Tire evaluation device and tire evaluation method

Abstract

To provide a tire evaluation device capable of quantitatively evaluating the aerodynamic characteristics of a tire.SOLUTION: A tire evaluation device 1 includes: a wind tunnel 10; a carriage 20 which can support a tire T inside the wind tunnel 10 in a state where a tire axis O1 extends in the horizontal direction, has a wheel 21a and can move in the X direction perpendicular to the tire axis O1 in the horizontal direction by rolling the wheel 21a; an air blowing device 3 which generates an airflow F inside the wind tunnel 10 by sending wind parallel to the X direction toward the tire T supported by the carriage 20 in the wind tunnel 10; and a load sensor 40 which measures the load in the X direction generated in the tire T by taking the displacement when the tire T moves together with the carriage 20 due to the airflow F as the input.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a tire evaluation device and a tire evaluation method. [Background technology]

[0002] Patent Documents 1 and 2 disclose a tire evaluation device and a tire evaluation method in which an airflow is sent to a tire held in a wind tunnel by an air blower, and the airflow around the tire is visualized by smoke. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-52979 A [Patent Document 2] JP 2019-52980 A Summary of the Invention [Problem to be solved by the invention]

[0004] The tire evaluation devices and tire evaluation methods of Patent Documents 1 and 2 visualize the airflow around the tire, and the visualized images tend to lead to subjective evaluations.

[0005] An object of the present invention is to provide a tire evaluation device and a tire evaluation method capable of quantitatively evaluating the aerodynamic characteristics of a tire. [Means for solving the problem]

[0006] One aspect of the present invention is Wind tunnel and a cart capable of supporting a tire in the wind tunnel with a tire axis extending in a horizontal direction, the cart having wheels and capable of moving in a first direction perpendicular to the tire axis in the horizontal direction by rolling the wheels; a blower that blows air in a direction parallel to the first direction toward a tire supported by the carriage in the wind tunnel to generate an airflow in the wind tunnel; a load sensor that measures a load in the first direction generated on the tire using, as an input, a displacement of the tire when the tire moves together with the cart due to the airflow; The present invention provides a tire evaluation device comprising:

[0007] According to one aspect of the present invention, the load acting on a tire based on the aerodynamic characteristics of the tire due to the airflow generated in a wind tunnel can be quantitatively measured by a load sensor. Moreover, since the input is the displacement of the dolly caused by rolling the wheels of the dolly, and there is no need to roll the tire, the device can be simplified.

[0008] Another aspect of the present invention is a carriage disposed in the wind tunnel and movable in a first direction when the wheels roll, the carriage supporting the tire with the tire axis extending horizontally; Wind is blown in parallel to the first direction toward a tire supported by the carriage in the wind tunnel to generate an airflow in the wind tunnel, measuring a load in the first direction acting on the tire using, as an input, a displacement of the tire when the tire moves together with the cart due to the airflow; evaluating the aerodynamic characteristics of the tire based on the measured load; A tire evaluation method is provided.

[0009] According to another aspect of the present invention, the load acting on a tire based on the aerodynamic characteristics of the tire due to the airflow generated in a wind tunnel can be quantitatively measured. Moreover, since the displacement of the dolly caused by rolling the wheels of the dolly is used as an input, the measurement can be easily performed since there is no need to roll the tire. [Brief description of the drawings]

[0010] [Figure 1] 1 is a side view showing a schematic configuration of a tire evaluation device according to an embodiment of the present invention. [Diagram 2]FIG. 2 is a plan view of the tire evaluation device as viewed from the direction of arrow A in FIG. [Diagram 3] FIG. 2 is a longitudinal sectional view of the tire evaluation device taken along line III-III in FIG. [Figure 4] FIG. 2 is a side view similar to FIG. 1, illustrating a state in which the dolly is in contact with the contact during measurement. [Diagram 5] FIG. 4 is a vertical cross-sectional view similar to FIG. 3, illustrating a state in which a camber angle is applied to a tire and measured. [Figure 6] FIG. 3 is a plan view similar to FIG. 2, illustrating a state in which a slip angle is applied to a tire and measured. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] A tire evaluation device and a tire evaluation method according to an embodiment of the present invention will be described below with reference to the accompanying drawings. Note that the following description is merely exemplary in nature and is not intended to limit the present invention, its application, or its uses.

[0012] Fig. 1 shows a side view of a tire evaluation device 1 according to one embodiment of the present invention. Fig. 2 shows a plan view of the tire evaluation device 1 as seen by an arrow A in Fig. 1. Fig. 3 shows a vertical cross-sectional view of the tire evaluation device 1 taken along line III-III in Fig. 1. As shown in Fig. 1, the tire evaluation device 1 includes a wind tunnel 10, a cart 20 supporting a tire T in the wind tunnel 10, an air blower 3 that blows air into the wind tunnel 10, a load sensor 40 that measures a load acting on the tire by an airflow F generated by the air blower 3, a rail 7 (guide member) that guides the movement of the cart 20, a smoke generator 30, and an imaging device 5.

[0013] The wind tunnel 10 has a bottom wall 11 that defines the lower end in the up-down direction, a top wall 12 that defines the upper end in the up-down direction, and a pair of side walls 13 that define both ends in the width direction. Inside the wind tunnel 10, an internal space 14 extending in the horizontal direction is defined by the bottom wall 11, the top wall 12, and the pair of side walls 13. In the following description, with regard to the directions of the tire evaluation device 1 and each component, the direction in which the wind tunnel 10 extends is referred to as the X direction, the width direction of the wind tunnel 10 is referred to as the Y direction, and the up-down direction of the wind tunnel 10 is referred to as the Z direction.

[0014] In this embodiment, the blower 3 is disposed at one end side in the X direction of the wind tunnel 10 (the right end in FIG. 1), and sends air into the internal space 14 to generate an airflow F toward the other end side in the X direction of the wind tunnel 10 (the left end in FIG. 1). That is, the blower 3 sends wind in the X direction (first direction) toward the tire T supported by the cart 20 in the wind tunnel 10, and generates an airflow F in the X direction in the wind tunnel 10. Note that the blower 3 may be disposed at the other end side in the X direction of the wind tunnel 10, and the air in the internal space 14 may be sucked in to generate an airflow F in the X direction in the wind tunnel 10.

[0015] The carriage 20 has a first base 21 having wheels 21a that roll on the rails 7, and a second base 22 that is supported by the first base 21 and has a tire T fixed thereto.

[0016] As shown in Fig. 2, the first base 21 has wheels 21a at each of the four corners. The wheels 21a are made of metal, such as aluminum or stainless steel. As shown in Fig. 3, the wheels 21a are provided with grooves 21b extending in the circumferential direction at approximately the center in the axial direction. The rails 7 are fitted into the grooves 21b. The second base 22 is supported immovably with respect to the first base 21 so as to move integrally with the first base 21 when an airflow F by the blower 3 is generated on the tire T. For example, a stopper (not shown) may be provided on the first base 21 to prevent the second base 22 from being displaced relative to the first base 21 toward the other end side in the X direction (the left side in FIG. 1).

[0017] The tire T is non-rotatably supported by the second mount 22 with the tire axis O1 facing the Y direction. In this embodiment, a band 23 is wound between the inner diameter portion T1 of the tire T and the second mount 22 in the Z direction, and the tire T is fixed to the second mount 22 by the band 23.

[0018] 2, a pair of rails 7 are provided in the Y direction, each extending parallel to the X direction. In other words, the rails 7 extend parallel to the flow direction of the airflow F from the blower 3. The rails 7 restrict the movement of the cart 20 in the Y direction when the cart 20 receives the airflow F from the blower 3, and the cart 20 moves only in the X direction. The rails 7 are made of a metal such as aluminum or stainless steel.

[0019] That is, both the wheels 21a and the rail 7 are made of a hard material, and the coefficient of friction between them is kept low, allowing the cart 20 to move with good sensitivity to the airflow F. In order to further reduce the coefficient of friction between the wheels 21a and the rail 7, both or either of the wheels 21a and the rail 7 may be plated or coated with lubricant.

[0020] The load sensor 40 has a contactor 41 to which a load in the X direction is input. The contactor 41 measures the load in the X direction when pressed by an object to be measured, and outputs the load as an electric signal. The load sensor 40 is disposed on the downstream side of the airflow F with respect to the dolly 20, such that the contactor 41 faces the dolly 20 (the first dolly 21 in this embodiment) in the X direction. In this embodiment, the contactor 41 is spaced a predetermined distance (e.g., 5 mm) from the dolly 20 at the start of measurement, and comes into contact with the dolly 20 after the dolly 20 has moved the predetermined distance.

[0021] Various sensors, such as a force gauge and a load cell, can be used as the load sensor 40. In this embodiment, the load sensor 40 is attached to a pair of posts 15 extending between the bottom wall 11 and the top wall 12 of the wind tunnel 10, but various configurations can be used to attach the load sensor 40 as long as sufficient support rigidity can be ensured against the load input from the tire T (cart 20).

[0022] The smoke generating device 30 has a single thin metal wire 31 stretched in the internal space 14 of the wind tunnel 10 and an electrical current supply device 32 for supplying electricity to the thin metal wire 31.

[0023] The thin metal wire 31 in this embodiment is stretched in the internal space 14 so as to extend linearly in the Z direction, with its upper end located on the top wall 12 side of the wind tunnel 10 and its lower end located on the bottom wall 11 side of the wind tunnel 10. The thin metal wire 31 is stretched upstream of the airflow F from the tire T supported by the cart 20. The thin metal wire 31 is provided with a loop 33. The Z direction position of the loop 33 is the same as the tire axis O1 of the tire T supported by the cart 20. Therefore, smoke generated from the loop 33 is caused to flow by the airflow F to a height position near the tire axis O1 with respect to the tire T.

[0024] A smoke-producing material 34 that generates heat when heated is held within the loop 33. The thin metal wire 31 has terminals 31a, 31b at both ends electrically connected to a current-carrying device 32 via conductors 35. The current-carrying device 32 in this embodiment applies a DC voltage to the thin metal wire 31. When a current is applied by the current-carrying device 32, the thin metal wire 31 generates resistance heat, and this resistance heat causes smoke to be generated from the smoke-producing material 34 held in the loop 33.

[0025] In this embodiment, the thin metal wire 31 is a nichrome wire. The thin metal wire 31 may be a solid wire or a twisted wire. The loop 33 is formed by winding the thin metal wire 31 and then twisting the thin metal wire 31 once at the base end of the wound portion.

[0026] The smoke generating material 34 in this embodiment is obtained by mixing liquid paraffin as a smoke generating liquid material with talc, which is an example of a powder material, as a viscosity imparting material, to impart viscosity such that the smoke generating liquid material does not fall off the loop 33. The smoke generating liquid material is not limited to liquid paraffin, and may be a material having similar properties. The powder material as a viscosity imparting material is not limited to talc, and for example, boron nitride (BN) powder may be used.

[0027] The imaging device 5 images at least the area around the tire T in the internal space 14 of the wind tunnel 10. In other words, the imaging device 5 images the airflow around the tire T visualized by smoke generated from the smoke-generating material 34. The flow lines of the airflow F visualized by the smoke are captured by the imaging device 5, and the airflow around the tire T can be evaluated by the captured video and / or still images. Note that by irradiating the smoke around the tire T with light (e.g., laser light), the airflow F around the tire T visualized by the smoke can be captured more clearly by the imaging device 5.

[0028] Next, a tire evaluation method using the tire evaluation device 1 will be described.

[0029] First, the tire T is fixed to the carriage 20 with the tire axis O1 extending in the Y direction. Specifically, the tire T is fixed to the second carriage 22 via a band 23. Here, the tire T is supported by the carriage 20 without being mounted on a wheel. The tire T is a ring having an inner diameter portion T1 (also called a bead) to which a wheel is mounted, and the inner diameter portion T1 is closed from both sides in the Y direction by a lid member 8 to form a closed space inside the tire. Note that it is preferable that the lid member 8 is not located on the outer side in the tire axial direction with respect to the tire T when viewed from the X direction so as not to affect the aerodynamic characteristics of the tire T.

[0030] The cover member 8 is preferably made of a material that is as light as possible in order to reduce the effect on the frictional force generated between the wheels 21a and the rails 7, and various materials such as plastic cardboard, cardboard paper, thick paper, etc. can be used.

[0031] Next, the second table 22 is supported on the first table 21 so as to move integrally with the first table 21. Next, the cart 20 is placed on the rail 7 so that the first table 21 faces the contact 41 of the load sensor 40 at a predetermined distance from the upstream side of the airflow F in the X direction. At this time, the rail 7 is fitted into the groove 21b of the wheel 21a.

[0032] Next, an airflow F is generated in the X direction by the blower device 3. The airflow F causes the tire T to receive a force toward the downstream side of the airflow F due to air resistance. As a result, as shown in FIG. 4, the cart 20 receives a force from the tire T and moves downstream in the X direction, and the first platform 21 comes into contact with the contact 41 of the load sensor 40. The load sensor 40 measures the load input to the contact 41 and outputs it as an electrical signal. Based on the electrical signal output from the load sensor 40, the load acting on the tire T due to the airflow F is estimated.

[0033] Although the contactor 41 may be brought into contact with the first table 21 at the start of measurement, it is preferable to separate it by a predetermined distance as in this embodiment. That is, if the contactor 41 is not in contact with the first table 21 at the start of measurement, it is possible to measure the load in a relatively stable state after movement without detecting a load that may include various resistances when the cart 20 starts to move from a stationary state.

[0034] In addition, the imaging device 5 captures the airflow F visualized by smoke around the tire T, and the flow lines of the airflow F around the tire T can be visualized and evaluated based on the captured video and / or still images.

[0035] The tire evaluation device 1 and the tire evaluation method according to the present embodiment provide the following advantages.

[0036] (1) The tire evaluation device 1 is Wind tunnel 10 and A cart 20 capable of supporting a tire T in a wind tunnel 10 with a tire axis O1 extending in a Y direction, the cart having wheels 21a and capable of moving in an X direction perpendicular to the tire axis O1 among horizontal directions by rolling the wheels 21a; A blower 3 that blows air in a direction parallel to the X direction to a tire T supported by a carriage 20 in the wind tunnel 10 to generate an airflow F in the wind tunnel 10; A load sensor 40 measures the load in the X direction generated on the tire T by using the displacement of the tire T when the tire T moves together with the cart 20 due to the air flow F as an input. It is equipped with: As a result, the load acting on the tire T due to the airflow F generated in the wind tunnel 10 based on the aerodynamic characteristics of the tire T can be quantitatively measured by the load sensor 40. Moreover, since the displacement of the carriage 20 caused by rolling the wheels 21a of the carriage 20 is used as an input, and there is no need to roll the tire T, the tire evaluation device 1 can be simplified.

[0037] (2) The vehicle further includes rails 7 for guiding the rolling of the wheels 21a in the X direction. As a result, the movement direction of the carriage 20 can be restricted only to the X direction along the airflow F. Therefore, even if a force is generated by the airflow F in the Y direction, which is a horizontal direction intersecting the X direction, on the tire T due to unevenness provided on the sidewall or buttress of the tire T, for example, the movement direction of the carriage 20 is restricted only to the X direction, so that the aerodynamic characteristics of the tire T can be stably evaluated based on the load acting in the X direction.

[0038] (3) The load sensor 40 has a contact 41 to which a load is input by contact, The contact 41 faces the carriage 20 in the first direction. As a result, the load can be measured on the cart 20 via the contacts 41, and the load can be measured with higher accuracy than when the load is measured on a tire which is made of rubber and therefore subject to elastic deformation.

[0039] (4) The load sensor 40 is located downstream of the airflow F with respect to the cart 20 in the X direction. As a result, the load sensor 40 is located downstream of the tire T in the airflow F, and is less likely to affect the airflow F supplied to the tire from the blower 3. Therefore, the airflow F can be stably supplied to the tire T, and the load can be stably measured.

[0040] (5) Tire evaluation method: A cart 20 is disposed in the wind tunnel 10 and is movable in the X direction when the wheels 21a roll. The cart 20 supports the tire T with the tire axis O1 extending in the Y direction. In the wind tunnel 10, wind is blown in parallel to the X direction toward the tire T supported by the cart 20, generating an airflow F in the wind tunnel 10. The displacement of the tire T when the tire T moves together with the cart 20 due to the airflow F is used as an input to measure the load in the X direction on the tire T. Evaluate the aerodynamic characteristics of tire T based on the measured loads This includes: As a result, the load acting on the tire T due to the airflow F generated in the wind tunnel 10 based on the aerodynamic characteristics of the tire T can be quantitatively and simply measured.

[0041] (6) The wheels 21a roll on the rails 7, so that the movement direction of the carriage 20 is restricted to only the X direction. As a result, the movement direction of the carriage 20 can be restricted to only the X direction, so that the aerodynamic characteristics of the tire T can be stably evaluated based on the load acting in the X direction.

[0042] (7) The load is measured using the cart 20 as the measurement object. As a result, the load can be measured more accurately on the cart 20 than on the tire T, which is made of rubber and therefore can be elastically deformed.

[0043] (8) The tire T is supported by the bogie 20 without being mounted on a wheel. As a result, the mass of the evaluation target can be reduced compared to when the tire T is mounted on a wheel, thereby reducing the frictional force acting on the carriage 20. This makes it easier to move the carriage 20 even in a low flow rate region where the airflow F is low, improving the evaluation accuracy of the aerodynamic characteristics of the tire T in the low flow rate region.

[0044] (9) The tire T is a torus having an inner diameter portion T1 at its radially inner end which is mounted on a wheel, The tire T has an opening on the radially inner side of the inner diameter portion T1 covered. As a result, the wind is not drawn into the inside of the tire T, and the load acting on the tire T by the airflow F is caused only by the outer surface of the tire T. Therefore, it is easy to evaluate the effect of the shape of the outer surface of the tire T on the aerodynamic characteristics.

[0045] The tire evaluation device and tire evaluation method according to the present invention are not limited to the configurations of the above-described embodiments, and various modifications are possible.

[0046] In the above embodiment, the tire T is configured to be supported on the bogie 20 with the tire axis O1 extending in the Y direction. However, for example, to simulate the state in which the tire is mounted on an actual vehicle, a camber angle may be applied so that the tire axis O1 is inclined in the Z direction, or a slip angle may be applied so that the tire axis O1 intersects with the Y direction.

[0047] For example, as shown in Fig. 5, the second table 22 is inclined in the Y direction with respect to the first table 21, for example, by using a spacer 18, so that a camber angle can be applied to the tire T. Also, as shown in Fig. 6, the second table 22 is rotated by a predetermined angle in the horizontal direction with respect to the first table 21 and placed on the tire T, so that a slip angle can be applied to the tire T. That is, the tire may be supported on the bogie 20 in a state in which a camber angle and / or a slip angle is applied. In this case, the aerodynamic characteristics of the tire T can be evaluated by simulating a state in which the tire T is mounted on an actual vehicle.

[0048] In the above embodiment, the aerodynamic characteristics of the tire T are evaluated based on the load measured by the load sensor 40. However, the aerodynamic characteristics of the tire T may be evaluated by excluding the frictional force acting on the wheels of the carriage 20, which is determined in advance, from the measured load. Specifically, in a state where the tire T is not supported by the carriage 20, that is, in a state where only the carriage 20 is present, for example, when the carriage 20 is moved manually in the X direction without operating the blower 3, the load at the time when the carriage 20 starts to move may be measured by the load sensor 40 as the maximum static frictional force, and the maximum static frictional force may be removed from the load measured in a state where the tire T is supported by the carriage 20 and the blower 3 is operated. In this case, the contribution of the carriage 20 is removed from the measured load, and the load acting due to only the tire T can be estimated. Therefore, the aerodynamic characteristics of the tire T can be evaluated more accurately based on the estimated value of the load due to only the tire T.

[0049] It is preferable to provide, for example, a wind guide plate (not shown) so that the airflow F generated from the blower 3 is blown only onto the tire T and does not hit the cart 20. This makes it possible to reduce the load measured by the load sensor 40 from including the load caused by the airflow F acting on the cart 20, and allows the aerodynamic characteristics of the tire T to be evaluated with higher accuracy.

[0050] In the above embodiment, the cart 20 is configured by the first unit 21 and the second unit 22, but may be configured as an integrated unit.

[0051] In addition, in the above embodiment, the rail 7 is fitted into the groove 21b of the wheel 21a, but instead, a groove may be provided in the rail and the wheel may be fitted into the groove of the rail, or various other guide means may be adopted.

[0052] The tire evaluation device and the tire evaluation method according to the present invention provide the following aspects.

[0053] [Aspect 1] Wind tunnel and a cart capable of supporting a tire in the wind tunnel with a tire axis extending in a horizontal direction, the cart having wheels and capable of moving in a first direction perpendicular to the tire axis in the horizontal direction by rolling the wheels; a blower that blows air in a direction parallel to the first direction toward a tire supported by the carriage in the wind tunnel to generate an airflow in the wind tunnel; a load sensor that measures a load in the first direction generated on the tire using, as an input, a displacement of the tire when the tire moves together with the cart due to the airflow; A tire evaluation device comprising:

[0054] [Aspect 2] Further, a rail is provided to guide the rolling of the wheel in the first direction. 2. A tire evaluation device according to claim 1.

[0055] [Aspect 3] The load sensor has a contactor to which a load is input by contact, The contactor faces the carriage in the first direction. 3. The tire evaluation device according to claim 1 or 2.

[0056] [Aspect 4] The load sensor is located downstream of the airflow with respect to the cart in the first direction. The tire evaluation device according to any one of the first to third aspects.

[0057] [Aspect 5] a carriage disposed in the wind tunnel and movable in a first direction when the wheels roll, the carriage supporting the tire with the tire axis extending horizontally; Wind is blown in parallel to the first direction toward a tire supported by the carriage in the wind tunnel to generate an airflow in the wind tunnel, measuring a load in the first direction acting on the tire using, as an input, a displacement of the tire when the tire moves together with the cart due to the airflow; evaluating the aerodynamic characteristics of the tire based on the measured load; Tire evaluation method.

[0058] [Aspect 6] The wheels are rolled on rails to restrict the movement direction of the carriage to only the first direction. 6. A tire evaluation method according to claim 5.

[0059] [Aspect 7] The load is measured by using the cart as a measurement object. The tire evaluation method according to aspect 5 or 6.

[0060] [Aspect 8] The tire is supported by the bogie without being mounted on a wheel. A tire evaluation method according to any one of aspects 5 to 7.

[0061] [Aspect 9] The tire is a torus having an inner diameter portion at a radially inner end thereof that is mounted on a wheel, The tire has an opening on the radially inner side of the inner diameter portion covered. 9. A tire evaluation method according to claim 8.

[0062] [Aspect 10] The tire is supported by the bogie with a slip angle and / or a camber angle. A tire evaluation method according to any one of aspects 5 to 9.

[0063] [Aspect 11] evaluating the tire aerodynamic characteristics based on a load obtained by subtracting a frictional force acting on the wheels of the bogie from the measured load; A tire evaluation method according to any one of aspects 5 to 10. [Explanation of symbols]

[0064] 1. Tire evaluation device 3. Blower 5. Imaging Equipment 7 Rail 8 Lid member 10 Wind tunnel 14 Interior Space 20 Carts 21 1st unit 21a wheels 21b Groove 22 2nd unit 30 Smoke Generator 40 Load Sensor 41 Contact F Airflow O1 Tire axis T Tire T1 Inner diameter

Claims

1. Wind tunnel and a cart capable of supporting a tire in the wind tunnel with a tire axis extending in a horizontal direction, the cart having wheels and capable of moving in a first direction perpendicular to the tire axis in the horizontal direction by rolling the wheels; a blower that blows air in a direction parallel to the first direction toward a tire supported by the carriage in the wind tunnel to generate an airflow in the wind tunnel; a load sensor that measures the load in the first direction generated on the tire using, as an input, a displacement of the tire when the tire moves together with the cart due to the airflow; A tire evaluation device comprising:

2. The vehicle further includes a guide member that guides the rolling of the wheel in the first direction. The tire evaluation device according to claim 1 .

3. The load sensor has a contactor to which a load is input by contact, The contactor faces the carriage in the first direction. The tire evaluation device according to claim 1 or 2.

4. The load sensor is located downstream of the airflow with respect to the cart in the first direction. The tire evaluation device according to claim 1 or 2.

5. a carriage disposed in the wind tunnel and movable in a first direction when the wheels roll, the carriage supporting the tire with the tire axis extending in a horizontal direction; A wind is blown in parallel to the first direction toward a tire supported by the carriage in the wind tunnel to generate an airflow in the wind tunnel, a load in the first direction acting on the tire is measured using as an input a displacement of the tire caused by the airflow together with the cart; evaluating the aerodynamic characteristics of the tire based on the measured load; Tire evaluation method.

6. The wheels are rolled on rails to restrict the movement direction of the carriage to only the first direction. The tire evaluation method according to claim 5 .

7. The load is measured by using the cart as a measurement object. The tire evaluation method according to claim 5 or 6.

8. The tire is supported by the bogie without being mounted on a wheel. The tire evaluation method according to claim 5 or 6.

9. The tire is a torus having an inner diameter portion at a radially inner end thereof that is mounted on a wheel, The tire has an opening on the radially inner side of the inner diameter portion covered. The tire evaluation method according to claim 8.

10. The tire is supported by the bogie with a slip angle and / or a camber angle. The tire evaluation method according to claim 5 or 6.

11. evaluating the tire aerodynamic characteristics based on a load obtained by subtracting a frictional force acting on the wheels of the bogie from the measured load; The tire evaluation method according to claim 5 or 6.

Images