JP4088889B2 - Tire contact surface measuring device and tire contact surface measuring method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tire contact surface measuring device and a tire contact surface measuring method capable of photographing a tire contact surface with respect to an ice road surface, and is particularly useful for measuring a contact shape of a studless tire.
[0002]
[Prior art]
Since the ground contact shape of a tire has a great influence on the tire performance such as steering stability, noise, and riding comfort, measurement of the ground contact shape and its quantification are regarded as important. However, since it is assumed that studless tires are used on ice road surfaces, the friction coefficient of which is significantly lower than that of normal road surfaces, the ground contact shape on the ice road surface that reproduces the actual usage conditions is assumed when developing the studless tire. Understanding is required.
[0003]
On the other hand, as a method of observing the ground contact shape of the tire, there are a method of observing while rotating the tire and a method of observing with the tire stationary, and the former method from the viewpoint of reproducing the actual use situation Is considered effective. Furthermore, as a method of rotating the tire, a method of observing from a pit below the road surface in the course using an actual vehicle, a method of moving a flat road surface while freely rotating the tire, and the like are known.
[0004]
Specifically, as a method of using an actual vehicle, a water film of an aqueous solution of a pigment is formed on a transparent plate, and the tire ground contact shape is photographed from below the road surface when the actual vehicle tire passes on the transparent plate. A method is known (see, for example, Patent Document 1). According to this method, since the pigment is used, there is an advantage that the outline of the tire ground contact shape becomes clear.
[0005]
[Patent Document 1]
JP 2001-208653 A (2nd page, FIG. 1)
[Non-Patent Document 1]
Takashi Takagi et al. “Research on modeling of tires for automobiles” published by the Society of Automotive Engineers of Japan, Academic Lecture Preprint, May 1997 (6th page, FIGS. 12-14).
[0006]
[Problems to be solved by the invention]
However, in the method of Patent Document 1, when an aqueous pigment solution is used on the ice road surface, the ice road surface (usually almost no moisture is present) cannot be properly reproduced. For this reason, the ice road surface is reproduced to observe the ground contact shape. I couldn't. Further, when an ice layer is formed on a transparent plate and observed without using an aqueous pigment solution, there is a problem that the outline of the tire ground contact shape becomes unclear.
[0007]
On the other hand, Non-Patent Document 1 describes a method of moving a flat road surface while freely rotating a tire and photographing a tire ground contact shape from below an acrylic plate provided on the flat road surface. At this time, it is described that when light is incident from the side surface of the acrylic plate, the luminance is changed by the contact surface pressure, and thereby the distribution of the contact surface pressure can be known.
[0008]
However, this method has a problem that since the long flat road surface is moved, the tire ground contact shape can be observed only at an extremely low speed. In addition, there is no mention of observation of the tire ground contact shape assuming an ice road surface.
[0009]
Accordingly, an object of the present invention is to provide a tire contact surface measurement device and a tire contact surface measurement method that can accurately photograph the contour of a tire contact surface shape with respect to an ice road surface, and preferably measure at a speed close to actual driving. There is.
[0010]
[Means for Solving the Problems]
The above object can be achieved by the present invention as described below.
That is, the tire ground contact surface measuring device of the present invention comprises a transparent plate having an ice layer formed on the surface thereof, a light irradiating means for irradiating the transparent plate and / or the inside of the ice layer with light substantially parallel thereto, And a photographing means for photographing the tire ground contact surface from the opposite side of the ice layer.
[0011]
According to the tire contact surface measuring apparatus of the present invention, since the transparent plate having the ice layer formed on the surface is provided, the tire contact shape with respect to the ice road surface can be photographed by the photographing means through the transparent plate. At this time, since the transparent plate and / or the light irradiating means for irradiating light substantially parallel to the inside of the ice layer is provided, the light totally reflected inside the ice layer or the like is transmitted only at the interface where the tire is grounded. Due to this phenomenon, the contour of the tire ground contact shape can be accurately photographed. This phenomenon will be described with reference to FIGS. Conventionally, as shown in FIG. 1 (b), light is irradiated by the light irradiation means 5 from the side where the photographing means 6 is arranged. In this method, the irradiated light passes through the transparent plate 1 and the ice layer 2. Since the transmitted light is reflected by the tire 3 and again passes through the transparent plate 1 and the ice layer 2 and reaches the photographing means 6, the amount of light reflected not only at the ground contact interface 3 a of the tire 3 but also at the periphery thereof does not change. Therefore, the outline of the ground contact shape could not be clearly photographed. On the other hand, in the present invention, as shown in FIG. 1 (a), the light irradiation means 5 is used to irradiate the inside of the ice layer 2 with light substantially parallel thereto, so that the refractive index of air and ice is reduced. Due to the difference, the light is totally reflected inside the ice layer 2, and the light does not go outside except the ground interface 3 a of the tire 3. At this time, since the refractive index of rubber and the refractive index of ice are close to each other at the ground contact interface 3a of the tire 3, light is transmitted to the tire side. This is reflected by the tire 3 and again passes through the transparent plate 1 and the ice layer 2 to reach the photographing means 6, so that the grounding interface 3a of the tire 3 and its surroundings are photographed with different amounts of light. The outline can be clearly photographed. FIG. 3 shows a still photograph of the tire contact surface photographed by the tire contact surface measuring device of the present invention (light irradiation is inside the ice layer), and the contour of the contact shape is clear.
[0012]
In addition, since there is no air at the interface between the transparent plate 1 and the ice layer 2, total reflection is unlikely to occur. Therefore, even when light that is substantially parallel to the inside of the transparent plate or the transparent plate and the ice layer is irradiated, The same effect as described above can be obtained.
[0013]
In the above, the transparent plate further includes at least a part of a cylindrical portion, and further includes a rotary drum that can be driven to rotate, and a tire grounding means that can ground the tire in a rotating state on the inner surface side of the cylindrical portion. preferable. According to this apparatus, the ground contact state of the tire during vehicle travel can be reproduced by rotating the cylindrical portion while grounding the tire on the inner surface side of the cylindrical portion of the rotary drum by the tire ground contact means. At this time, the contact surface of the tire that contacts the ice layer formed on the surface of the tire can be photographed through the transparent plate forming a part of the cylindrical portion.
[0014]
The transparent plate further comprises at least a part of a cylindrical part, and a rotary drum capable of being driven to rotate, and a sample grounding means capable of supporting a tread sample of a tire on the inner surface of the cylindrical part in a grounded state. It may be. According to this apparatus, the ground contact state of the tire in the slip state can be reproduced by supporting the tread sample on the inner surface of the cylindrical portion by the sample grounding means while rotating the cylindrical portion of the rotary drum. At this time, the contact surface of the tire that contacts the ice layer formed on the surface of the tire can be photographed through the transparent plate forming a part of the cylindrical portion.
[0015]
The transparent plate is provided in a part of the cylindrical portion in the circumferential direction, and the photographing means photographs a still image in response to a sent signal, and further detects a rotational position of the rotary drum. It is preferable that the apparatus further comprises position detecting means for sending a signal for determining the photographing timing to the photographing means.
[0016]
Considering the strength and durability of the rotary drum, it is desirable to provide the transparent plate in a part of the cylindrical portion in the circumferential direction. However, when taking a still image, it is necessary to take an image with good timing. Therefore, a still image can be taken with good timing by providing the position detecting means for detecting the rotational position and sending the signal for determining the shooting timing as described above.
[0017]
On the other hand, the tire contact surface measurement method of the present invention includes a transparent plate on which an ice layer is formed, a light irradiating means for irradiating the transparent plate and / or the inside of the ice layer with light substantially parallel thereto, A photographing means for photographing the tire ground contact surface from the opposite side of the ice layer, a rotary drum in which the transparent plate forms at least a part of the cylindrical portion and which can be driven to rotate, and the tire is rotated to the inner surface side of the cylindrical portion. After forming an ice layer on the inner peripheral surface of the cylindrical portion of the rotary drum, using a tire ground contact surface measuring device equipped with a tire ground contact means capable of ground contact in a state, while irradiating light by the light irradiation means, While the rotary drum is driven to rotate, the photographing means photographs a tire ground contact surface through a transparent plate.
[0018]
According to this tire contact surface measurement method, since an ice layer is formed on the inner peripheral surface of the cylindrical portion of the rotary drum, it is possible to photograph the tire contact shape with respect to the ice road surface through the transparent plate. At this time, since the transparent plate and / or the light irradiating means for irradiating light substantially parallel to the inside of the ice layer is provided, the light totally reflected inside the ice layer or the like is transmitted only at the interface where the tire is grounded. Due to this phenomenon, the contour of the tire ground contact shape can be accurately photographed. At that time, the ground contact state of the tire during traveling of the vehicle can be reproduced by rotating the cylindrical portion while grounding the tire on the inner surface side of the cylindrical portion of the rotary drum by the tire ground contact means.
[0019]
In the above, it is preferable that the tire contact surface is photographed while applying a braking force or a driving force to the tire. Thereby, the ground contact state of the tire in the braking state and the drive state of the vehicle can be reproduced, and the contour of the tire ground contact shape at that time can be accurately photographed.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig.1 (a) is a figure which shows the principal part of the tire contact surface measuring device of this invention, and FIG. 2 is a schematic block diagram which shows an example of the tire contact surface measuring device of this invention.
[0021]
As shown in FIG. 1 (a), the tire ground contact surface measuring device of the present invention has a transparent plate 1 having an ice layer 2 formed on the surface thereof, and the transparent plate 1 and / or the ice layer 2 inside. The light irradiation means 5 which irradiates parallel light, and the imaging | photography means 6 which image | photographs a tire ground-contact surface from the other side of the said ice layer 2 are provided. In the present embodiment, as shown in FIG. 2, a rotary drum 10 having a cylindrical portion 11 that can be rotationally driven, and a tire grounding means 20 that can ground a tire on the inner surface side of the cylindrical portion 11 in a rotating state. An example of an apparatus further comprising:
[0022]
Although the transparent plate 1 should just be provided in at least one part of the circumferential direction of the cylindrical part 11, when the whole intensity | strength and durability are considered, providing in a part of the circumferential direction of the cylindrical part 11 is preferable. The width for providing the transparent plate 1 may be larger than the width of the ground contact interface 3 a of the tire 3.
[0023]
The transparent plate 1 may be either colorless and transparent or colored and transparent, but it is preferable to use a colorless and transparent one. Moreover, it has a certain amount of strength, and the refractive index n _D of the transparent plate 1 is preferably close to the refractive index n _{D of} ice (about 1.3), and the refractive index n _D is 1.3 to 1.55. Those are preferred. Examples of the transparent plate 1 include inorganic glass plates such as tempered glass, plastic plates such as polyvinyl chloride, polystyrene, acrylic resin, and polycarbonate, inorganic crystal plates, and the like. The thickness of the transparent plate 1 is preferably 20 to 50 mm for total reflection while ensuring a certain level of strength.
[0024]
The ice layer 2 is preferably formed on the surface of the transparent plate 1 without interposing air. The surface of the ice layer 2 is preferably a flat surface with no irregularities. In order to form such a surface, it is effective to form the ice layer 2 while slowly rotating the cylindrical portion 11 of the rotary drum 10. Annular walls standing on the inner periphery are provided on both sides of the cylindrical part 11, and water before becoming ice accumulates on the inner surface of the cylindrical part 11 by the annular wall.
[0025]
When the tire ground contact surface is photographed while the rotary drum 10 is rotated, the surface of the ice layer 2 is shaved and uneven. For this reason, when photographing the tire ground contact surface of another tire in succession, it is desirable to cut the surface ice to make it flat. Therefore, the tire contact surface measuring device of the present invention preferably further includes a cutting means (not shown) for flattening the ice layer 2 formed on the inner peripheral surface of the cylindrical portion 11 of the rotary drum 10. The cutting means includes a rotary cutting blade, a polishing belt, a polishing cloth, and the like, and preferably has a suction device that sucks the cut ice pieces.
[0026]
In the present embodiment, the light irradiation means 5 (not shown in FIG. 2) disposed opposite to the side surface of the ice layer portion 2a located on the inner surface of the transparent plate 1 is used, and the inside thereof is substantially parallel to the ice layer portion 2a. Irradiate light. In the present invention, at least one of the transparent plate 1 and the ice layer 2 may be irradiated. As the light irradiating means 5, a fluorescent lamp, an LED, a light bulb or the like provided with a reflecting plate 5a for controlling the emission direction, a lens, or the like can be used.
[0027]
The annular wall as described above is provided on the side surface of the ice layer portion 2a. By forming at least a part thereof with a transparent body, light can be irradiated from the side surface of the ice layer portion 2a. In the present invention, a part of the light from the light irradiation means 5 may directly irradiate the tire 3. In this case, the light reflected by the tire 3 is photographed by the photographing means 6, but the reflection from the tire 3 by the light from the side surface is white (high brightness), and the reflection from the ground interface 3 a with the ice layer 2. Therefore, the contour of the ground contact shape can be clearly distinguished.
[0028]
The photographing means 6 is arranged at a position where the tire contact surface can be photographed via the transparent plate 1 from the opposite side of the ice layer 2. As the photographing means 6, a CCD camera, a video camera, a high-speed camera or the like can be used, but a CCD camera (including a digital camera) is effective when photographing a still image. The CCD camera is generally connected to the personal computer 8 via an image input board, and the shooting timing of still images can be directly controlled by signals from the CCD camera. In this embodiment, the CCD camera and the personal computer 8 constitute a photographing means.
[0029]
Although the photographing unit 6 may continuously shoot moving images, the present embodiment shows an example in which a still image is photographed as the photographing unit 6 in accordance with a transmitted signal. The captured image data is taken into the personal computer 8 via an image input board or the like as necessary, and the contour, area, etc. of the ground contact shape can be digitized based on this image data.
[0030]
When shooting a rolling image, it is preferable to include position detection means 7 for detecting the rotational position of the rotary drum 10 and sending a signal for determining the shooting timing to the imaging means 6. In the present embodiment, an example is shown in which the signal from the position detection means 7 is sent directly to the personal computer 8, but a signal (trigger signal) for determining the shooting timing is sent to a relay box (not shown) of the CCD camera. Thus, photographing with a CCD camera may be performed. Further, the light irradiation by the light irradiation means 5 may be performed in accordance with the photographing timing.
[0031]
As the position detecting means 7, it is only necessary to detect the rotational position of the rotary drum 10, and any device using an optical sensor, a magnetic sensor, a contact sensor, or the like can be used. For example, a light shielding plate is provided at one location on the outer peripheral surface of the cylindrical portion 11 of the rotary drum 10, and the rotational position of the rotary drum 10 can be detected by passing through a photo interrupter (photo coupler).
[0032]
With such a signal, it is possible to control the shooting time of the rolling image with a signal from the personal computer 8.
[0033]
The rotary drum 10 may be in any device form as long as it includes a support mechanism and a drive mechanism capable of rotationally driving the cylindrical portion 11. In the illustrated example, the rotating shaft 12 of the cylindrical portion 11 is cantilevered, and the cylindrical portion 11 is rotationally driven by the drive mechanism 13 provided on the base 14.
[0034]
The tire grounding means 20 may include a tire 3 or a wheel mounting portion, and may simply ground the tire 3 on the inner surface side of the cylindrical portion 11 in a rotating state. In the present invention, the tire ground contact means 20 preferably has a drive mechanism or a brake mechanism so that a braking force or a driving force can be applied to the tire 3. Examples of the driving mechanism include an electric motor, and examples of the braking mechanism include a method of applying a braking torque using an electric motor and various brake means.
[0035]
Moreover, it is preferable that the tire ground contact means 20 has a load loading mechanism that applies a force perpendicular to the ground contact surface so that a predetermined load is applied. Examples of this mechanism include a hydraulic device and a device using an elastic restoring force. Moreover, you may provide the measuring device for measuring a load.
[0036]
Further, the tire ground contact means 20 may be provided with a slip angle, a camber angle, or the like. In that case, the tire ground contact means 20 may be provided with a mechanism for tilting the wheel shaft so that a slip angle or a camber angle is generated.
[0037]
Next, the measurement method of the present invention using the tire ground contact surface measuring device as described above will be described. In the measuring method of the present invention, after forming the ice layer 2 on the inner peripheral surface of the cylindrical portion 11 of the rotary drum 10, photographing is performed while irradiating the light by the light irradiating means 5 and rotating the rotary drum 10. The means 6 photographs the tire ground contact surface through the transparent plate 1. However, the measuring device of the present invention can also be used when photographing the tire contact surface in a stationary state without rotating the rotary drum 10.
[0038]
When the rotary drum 10 is rotationally driven to reproduce steady running, the tire 3 grounded by the tire grounding means 20 is preferably rotationally driven at the same speed as the rotary drum 10 or freely rotated. In addition, when reproducing the driving travel time, the grounded tire 3 is driven to rotate faster than the rotary drum 10 and when the braking travel time is reproduced, the braking torque is applied to the grounded tire 3 using an electric motor. You can take it.
[0039]
When the tire contact surface measuring device of the present invention is used, a braking test for examining the relationship between the slip ratio and the contact shape can be performed. In this case, as shown in FIG. 6, the speed of the rotary drum 10 (the inner peripheral surface is the rotational peripheral speed) is kept constant, and the electric motor is controlled to gradually decrease the speed of the tire 3 (peripheral speed). . As a result, the slip ratio can be changed from 0 to 1, for example, and the ground contact shape at an arbitrary slip ratio can be measured.
[0040]
In the present invention, by using the rotary drum 10, the tire contact surface can be measured under conditions close to actual running. For example, it is possible to rotate the inner peripheral surface of the rotary drum 10 at a rotational peripheral speed of 40 km / hr or more and take a picture of the tire ground contact surface in that state. Further, the rotational peripheral speed of the inner peripheral surface can be controlled to a low speed of about 5 km / hr, and the tire contact surface can be photographed at a wide speed.
[0041]
[Other Embodiments]
(1) In the above-described embodiment, an example in which the tire is grounded on the inner surface side of the rotary drum by the tire grounding means has been shown. However, in the present invention, as shown in FIG. A sample grounding means 25 capable of supporting the tire tread sample 26 in a grounded state may be provided on the inner surface of the cylindrical portion 11 of the drum 10.
[0042]
The sample grounding means 25 includes a hydraulic cylinder 25a and a support plate 26a detachably provided at the distal end of the movable part. As the tread sample 26, a tread block unit, a part of the grounding portion, the entire grounding portion, or the like can be used, and these are bonded to the support plate 26a. The support plate 26a may be formed in a curved surface according to the outer surface shape of the tire, or an elastic body may be interposed between the support plate 26a and the tread sample 26 so that the air pressure can be reproduced.
[0043]
When using this apparatus, after forming the ice layer 2 on the inner peripheral surface of the cylindrical portion 11 of the rotary drum 10, while irradiating light by the light irradiation means 5, while rotating or rotating the rotary drum 11, The tread sample 26 can be grounded by the sample grounding means 25, and the tire grounding surface can be photographed by the photographing means 6 through the transparent plate 1.
[0044]
(2) In the above-described embodiment, as shown in FIG. 1A, the example in which the light irradiation means 5 is used to irradiate the ice layer 2 with light substantially parallel thereto is shown. The light irradiation means 5 may irradiate light by a method as shown in FIGS.
[0045]
For example, as shown in FIG. 5A, the light irradiation means 5 is used to irradiate the inside of the transparent plate 1 with light substantially parallel thereto, as shown in FIGS. 5B to 5C, The light irradiating means 5 is disposed on the ice layer 2 side, and the light is reflected by the reflecting mirror 5c disposed in an inclined manner inside the ice layer 2 or the transparent plate 1 so as to irradiate substantially parallel light therein. Also good. The inclination angle of the reflecting mirror 5c is preferably 30 to 60 °, and most preferably around 45 °. The reflecting mirror 5c may be a curved surface type.
[0046]
(3) In the above-described embodiment, an example of a tire ground contact surface measuring device including a rotary drum has been described. However, in the present invention, a disk-shaped or elongated flat plate may be used instead of the rotary drum. In addition, when observing from the pit below the road surface in the course using a real vehicle, the photographing means for photographing the tire ground contact surface from the opposite side of the ice layer through a transparent plate formed on the surface of the ice layer, and its You may provide the transparent plate and / or the light irradiation means which irradiates the light substantially parallel to this inside the ice layer.
[0047]
(4) In the above-described embodiment, an example in which an ice layer is formed on the entire inner surface of the cylindrical portion of the rotary drum has been shown. However, if only a still image is used, only a transparent plate may be used, and a rolling image is taken. It is preferable that an ice layer is formed on the entire inner surface of the drum.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram for explaining the operation of a tire contact surface measuring device (a) according to the present invention in comparison with a conventional device (b). FIG. 2 shows an example of a tire contact surface measuring device according to the present invention. Schematic configuration diagram [FIG. 3] A photograph showing an example of a tire contact surface photographed by the tire contact surface measuring device of the present invention (contact shape photograph near the contact boundary)
FIG. 4 is a schematic configuration diagram showing another example of a tire contact surface measuring apparatus according to the present invention. FIG. 5 is an enlarged view of a main part showing another example of the main part of the tire contact surface measuring apparatus according to the present invention. Conceptual diagram of braking test to investigate the relationship between slip ratio and ground contact shape [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Transparent board 2 Ice layer 3 Tire 3a Tire ground interface 5 Light irradiation means 6 Image | photographing means 7 Position detection means 10 Rotary drum 11 Cylindrical part 20 Tire grounding means 25 Sample grounding means

Claims (6)

Photographing a tire ground contact surface from the opposite side of the ice plate, a transparent plate having an ice layer formed on the surface, light irradiating means for irradiating the transparent plate and / or the inside of the ice layer with light substantially parallel thereto. A tire ground contact surface measuring device comprising photographing means. The tire according to claim 1, further comprising a rotary drum in which the transparent plate forms at least a part of a cylindrical portion and capable of being driven to rotate, and a tire grounding means that can ground the tire in a rotating state on the inner surface side of the cylindrical portion. Ground plane measuring device. 2. The rotary drum in which the transparent plate forms at least a part of a cylindrical portion and can be rotated, and sample grounding means capable of supporting a tread sample of a tire on the inner surface of the cylindrical portion in a grounded state. Tire contact surface measuring device. The transparent plate is provided in a part of the circumferential direction of the cylindrical portion, and the photographing unit photographs a still image according to a sent signal,
4. The tire ground contact surface measuring device according to claim 2, further comprising position detecting means for detecting a rotational position of the rotary drum and sending a signal for determining a photographing timing to the photographing means. Photographing the tire ground contact surface from the opposite side of the ice plate, a transparent plate having an ice layer formed on the surface, light irradiation means for irradiating the transparent plate and / or the inside of the ice layer with light substantially parallel thereto. A photographing drum, a rotary drum in which the transparent plate forms at least a part of a cylindrical portion and which can be driven to rotate, and a tire grounding means capable of grounding the tire in a rotating state on the inner surface side of the cylindrical portion. After forming an ice layer on the inner peripheral surface of the cylindrical portion of the rotary drum using a contact surface measuring device, the photographing is performed while rotating the rotary drum while irradiating light by the light irradiation means. A tire contact surface measurement method for photographing a tire contact surface through a transparent plate by means. The tire contact surface measurement method according to claim 5, wherein the tire contact surface is photographed while applying a braking force or a driving force to the tire.

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