JP5961671B2 - Pneumatic solid tire - Google Patents

Description

  The present invention relates to a pneumatic solid tire used for industrial vehicles and the like, and more particularly to an improvement of a pneumatic solid tire with improved rim slip resistance.

  Pneumatic solid tires are used for traveling on rough roads with relatively low speed and high load, and sometimes scattered with nails, pieces of wood, rocks, etc. Therefore, rim slip resistance against excessive external inputs (traction, brake, side force) is required.

  For this reason, in order to increase the fixing force (creep) between the tire and the rim and suppress the rim slip, a bead is disposed in the base rubber layer, or a plurality of the base rubber layer is disposed in the base rubber layer as described in Patent Document 1. Techniques have been proposed in which layer reinforcing cords are stacked in the tire circumferential direction.

  However, with such a technique, when a large deformation or fatigue failure of the tire occurs, there is a possibility that the cord may be cut or the rubber around the cord may be separated.

  In addition, as shown in FIG. 6 (a), the pressure direction during vulcanization and the flow of rubber in the cross-sectional view in the width direction of the unvulcanized tire, the vulcanization of the green tire in the vulcanization mold is performed. The green tire is composed of cords that are inclined with respect to the circumferential direction of the green tire by forcibly compressing and deforming in the width direction so as to correspond to the cavity shape of the vulcanization mold. The cord layers are compressed in the tire width direction, local strain due to buckling as exemplified in FIG. 6B occurs in the cord layers, and variations in the arrangement of the cord layers may occur. The tire durability and rim slip resistance could not be reduced.

JP-A-6-127206

  Therefore, the present invention provides a pneumatic solid tire in which the durability of the tire is particularly improved without reducing the rim slip resistance.

The pneumatic solid tire according to the present invention is formed by arranging two or more cord layers inclined in the tire circumferential direction in a rubber layer, and the tire posture before assembly to an applied rim, code layer, the region in the vicinity of the tire equatorial plane, will be provided with one of the gap portion, of the cord layer, the maximum width Bd of the tire width direction, and a 0.57D or more with respect to rim width D, and, tire width direction maximum width S of the front Symbol gap is characterized in that it is less 0.41Bd.

Here, the rubber of the rubber layer is not only composed of rubber of the same rubber type, but may be two or more types of rubber, two or more types of rubber, or a combination thereof.
As the cord of the cord layer, an organic fiber cord can be used in addition to the steel cord.
The vicinity of the tire equator plane means a range of ± 10% of the rim width around the tire equator plane.

More preferably the pneumatic type solid tires, such as this, the code layer, the maximum width Bd of the tire width direction, with at 0.8D or less with respect to rim width D, the tire radial direction from the rim diameter line The maximum height h1 is 0.05H to 0.45H with respect to the tire cross-section height H, and the tire radial direction minimum height h2 from the rim diameter line satisfies the relationship of 0.01H to 0.40H.

  Here, the maximum height h1 in the tire radial direction is the distance from the rim diameter line to the outermost position in the radial direction of the cord layer in the cross section in the tire width direction, and the minimum height h2 in the tire radial direction is the tire width. In the direction cross section, the distance from the rim diameter line to the innermost position in the radial direction of the cord layer is meant.

Also preferably, the tire width direction maximum width S of the front Symbol gap portion is 1mm or more.

  Preferably, the cords of the two cord layers are inclined at an angle of 5 ° to 80 ° with respect to the tire circumferential direction, and the cords of the respective cord layers are crossed with each other.

  In the pneumatic solid tire according to the present invention, in the tire posture before assembling to the applied rim, the cord layer is provided with at least one gap in the region near the tire equatorial plane, so that FIG. As shown in the cross-sectional view in the width direction of the unvulcanized tire, the bending direction of the cord against compression in the width direction during vulcanization is reduced, and the bending deformation is absorbed by the rubber in the gap. Thus, the buckling of the cord layer can be reduced. As a result, the durability and rim slip resistance of the tire can be improved.

FIG. 4 is a cross-sectional view in the width direction of an unvulcanized tire in which the pressure direction during vulcanization and the flow of rubber are illustrated. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a tire meridian cross-sectional view of a tire posture before assembly to an applied rim, showing an embodiment of a pneumatic solid tire of the present invention. It is a figure which shows the distance of the rim line of a tire, and the flange end. (A) is a figure which shows the relative relationship between the clamping pressure of a tire and a rim | limb, and traveling distance, (b) is a figure which shows the relative relationship between the frictional force at the time of rolling of a tire, and traveling distance. is there. (A) And (b) is a tire meridian sectional view in the tire posture before assembling to an applicable rim, showing a conventional pneumatic solid tire. (A) is a pressure direction at the time of vulcanization, and a cross-sectional view of the rubber flow in the width direction of the unvulcanized tire, and (b) schematically shows the occurrence of local distortion due to buckling during vulcanization. FIG.

Hereinafter, the pneumatic solid tire of the present invention will be described in detail with reference to the drawings.
The pneumatic solid tire shown in FIG. 2 includes an annular base rubber layer 1 assembled to a rim, and a tread rubber layer 2 disposed on the outer side in the tire radial direction of the base rubber layer 1.

In such a tire, the base rubber layer 1 can use a rubber having a high compression elastic modulus in order to increase the fitting pressure with the rim, and the tread rubber layer 2 can be made of rubber having excellent wear resistance and cut resistance. Can be used.
In addition, a middle rubber layer having excellent cushioning properties and the like can be disposed between the base rubber layer and the tread rubber layer in order to improve the riding comfort of the vehicle.

  In the base rubber layer 1, preferably, two layers of cord layers 3 that are inclined at an angle of 5 ° to 80 ° with respect to the tire circumferential direction and the cords of the respective cord layers are interlaced with each other are arranged.

  In this pneumatic solid tire, at least one, in the drawing, one gap portion 4 is provided in the region of the cord layer 3 near the tire equatorial plane.

  More preferably, in such a pneumatic solid tire, the maximum width Bd of the cord layer in the tire width direction is 0.2D to 0.8D with respect to the rim width D, and the maximum in the tire radial direction from the rim diameter line. The height h1 is 0.05H to 0.45H with respect to the tire cross-section height H, and the tire radial direction minimum height h2 from the rim diameter line satisfies the relationship of 0.01H to 0.40H.

  With this configuration, the shape change of the base rubber layer 1 is reduced under the action of the cord layer so as to show the relative relationship between the tightening pressure between the tire and the rim and the travel distance in FIG. The tire tightening pressure can be increased, and the contact between the tire and the rim can be achieved by the hook effect of the cord, as shown in FIG. 4 (b). It is possible to make the tire circumferential contact pressure distribution at the part uniform and keep it uniform during rolling of the tire and improve the frictional force with the rim. As a result, it is possible to improve the rim slip resistance and to make it effective in the change with time after running.

In addition, preferably, there is one gap portion 4 and the maximum width S in the tire width direction of the gap portion 4 is 1 mm or more, and by making it within this range, both the durability of the tire and the effect of rim slip resistance are achieved. be able to.

  That is, when the maximum width S in the tire width direction is less than 1 mm, the left and right cord layers separately arranged cross and restrain at the tire center, thereby generating local strain stress and raising the concern about durability. On the other hand, if it exceeds 0.6 Bd, the fitting force with the rim at the base center portion of the tire is lowered, and the rim slip resistance, which is the original purpose, may be lowered.

  Preferably, the cords of the two cord layers are inclined at an angle of 5 ° to 80 ° with respect to the tire circumferential direction, and the cords of the respective cord layers are interlaced with each other, so that the cord corresponding to the external input of the tire is obtained. The restraining force of the rim can be relaxed, and in particular, the rim slip property can be reduced.

  Preferably, the base rubber layer 1 is interspersed with organic fibers as short fibers, so that the tensile strength of the base rubber layer 1 can be particularly improved and the fitting force with the rim can be improved.

Next, pneumatic tires having a structure as shown in the figure were made on a trial basis, and the tires of Examples 1 to 4 were changed to the rims shown in Table 1 with the respective specifications shown in Table 2. The rim slip amount was measured for each of the comparative tires 1 and 2.
In addition, in the cord layers of the tires 1 to 4, a steel cord having a strength per cord = 902 (N) is inclined with respect to the tire circumferential direction at a total strength = 105350 (N) per tire. Arrange at an angle of 72 °.
The comparative tire 1 is a tire in which nylon cords are arranged in multiple layers along the tire circumferential direction, and the comparative tire 2 is a tire in which two layers of steel cords are arranged at an inclination angle of 72 ° with respect to the tire circumferential direction. Since the comparative example tire does not require modification other than not providing a gap portion, it was assumed to conform to the example tire.

(Rim resistance)
Each tire is assembled to a rim and mounted on a forklift. After each running period, the relative circumferential displacement (rim slippage) between the rim and the tire is measured, and the results are shown in Table 3. Show.
In addition, it shows that rim slip resistance is excellent, so that the value in a table | surface is small.

  From the results shown in Table 3, the tires of Examples 1 to 4 were able to improve the rim slip resistance by providing a gap with respect to the comparative tires 1 and 2.

A tire having a structure as shown in the figure was made as a trial, and as shown in Table 4, for each of Example tire 5 and Comparative Example tires 3 to 6 in which the respective specifications were changed, rim slip resistance, The rim assembly property, rim fit property, durability, and the curve pp value of the product cross-section cord were measured.
In addition, since the comparative example tire does not require modification other than not providing a gap portion, it was assumed to conform to the example tire.

(Rim resistance)
Each of Example Tire 5 and Comparative Example Tires 3 to 6 is assembled to a rim of size 250-15 and attached to a front load wheel of a 3.5-ton forklift, and under conditions where rim slip actually occurs. A tire radial line is attached to the rim-tire contact portion (flange top) so that the tire and rim are aligned before running, and the amount of rubbing is measured after one month, and the evaluation results are shown in Table 5. Shown in
In addition, it shows that it is excellent in rim slip resistance, so that the slip amount after driving | running | working is small.

[Rim assembly]
For each of Example Tire 5 and Comparative Example Tires 3 to 6, when assembling to a rim of size 250-15, the same type tire was measured twice each time, and the average value of the required time was obtained. The evaluation results are shown in Table 5.
In addition, it shows that it is excellent in rim | limb assembly property, so that required time is short.

(Rim fit)
Each of the example tire 5 and the comparative example tires 3 to 6 is assembled to a rim of size 250-15, and the distance t between the tire rim line and the flange end is set to be equal to eight on the tire circumference as shown in FIG. The measurement was made at each location, and the maximum value-minimum value was defined as eccentricity pp. The evaluation results are shown in Table 5.
It should be noted that the tire eccentricity pp value does not become 3 mm or more as a judgment value in consideration of variation after actually confirming and setting as a region where vibration problems do not occur in the evaluation of actual vehicle riding comfort. The smaller the value, the better the rim assembly.

〔durability〕
Each of Example Tire 5 and Comparative Example Tires 3 to 6 is assembled to a rim of size 250-15 and attached to the front load wheel of a 3.5-ton forklift, and the vehicle running time meter is used to start the test. When the vehicle traveled for 2000 hours, the tire was removed from the vehicle, the appearance of the tire and the presence or absence of a durable defect in dissection were confirmed, and the evaluation results are shown in Table 5.

[Curve pp value of product cross-section code]
For each of the example tire 5 and the comparative example tires 3 to 6, after the actual vehicle test, the tires were cut evenly on the circumference in eight cross-sectional directions so that the radial height of the cord layer in the base rubber layer Evaluation was made on (= h1-h2), and the evaluation results are shown in Table 4.
Note that the cord curve pp value is an average of pp values obtained by providing eight equal samples on the tire circumference, and the smaller the value, the durability, as well as rim assembly and rim fit. It is excellent in.

  From the results of Table 5, the tire 5 of the example is provided with a gap with respect to the tires 3 to 6 of the comparative example, so that the rim slip resistance, the rim assembly property, the rim fit property, the durability, and the curve of the product cross-section cord are obtained. The p-p value could be improved.

1 Base rubber layer 2 Tread rubber layer 3 Cord layer 4 Gap

Claims (4)

In a pneumatic solid tire in which two or more cord layers inclined in the tire circumferential direction are disposed in the rubber layer,
In the tire posture before assembling to the applied rim, the gap between the cord layer and the tire equatorial plane is provided with one gap,
The maximum width Bd of the cord layer in the tire width direction is 0.57D or more with respect to the rim width D, and the maximum width S of the gap portion in the tire width direction is 0.41 Bd or less. Pneumatic solid tire. The maximum width Bd in the tire width direction of the cord layer is 0.8D or less with respect to the rim width D, and the maximum height h1 in the tire radial direction from the rim diameter line is with respect to the tire cross-section height H. 2. The pneumatic solid tire according to claim 1, wherein the tire radial minimum height h2 from the rim diameter line satisfies a relationship of 0.01H to 0.40H at 0.05H to 0.45H. The pneumatic solid tire according to claim 1 or 2 , wherein a maximum width S in the tire width direction of the gap is 1 mm or more. The code in layer two layers is inclined at an angle of 5 ° to 80 ° with respect to the tire circumferential direction, and in another by interlacing the codes of each code layer according to any one of claims 1 to 3 Pneumatic solid tire.

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