CN106976362B - Pneumatic tire - Google Patents

Abstract

A kind of pneumatic tire that can improve dry ground performance and snowfield performance simultaneously is provided.Have: a pair of inside circumferential slot (21) is disposed in the two sides of the equatorial plane (CL) on tire width direction；A pair of outside circumferential slot (25) is disposed in the respective outside of a pair of inside circumferential slot (21) on tire width direction；Central translot (31), its both ends is connect with a pair of inside circumferential slot (21), and is had in the circumferential extensions (33) upwardly extended in tire week and the width direction extension (34) extended on tire width direction；Central block (11) is divided by central translot (31) and inner circumferential slot (21)；And bending part recess portion (40), the position of its bad angle side for being formed in bending part (32), and it is connect with circumferential extensions (33) and width direction extension (34), contact area ratio in middle section is 30% or more and 70% or less, the middle section is 10% region of the width on the tire width direction of central block (11) centered on the center of the central block (11) on tire width direction.

Description

Pneumatic tire

Technical field

The present invention relates to pneumatic tires.

Background technique

Pneumatic tire is formed with slot in tread surface mainly for ensuring drainage, still, if slot excessively if land portion Rigidity reduces, so that control stability and/or wear resistance reduce, therefore there is the arranging to slot in previous pneumatic tire Form is worked hard, and the technology of the raising of their opposite performance is thus sought.For example, the inflated wheel described in patent document 1 In tire, four circumferential slots extended along tire circumferential direction zigzag are arranged in arrangement on tire width direction, in four circumferential directions Two circumferential slots of the inside on tire width direction in slot are equipped with the translot for being formed as crankshaft shape each other, thus seek Ask the raising in the traction property and wear resistance on wetland road surface.

Existing technical literature

Patent document

Patent document 1: Japanese Unexamined Patent Publication 2006-111122 bulletin

Summary of the invention

Problems to be solved by the invention

Here, pneumatic tire grounding characteristics due to the weight of vehicle when driving change, especially, in unloaded cargo In the difference of the weight of the weight and cargo full load of state very big truck and/or car, the variation of the weight of adjoint vehicle Grounding characteristics are changed significantly.For example, in truck and/or car, in the vehicle that multiple wheels are installed in overlapping, without loading The contact area with road surface when state, that is, empty wagons of object, compared with when being mounted with the i.e. entrucking of state of cargo, in pneumatic tire Small, only middle section is nearby grounded.In this way, in the case where contact area is small, the tread surface of pneumatic tire and road surface it Between be easy to happen skidding, therefore skid in order to prevent, preferably the groove area ratio near reduction middle section, still, if reducing slot Area ratio is then reduced in the driving performance of snow road.

That is, pneumatic tire tyre surface formed slot other than drainage, be also to the driving performance in snow road Snowfield performance is contributed.But increasing can be passed through relative to the driving performance dry ground performance in dry road traveling Adjunction ground area improves performance, and snowfield performance then mainly improves snow column shearing force etc. by increasing groove area raising property Can, therefore dry ground performance and snowfield performance are the element of antinomy.Accordingly, it is difficult to improve dry ground performance and snowfield simultaneously Can, especially, with the loading condition of cargo independently, dry ground performance and snowfield are independently taken into account with empty wagons and/or entrucking It can be very difficult.

The present invention is made in view of above-mentioned, it is intended that dry ground performance and snow can be improved simultaneously by providing one kind The pneumatic tire of ground performance.

Technical teaching for solving the problem was

In order to solve the problem above-mentioned, achieve the goal, pneumatic tire of the invention is characterized in that having: a pair of inside Circumferential slot clips equatorial plane and is disposed in the two sides of the equatorial plane on tire width direction, and in tire Week upwardly extends；A pair of outside circumferential slot is disposed in the respective of a pair of inner circumferential slot on tire width direction Outside, and upwardly extended in tire week；Multiple center translots, both ends are connect with a pair of inner circumferential slot, and more Thus a position bending has in the circumferential extensions upwardly extended in tire week and the width side extended on tire width direction To extension；Central block, for the land portion marked off by the central translot and the inner circumferential slot；And bending part is recessed Portion is recessed and shape by the position of the bad angle side of the bending part of the central translot in the central block from tread surface At, and connect with the circumferential extensions and the width direction extension, the contact area ratio in middle section is 30% or more and 70% hereinafter, the middle section is centered on the center of the central block on tire width direction, institute State 10% region of the width on the tire width direction of central block.

In addition, the preferably described circumferential extensions is located in the middle section in above-mentioned pneumatic tire.

In addition, the preferably described bending part recess portion is formed by chamfering in above-mentioned pneumatic tire.

In addition, the preferably described bending part recess portion is formed as in above-mentioned pneumatic tire, it is connect with the circumferential extensions It is partially and with the part of width direction extension connection equal length.

In addition, the preferably described bending part recess portion is formed as, and the depth away from the tread surface exists in above-mentioned pneumatic tire In 20% or more of groove depth and 50% or less range of the center translot.

In addition, being preferably formed with central gap portion in the central block in above-mentioned pneumatic tire, which is set It is placed on the extended line of the width direction extension, and one end is connect with the bending part, the other end is in the central block Interior termination.

In addition, the preferably described central gap portion is formed as, along the width direction extension in above-mentioned pneumatic tire Formation direction direction the central block of the length on tire width direction width 10% or more and 20% or less In the range of.

In addition, the bending part recess portion and the central gap portion are preferably to be connected to jointly in above-mentioned pneumatic tire The bending part the bending part recess portion opening area A1 and the central gap portion opening area A2 relationship be 3 ≤(A2/A1)≤6。

In addition, in above-mentioned pneumatic tire, it is preferred that have: multiple intermediate translots, both ends and it is adjacent it is described in Side circumferential slot is connected with the external circumferential slot；Multiple tire shoulder translots are disposed in the tyre width side of the external circumferential slot Upward outside, one end are connect with the external circumferential slot；Intermediate mass, for by the inner circumferential slot, the external circumferential The land portion that slot and the intermediate translot mark off；And shoulder block, for by the external circumferential slot and the tire shoulder translot The land portion marked off is formed with central indentation portion in the intermediate mass, which is set to prolonging for the tire shoulder translot On long line, and one end is connect with the external circumferential slot, and the other end terminates in intermediate mass, is formed with tire in the shoulder block Shoulder notch section, the tire shoulder notch section are set on the extended line of the intermediate translot, and one end and the external circumferential slot connect It connects, the other end terminates in shoulder block.

In addition, the preferably described intermediate translot is formed as in above-mentioned pneumatic tire, it is circumferential to tyre width relative to tire The tilt angle in direction is in 75 ° or more and 105 ° or less of range.

In addition, in above-mentioned pneumatic tire, the intermediate translot and the tire shoulder translot be preferably, the intermediate translot Relative to the circumferential to tire relative to tire of the circumferential inclination angle alpha 1 to tire width direction of tire and the tire shoulder translot The relationship of the inclination angle alpha 2 of width direction be 0 °≤| α 2- α 1 |≤10 °.

In addition, the inner circumferential slot and the external circumferential slot are preferably the inside week in above-mentioned pneumatic tire Relationship to the groove width W2 of the groove width W1 and external circumferential slot of slot is 0.5≤(W2/W1)≤0.9.

In addition, the width on the tire width direction of the preferably described central block is tyre surface expansion in above-mentioned pneumatic tire 20% or more and 40% or less of width.

In addition, length L and tire width direction in above-mentioned pneumatic tire, in the tire circumferential direction of the preferably described central block On width W ratio be 0.9≤(L/W)≤1.1.

Additionally, it is preferred that the purposes of above-mentioned pneumatic tire is heavy duty pneumatic vehicle tire.

The effect of invention

Pneumatic tire of the invention can play while improve the effect of dry ground performance and snowfield performance.

Detailed description of the invention

Fig. 1 is the meridian cross-sectional view for indicating the major part of pneumatic tire of embodiment.

Fig. 2 is the A-A direction view of Fig. 1.

Fig. 3 is that the portion B of Fig. 2 schemes in detail.

Fig. 4 is the explanatory diagram of bending part spatial portion.

Fig. 5 is that the portion C of Fig. 2 schemes in detail.

Fig. 6 A is the chart for indicating the result of performance test of pneumatic tire.

Fig. 6 B is the chart for indicating the result of performance test of pneumatic tire.

Fig. 6 C is the chart for indicating the result of performance test of pneumatic tire.

Fig. 6 D is the chart for indicating the result of performance test of pneumatic tire.

Description of symbols

1 pneumatic tire

2 fetus faces

3 tread surfaces

4 shoulder portion

5 sidewalls

6 carcasses

7 belts

8 liner layers

10 lands portion

11 central blocks

12 intermediate mass

13 shoulder blocks

20 circumferential slots

21 inner circumferential slots

25 external circumferential slots

30 translots

31 central translots

32 bending parts

33 circumferential extensions

34 width direction extensions

35 intermediate translots

36 tire shoulder translots

40 bending part recess portions

42 bending part spatial portions

45 central gap portions

46 central indentation portions

47 tire shoulder notch sections

50 bead parts

CL equatorial plane

CA middle section

Specific embodiment

Hereinafter, being described in detail based on embodiment of the attached drawing to pneumatic tire of the invention.In addition, the present invention is simultaneously It is not limited to the embodiment.In addition, including that those skilled in the art can replace in the constituent element of following embodiments And the element or substantially the same element being readily apparent that.

In the following description, so-called tire width direction refers to the direction parallel with the rotary shaft of pneumatic tire, so-called Just refer to the direction on tire width direction towards equatorial plane, so-called tire width direction foreign side in tire width direction Refer on tire width direction towards the opposite direction in the direction of equatorial plane.In addition, so-called tire radially refers to and takes turns The direction of tire rotating shaft direct cross, so-called tire diameter inwardly just refers in tire axially towards to the direction of tire rotary shaft, so-called Tire diameter refers to outward in the direction that tire leaves radially from tire rotary shaft.In addition, so-called tire circumferentially refers to take turns The direction that tire rotary shaft pivots about.

Fig. 1 is the meridian cross-sectional view for indicating the major part of pneumatic tire of embodiment.Pneumatic tire 1 shown in FIG. 1 In the case where observation in meridian cross-sectional view, it is equipped with fetus face 2 in the part of the most outward side of tire radial direction, fetus face 2 Surface in the part that the vehicle (illustration omitted) for being mounted with the pneumatic tire 1 is contacted with road surface is when driving formed as tyre surface table Face 3.Multiple circumferential slots 20 upwardly extended in tire week are formed in tread surface 3, and are formed with multiple and circumferential slot 20 The translot 30 of intersection (referring to Fig. 2).In tread surface 3, multiple land portions 10 are marked off by the multiple circumferential slot 20 and translot 30.

The both ends of fetus face 2 on tire width direction are formed as shoulder portion 4, from shoulder portion 4 to tire radial direction inward side Scheduled position until, be equipped with sidewall 5.That is, sidewall 5 is disposed in two of the pneumatic tire 1 on tire width direction Two positions of side.

Moreover, bead part 50 is located at the tire radial direction inward side of each sidewall 5, bead part 50 is matched in the same manner as sidewall 5 Set on two positions of the two sides of equatorial plane CL.That is, equatorial plane CL of the bead part 50 on tire width direction Two sides are equipped with a pair.It is each provided with bead core 51 in a pair of bead portion 50, is set outward in the tire diameter of each bead core 51 There is bead filler (bead filler) 55.Bead core 51 is by circlewise forming the winding of the steel bead wire as steel wire.Edge Mouthful filler 55 is arranged in from the tire width direction end of aftermentioned carcass (carcass) 6 in the position of bead core 51 to wheel Tire width direction outward side is turned back and the rubber material in space that is formed.

Belt 7 is inwardly just equipped in the tire diameter of fetus face 2.Belt 7 is for example in 71,72,73,74 layers of quadriply belt beam Folded multi-ply construction is the multiple belt cords that will be made of the organic fibers material such as steel wire or polyester, staple fibre, nylon Covered with fiber-reinforced rubber and roll processing and constitute.In addition, banding 71,72,73,74 is configured to, the fibre as belt cord Dimension direction is mutually different relative to the belt cord that the inclination angle of tire circumferential direction defines and keeps the machine direction of belt cord mutual Cross layered (cross-ply) be laminated across, so-called construction.

It is continuously equipped in the side equatorial plane CL of the inside side of the tire diameter of the belt 7 and sidewall 5 by meridian Cord in wrap carcass 6.The carcass 6 has the monolayer constructions being made of one piece of carcass ply, or by multiple carcass plies The multi-ply construction constituted is laminated, ring-type sets up and constitutes wheel between the bead core 51 for the two sides being disposed on tire width direction The skeleton of tire.It is detailed to be, tyre bead of the carcass 6 from the side in a pair of bead portion 50 for the two sides being located on tire width direction Portion 50 be arranged to another party bead part 50, and in a manner of being packed in bead core 51 and bead filler 55 in bead part 50 along tire Core 51 is enclosed to tire width direction foreign side rollback.The carcass ply for the carcass 6 being arranged in this way uses the carcass being made of steel Line, that is, steel cord covers multiple steel cords with fiber-reinforced rubber and rolls processing and constitute.That is, carcass 6 using steel carcass material structure At.

In addition, carcass 6 inward side or the carcass 6, the private side in pneumatic tire 1 is formed with along carcass 6 Liner layer 8.

Fig. 2 is the A-A direction view of Fig. 1.As the circumferential slot 20 formed in tread surface 3, it is provided with a pair of inside circumferential direction Slot 21 and a pair of outside circumferential slot 25, the pair of inner circumferential slot 21 clip equatorial plane CL and are disposed in tire width direction On equatorial plane CL two sides, and upwardly extended in tire week, the pair of external circumferential slot 25 is in tyre width side It is disposed in the respective outside of a pair of inside circumferential slot 21 upwards, and is upwardly extended in tire week.That is, about inner circumferential slot 21, two inner circumferential slots 21 are disposed in the two sides of the equatorial plane CL on tire width direction, about external circumferential slot 25, Two external circumferential slots 25 clip two inner circumferential slots 21 on tire width direction and are disposed in two inner circumferential slots 21 Tire width direction on two sides.The inner circumferential slot 21 and the respective one side of external circumferential slot 25 are on tire width direction It is formed extended at both sides in tire circumferential direction on one side with amplitude.

In addition, the groove width of inner circumferential slot 21 is in the range of 6mm or more and 15mm or less, groove depth in 10mm or more and In the range of 18mm or less.In addition, the groove width of external circumferential slot 25 is in the range of 4mm or more and 12mm or less, groove depth is in 6mm Above and in the range of 18mm or less.In addition, about inner circumferential slot 21 and external circumferential slot 25, the groove width of inner circumferential slot 21 W1 (referring to Fig. 5) is bigger than the groove width W2 of external circumferential slot 25 (referring to Fig. 5).In more detail, about inner circumferential slot 21 and outside Side circumferential slot 25, the relationship of the groove width W2 of the groove width W1 and external circumferential slot 25 of inner circumferential slot 21 be 0.5≤(W2/W1)≤ 0.9, that is, (W2/W1) is 0.5 or more and 0.9 relationship below.In addition, the groove width W1 of inner circumferential slot 21 and external circumferential slot The relationship of 25 groove width W2 is preferably in the range of 0.6≤(W2/W1)≤0.8.

Other than circumferential slot 20, multiple translots 30 extended on tire width direction are additionally provided in tread surface 3.Make For translot 30, it is provided with central translot 31, intermediate translot 35 and tire shoulder translot 36.Wherein, central translot 31 is to be disposed in wheel Between a pair of inside circumferential slot 21 in tire width direction, and the translot that both ends are connect with a pair of inside circumferential slot 21 30.In addition, intermediate translot 35 be disposed in inner circumferential slot 21 and external circumferential slot 25 adjacent on tire width direction it Between, and the translot 30 that both ends are connect with inner circumferential slot 21 and external circumferential slot 25.In addition, tire shoulder translot 36 is outside being disposed in Outside on the tire width direction of side circumferential slot 25, and the translot 30 that one end is connect with external circumferential slot 25.The center It is arranged in translot 31, intermediate translot 35 and each comfortable tire circumferential direction of tire shoulder translot 36 multiple.

In addition, the groove width of central translot 31 is in the range of 4mm or more and 9mm or less, groove depth in 9mm or more and 18mm with Under range in.In addition, the groove width of intermediate translot 35 is in the range of 4mm or more and 9mm or less, groove depth in 2mm or more and In the range of 16mm or less.In addition, the groove width of tire shoulder translot 36 is in the range of 4mm or more and 16mm or less, groove depth 2mm with In the upper and range of 16mm or less.

Central translot 31 and intermediate translot 35 are connect with common inner circumferential slot 21, but are connect with inner circumferential slot 21 Part tire circumferential direction on position be different in central translot 31 and intermediate translot 35.Similarly, intermediate 35 He of translot In the tire circumferential direction for the part that tire shoulder translot 36 connect with common external circumferential slot 25, but connect with external circumferential slot 25 Position is different in intermediate translot 35 and tire shoulder translot 36.

Tread surface 3 formed land portion 10 by the multiple translot 30 and multiple circumferential slots 20 mark off central block 11, Intermediate mass 12 and shoulder block 13.Wherein, central block 11 is divided by adjacent central translot 31 and a pair of inside circumferential slot 21 Land portion 10 out, central block 11 is located on equatorial plane CL as a result,.In addition, intermediate mass 12 is by adjacent inner circumferential slot 21 and the land portion 10 that marks off of external circumferential slot 25 and adjacent intermediate translot 35.In addition, shoulder block 13 is to be set to tire The outside of external circumferential slot 25 in width direction, on the adjacent division of tire shoulder translot 36 and tire width direction The land portion 10 that side section is marked off by external circumferential slot 25.That is, shoulder block 13 is divided by external circumferential slot 25 and tire shoulder translot 36. It is arranged in the central block 11, intermediate mass 12 and each comfortable tire circumferential direction of shoulder block 13 multiple.

Fig. 3 is that the portion B of Fig. 2 schemes in detail.The central translot 31 in the translot 30 in land portion 10 is divided, by curved in multiple positions Folding extends to have in the circumferential extensions 33 upwardly extended in tire week and the width direction extended on tire width direction Portion 34.Specifically, a central translot 31 has part, that is, bending part 32 of bending at two positions, by by two positions The bending of bending part 32 to be formed as the shape of crankshaft shape.Position folded by the bending part 32 by two positions of central translot 31 It sets and is formed as circumferential extensions 33.Circumferential extensions 33 is formed on equatorial plane CL, circumferential scheduled relative to tire It is tilted in range to tire width direction.Circumferential extensions 33 relative to tire circumferential direction tilt angle 0 ° or more and 15 ° with Under range in.In addition, circumferential extensions 33, can be all parts and is not located on equatorial plane CL, be also possible to one The position divided is located on equatorial plane CL, and other parts are not on equatorial plane CL.

In addition, width direction extension 34 extends from the end of circumferential extensions 33 to tire width direction, it is thus connected The end of circumferential extensions 33 and inner circumferential slot 21, that is, connection bending part 32 and inner circumferential slot 21.It is detailed to be, width Direction extension 34 is set to two positions of each central translot 31, and the width direction extension 34 at two positions will be different Bending part 32 and a pair of inside circumferential slot 21 in different inner circumferential slots 21 connect.The width direction at two positions extends Respective inclined while extending on tire width direction in tire circumferential direction in portion 34.It is detailed to be, width Direction extension 34 to constitute the circumferential extensions 33 of bending part 32 together with the width direction extension 34 relative to tire The identical side in the side of width direction to tire peripheral, oblique is inclined with being different from the angle of tilt angle of circumferential extensions 33 Tiltedly.In addition, the width direction extension 34 at two positions that a central translot 31 has relative to tire width direction Tilt angle is roughly the same angle.

In addition, the position of the bad angle side of the bending part 32 of the central translot 31 in central block 11 is equipped with by from tyre surface table Face 3 is recessed and the bending part recess portion 40 of formation.The bending part recess portion 40 and the circumferential extensions 33 and width for constituting bending part 32 This both sides of direction extension 34 connection, and from circumferential extensions 33 and width direction extension 34 continuously from tread surface 3 It is recessed and is formed.The shape and chamfering of the part of the bad angle side of the bending part 32 in central block 11 implementation of bending part recess portion 40 At, on the depth direction of bending part recess portion 40 observe in the case where, be formed as with bending part 32 be an angle and with circumferential direction The part of the connection of extension 33 and the part connecting with width direction extension 34 are respectively the shape of the general triangular on side.

That is, bending part recess portion 40 by the part of the bad angle side of the bending part 32 in tread surface 3 from bending part 32 with Scheduled size is removed between circumferential extensions 33 and width direction extension 34 and is constituted.In the present embodiment, curved Folding part recess portion 40 is configured to, and is equal with the part that circumferential extensions 33 connects and with the part that width direction extension 34 connects Length.In addition, bending part recess portion 40 is formed as, the depth away from tread surface 3 in the range of 1mm or more and 8mm or less, and And in 10% or more of groove depth and 50% or less range of central translot 31.

In addition, being formed with central gap portion 45 in central block 11, which is set to width direction extension On 34 extended line, and one end is connect with bending part 32, and the other end terminates in central block 11.The central gap portion 45 is formed For groove width is size identical with the groove width of width direction extension 34, and groove depth is the groove depth phase with width direction extension 34 The shape of the channel-shaped of same depth.Therefore, in other words, width direction extension 34, central gap portion 45 and circumferential extensions 33 are configured to, and are connected with circumferential extensions in the midway of the slot formed by width direction extension 34 and central gap portion 45 The form of 33 end.

As described, the central gap portion 45 connecting with the bending part 32 of central translot 31 is formed as, along width side The 10% of the width W of the central block 11 on tire width direction is in the length EL in the direction in the formation direction of extension 34 Above and in 20% or less range.The length EL in central gap portion 45 in this case is, from the circumferential direction for constituting bending part 32 Extension side that the mutual coupling part in side of the reflex angle side of extension 33 and width direction extension 34 is risen, central gap portion 45 Upward length.

In addition, being connected to the bending part recess portion of common bending part 32 about central gap portion 45 and bending part recess portion 40 The relationship of 40 opening area A1 and the opening area A2 in central gap portion 45 are 3≤(A2/A1)≤6, that is, (A2/A1) be 3 with Upper and 6 relationships below.

Fig. 4 is the explanatory diagram to bending part spatial portion.Further, central gap portion 45 is formed as, by circumferential extensions 33, The opening area A3 for the bending part spatial portion 42 that width direction extension 34 and bending part recess portion 40 are formed and central gap portion The relationship of 45 opening area A2 is in the range of 0.03≤(A2/A3)≤0.10.Bending part spatial portion 42 in this case is, By the way that the side 41 opposite with the corner of 32 side of bending part of the triangle of the shape of bending part recess portion 40 will be used as to extend to circumferential direction Cell wall 33a in extension 33 and width direction extension 34, opposite with the cell wall of side where bending part recess portion 40, 34a and the spatial portion formed.

That is, bending part spatial portion 42 is, with the side 41 of the bending part recess portion 40 extended, circumferential extensions 33 and width Cell wall 33a, 34a in direction extension 34, opposite with the cell wall of side where bending part recess portion 40 is respectively the three of side The spatial portion of angular shape.About central gap portion 45, opening area A3 and the central gap portion 45 of the bending part spatial portion 42 The ratio (A2/A3) of opening area A2 is 0.03 or more and 0.10 relationship below.

The pneumatic tire 1 of present embodiment is formed as, the contact area ratio in middle section CA 30% or more and In 70% or less range, middle section CA is the central block that the main two sides including in tire circumferential direction are divided by central translot 31 11 and central translot 31 region.Middle section CA in this case is, with the center of the central block 11 on tire width direction That is centered on central block center BC, 10% region of the width W on the tire width direction of central block 11.That is, middle section CA is, is respectively the width W of the central block 11 on tire width direction from two sides of the central block center BC on tire width direction 5% range region.

In addition, central block center BC in this case refers to, become the two sides on the tire width direction of central block 11 The position at the center on tire width direction on tire width direction between the part of most outward side.In present embodiment Pneumatic tire in, central block center BC is located on equatorial plane CL, position of the central block center BC on tire width direction It is set to position identical with the position of equatorial plane CL.In addition, the width W of central block 11 is, it is wide in the tire of central block 11 Two sides on degree direction are located at the distance on the tire width direction on tire width direction between the part of most outward side.

It is the area relative to middle section CA, the tread surface 3 that is actually grounded in addition, contact area ratio refers to Area.In the centrally located region CA of circumferential extensions 33 that central translot 31 has.In fact, being filled when pneumatic tire 1 is grounded Some position ground connection in the tire circumferential direction of air filled tyre 1, contact area ratio is different according to each grounded part, however, at which In the case that position is grounded, the contact area ratio in middle section CA is all in 30% or more and 70% or less range.Separately Outside, the contact area ratio in middle section CA is preferably in 40% or more and 60% or less range.

In addition, central block 11 is formed as, the width W on tire width direction tyre surface spreading width TW 20% or more and In 40% or less range.Tyre surface spreading width TW in this case refers to, pneumatic tire 1 is assembled in standard rim and with mark Quasi- internal pressure air is filled in pneumatic tire 1 and when the no-load condition without applying load, the expanded view of fetus face 2 In tire width direction both ends linear distance.

In addition, standard rim refers to, " Design Rim (design wheel as defined in " applying wheel rim ", TRA as defined in JATMA Rim) " or ETRTO as defined in " Measuring Rim (measurement wheel rim) ".In addition, standard internal pressure refers to, as defined in JATMA " TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES as defined in " highest air pressure ", TRA " INFLATION as defined in the maximum value or ETRTO of (tire load limit under different cold inflation pressures) " PRESSURES (the blowing pressure) ".In addition, the width W on the tire width direction of central block 11 is preferably in tyre surface spreading width TW 25% or more and 35% or less range in.

In addition, central block 11 is formed as, the ratio of the length L in tire circumferential direction and the width W on tire width direction exist In the range of 0.9≤(L/W)≤1.1.That is, central block 11 is formed as, the length L in tire circumferential direction is relative to tire width direction On width W be 0.9 times or more and 1.1 times of shapes below.The length L of central block 11 in this case is, in central block 11 On tire is circumferential farthest away from part between tire circumferential direction on distance.

In addition, the area ratio intermediate mass 12 of central block 11 and the area of shoulder block 13 are big.In other words, intermediate mass 12 and tire shoulder Block 13 is smaller than 11 area of central block, for example, shoulder block 13 is formed as, area central block 11 area 40% or more and 60% In following range.In addition, the area of shoulder block 13 is preferably 45% or more and 55% or less relative to the area of central block 11.

Central block 11 is formed as, and maximum of the width W on tire width direction on the tire width direction of belt 7 is wide Degree is in 25% or more and 45% or less the range of maximum belt beam width BW.Maximum belt beam width BW described herein is, In each end for constituting the tire width direction two sides of multiple bandings 71,72,73,74 of belt 7, on tire width direction Position is located at the distance on the tire width direction between the end of most outward side.In addition, the tire width direction of central block 11 On width W relative to maximum belt beam width BW preferably in 30% or more and 40% or less range.

Fig. 5 is that the portion C of Fig. 2 schemes in detail.In addition, intermediate translot 35 and tire shoulder translot 36 both relative to tire width direction to Tire peripheral, oblique.Detailed to be, intermediate translot 35 is formed as, relative to tire width direction to the tilt angle of tire circumferential direction In 0 ° or more and 15 ° or less of range.In other words, intermediate translot 35 is formed as, circumferential to tyre width side relative to tire To inclination angle alpha 1 in 75 ° or more and 105 ° or less of range, that is, intermediate translot 35 is formed as, relative to tire circumferential direction To tire width direction inclination angle alpha 1 in the range of 90 ° ± 15 °.In addition, intermediate translot 35 is relative to tire circumferential direction Inclination angle alpha 1 is preferably in the range of 90 ° ± 10 °.

In addition, tire shoulder translot 36 is and intermediate 35 phase of translot to the inclined direction of tire circumferential direction relative to tire width direction For tire width direction to the identical direction of inclined direction of tire circumferential direction.The intermediate translot 35 and the formation of tire shoulder translot 36 For, intermediate translot 35 relative to the circumferential inclination angle alpha 1 and tire shoulder translot 36 to tire width direction of tire relative to wheel The relationship of the circumferential inclination angle alpha 2 to tire width direction of tire 0 °≤| α 2- α 1 | in the range of≤10 °.

In addition, the central indentation portion 46 connecting with external circumferential slot 25 is formed in intermediate mass 12, in the formation of shoulder block 13 There is the tire shoulder notch section 47 connecting with external circumferential slot 25.Wherein, central indentation portion 46 be set to in external circumferential slot 25 It is connected on the extended line of the tire shoulder translot 36 of the opposite side connection of the side in central indentation portion 46, one end and external circumferential slot 25 Connection, the other end are terminated in intermediate mass 12 and are formed.The central indentation portion 46 is formed as, on the extending direction of tire shoulder translot 36 Length ML on the outside in 150% or more of groove width W2 and 300% or less range of circumferential slot 25.

In addition, tire shoulder notch section 47 is set to the phase with the side for being connected with tire shoulder notch section 47 in external circumferential slot 25 Toss about connection intermediate translot 35 extended line on, one end is connect with external circumferential slot 25, and the other end terminates in shoulder block 13 And it is formed.The tire shoulder notch section 47 is formed as, the slot of the circumferential slot 25 on the outside of the length SL on the extending direction of intermediate translot 35 100% or more of wide W2 and 300% or less range in.

The purposes of the pneumatic tire 1 of the present embodiment constituted as described is heavy duty pneumatic vehicle tire.Should When pneumatic tire 1 is installed on vehicle, the pneumatic tire is assembled in wheel rim (rim wheel) and is installed with the state inflated In vehicle.It is assembled in the vehicle of the large size such as being installed on truck, car (bus) of pneumatic tire 1 of the state of wheel rim and makes With.

When being mounted with the vehicle driving of pneumatic tire 1, underlying tread surface 3 in one side tread surface 3 with Road surface contact, the pneumatic tire 1 rotates on one side.Vehicle by frictional force between tread surface 3 and road surface, by driving force and/ Or brake force passes to road surface or a turning is generated power to travel.Therefore, the contact area in the ground area of pneumatic tire 1 The critically important element of control stability when being to vehicle driving.On the other hand, snow road when driving, mostly using circumferential The snow column shearing force and/or edge effect of slot 20 and/or translot 30 travels, therefore the groove area in ground area is also important Element.

In addition, the total weight of vehicle changes very due to the loading condition of cargo in the vehicle of the large size such as truck, car Greatly, along with this, the load for acting on pneumatic tire 1 also changes very greatly.It is very big in the load change for acting on pneumatic tire 1 In the case of, the change in shape of the ground area of pneumatic tire 1, and as load becomes larger and ground area becomes larger.That is, with work Load for pneumatic tire 1 becomes larger, and the ground area of pneumatic tire 1 becomes larger on tire width direction and tire circumferential direction.

But the immediate vicinity on the tire width direction of tread surface 3, that is, the equatorial plane CL in tread surface 3 Nearby it is grounded when vehicle travels independently from the size with the load that acts on pneumatic tire 1.The pneumatic tire of present embodiment 1, it is equipped with inner circumferential slot 21 in the two sides of equatorial plane CL, and central block 11 is located on equatorial plane CL, thus It can ensure that the contact area near equatorial plane CL.Thereby, it is possible to act on the load of pneumatic tire 1 independently from the size Ensure the control stability in dry road traveling.

In addition, central translot 31 is bent in multiple positions, thus there is circumferential extensions 33 on equatorial plane CL, because This can ensure that in the snow road snow column shearing force and/or edge effect near equatorial plane CL when driving.Moreover, in Translot 31 is entreated, is connected with bending part recess portion 40 in the position of the bad angle side of bending part 32, therefore can be improved as easy accumulated snow Part bending part 32 near row snow property.Thereby, it is possible to independently from the size continue with the load that acts on pneumatic tire 1 Ensure the resistance between snow road ground plane when driving and snowfield surface.In addition, being formed with circumferential direction in central translot 31 Extension 33, therefore the marginal element relative to tire width direction near equatorial plane CL can be increased.Thereby, it is possible to The pneumatic tire 1 of skidding when reducing for accelerating slides laterally, in addition, can be improved the manipulation in snow road when driving Stability.

Moreover, the contact area ratio in middle section CA is 30% or more and 70% hereinafter, therefore in tread surface 3 Can with the contact area of the load for acting on pneumatic tire 1 ensured independently from the size in dry road traveling, and It can ensure the resistance between snow road snowfield surface when driving and ground plane.That is, the ground connection in middle section CA In the case that area ratio is less than 30%, the contact area in the case that load is small is small, therefore, it is difficult to ensure control stability, In the case that contact area ratio in middle section CA is more than 70%, the groove area in the case that load is small is small, therefore, it is difficult to Ensure the resistance between ground plane and snowfield surface.In contrast, the pneumatic tire 1 of present embodiment is formed as, middle section Contact area ratio in CA can either ensure to act on pneumatic tire 1 in 30% or more and 70% or less range Load it is small in the case where contact area, and can ensure the resistance between ground plane and snowfield surface.As a result, it is possible to The loading condition of cargo is independently, that is, independently improves dry ground performance and snowfield performance simultaneously with empty wagons and/or entrucking, especially It is the dry ground performance and snowfield performance when can be improved empty wagons.

In addition, in the centrally located region CA of circumferential extensions 33 of central translot 31, therefore can ensure be provided with position The groove area in middle section CA in the case where the central block 11 on equatorial plane CL.Thereby, it is possible to ensure by The ground plane when empty wagons in the case where dry ground performance when central block 11 ensures that empty wagons is arranged on equatorial plane CL With the resistance between snowfield surface.As a result, it is possible to further certainly improve dry ground performance and snowfield performance simultaneously.

In addition, bending part recess portion 40 is formed by chamfering, therefore can be horizontal in the center that pattern block is rigidly easy to be lower The part of the bad angle side of the bending part 32 of slot 31 will not make the rigidity of central block 11 that bending part recess portion 40 be arranged with reducing.As a result, It is able to suppress for the row's of raising snow property and is arranged the reduction of the dry ground performance in the case where bending part recess portion 40, it can be further true Improve dry ground performance and snowfield performance simultaneously on the spot.

In addition, bending part recess portion 40 is formed as, the part being connect with the circumferential extensions 33 of central translot 31 and and width The part that direction extension 34 connects is equal length, therefore the rigidity of central block 11 can will not be made recessed because of setting bending part Portion 40 and reduce ground setting bending part recess portion 40.Thereby, it is possible to inhibit that bending part recess portion 40 is arranged for the row's of raising property avenged In the case of dry ground performance reduction, further certainly improve dry ground performance and snowfield performance simultaneously.

In addition, bending part recess portion 40 is formed as, the depth away from tread surface 3 central translot 31 groove depth 10% or more And in 50% or less range, therefore it further can certainly take into account dry ground performance and snowfield performance.That is, in bending part recess portion In the case that 40 depth is less than the 10% of the groove depth of central translot 31, the depth of bending part recess portion 40 is excessively shallow, with central translot The difference of 31 groove depth is excessive, and it is therefore possible to be difficult to for the snow for entering central translot 31 being effectively discharged out.In addition, recessed in bending part In the case that the depth in portion 40 is more than the 50% of the groove depth of central translot 31, near the bending part recess portion 40 in central block 11 Rigidity reduces, it is possible to be difficult to ensure dry ground performance.In contrast, the depth of bending part recess portion 40 is being set in central translot In the case where in 10% or more and 50% or less range of 31 groove depth, the rigidity of central block 11 can will not be made to reduce ground really Protect row's snow property in bending part recess portion 40.As a result, it is possible to further certainly improve dry ground performance and snowfield performance simultaneously.

In addition, being formed with the central gap portion 45 connecting with the bending part 32 of central translot 31 in central block 11, therefore logical Crossing central gap portion 45 can also ensure that snow column shearing force and/or edge effect.Thereby, it is possible to further certainly improve in The ground plane near the CA of region and the resistance between snowfield surface are entreated, and further certainly improves snowfield performance.

In addition, central gap portion 45 is formed as, along the formation direction of the width direction extension 34 of central translot 31 The length EL in direction can have been substantially ensured in 10% or more of width W and 20% or less range of central block 11 Help the contact area of dry ground road holding, and improves the hauling ability on snowfield.That is, the length EL in central gap portion 45 Less than central block 11 width W 10% in the case where, the snow column shearing force in central gap portion 45 and/or edge effect less Height, therefore, it is difficult to effectively improve the resistance between ground plane and snowfield surface.In addition, the length EL in central gap portion 45 is super In the case where cross the width W of central block 11 20%, the contact area of central block 11 is possible to become too small.In contrast, exist The case where length EL in central gap portion 45 is set in 10% or more of width W and 20% or less range of central block 11 Under, being arranged with will not capable of excessively reducing the contact area of central block 11 can expect to avenge column shearing force and/or edge effect Central gap portion 45.As a result, it is possible to further certainly improve dry ground performance and snowfield performance simultaneously.

In addition, being connected to the bending part recess portion of common bending part 32 about bending part recess portion 40 and central gap portion 45 The relationship of the 40 opening area A1 and opening area A2 in central gap portion 45 is 3≤(A2/A1)≤6, therefore can make center The rigid uniform of block 11.That is, bending part recess portion 40 and central gap portion 45 are disposed in the central translot 31 on tire width direction Circumferential extensions 33 two sides, therefore in the case where (A2/A1) is less than 3 or (A2/A1) is more than 6, in central block 11 The poor rigidity of the two sides of circumferential extensions 33 becomes excessive, it is possible to lead to partial wear.In contrast, by bending part recess portion 40 Opening area A1 and the relationship of opening area A2 in central gap portion 45 the case where being set in the range of 3≤(A2/A1)≤6 Under, the poor rigidity of the two sides of circumferential extensions 33 can be reduced.As a result, it is possible to inhibit to be provided with bending part recess portion 40 and center The generation of partial wear in the case where notch section 45.

In addition, being formed with central indentation portion 46 in intermediate mass 12, it is formed with tire shoulder notch section 47 in shoulder block 13, therefore logical The snow column shearing force and/or edge effect for crossing central indentation portion 46 and tire shoulder notch section 47, can increase the wheel in ground area Resistance between near both ends in tire width direction, ground plane and snowfield surface.As a result, it is possible to improve snowfield acceleration Can, it further can certainly improve snowfield performance.

In addition, intermediate translot 35 is formed as, relative to the circumferential inclination angle alpha 1 to tire width direction of tire 75 ° with In upper and 105 ° or less of range, therefore it can be improved near the both ends on the tire width direction of ground area, opposite In the marginal element of tire circumferential direction.As a result, it is possible to further certainly improve snowfield performance.

In addition, about intermediate translot 35 and tire shoulder translot 36, inclination angle alpha 1 and the tire shoulder translot 36 of intermediate translot 35 The relationship of inclination angle alpha 20 °≤| α 2- α 1 | in the range of≤10 °, therefore can ensure arrange snow property, in addition, can be effectively Improve the snow column shearing force and/or edge effect in intermediate translot 35 and/or tire shoulder translot 36.As a result, it is possible to further true Snowfield performance is improved on the spot.

In addition, inner circumferential slot 21 and external circumferential slot 25 are formed as, the groove width W1 and external circumferential of inner circumferential slot 21 The relationship of the groove width W2 of slot 25 meets the relationship of 0.5≤(W2/W1)≤0.9, therefore can ensure by the position of middle section CA Groove area, can fully the row of performance snow property.Snowfield as a result, it is possible to improve dry ground performance, and when improving empty wagons Energy.

In addition, central block 11 is formed as, the width W on tire width direction be 20% or more of tyre surface spreading width TW and Therefore 40% hereinafter, can ensure the groove area of middle section CA, and obtain the area of biggish central block 11.As a result, It can ensure snowfield performance, and improve dry ground performance.

In addition, central block 11 is formed as, the ratio of the length L in tire circumferential direction and the width W on tire width direction exist In the range of 0.9≤(L/W)≤1.1, therefore it can ensure the rigidity of central block 11, so as to ensure control stability.That is, It is rigid in the rigidity and/or tire width direction in the tire circumferential direction of central block 11 when (L/W) is less than 0.9 or is greater than 1.1 Property is possible to become too low, and central block 11 is easy to collapse, therefore the effective grounding area of central block 11 is likely to decrease.With this phase It is right, by the ratio set of the width W on the length L and tire width direction in the tire circumferential direction of central block 11 in 0.9≤(L/W) In the range of≤1.1, thus, it is possible to ensure the rigidity of central block 11, therefore it is able to suppress the effective grounding area drop of central block 11 It is low.As a result, it is possible to further certainly improve dry ground performance and snowfield performance simultaneously.

In addition, the area of shoulder block 13 is in 40% or more of area and 60% or less range of central block 11, therefore The groove area of the frequency that can ensure to be grounded in the empty wagons shoulder zone fewer than middle section CA is cut so as to ensure to avenge column Shear force and/or edge effect.In addition, the area of the area ratio shoulder block 13 by making central block 11 is big, in ensuring Entreat the rigidity of block 11.Thereby, it is possible to inhibit the effective grounding area of central block 11 to reduce due to the rigidity of central block 11 reduces.Its As a result, it is possible to further certainly improve dry ground performance and snowfield performance simultaneously.

In addition, central block 11 is formed as, the width W on tire width direction maximum belt beam width BW 25% or more and In 45% or less range, therefore it is possible to realize on tire width direction, in the ground pressure centered on middle section CA The optimization of the width of the belt 7 in high region.Thereby, it is possible to seek the rigidity of the fetus face 2 on tire width direction Homogenization.As a result, it is possible to the driving status with vehicle independently to improve control stability.

In addition, using steel carcass material in carcass 6, therefore it can ensure the whole rigidity of pneumatic tire 1.As a result, it is possible to Control stability is independently improved with the driving status of vehicle.

In addition, the pneumatic tire 1 of present embodiment is used as heavy duty pneumatic vehicle tire, even if thus because of goods The loading condition of object and act on the load change of pneumatic tire 1 it is very big in the case where, also can be with load independently from the size Dry ground performance and snowfield performance are improved simultaneously.As a result, it is possible to the pneumatic tire 1 for improving present embodiment be installed on truck, The driving performance of vehicle in the case where the vehicle of the large size such as car.

(embodiment)

Fig. 6 A~Fig. 6 D is the chart for indicating the result of performance test of pneumatic tire.Hereinafter, about above-mentioned inflated wheel Tire 1 illustrates the evaluation test of the performance carried out to the pneumatic tire 1 of previous example and pneumatic tire 1 of the invention.Performance evaluation examination It tests and carries out about the accelerating ability i.e. test of dry ground accelerating ability on dry road surface and about the accelerating ability on snowfield That is the test of snowfield accelerating ability.

These benchmark tests pass through to carry out as got off: the tire specified in JATMA is nominally 275/ 80R22.5 specification, the pneumatic tire 1 that load factor is 151J are assembled in the wheel rim of the standard rim specified in JATMA, will be empty Atmospheric pressure is adjusted to the maximum air pressure specified in JATMA, and the test vehicle that the pneumatic tire 1 is installed on 2-D (is led Draw vehicle headstock (tractor head)) carry out test traveling.

About the evaluation method of each pilot project, pass through the acceleration of the speed interval to 5~40km/h in dry pavement Degree is measured, and makes average acceleration indexation, to evaluate dry ground accelerating ability.The bigger expression of numerical value accelerates dryly Performance is the better.It is measured by the acceleration of the speed interval to 5~20km/h on the road surface of snow consolidation (compacting), and Make average acceleration indexation to evaluate snowfield accelerating ability.The bigger expression snowfield accelerating ability of numerical value is the better.Separately Outside, in the case where the respective index of dry ground accelerating ability and snowfield accelerating ability is 105 or more, there is effective performance.

Pneumatic tire 1 to the previous example 1~3 of an example as previous pneumatic tire 1 and as inflation of the invention This 24 kinds of pneumatic tires 1 of the Examples 1 to 21 of tire 1 carry out evaluation test.These pneumatic tires 1 are formed as, central translot 31 Whether bend, whether circumferential slot 20 has amplitude, the contact area ratio in middle section CA on tire width direction and has It is different without bending part recess portion 40.Wherein, the not set bending part recess portion 40 of the pneumatic tire 1 of previous example 1~3, and in Centre translot 31 do not bend or circumferential slot 20 without in amplitude or middle section CA contact area compare not 30% with In upper and 70% or less range.

In contrast, the Examples 1 to 21 about an example as pneumatic tire 1 of the invention, central translot 31 are bent, Circumferential slot 20 has amplitude, and the contact area in middle section CA has than in the range of 30% or more and 70% or less There is bending part recess portion 40.Moreover, the pneumatic tire 1 about Examples 1 to 21, the presence or absence of central gap portion 45, central gap portion 45 length EL, the ratio of opening area A1 of the opening area A2 relative to bending part recess portion 40 in central gap portion 45, centre The presence or absence of notch section 46 and tire shoulder notch section 47, intermediate translot 35 and the inclination angle alpha 1 of tire shoulder translot 36, α 2, inner circumferential slot 21 with ratio of the width W relative to tyre surface spreading width TW of the relativeness of groove width W1, W2 of external circumferential slot 25, central block 11 Example, the aspect ratio of central block 11, shoulder block 13 area relative to central block 11 area ratio and central block 11 width It is different relative to the ratio of maximum belt beam width BW to spend W.

The result of evaluation test is carried out as shown in Fig. 6 A~Fig. 6 D using these pneumatic tires 1, it is known that Examples 1 to 21 Pneumatic tire 1 improves dry ground accelerating ability and snowfield accelerating ability relative to previous example 1~3.That is, Examples 1 to 21 Pneumatic tire 1 can improve dry ground performance and snowfield performance simultaneously.

Claims (16)

1. a kind of pneumatic tire, which is characterized in that have:

A pair of inside circumferential slot, clips equatorial plane and is disposed in two of the equatorial plane on tire width direction Side, and upwardly extended in tire week；

A pair of outside circumferential slot is disposed in the respective outside of a pair of inner circumferential slot on tire width direction, and It is upwardly extended in tire week；

Multiple center translots, both ends are connect with a pair of inner circumferential slot, and are thus had in the bending of multiple positions The circumferential extensions and the width direction extension extended on tire width direction that tire week upwardly extends；

Central block, for the land portion marked off by the central translot and the inner circumferential slot；And

Bending part recess portion, by the position of the bad angle side of the bending part of the central translot in the central block from tyre surface Surface indentation and formed, and connect with the circumferential extensions and the width direction extension,

Contact area ratio in middle section is 30% or more and 70% hereinafter, the middle section is with tire width direction On the central block center centered on, 10% region of width on the tire width direction of the central block,

The pneumatic tire is also equipped with:

Multiple intermediate translots, both ends are connect with the adjacent inner circumferential slot and the external circumferential slot；

Multiple tire shoulder translots are disposed in the outside on the tire width direction of the external circumferential slot, one end and the outside Circumferential slot connection；

Intermediate mass, for the land portion marked off by the inner circumferential slot, the external circumferential slot and the intermediate translot；With And

Shoulder block is the land portion marked off by the external circumferential slot and the tire shoulder translot,

It is formed with central indentation portion in the intermediate mass, which is set on the extended line of the tire shoulder translot, and And one end is connect with the external circumferential slot, the other end terminates in intermediate mass,

It is formed with tire shoulder notch section in the shoulder block, which is set on the extended line of the intermediate translot, and And one end is connect with the external circumferential slot, the other end terminates in shoulder block,

The length on the extending direction of the tire shoulder translot in the central indentation portion is the groove width of the external circumferential slot 150% or more and 300% hereinafter,

The length on the extending direction of the intermediate translot of the tire shoulder notch section is the groove width of the external circumferential slot 100% or more and 300% or less.

2. pneumatic tire according to claim 1,

The circumferential extensions is located in the middle section.

3. pneumatic tire according to claim 1 or 2,

The bending part recess portion is formed by chamfering.

4. pneumatic tire according to claim 1 or 2,

The bending part recess portion is formed as, and the part that connect with the circumferential extensions and connect with the width direction extension Part be equal length.

5. pneumatic tire according to claim 1 or 2,

The bending part recess portion is formed as, the depth away from the tread surface the central translot groove depth 10% or more And in 50% or less range.

6. pneumatic tire according to claim 1 or 2,

It is formed with central gap portion in the central block, which is set to the extended line of the width direction extension On, and one end is connect with the bending part, and the other end terminates in the central block.

7. pneumatic tire according to claim 6,

The central gap portion is formed as, and the length along the direction in the formation direction of the width direction extension is wide in tire It spends in 10% or more of width and 20% or less range of the central block on direction.

8. pneumatic tire according to claim 6,

About the bending part recess portion and the central gap portion, it is connected to the bending part recess portion of the common bending part Opening area A1 and the central gap portion opening area A2 relationship be 3≤(A2/A1)≤6.

9. pneumatic tire according to claim 1 or 2,

The intermediate translot is formed as, relative to the circumferential tilt angle to tire width direction of tire at 75 ° or more and 105 ° In following range.

10. pneumatic tire according to claim 1 or 2,

About the intermediate translot and the tire shoulder translot,

The intermediate translot relative to the circumferential inclination angle alpha 1 and the phase of the tire shoulder translot to tire width direction of tire The relationship of the inclination angle alpha 2 to tire width direction circumferential for tire is 0 °≤| α 2- α 1 |≤10 °.

11. pneumatic tire according to claim 1 or 2,

About the inner circumferential slot and the external circumferential slot, the groove width W1 of the inner circumferential slot and the external circumferential slot Groove width W2 relationship be 0.5≤(W2/W1)≤0.9.

12. pneumatic tire according to claim 1 or 2,

Width on the tire width direction of the central block is 20% or more and 40% or less of tyre surface spreading width.

13. pneumatic tire according to claim 1 or 2,

The ratio of the width W on length L and tire width direction in the tire circumferential direction of the central block be 0.9≤(L/W)≤ 1.1。

14. pneumatic tire according to claim 1 or 2,

The purposes of the pneumatic tire is heavy duty pneumatic vehicle tire.

15. a kind of pneumatic tire, which is characterized in that have:

A pair of inside circumferential slot, clips equatorial plane and is disposed in two of the equatorial plane on tire width direction Side, and upwardly extended in tire week；

A pair of outside circumferential slot is disposed in the respective outside of a pair of inner circumferential slot on tire width direction, and It is upwardly extended in tire week；

Multiple center translots, both ends are connect with a pair of inner circumferential slot, and are thus had in the bending of multiple positions The circumferential extensions and the width direction extension extended on tire width direction that tire week upwardly extends；

Central block, for the land portion marked off by the central translot and the inner circumferential slot；And

Bending part recess portion, by the position of the bad angle side of the bending part of the central translot in the central block from tyre surface Surface indentation and formed, and connect with the circumferential extensions and the width direction extension,

Contact area ratio in middle section is 30% or more and 70% hereinafter, the middle section is with tire width direction On the central block center centered on, 10% region of width on the tire width direction of the central block,

It is formed with central gap portion in the central block, which is set to the extended line of the width direction extension On, and one end is connect with the bending part, and the other end terminates in the central block,

The central gap portion is formed as, and the length along the direction in the formation direction of the width direction extension is wide in tire It spends in 10% or more of width and 20% or less range of the central block on direction.

16. pneumatic tire according to claim 15,

About the bending part recess portion and the central gap portion, it is connected to the bending part recess portion of the common bending part Opening area A1 and the central gap portion opening area A2 relationship be 3≤(A2/A1)≤6.