MXPA98001397A

MXPA98001397A - Pneumatic rim that has an improved sequence of pa

Info

Publication number: MXPA98001397A
Application number: MXPA/A/1998/001397A
Authority: MX
Inventors: Janusz Wesolowski Piotr
Original assignee: The Goodyear Tire & Rubber Company
Priority date: 1995-09-05
Filing date: 1998-02-20
Publication date: 1998-10-23

Abstract

The present invention relates to a rim provided with a tread band having a plurality of load bearing elements positioned around the circumference of the rim, said tread band having a sequence of steps comprising: (a) 55, 67, 69, 73, 76, 79, 85, 98 total steps, (b) only five different step lengths and the lowest indivisible elements used for the five step lengths are 7-8-9-10 and 11; (c) a ratio of the longest step length to the shortest step length that varies from 1.57 to 1.58, and (d) there is a constant increase in the length of steps in the five different step lengths as they progress from the shorter step length towards the longer step length, where the 55 double step consist of 8 9 11 9 7 7 10 11 8 7 7 8 9 10 7 9 7 8 7 8 7 9 9 8 8 11 11 9 10 10 7 7 9 8 10 11 7 8 9 9 10 9 11 10 8 8 7 7 8 10 11 10 8 7 7, where the 67 total steps consist of have of: 8 10 11 8 7 7 8 10 11 9 7 7 8 7 7 10 9 8 10 9 11 8 8 8 7 11 9 11 7 8 7 10 7 10 7 8 9 10 11 9 9 8 10 7 7 7 7 7 9 10 11 8 10 10 11 8 8 7 8 8 9 10 7 7 7 9 8; eb where the 69 total steps consist of 10 9 10 9 11 9 11 8 8 7 7 10 9 9 8 7 7 7 8 9 9 10 10 8 7 7 9 9 11 8 8 7 7 7 7 10 8 8 8 7 10 11 10 9 8 8 7 10 7 7 8 8 10 10 9 8 7 10 10 9 9 9 8 8 9 7 7 7 9; where the total 73 steps consist of 7 7 7 8 9 9 8 7 9 11 9 10 10 10 10 7 8 7 8 7 7 7 7 11 9 8 9 8 8 9 11 10 8 7 7 7 7 8 11 9 7 7 8 9 9 10 10 8 9 7 8 9 7 7 7 7 9 8 9 11 8 7 7 8 8 9 10 8 8 11 10 8 9, where the total 76 steps consist of 7 7 8 8 8 11 9 10 10 9 9 1 8 7 8 8 9 11 10 9 8 7 8 8 9 8 7 10 9 11 10 9 8 7 8 8 9 10 8 10 9 7 8 7 7 7 8 10 8 11 9 11 9 10 8 8 8 7 7 8 9 11 8 10 7 8 9 11 11 10 9 8 7 7 7, where the total 79 steps consist of 8 9 10 7 7 8 8 11 11 10 9 9 8 7 7 7 7 7 8 10 11 8 8 9 10 11 10 9 8 7 7 7 8 9 9 8 10 11 9 10 8 7 7 8 9 9 10 11 9 8 7 8 8 7 9 8 10 9 11 8 8 7 7 7 7 8 9 10 10 10 9 11 10 8 8 8 9 8 10; in d The 85 total steps consist of 9 10 10 11 9 10 11 9 8 7 7 7 7 7 8 9 9 10 8 8 7 8 7 9 8 10 9 9 8 8 7 9 10 8 11 9 7 8 8 7 8 9 10 10 10 10 9 8 8 7 9 9 8 9 9 10 8 8 10 9 11 8 8 7 7 7 7 8 9 8 9 9 11 10 9 8 9 9 7 7 8 7 8 8 9, and where the 98 total steps consist of 7 8 8 7 8 10 10 9 10 9 8 7 8 9 10 11 10 10 8 7 7 8 9 11 9 8 10 7 8 7 8 8 9 11 9 10 9 8 7 10 10 10 8 7 7 7 8 9 9 9 9 9 8 7 7 7 9 11 9 8 8 10 9 7 8 8 10 9 8 7 7 7 8 8 11 10 9 11 10 8 9 7 7 8 10 10 11 8 8 9 8 9 10 9 8 7 7

Description

PNEUMATIC RIM THAT HAS AN IMPROVED SEQUENCE OF STEPS BACKGROUND OF THE INVENTION The present invention relates to a pneumatic tire, more particularly to a tread pattern for a pneumatic tire. As a tire travels on a surface, a movement of the air occurs, creating an audible sound. For any given pattern of tread, a certain amount of acoustic energy is produced. While two different tread patterns can produce the same amount of acoustic energy, the noise produced by each can have drastically different effects on people. A tire can have a rough and unpleasant sound and another, a very acceptable sound. The difference between the two sounds is in their frequency spectrum and can result in a different subjective audible reaction. The condition where the generated sound is dominated by a single frequency and its harmony, that is, a majority of the generated sound is concentrated in a very small frequency range of the sound spectrum, which is inconvenient. This situation is psychologically disturbing to a listener, creating an uncomfortable sensation. Additionally, in addition to being irritating, total sounds can be perceived at great distances and require more sound-proof material, compared to non-total sounds. If a given concentration of sound energy can be spread over a wider range of frequency, the inconvenient shape of the sound would be reduced. Several methods have been suggested in the past to reduce the objectionable noise generated by the tires, by disseminating the energy produced over the frequency range. For example, the patents of E. U. A., Nos. 4,327,792 and 4,474,223, disclose a method for disseminating noise by load bearing elements of a tread of the rim. This is achieved by designing load carrying elements according to a five-stage procedure, to determine the maximum number of repeated cycles of the design, which can be used, selecting the maximum step ratio, determining the appropriate number of harmonic segments in the which the tread can be divided, determining the size of each harmonic segment and the number of design cycles for each harmonic segment and finally arranging the various design cycles in each of the harmonic segments, so that the wavelength of the predominant frequency of modulation of the segment corresponds to the length of the formula of that segment.

SUMMARY OF THE INVENTION The present invention relates to a rim provided with a tread band having a plurality of load bearing elements, placed above the circumference of the rim. This tread has a step sequence comprising: (a) from 55 to 98 total steps; (b) only five different pitch lengths and the smallest indivisible integers used for the five pitch lengths are 7-8-9-10 and 11; (c) a ratio of the longest step length to the shortest step length that varies from 1.57 to 1.58; and (d) there is a constant increase in step length at the five different pitch lengths, as it progresses from the shortest step length to the longest step length.

Detailed Description of the Drawings Figure 1 is a graphic illustration of the Analysis Harmonic pulse function for a tire treadmill having 79 steps, obtained in accordance with the present invention and using the sequence of steps disclosed herein. Figure 2 is a graphical illustration of the Harmonic Analysis of the pulse function for a tire treadmill having 79 steps, obtained according to the patent of E. U. A., No. 4,474,223.

Detailed Description of the Invention As used herein and in the claims, the following terms are intended to mean: "Step", also known as "design cycle", means a section of the tread, in the circumferential direction, which is repeated around the outer circumference of the rim. Typically, a step contains a load carrying element and an adjacent slot, which separates attachments that carry load on a tread of the rim. However, the limits of a pitch in the circumferential direction may bisect a load carrying element or the adjacent slot, depending on the point at the limit in the axial direction. Even so, each step generally contains the total of at least one item carrying charge and at least one slot, but may consist of two fractions which total one item or full slot. "Step ratio" means the ratio of the length of the longest design cycle to the shortest design cycle length. "Sequence of passage" means the particular arrangement of different segments of the length of the design cycle, around the complete circumference of the tread. "Pneumatic tire" means a mechanical laminated device, generally of toroidal configuration (usually an open bull shape), having flanges, a fabric or framework layer and a tread band. The pneumatic tires of the present invention have an improved passage sequence. The use of these sequences in the tires results in improved subjective properties of the noise. The ratio of the length of the longest step to the shortest step length varies from 1.57 to 1.58. Preferably, the ratio is 1,571. In the sequences of the steps used in the present invention, the smaller indivisible integers used for the step sequences, which have four step lengths, are 7, 8, 9, 10 and 11. There is a constant increase in step length in the five different lengths of the step, as one progresses from the shortest step length to the longest step length. For example, for a step length ratio of 7, 8, 9, 10 and 11, there is a constant increase of 1. There are eight step sequences which are the preferred embodiments of the present invention. In terms of these step relationships, the following sequences are described. The sequences below are interpreted in terms of a closed loop (like a tire) and any step can start the sequence or finish the sequence, as long as the order of the sequence is maintained. The first sequence of steps consists of 55 total steps. This sequence of steps is as follows: 8 9 11 9 7 7 10 11 8 7 7 8 9 10 7 9 7 8 7 8 7 9 9 8 8 11 11 9 10 10 7 7 9 8 10 11 7 8 9 9 9 11 10 8 8 7 7 8 10 11 10 8 7 7 The second preferred sequence of steps has a total of 67 steps and is as follows: 8 10 11 8 7 7 8 10 11 9 7 7 8 7 7 10 9 8 10 9 11 8 8 8 7 11 9 11 7 8 7 10 7 10 7 8 9 10 11 9 9 8 10 7 7 7 7 7 9 10 11 8 10 10 11 8 8 7 8 8 9 10 7 7 7 9 8.

The third preferred sequence of steps consists of total steps and is as follows: 9 10 9 11 9 11 8 8 7 10 9 9 8 7 7 7 8 9 10 10 8 7 7 9 9 11 8 7 7 7 7 10 8 8 8 7 11 10 9 8 8 7 10 7 7 8 10 10 9 8 7 10 10 9 9 8 8 9 7 7 7 9.

The fourth preferred sequence of steps consists of total steps and is as follows: 7 7 8 9 9 8 7 9 11 10 10 10 10 7 8 7 8 7 7 7 11 9 8 9 8 8 9 10 8 7 7 7 7 8 11 9 7 8 9 9 10 10 8 9 7 9 7 7 7 7 9 8 9 11 7 7 8 8 9 10 8 8 11 The fifth preferred sequence of steps consists of 76 total steps and is as follows: 7 7 8 8 8 11 9 10 10 9 9 11 8 7 8 8 8 9 11 10 9 8 7 8 8 9 8 7 10 9 Ll 10 9 8 7 8 8 9 10 8 LO 9 7 8 7 7 7 8 10 8 Ll 9 11 9 10 8 8 8 7 7 8 9 11 8 10 7 8 9 11 11 LO 9 8 7 7 7.

The sixth preferred sequence of steps consists of 79 total steps and it is as follows: 8 9 10 7 7 8 8 11 11 10 9 9 8 7 7 7 7 7 8 10 11 8 8 9 10 11 10 9 8 7 7 7 8 9 9 8 10 11 9 10 8 7 7 8 9 9 10 11 9 8 7 8 8 7 9 8 10 9 11 8 8 7 7 7 7 8 9 10 10 10 9 11 10 8 8 8 9 8 10.

The seventh preferred sequence of steps consists of total steps and is as follows: 9 10 10 11 9 10 11 9 8 7 7 7 7 7 8 9 9 10 8 8 7 8 7 9 8 10 9 9 8 8 7 9 10 8 11 9 7 8 8 7 8 9 10 10 10 10 9 8 8 7 9 9 8 9 9 10 8 8 10 9 Ll 8 8 7 7 7 7 8 9 8 9 9 11 10 9 8 9 9 7 7 8 7 8 8 9.

The eighth preferred sequence of steps consists of total steps and is as follows: 7 8 8 7 8 10 10 9 10 9 8 7 8 9 10 11 10 10 8 7 7 8 9 11 9 8 10 7 8 7 8 8 9 11 9 10 9 8 7 10 0 10 8 7 7 7 8 9 9 9 9 9 8 7 7 7 9 11 9 8 8 10 9 7 8 8 10 9 8 7 7 7 8 8 11 10 9 11 10 8 9 7 7 8 10 10 11 8 8 9 10 9 8 7 7 9.

The rims of the present invention can be for passenger vehicles, multipurpose vehicles, light trucks and medium trucks. According to the present invention, what determines the length of the individual design cycles in a given rim are the requirements of (a) there are only 55 to 98 total steps, (b) only five different pitch lengths, (c) ) the specific sequence of the step, (d) the five length ratios of the design cycle and (e) the known outer circumference of the rim. To determine how long each design cycle will be for a rim of a given external circumference, one takes the sum of all the integers in the sequence of steps, expressed in terms of relations. For example, from the previous sequence of 55 steps, the sum would be 475 (7 x 15 + 8 x 13 + 9 x 11 + 10 x 9 + 11 x 7). For a rim of size P195 / 65R15, the outer circumference will be of 2001 mm. If one divides the outer circumference of 2001 mm. by 475, you get 4,213. One takes this number, 4.213, and multiplies it by 7, 8, 9, 10 and 11, to supply the respective lengths of the steps, 29.49 mm. , 33.704 mm. , 37,917 mm. , 42.13 mm. and 46,343 mm. EXAMPLE 1 Computer simulation tests were carried out, comparing the Harmonic Analysis of the impulse function of the treads of the tires with the sequences of steps, arranged according to the present invention, versus the sequences of steps of according to the US patent, No. 4,474,223. Figure 1 is a graphic illustration of the Analysis Harmonic impulse function, which uses the sequence of steps consisting of 79 individual steps, which are as follows: 8 9 10 7 7 8 8 11 11 10 9 9 8 7 7 7 7 7 8 10 11 8 8 9 10 11 10 9 8 7 7 7 8 9 9 8 10 11 9 10 8 7 7 8 9 9 10 11 9 8 7 8 8 7 9 8 10 9 11 8 8 7 7 7 7 8 9 10 10 10 9 11 10 8 8 8 9 8 10.

Figure 2 is a graphical illustration of the Harmonic Analysis of the pulse function, which uses a sequence of steps consisting of 79 individual steps, according to the patent of E. U. A., No. 4,474,223, and which are as follows: 7 7 7 7 7 7 7 7 9 9 9 9 9 9 9 9 11 11 11 11 11 11 11 11 9 9 9 7 7 7 7 7 7 9 9 9 9 9 9 11 11 11 11 11 11 9 9 9 7 7 7 7 9 9 9 9 11 11 11 11 9 9 7 7 7 7 7 9 9 9 9 9 11 11 11 11 11 9 9. When comparing Figures 1 and 2, we see that the Fourier spectrum of the impulse function for the tread of the rim, where the sequence of steps is arranged, according to the present invention (Figure 1) has more flat harmonic components than the sequence of steps in Figure 2. The flatter harmonic components produce a reduced noise of the rim, as this rim makes contact with the road surface. The quality of the calculated Fourier spectrum can also be expressed by a maximum Normalized Amplitude. It is clearly visible from the comparison of Figures 1 and 2, that the maximum Normalized Amplitude, calculated from the step sequence (s), according to the present invention, is smaller than that according to the US patent. , No. 4,474,223. Therefore, it has been determined that a rim having the steps disposed in accordance with the present invention has a reduction in tread noise, as the rim contacts the road surface. In particular, there is a reduction of the maximum amplitude in the 200 harmonic spectrum by more than 20 percent.

Claims

CLAIMS 1. A rim provided with a tread, having a plurality of load bearing elements, placed around the circumference of the rim, said band having a sequence of steps characterized by: (a) from 55 to 98 steps totals; (b) only five different pitch lengths and the smallest indivisible integers used for the five pitch lengths are 7-8-9-10 and 11; (c) a ratio of the longest step length to the shortest step length that varies from 1.57 to 1.58; and (d) there is a constant increase in step length at the five different pitch lengths, as it progresses from the shortest step length to the longest step length.
2. The rim of claim 1, characterized in that the sequence of steps consists of 55 total steps and consists of: 8 9 11 9 7 7 10 11 8 7 7 8 9 10 7 9 7 8 7 8 7 9 9 8 8 11 11 9 10 10 7 7 9 8 10 11 7 8 9 9 10 9 11 10 8 8 7 7 8 10 11 10 8 7 7
3. The rim of claim 1, characterized in that the sequence of steps consists of 67 total steps and consists of: 8 10 11 8 7 7 8 10 11 9 7 7 8 7 7 10 9 8 10 9 11 8 8 8 7 11 9 11 7 8 7 10 7 10 7 8 9 10 11 9 9 8 10 7 7 7 7 7 9 10 11 8 10 10 11 8 8 7 8 8 9 10 7 7 7 9 8.
4. The rim of claim 1, characterized in that the sequence of steps consists of 69 total steps and consists of: 10 9 10 9 11 9 11 8 8 7 7 10 9 9 8 7 7 7 8 9 9 10 10 8 7 7 9 9 11 8 8 7 7 7 7 10 8 8 8 7 10 11 10 9 8 8 7 10 7 7 8 8 10 10 9 8 7 10 10 9 9 9 8 8 9 7 7 7 9.
5. The rim of claim 1, characterized in that the sequence of steps consists of 73 total steps and consists of: 7 7 7 8 9 9 8 7 9 11 9 10 10 10 10 7 8 7 8 7 7 7 7 11 9 8 9 8 8 9 11 10 8 7 7 7 7 8 11 9 7 7 8 9 9 10 10 8 9 7 8 9 7 7 7 7 9 8 9 11 8 7 7 8 8 9 10 8 8 11 10 8 9.
The rim of claim 1, characterized in that the sequence of steps consists of € 7 > Total steps and consists of: 7 7 8 8 8 11 9 10 10 9 9 11 8 7 8 8 8 9 11 10 9 8 7 8 8 9 8 7 10 9 11 10 9 8 7 8 8 9 10 8 10 9 7 8 7 7 7 8 10 8 11 9 11 9 10 8 8 8 7 7 8 9 11 8 10 7 8 9 11 11 10 9 8 7 7 7.
7. The rim of claim 1, characterized in that the sequence of steps consists of 79 total steps and consists of: 8 9 10 7 7 8 8 11 11 10 9 9 8 7 7 7 7 7 8 10 11 8 8 9 10 11 10 9 8 7 7 7 8 9 9 8 10 11 9 10 8 7 7 8 9 9 10 11 9 8 7 8 8 7 9 8 10 9 11 8 8 7 7 7 7 8 9 10 10 10 9 11 10 8 8 8 9 8 10.
8. The rim of claim 1, characterized in that the sequence of steps consists of 85 total steps and consists of: 9 10 10 11 9 10 11 9 8 7 7 7 7 7 8 9 9 10 8 8 7 8 7 9 8 10 9 9 8 8 7 9 10 8 11 9 7 8 8 7 8 9 10 10 10 10 9 8 8 7 9 9 8 9 9 10 8 8 10 9 11 8 8 7 7 7 7 8 9 8 9 9 11 10 9 8 9 9 7 7 8 7 8 8 9.
9. The rim of claim 1, characterized in that the sequence of steps consists of 98 total steps and consists of: 7 8 8 7 8 10 10 9 10 9 8 7 8 9 10 11 10 10 8 7 7 8 9 11 9 8 10 7 8 7 8 8 9 11 9 10 9 8 7 10 10 10 8 7 7 7 8 9 9 9 9 9 8 7 7 7 9 11 9 8 8 10 9 7 8 8 10 9 8 7 7 7 8 8 11 10 9 11 10 8 9 7 7 8 10 10 11 8 8 9 8 9 10 9 8 7 7 9. 7 9 8 8 9 10 11 9 10 7 10 7 7 7 7 7 9 10 10 8 11 10 11 8 8 8 7 9 8 10 7 7 7 9 8 9 10 10 8 8 7 7 10 11 9 7 7 8 7 7 10 9 8 10 9 11 8 8 8 7 9 10 11 8 8 7 19.
10. The rim of claim 1, characterized in that the rim is for a passenger vehicle.
11. The rim of claim 1, characterized in that the rim is for a multi-purpose vehicle.
12. The rim of claim 1, characterized in that the rim is for a light truck.
13. The rim of claim 1, characterized in that the rim is for a medium truck.