JP2008008695A - Method for setting of tire test condition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for setting of a tire test condition capable of determining whether or not tire performance satisfies a given level in a real car test by a laboratory test, not with a comparative evaluation between tires. <P>SOLUTION: A threshold for breakdown of a tire component is determined from a physical property of the broken tire component which is sampled from a broken tire in a real car test. A laboratory test is performed in a predetermined condition on a tire which has the same configuration with a tire for the real car test. When the tire for the laboratory test generates a breakdown in the same tire component with that for the real car test, and the physical property of the tire component shows the same level with the threshold, the predetermined condition is set as a laboratory test condition for the test tire. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for setting test conditions for a tire, and more specifically, it is not a relative evaluation for comparing tires, but a lab test to determine whether or not a tire performance satisfies a predetermined level in an actual vehicle test. The present invention relates to a method for setting tire test conditions.

In general, a pneumatic tire is fatigued due to an increase in travel distance and deterioration due to aging, and the physical properties of the tire constituent members are lowered, and eventually the tire is destroyed. There are various destructive tests and fatigue tests as such a lab test of a tire (a test that is performed by mounting a tire on a test apparatus, not a test that is actually performed by mounting a tire on a vehicle (actual vehicle test)) (for example, However, these tests are relative evaluations comparing tires, and it is difficult to determine superiority or inferiority depending on how the test conditions are selected. There is also a case. That is, in various conventional destructive tests and fatigue tests, there has been a problem that it is impossible to reliably determine whether or not the tire performance satisfies a predetermined level in the actual vehicle test.
JIS D4230

  An object of the present invention is to provide a tire test condition setting method that can reliably determine whether or not a tire performance satisfies a predetermined level in an actual vehicle test, rather than a relative evaluation comparing tires. There is.

  The tire test condition setting method of the present invention that achieves the above object is to determine a failure threshold value of the tire component member from a physical property value of the destroyed tire component sampled from a tire destroyed by an actual vehicle test, and A lab test is performed on a tire having the same configuration as the tire under a preset condition, the tire of the lab test breaks down in the same tire constituent member as the actual vehicle test, and the physical property value of the tire constituent member is the threshold value. When the same level is exhibited, the preset condition is set as a laboratory test condition of a test tire to be compared with the tire.

  According to the above-described present invention, by adopting the lab test conditions obtained as described above, if the tire constituent member of the test tire is broken before the lab test is completed, the test tire is an actual vehicle. It can be seen that the tire is inferior to the test tire (the tire in which the tire constituent member satisfies the predetermined level), that is, the tire performance (the tire constituent member) does not satisfy the predetermined level in the actual vehicle test. On the other hand, if no damage has occurred in the tire component of the test tire even after the laboratory test is completed, this test tire is superior to the tire of the actual vehicle test, that is, the tire performance (tire component) in the actual vehicle test is excellent. It can be seen that the tire satisfies the predetermined level.

  Therefore, it is possible to reliably determine whether or not the tire performance (tire constituent member) satisfies a predetermined level in the actual vehicle test, rather than the relative evaluation of simply comparing the tires.

  It is impossible to give a history that is exactly the same as the history of heat and mechanical energy applied to the pneumatic tire during running of the vehicle in the laboratory test. However, in general, as shown in FIG. 1, in a pneumatic tire, the physical properties of tire constituent members such as a belt layer and a carcass layer constituting the pneumatic tire are lowered with an increase in history (increase in travel distance and time). When it becomes lower than a certain physical property value (threshold value), destruction occurs.

  In addition, as shown in FIG. 2, when the input (mechanical energy to the tire) is large, the pneumatic tire is rapidly deteriorated in the physical properties of the tire constituent member, and breakage occurs quickly. Since the deterioration of the physical properties of the member progresses slowly, the occurrence of destruction is delayed and the life is prolonged. The physical property value of the tire constituent member when the destruction occurs is at the same level in the actual vehicle test, and the tire constituent member is destroyed when the physical property value of the tire constituent member becomes smaller than a certain physical property value (threshold) regardless of the input to the tire. .

  In addition, with respect to the physical properties of tire constituent members, the physical property values change with temperature changes, with some exceptions. Therefore, it is important to measure the physical property value when the tire constituent member is destroyed in the temperature range when the destruction occurs.

  The tire test condition setting method of the present invention has been made based on the above-described knowledge, and hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  In the tire test condition setting method of the present invention, as shown in FIG. 3, an actual vehicle test is performed until the tire breaks in a tire having the same configuration (the more the better) (step 1). From the tire destroyed at the same location (tire constituent member), the destroyed tire constituent member is sampled and its physical property value is measured (step 2). At that time, in order to avoid deterioration in physical properties due to factors other than the test conditions, it is preferable to sample and measure tire constituent members that have broken from the tire immediately after breaking.

  When measuring physical property values of sampled tire constituent members, the temperature range in which the tire constituent members are destroyed during running of the actual vehicle (for example, 100 ° C. ± 10 ° C. when broken at around 100 ° C.), preferably tires during running of the actual vehicle Measuring at the same temperature as the temperature at which the structural member broke (when the sampled tire structural member is heated to the temperature at which it broke during actual vehicle driving) is a physical property value under actual use conditions. Good. However, if the physical property value varies in proportion to the temperature, it may be a physical property value measured at room temperature (measured with the sampled tire constituent member at room temperature).

  As a physical property value of a tire constituent member, for example, when a belt layer is broken (belt edge separation occurs) in an actual vehicle test, a peel force between belt layers can be given as a physical property value of the belt layer. Further, when the carcass layer breaks (carcass cord breaks) in an actual vehicle test, the strength of the broken carcass cord can be cited as a physical property value.

  Next, the destruction threshold value of the tire constituent member is determined from the measured physical property values (step 3). For example, when the physical property values are obtained for a plurality of tires, the average can be used as the threshold value for destruction of the tire constituent members.

  Next, a lab test is performed on a tire having the same configuration as that of the actual vehicle test tire under preset conditions (step 4). For example, in the case of a tire in which a belt layer is broken (belt edge separation occurs) in an actual vehicle test, an indoor drum test is performed as a laboratory test. The indoor drum test can also be performed in the case of a tire in which the carcass layer is broken (carcass cord breakage) in the actual vehicle test.

  As a pre-set condition, when a belt layer destructive test is performed by an indoor drum test, for example, after the test tire is oxidatively deteriorated, a constant load is applied and the tire rotates while gradually increasing the drum rotation speed. Set the test to continue until destroyed.

  After the test is completed, it is confirmed whether or not the location where the tire is destroyed is the same tire component as in the actual vehicle test (step 5). If the same tire constituent member as that in the actual vehicle test does not break, the test is carried out by changing the setting conditions (step 6). The test is performed by changing the setting conditions until the same tire component as in the actual vehicle test is destroyed.

  When the same tire constituent member as that in the actual vehicle test is destroyed, the physical property value of the destroyed tire constituent member is measured (step 7). For example, when the belt layer is broken, the peeling force between the belt layers is measured as the physical property value of the belt layer. The measurement of the physical property value is performed under the same conditions as those for measuring the physical property value of the tire constituent member sampled in the actual vehicle test. That is, when the physical property value of the sampled tire constituent member is measured at one point (for example, 95 ° C.) in the temperature region where the tire constituent member is destroyed during actual vehicle travel, measurement is performed under the same condition (95 ° C.). Moreover, when the physical property value of the sampled tire constituent member is measured at the temperature when the tire constituent member is destroyed (for example, 100 ° C.), the tire constituent member destroyed in the laboratory test is measured under the same condition (100 ° C.). To do. Moreover, when the physical property value of the sampled tire constituent member is measured at room temperature, the measurement is similarly performed at room temperature.

  After measuring the physical property value of the destroyed tire component, it is determined whether or not the physical property value is at the same level as the threshold value (step 8). This step is to confirm that the tire subjected to the laboratory test is at the same level as the tire of the actual vehicle test. When the physical property value shows the same level as the threshold value, the above-described preset condition is set as a laboratory test condition of a test tire to be compared with the tire subjected to the actual vehicle test (Step 9). If the measured physical property value is not at the same level as the threshold value, the steps from step 4 are performed on another tire having the same configuration as the tire of the actual vehicle test.

  When a lab test is performed on a test tire under the lab test conditions obtained in this way, the tire component of the test tire (the same tire component as the actual tire tested) is destroyed before the lab test is completed. In this case, the test tire is inferior to the tire in the actual vehicle test (the tire in which the tire constituent member satisfies the predetermined level), that is, the tire performance (tire constituent member) in the actual vehicle test has not reached the predetermined level. It can be seen that it is. On the other hand, if the tire component of the test tire does not break even after the laboratory test is completed, the test tire is superior to the tire of the actual vehicle test, that is, the tire performance (tire configuration in the actual vehicle test). It can be seen that the member is a tire that has reached a predetermined level.

  Therefore, by adopting and testing the obtained laboratory test conditions, it is not a relative evaluation that simply compares tires, but a laboratory test to determine whether the tire performance (tire component) satisfies a predetermined level in the actual vehicle test. This makes it possible to make a reliable determination.

  In the present invention, the lab test of a tire is not a test (actual vehicle test) performed by actually mounting a tire on a vehicle, but a test performed by mounting a tire on a test apparatus. Such a laboratory test is not limited to the indoor drum test described above, and may be an outdoor test performed by attaching a tire to a test apparatus outdoors. The indoor drum test referred to here is, for example, a test performed using a drum test apparatus defined in JIS.

  In the above-described embodiment, the present invention has been described with respect to a method for setting test conditions for a lab test using a tire. However, the present invention is also applicable to a method for setting test conditions in a lab test performed using a tire constituent member itself (sample). It is possible.

  The tire referred to in the tire test condition setting method of the present invention may be any tire that can be tested, such as a pneumatic tire for passenger cars and a pneumatic tire for heavy loads.

The tire size is the same for 280 / 650R18, and the belt delamination force at room temperature and the fractured temperature range of tire A (the actual vehicle test was carried out after being stored in Japan for 2 years) where edge separation occurred in the belt layer by the actual vehicle test ( 100 degrees Celsius), and tire B stored for one year under high temperature and high humidity (stored in a warehouse in Thailand), tire C stored for one and a half years, and tire D stored for two years Table 1 shows the results of performing an indoor drum test under the conditions and measuring the belt delamination force at room temperature and in the destroyed temperature range (100 ° C.).
Indoor drum test Each test tire was set to an air pressure of 200 kPa and attached to an indoor drum tester. Under a load of 4 kPa and an ambient temperature of 25 ° C., the speed was rapidly increased from 0 to 200 km / h, and then 200 km / hr. Every 20 minutes from h, the speed is increased by 20 km to a maximum of 300 km / h.

  From Table 1, in the drum C of the indoor drum test, the belt delamination force (physical property value) measured in the fractured temperature region is at the same level as that of the tire A of the actual vehicle test. Therefore, in the belt edge separation test, The tire test conditions employed for the tire C can be set. On the other hand, the belt delamination force (physical property value) measured at room temperature cannot be used because it is not proportional to the belt delamination force measured in the destroyed temperature region. It turns out that it is good to use.

  The tire size is common to 235 / 45R17, and the carcass cord strength at the room temperature and the carcass cord strength in the destroyed temperature range (100 ° C) of the tire E in which the carcass cord breakage occurred in the actual vehicle test (circuit running), and the indoor drum Table 2 shows the results of measuring the carcass cord strength at the room temperature and the fractured temperature range (100 ° C.) of the tires F and G subjected to the fracture test (carcass cord fracture) by the test.

  From Table 2, the tire G in which the carcass cord breakage occurred in the indoor drum test showed that the carcass cord strength measured at room temperature and the carcass cord strength measured in the destroyed temperature range fluctuated substantially proportionally at room temperature. It can be seen that measured physical property values may be employed.

It is a graph which shows the relationship between the physical property of a tire structural member, and a log | history. It is a graph explaining the relationship between the physical property of a tire structural member, and an input. It is a flowchart which shows one Embodiment of the tire test condition setting method of this invention.

Claims (5)

  The threshold value of the destruction of the tire constituent member is determined from the physical property value of the destroyed tire constituent member sampled from the tire destroyed by the actual vehicle test, and the lab is set in advance for the tire having the same configuration as the tire of the actual vehicle test. When the test is performed and the tire of the laboratory test is broken in the same tire constituent member as the actual vehicle test, and the physical property value of the tire constituent member shows the same level as the threshold value, the preset condition is the tire The tire test condition setting method used as the laboratory test condition of the test tire to be compared with.   2. The tire test condition setting method according to claim 1, wherein the physical property value of the tire constituent member destroyed in the actual vehicle test and the laboratory test is a physical property value measured in a temperature region in which the tire constituent member is destroyed during actual vehicle travel.   The tire test condition setting method according to claim 2, wherein the physical property value of the tire constituent member destroyed in the actual vehicle test and the laboratory test is a physical property value measured at a temperature at which the tire constituent member is destroyed during actual vehicle travel.   The tire test condition setting method according to claim 1, wherein a physical property value of the tire constituent member destroyed in the actual vehicle test and the laboratory test is a physical property value measured at room temperature.   The tire test condition setting method according to claim 1, wherein the laboratory test is an indoor drum test.

Images