JP2016011906A - Abrasion prediction method of tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an abrasion prediction method of a tire that can enhance a prediction accuracy.SOLUTION: A wear prediction method of a tire includes: preparing a plurality of test tires rotatable with a center shaft as a center with a plurality of groove patterns having the same or similar design provided in a peripheral direction of the center shaft; defining an estimation section of the test tire on the basis of at least one of the blocks defined by two lug grooves arranged in a pitch and peripheral direction defined by one groove pattern; defining abrasion energy of at least two measurement regions defined in the peripheral direction in the smallest section; and predicting a heel-and-toe abrasion of the test tire on the basis of a difference between the abrasion energy of a first measurement region and the abrasion energy of a second measurement region.

Description

  The present invention relates to a tire wear prediction method.

  In tire development, tire wear is evaluated. The tire wear may be evaluated by actually running the vehicle with the tire attached thereto. However, actually running the vehicle results in longer time required for evaluation and increased man-hours. Therefore, the tire wear energy may be evaluated by measuring the friction energy (wear energy) of the tire with a testing machine and predicting the wear of the tire based on the measurement result.

  As the form of tire wear, shoulder wear where the shoulder portion of the tire wears earlier than other portions, center wear where the center portion of the tire wears earlier than other portions, and the land portion of the tire with respect to the circumferential direction of the tire. Heel and toe wear that wears unevenly is known.

  Patent Document 1 discloses an example of a method for measuring the wear energy of the first and second wear portions of the tread surface of a tire divided by sipe with a tester and evaluating the heel and toe wear based on the measurement result. Has been.

JP 2013-221847 A

  When the tire wear is predicted using the measurement result of the tire friction energy, and the tire wear is evaluated based on the prediction result, it is desired to improve the prediction accuracy of the tire wear.

  An object of an aspect of the present invention is to provide a tire wear prediction method capable of improving prediction accuracy.

  An aspect of the present invention is to prepare a test tire that is rotatable about a central axis and is provided with a plurality of groove patterns of the same or similar design in the circumferential direction of the central axis, and one groove pattern The evaluation section of the test tire is defined based on at least one of the block defined by the pitch defined by 2 and the two lug grooves arranged in the circumferential direction, and the first arrival including the first arrival portion of the evaluation section Measuring the frictional energy of the first measurement site defined in the region, measuring the frictional energy of the second measurement site defined in the rearward region including the rearward portion of the evaluation section, and the first Predicting the heel and toe wear of the test tire based on the difference between the friction energy of the measurement site and the friction energy of the second measurement site, and a tire wear prediction method comprising: Subjected to.

  According to the aspect of the present invention, the evaluation section of the test tire is defined based on at least one of the pitch and the block, and the friction energy of the first measurement region in the first arrival area of the evaluation section and the second measurement region in the second arrival area. By measuring the friction energy, it is possible to improve the prediction accuracy of the heel and toe wear of the test tire in the evaluation section based on the measurement result.

  Heel and toe wear occurs due to the difference between the friction energy at or near the first part of the evaluation section and the friction energy at or near the rear part. Accordingly, heel and toe wear can be accurately predicted by determining the measurement site in each of the first arrival region and the later arrival region and measuring the friction energy of each of the plurality of measurement regions. The plurality of measurement sites may be arranged at the same position or in different positions with respect to the direction parallel to the central axis.

  The first landing portion refers to a portion of the evaluation section that first contacts the road surface when the tire travels on the road surface while rotating about the central axis. The rear landing portion refers to a portion of the evaluation section that contacts the road surface later when the tire travels on the road surface while rotating about the central axis. That is, one of the one end portion and the other end portion of the evaluation section with respect to the circumferential direction is a first arrival portion, and the other is a rear arrival portion.

  The evaluation section refers to a portion defined in the tread portion of the tire based on at least one of pitch and block. The evaluation section is a measurement target portion of tire frictional energy, a prediction target portion of tire heel and toe wear, and a evaluation target portion of tire heel and toe wear.

  The pitch refers to a portion defined by one groove pattern in the tread portion of the tire when a plurality of groove patterns having the same or similar design are provided in the circumferential direction of the tire. The groove pattern includes at least one of a main groove, a lug groove, and a sipe. The lug grooves and sipes include notches or notches that do not penetrate the land. The pitch may be defined by two lug grooves arranged in the circumferential direction of the tire, or may be defined by two sipes arranged in the circumferential direction of the tire. The pitch may be defined by a lug groove having a first width arranged in the circumferential direction of the tire and a lug groove having a second width different from the first width, or arranged in the circumferential direction of the tire. You may partition by a lug groove and a sipe. The two lug grooves defining the pitch may be arranged adjacent to each other in the tire circumferential direction, or another groove may be arranged between the two lug grooves. Similarly, the two sipes defining the pitch may be disposed adjacent to each other in the circumferential direction of the tire, or another groove may be disposed between the two sipes.

  The block refers to a portion defined in the tread portion of the tire by two lug grooves adjacent in the circumferential direction of the tire. The block may be defined by lug grooves of the same width adjacent to each other in the circumferential direction of the tire, or a first width of the lug groove adjacent to the circumferential direction of the tire and a second width different from the first width. It may be partitioned with a lug groove.

  A lug groove means a lateral groove having a width of 1.5 mm or more. The lug groove has a width of 1.5 mm or more, may have a depth of 4.0 mm or more, and may partially have a depth of less than 4.0 mm. Sipe refers to a transverse groove having a width of less than 1.5 mm.

  In the aspect of the present invention, a plurality of the evaluation sections are defined in the circumferential direction, and the friction energy of the first measurement part and the friction energy of the second measurement part are measured for each of the plurality of evaluation sections. Predicting the heel and toe wear based on the differences derived for each of a plurality of the evaluation zones.

  Thereby, the heel and toe wear which generate | occur | produces in each of the evaluation division prescribed | regulated by the circumferential direction in a test tire can be estimated and evaluated. For example, heel and toe wear can be predicted for each of a plurality of evaluation sections adjacent in the circumferential direction. Further, it is possible to predict the step shape of the evaluation section generated by the heel and toe wear, predict the step amount, and predict the irregular heel and toe wear form for each evaluation section. It is also possible to predict the overall heel and toe wear tendency that occurs in the test tire.

  The level difference of the evaluation section refers to the difference between the distance between the central axis and the first arrival part and the distance between the central axis and the rear arrival part with respect to the radial direction with respect to the central axis. In other words, the level difference of the evaluation section refers to the difference between the height of the first arrival part and the height of the rear arrival part. The step amount of the evaluation section refers to the value of the step of the evaluation section.

  In the aspect of the present invention, at least two kinds of dimensions of the evaluation section may be determined with respect to the circumferential direction.

  Thereby, the form of the heel and toe wear for every evaluation division according to the dimension of the circumferential direction can be estimated. It is also possible to predict the overall heel and toe wear tendency that occurs in the test tire.

  In the aspect of the present invention, the first measurement site is defined in the first arrival part, the second measurement site is defined in the rear arrival part, and the first measurement site and the second measurement site in the circumferential direction. At least one measurement site is defined between the first measurement site and the second measurement site as a reference site, friction energy of the reference site and the first measurement site and Calculating a first difference between the other friction energy of the second measurement site and calculating a second difference between the friction energy of the reference site and the friction energy of the at least one measurement site. And predicting the heel and toe wear based on the first difference and the second difference.

  Thereby, the shape of the evaluation section which changes with heel and toe wear can be accurately predicted.

  In an aspect of the present invention, at least two or more lane regions having a predetermined width in the direction parallel to the central axis are set, and the first measurement site and the second measurement site are defined in each of the plurality of lane regions. May be.

  As a result, even if the groove pattern is different in the direction parallel to the central axis, by predicting the heel and toe wear in each of the plurality of lane regions, it is possible to accurately predict the form of the heel and toe wear according to the groove pattern. it can. That is, for example, when the test tire is a tire having a so-called left-right asymmetric pattern, there is a high possibility that the frictional energy is different between the right region and the left region of the tread portion of the test tire. By setting the first lane region to the right region of the tread portion and the second lane region to the left region of the tread portion, the difference in frictional energy between the left and right of the tread portion in the left and right asymmetric pattern test tire is obtained. In addition, heel and toe wear in the right region of the tread portion of the test tire and heel and toe wear in the left region of the tread portion of the test tire can be accurately predicted. The predetermined width of the first lane region and the predetermined width of the second lane region are preferably 5 mm or less, for example.

  In the aspect of the present invention, the first portion at one end of the tread development width of the test tire and the second portion on the equator plane side of the test tire from the first portion, and the tread development width of the test tire. Including a third portion at the other end and a fourth portion on the equatorial plane side of the test tire with respect to the third portion, the measurement portion being defined, and a direction parallel to the central axis The distance between the first part and the second part and the distance between the third part and the fourth part may each be 30% or less of the tread deployment width. The region defined by 30% or less of the tread development width TDW is generally said to be a portion where heel and toe wear is likely to occur.

  Thereby, the form of the heel and toe wear in the shoulder portion of the test tire, which is a portion where the heel and toe wear is likely to occur, can be accurately predicted.

  In the aspect of the present invention, the measurement part is defined between a fifth part of the ground contact edge of the test tire and a sixth part on the equator plane side of the test tire from the fifth part; Defining a measurement part between a seventh part closest to the ground contact end in the main groove and an eighth part closer to the ground contact end than the seventh part, and in a direction parallel to the central axis The distance between the fifth part and the sixth part may be 5 mm or less, and the distance between the seventh part and the eighth part may be 10 mm or less.

  Thereby, the form of the heel and toe wear between the fifth part and the sixth part and between the seventh part and the eighth part, which are parts where heel and toe wear is likely to occur, can be accurately predicted. The ground contact end defined by 5 mm or less and the outermost main groove end defined by 10 mm or less are generally said to be portions where heel and toe wear is likely to occur.

  In an aspect of the present invention, the method includes extracting a maximum width portion having a maximum width in the lug groove or the sipe of the evaluation section, and the measurement portion is separated from the maximum width portion in a direction parallel to the central axis. It may be set within a range of 5 mm.

  Thereby, the form of the heel and toe wear in the maximum width portion or the vicinity thereof, which is a portion where heel and toe wear is likely to occur, can be accurately predicted. The range defined by 5 mm or less is generally said to be a portion where heel and toe wear is likely to occur.

  In an aspect of the present invention, the method includes extracting a maximum depth portion having a maximum depth in the lug groove or the sipe of the evaluation section, and the measurement portion has the maximum depth with respect to a direction parallel to the central axis. It may be determined within a range of 5 mm from the part.

  As a result, it is possible to accurately predict the form of heel and toe wear at or near the maximum depth, which is a portion where heel and toe wear is likely to occur. The range defined within 5 mm is generally said to be a portion where heel and toe wear is likely to occur.

  In an aspect of the present invention, the method includes extracting a maximum inclination portion having a maximum inclination angle with respect to a tire width direction in the lug groove or the sipe of the evaluation section, and the measurement portion is related to a direction parallel to the central axis. It may be determined within a range of 5 mm from the maximum inclined portion.

  Thereby, it is possible to accurately predict the form of heel and toe wear at or near the maximum slope portion where heel and toe wear is likely to occur. The range defined by 5 mm or less is generally said to be a portion where heel and toe wear is likely to occur.

  In the aspect of the present invention, for the reference tire, the friction of the first measurement portion and the second measurement portion of the reference tire is defined under the same condition as that for defining the evaluation section and measuring the friction energy of the test tire. Measuring energy, determining a reference value for the friction energy based on a difference between friction energy of the first measurement portion and friction energy of the second measurement portion of the reference tire, and the reference value Comparing the frictional energy of the first measurement site and the second measurement site of the test tire and predicting the heel and toe wear of the test tire based on the comparison result. .

  Thereby, heel and toe wear can be accurately predicted based on the reference value.

  In an aspect of the present invention, the friction energy of the measurement site defined in the evaluation section of the test tire is measured under each of the reference use condition and the evaluation use condition, and the test measured under the reference use condition Determining a reference value for the frictional energy based on the difference between the frictional energy of the first measurement part and the second measurement part of the tire, and measuring the reference value and the evaluation use condition Comparing the frictional energy of the measured portion of the test tire that has been performed and predicting the heel and toe wear of the test tire under the evaluation use condition based on the comparison result.

  Thereby, heel and toe wear can be accurately predicted based on the reference value.

  In the aspect of the present invention, the difference between the friction energy of the first measurement site and the friction energy of the second measurement site of the test tire is the difference between the friction energy of the first measurement site and the friction energy of the second measurement site. May be included.

  Thereby, the progress state of heel and toe wear can be accurately predicted.

  In an aspect of the present invention, the method includes setting a camber angle of the test tire, and the test tire has a first portion and a load at ground contact different from the first portion in a direction parallel to the central axis. A second portion larger than one portion, and the first measurement site and the second measurement site may be defined as at least the second portion.

  Thereby, the form of the heel and toe wear of the 2nd part which is a part which heel and toe wear is easy to accelerate by camber angle can be predicted with sufficient accuracy.

  According to the aspect of the present invention, a tire wear prediction method capable of improving prediction accuracy is provided.

FIG. 1 is a cross-sectional view showing an example of a tire according to the first embodiment. FIG. 2 is an enlarged cross-sectional view of a part of the tire according to the first embodiment. FIG. 3 is a schematic diagram for explaining a tread development width of the tire according to the first embodiment. FIG. 4 is a schematic diagram for explaining the tread development width of the tire according to the first embodiment, and is an enlarged view of a part of FIG. 3. FIG. 5 is a schematic diagram illustrating an example of a processing apparatus according to the first embodiment. FIG. 6 is a flowchart illustrating an example of a procedure of the tire wear prediction method according to the first embodiment. FIG. 7 is a diagram illustrating an example of a tread portion of the tire according to the first embodiment. FIG. 8 is a diagram illustrating an example of a tread portion of the tire according to the first embodiment. FIG. 9 is a schematic diagram for explaining an evaluation section and a measurement site according to the first embodiment. FIG. 10 is a schematic diagram for explaining an evaluation section and a measurement site according to the first embodiment. FIG. 11 is a schematic diagram for explaining an evaluation section and a measurement site according to the first embodiment. FIG. 12 is a schematic diagram for explaining an evaluation section and a measurement site according to the first embodiment. FIG. 13 is a schematic diagram for explaining an evaluation section and a measurement site according to the first embodiment. FIG. 14 is a schematic diagram for explaining a measurement site according to the first embodiment. FIG. 15 is a diagram schematically illustrating an example of a prediction result of heel and toe wear according to the first embodiment. FIG. 16 is a diagram schematically illustrating an example of an evaluation section according to the first embodiment. FIG. 17 is a schematic diagram for explaining a measurement site according to the first embodiment. FIG. 18 is a side view schematically showing an example of a tire according to the second embodiment. FIG. 19 is a side view schematically showing an example of a tire according to the third embodiment. FIG. 20 is a schematic diagram for explaining an evaluation section and a measurement site according to the fourth embodiment. FIG. 21 is a flowchart illustrating an example of a procedure of a tire wear prediction method according to the fourth embodiment. FIG. 22 is a diagram schematically illustrating an example of a prediction result of heel and toe wear according to the fourth embodiment. FIG. 23 is a plan view showing a part of the tread portion of the tire according to the fifth embodiment. FIG. 24 is a plan view showing a part of the tread portion of the tire according to the fifth embodiment. FIG. 25 is a plan view showing a part of the tread portion of the tire according to the sixth embodiment. FIG. 26 is a plan view showing a part of the tread portion of the tire according to the seventh embodiment. FIG. 27 is a plan view showing a part of the tread portion of the tire according to the seventh embodiment, and is an enlarged view of a part of FIG. 26. FIG. 28 is an enlarged view of a part of the tread portion of the tire according to the eighth embodiment. FIG. 29 is an enlarged view of a part of the tread portion of the tire according to the ninth embodiment. FIG. 30 is an enlarged view of a part of the tread portion of the tire according to the tenth embodiment. FIG. 31 is a flowchart illustrating an example of a procedure of a tire wear prediction method according to the eleventh embodiment. FIG. 32 is a schematic diagram for explaining a method of predicting heel and toe wear according to the twelfth embodiment. FIG. 33 is a schematic diagram for explaining an example of a tire wear prediction method according to the thirteenth embodiment.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings, but the present invention is not limited thereto. The components of the embodiments described below can be combined as appropriate. Some components may not be used.

  In the following description, an XYZ orthogonal coordinate system is set, and the positional relationship of each part will be described with reference to this XYZ orthogonal coordinate system. One direction in the horizontal plane is defined as the X-axis direction, a direction orthogonal to the X-axis direction in the horizontal plane is defined as the Y-axis direction, and a direction orthogonal to each of the X-axis direction and the Y-axis direction is defined as the Z-axis direction. Further, the rotation (inclination) directions around the X axis, Y axis, and Z axis are the θX, θY, and θZ directions, respectively.

<First Embodiment>
A first embodiment will be described. FIG. 1 is a cross-sectional view showing an example of a tire 1 according to this embodiment. FIG. 2 is an enlarged cross-sectional view of a part of the tire 1 according to the present embodiment. The tire 1 is rotatable about a central axis (rotating axis) AX. 1 and 2 each show a meridional section passing through the central axis AX of the tire 1. A center axis AX of the tire 1 is orthogonal to the equator plane CL of the tire 1.

  In the present embodiment, the center axis AX and the Y axis of the tire 1 are parallel. That is, in the present embodiment, the direction parallel to the central axis AX is the Y-axis direction. The Y-axis direction is the width direction of the tire 1 or the vehicle width direction. The equatorial plane CL passes through the center of the tire 1 with respect to the Y-axis direction. The θY direction is the rotation direction of the tire 1 (center axis AX). The rotation direction of the tire 1 (center axis AX) may be referred to as a circumferential direction. The X-axis direction and the Z-axis direction are radial directions with respect to the central axis AX. The radial direction with respect to the central axis AX may be referred to as a radial direction. The road surface (ground) on which the tire 1 travels (rolls) is substantially parallel to the XY plane.

  The tire 1 includes a carcass portion 2, a belt layer 3, a belt cover 4, a bead portion 5, a tread portion 10, and a sidewall portion 9. The tread portion 10 is disposed on the tread rubber 6. The sidewall portion 9 is disposed on the sidewall rubber 8. Each of the carcass part 2, the belt layer 3, and the belt cover 4 includes a cord. The cord is a reinforcing material. The cord may be referred to as a wire. Each of the layers including the reinforcing material such as the carcass portion 2, the belt layer 3, and the belt cover 4 may be referred to as a cord layer or a reinforcing material layer.

  The carcass portion 2 is a strength member that forms the skeleton of the tire 1. The carcass part 2 includes a cord. The cord of the carcass portion 2 may be referred to as a carcass cord. The carcass part 2 functions as a pressure vessel when the tire 1 is filled with air. The carcass part 2 is supported by the bead part 5. The bead portion 5 is disposed on each of one side and the other side of the carcass portion 2 with respect to the Y-axis direction. The carcass portion 2 is folded back at the bead portion 5. The carcass portion 2 includes an organic fiber carcass cord and rubber covering the carcass cord. The carcass portion 2 may include a polyester carcass cord, a nylon carcass cord, an aramid carcass cord, or a rayon carcass cord.

  The belt layer 3 is a strength member that maintains the shape of the tire 1. The belt layer 3 includes a cord. The cord of the belt layer 3 may be referred to as a belt cord. The belt layer 3 is disposed between the carcass portion 2 and the tread rubber 6. The belt layer 3 includes, for example, a belt cord made of metal fiber such as steel and rubber covering the belt cord. The belt layer 3 may include an organic fiber belt cord. In the present embodiment, the belt layer 3 includes a first belt ply 3A and a second belt ply 3B. The first belt ply 3A and the second belt ply 3B are laminated so that the cord of the first belt ply 3A and the cord of the second belt ply 3B intersect.

  The belt cover 4 is a strength member that protects and reinforces the belt layer 3. The belt cover 4 includes a cord. The cord of the belt cover 4 may be referred to as a cover cord. The belt cover 4 is disposed outside the belt layer 3 with respect to the central axis AX of the tire 1. The belt cover 4 includes, for example, a cover cord made of metal fiber such as steel and rubber covering the cover cord. The belt cover 4 may include an organic fiber cover cord.

  The bead portion 5 is a strength member that fixes both ends of the carcass portion 2. The bead portion 5 fixes the tire 1 to the rim. The bead portion 5 is a bundle of steel wires. The bead portion 5 may be a bundle of carbon steel.

  The tread rubber 6 protects the carcass portion 2. The tread rubber 6 includes a tread portion 10 and a plurality of grooves 20 provided in the tread portion 10. The tread portion 10 includes a ground contact portion that comes into contact with the road surface. The tread portion 10 includes a land portion disposed between the grooves 20. The surface of the land portion is a ground contact surface that can come into contact with the road surface.

  The side wall rubber 8 protects the carcass part 2. The sidewall rubber 8 is disposed on each of one side and the other side of the tread rubber 6 with respect to the Y-axis direction. The sidewall rubber 8 has sidewall portions 9 disposed on one side and the other side of the tread portion 10 with respect to the Y-axis direction.

  In the present embodiment, the tire outer diameter is OD. The tire rim diameter is RD. The total tire width is SW. The tread ground contact width is W. The tread deployment width is TDW.

  The tire outer diameter OD means the diameter of the tire 1 when the tire 1 is mounted on a specified rim, the inside of the tire 1 is filled with a specified pressure (for example, 230 kPa), and no load is applied to the tire 1. .

  The tire rim diameter RD refers to a wheel rim diameter suitable for the tire 1. The tire rim diameter RD is equal to the tire inner diameter.

  The total tire width SW refers to the tire 1 in a direction parallel to the central axis AX when the tire 1 is mounted on a specified rim, the inside of the tire 1 is filled with air with a specified pressure, and no load is applied to the tire 1. The maximum dimension of That is, the tire total width SW is the most + Y side portion of the sidewall portion 9 disposed on the + Y side of the tread rubber 6 and the most −Y side portion of the sidewall portion 9 disposed on the −Y side. The distance. When the structure which protrudes from the surface of the side wall part 9 is provided in the surface of the side wall part 9, tire total width SW means the largest dimension of the tire 1 regarding the Y-axis direction containing the structure. . The structure protruding from the surface of the sidewall portion 9 includes at least one of characters, marks, and patterns formed by at least a part of the sidewall rubber 8 in the sidewall portion 9.

  The tread ground contact width W refers to the maximum dimension (maximum width) of the ground contact region of the tread portion 10 in the direction parallel to the central axis AX. The contact area of the tread portion 10 means that the tire 1 is mounted on a specified rim, the inside of the tire 1 is filled with a specified pressure (for example, 230 kPa), and a load corresponding to 80% of the load capacity is applied to the tire 1. This refers to the ground contact area of the tire 1 when grounded on a flat road surface.

  The tread deployment width TDW is a development view of the tread portion 10 of the tire 1 when the tire 1 is mounted on a prescribed rim, the inside of the tire 1 is filled with air at a prescribed pressure (for example, 230 kPa), and no load is applied. The linear distance at both ends in.

  The tread development width TDW will be described with reference to FIGS. 3 and 4 are diagrams for explaining the tread development width TDW. FIG. 3 is a diagram schematically showing a meridional section of the tire 1 including the tread portion 10, the sidewall portion 9, and the bead portion 5. FIG. 4 is an enlarged view of portion A in FIG.

  As shown in FIGS. 3 and 4, in the meridional section (YZ plane) of the tire 1, the intersection of the extension line of the profile line of the tread portion 10 and the extension line of the sidewall portion 9 on the −Y side is C1, and the tread portion When the intersection of the extension line of 10 profile lines and the extension line of the sidewall portion 9 on the + Y side is C2, the tread development width TDW is the distance between the intersection C1 and the intersection C2 in the width direction (Y-axis direction). Say.

  FIG. 5 is a diagram illustrating an example of a processing device 50 capable of performing prediction and evaluation of wear of the tire 1 according to the present embodiment. The processing device 50 includes a computer. In the present embodiment, prediction and evaluation of wear of the tire 1 are performed using the processing device 50.

  The processing device 50 is connected to a friction energy tester 57 that can measure the friction energy of the tire 1. The processing device 50 predicts and evaluates the wear of the tire 1 based on the friction energy of the tire 1 measured by the friction energy testing machine 57. Further, the processing device 50 can create an analysis model of the tire 1 that can be analyzed by a computer, and simulate the characteristics of the tire 1. In the present embodiment, the processing device 50 may be referred to as a wear prediction device 50, an evaluation device 50, or a simulation device 50.

  In the present embodiment, the processing device 50 includes a processing unit 50p, a storage unit 50m, and an input / output unit 53. The processing unit 50p and the storage unit 50m are connected via the input / output unit 53.

  The processing unit 50p includes a CPU (Central Processing Unit) and a memory such as a RAM (Random Access Memory). The processing unit 50p includes a calculation unit 51 that performs calculation based on the measurement result of the friction energy tester 57, and an analysis unit 52 that performs prediction and evaluation of wear of the tire 1. The calculation unit 51 and the analysis unit 52 are each connected to the input / output unit 53. The calculation unit 51 and the analysis unit 52 can communicate data via the input / output unit 53.

  The storage unit 50m includes at least one of a volatile memory such as a RAM (Random Access Memory), a non-volatile memory, a fixed disk device such as a hard disk device, a storage device such as a flexible disk and an optical disk. The storage unit 50m stores information for predicting and evaluating the wear of the tire 1.

  The information for predicting and evaluating the wear of the tire 1 includes data related to the running condition of the tire 1 and the load condition of the tire 1. The traveling condition of the tire 1 includes the rotational speed of the tire 1 and the acceleration of the tire 1. The traveling condition of the tire 1 includes at least one of driving, braking, and turning. The turning of the tire 1 includes one or both of a right turn and a left turn. Further, the traveling condition of the tire 1 includes a camber angle. The load condition of the tire 1 includes a force generated in the tire 1 during traveling, and includes at least one of a driving force, a braking force, a turning force, a longitudinal force, and a lateral force. Further, the load condition of the tire 1 includes a load acting on the tire 1.

  The storage unit 50m stores a computer program for performing prediction and evaluation of wear of the tire 1. The computer program can cause the processing device 50 to execute the wear prediction method for the tire 1 according to the present embodiment. The computer program may be referred to as a tire wear prediction computer program or a tire 1 evaluation computer program.

  The input / output unit 53 is connected to the friction energy tester 57 and the terminal device 54. The terminal device 54 is connected to the input device 55 and the output device 56. The input device 55 includes at least one of a keyboard, a mouse, and a microphone. The output device 56 includes at least one of a display device such as a display and a printer.

  The measurement result of the friction energy tester 57 is output to the processing unit 50p via the input / output unit 53. The processing unit 50p acquires the measurement result of the friction energy tester 57. The processing unit 50 p uses the measurement result of the friction energy tester 57 to predict and evaluate the wear of the tire 1. Note that at least a part of the data for predicting and evaluating the wear of the tire 1 may be input from the input device 55.

  The prediction result and the evaluation result of the wear of the tire 1 performed in the processing unit 50p are output to the output device 56 via the input / output unit 53 and the terminal device 54. The output device 56 can output a predicted result of wear of the tire 1 and an evaluation result. When the output device 56 includes a display device, the display device can display the prediction result and the evaluation result of the wear of the tire 1.

  Next, an example of a method for predicting wear of the tire 1 according to the present embodiment will be described. FIG. 6 is a flowchart showing a processing procedure of the wear prediction method for the tire 1 according to the present embodiment. As shown in FIG. 6, the tire 1 wear prediction method according to the present embodiment prepares a tire 1 in which a plurality of groove patterns having the same or similar design are provided in the circumferential direction of the tire 1 (center axis AX). The evaluation section 41 of the tire 1 is defined based on at least one of the step (step SA1) and the block 31 defined by the pitch 31 defined by one groove pattern and the two lug grooves 22 arranged in the circumferential direction. And the step of measuring the friction energy of the measurement site 43A defined in the first arrival part of the evaluation section 41 and the friction energy of the measurement site 43B defined in the rear arrival part of the evaluation section 41 (step SA3). ) And a step of deriving the difference between the friction energy of the measurement site 43A and the friction energy of the measurement site 43B (step SA4), and based on the derived difference There are, comprises a step (step SA5) for predicting the Hiruandotu wear of the tire 1, a.

  FIG. 7 is a diagram illustrating an example of the tread portion 10 of the tire 1. As shown in FIG. 7, the tire 1 has a groove 20 provided in the tread portion 10. The groove 20 includes a main groove 21 extending in the circumferential direction of the tire 1, a lug groove (lateral groove) 22 extending at least partially in the width direction of the tire 1, and a sipe 23 extending at least partially in the width direction of the tire 1; including. A land portion is provided around the groove 20. The land portion is provided between the groove 20 and the groove 20 adjacent to the groove 20. The tread portion 10 includes a plurality of land portions.

  The main groove 21 is formed in the circumferential direction of the tire 1. At least a part of the main groove 21 is provided in the center portion 11 of the tread portion 10 of the tire 1. The main groove 21 has a tread wear indicator inside. The treadwear indicator indicates the end of wear. The main groove 21 has a width of 4.0 mm or more and may have a depth of 5.0 mm or more. In the example shown in FIG. 7, the tire 1 has four main grooves 21.

  At least a part of the lug groove 22 is formed in the width direction of the tire 1. At least a part of the lug groove 22 is provided in the shoulder portion 12 of the tread portion 10 of the tire 1. The shoulder portion 12 is disposed on each of one side (+ Y side) and the other side (−Y side) of the center portion 11 with respect to the width direction (Y-axis direction). The lug groove 22 has a width of 1.5 mm or more. The lug groove 22 may have a depth of 4.0 mm or more, and may partially have a depth of less than 4.0 mm.

  At least a part of the sipe 23 is formed in the width direction of the tire 1. The sipe 23 is formed on the land portion of the tire 1. In the present embodiment, at least a part of the sipe 23 is provided on the shoulder portion 12 of the tread portion 10 of the tire 1. The sipe 23 has a width of less than 1.5 mm.

  In general, the tread portion 10 of the tire 1 is provided with a plurality of groove patterns having the same or similar design in the circumferential direction. Of the plurality of groove patterns provided in the circumferential direction, a region defined by one groove pattern is called a pitch 31. One pitch 31 is defined by one groove pattern.

  That is, the pitch 31 refers to a portion defined in the tread portion 10 of the tire 1 by one groove pattern when a plurality of groove patterns having the same or similar design are provided in the circumferential direction of the tire 1. The groove pattern includes at least one of a main groove 21, a lug groove 22, and a sipe 23. The pitch 31 may be defined by two lug grooves 22 arranged in the circumferential direction of the tire 1. The two lug grooves 22 are of the same or similar design. The pitch 31 may be defined by two sipes 23 arranged in the circumferential direction of the tire 1. The two sipes 23 are of the same or similar design.

  The same or similar lug groove 22 design includes at least one of the width, length, extending direction, number of corners, and corner angles of the lug grooves 22.

  The pitch 31 may be defined by a first width lug groove 22 disposed in the circumferential direction of the tire 1 and a second width lug groove 22 different from the first width. The pitch 31 may be partitioned by lug grooves 22 and sipes 23 arranged in the circumferential direction of the tire 1.

  In the example shown in FIG. 7, one pitch 31 (groove pattern) is defined by two lug grooves 22 arranged in the circumferential direction of the tire 1. In the example shown in FIG. 7, the pitch 31 includes a sipe 23. In the example shown in FIG. 7, the pitch 31 includes a part of the main groove 21.

  The block 32 refers to a portion defined by the tread portion 10 of the tire 1 by two lug grooves 22 adjacent in the circumferential direction of the tire 1. The block 32 may be defined by lug grooves 22 having the same width adjacent to each other in the circumferential direction of the tire 1. The block 32 may be defined by a lug groove 22 having a first width adjacent to the tire 1 in the circumferential direction and a lug groove 22 having a second width different from the first width.

  In the example shown in FIG. 7, one block 32 is arranged for one pitch 31 in the circumferential direction.

  FIG. 8 is a diagram illustrating an example of the tread portion 10 of the tire 1. In the example shown in FIG. 8, a main groove 21, a lug groove 22, and a sipe 23 are provided in the tread portion 10 of the tire 1. In the example shown in FIG. 8, the tire 1 has two main grooves 21.

  In the example illustrated in FIG. 8, the lug groove 22 includes a lug groove 22A and a lug groove 22B provided in the shoulder portion 12 on the + Y side, and a lug groove 22C, a lug groove 22D, and a lug groove 22E provided in the center portion 11. And lug grooves 22F and lug grooves 22G provided in the shoulder portion 12 on the -Y side. The lug grooves 22A, lug grooves 22B, lug grooves 22C, lug grooves 22D, lug grooves 22E, lug grooves 22F, and lug grooves 22G have different designs. As described above, the design of the lug groove 22 includes at least one of the width, length, extending direction, number of corners, and angle of the corners of the lug groove 22.

  In the shoulder portion 12 on the + Y side, the lug grooves 22A and the lug grooves 22B are alternately arranged in the circumferential direction. In the center portion 11, the lug grooves 22C and the lug grooves 22D are alternately arranged in the circumferential direction. In the shoulder portion 12 on the −Y side, three lug grooves 22G are arranged between the lug grooves 22F and the lug grooves 22F.

  In the example shown in FIG. 8, the sipe 23 is provided on the shoulder portion 12 on the −Y side. The sipe 23 is not provided on the shoulder portion 12 on the + Y side.

  In the example shown in FIG. 8, one pitch 31 (groove pattern) includes a part of the main groove 21, the lug groove 22A, the lug groove 22B, the lug groove 22C, the lug groove 22D, a part of the lug groove 22E, and the lug groove 22F. , Lug grooves 22G, and sipes 23. In the example illustrated in FIG. 8, the pitch 31 includes the lug grooves 22 </ b> B, the lug grooves 22 </ b> C, and the lug grooves 22 </ b> F, and the lug grooves 22 </ b> B and 22 </ b> C adjacent to the lug grooves (22 </ b> B, 22 </ b> C, and 22 </ b> F) in the circumferential direction. And the lug groove 22F.

  In the example shown in FIG. 8, the block 32 is defined by a block 32A defined by lug grooves 22A and lug grooves 22B arranged in the circumferential direction, and lug grooves 22B and lug grooves 22B arranged in the circumferential direction. Block 32B, block 32C defined by lug grooves 22F and lug grooves 22G arranged in the circumferential direction, and block 32D defined by lug grooves 22G and lug grooves 22G arranged in the circumferential direction. .

  The evaluation section 41 refers to a portion defined by the tread portion 10 of the tire 1 based on at least one of the pitch 31 and the block 32. The evaluation section 41 includes a friction energy measurement target portion of the tire 1, a heel and toe wear prediction target portion of the tire 1, and a heel and toe wear evaluation target portion of the tire 1.

  In the example shown in FIG. 7, the evaluation section 41 may be defined by one pitch 31. The evaluation section 41 may be defined by one block 32.

  In the example shown in FIG. 8, the evaluation section 41 may be defined by one pitch 31. The evaluation section 41 may be defined by the block 32A. The evaluation section 41 may be defined by the block 32B. The evaluation section 41 may be defined by the block 32C. The evaluation section 41 may be defined by the block 32D.

  The evaluation section 41 may be defined based on at least one of the lug groove 22 and the sipe 23. The evaluation section 41 may be partitioned by two lug grooves 22 that are adjacent to each other in the circumferential direction of the tire 1. The evaluation section 41 may be defined by the lug groove 22 and the sipe 23 that are adjacent to each other in the circumferential direction of the tire 1.

  For example, as shown in FIG. 7, the evaluation section 41 may be defined between the lug groove 22 and the sipe 23 that are adjacent to each other in the circumferential direction of the tire 1.

  For example, as shown in FIG. 8, the evaluation section 41 may be defined between the lug groove 22 </ b> A and the lug groove 22 </ b> B that are adjacent to each other in the circumferential direction of the tire 1. Further, as shown in FIG. 8, the evaluation section 41 may be defined between the lug groove 22 </ b> F and the sipe 23 that are adjacent to each other in the circumferential direction of the tire 1. Further, as shown in FIG. 8, the evaluation section 41 may be defined between the lug groove 22 </ b> G and the sipe 23 that are adjacent to each other in the circumferential direction of the tire 1.

  As shown in FIGS. 7 and 8, a plurality of evaluation sections 41 are defined in the circumferential direction.

  In the present embodiment, a tire 1 is prepared in which a plurality of groove patterns (pitch 31) of the same or similar design as shown in FIG. 7 or 8 are provided in the circumferential direction of the central axis AX (step). SA1). The tire 1 is an evaluation target tire. The tire 1 may be referred to as a test tire 1.

  Next, as described with reference to FIGS. 7 and 8, the evaluation section 41 of the tire 1 is defined based on at least one of the pitch 31 and the block 32 (step SA2). The definition of the evaluation section 41 is performed by the processing device 50.

  Next, the measurement of the friction energy of the measurement part 43A defined in the first arrival part of the evaluation section 41 and the friction energy of the measurement part 43B defined in the rear attachment part of the evaluation section 41 is performed (step SA3). The friction energy is measured using a friction energy tester 57.

  9 to 13 are diagrams schematically illustrating an example of the evaluation section 41, the measurement site 43A, and the measurement site 43B.

  FIG. 9 shows an example in which the evaluation section 41 is defined between two lug grooves 22 adjacent in the circumferential direction of the tire 1. In the example shown in FIG. 9, no other groove exists between the two lug grooves 22 in the circumferential direction. In FIG. 9, the region between the two lug grooves 22 may be regarded as the pitch 31 or the block 32.

  The measurement site 43A is defined at one end of the evaluation section 41 or in the vicinity thereof in the circumferential direction. The measurement site 43B is defined at the other end of the evaluation section 41 or in the vicinity thereof in the circumferential direction.

  When the tire 1 is mounted on a vehicle and travels, one end portion of the evaluation section 41 contacts the road surface before the other end portion in the circumferential direction. The first landing portion refers to a portion of the evaluation section 41 that comes into contact with the road surface first when the tire 1 travels on the road surface while rotating about the central axis AX. The rear landing portion refers to a portion of the evaluation section 41 that contacts the road surface later when the tire 1 travels on the road surface while rotating about the central axis AX. In the present embodiment, one end portion of the evaluation section 41 is the first arrival portion with respect to the circumferential direction. With respect to the circumferential direction, the other end of the evaluation section 41 is a rear arrival part.

  In the example shown in FIG. 9, the measurement site 43 </ b> A is determined at the first arrival part of the evaluation section 41 or in the vicinity thereof. The measurement site 43B is determined at the rear part of the evaluation section 41 or in the vicinity thereof.

  FIG. 10 shows an example in which the evaluation section 41 is defined between two lug grooves 22 arranged in the circumferential direction of the tire 1. In the example shown in FIG. 10, the sipe 23 is disposed between the two lug grooves 22 in the circumferential direction. In FIG. 10, a region between two lug grooves 22 may be regarded as a pitch 31 or a block 32.

  Also in the example shown in FIG. 10, the measurement site 43 </ b> A is determined at the first arrival part of the evaluation section 41 or in the vicinity thereof. The measurement site 43B is determined at the rear part of the evaluation section 41 or in the vicinity thereof.

  FIG. 11 shows an example in which the evaluation section 41 is defined between two lug grooves 22 arranged in the circumferential direction of the tire 1. In the example shown in FIG. 11, one other lug groove 22 (222) is arranged between two lug grooves 22 (221) defining the evaluation section 41 in the circumferential direction. In FIG. 11, the area between the two lug grooves 22 (221) defining the evaluation section 41 may be regarded as the pitch 31.

  Also in the example shown in FIG. 11, the measurement site 43 </ b> A is determined at the first arrival part of the evaluation section 41 or in the vicinity thereof. The measurement site 43B is determined at the rear part of the evaluation section 41 or in the vicinity thereof.

  FIG. 12 shows an example in which the evaluation section 41 is defined between two sipes 23 arranged in the circumferential direction of the tire 1. In the example shown in FIG. 12, one other sipe 23 (232) is arranged between two sipes 23 (231) that define the evaluation section 41 in the circumferential direction. In FIG. 12, the area between the two sipes 23 (231) that define the evaluation section 41 may be regarded as the pitch 31.

  Also in the example illustrated in FIG. 12, the measurement site 43 </ b> A is determined at the first arrival part of the evaluation section 41 or in the vicinity thereof. The measurement site 43B is determined at the rear part of the evaluation section 41 or in the vicinity thereof.

  FIG. 13 shows an example in which the evaluation section 41 is defined between two sipes 23 arranged in the circumferential direction of the tire 1. In the example illustrated in FIG. 13, two other sipes 23 (234) are arranged between two sipes 23 (233) that define the evaluation section 41 in the circumferential direction. In FIG. 13, the area between the two sipes 23 (233) that define the evaluation section 41 may be regarded as the pitch 31.

  Also in the example shown in FIG. 13, the measurement site 43 </ b> A is determined at the first arrival part of the evaluation section 41 or in the vicinity thereof. The measurement site 43B is determined at the rear part of the evaluation section 41 or in the vicinity thereof.

  In the above-described embodiment, the dimension of the evaluation section 41 in the circumferential direction is preferably ¼ or less of the dimension of the entire circumference of the tire 1.

  FIG. 14 is a schematic diagram in which the measurement site 43A and the measurement site 43B defined in the circumferential direction in the evaluation zone 41 and the evaluation zone 41 are generalized. FIG. 14 is a plan view of the evaluation section 41. The frictional energy tester 57 measures the frictional energy of the measurement part 43 </ b> A determined in the first arrival part 44 of the evaluation section 41 and the frictional energy of the measurement part 43 </ b> B determined in the rearward part 45 of the evaluation section 41.

  After the friction energy of the measurement site 43 </ b> A and the friction energy of the measurement site 43 </ b> B are measured by the friction energy tester 57, the measurement results are output to the processing device 50. The calculation unit 51 of the processing unit 50p of the processing device 50 derives a difference in magnitude between the friction energy of the measurement site 43A and the friction energy of the measurement site 43B (step SA4). In the present embodiment, the difference between the measured frictional energy of the measurement site 43A and the frictional energy of the measurement site 43B is derived.

  Based on the difference between the friction energy of the measurement region 43A and the friction energy of the measurement region 43B, the heel and toe wear of the tire 1 in the evaluation section 41 is predicted (step SA5). The prediction of heel and toe wear is performed by the processing device 50.

  FIG. 15 is a diagram schematically illustrating an example of a prediction result of heel and toe wear in the evaluation section 41. FIG. 15 is a side sectional view of a part of the tire 1 in the evaluation section 41. FIG. 15 shows a cross section of the tire 1 in a plane (XZ plane) orthogonal to the central axis AX.

  The heel and toe wear means that the land portion (evaluation section 41) surrounded by the groove 20 is worn unevenly with respect to the circumferential direction (traveling direction, rotational direction) of the tire 1. If heel and toe wear occurs, a step may occur in the evaluation section 41. The heel and toe wear occurs due to the difference between the friction energy of the first attaching portion 44 of the evaluation section 41 and the friction energy of the rear attaching portion 45.

  The level difference of the evaluation section 41 refers to the difference between the distance between the central axis AX and the first arrival part 44 and the distance between the central axis AX and the rear arrival part 45 with respect to the radial direction with respect to the central axis AX. In other words, the level difference of the evaluation section 41 refers to the difference between the height of the first arrival part 44 and the height of the rear arrival part 45. The step amount of the evaluation section 41 refers to the value of the step of the evaluation section 41.

  If the difference between the friction energy of the first arrival part 44 in the evaluation section 41 and the friction energy of the rear attachment part 45 is large, the level difference (level difference) in the evaluation section 41 increases. If the difference between the frictional energy of the first arrival part 44 and the frictional energy of the rear attachment part 45 in the evaluation section 41 is small, the level difference (level difference) in the evaluation section 41 becomes small.

  Therefore, the friction energy of the measurement part 43A defined in the first arrival part 44 of the evaluation section 41 is measured, the friction energy of the measurement part 43B defined in the rear attachment part 45 of the evaluation section 41 is measured, and the friction of the measurement part 43A. By deriving the difference between the energy and the friction energy of the measurement site 43B, the heel and toe wear of the test tire 1 in the evaluation section 41 is predicted with high accuracy.

  As described above, according to the present embodiment, the evaluation section 41 of the tire 1 is defined based on at least one of the pitch 31 and the block 32, and the frictional energy of the measurement site 43A of the first landing portion 44 of the evaluation section 41 is determined. By measuring the friction energy of the measurement site 43B of the rear attachment 45, the prediction accuracy of the heel and toe wear of the tire 1 in the evaluation section 41 can be improved based on the measurement result.

  In the present embodiment, a plurality of evaluation sections 41 are defined in the circumferential direction of the tire 1. For each of the plurality of evaluation sections 41, the friction energy of the measurement site 43A and the friction energy of the measurement site 43B are measured. The processing device 50 predicts heel and toe wear based on the difference between the friction energy of the measurement site 43A and the friction energy of the measurement site 43B, which is derived for each of the plurality of evaluation sections 41. Thereby, the heel and toe wear which generate | occur | produces in each of the some evaluation division 41 can be estimated and evaluated. For example, wear can be predicted for each of a plurality of evaluation sections 41 adjacent in the circumferential direction. Further, it is possible to predict the step shape of the evaluation section 41 caused by the heel and toe wear, predict the step amount of the evaluation section 41, and predict the irregular heel and toe wear form for each evaluation section 41. .

  In the above-described embodiment, the measurement site 43A is defined as the first arrival part 44 and the measurement site 43B is defined as the rear arrival part 45. As shown in FIG. 16, the measurement site 43 </ b> A may be defined in a first arrival area 48 including the first arrival portion 44. The measurement site 43 </ b> B may be defined in a later arrival area 49 including the later arrival part 45.

  FIG. 16 is a diagram schematically illustrating an example of the evaluation section 41. As shown in FIG. 16, the first arrival region 48 is defined between a first arrival portion 44 that is one end portion of the evaluation section 41 in the circumferential direction and a portion 46 that is closer to the center of the evaluation section 41 than the first arrival section 44 in the circumferential direction. Is done. The rear arrival area 49 is defined between a rear arrival portion 45 that is the other end portion of the evaluation section 41 in the circumferential direction and a portion 47 that is closer to the center of the evaluation section 41 than the rear arrival section 45 in the circumferential direction. The measurement site 43 </ b> A may be defined in a first arrival region 48 between the first arrival part 44 and the site 46 in the circumferential direction. The measurement site 43 </ b> B may be defined in a later-attachment region 49 between the rear-attachment 45 and the site 47 in the circumferential direction.

  With respect to the circumferential direction, the distance between the first arrival part 44 and the part 46 and the distance between the rear arrival part 45 and the part 47 are respectively 1/3 or less of the distance H between the first arrival part 44 and the rear arrival part 45 in the evaluation section 41. Determined. The distance between the first arrival part 44 and the part 46 and the distance between the rear arrival part 45 and the part 47 are preferably set to 20% or less of the distance H between the first arrival part 44 and the rear arrival part 45 in the evaluation section 41, respectively. . The distance between the first arrival part 44 and the part 46 is the dimension of the first arrival region 48 in the circumferential direction. The distance between the rear wearing part 45 and the part 47 is the dimension of the rear wearing region 49 in the circumferential direction.

  The first arrival area 48 includes the first arrival portion 44 of the evaluation section 41. The rear arrival area 49 includes a rear arrival portion 45 of the evaluation section 41. When the measurement site 43A is defined in the first arrival area 48 and the measurement site 43B is defined in the second arrival area 49, the friction in the first arrival portion 44 or the vicinity thereof in the evaluation section 41 and the rear arrival section 45 or the vicinity thereof in the evaluation section 41 Energy can be measured. The heel and toe wear occurs due to the difference between the friction energy of the first attaching portion 44 of the evaluation section 41 and the friction energy of the rear attaching portion 45. Therefore, by defining the measurement site 43A as the first arrival region 48 including the first arrival portion 44 of the evaluation section 41 or the vicinity thereof, and determining the measurement portion 43B as the rear arrival region 49 including the first arrival portion 45 of the evaluation section 41 or the vicinity thereof, The form of heel and toe wear can be accurately predicted.

  Further, the frictional energy is measured while avoiding the central portion of the evaluation section 41 with respect to the circumferential direction, thereby suppressing the heel and toe wear from being underestimated.

  In the above-described embodiment, the positions of the measurement site 43 </ b> A and the measurement site 43 </ b> B are substantially the same in the width direction of the tire 1. As shown in FIG. 17, the positions of the measurement site 43A and the measurement site 43B may be different in the width direction. When the measurement site 43A and the measurement site 43B are different in the width direction, the distance between the measurement site 43A and the measurement site 43B in the Y-axis direction is preferably 5 mm or less. The same applies to the following embodiments.

Second Embodiment
A second embodiment will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  In the present embodiment, a plurality of evaluation sections 41 are defined in the circumferential direction of the tire 1, and the friction energy of the measurement site 43 </ b> A and the measurement site 43 </ b> B is measured for each of the plurality of evaluation sections 41. An example in which heel and toe wear is predicted based on the difference in friction energy derived from the above will be described.

  FIG. 18 is a side view schematically showing an example of the tire 1 according to the present embodiment. As shown in FIG. 18, the tire 1 has a plurality of blocks 32 in the circumferential direction. In the example illustrated in FIG. 18, the block 32 of the tire 1 includes a block 321, a block 322, a block 323, a block 324, a block 325, a block 326, a block 327, a block 328, a block 329, a block 3210, which are arranged in the circumferential direction. A block 3211 and a block 3212 are included. That is, in this embodiment, there are 12 blocks 32.

  In the present embodiment, the evaluation section 41 includes an evaluation section 41A, an evaluation section 41B, an evaluation section 41C, and an evaluation section 41D that are arranged in the circumferential direction. That is, in this embodiment, four evaluation sections 41 are defined in the circumferential direction.

  In the example illustrated in FIG. 18, the evaluation section 41A is defined by a block 321, the evaluation section 41B is defined by a block 324, the evaluation section 41C is defined by a block 327, and the evaluation section 41D is defined by a block 3210.

  A measurement site 43A and a measurement site 43B are defined in each of the plurality of evaluation sections 41 (41A, 41B, 41C, 41D). For each of the plurality of evaluation sections 41 (41A, 41B, 41C, 41D), the frictional energy of the measurement site 43A and the measurement site 43B is measured.

  For each of the plurality of evaluation sections 41 (41A, 41B, 41C, 41D), the difference between the friction energy of the measurement site 43A and the friction energy of the measurement site 43B is derived. In the present embodiment, the processing device 50 calculates a difference D1 between the friction energy of the measurement site 43A of the evaluation section 41A and the friction energy of the measurement site 43B based on the measurement result of the friction energy tester 57. Based on the measurement result of the friction energy tester 57, the processing device 50 calculates the difference D2 between the friction energy of the measurement site 43A of the evaluation section 41B and the friction energy of the measurement site 43B. Based on the measurement result of the friction energy tester 57, the processing device 50 calculates the difference D3 between the friction energy of the measurement site 43A and the friction energy of the measurement site 43B in the evaluation section 41C. Based on the measurement result of the friction energy tester 57, the processing device 50 calculates the difference D4 between the friction energy of the measurement site 43A of the evaluation section 41D and the friction energy of the measurement site 43B.

  The processing device 50 predicts heel and toe wear based on the friction energy differences D1, D2, D3, and D4 derived for each of the plurality of evaluation sections 41 (41A, 41B, 41C, and 41D).

  For example, the processing device 50 may calculate an average value aveD of the difference D1, the difference D2, the difference D3, and the difference D4, and predict the heel and toe wear based on the average value aveD. By using the average value aveD, an average step amount of the tire 1 in the circumferential direction can be predicted.

  The processing device 50 may derive the maximum values of the difference D1, the difference D2, the difference D3, and the difference D4, and predict the heel and toe wear based on the maximum values. By using the maximum value, the maximum value of the step amount of the tire 1 in the circumferential direction can be predicted.

  The processing device 50 may derive the maximum value and the minimum value of the difference D1, the difference D2, the difference D3, and the difference D4, and predict the heel and toe wear based on the difference between the maximum value and the minimum value. By using the difference between the maximum value and the minimum value, it is possible to predict the variation in the step amount of the tire 1 in the circumferential direction.

  As described above, according to the present embodiment, a plurality of evaluation sections 41 are defined in the circumferential direction of the tire 1, the frictional energy of the measurement site 43 is measured for each of the plurality of evaluation sections 41, and a plurality of evaluation sections are measured. Based on the frictional energy differences (D1, D2, D3, and D4) derived for each of the tires 41, the heel and toe wear is predicted to occur in each of the evaluation sections 41 that are defined in the circumferential direction in the tire 1. Heel and toe wear can be accurately predicted and evaluated.

  According to this embodiment, wear can be predicted for each of a plurality of evaluation sections 41 adjacent in the circumferential direction. Further, it is possible to predict the step shape of the evaluation section 41 caused by the heel and toe wear, predict the step amount of the evaluation section 41, and predict the irregular heel and toe wear form for each evaluation section 41. . Further, the overall tendency of heel and toe wear occurring in the tire 1 can be predicted.

  Further, according to the present embodiment, such as uneven wear that occurs in the circumferential direction due to the distributed design of the dimensions of the block 32 in the circumferential direction, local uneven wear that occurs locally in a specific part, and polygonal wear Irregular heel and toe wear morphology can be predicted and evaluated.

  In the present embodiment, twelve blocks 32 exist. Of course, twelve or more blocks 32 may exist. In the present embodiment, four evaluation sections 41 are defined. Of course, the evaluation section 41 is not limited to four. For example, the number of evaluation sections 41 may be 2 or more and 20 or less. The number of evaluation sections 41 is preferably 4 or more and 12 or less.

<Third Embodiment>
A third embodiment will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  In the present embodiment, an example in which the evaluation section 41 includes a plurality of evaluation sections 41 having different dimensions in the circumferential direction will be described. That is, an example in which at least two types of dimensions of the evaluation section 41 are determined in the circumferential direction will be described.

  FIG. 19 is a side view schematically showing an example of the tire 1 according to the present embodiment. As shown in FIG. 19, the tire 1 has a plurality of blocks 32 arranged in the circumferential direction. In the example illustrated in FIG. 19, the block 32 of the tire 1 includes a block 32La having a dimension La, a block 32Lb having a dimension Lb, and a block 32Lc having a dimension Lc with respect to the circumferential direction of the central axis AX.

  The dimension La, the dimension Lb, and the dimension Lc are different. In the present embodiment, among the dimensions La, Lb, and Lc, the dimension La is the largest, the dimension Lb is the second largest after the dimension La, and the dimension Lc is the smallest.

  As shown in FIG. 19, there are three blocks 32La. There are six blocks 32Lb. There are three blocks 32Lc. That is, in this embodiment, there are 12 blocks 32.

  In the present embodiment, the evaluation section 41 includes an evaluation section 41A, an evaluation section 41B, an evaluation section 41C, and an evaluation section 41D that are arranged in the circumferential direction. That is, in this embodiment, four evaluation sections 41 are defined in the circumferential direction.

  In the example shown in FIG. 19, the evaluation section 41A is defined by the block 32La, the evaluation section 41B is defined by the block 32Lb, the evaluation section 41C is defined by the block 32Lc, and the evaluation section 41D is defined by the block 32Lb.

  At least one of the block 32La, the block 32Lb, and the block 32Lc may have the sipe 23.

  A measurement site 43A and a measurement site 43B are defined in each of the plurality of evaluation sections 41 (41A, 41B, 41C, 41D). For each of the plurality of evaluation sections 41 (41A, 41B, 41C, 41D), the frictional energy of the measurement site 43A and the measurement site 43B is measured.

  For each of the plurality of evaluation sections 41 (41A, 41B, 41C, 41D), the difference between the friction energy of the measurement site 43A and the friction energy of the measurement site 43B is derived. In the present embodiment, the processing device 50 calculates a difference D1 between the friction energy of the measurement site 43A of the evaluation section 41A and the friction energy of the measurement site 43B based on the measurement result of the friction energy tester 57. Based on the measurement result of the friction energy tester 57, the processing device 50 calculates the difference D2 between the friction energy of the measurement site 43A of the evaluation section 41B and the friction energy of the measurement site 43B. Based on the measurement result of the friction energy tester 57, the processing device 50 calculates the difference D3 between the friction energy of the measurement site 43A and the friction energy of the measurement site 43B in the evaluation section 41C. Based on the measurement result of the friction energy tester 57, the processing device 50 calculates the difference D4 between the friction energy of the measurement site 43A of the evaluation section 41D and the friction energy of the measurement site 43B.

  The processing device 50 predicts heel and toe wear based on the friction energy differences D1, D2, D3, and D4 derived for each of the plurality of evaluation sections 41 (41A, 41B, 41C, and 41D).

  For example, the processing device 50 may calculate an average value aveD of the difference D1, the difference D2, the difference D3, and the difference D4, and predict the heel and toe wear based on the average value aveD. By using the average value aveD, an average step amount of the tire 1 in the circumferential direction can be predicted.

  The processing device 50 may derive the maximum values of the difference D1, the difference D2, the difference D3, and the difference D4, and predict the heel and toe wear based on the maximum values. By using the maximum value, the maximum value of the step amount of the tire 1 in the circumferential direction can be predicted.

  The processing device 50 may derive the maximum value and the minimum value of the difference D1, the difference D2, the difference D3, and the difference D4, and predict the heel and toe wear based on the difference between the maximum value and the minimum value. By using the difference between the maximum value and the minimum value, it is possible to predict the variation in the step amount of the tire 1 in the circumferential direction.

  As described above, according to the present embodiment, since the plurality of evaluation sections 41 are defined so that the dimensions are different in the circumferential direction of the central axis AX, the heel and toe wear of each evaluation section 41 according to the dimensions in the circumferential direction is determined. The form can be predicted. Further, the overall tendency of heel and toe wear occurring in the tire 1 can be predicted.

  Further, according to the present embodiment, such as uneven wear that occurs in the circumferential direction due to the distributed design of the dimensions of the block 32 in the circumferential direction, local uneven wear that occurs locally in a specific part, and polygonal wear Irregular heel and toe wear morphology can be predicted and evaluated.

  In the present embodiment, an evaluation section 41A having the largest dimension La, an evaluation section 41B and evaluation section 41D having the second largest dimension Lb after the dimension La, and an evaluation section 41C having the smallest dimension Lc are defined.

  By measuring the friction energy for the evaluation section 41A having the largest dimension La, the heel and toe wear due to the strength of the grounding restraint of the block 32La can be predicted.

  By measuring the friction energy for the evaluation section 41C having the smallest dimension Lc, the heel and toe wear due to the collapse of the block 32Lc can be predicted.

  By measuring the friction energy for the evaluation section 41B and the evaluation section 41D having the dimension Lb between the dimension La and the dimension Lc, typical heel and toe wear of the tire 1 can be predicted.

  In this embodiment, three types (three levels) of different evaluation sections 41 (La, Lb, Lc) in the circumferential direction are defined. In the present embodiment, it is only necessary to define at least two types (two levels) of evaluation sections 41 having different dimensions in the circumferential direction. That is, the evaluation section 41 may include a first evaluation section 41 having a first dimension in the circumferential direction and a second evaluation section 41 having a second dimension different from the first dimension. Of course, an evaluation section 41 having dimensions of an arbitrary number of levels of four types (four levels) or more may be defined.

<Fourth embodiment>
A fourth embodiment will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  FIG. 20 is a plan view schematically showing an example of the evaluation section 41 according to the present embodiment. FIG. 21 is a flowchart illustrating an example of a method for predicting wear of the tire 1 according to the present embodiment.

  Similar to the above-described embodiment, the tire 1 is prepared (step SB1), and the evaluation section 41 is defined (step SB2).

  As shown in FIG. 20, the measurement site 43 </ b> A is defined in the first arrival part 44. A measurement site 43B is defined in the rear attachment 45. In the present embodiment, the measurement site 43C is defined between the measurement site 43A and the measurement site 43B in the circumferential direction (step SB3). In the present embodiment, the measurement site 43C is defined at the center of the measurement site 43A and the measurement site 43B in the circumferential direction.

  The friction energy of the measurement site 43A, the friction energy of the measurement site 43B, and the friction energy of the measurement site 43C are measured by the friction energy tester 57 (step SB4).

  One of the measurement site 43A and the measurement site 43B is set as a reference site (step SB5). In the present embodiment, the measurement site 43A is set as the reference site.

  The processing device 50 calculates the difference (first difference) R between the friction energy of the reference part (measurement part) 43A and the friction energy of the measurement part 43B (step SB6). The processing device 50 determines the calculated difference R as a reference value.

  In the present embodiment, the difference R is a ratio between the friction energy of the reference portion 43A and the friction energy of the measurement portion 43B. The difference R may be a difference between the friction energy of the reference portion 43A and the friction energy of the measurement portion 43B.

  The processing device 50 calculates a difference (second difference) R1 between the friction energy of the reference portion 43A and the friction energy of the measurement portion 43C (step SB7).

  In the present embodiment, the difference R1 is a ratio between the friction energy of the reference portion 43A and the friction energy of the measurement portion 43C. The difference R1 may be a difference between the friction energy of the reference portion 43A and the friction energy of the measurement portion 43C.

  The processing device 50 predicts the heel and toe wear of the tire 1 in the evaluation section 41 based on the calculated difference R and difference R1 (step SB8).

  FIG. 22 is a diagram schematically illustrating an example of a prediction result of heel and toe wear in the evaluation section 41 according to the present embodiment. FIG. 22 shows a side sectional view of a part of the tire 1 in the evaluation section 41.

  As shown in FIG. 22, the measurement part 43A is set as a reference part, the difference R between the frictional energy of the reference part 43A and the frictional energy of the measurement part 43B is calculated, and the difference R is used as a reference value. By comparing the ratio R1 between the frictional energy and the frictional energy of the measurement part 43C, the step amount between the reference part 43A and the measurement part 43C can be predicted on the basis of the step amount between the reference part 43A and the measurement part 43B. it can. Thereby, the shape of the evaluation section 41 which changes with heel and toe wear can be accurately predicted.

  In the present embodiment, the distance between the measurement site 43C and the measurement site 43A and the distance between the measurement site 43C and the measurement site 43B are equal in the circumferential direction. Regarding the circumferential direction, the distance between the measurement site 43C and the measurement site 43A and the distance between the measurement site 43C and the measurement site 43B may be different.

  In the present embodiment, a plurality of measurement sites 43C may be defined between the measurement site 43A and the measurement site 43B.

  In the present embodiment, the measurement site 43A is set as the reference site. Of course, the measurement site 43B may be set as the reference site. In this case, the difference R is a difference (ratio or difference) between the reference part (measurement part) 43B and the measurement part 43A. The difference R1 is a difference (ratio or difference) between the reference portion 43B and the measurement portion 43C.

<Fifth Embodiment>
A fifth embodiment will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  FIG. 23 is a plan view showing a part of the tread portion 10 of the tire 1 according to the present embodiment. In the present embodiment, an example will be described in which at least two or more lane regions 60 having a predetermined width in the direction parallel to the central axis AX are set, and the measurement site 43 is determined in each of the plurality of lane regions 60.

  As shown in FIG. 23, in the present embodiment, a plurality of lane regions 60 having a predetermined width LW in the width direction (a direction parallel to the central axis AX) are set in the width direction. A measurement site 43A and a measurement site 43B are defined in each of the plurality of lane regions 60.

  In the example shown in FIG. 23, the lane region 60 includes a first lane region 61 and a second lane region 62 set at a position different from the first lane region 61 in the width direction.

  The dimension LW of the first lane region 61 in the width direction is equal to the dimension LW of the second lane region 62 in the width direction. In the present embodiment, the dimension LW is set to 5 mm or less.

  The first lane region 61 is set in the −Y side shoulder portion 12. The second lane region 62 is set in the shoulder portion 12 on the + Y side.

  The measurement site 43A and the measurement site 43B are defined in the first lane region 61 and the second lane region 62, respectively. In the evaluation section 41 of the first lane region 61, a measurement site 43A and a measurement site 43B are defined. Based on the difference between the friction energy of the measurement region 43A in the first lane region 61 and the friction energy of the measurement region 43B, the heel and toe wear of the tire 1 in the first lane region 61 is predicted.

  Similarly, in the evaluation section 41 of the second lane region 62, the measurement site 43A and the measurement site 43B are determined. The heel and toe wear of the tire 1 in the second lane region 62 is predicted based on the difference between the friction energy of the measurement region 43A in the second lane region 62 and the friction energy of the measurement region 43B.

  In the present embodiment, the processing device 50 calculates the difference D1 between the friction energy of the measurement site 43A and the friction energy of the measurement site 43B in the first lane region 61 based on the measurement result of the friction energy tester 57. Based on the measurement result of the friction energy tester 57, the processing device 50 calculates the difference D2 between the friction energy of the measurement site 43A and the friction energy of the measurement site 43B in the second lane region 62.

  In the first lane region 61, a plurality of measurement sites 43A and measurement sites 43B are defined. In the first lane region 61, a plurality of differences D1 are calculated. Similarly, in the second lane region 62, a plurality of measurement sites 43A and measurement sites 43B are defined. In the second lane region 62, a plurality of differences D2 are calculated.

  The processing device 50 predicts heel and toe wear based on the friction energy difference D1 and difference D2 derived for each of the plurality of lane regions 60 (61, 62).

  The processing device 50 calculates the difference D1 indicating the maximum value among the plurality of differences D1 calculated for the first lane region 61, and predicts the heel and toe wear in the first lane region 61 based on the maximum value. Also good.

  The processing device 50 calculates a difference D2 indicating a maximum value among the plurality of differences D2 calculated for the second lane region 62, and predicts heel and toe wear in the second lane region 62 based on the maximum value. Also good.

  The processing device 50 may calculate the maximum value of the plurality of differences D1 and the maximum value of the plurality of differences D2, and predict heel and toe wear in the tire 1 based on the maximum values. By using the maximum value, the maximum value of the step amount in the width direction in the tire 1 can be predicted.

  The processing device 50 may calculate an average value of the plurality of differences D1 and an average value of the plurality of differences D2, and predict heel and toe wear based on the average values.

  The processing device 50 may calculate an average value of the plurality of differences D1 and the plurality of differences D2, and may predict heel and toe wear based on the average values. By using the average value, an average step amount in the width direction of the tire 1 can be predicted.

  The processing device 50 calculates the difference between the difference D1 indicating the maximum value and the difference D1 indicating the minimum value among the plurality of differences D1 calculated for the first lane region 61, and based on the difference, the first lane Heel and toe wear in region 61 may be predicted.

  The processing device 50 calculates the difference between the difference D2 indicating the maximum value and the difference D2 indicating the minimum value among the plurality of differences D2 calculated for the second lane region 62, and based on the difference, the second lane Heel and toe wear in region 62 may be predicted.

  The processing device 50 may calculate the difference between the difference D1 indicating the maximum value and the difference D2 indicating the minimum value, and predict the heel and toe wear in the tire 1 based on the difference. By using the difference, it is possible to predict the variation in the step amount in the width direction in the tire 1.

  As described above, according to the present embodiment, the plurality of lane regions 60 are set in the width direction of the tire 1, and the measurement site 43 is defined in each of the lane regions 60. For tires 1 having different radii (so-called tires 1 having a left-right asymmetric pattern), it is possible to accurately predict the form of heel and toe wear according to the groove patterns.

  In the tire 1 having the left-right asymmetric pattern, there is a high possibility that the wear energy is different between the shoulder portion 12 on the left side (−Y side) and the shoulder portion 12 on the right side (+ Y side) of the tire 1. By setting the first lane region 61 to the left shoulder portion 12 and the second lane region 62 to the right shoulder portion 12, in the tire 1 having a left-right asymmetric pattern, the difference in friction energy between the left and right is taken into account. The heel and toe wear of the left shoulder portion 12 of the tire 1 and the heel and toe wear of the right shoulder portion 12 of the tire 1 can be accurately predicted.

  The tire 1 is not limited to the tire 1 having a left-right asymmetric pattern. Even in the tire 1 having the symmetrical pattern, the friction energy may be different in the width direction of the tire 1. Therefore, by setting a plurality of lane regions 60 in the width direction and measuring the friction energy of the measurement parts 43 determined in each of the lane regions 60, the difference in the friction energy in the width direction is taken into account, and the tire 1 Heel and toe wear can be accurately predicted.

  In the present embodiment, the lane region 60 (61, 62) is set in the shoulder portion 12. The lane region 60 may be set in the center portion 11.

  In the present embodiment, the lane region 60 includes the first lane region 61 and the second lane region 62. The number of lane regions 60 in the width direction is not limited to two and may be any number of three or more. For example, as shown in FIG. 24, five lane regions 60 may be provided, and the measurement site 43 </ b> A and the measurement site 43 </ b> B may be defined in each of the lane regions 60.

  In FIG. 24, the tire 1 includes a plurality of sipes 23 not only in the shoulder portion 12 but also in the center portion 11. In the case of the tire 1 as shown in FIG. 24, not only the land portion of the shoulder portion 12 but also the land portion of the center portion 11 is liable to cause heel and toe wear due to falling. Therefore, the difference D1, the difference D2, the difference D3, the difference D4, and the difference D5 between the frictional energy of the measurement part 43A and the frictional energy of the measurement part 43B in each of the five lane regions 60 are calculated. D1, D2, D3, D4, D5) can be used to accurately predict heel and toe wear in each lane region 60.

  For example, by calculating the maximum values of the difference D1, the difference D2, the difference D3, the difference D4, and the difference D5, the maximum value of the step amount in the width direction in the tire 1 can be predicted using the maximum value. it can. Moreover, by calculating the average value of the difference D1, the difference D2, the difference D3, the difference D4, and the difference D5, the average step amount of the tire 1 can be predicted using the average value. Further, the difference between the difference D1, the difference D2, the difference D3, the difference D4, and the difference D5 is calculated as a difference indicating the maximum value (for example, the difference D1) and a difference indicating the minimum value (for example, the difference D5). Thus, using the difference, it is possible to predict the variation in the step amount in the width direction in the tire 1.

<Sixth Embodiment>
A sixth embodiment will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  FIG. 25 is a plan view showing a part of the tread portion 10 of the tire 1 according to the present embodiment. As shown in FIG. 25, in the present embodiment, a portion 71A at one end (−Y side end) of the tread development width TDW of the tire 1 and a portion 71B on the equator plane CL side of the tire 1 with respect to the portion 71A The measurement region 43A and the measurement region 43B are defined in the first region 71 between the two regions. In the present embodiment, the second portion 72A between the other end portion (+ Y side end portion) of the tread development width TDW of the tire 1 and the portion 72B closer to the equator plane CL of the tire 1 than the portion 72A. In the region 72, the measurement site 43A and the measurement site 43B are defined.

  With respect to the width direction of tire 1 (direction parallel to central axis AX), the distance between portion 71A and portion 71B and the distance between portion 72A and portion 72B are each set to 30% or less of tread deployment width TDW. The distance between the part 71A and the part 71B is the dimension (width) of the first region 71 in the Y-axis direction. The distance between the portion 72A and the portion 72B is the dimension (width) of the second region 72 in the Y-axis direction.

  The first region 71 includes the shoulder portion 12 on the -Y side. The second region 72 includes the shoulder portion 12 on the + Y side. The shoulder portion 12 is a portion where heel and toe wear is likely to occur. The shoulder portion 12 has a large effective radius difference from the center portion 11 and a large amount of slip. Therefore, the shoulder portion 12 is a portion where heel and toe wear is most likely to occur in the width direction. By determining the measurement region 43A and the measurement region 43B in the first region 71 and the second region 72, it is possible to accurately predict the form of heel and toe wear in the shoulder portion 12 of the tire 1, which is a portion where heel and toe wear is likely to occur. Can do.

  The shoulder portion 12 is a portion where heel and toe wear is likely to occur because the effective radius difference from the center portion 11 is large and the amount of slip is large. By setting the width of the first region 71 and the second region 72 to 30% or less of the tread development width TDW, the heel and toe wear performance of the portion where the heel and toe wear is likely to occur can be predicted. In addition, the heel and toe wear performance of the test tire 1 can be predicted accurately and efficiently.

  When the width of the first region 71 and the second region 72 exceeds 30% of the tread development width TDW, the width of the region becomes wide. Therefore, in order to accurately predict the portion where heel and toe wear is likely to occur, the friction energy It is necessary to increase the lane area for measuring the friction, and the man-hour for measuring the friction energy increases.

  In order not to overlook a portion where heel and toe wear is likely to occur, the width of the first region 71 and the second region 72 is preferably 20% or less of the tread development width TDW.

<Seventh embodiment>
A seventh embodiment will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  FIG. 26 is a plan view showing a part of the tread portion 10 of the tire 1 according to this embodiment. FIG. 27 is an enlarged view of a portion B in FIG. As shown in FIGS. 26 and 27, in this embodiment, the measurement site is located in the third region 81 between the ground contact end 81A of the tire 1 and the site 81B on the equator plane CL side of the tire 1 relative to the site 81A. 43A and measurement site 43B are defined. In the present embodiment, the measurement region 43A and the measurement region 43B are located in the fourth region 82 between the region 82A closest to the ground contact end and the region 82B closer to the ground contact end than the region 82A in the main groove 21 of the tire 1. Determined.

  The grounding end means an end portion of the tread grounding width W. 26 and 27, the −Y side ground end among the + Y side ground end and the −Y side ground end of the tread ground width W will be described. The main groove 21 is the main groove 21 closest to the grounding end on the -Y side among the plurality (four) of main grooves 21 arranged in the width direction.

  With respect to the width direction of the tire 1 (direction parallel to the central axis AX), the distance between the part 81A and the part 81B is set to 5 mm or less. With respect to the width direction of the tire 1 (direction parallel to the central axis AX), the distance between the part 82A and the part 82B is set to 10 mm or less. The distance between the part 81A and the part 81B is the dimension (width) of the third region 81 in the Y-axis direction. The distance between the part 82A and the part 82B is the dimension (width) of the fourth region 82 in the Y-axis direction.

  The third region 81 and the fourth region 82 are portions where heel and toe wear is likely to occur. The third region 81 is a portion where the effective radius difference from the center portion 11 is large and heel and toe wear is likely to occur. The fourth region 82 is a portion where the amount of collapse of the block 32 is large and heel and toe wear is likely to occur. By determining the measurement region 43 in the third region 81 and the fourth region 82, it is possible to accurately predict the form of heel and toe wear in a portion where heel and toe wear is likely to occur.

  The shoulder portion 12 is a portion where heel and toe wear is likely to occur because the effective radius difference from the center portion 11 is large and the amount of slip is large. Among them, heel and toe wear is more likely to occur near the ground contact end where the effective radius difference from the center portion 11 is larger and near the main groove 21 where the land portion rigidity is low and the collapse amount is large.

  On the other hand, in order to efficiently and accurately predict the heel and toe wear of the test tire 1, it is effective to perform an evaluation at least at a place where the heel and toe wear is likely to occur. The areas near the ground contact edge and the main groove 21 are places where the heel and toe wear is more likely to occur in the shoulder portion 12. Therefore, by performing evaluation at those places, the test tire 1 can be more accurately and efficiently produced. Heel and toe wear can be predicted.

  In addition, in order to accurately grasp a place where heel and toe wear is likely to occur, it is more preferable that the region near the main groove is evaluated in a region within 5 mm from the main groove.

  In the present embodiment, the main groove 21 closest to the −Y side ground end among the −Y side ground end of the tread ground width W and the plurality of (four) main grooves 21 arranged in the width direction. explained. The same applies to the + Y side grounding end of the tread grounding width W and the main groove 21 closest to the + Y side grounding end among the plural (four) main grooves 21 arranged in the width direction.

<Eighth Embodiment>
An eighth embodiment will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  FIG. 28 is an enlarged view of a part of the tread portion 10 of the tire 1 according to the present embodiment. As shown in FIG. 28, in the present embodiment, the maximum width portion 85 having the maximum width in the lug groove 22 that defines the evaluation section 41 is extracted. The measurement part 43A and the measurement part 43B are defined in a range 86 within 5 mm from the maximum width part 85 of the lug groove 22 with respect to the width direction of the tire 1 (direction parallel to the central axis AX).

  That is, with respect to the width direction, the distance between the end 86A on one side of the range 86 and the maximum width portion 85 is set to 5 mm or less. With respect to the width direction, the distance between the end 86B on the other side of the range 86 and the maximum width portion 85 is set to 5 mm or less.

  The maximum width portion 85 or the vicinity thereof is a portion where discontinuity of grounding is strong and heel and toe wear is likely to occur. By setting the measurement site 43A and the measurement site 43B in the range 86 including the maximum width site 85, it is possible to accurately predict the form of heel and toe wear in a portion where heel and toe wear is likely to occur.

  A place where the width of the lug groove 22 or the width of the sipe 23 is wide is a portion where heel and toe wear is likely to occur because the discontinuity of grounding is strong. It is possible to accurately evaluate the influence of the width of the lug groove 22 or the width of the sipe 23 by evaluating in the region within 5 mm in the width direction from the portion where the width of the lug groove 22 or the width of the sipe 23 is maximum. Become. If the evaluation is performed in an area exceeding 5 mm, it is difficult to accurately evaluate the influence of the width of the lug groove 22 or the width of the sipe 23.

  In addition, in order to grasp the influence of the width of the lug groove 22 or the width of the sipe 23 more accurately, an evaluation is performed in a region within 3 mm in the width direction with respect to a portion where the width of the lug groove 22 or the sipe 23 is the maximum. More preferably.

  In the present embodiment, the maximum width portion 85 of the lug groove 22 that defines the evaluation section 41 has been described. The same applies to the sipe 23 that defines the evaluation section 41. When the evaluation section 41 is defined based on the sipe 23, the maximum width portion 85 having the maximum width in the sipe 23 that defines the evaluation section 41 is extracted. The measurement part 43A and the measurement part 43B are defined in a range 86 within 5 mm from the maximum width part 85 of the sipe 23 with respect to the width direction of the tire 1 (direction parallel to the central axis AX).

<Ninth Embodiment>
A ninth embodiment will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  FIG. 29 is an enlarged view of a part of the tread portion 10 of the tire 1 according to the present embodiment. FIG. 29 is a view in which a cross-sectional view of the lug groove 22 and a cross-sectional view of the tread portion 10 are combined. As shown in FIG. 29, in the present embodiment, the maximum depth portion 87 having the maximum depth in the lug groove 22 that defines the evaluation section 41 is extracted. The measurement site 43A and the measurement site 43B are defined in a range 88 within 5 mm from the maximum depth site 87 of the lug groove 22 with respect to the width direction of the tire 1 (direction parallel to the central axis AX).

  That is, with respect to the width direction, the distance between the end 88A on one side of the range 88 and the maximum depth portion 87 is set to 5 mm or less. With respect to the width direction, the distance between the end 88B on the other side of the range 88 and the maximum depth portion 87 is set to 5 mm or less.

  The maximum depth portion 87 or the vicinity thereof is a portion where the amount of collapse of the land portion is large and heel and toe wear is likely to occur. By determining the measurement site 43A and the measurement site 43B within the range 88 including the maximum depth region 87, it is possible to accurately predict the form of heel and toe wear in a portion where heel and toe wear is likely to occur.

  A place where the lug groove 22 or the sipe 23 is deep is a portion where heel and toe wear is likely to occur because the amount of collapse of the land portion is large. It is possible to accurately evaluate the influence of the depth of the lug groove 22 or the sipe 23 by evaluating in a region within 5 mm in the width direction from the portion where the depth of the lug groove 22 or the sipe 23 is maximum. It becomes. If the evaluation is performed in a region exceeding 5 mm, it is difficult to accurately evaluate the influence of the depth of the lug groove 22 or the depth of the sipe 23.

  In addition, in order to grasp the influence of the depth of the lug groove 22 or the depth of the sipe 23 more accurately, the region where the depth of the lug groove 22 or the sipe 23 is maximum is within a region within 3 mm in the width direction. More preferably, the evaluation is performed.

  In the present embodiment, the maximum depth portion 87 of the lug groove 22 that defines the evaluation section 41 has been described. The same applies to the sipe 23 that defines the evaluation section 41. When the evaluation section 41 is defined based on the sipe 23, the maximum depth portion 87 having the maximum depth in the sipe 23 that defines the evaluation section 41 is extracted. The measurement part 43A and the measurement part 43B are defined in a range 88 within 5 mm from the maximum depth part 87 of the sipe 23 with respect to the width direction of the tire 1 (direction parallel to the central axis AX).

<Tenth Embodiment>
A tenth embodiment will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  FIG. 30 is an enlarged view of a part of the tread portion 10 of the tire 1 according to the present embodiment. As shown in FIG. 30, in the present embodiment, a maximum inclination portion 89 having a maximum inclination angle with respect to the tire width direction is extracted in the lug groove 22 that defines the evaluation section 41. The measurement part 43A and the measurement part 43B are defined in a range 90 within 5 mm from the maximum inclination part 89 of the lug groove 22 in the width direction of the tire 1 (a direction parallel to the central axis AX).

  That is, with respect to the width direction, the distance between the end 90A on one side of the range 90 and the maximum inclined portion 89 is set to 5 mm or less. With respect to the width direction, the distance between the end 90B on the other side of the range 90 and the maximum inclined portion 89 is set to 5 mm or less.

  The maximum inclined portion 89 or the vicinity thereof is a portion where heel and toe wear is likely to occur. By setting the measurement part 43 in the range 90 including the maximum inclination part 89, it is possible to accurately predict the form of heel and toe wear in a part where heel and toe wear is likely to occur.

  The place where the inclination of the lug groove 22 or the inclination of the sipe 23 is large is a portion where heel and toe wear easily occurs. By evaluating in a region within 5 mm in the width direction from the portion where the inclination angle of the lug groove 22 or the sipe 23 is the maximum, it becomes possible to accurately evaluate the influence of the inclination of the lug groove 22 or the sipe 23. If the evaluation is performed in a region exceeding 5 mm, it is difficult to accurately evaluate the influence of the inclination of the lug groove 22 or the sipe 23.

  In order to more accurately grasp the influence of the inclination of the lug groove 22 or the sipe 23, the evaluation is performed in a region within 3 mm in the width direction with respect to the portion where the inclination angle of the lug groove 22 or the sipe 23 is the maximum. It is more preferable.

  In the present embodiment, the maximum inclined portion 89 of the lug groove 22 that defines the evaluation section 41 has been described. The same applies to the sipe 23 that defines the evaluation section 41. When the evaluation section 41 is defined based on the sipe 23, the maximum inclined portion 89 having the maximum inclination angle with respect to the tire width direction is extracted in the sipe 23 that defines the evaluation section 41. The measurement site 43A and the measurement site 43B are defined in a range 90 within 5 mm from the maximum inclination site 89 of the sipe 23 with respect to the width direction of the tire 1 (direction parallel to the central axis AX).

  The inclination angle of the lug groove 22 with respect to the tire width direction includes the inclination angle of the boundary portion between the land portion of the tread portion 10 and the lug groove 22 or the sipe 23 (groove line on the stepping side of the evaluation section 41).

<Eleventh embodiment>
An eleventh embodiment will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  In the present embodiment, a reference value relating to a predetermined frictional energy is compared with the frictional energy of the measurement part 43A and the measurement part 43B of the tire 1, and the heel and toe wear of the tire 1 is predicted based on the comparison result. An example will be described. In the following description, the tire 1 in which heel and toe wear is predicted is appropriately referred to as a test tire 1.

  FIG. 31 is a flowchart illustrating an example of a processing procedure of the method for predicting wear of the test tire 1 according to the present embodiment. As shown in FIG. 31, the method for predicting the wear of the test tire 1 according to this embodiment is a step of preparing a reference tire 1R in which a plurality of groove patterns having the same or similar design are provided in the circumferential direction of the central axis AX ( Step SC1), the step of defining the evaluation section 41 for the reference tire 1R (step SC2), and the measurement region 43A defined in the evaluation section 41 of the reference tire 1R under the same conditions as the measurement of the friction energy of the test tire 1 And a step of measuring the friction energy of the measurement portion 43B (step SC3) and a step of determining a reference value related to the friction energy based on the difference between the friction energy of the measurement portion 43A of the reference tire 1R and the friction energy of the measurement portion 43B. (Step SC4), a step of storing the determined reference value in the storage unit 50m (Step SC5), and a test A step of measuring the friction energy of the measurement site 43A and the measurement site 43B of the ear 1 (step SC6), and a step of comparing the reference value with the friction energy of the measurement site 43A and the measurement site 43B of the test tire 1 (step SC7). And a step of predicting heel and toe wear of the test tire 1 based on the comparison result (step SC8).

  A reference tire (reference tire) 1R is prepared (step SC1). In the present embodiment, the reference tire 1R is a tire having good heel and toe wear in the past market performance. The reference tire 1R may be a tire having poor heel and toe wear in the past market performance.

  The design of the groove pattern of the reference tire 1R may be the same as or similar to that of the test tire 1. The design of the groove pattern of the reference tire 1R may be a design different from that of the test tire 1.

  Similar to the test tire 1, the reference tire 1 </ b> R has a pitch 31 and a block 32. Based on at least one of the pitch 31 and the block 32, the evaluation section 41 of the reference tire 1R is defined (step SC2).

  In the evaluation section 41 of the reference tire 1R, the friction energy of the measurement site 43A and the friction energy of the measurement site 43B are measured using the friction energy tester 57 (step SC3). The measurement of the friction energy of the measurement site 43A and the measurement site 43B of the reference tire 1R is performed under the same conditions as the measurement of the friction energy of the measurement site 43A and the measurement site 43B of the test tire 1.

  Based on the difference between the friction energy of the measurement site 43A and the friction energy of the measurement site 43B of the reference tire 1R, a reference value for the friction energy is determined (step SC4). For example, the difference between the friction energy of the measurement site 43A of the reference tire 1R and the friction energy of the measurement site 43B may be determined as the reference value.

  Further, as will be described later in the embodiment, when the difference between the friction energy of the measurement site 43A and the friction energy of the measurement site 43B includes the ratio of the friction energy of the measurement site 43A and the friction energy of the measurement site 43B, The ratio between the friction energy of the measurement site 43A and the friction energy of the measurement site 43B of the reference tire 1R may be determined as a reference value related to the friction energy.

  The determined reference value is stored in the storage unit 50m (step SC5).

  According to the above-described embodiment, the evaluation section 41 is defined for the test tire 1. The friction energy of the measurement site 43A and the friction energy of the measurement site 43B of the evaluation section 41 are measured using the friction energy tester 57 (step SC6).

  The processing device 50 compares the reference value stored in the storage unit 50m with the frictional energy of the measurement site 43A and the measurement site 43B of the test tire 1 acquired using the friction energy tester 57 (step SC7). .

  The processing device 50 predicts the heel and toe wear of the test tire 1 based on the result of comparison in Step SC7 (Step SC8).

  As described above, according to the present embodiment, the reference value is determined using the reference tire 1R, and the heel and toe wear of the test tire 1 is compared by comparing the reference value with the friction energy of the test tire 1. Predict with high accuracy.

  In the present embodiment, the reference tire 1R is a tire having a specification with good heel and toe wear or a tire having a bad specification depending on past market performance. Based on the past market performance by predicting the heel and toe wear of the test tire 1 with the tires of those specifications as the reference tire 1R and the friction energy data obtained from the reference tire 1R as the reference value Accurate wear performance can be predicted.

  In the present embodiment, the reference tire 1R may be a tire having good heel and toe wear in the vehicle running test. The reference tire 1R may be a tire having poor heel and toe wear in a vehicle running test.

  In the present embodiment, the friction energy of the reference tire 1R and the friction energy of the test tire 1 are compared under the same measurement conditions. The friction energy of the same test tire 1 may be measured under different measurement conditions, and the friction energy measured under these different measurement conditions may be compared.

  For example, the frictional energy of the measurement part defined in the evaluation section of the test tire 1 is measured under each of the reference use condition and the evaluation use condition, and the first measurement part of the test tire measured under the reference use condition is measured. Based on the difference between the friction energy and the friction energy of the second measurement site, determining a reference value for the friction energy, and the reference value and the friction energy of the measurement site of the test tire 1 measured under the evaluation use conditions. Comparing and predicting the heel and toe wear of the test tire 1 under the evaluation use condition based on the comparison result may be performed.

  For example, when the test tire 1 developed for use in the A vehicle is mounted on the B vehicle having a weight different from that of the A vehicle, the use conditions of the test tire 1 when mounted on the A vehicle are the standard use conditions. Yes, the usage condition of the test tire 1 when mounted on the B car is the evaluation usage condition. That is, the reference use condition is a reference measurement condition, and the evaluation use condition is a measurement condition to be evaluated.

  The frictional energy measured when the test tire 1 is mounted on the A car is the frictional energy measured under the standard use conditions. The friction energy measured when the test tire 1 is mounted on the B car is the friction energy measured under the evaluation use conditions.

  When the air pressure is changed for the test tire 1 developed for use in the vehicle A, the use condition of the test tire 1 at the reference air pressure is the reference use condition, and the use condition of the test tire 1 at the evaluation air pressure is the evaluation use condition. It is. The friction energy of the test tire 1 when measured with the reference air pressure is the friction energy measured under the reference use conditions. The friction energy of the test tire 1 when measured with the evaluation air pressure is the friction energy measured under the evaluation use conditions.

  In such a case, even if the reference value related to the friction energy is determined based on the difference between the friction energy of the first measurement site and the friction energy of the second measurement site of the test tire 1 measured under the standard use conditions. Good. The determined reference value is compared with the frictional energy at the measurement site of the test tire 1 measured under the evaluation use condition, and based on the comparison result, the heel and toe wear of the test tire 1 under the evaluation use condition is predicted. May be.

  Thereby, the heel and toe wear of the test tire 1 under the evaluation use condition can be accurately predicted based on the reference value derived from the friction energy measured under the reference use condition using the same test tire 1.

<Twelfth embodiment>
A twelfth embodiment will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  In each of the above-described embodiments, as the difference between the friction energy of the measurement site 43A and the friction energy of the measurement site 43B of the tire 1, a difference in magnitude between the friction energy of the measurement site 43A and the friction energy of the measurement site 43B is used. An example was described. In the present embodiment, an example will be described in which the difference between the friction energy of the measurement site 43A and the friction energy of the measurement site 43B of the tire 1 includes the ratio between the friction energy of the measurement site 43A and the friction energy of the measurement site 43B.

  In order to predict the heel and toe wear, a difference between the friction energy FE1 of the measurement site 43A defined in the first part of the evaluation section 41 and the friction energy FE2 of the measurement site 43B defined in the rear part is derived. As a parameter indicating the difference in magnitude between the frictional energy FE1 and the frictional energy FE2, the difference (FE2-FE1) between the frictional energy FE1 and the frictional energy FE2 may be used, or the frictional energy FE1 and the frictional energy FE2 The ratio (FE2 / FE1) may be used.

  FIG. 32 is a schematic diagram for explaining the characteristics of a method for predicting heel and toe wear using a difference (FE2−FE1) and a method for predicting heel and toe wear using a ratio (FE2 / FE1). FIG. 32 shows an example in which the friction energy is measured for each of the test tire 1A and the test tire 1B.

The frictional energy of the first part of the evaluation section 41 of the test tire 1A measured by the frictional energy tester 57 is 10 [J / m ² ]. The friction energy of the rear part of the evaluation section 41 of the test tire 1 </ ^b > A measured by the friction energy tester 57 is 20 [J / m ² ].

Therefore, the difference between the friction energy of the first arrival part and the friction energy of the rear attachment part of the evaluation section 41 of the test tire 1A is 10 [J / m ² ]. The ratio of the friction energy of the first part and the friction part of the rear part of the evaluation section 41 of the test tire 1A is 2.0.

When the measurement by the frictional energy testing machine 57 is performed on a new test tire 1, the amount of step difference between the first and second arrival parts of the evaluation section 41 of the test tire 1A when the friction energy is measured (new article) This corresponds to an energy difference of 10 [J / m ² ].

When the test tire 1A is mounted on a vehicle and the vehicle travels (actual vehicle travel), the cumulative friction energy of the first landing part when the cumulative friction energy of the rear landing part reaches 50 [J / m ² ] is predicted. The value is expressed by (friction energy of the rear part) / (ratio of the friction energy of the rear part and the friction energy of the first part).

That is, in the test tire 1, when the cumulative friction energy of the rear landing part reaches 50 [J / m ² ], the predicted value of the cumulative friction energy of the first landing part is 25 [J / m ² ].

The difference between the cumulative friction energy at the first landing part and the cumulative friction energy at the rear landing part in the test tire 1A is 25 [J / m ² ]. The amount of step difference between the first part and the last part after the action of the accumulated friction energy corresponds to a friction energy difference of 25 [J / m ² ].

The frictional energy of the first part of the evaluation section 41 of the test tire 1B measured by the frictional energy tester 57 is 40 [J / m ² ]. The friction energy of the rear part of the evaluation section 41 of the test tire 1 </ ^b > B measured by the friction energy tester 57 is 50 [J / m ² ].

Therefore, the difference between the friction energy of the first arrival part and the friction energy of the rear attachment part of the evaluation section 41 of the test tire 1B is 10 [J / m ² ]. The ratio of the frictional energy of the first part and the rear part of the evaluation section 41 of the test tire 1B is 1.25.

The amount of step difference between the first and rear portions of the evaluation section 41 of the test tire 1B when measuring the friction energy (when new) is equivalent to a friction energy difference of 10 [J / m ² ].

That is, the difference (10 [J / m ² ]) between the friction energy of the first and second wear portions of the evaluation section 41 of the test tire 1A when measuring the friction energy (when new) and the test tire 1B. Although the difference (10 [J / m ² ]) between the friction energy of the first arrival part of the evaluation section 41 and the friction energy of the rear arrival part is the same value, the friction of the first arrival part of the evaluation section 41 of the test tire 1A The ratio between the energy and the frictional energy of the rear part (2.0) is different from the ratio of the frictional energy of the first part and the frictional energy of the rear part (1.25) in the evaluation section 41 of the test tire 1B. .

  As described above, in the two tires 1 (the test tire 1A and the test tire 1B), even if the difference between the friction energy of the first arrival part and the friction energy of the rear arrival part is the same value, the friction energy of the first arrival part and the rear arrival part are different. The ratio with the frictional energy of the part may be different. Therefore, not only the difference between the friction energy of the first part and the friction part of the rear part, but also the ratio of the friction energy of the first part and the friction part of the rear part should be taken into account to accurately predict the heel and toe wear. Can do.

  In general, the method using the difference (FE2−FE1) is to calculate the amount of step difference between the first part and the second part when the cumulative frictional energy in actual vehicle travel reaches the frictional energy value measured by the frictional energy tester 57. Excellent to predict. Further, the method using the difference is excellent in predicting the wear form at the time of measuring the friction energy (when new). Further, the method using the difference is excellent in predicting the variation in the step amount of the tire 1 in the circumferential direction.

  In the method using the ratio (FE2 / FE1), when the friction energy exceeding the measured value of the friction energy tester 57 is accumulated in the tire 1 by running the actual vehicle, how much the step amount between the first and second parts is increased. Excellent for predicting how it will progress. In other words, the method using the friction energy ratio is excellent in predicting how much the step amount can grow. For example, when developing a new tire with no market performance, comparing the ratio for the test tire 1 with the ratio for the reference tire 1R as described in the above embodiment, the first arrival part and the rear part in actual vehicle travel It is possible to compare the maximum value of the level difference with the landing portion.

  In the first to eleventh embodiments, the difference between the friction energy of the measurement site 43A and the friction energy of the measurement site 43B of the tire 1 is the difference between the friction energy of the measurement site 43A and the friction energy of the measurement site 43B. The portion processed using the difference in thickness may be processed using the ratio of the friction energy of the measurement site 43A and the friction energy of the measurement site 43B. That is, in each of the above-described embodiments, the portion described as the “difference” in friction energy may be replaced with the “ratio” of the friction energy, and the processing described in each of the above-described embodiments may be performed. The same applies to the following embodiments.

<13th Embodiment>
A thirteenth embodiment will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  FIG. 33 is a schematic diagram for explaining an example of a method for predicting wear of the tire 1 according to the present embodiment. In the present embodiment, the camber angle θ of the tire 1 is set.

  When the tire 1 is actually mounted on the vehicle, it is affected by the alignment. In particular, depending on the setting of the camber angle, there is a high possibility that the ground contact state of the tire 1 is not uniform in the width direction. For example, there is a high possibility that the load (load) acting on the tread portion 10 of the tire 1 becomes non-uniform in the width direction of the tire 1 by setting the camber angle.

  When the load (load) acting on the tread portion 10 of the tire 1 in contact with the ground in the width direction of the tire 1 becomes non-uniform, friction energy becomes non-uniform in the width direction of the tire 1 and uneven wear occurs. There is a high probability that the form of heel and toe wear will be uneven.

  In the present embodiment, according to the setting of the camber angle θ, in the tire 1, the load in contact with the ground is the first portion 93 of the first condition (first load) and the first in the width direction (direction parallel to the central axis AX). Unlike the portion 93, in consideration of the occurrence of the second portion 94 having a second condition (second load) in which the load at the ground is greater than the load of the first portion 93 (first load), the heel and toe wear is reduced. Predict.

  That is, due to the camber angle θ, the tire 1 includes the tire 1 with the first portion 93 and the second portion 94 having a larger load in contact with the ground than the first portion 93. In the present embodiment, the measurement site 43 is defined at least in the second portion 94.

  In the present embodiment, the camber angle θ is set as a friction energy measurement condition using the friction energy tester 57. With the camber angle θ set on the tire 1, the friction energy at the measurement portion 43 defined in the second portion 94 is measured by the friction energy tester 57. Based on the measurement result, heel and toe wear at least in the second portion 94 is predicted.

  As described above, according to the present embodiment, by considering the camber angle θ, the heel and toe wear form of the second portion 94, which is a portion where the heel and toe wear is easily promoted by the camber angle θ, is accurately predicted. can do.

DESCRIPTION OF SYMBOLS 1 Tire 2 Carcass part 3 Belt layer 4 Belt cover 5 Bead part 6 Tread rubber 8 Side wall rubber 9 Side wall part 10 Tread part 11 Center part 12 Shoulder part 20 Groove 21 Main groove 22 Lug groove 22A Lug groove 22B Lug groove 22C Lug Groove 22D Lug Groove 22E Lug Groove 22F Lug Groove 22G Lug Groove 23 Sipe 31 Pitch 32 Block 32A Block 32B Block 32C Block 32D Block 41 Evaluation Section 43A Measurement Area 43B Measurement Area 44 First Attached Part 45 Rear Part 48 First Attached Area 49 Last Attached Area 50 processing device 50m storage unit 50p processing unit 51 calculation unit 52 analysis unit 53 input / output unit 54 terminal device 55 input device 56 output device 57 friction energy test machine 60 lane region 61 first lane region 62 second lane region 71 first region 71A part 7 B portion 72 second region 72A portion 72B portion 81 third region 81A portion 81B portion 82 fourth region 82A portion 82B portion 85 maximum width portion 86 range 86A end portion 86B end portion 87 maximum depth portion 88 range 88A end portion 88B end Part 89 Maximum slope part 90 Range 90A End part 90B End part 93 First part 94 Second part aveD Average value D1 Difference D2 Difference D3 Difference D4 Difference LW Predetermined width OD Tire outer diameter RD Tire rim diameter SW Tire total width W Tread contact width TDW tread width

Claims (14)

Preparing a test tire that is rotatable about a central axis and is provided with a plurality of groove patterns of the same or similar design in the circumferential direction of the central axis;
Defining an evaluation section of the test tire based on at least one of a pitch defined by one groove pattern and a block defined by two lug grooves arranged in the circumferential direction;
Measuring the friction energy of the first measurement site defined in the first arrival area including the first arrival portion of the evaluation section;
Measuring the frictional energy of the second measurement site defined in the rearward wearing region including the rearward wearing part of the evaluation section;
Predicting heel and toe wear of the test tire based on the difference between the friction energy of the first measurement site and the friction energy of the second measurement site;
Tire wear prediction method including A plurality of the evaluation sections are defined in the circumferential direction,
Measuring the friction energy of the first measurement site and the friction energy of the second measurement site for each of the plurality of evaluation sections;
The tire wear prediction method according to claim 1, further comprising: predicting the heel and toe wear based on the difference derived for each of a plurality of the evaluation sections.   The tire wear prediction method according to claim 2, wherein at least two types of dimensions of the evaluation section are determined with respect to the circumferential direction. The first measurement site is defined in the first arrival part,
The second measurement site is defined in the rear wearing part,
At least one measurement site is defined between the first measurement site and the second measurement site with respect to the circumferential direction,
Setting one of the first measurement site and the second measurement site as a reference site;
Calculating a first difference between the friction energy of the reference portion and the friction energy of the other of the first measurement portion and the second measurement portion;
Calculating a second difference between the friction energy of the reference portion and the friction energy of the at least one measurement portion;
The tire wear prediction method according to any one of claims 1 to 3, further comprising: predicting the heel and toe wear based on the first difference and the second difference. Setting at least two lane regions having a predetermined width in a direction parallel to the central axis,
The tire wear prediction method according to any one of claims 1 to 4, wherein the first measurement site and the second measurement site are defined in each of the plurality of lane regions. Between the first part at one end of the tread development width of the test tire and the second part on the equator plane side of the test tire from the first part, and the third part at the other end of the tread development width of the test tire. And determining the measurement part in one or both of the fourth part on the equatorial plane side of the test tire with respect to the third part,
The distance between the first part and the second part and the distance between the third part and the fourth part with respect to a direction parallel to the central axis are each 30% or less of the tread deployment width. The tire wear prediction method according to any one of claims 1 to 5. Defining the measurement site between a fifth site of the ground contact edge of the test tire and a sixth site on the equator plane side of the test tire from the fifth site;
Defining the measurement part between a seventh part closest to the ground contact end in the main groove of the test tire and an eighth part closer to the ground contact end than the seventh part,
The distance between the fifth part and the sixth part in a direction parallel to the central axis is 5 mm or less, and the distance between the seventh part and the eighth part is 10 mm or less. The tire wear prediction method according to claim 6. Extracting a maximum width portion having a maximum width in the lug groove or the sipe of the evaluation section,
The tire measurement method according to any one of claims 1 to 7, wherein the measurement site is determined within a range of 5 mm from the maximum width site in a direction parallel to the central axis. Extracting a maximum depth portion having a maximum depth in the lug groove or sipe of the evaluation section,
The tire measurement method according to any one of claims 1 to 7, wherein the measurement site is defined in a range within 5 mm from the maximum depth site in a direction parallel to the central axis. Extracting a maximum slope portion having a maximum slope angle with respect to a tire width direction in the lug groove or the sipe of the evaluation section,
The tire measurement method according to any one of claims 1 to 7, wherein the measurement site is defined within a range of 5 mm or less from the maximum slope site in a direction parallel to the central axis. Defining the evaluation section for a reference tire;
Measuring the friction energy of the first measurement site and the second measurement site of the reference tire under the same conditions as the measurement of the friction energy of the test tire;
Determining a reference value for the friction energy based on the difference between the friction energy of the first measurement site and the friction energy of the second measurement site of the reference tire;
Comparing the reference value with the frictional energy of the first measurement site and the second measurement site of the test tire;
Predicting heel and toe wear of the test tire based on the comparison results;
The tire wear prediction method according to any one of claims 1 to 10, comprising: Measuring the frictional energy of the measurement site defined in the evaluation section of the test tire in each of the standard use condition and the evaluation use condition;
Determining a reference value for the friction energy based on the difference between the friction energy of the first measurement site and the friction energy of the second measurement site of the test tire measured under the reference usage conditions;
Comparing the reference value and the frictional energy of the measurement site of the test tire measured under the evaluation use conditions;
Predicting heel and toe wear of the test tire under the evaluation use conditions based on the comparison result;
The tire wear prediction method according to any one of claims 1 to 10, comprising:   The difference between the friction energy of the first measurement site and the friction energy of the second measurement site of the test tire includes a ratio between the friction energy of the first measurement site and the friction energy of the second measurement site. The tire wear prediction method according to any one of claims 1 to 12. Setting a camber angle of the test tire,
The test tire includes a first portion, and a second portion having a load at grounding that is larger than the first portion, unlike the first portion in a direction parallel to the central axis,
The tire wear prediction method according to any one of claims 1 to 13, wherein the first measurement site and the second measurement site are defined in at least the second portion.