JP2011116277A - Tire, rim assembling method of using this tire and assembly of this tire and rim - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire for improving operation stability after assembling the rim, a rim assembling method of such a tire, and an assembly of the tire and the rim for improving the operation stability by using such the tire. <P>SOLUTION: This tire 1 is provided with a tread part 2 formed in an annular shape, a pair of sidewall parts 4 arranged inside in the tire radial direction from both ends of the tread part 2 and a bead part 6 continuing inside in the tire radial direction of the sidewall parts 4, wherein surface roughness in an area α reaching a bead heel 9 of a bead toe 8 of the bead part 6 on the vehicle outside (the OUT side), is larger than surface roughness in an area β reaching the bead heel 9 from the bead toe 8 of the bead part 6 on the vehicle inside (the IN side). The rim assembling method also installs such the tire 1 in the rim 7. The assembly of the tire 1 and the rim 7 is further formed by installing such the tire 1 in the rim 7. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a tire used by being assembled to a rim, and particularly relates to a tire that can improve steering stability. The present invention also relates to a method for assembling such a tire to a rim. The present invention further relates to an assembly of such a tire and a rim.

  In general, with respect to the bead portion of a pneumatic tire, various performances are required such that the rim assembly can be performed quickly, easily and surely, and rim displacement does not occur at the same time as tire loading. In particular, securing the fit between the tire and the rim when assembling the rim is important from the viewpoint of suppressing rim displacement after assembling the rim.

  From the viewpoint of improving the fit, for example, Patent Document 1 discloses a method of assembling a rim after applying a lubricant to a contact region between a bead portion of a tire and a rim.

JP 2005-219556 A

  However, with the recent demand for improved tire performance, further improvements in handling stability are desired. The above prior art is a technique for the purpose of improving the fit of the rim and mainly improving the resistance to rim displacement, and no consideration has been given to the improvement of the steering stability.

  Therefore, the present invention provides a tire that can improve steering stability after assembling a rim, a method for assembling such a tire, and a combination of a tire and a rim that realizes improved handling stability by using such a tire. The purpose is to provide a solid.

  In order to solve the above-mentioned problem, the first invention includes a tread portion formed in an annular shape, a pair of sidewall portions disposed radially inward from both ends of the tread portion, and a tire diameter of the sidewall portion. A tire having a bead portion connected to the inner side in the direction, the tire is assembled to a rim to form a tire wheel, and a region from the bead toe of the bead portion on the outer side of the vehicle to the bead heel in a mounting posture in which the tire wheel is mounted on the vehicle. The tire has a surface roughness greater than the surface roughness in the region from the bead toe to the bead heel of the bead portion inside the vehicle.

  The second invention for solving the above-mentioned problems is a rim assembling method characterized by assembling the tire of the first invention on a rim.

  Furthermore, a third invention for solving the above-mentioned problems is a tire / rim assembly characterized in that the tire according to the first invention is assembled to a rim.

  According to the present invention, by optimizing the bead portion, a tire that can improve the steering stability after assembling the rim, the method of assembling the tire for the rim, and the steering stability using the tire can be achieved. It is possible to provide an improved tire and rim assembly.

1 is a sectional view in the tire width direction of an assembly of a tire and a rim according to the present invention. It is a tire width direction sectional view of the assembly of a conventional example tire and a rim. It is the graph which showed the result of the steering stability in an Example. It is the graph which showed the result of the steering wheel steering angle frequency in an Example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view in the tire width direction of a pneumatic tire (hereinafter simply referred to as “tire”) and rim assembly according to the present invention.

  As shown in FIG. 1, the tire 1 of the present invention includes a tread portion 2 that forms a tread surface of the tire, a pair of sidewall portions 4 that are connected to the outer side in the width direction of the tread portion 2 via a shoulder portion 3, and these A carcass disposed inside the sidewall portion 4 in the tire radial direction, including a pair of bead portions 6A and 6B having a ring-shaped bead core 5, and extending in a toroidal shape between the pair of bead portions 6A and 6B inside the tire, The tire 1 has a conventional tire structure including a belt layer disposed on the outer side in the tire radial direction of the crown region of the carcass. The tire 1 is assembled to the rim 7 (becomes a tire wheel), and has a predetermined internal pressure. Is in a filled state. The “predetermined air pressure” as used herein is defined by industrial standards, standards, etc. that are effective in the area where tires are manufactured, sold, or used, such as JATMA, TRA, ETRTO, etc., and is specified according to the load capacity. Air pressure to be used.

  Further, when the tire 1 of the present invention is mounted on a vehicle as a tire wheel, the surface roughness in the region α from the bead toe 8 to the bead heel 9 of the bead portion 6A on the vehicle outer side (OUT side) with the tire equatorial plane CL as a boundary. Is larger than the surface roughness in the region β from the bead toe 8 to the bead heel 9 of the bead portion 6B on the vehicle inner side (IN side) with the tire equatorial plane CL as a boundary.

  In general, the main external factors that reduce the riding comfort and straight stability of the vehicle, especially the steering stability at a small snake angle, are to vibrate the running vehicle regardless of the vertical or horizontal direction of the vehicle. This is due to road surface irregularities. The inventors compared the case where the unevenness of the road surface collided with the tread portion on the outside of the vehicle with the tire equator plane as a boundary, and the case with the tread portion on the vehicle inside with the tire equator plane as a boundary. Assuming that the size of the unevenness is the same, in most passenger cars, the wheel mounting support part (wheel hub surface) is offset, and the load on the tread part on the outer side of the vehicle is larger than that on the inner side of the vehicle. It was noticed that the vibration was particularly large in the tread portion outside the vehicle. Therefore, if the input to the tread portion of the tire due to the unevenness of the road surface can be substantially biased toward the inside of the vehicle, the vibration input at the tread portion outside the vehicle is suppressed, and as a result, riding comfort is improved. I found out.

  Therefore, the above configuration is adopted, and the surface roughness in the region α from the bead toe 8 to the bead heel 9 of the bead portion 6A on the vehicle outer side (OUT side) with the tire equatorial plane CL as a boundary is defined as the vehicle with the tire equatorial plane CL as a boundary. When the surface roughness in the region β extending from the bead toe 8 to the bead heel 9 of the bead portion 6B on the inner side (IN side) is larger than the friction coefficient between the bead portions 6A and 6B and the rim 7 due to the difference in both surface roughnesses. Due to the difference, the region α on the vehicle outer side (OUT side) fits shallowly with respect to the rim 7, whereas the region β on the vehicle inner side (IN side) fits deeply with respect to the rim 7, and the vehicle outer side (OUT The tire width direction length W1 of the region α on the side) is larger than the tire width direction length W2 of the region β on the vehicle inner side (IN side). Therefore, the tread half width W3 on the vehicle outer side (OUT side) is larger than the tread half width W4 on the vehicle inner side (IN side), and when the tire 1 is viewed in a cross section in the tire width direction, an asymmetric shape is obtained. As a result, the input to the tread portion of the tire due to the unevenness of the road surface can be substantially biased to the inside of the vehicle, and the vibration input at the tread portion on the outside of the vehicle is suppressed, so that riding comfort is improved. In particular, steering stability during straight traveling is improved, and overall steering stability on dry road surfaces and wet road surfaces is improved. In addition, if the above configuration is adopted according to the present invention, the lateral force fluctuation of the tire caused by disturbance input such as road step and undulation is reduced, and the vehicle wobble is reduced. The frequency of correction is reduced. Normally, the manufacture of a tire having an asymmetric shape requires changing the vulcanization mold or changing the belt structure accurately, and the manufacture itself is difficult. The tire can be asymmetrical only by controlling the surface roughness in the region from the 6A, 6B bead toe 8 to the bead heel 9, which is preferable from the viewpoint of production cost and labor.

  As mentioned above, although demonstrated based on the example of illustration, this invention is not limited to the above-mentioned embodiment, It is possible to change suitably within the description range of a claim.

  Next, a conventional tire (conventional tire) in which the surface roughness in the region from the bead toe of the bead part to the bead heel is the same in the left and right bead parts, and the bead toe of the bead part on the outside of the vehicle according to the present invention. Since the tires of the examples (example tires) in which the surface roughness in the region leading to the vehicle is larger than the surface roughness in the region from the bead toe of the bead portion inside the vehicle to the bead heel were used for various performance evaluations, This will be described below. These tires are all radial tires for passenger cars having a tire size of 205 / 55R16. The above-mentioned various tires were assembled on a rim of size 6.5 J × 16, and after applying an air pressure of 230 kPa (relative pressure) inside, they were mounted on a vehicle and subjected to various evaluations shown below.

As shown in FIG. 2, the conventional tire has a symmetrical shape with the tire equatorial plane as a boundary even after the rim is assembled. Further, the surface roughness in the region from the bead toe to the bead heel of both bead portions on the vehicle inner side and the vehicle outer side is the same.
As shown in FIG. 1, the example tire has an asymmetric shape with the tire equatorial plane as a boundary after assembling the rim. Further, the surface roughness in the region from the bead toe to the bead heel of the bead portion outside the vehicle is larger than the surface roughness in the region from the bead toe to the bead heel of the bead portion inside the vehicle.

  Steering stability on dry roads was evaluated by a professional driver using the above vehicle on a test circuit course in a straight line under various conditions, and using a feeling of straightness and disturbance stability as an index. . The evaluation was performed by calculating and comparing the relative values of the example tires with the result of the conventional tire as the reference value 100. In addition, it shows that it is excellent in steering stability, so that a numerical value is large. The measurement results are shown in FIG.

  In the evaluation of steering stability, the steering angle frequency of the steering wheel was also evaluated. The steering angle of the steering wheel is determined by the professional driver driving the vehicle straight ahead at 100 km / h on the test circuit course and using the steering angle (steering angle) as the steering angle meter. The measured steering angle was converted into frequency and evaluated. The evaluation was performed by calculating and comparing the relative values of the example tires with the result of the conventional tire as the reference value 100. In addition, the smaller the numerical value, the less the steering angle frequency of the steering wheel, and the better the steering stability. The measurement results are shown in FIG.

  As is clear from the results of FIG. 3, the steering stability on the dry road surface was significantly improved in the example tires as compared to the conventional tires. Further, as is apparent from the results of FIG. 4, the steering angle frequency of the steering wheel was also lower in the example tires than in the conventional tires.

  Thus, according to the present invention, a tire capable of improving the handling stability after assembling the rim, a method of assembling the rim of such a tire, and a tire and rim assembly in which the handling stability is improved by using such a tire are provided. It became possible to provide.

DESCRIPTION OF SYMBOLS 1 Tire 2 Tread part 3 Shoulder part 4 Side wall part 5 Bead core 6A, 6B Bead part 7 Rim 8 Bead toe 9 Bead heel

Claims (3)

In a tire including a tread portion formed in an annular shape, a pair of sidewall portions disposed on the inner side in the tire radial direction from both ends of the tread portion, and a bead portion continuous on the inner side in the tire radial direction of the sidewall portion. ,
The tire is assembled to the rim to form a tire wheel, and in a mounting posture in which the tire wheel is mounted on the vehicle, the surface roughness in the region from the bead toe of the bead portion on the outside of the vehicle to the bead heel is from the bead toe of the bead portion on the inside of the vehicle. A tire characterized by being larger than the surface roughness in the region leading to the bead heel.   A rim assembling method comprising assembling the tire according to claim 1 to a rim.   A tire and rim assembly comprising the tire according to claim 1 assembled to a rim.

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