JP6959849B2 - Ground plane observation method - Google Patents

Description

The present invention relates to a method for observing a contact patch of a rubber elastic body such as a tire.

The sipes (grooves) formed in the tread of the tire have functions such as adjusting the hardness of the tread, increasing the contact area with the road surface, and increasing the frictional force. In order to investigate the function of such a sipe, it is desirable to directly observe the ground contact surface of a running tire, but in reality it is difficult, so various methods for visualizing the ground contact state have been tried.

One of them is to place a tire on a transparent body, move the tire while pressing it, and irradiate light from the side opposite to the tire contact surface of the transparent body for observation. The transparent material used had a smooth surface in contact with the tire.

For example, in Patent Document 1, in order to facilitate the distinction between the grounded portion and the non-grounded portion in the observation method using such a transparent body, the light is totally reflected on the surface of the transparent body and the light is confined inside the transparent body. It is proposed to arrange the light source so as to. In this case as well, it is necessary to smooth the surface of the transparent body in order to totally reflect the light.

However, when the smooth surface is a ground plane, the behavior of the sipe does not reflect the behavior on an uneven actual road, so it was not possible to accurately know the function of the sipe. That is, tires running on an actual road close or open the sipe due to the unevenness of the road surface. Therefore, by examining the open / closed state of such a sipe, for example, a sipe that contributes to drainage can be identified, but a smooth surface. This is because such opening and closing does not occur and all sipes remain open with almost the original groove width.

Japanese Unexamined Patent Publication No. 3-146809

The present invention has been made in view of the above, and an object of the present invention is to provide a contact patch observation method that enables observation of a tire contact patch under conditions closer to an uneven actual road.

The ground contact surface observation method of the present invention is a ground contact surface observation method for observing a ground contact surface in contact with a rubber elastic body having a sipe, and in order to solve the above problems, a phosphor in the sipe of the rubber elastic body. The surface of the rubber elastic body holding the phosphor is brought into contact with the road surface of the light transmissive body having one surface formed as a road surface, and light is transmitted to the ground surface of the rubber elastic body. The method is to irradiate light from the body side and acquire an image showing the light emitting state of the ground contact surface of the rubber elastic body. Here, "light" refers not only to visible light but also to all energy rays (electromagnetic waves) that can induce fluorescence from a fluorescent substance contained in a phosphor, and includes X-rays and ultraviolet rays.

In the above-mentioned contact patch observation method, the road surface may be a surface having irregularities (hereinafter, referred to as "concave surface").

Further, the phosphor can be supported on a carrier and inserted into the sipe.

It is also possible to acquire a plurality of images while moving the rubber elastic body on the road surface.

The above contact patch observation method can be applied to both wet and dry road surfaces.

According to the contact patch observation method of the present invention, it is possible to observe the state of the tire contact patch during traveling under conditions closer to the uneven actual road. Therefore, for example, a sipe that contributes to drainage on a wet road surface can be easily identified.

It is explanatory drawing which shows the structure of the ground plane observation apparatus A which can be used in the ground plane observation method which concerns on one Embodiment of this invention. It is a schematic enlarged cross-sectional view which shows the rubber elastic body 1 on the light transmission body 2 of the ground plane observation apparatus A.

Hereinafter, embodiments for carrying out the present invention will be described in detail, but the present invention is not limited to the following embodiments.

As one embodiment, the ground plane observation method of the present invention can be performed using the device A having the configuration shown in FIG. In FIG. 1, reference numeral 1 is a rubber elastic body such as a tire or a cut piece thereof to be observed, reference numeral 2 is a light transmitting body, reference numeral 3 is a light source, reference numeral 4 is a dichroic mirror, reference numeral 5 is a detection unit, and reference numeral 6 is light. The road surface, which is the upper surface of the permeator 2, and the reference numeral 7 indicate water. As shown in FIG. 2, the rubber elastic body 1 has three sipes 8, 9, and 10, and although not shown, each sipe has a zigzag shape on the ground plane, and the three sipes are parallel to each other. It is formed to be. The rubber elastic body 1 is placed on the light transmitting body 2 so that the openings of these sipes 8, 9 and 10 are in contact with the road surface 6, and the phosphor 11 is inserted in each sipe in advance. The phosphor 11 is not exposed from the opening of each sipe and is inserted at a position where light does not reach when the sipe is closed. The road surface 6 is an uneven surface, and is a wet road surface on which water 7 is spread.

The arrows in FIG. 1 indicate the path of light from the light source 3 to the detection unit 5. That is, the light emitted from the light source 3 reaches the dichroic mirror 4, and only the light having a specific wavelength is reflected by the dichroic mirror 4 and transmitted through the inside of the light transmitting body 2, and the rubber elastic body 1 Reach the surface of. When the sipes 8, 9 and 10 formed on the ground plane of the rubber elastic body 1 are open, light reaches the phosphor 11 inserted therein and fluorescence is induced, and this fluorescence transmits light. It passes through the body 2 and the dichroic mirror 4 and reaches the detection unit 5. The detection unit 5 receives this fluorescence, converts it into an electric signal, and images it. Therefore, the shape of the phosphor 11 contained inside the sipes 8, 9, and 10 on the ground plane of the rubber elastic body 1 is visualized, and this can be regarded as the shape of the open sipes. As described above, according to the present embodiment, the opening and closing of the sipe can be visualized by using the induced fluorescence method, and therefore, for example, the sipe that contributes to drainage on the actual road can be specified. The phosphor will be described later.

In FIG. 1, the optical axis of light from the light source 3 to the rubber elastic body 1 and the optical axis of fluorescence emitted from the phosphor in the sipe of the rubber elastic body 1 are shown as parallel lines by shifting for convenience. However, in reality, these optical axes overlap.

The material of the light transmitter 2 is not limited, but is, for example, glass or synthetic resin. A transparent body is preferably used as the light transmitting body 2, but it does not necessarily have to be transparent, and the light from the light source 3 side and the fluorescence from the rubber elastic body 1 side are transmitted, which is the object of the present invention. It suffices if there is enough light transmission to enable visualization of the ground plane. By making the road surface 6 of the light transmitter 2 an uneven surface corresponding to the actual road, it is possible to observe under conditions closer to the observation on the actual road, and the roughness of the unevenness can be appropriately adjusted according to the purpose of observation.

The light source 3 is not particularly limited as long as it irradiates an energy ray capable of inducing fluorescence from the phosphor used, and for example, a xenon lamp, a mercury lamp, a halogen lamp, or an LED light can be used.

As described above, the dichroic mirror 4 is a mirror that reflects only light of a specific wavelength among the light from the light source 3, and is suitable for the purpose of observation depending on the type of phosphor and the light source 3 to be used. May be selected as appropriate. Not all the light that reaches the surface of the light transmission 2 is absorbed, but a part of it is usually reflected, and if this reflected light enters the detection unit 5, fluorescence may not be detected, but the dichroic mirror 4 has. It also has the effect of cutting such reflected light and enabling more accurate fluorescence detection.

The method of irradiating the ground plane with light is not limited to the above, and for example, a laser beam that emits only one wavelength of light can be used as the light source 3. However, as described above, epi-illumination is adopted in which the light of a specific wavelength emitted from the light source 3 and reflected by the dichroic mirror 4 which is a half mirror reaches the ground plane of the rubber elastic body 1 to be observed. When coaxial illumination is adopted in which the optical axis of light reaching the ground plane and the optical axis of fluorescence emitted from the surface of the rubber elastic body 1 and reaching the detection unit 5 are aligned, the device can be miniaturized and is more convenient. Observation is possible.

The detection unit 5 is a portion that receives fluorescence emitted from a fluorescent substance contained in the phosphor and images the distribution state of the fluorescent substance on the ground plane of the rubber elastic body 1, for example, an electrified coupling element (Charge-coupled). A CCD image sensor using device, CCD) can be used. In that case, the distribution state of the fluorescent substance is obtained as an image by converting the photon energy of fluorescence into electron energy by the CCD, signaling it, and converting it into a desired image format.

For example, if the fluorescent substance stays in the sipe and does not leak to the ground plane, the fluorescent substance in the closed sipe is not detected, so the image of the distribution state of the fluorescent substance can be regarded as the shape of the open sipe. can.

On the other hand, if the fluorescent substance leaks from the sipe to the ground plane, check the difference in brightness due to the shade of the fluorescent substance, image only the part where the brightness is above a certain value, and consider it as the shape of an open sipe. You can also. In the case of a wet road surface as shown in FIGS. 1 and 2, the fluorescent substance is easily eluted from the sipe by the water on the road surface, but even in such a case, the shape of the sipe can be specified by such a method.

In the observation method of the above embodiment, the rubber elastic body 1 is brought into contact with the road surface 6 while being pressed by a pressing means (not shown), if necessary. In order to know the state of the contact patch of the tire while traveling on the actual road, it is preferable to separately measure the pressure applied to the contact patch of the tire and observe the rubber elastic body 1 while maintaining the pressed state at that pressure. ..

Further, if necessary, a plurality of images can be acquired while the rubber elastic body 1 is moved on the road surface 6 by a moving means (not shown). In that case, by comparing these images with each other, it becomes possible to know the state of the sipe more accurately, and for example, a more detailed knowledge about the behavior of the sipe of the running tire can be obtained. For the movement, for example, as shown by the arrow X in FIG. 2, the rubber elastic body 1 may be slid in the horizontal direction on the road surface 6.

The term "fluorescent substance" as used herein refers to an electron that is excited by being irradiated with energy rays such as X-rays, ultraviolet rays, and visible rays and absorbing the energy, and when it returns to the basal state, it transfers energy. The term "fluorescent substance" refers to all substances emitted as electromagnetic waves, and the term "fluorescent substance" refers to these fluorescent substances themselves, or a solid such as a liquid such as an aqueous solution containing these fluorescent substances or a powder.

The fluorescent substance is not particularly limited, but commercially available substances such as paints can be used, and specific examples thereof include pyranine, New Coccine, Rhodamine B, and Eosin. Y), Uranine, PhloxineB and the like can be mentioned. For example, pyranine is preferably used from the viewpoint of the amount of light observed and the ease of handling.

The form of the phosphor may be liquid or solid as described above, and is not particularly limited. However, from the viewpoint of ease of use, a solution obtained by dissolving a water-soluble fluorescent substance in a solvent such as water (hereinafter, "" Fluorescent solution) is preferable. The concentration and amount of the fluorescent liquid are appropriately adjusted according to the type of fluorescent substance used, the purpose of observation including the state of sipe, and the like.

From the viewpoint that a sufficient amount of fluorescent substance can be more reliably retained in the sipe, it is preferable that a carrier having high water absorption is impregnated with a fluorescent solution which is an aqueous solution, and this is inserted and retained in the sipe. It can be used for observation in the state where it is allowed to move. The material of the carrier is not limited, but for example, textile products such as woven cloth and non-woven fabric, paper, resin foam (sponge), and the like can be used. The shape of the carrier is not particularly limited, but the efficiency of the work of inserting into the sipe can be improved by forming an elongated sheet or string according to the length of the sipe.

However, depending on the purpose of observing the ground surface, the fluorescent solution may be injected as it is into the sipe of the rubber elastic body, or the solid fluorescent substance may be filled as it is for observation without using the above-mentioned carrier. It is also possible.

Further, for example, in the case of a water-soluble fluorescent substance that exhibits fluorescence when dissolved in water, the case is not limited to the case where it is held in the sipe in the state of the aqueous solution, and the inside of the sipe is in a solid state due to drying or the like. May be held in. For example, there is a case where the carrier impregnated with the aqueous solution is held in the sipe in a dry state. Alternatively, there are cases where the water-soluble fluorescent substance is filled in the sipe as a solid, or the water-soluble fluorescent substance is supported on the carrier as a solid. Even in such a case, if the road surface is a wet road surface, the water-soluble fluorescent substance can be dissolved by the water to exhibit fluorescence. Therefore, by detecting the fluorescence, an open sipe can be detected. Can be identified.

Although the observation on a wet road surface has been mainly described above as an example, the ground plane observation method of the present invention can be applied to a dry road surface as a matter of course.

The contact patch observation method of the present invention can be used for observing the tire contact patch used in various vehicles such as passenger cars, light trucks, and buses.

A ... Ground plane observation device 1 ... Rubber elastic body 2 ... Light transmitter 3 ... Light source 4 ... Dichroic mirror 5 ... Detection unit 6 ... Road surface 7 ... Water 8, 9, 10 ... Sipe 11 ...... Phosphorus

Claims (6)

This is a contact patch observation method for observing a contact patch in which a rubber elastic body having a sipe is in contact with the road surface.
Hold the phosphor in the sipe of the rubber elastic body,
A surface having a sipe of a rubber elastic body holding the phosphor is brought into contact with the road surface of a light transmitting body having one surface formed as a road surface.
The ground plane of the rubber elastic body is irradiated with light from the light transmitting body side.
A method for observing a ground plane, which acquires an image showing a light emitting state of the ground plane of the rubber elastic body. The contact patch observation method according to claim 1, wherein the road surface is a surface having irregularities. The contact patch observation method according to claim 1 or 2, wherein the phosphor is supported on a carrier and inserted into a sipe. The ground plane observation method according to any one of claims 1 to 3, wherein a plurality of images are acquired while the rubber elastic body is moved on the road surface. The ground plane observation method according to any one of claims 1 to 4, wherein the road surface is a wet road surface. The ground plane observation method according to any one of claims 1 to 4, wherein the road surface is a dry road surface.

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