JPS61193902A - Pneumatic tire with reinforced belt for passenger vehicle - Google Patents

Abstract

PURPOSE:To improve the vibration suppressing performance under harshness region by employing cord arrangement with inclination in the opposite direction against the meridian face of tire and specific range of inclination angle of projection onto the equator face of tire. CONSTITUTION:The ply cords 2, 2' extending along the opposite sidewalls of tire are arranged near the maximum width B position of troidal carcass 1 such that the inclination in opposite direction against the meridian face (L) of tire, especially of the projection onto the equator face (m) of tire will be within the range of 3-30 deg.. The carcass is overlapped with a margin (w) of 20-120mm in the center of crown section where said margin is cross laminated with cord arrangement in micro angle smaller than 30 deg. against the equator face of tire and made narrower than the belt 3.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) For pneumatic tires, especially those used for passenger cars, it is important to improve the vibration riding comfort.

In recent years, this type of tire has achieved remarkable improvements in performance due to the introduction of a radial structure carcass, but in terms of vibration ride comfort, the inventors have We conducted research and development on vibration damping that is effective for reducing vertical vibration in the vibration range of about 50 to 100 Hz, the so-called harshness range.The results of this development are described below. Comfort can be improved by adding a so-called layer or cap belt to the belt combined with the radial structure carcass, especially when the vehicle speed is 2.
Although it is possible to reduce vertical vibration at relatively low speeds of about 0 to 50Ks/hr, the vehicle speed is 60Km/h.
If it exceeds r, it will only get worse (the above reduction effect is only an improvement of about 66% at most compared to the control lacking the above belt reinforcement means, and the increase in cost for said reinforcement is not enough). is small.

Regarding such conventional technology, see Japanese Patent Application Laid-open No. 471480.
5 and QOIS No. 58-61 may be referred to.

(Problem to be Solved by the Invention) 50 to 10
It is an object of the present invention to provide a tire structure that can lead to a more effective vibration damping effect in a vibration region of approximately 0 Hz, the so-called harshness region. The requirements can be appropriately met by incorporating the following into the tire configuration. In other words, it is a pneumatic tire whose main reinforcement is a toroid-shaped carcass and a belt placed around the crown of the tire. The ply cords extending along the sidewall of the tire in the vicinity of are tilted in opposite directions to the tire meridian plane, and the angle of the tilt is in the range of 8 to 30 degrees when projected onto the equatorial plane of one tire. It is assumed that the code sequence is as follows.

It goes without saying that the meridian plane of the tire here corresponds to the plane that includes the rotational axis of the tire, and the tire equatorial plane corresponds to the plane that passes through the center of the width of the tire and is orthogonal to the meridian plane. ◎ An example of the above carcass configuration As illustrated in Fig. 1, ply roots 2 and 2' extending along both sidewalls of the tire near the maximum width B of the toroid-shaped carcass 1 are connected to the meridian plane l of the tire. The cord arrangement is such that the angle θ of the inclination is in the range of δ to 80° when projected onto the equatorial plane m of the tire.

In this example, carcass 1 has a diameter of 2.20 at the center of its crown.
This shows the case where the tires are overlapped with an overlap width W that allows the range of ~l g Belt 8 is an example in which the cords are arranged in a small angle of 8G' or less with respect to the equatorial plane and are cross-laminated with each other.
However, by using a ply with a two-stage refraction cord arrangement similar to that shown in FIG. 2(b), there is no need for overlapping.

In either case, as seen from the side of the tire T in FIG. The angle of intersection with l, that is, the angle of inclination, is θ, and the inclinations are opposite to each other, such as -0.

The value (absolute value) of θ and -〇 is 8 to 80 as already mentioned.
0, and when this tire rotates forward as shown in FIG.
It is preferable to install it on the vehicle so that the stepping side of the contact area is in the direction of inclination at θ.

(Function) When a carcass-structured tire with the above cord arrangement is assembled with a rim and filled with internal pressure, each ply cord 2.2I in both sidewalls 4 will have a small inclination angle with respect to the meridian plane of the tire. Under the deformation, the tire undergoes torsional deformation around its axis of rotation, and as a result, the sidewall 4 undergoes shear deformation. This shear deformation is caused by the sidewall rubber impacting the cord plies 2, 2'. The load on the air pressure increases, and the tension applied to each ply cord decreases accordingly, while the air pressure load that cannot be filled by the shear deformation of the side worm rubber alone prompts an increase in the tension on the belt 8.

By the way, regarding vibration riding comfort performance and vibration reduction in the vergeness region ranging from SO to 1001iZ, the effectiveness of lowering the radial spring constant k and increasing the circumferential tension S in the ring model 6 shown in FIG. is clear.

Therefore, according to this invention, the tension reduction of the ply cords 2, 21 in the sidewall 4 is reduced by the above-mentioned ring model 6.
The decrease in the radial spring constant of 1 and the increase in belt tension resulting from the shear deformation of the sidewall 4 result in an increase in the circumferential tension S, which contributes to vibration reduction in the harshness region. be able to.

Here, the tension of the ply cord 2.21 has a proportional relationship with the spring constant, and with the above-mentioned slanted cord arrangement, the spring constant was found to be reduced by 7 to 8% as a result of the experiment. Since the spring constant is proportional to the tire axial force, as the spring constant decreases, the axial force also decreases.

It should be noted that the increase in belt tension also reduces the tire input power in the same way as the increase in the out-of-plane bending rigidity of the belt portion due to the belt reinforcement means mentioned at the beginning, which reduces the vibration input entering the tire.

As described above, the present invention provides an improvement in vibration riding comfort.

(Example) For a tire size of 1715770SR18, a test tire of the present invention shown in FIG.
) and the conventional tire shown in Figure 8 as a control, we compared the axial force characteristics when passing over a single-pronged REIT, and compared the control with 10
The results are shown in the table below using an index value of 0, and Figure 9 (
a).

In (1)), the axial force of vertical and longitudinal vibrations is illustrated in relation to vehicle speed in comparison with control.

In the figure, the solid line is the control, and the #IIl and broken lines are the performance of the tire of the present invention. In particular, the broken line is the performance in the case of reverse rotation (#!4 in the opposite direction).

As is clear from the above table and FIG. 9, the embodiment of the present invention brings about a nearly 20% reduction in the axial force compared to the four-wheel control system, especially in low-speed vertical vibration. (Effects of the invention) ) This invention improves the vibration ride quality of a pneumatic tire without the need to use belt reinforcement means, and without the attendant negative effects. can bring.

[Brief explanation of the drawing]

Figure 1 is a skeleton diagram showing the carcass structure of the tire, Figure 2 (
a) and (b) are plan development views of individual embodiments, Fig. 8 is a side view, Fig. 4 is an explanatory diagram of ease of use, Fig. 6 is a vibration schematic diagram, Fig. 6 is an example, Figure 7 is a comparative example, Figure 8 is a sectional view of each control, and Figure 9 is a performance comparison graph. 1...◆Carcass 2...Ply cord 8.
- Belt 4... Sidewall Patent applicant Bridgestone Corporation Figure 1 Figure 2 (a) (b) Figure 3 Figure 5 Figure 7vA (a) (b)

Claims (1)

[Scope of Claims] 1. A pneumatic tire whose main reinforcement is a toroid-shaped carcass and a belt arranged around its crown, wherein the carcass is assembled with a rim and filled with internal pressure. , the ply cords extending along both sidewalls of the tire in the vicinity of the maximum width position are tilted in opposite directions with respect to the tire meridian plane, and the angle of the tilt when projected onto the tire's equatorial plane is A belt-reinforced pneumatic tire for a passenger car, characterized by having a cord arrangement in the range of 3 to 30 degrees. 2. The tire according to 1, wherein the carcass consists of a pair of left and right plies that overlap at the center of the crown portion. 3. The tire according to 2, wherein the ply overlap of the carcass is at least 20 mm and does not exceed 120 mm.