JP2006170783A - Method, apparatus and program for tire endurance test - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method, an apparatus and a program for a tire endurance test, which can surely detect a tire failure at its early stage. <P>SOLUTION: The method comprises; continuously varying an arbitrary element among a plurality of elements which make up an endurance test condition, and establishing each endurance test condition (step ST101, step ST104); determining a predicted failure temperature index ΔTc based on a failure temperature index ΔT obtained by a former tire endurance test (step ST102); acquiring a surface temperature distribution of a tire in each endurance test condition by continuously varying the arbitrary element (step ST103, step ST105); calculating a difference of surface temperature distribution from respective endurance test conditions (step ST106); calculating the failure temperature index ΔT based on the average value Tave and the maximum value Tmax (step ST107); determining whether the failure temperature index ΔT exceeds the predicted failure temperature index ΔTc (step ST108); and detecting a failure (step ST109). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a tire endurance test method, a tire endurance test apparatus, and a tire endurance test program. More specifically, the present invention relates to a tire endurance test method, a tire endurance test apparatus, and a tire endurance test for detecting a failure in a tire endurance test. It is about the program.

  A pneumatic tire (hereinafter simply referred to as a “tire”) is a vehicle such as a passenger car that moves on the road surface so that the vehicle comes into contact with the road surface and power from a power source such as an engine mounted on the vehicle. Is the only one that transmits to the target surface. Therefore, the durability performance until the failure of the tire, which is the performance of the tire, greatly affects the travel limit of the vehicle. Tire failures are considered to be mainly due to temperature failures and failure due to mechanical problems.

  These tire failures change the temperature and shape of the failure location when the tire actually fails. Thus, in the conventional tire durability test, as shown in Patent Document 1, a technique for detecting a tire failure based on the temperature of the surface of the tire has been proposed. The conventional tire failure detection method and apparatus shown in Patent Document 1 repeats the process of measuring the surface temperature of a rotating tire by a non-contact temperature sensor. Then, the front and back surface temperature data measured at a predetermined time interval are compared at corresponding positions on the circumference of the tire to calculate the temperature change amount, and the temperature change amount is equal to or greater than a predetermined threshold value. In this case, it is determined that a failure has occurred. Thereby, a failure can be detected without being influenced by the expansion of the tire.

JP 2004-239724 A

  However, in the tire durability test method and apparatus shown in Patent Document 1 described above, a tire failure is based on a temperature change amount comparing front and rear surface temperatures measured at a predetermined time interval at each corresponding position on the tire circumference. Is detected. Here, in a tire durability test, for example, when the rotational speed of the tire continuously increases, the surface temperature of the entire tire increases as the rotational speed increases. The rise in the surface temperature of the entire tire differs depending on the position (tire center, tire shoulder, etc.), and the amount of temperature change comparing the front and back surface temperatures measured at a predetermined time interval also varies depending on the position. That is, when a tire failure is detected based on a temperature change amount at a certain position, it is necessary to determine whether the temperature change amount is caused by an increase in tire rotation speed or a failure. Therefore, in the tire durability test method and apparatus disclosed in Patent Document 1, when the surface temperature of the entire tire changes by continuously changing any element of the durability test conditions in the tire durability test, the threshold value There is a problem that the setting of is very difficult.

  Further, in the tire durability test method and apparatus shown in Patent Document 1, a tire failure is detected based on a temperature change amount resulting from continuously changing any element of the durability test conditions in the tire durability test. In order to avoid this, it is necessary to increase the threshold value. If the threshold value is increased, that is, the temperature change amount is increased, a failure has already occurred inside the tire, and the failure of the tire cannot be detected until the surface temperature at the failure position is significantly increased. That is, the tire failure can be detected at the final stage of the failure where the surface temperature becomes high, but there is a problem that the failure at the initial stage where the surface temperature starts to increase due to the failure cannot be detected.

  Therefore, the present invention has been made in view of the above, and provides a tire durability test method, a tire durability test apparatus, and a tire durability test program capable of reliably detecting a tire failure at an early stage. Objective.

  In order to solve the above-described problems and achieve the object, the present invention provides a tire durability test method in which an arbitrary element is continuously changed from a durability test condition consisting of a plurality of elements, and Surface temperature distribution acquisition procedure for acquiring surface temperature distribution, surface temperature distribution under any endurance test condition among the respective endurance test conditions, and surface temperature distribution under a pre-endurance test condition prior to the endurance test condition A failure temperature index for calculating a failure temperature index ΔT based on a surface temperature distribution difference calculation procedure for calculating a temperature distribution difference, a distribution value Ts based on the calculated surface temperature distribution difference, and a maximum value Tmax of the surface temperature distribution difference The predicted failure temperature based on the calculation procedure and the failure temperature index ΔT calculated in the previous tire endurance test or the most recently calculated failure temperature index ΔT A failure prediction temperature index determination procedure for determining the number ΔTc; a failure temperature determination procedure for determining whether the failure temperature index ΔT exceeds the failure prediction temperature index ΔTc; and the failure temperature index ΔT determines the failure prediction temperature index ΔTc. And a failure detection procedure for detecting a failure when exceeding.

  According to the present invention, in the tire durability test method, the failure prediction temperature index determination procedure includes a failure temperature index ΔTe when a failure is detected among the failure temperature indices ΔT calculated in the previous tire durability test, and The failure prediction temperature index ΔTc is determined based on the failure temperature index ΔTb before detecting the failure.

  According to the present invention, in the tire durability test method, the failure prediction temperature index determining procedure determines the failure prediction temperature index ΔTc within a range of 1.5 to 5.0.

  According to the present invention, in the tire endurance test method, the failure prediction temperature index determination procedure sets the failure prediction temperature index ΔTc to 1.5 to 2.0 times the most recently calculated failure temperature index ΔT. It is characterized by determining.

According to the present invention, in the tire durability test method, the distribution value Ts based on the calculated surface temperature distribution difference is an average value Tave of the calculated surface temperature distribution difference, and the failure temperature index calculation procedure is as follows: The failure temperature index ΔT is calculated by the following equation.
ΔT = Tmax / Tave (1)

  Further, in the present invention, in the tire durability test method, the surface temperature distribution acquisition procedure acquires a tire surface temperature distribution under at least each of the durability test conditions in either the tire width direction or the tire circumferential direction. And

  Further, in the tire durability test apparatus, surface temperature measurement means for continuously changing any element from the durability test conditions consisting of a plurality of elements and measuring the surface temperature distribution of the tire under each durability test condition; A surface temperature distribution difference calculating means for calculating a surface temperature distribution difference between a surface temperature distribution in an arbitrary endurance test condition and a surface temperature distribution in a previous endurance test condition before the arbitrary endurance test condition among the respective endurance test conditions; A failure temperature index calculating means for calculating a failure temperature index ΔT based on the distribution value Ts based on the calculated surface temperature distribution difference and a maximum value Tmax of the surface temperature distribution difference, and calculated in a previous tire durability test. Failure predictive temperature index determining unit for determining the predicted failure temperature index ΔTc based on the failure temperature index ΔT or the most recently calculated failure temperature index ΔT Failure temperature determination means for determining whether the failure temperature index ΔT exceeds the failure prediction temperature index ΔTc; failure detection means for detecting a failure when the failure temperature index ΔT exceeds the failure prediction temperature index ΔTc; It is characterized by providing.

  According to these inventions, the surface temperature distribution difference between the surface temperature distribution in an arbitrary endurance test condition and the surface temperature distribution in a previous endurance test condition before the arbitrary endurance test condition among the above endurance test conditions, that is, a tire A tire failure is detected by comparing the overall surface temperature distribution difference of the tire with the maximum value Tmax of the surface temperature distribution difference of the tire. In other words, even when the surface temperature of the entire tire varies depending on the position by continuously changing any element of the durability test conditions in the tire durability test, the maximum value for the entire difference in tire surface temperature distribution Since the tire failure is detected based on the change in Tmax, the tire failure can be reliably detected at the initial stage.

  Further, according to the present invention, in the tire durability test method, a profile distribution acquisition procedure for acquiring a tire profile distribution under each of the durability test conditions, a profile distribution under any of the durability test conditions, and the arbitrary A profile distribution difference calculation procedure for calculating a profile distribution difference from a profile distribution in a previous durability test condition prior to the durability test condition, a distribution value Ds based on the calculated profile distribution difference, and a maximum value Dmax of the profile distribution difference Based on the failure displacement index calculation procedure for calculating the failure displacement index ΔD based on the above, and the failure displacement index ΔDc calculated based on the failure displacement index ΔD calculated in the previous tire endurance test or the most recently calculated failure displacement index ΔD Failure predictive displacement index determination procedure to be determined and the failure displacement A failure displacement determination procedure for determining whether a number ΔD exceeds the failure prediction displacement index ΔDc, wherein the failure detection procedure includes at least the failure temperature index ΔT exceeding the failure prediction temperature index ΔTc or the failure A failure is detected in any one of cases where the displacement index ΔD exceeds the predicted failure index ΔDc.

  According to the present invention, not only the tire failure is detected by comparing the entire tire surface temperature distribution difference with the tire surface temperature distribution difference maximum value Tmax, but also any durability among the durability test conditions. The profile distribution difference between the profile distribution in the test condition and the profile distribution in the pre-endurance test condition before the arbitrary endurance test condition, that is, the entire tire profile distribution difference is compared with the maximum value Dmax of the tire profile distribution difference. To detect a tire failure. In other words, by continuously changing any element of the endurance test conditions in the tire endurance test, even if the surface temperature or profile of the entire tire changes differently depending on the position, Since a tire failure is detected by a change in the maximum value Tmax or a change in the maximum value Dmax with respect to the entire tire profile distribution difference, a tire failure can be detected more reliably at an initial stage.

  Further, the present invention is characterized by causing a computer to execute the tire durability test method. According to the present invention, by causing the computer to read and execute the program, the tire durability test method can be realized using the computer, and the same effects as those of these methods can be obtained.

  Further, in the present invention, in the tire durability test method, a profile distribution acquisition procedure for continuously changing an arbitrary element from a durability test condition including a plurality of elements and acquiring a tire profile distribution in each durability test condition; A profile distribution difference calculation procedure for calculating a profile distribution difference between a profile distribution under an arbitrary endurance test condition and a profile distribution under a previous endurance test condition before the arbitrary endurance test condition among the endurance test conditions, and the calculated A failure displacement index calculation procedure for calculating a failure displacement index ΔD based on the distribution value Ds based on the profile distribution difference and the maximum value Dmax of the profile distribution difference, the failure displacement index ΔD calculated in the previous tire endurance test or the latest Failure prediction displacement index based on the failure displacement index ΔD calculated in Failure prediction displacement index determination procedure for determining Dc, failure displacement determination procedure for determining whether the failure displacement index ΔD exceeds the failure prediction displacement index ΔDc, and the failure displacement index ΔD exceeds the failure prediction displacement index ΔDc And a failure detection procedure for detecting a failure.

  According to the present invention, the profile distribution difference between the profile distribution in an arbitrary endurance test condition among the endurance test conditions and the profile distribution in the previous endurance test condition before the arbitrary endurance test condition, that is, the tire profile distribution difference And the maximum value Dmax of the profile distribution difference of the tire are compared to detect a tire failure. In other words, by continuously changing any element of the durability test conditions in the tire durability test, even when the profile of the entire tire varies depending on the position, the maximum value Dmax with respect to the entire tire profile distribution difference Since the tire failure is detected by the change, the tire failure can be reliably detected at the initial stage.

  According to the tire durability test method, the tire durability test apparatus, and the tire durability test program according to the present invention, it is possible to reliably detect a tire failure at an initial stage.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited to the best mode for carrying out the invention. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same. In the following embodiments, a case where a drum type tire durability test apparatus is used will be described. However, a flat panel type or flat belt type tire test apparatus may be used. In addition, even if a tire is mounted on an actual vehicle, the surface temperature or profile of the mounted tire is measured, and the tire durability test method is realized using the measured tire surface temperature distribution or tire profile distribution. good. Further, a tire tire model is created, the tire surface temperature or profile is predicted from the state of the tire model in the durability test condition, and the tire durability test method is performed using the predicted tire surface temperature distribution or tire profile distribution. May be realized.

  FIG. 1 is a diagram illustrating a configuration example of a tire durability test apparatus that executes the tire durability test method according to the first embodiment. FIG. 2 is a diagram illustrating a configuration example of the detection apparatus according to the first embodiment. The tire durability test apparatus 1-1 includes a test drum 2, a tire 3 to be tested, a support device 4 that rotatably supports the tire 3, a temperature sensor 5 that measures the surface temperature of the tire 3, The surface temperature distribution of the tire 3 measured by the temperature sensor 5 is input, and the detection device 6 detects a failure of the tire 3.

  The test drum 2 is in contact with the surface of the tire 3 and rotates the tire 3 supported by the support device 4. That is, the test drum 2 serves as a road surface when the tire 3 is mounted on the vehicle. Further, the rotation speed of the test drum 2 can be freely adjusted by a rotation speed signal output from the detection device 6.

  The tire 3 is assembled to a rim (not shown), and this rim is rotatably supported by the support device 4.

  The support device 4 can move in a direction to approach or leave the test drum 2 as indicated by an arrow A by a load signal output from the detection device 6. That is, the load applied to the tire 3 can be adjusted by the support device 4 moving in the arrow A direction. Further, the support device 4 rotates the tire 3 with respect to the test drum 2 as shown by an arrow B by the slip angle signal output from the detection device 6, so that the tire 3 is rotated with respect to the rotation direction of the test drum 2. The angle can be adjusted, that is, the slip angle of the tire 3 can be adjusted. Further, by rotating the tire 3 with respect to the test drum 2 as indicated by an arrow C by the camber angle signal output from the detection device 6, the angle of the tire 3 with respect to the radial direction of the test drum 2 is adjusted, that is, The camber angle of the tire 3 can be adjusted.

  The temperature sensor 5 is a surface temperature measuring means, and is a non-contact type temperature sensor such as an infrared thermal image measuring device, and can measure the surface temperature of the tire. This temperature sensor 5 is arranged so as to face the tire 3 and continuously measures the surface temperature of the tire 3 rotated by the test drum 2, and a thermal image of the surface of the tire 3, that is, the surface temperature distribution of the tire 3. Are continuously output to the detection device 6 as surface temperature distribution data. The surface temperature distribution data may be color image data, image data obtained by binarizing each pixel, or grayscale image data.

  The detection device 6 includes an input / output port (I / O) 61 for inputting / outputting an input signal such as the surface temperature distribution data and an output signal such as a rotational speed signal, a load signal and a slip angle signal, a processing unit 62, And a storage unit 63. An input / output device 7 is connected to the detection device 6, and an input means 71 provided therein is connected to an input / output port 61, and the size of the tire 3, the air pressure of the tire 3, and the test drum 2. Further, endurance test conditions such as the rotational speed of the tire, the load applied to the tire 3, the slip angle of the tire 3, and other data are given to the detection device 6. Here, input devices such as a keyboard, a mouse, and a microphone can be used as the input means 71.

  The processing unit 62 includes a memory such as a RAM and a ROM, and a CPU (Central Processing Unit). The processing unit 62 includes a surface temperature acquisition unit 64, a surface temperature distribution difference calculation unit 65, a failure temperature index calculation unit 66, a failure prediction temperature index determination unit 67, a failure temperature determination unit 68, and a failure detection unit 69. It is comprised by. In the tire endurance test, the processing unit 62 reads the tire endurance test program into a memory (not shown) of the processing unit 62 based on the continuous surface temperature distribution data input to the detection device as described above. I do. Note that the processing unit 62 appropriately stores a numerical value in the middle of the calculation in the storage unit 63 and appropriately calculates the stored numerical value from the storage unit 63 to perform the calculation. The processing unit 62 may be realized by dedicated hardware instead of the tire durability test program.

  The surface temperature distribution difference created by calculation by the processing unit 62, the failure temperature index ΔT in each durability test condition, and the like are displayed by the display means 72 of the input / output device 7. Here, a CRT (Cathode Ray Tube), a liquid crystal display device, or the like can be used as the display means 72. Further, the created surface temperature distribution difference, failure temperature index ΔT under each durability test condition, and the like can be output to a printer (not shown). The storage unit 63 may be provided in the processing unit 62, or may be provided in another device (for example, a database server). Moreover, the structure which can access the detection apparatus 6 by the wired or wireless method from the terminal device which is not shown in figure provided with the input / output device 7 may be sufficient.

  The storage unit 63 stores a tire durability test program in which the tire durability test method according to the present invention for realizing the tire durability test method according to the present invention is incorporated. Here, the storage unit 63 is a fixed disk device such as a hard disk device, a flexible disk, a magneto-optical disk device, or a non-volatile memory such as a flash memory (a storage medium that can only be read such as a CD-ROM), It can be constituted by storage means such as a volatile memory such as RAM (Random Access Memory), or a combination thereof.

  The tire endurance test program is not necessarily limited to a single configuration, but cooperates with a program already stored in a computer system, for example, a separate program represented by an OS (Operating System). The function may be achieved. Further, a tire durability test program for realizing the function of the processing unit 62 shown in FIG. 1 is stored in a computer-readable recording medium, and the tire durability test program recorded on the recording medium is read into a computer system, The tire durability test method according to the present invention may be executed by executing the method. The “computer system” here includes an OS and hardware such as peripheral devices.

  Next, a tire durability test method will be described. Here, the endurance test condition of the tire endurance test method includes a plurality of elements, and is performed by continuously changing an arbitrary element among the plurality of elements. Here, the plurality of elements include tire size, air pressure, rotational speed, load, slip angle, camber angle, and the like. In the tire durability test method according to Example 1 below, as an example, the rotational speed as an arbitrary element is continuously changed. Specifically, the rotational speed is increased by 30 km / h.

  FIG. 3 is a flowchart of the tire durability test method according to the first embodiment. FIG. 4 is a diagram showing the surface temperature distribution under the initial durability test conditions. FIG. 5 is a diagram showing the surface temperature distribution in the initial and subsequent durability test conditions. FIG. 6 is a diagram showing a difference in surface temperature distribution. FIG. 7 is a diagram showing a surface temperature distribution under each durability test condition. FIG. 8 is a diagram illustrating the relationship between the failure temperature index and the failure prediction temperature index.

  First, as shown in FIG. 3, in the tire durability test method according to the first embodiment, initial durability test conditions are first set (step ST101). Specifically, the input means 71 inputs tire size, air pressure, load, camber angle, and initial rotational speed as initial durability test conditions. Here, for example, the tire size is 225 / 45ZR17, the air pressure is 230 kPa, the load is 4 kN, the camber angle is 2 °, and the initial rotational speed is 120 km / h. The detection device 6 rotates the test drum 2 and moves or rotates the support device 4 based on the input initial durability test conditions. Thereby, the tire 3 is set to the initial durability test conditions.

  Next, the predicted failure temperature index determination unit 67 of the processing unit 62 of the detection device 6 determines the predicted failure temperature index ΔTc (step ST102). Here, the storage unit 63 stores a failure temperature index ΔT, which will be described later, in each durability test condition in the tire durability test before the current tire durability test. The failure prediction temperature index determination unit 67 is the same as or similar to the current tire endurance test condition (mainly the initial tire endurance test condition) among the endurance test conditions stored in the storage unit 63. The failure temperature index ΔT is acquired. Then, the failure prediction temperature index determining unit 67 includes a failure temperature index ΔTe when the failure of the tire 3 is detected in the acquired failure temperature index ΔT, and a failure temperature index ΔTb before detecting the failure of the tire 3. Based on the above, the failure prediction temperature index ΔTc is determined. Note that a failure temperature index ΔT, which will be described later, in each durability test condition in the previous tire durability test may be stored in a database provided separately from the detection device 6 instead of the storage unit 63. In this case, the detection device 6 and the database are connected via the input / output port 61, and the failure prediction temperature index determination unit 67 accesses the database as appropriate.

  Here, this failure prediction temperature index ΔTc is preferably in the range of 1.5 to 5.0 when a failure temperature index ΔT described later is calculated by the following equation (2). If this is less than 1.5, the maximum value Tmax with respect to the entire difference in surface temperature distribution of the tire 3 is small, so the local temperature change is small with respect to the temperature change in the entire width direction of the tire 3 and the tire 3 fails. This is because they have not. In addition, if it exceeds 5.0, the maximum value Tmax with respect to the entire surface temperature distribution difference of the tire 3 is large, so that the local temperature change becomes too large with respect to the temperature change in the entire width direction of the tire 3. This is because a failure cannot be detected at an early stage.

  Next, the surface temperature distribution acquisition unit 64 of the processing unit 62 acquires the surface temperature distribution under the initial durability test conditions (step ST103). The surface temperature distribution of the tire 3 is measured by the temperature sensor 5 with the tire 3 set to the initial durability test conditions. The surface temperature distribution acquisition unit 64 acquires the surface temperature distribution data measured and output to the detection device 6 to obtain the surface temperature in the tire width direction of the tire 3 in the initial durability test condition as shown in FIG. Distribution, that is, surface temperature distribution at a rotational speed of 120 km / h is acquired.

  Next, the next durability test condition is set (step ST104). Specifically, with the input means 71, the tire size, air pressure, load, and camber angle are made constant among the initial durability test conditions, and a rotational speed equal to or higher than the initial rotational speed is input. That is, the next endurance test condition is one in which only the rotation speed is changed as compared with the initial endurance test condition. The detection device 6 increases the rotation speed of the test drum 2 and increases the rotation speed of the tire 3 based on the input next durability test condition. Here, for example, as shown in FIG. 5, the rotation speed is set to 120 km / h to 150 km / h. Thereby, the tire 3 is set to the next durability test condition.

  Next, the surface temperature distribution acquisition unit 64 of the processing unit 62 acquires the surface temperature distribution in the next durability test condition (step ST105). With the tire 3 set to the next durability test condition, the surface temperature distribution of the tire 3 is measured by the temperature sensor 5. The surface temperature distribution acquisition unit 64 acquires the surface temperature distribution data measured and output to the detection device 6 so that the surface temperature distribution in the tire width direction of the tire 3 in the next durability test condition as shown in FIG. That is, the surface temperature distribution at a rotational speed of 150 km / h is acquired.

  Next, the surface temperature distribution difference calculation unit 65 of the processing unit 62 calculates the surface temperature distribution difference (step ST106). Specifically, the surface temperature distribution difference, which is the difference between the surface temperature distribution in the next durability test condition and the surface temperature distribution in the previous durability test condition (including the initial durability test condition) before this next durability test condition. Is calculated. Here, for example, the surface temperature distribution difference when the rotational speed is changed from 120 km / h to 150 km / h is calculated. As shown in FIG. 6, the surface temperature difference is different in the surface temperature difference depending on each position of the tire 3 in the tire width direction. That is, the surface temperature distribution difference calculation unit 65 calculates the temperature change at each position in the tire width direction from the previous durability test condition to the next durability test condition.

Next, the failure temperature index calculation unit 66 of the processing unit 62 calculates the failure temperature index ΔT (step ST107). First, the failure temperature index calculation unit 66 calculates an average value Tave in the tire width direction, which is a distribution value Ts based on the calculated surface temperature distribution difference. Next, the failure temperature index calculation unit 66 acquires the maximum value Tmax of the surface temperature difference at each position in the tire width direction from the calculated surface temperature distribution difference. Then, the failure temperature index ΔT is calculated from the following equation (2). That is, the failure temperature index calculation unit 66 calculates the failure temperature index ΔT based on the average value Tave in the tire width direction and the maximum value Tmax of the surface temperature distribution difference. The failure temperature index ΔT is a value obtained by comparing the entire surface temperature distribution difference of the tire 3 in the tire width direction with the maximum value Tmax of the surface temperature distribution difference of the tire 3 in the tire width direction.
ΔT = Tmax / Tave (2)

  Next, failure determination unit 68 of processing unit 62 determines whether or not ΔT> ΔTc, that is, whether or not failure temperature index ΔT exceeds failure predicted temperature index ΔTc (step ST108). Here, when the failure temperature index ΔT is equal to or less than the predicted failure temperature index ΔTc, the above steps ST104 to ST108 are repeated until the failure temperature index ΔT exceeds the failure prediction temperature index ΔTc. That is, the following endurance test conditions in which arbitrary elements are further changed from the following endurance test conditions are set, the surface temperature distribution in the tire width direction of the tire 3 is obtained, the surface temperature distribution difference is calculated, and this surface temperature distribution ΔT is further calculated from the difference, and it is repeatedly determined whether ΔT> ΔTc. Here, for example, each durability test condition in which the rotational speed is increased from 150 km / h to 30 km / h is set, and as shown in FIG. 7, the surface temperature distribution when the rotational speed is increased by 30 km / h is obtained. To do. Then, after increasing the rotational speed by 30 km / h, the surface temperature distribution difference is calculated from the surface temperature distribution before and after, and as shown in FIG. 8, the failure temperature index ΔT is further calculated from the surface temperature distribution difference, It is repeated to determine whether or not ΔT> ΔTc. Therefore, it is calculated from the surface temperature distribution difference between the surface temperature distribution in any endurance test condition and the surface temperature distribution in the previous endurance test condition before this arbitrary endurance test condition among the endurance test conditions with arbitrary elements changed. Iterates until the failure temperature index ΔT thus made exceeds the failure prediction temperature index ΔTc.

  Next, when the failure determination unit 68 determines that the failure temperature index ΔT exceeds the failure predicted temperature index ΔTc, the failure detection unit 69 of the processing unit 62 detects a failure of the tire 3 (step ST109). Here, when detecting the failure detection unit 69, the detection device 6 may cause the display means 72 to display the endurance test condition in which the tire 3 has failed, the position in the tire width direction that has failed, and the like. Further, the alarm may be generated by stopping the rotation of the test drum 2. In Example 1, as shown in FIG. 8, the failure temperature index ΔT when the rotational speed is changed from 270 km / h to 300 km / h exceeds the failure predicted temperature index ΔTc. That is, the tire 3 can ensure durability if the rotational speed is less than 270 km / h.

  As described above, the tire durability test method in Example 1 detects a tire failure by comparing the entire surface temperature distribution difference of the tire 3 with the maximum value Tmax of the surface temperature distribution difference of the tire 3. That is, even when the surface temperature of the entire tire varies depending on the position by continuously changing any element of the durability test conditions in the tire durability test of the tire 3, the entire difference in the surface temperature distribution of the tire Since the tire failure is detected by the change in the maximum value Tmax with respect to the tire failure, the tire failure can be reliably detected at the initial stage.

  In the first embodiment, the failure prediction temperature index ΔTc is determined based on the failure temperature index ΔT in the previous tire durability test, but the present invention is not limited to this. FIG. 9 is a flowchart of another tire durability test method according to the first embodiment. As shown in the figure, the predicted failure temperature index ΔTc may be determined based on the most recently calculated failure temperature index ΔT. The following describes another tire durability test method shown in FIG. The other tire durability test method according to Example 1 shown in FIG. 9 has the same basic configuration as the tire durability test method according to Example 1 shown in FIG.

  First, as shown in FIG. 9, in the other tire durability test method according to the first embodiment, initial durability test conditions are first set (step ST110). Next, the surface temperature distribution acquisition unit 64 of the processing unit 62 acquires the surface temperature distribution under the initial durability test conditions (step ST111). Next, the next durability test condition is set (step ST112). Next, the surface temperature distribution acquisition unit 64 of the processing unit 62 acquires the surface temperature distribution in the next durability test condition (step ST113). Next, the surface temperature distribution difference calculation unit 65 of the processing unit 62 calculates the surface temperature distribution difference (step ST114). Next, the failure temperature index calculation unit 66 of the processing unit 62 calculates the failure temperature index ΔT (step ST115).

Next, failure determination unit 68 of processing unit 62 determines whether or not ΔT> ΔTc, that is, whether or not failure temperature index ΔT exceeds failure predicted temperature index ΔTc (step ST116). Here, when the failure temperature index ΔT is equal to or less than the failure prediction temperature index ΔTc, the failure prediction temperature index determination unit 67 of the processing unit 62 determines the failure prediction temperature index ΔTc (step ST118). Specifically, the predicted failure temperature index ΔTc is calculated by the following equation (3). That is, a predetermined multiple of the latest failure temperature index ΔT calculated by the failure temperature index calculation unit 66 is defined as a failure predicted temperature index ΔTc. In the first embodiment, the predicted failure temperature index ΔTc is determined to be 1.5 times the failure temperature index ΔT, but is not limited to this, and is 1.5 to 2 times depending on the tire durability test conditions. It may be determined within a range of .0 times. Here, since the failure prediction temperature index ΔTc with respect to the first failure temperature index ΔT is not determined by the failure prediction temperature index determination unit 67, a predetermined value may be set as ΔTc, or a difference in calculation of the first failure temperature index ΔT. In this case, step ST118 may be directly executed without determining whether or not ΔT> ΔTc by the failure determination unit 68.
ΔTc = ΔT × 1.5 (3)

  Next, steps ST112 to ST118 are repeated until the failure temperature index ΔT exceeds the failure prediction temperature index ΔTc. That is, the following endurance test conditions in which arbitrary elements are further changed from the following endurance test conditions are set, the surface temperature distribution in the tire width direction of the tire 3 is obtained, the surface temperature distribution difference is calculated, and this surface temperature distribution ΔT is further calculated from the difference, and it is repeatedly determined whether ΔT> ΔTc. If the failure temperature index ΔT is equal to or less than the predicted failure temperature index ΔTc, step ST118 is further repeated. That is, the determination of the failure predicted temperature index ΔTc from the latest calculated failure temperature index ΔT and the above equation (3) is repeated.

  Next, when the failure determination unit 68 determines that the failure temperature index ΔT exceeds the failure predicted temperature index ΔTc, the failure detection unit 69 of the processing unit 62 detects a failure of the tire 3 (step ST117). As described above, also in the other tire durability test methods in Example 1, the surface temperature of the entire tire is changed by continuously changing any element of the durability test conditions in the tire durability test of the tire 3. Even when the difference varies depending on the tire, the tire failure is detected by the change in the maximum value Tmax with respect to the entire difference in tire surface temperature distribution. Therefore, the tire failure can be reliably detected at the initial stage. .

  FIG. 10 is a diagram illustrating a configuration example of a tire durability test apparatus that executes the tire durability test method according to the second embodiment. FIG. 11 is a diagram illustrating a configuration example of the detection apparatus according to the second embodiment. The tire durability test apparatus 1-2 according to Example 2 shown in FIGS. 10 and 11 is different from the tire durability test apparatus 1-1 according to Example 2 shown in FIGS. The surface shape of the tire 3, that is, the profile line of the tire 3 is measured by the shape measuring sensor 8 instead of measuring the surface temperature of the tire 3. The basic configuration of the tire durability test apparatus 1-2 according to the second embodiment is substantially the same as the basic configuration of the tire durability test apparatus 1-1 according to the first embodiment, and the description thereof is omitted.

  The shape measuring sensor 8 is a profile measuring means, for example, a non-contact type shape measuring sensor such as a shape measuring device using a laser beam, and can measure the surface shape of the tire 3, that is, the profile. The shape measuring sensor 8 is arranged so as to face the tire 3 and continuously measures the profile of the tire 3 rotated by the test drum 2, and the profile image of the surface of the tire 3, that is, the profile distribution of the tire 3 is profiled. The distribution data is continuously output to the detection device 9.

  FIG. 12 is a flowchart of the tire durability test method according to the second embodiment. FIG. 13 is a diagram showing a profile distribution in an initial durability test condition. FIG. 14 is a diagram showing a profile distribution in the initial and subsequent durability test conditions. FIG. 15 is a diagram showing a profile distribution difference. FIG. 16 is a diagram showing a profile distribution under each durability test condition. FIG. 17 is a diagram illustrating the relationship between the failure displacement index and the failure predicted displacement index.

  First, as shown in FIG. 12, in the tire durability test method according to the second embodiment, initial durability test conditions are first set (step ST201). Specifically, the tire size, air pressure, load, and initial rotation speed are input as initial durability test conditions by the input means 71. Here, for example, the tire size is 225 / 45ZR17, the air pressure is 230 kPa, the load is 4 kN, and the initial rotational speed is 140 km / h. The detection device 9 rotates the test drum 2 and moves or rotates the support device 4 based on the inputted initial durability test conditions. Thereby, the tire 3 is set to the initial durability test conditions.

  Next, the failure predicted displacement index determining unit 97 of the processing unit 92 of the detection device 9 determines the failure predicted displacement index ΔDc (step ST202). Here, the storage unit 93 stores a failure displacement index ΔD, which will be described later, in each durability test condition in the tire durability test before the current tire durability test. The failure predictive displacement index determination unit 97 has a durability test condition that is the same as or close to the current tire durability test condition (mainly the initial tire durability test condition) among the durability test conditions stored in the storage unit 93. The fault displacement index ΔD is acquired. Then, the failure prediction displacement index determination unit 97 includes a failure displacement index ΔDe when the failure of the tire 3 is detected in the acquired failure displacement index ΔD, and a failure displacement index ΔDb before detecting the failure of the tire 3. Based on the above, the failure prediction displacement index ΔDc is determined. Note that a failure displacement index ΔD, which will be described later, in each durability test condition in the previous tire durability test may be stored in a database provided separately from the detection device 9 instead of the storage unit 93. In this case, the detection device 9 and the database are connected via the input / output port 91, and the failure prediction displacement index determination unit 97 appropriately accesses the database.

  Here, the failure predicted displacement index ΔDc is preferably in the range of 1.5 to 5.0 when a failure displacement index ΔD described later is calculated by the following equation (4). This is because if the value is less than 1.5, the maximum value Dmax with respect to the entire profile distribution difference of the tire 3 is small, so the local temperature change is small with respect to the temperature change in the entire width direction of the tire 3 and the tire 3 breaks down. Because it is not. Further, if the value exceeds 5.0, the maximum value Dmax for the entire profile distribution difference of the tire 3 is large, so that the local temperature change becomes too large with respect to the temperature change in the entire width direction of the tire 3, and the tire 3 fails. This is because cannot be detected in the initial stage.

  Next, the profile distribution acquisition unit 94 of the processing unit 92 acquires a profile distribution under initial durability test conditions (step ST203). With the tire 3 set to the initial durability test conditions, the profile distribution of the tire 3 is measured by the shape measuring sensor 8. The profile distribution acquisition unit 94 acquires the profile distribution data measured and output to the detection device 9 to obtain the profile distribution in the tire width direction of the tire 3 in the initial durability test condition, as shown in FIG. A profile distribution at a rotational speed of 140 km / h is acquired.

  Next, the next durability test condition is set (step ST204). Specifically, the input means 71 inputs a rotation speed equal to or higher than the initial rotation speed with the tire size, air pressure, and load being constant among the initial durability test conditions. That is, the next endurance test condition is one in which only the rotation speed is changed as compared with the initial endurance test condition. The detection device 9 increases the rotational speed of the test drum 2 and increases the rotational speed of the tire 3 based on the input next durability test condition. Here, for example, as shown in FIG. 14, the rotation speed is set to 140 km / h to 180 km / h. Thereby, the tire 3 is set to the next durability test condition.

  Next, the profile distribution acquisition unit 94 of the processing unit 92 acquires a profile distribution under the next durability test condition (step ST205). With the tire 3 set to the next durability test condition, the profile distribution of the tire 3 is measured by the shape measuring sensor 8. The profile distribution acquisition unit 94 acquires the profile distribution data measured and output to the detection device 9 to obtain the profile distribution in the tire width direction of the tire 3 in the next durability test condition, that is, rotation as shown in FIG. A profile distribution at a speed of 180 km / h is acquired.

  Next, the profile distribution difference calculation unit 95 of the processing unit 92 calculates a profile distribution difference (step ST206). Specifically, the profile distribution difference that is the difference between the profile distribution in the next durability test condition and the profile distribution in the previous durability test condition (including the initial durability test condition) before this next durability test condition is calculated. . Here, for example, the profile distribution difference when the rotational speed is changed from 140 km / h to 180 km / h is calculated. As shown in FIG. 15, the profile distribution difference differs depending on the position of the tire 3 in the tire width direction. That is, the profile distribution difference calculation unit 95 calculates a temperature change at each position in the tire width direction from the previous durability test condition to the next durability test condition.

Next, the failure displacement index calculation unit 96 of the processing unit 92 calculates the failure displacement index ΔD (step ST207). First, the failure displacement index calculation unit 96 calculates an average value Dave in the tire width direction, which is a distribution value Ds based on the calculated profile distribution difference. Next, the failure displacement index calculation unit 96 acquires the maximum value Dmax of the profile difference at each position in the tire width direction from the calculated profile distribution difference. Then, the failure displacement index ΔD is calculated from the following equation (4). That is, the failure displacement index calculation unit 96 calculates the failure displacement index ΔD based on the average value Dave in the tire width direction and the maximum value Dmax of the profile distribution difference. The failure displacement index ΔD is a value obtained by comparing the entire profile distribution difference of the tire 3 in the tire width direction with the maximum value Dmax of the profile distribution difference of the tire 3 in the tire width direction.
ΔD = Dmax / Dave (4)

  Next, failure determination unit 98 of processing unit 92 determines whether or not ΔD> ΔDc, that is, whether or not failure displacement index ΔD exceeds failure predicted displacement index ΔDc (step ST208). Here, when the failure displacement index ΔD is equal to or less than the failure predicted displacement index ΔDc, the above steps ST204 to ST208 are repeated until the failure displacement index ΔD exceeds the failure predicted displacement index ΔDc. That is, the following endurance test conditions in which arbitrary elements are further changed from the following endurance test conditions are set, the profile distribution in the tire width direction of the tire 3 is acquired, the profile distribution difference is calculated, and ΔD is calculated from the profile distribution difference. Is further calculated, and it is repeated whether or not ΔD> ΔDc. Here, for example, each durability test condition in which the rotational speed is increased from 180 km / h by 40 km / h is set, and as shown in FIG. 16, the profile distribution when the rotational speed is increased by 40 km / h is obtained. . Then, the profile distribution difference is calculated from the profile distribution after the rotation speed is increased by 40 km / h and before, and as shown in FIG. 17, the failure displacement index ΔD is further calculated from the profile distribution difference, and ΔD> ΔDc It repeats judging whether it is. Therefore, the failure calculated from the profile distribution difference between the profile distribution in any endurance test condition and the profile distribution in the previous endurance test condition before this arbitrary endurance test condition among the endurance test conditions with arbitrary elements changed Repeat until the displacement index ΔD exceeds the failure prediction displacement index ΔDc.

  Next, when the failure determination unit 98 determines that the failure displacement index ΔD exceeds the failure predicted displacement index ΔDc, the failure detection unit 99 of the processing unit 92 detects a failure of the tire 3 (step ST209). Here, when detecting the failure detection unit 99, the detection device 9 may cause the display means 72 to display the endurance test condition in which the tire 3 has failed, the position in the tire width direction that has failed, and the like. Further, the alarm may be generated by stopping the rotation of the test drum 2. In Example 1, as shown in FIG. 17, the failure displacement index ΔD when the rotational speed is changed from 260 km / h to 300 km / h exceeds the failure predicted displacement index ΔDc. That is, the tire 3 can ensure durability if the rotational speed is less than 260 km / h.

  As described above, the tire durability test method in Example 2 detects the failure of the tire by comparing the entire profile distribution difference of the tire 3 with the maximum value Dmax of the profile distribution difference of the tire 3. That is, by continuously changing any element of the durability test conditions in the tire durability test of the tire 3, even when the profile of the entire tire varies depending on the position, the maximum of the profile distribution difference of the tire is the maximum. Since the tire failure is detected by the change in the value Dmax, the tire failure can be reliably detected at the initial stage.

  In the second embodiment, the predicted failure displacement index ΔDc is determined based on the failure displacement index ΔD in the previous tire durability test, but the present invention is not limited to this. FIG. 18 is a flowchart of another tire durability test method according to the second embodiment. As shown in the figure, the predicted failure displacement index ΔDc may be determined based on the most recently calculated failure displacement index ΔD. The following describes another tire durability test method shown in FIG. The other tire durability test method according to Example 2 shown in FIG. 18 is the same as the tire durability test method according to Example 2 shown in FIG.

  First, as shown in FIG. 18, in the other tire durability test method according to the example 2, first, an initial durability test condition is set (step ST210). Next, the profile distribution acquisition unit 94 of the processing unit 92 acquires the profile distribution in the initial durability test condition (step ST211). Next, the next durability test condition is set (step ST212). Next, the profile distribution acquisition unit 94 of the processing unit 92 acquires a profile distribution under the next durability test condition (step ST213). Next, the profile distribution difference calculation unit 95 of the processing unit 92 calculates a profile distribution difference (step ST214). Next, the failure displacement index calculation unit 96 of the processing unit 92 calculates the failure displacement index ΔD (step ST215).

Next, failure determination unit 98 of processing unit 92 determines whether or not ΔD> ΔDc, that is, whether or not failure displacement index ΔD exceeds failure predicted displacement index ΔDc (step ST216). Here, when the failure displacement index ΔD is equal to or less than the failure prediction displacement index ΔDc, the failure prediction displacement index determination unit 97 of the processing unit 92 determines the failure prediction displacement index ΔDc (step ST218). Specifically, the failure prediction displacement index ΔDc is calculated by the following equation (5). That is, a predetermined multiple of the latest failure displacement index ΔD calculated by the failure displacement index calculation unit 96 is set as a failure predicted displacement index ΔDc. In Example 2, the failure prediction displacement index ΔDc is determined to be 1.5 times the failure displacement index ΔD, but is not limited to this, and is 1.5 times to 2 depending on the tire durability test conditions. It may be determined within a range of .0 times. Here, since the failure predicted displacement index ΔDc with respect to the first failure displacement index ΔD is not determined by the failure predicted displacement index determining unit 97, a predetermined value may be set as ΔDc, or a difference in calculation of the first failure displacement index ΔD. In this case, step ST218 may be directly executed without determining whether or not ΔD> ΔDc by the failure determination unit 98.
ΔDc = ΔD × 1.5 (5)

  Next, steps ST212 to ST218 are repeated until the failure displacement index ΔD exceeds the failure predicted displacement index ΔDc. That is, the following endurance test conditions in which arbitrary elements are further changed from the following endurance test conditions are set, the profile distribution in the tire width direction of the tire 3 is acquired, the profile distribution difference is calculated, and ΔD is calculated from the profile distribution difference. Is further calculated, and it is repeated whether or not ΔD> ΔDc. If the failure displacement index ΔD is equal to or less than the failure predicted displacement index ΔDc, step ST218 is further repeated. That is, the determination of the failure predicted displacement index ΔDc from the most recently calculated failure displacement index ΔD and the above equation (5) is repeated.

  Next, when the failure determination unit 98 determines that the failure displacement index ΔD exceeds the failure predicted displacement index ΔDc, the failure detection unit 99 of the processing unit 92 detects a failure of the tire 3 (step ST217). As described above, also in the other tire durability test methods in Example 2, in the tire durability test of the tire 3, by continuously changing any element among the durability test conditions, the profile of the entire tire depends on the position. Even in the case of changing differently, the tire failure is detected by the change of the maximum value Dmax with respect to the entire tire profile distribution difference, so that the tire failure can be reliably detected at the initial stage.

  In the first and second embodiments, the average value Tave is used as the distribution value Ts based on the calculated surface temperature distribution difference, but the present invention is not limited to this. For example, a standard deviation calculated from the calculated surface temperature distribution difference may be used as the distribution value Ts based on the calculated surface temperature distribution difference.

  In the first and second embodiments, a failure of the tire 3 may be detected based on the surface temperature distribution difference and the profile distribution difference of the tire 3. That is, the failure of the tire 3 may be detected when at least one of the failure temperature index ΔT and the failure displacement index ΔD exceeds the failure prediction temperature index ΔTc or the failure prediction displacement index ΔDc. As a result, the tire failure can be detected more reliably at the initial stage.

  In the first and second embodiments, a failure of the tire 3 may be detected not only based on the tire width direction of the tire 3 but also on the surface temperature distribution difference or profile distribution difference in the tire circumferential direction. Thereby, not only the tire width direction but also the position of the failure of the tire 3 in the tire circumferential direction can be detected.

  As described above, the tire endurance test method, the tire endurance test apparatus, and the tire endurance test program according to the present invention are useful for testing the endurance performance of the tire, and in particular, reliably detect a tire failure at an early stage. Suitable for doing.

It is a figure which shows the structural example of the tire durability test apparatus which performs the tire durability test method concerning Example 1. FIG. 1 is a diagram illustrating a configuration example of a detection device according to Embodiment 1. FIG. It is a figure which shows the flowchart of the tire durability test method concerning Example 1. FIG. It is a figure which shows the surface temperature distribution in the initial durability test conditions. It is a figure which shows the surface temperature distribution in the initial stage and the following endurance test conditions. It is a figure which shows a surface temperature distribution difference. It is a figure which shows the surface temperature distribution in each durability test condition. It is a figure which shows the relationship between a failure temperature index and a failure prediction temperature index. It is a figure which shows the flowchart of the other tire durability test method concerning Example 1. FIG. It is a figure which shows the structural example of the tire durability test apparatus which performs the tire durability test method concerning Example 2. FIG. FIG. 6 is a diagram illustrating a configuration example of a detection apparatus according to a second embodiment. It is a figure which shows the flowchart of the tire durability test method concerning Example 2. FIG. It is a figure which shows profile distribution in the initial stage durability test conditions. It is a figure which shows the profile distribution in the initial stage and the following endurance test conditions. It is a figure which shows a profile distribution difference. It is a figure which shows the profile distribution in each durability test condition. It is a figure which shows the relationship between a failure displacement index and a failure prediction displacement index. It is a figure which shows the flowchart of the other tire durability test method concerning Example 2. FIG.

Explanation of symbols

1-1, 1-2 Tire durability test device 2 Test drum 3 Tire 4 Support device 5 Temperature sensor (surface temperature measuring means)
6 Detection Device 61 Input / Output Port 62 Processing Unit 63 Storage Unit 64 Surface Temperature Distribution Acquisition Unit 65 Surface Temperature Distribution Difference Calculation Unit (Surface Temperature Distribution Difference Calculation Means)
66 Failure temperature index calculation unit (failure temperature index calculation means)
67 Failure prediction temperature index determination unit (failure prediction temperature index determination means)
68 Failure temperature determination unit (failure temperature determination means)
69 Failure detection unit (failure detection means)
7 Input / output device 71 Input means 72 Display means 8 Shape measuring sensor (profile measuring means)
DESCRIPTION OF SYMBOLS 9 Detection apparatus 91 Input / output port 92 Processing part 93 Storage part 94 Profile distribution acquisition part 95 Profile distribution difference calculation part (Profile distribution difference calculation means)
96 Failure displacement index calculation unit (failure displacement index calculation means)
97 Failure predicted displacement index determining unit (failure predicted displacement index determining means)
98 Failure displacement determination unit (failure displacement determination means)
99 Failure detection unit (failure detection means)

Claims (10)

A surface temperature distribution acquisition procedure for continuously changing an arbitrary element from a durability test condition including a plurality of elements and acquiring a tire surface temperature distribution in each durability test condition;
A surface temperature distribution difference calculation procedure for calculating a surface temperature distribution difference between a surface temperature distribution in an arbitrary endurance test condition and a surface temperature distribution in a previous endurance test condition before the arbitrary endurance test condition among the respective endurance test conditions; ,
A failure temperature index calculation procedure for calculating a failure temperature index ΔT based on the distribution value Ts based on the calculated surface temperature distribution difference and the maximum value Tmax of the surface temperature distribution difference;
A failure prediction temperature index determination procedure for determining a failure prediction temperature index ΔTc based on the failure temperature index ΔT calculated in the previous tire durability test or the failure temperature index ΔT calculated most recently;
A failure temperature determination procedure for determining whether the failure temperature index ΔT exceeds the failure prediction temperature index ΔTc;
A failure detection procedure for detecting a failure when the failure temperature index ΔT exceeds the predicted failure temperature index ΔTc;
A tire durability test method comprising:   The failure prediction temperature index determination procedure includes a failure temperature index ΔTe when a failure is detected among the failure temperature indices ΔT calculated in the previous tire durability test and a failure temperature index ΔTb before the failure is detected. 2. The tire durability test method according to claim 1, wherein a failure prediction temperature index [Delta] Tc is determined based on the tire failure temperature index [Delta] Tc.   3. The tire durability test method according to claim 1, wherein the failure prediction temperature index determination procedure determines the failure prediction temperature index ΔTc within a range of 1.5 to 5.0.   The failure prediction temperature index determination procedure determines the failure prediction temperature index ΔTc to be 1.5 to 2.0 times the most recently calculated failure temperature index ΔT. Tire durability test method. The distribution value Ts based on the calculated surface temperature distribution difference is an average value Tave of the calculated surface temperature distribution difference,
5. The tire durability test method according to claim 1, wherein the failure temperature index calculation procedure calculates a failure temperature index ΔT by the following equation.
ΔT = Tmax / Tave (1)   The surface temperature distribution acquisition procedure acquires the surface temperature distribution of the tire under each of the durability test conditions in at least one of the tire width direction and the tire circumferential direction. The tire endurance test method described. A profile distribution acquisition procedure for acquiring a tire profile distribution in each of the durability test conditions;
A profile distribution difference calculation procedure for calculating a profile distribution difference between a profile distribution in an arbitrary endurance test condition and a profile distribution in a previous endurance test condition before the arbitrary endurance test condition among the respective endurance test conditions;
A failure displacement index calculation procedure for calculating a failure displacement index ΔD based on the distribution value Ds based on the calculated profile distribution difference and the maximum value Dmax of the profile distribution difference;
A failure prediction displacement index determination procedure for determining a failure prediction displacement index ΔDc based on the failure displacement index ΔD calculated in the previous tire durability test or the most recently calculated failure displacement index ΔD;
A failure displacement determination procedure for determining whether the failure displacement index ΔD exceeds the failure predicted displacement index ΔDc;
Further including
The failure detection procedure detects a failure at least in the case where either the failure temperature index ΔT exceeds the failure prediction temperature index ΔTc or the failure displacement index ΔD exceeds the failure prediction displacement index ΔDc. The tire durability test method according to any one of claims 1 to 6.   A tire endurance test program for causing a computer to execute the tire multi-feed test method according to any one of claims 1 to 7. Surface temperature measuring means for continuously changing an arbitrary element from a durability test condition consisting of a plurality of elements, and measuring a tire surface temperature distribution under each durability test condition;
A surface temperature distribution difference calculating means for calculating a surface temperature distribution difference between a surface temperature distribution in an arbitrary endurance test condition and a surface temperature distribution in a previous endurance test condition before the arbitrary endurance test condition among the respective endurance test conditions; ,
A failure temperature index calculating means for calculating a failure temperature index ΔT based on the distribution value Ts based on the calculated surface temperature distribution difference and the maximum value Tmax of the surface temperature distribution difference;
Failure prediction temperature index determination means for determining the failure prediction temperature index ΔTc based on the failure temperature index ΔT calculated in the previous tire durability test or the failure temperature index ΔT calculated most recently;
Failure temperature determination means for determining whether the failure temperature index ΔT exceeds the failure prediction temperature index ΔTc;
Failure detection means for detecting a failure when the failure temperature index ΔT exceeds the failure prediction temperature index ΔTc;
A tire durability testing apparatus comprising: A profile distribution acquisition procedure for continuously changing an arbitrary element from a durability test condition including a plurality of elements and acquiring a tire profile distribution in each durability test condition;
A profile distribution difference calculation procedure for calculating a profile distribution difference between a profile distribution in an arbitrary endurance test condition and a profile distribution in a previous endurance test condition before the arbitrary endurance test condition among the respective endurance test conditions;
A failure displacement index calculation procedure for calculating a failure displacement index ΔD based on the distribution value Ds based on the calculated profile distribution difference and the maximum value Dmax of the profile distribution difference;
A failure prediction displacement index determination procedure for determining a failure prediction displacement index ΔDc based on the failure displacement index ΔD calculated in the previous tire durability test or the most recently calculated failure displacement index ΔD;
A failure displacement determination procedure for determining whether the failure displacement index ΔD exceeds the failure predicted displacement index ΔDc;
A failure detection procedure for detecting a failure when the failure displacement index ΔD exceeds the failure predicted displacement index ΔDc;
A tire durability test method comprising:

Images