JP4335740B2 - Tire running test method and tire running test apparatus - Google Patents

Description

  The present invention relates to a tire running test method and a tire running test apparatus for detecting a failure by running a tire on a road surface.

  Conventionally, durability is tested by running a tire at a high speed.

  In this test, generally, when detection rods are arranged at regular intervals (for example, 6 mm) on the outer side of the tire and local expansion of the tire is detected by this detection rod, it is determined that a failure such as chunk or separation has occurred in the tire. , Tire running is stopped.

  However, there is a problem that the accuracy of detecting a failure is not so good. In addition, there is a problem that variations in accuracy occur depending on the person in charge of the test when installing the detection rod.

  There was also a problem of false detection. For example, if the growth of the outer diameter of the tire due to high-speed rotation is large, it is judged that the tire has failed even though it has not failed. In the initial stage of failure, the failure part cannot be expanded due to chunking without expansion. In addition, when the degree of expansion of the failed part is low, it is determined that it has failed but has failed. Furthermore, the frequency of false detection varies depending on the rubber type.

  As a countermeasure for these problems, it is disclosed in Patent Document 1 that the presence or absence of a tire failure is determined by monitoring infrared rays radiated from the tread surface, but the problem of detection accuracy and false detection is solved. It is difficult to think.

Further, it is conceivable to detect a failure such as a chunk based on the temperature change of the tread tread portion by measuring the temperature of the tread tread portion (see, for example, Patent Document 2). It is difficult to specify the location of the failure only by detecting the above.
US3807226 Japanese Patent Laid-Open No. 2001-264041

  In view of the above facts, an object of the present invention is to provide a tire running test method and a tire running test apparatus that can evaluate a tire failure caused by a tire running test with high accuracy and with few false detections.

  The inventor has confirmed through experiments that when a tire is run on the road surface, the temperature of the portion where the chunk is generated rises locally compared to the surrounding area.

  It was also found that the temperature of the tread tread portion (local temperature increase portion) where the temperature locally increased was 90 ° C. or higher. In addition, when the local temperature rising part is still in the nuclear stage, it is about 75 ° C., and it takes about 7 seconds on average for this part to rise to 90 ° C., and It was also found that the temperature difference between the temperature at the local temperature rise portion (particularly the core portion) and the tread surface portion in the circumferential direction becomes a certain value or more.

  Therefore, the present inventor considered that when a temperature increase locally occurs, it is possible to easily determine which part has the chunk even if the tire travel is stopped. .

  As a result of intensive studies, the idea of using the fact that the portion where the chunk is generated spread by continuing running for a while even if the chunk is generated has been further studied, and the present invention has been completed. .

  According to the first aspect of the present invention, the temperature of the tread tread portion of the tire is increased by running the tire on the road surface, the temperature distribution of the tread tread portion is measured, and the local temperature on the tread tread portion is measured. When it is detected that the rising portion has occurred, the tire traveling is stopped after a predetermined time has elapsed.

  When tires are running on the road surface, unless there is a local temperature rise in the tread surface, there is usually no failure such as chunks or separation in the tire, and there is locality in the tread surface. When the temperature rise portion occurs, there is a high possibility that a failure such as chunk or separation has occurred. Therefore, even if it is detected that a local temperature rising portion has occurred, the tire running is continued for a predetermined time and the portion where a failure such as chunk or separation occurs is widened. It is easy to find a part where separation or the like occurs by visual inspection or the like. As a result, the failure can be evaluated with high accuracy and with few false detections, which is optimal for evaluating a high-performance tire.

  Further, when the tire durability test is performed, the durability time can be appropriately obtained by subtracting the predetermined time from the traveling time when the tire traveling is stopped. This is remarkably useful in examining the difference in failure occurrence location due to the difference in tire structure and rubber type.

  According to a second aspect of the present invention, when a portion of the tread surface that is higher than the average temperature in the circumferential direction by a predetermined temperature or more is detected, it is determined that the local temperature increasing portion has occurred. Features.

  The predetermined temperature is set according to the tire type, the maximum temperature of the nucleus at the initial stage of failure, and the like. For example, when the maximum temperature of the nucleus at the initial stage of failure is 75 ° C., the predetermined temperature is set to about 7 to 11 ° C. When the maximum temperature of the nucleus at the initial stage of failure is 75 ° C., the predetermined temperature is set to about 25 ° C.

  According to the second aspect of the present invention, it can be easily determined with high accuracy that a local temperature rise has occurred.

  According to a third aspect of the present invention, when a portion having a temperature of 75 ° C. or higher occurs in the tread tread portion, it is determined that the local temperature increase portion has occurred.

  Thereby, it can be judged remarkably easily that the local temperature rise part generate | occur | produced.

  The invention according to claim 4 is characterized in that the predetermined time is set according to a tire type.

  As a result, it is possible to sufficiently widen the chunks, separations, and the like generated at the location where the local temperature rising portion is generated with a reasonable traveling time after the local temperature rising portion is generated. Therefore, it is possible to correctly obtain the durability time in the tire durability test, and it is possible to easily find the failure portion by visual inspection or the like even when the tire traveling is stopped. The predetermined time is often about 20 seconds.

  According to a fifth aspect of the present invention, there is provided a tire support means for rotatably supporting a tire, a road surface portion having a road surface on which the tread tread portion of the tire is brought into contact with and running the tire, the road surface portion and the tire. Driving means for driving at least one of the tires, temperature measuring means for measuring the temperature of the tread tread portion in a non-contact manner, and local measurement of the tread tread portion based on a measurement result by the temperature measuring means. Detection means for detecting a temperature rise portion, and control means for controlling the drive means to stop the rotation of the tire after a predetermined time has elapsed when the detection means detects the local temperature rise portion. It is characterized by having.

  In the invention according to claim 5, the temperature of the tread surface portion of the tire is increased by causing the tire to travel on the road surface by the driving means. At that time, the temperature of the tread surface is measured by the temperature measuring means.

  When the local temperature increase portion is detected by the detection means based on the measurement result of the temperature measurement means, the tire traveling is stopped after a predetermined time has elapsed by the control means.

  If a local temperature rise portion occurs in the tread surface, there is a high possibility that a failure such as chunk or separation has occurred. Therefore, even if it detects that the local temperature rise part generate | occur | produced in this way, the part in which the chunk, the separation, etc. have arisen can be extended by continuing tire driving | running for a predetermined time. Accordingly, a compact tire running test apparatus is realized in which, after stopping the tire running, a portion where chunks or separations are generated can be easily found by visual observation or the like. Further, when the tire durability test is performed, the durability time can be appropriately obtained by subtracting the predetermined time from the traveling time when the tire traveling is stopped.

  The invention described in claim 6 is characterized in that the temperature measuring means is a non-contact type radiation thermometer.

  Thereby, a temperature measurement means can be simplified and reduced in size.

  The invention described in claim 7 is characterized in that the radiation thermometer is a thermographic thermometer.

  Thereby, the temperature distribution of the tread surface can be visualized so as to be obvious at a glance.

  The invention according to claim 8 is characterized in that the road surface portion is a drum having the road surface on an outer peripheral surface side.

  Thereby, the structure of a road surface part can be made simple and small.

  Since the present invention has the above-described configuration, it is possible to evaluate a tire failure caused by a tire running test with high accuracy and with few erroneous detections.

  Hereinafter, embodiments will be described and embodiments of the present invention will be described. As shown in FIG. 1, a tire running test apparatus 10 according to an embodiment of the present invention is an apparatus suitable for a high-speed running test of a pneumatic tire, and a pneumatic tire 20 (hereinafter simply referred to as a tire 20). A tire support portion 22 that is rotatably supported, a drum 26 that makes the tire 20 run by contacting the tread surface portion 20T of the tire 20, and a motor 29 that drives the drum 26 to rotate the tire 20 at high speed.

  In addition, the tire running test apparatus 10 displays a thermographic radiation thermometer 14 that measures the temperature of the tread tread portion 20T in a non-contact manner and the temperature distribution of the tread tread portion 20T based on the measurement result of the radiation thermometer 14. A thermovision (image display device) 34 and a computer 32 that determines the presence or absence of a local temperature increase portion of the tread tread surface portion 20T based on the measurement result of the radiation thermometer 14 are provided.

  The tire support 22 holds the tire 20 in a freely rotatable manner and can be moved up and down by a hydraulic cylinder 24. A drum 26 is disposed below the tire support portion 22.

  The drum 26 has a road surface 26 </ b> S on the outer peripheral surface side, is rotatably supported by a bearing 28, and is rotated by a motor 29.

  The radiation thermometer 14 includes an infrared camera 30 that detects infrared rays emitted from a temperature measurement target (the tire 20 in the present embodiment). As the radiation thermometer 14, for example, TVS-8000 manufactured by Nippon Avionics Co., Ltd. can be used, but other types may be used.

  The infrared camera 30 photographs the tire 20, and temperature information (temperature measurement result) of the photographed tire 20 is output to the computer 32.

  The computer 32 includes a CPU (arithmetic unit), a ROM, a RAM (storage unit), and the like. The computer 32 calculates temperature information of the tire 20 photographed by the infrared camera 30 of the radiation thermometer 14. A tire image is displayed in which the level of temperature is indicated by density (or the level of temperature is divided by color). Further, the computer 32 is programmed to stop the rotation of the drum 26 after a predetermined time has elapsed (for example, after 20 seconds) when a local temperature increase portion of the tread tread surface portion 20T is detected.

  Hereinafter, the effect | action which performs the durability test of a tire with the tire running test apparatus 10 is demonstrated.

  The tire 20 is set on the tire support portion 22, and the tread surface portion 20 </ b> T of the tire 20 is brought into contact with the road surface 26 </ b> S of the drum 26. Moreover, the temperature measurement of the tread tread part 20T by the radiation thermometer 14 is started.

  Furthermore, the drum 26 is rotated at high speed by the motor 29. As a result, the tire 20 travels on the road surface 26S, and the temperature of the tread surface portion 20T increases.

  When the computer 32 detects the local temperature rise portion of the tread tread surface portion 20T, the tire 32 stops running by stopping the rotation of the drum 26 after a predetermined time has elapsed. The detection is set in the computer 32 so that, for example, it is determined that a portion having a temperature of 90 ° C. or more has been detected on the tread surface 20T.

  When a local temperature rise portion occurs in the tread surface portion 20T, there is a high possibility that a failure such as a chunk or separation has occurred. Therefore, even if the computer 32 detects that a local temperature rise has occurred in this way, the tire running is stopped by continuing the tire running for a predetermined time and widening the portion where chunks or separation occurs. Later, it is easy to find a portion where chunks or separation occurs by visual inspection or the like. Further, when the tire durability test is performed, the durability time can be appropriately obtained by subtracting the predetermined time from the traveling time when the tire traveling is stopped.

  Further, the above effect is obtained by extending and calculating the running time as described above, and the road surface 26S is formed on the outer peripheral surface side of the drum 26, so that the tire running can obtain such an effect. The configuration of the test apparatus 10 can be made compact.

  In place of the drum 26, as shown in FIG. 2, a drive drum 38 and a driven drum 40, and an endless belt 44 that spans both drums and has a road surface on the outer peripheral surface side may be provided.

<Experimental example>
In this experimental example, first, a durability test of a pneumatic tire was performed using the tire running test apparatus 10. The setting of the chunk 32 in the computer 32 is set so as to be detected when a portion having a temperature of 90 ° C. or higher is generated on the tread surface portion 20T.

  When some time has elapsed since the start of the running experiment, the temperature distribution of the tread tread surface portion 20T of the pneumatic tire 20 displayed by the thermovision 34 becomes as shown in FIG. Judged that it occurred. Then, the computer 32 stopped running of the pneumatic tire 20 by stopping the rotation of the drum 26 after 20 seconds.

  As shown in FIG. 4, a chunk 48 was generated on the tread surface portion 20 </ b> T of the pneumatic tire 20 taken out from the tire running test apparatus 10.

  When a durability test was performed on a plurality of tires by such a test method, about one chunk was formed on the tread tread surface of the tire that stopped running, as shown in FIG. Thus, the chunk detection accuracy was 100%.

  For comparison, a case where a test is performed by a conventional tire running test method using a detection rod will be described.

  In this conventional tire running test method, a detection instrument 84 having a plurality of detection rods 82 spaced apart by 6 mm in the tire width direction is disposed at a predetermined position outside the pneumatic tire 80 (see FIG. 6).

  Further, the pneumatic tire 80 was caused to travel, and when the detection rod 82 determined that a failure occurred in the tread surface portion 80T of the pneumatic tire 80, the tire traveling was stopped.

  Then, when the tread tread surface portion 80T of the pneumatic tire 80 was visually inspected, as shown in FIG. 7, it frequently occurred that many chunks 86 were scattered or no chunks were generated.

  When a durability test was performed on a plurality of tires using the conventional test method as described above, as shown in FIG. 8, the ratio at which one chunk was formed (that is, the ratio detected correctly) was 57%. The ratio that the chunk was not detected even though the chunk was formed inside the tread tread surface portion 80T was 17%, the false detection rate (a large number of chunks were generated on the tread tread surface). Or the ratio of having no chunks despite the occurrence of chunks) was 26%.

  The embodiments of the present invention have been described above with reference to the embodiments. However, the above embodiments are merely examples, and various modifications can be made without departing from the scope of the invention. Needless to say, the scope of rights of the present invention is not limited to the above embodiment.

1 is a schematic configuration diagram of a tire running test apparatus according to a first embodiment. It is a perspective view which shows the endless belt used with the modification of the tire running test apparatus which concerns on 1st Embodiment. It is a top view of the thermovision by which temperature distribution was displayed by the test using the tire running test device concerning a 1st embodiment. It is a partial side view showing a tread tread part of a pneumatic tire taken out from a tire running test device in a test using a tire running test device concerning a 1st embodiment. It is a graph which shows the detection accuracy of the chunk by the test using the tire running test device concerning a 1st embodiment. It is a partial side view which shows arrange | positioning a detection rod at a fixed space | interval in the width direction of a pneumatic tire by the conventional tire running test. It is a partial side view which shows the tread surface part of the pneumatic tire taken out from the tire running test apparatus in the conventional tire running test. It is a graph which shows the detection accuracy of the chunk by the conventional tire running test.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Tire running test apparatus 14 Radiation thermometer 20 Pneumatic tire (tire)
20T tread surface 22 tire support (tire support means)
26 Drum 26S Road surface 29 Motor (drive means)
32 Computer (detection means, control means)
38 Driving drum 44 Endless belt (road surface)

Claims (8)

While increasing the temperature of the tread tread portion of the tire by running the tire on the road surface, measuring the temperature distribution of the tread tread portion,
A tire running test method comprising: stopping tire running after elapse of a predetermined time when it is detected that a local temperature rising portion is generated on the tread surface portion.   The said tread tread part determines that the said local temperature rise part generate | occur | produced, if the part whose temperature is more than predetermined temperature compared with the average temperature of the circumferential direction is detected. Tire running test method.   2. The tire running test method according to claim 1, wherein when the portion having a temperature of 75 ° C. or more is generated on the tread surface portion, it is determined that the local temperature increasing portion is generated. 3.   The tire running test method according to any one of claims 1 to 3, wherein the predetermined time is set according to a tire type. Tire support means for rotatably supporting the tire;
A road surface portion having a road surface on which the tire runs by contacting the tread surface portion of the tire;
Driving means for rotating the tire by driving at least one of the road surface portion and the tire;
Temperature measuring means for measuring the temperature of the tread tread portion in a non-contact manner;
Detection means for detecting a local temperature increase portion of the tread surface portion based on a measurement result by the temperature measurement means;
Control means for controlling the drive means so as to stop the rotation of the tire after a lapse of a predetermined time when the local temperature increase portion is detected by the detection means;
A tire running test apparatus comprising:   6. The tire running test apparatus according to claim 5, wherein the temperature measuring means is a non-contact type radiation thermometer.   7. The tire running test apparatus according to claim 6, wherein the radiation thermometer is a thermographic thermometer.   The tire running test device according to any one of claims 5 to 7, wherein the road surface portion is a drum having the road surface on an outer peripheral surface side.

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