Rubber product and measurement method

Abstract

This rubber product (30) has: a groove part provided on the surface of rubber; and a pattern for three-dimensional measurement provided on the bottom surface of the groove part.

Description

Rubber products and measurement methods

[0001] The present disclosure relates to rubber products and measurement methods.

[0002] 2. Description of the Related Art Conventionally, pneumatic tires have been known in which groove walls are provided with ridges made up of a plurality of protrusions or depressions that are inclined in one direction relative to the longitudinal direction of the groove (see, for example, Patent Document 1).

[0003] WO 2004 / 048130

[0004] In conventional technology, when photographing rubber products such as tires or rubber crawlers to generate three-dimensional data, it has been difficult to generate three-dimensional data about the bottoms of grooves on the surface of the rubber product. For example, projecting a laser pattern and photographing it requires expensive equipment, and applying a characteristic pattern to the rubber product by painting or other methods has been difficult, as it is difficult to paint even the narrow grooves. Furthermore, when using the generated three-dimensional data to examine the differences between a worn product and a new rubber product, there is no reference point for aligning the coordinates of the three-dimensional data, making comparison difficult.

[0005] The present disclosure was made in consideration of the above circumstances and aims to improve the technology for converting rubber products into three-dimensional data and for measuring rubber products using the three-dimensional data.

[0006] The gist of the present disclosure for solving the above problems is as follows.

[0007] (1) A rubber product having a groove provided on a surface of the rubber, and a pattern for three-dimensional measurement provided on the bottom surface of the groove.

[0008] (2) The rubber product according to (1) above, wherein the pattern is a random pattern.

[0009] (3) The rubber product according to (1) or (2) above, wherein the pattern is a three-dimensional pattern.

[0010] (4) The rubber product according to any one of (1) to (3) above, wherein the pattern includes letters.

[0011] (5) The rubber product according to any one of (1) to (4) above, wherein the rubber is a tire or a crawler.

[0012] (6) A computer-implemented method for measuring a rubber product, wherein the rubber product has a groove provided on the surface of the rubber and a pattern for three-dimensional measurement provided on the bottom surface of the groove, and the method includes measuring wear of the rubber product based on the three-dimensional data of the rubber product.

[0013] (7) The measurement method according to (6) above, further comprising calculating the amount of wear of the rubber product based on the difference in position between the bottom surface and the surface before wear.

[0014] (8) The measurement method according to (7) above, comprising: aligning the three-dimensional data of the new rubber product with the three-dimensional data of the worn rubber product based on the pattern; and calculating the difference after the alignment to measure the wear.

[0015] (9) The measurement method according to any one of (6) to (8) above, further comprising generating a wear map showing the measured wear in three dimensions.

[0016] According to one embodiment of the present disclosure, it is possible to improve the three-dimensional data generation of rubber products and the measurement technology using the three-dimensional data.

[0017] FIG. 1 is a schematic diagram showing the configuration of a measurement system; FIG. 2 is a diagram showing an example of the configuration of a rubber product; FIG. 3 is a diagram for explaining an example of a pattern; FIG. 4 is a flowchart showing an operation executed by the measurement device; FIG. 5 is a diagram for explaining an example of generated three-dimensional data; FIG. 6 is a diagram showing an example of three-dimensional data superimposed on each other; and FIG. 7 is a diagram for explaining an example of a wear map.

[0018] Hereinafter, one embodiment will be described in detail with reference to the drawings.

[0019] 1 shows an example of the configuration of a measurement system 1 according to one embodiment. The measurement system 1 includes a measurement device 10, a camera 20, and a rubber product 30 to be measured. The measurement device 10 and the camera 20 are connected via a network 40.

[0020] The camera 20 is a three-dimensional camera such as a stereo camera or a ToF (Time of Flight) camera. The camera 20 is capable of transmitting an image of the rubber product 30 to the measuring device 10 via the network 40.

[0021] The rubber product 30 includes a tire, a crawler, or the like. This enables more accurate generation of three-dimensional data and alignment of the three-dimensional data for tires or crawlers with fewer feature points, as described below. In this embodiment, the rubber product 30 is a tire. Tires include tires for vehicles, motorcycles, bicycles, airplanes, and the like. The tire may also be an OR (Off-The-Road) tire mounted on a construction vehicle, mining vehicle, or the like. The rubber product 30 has grooves G on its rubber surface and a three-dimensional measurement pattern on the bottom surface GS of the grooves G. The pattern is extracted as a feature point in an image captured by a camera 20 or the like, facilitating the creation of three-dimensional data. For example, it is possible to reconstruct and generate highly accurate three-dimensional data based on the feature points from images captured from multiple fields of view using a three-dimensional camera or the like. Furthermore, the pattern enables accurate alignment of the three-dimensional data of the rubber product 30 before and after wear, as described below. As described above, according to this embodiment, it is possible to improve the accuracy when three-dimensional data including the pattern as a feature point is used for measuring wear, etc.

[0022] The network 40 may include the Internet, at least one Wide Area Network (WAN), at least one Metropolitan Area Network (MAN), or a combination thereof. The network 40 may also include at least one wireless network, at least one optical network, or a combination thereof.

[0023] <Measuring Device 10 > The measuring device 10 includes a control unit 11, a storage unit 12, a communication unit 13, and an input / output unit 14.

[0024] The control unit 11 includes at least one processor, at least one dedicated circuit, or a combination of these. The processor is a general-purpose processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), or a dedicated processor specialized for a specific process. The dedicated circuit is, for example, an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit). The control unit 11 controls each part of the measurement device 10 and executes processes related to the operation of the measurement device 10.

[0025] The storage unit 12 includes at least one semiconductor memory, at least one magnetic memory, at least one optical memory, or a combination of at least two of these. The semiconductor memory is, for example, a random access memory (RAM) or a read-only memory (ROM). The RAM is, for example, a static random access memory (SRAM) or a dynamic random access memory (DRAM). The ROM is, for example, an electrically erasable programmable read-only memory (EEPROM). The storage unit 12 functions as, for example, a main storage device, an auxiliary storage device, or a cache memory. The storage unit 12 stores any information, control / processing programs, etc. used in the operation of the measuring device 10, as well as information obtained by the operation of the measuring device 10.

[0026] The communication unit 13 includes at least one communication interface. The communication interface is, for example, a LAN interface, an interface compatible with a mobile communication standard such as the 4th Generation (4G) standard or the 5th Generation (5G) standard, an interface compatible with short-range wireless communication such as Bluetooth (registered trademark), or a LAN interface. The communication unit 13 receives information used in the operation of the measurement device 10 and transmits information obtained by the operation of the measurement device 10.

[0027] The input / output unit 14 includes at least one input / output interface. The input / output interface includes a touch screen integrated with a display. The input / output unit 14 accepts input operations for information used in the operation of the measuring device 10 and outputs information obtained by the operation of the measuring device 10. The input / output unit 14 may be connected to the measuring device 10 as an external input device instead of being provided in the measuring device 10. Any connection method, such as a Universal Serial Bus (USB), can be used. The input / output unit 14 may not be integrated, but may instead be composed of separate input and output units. In this case, the input unit includes at least one input interface, such as physical keys or a microphone. The output unit includes at least one output interface, such as a display or a speaker.

[0028] <Rubber Product 30> With reference to Figure 2, the configuration of a tire as a rubber product 30 according to this embodiment will be described. The tire includes a surface S and grooves G provided on the surface S. In Figure 2, a plurality of grooves G are provided at both ends of the tire tread, but the position and number of grooves G are not limited to this and may be provided, for example, in the circumferential direction of the tire. The position and number of grooves G may vary depending on the type or size of the tire. Z1 in Figure 2 shows a partially enlarged view of the surface S of the tire. Z2 in Figure 2 shows a schematic enlarged view of a cross section of a groove G. As shown in Z2, the groove G has a bottom surface GS, and a pattern for three-dimensional measurement is provided on the bottom surface GS. In this embodiment, the bottom surface GS is a surface that is approximately horizontal with respect to the surface S, but it may also be a surface that has an inclination.

[0029] Each of Figures 3A to 3D shows an enlarged example of a pattern provided on the bottom surface GS. Figure 3A shows an example of a diagonal line pattern. Figure 3B shows an example of a checkerboard pattern. Figures 3C and 3D each show a circular pattern. Figure 3C is a pattern in which each circle has a convex shape. Figure 3D is a pattern in which each circle has a concave dimple.

[0030] The pattern may have a three-dimensional shape. This allows the pattern to be photographed more accurately when a three-dimensional camera is used to generate three-dimensional data. Therefore, it becomes possible to provide effective feature points on the bottom surface by generating three-dimensional data and aligning the three-dimensional data. In this case, any method such as injection molding or press molding may be used to provide the pattern. However, the method is not limited to this, and the pattern may also be provided by applying a coloring process.

[0031] At least a portion of the pattern may be randomly configured. This allows different patterns to be provided for each bottom surface of multiple grooves provided in a rubber product. Therefore, by generating three-dimensional data and aligning the three-dimensional data, it becomes possible to provide effective feature points on the bottom surface. For example, in the diagonal line pattern of FIG. 3A, one or a combination of the spacing between the diagonal lines, the color of each diagonal line or the area surrounded by the diagonal lines, the thickness of each diagonal line, the angle of inclination of each diagonal line, etc. may be randomly configured. For example, in the checkered pattern of FIG. 3B, one or a combination of the size of the area of ​​each grid, the color of each grid line or the area surrounded by the grid lines, the thickness of each grid line, the angle of inclination of each grid line, etc. may be randomly configured. For example, in the circular patterns of FIG. 3C and FIG. 3D, one or a combination of the spacing between the circles, the color of each circle, the area of ​​each circle, the arrangement of each circle, etc. may be randomly configured. The pattern is not limited to circles, and may be composed of polygons.

[0032] The patterns are not limited to the geometric designs shown in A to D of FIG. 3, but may include logos and patterns representing characters such as animals, plants, and humans.

[0033] The bottom surface GS may be configured by combining the patterns A to D in Fig. 3. For example, a pattern may be configured by combining the diagonal lines in Fig. 3A with the checkered pattern in Fig. 3B, or a pattern may be configured by combining both the convex shapes in Fig. 3C with the concave shapes in Fig. 3D. For example, a pattern in which any geometric pattern and a non-geometric pattern are randomly arranged adjacent to each other may be configured.

[0034] The pattern may be a pattern including characters. This allows a distinctive pattern to be provided on each bottom surface of multiple grooves provided in a rubber product. Therefore, by generating three-dimensional data and aligning the three-dimensional data, it becomes possible to provide effective feature points on the bottom surface. For example, the characters may have a pattern in which each of the bottom surfaces GS of the tire has a sequence of different characters. Characters include kanji, katakana, hiragana, English letters, Greek letters, numbers, symbols, etc. The pattern may be configured to include characters in addition to the patterns shown in A to D of Figure 3.

[0035] Any method may be used to design the random pattern. For example, the position of a shape such as a circle on the bottom surface GS may be designed so that the frequency spectrum obtained by performing Fourier analysis in the horizontal and vertical directions is flat. For example, the positions of the shapes such as the circle, letters, etc. may be randomly designed using random numbers according to any probability distribution, such as a normal distribution.

[0036] Each bottom surface GS of the tire may have a different random pattern. For example, the colors of the patterns on each bottom surface GS may be different. In this case, the bottom surface GS is easily extracted as a feature point, particularly in the alignment process of creating three-dimensional data. For example, the shapes, such as circles, that make up the patterns on each bottom surface GS may be different. In this case, the bottom surface GS is easily extracted as a feature point, particularly in the alignment process of creating three-dimensional data.

[0037] 4 to 7, the operation of the measuring device 10 using the rubber product 30 according to this embodiment will be described. The operation described below corresponds to the measuring method according to this embodiment. In this example, the rubber product 30 is a tire.

[0038] In step S1, the control unit 11 acquires three-dimensional data D1 of the tire to be measured. The three-dimensional data is, for example, point cloud data of the tire.

[0039] The control unit 11 may acquire the three-dimensional data D1 by acquiring an image captured by the camera 20, extracting from the image a pattern provided on the bottom surface GS of the tire groove portion G as feature points, and generating the three-dimensional data D1 based on the feature points. The three-dimensional data D1 may be generated using, for example, photogrammetry or the like. The three-dimensional data D1 may also be generated by using an iterative closest point (ICP) algorithm or the like to align point clouds.

[0040] In S2, the control unit 11 measures the wear of the tire. Any method may be used to measure the wear.

[0041] As an example of a wear measurement technique, the control unit 11 may calculate the amount of wear of the tire as a rubber product 30 based on the difference in position between the bottom surface GS of the tire and the surface S before wear. This makes it possible to accurately capture changes in the groove portion due to wear based on three-dimensional data generated based on a pattern provided at the groove bottom. For example, the control unit 11 first calculates the distance between a point on the surface S and a point on the bottom surface GS based on the three-dimensional data D1. The control unit 11 acquires information indicating the distance from a point on the surface S before wear to a point on the bottom surface GS, and calculates the amount of wear by subtracting the calculated distance from the acquired distance. The information indicating the distance from a point on the surface S to a point on the bottom surface GS before wear may be stored in advance in the memory unit 12. The unit of distance may be centimeters, millimeters, etc. The control unit 11 may calculate the volume of the three-dimensional shape of the groove portion G from the surface S to the bottom surface GS, and calculate the amount of wear as the difference between the volume and a predetermined value. The predetermined value is the volume of the groove portion G before wear, and may be stored in the memory unit 12.

[0042] As an example of a wear measurement technique, the control unit 11 may further acquire three-dimensional data D2 of a new rubber product 30, align the three-dimensional data D2 with the three-dimensional data D1 of the worn rubber product 30 acquired in S1 based on the pattern, and, after alignment, calculate the difference between the position of the surface S of the three-dimensional data D2 and the position of the bottom surface GS of the three-dimensional data D1 as the amount of wear. This allows the three-dimensional data to be compared based on the pattern provided on the groove bottom, making it possible to accurately calculate the difference between the surface of the new rubber product and the surface of the worn rubber product. As a result of the comparison, it is possible to easily determine that the greater the difference, the greater the degree of wear. The control unit 11 may acquire the three-dimensional data D2 of a new tire by reading it out from the memory unit 12 in advance. Referring to FIG. 5 , E shows an example of three-dimensional data D1 of the groove portion G of the tire to be measured, and F shows an example of three-dimensional data D2 of the groove portion G of the new tire. In each of the three-dimensional data D1 and D2, a circular pattern indicated by black circles and a diagonal line pattern indicated by straight lines are provided on the bottom surface GS. Comparing the three-dimensional data D1 and D2, it can be seen that the surface S of the worn tire indicated by E has more irregularities due to wear than the surface S of a new tire before wear indicated by F. On the other hand, the pattern of the bottom surface GS does not change between a new tire and a worn tire, and therefore can be seen to be easily extracted as a feature point.

[0043] 6 shows an example of three-dimensional data resulting from superimposing the three-dimensional data D1 shown by E in FIG. 5 and the three-dimensional data D2 shown by F. It can be seen that accurate alignment is achieved by extracting the pattern of the bottom surface GS as a feature point and using this pattern as a reference.

[0044] In S3, the control unit 11 generates a wear map showing the measured wear in three dimensions. This makes it possible to intuitively grasp the degree of wear using a wear map based on three-dimensional data. Any method may be used to generate the wear map. For example, the control unit 11 may generate a three-dimensional model of the tire to be measured from three-dimensional data D1 of the tire, and then generate a wear map in which areas of the surface S in the generated three-dimensional model where the degree of wear is high are colored with a predetermined color based on the wear measurement results in S2. The three-dimensional model in this example is a model in which a planar shape is assigned based on the point cloud. FIG. 7 shows an example of a wear map generated by the control unit 11. In FIG. 7, surfaces S that are colored to indicate particularly high degrees of wear are also indicated by star-shaped symbols. The control unit 11 may color the degree of wear in stages according to threshold values. For example, while FIG. 7 shows that the degree of wear is high at all positions on the surface S, a wear map may be generated in which areas where the degree of wear is below a predetermined value are not colored.

[0045] In S4, the control unit 11 outputs the results of the wear measurement in S2 and the wear map generated in S3 via the input / output unit 14. The control unit 11 may also output the three-dimensional data D1 and the three-dimensional data D2. The control unit 11 may further process the wear map to generate and output a wear profile that represents the outline of a cross section of the tire in the circumferential direction. Thereafter, the processing operation of the control unit 11 ends.

[0046] <Program> A computer capable of executing program instructions can be used to function as the above-described measurement device 10. Here, the computer may be a general-purpose computer, a dedicated computer, a workstation, a personal computer (PC), an electronic notepad, etc. The program instructions may be program code, code segments, etc. for performing the necessary tasks.

[0047] The computer includes a processor, a storage unit, an input unit, an output unit, and a communication unit. The processor may be a CPU, an MPU, a GPU, a DSP (Digital Signal Processor), a SoC (System on a Chip), or the like, and may be configured with multiple processors of the same or different types. The processor controls the above components and performs various arithmetic processing by reading and executing a program from the storage unit. Note that at least a portion of these processing contents may be implemented by hardware. The input unit is an input interface that accepts user input operations and acquires information based on the user operations, such as a pointing device, keyboard, or microphone. The output unit is an output interface that outputs information, such as a display or speaker. The communication unit is a communication interface for communicating with external devices, such as a LAN interface.

[0048] The program may be recorded on a computer-readable recording medium. Using such a recording medium, the program can be installed on a computer. Here, the recording medium on which the program is recorded may be a non-transitory recording medium. The non-transitory recording medium is not particularly limited, and may be, for example, a CD-ROM, a DVD-ROM, or a USB (Universal Serial Bus) memory. Furthermore, the program may be downloaded from an external device via a network.

[0049] Although the above-described embodiments have been described as typical examples, it will be apparent to those skilled in the art that many modifications and substitutions are possible within the spirit and scope of the present disclosure. Therefore, the present disclosure should not be interpreted as being limited by the above-described embodiments, and various modifications and alterations are possible without departing from the scope of the claims. For example, multiple building blocks shown in the block diagrams of the embodiments may be integrated, or a single building block may be divided. Furthermore, multiple steps shown in the flowcharts of the embodiments may be integrated into one, or a single step may be divided. Contributing to the United Nations-led Sustainable Development Goals (SDGs)

[0050] The SDGs have been proposed to realize a sustainable society. One embodiment of the present invention is thought to be a technology that can contribute to goals such as "No. 9 - Build infrastructure for industry and technological innovation," "No. 12 - Responsible consumption and production," and "No. 13 - Take concrete action against climate change."

[0051] REFERENCE SIGNS LIST 1 Measurement system 10 Measurement device 11 Control unit 12 Storage unit 13 Communication unit 14 Input / output unit 20 Camera 30 Rubber product 40 Network

Claims

1. A rubber product having a groove provided on a surface of the rubber, and a pattern for three-dimensional measurement provided on the bottom surface of the groove.

2. The rubber article of claim 1, wherein said pattern is a random pattern.

3. A rubber product according to claim 1 or 2, wherein the pattern is a three-dimensional pattern.

4. A rubber product according to claim 1 or 2, wherein the pattern includes letters.

5. A rubber product according to claim 1 or 2, wherein the rubber is a tire or a crawler.

6. A computer-implemented method for measuring a rubber product, the rubber product having a groove portion provided on a surface of the rubber and a pattern for three-dimensional measurement provided on a bottom surface of the groove, the method including measuring the wear of the rubber product based on the three-dimensional data of the rubber product.

7. The measurement method according to claim 6, further comprising: calculating an amount of wear of the rubber product based on a difference in position between the bottom surface and the surface before wear.

8. A measuring method according to claim 7, comprising: aligning the three-dimensional data of the new rubber product with the three-dimensional data of the worn rubber product based on the pattern; and calculating the difference after the alignment to measure the wear.

9. A method according to claim 6 or 7, further comprising generating a wear map showing the measured wear in three dimensions.

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