JP4222783B2 - Equipment for measuring the contact shape of tire treads - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for measuring a ground contact shape of a tire tread surface, and more particularly, to a tire contact surface shape measurement apparatus capable of obtaining a ground contact shape close to an actual road surface.
[0002]
[Prior art]
Conventionally, as an apparatus for measuring the ground contact shape of a tire tread, an apparatus that reads a shadow of a ground contact portion of a tire tread running on a road surface for measurement by an image reading unit installed below the road surface for measurement is used. ing. The road surface for measurement is composed of a transparent glass board, and a shadow corresponding to the ground contact shape is formed by blocking the ground contact portion of the tire tread that has traveled the light incident from the side, and the shadow is read by the image reading means. As a result, a grounding shape is obtained.
[0003]
However, in the above-described apparatus, the road surface for measurement is made of a glass board, so that the running surface is smooth, and unlike the road surface state having actual minute irregularities, the ground contact shape of the obtained tire tread is the actual road surface It must be different from the ground contact shape. This is particularly noticeable when braking / driving force is applied or when turning, and is not reliable as data for tire development.
[0004]
[Problems to be solved by the invention]
It is an object of the present invention to provide a tire tread surface contact shape measuring apparatus capable of obtaining a contact shape close to a contact shape on an actual road surface.
[0005]
[Means for Solving the Problems]
According to the tire tread surface contact shape measuring apparatus of the present invention that achieves the above object, the shadow of the contact portion of the tire tread running on the measurement road surface is read by the image reading means from the lower side of the measurement road surface. In the apparatus for measuring a contact shape of a tire tread, the road surface for measurement is made of a translucent material having a light transmittance of 0.2 to 0.8 , and the running surface of the road surface for measurement is an actual road surface. It is characterized by being transferred.
[0007]
According to the present invention configured as described above, the running surface of the road surface for measurement is configured by transferring the actual road surface, so that the ground contact shape of the obtained tire tread is made to be a contact shape very close to the ground contact shape of the actual road surface. be able to. As a result, a ground contact shape close to the actual road surface can be obtained even when the driving force is applied or during turning, and the reliability as data at the time of tire development is significantly improved.
In addition, since it is only necessary to transfer the actual road surface, it is possible to easily perform measurement corresponding to all actual road surfaces.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. In addition, the same component attaches | subjects the same code | symbol and the overlapping description is abbreviate | omitted.
[0009]
FIG. 1 shows an example of a tire tread surface contact shape measuring apparatus according to the present invention, wherein 1 is a measurement road surface on which a measurement tire mounted on a vehicle travels, and 2 is in an underground pit 4 drilled in a test road surface 3. The image reading means installed in
[0010]
The measurement road surface body 1 is constructed on the underground pit 4 with the traveling surface 1a substantially horizontal and is made of a translucent material. The traveling surface 1a has a fine uneven shape on which an actual road surface is transferred. As shown in FIG. 2 (a), the measurement road surface body 1 having such a running surface 1a is shaped by applying a gypsum board 5 to the actual road surface Rs, and the gypsum board 5 is shown in FIG. ), It can be obtained by setting the mold 6 and pouring the translucent material M into the mold 6 and curing it.
[0011]
As the translucent material, any material can be used as long as it can be poured into the mold 6 and cured as described above and can withstand the load of one vehicle traveling on the road surface 1 for measurement. For example, a thermosetting urethane resin and an acrylic resin can be mentioned preferably.
[0012]
The light transmittance of the measurement road surface 1 (ratio X1 / X0 between the light intensity X1 transmitted through the measurement road surface 1 and the light intensity X0 when there is no measurement road surface 1) is 0. The range is from 2 to 0.8. When the transmittance is less than 0.2, it is difficult to clearly determine the shadow of the ground contact portion of the tire tread that travels on the road surface 1 for measurement because it is too dark. On the other hand, if it exceeds 0.8, it becomes difficult to make a shadow, and it becomes difficult to distinguish between the grounded portion and the other portions.
[0013]
Illumination means 7 for illuminating the measurement road surface body 1 is installed around the upper portion of the measurement road surface body 1 as shown in the figure, and the shadow of the tire traveling on the measurement road surface body 1 is clearly defined by the measurement road surface body 1. It is good to be able to form. The illumination means 7 may be a light having a light source as shown in the figure, or a mirror body that reflects sunlight.
[0014]
The image reading means 2 is composed of a high-speed video camera or the like capable of reading an image at a high speed, as in the prior art, and the shadow formed by the ground contact portion of the tire tread running on the road surface 1 for measurement. The included image is captured and the image signal is output to an image analysis means (not shown) installed outside.
[0015]
The image analysis means can discriminate a shadow portion and other portions in each still image state from the input image signal, and can output the shadow portion as a grounding shape of the tire tread and display it on a monitor or the like. I have to.
[0016]
According to the above-described present invention, the running surface 1a of the road surface for measurement 1 is configured by transferring the actual road surface. Therefore, the grounding shape of the obtained tire tread surface is substantially equal to the grounding shape when traveling on the actual road surface. Can be. For this reason, a ground contact shape close to the actual road surface can be obtained even when the driving force is applied or when turning, so that the reliability as data at the time of tire development is greatly improved.
[0017]
In addition, since it is only necessary to transfer the actual road surface, measurement corresponding to all actual road surfaces is possible.
In addition, since the measurement road surface body 1 is made of a translucent material, a light source that makes light incident from the side as in the prior art becomes unnecessary, so that the apparatus cost can be reduced.
[0018]
FIG. 3 shows another example of a tire tread surface contact shape measuring apparatus according to the present invention. This apparatus reduces the thickness of the above-described measuring road surface body 1 and places it on a transparent glass board G. It is a thing. The glass board G supports the load of one vehicle traveling on the road surface 1 for measurement.
[0019]
In such a configuration, the translucent material used for the road surface for measurement 1 does not need to be able to withstand the load of one vehicle traveling on the road surface for measurement 1, and is poured into the mold 6 and cured. Any translucent material that can be used. Even with such an apparatus, the same effects as described above can be obtained.
[0022]
In the present invention, a British portable skid resistance tester (manufactured by STANLEY LONDON Co., Ltd.) is used to check whether or not the running surface 1a of the measurement road surface body 1 to which the actual road surface is transferred is approximated to the actual road surface. If the difference between BPN (Portable Skid Resistance Number) measured by PORTABLE SKID-RESISTANCE TESTER is within 10% compared to the actual BPN measured value on the road, It can be said that the road surface resistance on the traveling surface 1a approximates the actual road surface.
[0023]
Moreover, the difference of the amplitude level A calculated | required from the measured value measured with the road surface property measuring apparatus (For example, Ono Sokki Co., Ltd.) is less than 5 dB with respect to an actual road surface between 20-500 c / m in a distance frequency analysis result. If so, it can be said that the uneven shape on the running surface 1a of the road surface for measurement 1 approximates the actual road surface. The amplitude level A is obtained by A = 10 log (X / 10 ⁻⁶ ) ^2, where X is a measured value (m).
[0024]
In the above-described apparatus, the measurement road surface body 1 is arranged so that the traveling surface 1a thereof is horizontal and the ground contact shape when traveling on a flat ground is measured, but the traveling surface 1a is inclined. It may be arranged so that the ground contact shape on the slope is measured.
[0025]
【The invention's effect】
As described above, the tire tread surface contact shape measuring apparatus according to the present invention is configured by transferring the actual road surface to the running surface of the measurement road surface body, so that a contact shape close to the contact shape on the actual road surface can be easily obtained. it can.
[Brief description of the drawings]
FIG. 1 is a cross-sectional explanatory view showing an example of a tire tread surface contact shape measuring apparatus according to the present invention.
2 (a) and 2 (b) are cross-sectional explanatory views showing steps for producing the measurement road surface body of FIG. 1 respectively.
FIG. 3 is an explanatory cross-sectional view showing another example of a tire tread surface contact shape measuring apparatus according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Road surface for measurement 1a Traveling surface 2 Image reading means 3 Test road surface 4 Underground pit 5 Gypsum board 6 Formwork 7 Illumination means G Glass board Rs Actual road surface

Claims (4)

In the shadow of the ground portion of the tire tread which travels on measuring the road surface body contact shape measuring device of a tire tread which is to read by the image reading means from the bottom side of the measuring road surface body, said measuring road surface of the light An apparatus for measuring a contact shape of a tire tread, which is made of a translucent material having a transmittance of 0.2 to 0.8, and is configured by transferring an actual road surface of a running surface of the road surface for measurement. 2. The tire tread surface contact shape measuring apparatus according to claim 1 , wherein an illuminating means for illuminating the measurement road surface is installed above the measurement road surface. The tire tread surface contact shape measuring apparatus according to claim 1 or 2, wherein the measurement road surface body is placed on a transparent glass board . 4. The tire tread surface contact shape measuring apparatus according to claim 1, wherein the measurement road surface body is a measurement road surface body on which a measurement tire mounted on a vehicle travels.

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