JP2013113724A - Tire wear prediction method and tire wear prediction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire wear prediction method and tire wear prediction device capable of predicting a wear amount of a tire used for an aircraft with high accuracy.SOLUTION: The tire wear prediction method predicts the wear amount of a tire used in an aircraft. The tire wear prediction method includes a step A for acquiring a plurality of wear energies En corresponding to each of a plurality of traveling states divided in accordance with use conditions, a step B for multiplying the plurality of wear energies En by each use frequency of the plurality of traveling states in each of the plurality of traveling states, and calculating the entire wear energy EA accumulated in a tire by integrating multiplication results, and a step C for calculating the wear amount of the tire for the aircraft on the basis of the entire wear energy EA.

Description

  The present invention relates to a tire wear prediction method and a tire wear prediction apparatus for predicting the wear amount of a tire, particularly a tire used in an aircraft.

  In the development of pneumatic tires, with the development of numerical analysis methods and computer environments, tires such as the wear of newly designed pneumatic tires even without actually producing pneumatic tires and mounting them on automobiles for running tests Performance prediction / evaluation has become possible (for example, see Patent Document 1).

  Patent Document 1 discloses a method for predicting tire wear using a measuring device that measures a longitudinal stress (shearing force) and a slip amount using a strain gauge as a wear prediction method for passenger car tires. Yes. Specifically, in the method according to Patent Document 1, the stress (shearing force) in the front-rear direction for each running state, such as during steady running (free rolling) of a tire, during turning, during acceleration, and during deceleration. ) And slip amount. Since the friction energy is calculated by multiplying the shearing force and the slip amount, a predicted value of the friction energy in each traveling state is calculated based on the measurement result. Further, in this method, the correction coefficient is calculated based on the calculated predicted value of each frictional energy and the actually measured value acquired by actual traveling of the vehicle. In this method, the predicted value of friction energy is corrected based on the correction coefficient, and the total accuracy of each corrected friction energy is used for prediction of the amount of tire wear, thereby improving the prediction accuracy. A method described in Japanese Patent No. 4198610 has also been proposed for the purpose of collecting data with higher accuracy.

  By using such a tire wear prediction method, the development period of a pneumatic tire can be shortened by replacing a part of the development cycle such as design, manufacture, and evaluation of the pneumatic tire with numerical analysis.

JP 2001-001723 A Japanese Patent No. 4198610

  By the way, tires used for aircraft are used on the runway surface of an airport depending on a running state such as landing, pushback running, taxi running, and the like. In particular, at the time of landing, rapid acceleration and slipping of the tire occur.

  In the method according to the prior art, it is difficult to obtain a predicted value of wear energy according to the running state of tires used in such an aircraft, particularly the running state at the time of landing, with high accuracy. Therefore, it is difficult to predict the wear amount with high accuracy for tires used in aircraft, and countermeasures have been desired.

  Accordingly, the present invention has been made in view of the above-described problems, and provides a tire wear prediction method and a tire wear prediction apparatus capable of predicting the wear amount of a tire used in an aircraft with high accuracy. Objective.

  In order to solve the above-described problems, the inventors first examined a method for predicting wear energy that should be distinguished for each traveling state of a tire in order to predict wear of a tire used in an aircraft. As a result, the inventors have discovered that the wear energy prediction method should be distinguished for each of a plurality of running states including, for example, touchdown.

  Based on this knowledge, the present invention has the following features. In other words, a first feature of the present invention is a tire wear prediction method for predicting the wear of aircraft tires, wherein a plurality of wear energies En corresponding to each of a plurality of travel states divided according to use conditions are obtained. Step A (step S120) to be acquired, the plurality of wear energies En, and the frequency of use of each of the plurality of travel states are multiplied for each of the plurality of travel states, and the multiplication results are accumulated and accumulated in the tire. Including a step B (step S130) for calculating the total wear energy EA and a step C (step S140) for calculating the wear amount of the aircraft tire based on the total wear energy EA. It is.

  In the tire wear prediction method according to the first aspect of the present invention, the plurality of wear energies En and the use frequencies of the plurality of running states are multiplied by the plurality of running states, and the multiplication results are integrated. The total wear energy EA accumulated in the tire is calculated, and the tire wear amount is predicted based on the total wear energy EA.

  As described above, according to the tire wear prediction method, the tire wear is predicted by distinguishing a plurality of traveling states such as at the time of touchdown, and therefore, the wear amount of the tire can be predicted with higher accuracy than in the case where the tire wear is not distinguished. . Thus, according to the tire wear prediction method, the amount of wear of a tire used in an aircraft can be predicted with high accuracy.

  The second feature of the present invention is related to the above feature, wherein the plurality of running states are a touch-down running showing a running state from a time T1 when the aircraft tire has landed to a time T2 at which the tire rotation speed reaches a peak. The aircraft tires in the period from the time point T2 to the time point T3 after the first braking state is completed, the decelerating driving state after touchdown, and the period from the time point T3 to the next takeoff. Including a taxi traveling state indicating a traveling state in which the aircraft travels and a pushback traveling state indicating a traveling state in which the aircraft is pulled by a special vehicle, and the taxi traveling state includes an external force applied to the aircraft tire. By rolling without working, a braking force is applied to the aircraft tire and a free-rolling traveling state indicating a traveling state in which the aircraft travels straight ahead. A deceleration state indicating the traveling state of the traveling Te, and summarized in that includes a turning state indicating the traveling state where the aircraft tire travels to pivot.

  According to a third aspect of the present invention, the step A includes the wear energy E1 per landing in the touchdown running state and the reduced running state after the touchdown as the plurality of wear energies. Wear energy E2 per unit travel distance, wear energy E3 per unit travel distance in the free rolling travel state, wear energy E4 per unit travel distance in the decelerating travel state, and unit travel distance in the turning travel state A wear energy E5 per unit travel distance and a wear energy E6 per unit travel distance in the pushback travel state, and in the step B, the use frequency corresponding to each of the plurality of travel states is used as the touch frequency. Number of times TD in the down running state and the running distance in the reduced running state after the touch down 1, a travel distance L2 in the free rolling travel state, a travel distance L3 in the decelerating travel state, a travel distance L4 in the turning travel state, and a travel distance L5 in the pushback travel state; The present invention includes a step of calculating the total wear energy EA using a formula of EA = E1 × TD + E2 × L1 + E3 × L2 + E4 × L3 + E5 × L4 + E6 × L5.

According to a fourth aspect of the present invention, the aircraft tire includes a plurality of rib rows, and the step B calculates the total wear energy EAn for each rib row. And

  A fifth feature of the present invention is that, in the step A, in the touch-down running state indicating the running state from the time point T1 when the aircraft tire has landed to the time point T2 when the tire rotation speed reaches a peak, The step of acquiring the wear energy E1 of the rib row includes the step of acquiring the wear energy E1 by reproducing the touch-down running state using a testing machine, thereby obtaining a period from the time point T1 to the time point T2. In a plurality of minute sections divided along the time axis, obtaining a first tangential force applied to the entire tread surface of the tire tread surface in each minute section, and proportional to the contact area of each rib row in each minute section And, by distributing the first tangential force, obtaining a second tangential force of each rib row in each minute section; By calculating the wear energy of each rib row in each minute section using the second tangential force as a shearing force, and integrating the wear energy for each rib row in each minute section, the touchdown running state And acquiring the wear energy E1 of each rib row per one landing.

  The sixth feature of the present invention is that, in the step C, a step of obtaining a wear resistance index Gl, a step of multiplying the overall wear energy E by the wear resistance index Gl, and calculating a predicted value of wear amount; It is made to include.

  A seventh feature of the present invention is a tire wear prediction apparatus, which is summarized in that the tire wear prediction method described above is executed.

  ADVANTAGE OF THE INVENTION According to this invention, the tire wear prediction method and tire wear prediction apparatus which can estimate the wear of the tire used for an aircraft with high precision can be provided.

FIG. 1 is a flowchart for explaining processing related to a tire wear prediction method according to the present embodiment. FIG. 2 is a flowchart for explaining processing for acquiring wear energy E1 to E6 for each traveling state according to the present embodiment. FIG. 3 is a flowchart illustrating a process for acquiring the wear energy E1 according to the present embodiment. FIG. 4 is a graph showing various measurement results measured using the measurement apparatus according to the present embodiment. FIG. 5 is a partial development view when the tread portion of the pneumatic tire according to the present embodiment is viewed in plan. FIG. 6 is a flowchart illustrating a process for acquiring the total wear energy EA according to the present embodiment. FIG. 7 is a flowchart for explaining processing for calculating a predicted tire wear amount according to the present embodiment. FIG. 8 is a configuration diagram of a tire wear prediction apparatus that executes the tire wear prediction method according to the present embodiment. 9, with respect to the sample tire 1 according to the embodiment, is a graph showing the calculation results of the wear energy E _n calculated on the basis of the tire wear prediction method according to the present invention. 10, to the sample tire 2 according to the embodiment was calculated based on the tire wear prediction method according to the present invention, is a graph showing the calculation results of the wear energy E _n. FIG. 11 is a graph illustrating the evaluation results according to the example.

  Embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings is contained.

[First Embodiment]
First, a first embodiment of a tire wear prediction method according to the present invention will be described. Specifically, (1) tire wear prediction method, (2) tire wear prediction device, and (3) actions and effects will be described.

(1) Tire Wear Prediction Method The tire wear prediction apparatus according to this embodiment calculates a tire wear prediction value by a tire wear prediction method. Specifically, the tire wear prediction device calculates a predicted value of the amount of wear of a tire based on frictional energy in a tread portion of a pneumatic tire (hereinafter also simply referred to as a tire). In the present embodiment, the tire to be predicted is an aircraft tire used for an aircraft, and is assumed to be used when landing, pushback traveling, and taxi traveling on an airport runway. . The tire also includes one or more circumferential grooves extending in the tire circumferential direction and a plurality of rib rows formed by being partitioned by the circumferential grooves in the tread portion. A tire wear prediction method for predicting tire wear will be described below.

(1.1) Outline of Tire Wear Prediction Method An outline of a tire wear prediction method according to the present embodiment will be described with reference to FIG. FIG. 1 is a flowchart for explaining processing by the tire wear prediction method according to the present embodiment.

  In step S120, the tire wear prediction device acquires a plurality of wear energies En corresponding to each of a plurality of travel states classified according to the use conditions of the aircraft tire. The wear energy En is the friction energy per unit area, and the unit is kgf / cm (N / m in the SI unit system).

  Here, in the present embodiment, the plurality of traveling states classified according to the use conditions of the aircraft tire include a touchdown traveling state, a post-touchdown deceleration traveling state, a taxi traveling state, and a pushback traveling state. Is included.

  The touchdown traveling state indicates a traveling state from time T1 when the aircraft tire landed to time T2 when the tire rotation speed reaches a peak.

  The decelerating travel state after touchdown indicates the travel state of the aircraft tire from the time point T2 to the time point T3 when the first braking state ends.

  The taxi traveling state indicates a traveling state in which an external force is not applied to the aircraft during a period from time T3 when the first braking state ends to the next takeoff. Further, the taxi traveling state includes a free rolling traveling state, a decelerating traveling state, and a turning traveling state.

  The free rolling traveling state indicates a traveling state in which the aircraft travels straight by rolling without external force acting on the aircraft tire. The decelerating running state indicates a running state in which a braking force is applied to the aircraft tire. The turning traveling state indicates a traveling state in which the aircraft tire travels while turning.

  The pushback traveling state indicates a traveling state in which the aircraft travels while being pulled by a special vehicle. Details of the process in step S120 will be described later.

  In step S130, the tire wear prediction apparatus multiplies the plurality of wear energies En and the usage frequencies of the plurality of travel states for each of the plurality of travel states, accumulates the multiplication results, and accumulates them in the aircraft tire. The total wear energy EA is calculated.

  Here, in the present embodiment, the usage frequency corresponding to each of the plurality of travel states is the number TD of the touchdown travel state, the travel distance L1 in the post-touchdown deceleration travel state, the travel distance L2 in the free rolling travel state, and the deceleration. It includes a travel distance L3 in the travel state, a travel distance L4 in the turning travel state, and a travel distance L5 in the pushback travel state. Details of the process in step S130 will be described later.

  In step S140, the tire wear prediction device predicts the amount of tire wear based on the total wear energy EA. Specifically, a predicted wear amount for the entire tire is calculated based on the total wear energy EA. Details of the process in step S140 will be described later.

(1.2) Method for Acquiring Wear Energy Corresponding to Running State Next, referring to FIG. 2, a process of obtaining a plurality of wear energies En corresponding to each of a plurality of running states in step S120 described above. Details will be described. FIG. 2 is a flowchart illustrating a process for acquiring a plurality of wear energies En according to the present embodiment.

  In step S121, the tire wear prediction device acquires wear energy E1 in the touchdown running state. The wear energy E1 is acquired by using a measuring device that can reproduce the touch-down running state. Details of step S121 will be described later.

  In step S122, the tire wear prediction device acquires wear energy E2 per unit travel distance in the decelerated travel state after touchdown. The post-touchdown deceleration running state refers to a running state in which braking force is generated between the road surface and the tire by applying braking torque to the wheels after touchdown.

  For example, the tire wear prediction device acquires the wear energy E2 per unit travel distance when the vehicle is decelerated while applying a braking force from a state where the tire speed is high (for example, 310 km / h).

Here, the wear energy per unit mileage is obtained by using the on-table wear energy measuring device described in Japanese Patent Laid-Open No. 2001-001723, or the tire tread surface described in Japanese Patent Laid-Open No. 7-63658. It can be obtained using a part measuring device. Taking the method disclosed in Japanese Patent Laid-Open No. 7-63658 as an example, the slip amount S (cm) is measured using a ground contact measuring device, and the shear force is measured using a three-component force transducer provided on the road surface. τ (kgf / cm 2) can be measured. As described in JP-A-7-63658, the frictional work amount e of the tire tread can be calculated by the following formula.

  Therefore, the frictional work amount of the tire tread can be calculated by the above formula using the slip amount S and the shearing force τ measured by the ground contact measuring device 10, and the frictional work amount e can be used as wear energy. As a method for measuring the slip amount S and the shearing force τ, a method disclosed in JP-A-7-63658 can be used.

  The tire wear prediction device acquires wear energy E2 measured using such a measuring device.

  In step S123, the tire wear prediction device acquires wear energy E3 per unit travel distance of a tire that is in a free rolling travel state during taxi travel. Here, the free rolling traveling state during taxi traveling refers to a state in which no external force is applied to the tire and the vehicle is simply rolling.

  The wear energy E3 can be measured using, for example, the method described in JP-A-2001-001723. Specifically, the tire is made to be rotatable, the tire is grounded by applying a load substantially equal to the load when the aircraft is mounted on the grounding table, and the tire grounding table is moved horizontally to roll the tire. Can be measured.

  In step S124, the tire wear prediction device acquires wear energy E4 per unit travel distance of a tire that is in a decelerating travel state during taxi travel. Here, the decelerating traveling state during taxi traveling refers to a traveling state in which braking force is generated between the road surface and the tire by applying braking torque to the axle for speed adjustment.

  For example, the tire wear prediction device acquires the wear energy E4 when the vehicle is decelerated by applying a braking force from a low tire speed (for example, 30 km / h). The difference in the measurement method from the wear energy E2 is only that the speed is low, and the measurement can be performed by the same method as the measurement method.

  In step S125, the tire wear prediction device acquires wear energy E5 per unit travel distance of a tire that is in a turning travel state during taxi travel. Here, the turning traveling at the time of taxi traveling refers to a state in which a lateral input is generated in the tire by bending the aircraft between the terminal and the take-off and landing road.

  The wear energy E5 is tire wear energy that is generated when the tire is traveling in a turning state, that is, when the tire is traveling with a slip angle given to the traveling direction of the aircraft. The wear energy E5 in such a turning state can also be measured using the method disclosed in Japanese Patent Laid-Open No. 7-63658.

  In step S126, the tire wear prediction device acquires wear energy E6 per unit travel distance of the tire that is in the pushback travel state. Here, the push-back running is a state in which a larger slip angle is given to the tire than when the vehicle turns in a normal manner when the machine body is taken out of the hangar. The wear energy E6 when such an aircraft is in a pushback traveling state can also be measured using the method disclosed in Japanese Patent Laid-Open No. 7-63658.

(1.3) Method for Acquiring Wear Energy in Touchdown Running State Next, with reference to FIG. 3, details of the process for obtaining the tire wear energy E1 in the touchdown running state in step S121 described above will be described. . FIG. 3 is a flowchart illustrating a process for acquiring the wear energy E1 according to the present embodiment.

  First, in step S1211, the tire wear prediction device determines, based on the measurement result by the device capable of reproducing the tire in the touch-down running state, the speed information indicating the temporal change in the tire speed at the time of touch-down and the tire at the time of the touch-down. The load information indicating the change with time of the load and the slip ratio information indicating the change with time of the slip ratio at the time of touchdown are acquired.

  Specifically, using a drum-type maneuverability tester as a measuring device, a test is performed to give the tire the same conditions as when the aircraft landed, and speed information, load information, and slip rate information are acquired. . The drum type maneuverability tester as the measuring device may be any drum tester as long as it has a performance capable of withstanding the load and speed of the aircraft tire.

  As a measuring method, a non-rotating tire is pressed at a constant speed against a drum rotating at a peripheral speed equivalent to that at landing until a specified load is generated in a shaft-free state. The pressing speed is equal to the speed at which the tire is pressed against the road surface during actual landing.

The speed information is information indicating a temporal change in the surface speed of the tire traveling on the drum. The load information is information indicating a change over time in the load applied to the tire traveling on the drum. The slip ratio information is information indicating a change over time of the slip ratio S expressed by the following equation 1 where the rolling radius of the tire is r, the rotational angular speed ω, and the drum peripheral speed V.

  Here, FIG. 4 is a graph showing various measurement results measured by the above-described test using the measuring apparatus. In the figure, the horizontal axis indicates the elapsed time (sec) when the tire T1 contacts the drum surface and the time T1 is “0”, and the vertical axis indicates the unit of each measured value. As shown in the figure, the measuring device can measure tire speed, drum speed, tire load, surface temperature, tangential force, and the like. Further, as shown in the figure, in this embodiment, the touchdown time Ttd is a period from the time T1 when the tire touches down at the time of landing to the time T2 when the tire speed reaches a peak.

  The tire wear prediction device can acquire various types of information shown in the figure by performing measurement using the measurement device. These pieces of information are information that can be measured by a conventionally used drum-type maneuverability tester.

  In step S1212, the tire wear prediction apparatus acquires a tire friction coefficient. Specifically, the tire wear prediction apparatus acquires a tire dynamic friction coefficient μ.

  In step S1213, the tire wear prediction device is applied to the entire tread surface of the tire tread surface in each minute section in a plurality of minute sections obtained by dividing the period from time T1 to time T2 when the tire contacts the ground along the time axis. Obtain a first tangential force. Specifically, the tire wear prediction device divides Ttd at the time of touchdown into minute intervals dt. The accuracy is improved as the minute interval dt is smaller, but sufficient accuracy is sufficient if it is a period of 1/5 or less of the period from the time T1 when the tire contacts the drum to the time T2 when the acceleration becomes “0”. It can be secured.

  Further, the tire wear prediction device extracts a tire load value Wdt for each minute section dt from the load information. At this time, when there are a plurality of data of tire load values corresponding to the minute section dt, the tire wear prediction device obtains one tire load value Wdt by calculating an average value.

Further, the tire wear prediction device calculates a first tangential force Fdt applied to the tire in the minute section dt based on the following one equation. In the following formula, μ represents a dynamic friction coefficient of the tire.

  In the above equation, when calculating the first tangential force, the dynamic friction coefficient μ is acquired instead of the static friction coefficient for the following reason. That is, when the tire contacts the ground contact surface of the drum, it instantaneously shifts from the static friction region to the dynamic friction region.

  In step S1214, the tire wear prediction device distributes the first tangential force Fdt in proportion to the ground contact area of each rib row in each minute section dt, whereby the second tangential force Fndt of each rib row in each minute section. To get.

Here, FIG. 5 shows a partial development view when the tread portion of the pneumatic tire according to the present embodiment is viewed in plan view.

  As shown in FIG. 5, eight circumferential grooves 10 extending in the tire circumferential direction Tc and rib rows 20 formed by being partitioned into the circumferential grooves are formed in the tread portion of the tire according to the present embodiment. Has been. Specifically, the tread portion is provided with a center rib row 21 and rib rows 22 to 29 formed outside the center rib row 21 in the tread width direction Tw. Note that the tread pattern is symmetrical with respect to the tire equator line CL.

  Also, as shown in the figure, when the tire touches down on the road surface at the time of touchdown Ttd at the time of landing, the ground contact area of the tire is a center rib row in the vicinity of the point T1 (time “0”) at the start of touching 21 is a grounding area Za including a grounding surface Z21 of 21, a grounding surface Z22 of the rib row 22, and a grounding surface Z26 of the rib row 26. The grounding area extends to the grounding region Zb with the passage of time. Go.

  Further, the ground contact area in the minute section dt increases as the tire load Wdt increases. Specifically, in the touchdown time Ttd, the tire load Wdt increases in the minute interval dt in which time has elapsed, and thus the contact area increases. Further, when the increase in the tire load Wdt is stabilized, the contact area stops spreading in the maximum contact area Zb.

In such a case, the contact area to which the first tangential force Fdt is applied increases at the time of touchdown Ttd. In consideration of this point, the tire wear prediction device distributes the first tangential force Fdt in the minute section dt to the second tangential force F _n dt applied to each of the contact surfaces of the rib rows 21 to 29. The second tangential force F _n dt of each of the contact surfaces of the rib rows 21 to 29 is expressed by the following equation.

  In the above formula, Zdt represents the ground contact area Zdt of the entire tire in the minute section dt. Further, the tire wear prediction device extracts the tire load dt of the minute section dt based on the load information, and acquires the entire contact area Zdt of the tire corresponding to the extracted tire load dt. In addition, since this contact area Zdt can be measured based on the tire load applied to the pneumatic tire having the normal internal pressure, it is preferable to measure the contact area Zdt in advance for each tire load Wdt in the minute section dt. Moreover, it is preferable that the normal internal pressure conforms to the regulations by TRA (American Tire Rim Association).

Further, _{Z n} denotes a ground contact area _{Z n} of the ground plane of each respective rib columns 20. Note that n is assigned according to the number of ground planes of each rib row 20, and in the example of FIG. 5, since nine rib rows 20 are formed, a numerical value of “1-9” is applicable. To do.

In this way, the tire wear prediction device distributes the first tangential force Fdt in the minute section dt to the second tangential force F _n dt corresponding to each of the ground contact surfaces of the rib rows 21 to 29.

In step S1215, the tire wear prediction device calculates wear energy E1 _n dt for each rib row 21 to 29 in the minute section dt based on the second tangential force F _n dt, slip rate information, and tire speed information. To do. Specifically, the tire wear prediction device calculates the slip ratio Sdt for each minute section dt based on the above-described two equations. Further, the wear energy E1 _n dt for each minute section dt is calculated by the following equation.

In the above formula, Sdt represents the slip ratio Sdt in the minute section dt, and Vdt represents the tire speed Vdt. In other words, the tire wear prediction device calculates the slip amount by multiplying the slip rate Sdt by the tire speed Vdt. Further, as shown in the above formula 1, generally, a shearing force is used as the wear energy. However, in the present embodiment, as shown in the above formula, the second tangential force F _n dt is used as the shearing force, and each minute energy is used. The wear energy E1 _n dt of each rib row in the section dt is calculated.

In step S1216, the tire wear prediction apparatus acquires the wear energy E1 _n of each rib row per landing in the touchdown running state by integrating the wear energy E1 _n dt of each rib row in each minute section dt. To do. Specifically, the tire wear prediction device integrates the wear energy E1 _n dt based on the relationship between the touchdown time Ttd and the minute interval dt, and wears the ground surface wear energy E1 _n at the touchdown time Ttd. Is calculated. The wear energy E1 _n is calculated for each ground contact surface of each of the rib rows 21 to 29. The wear energy E1 _n is calculated by the following formula.

(1.4) Process for calculating total wear energy Next, the process of step S130 for calculating the total wear energy E will be described in detail.

  In step S131, the tire wear prediction device acquires the use frequency of a plurality of travel states. Specifically, the tire wear prediction apparatus acquires the landing count TD and the travel distances L1 to L5. These pieces of information are preferably acquired from actual travel records of actual travel of the aircraft. The travel distances L1 to L5 may be acquired by simulation.

In step S132, the tire wear prediction device multiplies the wear energies E1 to E6 corresponding to a plurality of travel states by the use frequencies corresponding to the plurality of travel states for each of the plurality of travel states, and accumulates the multiplication results. Thus, the total wear energy EA accumulated in the tire is calculated. Specifically, the tire wear prediction device calculates the total wear energy EA based on the following equation. The total wear energy EA is calculated for each rib row, and is calculated as the total wear energy EAn (rib row is n).

(1.5) Calculation Method of Wear Amount Predicted Value Next, with reference to FIG. 6, a process for calculating a predicted tire wear amount based on the wear energy En in step S140 described above will be described. FIG. 6 is a flowchart for explaining processing for calculating a predicted tire wear amount according to the present embodiment.

  In step S141, the tire wear prediction device acquires the wear resistance index Gl of the tread rubber disposed in the tread portion of the tire. Specifically, the standard temperature of a rubber sample equivalent to the rubber of the tread portion of a tire (for example, a tire having a tire size of 1400 × 530 × R23) for which the wear life is predicted by a Lambourne wear test defined in JIS K6264 ( For example, the wear resistance index Gl at 25 ° C.) is obtained and input to the tire wear prediction apparatus.

  In step S142, the tire wear prediction apparatus multiplies the wear energy En and the wear resistance index Gl to calculate a predicted tire wear amount.

Specifically, tire wear prediction apparatus, a wear resistance index Gl, calculates the result of multiplying the reciprocal 1 / _{E n} wear energy _{E n} as a wear rate (Gl / _{E n).} Here, n is a number given according to the number of ground planes of each rib row 21 to 29. That is, at this time, the tire wear prediction device calculates the wear rate (Gl / E _n ) for each ground contact surface of each rib row 21 to 29. Further, the tire wear prediction device multiplies each wear rate by the use period M of the pneumatic tire, thereby predicting the wear amount D _n (= M for each ground contact surface of each rib row 21 to 29. (Gl / E _n )) is calculated.

The tire wear prediction device can predict the wear life of the tire. The tire wear prediction device can predict the wear life of the tire based on a value obtained by multiplying the wear rate (Gl / E _n ) by the depth of the remaining groove until reaching the tire rejection limit. Note that the depth of the remaining groove until reaching the tire rejection limit is a value obtained by subtracting 1.0 mm, which is the tire rejection limit, from the depth NSD of the circumferential groove 10 formed in the tread portion. preferable.

Specifically, tire wear prediction apparatus, the wear life prediction value Tl _n for each respective rib columns 21 to 29 by calculating the following equation, it is possible to predict the wear life of the tire.

  In the above formula, the case where the tire rejection limit is 1.0 mm is taken as an example, but the present invention is not limited to this, and an appropriate value may be set.

(2) Tire Wear Prediction Device FIG. 7 shows an outline of a computer 300 as a tire wear prediction device (simulation device) that executes a tire wear prediction method according to an embodiment of the present invention. As shown in the figure, the computer 300 includes a main body 310 including a storage unit (not shown) such as a semiconductor memory and a hard disk, a processing unit (not shown), an input unit 320, and a display unit 330. . A process part performs the process in connection with the tire wear prediction method of the pneumatic tire demonstrated using FIG.

  The computer 300 may be provided with a removable storage medium (not shown) and a driver capable of writing / reading the storage medium. A program for executing processing related to the tire wear prediction method for a pneumatic tire described with reference to FIGS. 1 to 7 may be recorded in a storage medium in advance, and the program read from the storage medium may be executed. The program may be stored (installed) in the storage unit of the computer 300 and executed. Although not shown, the computer 300 may be connectable to a network, for example. A program for executing processing related to the tire wear prediction method may be acquired via a network.

(3) Action / Effect In the tire wear prediction method according to the present embodiment, the plurality of wear energies E1 to E6 corresponding to each of the plurality of running states and the usage frequency of each of the plurality of running states are multiplied for each running state. At the same time, the total wear energy EA accumulated in the tire is calculated by integrating the multiplication results, and the wear amount of the tire is predicted based on the total wear energy EA.

  As described above, according to the tire wear prediction method, tire wear is predicted by distinguishing a plurality of traveling states, so that the amount of tire wear can be predicted with higher accuracy than when not distinguished.

  Further, in the tire wear prediction method according to the present embodiment, based on the measurement result by the drum type maneuverability tester, the speed information, the load information, and the slip rate information at the time of touchdown at the time of landing are acquired, and these Based on the information, the wear energy E1 per landing in the touchdown running state is calculated.

  As described above, according to such a tire wear prediction method, the wear energy E1 of the tire in which the tire is suddenly accelerated and slipped in the touch-down running state, and the wear energy E2 to E6 in the running state other than the touch-down state. Therefore, the tire wear amount can be predicted with high accuracy compared with the case where the tire wear amount is predicted without distinction.

Further, according to the tire wear prediction method, when calculating the wear energy E1 in the touchdown running state, the friction coefficient (dynamic friction coefficient) μ, speed information, load information, and slip ratio information are acquired, Based on these pieces of information, the first tangential force Fdt in the minute section dt of the touchdown time Ttd is calculated. In the tire wear prediction method, the proportional relationship between the ground contact area of the rib rows 21 to 29 and the ground contact area Zdt of the minute section dt with respect to the first tangential force Fdt applied to the entire tire. Based on the above, the second tangential force F _n dt is calculated for each of the rib rows 21 to 29. In the tire wear prediction method, the wear energy E1 _n dt in the minute section dt is calculated based on the second tangential force F _n dt, slip ratio information, and tire speed information. In the tire wear prediction method, the wear energy E1 _n dt is integrated to calculate the wear energy E1 _n for each contact surface of the rib rows 21 to 29.

As described above, in the tire wear prediction method, the wear energy E1 _n in the touch-down running state is calculated in consideration of changes in tire speed, tire load, slip ratio, tire contact area, and the like during landing. Therefore, it is possible to predict wear with high accuracy in accordance with the actual situation.

  Further, according to the tire wear prediction method, each of the decelerating traveling state after touchdown immediately after landing, the turning traveling state, the decelerating traveling state, the free rolling traveling state, and the pushback traveling state during taxi traveling. The wear energy E2 to E6 per unit travel distance is calculated by distinguishing the travel state, so that more accurate wear prediction can be performed as compared with the case where each travel state having different use conditions is not distinguished. .

  Further, according to the tire wear prediction method, the wear energy E1n is multiplied by the landing frequency TD, and the wear energy E2 to E6 per unit travel distance is multiplied by the travel distance L1 to 5 corresponding to each travel state. At the same time, the total wear energy EAn is calculated by integrating the multiplication results. That is, according to the tire wear prediction method, the total wear energy En is calculated using the landing count TD and the travel distances L1 to 5 as correction values, and therefore the landing count TD and the travel distances L1 to 5 are not used. In comparison, the total wear energy En with higher accuracy can be calculated.

  As described above, according to the tire wear prediction method according to the present embodiment, it is possible to predict the wear amount of a tire used in an aircraft with high accuracy.

  Further, in the tire wear prediction method, it is not necessary to perform a correction process based on an actual measurement value obtained by actual measurement as in the prior art, and the efficiency of the process in tire wear prediction can be improved.

  Further, in the tire wear prediction method, the wear amount prediction value is calculated based on the above-described total wear energy EA and the wear resistance index G1, so that the wear up to the depth of the circumferential groove 10 at the tire rejection limit is calculated. Life prediction can be performed with high accuracy.

  In addition, according to the tire wear prediction method, the wear energy E1 to E6 can be acquired based on information that can be measured by a measuring device such as a drum-type maneuverability tester. The amount of wear can be predicted efficiently.

[Other Embodiments]
Although the contents of the present invention have been disclosed through the embodiments of the present invention as described above, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments and examples will be apparent to those skilled in the art. For example, the embodiment of the present invention can be modified as follows.

  For example, in the above-described embodiment, as a pneumatic tire, a tire used for an aircraft has been described as an example, but the pneumatic tire is not limited thereto. The wear prediction method according to the present embodiment is useful for wear prediction of, for example, a tire whose speed rapidly increases or decreases, or a tire in which a very large slip occurs.

  As described above, the present invention naturally includes various embodiments that are not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

[Example]
Next, in order to further clarify the effect of the present invention, a comparative evaluation performed using a tire wear prediction method according to the following examples will be described.

(1) Description of Examples First, two sample tires 1 and 2 are prepared, and the total wear energy EAn calculated by the tire wear prediction method according to the present embodiment is calculated for each of the sample tires 1 and 2. did. In addition, n is a numerical value attached | subjected according to the number of the grounding surfaces of each rib row.

  Further, the sample tire 1 has a bias structure. As the sample tire 1, a tire provided with seven rib rows at the tread portion was used. The sample tire 2 has a radial structure. As the sample tire 2, a tire provided with seven rib rows in the tread portion was used.

  Moreover, in the tire wear prediction method according to the present embodiment, the wear energy E1 is calculated using speed information, load information, and slip rate information measured under the following conditions.

・ Tire size: 1400X530R23
・ Rim size: 23 inches
・ Internal pressure condition: 1440 kPa
・ Measuring device: Drum-type maneuverability tester ・ Measuring method: A test in which a non-rotating tire is pressed against a drum rotating at a peripheral speed equivalent to the landing speed at a constant speed until a specified load is generated in a shaft-free state. It is. The pressing speed is equivalent to the speed at which the tire is pressed against the road surface during actual landing.

  In the tire wear prediction method according to the present embodiment, the wear energies E2 to E6 were measured under the following conditions.

・ Tire size: 1400X530R23
・ Rim size: 23 inches
・ Internal pressure condition: 1440 kPa
Measuring device: Measuring device according to Patent No. 4198610 Measuring method: According to Patent No. 4198610 Further, FIG. 9 is calculated based on the tire wear prediction method according to the present embodiment for the sample tire 1. is a graph showing the calculation results of the wear energy E _n. 10, to the sample tire 2, was calculated on the basis of the tire wear prediction method according to the present embodiment is a graph showing the calculation results of the wear energy E _n. 9 to 10, the center rib row is “rib row 1”, and the rib rows formed on the outer side from the center rib row in the tread width direction Tw are assigned with a larger number.

(2) the evaluation method sample tires 1 and 2, the calculation result of the wear energy E _n calculated on the basis of the tire wear prediction method according to the present embodiment, by comparing the wear amount of the measured value, the evaluation went.

Here, the wear energy _{E n} and the wear amount _{D n,} a relationship of wear amount _D n = (abrasion resistance index Gl * depth NSB) / Wear energy _{E n.} Here, since the wear resistance index Gl and the groove depth NSB are constant values (constants), if there is a proportional correlation between the measured wear amount and the predicted wear energy, the accuracy of the predicted value is It will be expensive.

Thus, the wear energy E _n of the sample tire 1 to 2, in the wear amount by actual measurement of the pneumatic tire was performed about 300 times landing, it was evaluated whether correlation proportional seen.

(3) Evaluation results and wear energy E _n of the sample tires 1 and 2 calculated by tire wear prediction method according to this embodiment, evaluation results of the wear amount D _n by measured values will be described with reference to FIG. 10 . FIG. 10 is a graph showing the evaluation results. In the figure, the horizontal axis indicates the wear energy, and the vertical axis indicates the wear amount.

Further, in the figure, plotted to correspond to the horizontal axis wear energy E _n in the rib columns of each sample tire 1 to 2 calculated by tire wear prediction method according to the embodiment, each of the sample tires 1 to 2 It was plotted in correspondence with the vertical axis of the wear amount D _n of a tire according to the measured values at the rib columns.

As shown in the figure, between the wear energy E _n calculated on the basis of the method according to the present embodiment, the wear amount D _n of the tire as measured by actual measurement, was observed correlation substantially proportional.

Therefore, it has been proved that the tire wear prediction method according to the present invention can predict the wear amount of the tire with high accuracy.

CL: tire equator line, Za: ground contact region, Zb: ground contact region, Z21: ground contact surface, Z22: ground contact surface, Z26: ground contact surface, Tc: tire circumferential direction, Tw: tread width direction, 10: circumferential groove, 21 ... center rib row, 22 to 29 ... rib row, 300 ... computer, 310 ... main body portion, 320 ... input portion, 330 ... display portion

Claims (7)

A tire wear prediction method for predicting aircraft tire wear,
Step A for obtaining a plurality of wear energies En corresponding to each of a plurality of running states classified according to use conditions;
Step B of multiplying the plurality of wear energies En and the frequency of use of each of the plurality of running states for each of the plurality of running states, and calculating the total wear energy EA accumulated in the tire by integrating the multiplication results. When,
A tire wear prediction method, comprising: calculating a wear amount of the aircraft tire based on the total wear energy EA. The plurality of running states are:
A touchdown running state indicating a running state from a time T1 when the aircraft tire has landed to a time T2 at which the tire rotation speed reaches a peak; and
A touchdown-decelerated running state indicating a running state of the aircraft tire from the time point T2 to a time point T3 when the first braking state ends;
A taxi running state indicating a running state in which the aircraft travels without any external force during the period from time T3 to the next takeoff;
Including a pushback traveling state indicating a traveling state in which the aircraft travels being pulled by a special vehicle,
The taxi running state is
Free rolling running state indicating a running state in which the aircraft travels straight by rolling without external force acting on the aircraft tire;
A decelerating traveling state indicating a traveling state in which braking force is applied to the aircraft tire and traveling;
The tire wear prediction method according to claim 1, further comprising a turning traveling state indicating a traveling state in which the aircraft tire turns and travels. The step A includes the plurality of wear energies En,
Wear energy E1 per landing in the touchdown running state;
Wear energy E2 per unit travel distance in the decelerated travel state after the touchdown,
Wear energy E3 per unit travel distance in the free rolling travel state;
Wear energy E4 per unit travel distance in the deceleration travel state;
Wear energy E5 per unit travel distance in the turning state,
Obtaining the wear energy E6 per unit travel distance in the pushback travel state,
In step B, as the usage frequency corresponding to each of the plurality of running states,
Number of times TD of the touchdown running state;
Travel distance L1 in the decelerating travel state after the touchdown,
A travel distance L2 in the free rolling travel state;
A travel distance L3 in the decelerated travel state;
A travel distance L4 in the turning travel state;
Obtaining a travel distance L5 in the pushback travel state;
The tire wear prediction method according to claim 2, further comprising: calculating the total wear energy EA using a calculation formula of EA = E1 × TD + E2 × L1 + E3 × L2 + E4 × L3 + E5 × L4 + E6 × L5. The aircraft tire has a plurality of rib rows,
4. The tire wear prediction method according to claim 1, wherein in step B, the total wear energy EA is calculated for each rib row. 5. In step A,
In the touch-down running state indicating the running state from the time point T1 when the aircraft tire has landed to the time point T2 when the tire rotation speed reaches a peak, including the step of acquiring the wear energy E1 of the rib row per landing,
The step of obtaining the wear energy E1 includes:
By reproducing the touchdown running state using a test machine, the entire tread surface of the tire tread surface is divided into each minute section in a plurality of minute sections obtained by dividing the period from the time point T1 to the time point T2 along the time axis. Obtaining a first tangential force applied to
Obtaining the second tangential force of each rib row in each of the micro sections by distributing the first tangential force in proportion to the contact area of each rib row in each of the micro sections;
Using the second tangential force as a shear force to calculate the wear energy of each rib row in each minute section;
5. The step of acquiring wear energy E <b> 1 of each rib row per landing in a touchdown traveling state by integrating the wear energy for each rib row in each of the minute sections. The tire wear prediction method described. In step C,
Obtaining a wear resistance index Gl;
The tire wear prediction method according to claim 1, further comprising a step of multiplying the overall wear energy E by the wear resistance index Gl to calculate a predicted value of a wear amount. .   A tire wear prediction apparatus for executing the tire wear prediction method according to any one of claims 1 to 6.

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