A Tire Vulcanization Bladder Uniformity Detection Device and Detection Method

Abstract

The present invention relates to the technical field of tire vulcanization bladder production, and specifically to a device and method for detecting the uniformity of a tire vulcanization bladder. It includes: a rotating platform, an imaging component, a sensor, a control unit, a storage unit, a processing unit, and a display unit. The beneficial effects of the present invention: The uniformity of the tire vulcanization bladder is detected through image recognition technology. Compared with the prior art, the technical solution provided by this application can simultaneously detect the uniformity of the bladder sidewall, shoulder, and crown surface. In addition, the detection device provided by this application can adapt to different models of tire vulcanization bladders for detection, with high detection efficiency and reduced detection costs at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of tire vulcanization bladder production, and specifically to a tire vulcanization bladder uniformity detection device and a detection method. Background Art

[0002] A tire vulcanization bladder is a hollow capsule made of high-temperature resistant rubber. As the core pressure transmission medium in the tire vulcanization process, it applies a uniform hot pressing effect on the tire blank by inflating and expanding, enabling the rubber molecular chains to complete the cross-linking reaction and shape the tire structure. During the vulcanization process, the bladder needs to withstand cyclic loads of high temperatures of 160 - 200 °C and internal pressures of 0.8 - 2.5 MPa, and its performance directly affects the uniformity, mechanical strength, and service life of the finished tire.

[0003] The main reasons for the non-uniformity of tire vulcanization bladders are due to defects in materials and process links. In terms of materials, it is mainly due to improper design of the mold runner or pressure control during injection molding, resulting in wall thickness differences, and uneven dispersion of carbon black in the mixed rubber, causing differences in elastic modulus distribution. In terms of processes, it mainly includes vulcanization process defects and molding die defects. Among them, vulcanization process defects are caused by uneven mold heating or insufficient vulcanization time, resulting in cross-link density gradients, and too fast cooling rate leading to the accumulation of residual stress; molding die defects are caused by the wear of the die cavity and large errors in the sizing process parameters after repeated use of the die, resulting in the geometric shape of the bladder deviating from the design value.

[0004] Since tire vulcanization bladders need to be used cyclically in a high-temperature and high-pressure environment, if the inflated bladders are non-uniform, it will lead to a decline in tire quality. For example, differences in the contact area between the vulcanization bladder and the tire liner cause an increase in local thermal resistance, resulting in synchronous defects of under-vulcanization on the tire sidewall and over-vulcanization on the tire crown; the deformed areas caused by non-uniformity form "low-pressure blind spots", increasing the risk of delamination and bulging; uneven vulcanization pressure causes the radial force variation (RFV) of the tire to exceed the standard, leading to an increase in the unqualified rate of tire dynamic balance, etc.

[0005] In addition, the service life of vulcanization bladders is generally about 500 times. In the production environment, when high-temperature and high-pressure gas is introduced into the tire vulcanization bladder, if its expansion is non-uniform, it will cause the circumferential stress peak value in the locally over-expanded area to exceed the material fatigue limit, resulting in a reduction in the service life of the bladder, increasing the replacement frequency of the vulcanization bladder and reducing production efficiency. Extreme deformation may cause the bladder to burst, leading to production interruption and safety risks.

[0006] Currently, the industry generally adopts a method of combining static geometric dimension measurement with visual inspection, such as using a caliper to measure the wall thickness of key parts and manually observing surface defects, etc. This method cannot effectively detect the deformation characteristics of the bladder in the dynamic working state, and lacks quantitative evaluation means for key parameters such as internal stress distribution and heat conduction uniformity in materials, resulting in potential uniformity defects being difficult to detect in a timely manner. Summary of the invention

[0007] The object of the present invention is to provide a tire curing bladder uniformity detection device and detection method to solve the problems raised in the above background technology.

[0008] A tire curing bladder uniformity detection device, comprising:

[0009] A rotating platform is used to install the tire curing bladder, inflate the curing bladder and drive it to rotate;

[0010] An imaging component, mounted on one side of the rotating platform, for taking photos of the curing bladder;

[0011] A sensor, mounted on one side of the rotating platform, for testing the diameter of the tire curing bladder after inflation;

[0012] A control unit, used to control the rotation rhythm of the rotating platform and the photographing rhythm of the imaging component;

[0013] A storage unit, used for storing images captured by the imaging component;

[0014] A processing unit, used for analyzing and processing the images in the storage unit to identify abnormal images;

[0015] The display unit is used to display the processing result of the processing unit.

[0016] As a further embodiment of the present invention, the rotating platform includes: a clamp for mounting a tire curing bladder, the clamp is provided with an inflation port for inflating the tire curing bladder, and a rotation source for driving the clamp and the tire curing bladder to rotate, and the clamp and the rotation source are transmitted via a rotating shaft.

[0017] As a further embodiment of the present invention, there are multiple imaging components, and the multiple imaging components are respectively arranged on the side surface, shoulder and crown surface of the tire curing bladder.

[0018] As a further embodiment of the present invention, the imaging assembly includes a camera and an optical mirror, the optical mirror is used to reflect the surface pattern of the tire curing bladder, and the camera is used to take a picture of the optical mirror.

[0019] As a further embodiment of the present invention, the optical mirror surface is provided with an imaging area and a background area, the imaging area is surrounded by the background area, the imaging area is provided with a reflective coating, and the background area is provided with a light-shielding coating.

[0020] As a further embodiment of the present invention, the imaging area is a rectangular area.

[0021] The present invention also provides a method for detecting the uniformity of a tire vulcanization bladder, which uses the above-mentioned tire vulcanization bladder uniformity detection device. The steps include:

[0022] Step S1: Install the tire vulcanization bladder on the rotating platform, inflate the tire vulcanization bladder to be measured with gas at a standard pressure, and mark the starting position of the tire vulcanization bladder.

[0023] Step S2: Initialize the system. The control unit obtains the diameter D of the inflated tire vulcanization bladder through the sensor, obtains the arc length L of the camera's horizontal field of view, obtains the imaging overlap rate F, and calculates the total number of camera frames N according to the diameter D, arc length L, and overlap rate F.

[0024] Step S3: Start the rotating platform. The control unit obtains the feedback rotation angle in real time through the encoder. When the rotation angle of the rotating platform reaches 2π / N, the control unit sends a pulse signal to trigger the camera to take a picture, and stores the obtained image matrix P ij in the storage unit, where the subscript i is the camera number and the subscript j is the frame number.

[0025] Step S4: The processing unit performs image analysis on the images in the image matrix P ij to obtain the density matrix T ij corresponding to the images;

[0026] Step S5: The processing unit performs anomaly analysis on the density matrix T ij and stores the analysis result in the matrix Z ij ;

[0027] Step S6: The processing unit makes a data judgment on the matrix Z ij and outputs the result through the display unit.

[0028] As a further embodiment of the present invention, the method for determining the number of frames N is as follows:

[0029] Step S21: The control unit calculates the diameter D of the tire vulcanization bladder according to the position of the sensor and the detected distance, and calculates the circumference C of the tire vulcanization bladder according to the diameter D of the tire vulcanization bladder.

[0030] Step S22: The control unit obtains the arc length L of the camera's horizontal field of view and the imaging overlap rate F input by the user, and calculates the adjacent image interval ΔL according to the arc length L of the camera's horizontal field of view and the imaging overlap rate F, ΔL = L×(1 - F).

[0031] Step S23: The control unit calculates the total number of frames N to be taken according to the circumference C and the adjacent image interval ΔL,

[0032] N = C / ΔL.

[0033] As a further embodiment of the present invention, the steps of the image analysis are as follows:

[0034] Step S41, the processing unit obtains image data from the storage unit, and sequentially extracts images from the image matrix P ij for analysis;

[0035] Step S42, for the color target of the coating in the background area of the image, background segmentation is performed on the extracted image;

[0036] Step S43, sequentially perform grayscale conversion, denoising, and contrast enhancement processing on the segmented image;

[0037] Step S44, count the number of targets, and store the statistical value in the density matrix T ij and store it in the storage unit.

[0038] As a further embodiment of the present invention, the anomaly analysis includes the following steps:

[0039] Step S51, the processing unit obtains the image matrix T ij from the storage unit, and sequentially extracts the entire row data T ij from T i for analysis, T i ={T i1 ,T i2 ,···,T iN};

[0040] Step S52, calculate the median M of the data T i , M = Median(T i );

[0041] Step S53, calculate the absolute deviation d i of each data point from the median, d i =∣T ij −M∣;

[0042] Step S54, calculate the median absolute deviation MAD, MAD = Median({d1, d2, ···, d N});

[0043] Step S55, calculate the modified Z-score Z ij , save the entire row of Z-scores as an array Z i , where:

[0044] Z ij =0.6745·(T ij −M) / MAD;

[0045] Z i ={Z i1 ,Zi2 , ···, Z iN}。

[0046] As a further embodiment of the present invention, the steps of data judgment are as follows:

[0047] Step S61, the processing unit sequentially and circularly performs abnormality determination on Z according to the threshold set by the user ij for abnormality determination;

[0048] Step S62, determine whether there is a Z ij greater than the set threshold. If not, execute step S66. If so, execute step S63;

[0049] Step S63, determine that the product is unqualified, and determine the abnormal position according to the subscript of the abnormal value Z ij ;

[0050] Step S64, obtain the row position according to the first subscript i of Z ij ;

[0051] Step S65, obtain the column position according to the second subscript j of Z ij ;

[0052] Step S66, determine that the product is qualified.

[0053] As a further embodiment of the present invention, it further includes a display result, which is output by the display unit, and the display result includes:

[0054] Number, used to display the number of the vulcanization capsule of the tire to be tested,

[0055] Threshold, the set threshold input by the user,

[0056] Current value, used to display the corrected Z-score at the position specified by the user;

[0057] Detection result, used to display whether the vulcanization capsule of the tire to be tested is qualified;

[0058] Graphical display interface, used to display the test results of the unfolded surface of the vulcanization capsule of the tire to be tested;

[0059] Row subscript, used to display the row coordinate value at the position specified by the user;

[0060] Column subscript, used to display the column coordinate value at the position specified by the user.

[0061] Compared with the prior art, the beneficial effects of the present invention:

[0062] 1. Since the side walls, shoulders, and crown surfaces of a tire vulcanization bladder expand differently after inflation, existing tire vulcanization bladder detection devices can only perform uniformity detection on the crown surface of the bladder. However, the technical solution provided in this application can simultaneously detect the uniformity of the side walls, shoulders, and crown surface of the bladder.

[0063] 2. Existing uniformity detection devices need to design detection devices with different specifications for different models of vulcanization bladders. The detection device provided in this application can adapt to different models of tire vulcanization bladders for detection, with high detection efficiency and reduced detection costs at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 is a schematic structural view of a tire vulcanization bladder;

[0065] Figure 2 is Figure 1 a partial view of the surface of the tire vulcanization bladder in ;

[0066] Figure 3 is a structural view of a tire vulcanization bladder uniformity detection device according to the present invention;

[0067] Figure 4 is Figure 3 a front elevation sectional view in ;

[0068] Figure 5 is a front view of an optical mirror;

[0069] Figure 6 is a flowchart of a method for detecting the uniformity of a tire vulcanization bladder according to the present invention;

[0070] Figure 7 is Figure 6 the method flow for determining the total number of photographed frames in ;

[0071] Figure 8 is Figure 6 the method flow of step S4 in ;

[0072] Figure 9 is Figure 6 the method flow of step S5 in ;

[0073] Figure 10 is the method flow for data judgment;

[0074] Figure 11 is the result output display interface;

[0075] The meanings of the various reference numerals in the figures are as follows:

[0076] Tire curing bladder 1, surface pattern 11, imaging assembly 2, camera 21, optical mirror 22, imaging area 221, background area 222, rotating platform 3, fixture 31, rotating source 32, rotating shaft 33, sensor 4, display result 5, number 51, threshold 52, current value 53, detection result 54, graphical display interface 55, row subscript 56, column subscript 57. Detailed implementation mode

[0077] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0078] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0079] As Figure 1 shown, the shape of the tire curing bladder 1 is a cylindrical structure. When in use, the beads at both ends need to be brought closer to the center. The protruding part in the middle extends into the green tire, and high-temperature and high-pressure steam is introduced, so that it generates a certain pressure on the inner wall of the green tire during the tire curing process. Therefore, the uniformity of the tire curing bladder after inflation is crucial for tire production, and its over-expansion and under-expansion will both affect the curing quality of the tire.

[0080] In existing production, the uniformity of the tire curing bladder is generally detected by visual inspection, and it is difficult to detect minor defects by visual inspection. Generally, only a few uniformity detection devices are used to detect only the crown surface of the tire curing bladder, and less detection is carried out on the side and shoulder of the bladder. The reason is that compared with the crown surface, the stress on the side and shoulder is more complex, the expansion degree is completely different from that of the crown surface, and for different models of the bladder, the position and size after expansion are also different, which requires a very high adaptability of the detection device.

[0081] As Figure 3 、 Figure 4 shown, a tire curing bladder uniformity detection device includes:

[0082] The rotating platform 3 is used to install the tire curing bladder, inflate the curing bladder and drive it to rotate. As a specific embodiment, the rotating platform 3 includes: a clamp 31, which is used to install the tire curing bladder, and the clamp 31 is provided with an inflation port for inflating the tire curing bladder, and a rotation source 32, which is used to drive the clamp 31 and the tire curing bladder to rotate, and the clamp 31 and the rotation source 32 are transmitted through a rotating shaft 33.

[0083] The imaging component 2 is mainly used to take pictures of the pattern on the surface of the tire curing bladder. The main function of the tire curing bladder pattern is to facilitate vulcanization demoulding. Its characteristic is that the pattern of the same shape is evenly distributed on the surface of the curing bladder, such as Figure 2 As shown, the tire pattern in the illustration is a hexagonal pattern, but it can also be a circular or other type of pattern in practice. Since the pattern on the surface of the vulcanizing bladder is evenly distributed, when the vulcanizing bladder is inflated, if it expands evenly, the pattern on its surface is also evenly distributed.

[0084] However, since the expansion coefficients of the side, shoulder and crown of the vulcanized bladder are different after inflation, the pattern density distribution of the side, shoulder and crown of the bladder after inflation is different. Figure 3 As shown, a plurality of imaging components 2 are provided on the cross section of one side of the tire curing bladder. Specifically, the plurality of imaging components 2 are arranged along the longitude of the tire curing bladder and installed on one side of the rotating platform, and are respectively used to take pictures of the patterns on the side, shoulder and crown of the tire curing bladder.

[0085] In a specific embodiment, the tire curing bladder rotates under the drive of the rotating platform 3. Every time the bladder rotates a certain angle, the control unit triggers the camera 21 to take pictures. When the bladder rotates one circle, the images taken by all cameras 21 can form an expanded view of the surface of the tire curing bladder. All the captured images are saved in the form of a picture matrix to the storage unit for processing by the processing unit. Among them, the images taken by a camera 21 around the bladder form a row, and when the rotating platform 3 rotates to a certain angle, the images taken by all cameras form a column. Therefore, when all images are saved as a matrix P ij When , the first subscript i is the row coordinate, representing the position of the camera, and the second subscript j is the column coordinate, representing the rotation angle of the capsule.

[0086] The imaging assembly 2 includes a camera 21 and an optical mirror 22. The optical mirror 22 has an imaging area 221 and a background area 222. The imaging area 221 is surrounded by the background area 222. The imaging area 221 is provided with a reflective coating, and the background area 222 is provided with a light-shielding coating. In a specific embodiment, the imaging area 221 is a rectangular area, such as Figure 5 The imaging area 221 of the optical mirror 22 is used to reflect the surface pattern of the tire curing bladder, and the camera 21 takes a picture of the pattern on the bladder surface by reflecting the optical mirror 22 .

[0087] Specifically, the purpose of setting the imaging area 221 is to facilitate the statistical determination of the number of patterns within a certain area. In the optical lens 22 corresponding to one camera 21, the shape and area of the imaging area 221 remain unchanged. When the tire vulcanization bladder expands uniformly and the tire rotates one week, the number of patterns within the imaging area 221 obtained by the same camera 21 is basically the same. When a local bulge appears on the bladder, the pattern density decreases and the number of patterns within the imaging area 221 decreases. When a local depression appears on the bladder, the pattern density increases and the number of patterns within the imaging area 221 increases during shooting.

[0088] Specifically, the purpose of setting the background area 222 is to facilitate the processing unit to separate the imaging area 221 from the image during image processing. Therefore, the background area 222 should be set to a color with a large contrast to the surface of the bladder, and green can be selected as the color of the background area 222.

[0089] The present invention provides a method for detecting the uniformity of a tire vulcanization bladder, which uses the above-mentioned tire vulcanization bladder uniformity detection device, and the steps include:

[0090] Step S1: Install the tire vulcanization bladder on the rotating platform, inflate the measured tire vulcanization bladder with gas at a standard pressure, and mark the starting position of the tire vulcanization bladder.

[0091] Step S2: Initialize the system. The control unit obtains the diameter D of the inflated tire vulcanization bladder through the sensor, obtains the arc length L of the horizontal field of view of the camera, obtains the imaging overlap rate F, and calculates the total number of camera shooting frames N according to the diameter D, the arc length L, and the overlap rate F.

[0092] Step S3: Start the rotating platform. The control unit obtains the feedback rotation angle in real time through the encoder. When the rotation angle of the rotating platform reaches 2π / N, the control unit sends a pulse signal to trigger the camera to take a picture, and stores the obtained image matrix P ij into the storage unit, where the subscript i is the camera number and the subscript j is the frame number. In a specific embodiment, as Figure 3 shown, from top to bottom along one side section of the tire vulcanization bladder, the camera numbers are camera No. 1, camera No. 2,... According to the rotation direction of the tire vulcanization bladder, the value range of j is 0 - N.

[0093] Step S4: The processing unit performs image analysis on the images in the image matrix P ij and counts the number of patterns in each image, and saves the counted number into the density matrix T ij corresponding to the image;

[0094] Step S5: The processing unit performs abnormal analysis on the density matrix T ij and stores the analysis result into the matrix Zij in;

[0095] Step S6, the processing unit makes a data judgment on matrix Z ij and outputs the result through the display unit.

[0096] As a further embodiment of the present invention, the method for determining the number of frames N is as follows:

[0097] Step S21, the control unit calculates the diameter D of the tire vulcanization capsule according to the position of the sensor 4 and the detected distance. Specifically, the position of the sensor 4 relative to the center of the tire vulcanization capsule is determined. When the capsule is inflated, due to different capsule models, their radii after inflation are different. By detecting the distance from the sensor 4 to the outer circle of the capsule, subtracting the distance from the sensor 4 to the outer circle of the capsule from the distance of the sensor 4 relative to the center of the tire vulcanization capsule, the radius r of the capsule is obtained, and twice the radius is equal to the diameter D. And according to the diameter D of the tire vulcanization capsule, the circumference C of the tire vulcanization capsule is calculated, C = πD;

[0098] Step S22, the control unit obtains the lateral field of view arc length L of the camera and the imaging overlap rate F input by the user, and calculates the adjacent image interval ΔL according to the lateral field of view arc length L of the camera and the imaging overlap rate F, ΔL = L×(1 - F);

[0099] Step S23, the control unit calculates the total number of frames N to be captured according to the circumference C and the adjacent image interval ΔL,

[0100] N = C / ΔL.

[0101] As a further embodiment of the present invention, image analysis can use professional software, such as OpenCV, etc. to process the images, and the steps are as follows:

[0102] Step S41, the processing unit obtains the image data from the storage unit and sequentially extracts the images from the image matrix P ij for analysis;

[0103] Step S42, for the specific color target of the coating in the background area of the image, the extracted image is subjected to background segmentation, the image in the imaging area is retained, and the image in the background area and outside the background area is removed;

[0104] Step S43, sequentially perform graying processing on the pattern images in the imaging area, convert the RGB image to a grayscale image, then use Gaussian filtering or median filtering to remove noise, and finally enhance the contrast for subsequent statistics. In the processed image, the patterns are highlighted, and the intervals between the patterns appear as dark areas;

[0105] Step S44, use the findContours function in OpenCV to count the number of target patterns and store the statistical value in the density matrix T ijand store T ij in the storage unit.

[0106] Obtain the density matrix T ij After that, analyze the data in T ij to find the abnormal data. Since the subscript i represents different camera numbers, and different cameras correspond to different photographing positions. For example, camera No. 1 corresponds to the side, camera No. 2 corresponds to the shoulder, camera No. 3 corresponds to the crown surface, etc. The inflation conditions of the capsule side, shoulder, and crown surface are completely different. Therefore, comparing the images of different cameras is meaningless. And the same camera takes continuous photos along the latitude line of the capsule, and the inflation coefficient on the same latitude line of the capsule is the same. Therefore, the entire row of data of T ij {T i1 , T i2 , ···, T iN} should be compared.

[0107] In addition, since the pattern densities of tire vulcanization capsules of different models are different, in order to find the abnormal data in the entire row of data {T i1 , T i2 , ···, T iN}, the present invention also provides an abnormal analysis method, and this abnormal analysis includes the following steps:

[0108] Step S51, the processing unit obtains the image matrix T ij from the storage unit, and sequentially extracts the entire row of data T ij from T i for analysis, T i = {T i1 , T i2 , ···, T iN};

[0109] Step S52, calculate the median M of the data T i , M = Median(T i );

[0110] Step S53, calculate the absolute deviation d i of each data point from the median, d i = ∣T ij −M∣;

[0111] Step S54, calculate the median absolute deviation MAD, MAD = Median({d1, d2, ···, d N});

[0112] Step S55, calculate the modified Z-score Z ij , Z ij is used to evaluate the degree to which the data point T ij deviates from the mean value, and then save the entire row of Z-scores as an array Zi , where:

[0113] Z ij = 0.6745·(T ij − M) / MAD;

[0114] Z i = {Z i1 , Z i2 , ···, Z iN};

[0115] The abnormal analysis method provided by the present invention is a flexible abnormal judgment method, which is not affected by factors such as inflation pressure and capsule model, and can dynamically find abnormal data of pattern density according to the pattern density distribution. The detection strictness can also be adjusted according to different requirements.

[0116] Perform data judgment on the obtained corrected Z-score Z ij to identify whether the product under test is qualified. The steps are as follows:

[0117] Step S61, the processing unit sequentially and cyclically performs abnormal determination on Z ij according to the user-set threshold;

[0118] Step S62, determine whether there is a Z ij greater than the set threshold. If not, execute step S66. If so, execute step S63;

[0119] Step S63, determine that the product is unqualified, and determine the abnormal position according to the subscript of the abnormal value Z ij ;

[0120] Step S64, obtain the row position according to the first subscript i of Z ij . The first subscript i represents the camera position and can correspond to find the latitude position of the tire vulcanization capsule;

[0121] Step S65, obtain the column position according to the second subscript j of Z ij . The second subscript j represents the rotation angle of the tire vulcanization capsule and can find the longitude position of the tire vulcanization capsule. Combining with the latitude position in S64, the abnormal position of the capsule can be quickly located;

[0122] Step S66, determine that the product is qualified

[0123] As a further implementation manner of the present invention, a display result 5 is also provided. As Figure 11 shown, the display result 5 is output through the display unit and can visually display the uniformity distribution of the surface of the tire vulcanization capsule. The display result 5 includes:

[0124] Number 51, used to display the number of the tire vulcanization capsule under test,

[0125] Threshold value 52, the set threshold value input by the user

[0126] Current value 53, used to display the corrected Z-score at the position specified by the user

[0127] Detection result 54, used to display whether the vulcanization capsule of the tire under test is qualified

[0128] Graphical display interface 55, used to display the test results of the unfolded surface of the vulcanization capsule of the tire under test, and different test results are displayed in different colors, which can intuitively display the detection results of the entire surface of the vulcanization capsule of the tire

[0129] Row subscript 56, used to display the row coordinate value at the position specified by the user

[0130] Column subscript 57, used to display the column coordinate value at the position specified by the user

[0131] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art of this industry should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A tire curing bladder uniformity detection device, characterized in that: include: A rotating platform (3) is used to install a tire curing bladder, inflate the curing bladder and drive it to rotate; An imaging component (2) is mounted on one side of the rotating platform (3), the imaging component (2) comprising a camera (21) and an optical mirror (22), the optical mirror (22) being used to reflect the surface pattern of the tire curing bladder, and the camera (21) being used to take a picture of the optical mirror (22); A sensor (4) is mounted on one side of the rotating platform (3) and is used to test the diameter of the tire curing bladder after it is inflated; A control unit, used to control the rotation rhythm of the rotating platform (3) and the photo taking rhythm of the imaging component (2); A storage unit, used for storing images captured by the imaging component (2); The processing unit is used to analyze and process the image in the storage unit, count the number of target patterns in the image, save the statistical value in the density matrix, perform statistical analysis on the data in the density matrix, calculate the deviation of each data point from the median of the density matrix, and identify abnormal images according to the deviation; The display unit is used to display the processing result of the processing unit.

2. A tire curing bladder uniformity detection device according to claim 1, characterized in that: The rotating platform (3) comprises: a clamp (31) for mounting a tire vulcanizing bladder, the clamp (31) being provided with an inflation port for inflating the tire vulcanizing bladder, and a rotation source (32) for driving the clamp (31) and the tire vulcanizing bladder to rotate, the clamp (31) and the rotation source (32) being transmitted via a rotating shaft (33).

3. A tire curing bladder uniformity detection device according to claim 2, characterized in that: There are a plurality of imaging components (2), and the plurality of imaging components (2) are respectively arranged on the side surface, shoulder and crown surface of the tire curing bladder.

4. A tire curing bladder uniformity detection device according to claim 3, characterized in that: An imaging area (221) and a background area (222) are provided on the surface of the optical mirror (22); the imaging area (221) is surrounded by the background area (222); the imaging area (221) is provided with a reflective coating, and the background area (222) is provided with a light-shielding coating.

5. A tire curing bladder uniformity detection device according to claim 4, characterized in that: The imaging area (221) is a rectangular area.

6. A method for detecting uniformity of a tire curing bladder, using the tire curing bladder uniformity detection device according to any one of claims 1 to 5, comprising the steps of: Step S1, installing a tire curing bladder on a rotating platform, injecting gas of standard pressure into the tested tire curing bladder, and marking the starting position of the tire curing bladder; Step S2, system initialization, the control unit obtains the diameter D of the inflated tire curing bladder through the sensor, obtains the arc length L of the camera's lateral field of view, obtains the imaging overlap rate F, and calculates the total number of camera frames N according to the diameter D, arc length L and overlap rate F; Step S3, start the rotating platform, and the control unit obtains the feedback rotation angle in real time through the encoder. When the rotation angle of the rotating platform reaches 2π / N, the control unit sends a pulse signal to trigger the camera to take a photo, and the obtained image matrix P ij Stored in the storage unit, where subscript i is the camera number and subscript j is the frame number; Step S4: the processing unit processes the image matrix P ij Perform image analysis on the images in the image, count the number of tire curing bladder surface patterns in each image, and save the counted number to the density matrix T corresponding to the image ij ; Step S5: the processing unit processes the density matrix T ij Perform anomaly analysis and store the analysis results in matrix Z ij middle; Step S6: the processing unit processes the matrix Z ij After data judgment, the result is output through the display unit.

7. A tire curing bladder uniformity detection method according to claim 6, characterized in that: The method for determining the number of frames N is as follows: Step S21, the control unit calculates the diameter D of the tire curing bladder according to the position of the sensor and the detected distance, and calculates the circumference C of the tire curing bladder according to the diameter D of the tire curing bladder; Step S22, the control unit obtains the arc length L of the camera's lateral field of view and the imaging overlap ratio F input by the user, and calculates the adjacent image interval ΔL according to the arc length L of the camera's lateral field of view and the imaging overlap ratio F, ΔL=L×(1-F); Step S23: The control unit calculates the total number of frames N required to be captured based on the perimeter C and the interval ΔL between adjacent images. N=C / ΔL.

8. A tire curing bladder uniformity detection method according to claim 7, characterized in that: The steps of the image analysis are as follows: Step S41: The processing unit obtains image data from the storage unit and obtains image data from the image matrix P ij The images are taken out one by one for analysis; Step S42, performing background segmentation on the extracted image with respect to the color target of the coating in the background area of ​​the image; Step S43, sequentially performing grayscale conversion, denoising and contrast enhancement processing on the segmented image; Step S44, counting the number of targets and storing the statistical values ​​in the density matrix T ij and stores it in the storage unit.

9. A tire curing bladder uniformity detection method according to claim 8, characterized in that: The abnormality analysis comprises the following steps: Step S51: The processing unit obtains the image matrix T from the storage unit. ij , and from T ij Take out the entire row of data T in turn i For analysis, T i ={T i1 ,T i2 ,···,T iN }; Step S52, calculate data T i The median M, M=Median(T i ); Step S53, calculate the absolute deviation d of each data point from the median i , d i =|T ij −M∣; Step S54, calculate the median deviation MAD, MAD=Median({d1,d2,···,d N }) Step S55, calculate the modified Z score Z ij , save the Z scores for the entire row as array Z i ,in: Z ij =0.6745·(T ij −M) / MAD; WITH i ={Z i1 ,WITH i2 ,···,WITH iN }。 10. A tire curing bladder uniformity detection method according to claim 9, characterized in that: The steps of data judgment are as follows: Step S61: The processing unit cycles through Z in sequence according to the threshold value set by the user. ij Make abnormal determination; Step S62, determine whether Z ij If the value is greater than the set threshold, if it does not exist, go to step S66; if it does exist, go to step S63; Step S63: determine that the product is unqualified and ij The subscript of determines the abnormal position; Step S64, according to Z ij The first subscript i gets the row position; Step S65, according to Z ij The second subscript j gets the column position; Step S66, determining whether the product is qualified.

11. A tire curing bladder uniformity detection method according to claim 10, characterized in that: The device also includes a display result (5), wherein the display result (5) is output via the display unit, and the display result (5) includes: Number (51) is used to display the number of the tire curing bladder being tested. Threshold (52), the threshold set by the user, Current value (53), used to display the corrected Z score for the user-specified location; The test result (54) is used to indicate whether the tested tire curing bladder is qualified; A graphic display interface (55) for displaying the test result of the surface development of the tested tire curing bladder; Row subscript (56), used to display the row coordinate value of the user-specified position; Column subscript (57) is used to display the column coordinate value of the user-specified position.

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