~0 I N e c ~ ~ o o I ~ u~ -- I o--~ c I u~ O o oO oO j c r ~ _ + + + + + I I O ~ ~
~ X ! ~ C It~ v~;~ ! _ N ~0 ! N _ c c N N N N ! ~ I ~J o d ! ~ Q Q Q 07 ~
j D o oO ~i N O 2 N ~ N e c ~ ~ ~ ~ o o i ~ , . i 0 0 a o i 0 O O U~ O j ~ D 11 ---~ ---------------------- t -------------- I ---- . t t t E E E j E fi E ~ ~ E fi 0 I E E E j 8 j yl j E E
N* j 2 ~Ç a j ' U j -- -- ____ 1 ~ 3 C~ 3C 1 U) _______ 1~ ---_--__1 ", N
,~ ~ __ ~ _ _ _ _ _ _ _ _ ~ _ __ ~ _ _ _ _ _ _ __ __ _ __ '' ' ' `' ,
Claims (7)
1. A pneumatic tire comprising a tread portion having a pair of tread edges, a buttress portion extending radially inwardly from each of said tread edges forming a radially outer part of each tire sidewall, said tread portion provided with .
an axially outermost wide main circumferential groove extending continuously in the tire circumferential direction and located on each side of the tire equator at a distance of 0.2 to 0.3 times the tread width from the tire equator, two narrow circumferential grooves extending in the tire circumferential direction and located between said axially outermost wide main circumferential groove and the tread edge said two narrow circumferential grooves located within a tread edge region defined between an axially outer position spaced apart from the tread edge by a distance of 3 to 6 mm and an axially inner position spaced apart from the tread edge by a distance of 0.04 to 0.1 times the tread width , and circumferentially spaced axial grooves extending from said axially outermost wide main circumferential groove to the tread edge thereby forming circumferentially divided three rows of blocks in each tread shoulder portion said three rows of blocks being an axially inner row of inner shoulder blocks between the axially outermost wide main circumferential groove and the axially inner narrow circumferential groove a middle row of middle shoulder blocks between said two narrow circumferential grooves and an axially outer row of outer shoulder blocks between the axially outer narrow circumferential groove and the tread edge said tread portion provided with a convex profile, said convex profile extending from one tread edge to the other tread edge and having a radius of curvature of 450 to 800 mm, said buttress portion provided with a concave profile intersecting with the convex profile of said tread portion at the tread edge to form a squared or angled tire shoulder, each of the inner shoulder blocks provided with axial sipes, said axial sipes including a discontinuous axial sipe extending discontinuously in the tire axial direction between the axially outermost wide main circumferential groove and the axially inner narrow circumferential groove , and a continuous axial sipe extending continuously from the axially outermost wide main circumferential groove to the axially inner narrow circumferential groove , the number of said axial sipes in each of the inner shoulder blocks being not more than five, and the space between the axial sipes being 8 to 18 mm.
an axially outermost wide main circumferential groove extending continuously in the tire circumferential direction and located on each side of the tire equator at a distance of 0.2 to 0.3 times the tread width from the tire equator, two narrow circumferential grooves extending in the tire circumferential direction and located between said axially outermost wide main circumferential groove and the tread edge said two narrow circumferential grooves located within a tread edge region defined between an axially outer position spaced apart from the tread edge by a distance of 3 to 6 mm and an axially inner position spaced apart from the tread edge by a distance of 0.04 to 0.1 times the tread width , and circumferentially spaced axial grooves extending from said axially outermost wide main circumferential groove to the tread edge thereby forming circumferentially divided three rows of blocks in each tread shoulder portion said three rows of blocks being an axially inner row of inner shoulder blocks between the axially outermost wide main circumferential groove and the axially inner narrow circumferential groove a middle row of middle shoulder blocks between said two narrow circumferential grooves and an axially outer row of outer shoulder blocks between the axially outer narrow circumferential groove and the tread edge said tread portion provided with a convex profile, said convex profile extending from one tread edge to the other tread edge and having a radius of curvature of 450 to 800 mm, said buttress portion provided with a concave profile intersecting with the convex profile of said tread portion at the tread edge to form a squared or angled tire shoulder, each of the inner shoulder blocks provided with axial sipes, said axial sipes including a discontinuous axial sipe extending discontinuously in the tire axial direction between the axially outermost wide main circumferential groove and the axially inner narrow circumferential groove , and a continuous axial sipe extending continuously from the axially outermost wide main circumferential groove to the axially inner narrow circumferential groove , the number of said axial sipes in each of the inner shoulder blocks being not more than five, and the space between the axial sipes being 8 to 18 mm.
2. The pneumatic tire according to claim 1, wherein each of said two narrow circumferential grooves has a depth of 0.3 to 1.20 times the groove depth of the axially outermost wide main circumferential groove and a width of 2.0 to 4.5 mm.
3. The pneumatic tire according to claim 1, wherein each of the inner shoulder blocks is provided with three axial sipes including a straight axial sipe and two zigzag axial sipes located one on each side of the straight axial sipe , each zigzag sipe composed of two axial portions and one oblique portion therebetween.
4. The pneumatic tire according to claim 3, wherein said straight axial sipe is discontinuous in the middle thereof, and said two zigzag sipes are continuous.
5. The pneumatic tire according to claim 3, wherein said straight axial sipe is continuous, and said two zigzag sipes are discontinuous at the axially inner end thereof.
6. The pneumatic tire according to claim 1, wherein the axially outer narrow circumferential groove provided between said axial grooves with at least one shallow portion .
7. The pneumatic tire according to claim 1, wherein the axially inner narrow circumferential groove provided between said axial grooves with at least one discontinued portion
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3296205A JPH05104912A (en) | 1991-10-15 | 1991-10-15 | Pneumatic tire |
| JP3-296205 | 1991-10-15 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2079712A1 true CA2079712A1 (en) | 1993-04-16 |
Family
ID=17830536
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002079712A Abandoned CA2079712A1 (en) | 1991-10-15 | 1992-10-02 | Pneumatic tire |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPH05104912A (en) |
| CA (1) | CA2079712A1 (en) |
| FI (1) | FI924612A (en) |
| NO (1) | NO177490C (en) |
| SE (1) | SE505191C2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6374884B2 (en) * | 1998-12-21 | 2002-04-23 | Sumitomo Rubber Industries, Ltd. | Heavy duty tire including narrow groove |
| CN103158442A (en) * | 2011-12-13 | 2013-06-19 | 风神轮胎股份有限公司 | Winter tire of truck and passenger car |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63265705A (en) * | 1987-04-23 | 1988-11-02 | Yokohama Rubber Co Ltd:The | Flat radial tire for small truck |
| JPH0295903A (en) * | 1988-10-03 | 1990-04-06 | Bridgestone Corp | Pneumatic tyre for heavy load |
| JP2755353B2 (en) * | 1989-12-15 | 1998-05-20 | 住友ゴム工業 株式会社 | Heavy duty tire |
-
1991
- 1991-10-15 JP JP3296205A patent/JPH05104912A/en active Pending
-
1992
- 1992-09-30 SE SE9202842A patent/SE505191C2/en not_active IP Right Cessation
- 1992-10-02 CA CA002079712A patent/CA2079712A1/en not_active Abandoned
- 1992-10-12 FI FI924612A patent/FI924612A/en unknown
- 1992-10-14 NO NO923980A patent/NO177490C/en unknown
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6374884B2 (en) * | 1998-12-21 | 2002-04-23 | Sumitomo Rubber Industries, Ltd. | Heavy duty tire including narrow groove |
| CN103158442A (en) * | 2011-12-13 | 2013-06-19 | 风神轮胎股份有限公司 | Winter tire of truck and passenger car |
Also Published As
| Publication number | Publication date |
|---|---|
| NO177490C (en) | 1995-09-27 |
| SE9202842L (en) | 1993-04-16 |
| NO923980L (en) | 1993-04-16 |
| FI924612A0 (en) | 1992-10-12 |
| NO177490B (en) | 1995-06-19 |
| FI924612A (en) | 1993-04-16 |
| SE505191C2 (en) | 1997-07-14 |
| NO923980D0 (en) | 1992-10-14 |
| SE9202842D0 (en) | 1992-09-30 |
| JPH05104912A (en) | 1993-04-27 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0841199B1 (en) | Pneumatic tyre | |
| US6003575A (en) | Pneumatic tire including sipes | |
| US6170546B1 (en) | Heavy duty pneumatic tire including variable width grooves and constant width grooves | |
| EP0844107A2 (en) | Pneumatic tyre | |
| US6192953B1 (en) | Heavy duty radial tire having tapered shoulder portions | |
| US7093630B2 (en) | Heavy duty radial tire | |
| JP3145762B2 (en) | Pneumatic tire | |
| US5360046A (en) | Heavy duty tire with reduced shoulder wear and improved wandering performance | |
| JP3206837B2 (en) | Pneumatic tire | |
| JP3337414B2 (en) | Radial tires for heavy loads | |
| US4957149A (en) | Pneumatic tire tread with plural overlapping narrow grooves in shoulder | |
| EP0093072A2 (en) | A pneumatic tire | |
| EP0965464B1 (en) | Heavy duty tyre | |
| JP3563468B2 (en) | Studless pneumatic tires for heavy loads | |
| JP2664116B2 (en) | Pneumatic tire | |
| JP3113343B2 (en) | Pneumatic tire | |
| CA2080328C (en) | Pneumatic tire | |
| CA2079712A1 (en) | Pneumatic tire | |
| CA2084741C (en) | Block pattern tire with optimized groove depth ratios, sipe depth and length ratios | |
| JP2547286B2 (en) | Pneumatic tire | |
| JP2892152B2 (en) | Pneumatic tire | |
| JP2809344B2 (en) | Radial tire | |
| JP2628949B2 (en) | Studless tires for motorcycles | |
| JPH06171319A (en) | Pneumatic tire | |
| JP2755353B2 (en) | Heavy duty tire |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |