Tire curing bladder uniformity detection device and detection method

Abstract

The invention relates to the technical field of tire curing bladder production, in particular to a tire curing bladder uniformity detection device and method. Comprising a rotating platform, an imaging assembly, a sensor, a control part, a storage part, a processing part and a display part. The method has the beneficial effects that the uniformity of the tire curing bladder is detected through the image recognition technology, and compared with the prior art, the technical scheme provided by the invention can detect the uniformity of the side wall, the shoulder and the crown surface of the bladder at the same time. In addition, the detection device provided by the invention can adapt to detection of tire curing bladders of different models, the detection efficiency is high, and the detection cost is reduced at the same time.

Description

Technical Field

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

[0002] Tire curing bladder is a hollow bladder made of high temperature resistant rubber. As the core pressure transmission medium of tire curing process, it applies uniform heat and pressure to the tire embryo through inflation, so that the rubber molecular chain completes the cross-linking reaction and shapes the tire structure. During the curing process, the bladder needs to withstand cyclic loads of 160-200℃ high temperature and 0.8-2.5MPa internal pressure. Its performance directly affects the uniformity, mechanical strength and service life of the finished tire.

[0003] The main causes of uneven tire curing bladders are defects in materials and processes. In terms of materials, it is mainly due to improper mold flow channel design or pressure control during injection molding, which leads to differences in wall thickness, and uneven dispersion of carbon black in the rubber compound, which leads to differences in elastic modulus distribution. In terms of processes, it is mainly caused by defects in the vulcanization process and defects in the molding mold. Among them, defects in the vulcanization process are caused by uneven mold heating or insufficient vulcanization time, which causes a cross-linking density gradient, and excessive cooling rate leads to residual stress accumulation; defects in the molding mold are caused by the wear of the mold cavity and the large errors in the molding process parameters after repeated use, which causes the geometry of the bladder to deviate from the design value.

[0004] Since tire curing bladders need to be recycled under high temperature and high pressure, uneven inflation of the tire curing bladders will lead to deterioration of tire quality. For example, the difference in contact area between the curing bladder and the tire body lining leads to increased local thermal resistance, causing synchronization defects such as under-curing of the sidewall and over-curing of the crown. The uneven deformation area forms a "low-pressure blind area", increasing the risk of delamination and bulging. The uneven curing pressure causes the tire radial force fluctuation (RFV) to exceed the standard, resulting in an increase in the tire dynamic balance failure rate.

[0005] In addition, the service life of the curing bladder is generally about 500 times. In the production environment, when high-temperature and high-pressure gas is introduced into the tire curing bladder, if it expands unevenly, the peak circumferential stress in the local over-expansion area will exceed the material fatigue limit, thereby reducing the service life of the bladder, increasing the replacement frequency of the curing bladder and reducing production efficiency. Extreme deformation may cause the bladder to burst, resulting in production interruption and safety risks.

[0006] At present, the industry generally adopts static geometric dimension measurement combined with visual inspection, such as using calipers to measure the wall thickness of key parts and manually observing surface defects. This method cannot effectively detect the deformation characteristics of the capsule under dynamic working conditions, and lacks quantitative evaluation methods for key parameters such as internal stress distribution and heat conduction uniformity of the material, making it difficult to detect potential uniformity defects 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: A rotating platform is used to install the tire curing bladder, inflate the curing bladder and drive it to rotate; An imaging component, mounted on one side of the rotating platform, for taking photos of the curing bladder; A sensor, mounted on one side of the rotating platform, for testing the diameter of the tire curing bladder after inflation; A control unit, used to control the rotation rhythm of the rotating platform and the photographing rhythm of the imaging component; A storage unit, used for storing images captured by the imaging component; A processing unit, used for analyzing and processing the images in the storage unit to identify abnormal images; The display unit is used to display the processing result of the processing unit.

[0009] 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.

[0010] 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.

[0011] 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.

[0012] 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.

[0013] As a further embodiment of the present invention, the imaging area is a rectangular area.

[0014] The present invention also provides a tire curing bladder uniformity detection method, which uses the tire curing bladder uniformity detection device, and the steps include: 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. 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 image in and obtain 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.

[0015] As a further implementation of the present invention, 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.

[0016] As a further embodiment of the present invention, the steps of 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.

[0017] As a further embodiment of the present invention, 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; Z i ={Z i1 ,Z i2 ,···,Z iN}.

[0018] As a further implementation of the present invention, 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.

[0019] As a further embodiment of the present invention, it further includes a display result, which is output by the display unit and includes: Number, used to display the number of the tire curing bladder being tested. Threshold, the threshold set by the user, The current value is used to display the corrected Z score at the user-specified location; The test result is used to show whether the tested tire curing bladder is qualified; Graphical display interface, used to display the test results of the surface of the tested tire curing bladder; Row subscript, used to display the row coordinate value of the user-specified position; Column subscript, used to display the column coordinate value of the user-specified position.

[0020] Compared with the prior art, the present invention has the following beneficial effects: 1. Since the sidewall, shoulder and crown of the tire curing bladder expand differently after it is inflated, the existing tire curing bladder detection device can only detect the uniformity of the bladder crown, while the technical solution provided in this application can detect the uniformity of the bladder sidewall, shoulder and crown at the same time.

[0021] 2. Existing uniformity detection devices require different specifications of detection devices to be designed for different types of vulcanization bladders. The detection device provided in this application can be adapted to different types of tire vulcanization bladders for detection, with high detection efficiency and reduced detection costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of a tire curing bladder; Figure 2 for Figure 1 Partial view of the surface of the tire curing bladder; Figure 3 This is a structural view of a tire curing bladder uniformity detection device of the present invention; Figure 4 for Figure 3 The front section view in ; Figure 5 is the front view of the optical mirror; Figure 6 A flow chart of a method for detecting uniformity of a tire curing bladder according to the present invention; Figure 7 for Figure 6 Method flow for determining the total number of frames for taking photos; Figure 8 for Figure 6 The method flow of step S4 in FIG. Fig. 9 for Figure 6 The method flow of step S5; Fig.10 Method flow for data judgment; Fig.11 Provides an interface for displaying result output; The meaning of each number in the figure is: Tire curing bladder 1, surface pattern 11, imaging component 2, camera 21, optical mirror 22, imaging area 221, background area 222, rotating platform 3, clamp 31, rotation source 32, rotating shaft 33, sensor 4, display result 5, number 51, threshold value 52, current value 53, detection result 54, graphic display interface 55, row subscript 56, column subscript 57. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0025] like Figure 1 As shown, the tire curing bladder 1 is in the shape of a cylindrical structure. When in use, the sub-openings at both ends need to be brought close to the center, and the protruding part in the middle extends into the green tire, and is injected with high-temperature and high-pressure steam, so that it generates a certain pressure on the inner wall of the green tire during the tire vulcanization process. Therefore, the uniformity of the tire curing bladder after inflation plays a vital role in tire production, and its over-expansion and under-expansion will affect the vulcanization quality of the tire.

[0026] In current production, the uniformity of tire curing bladders is generally tested by visual inspection, which is difficult to detect minor defects. A few uniformity testing equipments are generally only used to test the crown surface of tire curing bladders, and the side and shoulder of the bladder are rarely tested. The reason is that the force on the side and shoulder is more complicated than that on the crown surface, and the expansion degree is completely different from that on the crown surface. In addition, the size of the position after expansion is different for different bladder models, which requires a high adaptability of the testing equipment.

[0027] like Figure 3 , Figure 4 As shown, a tire curing bladder uniformity detection device comprises: 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.

[0028] 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.

[0029] 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.

[0030] 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 ijWhen , 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.

[0031] 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 .

[0032] Specifically, the purpose of setting the imaging area 221 is to facilitate the counting of the number of patterns within the determined area. In the optical lens 22 corresponding to a camera 21, the shape and area of ​​the imaging area 221 remain unchanged. When the tire curing bladder is uniformly expanded, the number of patterns in the imaging area 221 obtained by the same camera 21 when the tire rotates one circle is basically the same. When a bulge appears locally on the bladder, its pattern density decreases, and the number of patterns in the imaging area 221 decreases. When the bladder is partially concave, its pattern density increases, and when shooting, the number of patterns in the imaging area 221 increases.

[0033] 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 with the capsule surface. Green can be selected as the color of the background area 222.

[0034] The present invention provides a tire curing bladder uniformity detection method, which uses the tire curing bladder uniformity detection device, and the steps include: 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. The obtained image matrix P ij The subscript i is the camera number, and the subscript j is the frame number. In a specific embodiment, Figure 3As shown, from top to bottom of the cross section of one side of the tire curing bladder, the camera numbers are camera 1, camera 2, etc. According to the rotation direction of the tire curing bladder, the value range of j is 0-N.

[0035] Step S4: the processing unit processes the image matrix P ij Perform image analysis on the images in the image, count the number of patterns in each image, and save the counted number to the density matrix T corresponding to the image ij middle; 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.

[0036] As a further implementation of the present invention, a 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 4 and the detected distance. Specifically, the position of the sensor 4 relative to the center of the tire curing bladder is determined. When the bladder is inflated, the inflated radius is different due to different bladder models. By detecting the distance between the sensor 4 and the outer circle of the bladder, the radius r of the bladder is obtained by subtracting the distance between the sensor 4 and the outer circle of the bladder from the distance between the sensor 4 and the center of the tire curing bladder. The 2 times radius is equal to the diameter D. The circumference C of the tire curing bladder is calculated according to the diameter D of the tire curing bladder, C=πD. 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.

[0037] As a further embodiment of the present invention, image analysis can use professional software, such as OpenCV, to process the image, and the steps 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, for the specific color target of the coating in the background area of ​​the image, background segmentation is performed on the extracted image, the image in the imaging area is retained, and the background area and the image outside the background area are removed; Step S43, grayscale the pattern images in the imaging area in turn, convert the RGB image into a grayscale image, then use Gaussian filtering or median filtering to remove noise, and finally enhance the contrast for subsequent statistics. The pattern in the processed image is highlighted, and the intervals between the patterns are displayed as dark areas; Step S44, using the findContours function in OpenCV to count the number of target patterns and store the statistical values ​​in the density matrix T ij and T ij Stored in the storage unit.

[0038] Get the density matrix T ij Then we need to ij Analyze the data in and find the abnormal data. Since the subscript i represents different camera numbers, and different cameras correspond to different shooting positions, such as camera 1 corresponds to the side, camera 2 corresponds to the shoulder, camera 3 corresponds to the crown, etc., the expansion of the capsule side, shoulder and crown is completely different, so the comparison between images of different cameras is meaningless. The same camera takes pictures continuously along the latitude of the capsule, and the expansion coefficient of the capsule on the same latitude is the same, so T should be taken. ij The entire row of data {T i1 ,T i2 ,···,T iN} for comparison.

[0039] In addition, since the pattern density of different tire curing bladders is different, in order to find the entire row of data {T i1 ,T i2 ,···,T iN The present invention also provides an abnormality analysis method, which includes 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,···,dN}) Step S55, calculate the modified Z score Z ij , Z ij Used to evaluate data point T ij The degree of deviation from the mean is then stored in the array Z. i ,in: Z ij =0.6745·(T ij −M) / MAD; Z i ={Z i1 ,Z i2 ,···,Z iN}.

[0040] 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 pattern density data according to pattern density distribution. The strictness of the detection can also be adjusted according to different needs.

[0041] Get the modified Z score Z ij Data judgment is performed to identify whether the tested product is qualified. The steps 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 of gets the row position, and the first subscript i represents the camera position, which can be used to find the latitude position of the tire curing bladder; Step S65, according to Z ij The second subscript j of gets the column position. The second subscript j represents the rotation angle of the tire curing bladder. The longitude position of the tire curing bladder can be found. Combined with the latitude position not affected by S64, the abnormal position of the bladder can be quickly located. Step S66: Determine if the product is qualified As a further embodiment of the present invention, a display result 5 is also provided, such as Fig.11 As shown, the display result 5 is outputted through the display unit, which can visually display the uniformity distribution of the tire curing bladder surface. 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, The current value is 53, which is 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 is used to display the test results of the surface of the tested tire curing bladder. Different test results are displayed in different colors, which can intuitively display the test results of the entire tire curing bladder surface. The row subscript 56 is used to display the row coordinate value of the user-specified position; The column subscript 57 is used to display the column coordinate value of the user-specified position.

[0042] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached 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) and is used to take photos of the vulcanization bladder; 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); A processing unit, used for analyzing and processing the images in the storage unit to identify abnormal images; 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: The imaging component (2) comprises a camera (21) and an optical mirror (22); the optical mirror (22) is used to reflect the surface pattern of the tire vulcanization bladder, and the camera (21) is used to take a picture of the optical mirror (22).

5. A tire curing bladder uniformity detection device according to claim 4, 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.

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

7. 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 6, the steps comprising: 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 image in and obtain 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.

8. A tire curing bladder uniformity detection method according to claim 7, 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.

9. A tire curing bladder uniformity detection method according to claim 8, 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.

10. A tire curing bladder uniformity detection method according to claim 9, 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 }。 11. A tire curing bladder uniformity detection method according to claim 10, 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.

12. A tire curing bladder uniformity detection method according to claim 11, 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.

Images