JP2006170694A - Tire endurance test method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire endurance test method which enables the accurate evaluation of durability while actually traveling for evaluating durability of pneumatic tires as they remain loaded with a load and a slip angle over a rotary drum. <P>SOLUTION: The pneumatic tires A and B loaded with a load and a slip angle are made to travel over the rotary drum D to detect lateral forces SF generated in the directions of rotational axes of the tires during their travel. As controlling the lateral forces SF at desired values, their traveling conditions are maintained. Alternatively, as controlling the products of the lateral forces SF and slip angles SA at desired values, their traveling conditions are maintained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a tire endurance test method using a drum type endurance test apparatus, and more specifically, in evaluating the durability of a pneumatic tire in a state where a load and a slip angle are given on a rotating drum, The present invention relates to a tire durability test method that makes it possible to more accurately evaluate durability.

  In a tire durability test method using a drum-type durability test apparatus, a slip angle is employed as an input parameter for running conditions. For example, when a slalom test is performed, the slip angle of a pneumatic tire continuously running on a rotating drum is periodically changed with a certain fluctuation range (see, for example, Patent Document 1).

  However, when durability is evaluated for a plurality of types of pneumatic tires under the same slip angle, the lateral force generated during running differs depending on the tire characteristics. For example, when the cornering power is different between tires, even if the slip angle is the same, a tire having a large cornering power has a greater lateral force in the tire rotation axis direction, which is disadvantageous in durability evaluation. On the other hand, in actual traveling, tires having any characteristics receive the same lateral force when traveling on the same course at the same speed. That is, when the durability is evaluated under the same slip angle, the lateral force applied to the tire differs depending on the tire characteristics, and there is a problem that the durability in actual running is not always accurately reflected.

In the tire durability test, the tire tread part gradually wears, and the cornering characteristics of the tire change with the wear, so the severity of the driving environment changes with time and has a significant effect on durability. Therefore, the temperature of the belt edge portion that gives rises to change. Therefore, there is a demand for a test method that gives a certain degree of severity from the beginning to the end of the tire durability test.
JP 2003-294585 A

  An object of the present invention is to evaluate a durability of a pneumatic tire in a state where a load and a slip angle are applied on a rotating drum, and a tire durability test that can more accurately evaluate durability in actual running. It is to provide a method.

  In order to achieve the above object, the first tire durability test method of the present invention is a method in which a pneumatic tire is caused to travel on a rotating drum with a load and a slip angle applied, and a lateral force generated in the tire rotation axis direction during traveling. Is detected, and the running state is maintained while controlling the lateral force to a desired value.

  Further, the second tire durability test method of the present invention for achieving the above object is to cause a pneumatic tire to travel on a rotating drum with a load and a slip angle applied, and to occur in the tire rotation axis direction during traveling. The lateral force is detected, and the running state is maintained while controlling the product of the lateral force and the slip angle to a desired value.

  In the first tire endurance test method of the present invention, the lateral force generated in the tire rotation axis direction during traveling is detected, and the traveling state is maintained while controlling the lateral force to a desired value. Durability can be evaluated under the conditions of equality (severity). Therefore, when evaluating the durability of a pneumatic tire in a state where a load and a slip angle are applied on the rotating drum, the durability in actual traveling can be more accurately evaluated.

  As one form of the first tire endurance test method, a pretreatment including a dry heat treatment for at least 24 hours is performed in a state where a pneumatic tire is filled with a gas having an oxygen concentration of 30% or more, and then the sealed gas of the pneumatic tire is filled. Is a tire endurance test method for carrying out a main run on a rotating drum by exchanging, and when the main run is carried out, the pneumatic tire is run on a rotating drum with a load and a slip angle applied thereto, There is provided a tire durability test method characterized by detecting a lateral force generated in a tire rotation axis direction and maintaining a running state while controlling the lateral force to a desired value.

  Further, as one form of the first tire durability test method, a pretreatment running on a rotating drum including continuous running for at least 24 hours in a state where a pneumatic tire is filled with a gas having an oxygen concentration of 30% or more is performed. Next, a tire endurance test method for carrying out the main running on the rotating drum by changing the sealed gas of the pneumatic tire, and when carrying out the main running, the load and slip angle of the pneumatic tire are adjusted on the rotating drum. There is provided a tire durability test method characterized in that the vehicle is run in a given state, a lateral force generated in the tire rotation axis direction during the running is detected, and the running state is maintained while the lateral force is controlled to a desired value. The

  Furthermore, as one form of the first tire durability test method, there is a tire durability test method for evaluating the remaining durability of a pneumatic tire after running on the market, wherein the pneumatic tire provided for running on the market is a rotating drum. The vehicle is run with a load and a slip angle applied thereto, detects lateral force generated in the tire rotation axis direction during running, and maintains the running state while controlling the lateral force to a desired value. A tire durability test method is provided.

  Furthermore, as one form of the first tire durability test method, a tire durability test method for evaluating the remaining durability of a pneumatic tire after running on the market, the tread surface of the pneumatic tire being used for running on the market After buffing, the pneumatic tire is run on a rotating drum with a load and a slip angle applied, and the lateral force generated in the tire rotation axis direction during running is detected, and the lateral force is set to a desired value. There is provided a tire durability test method characterized by maintaining a running state while being controlled.

  On the other hand, in the second tire durability test method of the present invention, the lateral force generated in the tire rotation axis direction during traveling is detected, and the traveling state is maintained while controlling the product of the lateral force and the slip angle to a desired value. By doing so, it is possible to evaluate the durability under the condition in which the severity of the traveling environment is made constant regardless of the wear of the tire tread portion. Thereby, when evaluating the durability of a pneumatic tire in a state where a load and a slip angle are applied on the rotating drum, it is possible to more accurately evaluate the durability in actual driving.

  As one form of the second tire durability test method, a pretreatment including a heat treatment for at least 24 hours is performed in a state where a pneumatic tire is filled with a gas having an oxygen concentration of 30% or more, and then the sealed gas of the pneumatic tire is filled. Is a tire endurance test method for carrying out a main run on a rotating drum by exchanging, and when the main run is carried out, the pneumatic tire is run on a rotating drum with a load and a slip angle applied thereto, There is provided a tire durability test method for detecting a lateral force generated in a tire rotation axis direction and maintaining a running state while controlling a product of the lateral force and a slip angle to a desired value.

  Further, as one form of the second tire durability test method, pretreatment running including continuous running for at least 24 hours in a state where a pneumatic tire is filled with a gas having an oxygen concentration of 30% or more is performed. Next, a tire endurance test method for carrying out the main running on the rotating drum by changing the sealed gas of the pneumatic tire, and when carrying out the main running, the load and slip angle of the pneumatic tire are adjusted on the rotating drum. A tire that travels in a given state, detects a lateral force generated in the tire rotation axis direction during traveling, and maintains a traveling state while controlling a product of the lateral force and a slip angle to a desired value. An endurance test method is provided.

  Furthermore, as one form of the second tire durability test method, there is a tire durability test method for evaluating the remaining durability of a pneumatic tire after running on the market, wherein the pneumatic tire provided for running on the market is a rotating drum. Running with the load and slip angle applied above, detect the lateral force generated in the direction of the tire rotation axis during running, and maintain the running state while controlling the product of the lateral force and slip angle to the desired value A tire durability test method is provided.

  Furthermore, as one form of the second tire durability test method, there is a tire durability test method for evaluating the remaining durability of a pneumatic tire after running on the market, the tread surface of the pneumatic tire being used for running on the market After the buff treatment, the pneumatic tire is caused to travel on the rotating drum with a load and a slip angle applied thereto, and a lateral force generated in the tire rotation axis direction during the traveling is detected, and the lateral force and the slip angle are detected. There is provided a tire durability test method characterized by maintaining a running state while controlling a product to a desired value.

  The inventor has found that the product of the lateral force and the slip angle is proportional to the temperature in the vicinity of the belt edge of the tire tread portion during traveling. Therefore, the tire internal temperature can be controlled within a desired range (± 3 ° C.) based on the product of the lateral force and the slip angle. That is, according to the present invention, a pneumatic tire is caused to travel on a rotating drum with a load and a slip angle applied thereto, a lateral force generated in the tire rotation axis direction during traveling is detected, and the lateral force and the slip angle are detected. A tire durability test method is provided that maintains the running state while controlling the tire internal temperature within a desired range based on the product of

  In the present invention, the evaluation items of the durability test performed while maintaining the running state of the pneumatic tire are not particularly limited, the running distance until the tire breaks, the running distance until a failure such as separation occurs, and the wear The characteristic etc. can be mentioned.

  In the tire durability test method of the present invention, a drum-type durability test apparatus is used. This drum type durability test apparatus includes a drum for rolling a pneumatic tire, a driving means for rotating the drum, and a support means for rotatably supporting the pneumatic tire under conditions of a predetermined load and a slip angle. And those known in the tire industry can be used. The diameter of the drum may be in the range of 1500 to 2000 mm, for example, and is generally 1707 mm.

  In the first tire durability test method, a pneumatic tire is run on a rotating drum with a load and a slip angle applied thereto, and a lateral force generated in the tire rotation axis direction during running is detected using a load cell or the like, The running state is maintained while controlling the lateral force to a desired value. Controlling the lateral force to a desired value means guiding the lateral force to a preset value. As a method of controlling the lateral force, there are a method of changing a slip angle, a method of changing an air pressure, a method of changing a load, a method of changing a speed, and the like, but these may be combined.

  Here, consider a tire A having a relatively high cornering power and a tire B having a relatively low cornering power. As shown in FIG. 1, in the slalom test in which the slip angle SA (amplitude) is periodically changed, when the slip angles SA of the tires A and B running on the rotary drum D are the same, the tire rotation axis during running The lateral force SF (amplitude) generated in the direction is larger in the tire A than in the tire B. That is, the tire A is exposed to a severer driving environment. On the other hand, as shown in FIG. 2, in the slalom test in which the slip angle SA is periodically changed, the slip angle SA of the tires A and B traveling on the rotary drum D is optimized, and the tire rotation shaft is rotated during the travel. When the lateral force SF generated in the direction is the same, the durability can be evaluated under the condition that the harshness of the traveling environment is made equal.

  By adopting lateral force as an input parameter for driving conditions as described above, it is possible to evaluate durability under the conditions where the harshness of the driving environment is equivalent, and as a result, durability in actual driving is further improved. Accurate evaluation is possible.

  On the other hand, in the second tire endurance test method, a pneumatic tire is run on a rotating drum with a load and a slip angle applied, and a lateral force generated in the tire rotating axis direction during running is detected using a load cell or the like. The running state is maintained while controlling the product of the lateral force and the slip angle to a desired value. Controlling the product of the lateral force and the slip angle to a desired value is to lead the product of the lateral force and the slip angle to a preset value. As a method of controlling the product of the lateral force and the slip angle, there are a method of changing the slip angle, a method of changing the air pressure, a method of changing the load, a method of changing the speed, etc., but these may be combined. .

  Here, in the slalom test, FIG. 3 shows changes with time of the lateral force SF (amplitude) when the slip angle SA (amplitude) is constant, and the slip angle when the lateral force SF (amplitude) is constant. The change with time of SA (amplitude) is shown in FIG. As can be seen from FIG. 3, when the slip angle SA is made constant, the cornering power increases with wear of the tire tread portion, so the lateral force SF gradually increases. For this reason, the severity of the driving environment increases with time. On the other hand, as can be seen from FIG. 4, when the lateral force SF is made constant, the cornering power increases with wear of the tire tread portion, so the slip angle SA gradually decreases. Therefore, the severity of the driving environment decreases with time.

  On the other hand, in the slalom test, when the slip angle SA is constant, the lateral force SF is constant, and the product of the slip angle SA and the lateral force SF is constant, the product of the slip angle SA and the lateral force SF, respectively. FIG. 5 shows the change over time. As shown in FIG. 5, when the product of the slip angle SA and the lateral force SF is made constant, the energy given to the tire tread is constant regardless of the wear of the tire tread, and the severity of the driving environment is tested. It remains constant from the beginning to the end.

  By adopting the product of lateral force and slip angle as an input parameter for driving conditions as described above, it is possible to evaluate the durability under the condition that the severity of the driving environment is constant. It is possible to more accurately evaluate the durability.

  6 shows the relationship between the slip angle SA (amplitude) and the belt edge temperature in the slalom test, and FIG. 7 shows the product of the lateral force SF (amplitude) and the slip angle SA (amplitude) in the slalom test and the belt edge temperature. It shows the relationship. FIG. 6 and FIG. 7 show the results when the air pressure is set to 700 kPa and 850 kPa for the tire of tire size 11R22.5. As can be seen from FIGS. 6 and 7, a linear proportional relationship is recognized between the product of the lateral force SF and the slip angle SA and the belt edge temperature.

  That is, when the product of the lateral force SF and the slip angle SA is adopted as an input parameter of the running condition and the product of the lateral force SF and the slip angle SA is made constant, the belt edge temperature is set within a desired range (± 3 ° C. ) Can be controlled. This makes it possible to evaluate the durability of the pneumatic tire while keeping the belt edge temperature that greatly affects the durability constant.

  In the tire durability test method, a pretreatment including a dry heat treatment for at least 24 hours is performed in a state in which a pneumatic tire is filled with a gas having an oxygen concentration of 30% or more, and then a sealed drum of the pneumatic tire is replaced with a rotating drum. This is effective when carrying out the above main driving. That is, when carrying out the main running, the pneumatic tire is run with a load and a slip angle on the rotating drum, and the lateral force generated in the tire rotation axis direction during running is detected. The running state is maintained while controlling the product of the slip angle and the desired value.

  In the pre-treatment, performing dry heat treatment for at least 24 hours in a state where the pneumatic tire is filled with a gas having an oxygen concentration of 30% or more promotes oxidative degradation, and in the actual running, the durability in actual running is further increased. This is for accurate evaluation. The oxygen concentration referred to here is a volume fraction, and can be obtained from, for example, the partial pressure of oxygen with respect to the total pressure of gas. If the oxygen concentration in the pretreatment is less than 30%, the promotion of oxidative deterioration becomes insufficient. Further, if the dry heat treatment in the pretreatment is less than 24 hours, the oxidation deterioration is not sufficiently promoted. The upper limit of the dry heat treatment time is desirably 480 hours.

  In the tire durability test method, pretreatment running is performed on a rotating drum including continuous running for at least 24 hours in a state where a pneumatic tire is filled with a gas having an oxygen concentration of 30% or more, and then the pneumatic tire is used. It is effective when carrying out the main running on the rotating drum by replacing the enclosed gas. That is, when carrying out the main running, the pneumatic tire is run with a load and a slip angle on the rotating drum, and the lateral force generated in the tire rotation axis direction during running is detected. The running state is maintained while controlling the product of the slip angle and the desired value.

  In pre-treatment running, continuous running for at least 24 hours in a state where the pneumatic tire is filled with a gas having an oxygen concentration of 30% or more causes the pneumatic tire to generate heat according to its inherent heat generation characteristics and approximates actual running This is to promote oxidation deterioration and outer diameter growth in the generated heat state, and to more accurately evaluate the durability in actual traveling in the actual traveling. The oxygen concentration referred to here is a volume fraction, and can be obtained from, for example, the partial pressure of oxygen with respect to the total pressure of gas. If the oxygen concentration in the pretreatment traveling is less than 30%, the promotion of oxidation deterioration becomes insufficient. Further, when the continuous running in the pretreatment running is less than 24 hours, the oxidation deterioration and the promotion of the outer diameter growth are insufficient. The continuous running time in the pretreatment running can be arbitrarily set according to the load on the tire and the running speed of the tire, but the upper limit is desirably 480 hours.

  Furthermore, the tire durability test method is effective in evaluating the remaining durability of a pneumatic tire after running on the market. That is, a pneumatic tire subjected to market driving is run on a rotating drum with a load and a slip angle applied, and a lateral force generated in the tire rotation axis direction during running is detected. The running state is maintained while controlling the product of the slip angle to a desired value. You may buff the tread surface of the pneumatic tire used for market driving | running | working, and you may use for a running test. In this case, it eliminates the causes of uneven wear such as heel and toe wear, center wear, shoulder wear, polygonal wear, etc. that occur in pneumatic tires that have been put on the market, and more accurately maintains the remaining durability related to the tire structure. Can be evaluated.

  Two types of pneumatic tires A and B having a tire size of 11R22.5 and having the same evaluation from the market for durability are prepared. The cornering characteristics of these tires A and B are as shown in FIG. That is, the tire A has a relatively high cornering power, and the tire B has a relatively low cornering power. For these tires A and B, two types of tire durability tests (slalom tests) were performed. In one tire durability test (conventional example), the running state was maintained while controlling the slip angle SA (amplitude) to about ± 2.5 °, and the running distance until the tire broke was measured. In the other tire endurance test (Example), the lateral force SF generated in the tire rotation axis direction during running is detected, the running state is maintained while the lateral force SF is controlled to about 5.61 kN, and the tire is destroyed. The distance traveled was measured. In either case, the load was 32.08 kN and the speed was 45 km / h. The traveling distance measured in these tire durability tests is shown in FIG.

  As can be seen from FIG. 9, according to the tire durability test method of the example, the evaluation in the market is more accurately reflected on the two types of pneumatic tires A and B that have obtained the same durability evaluation in the market. I was able to get the results.

In a slalom test, it is a side view which shows the case where the slip angle SA of the tire which drive | works on a rotating drum is made the same. In a slalom test, it is a side view which shows the case where the slip angle SA of the tire which drive | works on a rotating drum is optimized, and the lateral force SF which arises in a tire rotating shaft direction during driving | running | working is made the same. It is a graph which shows the time-dependent change of lateral force SF when slip angle SA is made constant in the slalom test. It is a graph which shows the time-dependent change of slip angle SA when lateral force SF is made constant in a slalom test. In the slalom test, when the slip angle SA is constant, the lateral force SF is constant, and the product of the slip angle SA and the lateral force SF is constant, the product of the slip angle SA and the lateral force SF is elapsed over time. It is a graph which shows a typical change. It is a graph which shows the relationship between the slip angle SA and belt edge temperature in a slalom test. It is a graph which shows the relationship between the product of lateral force SF and slip angle SA, and belt edge temperature in a slalom test. 4 is a graph showing cornering characteristics of test tires A and B. It is a graph which shows the travel distance in the tire endurance test of test tires A and B.

Explanation of symbols

A, B Tire D Rotating drum SA Slip angle SF Lateral force

Claims (11)

Running a pneumatic tire on a rotating drum with a load and slip angle applied, detecting lateral force generated in the direction of the tire rotation axis during traveling, and maintaining the traveling state while controlling the lateral force to a desired value A tire durability test method characterized by: Pretreatment including dry heat treatment for at least 24 hours in a state where the pneumatic tire is filled with a gas having an oxygen concentration of 30% or more is performed, and then the main gas is run on the rotating drum by replacing the filled gas of the pneumatic tire. A tire endurance test method for detecting the lateral force generated in the direction of the tire rotation axis during travel by running a pneumatic tire on a rotating drum with a load and a slip angle applied when performing the main travel. And maintaining the running state while controlling the lateral force to a desired value. Pretreatment running on a rotating drum including continuous running for at least 24 hours in a state where a pneumatic tire is filled with a gas having an oxygen concentration of 30% or more is carried out. The tire endurance test method for carrying out the main running at the time of carrying out the main running in which the pneumatic tire is run with a load and a slip angle on the rotating drum, and the tire rotating axis direction during running A tire endurance test method comprising: detecting a lateral force generated in the vehicle and maintaining a running state while controlling the lateral force to a desired value. A tire durability test method for evaluating the remaining durability of a pneumatic tire after running on the market, and running the pneumatic tire provided for running on the market with a load and a slip angle on a rotating drum, A tire endurance test method characterized by detecting a lateral force generated in the tire rotation axis direction during traveling and maintaining the traveling state while controlling the lateral force to a desired value. A tire durability test method for evaluating the remaining durability of a pneumatic tire after running on the market, wherein after the tread surface of the pneumatic tire subjected to market running is buffed, the pneumatic tire is placed on a rotating drum. The tire is caused to travel with a load and a slip angle applied thereto, detects lateral force generated in the tire rotation axis direction during traveling, and maintains the traveling state while controlling the lateral force to a desired value. Endurance test method. A pneumatic tire is run on a rotating drum with a load and slip angle applied, and the lateral force generated in the tire rotation axis direction is detected during running, and the product of the lateral force and slip angle is controlled to a desired value. A tire durability test method characterized by maintaining a running state while driving. A pretreatment including a heat treatment for at least 24 hours is performed in a state where the pneumatic tire is filled with a gas having an oxygen concentration of 30% or more, and then the main running on the rotating drum is performed by replacing the filled gas of the pneumatic tire. A tire endurance test method for detecting the lateral force generated in the direction of the tire rotation axis during travel by running a pneumatic tire on a rotating drum with a load and a slip angle applied when performing the main travel. And maintaining the running state while controlling the product of the lateral force and the slip angle to a desired value. Pretreatment running on a rotating drum including continuous running for at least 24 hours in a state where a pneumatic tire is filled with a gas having an oxygen concentration of 30% or more is carried out. The tire endurance test method for carrying out the main running at the time of carrying out the main running in which the pneumatic tire is run with a load and a slip angle on the rotating drum, and the tire rotating axis direction during running A tire endurance test method characterized by detecting a lateral force generated in the vehicle and maintaining a running state while controlling a product of the lateral force and a slip angle to a desired value. A tire durability test method for evaluating the remaining durability of a pneumatic tire after running on the market, and running the pneumatic tire provided for running on the market with a load and a slip angle on a rotating drum, A tire durability test method characterized by detecting a lateral force generated in the tire rotation axis direction during traveling and maintaining the traveling state while controlling a product of the lateral force and the slip angle to a desired value. A tire durability test method for evaluating the remaining durability of a pneumatic tire after running on the market, wherein after the tread surface of the pneumatic tire subjected to market running is buffed, the pneumatic tire is placed on a rotating drum. The vehicle is run with a load and a slip angle applied, and the lateral force generated in the tire rotation axis direction is detected during running, and the running state is maintained while controlling the product of the lateral force and the slip angle to a desired value. A tire durability test method characterized by the above. A pneumatic tire is run on a rotating drum with a load and a slip angle applied, and a lateral force generated in the tire rotation axis direction is detected during running, and the tire internal temperature is determined based on the product of the lateral force and the slip angle. A tire durability test method characterized in that the running state is maintained while controlling the pressure within a desired range.

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