JP2017105384A - Pneumatic tire and method for manufacturing the same - Google Patents

Abstract

A pumping noise is suppressed and drainage is improved. A tread portion includes a plurality of blocks 4 formed by a main groove 2 extending in a tire circumferential direction and a lateral groove 3 extending in a tire width direction. The block 4 includes a closing groove 5 that does not open in the main groove 2 and the lateral groove 3, and a recess 6 that is formed on a side surface of the lateral groove 3 and communicates with the closing groove 5. A communication path 7 that communicates between the lateral grooves 3 on both sides of the block 4 is formed by the closing groove 5 and the recess 6. [Selection] Figure 1

Description

  The present invention relates to a pneumatic tire and a method for manufacturing the same.

  Conventionally, as a pneumatic tire, a tire in which both ends of a sipe are closed in a block and a through hole that penetrates the block and the sipe and is open to a lateral groove at both ends is known (for example, Patent Documents). 1).

  However, the conventional pneumatic tire is configured to generate an air flow in the through hole in order to increase the amount of moisture that can be sucked into the sipe. That is, this configuration is not intended to enhance drainage performance in the lateral groove or suppress the generation of pumping noise.

JP 2008-1260 A

  An object of the present invention is to provide a pneumatic tire capable of suppressing pumping noise and improving drainage and a method for manufacturing the same.

As a means for solving the above problems, the present invention provides:
In the tread portion, a pneumatic tire having a plurality of blocks formed by a main groove extending in the tire circumferential direction and a lateral groove extending in the tire width direction,
The block includes a closing groove that extends from the upper surface in the tire inner diameter direction without opening in the main groove and the lateral groove, and a concave portion that is formed on a side surface of the lateral groove and communicates with the closing groove,
Provided is a pneumatic tire in which a communication path that communicates between lateral grooves on both sides of the block is formed by the closing groove and the recess.

  With this configuration, when traveling on a wet road surface, the water in the lateral groove on the traveling direction R side passes through the communication path and flows into the lateral groove on the traveling direction L side. That is, the water in the lateral groove on the traveling direction R side flows into the concave portion formed on the side surface, passes through the closing groove, and then the lateral groove on the traveling direction L side from the concave portion on the side surface constituting the lateral groove on the traveling direction L side. It flows out into. Therefore, drainage can be improved as compared with a block in which no communication path is formed in the block. Further, when traveling on a dry road surface, the air in the lateral groove on the traveling direction R side is compressed, but can escape to the lateral groove on the traveling direction L side through the communication path. Therefore, the air in the lateral groove on the traveling direction R side is not compressed, and it is possible to reliably prevent the generation of pumping noise when leaving the road surface.

  It is preferable that the opening area of the side surface of the concave portion forming the lateral groove is larger than the opening area of the communication portion with the closing groove.

  With this configuration, the concave portion on the traveling direction R side serves as a so-called funnel, and it becomes easy to take in water in the lateral groove. In addition, the concave portion relaxes the rapid change in the cross section of the flow path between the inflow of water into the closed groove and the outflow of water from the closed groove, and suppresses the phenomenon of water separation from the flow path surface, A smooth flow can be realized.

  It is preferable that the closing groove has an extended portion whose cross-sectional area gradually increases from the traveling direction R side in the tire circumferential direction toward the traveling direction L side.

  With this configuration, the drainage can be further enhanced.

  In this case, the groove bottom of the closing groove may be inclined so as to gradually become deeper from the lateral groove on the traveling direction R side toward the lateral groove on the traveling direction L side.

Further, the present invention provides a means for solving the above-described problems,
In the tread portion, a pneumatic tire having a plurality of blocks formed by a main groove extending in the tire circumferential direction and a lateral groove extending in the tire width direction,
A first mold part for forming a closed groove in the block; and a second mold part for forming a horizontal groove and a recess in the block. After the vulcanization molding, the first mold part is detached from the closed groove. Then, a method for manufacturing a pneumatic tire is provided in which the second mold part is detached from the lateral groove.

  According to the present invention, the block is formed with the communication path that connects the lateral grooves on both sides in the tire circumferential direction, so that when traveling on a wet road surface, the water in the lateral groove on the traveling direction R side is moved in the traveling direction. It can be made to flow out to the lateral groove on the L side, and drainage performance can be improved. Further, when traveling on a dry road surface, the air in the lateral groove on the traveling direction R side can flow to the lateral groove on the traveling direction L side, and generation of pumping noise can be suppressed.

It is a partial expanded view of the tread part of the pneumatic tire concerning this embodiment. (A) is a top view of the block which concerns on 1st Embodiment, (b) is the AA sectional view taken on the line. (A) is the top view of the block which concerns on 2nd Embodiment, (b) is the AA sectional view taken on the line, (c) is the BB sectional drawing. (A) is a top view of the block which concerns on 3rd Embodiment, (b) is the AA sectional view taken on the line. (A) is a top view of the block which concerns on 4th Embodiment, (b) is the AA sectional view taken on the line. (A) Sectional drawing of the block which concerns on other embodiment, (b) is the side view. (A) Sectional drawing of the block which concerns on other embodiment, (b) is the side view. It is sectional drawing of the block which concerns on other embodiment.

  Embodiments according to the present invention will be described below with reference to the accompanying drawings. In addition, the following description is only illustrations essentially and does not intend restrict | limiting this invention, its application thing, or its use. Further, the drawings are schematic, and the ratio of each dimension is different from the actual one.

  FIG. 1 is a partial development view of a tread portion 1 of a pneumatic tire according to the present embodiment. Although not shown, this pneumatic tire has a structure in which a carcass is stretched between a pair of bead cores, reinforced by a belt wound around an outer peripheral side of an intermediate portion of the carcass, and a tread portion 1 is provided in the tire outer diameter direction. Yes.

  A plurality of blocks 4 are formed in the tread portion 1 by a plurality of main grooves 2 extending in the tire circumferential direction and a plurality of lateral grooves 3 extending in the tire width direction. As shown in FIGS. 2 to 5, a communication passage 7 is formed in each block 4 by a closing groove 5 and a pair of recesses 6. The communication passage 7 can employ various configurations described below.

(First embodiment)
The configuration of the communication path 7 according to the first embodiment is as shown in FIGS.
The closing groove 5 is formed at the center position of the block 4 in the tire width direction, has a rectangular shape elongated in the tire circumferential direction, and extends in the tire inner diameter direction. The depth of the closing groove 5 is set to be equal to or less than the block height.

  The recesses 6 are opened on both side surfaces formed by the lateral grooves 3 on both sides of the block 4. That is, the recessed part 6 consists of the 1st recessed part 8 opened to the side surface by the side of the tire advancing direction R of the block 4, and the 2nd recessed part 9 opened to the side surface by the side of the tire advancing direction L. Each concave portion 6 has a substantially hemispherical shape, and a closing groove 5 communicates with the central portion thereof. The formation position of each recess 6 is a position where the circular opening on the side face just contacts the groove bottom of the lateral groove 3.

  The pneumatic tire provided with the block 4 having the communication path 7 according to the first embodiment can be manufactured as follows. That is, a mold having a first mold part 10 for forming the closing groove 5 and a second mold part 11 for forming the recess 6 opening in the groove together with the lateral groove 3 is used as the mold. To do. The first mold part 10 is made of a plate-like body. The second mold part 11 includes a ridge part forming the lateral groove 3 and a hemispherical protrusion projecting therefrom, and a convex part 12 having a flat surface with the tip part contacting the end part of the first mold part 10. Prepare.

  When the mold is opened after vulcanization molding, the first mold part 10 is first moved, and then the second mold part 11 is moved. Thereby, although both ends of the first mold part 10 and the flat surface of the convex part 12 of the second mold part 11 are in contact with each other, the mold can be opened. That is, when the second mold part 11 is moved, since the first mold part 10 has already been moved, the rubber of the tire component part pressed by the convex portion 12 of the second mold part 11 is changed to the first mold part 10. One mold part 10 can be elastically deformed into a space formed by movement. In this case, it is the substantially hemispherical convex part 12 that is pressed, and the deformation amount of the rubber can be suppressed. Accordingly, there is no occurrence of problems such as cutting in the rubber.

  In the pneumatic tire formed in this way, the opening area of the first recess 8 opened on the side surface on the traveling direction R side is large. For this reason, when traveling on a wet road surface, the water that has entered the lateral groove 3 on the traveling direction R side by the first recess 8 can be collected smoothly. The first recess 8 is formed so that the cross-sectional area of the channel gradually decreases toward the closing groove 5. For this reason, the water collected in the first recess 8 can smoothly flow toward the closing groove 5 without causing a peeling phenomenon with the inner surface of the first recess 8. The water passing through the closed groove 5 and reaching the second recess 9 gradually flows into the lateral groove 3 on the traveling direction L side without receiving flow resistance because the flow passage cross-sectional area there is gradually widened. Is done.

  Further, when traveling on a dry road surface, the blocks 4 on both sides of the lateral groove 3 on the traveling direction R side are grounded and pushed in, so that the air in the lateral groove 3 on the traveling direction R side is compressed. At this time, the compressed air flows into the lateral groove 3 on the traveling direction L side through the communication path 7. Therefore, even if the block 4 is separated from the road surface and the lateral groove 3 on the traveling direction R side is opened to the atmosphere, there is no compressed air in the lateral groove 3 on the traveling direction R side, and therefore pumping noise is generated. It does not occur.

(Second Embodiment)
The configuration of the communication path 7 according to the second embodiment is as shown in FIG.
The opening shape of the closing groove 5 on the upper surface of the block 4 is the same as that of the first embodiment, but the internal flow path portion is formed so that the cross-sectional area is larger than the upper surface opening of the block 4. Is different. That is, a communication region 13 is formed at the groove bottom portion of the closing groove 5 so as to be widened by a region having a semicircular cross section on both sides rather than the width dimension of the upper opening. In addition, the traveling direction R side and the traveling direction L side of both end portions of the communication region 13 are extended portions 14. The extension portion 14 gradually decreases in opening cross-sectional area toward the recess 6, and is formed in a hollow shape that communicates with the central portion of the recess 6.

  In order to form the closed groove 5 having the above-described configuration, the first mold part 10 has a plate-like shape and a cylindrical portion 15 bulged in a semicircular cross section on both sides so that the lower end portion can form the communication region 13. It consists of what you have. At both ends of the columnar portion 15, projecting portions 16 that gradually decrease in outer diameter are formed. In vulcanization molding, the protrusion 16 of the first mold part 10 and the convex part 12 of the second mold part 11 are in contact with each other. When opening the mold, when the first mold part 10 is first moved, the rubber corresponding to the protrusion 16 is deformed, but the protrusion dimension of the protrusion itself is not so large, and the occupied volume is also large. Since it is not so large, there is no worry of cracks in the rubber. Further, since the protruding portion 16 is provided on the cylindrical portion 15 having a larger outer diameter, the protruding portion 16 has sufficient strength, and causes a problem such as deformation of the protruding portion 16 when the first mold part 10 is moved. There is nothing.

  In the pneumatic tire provided with the communication path 7 having the above-described configuration, since the communication portion of the closing groove 5 and the recess 6 is formed by the protruding portion 16, as described above, there is a problem such as a crack when the mold is opened. It does not occur easily and has sufficient strength. Accordingly, the block 4 is not easily damaged even when used over a long period of time, and when traveling on a wet road surface, the cross section of the communication path 7 can be sufficiently widened. It is possible to smoothly drain water into the lateral groove 3 on the traveling direction L side.

(Third embodiment)
The configuration of the communication path 7 according to the third embodiment is as shown in FIG.
The closing groove 5 is the same as in the first and second embodiments in that the central portion of the upper surface of the block 4 extends in the tire circumferential direction, but is different in that it is divided into two in the longitudinal direction. That is, a first closing groove 17 and a second closing groove 18 extending in the tire circumferential direction are formed at the center of the upper surface of the block 4. The extension portions 14 are formed at both ends of the first closing groove 17 and the second closing groove 18 as in the second embodiment. The first closing groove 17 and the second closing groove 18 are communicated with each other by the extension portions 14. The extension 14 of the second closing groove 18 communicates with the first recess 8, and the extension 14 of the first closing groove 17 communicates with the second recess 9.

  In order to form the closed groove 5 having the above-described configuration, the first mold part 10 is composed of two parts, a first plate-like body 19 and a second plate-like body 20. In this case, the 1st plate-shaped body 19 and the 2nd plate-shaped body 20 can be set as the substantially the same structure except the 1st metal mold | die component 10 which concerns on the said 2nd Embodiment, and the dimension of a longitudinal direction. The first plate body 19 and the second plate body 20 may be moved with a time difference when the mold is opened. Thereby, when moving the first plate-like body 19 and the second plate-like body 20 when the mold is opened, there is no fear of causing problems such as cracks in the rubber due to the movement of the protruding portion 16. Further, the protrusion itself is not deformed.

  In the pneumatic tire provided with the communication path 7 having the above-described configuration, the strength of the block itself can be improved by separating the closing groove 5 in addition to the same effects as those of the second embodiment. Therefore, even if it is used for a long time, it is hard to be damaged.

(Fourth embodiment)
The configuration of the communication path 7 according to the fourth embodiment is as shown in FIG.
The closing groove 5 is formed by juxtaposing the tire extending in the tire width direction in the tire circumferential direction. Here, the closing grooves 5 are arranged in parallel at four places, and the closing grooves 5 are communicated with each other by the extension portion 14 as in the second or third embodiment. That is, the extension part 14 which becomes small in opening cross-sectional area gradually extends from both ends of the closing groove 5 from the center of the lower end part, and communicates with the extension part 14 extending from the adjacent closing groove 5.

  In order to form the closed groove 5 having the above-described configuration, the first mold part 10 includes first to fourth plate-like bodies 21 to 24. On both surfaces of each plate-like body 21 to 24, a protrusion 16 is formed at the center of the lower end. And these plate-like bodies 21-24 should just move a thing which adjoins at the time of mold opening, providing a time difference. For example, after the first and third plate-like bodies 21 and 23 are moved, the second and fourth plate-like bodies 22 and 24 may be moved. Thereby, there is no fear of causing a problem such as a crack in the rubber by the movement of the protruding portion 16, and the protruding portion 16 itself is not deformed.

  In the pneumatic tire provided with the communication passage 7 having the above-described configuration, in addition to the same effects as those of the second embodiment, a large number of the closing grooves 5 are formed so that the water absorption when the surface of the block 4 is grounded when traveling on a wet road surface. The power can be improved.

(Other embodiments)
In addition, this invention is not limited to the structure described in the said embodiment, A various change is possible.

  In the above embodiment, the shape of the concave portion 6 opened on the side surface of the block 4 is circular. However, the present invention is not limited to this, and various forms can be adopted as shown in FIGS. It is not limited to.

  In FIG. 6, the opening shape of the concave portion 6 on the side surface of the block 4 is a triangle whose width dimension gradually narrows toward the upper side. The concave portion 6 has a triangular base that is flush with the bottom of the closing groove 5, and the opening shape is displaced so that the upward protruding portion gradually becomes lower toward the closing groove 5.

  In FIG. 7, the opening shape of the recess 6 on the side surface of the block 4 is a semicircular shape that bulges upward in an arc shape. The concave portion 6 has a semicircular diameter portion flush with the bottom of the closing groove 5, and the opening shape is displaced so that a portion protruding upward gradually becomes lower toward the closing groove 5.

  In the above-described embodiment, the communication path 7 is formed in parallel to the upper surface of the block 4, but may be formed to be inclined as shown in FIG. By forming the communication path 7 at an angle, the water that has entered the communication path 7 can be easily discharged.

DESCRIPTION OF SYMBOLS 1 ... Tread part 2 ... Main groove 3 ... Horizontal groove 4 ... Block 5 ... Closure groove 6 ... Recess 7 ... Communication path 8 ... 1st recessed part 9 ... 2nd recessed part 10 ... 1st metal mold part 11 ... 2nd metal mold part 12 ... Projection 13 ... Communication region 14 ... Extension part 15 ... Cylindrical part 16 ... Protrusion 17 ... First closing groove 18 ... Second closing groove 19 ... First plate-like body 20 ... Second plate-like body 21 ... First plate -Like body 22 ... second plate-like body 23 ... third plate-like body 24 ... fourth plate-like body

Claims (5)

In the tread portion, a pneumatic tire having a plurality of blocks formed by a main groove extending in the tire circumferential direction and a lateral groove extending in the tire width direction,
The block includes a closing groove that extends from the upper surface in the tire inner diameter direction without opening in the main groove and the lateral groove, and a concave portion that is formed on a side surface of the lateral groove and communicates with the closing groove,
The pneumatic tire according to claim 1, wherein a communication path that communicates between the lateral grooves on both sides of the block is formed by the closed groove and the recess.   2. The pneumatic tire according to claim 1, wherein an opening area of a side surface of the concave portion forming the lateral groove is larger than an opening area of a communication portion with the closing groove.   3. The pneumatic tire according to claim 1, wherein the closing groove has an extended portion whose cross-sectional area gradually increases from the traveling direction R side in the tire circumferential direction toward the traveling direction L side.   4. The pneumatic tire according to claim 3, wherein a groove bottom of the closing groove is inclined so as to gradually become deeper from a lateral groove on the traveling direction R side toward a lateral groove on the traveling direction L side. In the tread portion, a pneumatic tire having a plurality of blocks formed by a main groove extending in the tire circumferential direction and a lateral groove extending in the tire width direction,
A first mold part for forming a closed groove in the block; and a second mold part for forming a horizontal groove and a recess in the block. After the vulcanization molding, the first mold part is detached from the closed groove. Then, the second mold part is removed from the lateral groove.

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