JP2011105135A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of effectively improving the deterioration of slipping-out of a metal mold in vulcanization molding, without excessively enhancing rigidity of a block and a rib during wear development, by restraining reduction in block rigidity in a new article by sipes. <P>SOLUTION: Since the rigidity of the block can be secured by a bending part 14 of the sipes 12, falling-in of the block in the new article can be restrained. The bending part 14 is arranged only in both end parts in the length direction of the sipes 12, and since a plane part 13 is arranged in a central part in the length direction of the sipes 12, the block rigidity by the bending part 14 does not become excessively high during the wear development. The metal mold can be easily slipped out in the vulcanization molding by the plane part 13. In its case, since a part (an extension part 13a) of the plane part 13 is formed so as to reach up to both ends in the length direction of the sipes 12, even if the bending part 14 is arranged in both end parts in the length direction of the sipes 12, easiness-to-slip out of the metal mold is not reduced. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a pneumatic tire used in, for example, passenger cars, trucks, buses and the like.

  Generally, in this type of pneumatic tire, a plurality of sipes extending in the tire width direction are provided in the tread block, and the braking performance on wet road surfaces and on ice surfaces is improved by the edge effect and drainage effect of the sipes. ing. However, when a sipe is provided, the rigidity of the block is lowered, so that when new, the wear due to the collapse of the block and the steering stability on the dry road surface are reduced. In addition, there is a sipe that has a three-dimensional shape, such as forming a sipe, to suppress the collapse of the block to increase the rigidity of the block. Since the rigidity of the block is increased due to the deterioration of the rubber, the rigidity of the block is excessively increased by the three-dimensional sipe, and the braking performance on the wet road surface and the road surface on ice is greatly reduced. Furthermore, in the three-dimensional sipe, since the mold removal at the time of vulcanization molding is worse than that in the two-dimensional sipe, the block is easily damaged when the mold is removed.

  Therefore, by providing a flat portion having a two-dimensional shape at the center in the length direction of the sipe, and providing a three-dimensional bent portion having irregularities in the sipe width direction at both ends in the length direction of the sipe, As a result, the rigidity of the block is ensured and the deterioration of the mold removal is suppressed by the flat portion (see, for example, Patent Document 1).

JP 2000-255219 A

  However, as described above, even if a plane portion having a two-dimensional shape is provided at the center portion in the length direction of the sipe, both ends in the length direction of the sipe are formed only of a three-dimensional bent portion. There has been a problem that the deterioration of mold loss cannot be improved and block damage cannot be effectively prevented.

  The present invention has been made in view of the above-mentioned problems, and the object of the present invention is to suppress a decrease in rigidity of the new block or rib due to sipe, and excessively increase the rigidity of the block or rib during the progress of wear. An object of the present invention is to provide a pneumatic tire that does not become high, and that can effectively improve the deterioration of mold release during vulcanization molding.

  In order to achieve the above-mentioned object, the present invention has a sipe in the tread block and / or rib, a flat portion is provided at the center in the longitudinal direction of the sipe, and the sipe width is provided at both ends of the sipe in the longitudinal direction. In a pneumatic tire provided with bent portions that are uneven in the direction, the flat portion of the sipe is formed so that a part thereof reaches an end portion in the length direction of the sipe.

  Thereby, since the rigidity of a block and / or a rib is ensured by the bending part of a sipe, the fall of the block at the time of a new article is suppressed. In addition, since the bent part is provided at both ends of the sipe in the longitudinal direction and the flat part is provided in the central part in the longitudinal direction of the sipe, the rigidity of the block or rib by the bent part becomes excessively high as wear progresses. There is no. Further, the flat portion facilitates removal of the mold during vulcanization molding. At that time, since a part of the flat part is formed so as to reach the end in the length direction of the sipe, even if bent portions are provided at both ends in the length direction of the sipe, the mold can be easily removed. There is no reduction.

  According to the present invention, since the collapse of the block at the time of a new article can be suppressed, it is possible to improve uneven wear resistance and steering stability. In addition, since the rigidity of the block and the rib due to the bent portion does not become excessively high as wear progresses, sufficient braking performance can be obtained on wet road surfaces and on-ice road surfaces. Furthermore, since the mold can be easily removed during vulcanization molding, it is possible to effectively prevent damage to the blocks and ribs when the mold is removed. At that time, even if bent portions are provided at both ends in the longitudinal direction of the sipe, the ease of removal of the mold is not reduced, which is extremely advantageous for preventing damage to the block when the mold is pulled out.

Partial front sectional view of the pneumatic tire showing the first embodiment of the present invention Block perspective view Simplified schematic perspective view Block top view Block end view Schematic left side, schematic front and schematic right side view Schematic left side, schematic front, and schematic right side view of a sipe showing a second embodiment of the present invention Schematic left side, schematic front, and schematic right side view of a sipe showing a third embodiment of the present invention The schematic left side, schematic front, and schematic right side view of the sipe showing the fourth embodiment of the present invention Simplified schematic left side, schematic front and schematic right side view of a sipe showing a fifth embodiment of the present invention Simplified schematic left side, schematic front, and schematic right side view of a sipe showing a sixth embodiment of the present invention The perspective view of the block which shows the 7th Embodiment of this invention Simplified schematic perspective view Schematic left side, schematic front and schematic right side view The schematic left side, schematic front, and schematic right side view of the sipe showing the eighth embodiment of the present invention Simplified schematic left side, schematic front, and schematic right side view of a sipe showing a ninth embodiment of the present invention The schematic left side, schematic front, and schematic right side view of the sipe showing the tenth embodiment of the present invention Schematic left side, schematic front, and schematic right side view of a sipe showing an eleventh embodiment of the present invention Schematic left side, schematic front, and schematic right side view of a sipe showing a twelfth embodiment of the present invention Schematic perspective view of a sipe showing a first conventional example Schematic left side, schematic front and schematic right side view Schematic perspective view of a sipe showing a second conventional example Sipes schematic left side, schematic front, schematic right side, and schematic plan view Schematic perspective view of a sipe showing a third conventional example Sipes schematic left side, schematic front, schematic right side, and schematic plan view Diagram showing test results

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 6. FIG. 3 shows the shape of the sipe on three-dimensional coordinates, and the shading applied to the sipe is a shadow for clarifying the three-dimensional shape (FIG. 13 of another embodiment, diagram of a conventional example). 20, 20 and 23 are the same). Moreover, although the sipe is illustrated in a pseudo-planar shape, it is actually a narrow groove formed with a predetermined width.

  The pneumatic tire shown in the figure includes a tread portion 1 formed on the tire outer peripheral surface side, a pair of sidewall portions 2 formed on both sides in the tire width direction, and a pair of bead portions formed on both sides in the tire width direction. 3 and a shoulder portion 4 formed between the tread portion 1 and the sidewall portion 2.

  The pneumatic tire includes an inner liner 5 disposed on the inner surface of the tire, a carcass member 6 disposed on the outer side of the inner liner 5, a pair of bead members 7 disposed on both sides in the tire width direction, and the carcass member 6 The belt 8 is arranged on the outer side of the tire, the tread member 9 is arranged on the tire outer peripheral surface side, and the pair of sidewall members 10 are arranged on both tire side surfaces.

  The inner liner 5 is made of a sheet-like rubber having low gas permeability, and is disposed on the inner peripheral surface side of the carcass member 6.

  The carcass member 6 is formed by covering a plurality of reinforcing cords 6a with sheet-like rubber, and is folded back toward the sidewall portion 2 from the inner side to the outer side in the tire width direction so as to enclose the bead member at both ends.

  The bead member 7 includes a bead core 7a formed by bundling wires such as metal wires and a bead filler 7b formed of rubber having a substantially triangular cross section. The bead filler 7b is disposed on the outer peripheral side of the bead core 7a.

  The belt 8 is formed by coating a belt cord made of steel, high-strength fiber, or the like with a sheet-like rubber, and is disposed on the outer peripheral surface side of the carcass member 6.

  The tread member 9 is made of rubber formed by extrusion molding, and is disposed so as to cover the center side in the width direction of the carcass member 6 and the outer peripheral surface side of the belt 8.

  The sidewall member 10 is made of rubber formed by extrusion molding and is disposed so as to cover both sides of the carcass member 6 in the tire width direction.

  The tread portion 1 of the pneumatic tire is formed with a plurality of grooves 1a extending in the tire circumferential direction and the tire width direction, and a plurality of blocks 11 defined by the grooves 1a. A plurality of sipes 12 extending in the direction are provided.

  The sipe 12 is formed by a narrow groove having a width of 0.4 mm to 1.5 mm, and both ends in the length direction (tire width direction) penetrate the both sides of the block 11 in the tire width direction. The sipe 12 is formed by a flat portion 13 provided at the center in the length direction and bent portions 14 provided at both ends in the length direction. The bent portion 14 is formed in the width direction of the sipe 12 (tires). It is bent so as to be uneven in the circumferential direction). That is, the sipe 12 has an end surface in the direction of arrows AA in FIG. 4 (one end surface in the tire width direction of the block 11 shown in FIG. 5A) and an end surface in the direction of arrows CC in FIG. 5 (FIG. 5C). The other end surface of the block 11 shown in the tire width direction is bent so as to be uneven in the width direction of the sipe 12 (the tire circumferential direction), and the end surface in the direction of the arrow BB (the block shown in FIG. 5B). 11 in the tire width direction central end face) is formed in a straight line. The bent portion 14 is formed in a three-dimensional shape by a plurality of triangular pyramidal surface portions, and is bent so as to form a linear waveform with respect to the depth direction (tire radial direction) of the sipe 12. In this case, a part of the plane portion 13 extends between the triangular pyramidal surface portions, and the extension portion 13a is formed so that the tapered tip reaches the end portion in the length direction of the sipe 12. Has been.

  According to the pneumatic tire of the present embodiment, the braking performance on wet road surfaces and on-ice road surfaces can be improved by the edge effect and drainage effect of the sipe 12. Moreover, since the rigidity of the block 11 can be ensured by the bent portion 14 of the sipe 12, the block 11 can be prevented from falling down when it is new, and uneven wear resistance and steering stability can be improved. . Further, since the bent portions 14 are provided only at both ends in the longitudinal direction of the sipe 12, and the flat portion 13 is provided in the central portion in the longitudinal direction of the sipe 12, the block rigidity due to the bent portion 14 is excessively high when wear progresses. Therefore, the braking performance on the wet road surface and the ice surface can be sufficiently obtained. Further, since the mold can be easily removed during the vulcanization molding by the flat portion 13, damage to the block 11 when the mold is removed can be effectively prevented. In this case, since part of the flat portion 13 (extending portion 13a) is formed so as to reach both ends in the length direction of the sipe 12, even if the bent portions 14 are provided at both ends in the length direction of the sipe 12, There is an advantage that the ease of removal of the mold is not lowered.

  FIG. 7 shows a second embodiment of the present invention, in which bent portions 15 that are longer in the length direction of the sipe 12 than the bent portions 14 of the first embodiment are provided at both ends in the length direction of the sipe 12. It is a thing. Thereby, the rigidity by the bending part 15 can be improved compared with 1st Embodiment.

  FIG. 8 shows a third embodiment of the present invention, in which bent portions 16 that are longer in the length direction of the sipe 12 than the bent portions 15 of the second embodiment are provided at both ends in the length direction of the sipe 12. In addition, the bent portions 16 at both ends in the length direction of the sipe 12 are formed so as to contact each other at the center portion in the length direction of the sipe 12. Thereby, the rigidity by the bending part 16 can be improved compared with 2nd Embodiment.

  FIG. 9 shows a fourth embodiment of the present invention. The lengths b1 and b2 of the sipe 12 in the length direction are one end side in the depth direction of the sipe 12 (the tire). A bent portion 17 that gradually decreases from the radially outer side to the other end side (inner tire radial direction) is provided. In other words, the bent portion 17 is formed such that an inclination angle θ formed by a straight line connecting the base ends (a chain line in the drawing) with respect to the length direction of the sipe 12 is greater than 90 °. Thereby, the rigidity by the bent portion 17 can be lowered as the wear of the block 11 progresses.

  FIG. 10 shows a fifth embodiment of the present invention, in which bent portions 18 having a smaller number than the bent portions 14 of the first embodiment are provided at both ends in the longitudinal direction of the sipe 12. Thereby, compared with 1st Embodiment, the rigidity by the bending part 15 can be made low.

  FIG. 11 shows a sixth embodiment of the present invention. Bending portions 19 and 20 having different sizes a1 and a2 in the width direction of the sipe 12 on one end side and the other end side of the sipe 12 in the width direction. Is provided. Thereby, the rigidity of the longitudinal direction one end side and the other end side of the sipe 12 can be made different.

  12 to 14 show a seventh embodiment of the present invention. The bent portion 21 of the present embodiment is formed in a three-dimensional shape by a plurality of spherical portions, and is bent so as to form a curved waveform with respect to the depth direction of the sipe 12 (tire radial direction). In this case, the tip of the extended portion 13 a of the flat surface portion 13 is formed between the spherical portions so as to reach the end portion of the sipe 12 in the length direction. In the present embodiment, since the bent portion 21 is formed to have a curved waveform by a plurality of spherical portions, the effect of restricting the collapse of the block 11 can be enhanced, and even if the bent portion 21 is made small, high rigidity is achieved. Can be obtained.

  FIG. 15 shows an eighth embodiment of the present invention, in which bent portions 22 that are longer in the length direction of the sipe 12 than the bent portions 21 of the seventh embodiment are provided at both ends in the length direction of the sipe 12. It is a thing. Thereby, the rigidity by the bending part 22 can be improved compared with 7th Embodiment.

  FIG. 16 shows a ninth embodiment of the present invention. Bending portions 23 and 24 having different lengths b1 and b2 in the length direction of the sipe 12 are provided on one end side and the other end side in the length direction of the sipe 12 respectively. It is provided. Thereby, the rigidity of the longitudinal direction one end side and the other end side of the sipe 12 can be made different.

  FIG. 17 shows a tenth embodiment of the present invention. Bending portions 25 and 26 having different lengths b1 and b2 in the length direction of the sipe 12 are provided on one end side and the other end side in the length direction of the sipe 12 respectively. In addition, the bent portions 25 and 26 at both ends in the length direction of the sipe 12 are formed so as to be in contact with each other at the center portion in the length direction of the sipe 12. Thereby, while the rigidity of the longitudinal direction one end side and the other end side of the sipe 12 can be made different, the rigidity by the bending parts 25 and 26 can be improved.

  FIG. 18 shows an eleventh embodiment of the present invention. The concavo-convex sizes a1 and a2 in the width direction of the sipe 12 at both ends in the lengthwise direction of the sipe 12 rather than the bent portion 21 of the seventh embodiment. Is provided with a small bent portion 27. Thereby, compared with 7th Embodiment, the rigidity by the bending part 27 can be made low.

  FIG. 19 shows a twelfth embodiment of the present invention. Bending portions 28 and 29 having different concavo-convex sizes a1 and a2 in the width direction of the sipe 12 on one end side and the other end side in the length direction of the sipe 12. Is provided. Thereby, the rigidity of the longitudinal direction one end side and the other end side of the sipe 12 can be made different.

  In the above embodiment, the both ends of the sipe in the length direction are opened on the side surface of the block. However, the present embodiment is also applicable to a case where at least one end in the length direction of the sipe is not opened on the side surface of the block. The invention can be applied.

  In the above embodiment, the block provided with the sipe of the present invention is shown. However, the sipe of the present invention may be provided only on the block and the rib, or the rib. Here, for Examples 1 to 12 and Conventional Examples 1 to 3 of the present invention, tests on braking performance on ice, turning performance on ice, resistance to uneven wear, ease of removal of the mold during vulcanization molding, The result shown in FIG. 26 was obtained.

  Example 1 includes the first embodiment, Example 2 includes the second embodiment, Example 3 includes the third embodiment, and Example 4 includes the fourth embodiment and examples. 5 for the fifth embodiment, Example 6 for the sixth embodiment, Example 7 for the seventh embodiment, Example 8 for the eighth embodiment and Example 9. Are the ninth embodiment, the tenth embodiment is the tenth embodiment, the eleventh embodiment is the eleventh embodiment, and the twelfth embodiment is the twelfth embodiment.

  In Conventional Example 1, as shown in FIGS. 20 and 21, a sipe 30 having only a flat portion 31 was used. As shown in FIGS. 22 and 23, the conventional example 2 includes only a bent portion 32 that bends in a waveform with respect to the length direction of the sipe 30, and the bent portion 32 has one end side in the depth direction of the sipe 30 and the other. What was formed in the three-dimensional shape which makes symmetrical shape in the end side was used. In Conventional Example 3, as shown in FIGS. 24 and 25, the center portion in the length direction of the sipe 30 is formed by the flat portion 33, and both end portions in the length direction of the sipe 30 are each formed only by the bent portions 34. Was used.

  In this test, tires having a tire size of 205 / 65R15 and an air pressure of 200 kPa were mounted on a normal passenger car having a displacement of 2000 cc.

  In the on-ice braking performance test, the reciprocal of the distance from when braking is started at a speed of 40 km / h on the icy road surface until the vehicle stops is indexed, and Conventional Example 1 is taken as 100 and Conventional Examples 2-3 and Examples 1-12. Evaluated. In this case, the larger the index value, the more superior.

  In the test of turning performance on ice, a test vehicle equipped with pneumatic tires was used to measure the average value of five lap times of turning on a circle with a radius of 30 m on an icy road, and the reciprocal number was indexed. Conventional examples 2-3 and Examples 1-12 were evaluated as 100. In this case, the larger the index value, the more superior.

  In the uneven wear resistance test, after running 10,000 km of the specified course on the test course, the reciprocal of the evaluation result based on the appearance of the degree of uneven wear (uneven wear amount and size) in the tread after running was calculated. The results were indexed, and Conventional Examples 1 to 100 were evaluated as Conventional Examples 2-3 and Examples 1-12. In this case, the larger the index value, the more superior.

  In the test of detachability of the mold at the time of vulcanization molding, the reciprocal of the occurrence rate of the mold detachment failure of the tire after vulcanization is indexed, and Conventional Example 1 is taken as 100 and Conventional Examples 2-3 and Examples 1-12. Evaluated. In this case, the larger the index value, the more superior.

  As a result of the test, Examples 1 to 12 were superior to Conventional Example 1 in braking performance on ice, on-ice turning performance and uneven wear resistance, and superior in conventional molds 2 and 3 in the ease of mold removal. Obtained.

  DESCRIPTION OF SYMBOLS 1 ... Tread part, 11 ... Block, 12 ... Sipe, 13 ... Plane part, 13a ... Extension part, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 ... bent portions.

Claims (7)

The tread block and / or rib has a sipe, a flat portion is provided at the center in the length direction of the sipe, and bent portions that are uneven in the width direction of the sipe are provided at both ends in the length direction of the sipe. In pneumatic tires,
A pneumatic tire characterized in that the flat portion of the sipe is formed so that a part thereof reaches an end portion in the length direction of the sipe. 2. The pneumatic tire according to claim 1, wherein the bent portion is formed so that a length of a sipe in a length direction gradually decreases from an outer side in a tire radial direction toward an inner side. The bent part at one end in the length direction of the sipe and the bent part at the other end in the length direction are formed so that the lengths in the length direction of the sipe are different from each other. Pneumatic tire. The bent portion at one end in the length direction of the sipe and the bent portion at the other end in the length direction are formed so that the size of the unevenness in the width direction of the sipe is different from each other. 3. The pneumatic tire according to 3. The bent part on one end side in the sipe length direction and the bent part on the other end side in the length direction are formed so as to be in contact with each other on the center side in the sipe length direction. Pneumatic tires. The pneumatic tire according to claim 1, 2, 3, 4 or 5, wherein the bent portion is formed so as to have a linear waveform with respect to a sipe depth direction. The pneumatic tire according to claim 1, 2, 3, 4 or 5, wherein the bent portion is formed to have a curved waveform with respect to a sipe depth direction.