CN109655287B - Tire grounding state evaluation method - Google Patents
Tire grounding state evaluation method Download PDFInfo
- Publication number
- CN109655287B CN109655287B CN201811035726.3A CN201811035726A CN109655287B CN 109655287 B CN109655287 B CN 109655287B CN 201811035726 A CN201811035726 A CN 201811035726A CN 109655287 B CN109655287 B CN 109655287B
- Authority
- CN
- China
- Prior art keywords
- test piece
- rubber test
- film thickness
- tire
- contact state
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000011156 evaluation Methods 0.000 title claims abstract description 28
- 238000012360 testing method Methods 0.000 claims abstract description 71
- 229920001971 elastomer Polymers 0.000 claims abstract description 62
- 239000007788 liquid Substances 0.000 claims abstract description 44
- 238000009826 distribution Methods 0.000 claims abstract description 29
- 238000005259 measurement Methods 0.000 claims abstract description 28
- 230000005284 excitation Effects 0.000 claims abstract description 10
- 238000003825 pressing Methods 0.000 claims abstract description 8
- 230000001678 irradiating effect Effects 0.000 claims abstract description 4
- 238000000695 excitation spectrum Methods 0.000 claims description 18
- 239000007850 fluorescent dye Substances 0.000 claims description 18
- 238000002189 fluorescence spectrum Methods 0.000 claims description 15
- ZEQNRFCMIQBXTM-UHFFFAOYSA-K trisodium;4-hydroxypyrene-1,2,3-trisulfonate Chemical group [Na+].[Na+].[Na+].[O-]S(=O)(=O)C1=C(S([O-])(=O)=O)C(S([O-])(=O)=O)=C2C(O)=CC3=CC=CC4=CC=C1C2=C34 ZEQNRFCMIQBXTM-UHFFFAOYSA-K 0.000 claims description 15
- 239000000049 pigment Substances 0.000 claims 1
- 238000000034 method Methods 0.000 description 18
- 238000010586 diagram Methods 0.000 description 4
- 238000003384 imaging method Methods 0.000 description 4
- 230000003287 optical effect Effects 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 230000002378 acidificating effect Effects 0.000 description 2
- 238000011088 calibration curve Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 230000003746 surface roughness Effects 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 239000010426 asphalt Substances 0.000 description 1
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000004040 coloring Methods 0.000 description 1
- 238000003271 compound fluorescence assay Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000013013 elastic material Substances 0.000 description 1
- 230000005281 excited state Effects 0.000 description 1
- 238000001917 fluorescence detection Methods 0.000 description 1
- 238000002795 fluorescence method Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 230000001443 photoexcitation Effects 0.000 description 1
- 229920005749 polyurethane resin Polymers 0.000 description 1
- 238000001028 reflection method Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229920002379 silicone rubber Polymers 0.000 description 1
- 239000004945 silicone rubber Substances 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 238000007794 visualization technique Methods 0.000 description 1
- 239000004636 vulcanized rubber Substances 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M17/00—Testing of vehicles
- G01M17/007—Wheeled or endless-tracked vehicles
- G01M17/02—Tyres
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M17/00—Testing of vehicles
- G01M17/007—Wheeled or endless-tracked vehicles
- G01M17/02—Tyres
- G01M17/027—Tyres using light, e.g. infrared, ultraviolet or holographic techniques
Abstract
The invention provides a tire ground contact state evaluation method for evaluating a tire ground contact state with high accuracy based on a correlation between a tire contact area and a friction coefficient when running on a wet road surface. Comprises the following steps: pressing a rubber test piece against a ground surface which is provided on one surface of a transparent plate and has irregularities corresponding to an actual road surface through a fluorescent liquid, measuring a load when the rubber test piece slides while moving straight, and measuring a friction coefficient between the ground surface and the rubber test piece; irradiating excitation light to the fluorescent liquid interposed between the ground surface and the rubber test piece from the opposite side of the transparent plate to the ground surface, and measuring the luminance distribution of fluorescence emitted from the fluorescent liquid; obtaining a 2-valued image by using the obtained brightness distribution as a reference and arbitrary brightness as a threshold value to obtain a contact area; the increase or decrease of the contact area is determined from the difference between 2 or more 2-valued images having different measurement parameters.
Description
Technical Field
The present invention relates to a method for evaluating a tire contact state based on a correlation between a tire contact area and a friction coefficient when running on a wet road surface.
Background
Conventionally, as a method for evaluating a ground contact state of a tire, there has been adopted: a method of visually observing the ground shape of a tire while grounding the tire on a flat plate, specifically, a visualization method such as an optical interference method or a total reflection method is known.
However, since the tire characteristics when the tire is pressed against the flat plate are different from those on the actual road surface, a method capable of evaluating the uneven surface corresponding to the actual road surface (hereinafter referred to as the actual road surface) has been demanded. To achieve this object, for example, patent document 1 proposes the following method: a method of imaging a ground contact shape of a tire by grounding the tire to a ground contact surface having a surface provided with irregularities corresponding to an actual road surface, has also been proposed: in order to improve the consistency with the actual vehicle evaluation, the space portion on the ground contact surface was filled with a coloring liquid and then the tire was grounded, and photographing was performed.
Although the method described in patent document 1 can evaluate the ground contact state on a wet road surface, it is difficult to achieve measurement accuracy that should be ensured in principle in the method using a colored liquid, and there is a problem in terms of scalability.
In particular, when the surface roughness of the surface of the road aggregate is measured by a contact-type roughness meter (ltd) MITUTOYO, the arithmetic average roughness (Ra) of the surface of the road aggregate is about 20 μm. It is conceivable that: in the dynamic sliding state, the thin water film formed on the surface of the aggregate having the surface roughness is influenced, and thus a method having excellent measurement accuracy is required which can detect a thin portion of the film thickness.
Therefore, as a method for evaluating a ground contact state of a tire on a wet road surface having an uneven surface corresponding to an actual road surface, non-patent document 1 proposes: a method of optically exciting fluorescence. According to the photo-excitation fluorescence method, when the thickness of the fluorescent liquid between the rubber test piece and the ground surface is small, the luminance is proportional to the thickness of the fluorescent liquid, and therefore, the measurement accuracy is excellent, and a measurement example in which the thickness is 10 μm or less is also confirmed.
However, even when the ground contact state of the tire in a stationary state on the uneven surface corresponding to the actual road surface is evaluated, there are: there is no problem of consistency with the evaluation of the tire contact state during running on an actual road surface.
Patent document 3 Japanese patent laid-open No. 2004-9880
Patent document 4 Japanese patent laid-open publication No. 2016-8950
Non-patent document 1: "light from methods を in" Konghoff, is performed in いたゴム areas of the world where the resolution of the contact portions, the possible viewing of the viewing area, と degrees ヒストグラム resolution- ", Nobuyshi OHNO, tribulogist 58, No. 10 (2013)763 to 772 pages
Disclosure of Invention
As for the evaluation method during running of a tire, patent document 2 discloses a method of imaging the ground contact shape of a tire while relatively moving the tire in the front-rear direction by bringing the tire into contact with a transparent plate having a liquid layer made of a white liquid provided on the surface, but the evaluation method using a colored liquid is similar to the above-mentioned patent document 1, and the evaluation accuracy is not sufficient. In addition, focusing mainly on obtaining a dynamic contour of a ground contact surface shape on a smooth glass plate, it is not assumed that a ground contact state in which irregularities occur randomly with an actual road surface is evaluated.
Even if tires having the same contact area on a wet road surface can be obtained, the friction coefficients for contributing to grip performance and the like are different, and the present inventors considered that it is necessary to know the characteristics of the ground contact state, not only the magnitude relation of the simple contact area. Further, it was found that the tire contact state can be evaluated with more excellent accuracy by evaluating the influence of other parameters based on the correlation between the tire contact area and the friction coefficient. For example, by selecting a state in which the contact areas are the same but the friction coefficients are in a magnitude relationship according to different experimental parameters and comparing the two states, it is possible to clarify the characteristics of the ground contact state in which the friction coefficient is high. However, it is expected that the difference between the two is small, and a highly accurate measurement method is required.
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a method for evaluating a tire contact state with high accuracy from a correlation between a tire contact area and a friction coefficient when running on a wet road surface.
Patent document 3 describes: patent document 4 describes an apparatus for measuring a ground contact shape of a tread surface of a tire during running, the apparatus including: an observation method capable of observing deformation of an elastic material such as rubber to which a slip angle is applied.
Further, patent document 5 describes a rubber friction test method in which a flat surface of a rubber test piece is pressed against: the test road surface including aggregate and simulating an actual road surface was measured for a load when a rubber test piece was moved in a straight line while sliding on a flat test road surface, and the coefficient of friction between the test road surface and the rubber test piece was measured.
However, the above does not evaluate the characteristics of the tire on a wet road surface, and therefore the above method cannot be directly applied to evaluation on a wet road surface. Patent document 5 merely measures the friction coefficient, and does not disclose a content of evaluating the correlation between the tire contact area and the friction coefficient when running on a wet road surface.
The tire ground contact state evaluation method according to the present invention includes the steps of: pressing a rubber test piece against a ground surface which is provided on one surface of a transparent plate and has irregularities corresponding to an actual road surface with a fluorescent liquid interposed therebetween, measuring a load when the rubber test piece is moved in a straight line while sliding, and measuring a friction coefficient between the ground surface and the rubber test piece; irradiating excitation light to the fluorescent liquid interposed between the ground surface and the rubber test piece from the opposite side of the transparent plate to the ground surface, and measuring the luminance distribution of fluorescence emitted from the fluorescent liquid; obtaining a 2-valued image by using the obtained brightness distribution as a reference and arbitrary brightness as a threshold value to obtain a contact area; the increase and decrease of the contact area are determined from the difference between 2 or more 2-valued images having different measurement parameters.
The different measurement parameters may be at least 1 selected from the group consisting of a measurement time, a moving speed of the rubber test piece, a hardness of the rubber test piece, a pressing force of the rubber test piece against the ground surface, and a shape of the rubber test piece.
Preferably, the fluorescent liquid may contain: and a hydrophilic fluorescent dye having a difference in peak wavelength between the excitation spectrum and the fluorescence spectrum of 100nm or more, wherein the hydrophilic fluorescent dye is trisodium hydroxypyrene trisulfonate.
The pH of the fluorescent liquid can be 5-8.
The method may further include: a step of converting the obtained brightness distribution into a film thickness distribution of the fluorescent liquid to obtain a film thickness distribution image, and a step of obtaining an increase or decrease in film thickness from a difference between 2 or more types of film thickness distribution images having different measurement parameters.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the evaluation method of the present invention, the tire contact state can be evaluated with high accuracy from the correlation between the tire contact area and the friction coefficient when running on a wet road surface.
Drawings
Fig. 1 is a schematic diagram showing an overall configuration of a testing machine that performs a tire contact state evaluation method according to an embodiment.
Fig. 2 is a schematic diagram showing a configuration of a fluorescence measuring apparatus for performing the tire contact state evaluation method according to the embodiment.
FIG. 3 is a schematic diagram showing the relationship between the excitation spectrum and the fluorescence spectrum in the case where trisodium hydroxypyrene trisulfonate is used as a fluorescent dye.
Description of the reference numerals
A transparent plate; a rubber test piece; a bracket; a load device; a drive device; a load sensor; a control device; a table; an actuator; a testing machine; fluorescent liquid; a light source; a photographing unit; a dichroic mirror; a reflector; an optical filter; an optical filter; a transparent plate setting table; a fluorescence assay device.
Detailed Description
Next, a tire contact state evaluation method according to an embodiment of the present invention will be described with reference to fig. 1 to 3.
The tire contact state evaluation method of the present embodiment includes the steps of: pressing a rubber test piece against a ground surface which is provided on one surface of a transparent plate and has irregularities corresponding to an actual road surface with a fluorescent liquid interposed therebetween, measuring a load when the rubber test piece is moved in a straight line while sliding, and measuring a friction coefficient between the ground surface and the rubber test piece; irradiating excitation light to the fluorescent liquid interposed between the ground surface and the rubber test piece from the opposite side of the transparent plate from the ground surface, and measuring the luminance distribution of fluorescence emitted from the fluorescent liquid; obtaining a 2-valued image by using the obtained luminance distribution as a reference and arbitrary luminance as a threshold value to obtain a contact area; and determining an increase or decrease in the contact area based on a difference between 2 or more 2-valued images having different measurement parameters.
Fig. 1 is a schematic diagram showing the overall configuration of a testing machine that performs the tire contact state evaluation method according to the present embodiment.
The testing machine 10 includes: a transparent plate 1 having a ground plane on one surface, the ground plane having a concave-convex surface equivalent to an actual road surface (or an actual road equivalent surface); a holder 3 for holding the rubber test piece 2; a load device 4 for pressing the rubber test piece 2 against the transparent plate 1; a driving device 5 for relatively moving the rubber test piece 2 with respect to the transparent plate 1; a load sensor 6 for measuring a load acting on the rubber test piece 2; and a control device 7 for controlling the operation required for the test. The transparent plate 1 is disposed above the transparent plate mounting table 18, and the fluorescence measuring device 20 is disposed below the transparent plate mounting table 18.
The method for producing the transparent plate 1 having the ground surface provided with the irregularities on the actual road surface is not particularly limited, and for example, the transparent plate can be produced by molding a silicon mold for vacuum casting with silicone rubber from asphalt corresponding to the actual road surface, pouring a transparent resin into the mold, and curing the mold in a vacuum degassed state. The transparent resin may be, for example, a polyurethane resin.
The rubber test piece 2 may be made of vulcanized rubber, and has: the flat surface pressed against the transparent plate 1 may include: grooves and cones corresponding to the tire grooves.
The carrier 3 is connected to a load device 4. The load device 4 is configured to: the carriage 3 is made to be capable of reciprocating in a Z direction (vertical direction in fig. 1) perpendicular to the transparent plate 1. By appropriately setting the position of the bracket 3 (the distance between the bracket 3 and the transparent plate 1), the Z-direction load input to the rubber test piece 2 can be adjusted, and therefore the rubber test piece 2 can be pressed against the transparent plate 1 under a predetermined pressure condition. The load device 4 is constituted by a servo motor, but other actuator mechanisms may be used.
The driving device 5 is configured to: the table 8 supporting the load device 4 is made to be capable of reciprocating in the X direction (the left-right direction in fig. 1). The carriage 3 is moved by the movement of the table 8, and the rubber test piece 2 can be moved while sliding on the transparent plate 1. The actuator 9 is constituted by: the table 8 is made to reciprocate in a Y direction (a direction perpendicular to the paper surface in fig. 1) perpendicular to both the X direction and the Z direction, and is used for positioning the rubber test piece 2 and the transparent plate 1 in the Y direction. In the present embodiment, the drive device 5 and the actuator 9 are each constituted by a servo motor, but the present invention is not limited thereto.
The load sensor 6 can measure a load having three components in total, i.e., a vertical component and a horizontal component, and can measure a load (vertical force) in the Z direction, a load (front-rear force) in the X direction, and a load (lateral force) in the Y direction, which act on the rubber test piece 2. The load sensor 6 is constituted by a load cell, for example. In the present embodiment, a load sensor 6 is attached to the upper side of the bracket 3 (the side opposite to the rubber test piece 2).
The control device 7 includes: a calculation unit 7a for performing calculation necessary for measuring the friction coefficient; an operation control unit 7b that controls operations of the load device 4, the drive device 5, and the like; an input unit 7c that receives an input from a test operator; and a display unit 7d for displaying various information related to the operation, setting, and the like of the testing machine 10 on the screen. The measurement value obtained by the load sensor 6 is sent to the control device 7, and the calculation unit 7a calculates the friction coefficient based on the measurement value.
As shown in fig. 2, the following components are disposed as the fluorescence measuring device 20 below the transparent plate installation table 18: a light source 12; a filter 16 that transmits and separates only light of a specific wavelength from the light emitted from the light source 12; a dichroic mirror 14 that reflects only light of a specific wavelength; a reflecting mirror 15 that reflects the fluorescence emitted from the fluorescent liquid 11; a filter 17 for separating only light of a specific wavelength from the emitted fluorescence; and an imaging unit 13 for measuring the fluorescence transmitted through the filter 17.
The fluorescence measuring device 20 may be fixed to a lower portion of the transparent plate installation table 18, and may be configured such that: is supported by the table 8 and is capable of reciprocating in the X direction in conjunction with the load device 4 by the drive device 5.
The tire contact state evaluation method according to the present embodiment can be performed in the following manner using the above-described tester 10, for example, trisodium hydroxypyrene trisulfonate (ピラニン) as a hydrophilic fluorescent dye. That is, the fluorescent liquid 11 containing trisodium hydroxypyrene trisulfonate was interposed between the transparent plate 1 having irregularities corresponding to an actual road surface, and then the flat surface of the rubber test piece 2 was pressed, and the load when the rubber test piece 2 was moved straight while sliding on the transparent plate 1 was measured, and the friction coefficient between the transparent plate 1 and the rubber test piece 2 was measured. The coefficient of static friction and the coefficient of dynamic friction can be measured. The pressure condition of the rubber test piece 2 pressed against the transparent plate 1 and the conditions relating to the straight movement such as the speed and the path are controlled by the control device 7. The moving speed may be set as: the rubber test piece 2 was slid at the same speed in a predetermined interval.
At this time, excitation light is irradiated using an ultraviolet LED (peak wavelength 365nm) as the light source 12, and the excitation light having a wavelength of 400nm or less is separated by the filter 16(400nm low pass filter). The separated excitation light is reflected by the dichroic mirror 14, and the excitation light is irradiated from the side opposite to the ground surface of the transparent plate 1 toward the fluorescent liquid 11 interposed between the rubber test piece 2 and the ground surface, whereby the trisodium hydroxypyrene trisulfonate contained in the fluorescent liquid 11 is transited from the basic state to the excitation state. Then, the trisodium hydroxypyrene trisulfonate in the excited state returns to the base state again, and fluorescence is released. The emitted fluorescence is transmitted through the dichroic mirror 14, reflected by the reflecting mirror 15, and separated by the filter 17(480nm bypass filter) into fluorescence having a wavelength of 480nm or longer. The separated fluorescence is imaged by the imaging unit 13, whereby a luminance distribution (fluorescence intensity image) can be obtained.
The tire contact state evaluation method of the present embodiment further includes the steps of: the luminance distribution obtained as described above is used as a reference, and an arbitrary luminance is set to 2 values as a threshold. Specifically, by setting a certain specific luminance as a threshold, a region having a luminance equal to or lower than the threshold can be used as a region where the rubber test piece 2 and the ground surface come into contact with each other, and a 2-valued image can be obtained. From such a 2-valued image, for example, the area where the rubber test piece 2 actually contacts the ground surface can be calculated.
By performing the above test, it is possible to simultaneously obtain: the correlation between the coefficient of friction on the wet road surface and the 2-valued image showing the ground contact state between the wet road surface and the rubber test piece 2 can be obtained.
The tire contact state evaluation method according to the present embodiment further includes, in addition to the above steps: and a step of obtaining an increase/decrease in the contact area from a difference between 2 or more 2-valued images having different measurement parameters. By determining the increase or decrease in the contact area from the difference of the 2-valued images, the influence of the measurement parameter on the ground contact state can be evaluated. For example, when there is a 2-valued image having the same contact area but a different friction coefficient, the feature of the ground contact state having a high friction coefficient can be clarified by comparing the two images. In addition, 2 or more kinds of 2-valued images are processed with the same threshold value.
Examples of the measurement parameters include: the measurement time, the moving speed of the rubber test piece 2, the hardness of the rubber test piece 2, the pressure with which the rubber test piece 2 is pressed against the ground surface, the shape of the rubber test piece 2, and the like. That is, 2 or more kinds of 2-valued images having different measurement parameters may be obtained by comparing 2-valued images having different measurement times obtained in one test with each other, or by comparing 2-valued images obtained in different tests performed by changing measurement parameters such as the moving speed of the rubber test piece 2, the hardness of the rubber test piece 2, the pressing force of the rubber test piece 2 against the ground surface, and the shape of the rubber test piece 2 with each other.
In the above embodiment, the case where trisodium hydroxypyrene trisulfonate is used as the hydrophilic fluorescent dye was described, but the present invention is not limited thereto. Various hydrophilic fluorescent dyes can be used for the fluorescent liquid 11, but from the viewpoint of obtaining excellent measurement accuracy, an aqueous solution containing a hydrophilic fluorescent dye whose difference between the peak wavelengths of the excitation spectrum and the fluorescence spectrum is 100nm or more is preferable. Specific examples of the hydrophilic fluorescent dye having a difference in peak wavelength between the excitation spectrum and the fluorescence spectrum of 100nm or more include: trisodium hydroxypyrene trisulfonate, DY-481XL-Carboxylic Acid manufactured by Dyomics, DY-521XL-Carboxylic Acid, ATTO 490LS carboxy manufactured by ATTO-TEC, and the like, and trisodium hydroxypyrene trisulfonate can be preferably used from the viewpoints of safety and cost. In the case where there are a plurality of hydrophilic fluorescent dyes having peak wavelengths in the excitation spectrum and/or the fluorescence spectrum, the peak wavelength may be selected and used by using a filter or the like so that the difference in peak wavelength between the excitation spectrum and the fluorescence spectrum is 100nm or more.
Trisodium hydroxypyrene trisulfonate is a hydrophilic pH-sensitive fluorescent dye, and when the liquid is neutral to acidic, the peak wavelengths of the excitation spectra appear near 365nm and near 400nm, and when the liquid is basic, the peak wavelength of the excitation spectra appears near 450 nm. The peak wavelength of the fluorescence spectrum is mainly around 510nm regardless of the liquid properties, and almost no fluorescence spectrum of 400nm or less is detected. Therefore, when trisodium hydroxypyrene trisulfonate is used as the hydrophilic fluorescent dye, the liquid property of the fluorescent liquid 11 is preferably neutral to acidic, and the pH is preferably 5 to 8, from the viewpoint of making the difference in peak wavelength between the excitation spectrum and the fluorescence spectrum 100nm or more. In the present embodiment, the filter 16 that transmits only a wavelength of 400nm or less is used for the excitation light, and thus the peak wavelength of the excitation spectrum of trisodium hydroxypyrene trisulfonate is mainly 365nm, and the difference in the peak wavelength between the excitation spectrum and the fluorescence spectrum is 145nm at the maximum.
As shown in fig. 3, by using a fluorescent dye having a difference in peak wavelength between an excitation spectrum and a fluorescence spectrum of 100nm or more as the fluorescent liquid 11, the excitation spectrum and the fluorescence spectrum can be sufficiently separated from each other with almost no overlapping of wavelength regions between the excitation spectrum and the fluorescence spectrum, and thus, excellent measurement accuracy can be easily obtained.
Although the concentration of the hydrophilic fluorescent dye in the fluorescent liquid is not particularly limited, when trisodium hydroxypyrene trisulfonate is used, the concentration is preferably 100 to 10000 mg/L.
The light source 12 may be appropriately selected and used in accordance with the excitation spectrum of the hydrophilic fluorescent dye to be used, and is preferably, but not particularly limited to: the light source 12 having a peak wavelength in the vicinity of the peak wavelength of the excitation spectrum of the hydrophilic fluorescent dye to be used is more preferably a single wavelength. When the hydrophilic fluorescent dye is trisodium hydroxypyrene trisulfonate, the peak wavelength of the irradiated light is preferably 350 to 400 nm.
The dichroic mirror 14 and the filters 16 and 17 are not particularly limited, and may be appropriately selected and used according to the excitation spectrum and the fluorescence spectrum of the hydrophilic fluorescent dye to be used. Examples of the filters 16 and 17 include: a wavelength-selective fluorescent filter that removes noise at the time of fluorescence detection, a bypass filter (long pass filter) that cuts (cut) light on the short wavelength side shorter than a predetermined wavelength and transmits light on the long wavelength side, a low-pass filter (short pass filter) that cuts (cut) light on the long wavelength side longer than the predetermined wavelength and transmits light on the short wavelength side, a band-pass filter (short pass filter) that transmits only light in a constant wavelength region and cuts (cut) light on the other short wavelength side and long wavelength side, and the like.
The tire contact state evaluation method according to the present embodiment may further include: a step of converting the obtained brightness distribution into a film thickness distribution of the fluorescent liquid 11 to obtain a film thickness distribution image, and a step of obtaining an increase or decrease in film thickness from a difference between 2 or more types of film thickness distribution images having different measurement parameters. For the rubber having high water drainage, it is considered that: since the film thickness of the fluorescent liquid 11 existing between the rubber and the road surface unevenness becomes thin, it can be predicted that: contributing to an increase in the coefficient of friction. Therefore, by comparing the film thickness distribution images of 2 or more types having different measurement parameters, it is possible to determine the increase or decrease in the film thickness of the fluorescent liquid 11 existing between the rubber-road surface irregularities under the friction condition, thereby making it possible to evaluate the contribution of the water drainage property and the film thickness to the friction coefficient, and to evaluate the ground contact state in more detail. When the fluorescent liquid 11 between the rubber test piece 2 and the ground surface has a small film thickness, the luminance is proportional to the film thickness, and therefore, the luminance distribution obtained can be converted into a film thickness distribution by converting the luminance after the numerical conversion into the film thickness. In addition, as a preliminary step to this step, the luminance and the film thickness may be corrected. For example, the fluorescent liquid 11 is filled in: the brightness can be converted into the film thickness by obtaining a calibration curve of the film thickness and the brightness by combining glass plates having known dimensions to form a space, and applying the calibration curve. This can be applied even when there is no proportional relationship between the luminance and the film thickness.
Although the embodiments of the present invention have been described, the above embodiments are only illustrated as examples and are not intended to limit the scope of the invention. The above-described new embodiment can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.
Industrial applicability
The tire contact patch state evaluation method of the present invention can be used for evaluation of contact patch states of various tires for passenger vehicles, light trucks, buses, and the like.
Claims (6)
1. A tire ground contact state evaluation method is characterized in that,
it includes:
pressing a rubber test piece against a ground surface which is provided on one surface of the transparent plate and has irregularities corresponding to an actual road surface with a fluorescent liquid interposed therebetween, measuring a load when the rubber test piece is moved in a straight line while sliding, and measuring a friction coefficient between the ground surface and the rubber test piece;
irradiating excitation light to the fluorescent liquid interposed between the ground surface and the rubber test piece from the opposite side of the transparent plate from the ground surface, and measuring the luminance distribution of fluorescence emitted from the fluorescent liquid;
obtaining a 2-valued image by using the obtained luminance distribution as a reference and arbitrary luminance as a threshold value, and obtaining a contact area; and
a step of obtaining an increase or decrease in the contact area from a difference between 2 or more kinds of 2-valued images having different measurement parameters,
the fluorescent liquid contains: a hydrophilic fluorescent dye having a difference in peak wavelength between an excitation spectrum and a fluorescence spectrum of 100nm or more.
2. The tire ground contact state evaluation method according to claim 1,
the measurement parameter is at least 1 selected from the group consisting of a measurement time, a moving speed of the rubber test piece, a hardness of the rubber test piece, a pressing force of the rubber test piece against the ground surface, and a shape of the rubber test piece.
3. The tire ground contact state evaluation method according to claim 1 or 2,
the hydrophilic fluorescent pigment is trisodium hydroxypyrene trisulfonate.
4. The tire ground contact state evaluation method according to claim 3,
the pH value of the fluorescent liquid is 5-8.
5. The tire ground contact state evaluation method according to claim 1 or 2,
further comprising:
converting the obtained brightness distribution into a film thickness distribution of the fluorescent liquid to obtain a film thickness distribution image;
and a step of determining increase and decrease of the film thickness from a difference between the film thickness distribution images of 2 or more types having different measurement parameters.
6. The tire ground contact state evaluation method according to claim 3,
further comprising:
converting the obtained brightness distribution into a film thickness distribution of the fluorescent liquid to obtain a film thickness distribution image;
and a step of determining increase and decrease of the film thickness from a difference between the film thickness distribution images of 2 or more types having different measurement parameters.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2017198661A JP7017899B2 (en) | 2017-10-12 | 2017-10-12 | Tire ground contact condition evaluation method |
| JP2017-198661 | 2017-10-12 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109655287A CN109655287A (en) | 2019-04-19 |
| CN109655287B true CN109655287B (en) | 2020-12-08 |
Family
ID=66110676
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811035726.3A Active CN109655287B (en) | 2017-10-12 | 2018-09-06 | Tire grounding state evaluation method |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP7017899B2 (en) |
| CN (1) | CN109655287B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115015103B (en) * | 2022-05-24 | 2023-01-03 | 武汉中誉鼎力智能科技有限公司 | Real-time detection method and device for friction factor and microscopic morphology of material surface |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003240681A (en) * | 2002-02-20 | 2003-08-27 | Bridgestone Corp | Tire grounding characteristic evaluating method |
| WO2009116359A1 (en) * | 2008-03-17 | 2009-09-24 | 国立大学法人東京農工大学 | Contact area measurement device and method for measuring contact area |
| CN101668672A (en) * | 2007-04-27 | 2010-03-10 | 株式会社普利司通 | Tire grounding state estimating method, tire grounding state estimating device, and grounding state estimating tire |
| JP2012154858A (en) * | 2011-01-27 | 2012-08-16 | Bridgestone Corp | Method and apparatus for measuring shape of tire |
| CN104471367A (en) * | 2012-07-20 | 2015-03-25 | 株式会社普利司通 | Tire contact properties measurement method and measurement device |
| CN105209879A (en) * | 2013-04-17 | 2015-12-30 | 天一系统 | Module for testing active contact pressure of tire, and tire testing apparatus using same |
| CN106525137A (en) * | 2016-12-07 | 2017-03-22 | 天津大学 | Liquid film temperature field and flow field simultaneous measurement method based on laser induced fluorescence |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009085621A (en) * | 2007-09-27 | 2009-04-23 | Sumitomo Rubber Ind Ltd | Measuring tool of tire grounding part |
| JP6594715B2 (en) * | 2015-09-16 | 2019-10-23 | Ｔｏｙｏ Ｔｉｒｅ株式会社 | Rubber friction test method |
-
2017
- 2017-10-12 JP JP2017198661A patent/JP7017899B2/en active Active
-
2018
- 2018-09-06 CN CN201811035726.3A patent/CN109655287B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003240681A (en) * | 2002-02-20 | 2003-08-27 | Bridgestone Corp | Tire grounding characteristic evaluating method |
| CN101668672A (en) * | 2007-04-27 | 2010-03-10 | 株式会社普利司通 | Tire grounding state estimating method, tire grounding state estimating device, and grounding state estimating tire |
| WO2009116359A1 (en) * | 2008-03-17 | 2009-09-24 | 国立大学法人東京農工大学 | Contact area measurement device and method for measuring contact area |
| JP2012154858A (en) * | 2011-01-27 | 2012-08-16 | Bridgestone Corp | Method and apparatus for measuring shape of tire |
| CN104471367A (en) * | 2012-07-20 | 2015-03-25 | 株式会社普利司通 | Tire contact properties measurement method and measurement device |
| CN105209879A (en) * | 2013-04-17 | 2015-12-30 | 天一系统 | Module for testing active contact pressure of tire, and tire testing apparatus using same |
| CN106525137A (en) * | 2016-12-07 | 2017-03-22 | 天津大学 | Liquid film temperature field and flow field simultaneous measurement method based on laser induced fluorescence |
Non-Patent Citations (2)
| Title |
|---|
| Measurement ofrealcontactareaandanalysisofstick/slipregion;Masao Eguchi;《TribologyInternational》;20090512;第1781-1791页 * |
| 子午线轮胎静态及滚动状态下接地特性试验研究;王国林;《橡胶工业》;20160731;第63卷(第7期);第425-428页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2019074335A (en) | 2019-05-16 |
| CN109655287A (en) | 2019-04-19 |
| JP7017899B2 (en) | 2022-02-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101108250B1 (en) | Measuring apparatus for tire wear | |
| US7984646B2 (en) | Method of measuring the three-dimensional profile of a ground, and device for implementing said method | |
| JP5833317B2 (en) | Tire shape measuring method and tire shape measuring apparatus | |
| CN109655287B (en) | Tire grounding state evaluation method | |
| KR20120055071A (en) | State inspection apparatus and method for automobile tire | |
| JP2006242674A (en) | Light section measuring device and emission line image imaging apparatus | |
| KR20130134394A (en) | Inspection device of tire tread using machine vision and inspection method thereof | |
| KR20190088302A (en) | Car tire monitoring device | |
| CN107548448B (en) | Calculation of layer thickness | |
| Sakai | Measurement and visualization of the contact pressure distribution of rubber disks and tires | |
| JPH10176907A (en) | Method for evaluating tire tread abrasion | |
| Isomaa et al. | Onset of frictional sliding in rubber–ice contact | |
| CN102538683B (en) | Optical imaging method for measuring distance smaller than diffraction limit distance | |
| EP2861969A2 (en) | Apparatus, system, and method for image normalization using a gaussian residual of fit selection criteria | |
| JP6271188B2 (en) | Evaluation method of road surface properties of paved roads | |
| JP6215007B2 (en) | Wear evaluation method and wear tester for tire rubber | |
| CN1239546A (en) | Diagnostic method and device for degenerated oil | |
| JP6444720B2 (en) | Wear evaluation method and wear tester for tire rubber | |
| EP1098166A2 (en) | Method and apparatus for thickness measurement on transparent films | |
| KR100765394B1 (en) | Hydroplaning measuring apparatus of tire | |
| CN109269928A (en) | A kind of tire wear testing machine and its detection method | |
| JP6815842B2 (en) | Tire contact condition measurement method | |
| JP7294794B2 (en) | Polishing pad with pad wear indicator | |
| CN106414195A (en) | Method for testing brake systems of motor vehicles | |
| JP5794931B2 (en) | Tire evaluation method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |