Evaluation method for pneumatic tires and system thereof
An evaluation method for pneumatic tires and a system thereof, is provided, capable of appropriately evaluating an adverse effect, such as deterioration, of tire temperature by expressing severity of a temperature imposed on a member of tire made of rubber or the like in quantitative and convenient manners. Detection counts are calculated for each detected temperature according to a detection counts calculating unit 102 based on information of temperatures of pneumatic tires detected by a temperature sensor of a temperature detector 101 . Temperature severity numbers of the pneumatic tires are calculated from a computing equation by a severity calculating unit 104 based on the detection counts and contribution coefficients of deterioration of tire rubber with temperatures stored in a contribution coefficient storage 103 as parameters. Using the calculated temperature severity number, a determination unit 105 determines thermal deterioration of the tire.
1. An evaluation method for pneumatic tires which comprises the steps: a step of inputting information of pneumatic tire temperatures sequentially detected for each predetermined time by a temperature sensor into a system and a step of making the system evaluate an adverse effect of the pneumatic tire temperatures based on the information, characterized in that the system performs the following operations:
determining a total detection counts N of detected temperatures and a count ni of temperatures detected for each detected temperature Ti;
substituting a contribution coefficient ki which is constituted of power function of temperatures and is associated with a state change in a tire member previously given using temperatures as parameters and a rate β into a computing equation TSN=Σ(Ti×ni×ki/N)×β to calculate a temperature severity number TSN of the pneumatic tire; and
evaluating an adverse effect of a tire temperature using the calculated temperature severity number TSN.
2. The evaluation method for pneumatic tires according to claim 1 , characterized in that the contribution coefficient ki constituted of power function of temperatures is a rate set based on the Arrhenius' equation of reaction rate.
3. The evaluation method for pneumatic tires according to claim 2 , characterized in that the adverse effect of a temperature is deterioration and the state change in a tire member is deterioration of the tire member.
4. The evaluation method for pneumatic tires according to claim 3 , characterized in that a value between 1/100 and 100 inclusive except 0 is used as the rate β.
5. The evaluation method for pneumatic tires according to claim 3 , characterized in that a detectable temperature range is divided into a plurality of temperature zones, the contribution coefficient ki is previously set for each temperature zone, and the contribution coefficient ki corresponding to a temperature zone relative to a detected temperature Ti in a predetermined temperature zone is used for the calculation.
6. The evaluation method for pneumatic tires according to claim 1 , characterized in that the adverse effect of a temperature is deterioration and the state change in a tire member is deterioration of the tire member.
7. The evaluation method for pneumatic tires according to claim 6 , characterized in that a value between 1/100 and 100 inclusive except 0 is used as the rate β.
8. The evaluation method for pneumatic tires according to claim 6 , characterized in that a detectable temperature range is divided into a plurality of temperature zones, the contribution coefficient ki is previously set for each temperature zone, and the contribution coefficient ki corresponding to a temperature zone relative to a detected temperature Ti in a predetermined temperature zone is used for the calculation.
9. An evaluation system for pneumatic tires, evaluating an adverse effect of a temperature of a pneumatic tire based on information of temperatures of the pneumatic tire detected by a temperature sensor, characterized by comprising:
temperature detection means which include the temperature sensor, detect temperatures Ti of the pneumatic tire and output information of the temperatures;
contribution coefficient storage means previously storing, for each temperature Ti, contribution coefficients ki which are constituted of a power function and are associated with a state change in a tire member with temperatures as parameters;
detection counts calculating means for calculating a count ni of temperatures detected for each detected temperature Ti and a total detection counts N of detected temperatures based on the detected temperature information;
temperature severity number calculating means of substituting the total detection counts N, the count ni of temperatures detected, the contribution coefficient ki and the rate β into a computing equation TSN=Σ(Ti×ni×ki/N)×β to calculate a temperature severity number TSN of the pneumatic tire; and determination means of determining an adverse effect of a tire temperature using the calculated temperature severity number TSN.
10. The evaluation system for pneumatic tires according to claim 9 , characterized in that the contribution coefficient ki constituted of power function of temperatures is a rate set based on the Arrhenius' equation of reaction rate.
11. The evaluation system for pneumatic tires according to claim 10 , characterized in that the adverse effect of a temperature is deterioration and the state change in a tire member is deterioration of the tire member.
12. The evaluation system for pneumatic tires according to claim 11 , characterized in that a value between 1/100 and 100 inclusive except 0 is used as the rate β.
13. The evaluation system for pneumatic tires according to claim 11 , characterized in that the contribution coefficient storage means have the contribution coefficient ki previously set for each of a plurality of temperature zones obtained by dividing a detectable temperature range, and that temperature severity number calculating means performs the calculation using a contribution coefficient ki corresponding to a temperature zone relative to a detected temperature Ti in a predetermined temperature zone.
14. The evaluation system for pneumatic tires according to claim 11 , characterized in that the temperature detection means measure any of a tire internal temperature, a tire internal air temperature and a tire surface temperature with the temperature sensor.
15. The evaluation system for pneumatic tires according to claim 11 , characterized by including alarm means of, if the temperature severity number TSN is above a predetermined value, determining tire deterioration to be above a specified value, and issuing an alarm.