JP2007055285A - Pneumatic tire and manufacturing method of pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of improving the rigidity of a block against not only input in the longitudinal direction at the time of braking and traction, but also input in the slant lateral direction at the time of cornering without lowering water reserving and water draining functions. <P>SOLUTION: This pneumatic tire 10 furnished with a three dimensional type sipe 14 on each of blocks constituting a block pattern formed on a tread part has a plurality of first projections 2 provided on a plurality of first portions 20 elongated in the same direction out of each of the portions of one side wall surface 16 of the sipe 14 and a plurality of second projections 26 provided on a plurality of second portions 24 elongated in the same direction out of each of the portions of of the one side wall surface 16 of the sipe 14, and the elongation direction of the first portions 20 and the elongation direction of the second portions 24 are different from each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pneumatic tire and a method for manufacturing a pneumatic tire, and in particular to each block constituting a block pattern formed on a tread portion in order to improve not only a general road but also running performance on ice, etc. It relates to a three-dimensional sipe.

  In general, in a passenger car tire, in order to improve the grip performance of the tire when traveling on an icy road or the like, the surface of the block pattern formed on the tire tread surface is, for example, shown in FIG. As shown in a plan view showing a part of the block 113Z, a sipe 114Z having both ends communicating with the longitudinal groove 111 of the block 113Z is often used.

  The sipe 114Z increases the tire contact pressure by the edge effect similarly to the edge of the vertical groove 111 or the horizontal groove 112, and the block 113Z is divided into a plurality of small blocks 113k on the tire tread side by the sipe 114Z. Becomes easy to deform.

  In addition, the sipe 114Z cuts the water film and also serves as a water reservoir. When the water film is thick, the sipe 114Z becomes a water channel and facilitates drainage. Therefore, the frictional force between the road surface and the tire is increased, and the grip of the tire 110 is increased. The performance is improved and the on-ice performance of the vehicle is improved.

  As the shape of the sipe 114Z, there is conventionally known a so-called 2D (two-dimensional) sipe as shown in FIG. 12 (a perspective view showing a part of a tread surface of a conventional tire). As this 2D sipe, there is a flat or corrugated one whose shape does not change in the depth direction of the sipe.

  However, when the sipe 114Z is a 2D sipe as described above, if the number of sipes is increased to increase the friction coefficient between the tire 110 and the road surface, the rigidity of the entire block 113Z decreases, and the sipe 114Z There is a problem that falls may occur, and on the contrary, drainage and grip performance may be deteriorated.

  Therefore, in recent years, a method has been proposed in which a so-called 3D (three-dimensional) sipe whose shape changes in the sipe depth direction is formed in the block 113Z.

  That is, as shown in FIG. 13 (a diagram illustrating a 3D sipe), the block 113Z has a surface shape that is linear or corrugated and has an inclined surface in the depth direction (the tire radial direction) of the block 113Z. A method for forming the sipes 114A, 114B, and 114C has been proposed.

  When the 3D sipe is used, when the front and rear inputs such as brake and traction (force in the circumferential direction of the tire 110) are applied to the tire 110, the wall surface of the 3D sipe is brought into close contact with the inclined surface, thereby suppressing the collapse of the sipe. Therefore, the rigidity of the block 113Z can be improved.

  The sipe 114A shown in FIG. 13A is a 3D sipe having one inclined surface in the sipe depth direction, and the sipe 114B shown in FIG. 13B has two inclinations in the sipe depth direction. A sipe 114C having a surface, and a sipe 114C shown in FIG. 13C is a 3D sipe having a shape in which concavities and convexities having an equilateral triangle are continuous in the depth direction of the sipe.

  In addition to the sipe shown in FIG. 13, ridges and depressions (concave / convex) having a triangular cross section in the width direction of the tire are continuous, and the ridges and depressions are shifted by a half cycle in the sipe depth direction. There are 3D sipes having different shapes, 3D sipes having concavo-convex rows inclined on the inner wall surface of the sipe adjacent in the depth direction, and inclined in opposite directions in the tire circumferential direction.

For example, Patent Document 1 can be cited as a patent document related to a tire having a 3D sipe.
JP 2001-213123 A

  By the way, as described above, if a 3D sipe is formed on the block 113Z, the rigidity of the block 113Z is improved, but the sipe sucks up and stores the water film on ice, and when the water film is thick, It is necessary to serve as a passage for discharging water out of the ground contact surface of the tire.

  Therefore, the rigidity of the block 113Z is improved by the close contact of the wall surface of the sipe (for example, the inclined surface of the 3D sipe), but there is a problem that the water film cannot be sucked up and drained sufficiently.

  The present invention has been made in view of the above problems, and without reducing the water storage and drainage functions, not only the input in the front and rear direction during braking and traction but also the input in the diagonal and lateral directions during cornering, It is an object of the present invention to provide a pneumatic tire capable of increasing the rigidity of a block and a manufacturing method thereof.

  Invention of Claim 1 is the pneumatic tire which provided the sipe of the three-dimensional shape in each block which comprises the block pattern formed in a tread part, Among each site | part of the one side wall surface of the said sipe, Among the plurality of first protrusions provided in the plurality of first portions extending in the same direction and each portion of the one side wall surface of the sipe, the plurality of portions extending in the same direction Air having a plurality of second protrusions provided in the second part, and the extending direction of the first part and the extending direction of the second part being different from each other This is a tire.

  According to a second aspect of the present invention, in the pneumatic tire according to the first aspect, a plurality of the tires provided on the other side wall surface of the sipe so as to face each projection provided on the one side wall surface of the sipe. This is a pneumatic tire having protrusions.

  According to a third aspect of the present invention, there is provided a pneumatic tire manufacturing method in which each block constituting a block pattern formed in a tread portion includes a three-dimensional sipe. A plurality of second protrusions facing the first protrusions are provided on the other side wall surface of the sipe, and the sipe is a vulcanization mold. The protrusions are formed by cutting the tire flesh that has entered a plurality of through holes provided in the blade when the blade is extracted from the sipe. This is a method for manufacturing a pneumatic tire.

  According to the present invention, the rigidity of the block can be increased not only in the front-rear direction input during braking and traction but also in the oblique and lateral directions during cornering without deteriorating the water storage and drainage functions. Play.

  FIG. 1 is a plan view showing a tread surface of a pneumatic tire 10 according to an embodiment of the present invention, and FIG. 2 is an enlarged perspective view of the tread surface of the pneumatic tire 10.

  On the tread surface of the tire 10, a plurality of circumferential grooves (also referred to as main grooves or longitudinal grooves) 11 extending along the circumferential direction of the tire 10 indicated by the arrow A direction in FIG. A plurality of land portions (hereinafter referred to as “blocks”) 13 defined by a plurality of lateral grooves (sub-grooves) 12 extending along the width direction of the tire 10 indicated by an arrow B that intersects (for example, intersects with) the arrow B. A tread pattern is formed.

  The block 13 is formed with a plurality of lateral sipes (hereinafter simply referred to as “sipes”) 14 that divide the surface side of the block 13 into a plurality of small blocks 13m. The sipe 14 is provided in order to improve the slip property on an icy road and a snowy road, and extends in a direction along the sub-groove 12 (for example, the width direction of the tire 10).

  The sipe 14 will be described in detail.

  FIG. 3 is a perspective view showing a schematic configuration of the sipe 14, and FIG. 4 is a view taken along the arrow IV in FIG.

  The sipe 14 is a so-called 3D (three-dimensional) sipe whose shape changes in the width direction and the depth direction of the sipe 14, and one side wall surface (one side wall surface in the circumferential direction of the tire 10) 16 of the sipe 14. The unevenness is repeated by changing the inclination angle in the width direction of the tire 10, for example, the cross-sectional shape is formed in a triangular wave shape, and the unevenness is repeated by changing the inclination angle in the depth direction of the tire 10. Thus, for example, the cross-sectional shape is formed in a triangular wave shape.

  The other side wall surface 18 (the other side wall surface in the circumferential direction of the tire 10) 18 of the sipe 14 is also uneven by changing the inclination angle in the width direction of the tire 10 in the same manner as the side wall surface 16. It has a shape in which unevenness is repeated by changing the inclination angle in the depth direction of 10. Therefore, it is formed in the same shape as the one side wall surface 16.

  Further, at any position of the sipe 14, the other side wall surface 18 is provided so that the distance from the one side wall surface 16 in the circumferential direction of the tire 10 is substantially constant. Therefore, it can be said that the one side wall surface 16 and the other side wall surface 18 are provided so as to be parallel to each other.

  Of each portion of the one side wall surface 16 of the sipe 14, a plurality of portions (surfaces) 20 extending in the same direction are provided with a plurality of protrusions 22 formed in a columnar shape, for example. Yes. Each of the protrusions 22 protrudes in a direction perpendicular to the surfaces 20. Further, for example, one protrusion 22 is provided on one surface 20, but a plurality of protrusions 22 may be provided on one surface 20.

  In addition, among the portions of the one side wall surface 16 of the sipe 14, a plurality of second portions (surfaces) 24 extending in the same direction may include a plurality of portions, as in the case of the surface 20. The projection 26 is provided. Here, the extending direction of the first part 20 and the extending direction of the second part 24 are different from each other.

  Further, among the portions of the one side wall surface 16 of the sipe 14, the plurality of third portions (surfaces) 28 extending in the same direction include a plurality of portions as in the case of the surface 20. The protrusion 30 is provided. Here, the extension direction of the third part 28 is different from the extension direction of the first part 20 and the extension direction of the second part 24.

  In addition, among the portions of the one side wall surface 16 of the sipe 14, a plurality of fourth portions (surfaces) 32 extending in the same direction are included in the plurality of fourth portions (surfaces) as in the case of the surface 20. Projection 34 is provided. Here, the extension direction of the fourth part 32 is different from the extension direction of the first part 20 and the extension direction of the second part 24 and the third part 28. ing.

  Further, a plurality of protrusions are provided on the other side wall surface 18 as well as the one side wall surface 16. Each protrusion provided on the other side wall surface 18 faces each protrusion provided on the one side wall surface 16.

  Here, the shape of the side wall surface 16 of the sipe 14 will be described with an example.

  FIG. 5 is a diagram for specifically explaining the shape of the side wall surface 16 of the sipe 14.

  6 is a diagram showing a VIA-VIA cross section and a VIB-VIB cross section in FIG. 4, and FIG. 7 is a diagram showing a VII-VII cross section in FIG.

  The side wall surface 16 of the sipe 14 is formed in the shape which combined the rhombus D1. FIG. 5A is a development view of a part (one unit) 36 of the side wall surface 16 of the sipe 14, and FIG. 5B is an arrow view of the unit 36 of the side wall surface 16 of the sipe 14.

  As shown in FIG. 5 (a), one unit 36 on the side wall surface 16 of the sipe 14 is developed into a combination of four rhombuses (one rhombus L1 whose rhombus L1 is slightly longer than the other diagonal L2) D1. can do. Then, in FIG. 5 (a), each dotted line L3 is folded in a mountain, and each side L4, L5 is joined to each other, so that one of the side walls 16 of the sipe 14 is formed by four rhombuses D1 as shown in FIG. 5 (b). One unit (one unit having a quadrangular pyramid shape) 36 is formed.

  5B is a view of the side wall surface 16 of the sipe 14 viewed from the same direction (circumferential direction of the tire 10) as FIG. 4, and the point P1 shown in FIG. 5B is a quadrangular pyramid shape. It is the apex of one unit 36 of Sipe. Further, one unit 36 on the side wall surface 16 of the sipe 14 has a square shape in FIG.

  The side wall surface 16 of the sipe 14 is formed in a shape in which the one unit 36 that looks like a square is regularly arranged in the vertical and horizontal directions (the depth direction of the sipe 14 and the width direction of the sipe 14).

  As can be understood from FIG. 5A, each of the protrusions 22, 26, 30, and 34 is disposed, for example, at the center of each rhombus D1, but is not necessarily disposed at the center. In order to make the protrusions of the side wall surfaces 16 and 18 face each other, they should be arranged at an appropriate biased position. In FIG. 4, the point P <b> 1 is the apex of the side wall surface 16 of the sipe 14, and the point P <b> 2 indicates the valley point (deepest point) of the side wall surface 16 of the sipe 14.

  In FIG. 3 to FIG. 5, for convenience of explanation, the transition part (boundary of each diamond D1, boundary of each unit 36) of the side wall surface 16 of the sipe 14 is drawn with a straight line (solid line or dotted line). At the transition part, it seems that the expansion direction of the surface changes suddenly, but in fact, at each transition part, as shown in FIGS. 6 and 7, the surface passes through the arc-shaped part. The direction of stretching has changed.

  Next, the manufacturing method of the sipe 14 and each protrusion 22, 26, 30, 34 is demonstrated.

  FIG. 8 is a diagram for explaining a method of manufacturing the sipe 14 and the protrusions 22, 26, 30, and 34.

  As shown in FIG. 8A, a blade 38 is embedded (installed) in a vulcanization mold, and the tire 10 is vulcanized. The sipe 14 is formed by this vulcanization.

  Next, when the blade 38 is extracted in the direction indicated by the arrow in FIG. 8A, the meat portion of the tire 10 that has entered the plurality of through holes 40 provided in the blade 38 is cut to form the protrusions 22 and the like. . The protrusions 22 and the like formed in this way face each other (see FIGS. 7 and 8B).

  In FIG. 4, protrusions are provided on all four surfaces of the quadrangular conical unit 36, but it is not always necessary to provide protrusions on all surfaces.

  For example, as shown in FIG. 9 (a diagram illustrating a modification of the installation form of the protrusions), the protrusions may be thinned out as appropriate. That is, instead of providing projections on all the slopes of the quadrangular pyramid units 36, the projections may be provided on some of the slopes of each of the quadrangular pyramid units 36 with a certain regularity in a balanced manner. . In addition, the black circle in FIG. 9 has shown protrusion.

  Further, the unit 36, the projections 22, 26, etc. may be provided over the entire side walls 16, 18, or the unit 36, the projections 22, 26, etc. may be provided on a part of the side walls 16, 18.

  Next, test results of the tire 10 according to the present embodiment will be described.

  FIG. 10 is a diagram for explaining a test result of the tire 10.

  A tire having a block with an existing sipe shape and a tire with a block with a sipe shape according to the present embodiment are mounted on a test vehicle to improve braking / acceleration / steering stability on an icy road. A test was conducted to evaluate the performance on ice, and a general road performance evaluation was performed by conducting a steering stability test on an asphalt road (dry; DRY, wet; WET).

  In the on-ice braking test, the braking distance from the initial speed of 20 km / h until full braking was applied to the stationary state was measured, and the average deceleration calculated from the initial speed and the braking distance was evaluated.

  In the on-ice acceleration test, the evaluation was performed based on an average acceleration during acceleration from 10 km / h to 45 km / h. In the steering stability test, G was measured at the time of cornering, and the evaluation was performed using the gradient average value of G (acceleration). The evaluation result is expressed as an index when the conventional 2D sipe is set to 100, and the larger the index, the better the performance.

  The tire size used for the test was 195 / 65R15, and the internal pressure of the tire was 200 kPa. Further, the sipe corresponding to the 3D sipe E has a ridge and depression (concave / convex) having a triangular cross section in the tire width direction, and the ridge and the depression are arranged with a half-cycle shift in the sipe depth direction. It is a 3D sipe of shape.

  As is apparent from the table of FIG. 10, the 3D sipe according to the present embodiment (the sipe provided with the protrusion as shown in FIG. 9A); the predetermined slope of each unit 36 facing the apex P1 In addition to the front and rear input directions such as brake and traction, the sipe provided with protrusions is effective not only for diagonal and lateral inputs during cornering, but on ice, general road performance (DRY, It was confirmed that (WET) was improved.

  According to the tire 10, the projections 22, 26 and the like are provided on the inner walls (each side wall surface) 16, 18 of the three-dimensional sipe (3D sipe) 14. Even if there is, the opposing side wall surfaces 16, 18 of the sipe 14 support each other through the projections 22, 26, etc., and the opposing side wall surfaces 16, 18 of the sipe 14 are in close contact with each other. Therefore, the sipe 14 can be prevented from falling down, and the rigidity of the block 13 can be increased. Moreover, since each side wall surface 16 and 18 which the sipe 14 opposes supports through the protrusions 22 and 26, it can prevent that the sipe 14 is crushed and can prevent the water storage and drainage function of the sipe 14 from being deteriorated. can do.

  Further, according to the tire 10, the protrusions 22 and the protrusions 26 are provided on the inner walls 16 and 18 of the three-dimensional sipe 14, and the extending direction of the portion 20 where the protrusions 22 are provided, Since the extending directions of the portions 24 where the protrusions 26 are provided are different from each other, not only when the tire 10 is input in the front-rear direction due to braking or traction, but also in the lateral and oblique directions due to cornering. Even if there is an input, it is possible to prevent the opposing side wall surfaces 16 and 18 of the sipe 14 from sticking to each other (the sipe 14 being crushed).

  That is, even if there is an input of force in various directions to the tire 10, the force of various vectors can be received by the protrusions 22 and 26, so that the sipes 14 can be prevented from being crushed. The rigidity, the water storage capacity of the sipe 14, and the drainage can be maintained in a good state.

  Further, when the blade 38 for forming the sipe 14 is extracted from the sipe 14, the flesh portions of the tire 10 that have entered the plurality of through holes 40 provided in the blade 38 are cut, whereby the protrusions 22, 26. Therefore, the plurality of pairs of protrusions 22 and 26 facing each other can be easily formed on the side wall surfaces 16 and 18 of the sipe 14 in such a manner that they face each other accurately.

1 is a plan view showing a tread surface of a pneumatic tire according to an embodiment of the present invention. It is the perspective view which expanded the tread surface of the pneumatic tire. It is a perspective view which shows schematic structure of a sipe. It is IV arrow line view in FIG. It is a figure explaining concretely the shape of the side wall surface of a sipe. It is a figure which shows the VIA-VIA cross section in FIG. 4, and a VIB-VIB cross section. It is a figure which shows the VII-VII cross section in FIG. It is a figure explaining the manufacturing method of a sipe and a protrusion. It is a figure which shows the modification of the installation mode of a processus | protrusion. It is a figure explaining the test result of a tire. It is a top view which shows a part of tread surface of the conventional tire. It is a perspective view which shows a part of tread surface of the conventional tire. It is a figure which illustrates 3D sipe.

Explanation of symbols

10 Tire 13 Block 14 Sipe 16, 18 Side wall surface 20, 24, 28, 32 Site 22, 26, 30, 34 Protrusion 38 Blade 40 Through hole

Claims (3)

In a pneumatic tire provided with a three-dimensional shape sipe in each block constituting the block pattern formed in the tread portion,
A plurality of first protrusions provided at a plurality of first portions extending in the same direction among the respective portions of one side wall surface of the sipe;
A plurality of second protrusions provided at a plurality of second portions extending in the same direction among the portions of one side wall surface of the sipe;
A pneumatic tire characterized in that the extending direction of the first part and the extending direction of the second part are different from each other. The pneumatic tire according to claim 1,
A pneumatic tire comprising a plurality of protrusions provided on the other side wall surface of the sipe so as to face each protrusion provided on one side wall surface of the sipe. In the method of manufacturing a pneumatic tire provided with a three-dimensional sipe in each block constituting the block pattern formed in the tread portion,
A plurality of first protrusions are provided on one side wall surface of the sipe,
A plurality of second protrusions facing the first protrusions are provided on the other side wall surface of the sipe,
The sipe is formed by a blade embedded in a vulcanization mold, and each protrusion has a tire flesh that has entered a plurality of through holes provided in the blade when the blade is extracted from the sipe. A method for manufacturing a pneumatic tire, characterized by being formed by cutting.

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