Testing method for airless tire and testing apparatus for airless tire

Abstract

To acquire data effective for analyzing damage to airless tires.SOLUTION: An airless tire 10 includes: an annular tread ring 11 that has a ground-contact surface 111; a hub 12 that is fixed to a member on the axle side; and a spoke part 13 that connects the tread ring 11 and the hub 12. A testing apparatus 20 for the airless tire 10 includes: a drum traveling device 21 that has a rotating drum 22; a support device 23 that has a support shaft 24 that supports the airless tire 10; an actuator 25 that displaces the support shaft 24 toward the drum 22 side to press the airless tire 10 against the drum 22 side; and a measuring instrument 26 that acquires the displacement amount of the airless tire 10 supported by the support shaft 24.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a test method for an airless tire and a test apparatus for an airless tire.

Background Art

[0002] As a wheel used for vehicles such as automobiles, pneumatic tires are widely adopted. In recent years, however, the development of airless tires has been underway. An airless tire has an annular tread ring having a ground contact surface, a hub fixed to a member on the axle side, and a spoke portion connecting the tread ring and the hub. The following Patent Document 1 discloses a test apparatus used for performance evaluation of an airless tire. A load is applied to one location on the upper part of the tread ring of the airless tire, and the amount of deflection is measured. Thereby, the rigidity of the tread ring is evaluated.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The test method disclosed in Patent Document 1 is a static test. That is, the airless tire is in a state fixed to the apparatus and not in a running state (rotating state). For this reason, it is impossible to obtain data effective for analyzing the damage of a running airless tire, and it is impossible to evaluate its durability, particularly the durability of the spoke portion.

[0005] An object of the present invention is to provide a test method capable of obtaining data effective for analyzing the damage of an airless tire and a test apparatus used for the test method.

Means for Solving the Problems

[0006] The test method for a non-pneumatic tire according to the present invention is a test method for a non-pneumatic tire having an annular tread ring having a ground contact surface, a hub fixed to a member on the axle side, and a spoke portion connecting the tread ring and the hub, the method comprising a drum running step of running the non-pneumatic tire by a drum running device, and an acquisition step of acquiring the amount of deflection of the non-pneumatic tire during drum running. In the acquisition step, the amount of displacement of the non-pneumatic tire is measured in a state where the non-pneumatic tire is displaced toward the drum side of the drum running device and pressed against the drum.

[0007] The test apparatus for a non-pneumatic tire according to the present invention is a test apparatus for a non-pneumatic tire having an annular tread ring having a ground contact surface, a hub fixed to a member on the axle side, and a spoke portion connecting the tread ring and the hub, the apparatus comprising a drum running device having a rotating drum, a support device having a support shaft for supporting the non-pneumatic tire, an actuator for displacing the support shaft toward the drum side to press the non-pneumatic tire against the drum side, a measuring instrument for acquiring the amount of displacement of the non-pneumatic tire supported by the support shaft, and a controller for controlling the actuator.

Advantages of the Invention

[0008] According to the present invention, it is possible to obtain data effective for analyzing damage to a non-pneumatic tire.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0010] 〔Details of Embodiments of the Present Invention〕 Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the drawings.

[0011] 〔Regarding the airless tire〕 The airless tire to be tested will be described. FIG. 1 is a side view showing an example of an airless tire. The airless tire 10 shown in FIG. 1 has an annular tread ring 11 having a ground contact surface 111, a hub 12 fixed to a member on the axle side, and a spoke portion 13 connecting the tread ring 11 and the hub 12.

[0012] The tread ring 11 is composed of a rubber member such as vulcanized rubber. A resin material may be added to the tread ring 11. The outer peripheral surface of the tread ring 11 becomes the ground contact surface 111 that contacts the ground (road surface). Although not shown, drainage grooves are provided in the ground contact surface 111. The spoke portion 13 is joined to the inner peripheral surface of the tread ring 11. It is preferable that a reinforcing cord layer is disposed inside the tread ring 11. The reinforcing cord layer is composed of a layer in which a plurality of organic fiber cords or steel cords are arranged in a predetermined direction. The reinforcing cord layer increases the rigidity of the tread ring 11 in one or both of the tire circumferential direction and the tire axial direction, and improves the handling stability.

[0013] The hub 12 is a portion fixed to a member on the axle side (flange of the hub unit), and is made of metal, for example. The hub 12 has a central disk portion 121 and a cylindrical portion 122 located on the outer peripheral side of the disk portion 121. The disk portion 121 and the cylindrical portion 122 are integral. In order to fix the airless tire 10 to the member on the axle side, a center bore 121a and attachment holes 121b for hub bolts are provided in the disk portion 121.

[0014] The spoke portion 13 is provided between the tread ring 11 and the hub 12 and connects them. The spoke portion 13 of the present embodiment has an outer ring portion 131 on the outer side in the tire radial direction, an inner ring portion 132 on the inner side in the tire radial direction, and a plurality of spoke elements 133. The outer ring portion 131 is an annular portion and is joined to the inner peripheral surface of the tread ring 11. The inner ring portion 132 is an annular portion and is joined to the outer peripheral surface of the hub 12 (cylindrical portion 122).

[0015] The spoke element 133 is a columnar portion extending in the tire radial direction and connects the outer ring portion 131 and the inner ring portion 132. The outer ring portion 131, the inner ring portion 132, and the spoke element 133 are integral. The spoke element 133 is not limited to the illustrated shape. The spoke element 133 relieves the impact input from the tread ring 11 by flexing during running.

[0016] The spoke portion 13 maintains the overall shape of the airless tire 10 and absorbs vibrations during running to improve the riding comfort performance. The spoke portion 13 is made of a thermosetting polymer material such as a thermosetting resin or a thermosetting elastomer. As a specific example, for example, a polyurethane-based, polyester-based, epoxy-based, phenol-based, silicone-based, or a mixture thereof, etc. are used. Considering heat resistance, strength, and flexibility, a polyurethane-based, or a thermosetting resin or thermosetting elastomer containing a polyurethane-based is preferable.

[0017] 〔Findings on which the present invention is based〕 In the case of a general pneumatic tire, the vertical spring constant of the tire is obtained by applying a specified load in the tire radial direction and measuring the amount of vertical deflection (deflection amount in the tire radial direction) at that time. In the case of a pneumatic tire, the internal pressure is maintained, and even in the case of running for a relatively long time, the vertical spring constant is difficult to change.

[0018] As shown in FIG. 1, the non-pneumatic tire 10 has the spoke portion 13 made of resin or elastomer. In the case of the non-pneumatic tire 10, in addition to the rigidity of the tread ring 11, the rigidity of the resin portion or the elastomer portion affects its vertical spring constant. That is, the rigidity of the spoke portion 13 affects the vertical spring constant of the non-pneumatic tire 10.

[0019] In the case of the non-pneumatic tire 10, during running, the temperature of the portion of the spoke portion 13 that is in contact with the tread ring 11 and the hub 12 in particular rises. When the temperature of the resin portion rises, it becomes soft, and the rigidity of the entire non-pneumatic tire 10 decreases. Due to the decrease in the rigidity, the vertical spring constant of the non-pneumatic tire 10 is likely to change. Therefore, the inventor focused on the characteristics of such a non-pneumatic tire 10, and by obtaining the amount of deflection of the non-pneumatic tire 10 that changes due to the rise in the temperature of the resin portion during running (during drum running), it was found that the durability of the non-pneumatic tire 10 can be evaluated, and the present invention has been completed.

[0020] Hereinafter, a test device for the non-pneumatic tire 10 and a test method performed using the test device will be described. FIG. 2 is a schematic configuration diagram of the test device.

[0021] 〔Test Device〕 The test device 20 includes a drum running device 21, a support device 23, an actuator 25, a measuring instrument 26, and a controller 27. Note that each part included in the test device 20 may have a configuration other than that shown in the figure, and the arrangement of each part can also be changed within the scope of the present invention.

[0022] The drum running device 21 includes a drum 22 and a drive unit 31 that rotates the drum 22. The outer peripheral surface 221 of the drum 22 serves as a running surface on which the non-pneumatic tire 10 is grounded. The portion including the outer peripheral surface of the drum 22 is sufficiently more rigid than the non-pneumatic tire 10 and does not elastically deform in the radial direction of the drum 22.

[0023] The drive unit 31 includes a housing 35 installed on the workbench or the ground, a rotating shaft 32 fixed to the drum 22, a transmission 33, and a motor 34. The transmission 33 and the motor 34 are housed in the housing 35. The rotating shaft 32 is rotatably supported by the housing 35. The rotating shaft 32 rotates by the drive of the motor 34. Due to the rotation of the rotating shaft 32, the drum 22 rotates around the central axis Cd of the drum 22. The transmission 33 changes the rotation speed of the motor 34. The rotation speed of the drum 22 is changed by the transmission 33. The rotation and stop of the drum 22, and the rotation speed of the drum 22 are controlled by a control signal output from the controller 27.

[0024] The support device 23 supports the airless tire 10. The support device 23 includes a support block 37 installed on the workbench or the ground, and a support shaft 24 that supports the airless tire 10. In the case of this embodiment, the support shaft 24 is rotatably supported by the support block 37. The support shaft 24 has a flange 241 at its tip, and the airless tire 10 (hub 12) is fixed to the flange 241. The airless tire 10, together with the support shaft 24, is rotatable around the central axis Ct of the airless tire 10.

[0025] Alternatively, the support shaft 24 may have a rolling bearing at its tip and be configured to rotatably support the airless tire 10. The support device 23 only needs to have a support shaft 24 that supports the airless tire 10 and be configured to rotate the airless tire 10 around the central axis Ct, and may be other than the illustrated configuration.

[0026] The actuator 25 is pneumatic, hydraulic, or electric, and displaces the support shaft 24. The directions in which the support shaft 24 is displaced by the actuator 25 are the direction in which the airless tire 10 approaches the drum 22 and the direction in which the airless tire 10 moves away from the drum 22. By approaching the airless tire 10 to the drum 22 side, the actuator 25 can bring the grounding surface 111 of the airless tire 10 into contact with the outer peripheral surface 221 of the drum 22.

[0027] The non-pneumatic tire 10 supported by the support shaft 24 is displaced in a direction closer to the drum 22 by the operation of the actuator 25, so that the non-pneumatic tire 10 is pressed against the drum 22. As the displacement amount of the non-pneumatic tire 10 in the direction of approaching the drum 22 increases, the force pressing the non-pneumatic tire 10 against the drum 22 increases.

[0028] By adjusting the displacement amount of the support shaft 24 by the actuator 25, that is, the displacement amount of the non-pneumatic tire 10, it becomes possible to press the non-pneumatic tire 10 against the drum 22 with an arbitrary pressing force. The operation of the actuator 25, that is, the displacement amount of the support shaft 24, is controlled by the control signal of the controller 27, and by this control, the pressing force is adjusted. The actuator 25 may have a configuration that displaces the support shaft 24 toward the drum 22 side and presses the non-pneumatic tire 10 against the drum 22 side, and may be other than the illustrated configuration.

[0029] FIG. 3 is an explanatory diagram of the displacement amount of the non-pneumatic tire 10 and the deflection amount of the non-pneumatic tire 10. The upper diagram of FIG. 3 shows the state immediately before pressing the non-pneumatic tire 10 against the drum 22, and the lower diagram of FIG. 3 shows the state where the non-pneumatic tire 10 is pressed against the drum 22. As shown in FIG. 3, the displacement amount S in the pressing direction of the non-pneumatic tire 10 corresponds to the deflection amount e of the non-pneumatic tire 10.

[0030] In the case of this embodiment, before rotating the drum 22, the non-pneumatic tire 10 is pressed against the drum 22 with an initial pressing force described later. In that state, the deflection amount (initial deflection amount described later) generated in the non-pneumatic tire 10 is used as a reference, and the deflection amount of the non-pneumatic tire 10 and its change are acquired.

[0031] The actuator 25 (see FIG. 2) has a load detector 28 that detects the output (thrust) of the actuator 25. The load detector 28 detects the pressing force of the airless tire 10 against the drum 22. It can also be said that the load detector 28 detects the reaction force that the airless tire 10 receives from the drum 22. The load detector 28 is, for example, a uniaxial load sensor. The detection signal, which is the detection result by the load detector 28, is transmitted to the controller 27.

[0032] The measuring device 26 is, for example, a linear scale. The measuring device 26 measures the displacement amount of the support shaft 24 that is displaced by the operation of the actuator 25. The displacement amount of the support shaft 24 becomes the displacement amount of the airless tire 10 supported by the support shaft 24. The measuring device 26 only needs to be configured to acquire the displacement amount of the airless tire 10 supported by the support shaft 24, and it may be configured other than measuring the displacement amount of the support shaft 24. For example, the measuring device 26 may be configured to measure the distance J (its change amount) from the central axis Ct of the airless tire 10 to the outer peripheral surface 221 of the drum 22. The data of the measurement result by the measuring device 26 is transmitted to the controller 27.

[0033] The controller 27 is composed of, for example, a computer device. The computer device has a CPU (arithmetic processing unit) and a storage device that stores a computer program and various data. By the CPU executing the computer program, the computer device (controller 27) has various processing functions.

[0034] As functions achieved by the CPU and the computer program, the computer device (controller 27) has an operation control function, a data acquisition function, and a measurement control function. The operation control function is a function that controls the operations of the actuator 25, the drum traveling device 21, and the support device 23 in order to make the airless tire 10 travel on the drum. The data acquisition function is a function that acquires and stores the displacement amount by the measuring device 26. The measurement control function is a function that controls the actuator 25 while comparing the parameter related to the displacement amount acquired by the measuring device 26 with the set value. Note that the "parameter related to the displacement amount" may be the "value" of the displacement amount or the "ratio" of the displacement amount or the like. Also, the "set value" is a value set in advance and stored in the controller 27.

[0035] As one of the operation control functions, the controller 27 controls the actuator 25 to maintain the pressing force of the airless tire 10 against the drum 22 within a predetermined range. As one of the measurement control functions, when the parameter related to the displacement amount acquired by the measuring device 26 reaches the set value, the controller 27 executes control to stop pressing the airless tire 10 against the drum 22 by the actuator 25. As one of the data acquisition functions, the controller 27 acquires and stores data on the deflection amount of the airless tire 10 from the displacement amount measured by the measuring device 26.

[0036] Specific examples of each of the above functions will be described together with the later test method. Note that one computer device (controller 27) may execute each of the above functions, or a plurality of computer devices (controller 27) may execute each of the above functions in cooperation.

[0037] As described above, according to the test device 20 of the present embodiment, in order to acquire the deflection amount of the airless tire 10 during drum running, the actuator 25 presses the airless tire 10 against the drum 22. During that time, the measuring device 26 measures the displacement amount of the airless tire 10. As described above, the displacement amount of the airless tire 10 in the state of being pressed against the drum 22 corresponds to the deflection amount of the airless tire 10. By measuring the displacement amount of the airless tire 10 during drum running, data on the deflection amount of the airless tire 10 can be obtained. The test by the test device 20 of the present embodiment is dynamic, and it is possible to acquire data effective for analyzing damage to the running airless tire 10.

[0038] [[Test Method]] A test method for the non-pneumatic tire 10 performed by the test apparatus 20 (see FIG. 2) having the above configuration will be described. The test method includes a preparation step of fixing the non-pneumatic tire 10 to the support shaft 24 of the support device 23, a drum running step of running the non-pneumatic tire 10 by the drum running device 21, and an acquisition step of acquiring data during the drum running step. The acquisition step is a step for acquiring the amount of deflection of the non-pneumatic tire 10 during drum running. The processes and operations performed in each step will be described below.

[0039] In the preparation step, the non-pneumatic tire 10 is fixed to the support shaft 24. The non-pneumatic tire 10 is in a state of being rotatable about the central axis Ct. The actuator 25 operates to bring the non-pneumatic tire 10 close to and press against the outer peripheral surface 221 of the drum 22. As a result, an initial deflection occurs in the non-pneumatic tire 10. The amount of deflection at this time is defined as the "initial deflection amount". The pressing force (load) of the non-pneumatic tire 10 against the drum 22 when the initial deflection amount is applied is defined as the "initial pressing force".

[0040] In the case of this embodiment, the initial pressing force is the load borne by the non-pneumatic tire 10 when a vehicle (automobile) equipped with the non-pneumatic tire 10 performs normal running. The initial deflection amount is the amount of deflection that occurs in the non-pneumatic tire 10 during normal running. The initial deflection amount is the amount of deflection in the static state where the non-pneumatic tire 10 is not rotating. In the drum running step, the drum 22 rotates. As a result, the non-pneumatic tire 10 rotates. The rotation speed of the drum 22 is maintained constant.

[0041] The non-pneumatic tire 10 rotates, and in a state where an initial deflection has occurred in the non-pneumatic tire 10, the non-pneumatic tire 10 is pressed against the drum 22 with a constant load (initial pressing force). In this state, as time passes, the temperature of the non-pneumatic tire 10, particularly the temperature of the tread ring 11 and a part of the spoke portion 13, rises. Among the spoke portions 13, the portion where the temperature rise is significant is the portion in contact with the tread ring 11 and the hub 12.

[0042] When the temperature of the non-pneumatic tire 10 rises, the hardness of the temperature-rise portion decreases, and the rigidity (vertical spring constant) of the non-pneumatic tire 10 decreases. The non-pneumatic tire 10 receives a load from the actuator 25 and is pressed against the drum 22. However, due to the decrease in rigidity, the pressing force decreases (the pressing force is lost). That is, the reaction force received by the actuator 25 from the drum 22 via the non-pneumatic tire 10 and the support shaft 24 decreases. This decrease in the pressing force (reaction force) is detected by the load detector 28.

[0043] In the acquisition step, the controller 27 controls the actuator 25 (operation control function) so that the force pressing the non-pneumatic tire 10 against the drum 22 is constant (initial pressing force). However, since it is difficult to make the pressing force exactly constant, it is sufficient that the pressing force is constant within a predetermined range. For the "predetermined range", the threshold values described below are set.

[0044] Figure 4 is a flowchart of the acquisition process. As described above, when the rigidity of the airless tire 10 decreases, the pressing force decreases. The load detector 28 detects the pressing force (step S11 in FIG. 4). When the controller 27 receives the data of the detection result of the pressing force, it compares the pressing force with a threshold value (step S12). When the pressing force has decreased below the threshold value (Yes in step S12), the controller 27 operates the actuator 25 to set the pressing force as the initial pressing force (step S13). In a specific example, the actuator 25 operates for a predetermined stroke and displaces the airless tire 10 in a direction approaching the drum 22. The amount of deflection of the airless tire 10 becomes larger than the initial amount of deflection.

[0045] In this way, even if the rigidity of the airless tire 10 decreases and the amount of deflection of the airless tire 10 becomes larger than the initial amount of deflection, a state can be obtained in which the airless tire 10 is continuously pressed against the drum 22 with the same force as the initial pressing force. During this period, the controller 27 continuously acquires and stores the amount of displacement of the airless tire 10 that the measuring device 26 acquires moment by moment (steps S14 and S24). As described above, in the acquisition process, while maintaining the state in which the airless tire 10 is pressed against the drum 22 with the pressing force within the predetermined range, the amount of displacement of the airless tire 10 is measured by the measuring device 26.

[0046] As time elapses in the running process, the temperature of the airless tire 10 gradually rises. Along with the temperature rise, the rigidity of the airless tire 10 decreases. Then, as described above, the force with which the airless tire 10 presses against the drum 22 decreases (the pressing force is lost). The pressing force is detected moment by moment by the load detector 28. When the pressing force has decreased beyond the threshold value (Yes in step S12), the controller 27 displaces the airless tire 10 in a direction closer to the drum 22 by the actuator 25 to set the pressing force as the initial pressing force (step S13).

[0047] In the acquisition process, such operations (steps S11 to S14, S24) are repeatedly executed (step S15) until the displacement amount measured by the measuring instrument 26 reaches the "set value". That is, the airless tire 10 is displaced toward the drum 22 side, and with the airless tire 10 pressed against the drum 22, the displacement amount of the airless tire 10 is measured. Then, the drum running is continued until the displacement amount measured by the measuring instrument 26 reaches the "set value".

[0048] When the displacement amount reaches the set value, the drum running is stopped. The set value is a parameter based on the amount of deflection in a predetermined state before the airless tire 10 reaches damage. Thereby, data on the amount of deflection of the airless tire 10 in a predetermined state before reaching damage is acquired. The set value is, as described above, a value set in advance and stored in the controller 27.

[0049] In the case of this embodiment, the set value is a parameter based on the amount of deflection at the stage of initial damage occurrence of the airless tire 10. For this reason, in the acquisition process, the drum running is continued until the displacement amount of the airless tire 10 obtained by measurement reaches the amount of deflection at the stage of initial damage occurrence of the airless tire 10. According to this operation, it becomes possible to acquire data on the amount of deflection of the airless tire 10 at the starting point of damage, which is before the airless tire 10 reaches damage. That data is effective for analysis regarding damage to the airless tire.

[0050] Note that the "amount of deflection at the stage of initial damage occurrence" that becomes the set value is a value obtained in advance by a plurality of tests or simulations on the same airless tire 10. An example of the set value will be described. The set value is a value of the increased amount of deflection for values ranging from 20% to 60% from the initial amount of deflection.

[0051] The lower limit value (20%) is not the value of the deflection amount due to the initial damage of the non-pneumatic tire 10, but is the value when, for example, the tread ring 11 softens due to heat generation during normal driving. The upper limit value (60%) is the value of the deflection amount at the time of initial damage (or at the time of damage occurrence) of the non-pneumatic tire 10. In the case of the non-pneumatic tire 10, since the deflection amount rapidly increases from the start of damage, if the deflection amount exceeds the upper limit value, there is a possibility that the non-pneumatic tire 10 has already been damaged.

[0052] In this way, by setting the lower limit value as the set value, the drum running is not stopped with respect to the deflection amount due to heat generation during normal driving. And by setting the upper limit value, the drum running is continued and the non-pneumatic tire 10 starts to be damaged, but the damage does not progress to breakage.

[0053] Note that the parameter regarding the displacement amount of the non-pneumatic tire 10 to be compared with the set value may be other than the "value" of the displacement amount. For example, the parameter regarding the displacement amount of the non-pneumatic tire 10 may be the "ratio" of the "distance (initial value) from the central axis Ct of the non-pneumatic tire 10 to the outer peripheral surface 221 of the drum 22 when the initial deflection amount occurs" and the "change amount (increase amount) of the displacement amount from the initial deflection amount". In this case, the set value to be compared is also a ratio.

[0054] As described above, in the acquisition step, as explained by the flowchart of FIG. 4, the controller 27 controls the actuator 25 while comparing the displacement amount (the parameter regarding the displacement amount) acquired by the measuring device 26 with the set value (measurement control function). The drum running is continued until the displacement amount reaches the set value (step S15 in FIG. 4). When the displacement amount reaches the set value (Yes in step S15), the drum running is stopped (step S16). "Stopping drum running" is an operation of gradually stopping the rotation of drum 22 and stopping the pressing of the airless tire 10 against the drum 22 by the actuator 25. The pressing of the airless tire 10 against the drum 22 is performed immediately (as quickly as mechanically possible).

[0055] In the acquisition step, the displacement amount is acquired moment by moment (at regular intervals) at a sampling frequency of 1 second or less. The controller 27 acquires data (data acquisition function) indicating the change over time of the displacement amount by the measuring device 26. The controller 27 acquires data indicating the change over time of the displacement amount until the displacement amount of the airless tire 10 reaches the set value.

[0056] FIG. 5 is a graph showing an example of data indicating the change over time of the displacement amount of the airless tire 10. By acquiring data indicating such a change over time, it becomes possible to read a minute change in the deflection amount of the airless tire 10. Thereby, it becomes possible to find the starting point of damage to the airless tire 10.

[0057] In FIG. 5, at time t1, the displacement amount reaches the set value and the drum running is stopped. The deflection amount at time t1 corresponds to the deflection amount e1 at the stage of initial damage occurrence of the airless tire 10. Note that when exceeding time t1, the damage to the airless tire 10 progresses rapidly, and at time t2, the airless tire 10 is completely damaged.

[0058] As described above, according to the test method of the present embodiment, with the airless tire 10 displaced toward the drum 22 and pressed against the drum 22, the displacement amount of the airless tire 10 is measured. The displacement amount in the pressing direction of the airless tire 10 corresponds to the deflection amount of the airless tire 10. The drum running is continued until the displacement amount (deflection amount) reaches the set value. In the case of the present embodiment, the set value is the deflection amount at the stage of initial damage occurrence of the airless tire 10. Therefore, it becomes possible to acquire data of the airless tire 10 at the starting point of damage.

[0059] Note that the set value may be set to the amount of deflection in a predetermined state before the airless tire 10 reaches damage. In the case of this embodiment, the predetermined state is the stage of initial damage occurrence. As a result, as shown in FIG. 5, data on the change over time of the amount of deflection of the airless tire 10 up to the stage of initial damage occurrence is obtained. As a result, it becomes possible to obtain data at the starting point of damage to the airless tire 10. That data is effective for analysis regarding damage to the airless tire and is utilized for improving the durability of the airless tire 10.

[0060] In the case of the airless tire 10, there are cases where the rate of change in the amount of deflection at the starting point of damage begins to change significantly beyond a threshold value. The controller 27 can obtain the rate of change by performing arithmetic processing on data indicating the change over time of the displacement amount, and can identify the starting point of damage and immediately before damage.

[0061] In the case of this embodiment, in the acquisition step, while maintaining the state in which the airless tire 10 is pressed against the drum 22 with a pressing force within a predetermined range, the displacement amount of the airless tire 10 is measured. Since the state in which the airless tire 10 is pressed against the drum 22 with a pressing force within a predetermined range is maintained, a steady running state is reproduced. For this reason, the acquired data is effective for analysis regarding damage to the airless tire 10 in the steady running state.

[0062] In the case of this embodiment, when the displacement amount reaches the set value, the controller 27 executes control to stop pressing the airless tire 10 against the drum 22 by the actuator 25. That is, when the displacement amount of the airless tire 10 reaches the set value, the pressing of the airless tire 10 against the drum 22 is released. By setting the set value as described above, this release operation prevents the damage to the airless tire 10 from progressing rapidly. That is, it becomes possible to prevent the loss of data at the starting point of damage to the airless tire 10.

Industrial Applicability

[0063] The test method for an airless tire and the test apparatus for an airless tire, as described above, are used for the development of various airless tires.

[0064] [Supplementary Note] The present invention includes the following aspects. (1) A test method for an airless tire having an annular tread ring with a ground contact surface, a hub fixed to a member on the axle side, and a spoke portion connecting the tread ring and the hub, the test method including a drum running step of running the airless tire by a drum running device, and an acquisition step of acquiring the deflection amount of the airless tire during drum running, wherein in the acquisition step, with the airless tire displaced to the drum side of the drum running device and pressed against the drum, the displacement amount of the airless tire is measured.

[0065] (2) The test method according to (1) above, wherein in the acquisition step, the drum running is continued until a parameter related to the displacement amount reaches a set value.

[0066] (3) The test method according to (2) above, wherein the set value is a parameter based on the deflection amount at the stage of initial damage occurrence of the airless tire.

[0067] (4) The test method according to any one of (1) to (3) above, wherein in the acquisition step, the displacement amount is measured while maintaining a state in which the airless tire is pressed against the drum with a pressing force within a predetermined range.

[0068] (5) The test method according to any one of (1) to (4) above, wherein in the acquisition step, data indicating the change over time of the displacement amount is acquired.

[0069] (6) The test device is a test device for a non-pneumatic tire having an annular tread ring with a ground contact surface, a hub fixed to a member on the axle side, and a spoke portion connecting the tread ring and the hub, and includes a drum running device having a rotating drum, a support device having a support shaft for rotatably supporting the non-pneumatic tire, an actuator for displacing the support shaft toward the drum side to press the non-pneumatic tire against the drum side, a measuring instrument for acquiring the displacement amount of the non-pneumatic tire supported by the support shaft, and a controller for controlling the actuator.

[0070] (7) The test device according to (6), wherein the controller controls the actuator to maintain the pressing force of the non-pneumatic tire against the drum within a predetermined range.

[0071] (8) The test device according to (6) or (7), wherein the controller controls the actuator while comparing a parameter related to the displacement amount acquired by the measuring instrument with a set value, and when the parameter related to the displacement amount reaches the set value, the controller executes control to stop the pressing of the non-pneumatic tire against the drum by the actuator.

Explanation of Signs

[0072] 10 ··· Non-pneumatic tire 11 ··· Tread ring 111 ··· Ground contact surface 12 ··· Hub 13 ··· Spoke portion 20 ··· Test device 21 ··· Drum running device 22 ··· Drum 221 ··· Outer peripheral surface 23 ··· Support device 24 ··· Support shaft 25 ··· Actuator 26 ··· Measuring instrument 27 ··· Controller

Claims

1. A test method for a non-pneumatic tire having an annular tread ring with a ground contact surface, a hub fixed to a member on the axle side, and a spoke portion connecting the tread ring and the hub, comprising: a drum running step of running the non-pneumatic tire by a drum running device; an acquisition step of acquiring the amount of deflection of the non-pneumatic tire during drum running; and having: in the acquisition step: measuring the displacement amount of the non-pneumatic tire while displacing the non-pneumatic tire to the drum side of the drum running device and pressing the non-pneumatic tire against the drum; A test method for a non-pneumatic tire.

2. The test method for a non-pneumatic tire according to claim 1, wherein in the acquisition step, the drum running is continued until a parameter related to the displacement amount reaches a set value.

3. The test method for a non-pneumatic tire according to claim 2, wherein the set value is a parameter based on the amount of deflection at the stage of initial damage occurrence of the non-pneumatic tire.

4. The test method for a non-pneumatic tire according to claim 1 or claim 2, wherein in the acquisition step, the displacement amount is measured while maintaining the non-pneumatic tire pressed against the drum with a pressing force within a predetermined range. The test method for a non-pneumatic tire according to claim 1 or claim 2.

5. The test method for a non-pneumatic tire according to claim 1 or claim 2, wherein in the acquisition step, data indicating a change over time of the displacement amount is acquired. The test method for a non-pneumatic tire according to claim 1 or claim 2.

6. A test device for a non-pneumatic tire having an annular tread ring with a ground contact surface, a hub fixed to a member on the axle side, and a spoke portion connecting the tread ring and the hub, comprising: a drum running device having a rotating drum; a support device having a support shaft for supporting the non-pneumatic tire; an actuator for displacing the support shaft to the drum side and pressing the non-pneumatic tire against the drum side; a measuring instrument for acquiring the displacement amount of the non-pneumatic tire supported by the support shaft; a controller for controlling the actuator; A test device for a non-pneumatic tire.

7. The test device for a non-pneumatic tire according to claim 6, wherein the controller controls the actuator to maintain the pressing force of the non-pneumatic tire against the drum within a predetermined range. The test device for a non-pneumatic tire according to claim 6.

8. The controller controls the actuator while comparing a parameter related to the displacement amount acquired by the measuring instrument with a set value. When the parameter regarding the displacement amount reaches the set value, the controller executes control to stop pressing the airless tire against the drum by the actuator. The airless tire testing apparatus according to claim 6 or claim 7.

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