JPH10160437A - Method and device for judging external shape of tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To specify defective concave and convex on the surface of a tire and, at the same time, to recognize the sizes of the concave and convex sections and judge the extents of the defects. SOLUTION: The direction, in which a light emitting section emits light toward a tire is different from the direction in which a light receiving section receives reflected light from the tire by an angle θ. Depending upon the raggedness variation of the surface of the tire, therefore, the height Δh of the tire from a reference plane varies and an offset amount Δd is produced in the radial direction of the tire between reflecting points (an actual reflecting point R on the surface of the tire and a virtual reflecting point V on a reference plane B). As a result, Δh=Δd/tanθholds. Since the offset amount corresponds to the difference of the light receiving position of the light receiving section, the height variation h can be found easily by calculation from the above-mentioned equation when the proper light receiving position of the light receiving section is known.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for determining the outer shape of a tire for determining the state of the outer shape of the tire.

[0002]

2. Description of the Related Art As a defect detection method using a frequency analysis of a surface unevenness waveform of an object to be detected such as a tire, a method based on a fast Fourier transform has been proposed (for example, Japanese Patent Application Laid-Open No. Hei 7-111333; See JP-A-3-54407. For reference, a method based on matching with test data (see Japanese Patent Application Laid-Open No. 3-54407).
Also, a detection method based on a difference between an original waveform (measured waveform) and a delayed waveform (see JP-A-1-51122) has been proposed.

In the method using the fast Fourier transform, it is possible to remove noise (noise) included in measurement data or extract a defective portion (specify a defect position).

[0004]

However, in the method using the fast Fourier transform described above, it is not possible to determine the size of a defective portion. In addition, since the Fourier transform and the inverse transform are performed, a considerable processing time is required. Further, since the processing is repeated several times for the uneven waveform, the signal may be distorted.

In view of the above facts, the present invention provides a method and an apparatus for determining the outer shape of a tire which can identify the irregularities on the surface of the tire, recognize the size of the irregularities on the tire, and judge the degree of the defect. The purpose is to get.

[0006]

According to the first aspect of the present invention, a measuring point is defined on a side surface of a tire, and the measuring point is fixed over the entire circumference of the tire toward the measuring point while maintaining a radius of the measuring point. By irradiating a light beam of an amount of light and receiving the reflected light of the light beam at a position at a predetermined angle θ with respect to the irradiation direction of the light beam, the tire side surface is determined based on the amount of received light displacement at each measurement point. Determining the degree of defect based on the position, size, and shape of the extracted defect asperity, based on the amount of surface asperity variation, extracting the defect asperity based on the amount of surface deviation. And

According to the first aspect of the present invention, a light beam is radiated toward a measurement point defined on the side of the tire, and a reflected light reflected from the radiated position is received to determine a light-receiving variation. By performing this operation for the entire circumference of the tire, the received light displacement amount data at a plurality of measurement points on a concentric circle on the tire side surface is prepared.

[0008] The amount of change in the received light has a correlation with the amount of change in the surface unevenness of the tire side surface. By utilizing this correlation, the amount of the unevenness of the surface of the tire side is obtained based on the amount of change in the received light.

[0009] The surface irregularities include intentional irregularities such as tire logo marks. Therefore, by changing the radius dimension of the measurement point, the reflected light is similarly received at a plurality of measurement points on different concentric circles, and the plurality of measurement points on the plurality of concentric circles along the tire radial direction are received. The surface irregularity shift amount is obtained from the amount data.

By comprehensively judging these, it is possible to determine whether the surface unevenness is intentional or a defect unevenness portion. Only the defect unevenness portion is extracted, and the extracted defect unevenness portion is extracted. The degree of defect is determined based on the position, size, and shape of.

The invention according to claim 2 is characterized in that, when the light beam is reflected at a relatively low position on the side surface of the tire, the light reception amount is small, and when the light beam is reflected at a high position, the light reception amount is large. I have.

According to the second aspect of the present invention, the light beam is received at a predetermined angle θ as a correlation with the amount of change in the surface unevenness of the tire side surface. Taking advantage of the fact that the amount of change in received light is small when reflected at a position and the amount of change in received light is large when reflected at a high position, the amount of change in the surface unevenness of the tire can be determined.

According to a third aspect of the present invention, at least a fixing means for fixing the tire, a rotation driving means for rotating the tire fixed to the fixing means, and the same rotation of the tire by the rotation driving means, the rotation of the tire at the same time. A light emitting means for irradiating a light beam of a constant light amount to a measurement point on the core circle; and a light emitting unit disposed corresponding to the light source unit and reflecting from the tire at a position at a predetermined angle θ with respect to the irradiation direction of the light beam. Light-receiving means for receiving light; light-receiving displacement-concavo-convex displacement converting means for converting a plurality of light-receiving displacements on a concentric circle received by the light-receiving means into surface irregularity displacements on the tire side surfaces; and the light-receiving displacement Based on the amount of change in the surface irregularities of the tire obtained by the unevenness change amount conversion means, based on the extraction means for extracting the unevenness of the defect, and the position, size, and shape of the unevenness of the defect extracted by the extraction means; , Said Thailand It has a determining means for determining defective degree, the.

According to the third aspect of the present invention, in a state where the tire is fixed by the fixing means and the tire is rotated (preferably at a constant speed) by the rotation driving means, the light emitting means is directed toward the measuring point. To irradiate a light beam. The light receiving means receives the reflected light of the light beam reflected from the tire.

Next, a plurality of light-receiving variations on the concentric circles received by the light-receiving means are converted into surface unevenness variations on the side surface of the tire by the light-receiving variation-concave / convex variation conversion means.

The extracting means extracts a defect unevenness portion based on the converted surface unevenness change amount, and the judging means judges the degree of tire defect from the extracted defect.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the light emitting means simultaneously irradiates a plurality of measurement points having a common radial direction and different radial dimensions, The light receiving means receives reflected light from a plurality of measurement points having a common radial direction at the same time.

The amount of surface irregularity displacement includes intentional irregularities such as tire logo marks. Therefore, by changing the radius dimension of the measurement point, the reflected light is similarly received at a plurality of measurement points on different concentric circles, and the plurality of measurement points on the plurality of concentric circles along the tire radial direction are received. The surface irregularity displacement amount is obtained from the displacement amount data.

By comprehensively judging these, it is possible to determine whether the surface irregularities are intentional or defect irregularities. Only these defect irregularities are extracted, and the extracted defect irregularities are extracted. The degree of defect is determined based on the position, size, and shape of.

According to a fifth aspect of the present invention, in the fourth aspect of the invention, the light emitting means is a linear light source extending in a tire radial direction, and the light receiving means is at least along the linear light source. And a line sensor or an area sensor in which light receiving elements are arranged.

Since each measurement point is a group of different points, if this is used as a linear light source, finer data can be obtained depending on the resolution of the light receiving element of the line sensor or the area sensor as the light receiving means. Can be.

[0022]

FIG. 1 shows a tire shape inspection apparatus 100 (hereinafter, simply referred to as an inspection apparatus 100) according to the present embodiment.

The inspection apparatus 100 has a holder 104 as a fixing means for holding the tire 102. The holder portion 104 has a role as a wheel on which the tire 102 is mounted. After the tire 102 is mounted, air can be injected.

The holder section 104 has a pair of disk sections 106 arranged facing each other and parallel to each other. Rotation shafts 108 and 110 are coaxially mounted at the centers of the pair.

The rotating shaft 108 is connected to a rotating shaft (not shown) of the motor 112 via a gear (not shown) or a belt so that the driving force of the motor 112 is transmitted. The motor 112 is a personal computer 114
(Hereinafter, referred to as a personal computer 114), the holder unit 1 is rotated in response to an instruction signal from a drive control unit 116 connected thereto.
04 can be rotated at a constant speed.

Tire 102 mounted on holder 104
The light emitting unit 1 faces the side surface (the upper surface in FIG. 1)
18A and the light receiving section 118B are provided as a pair. The light emitting unit 118A is provided with the support arm 12
The light receiving portion 118B is attached to a position just above the side surface of the tire.

A plurality of light beams (see a dashed line in FIG. 1) arranged in the radial direction of the tire 102 are parallel to each other from the light emitting portion 118A and are perpendicular to the tire reference plane B as shown in FIG. Irradiation is performed on the tire side surface so as to have a predetermined angle θ with respect to L. The tire reference plane B is virtually provided, and may be any plane as long as the predetermined angle θ coincides. In the present embodiment, the tire reference plane B is set inside the tire surface, and is set to a position where the light receiving position shift amount can be relatively large within the light receiving range of the light receiving unit 118B described later. .

The light receiving section 118B, which is disposed at a position directly above the tire surface, employs a CCD line sensor. The light receiving section 118B is formed in a band-like area along the plurality of light beam lines arranged in a straight line. The reflected light (see the chain line in FIG. 1) from the corresponding tire 102 is received.

The light receiving data of the light receiving section 18B is stored in the storage device 1
30 is stored. The storage device 130 is connected to a personal computer 114 as an image processing device.

In the personal computer 114, the following processing is executed. As shown in FIG. 3, there is a difference in angle θ between the irradiation direction of the light beam from the light emitting unit 118A and the light receiving direction of the reflected light from the tire by the light receiving unit 118B. Therefore,
According to the amount of unevenness of the surface of the tire 102, the reference plane B
Are different from each other, and an offset amount Δd in the tire radial direction of the reflection point (the reflection point R on the tire surface that actually reflects and the virtual reflection point V on the reference plane B) occurs. Therefore, the following (1) holds.

Δh = Δd / tan θ (1) Since the offset amount corresponds to the difference between the light receiving positions in the light receiving section 118B, if the position where light is to be received is known, the above equation (1) is used. By using, the amount of height change Δ
h can be easily calculated.

On the monitor 132 of the personal computer 114, the surface shape of the side surface of the tire 102 is three-dimensionally displayed on the basis of Δh obtained by the above equation (1), or a desired shape as shown in FIG. The section shape is displayed. As the data display, as shown in FIG.
It is possible to display a characteristic diagram of the light-receiving variation Δd for one round of No. 02 and a characteristic diagram of the radial unevenness variation Δh of the tire 102 as shown in FIG. From these display data, the position of the unevenness shift amount can be recognized.

In the personal computer 114, the tire 102
In addition to obtaining the amount of unevenness of the surface, it is also possible to extract a defect uneven portion from the amount of unevenness. As a first method, a defect uneven portion can be extracted by multiplying a plurality of data in different radial directions.

That is, as shown in FIG.
The uneven portion of 02 can be classified into an intentional uneven portion 102A such as a tire logo mark and a defective uneven portion, and the position of the intentional uneven portion 102A such as a tire logo mark can be recognized to some extent. . Further, the defect unevenness has a property of being continuous in the radial direction. From these, at least two types of measurement points (measurement circles) having different radial dimensions such that the intentional uneven portion 102A such as a tire logo mark is not detected at the same time are selected, and these are multiplied to obtain an intended intention. The typical uneven portion is erased, and the defective uneven portion is amplified.

As a second technique, the intentional irregularities 10
The difference in shape between 2A and the concave and convex portions is used. That is,
The intentional irregularities 102A are so-called rectangular irregularities that rise sharply (almost at right angles) and fall sharply (almost at right angles), while the defect irregularities rise with a relatively gentle slope, and This is a so-called mountain-shaped unevenness that falls with a gentle inclination. Therefore, 1
Focusing on the amount of change with reference to one measurement point (measurement circle), and when there is a sharp rise, repeating the transition to another measurement point (measurement circle), It is possible to recognize the position, the size, and the shape of the defective uneven portion for one circumference of the tire while avoiding 102A.

The operation of this embodiment will be described below. The tire 102 to be inspected is mounted on the holder 104,
Inject air. In this state, the motor 112 is driven to rotate the holder 104.

In this state, a plurality of mutually parallel light beams are emitted from the light emitting section 118A toward the side surface of the tire 102. The position of the angle θ with respect to this irradiation direction (the tire 10
A light receiving portion 118B is provided immediately above the second side surface), and the light receiving portion 118B receives reflected light of the light beam from the tire 102. This received light data
The data is stored in the storage device 130 and sent to the personal computer 114 when all the data are collected, and the following image processing is executed.

At this time, when the light beam is reflected by a virtually provided reference plane having the same optical path length, the light receiving unit 11
The light receiving position by 8B is known in advance.

However, since the surface of the tire 102 is at a position higher than the reference plane and is a curved surface, it is shifted from the known light receiving position. In addition, if there is an uneven portion on the surface of the tire 102, the light receiving position is further shifted.

As shown in FIG. 3, the amount of displacement Δd of the light receiving position is different from the amount of displacement Δh from the reference plane.
There is a correlation as shown in equation (1).

Δh = Δd / tan θ (1) Accordingly, in the personal computer 114, if the amount of shift Δd of the light receiving position by the light receiving section 118B is known, the shift data as shown in FIG. Can be. In this case, the larger the amount of displacement Δd is, the more convex it is.

Further, as shown in FIG. 6, by calculating Δh based on the equation (1), the transition of the height change for one rotation of the tire 102 can be displayed on the monitor 132.

Further, the personal computer 114 can display the surface of the tire 102 three-dimensionally or a sectional view of a desired position as shown in FIG. 4 based on the above data.

The operator may extract the irregularities of the tire 102 from such display contents, but it is also possible to automatically extract the irregularities of the tire 102.

That is, a plurality of data in different radial directions are multiplied (first method). In the uneven portion of the tire 102, intentional uneven portion 102 such as a tire logo mark is provided.
A and a defect uneven portion, and the position of the tire logo can be recognized to some extent. Further, the defect unevenness has a property of being continuous in the radial direction. From these facts, at least two types of measurement points (measurement circles) having different radial dimensions such that the intentional uneven portion 102A such as a tire logo mark is not detected at the same time are selected, and these are multiplied to obtain an intended intention. The typical uneven portion is erased, and the defective uneven portion is amplified. Only the defective uneven portion can be extracted by comparing a predetermined threshold value.

As a second technique, a difference in shape between intentional uneven portions and defective uneven portions is used. That is, the intentional irregularities are so-called rectangular irregularities, while the defect irregularities are so-called mountain-like irregularities. Therefore, the tire 1 is determined based on one measurement point (measurement circle) of the obtained unevenness shift amount data.
The irregularities for one round of 02 are detected, and when there is a sharp rise, the transition to another measurement point (measurement circle) is repeated. As a result, it is possible to recognize the position, size, and shape of the defective uneven portion for one round of the tire while avoiding intentional unevenness.

According to the present embodiment, by irradiating a light beam and receiving the reflected light of this light beam from the tire 102 at a predetermined angle θ, the unevenness of the surface of the tiger 102 is obtained from the displacement of the light receiving position. Since the shape can be ascertained, it is possible to quickly and reliably extract the irregularities on the surface of the tire 102 without performing complicated processing such as Fourier transform.

In the present embodiment, the light emitting section 118A
Although a plurality of light beams are irradiated from the above, a continuous linear light (slit light) along the radial direction of the tire 102 may be irradiated. In this case, the light receiving unit 1
The measurement points (measurement circles) of the tire 102 can be increased depending on the resolution on the 18A side.

Although a line sensor is used as the light receiving section 118B, an area sensor may be used.

[0050]

As described above, the method and apparatus for judging the outer shape of a tire according to the present invention specify defect irregularities on the tire surface, recognize the size of the defect irregularities, and judge the degree of defect. It has an excellent effect that it can be produced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a tire shape inspection device according to the present embodiment.

FIG. 2 is a perspective view of a tire to be inspected.

FIG. 3 is an explanatory diagram for recognizing a tire surface shape by receiving reflected light of a light beam.

FIG. 4 is a characteristic diagram displayed on a monitor, which is a cross-sectional shape of a tire surface.

FIG. 5 is a characteristic diagram displayed on a monitor, and is a characteristic diagram of a light receiving position shift characteristic for one rotation of a tire.

FIG. 6 is a characteristic diagram displayed on a monitor, and is a height change characteristic diagram of a part of a tire.

[Explanation of symbols]

REFERENCE SIGNS LIST 100 tire shape inspection apparatus 102 tire 104 holder part (fixing means) 108A light emitting part (light emitting means) 108B light receiving part (light receiving means) 112 motor (rotation driving means) 114 personal computer (light receiving displacement-concave and convex displacement conversion means, extraction means , Determination means)

Claims (5)

[Claims] 1. A measuring point is defined on a side surface of a tire, and a constant amount of light beam is radiated toward the measuring point over the entire circumference of the tire while maintaining a radius of the measuring point. By receiving the reflected light of the light beam at a position at a predetermined angle θ with respect to the direction, the amount of displacement of the surface unevenness of the tire side surface is determined based on the amount of displacement of the light receiving position at each measurement point. A method for determining the outer shape of a tire, comprising: extracting a defect uneven portion based on an amount; and determining a defect degree based on a position, a size, and a shape of the extracted defect uneven portion. 2. The tire according to claim 1, wherein the light receiving amount is small when the light beam is reflected at a relatively low position on the tire side surface, and the light receiving amount is large when the light beam is reflected at a high position. Outer shape determination method. 3. A fixing means for fixing at least the tire, a rotation driving means for rotating the tire fixed to the fixing means, and a measurement point which is on a concentric circle on the side surface of the tire when the rotation driving means rotates the tire. A light-emitting means for irradiating a light beam of a constant amount to the light-receiving means, and a light-receiving means arranged to correspond to the light source unit and receiving reflected light from the tire at a position at a predetermined angle θ with respect to the irradiation direction of the light beam. A light-receiving displacement-concavity-conversion displacement converting means for converting displacements of a plurality of light-receiving positions on a concentric circle received by the light-receiving means into a surface irregularity displacement on a tire side surface; Extraction means for extracting a concave and convex portion based on the amount of change in the surface irregularities of the tire obtained by the means, The position and size of the concave and convex portion extracted by the extracting means,
Determining means for determining the degree of defect of the tire based on the shape; 4. The light emitting means simultaneously irradiates a plurality of measurement points having a common radial direction and different radial dimensions, and the light receiving means reflects light from a plurality of measurement points having a common radial direction. The tire outer shape judging device according to claim 3, wherein light is received at the same time. 5. The light-emitting unit is a linear light source extending in a tire radial direction, and the light-receiving unit is a line sensor or an area sensor in which light-receiving elements are arranged at least along the linear light source. The tire outer shape determining device according to claim 4, wherein