JP2006347320A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of establishing the rim assembling easiness and the resistance against rim abrasion compatibly in good balance. <P>SOLUTION: The angle of the bead bottom surface confronting the rim seat surface to the tire axial direction is made different between a left and a right bead part 2, and at least on the side with the bead heel, the angle outside the vehicle is made greater than the inside. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire in which rim assemblability and rim rubbing resistance are both balanced.

  For pneumatic tires, the rim assembly property and the rim rubbing resistance have mutually contradictory properties, and how to balance them is an extremely important issue. That is, when sweet fitting is used to improve rim assembly, the movement of the bead portion seated on the seat surface of the rim during traveling increases, and the rim accompanying separation or cutting of the carcass layer near the rim flange. If it is easy to cause rubbing failure and improves rim rubbing resistance, the tire cannot be smoothly mounted on the rim, the rim assembling property deteriorates, and the roundness cannot be maintained in the tire after assembling the rim. Will get worse.

  These rim assembly and rim rubbing resistance are greatly affected by the form of the bottom surface of the bead seated on the seat surface of the rim, and the rim rubbing resistance is improved as the angle between the bead bottom surface and the tire axial direction increases. It has been found that the smaller the angle, the better the rim assembly property and the better the fit with the rim.

Conventionally, as a measure for achieving both of these performances, the angle between the bottom surface of the bead and the tire axial direction is set to 5 to 25 ° (see, for example, Patent Document 1), or this angle is set to 0 to 7 ° on the bead heel side. There is a proposal of forming in two steps of 8 to 15 degrees on the side (see, for example, Patent Document 2). However, in an actual tire, the influence of the bead bottom surface angle on the rim rubbing resistance differs greatly between the bead portion located outside the vehicle and the bead portion located inside. The measure was not satisfactory.
JP 2000-198327 A Japanese Patent Laid-Open No. 7-156616

  An object of the present invention is to solve such a conventional problem and to provide a pneumatic tire in which the rim assembling property and the rim rubbing resistance are both balanced.

  The pneumatic tire of the present invention is a pneumatic tire provided with a pair of left and right bead portions that are seated on the rim seat surface, and an angle formed between the tire axial direction of the bottom surface of the bead facing the rim seat surface is different between the left and right bead portions. The angle is made larger at the outside of the vehicle than at the inside at least on the bead wheel side.

  According to the present invention, the bead portion on the vehicle outer side is made larger than the vehicle inner side at least the bead wheel side tire axial direction on the bead bottom surface on the vehicle outer side that greatly affects the rim rubbing resistance. The movement of the rim is effectively suppressed, and an excellent rim rubbing suppression effect is exhibited. On the inner side of the vehicle where the movement of the bead portion is relatively small, the angle between the bead bottom surface and the tire axis direction is suppressed to suppress the rim. By providing a fit effect, it is possible to achieve both rim scuff resistance and rim assembly properties in a well-balanced manner.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a sectional view showing an example of a pneumatic tire according to an embodiment of the present invention, and FIG. 2 is a sectional view showing an example of a pneumatic tire according to another embodiment of the present invention.

  In FIG. 1, a pneumatic tire 1 includes a pair of left and right bead portions 2 and 2 that are seated on a rim seat surface (not shown). In the pneumatic tire 1 of the present invention, the angle between the bottom surface of the bead facing the rim seat surface and the tire axial direction is different between the left and right bead portions 2 and 2, and at least the bead heat at the bottom surface of the bead. The angle on the left side (the entire surface in the figure) is different between the outside and the inside of the vehicle when mounted on the vehicle.

  That is, the angle of the bottom surface of the bead is α1 on the outside of the vehicle located outside the vehicle when the vehicle is mounted, and this angle is α2 on the bottom surface of the bead inside the vehicle, and the relationship between the angle α1 and the angle α2 is α1> α2 is set.

  In this way, at the outside of the vehicle where the movement of the bead portion 2 that is originally traveling increases, the bead portion 2 on the outside of the vehicle is increased by making the angle of at least the bead wheel side of the bottom of the bead larger than the inside of the vehicle. In order to ensure good rim assembly by suppressing the angle of the bottom of the bead at the bead portion inside the vehicle where the movement of the bead portion 2 is relatively small. Yes.

  As a result, an excellent rim rubbing suppression effect can be imparted to the bead portion 2 outside the tire, and a fit effect with the rim can be independently imparted to the bead portion 2 inside the tire. The rim rubbing property can be balanced with a good balance.

  In the present invention, the angle of the bead bottom surface refers to the angle of the bead surface facing the seat surface of the rim. Specifically, the width between the bead heels in the left and right bead portions 2 matches the rim width. The angle between the bottom surface of the bead and the tire axial direction.

  In the pneumatic tire 1 of the present invention, the angles α1 and α2 of the bead bottom surface described above may be set such that 7 ° <α1 <15 ° and 4 ° <α2 <12 °. If the angles α1 and α2 are too small, the rim rubbing resistance will be insufficient. If the angles α1 and α2 are too large, the rim rubbing resistance will be deteriorated. May be.

  The left and right bead bottom surfaces in the present invention are formed at angles β1 and β2 different from the bead wheel side angles α1 and α2 on the bead toe side, as illustrated in FIG. Can be formed in two different stages on the bead wheel side and the bead toe side. In this case, the sizes of the angles β1 and β2 are not particularly limited, but it is preferable that β1> α1 and β2> α2 as shown in FIG. Thereby, the fitting property and air sealing property of the tire can be ensured satisfactorily.

  As described above, in the pneumatic tire according to the present invention, the angle formed with the tire axial direction of the bottom surface of the bead is different between the left and right bead portions, and at least the angle on the bead wheel side is set at the bead portion outside the vehicle. By making it larger than the inner bead part, the rim rubbing suppression effect is given to the bead part on the outer side of the vehicle, and the fit effect with the rim is independently given to the bead part on the inner side of the vehicle. The rim rubbing resistance is balanced and can be widely applied to pneumatic tires for which the mounting position on the vehicle is designated.

  A book with tire size (205 / 55R16), tire structure (Fig. 2), and tire specifications in common, and angles α1, β1, α2, and β2 formed with the tire axial direction on the bottom surface of the bead as shown in Table 1. Invention tires (Examples) and comparative tires (Comparative Examples 1 to 4) were prepared.

  For these five types of tires, the fitting pressure (kPa) and the rim rubbing amount (mm) were measured by the following methods, respectively, and the results are also shown in Table 1.

[Measurement of mating pressure]
Wipe the area around the bead with soapy water, measure the fitting pressure (kPa) when fitted to a standard rim (16 × 6 1 / 2JJ), and use the result as a reference for evaluation of rim assembly. The tires of the present invention (Examples) are shown in Table 1 with an index of 100. The smaller the value, the better the rim assembly.

[Measurement of rim rubbing amount]
Each tire was filled with an air pressure of 220 kPa and mounted on a domestic car, and the amount of rim rubbing (mm) was measured by applying rapid braking from a speed of 50 km / h, and the result was used as a criterion for evaluating rim rubbing resistance. The smaller the value, the better the rim scuff resistance.

  From Table 1, it can be seen that the rim assembly property and the rim rubbing resistance are well balanced in the tire of the present invention as compared with the comparative tire.

It is sectional drawing which shows an example of the pneumatic tire by embodiment of this invention. It is sectional drawing equivalent to FIG. 1 by other embodiment of this invention, and has expanded and showed the principal part of the bead part on either side in the figure.

Explanation of symbols

1 Pneumatic tire 2 Bead part

Claims (3)

In a pneumatic tire provided with a pair of left and right bead portions to be seated on the rim seat surface,
A pneumatic tire in which an angle formed with the tire axial direction on the bottom surface of the bead facing the rim seat surface is made different between the left and right bead portions, and at least on the bead wheel side, the angle is larger on the outside of the vehicle than on the inside. .   The pneumatic tire according to claim 1, wherein the angle is set to be more than 7 ° and less than 15 ° outside the vehicle, and more than 4 ° and less than 12 ° inside the vehicle. The pneumatic tire according to claim 1 or 2, wherein the angle is formed in two stages different on the bead wheel side and the bead toe side.

Images