JP5289157B2 - Pneumatic tire - Google Patents

Description

  The present invention includes a belt layer including a steel cord disposed obliquely with respect to the tire circumferential direction, and a belt reinforcing layer disposed on the outer side in the tire radial direction from the belt layer, and a price tear residual cornering force is provided. The present invention relates to a generated pneumatic tire.

  A road on which a vehicle such as a passenger car travels normally has a slope (cant) that decreases from the center of the road toward the road shoulder in order to drain rainwater and the like naturally onto the road shoulder.

  That is, in the case of left-hand traffic, the road is formed so as to become lower from the right to the left with respect to the traveling direction of the vehicle. On the other hand, in the case of right-hand traffic, the situation is reversed, and the road is formed so as to become lower from the left to the right with respect to the traveling direction.

  In order to ensure the straightness of the vehicle even when traveling on such a road, a method using a residual cornering force (RCF) of a pneumatic tire is widely used. Specifically, when pneumatic tires are installed on the left and right wheels of a vehicle, a price tear residual cornering force (PRCF) that generates force in the same direction is generated, and the straightness of the vehicle on a canted road is improved. Secured.

  As a method for adjusting the direction and size of PRCF generation, a method of using both a tread pattern and a belt layer cord arrangement direction is generally used (for example, Patent Document 1).

JP 2008-213636 A (page 5, FIG. 1-2)

  However, the conventional PRCF adjustment method described above has the following problems. That is, since the adjustment of the direction and size of PRCF is accompanied by a change in the tread pattern, it is necessary to change the vulcanization mold of the pneumatic tire, which increases the time and cost.

  In recent years, there has been a demand for pneumatic tires to generate a larger PRCF than ever before. In other words, there is a concern that the conventional method cannot generate sufficient PRCF to meet such requirements.

  Therefore, an object of the present invention is to provide a pneumatic tire that generates a necessary and sufficient price tear residual cornering force only by an internal structure such as a belt layer without depending on a tread pattern.

  In order to solve the above-described problems, the present invention has the following features. First, the first feature of the present invention is that a belt layer (belt layer 30) in which a plurality of cords (steel cords 32 and 37) disposed obliquely with respect to the tire circumferential direction are covered with rubber, and the belt layer A belt reinforcement layer (belt reinforcement layer 100) disposed on the outer side in the tire radial direction, the belt reinforcement layer including a cap portion (cap portions 110 and 120) covering the entire belt layer, and the belt A pneumatic tire (pneumatic tire 10) having a pair of layer portions (layer portions 210, 220) covering both end portions (end portions 30a, 30b) in the tread width direction of the layer, wherein the pair of layer portions are The width of one of the layer portions is different from the width of the other layer portion and from the tire equator line (tire equator line CL) passing through the center in the tread width direction of the pneumatic tire. The length from the tire equator line to the other end portion (end portion 120a) in the tread width direction of the cap portion is different from the length from the tire equator line to the one end portion (end portion 110a) in the tread width direction of the top portion. And

  According to such a pneumatic tire, the width of one layer portion is different from the width of the other layer portion, the length from the tire equator line to one end of the cap portion, and the other portion of the cap portion from the tire equator line. The length to the end is different. Therefore, it is possible to generate a sufficient price tear residual cornering force due to the difference in the width of the layer portion and the difference in the position of the cap portion on the tire shoulder between the outer side when the vehicle is mounted and the inner side when the vehicle is mounted.

  The second feature of the present invention relates to the first feature of the present invention, and is provided on the stepping side (the end 37a side) of the cord that comes into contact with the road surface in advance as the road surface of the pneumatic tire rolls. The gist of the present invention is that the width of the layer portion positioned is wider than the width of the layer portion located on the kicking side (end portion 37b side) of the cord that comes into contact with the road surface later.

  A third feature of the present invention relates to the first or second feature of the present invention, and is located on a stepping side of the cord that contacts the road surface in advance as the road surface of the pneumatic tire rolls. The length of the cap portion from the tire equator line (length L1) is the length of the cap portion from the tire equator line (length L2) located on the side of the cord that contacts the road surface. The pneumatic tire according to claim 1 or 2, wherein the pneumatic tire is longer.

  A fourth feature of the present invention relates to the second or third feature of the present invention, wherein the belt layer is composed of a plurality of belts (first belt 31 and second belt 36), and the cord is the most The gist is that the cord is included in the belt (second belt 36) located on the outer side in the tire radial direction.

  A fifth feature of the present invention relates to the second to fourth features of the present invention, and is the width (width W1) of the layer portion located on the stepping side and the layer portion located on the kicking side. The difference with the width (width W2) is that it is 20% or more of the width of the layer portion located on the stepping side.

  A sixth feature of the present invention relates to the first to fifth features of the present invention, and is summarized in that a width of the layer portion located on the stepping side is 30 mm or more.

  According to the characteristics of the present invention, it is possible to provide a pneumatic tire that generates a necessary and sufficient price tear residual cornering force only by an internal structure such as a belt layer without depending on a tread pattern.

It is sectional drawing along the tread width direction and tire radial direction of the pneumatic tire 10 which concerns on embodiment of this invention. It is a figure showing the structure of belt layer 30 and belt reinforcement layer 100 of pneumatic tire 10 concerning the embodiment of the present invention. It is sectional drawing along the tread width direction of the belt reinforcement layer 100 which concerns on embodiment of this invention.

  Next, an embodiment of a pneumatic tire according to the present invention will be described with reference to the drawings. Specifically, (1) structure of pneumatic tire, (2) structure of belt layer and belt reinforcement layer, (3) detailed shape of belt reinforcement layer, (4) performance evaluation, (5) action and effect, and (6) Other embodiments will be described.

  In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones.

  Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(1) Structure of Pneumatic Tire FIG. 1 is a cross-sectional view of the pneumatic tire 10 along the tread width direction and the tire radial direction. As shown in FIG. 1, the pneumatic tire 10 includes a carcass 20 that forms a skeleton of the pneumatic tire 10, a belt layer 30 provided on the outer side in the tire radial direction of the carcass 20, and an end portion of the carcass 20. And a pair of annular beads 40. The pneumatic tire 10 assembled to the rim wheel is filled with an inert gas such as air or nitrogen gas.

  The belt layer 30 is constituted by a plurality of belts of a first belt 31 and a second belt 36. The belt layer 30 is provided in order to ensure predetermined rigidity and durability of the pneumatic tire 10, thereby generating a residual cornering force which will be described later. The second belt 36 is overlapped with the first belt 31 and provided on the outer side in the tire radial direction of the first belt 31. A cushion rubber 35 that absorbs the impact received by the pneumatic tire 10 is provided between the carcass 20 and both ends of the first belt 31.

  A belt reinforcing layer 100 is provided outside the belt layer 30 in the tire radial direction. The belt reinforcing layer 100 is provided to prevent the belt layer 30 from being lifted and the like to reinforce the belt layer 30 and to control a residual cornering force described later.

  The belt reinforcing layer 100 includes a cap portion and a pair of layer portions. Specifically, the belt reinforcing layer 100 includes a cap portion 110 and a cap portion 120 that cover the entire belt layer 30, and layer portions 210 and 220 that cover both ends of the belt layer 30 in the tread width direction. The cap part 110 and the layer part 210 are located outside in a state where the pneumatic tire 10 is mounted on the vehicle. On the other hand, the cap part 120 and the layer part 220 are located inside.

  When the tire equator line CL passing through the center in the tread width direction of the pneumatic tire 10 is used as a reference, the length from the tire equator line CL to the end portion 110a in the tread width direction of the cap portion 110 is from the tire equator line CL to the cap portion. 120 differs from the length to the end 120a in the tread width direction. In addition, the width of the layer part 210 constituting the pair of layer parts is different from the width of the layer part 220. The detailed shape of the belt reinforcing layer 100 will be described later.

(2) Structure of Belt Layer and Belt Reinforcement Layer Next, the structure of the belt layer 30 and the belt reinforcement layer 100 will be described. FIG. 2 is a diagram illustrating the structure of the belt layer 30 and the belt reinforcing layer 100 of the pneumatic tire 10.

(2.1) Belt layer 30
As shown in FIGS. 1 and 2, a belt layer 30 is provided on the outer side in the tire radial direction of the carcass 20. Cushion rubber 35 is provided between the carcass 20 and the end portions 30 a and 30 b of the belt layer 30.

  The belt layer 30 is composed of a first belt 31 and a second belt 36. The first belt 31 is obtained by coating a steel cord 32 with rubber, and the steel cord 32 is disposed obliquely with respect to the tire circumferential direction. Similarly, the second belt 36 is a steel cord 37 covered with rubber, and the steel cord 37 is disposed obliquely with respect to the tire circumferential direction. That is, both the first belt 31 and the second belt 36 have a plurality of cords.

  In the present embodiment, the steel cord 32 is disposed “upward to the right”. “Upward to the right” refers to a state where the cord is upwardly directed toward the tire rotation direction (traveling direction) in the drawing. On the other hand, the steel cord 37 is disposed “upward to the left”. “Upward to the left” refers to a state in which the cord is leftward with respect to the tire rotation direction (traveling direction).

  The arrangement direction of the steel cord 37 of the second belt 36, which is the belt provided on the outermost side in the tire radial direction, greatly affects the occurrence of residual cornering force. The end portion 37a of the steel cord 37 is positioned on the stepping side where the road surface of the pneumatic tire 10 comes into contact with the road surface first as the road surface rolls.

  On the other hand, the end portion 37b of the steel cord 37 is also located on the kicking side that contacts the road surface later than the end portion 37a. Since the steel cord 37 rises to the left in the tire rotation direction (traveling direction), when the pneumatic tire 10 rolls on the road surface, a price tear residual cornering force (hereinafter referred to as PRCF) to the left with respect to the traveling direction is generated. Occur. That is, the pneumatic tire 10 is provided for right-hand traffic that is canted so as to become lower as it goes from right to left with respect to the traveling direction.

(2.2) Belt reinforcing layer 100
The belt reinforcing layer 100 is provided on the outer side in the tire radial direction of the second belt 36 and covers the belt layer 30. In the present embodiment, two heads (not shown) are provided to send a corded reinforcing belt constituting a cap portion and a pair of layer portions onto the carcass 20 provided with the belt layer 30 when the pneumatic tire 10 is manufactured. The cap part and the pair of layer parts are wound around the second belt 36 in a spiral shape. That is, the cap portion and the pair of layer portions do not have a joint portion in the tire circumferential direction. Further, the cap portion and the pair of layer portions are wound around the belt reinforcing layer 100 as a unit.

  For this reason, a cap part is comprised by the cap part 110 sent out by one head, and the cap part 120 sent out by the other head. An end portion 110b of the cap portion 110 on the tire equator line CL side overlaps a part of an end portion 120b of the cap portion 120 on the tire equator line CL side. The end 120b is located on the outer side in the tire radial direction than the end 110b.

  The layer part 210 continues to the end part 110 a on the shoulder side of the cap part 110. The layer part 210 is provided inside the cap part 110 in the tire radial direction. In the present embodiment, first, a reinforcing belt corresponding to the layer part 210 fed from the head is wound around the second belt 36, and then folded in the reverse direction so that the reinforcing belt corresponding to the cap part 110 continues to the carcass 20. Then it is wound.

  Similarly, the layer part 220 continues to the end part 120 a on the shoulder side of the cap part 120. The layer part 220 is provided on the outer side in the tire radial direction of the cap part 120. In the present embodiment, first, a reinforcing belt corresponding to the cap portion 120 fed from the head is wound around the second belt 36, and then, the reinforcing belt corresponding to the layer portion 220 is folded back in the reverse direction. Wrapped around. The reinforcing belt in which the cap part 110 and the layer part 210 are integrated and the reinforcing belt in which the cap part 120 and the layer part 220 are integrated are wound around the second belt 36 in parallel at the same timing.

  The layer part 210 covers the end part 30 a of the belt layer 30 in the tread width direction, and the layer part 220 covers the end part 30 b of the belt layer 30 in the tread width direction.

(3) Detailed shape of belt reinforcing layer Next, the detailed shape of the belt reinforcing layer 100 will be described. FIG. 3 is a cross-sectional view of the belt reinforcing layer 100 along the tread width direction. As shown in FIG. 3, the end portion 110 a of the cap portion 110 is located on the shoulder side with respect to the end portion 30 a of the belt layer 30. Similarly, the end portion 120 a of the cap portion 120 is located on the shoulder side with respect to the end portion 30 b of the belt layer 30.

  The length from the tire equator line CL of the cap portion 110 located on the stepping side (the end portion 37a side) of the steel cord 37 that contacts the road surface first in accordance with the rolling of the road surface of the pneumatic tire 10 is defined as a length L1. To do. On the other hand, the length from the tire equator line CL of the cap portion 120 located on the kicking side (end portion 37b side) of the steel cord 37 is defined as a length L2. In the present embodiment, the length L1 is set longer than the length L2.

  Further, the width of the layer portion 210 located on the stepping side (the end portion 37a side) of the steel cord 37 that comes into contact with the road surface in advance as the road surface of the pneumatic tire 10 rolls is defined as a width W1. On the other hand, the width of the layer part 220 located on the kicking side (end part 37b side) of the steel cord 37 is defined as a width W2. In the present embodiment, the width W1 is set wider than the width W2. Furthermore, the difference between the width W1 and the width W2 is set to 20% or more of the width of the layer part 210 located on the stepping side of the steel cord 37, and the layer part 210 is 30 mm or more.

(4) Performance evaluation Next, the performance evaluation of the Example of the pneumatic tire 10 which has the structure mentioned above is demonstrated.

(4.1) Common Items Regarding performance evaluation, items common to the pneumatic tires according to the comparative example and the example are as follows.

・ Tire size: 215 / 45R17
・ Set internal pressure: 200 kpa
・ Load: 3.77kN
・ Rim used: 7JJ
Table 1 shows the specifications of the pneumatic tire according to the comparative example and the example.

  As shown in Table 1, in the comparative example, the width of the layer portion (width W1, width W2) and the length of the cap portion from the tire equator line CL (long) when the vehicle is mounted and the vehicle is mounted. The length L1 and the length L2) are the same. On the other hand, in the embodiment, the width of the layer portion (width W1, width W2) and the length of the cap portion from the tire equator line CL (length L1, length L2) are outside when the vehicle is mounted and when the vehicle is mounted. It is different on the inside.

Table 2 shows the set state of the belt reinforcing layer having the specifications shown in Table 1 and the lateral force component generated as the pneumatic tire rolls on the road surface with the specified load applied. . The unit of the lateral force component in Table 2 is N (Newton).

  In the comparative example and the example, the lateral force deviation (DC component of lateral force) shown in Table 2 is generated. The amount of lateral force deviation (LFD) generated varies depending on the rotation direction. Clockwise indicates the case where it is attached to the right wheel, and counterclockwise indicates the case where it is attached to the left wheel.

  Further, in the comparative example and the example, the price tear and the conicity shown in Table 2 are generated. The average value of the lateral force generated by the clockwise rotation and the lateral force generated by the counterclockwise rotation affects the PRCF.

  As shown in Table 2, in the example, the amount of PRCF generated in a specific direction can be increased or the amount generated can be adjusted only by the internal structure such as the belt layer.

(5) Action / Effect According to the pneumatic tire 10, the width of the layer part 210 is different from the width of the layer part 220, and the length L1 and the length L2 are different. Specifically, the width W1 of the layer portion 210 located on the stepping side (end portion 37a side) of the steel cord 37 is equal to the width W2 of the layer portion 220 located on the kicking side (end portion 37b side) of the steel cord 37. Is set wider than. Further, the length L1 from the tire equator line CL of the cap portion 110 located on the step-in side (end portion 37a side) of the steel cord 37 is a cap portion located on the kicking side (end portion 37b side) of the steel cord 37. 120 is set to be longer than the length L2 from the tire equator line CL.

  For this reason, it is sufficient due to the difference between the width of the layer part 210 and the width of the layer part 220 and the difference between the positions of the cap part 110 and the cap part 120 in the tire shoulder between the outer side when the vehicle is mounted and the inner side when the vehicle is mounted. PRCF can be generated. That is, the pneumatic tire 10 can generate necessary and sufficient PRCF only by the internal structure such as the belt layer without depending on the tread pattern.

  In the present embodiment, the difference between the width W1 and the width W2 is set to 20% or more of the width of the layer portion 210 located on the stepping side of the steel cord 37, and the layer portion 210 is 30 mm or more. For this reason, the amount of PRCF generated can be increased or the amount generated can be adjusted more easily.

  In the present embodiment, the cap portion and the pair of layer portions are so-called jointless spiral shapes that do not have a joint portion in the tire circumferential direction. This is not preferable because the amount of deviation at the time of winding around the belt 36 is likely to be large, and the workability at the time of manufacture is difficult. From this viewpoint, the difference between the width W1 and the width W2 is preferably 8 mm or less.

(6) Other Embodiments As described above, the contents of the present invention have been disclosed through the embodiments of the present invention. However, it is understood that the description and drawings constituting a part of this disclosure limit the present invention. Should not. From this disclosure, various alternative embodiments, examples, and operational techniques will be apparent to those skilled in the art.

  For example, the embodiment of the present invention can be modified as follows. In the above-described embodiment, the cap portion (cap portions 110 and 120) and the layer portion (layer portions 210 and 220) are continuously and integrally formed. However, the cap portion and the layer portion are separate. There may be. In the embodiment described above, the cap portion is divided into the cap portion 110 and the cap portion 120, but the cap portion 110 and the cap portion 120 may be integrally formed.

  In the embodiment described above, the steel cord is used for the belt layer 30, but an organic fiber cord may be used instead of the steel cord.

  As described above, the present invention naturally includes various embodiments that are not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

DESCRIPTION OF SYMBOLS 10 ... Pneumatic tire, 20 ... Carcass, 30 ... Belt layer, 30a, 30b ... End, 31 ... First belt, 32 ... Steel cord, 35 ... Cushion rubber, 36 ... Second belt end, 37 ... Steel cord 37a, 37b ... end, 40 ... bead, 100 ... belt reinforcing layer, 110 ... cap, 110a, 110b ... end, 120 ... cap, 120a, 120b ... end, 210, 220 ... layer, CL ... tire equator line

Claims (6)

A belt layer in which a plurality of cords disposed obliquely with respect to the tire circumferential direction are covered with rubber;
A belt reinforcing layer disposed on the outer side in the tire radial direction than the belt layer,
The belt reinforcing layer is
A cap that covers the entire belt layer;
A pneumatic tire having a pair of layer portions covering both end portions in the tread width direction of the belt layer,
The width of one layer portion constituting the pair of layer portions is different from the width of the other layer portion,
The length from the tire equator line passing through the center in the tread width direction of the pneumatic tire to one end portion in the tread width direction of the cap portion is from the tire equator line to the other end portion in the tread width direction of the cap portion. Pneumatic tire different in length.   The width of the layer portion located on the stepping side of the cord that comes into contact with the road surface in advance with rolling of the road surface of the pneumatic tire is located on the kicking side of the cord that comes into contact with the road surface later The pneumatic tire according to claim 1, wherein the pneumatic tire is wider than a width of the layer portion.   The length from the tire equator line of the cap portion located on the stepping side of the cord that comes into contact with the road surface first with the rolling of the road surface of the pneumatic tire is the length of the cord that comes into contact with the road surface later. The pneumatic tire according to claim 1 or 2, wherein a length of the cap portion located on the kicking side is longer than a length from the tire equator line. The belt layer is composed of a plurality of belts,
The pneumatic tire according to claim 2, wherein the cord is a cord included in the belt that is positioned on the outermost side in the tire radial direction.   The difference between the width of the layer portion located on the stepping side and the width of the layer portion located on the kicking side is 20% or more of the width of the layer portion located on the stepping side. The pneumatic tire as described in any one of thru | or 4.   The pneumatic tire according to any one of claims 2 to 5, wherein a width of the layer portion located on the stepping side is 30 mm or more.

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