JPS6094803A - Belt reinforced pneumatic rubber tire with comfortableness to drive - Google Patents

Abstract

PURPOSE:To improve comfortableness to drive without impairing various characteristics by interposing both side areas of a belt of the captioned tire by means of the layer of additional reinforcement made of rubberized organic fiber cord of predetermined breadth, special characteristic and special structure. CONSTITUTION:Layers 7, 8 of additional reinforcement, made of the rubberized layer of organic fiber cord with the breadth of 25-35 as much as that of a tread part 1, are arranged on the outside of the outermost layer and also on the inner side of the innermost layer in the radial direction of a tire in such a manner as a part of said layers slightly bulges out from the belt 5 in both side areas of the belt 5. This organic fiber cord is formed by arranging aromatic polyamide fiber cord, with elasticity of 600-4,000kgf/mm.<2> at the time of expansion by 10%, by density of driving of 20.7 pieces/25mm. and in the direction of substantially dividing into halves a rhombic latticework formed by metal cords of the belt 5. Due to this structure, comfortableness to drive can be improved without deteriorating characteristics such as resistance to abrasion and the like.

Description

[Detailed Description of the Invention] (Technical Field) The technical content described in this specification regarding a belt-reinforced pneumatic rubber tire with good riding comfort is applied to a belt-reinforced pneumatic rubber tire that provides a comfortable ride. The technical field of pneumatic rubber tires with belt reinforcement has been succumbing to development results that have achieved appropriate improvement in riding comfort through effective suppression of elastic vibrations transmitted to the vehicle through the tires. occupies .

(Background technology) A typical example of a pneumatic rubber tire that generally has belt reinforcement is widely used as a radial tire, and this radial carcass structure tire has excellent wear resistance, cornering, braking, etc. It is much more advantageous than the previous ear carcass structure. This consists of at least two rubberized layers sandwiching the tire's equatorial plane, that is, the plane that includes the center circumference of the tire's nose between the trend and the carcass, and having metal cords arranged in a direction that intersects each other at a relatively shallow angle. This is due to the fact that the so-called stiffening effect is produced in the carcass by using a belt made of a thin material, increasing the rigidity of the tread portion in both the vertical and horizontal directions.

(Prior art and points of interest) However, the rigidity of this tread section is due to its ability to flex and wrap around obstacles such as protrusions on the road surface (hereinafter referred to as enveloping). Since the ml (referred to as "resistance") is significantly reduced, the reaction force of the protrusion exerts a reaction force on the tire as a source of vibration, impairing the ride quality.

As a method to improve the riding comfort performance, the above-mentioned enveloping property can be improved by increasing the interlayer intersection angle of the metal cords in the belt, narrowing the belt width, etc., and reducing the belt Ml property of tire bending. Attempts have been made to improve this, but as a result, the restraining performance at the end of the belt is forced to suddenly decrease, and as a result, the anti-wear performance at a portion of the tread shoulder decreases, which is disadvantageous in terms of the wear resistance of the tire. In addition, although the level of vibration in the vertical direction of the vehicle's lashes is reduced in this way, the level of vibration in the longitudinal direction also increases, and it has been found that these cannot be improved at the same time.

(Start of the idea) From the perspective of optimal tread rigidity, the inventor clarified the mechanism of the reciprocal relationship between vertical vibration and longitudinal vibration mentioned above, and set out to improve the vertical vibration level simultaneously and significantly. As a result of our research, we have found that, contrary to the conventional idea of reducing the vertical stiffness of the tread, which spans the entire lateral direction of the tread, we have found that areas on both sides of the belt are made of two or more rubberized layers using metal cords. In,
It has been found that by distributing an additional reinforcing layer of an organic fiber hood having a specific elasticity over a certain range of recesses, vertical and il+backward vibrations can be reduced simultaneously and by a large amount.

(Purpose of the Invention) Based on what has been elucidated as a result of repeated experiments based on the above knowledge, it is necessary to improve the riding comfort of pneumatic rubber tires with belt reinforcement, and to improve the wear resistance among other tire properties. It is an object of the present invention to effectively improve this without having to do so.

(Structure of the Invention) The above purpose is appropriately achieved by a mechanism based on the following matters.

Sidewalls and bead parts are provided on both sides of a cylindrical tread part, and these parts are arranged on a radial surface that extends from one bead part to the other bead line and is perpendicular to the plane containing the center circumference of the tread part, or relatively shallow thereto. a carcass consisting of at least plies using cords extending in planes that intersect at an angle; For belt-reinforced pneumatic rubber tires reinforced with a belt consisting of at least two rubberized layers with gold cords arranged in cross directions, the width of the belt is between 25 and 85% of the width of the tread. Both side areas have an additional reinforcing layer consisting of a rubberized layer of organic fiber cord which is placed between the inner and outer sides of the tire in the radial direction so as to protrude slightly beyond the side edges, and the organic fiber cord has a 10% elongation F. #9f looseness rate from 600 to 4000
A belt-reinforced pneumatic tire with good riding comfort, characterized in that it is arranged in a direction that substantially bisects a diamond-shaped lattice formed by the gold R cord of the belt.

The carcass is hereby provided with plies of organic fiber cord, the cords of the additional reinforcing layer being arranged in turns substantially parallel to the central circumference of the tread plate, including said circumference. T in a folded arrangement that wraps around the first end of the belt in a direction substantially perpendicular to the plane;
0% elongation elasticity 2000~4 (100kgf/
It is more preferable to set it to su·2.

(Specific explanation according to illustrations) Now, Fig. 1 shows a cross section of a general radial tire.
In the figure, 1 is a tread part, 2 is a sidewall 1, 3 is a bead part, and 4 is a J-ply extending from one bead part to the other bead part, in this example, the above-mentioned cross section, that is, the radial plane of the tire. The carcass, 5 is a gold cord sandwiching the plane (equatorial plane) including the central circumference of the tread part J and 6 from each other.
An angle within 0° (therefore less than 300 with respect to the equatorial plane)
In this example, the belt is made of two rubberized layers arranged in a direction that intersects with each other, and is also a 6G bead core. Hard rubber filler 7
The bead portion 3 is hardened by arranging the .

Fig. 2 shows a comparative tire in which the radial tire shown in Fig. 1 is used as a mount roll, and the width of the belt 5 across the width of the tread portion is narrowed by approximately 0. A somewhat exaggerated schematic illustration (a) of the envelope property when overcoming a protruding road surface obstacle O extending in the running direction of the tire at a degree of 10 w, and a similar illustration (b) of the control. Stepping upward with the middle arrow F■ contrasts the reaction force.

At this time, the axial force p-
The relationship between the p value (i.e., the difference between the maximum and minimum values of the reaction force FV) and the tire circumferential speed is shown in Figures 3 (a) and (b), respectively. The solid line and the performance of the comparative tires are compared with the broken line.

Both figures show that compared to the control tire, the comparative tire with a narrower belt width has a reduced vertical axial force p-p, but the previous model's axial force p-p has worsened, and from this, the vertical As mentioned earlier, it is difficult to reduce stiffness at the same time by considering envelope properties that reduce belt stiffness in the width direction of the tread section, because the effects on vertical vibration and longitudinal vibration are contradictory. It turns out that it cannot contribute.

By the way, the interior noise or sprung mass vibration of a vehicle when traveling on an uneven road surface can be expressed as a linear combination of the unsprung mass acceleration in the vertical direction and the longitudinal direction as shown in the following equation.

Xo −aGV + βGH (1 where X.2 Noise inside the vehicle or vibration on the sprung mass G ■: Acceleration when lowering the spring GH: Longitudinal acceleration on the sprung α: Vertical transfer function (contribution rate) for each vehicle β: Vehicle According to the equation (]), depending on the vehicle, there is a transfer function α for internal noise from the lower spring stop vibration, or a transfer function α to the sprung upper vibration i, and the front vibration for the lower spring. The transfer function β to the interior noise or sprung mass vibration from In order to minimize the sprung mass vibration, it is necessary to individually tune both the vertical vibration characteristics and the longitudinal vibration characteristics, which clearly shows that the current situation is problematic and extremely complicated.

In this invention, an additional reinforcing layer made of an organic fiber cord is used in conjunction with the belt to help solve the above problem. As such, when these lower limits are not met, the vertical input from the obstacle O is reduced, but the front and rear force from the ground contact increases, making it impossible to reduce the vertical and longitudinal vibrations at the same time. This is a great candy, and if these upper limits are exceeded, the front and rear force from the ground contact part will decrease, but the vertical input from the obstacle O will increase, so it will still cause vibrations in the vertical and longitudinal directions. The additional reinforcing layer can also be formed between the layers of the belt's metal cord to form a substantially diamond-shaped lattice, subject to appropriate ranges for its width and cord elastic modulus. As a cord arrangement that is divided into two equal parts, it contributes to preventing shear deformation occurring between the layers of the belt, thereby significantly exhibiting the effect of simultaneously reducing vertical and longitudinal vibrations.

Here, the elastic modulus of the cord is calculated by applying a tensile load to the cord and measuring the relationship between the load and elongation.
Extend the rising slope of the curve from the elongation curve to 10%
The load W'fi during elongation is calculated using the following formula.

XIO Cord elastic modulus -.

S: Cross-sectional area of the cord (cup 2) By the way, the elastic modulus of each commonly known scale cord is shown as an example T
Then, it is as follows.

High modulus polyester 600 kg 7mm,
``Rayon 650 9/m'''r':' 5- (Product name 1 3.7tlOkg
7mm" Figure 2 (a) and (the road obstacle Oi already mentioned for bl) The difference in the deformation state of the tread part when it is encompassed by the red part, that is, the difference in the enveloping property, shows that the enveloping property is good. Compared to comparison tires, control tires with poor enveloping properties cause deformation of the tread corresponding to the height of the obstacle, so a larger external force FV must be used in the vertical direction. It is easy to infer that it is better to improve enveloping properties in order to improve vibrations in the vertical direction, but on the other hand, comparative tires with better enveloping properties are less effective in improving longitudinal vibrations due to the following reasons. This is the reason why it is difficult to simultaneously improve vertical vibration and longitudinal vibration.

In other words, the vibration mode of the tire that greatly contributes to the longitudinal rotational force generated when overcoming the obstacle O is shown in Fig. 4(a).
As shown in (b), the external force FH acting in the tangential direction along the ground plane causes an inward translational movement (same ti4
(a)) and rotational vibration around the axis ((b) in the same figure), or in the grounded state, the stiff surface vibration mode is coupled through the ground contact surface as shown in Fig. 1cj), and the degree of this coupling ( degree) determines the magnitude of longitudinal vibration.

In other words, by reducing the degree of coupling, it is possible to improve the longitudinal vibration. This means that the contact 111i KW with the road surface when an obstacle is included is reduced, and therefore, control tires with rather poor enveloping properties can be said to be more advantageous in terms of longitudinal vibration.

In this invention, in order to solve the conflicting relationship in the vertical and longitudinal directions of external forces as excitation forces that act on the tire when passing over an obstacle, the tread stiffness is optimized across the width of the tread. As a result of the inspection J1 from the viewpoint,
Without reducing the rigidity of a part of the tread center, an additional reinforcing layer of woven fiber cords is added to the outside of the outermost layer and the inside of the innermost layer in the radial direction of the belt on both sides of the belt, which is made of multiple metal cord rubberized layers. in direct contact with each belt, and the additional reinforcing layer of the stiffness has already been applied so that the optimal width should be constrained by upper and lower limits in order to simultaneously reduce the vertical and rearward vibrations. The belt shall have an optimal cord elastic modulus, and the diamond-shaped lattice formed by the belt's gold or cord shall be substantially arranged so as to prevent the shear deformation occurring when the metal cord is rubberized Iψ in the direction of its hood. By arranging it in a direction that divides it into two equal parts, l
``We were able to achieve the greatest effect for the purpose of resolving the breach of contract.

Figure 5 shows an example of this. In addition to the 3m portion having the same number as the control tire in Figure 1, 7゜8 is an additional reinforcing layer, and in this example, 5 is a gold R cord on the central circumferential surface. The belt 5 is made up of two rubberized layers, one row of rubberized layers arranged westward at 20° to the right, and another rubberized layer arranged at 20° to the right.
Additional reinforcing layers 7 and 8 made of organic fiber cords having a width of approximately 80% σ) of the width of the tread portion are provided on the outside of the outermost layer in the radial direction of the tire and on the inside of the innermost layer in the bright region. A part of them protrudes slightly from the belt 5.
Place this. The additional reinforcing layers 7, 8 are aromatic holamide fiber cords with a cord elasticity modulus of 30110 kgf/IIIF at θ% elongation + 1500 C1/2).
It consists of a rubberized layer arranged in rows at a driving density of 211.7 lines/25 lines, and the cord direction is substantially the same as the rhombic lattice formed between the metal cord layers of the belt 5 along the circumference of the tread portion in this example. By arranging the cord so as to divide the upper half into two equal parts, and thereby preventing shear deformation occurring between the layers of the metal cord, the enveloping properties at the center of the tread portion and both regions A1111 and A1111 are changed.

FIG. 6 shows the above embodiment, which has a sufficient length in the width direction of the tread portion 1 of the tire and a width of 2 cm in the rolling direction of the tire.
m, height] The vertical and longitudinal rotational force pp values observed when passing over a protrusion 0 cm are plotted against the speed, and are shown by a broken line γ compared to the control tire shown above, which is shown by a solid line. As shown in the figure, both the up and down and front and back directions are simultaneous and have been greatly improved.

In Figures 11a and 11b, the differences in the deformation state in the tread width direction, including the deformation behavior of the tire contact area when passing over protrusion 0, are compared, and the shaded area is the road surface of the tire when it includes protrusion 0. The chain line C indicates the circumferential deflection curve at the center of the tread portion 1, and the chain line S indicates the circumferential deflection curve at the shoulder edge of the tread portion.

The contact shape of the control tire in figure (a) is as follows:
The contact surface phase A near the shoulder of the tread portion 1 is much larger than the contact surface MB near the center of the tread portion. However, in addition to the fact that the effect is almost constant across the entire width of the tread portion 1, the bending moment (m) in the cross-sectional direction from the bead portion 3 and the sidewall 2 is applied as shown in FIG. The deformation of the tread portion 1 in the non-ground contact area exhibits a concave deformation behavior with respect to the road surface as shown by the dotted line. Therefore, the external force f acting on the tire from the protrusion 0 as a vertical excitation force is applied to the tread portion 1.
The distribution in the width direction shows a much larger concave distribution near the shoulder edge than near the center area, and therefore, as mentioned above, the external force as an excitation force in the longitudinal direction is dominated by the external force near the shoulder. That's why.

On the other hand, with a comparative tire whose rigidity is reduced across the entire width of the tread, the external force distribution on the protrusion 0 remains the same, but the overall level is reduced, which is advantageous in terms of vertical vibration, but it also reduces contact with the road surface. The surface phase increases analogously to that shown in FIG. 7(a), and is much more unfavorable for vibration in the backward direction.

However, according to the present invention, without reducing the rigidity at the center of the tread portion 1, organic fiber cords having an elastic modulus within the following range are arranged on both sides of the belt, thereby optimizing the rigidity from the vicinity of the center of the tread portion to the shoulder edge. As shown in Fig. 7b, the enveloping property near the shoulder of the tread section is rather reduced, the contact surface phase near the shoulder that supports longitudinal vibration is reduced, and the center of the tread section is reduced. By increasing the impact effect near the shoulder compared to the shoulder area, it is easier to cause vertical translational movement due to the impact in the shoulder area, and on the other hand, the tread deformation at the valve contact area is caused by a convex deformation with respect to the road surface. By generating this, it is possible to reduce the partial shoulder reaction force in the tread width direction distribution of the external force from the protrusion, which is dominant in the vertical excitation force, and as a result, it is possible to simultaneously reduce the vertical and longitudinal vibrations. It is possible to improve T inside.

Next, FIG. 9 is a cross-sectional view of a tire showing another embodiment of the present invention, in which the edge of the belt 5 is wrapped by a single additional reinforcing layer 9 on both sides of the belt 5, and the organic The direction of the fiber cords is arranged in a direction that substantially bisects the tire along the meridian of the diamond-shaped lattice formed between the metal cord layers of the belt 5, and the shear deformation occurring between the layers of the gold R cord in the shoulder region is also avoided. In the case where the rigidity from the center of the tread portion to the shoulder green is optimized by blocking, the 10th
As shown in the figure, it is possible to simultaneously improve the cutting part of the control tire in the vertical and longitudinal directions, as shown by the broken line δ compared to α.

(Effects of the Invention) As described above, the present invention provides additional reinforcing layers of Arisakura fiber cords on both sides of the belt, which is made up of a plurality of Kanagawa cord rubbers and tension layers. It becomes possible to simultaneously improve the vibration characteristics in the vertical direction and the longitudinal direction at the same time, and it is possible to effectively improve riding comfort.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional example of a belt-reinforced pneumatic rubber tire; Fig. 2 fa) and (b) are comparison diagrams of envelope properties when passing over road obstacles; (b) is a comparison graph of the relationship between the vertical and longitudinal p-pc'') speeds and T due to the difference in envelope properties. A schematic diagram showing the brim mode; FIG. 5 is a sectional view of a T tire showing an embodiment of the present invention; FIGS. 6(a) and (b) are comparison graphs showing the pp reduction effect; a) and (b) are comparative explanatory diagrams of the ground contact behavior and movement when going over a protrusion, Fig. 8 is an explanatory diagram of moment generation behavior in a part of the shoulder, Fig. 9 is a cross-sectional view of the tire of another example, Figure 10 is a comparison graph of the pp reduction effect.]...Tread 8K 2-...Side 1 Diol 8...
...Bead part 4...Carcass 5...Bell)?
, 8.9...Additional reinforcement layer. Patent Applicant Brideston Tire Co., Ltd. Representative Patent Attorney Hideto Sugimura Akira Sugimura Attorney Oki Sugimura Figure 7 (a) Figure 8 Figure 9 Figure 1θ < R) (1+) Speed Speed

Claims (1)

[Scope of Claims] L: A cylindrical tread portion with sidewalls and bead portions on both sides, and a radius that aligns each of these portions with a plane that extends from one bead portion to the other and includes the center circumference of the tread portion. a carcass consisting of at least one brie with cords extending in a plane or a plane intersecting this at a relatively shallow angle; and the width of the tread portion of this carcass.
Across the old enclosure, sandwich the surface including the above central circumference,
A belt-reinforced pneumatic rubber tire reinforced with a belt consisting of at least two rubberized layers in which metal cords are arranged in a direction G that intersects each other at a relatively shallow angle, 25 to 35% of the width of the tread part. an additional reinforcing layer consisting of a rubberized layer of organic fiber cord, which extends slightly beyond the side edges of the belt and is sandwiched between the inner and outer sides of the tire in the radial direction; The organic delicate cord has a modulus of elasticity of 600 at 0% elongation.
A belt-reinforced pneumatic rubber tire with good riding comfort, characterized in that the tire has a diameter of -4000 to 9 f/mm'' and is arranged in a direction that substantially bisects a diamond-shaped lattice formed by metal cords of the belt. 8. The tire according to J or 2, wherein the cords of the additional reinforcing layer are arranged substantially parallel to the central circumference of the tread portion. 4. or the tire according to item 2, wherein the cords of the additional reinforcing layer wrap around the side edges of the belt in a direction substantially perpendicular to the blood including the central circumference of the tread. Elastic modulus at 10% elongation is 200
(1-400(1,&9f/@4112)
4].