JP2009115715A - Apparatus for measuring length of tread rubber of tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure the length of the tread rubber of a tire, with accuracy. <P>SOLUTION: A measuring apparatus is equipped with a first photographing means for photographing a front end surface of the tread rubber over the entire length in the width direction; a second photographing means for photographing a rear end surface of the tread rubber, over the entire length in the width direction, which is positioned so as to be separated by a dimension corresponding to the length of the tread rubber; a sensing means which transmits a trigger signal, in synchronization with the first and second photographing means, when sensing a passage of the front end surface; first and second illuminating means for illuminating the front and rear end surfaces with light and enabling respective tilt surfaces and upper edges of the front and second end surfaces to be identified; an arithmetic processing means for capturing front and rear end surface images and deriving the length of the tread rubber, by adding the distances between the reference line of the first photographing means and the edge of the front end surface image and between the reference line of the second photographing means and the edge of the rear end surface image, to the distance between the reference lines; and a display means for displaying the length of the tread rubber. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a tire tread rubber length measuring device, and more particularly, to accurately measure the length of a tire tread rubber that is cut with both front and rear end surfaces being inclined.

The tire tread rubber is a long sheet-like rubber that is cut to a predetermined length according to the outer diameter of a molding drum to be attached, and whose front end surface and rear end surface are inclined surfaces. Accurate measurement is also important for improving tire uniformity.
For example, in Japanese Patent Application Laid-Open No. 6-323817 (Patent Document 1), as shown in FIGS. 7A to 7C, the slit light S is projected from the projector 6 so as to intersect the lower edge 2 of the tire tread rubber 1. The image of the lower surface 3 and the inclined surface 4 sandwiching the lower end edge 2 photographed by projection is taken into the image processing device 5, and the inclination inflection point Sa of the slit light S is determined as the lower end edge 2 and the inclination inflection point. The distance a between Sa and the reference position of the shutter camera 7 is calculated, and the length L of the tire tread rubber 1 is obtained from the formula: L = a + b + c (b: the shutter camera 7 is detected from the rear end detector inputted in advance. Distance to the reference position, c: offset distance).

  However, the front and rear end surfaces of the tire tread rubber tend to be curved surfaces rather than completely inclined planes. Therefore, as in Patent Document 1, when the tilted inflection point Sa of the slit light S is detected at the pinpoint as the lower end edge 2, the lower end edge 2 detected as the tilted inflection point Sa depending on the position where the slit light S is irradiated. The distance a between the shutter camera 7 and the reference position of the shutter camera 7 fluctuates, and the value of the length L of the tire tread rubber 1 obtained as a result varies, which makes it difficult to measure the tread rubber length with high accuracy.

JP-A-6-323817

  This invention is made | formed in view of the said problem, and makes it the subject to measure the length of tire tread rubber with high precision.

In order to solve the above-described problems, the present invention provides a tire-tread rubber having a long sheet shape, which is cut to a required length and the cut front end surface and rear end surface are inclined surfaces, and is horizontally placed on a conveyor. A device for measuring the length of the tire tread rubber in the process of transporting
A first photographing means for photographing the front end face over the entire length in the width direction, fixed above the conveyor, and a dimension corresponding to the length of the tire tread rubber upstream from the first photographing means in the conveying direction; A second imaging means for positioning the rear end face over the entire length in the width direction;
When the passage of the front end surface, which is the front end side in the conveyance direction of the tire tread rubber, is detected between the first imaging unit and the second imaging unit and in the vicinity of the first imaging unit, the first, Detection means for transmitting a shutter start synchronization trigger signal to the second photographing means;
When photographing from above with the first and second photographing means, the front end surface and the rear end surface of the tire tread rubber are irradiated with light, and the inclined surfaces and the upper end edges of the front end surface and the rear end surface are made to have an overall length in the width direction. A first illumination means and a second illumination means for clearly distinguishing over
The front end image and the rear end image of the tire tread rubber photographed by the first and second photographing means are captured, and the distance (L1) between the reference line of the installation position of the first photographing means and the upper edge of the front end image And the distance (L2) between the reference line of the installation position of the second photographing means and the upper edge of the rear end image in addition to the distance between the reference lines of the first and second photographing means, and the tire tread rubber Arithmetic processing means for obtaining the length of the tire, and display means for displaying the length of the tire tread rubber obtained by the arithmetic processing means,
An apparatus for measuring the length of a tire tread rubber is provided.

According to the above configuration, the front end surface and the rear end surface of the tire tread rubber in the conveyance process can be simultaneously photographed by the first photographing unit and the second photographing unit capable of photographing over the entire length in the width direction. From the rear end image, the distance (L1) between the reference line of the first photographing means and the upper end edge of the front end image and the distance (L2) between the reference line of the second photographing means and the upper end edge of the rear end image are calculated. The length of the tire tread rubber can be easily obtained by simply adding the distances (L1, L2) to the distance between the reference lines of the first and second photographing means.
In particular, in the present invention, since the first and second illumination means clearly distinguish each slope and upper end edge of the front end face and the rear end face over the entire length in the width direction at the time of shooting, In the image and the rear end image, the upper end edge can be detected as an edge line extending over the entire length in the width direction. Therefore, compared with the conventional measurement in which the edge is detected at the pinpoint, the reference point of the first photographing means setting position and the front end image are obtained, for example, by taking an average distance by the detection point of the upper edge greatly increasing. The distance (L1) to the upper edge of the image and the distance (L2) between the reference line of the second imaging means setting position and the upper edge of the rear end image can be calculated with high accuracy, and therefore the length of the tire tread rubber can also be calculated with high accuracy. It can be calculated.

The “upper edge” in the present invention refers to an edge that forms a boundary between the upper surface of the tire tread rubber placed on the conveyor and the cut inclined surface among the edges of the tire tread rubber front end surface and rear end surface. Means.
Further, the distance (L1) between the reference line of the first photographing means and the upper end edge of the front end image and the distance (L2) between the reference line of the second photographing means and the upper end edge of the rear end image are set as the first and first. The calculation of the length of the tire tread rubber in addition to the distance between the reference lines of the two photographing means is specifically that the upper end edge of the front end image and the upper end edge of the rear end image are not located between the reference lines. When the L1 and L2 are positive values, and the upper edge of the front end image and the upper end edge of the rear end image are located between the reference lines, L1 and L2 are expressed as negative values. This means that the length L can be calculated by the formula: L = L3 + L1 + L2 (L3: distance between reference lines). Therefore, L1 and L2 when the upper end edge of the front end image and the upper end edge of the rear end image are not located between the reference lines are negative values, and the upper end edge of the front end image and the upper end edge of the rear end image are between the reference lines. In the case where L1 and L2 are expressed as positive values, it means that the tire tread length L can be calculated by the formula: L = L3-L1-L2.

Specifically, as described above, the second photographing means is positioned away from the first photographing means fixed above the conveyor at a distance upstream of the conveyance direction and corresponding to the length of the tire tread rubber. For this reason, when the front end surface of the tire tread rubber in the conveyance process enters the field of view of the first photographing means, the rear end surface of the tire tread rubber enters the state of view of the second photographing means. Therefore, the first photographing means and the second photographing means can simultaneously photograph the front end face and the rear end face of the tire tread rubber in the conveyance process.
In addition, as described above, since the detection means for transmitting the trigger signal for starting the shutter synchronized with the first and second imaging means is provided when the passage of the front end surface of the tire tread rubber is detected, the trigger is provided. The first photographing means and the second photographing means that have received the signal can reliably capture and simultaneously photograph the front end face and the rear end face of the tire tread rubber.
In addition, it is preferable that the trigger signal is transmitted at a timing so that the front end surface and the rear end surface of the tire tread rubber are located within a range of about 50 mm before and after the reference line of the first and second imaging means during imaging.

  Further, as described above, the front end surface and the rear end surface of the tire tread rubber are irradiated with light at the time of shooting, and the inclined surfaces and the upper end edge of the front end surface, the rear end surface are clearly distinguished over the entire length in the width direction. The first and second illuminating means are provided with the first and second illuminating means. When the front and rear end surfaces of the tire tread rubber are irradiated with light, the upper ends of the first and second illuminating units extend over the entire length in the width direction. It is preferable that the edges are arranged and irradiated so that the edges are sharpened as light and dark border lines.

  As described above, the first and second illumination means clearly identify the inclined surfaces of the front end surface and the rear end surface and the upper end edge over the entire length in the width direction, and the upper end edge in the photographed front end image and rear end image. 2 is detected as an edge line extending over the entire length in the width direction, so that the tire tread rubber is conveyed obliquely with respect to the traveling direction (arrow direction) of the conveyor as shown in FIG. Further, the length of the tire tread rubber is corrected from the inclination angle θ, and the length L of the tire tread rubber can be calculated with high accuracy (see Formula 1).

The first and second photographing means are digital or analog cameras, the reference line of the first photographing means and the reference line of the second photographing means are lines that are the center of the visual field of the camera of each photographing means, and
The detection means comprises a transmissive phototube,
The first and second illumination means comprise LED bar illumination,
The second photographing means is preferably installed so as to be movable according to the length of the tire tread rubber.

  As described above, it is preferable that the first and second photographing means are composed of digital or analog shutter cameras. In particular, the upper edge is clearly detected, and high-precision distance measurement can be performed at a good processing speed. As described above, it is preferable to use a high-resolution camera using a CCD with 1 to 3 million pixels. Moreover, it is preferable that the imaging | photography range (camera visual field on a conveyor) of the camera of a 1st, 2nd imaging | photography means will be about 300 mm-400 mm x 400 mm-500 mm in length.

  Further, as described above, the reference line of the first photographing means and the reference line of the second photographing means are the lines that are the center of the visual field of the camera of each photographing means, so that the timing is taken with reference to the reference line. When taking a picture, it is possible to prevent the front end face and rear end face of the tire tread rubber to be photographed from being out of the field of view of the camera. It is possible to shoot a clear image without any problem. Therefore, the length of the tire tread rubber can be measured with higher accuracy.

  In addition to the transmission type photoelectric tube, a reflection type photoelectric tube, a displacement meter, an image sensor, and the like can be used as the detection means. However, the transmission type photoelectric tube has a high response speed, and can reliably shoot. Since timing can be taken, it is preferably used.

In addition, as described above, it is preferable that the first and second illumination means be LED bar illuminations, because the LED bar illuminations are arranged with high density of LEDs, and can irradiate light uniformly over a wide area. Therefore, the upper end edge can be sharpened over the entire length in the width direction.
Furthermore, as described above, by installing the second photographing means so as to be movable according to the length of the tire tread rubber, it is possible to correspond to the measurement of the length of the tire tread rubber having a different specification length.

The inclination of the front and rear end surfaces of the tire tread rubber is an inclined surface inclined backward from the upper end to the lower end,
The first illuminating means is arranged to be inclined downward by 40 to 50 degrees toward the tire tread rubber conveyed by a conveyor at the upper rear part of the first photographing means, while the second illuminating means is the second illuminating means. Arranged in the horizontal direction toward the tire tread rubber that is being conveyed by the conveyor at the upper back of the imaging means,
The first photographing means obtains a front end image that can identify the inclined inclined surface and the upper edge that emits white light,
It is preferable that the second photographing unit obtains a rear end image that can distinguish between the inclined surface emitting white light and the shaded upper end edge.

Normally, the tire tread to be conveyed has an acute angle between the inclined surface as the front end surface and the upper surface, and an obtuse angle between the inclined surface as the rear end surface and the upper surface. In such a case, as described above, the first illuminating unit is disposed at an inclination angle of 40 to 50 degrees obliquely downward toward the front end surface of the tire tread rubber being conveyed by the conveyor at the upper rear portion of the first photographing unit. By arranging and irradiating, the inclined surface of the front end surface forming an acute angle with the upper surface can be shaded, and the upper surface including the entire length of the upper edge can be whitened. Therefore, the upper end edge which makes a boundary with the inclined surface which becomes a shadow can be sharpened over the entire length in the width direction.
The irradiation range of the first illumination unit is not particularly limited as long as the entire imaging range of the first imaging unit can be uniformly irradiated. For example, the imaging range of the first imaging unit (viewing field on the conveyor) is 350 mm wide × long If it is 450 mm, it is preferable that the irradiation range of the first illumination means is a range of width 300 mm × length 400 mm that covers the imaging range.

On the other hand, as described above, the second illumination means forms an obtuse angle with the upper surface by irradiating the second illumination means in the horizontal direction toward the tire tread rubber conveyed by the conveyor on the upper part behind the second photographing means. The inclined surface of the rear end surface can be halated white, and the upper surface including the entire length of the upper end edge can be shaded. Therefore, it is possible to sharpen the upper edge that forms a boundary with the inclined surface that emits white light over the entire length in the width direction.
The irradiation range of the second imaging unit is not particularly limited as long as the entire imaging range of the second imaging unit can be uniformly irradiated. For example, the imaging range (viewing field on the conveyor) of the second imaging unit is 350 mm wide × length. If it is 450 mm, it is preferable that the irradiation range of the second illumination means is a range of width 300 mm × length 400 mm covering the imaging range.

  The arithmetic processing unit divides the front end image and the rear end image into a plurality of segments in the width direction of the tire tread rubber, and an average value of distances from the upper end edge of the front end image to the reference line of the first photographing unit in each segment The length of the tire tread rubber can be obtained by setting L1 as the above and L2 as an average value of the distance from the upper end edge of the rear end image in each segment to the reference line of the second photographing means.

As described above, the front end image and the rear end image are divided into a plurality of segments in the width direction of the tire tread rubber, and the distances from the upper end edge of the front end image to the reference line of the first photographing means in each segment (L11, L12, .., L1n) is an average value [(L11 + L12 +... + L1n) / n], and the distance (L21, L22,...) From the upper edge of the rear end image to the reference line of the second photographing means in each segment. ..., the length of the tire tread rubber can be obtained by calculating the length of the tire tread rubber using the average value [(L21 + L22 + ... + L2n) / n] of L2n) as L2. it can.
In addition, as the distance (L11, L12,..., L1n, L21, L22,..., L2n) from the upper edge to the reference line in each segment, for example, the distance at the center position in the width direction of each segment. Can be used.

  Further, in the tread rubber having a large difference between the thickest portion and the thin portion of the tread gauge, the cut cross section may meander due to the difference in shrinkage after cutting. In such a case, the average value is L1, Instead of L2, focus on the segment at the center position (tread center) in the width direction of the front end image and the rear end image, and the distance from the upper end edge to the reference line in the segment is L1 and L2, respectively. It is also possible to calculate the length of the tire tread rubber by paying attention to the segment of the thickest part of the tread gauge and by using the distances from the upper edge to the reference line in the segment as L1 and L2, respectively.

Thus, by measuring the length of the tire tread rubber by appropriately changing the segment of interest depending on the shape of the tire tread rubber to be measured, it is possible to obtain a highly accurate tire tread rubber length with little variation. it can.
In addition, the segment width divided | segmented into the width direction of tire tread rubber is although it does not specifically limit, For example, it can be set as about 20 mm-40 mm.

  As described above, according to the present invention, the front end surface and the rear end surface of the tire tread rubber in the conveyance process can be simultaneously photographed by the first photographing unit and the second photographing unit capable of photographing over the entire length in the width direction. From the photographed front end image and rear end image, the distance (L1) between the reference line of the first image capturing means and the upper end edge of the front end image, and the distance (L2) between the reference line of the second image capturing means and the upper end edge of the rear end image. ) And calculating the length of the tire tread rubber by simply adding each distance (L1, L2) to the distance between the reference lines of the first and second imaging means. In particular, in the present invention, since the first illumination means and the second illumination means clearly distinguish the slopes and the upper edge of the front end face and the rear end face over the entire length in the width direction at the time of shooting. In the rear end image, the upper end edge can be detected as an edge line extending over the entire length in the width direction. Accordingly, the distance (L1) between the reference line of the first photographing unit and the upper end edge of the front end image and the reference line of the second photographing unit, for example, by taking an average distance by the amount of detection points of the upper end edge significantly increasing. And the distance (L2) between the rear end image and the upper end edge of the rear end image can be calculated with high accuracy. Therefore, the length of the tire tread rubber can also be calculated with high accuracy.

  Further, as described above, the first and second illumination means clearly distinguish the inclined surfaces and the upper end edge of the front end surface and the rear end surface over the entire length in the width direction, and in the photographed front end image and rear end image, By detecting the upper edge as an edge line extending over the entire length in the width direction, even if the tire tread rubber is conveyed in an oblique direction with respect to the traveling direction of the conveyor, the length of the tire tread rubber is determined from the inclination angle θ. Can be corrected, and the length L of the tire tread rubber can be calculated with high accuracy.

  Further, as described above, by dividing the front end image and the rear end image into a plurality of segments in the width direction of the tire tread rubber, the tire tread rubber using the average value of the distance from the upper end edge to the reference line in each segment. Calculate the length of the tire tread rubber using the distance from the upper edge to the reference line in the segment, focusing on the tread center segment of the front end image and the rear end image, or Focusing on the segment of the thickest portion of the tread gauge, the length of the tire tread rubber can be calculated using the distance from the upper edge to the reference line in the segment. That is, by measuring the length of the tire tread rubber by appropriately changing the segment of interest depending on the shape of the tire tread rubber to be measured, it is possible to obtain a highly accurate tire tread rubber length with little variation.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 6 show an embodiment of the present invention.
The tire tread rubber 30 measured by the tire tread rubber length measuring device 10 shown in FIG. 1 is cut into a predetermined length (specification length 1900 mm in the present embodiment), and the cut front end face 31 and rear end face are cut. Reference numeral 32 denotes a long sheet having an inclined surface. The front end surface 31 and the upper surface 33 form an acute angle, and the rear end surface 32 and the upper surface 33 form an obtuse angle. In the process of placing the tire tread rubber 30 horizontally on the conveyor 11 and transporting the tire tread rubber 30 in the direction of the arrow in FIG. 1, using the tire tread rubber length measuring device 10, the length L (front end surface) of the tire tread rubber 30 is measured. The distance between the upper end edge 34 of 31 and the upper end edge 35 of the rear end face 32 is measured.

Hereinafter, the configuration of the tire tread rubber length measuring device 10 will be described.
The tire tread rubber length measuring device 10 includes a camera 12 serving as a first photographing unit that photographs the tire tread rubber front end face 31 over the entire length in the width direction by fixing the tire tread rubber length above the conveyor 11, and the rear end face 32 in the width direction full length. The camera 13 of the 2nd imaging | photography means which image | photographs over is provided.
The camera 13 of the second photographing means is positioned at a distance (1900 mm in the present embodiment) corresponding to the length of the tire tread rubber 30 away from the first photographing means 12 on the upstream side in the transport direction. The camera 13 of the photographing means is movable in the front-rear direction according to the length of the tire tread rubber to be measured.

The cameras 12 and 13 of the first and second photographing means are connected to the controller 20, the controller 20 is connected to the CPU 21, the cameras 12 and 13 are operated by the controller 20, and the images are taken by the cameras 12 and 13. The front end image 41 and the rear end image 42 are captured and an image signal is transmitted to the CPU 21. The CPU 21 calculates the length of the tire tread rubber from the front end image 41 and the rear end image 42.
In the present embodiment, the photographing range of the cameras 12 and 13 of the first and second photographing means (the field of view of the cameras 12 and 13 on the conveyor 11) is 350 mm wide × 450 mm long. It is installed at a position 500 mm above the conveyor 11.
In addition, the visual field centers of the cameras 12 and 13 of the first and second photographing means are set as a reference line R1 of the first photographing means 12 and a reference line R2 of the second photographing means 13, respectively.

  As detection means for detecting the passage of the front end face 31 of the tire tread rubber 30 and transmitting a shutter start trigger signal in synchronization with the cameras 12 and 13 of the first and second imaging means, the first and second imaging means A transmissive photoelectric tube 14 is disposed downward between the cameras 12 and 13 and at a position close to the camera 12 of the first photographing means (position 200 mm behind the reference line R1 in this embodiment). A light source 15 for projecting light onto the phototube 14 is disposed upward between the rollers 11a constituting the conveyor 11 at the facing position. A timer 16 is connected to the phototube 14 and is connected to the controller 20 via the timer 16.

In the upper part of the rear of the camera 12 of the first photographing means, a slanting downward toward the tire tread rubber 30 being conveyed and an inclination angle θ1 = 40 to 50 degrees (in this embodiment, θ1 = 45 degrees) The LED bar illumination 17 of 1 illumination means is arranged.
The LED bar illumination 18 of the second illuminating means is disposed in the horizontal direction toward the tire tread rubber 30 being conveyed at the upper rear portion of the camera 13 of the second photographing means.
The LED bar lights 17 and 18 of the first and second illumination means are connected to an illumination controller 19.

In the present embodiment, the irradiation range of the LED bar illumination 17 of the first illuminating means is a range of width 300 mm × length 500 mm that covers the photographing range of the camera 12 of the first photographing means. The irradiation range of the LED bar illumination 18 of the second illumination means is a range of width 300 mm × length 400 mm that covers the shooting range of the camera 13 of the second imaging means.
The LED bar illumination 17 of the first illumination means is installed at a position 100 mm behind the reference line R1 of the first imaging means 12 and 100 mm above the conveyor 11.
The LED bar illumination 18 of the second illumination means is installed at a position 150 mm behind the reference line R <b> 2 of the second imaging means 12 and 60 mm above the conveyor 11.

As described above, the CPU 21 receives the image signals of the front end image 41 and the rear end image 42 taken by the cameras 12 and 13 of the first and second photographing means, and the reference line R1 of the camera 12 of the first photographing means. The distance L1 between the upper end edge 44 of the front end image 41 and the distance L2 between the reference line R2 of the camera 13 of the second photographing means and the upper end edge 45 of the rear end image 42 are respectively calculated, and the length of the tire tread rubber 30 is calculated. There is provided an arithmetic processing unit for calculating.
The CPU 21 is connected to the monitor 22 and displays the length L of the tire tread rubber 30 obtained by the arithmetic processing unit on the monitor 22.

  Hereinafter, measurement of the tire tread rubber 30 length L using the above-described tire tread rubber length measuring device 10 will be described.

As shown in FIG. 1, the tire tread rubber 30 that is horizontally placed on the conveyor 11 and conveyed in the direction of the arrow has its front end surface 31 passing under the photoelectric tube 14 so that light from the light source 15 is applied to the tire tread rubber 30. Since it is blocked, the photoelectric tube 14 detects the passage of the front end face 31.
When the front end face 31 is detected, the phototube 14 transmits an ON signal to the timer 16 and is delayed by a predetermined time by the timer 16, and then a synchronized shutter start trigger signal is sent to the cameras 12 and 13 of the first and second photographing means. It transmits to the controller 20 connected.
In the present embodiment, the timing is set so that the front end surface 31 and the rear end surface 32 of the tire tread rubber 30 are positioned within a range of 50 mm before and after the reference lines R1 and R2 of the first and second imaging means at the time of shooting. A trigger signal is sent. The cameras 12 and 13 of the first and second photographing means perform photographing simultaneously with the trigger input.

At the time of photographing, the LED bar lights 17 and 18 of the first and second illumination means irradiate light to the front end and the rear end surface 32 of the tire tread rubber 30 as described above. The inclined surface of the front end surface 31 and its upper end edge 34, and the inclined surface of the rear end surface 32 and its upper end edge 35 are clearly identified.
Specifically, since the LED bar illumination 17 of the first illumination means irradiates light obliquely downward with respect to the front end, the inclined surface of the front end surface 31 that forms an acute angle with the upper surface 33 as shown in FIG. The upper surface 33 including the entire length of the upper end edge 34 is white and halated. Therefore, the upper end edge 34 that forms a boundary with the inclined surface of the front end surface 31 that is a shadow is sharpened over the entire length in the width direction.
On the other hand, since the LED bar illumination 18 of the second illuminating means irradiates light in the horizontal direction with respect to the rear end surface 32, the inclined surface of the rear end surface 32 that forms an obtuse angle with the upper surface 33 is white as shown in FIG. The upper surface 33 that is halated and includes the entire length of the upper edge 35 is shaded. Therefore, the upper edge 35 that forms a boundary with the inclined surface of the rear end surface 32 that emits white light is sharpened over the entire length in the width direction.

  Therefore, as shown in FIG. 5, the front end image 41 photographed by the camera 12 of the first photographing means becomes an image in which the upper end edge 44 can be detected over the entire length in the width direction as an edge line, and is photographed by the camera 13 of the second photographing means. As shown in FIG. 6, the rear end image 42 is also an image in which the upper end edge 45 can be detected over the entire length in the width direction as an edge line.

  The front end image 41 and the rear end image 42 taken by the cameras 12 and 13 are transmitted as image data to the CPU 21 via the controller 20, and the CPU 21 calculates the image data of the received front end image 41 and rear end image 42. Process.

First, as shown in FIGS. 5 and 6, the front end image 41 and the rear end image 42 are divided into a plurality of segments S1 to Sn in the width direction of the tire tread rubber. In the present embodiment, the front end image 41 and the rear end image 42 having a tread width of 150 mm are divided into five segments S1 to S5 having a segment width of 30 mm.
Furthermore, the average value L1 [L1 = (L11 + L12 +... + L1n) / n] of the distances (L11, L12,..., L1n) from the upper edge 44 to the reference line R1 in each segment S1 to Sn of the front end image 41. The average value L2 [L2 = (L21 + L22 +... + L2n) / n] of the distances (L21, L22,..., L2n) from the upper edge 45 to the reference line R2 in each segment S1 to Sn of the rear end image 42. Are calculated respectively.

  In the present embodiment, the distances (L11, L12,..., L1n, L21, L22,..., L2n) from the upper edge 44, 45 to the reference lines R1, R2 in each segment S1 to Sn The distance at the center position in the width direction of S1 to Sn is used. Further, when the upper edge 44, 45 is positioned between the reference lines R1, R2, the distance from the upper edge 44, 45 to the reference line R1, R2 is a positive value, and the upper edge 44, 45 is between the reference lines. The distance when it is not located at is a negative value.

  Therefore, the length L of the tire tread rubber 30 is calculated as follows when the tire tread rubber 30 is conveyed in parallel with the traveling direction of the conveyor 11 as shown in FIG. Calculated using the following formula: L = L3-L1-L2 (L3: distance between reference lines R1 and R2), and the tire tread rubber 30 is inclined with respect to the traveling direction of the conveyor 11 as shown in FIG. In the case of being conveyed at an incline, it is calculated by Equation 1 using the calculated average values L1 and L2. By displaying the calculated length L of the tire tread rubber 30 on the display monitor 22, the measurement of the length of one tire tread rubber 30 is completed.

On the other hand, when the tire tread rubber 30 has a large difference between the thickest portion and the thin portion of the tread gauge and the cut cross section greatly meanders due to the difference in shrinkage after cutting, the center position in the width direction of the front end image and the rear end image Paying attention to the segment Sc of (tread center), the length L of the tire tread rubber 30 is calculated with the distances L1c and L2c from the upper end edges 44 and 45 to the reference lines R1 and R2 in the segment Sc of the tread center as L1 and L2, respectively. You can also
Further, paying attention to the segment of the thickest part of the tread gauge, the length L of the tire tread rubber can be calculated with the distances from the upper edge to the reference line in the segment as L1 and L2, respectively.

  As described above, according to the present invention, the front end surface 31 and the rear end surface 32 of the tire tread rubber 30 in the process of being conveyed by the camera 12 of the first image capturing unit and the camera 13 of the second image capturing unit that can capture the entire length in the width direction. Can be photographed simultaneously, the distance L1 between the reference line R1 of the first photographing means 12 and the upper edge 44 of the front end image 41 and the second photographing means 13 from the photographed front end image 41 and rear end image 42. A calculation is performed to calculate the distance L2 between the reference line R2 and the upper edge 45 of the rear end image 42 and add the distances L1 and L2 to the distance L3 between the reference lines R1 and R2 of the first and second imaging means 12 and 13. Only by doing this, the length L of the tire tread rubber 30 can be easily obtained.

In particular, during photographing, the LED bar illumination 17 of the first illumination unit and the LED bar illumination 18 of the second illumination unit clearly identify the slopes of the front end surface 31 and the rear end surface 32 and the upper end edges 34 and 35 over the entire length in the width direction. Therefore, in the photographed front end image 41 and rear end image 42, the upper end edges 44 and 45 can be detected as edge lines extending over the entire length in the width direction.
Accordingly, the distance L1 between the reference line R1 of the first photographing means 12 and the upper end edge 44 of the front end image 41 and the second photographing means are obtained by taking an average distance by the amount of detection points of the upper end edges 44 and 45 being significantly increased. The distance L2 between the thirteen reference lines R2 and the upper end edge 45 of the rear end image 42 can be calculated with high accuracy. Therefore, the length L of the tire tread rubber 30 can also be calculated with high accuracy.

  Further, as described above, the inclined surfaces of the front end surface 31 and the rear end surface 32 and the upper end edges 34 and 35 are clearly identified over the entire length in the width direction by the LED bar lights 17 and 18 of the first and second illumination means. In the captured front end image 41 and rear end image 42, the upper end edges 44 and 45 can be detected as edge lines extending over the entire length in the width direction. Therefore, even when the tire tread rubber 30 is conveyed obliquely with respect to the traveling direction of the conveyor 11, the length L of the tire tread rubber 30 is corrected by correcting the length L of the tire tread rubber 30 from the inclination angle θ. The length L can be calculated with high accuracy.

  Further, as described above, the front end image 41 and the rear end image 42 are divided into a plurality of segments S1 to Sn in the width direction of the tire tread rubber 30, so that the reference lines are drawn from the upper end edges 44 and 45 in each segment S1 to Sn. The length L of the tire tread rubber 30 can be calculated using the average values of the distances L11 to L1n and L21 to L2n to R1 and R2 as L1 and L2.

In some cases, attention is paid to the tread center segment Sc of the front end image 41 and the rear end image 43, and the distances L1c and L2c from the upper end edges 44 and 45 to the reference lines R1 and R2 in the segment Sc are set as L1 and L2. The length L of the tire tread rubber 30 can be calculated. Alternatively, focusing on the segment of the thickest part of the tread gauge, the length L of the tire tread rubber 30 can be calculated with the distances from the upper edge to the reference line in the segment as L1 and L2.
That is, by measuring the length L of the tire tread rubber 30 by appropriately changing the segment of interest depending on the shape of the tire tread rubber 30 to be measured, the length L of the highly accurate tire tread rubber 30 with little variation is obtained. Obtainable.

  Examples of the tire tread rubber length measuring device according to the present invention and comparative examples will be described below.

[Example 1]
In Example 1, measurement of the tread length was repeated 100 times using a tire tread rubber having a tread length (tread center length) of 1900 mm.
The measurement apparatus and the measurement method were the same as those in the above embodiment, and the length of the tire tread rubber was measured as L1 and L2 divided into the following two types (1) and (2).
(1) When using the average value (L11 + L12 + L13 + L14 + L15) / 5 and (L21 + L22 + L23 + L24 + L25) / 5 of the distance from the upper edge to the reference line in each segment (S1 to S5) (2) The reference line from the upper edge in the center segment (S3) Table 1 shows the measurement results.

The cameras of the first and second photographing means and the LED bar illuminations of the first and second illumination means used in the embodiment and Example 1 are as follows.
・ Camera: 2 million pixel monochrome CCD camera, product name CV-200M (manufactured by Keyence)
LED bar lighting: White LED bar lighting, trade name CA-DBW13 (manufactured by Keyence)

[Comparative Example 1]
In Comparative Example 1, measurement was performed using the same measurement apparatus as that of Patent Document 1 which is a conventional technique.
That is, as shown in FIGS. 7A to 7C, the slit light S is projected from the light projector 6 so as to intersect the lower edge 2 of the tire tread rubber 1, and the lower surface 3 sandwiching the lower edge 2 is inclined. The image of the unit 4 is taken into the image processing device 5, the inclined inflection point Sa of the projected slit light S is determined as the lower edge 2, and the distance a between the inflection point Sa and the reference position of the camera 7 is calculated. And the length L of the tire tread rubber 1 was calculated | required from numerical formula L = a + b + c.
b: Distance from the rear end detector inputted in advance to the reference position of the camera 7,
c: Offset distance Others were the same as in Example 1. The measurement results are shown in Table 1.

As is apparent from Table 1, in Example 1 measured using the tire tread length measuring device of the present invention, the average value is extremely true (1900 mm) in both cases (1) and (2). It was confirmed that the tire tread length can be measured with high accuracy because the standard deviation is as small as 0.23 mm or less.
On the other hand, in Comparative Example 1, the average value greatly deviated from the true value (1900 mm), and the standard deviation was also 2.9 mm, and the variation was large.

It is the schematic which shows the measuring apparatus of the tire tread rubber length of this embodiment. A plan view when measuring the length of the tire tread rubber, (A) is when the tire tread rubber is conveyed in parallel with the traveling direction of the conveyor, (B) is inclined with respect to the traveling direction of the conveyor. It is a figure which shows the case where it is conveyed. The tire tread rubber | gum on the front end surface side at the time of the 1st illumination means irradiating light is shown, (a) is a side view, (b) is a top view. The tire tread rubber of the rear-end surface side at the time of the 2nd illumination means irradiating light is shown, (a) is a side view, (b) is a top view. It is explanatory drawing of a front end surface image. It is explanatory drawing of a rear end surface image. It is drawing which shows a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Tire tread rubber length measuring device 11 Conveyor 12 1st imaging | photography means (camera)
13 Second photographing means (camera)
14 Phototube 15 Light source 16 Timer 17 First illumination means (LED bar illumination)
18 Second illumination means (LED bar illumination)
19 Lighting controller 20 Controller 21 CPU
22 Monitor 30 Tire tread rubber 31 Front end surface 32 Rear end surface 33 Upper surface 34, 35 Upper end edge 41 Front end image 42 Rear end image 44, 45 Upper end edge

Claims (4)

In the process of placing the tire tread rubber in the form of a long sheet, which is cut to a required length and the cut front end face and rear end face are inclined surfaces, horizontally placed on a conveyor, the tire tread rubber A device for measuring length,
A first photographing means for photographing the front end face over the entire length in the width direction, fixed above the conveyor, and a dimension corresponding to the length of the tire tread rubber upstream from the first photographing means in the conveying direction; A second imaging means for positioning the rear end face over the entire length in the width direction;
When the passage of the front end surface, which is the front end side in the conveyance direction of the tire tread rubber, is detected between the first imaging unit and the second imaging unit and in the vicinity of the first imaging unit, the first, Detection means for transmitting a shutter start synchronization trigger signal to the second photographing means;
When photographing from above with the first and second photographing means, the front end surface and the rear end surface of the tire tread rubber are irradiated with light, and the inclined surfaces and the upper end edges of the front end surface and the rear end surface are made to have an overall length in the width direction. A first illumination means and a second illumination means for clearly distinguishing over
The front end image and the rear end image of the tire tread rubber photographed by the first and second photographing means are captured, and the distance (L1) between the reference line of the installation position of the first photographing means and the upper edge of the front end image And the distance (L2) between the reference line of the installation position of the second photographing means and the upper edge of the rear end image in addition to the distance between the reference lines of the first and second photographing means, and the tire tread rubber Arithmetic processing means for obtaining the length of the tire, and display means for displaying the length of the tire tread rubber obtained by the arithmetic processing means,
An apparatus for measuring the length of a tire tread rubber, comprising: The first and second photographing means are digital or analog cameras, the reference line of the first photographing means and the reference line of the second photographing means are lines that are the center of the visual field of the camera of each photographing means, and
The detection means comprises a transmissive phototube,
The first and second illumination means comprise LED bar illumination,
The tire tread rubber length measuring device according to claim 1, wherein the second photographing means is installed so as to be movable according to the length of the tire tread rubber. The inclination of the front and rear end surfaces of the tire tread rubber is an inclined surface inclined backward from the upper end to the lower end,
The first illuminating means is arranged to be inclined downward by 40 to 50 degrees toward the tire tread rubber conveyed by a conveyor at the upper rear part of the first photographing means, while the second illuminating means is the second illuminating means. Arranged in the horizontal direction toward the tire tread rubber that is being conveyed by the conveyor at the upper back of the imaging means,
The first photographing means obtains a front end image that can identify the inclined inclined surface and the upper edge that emits white light,
3. The tire tread rubber length measuring device according to claim 1, wherein a rear end image capable of distinguishing an inclined surface that emits white light and a shadow upper end edge is acquired by the second photographing unit. 4.   The image processing means divides the front end image and the rear end image into a plurality of segments in the width direction of the tire tread rubber, and an average value of the distance from the upper end edge of the front end image to the reference line of the first photographing means in each segment The tire tread according to any one of claims 1 to 3, wherein L1 is L1, and an average value of the distance from the upper end edge of the rear end image in each segment to the reference line of the second photographing unit is L2. Rubber length measuring device.

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