JP2008298723A - Method of evaluating deterioration in pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of evaluating deterioration in pneumatic tire, capable of surely evaluating the affection of deterioration due to the temperature or oxidation of the tire by quantitatively and conveniently indicating the severity of the temperature or oxidation affecting on the member, such as the rubber of the tire. <P>SOLUTION: The method of evaluating deterioration converts pneumatic pressure which is the measurement result of a pneumatic pressure reduction calculating part 103 into the temperature converted pneumatic pressure which is the pneumatic pressure at the reference temperature, and from the temperature converted into the pneumatic pressure, the pneumatic pressure variations rate per unit time are calculated, a severity calculation part 104 determines that the reduction in the pneumatic pressure is due to natural leakage, if the value of the pneumatic pressure variation rate is less than 0. The pneumatic pressure reduction amount per unit time P is successively integrated, and the integrated value is made oxidation severity; and by comparing with the plurality of predetermined thresholds of the oxidation severities with the predetermined intervals set by the determination part 105, the level of the degradation of the pneumatic tire is determined. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for evaluating deterioration of a pneumatic tire for evaluating the influence of temperature deterioration, oxidation deterioration, etc. of the pneumatic tire.

  Conventionally, as a method or an apparatus for evaluating the deterioration of a pneumatic tire, for example, a method for predicting a change with time of a tire disclosed in Japanese Patent Laid-Open No. 2005-47295 (Patent Document 1), Re-published WO 2003-100370 (Patent) A tire thermal deterioration detection sensor disclosed in Document 2) and a vehicle diagnostic system disclosed in Japanese Patent Laid-Open No. 2005-227141 (Patent Document 3) are known.

  The tire temporal change prediction method disclosed in Patent Document 1 defines a tire model formed by disassembling a tire into a number of elements, and an energy (including thermal energy and elapsed time) model applied to the tire model, The stress calculation including the fracture parameter and the drag calculation against the fracture force are performed, and the tire timing change (life) is predicted based on the physical quantity of these calculation results. According to this method, the time-varying performance of the tire can be predicted by comparing the tire destruction parameter and the drag, and analysis according to the use state of the tire can be made possible.

  The tire thermal deterioration detection sensor disclosed in Patent Document 2 is provided in a required portion of the tire, and forms a magnetic closed circuit, and a magnetic sensor detects a leakage magnetic field from the magnetic circuit structure. And has a characteristic that the leakage magnetic field increases when the temperature rises or the thermal deterioration proceeds.

  According to this sensor, the magnetic characteristics of the magnetic circuit component or the composite magnet are changed by the magnetic sensor that detects the leakage magnetic field from the magnetic circuit component provided in the required part of the tire or the magnetic field from the composite magnet. On the other hand, the magnetic characteristics of the magnetic circuit component or the composite magnet are configured to change depending on the temperature of the required portion of the tire or the degree of thermal degradation. , To know the temperature or degree of thermal degradation of the required tire part, to detect abnormalities in the degree of temperature or thermal degradation and to alert the driver, contributing to safe vehicle operation Can do.

  The vehicle diagnosis system disclosed in Patent Document 3 is a system for diagnosing deterioration or consumption of consumables of a vehicle including a tire and displaying the result on the screen of an in-vehicle display. Data such as the average temperature and the maximum temperature of the tire in one day of vehicle travel are included.

According to this system, the diagnosis result of the vehicle consumables is not simply displayed on the screen, and the driving behavior of the driver is not simply displayed on the screen. The driver's driving behavior is added to the diagnostic elements and displayed on the screen, so the driver can intuitively know the causality of the driver's driving behavior and the diagnostic result of the vehicle consumables. , You can try to drive safely.
JP-A-2005-47295 Reissue WO2003-100370 JP 2005-227141 A

  When evaluating changes in conditions such as deterioration of pneumatic tires, temperature changes and oxidation of tire members such as rubber are a major factor. However, in the method and apparatus described above, the temperature and oxidation severity of tire members are severe. Is not expressed quantitatively and conveniently, there is a problem that it is difficult to objectively grasp the influence of deterioration, oxidation deterioration, and the like due to tire temperature change.

  The present invention has been made in view of the above-mentioned problems, and the object of the present invention is to quantitatively and conveniently represent the temperature and oxidation severity applied to a member such as a tire rubber and the tire temperature and oxidation. An object of the present invention is to provide a method for evaluating deterioration of a pneumatic tire that can accurately evaluate the influence of deterioration and the like due to the deterioration.

  In order to achieve the above-mentioned object, the present invention inputs information relating to the pneumatic pressure and temperature of a pneumatic tire sequentially detected at predetermined intervals by a pneumatic sensor and a temperature sensor to the device, and based on the information by the device, A deterioration evaluation method for a pneumatic tire for evaluating deterioration of a pneumatic tire enclosing a gas having an oxygen concentration of 5% or more, wherein the apparatus converts an air pressure of a measurement result to an air pressure at a predetermined reference temperature based on the information. The air pressure change rate per unit time is calculated from the temperature converted air pressure, and when the air pressure change rate value is less than 0, the air pressure decrease amount P per unit time is sequentially integrated. In addition, the integrated value of the air pressure decrease amount P is defined as oxidation severity, and the deterioration of a pneumatic tire that evaluates tire degradation using the oxidation severity is inferior. We propose an evaluation method.

  According to the method for evaluating deterioration of a pneumatic tire of the present invention, the device converts the measured air pressure into a temperature converted air pressure that is an air pressure at a predetermined reference temperature, and the air pressure change rate per unit time from the temperature converted air pressure. When the value of the air pressure change rate is less than 0, the air pressure decrease amount P per unit time is sequentially integrated, and the integrated value of the air pressure decrease amount P is regarded as oxidation severity, and tires are obtained using this oxidation severity. Is evaluated for degradation.

  In order to achieve the above-mentioned object, the present invention inputs information related to the pneumatic pressure and temperature of a pneumatic tire sequentially detected by a pneumatic sensor and a temperature sensor every predetermined time to the apparatus, and based on the information by the apparatus. A pneumatic tire deterioration evaluation method for evaluating deterioration of a pneumatic tire in which a gas having an oxygen concentration of 5% or more is sealed, wherein the device converts an air pressure of a measurement result to a predetermined reference temperature based on the information. The air pressure change rate per unit time is calculated from the temperature converted air pressure, and when the air pressure change rate value is less than 0, the air pressure decrease amount P per unit time is calculated. A value obtained by sequentially integrating the values as oxidation severity and, based on the information, a value obtained by sequentially integrating the temperatures of the measurement results is referred to as temperature severity. Of calculated total deterioration index from the severity and the temperature severity, proposes a degradation evaluation method of the pneumatic tire to evaluate the degradation of the tire by using the total degradation index.

  According to the method for evaluating deterioration of a pneumatic tire of the present invention, the device converts the measured air pressure into a temperature converted air pressure that is an air pressure at a predetermined reference temperature, and the air pressure change rate per unit time from the temperature converted air pressure. When the value of the air pressure change rate is less than 0, the value obtained by sequentially integrating the air pressure decrease amount P per unit time is regarded as the oxidation severity, and the value obtained by sequentially integrating the measured temperature is the temperature severity. Thus, a total deterioration index is obtained from the oxidation severity and the temperature severity, and the tire deterioration is evaluated using the total deterioration index.

  According to the method for evaluating deterioration of a pneumatic tire of the present invention, the tire oxidation severity or the total deterioration index can be expressed on an objective scale, and the use conditions of the tire can be grasped, so that the tire design can be performed accurately. This can improve the accuracy of tire development and reduce development time.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram illustrating an electrical circuit of a pneumatic tire deterioration evaluation apparatus according to a first embodiment of the present invention. In the first embodiment, evaluation of a deterioration state due to oxidation of tire rubber will be described as an example. In this embodiment, the evaluation target is a pneumatic tire in which a gas having an oxygen concentration of 5% or more is enclosed.

  In the figure, 100 is a pneumatic tire deterioration evaluation device, which comprises a temperature detection unit 101, an air pressure detection unit 102, an air pressure reduction rate calculation unit 103, a severity calculation unit 104, a determination unit 105, and a determination result output unit 106. The computer is mainly composed of a known computer device.

  The temperature detection unit 101 includes a temperature sensor attached to a tire to be evaluated for deterioration, and a digital output circuit that inputs an output signal of the temperature sensor and outputs a digital value of the detected temperature at a predetermined time interval. Yes. The temperature sensor measures any of the tire internal temperature, the tire air temperature, and the tire surface temperature.

  The air pressure detection unit 102 includes an air pressure sensor provided in the air chamber of a tire to be evaluated for deterioration, and a digital output circuit that inputs an output signal of the air pressure sensor and outputs a digital value of the detected air pressure at predetermined time intervals. It is configured.

  The air pressure reduction rate calculation unit 103 converts the air pressure of the measurement result into a temperature converted air pressure that is an air pressure at a predetermined reference temperature (for example, 25 degrees), and calculates the air pressure change rate per unit time from the temperature converted air pressure. The digital value of the calculation result is output. The well-known Boyle's law is used for calculating the temperature-converted air pressure.

  The severity calculation unit 104 inputs the digital value of the temperature-converted air pressure and the digital value of the air pressure decrease rate calculated by the air pressure decrease rate calculation unit 103, calculates the value of oxidation severity (OXY) by a predetermined calculation, The calculation result is output to the determination unit 105.

  The determination unit 105 compares the value of the oxidation severity (OXY) calculated by the severity calculation unit 104 with a predetermined threshold that is set in advance at a predetermined interval, and determines the oxidation severity (OXY). The deterioration level of the tire is determined depending on which threshold value is present, and the determination result is output.

  The determination result output unit 106 inputs the determination result from the determination unit 105 and displays the determination result.

  In this way, the tire's oxidation severity (OXY) can be expressed on an objective scale, so the tire usage conditions can be easily grasped, so that the tire design can be performed accurately and the accuracy of tire development is improved. And development time can be shortened.

  Next, a method for calculating oxidation severity (OXY) performed in the severity calculation unit 104 will be described below with reference to a plurality of examples.

  In the first embodiment, the severity calculating unit 104 determines that the input air pressure change rate value is less than 0 and that the air pressure decrease due to natural leakage is caused, and sequentially adds the air pressure decrease amount P per unit time. Is output to the determination unit 105 as an oxidation severity (OXY) value.

  That is, as shown in FIG. 2, when a tire is used, air in the tire chamber naturally leaks and air pressure decreases. When the tire air pressure decreases, the act of filling the air to increase the tire air pressure to a predetermined value is repeatedly performed. In this embodiment, the amount of air naturally leaking from the tire is sequentially integrated, and this integrated value is used as the value of oxidation severity.

  Further, as shown in FIG. 3, it has been found that the tire durability decreases as the amount obtained by sequentially integrating the amount of air naturally leaked from the tire, that is, the air pressure decrease integrated amount increases. Therefore, the deterioration state of the tire can be grasped by determining the value of oxidation severity (OXY).

  In the second embodiment, the severity calculating unit 104 determines that the input air pressure change rate is less than 0, indicating that the air pressure has decreased due to natural leakage, and converted the air pressure decrease P per unit time into a volume Vp. Then, a value obtained by sequentially integrating the volumes Vp is output to the determination unit 105 as an oxidation severity (OXY) value. When converting the air pressure decrease amount P into the volume Vp, the equation of Boyle's law is used.

  In Example 2, since the air pressure reduction amount varies depending on the initial air pressure and the tire size (air chamber volume), an amount (volume Vp) converted to the volume is used to remove the influence of the initial air pressure and the tire size. .

  In the third embodiment, the severity calculation unit 104 determines that the input air pressure change rate is less than 0, indicating that the air pressure has decreased due to natural leakage, and converted the air pressure decrease amount P per unit time into a volume Vp. At the same time, a value obtained by dividing the volume Vp by the tire inner surface area A is defined as an air permeation amount C per unit area, and a value obtained by sequentially integrating the air permeation amount C as a value of oxidation severity (OXY). Output.

  In Example 3, the air pressure decrease amount varies depending on the initial air pressure and the tire size (air chamber volume), and the air permeation amount per unit area of the tire inner surface is taken into account in consideration of the difference in the tire size (air chamber volume). As a result, the accuracy of oxidation severity is improved.

  In the fourth embodiment, the severity calculation unit 104 determines that the input air pressure change rate value is less than 0 and the air pressure decrease due to natural leakage, and sequentially accumulates the air pressure decrease amount P per unit time. A value obtained by multiplying the oxygen concentration by the oxygen severity is output to the determination unit 105 as an oxidation severity (OXY) value.

  In this example, when the oxygen concentration of the sealed gas of the tire to be evaluated is different, in order to obtain a pure oxygen permeation amount, by multiplying the oxygen concentration, the original oxidation severity is obtained. Value.

  In the fifth embodiment, the severity calculation unit 104 determines that the input air pressure change rate is less than 0, indicating that the air pressure has decreased due to natural leakage, and converted the air pressure decrease amount P per unit time into a volume Vp. Then, a value obtained by multiplying the value obtained by sequentially integrating the volumes Vp by the oxygen concentration is output to the determination unit 105 as an oxidation severity value.

  In Example 5, the amount of decrease in air pressure is the amount (volume Vp) converted to the volume in order to remove the influence of the initial air pressure and the tire size (air chamber volume), and the amount of the sealed gas of the tire to be evaluated As for the oxygen concentration, when the oxygen concentration is different, in order to obtain a purely permeated amount of oxygen, the oxygen concentration is multiplied to obtain the original value of oxidation severity.

  In the sixth embodiment, the severity calculation unit 104 determines that the input air pressure change rate is less than 0, indicating that the air pressure has decreased due to natural leakage, and converted the air pressure decrease P per unit time into a volume Vp. In addition, a value obtained by dividing the volume Vp by the tire inner surface area A is an air permeation amount C per unit area, and a value obtained by multiplying the air permeation amount C sequentially by the oxygen concentration is an oxidation severity ( OXY) value is output to the determination unit 105.

  In Example 6, the air pressure reduction amount varies depending on the initial air pressure and the tire size (air chamber volume), and the air permeation amount per unit area of the tire inner surface is taken into account in consideration of the difference in the tire size (air chamber volume). As for the oxygen concentration of the sealed gas of the tire to be evaluated, when the oxygen concentration is different, in order to obtain a pure oxygen permeation amount, by multiplying the oxygen concentration, the original oxidation severity of The accuracy of oxidation severity is increased.

  Next, a second embodiment of the present invention will be described.

  FIG. 4 is a block diagram showing an electric circuit of the pneumatic tire deterioration evaluation apparatus in the second embodiment of the present invention. In the second embodiment, as in the first embodiment, evaluation of the deterioration state due to oxidation of tire rubber will be described as an example. In this embodiment, the evaluation target is a pneumatic tire in which a gas having an oxygen concentration of 5% or more is enclosed.

  Also, the difference between the second embodiment and the first embodiment described above is that a temperature integrated value calculation unit 201 is added, and a total deterioration index calculation unit 202 instead of a severity calculation unit 104 and a determination unit 105, a determination That is, the unit 203 is provided.

  In the figure, reference numeral 200 denotes a pneumatic tire deterioration evaluation device, a temperature detection unit 101, an air pressure detection unit 102, an air pressure decrease rate calculation unit 103, a temperature integrated value calculation unit 201, a total deterioration index calculation unit 202, a determination unit 203, It consists of a determination result output unit 106, and is composed mainly of a known computer device.

  The temperature detection unit 101 includes a temperature sensor attached to a tire to be evaluated for deterioration, and a digital output circuit that inputs an output signal of the temperature sensor and outputs a digital value of the detected temperature at a predetermined time interval. Yes. The temperature sensor measures any of the tire internal temperature, the tire air temperature, and the tire surface temperature.

  The air pressure detection unit 102 includes an air pressure sensor provided in the air chamber of a tire to be evaluated for deterioration, and a digital output circuit that inputs an output signal of the air pressure sensor and outputs a digital value of the detected air pressure at predetermined time intervals. It is configured.

  The air pressure reduction rate calculation unit 103 converts the air pressure of the measurement result into a temperature converted air pressure that is an air pressure at a predetermined reference temperature (for example, 25 degrees), and calculates the air pressure change rate per unit time from the temperature converted air pressure. The digital value of the calculation result is output. The well-known Boyle's law is used for calculating the temperature-converted air pressure.

  The temperature integrated value calculation unit 201 inputs the detection result from the temperature detection unit 101, and outputs a value obtained by sequentially integrating the temperature values of the detection result to the severity calculation unit 202 as a temperature severity (TTSN) value. . For example, suppose that the detected temperature is T, the predetermined coefficient is α, and TTSN = Σexp (T × α).

  The total deterioration index calculation unit 202 inputs the digital value of the temperature-converted air pressure and the digital value of the air pressure decrease rate calculated by the air pressure decrease rate calculation unit 103, and calculates the value of oxidation severity (OXY) by a predetermined calculation. . Further, the temperature severity (TTSN) value is input from the temperature integrated value calculation unit 201, and the total deterioration index A is calculated from the oxidation severity (OXY) value and the temperature severity (TTSN) value. Is output to the determination unit 105.

  The determination unit 203 compares the value of the total deterioration index A calculated by the total deterioration index calculation unit 202 with a predetermined threshold set in advance at a predetermined interval, and determines which value of the total deterioration index A is The deterioration level of the tire is determined depending on whether it exists between the threshold values, and the determination result is output.

  The determination result output unit 106 receives the determination result from the determination unit 203 and displays the determination result.

  In this way, since the total deterioration index A of the tire can be expressed on an objective scale, the use conditions of the tire can be easily grasped, so that the tire design can be performed accurately, and the accuracy of tire development is improved. Development time can be shortened.

  Next, a method for calculating the total deterioration index A performed in the total deterioration index calculation unit 202 will be described below with reference to a plurality of examples.

  In the seventh embodiment, the total deterioration index calculation unit 202 determines that the air pressure has decreased due to natural leakage when the input air pressure change rate is less than 0, and sequentially integrated the air pressure decrease amount P per unit time. The value is calculated as the value of oxidation severity (OXY). Further, using this oxidation severity (OXY) value and the temperature severity (TTSN) value input from the temperature integrated value calculation unit 201, the total deterioration index A is calculated by the following equation (1) and determined. The data is output to the unit 203.

A = β × {(OXY) ² + (TTSN) ² } ^1/2 (1)
Here, β is a predetermined coefficient. In this equation, the value obtained by squaring the value of the temperature severity (TTSN) is added to the value obtained by squaring the value of the oxidation severity (OXY). A square root is obtained, and a value obtained by multiplying the square root value by a coefficient β is defined as a total deterioration coefficient A.

  That is, as shown in FIG. 5, the tire's 100% modulus and elongation at break depend on the oxidation of the tire rubber and the heat applied to the tire rubber, which causes the tire to deteriorate. In the present embodiment, as shown in FIG. 7, the total deterioration index A is calculated on the assumption that the oxidation severity (OXY) depends on the air pressure decrease integrated amount and the temperature severity (TTSN) depends on the total heat history amount. . Further, in this embodiment, in integrating the oxidation severity (OXY) and the temperature severity (TTSN), both components are orthogonal components, and the total deterioration index is obtained by combining both components using the Pythagorean theorem. Seeking A.

  In the eighth embodiment, the total deterioration index calculation unit 202 determines that the air pressure is decreased due to natural leakage when the value of the input air pressure change rate is less than 0, and sets the air pressure decrease amount P per unit time to the volume Vp. A value obtained by conversion and sequentially integrating the volume Vp is calculated as a value of oxidation severity (OXY). Further, by using the value of the oxidation severity (OXY) and the value of the temperature severity (TTSN) input from the temperature integrated value calculation unit 201, the total deterioration index A is calculated by the above equation (1), and the determination unit Output to 203. When converting the air pressure decrease amount P into the volume Vp, the equation of Boyle's law is used.

  In Example 8, the amount of decrease in air pressure varies depending on the initial air pressure and the tire size (air chamber volume). Therefore, in order to remove the influence of the initial air pressure and the tire size, the amount converted into the volume (volume Vp) is used. .

  In the ninth embodiment, the total deterioration index calculation unit 202 determines that the air pressure is decreased due to natural leakage when the input air pressure change rate is less than 0, and sets the air pressure decrease amount P per unit time to the volume Vp. A value obtained by dividing the volume Vp by the tire inner surface area A is defined as an air permeation amount C per unit area, and a value obtained by sequentially integrating the air permeation amount C is calculated as an oxidation severity (OXY) value. Further, by using the value of the oxidation severity (OXY) and the value of the temperature severity (TTSN) input from the temperature integrated value calculation unit 201, the total deterioration index A is calculated by the above equation (1), and the determination unit Output to 203.

  In Example 9, the air pressure decrease amount varies depending on the initial air pressure and the tire size (air chamber volume), and the air permeation amount per unit area of the tire inner surface is taken into account in consideration of the difference in the tire size (air chamber volume). As a result, the accuracy of oxidation severity is improved.

  In the tenth embodiment, the total deterioration index calculation unit 202 determines that the input air pressure change rate value is less than 0, the air pressure decrease due to natural leakage, and sequentially accumulates the air pressure decrease amount P per unit time. A value obtained by multiplying the value by the oxygen concentration is calculated as the value of oxidation severity (OXY). Further, by using the value of the oxidation severity (OXY) and the value of the temperature severity (TTSN) input from the temperature integrated value calculation unit 201, the total deterioration index A is calculated by the above equation (1), and the determination unit Output to 203.

  In this example, when the oxygen concentration of the sealed gas of the tire to be evaluated is different, in order to obtain a pure oxygen permeation amount, by multiplying the oxygen concentration, the original oxidation severity is obtained. Value.

  In the eleventh embodiment, the total deterioration index calculation unit 202 determines that the air pressure has decreased due to natural leakage when the value of the input air pressure change rate is less than 0, and sets the air pressure decrease amount P per unit time to the volume Vp. A value obtained by converting and sequentially multiplying the volume Vp by the oxygen concentration is calculated as the value of the oxidation severity. Further, by using the value of the oxidation severity (OXY) and the value of the temperature severity (TTSN) input from the temperature integrated value calculation unit 201, the total deterioration index A is calculated by the above equation (1), and the determination unit Output to 203.

  In Example 11, the amount of decrease in air pressure is the amount converted into volume (volume Vp) in order to remove the influence of initial air pressure and tire size (air chamber volume), and the amount of air contained in the tire to be evaluated As for the oxygen concentration, when the oxygen concentration is different, in order to obtain a purely permeated amount of oxygen, the oxygen concentration is multiplied to obtain the original value of oxidation severity.

  In the twelfth embodiment, the total deterioration index calculation unit 202 determines that the air pressure decrease due to natural leakage occurs when the input air pressure change rate value is less than 0, and sets the air pressure decrease amount P per unit time to the volume Vp. A value obtained by dividing the volume Vp by the tire inner surface area A is defined as an air permeation amount C per unit area, and a value obtained by multiplying the air permeation amount C sequentially by the oxygen concentration is an oxidation severity. Calculated as the value of (OXY). Further, by using the value of the oxidation severity (OXY) and the value of the temperature severity (TTSN) input from the temperature integrated value calculation unit 201, the total deterioration index A is calculated by the above equation (1), and the determination unit Output to 203.

  In Example 12, the air pressure decrease amount varies depending on the initial air pressure and the tire size (air chamber volume), and the air permeation amount per unit area of the tire inner surface is taken into account in consideration of the difference in the tire size (air chamber volume). As for the oxygen concentration of the sealed gas of the tire to be evaluated, when the oxygen concentration is different, in order to obtain a pure oxygen permeation amount, by multiplying the oxygen concentration, the original oxidation severity of The accuracy of oxidation severity is increased.

  In the thirteenth embodiment, the total deterioration index calculation unit 202 determines that the input air pressure change rate value is less than 0, and that the air pressure decrease amount P per unit time is sequentially integrated by determining that the air pressure decrease is due to natural leakage. The value is calculated as the value of oxidation severity (OXY). Further, using this oxidation severity (OXY) value and the temperature severity (TTSN) value input from the temperature integrated value calculation unit 201, the total deterioration index A is calculated by the following equation (2) and determined. To the unit 203.

A = θ × (OXY × TTSN) (2)
Here, θ is a predetermined coefficient. In this equation, the value obtained by multiplying the value of the oxidation severity (OXY) by the value of the temperature severity (TTSN) is divided by 2, and the value obtained by multiplying this value by the coefficient θ Is the total deterioration coefficient A.

  That is, in this embodiment, as shown in FIG. 7, the total deterioration index A is calculated on the assumption that the oxidation severity (OXY) depends on the air pressure decrease integrated amount and the temperature severity (TTSN) depends on the total heat history amount. ing. Further, in this embodiment, in integrating the oxidation severity (OXY) and the temperature severity (TTSN), both components are orthogonal components, and the total deterioration index A is defined as an area of a triangle formed by these orthogonal components. Seeking.

  In the fourteenth embodiment, the total deterioration index calculation unit 202 determines that the air pressure decrease due to natural leakage occurs when the input air pressure change rate value is less than 0, and sets the air pressure decrease amount P per unit time to the volume Vp. A value obtained by conversion and sequentially integrating the volume Vp is calculated as a value of oxidation severity (OXY). Further, by using the value of the oxidation severity (OXY) and the value of the temperature severity (TTSN) input from the temperature integrated value calculation unit 201, the total deterioration index A is calculated by the above equation (2), and the determination unit Output to 203. When converting the air pressure decrease amount P into the volume Vp, the equation of Boyle's law is used.

  In Example 14, since the air pressure reduction amount varies depending on the initial air pressure and the tire size (air chamber volume), the amount converted into the volume (volume Vp) is used to remove the influence of the initial air pressure and the tire size. .

  In the fifteenth embodiment, the total deterioration index calculation unit 202 determines that the air pressure is decreased due to natural leakage when the value of the input air pressure change rate is less than 0, and sets the air pressure decrease amount P per unit time to the volume Vp. A value obtained by dividing the volume Vp by the tire inner surface area A is defined as an air permeation amount C per unit area, and a value obtained by sequentially integrating the air permeation amount C is calculated as an oxidation severity (OXY) value. Further, by using the value of the oxidation severity (OXY) and the value of the temperature severity (TTSN) input from the temperature integrated value calculation unit 201, the total deterioration index A is calculated by the above equation (2), and the determination unit Output to 203.

  In Example 15, the air pressure reduction amount varies depending on the initial air pressure and the tire size (air chamber volume), and in order to take into account the difference in tire size (air chamber volume), the air permeation amount per unit area of the tire inner surface As a result, the accuracy of oxidation severity is improved.

  In the sixteenth embodiment, the total deterioration index calculation unit 202 determines that the input air pressure change rate value is less than 0, indicating that the air pressure has decreased due to natural leakage, and sequentially integrated the air pressure decrease amount P per unit time. A value obtained by multiplying the value by the oxygen concentration is calculated as the value of oxidation severity (OXY). Further, by using the value of the oxidation severity (OXY) and the value of the temperature severity (TTSN) input from the temperature integrated value calculation unit 201, the total deterioration index A is calculated by the above equation (2), and the determination unit Output to 203.

  In this example, when the oxygen concentration of the sealed gas of the tire to be evaluated is different, in order to obtain a pure oxygen permeation amount, by multiplying the oxygen concentration, the original oxidation severity is obtained. Value.

  In the seventeenth embodiment, the total deterioration index calculation unit 202 determines that the air pressure is decreased due to natural leakage when the value of the input air pressure change rate is less than 0, and sets the air pressure decrease amount P per unit time to the volume Vp. A value obtained by converting and sequentially multiplying the volume Vp by the oxygen concentration is calculated as the value of the oxidation severity. Further, by using the value of the oxidation severity (OXY) and the value of the temperature severity (TTSN) input from the temperature integrated value calculation unit 201, the total deterioration index A is calculated by the above equation (2), and the determination unit Output to 203.

  In Example 17, the amount of decrease in air pressure is the amount (volume Vp) converted to volume in order to remove the influence of initial air pressure and tire size (volume in the air chamber), and the amount of air contained in the tire to be evaluated As for the oxygen concentration, when the oxygen concentration is different, in order to obtain a purely permeated amount of oxygen, the oxygen concentration is multiplied to obtain the original value of oxidation severity.

  In the eighteenth embodiment, the total deterioration index calculation unit 202 determines that the air pressure is decreased due to natural leakage when the input air pressure change rate is less than 0, and sets the air pressure decrease amount P per unit time to the volume Vp. A value obtained by dividing the volume Vp by the tire inner surface area A is defined as an air permeation amount C per unit area, and a value obtained by multiplying the air permeation amount C sequentially by the oxygen concentration is an oxidation severity. Calculated as the value of (OXY). Further, by using the value of the oxidation severity (OXY) and the value of the temperature severity (TTSN) input from the temperature integrated value calculation unit 201, the total deterioration index A is calculated by the above equation (2), and the determination unit Output to 203.

  In Example 18, the air pressure reduction amount varies depending on the initial air pressure and the tire size (air chamber volume), and the air permeation amount per unit area of the tire inner surface is taken into account in consideration of the difference in tire size (air chamber volume). As for the oxygen concentration of the sealed gas of the tire to be evaluated, when the oxygen concentration is different, in order to obtain a pure oxygen permeation amount, by multiplying the oxygen concentration, the original oxidation severity of The accuracy of oxidation severity is increased.

The block diagram which shows the electric system circuit of the deterioration evaluation apparatus of the pneumatic tire in 1st Embodiment of this invention. Diagram explaining repeated natural leakage and air filling in tires Diagram for explaining the relationship between the total amount of tire pressure drop and tension durability The block diagram which shows the electric system circuit of the deterioration evaluation apparatus of the pneumatic tire in 2nd Embodiment of this invention. Diagram explaining deterioration of physical properties of tire The figure explaining the calculation method of the total degradation parameter | index in 2nd Embodiment of this invention. The figure explaining the calculation method of the total degradation parameter | index in 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Degradation evaluation apparatus of a pneumatic tire, 101 ... Temperature detection part, 102 ... Air pressure detection part, 103 ... Air pressure reduction rate calculation part, 104 ... Severity calculation part, 105 ... Judgment part, 106 ... Judgment result output part, 201 ... temperature integrated value calculation unit, 202 ... total deterioration index calculation unit, 203 ... determination unit.

Claims (11)

Information relating to the air pressure and temperature of a pneumatic tire detected sequentially by the air pressure sensor and the temperature sensor every predetermined time is input to the device, and the device encloses a gas having an oxygen concentration of 5% or more based on the information. It is a method for evaluating deterioration of a pneumatic tire for evaluating deterioration of the entering tire,
The device is
Based on the information, the air pressure of the measurement result is converted into a temperature converted air pressure that is an air pressure at a predetermined reference temperature,
Calculate the air pressure change rate per unit time from the temperature converted air pressure,
When the value of the air pressure change rate is less than 0, the air pressure decrease amount P per unit time is sequentially integrated,
The integrated value of the air pressure reduction amount P is regarded as oxidation severity,
A method for evaluating deterioration of a pneumatic tire, wherein the deterioration of the tire is evaluated using the oxidation severity. Information relating to the air pressure and temperature of a pneumatic tire detected sequentially by the air pressure sensor and the temperature sensor every predetermined time is input to the device, and the device encloses a gas having an oxygen concentration of 5% or more based on the information. It is a method for evaluating deterioration of a pneumatic tire for evaluating deterioration of the entering tire,
The device is
Based on the information, the air pressure of the measurement result is converted into a temperature converted air pressure that is an air pressure at a predetermined reference temperature,
Calculate the air pressure change rate per unit time from the temperature converted air pressure,
When the value of the air pressure change rate is less than 0, the air pressure decrease amount P per unit time is converted into a volume Vp,
The volume Vp is sequentially integrated,
The integrated value of the volume Vp is regarded as oxidation severity,
A method for evaluating deterioration of a pneumatic tire, wherein the deterioration of the tire is evaluated using the oxidation severity. Information relating to the air pressure and temperature of a pneumatic tire detected sequentially by the air pressure sensor and the temperature sensor every predetermined time is input to the device, and the device encloses a gas having an oxygen concentration of 5% or more based on the information. It is a method for evaluating deterioration of a pneumatic tire for evaluating deterioration of the entering tire,
The device is
Based on the information, the air pressure of the measurement result is converted into a temperature converted air pressure that is an air pressure at a predetermined reference temperature,
Calculate the air pressure change rate per unit time from the temperature converted air pressure,
When the value of the air pressure change rate is less than 0, the air pressure decrease amount P per unit time is converted into the volume Vp, and the value obtained by dividing the volume Vp by the tire inner surface area A is the air permeation amount C per unit area. And sequentially integrating the air permeation amount C,
The integrated value of the air permeation amount C is regarded as oxidation severity,
A method for evaluating deterioration of a pneumatic tire, wherein the deterioration of the tire is evaluated using the oxidation severity. Information relating to the air pressure and temperature of a pneumatic tire detected sequentially by the air pressure sensor and the temperature sensor every predetermined time is input to the device, and the device encloses a gas having an oxygen concentration of 5% or more based on the information. It is a method for evaluating deterioration of a pneumatic tire for evaluating deterioration of the entering tire,
The device is
Based on the information, the air pressure of the measurement result is converted into a temperature converted air pressure that is an air pressure at a predetermined reference temperature,
Calculate the air pressure change rate per unit time from the temperature converted air pressure,
When the value of the air pressure change rate is less than 0, the air pressure decrease amount P per unit time is sequentially integrated,
A value obtained by multiplying the integrated value of the air pressure decrease amount P by the oxygen concentration is referred to as oxidation severity,
A method for evaluating deterioration of a pneumatic tire, wherein the deterioration of the tire is evaluated using the oxidation severity. Information relating to the air pressure and temperature of a pneumatic tire detected sequentially by the air pressure sensor and the temperature sensor every predetermined time is input to the device, and the device encloses a gas having an oxygen concentration of 5% or more based on the information. It is a method for evaluating deterioration of a pneumatic tire for evaluating deterioration of the entering tire,
The device is
Based on the information, the air pressure of the measurement result is converted into a temperature converted air pressure that is an air pressure at a predetermined reference temperature,
Calculate the air pressure change rate per unit time from the temperature converted air pressure,
When the value of the air pressure change rate is less than 0, the air pressure decrease amount P per unit time is converted into a volume Vp,
The volume Vp is sequentially integrated,
The value obtained by multiplying the integrated value of the volume Vp by the oxygen concentration is referred to as oxidation severity,
A method for evaluating deterioration of a pneumatic tire, wherein the deterioration of the tire is evaluated using the oxidation severity. Information relating to the air pressure and temperature of a pneumatic tire detected sequentially by the air pressure sensor and the temperature sensor every predetermined time is input to the apparatus, and the apparatus encloses a gas having an oxygen concentration of 5% or more based on the information. It is a method for evaluating deterioration of a pneumatic tire for evaluating deterioration of the entering tire,
The device is
Based on the information, the air pressure of the measurement result is converted into a temperature converted air pressure that is an air pressure at a predetermined reference temperature,
Calculate the air pressure change rate per unit time from the temperature converted air pressure,
When the value of the air pressure change rate is less than 0, the air pressure decrease amount P per unit time is converted into a volume Vp, and a value obtained by dividing the volume Vp by the tire inner surface area A is an air permeation amount C per unit area. And sequentially integrating the air permeation amount C,
A value obtained by multiplying the integrated value of the air permeation amount C by the oxygen concentration is referred to as oxidation severity,
A method for evaluating deterioration of a pneumatic tire, wherein the deterioration of the tire is evaluated using the oxidation severity. Information relating to the air pressure and temperature of a pneumatic tire detected sequentially by the air pressure sensor and the temperature sensor every predetermined time is input to the device, and the device encloses a gas having an oxygen concentration of 5% or more based on the information. It is a method for evaluating deterioration of a pneumatic tire for evaluating deterioration of the entering tire,
The device is
Based on the information, the air pressure of the measurement result is converted into a temperature converted air pressure that is an air pressure at a predetermined reference temperature,
Calculate the air pressure change rate per unit time from the temperature converted air pressure,
When the value of the air pressure change rate is less than 0, a value obtained by sequentially integrating the air pressure decrease amount P per unit time is regarded as oxidation severity,
Based on the information, the value obtained by sequentially integrating the temperature of the measurement result is a temperature severity,
Obtain a total degradation index from the oxidation severity and temperature severity,
A method for evaluating deterioration of a pneumatic tire, wherein the deterioration of the tire is evaluated using the total deterioration index. The detected temperature is T, the predetermined coefficient is α, and the temperature severity (TTSN) is obtained by the following equation: TTSN = Σexp (T × α)
The method for evaluating deterioration of a pneumatic tire according to claim 7. From the oxidation severity (OXY) and the temperature severity (TTSN), a predetermined coefficient is set as β, and the total deterioration index A is obtained using the following equation: A = β × {(OXY) ² + (TTSN) ² } ^1/2
The method for evaluating deterioration of a pneumatic tire according to claim 7 or claim 8, wherein: From the oxidation severity (OXY) and the temperature severity (TTSN), a predetermined coefficient is set as θ, and the total deterioration index A is obtained using the following equation: A = θ × (OXY × TTSN)
The method for evaluating deterioration of a pneumatic tire according to claim 7 or claim 8, wherein: 11. The temperature severity (TTSN) is obtained using the detected temperature by detecting either the temperature inside the tire chamber or the tire tread surface temperature by the temperature sensor. 11. Deterioration evaluation method of pneumatic tire as described in 2.

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