JP2007161028A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve rolling resistance performance and resisting performance against uneven wear by suppressing a buckling deformation while an excellent high-speed running performance is secured. <P>SOLUTION: An inner land part 13 consisting of a rib 15 stretching substantially continuously without interruption in the tire circumferential direction is formed between a longitudinal main groove Gc in the center passing the tire equator and side longitudinal main grooves Gs extending on both sides of Gc. A reinforcement 20 formed from a sponge band stretching in the circumferential direction is bonded fast to the tread inner cavity surface Si by means of a bonding agent 21. The reinforcement 20 is embodied as having a double-peak section furnished with a bottom part 23 whose portion leading from a fixation surface 22 has a smaller thickness and which is positioned under the central longitudinal main groove Gc, and with crest parts 24 for reinforcing which are positioned on both sides of the part 23, whose portion leading from the fixation surface has a larger thickness, and which are positioned under the land part 13 and suppress the buckling deformation of the inner land part 13. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pneumatic tire capable of suppressing rolling deformation and improving rolling resistance and wear resistance by fixing a reinforcing body made of a strip-like sponge material extending in the tire circumferential direction to a lumen surface of a tread portion. .

  In a high-performance tire for a passenger car, as shown in FIG. 6A, a vertical main groove including a central vertical main groove a on the tire equator C and vertical main grooves b on both outer sides in the tread portion, as shown in FIG. And a land portion c disposed between the central vertical main groove a and the vertical main groove b on the side is formed of a rib body extending substantially continuously without being interrupted in the tire circumferential direction. It is hoped to do. This is because when the wet performance is improved by providing the central longitudinal main groove a on the tire equator C where drainage is most required, the land portion c is formed of a rib body so that the vehicle travels straight at high speed. This is because excellent high-speed running performance such as increased performance can be obtained.

  On the other hand, when the tire contacts the ground, as shown in FIG. 6B, the convex arc-shaped tread surface is compressed and flattened along the road surface. At this time, when the inner land portion c is a rib body, the so-called buckling deformation in which the inner land portion c is curved inward in the tire radial direction and is lifted from the ground contact surface without sufficiently absorbing the compression deformation. j is likely to occur. As a result, energy loss is increased, causing disadvantages in rolling resistance performance, and disadvantageous in uneven wear resistance performance such as uneven contact pressure.

  Therefore, the present invention is based on the fact that a reinforcing body made of a band-like sponge material having a cross-section of two cross sections is fixed to the inner surface of the tread portion by an adhesive with the mountain portion positioned below the land portion inside. Reinforcement body and adhesive solidification can reinforce the inner land part, suppress buckling deformation of the inner land part, and improve rolling resistance performance and uneven wear resistance performance while ensuring excellent high-speed running performance It aims at providing a possible pneumatic tire.

JP 2005-262920 A

In order to achieve the above object, according to the invention of claim 1 of the present application, the tread portion is provided with a vertical main groove including a central vertical main groove passing through the tire equator and vertical main grooves on the side passing through both sides thereof. By the pneumatic tire which formed the inner land portion between the central vertical main groove and the vertical main groove on the side,
The inner land portion is formed as a rib body that extends substantially continuously without being interrupted in the tire circumferential direction by not including a through transverse groove that crosses between the central longitudinal main groove and the longitudinal main groove on the side. As
A reinforcing body made of a band-shaped sponge material extending in the tire circumferential direction and having a radially outer peripheral surface as a fixed surface bonded to the lumen surface of the tread portion via an adhesive is attached to the lumen surface of the tread portion,
In addition, the reinforcing body has a small thickness from the fixed surface and a trough disposed below the central vertical main groove, and is positioned on both sides of the trough and has a large thickness from the fixed surface. In addition, by being arranged under the inner land portion, it is characterized in that it has a double-sectioned cross section including a reinforcing mountain portion that suppresses buckling deformation of the inner land portion.

  In the invention of claim 2, the peak portion has a maximum thickness Ta from the fixed surface of 10.0 to 50.0 mm, and the valley portion has a minimum thickness Tb from the fixed surface of 1.0 to 50.0 mm. The pneumatic tire according to claim 2, wherein the pneumatic tire is ˜15.0 mm.

  According to a third aspect of the present invention, the land portion extends inward in the tire axial direction from a starting end portion opened by the vertical main groove on the side, and 1.0 mm outward in the tire axial direction from the central vertical main groove. It is characterized by having a transverse groove that is interrupted at the terminal end that separates the distance L described above.

  According to a fourth aspect of the present invention, the inner land portion continuously extends in the tire circumferential direction with a groove width smaller than 1.0 mm between the end portion of the lateral groove and the central vertical main groove. It is characterized by having vertical narrow grooves.

  As described above, the reinforcing member made of a band-like sponge material having a two-section cross section is fixed to the inner surface of the tread portion by an adhesive, with the peak portion positioned below the land portion in the inner portion, as described above. Therefore, the reinforcement body and the adhesive material can be solidified to reinforce the lower portion of the inner land portion, and buckling deformation of the inner land portion at the time of grounding can be suppressed. As a result, it is possible to improve rolling resistance performance and uneven wear resistance performance while securing excellent high-speed running performance due to the inner land portion being a rib body.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a developed view showing a tread surface of a pneumatic tire according to the present invention, and FIG. 2 is an enlarged view showing a part thereof.

  As shown in FIG. 1, the pneumatic tire 1 includes a longitudinal main groove including a central longitudinal main groove Gc passing through the tire equator C and longitudinal main grooves Gs and Gs passing through both outer sides thereof in the tread portion 2. By providing G, the inner land portion 13 is formed between the central vertical main groove Gc and the side vertical main groove Gs.

  In this example, the vertical main groove G is composed of a central vertical main groove Gc and side vertical main grooves Gs and Gs, whereby the tread portion 2 is connected to the land portions 13 and 13 and the side vertical main grooves Gs and Gs. The case where it divides | segments into the outer land parts 14 and 14 outside a tire axial direction rather than the main groove Gs is illustrated. The longitudinal main groove G is a drainage groove having a groove width Wg of 3.0 mm or more, preferably 5.0 mm or more and a groove depth Hg of 6.0 mm or more, preferably 7.0 mm or more, and enhances the drainage effect. Therefore, it is preferable to adopt a straight groove extending linearly in the tire circumferential direction. A zigzag groove may be adopted as required.

  Further, the inner land portion 13 does not have a through horizontal groove that crosses between the central vertical main groove Gc and the side vertical main groove Gs, thereby extending substantially continuously without being interrupted in the tire circumferential direction. The rib body 15 is formed.

  In the present embodiment, as shown in FIG. 2, the inner land portion 13 extends inward in the tire axial direction from the start end E1 that opens at the longitudinal main groove Gs on the side, and the central longitudinal main groove Gc. A lateral groove 16 is provided that is interrupted by a terminal end E2 that separates a distance L of 1.0 mm or more from the tire axial direction outside. The lateral groove 16 is formed as an inclined lateral groove in which the angle θ with respect to the tire circumferential direction is reduced continuously or stepwise from the start end E1 toward the end end E2. The angle θ of the lateral groove 16 at the start end E1 is in the range of 30 to 90 °, and the angle θ at the end E2 is in the range of 0 to 60 °. In particular, in this example, the lateral groove 16 includes a first lateral groove 16A having a large groove length along the groove center line and a second lateral groove 16B having a small groove length. The case where the lateral grooves 16A and 16B are alternately arranged in the tire circumferential direction is illustrated. The first and second lateral grooves 16A and 16B share the terminal end E2 by being connected to each other at or near the terminal end E2.

  Thus, in the inner land portion 13, there is no through lateral groove, and each lateral groove 16 ends away from the central vertical main groove Gc, so that the inner land portion 13 extends in the tire circumferential direction. The rib body 15 extends substantially continuously without interruption. The term “substantially” is to allow the inner land portion 13 to be interrupted in the tire circumferential direction by, for example, siping that closes the groove width at the time of ground contact. Preferably, however, it is desirable not to have such siping. Thus, since the inner land portion 13 is the rib body 15, high circumferential rigidity can be ensured, and excellent high-speed running performance such as improving straightness at high speed running can be exhibited. In addition, since the central longitudinal main groove Gc is provided on the tire equator C where drainage is most required, the wet performance can be improved. In particular, in this example, the lateral groove 16 is formed as an inclined lateral groove in which the angle θ with respect to the tire circumferential direction is gradually decreased toward the inner side in the tire axial direction, so that the reduction in the circumferential rigidity of the rib body 15 is minimized. However, the rib body 15 can also ensure sufficient drainage and can improve both high-speed running performance and wet grip performance.

  In the inner land portion 13, it is preferable from the viewpoint of the high speed traveling performance to set a so-called sea area ratio (negative ratio) as low as 10 to 30%. As is well known, this sea area ratio (negative ratio) is defined by the ratio S1 / S of the total ground contact area S, which is a region within the outer periphery surrounding the ground contact surface, and the sea area S1 formed by the tread groove in this region. The

  If the distance L in the tire axial direction between the terminal end E2 of the lateral groove 16 and the central longitudinal main groove Gc is less than 1.0 mm, the circumferential rigidity of the rib body 15 is insufficient and the high-speed running performance is deteriorated. Invite. Therefore, it is preferably 2.0 mm or more, more preferably 3.0 mm or more. On the other hand, if the distance L exceeds 15.0 mm, drainage tends to decrease at this portion, which is not preferable. In this example, in order to prevent the occurrence of railway wear in the central vertical main groove Gc between the terminal end E2 and the central vertical main groove Gc, the groove width is smaller than 1.0 mm and in the tire circumferential direction. A vertically extending narrow groove (including siping) 17 is provided.

  On the other hand, as shown in FIG. 1, the outer land portion 14 includes a penetrating lateral groove 18 that crosses between the longitudinal main groove on the side and the tread end TE. The block row 19R is arranged in the direction.

  Next, in the pneumatic tire 1 of the present invention, as shown in FIG. 3, a reinforcement made of a strip-like sponge material extending in the tire circumferential direction on the lumen surface Si of the tread portion 2 (hereinafter referred to as the tread lumen surface Si). The body 20 is fixed via the adhesive 21.

  The pneumatic tire 1 includes a carcass 6 extending from the tread portion 2 through the sidewall portion 3 to the bead core 5 of the bead portion 4, and a belt layer 7 disposed inside the tread portion 2 and radially outside the carcass 6. It has a well-known structure. The carcass 6 is formed from one or more carcass plies 6A in which carcass cords are arranged at an angle of, for example, 75 to 90 ° with respect to the tire circumferential direction, and in this example, one carcass ply 6A. It is folded back and locked. The belt layer 7 comprises two or more belt plies arranged in an angle of, for example, 10 to 35 ° with respect to the tire circumferential direction, in this example, two belt plies 7A and 7B. By intersecting, the belt rigidity is increased, and the tread portion 2 is reinforced strongly with a hoop effect. In this example, a band layer 8 in which a band cord is spirally wound in the tire circumferential direction is disposed on the outer side of the belt layer 7 for the purpose of improving steering stability. The belt layer 7 and the band layer 8 are collectively referred to as a tread reinforcing cord layer. In the tread rubber 2G disposed outside the tread reinforcing cord layer and forming the tread surface, the tread rubber thickness t on the inner land portion 13 is preferably in the range of 9.0 to 12.0 mm. If it is less than 9.0 mm, the rubber thickness at the groove bottom of the vertical main groove G becomes too small, which may cause damage at the groove bottom. Conversely, if it exceeds 12.0 mm, it sufficiently absorbs deformation on the ground contact surface. However, the buckling is deteriorated, and the heat generation in the tread portion is increased, so that the high-speed durability tends to be impaired.

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In addition, the reinforcing body 20 has a fixing surface 22 whose outer peripheral surface in the radial direction is bonded to the tread lumen surface Si. Further, as shown in FIG. 4, the reinforcing body 20 includes a valley portion 23 having a small thickness T from the fixed surface 22, and a thickness located on both sides of the valley portion 23 and from the fixed surface 22. It is formed in the shape of a double cross section having ridges 24, 24 with a large T. Here, the trough 23 and the crest 24 are the minimum thickness Tb in the trough 23 (minimum value of the thickness T) and the maximum thickness Ta of the crest 24 (maximum value of the thickness T). The average thickness is defined as a reference KL, a portion having a thickness smaller than the reference KL is defined as a valley portion 23, and a portion having a thickness greater than the reference KL is defined as a peak portion 24.

  And in the reinforcement body 20, while the said trough part 23 is distribute | arranged under the said center vertical main groove | channel Gc, the said peak part 24 is distribute | arranged under the said land part 13 inside.

  Here, when the tire contacts the ground, the convex arc-shaped tread surface is compressed and flattened along the road surface. At this time, as described above, when the inner land portion 13 forms the rib body 15, the compressive deformation cannot be sufficiently absorbed, and the inner land portion 13 tends to cause so-called buckling deformation that rises from the ground contact surface. There is. On the other hand, in the present invention, the reinforcing body 20 extending in the circumferential direction is fixed to the tread lumen surface Si via the adhesive 21. Although the reinforcing body 20 is formed of a sponge material, the reinforcing body 20 has a two-sectioned cross section including two ridges 24 having a large thickness, and the ridges 24 are located under the land portion 13 inside. The tread lumen surface Si side can be reinforced by the interaction with the arrangement of the adhesive and the adhesive solidifying, and buckling deformation in the land portion 13 can be effectively suppressed.

  As a result, energy loss due to buckling deformation can be reduced to improve the rolling resistance performance, and the ground contact pressure in the land portion 13 can be made uniform to improve uneven wear resistance performance. Further, since the reinforcing body 20 is made of a sponge material, heat storage is large, which is disadvantageous for high-speed durability. However, the valley 23 is formed between the ridges 24 and 24, and the heat radiation effect is improved by increasing the surface area and the heat storage is reduced by dividing the thick portion into left and right, so that high-speed durability can be maintained. And since the said trough part 23 is formed under the center vertical main groove Gc which becomes unnecessary reinforcement | strengthening, it can maintain the said high-speed durability, ensuring the buckling suppression effect, and also a trough part Since the weight is reduced by 23, the rolling resistance performance is advantageous.

  The adhesive is not particularly restricted, and various synthetic rubber materials can be used, for example, but a double-sided pressure-sensitive adhesive tape can be suitably employed from the viewpoint of the pasting work efficiency.

  Here, in order to effectively exhibit the above-described effect, the maximum thickness Ta of the peak portion 24 is 10.0 to 50.0 mm, and the minimum thickness Tb of the valley portion 23 is 1.0 to 15. It is preferably 0 mm. If the maximum thickness Ta is less than 10.0 mm, the buckling suppressing effect cannot be sufficiently exhibited. If the maximum thickness Ta exceeds 50 mm, no further suppressing effect on the buckling can be expected, and heat storage increases, which is disadvantageous for high-speed durability. Further, when the minimum thickness Tb is 1.0 mm, the strength is insufficient, and the productivity of the reinforcing body 20 and the workability of bonding the reinforcing body 20 to the tire tend to be impaired. Conversely, when the thickness exceeds 15.0 mm, This is disadvantageous for high-speed durability and rolling resistance performance.

  Further, the radially inner peripheral surface of the reinforcing body 20 extends along a wavy curve 25 in which the crests 24 and troughs 23 are alternately repeated, and the inner peripheral surface is formed by two pitches of the wavy curve 25. ing. Thereby, the manufacturing efficiency of the reinforcement body 20 can be improved. The wavy curve 25 is more preferably a trapezoidal wave shape combining straight lines as in this example from the viewpoint of manufacturing efficiency, but may be a sine wave curve, for example.

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Further, in this specification, as shown in FIG. 3, the inner land portion region Ys defined between the radial lines n and n taken from both ends in the tire axial direction on the tread surface of the inner land portion 13 is defined as The center longitudinal main groove region Yc defined between the radial lines m and m, which are defined below the inner land portion 13 and on the tread surface of the center longitudinal main groove Gc from both ends in the tire axial direction, It is called below the vertical main groove Gc. At this time, in the reinforcing body 20, the width W1 in the tire axial direction of the mountain portion 24 arranged in the inner land region Ys is set to 50 which is the width W2 in the tire axial direction of the inner land region Ys. % Or more, more preferably 60% or more, is preferred for suppressing buckling. Further, in the trough 23 arranged in the central vertical main groove region Yc, the width W3 in the tire axial direction is set to 80 to 130% of the width W4 in the tire axial direction of the central vertical main groove region Yc. Is preferable from the viewpoint of high-speed durability.

  Next, the reason why the sponge material is used as the reinforcing body 20 is that the increase in weight can be minimized and the rolling resistance performance is advantageous, and the specific gravity is in the range of 0.005 to 0.060. Can be preferably used.

  The sponge material is a sponge-like porous structure, for example, in addition to so-called sponge itself having open cells in which rubber or synthetic resin is foamed, animal fibers, plant fibers or synthetic fibers are entangled and integrally connected. Includes web-like ones. The “porous structure” includes not only open cells but also closed cells. Preferably, a synthetic resin sponge such as an ether polyurethane sponge, an ester polyurethane sponge, a polyethylene sponge, a rubber sponge such as a chloroprene rubber sponge (CR sponge), an ethylene propylene rubber sponge (EDPM sponge), a nitrile rubber sponge (NBR sponge), etc. Polyurethane sponges, particularly ether-based polyurethane sponges, are particularly preferred from the viewpoints of lightness, foam controllability, durability, and the like.

  Further, when a sponge material is used as the reinforcing body 20, since this sponge material is also excellent in vibration proofing and sound absorbing properties, it also has an effect of absorbing and relaxing resonance sound energy (vibration energy) generated in the tire lumen. Can play. As a result, it can be expected to reduce road noise, such as suppressing cavity resonance in the tire lumen.

  As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.

  A reinforcing body having the specifications shown in Table 1 is bonded to the tread inner surface of a radial tire for a passenger car with a tire size 215 / 45R17 having the tread pattern shown in FIG. 1, and the rolling resistance performance, wear resistance performance, uniformity, road of the tire Noise was measured and compared with each other.

  In addition, as Comparative Example 1, a material to which a reinforcing body was not bonded was used. In Comparative Example 2, as shown in FIG. 5 (A), a wide reinforcing body is used which is formed only by thick ridges 24 and ends on the outer side in the tire axial direction below the inner land 13. Further, in Comparative Example 3, as shown in FIG. 5B, a reinforcing body in which the peak portion 24 is arranged on the outer side in the tire axial direction from the inner land portion 13 was used. Further, in Comparative Example 4, as shown in FIG. 5C, a narrow reinforcing body that is formed only by the thick peak portion 24 and ends at the bottom of the inner land portion 13 is used.

  As the reinforcing body, an ether polyurethane sponge having a specific gravity of 0.039 made by INOAC (model number ESH2) was used, and a double-sided adhesive tape made by NITTO DENKO (model number 5000NS) was used as an adhesive.

(1) Rolling resistance performance;
Using a rolling resistance tester, filling a rim (17 × 7.0JJ) and internal pressure (230 kPa), measuring rolling resistance under the conditions of longitudinal load (4.2 kN) and speed (80 km / h), a comparative example Expressed as an index when 1 tire is taken as 100. A larger index is better.

(2) Wear resistance performance:
Install tires on all wheels of a vehicle (domestic 2500cc FR car) under the conditions of rim (17 × 7.0JJ) and internal pressure (200 kPa), and drive on the roads in general roads and expressways for a total of 3000 km. The amount of wear at the part was measured and displayed as an index when the tire of Comparative Example 1 was taken as 100. A larger index is better.

(3) Uniformity:
Using a uniformity tester, RFV was measured under the conditions of (17 × 7.0 JJ), internal pressure (200 kPa), and longitudinal load (4.1 kN), and the increase / decrease value based on Comparative Example 1 is shown. + (Plus) display means that RFV is high

(4) Road noise:
Tires are mounted on all wheels of a vehicle (domestic 2500cc FR vehicle) under the conditions of rim (17 × 7.0JJ) and internal pressure (200kPa), and a road noise measurement path (asphalt rough road) with one passenger Was run at a speed of 60 km / H. The vehicle interior noise at that time was measured at the driver's seat window side ear position, and the sound pressure level of the peak value of the air column resonance sound in the vicinity of 240 Hz was shown as an increase / decrease value based on Comparative Example 1. A + (plus) display means an increase in road noise.

It is a development view showing the tread surface of the pneumatic tire of the present invention, It is an enlarged view which expands and shows a part. It is a meridional section of a pneumatic tire. It is an expanded sectional view which shows a reinforcement body with a tread part. (A)-(C) are sectional drawings which show the comparative example of Table 1. FIG. (A), (B) is drawing explaining background art.

Explanation of symbols

2 Land part 15 in tread part 13 Rib body 16 Horizontal groove 18 Vertical narrow groove 20 Reinforcing body 21 Adhesive material 22 Fixing surface 23 Valley part 24 Mountain part C Tire equator E1 Start end part E2 End part Gc Central longitudinal main groove Gs side Longitudinal groove G Longitudinal groove Si Lumen surface of the tread

Claims (4)

By providing a vertical main groove including a central vertical main groove passing through the tire equator and a vertical main groove on the side passing through both outer sides of the tread portion, the central vertical main groove and the side vertical main groove are provided. It is a pneumatic tire that forms an inner land part in between,
The inner land portion is formed as a rib body that extends substantially continuously without being interrupted in the tire circumferential direction by not including a through transverse groove that crosses between the central longitudinal main groove and the longitudinal main groove on the side. As
A reinforcing body made of a band-shaped sponge material extending in the tire circumferential direction and having a radially outer peripheral surface as a fixed surface bonded to the lumen surface of the tread portion via an adhesive is attached to the lumen surface of the tread portion,
In addition, the reinforcing body has a small thickness from the fixed surface and a trough disposed below the central vertical main groove, and is positioned on both sides of the trough and has a large thickness from the fixed surface. In addition, a pneumatic tire characterized by having a double-sectioned cross section including a reinforcing mountain portion that suppresses buckling deformation of the inner land portion by being disposed under the inner land portion.   The peak portion has a maximum thickness Ta from the fixed surface of 10.0 to 50.0 mm, and the valley portion has a minimum thickness Tb from the fixed surface of 1.0 to 15.0 mm. The pneumatic tire according to claim 2, characterized in that:   The inner land portion extends inward in the tire axial direction from a starting end portion opened by the vertical main groove on the side, and is a terminal portion that separates a distance L of 1.0 mm or more from the central vertical main groove outward in the tire axial direction. The pneumatic tire according to claim 1, further comprising a lateral groove that is interrupted at a point.   The inner land portion has a vertical narrow groove having a groove width smaller than 1.0 mm and continuously extending in the tire circumferential direction between the end portion of the horizontal groove and the central vertical main groove. The pneumatic tire according to any one of claims 1 to 3.

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