Tire ground contact state measuring device

Abstract

To provide a tire grounding state measuring device capable of measuring a grounding state of a rolling tire.SOLUTION: The tire ground-contact state measurement device 10 includes a pseudo road surface plate 56 having a pseudo road surface 56a having irregularities corresponding to an actual road surface, a support shaft 56a that supports the tire 1 so as to be able to come into contact with the pseudo road surface 32a above the pseudo road surface plate 56, a shaft support portion 32 that horizontally supports the support shaft 32a in a rotatable state, a drive device 30 that horizontally moves the support shaft 32a while applying a downward load to the support shaft 32a and rolls the tire 1 on the pseudo road surface 56a while applying a ground-contact load to the tire 1, an emission device 81 that emits electromagnetic waves to a ground-contact surface of the tire 1 with the pseudo road surface 56a, and an imaging device 82 that is disposed below the pseudo road surface plate 56 and optically images the tire 1 rolling on the pseudo road surface 56a by detecting the electromagnetic waves transmitted through the pseudo road surface plate 56.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a tire contact state measuring device. [Background technology]

[0002] There is a demand for accurate measurement of the contact state of a tire on an uneven road surface that simulates an actual road surface. For example, Patent Document 1 discloses a method in which a tire is placed on a transparent plate having an uneven surface equivalent to an actual road surface with a fluorescent liquid interposed therebetween, and excitation light is irradiated onto the fluorescent liquid from below the transparent plate, and the fluorescence emitted from the fluorescent liquid is photographed with a photographing device disposed below the transparent plate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-084428 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 can measure the ground contact state of a stationary tire, but cannot measure a rolling tire, and therefore cannot measure the ground contact state when braking / driving forces are applied or when cornering.

[0005] In view of the above, an embodiment of the present invention has an object to provide a tire ground contact state measuring device capable of measuring the ground contact state of a rolling tire. [Means for solving the problem]

[0006] The present invention includes the embodiments shown below.

[0007] [1] A tire contact state measuring device comprising: a pseudo road surface plate having a pseudo road surface with unevenness equivalent to that of a real road surface; a support shaft above the pseudo road surface plate that supports a tire so that it can contact the pseudo road surface; a shaft support section that supports the support shaft horizontally in a rotatable state; a drive device that moves the support shaft horizontally while applying a downward load to the support shaft, thereby causing the tire to roll on the pseudo road surface while applying a contact load to the tire; an irradiation device that irradiates electromagnetic waves onto the contact surface of the tire with the pseudo road surface; and an imaging device that is arranged below the pseudo road surface plate and detects the electromagnetic waves that have passed through the pseudo road surface plate and optically photographs the tire rolling on the pseudo road surface.

[0008] [2] The tire contact state measuring device according to [1] above, further comprising a load detection unit that detects a load acting on the tire in the vertical direction.

[0009] [3] The tire contact state measuring device according to [1] or [2] above, wherein the drive device includes a camber angle adjusting unit that adjusts the camber angle of the tire relative to the pseudo road surface.

[0010] [4] The tire contact state measuring device according to any one of [1] to [3] above, wherein the drive device includes a slip angle adjustment unit that adjusts the slip angle of the tire relative to the simulated road surface.

[0011] [5] The tire contact state measuring device according to any one of [1] to [4] above, wherein the drive device includes a tire torque adjustment unit that adjusts the driving and braking force of the tire against the simulated road surface.

[0012] [6] The tire contact state measuring device according to any one of [1] to [5] above, further comprising an irradiation device arranged below the pseudo road surface plate and irradiating excitation light onto a fluorescent liquid interposed between the tire and the pseudo road surface via the pseudo road surface plate, the imaging device detecting fluorescence emitted from the fluorescent liquid and transmitted through the pseudo road surface plate. [7] The tire contact state measuring device according to any one of [1] to [6] above, further comprising an irradiation device arranged below the pseudo road surface plate and irradiating excitation light onto a fluorescent liquid interposed between the tire and the pseudo road surface via the pseudo road surface plate, the imaging device detecting fluorescence emitted from the fluorescent liquid and transmitted through the pseudo road surface plate. [Effects of the Invention]

[0013] According to this embodiment, it is possible to provide a tire ground contact state measuring device that can measure the ground contact state of a rolling tire. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a front view schematically illustrating a configuration of a tire contact state measuring device according to an embodiment. [Figure 2] FIG. 2 is a plan view schematically showing the tire contact state measuring device. [Figure 3] Cross section AA of Figure 2 [Figure 4] FIG. 2 is a block diagram showing the control configuration of the tire contact state measuring device of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, a tire contact state measuring device according to an embodiment will be described with reference to the drawings.

[0016] (1) Overall Configuration of Tire Ground Contact State Measuring Device 10 1 and 2 are diagrams showing a tire contact state measuring device 10 (hereinafter, sometimes simply referred to as "measurement device 10") according to one embodiment. The measurement device 10 includes a track section 20 extending in a predetermined direction (hereinafter, this direction will be referred to as the X direction), a drive device 30 that travels on the track section 20, a road surface section 50 on which a tire 1 to be measured rolls, an irradiation device 81 that irradiates the tire 1 with electromagnetic waves, a photographing device 82 that detects the electromagnetic waves that have passed through a pseudo road surface plate 56, and a control unit 100 (see FIG. 4) that controls the measurement device 10. The measurement device 10 measures the contact state of the tire 1 rolling on the pseudo road surface plate 56 by having the irradiation device 81 irradiate the tire 1 with electromagnetic waves and the photographing device 82 detect the electromagnetic waves that have passed through the pseudo road surface plate 56 while the tire 1 rolls on the pseudo road surface plate 56 provided on the road surface section 50.

[0017] Electromagnetic waves are a phenomenon in which periodic changes in electric and magnetic fields propagate through space as waves. Examples of electromagnetic waves include, but are not limited to, X-rays, ultraviolet rays, visible light, infrared rays, and radio waves (including terahertz waves).

[0018] As an embodiment, the following description will use as an example a measuring device 10 that measures the tire's contact state on a wet road surface. The measuring device 10 irradiates a fluorescent liquid interposed between the tire 1 and a simulated road surface 56a with excitation light and detects the fluorescence emitted from the fluorescent liquid to measure the tire's contact state. Each substance with fluorescent properties has its own specific absorption wavelength range and fluorescence wavelength range. The fluorescence used for imaging is generally in the visible light range, but electromagnetic waves invisible to the human eye, such as ultraviolet or infrared, can also be used. Ultraviolet or visible light is generally used as the excitation light, but the excitation light is selected to match the absorption wavelength range of the substance of interest.

[0019] (2) Track part 20 The track section 20 includes a plurality of linear guides 21 that guide the movement of the drive device 30 in the X direction, and a power section 22 that generates power. The power section 22 transmits the generated power to the drive device 30 via a belt mechanism (not shown) to drive the drive device 30 in the X direction.

[0020] (3) Drive unit 30 The drive unit 30 has a main frame 31 to which power is transmitted from the power section 22 of the track section 20, and is attached with a spindle section 32 that supports the wheel rim WR on which the tire 1 is mounted, and an alignment section 33 that adjusts the alignment and load of the tire 1 relative to the road surface section 50.

[0021] The spindle unit 32 is disposed above the road surface 50, and a wheel rim WR is attached to the spindle shaft 32a. Power generated by a spindle drive unit 32b (see FIG. 4), such as a motor, is transmitted to the spindle shaft 32a, which drives and rotates the tire 1 together with the wheel rim WR attached to the spindle shaft 32a. In other words, in this example, the spindle shaft 32a is a support shaft that supports the tire 1 above the road surface 50, and the spindle unit 32 is a shaft support unit that supports the support shaft, the spindle shaft 32a, horizontally in a rotatable state.

[0022] The spindle portion 32 is also provided with a six-component force sensor 32c that detects forces acting on the tire 1 in three orthogonal axial directions, namely the vertical direction, the rotational axis direction of the tire 1, and the X direction, as well as torque around each axis.

[0023] The alignment section 33 includes a load adjustment section 34, a slip angle adjustment section 35, and a camber angle adjustment section 36, and supports the spindle section 32 so that the position and angle of the spindle shaft 32a of the spindle section 32 can be changed.

[0024] The load adjustment unit 34 is a unit that moves the alignment unit 33 up and down to adjust the load applied to the tire 1 when the tire 1 attached to the wheel rim WR comes into contact with the road surface 50. The slip angle adjustment unit 35 rotates and moves the alignment unit 33 about a vertical line V to adjust the slip angle of the tire 1 attached to the wheel rim WR. The camber angle adjustment unit 36 ​​rotates and moves the spindle unit 32 about a rotation axis C that is parallel to the X direction to adjust the camber angle of the tire 1 attached to the wheel rim WR.

[0025] In such a driving device 30, the load adjustment unit 34 applies a downward load to the spindle shaft 32a while moving the spindle shaft 32a horizontally, and the tire 1 is rolled on a pseudo road surface 56a provided on the road surface unit 50 while applying a ground contact load to the tire 1.

[0026] (4) Road surface section 50 1 and 3, the road surface portion 50 comprises a frame 51 and a road surface main body 52 supported on the upper side of the frame 51. The road surface main body 52 is made of a metal plate, a resin plate, or the like arranged so that the upper surface is horizontal, and a fixing jig 54 and a pseudo road surface plate 56 are provided in mounting holes 53 that pass through the road surface main body 52 from top to bottom.

[0027] A spacer 55 is provided on the periphery of the mounting hole 53. The spacer 55 is provided below the upper surface of the road surface body 52, and the upper surface of the spacer 55 is a surface on which the periphery of the fixing jig 54 is placed. The spacer 55 has a mounting step 55a. A light absorbing portion 55b made of a black colored layer or the like is provided on the surface of the spacer 55 facing the space below the fixing jig 54. The light absorbing portion 55b absorbs excitation light emitted from an irradiation device 81 (described later) and fluorescence emitted from a fluorescent liquid interposed between the tire 1 and the simulated road surface 56a, thereby suppressing stray light generated in the space below the fixing jig 54.

[0028] The fixing jig 54 is made of a metal member formed in a predetermined shape so as to be flush with the upper surface of the road surface main body 52. ​​The fixing jig 54 has an observation window 57 that penetrates from top to bottom. The peripheral edge of the observation window 57 has a window step 58 that is recessed downward from the upper surface of the fixing jig 54. The peripheral edge of the pseudo road surface plate 56 is placed on the upper surface of the window step 58, and the pseudo road surface plate 56 covers the observation window 57 from above.

[0029] The fixing jig 54 preferably has processability that allows for accurate formation of the observation window 57 into which the pseudo road surface plate 56 is fitted, is strong enough to support the load of the tire 1, has strength and durability that prevents deformation of the observation window 57 even when the pseudo road surface plate 56 is repeatedly attached and detached, and is light enough that an operator can replace the fixing jig 54 when changing stages. In order to satisfy such processability, high strength, high durability, and light weight, the fixing jig 54 is preferably formed from aluminum or an aluminum alloy.

[0030] The pseudo road surface plate 56 is made of a plate-like body that is permeable to electromagnetic waves, and is preferably a transparent plate. The pseudo road surface plate 56 is larger than the contact patch 3 of the tire 1 and is large enough to fit the entire contact patch 3 within it. The pseudo road surface plate 56 has a pseudo road surface 56a with irregularities equivalent to those of an actual road surface on at least one of its front and back surfaces, and in this example, the surface opposite the pseudo road surface 56a is flat. The pseudo road surface plate 56 is placed on the window step 58 of the fixing jig 54 with the pseudo road surface 56a facing upward. The thickness of the pseudo road surface plate 56 is adjusted so that the pseudo road surface 56a is flush with the road surface main body 52 and the upper surface of the fixing jig 54 when placed on the window step 58.

[0031] There are no particular limitations on the method for producing the transparent pseudo-road panel 56 with the pseudo-road surface 56a, and it can be produced, for example, by molding asphalt corresponding to the actual road surface using silicone rubber, pouring transparent resin into the mold, and curing it in a vacuum degassed state. Examples of transparent resins include urethane-based resins.

[0032] The simulated road surface plate 56 is replaceably installed on the window step 58 of the fixing jig 54. Multiple plates with various uneven shapes are prepared depending on the road surface to be tested, and one can be selected and installed. Note that the simulated road surface plate 56 may be adhesively fixed to the fixing jig 54 as necessary, for example, when a sealant is provided between the simulated road surface plate 56 and the observation window 57 of the fixing jig 54 to provide a liquid-tight seal. When fixing the simulated road surface plate 56 to the fixing jig 54, by preparing multiple fixing jigs 54 to which simulated road surface plates 56 with different uneven shapes are fixed, it is possible to measure the contact state for simulated road surfaces with a variety of uneven shapes.

[0033] (5) Irradiation device 81 and imaging device 82 Below the road surface portion 50, there is provided an irradiation device 81 for irradiating electromagnetic waves onto the contact portion 3 between the tire 1 and the pseudo road surface 56a through the pseudo road surface plate 56, and an imaging device 82 for detecting the electromagnetic waves that have passed through the pseudo road surface plate 56 and performing optical imaging.

[0034] As shown in FIG. 3, the irradiation device 81 includes a light source 83, a rod lens 84, and a dichroic mirror 85.

[0035] The light source 83 generates excitation light that is irradiated onto the fluorescent liquid 2 interposed between the tire 1 and the simulated road surface 56a.

[0036] The rod lens 84 converts the excitation light generated by the light source 83 into a planar light beam that spreads uniformly in a predetermined shape, such as a rectangle, and emits the light. The irradiation area of ​​the light beam emitted from the rod lens 84 is preferably larger than the area of ​​the contact portion 3 between the tire 1 and the simulated road surface 56a.

[0037] The dichroic mirror 85 reflects light in a specific wavelength band that includes the wavelength of the planar excitation light emitted from the rod lens 84, and transmits electromagnetic waves that pass through the pseudo road surface plate 56 and travel downward. The dichroic mirror 85 can be selected and used appropriately according to the excitation spectrum and fluorescence spectrum of the fluorescent dye used in the fluorescent liquid 2.

[0038] The wavelength of the excitation light emitted by the light source 83 is appropriately selected to match the excitation spectrum of the fluorescent dye contained in the fluorescent liquid 2, and a light source having a peak wavelength near the peak wavelength of the excitation spectrum is preferably used.

[0039] Any device may be used as the light source 83 as long as it is capable of generating electromagnetic waves in a wavelength band capable of exciting the fluorescent liquid 2. For example, when irradiating ultraviolet light as excitation light, a mercury lamp or an ultraviolet LED can be used as the light source 83, but an ultraviolet LED is preferably used as the light source 83 because the excitation light generated is highly monochromatic.

[0040] The image capturing device 82 detects electromagnetic waves that pass through the pseudo road surface plate 56 and travel downward from the contact portion 3 between the tire 1 and the pseudo road surface 56a.

[0041] In this example, the photographing device 82 detects the fluorescence emitted from the fluorescent liquid 2 present in the ground contact portion 3 and transmitted through the pseudo road surface plate 56. The photographing device 82 is equipped with a camera that photographs the fluorescence transmitted through the pseudo road surface plate 56 (see FIG. 3). The camera that constitutes the photographing device 82 may be, for example, a single-lens reflex camera, a high-speed camera, a CCD camera, a video camera, or the like.

[0042] In addition, the photographing device 82 may be a device that detects reflected waves formed when electromagnetic waves irradiated from the irradiation device 81 are reflected by the grounded portion 3, or a device that detects electromagnetic waves emitted from the grounded portion 3 due to the electromagnetic waves irradiated from the irradiation device 81.

[0043] In this example, a filter that transmits only light of a specific wavelength band and separates it from light of other wavelength bands may be provided between the light source 83 and the dichroic mirror 85, or between the dichroic mirror 85 and the imaging device 82.

[0044] The irradiation device 81 may be configured to be movable in the horizontal direction so that the position at which the planar excitation light is irradiated onto the contact portion 3 between the tire 1 and the simulated road surface 56a can be changed. The photographing device 82 may be configured to be movable in the horizontal direction in accordance with the movement of the irradiation device 81.

[0045] (6) Control unit 100 As shown in FIG. 4, the control unit 100 has a main control unit 100a and a memory unit 100b, and is connected to the power unit 22, the spindle drive unit 32b, the six-component force sensor 32c, the load adjustment unit 34, the slip angle adjustment unit 35, the camber angle adjustment unit 36, the light source 83 of the irradiation device 81, and the photographing device 82 via a communication interface.

[0046] The main control unit 100a is composed of a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory) for expanding programs, etc. The main control unit 100a executes a program stored in the storage unit 100b to control each unit connected to the control unit 100 and measure the contact state of the tire 1 rolling on the simulated road surface 56a of the simulated road surface plate 56.

[0047] Furthermore, the main control unit 100a executes a program stored in the storage unit 100b to realize an image processing unit 100c that processes image data acquired by the photographing device .

[0048] (7) Method for measuring the contact state of the tire 1 using the measuring device 10 Next, a method for measuring the contact state of the tire 1 rolling on the pseudo road surface plate 56 using the measuring device 10 will be described.

[0049] Before measuring the ground contact state of the tire 1, first, a pseudo road surface plate 56 is fixed to the window step 58 of the road surface portion 50 with the pseudo road surface 56a facing upward. Then, fluorescent liquid 2 is poured onto the uneven pseudo road surface 56a, filling the pseudo road surface 56a with fluorescent liquid 2. As the fluorescent liquid 2, for example, an aqueous solution containing a hydrophilic fluorescent dye (e.g., pyranine) whose excitation spectrum and fluorescence spectrum have a peak wavelength difference of 100 nm or more is used.

[0050] Next, the wheel rim WR with the tire 1 mounted thereon is attached to the spindle shaft 32a of the spindle portion 32, and the drive unit 30 is placed in an initial position set at a predetermined position in the X direction.

[0051] The tire 1 is inflated to an internal pressure. The internal pressure may be the air pressure determined for each tire by a standard system including the standard on which the tire is based, such as the maximum air pressure in the case of truck / bus tires and light truck tires in the case of JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the case of TRA, or "INFLATION PRESSURE" in the case of ETRTO, and typically 180 kPa, 220 kPa, etc. in the case of passenger car tires, or the air pressure set on an actual vehicle.

[0052] Next, with the tire 1 moving upward away from the road surface body 52 of the road surface portion 50, the slip angle adjustment unit 35 adjusts the slip angle to a preset value, and the camber angle adjustment unit 36 ​​adjusts the camber angle to a preset value.

[0053] Thereafter, the load adjusting unit 34 lowers the wheel rim WR to bring the tire 1 mounted on the wheel rim WR into contact with the upper surface of the road surface body 52, and applies a predetermined load to the tire 1.

[0054] When the load adjustment unit 34 applies a downward load to the tire 1, the six-component force sensor 32c functions as a load detection unit and detects the downward load acting on the tire 1. When the six-component force sensor 32c detects the load acting on the tire 1, the control unit 100 applies a predetermined load to the tire 1 by controlling the load adjustment unit 34 based on the detection result of the six-component force sensor 32c.

[0055] The load applied to the tire 1 may be a normal load, a load equivalent to that of an actual vehicle, or a value 0.2 to 1.5 times these loads, or any other value depending on the purpose of the ground contact characteristic evaluation. Alternatively, the load may be set at multiple levels, and the ground contact state may be measured at each load to evaluate the relationship between the load and the ground contact characteristic. The normal load here refers to the load determined for each tire by each standard in the standard system, including the standard on which the tire is based. For example, the normal load may be the maximum load capacity in the JATMA standard, the maximum value listed in the table above in the TRA standard, or the "LOAD CAPACITY" in the ETRTO standard. If the tire is for a passenger car, it may also be a load equivalent to 88% of these loads.

[0056] Next, the power unit 22 is driven, and the drive device 30 travels in the X direction at a preset speed. By setting the spindle drive unit 32b to an idling state in advance, the tire 1 rotates along with the drive device 30 at a peripheral speed substantially the same as the travel speed, and rolls freely on the pseudo road surface 56a of the pseudo road surface plate 56. At this time, by controlling the spindle drive unit 32b to apply a preset torque, the tire 1 rolls on the pseudo road surface 56a of the pseudo road surface plate 56 in a driving state or a braking state. In other words, in this embodiment, the spindle drive unit 32b functions as a tire torque adjustment unit that adjusts the driving force or braking force of the tire 1.

[0057] At least while the tire 1 is rolling on the pseudo road surface 56a, the irradiation device 81 emits excitation light from the light source 83, and the imaging device 82 detects the fluorescence emitted from the fluorescent liquid 2 present in the contact area 3 and transmitted through the pseudo road surface plate 56 at predetermined time intervals.

[0058] That is, the excitation light emitted from the light source 83 is reflected by the dichroic mirror 85 and irradiated from the underside of the pseudo road surface plate 56 onto the fluorescent liquid 2 interposed between the tire 1 and the pseudo road surface 56a. This causes the fluorescent pigment contained in the fluorescent liquid 2 to transition from the ground state to an excited state. The excited fluorescent pigment then returns to the ground state, emitting fluorescence. The emitted fluorescence is transmitted through the pseudo road surface plate 56 and the dichroic mirror 85 in that order, and is then optically photographed by the imaging device 82. The imaging device 82 captures multiple images by continuously photographing the fluorescence that has transmitted through the pseudo road surface plate 56 and the dichroic mirror 85 at predetermined time intervals, and stores the captured images in the memory unit 100b.

[0059] The image processing unit 100c converts the image stored in the storage unit 100b into a luminance image (fluorescence intensity image) that represents the luminance distribution of the fluorescence using a known method, and binarizes the luminance image to generate a binary image.

[0060] The image processing unit 100c then evaluates the contact characteristics based on the generated binary image. For example, the number of black pixels in the binary image is counted, and the contact area occupancy rate ([number of black pixels] / [total number of pixels in the image]), which is the ratio of the number of black pixels to the total number of pixels in the binary image, is calculated. By calculating the contact area occupancy rate, the true contact area of ​​the tire 1 rolling on the simulated road surface 56a, which has irregularities that simulate an actual road surface, can be measured.

[0061] (8) Effects The measuring device 10 according to the embodiment described above can capture electromagnetic waves that have passed through the pseudo road surface plate 56 from below the pseudo road surface plate 56 on which the tire 1 is rolling, making it possible to measure the contact state of the tire rolling on the pseudo road surface 56a.

[0062] In this embodiment, a six-component force sensor 32c is provided to detect a downward load acting on the tire 1 that is in contact with the pseudo road surface 56a, and therefore, while the six-component force sensor 32c is measuring the load, the load adjustment unit 34 can apply a load to the tire 1. Therefore, a specified load can be applied to the tire 1 with high precision, and the tire contact state can be measured with high precision.

[0063] The measuring device 10 of this embodiment is provided with a slip angle adjustment unit 35 that adjusts the slip angle of the tire 1 relative to the pseudo road surface 56a and a spindle drive unit 32b that drives the spindle shaft 32a to rotate, so that the tire contact state can be measured when the tire 1 is rolling, braking, and cornering.

[0064] The measuring device 10 of this embodiment is provided with a camber angle adjustment unit 36, so that the contact state of the tire rolling on the pseudo road surface 56a can be measured while controlling the camber angle of the tire 1 relative to the pseudo road surface 56a.

[0065] In the measuring device 10 of this embodiment, by employing an ultraviolet LED as the light source 83, it is possible to generate highly monochromatic excitation light, so there is no need to provide a filter that transmits only light in a predetermined wavelength band between the light source 83 and the dichroic mirror 85, and the excitation light is not attenuated by the filter. Therefore, it is possible to reduce the output of the light source 83, make it more compact, and reduce the cost.

[0066] Although the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as defined in the claims. [Explanation of symbols]

[0067] 1... tire, 2... fluorescent liquid, 3... ground contact portion, 10... measuring device, 20... track portion, 21... linear guide, 22... power portion, 30... carriage, 31... main frame, 32... spindle portion, 32a... spindle shaft, 32b... spindle drive portion, 32c... six-component force sensor, 33... alignment portion, 34... load adjustment portion, 35... slip angle adjustment portion, 36... camber angle adjustment portion, 50... road surface portion, 51... frame, 52... road surface body, 53... mounting hole, 54... fixing jig, 55... spacer, 55a... mounting step portion, 55b... light absorbing portion, 56... simulated road surface plate, 56a... simulated road surface, 57... observation window, 58... window step portion, 81... irradiation device, 82... photographing device, 83... light source, 84... rod lens, 85... dichroic mirror

Claims

1. a pseudo road surface plate having a pseudo road surface with unevenness equivalent to that of a real road surface; a support shaft that supports a tire above the pseudo road plate so that the tire can come into contact with the pseudo road surface; a shaft support portion that horizontally supports the support shaft in a rotatable state; a drive device that moves the support shaft in a horizontal direction while applying a downward load to the support shaft, thereby rolling the tire on the simulated road surface while applying a ground contact load to the tire; an irradiation device that irradiates electromagnetic waves onto a contact surface of the tire with the simulated road surface; an imaging device disposed below the pseudo road surface plate, which detects electromagnetic waves transmitted through the pseudo road surface plate and optically images the tire rolling on the pseudo road surface; A tire contact state measuring device comprising:

2. The tire contact state measuring device according to claim 1 , further comprising a load detection unit that detects a load acting on the tire in a vertical direction.

3. The tire contact state measuring device according to claim 1 , wherein the drive device includes a camber angle adjusting unit that adjusts a camber angle of the tire relative to the simulated road surface.

4. 2. The tire contact state measuring device according to claim 1, wherein the drive device includes a slip angle adjusting unit that adjusts a slip angle of the tire relative to the simulated road surface.

5. 2. The tire contact state measuring device according to claim 1, wherein the driving device includes a tire torque adjusting unit that adjusts the driving and braking forces of the tire relative to the simulated road surface.

6. 2. The tire contact state measuring device according to claim 1, further comprising an irradiation device disposed below the pseudo road surface plate and irradiating excitation light onto fluorescent liquid interposed between the tire and the pseudo road surface via the pseudo road surface plate, wherein the imaging device detects fluorescence emitted from the fluorescent liquid and transmitted through the pseudo road surface plate.

7. 2. The tire contact state measuring device according to claim 1, wherein the irradiation device includes an ultraviolet LED that irradiates ultraviolet light onto a fluorescent liquid interposed between the tire and the pseudo road surface, and the imaging device detects the fluorescence emitted from the fluorescent liquid and transmitted through the pseudo road surface plate.

Images