Tire inner wall film thickness non-contact detection sensor, method and system

Abstract

The invention belongs to the field of finished product quality detection of all-steel or engineering tires, and particularly relates to a tire inner wall film thickness non-contact detection sensor, method and system, an electromagnetic sensor and a laser displacement sensor are integrally arranged on a shell, and the tire inner wall thickness is measured in a non-contact mode. The measuring channel is arranged in the center of the electromagnetic sensor in the axial direction, the laser sensor is used for measuring the lining rubber layer of the tire through the measuring channel, the electromagnetic sensor is used for measuring the net-shaped metal layer of the tire, and on the premise that the measuring range and the measuring precision of the electromagnetic sensor and the laser displacement sensor are met, the measuring accuracy is improved. The size of the electromagnetic sensor and the size of the laser displacement sensor can be reduced at the same time, the diameter of the fused sensor is smaller than 40 mm, the height of the fused sensor is smaller than 80 mm, and the detection sensor can rotate in the tire to measure the inner walls of different positions of the tread, the tire wall and the tire shoulder of the tire so as to be suitable for the use environment with the small internal space of the tire.

Description

Technical Field

[0001] The present invention belongs to the field of finished product quality inspection of all-steel or engineering tires, and in particular relates to a non-contact detection sensor, method and system for the thickness of a film on the inner wall of a tire. Background Art

[0002] The inner tire film, also known as the inner liner, is a crucial component of tire design. Its thickness directly impacts the tire's puncture resistance, durability, and safety. In particular, to reduce material costs, tire factories now pre-vulcanize the film, resulting in thinner inner liner films. During production, this inevitably causes the inner tire wall, especially the shoulder, to fall below the minimum thickness limit, posing a significant safety hazard. Normally, exposed steel wire is visible to the human eye; otherwise, it cannot be detected manually or measured using data. Tire defects pose a significant safety hazard to vehicles.

[0003] At present, the traditional thickness detection of the inner liner layer of the inner wall of the tire is mainly done by experienced workers who check for exposed steel wires with their eyes and touch to see if there are any steel wires that are about to be exposed. Factories that attach great importance to quality purchase offline measuring instruments. Manual handheld depth detector sensors are used to perform contact measurement on parts that are prone to thin thickness during the production process. Multiple points such as the shoulder, sidewall, and groin are selected for measurement. Local compliance means that the tire is qualified as a whole. Branded tire manufacturers can only increase personnel and instruments for full inspection, which increases production costs and leads to a decrease in production efficiency. In order to ensure data traceability, the tire's barcode is scanned and recorded at the same time, corresponding to the measurement data. If a problem occurs, the production process can be traced. These processes are completely dependent on the operator's experience and sense of responsibility. In addition, offline detection is inefficient and cannot achieve full-scale thickness detection of every produced tire.

[0004] With the increasing requirements for tire safety performance and the rapid development of sensing technology and AI, full inspection of tire inner wall film thickness defects is an inevitable trend. However, the current offline technology method of contacting the sensor to the measurement position cannot be used for online detection. Therefore, developing a sensor and system that does not affect the efficiency of tire online detection and can realize online detection of tire inner wall thickness defects is of universal importance to improving tire production efficiency and ensuring product quality.

[0005] PCT application WO2010 / 104466A1 discloses a method and apparatus for contactlessly measuring the thickness of a non-metallic coating on a metal substrate. The apparatus uses a magnetoresistive sensor to measure the distance to the plate, minus the distance to the paint surface measured by a confocal sensor, to determine the paint thickness. However, the apparatus's detection accuracy only allows for thickness variations within a ±5μm range, while tire inner wall thickness varies between 0 and 6mm. This approach cannot meet the required range of tire inner wall thickness variations. Furthermore, measuring the tire inner wall requires inserting the sensor into the tire and performing measurements at varying angles. Given the confocal sensor's 6mm measurement range, the lens assembly structure within the confocal sensor limits the required working space to over 150mm. The combined length, working distance, and cable bend radius of the confocal sensor, combined with the cable's bending radius, results in a working space exceeding 150mm. For example, the sprocket of an all-steel radial tire is 105mm. Therefore, the confocal sensor cannot penetrate the tire's sprocket completely, let alone accurately measure the tire by rotating the device within the tire.

[0006] Japanese patent JPH08304009A discloses a device and method for measuring the thickness of rubber on the tire surface. The device uses an eddy current sensor to measure the thickness of the rubber on the tire's outer surface by moving a cylinder to bring the sensor into contact with the tire's outer wall. However, the device is too large and the space inside the tire is small, making it impossible to use the device as a whole to penetrate deep into the tire to measure the thickness of the tire's inner wall. Summary of the Invention

[0007] The main purpose of the present invention is to provide a non-contact detection sensor, method and system for the thickness of the inner wall film of the tire, so as to solve the problem in the prior art that the thickness defect of the inner wall film liner of the tire cannot be detected due to the narrow space inside the tire or the detection efficiency is low and the accuracy is insufficient, thereby reducing the dependence on manual labor, reducing the detection cost, improving the detection efficiency and realizing the full inspection of the tire.

[0008] The technical problem to be solved by the present invention is achieved by adopting the following technical solution: A non-contact detection sensor for the thickness of the film on the inner wall of a tire comprises a housing, an electromagnetic sensor and a laser sensor, wherein the housing is made of a non-metallic material; A measuring channel is provided in the center of the electromagnetic sensor along the axial direction; The laser sensor and the electromagnetic sensor are integrated on the housing, and the laser sensor is located on the opposite side of the measuring end face of the electromagnetic sensor; The laser sensor performs measurement through a measurement channel.

[0009] Preferably, the laser sensor includes a transmitting lens and a receiving lens, and a reflector is provided in the measuring channel; The transmitting lens is used to transmit laser light along the axial direction of the measuring channel; The receiving lens is used to receive the light beam reflected back by the reflector. In order to reduce the overall size of the sensor, it is necessary to reduce the size of the laser sensor and the size of the electromagnetic sensor at the same time. Among them, in order to reduce the outer diameter of the electromagnetic sensor, the size of the measurement channel is usually smaller, and in order to further reduce the size of the laser sensor, the distance between the transmitting lens and the receiving lens of the laser sensor will be closer. However, due to the limitations of the internal measurement space of the tire and the measurement range of the sensor, the measuring end face of the laser sensor cannot be far away from the inner wall of the tire. Although the laser emitted by the transmitting lens can pass through the measurement channel, the light beam reflected back by the laser emitted by the laser sensor is difficult to be transmitted to the receiving lens through the measurement channel. The present invention realizes the reception of the light beam by the receiving lens through the reflection of the light path by arranging a reflector in the measurement channel, and achieves the purpose of reducing the size of the laser sensor while meeting the measurement range.

[0010] Preferably, the present invention further comprises a mounting bracket, wherein the mounting bracket is made of a non-metallic material, and the reflector is mounted on the mounting bracket; The mounting bracket is detachably mounted within the measurement channel. The reflector is first mounted on the mounting bracket, and then the mounting bracket is installed within the measurement channel. This allows for precise installation of the reflector and overcomes the challenge of a small measurement channel. The mounting bracket is made of a non-metallic material, which prevents interference with the electromagnetic sensor's magnetic field, ensuring the sensor's measurement accuracy and stability.

[0011] Preferably, the mounting bracket is interference-fitted or adhered to the measuring channel. Interference-fitting or adhering the mounting bracket made of non-metallic material to the measuring channel can prevent metal material from entering the measuring channel and interfering with the magnetic field of the electromagnetic sensor.

[0012] In the present invention, preferably, there is more than one reflector. When the thickness of the electromagnetic sensor is small, the measuring channel is short, and a single reflector can be used to reflect and transmit the light beam reflected by the object to be measured to the receiving lens.

[0013] When the electromagnetic sensor is thick, the measurement channel is long, and a single reflection alone is not enough to transmit the light beam reflected from the object to the receiving lens. Therefore, by installing two or more reflectors, the light beam reflected from the object is reflected multiple times before being transmitted to the receiving lens. The received light reflected by the laser is reflected multiple times between multiple optical reflectors, extending the optical path and reducing the physical size of the receiving system. At the same time, a longer optical path is achieved in a smaller space, maintaining the focal length and angular resolution of the receiving system, and ensuring detection accuracy within the laser sensor's detection range.

[0014] Preferably, the sum of the reflection path lengths of the light beams received by the receiving lens is equal to the reflection path length of the laser light emitted by the laser sensor in the laser triangulation method. To reduce the size of the laser sensor, the present invention reduces the distance between the transmitting lens and the receiving lens. The laser sensor of the present invention utilizes triangulation for distance measurement. To meet the requirements of the light transmission path, the present invention utilizes a reflector to reflect the laser beam reflected by the object to be measured, so that the sum of the reflection path lengths of the light beams received by the receiving lens is equal to the reflection path length of the laser light emitted by the laser sensor in the laser triangulation method.

[0015] The present invention also discloses a non-contact detection method for the thickness of a film on the inner wall of a tire. The method uses the above-mentioned non-contact detection sensor for the thickness of a film on the inner wall of a tire. The sensor is inserted into the interior of the tire. The position and angle of the sensor are adjusted so that the axis of the measurement channel is perpendicular to the inner wall of the tire, and the positions to be measured are all within the measurement range of the electromagnetic sensor and the laser sensor. Taking the measuring end face of the electromagnetic sensor as the reference end face, the electromagnetic sensor is used to measure the distance from the reference end face to the surface of the mesh metal layer of the tire; The fixed distance between the measuring end face of the electromagnetic sensor and the measuring end face of the laser sensor is known. By measuring the distance from the end face to the inner liner rubber surface of the tire, the distance yc' from the reference end face to the inner liner rubber surface of the tire is obtained. The thickness from the inner liner rubber surface to the mesh metal layer surface is y0 = ye - yc'. Since electromagnetic sensors and laser sensors have measurement range requirements, and the laser sensor's measurement range is smaller than that of the electromagnetic sensor due to structural reasons, the position and angle of the non-contact tire inner wall film thickness detection sensor must be adjusted inside the tire so that the axis of the measurement channel is perpendicular to the tire inner wall and the distance from the electromagnetic sensor and laser sensor to the tire inner wall are within their respective measurement ranges to achieve effective measurement. To ensure that the entire sensor is located inside the tire and can rotate nearly 360 degrees, the overall sensor diameter is typically less than 40mm and the length is less than 80mm. Correspondingly, the electromagnetic sensor's detection range is within 11mm, and the laser sensor's detection range is within 6mm.

[0016] Preferably, the present invention uses a sample with a standard thickness of y0c from the surface of the inner lining rubber layer to the surface of the mesh metal layer to calibrate the thickness value y0, specifically: After the electromagnetic sensor and the laser sensor are integrated together, the center line of the electromagnetic sensor and the emission beam of the laser sensor present a fixed angle θ; The output value of the electromagnetic sensor is ye, and the output value of the laser sensor is yc'; The distance from the sample surface to the reference end face is yc=ye-y0c; Based on the cosine theorem: cosθ=yc / yc'; Therefore, the angle θ=arccos((ye-y0c) / yc'); Subsequent measurements use the angle θ to correct the laser sensor's output value, yc', by multiplying yc' by cosθ. Due to machining and assembly precision, it's difficult to completely align the measurement axes of the electromagnetic and laser sensors. Consequently, a certain angle exists between the electromagnetic and laser sensor's measurement axes. To minimize the impact of this angle on measurement accuracy, this angle is calibrated after the tire inner wall film thickness non-contact measurement sensor is fabricated. This is then used to correct the laser sensor's measurements.

[0017] The present invention also discloses a non-contact detection system for the thickness of the film on the inner wall of a tire, which utilizes the above-mentioned non-contact detection sensor for the thickness of the film on the inner wall of a tire, and includes a multi-axis mechanical arm and a micro motion device; The multi-axis robotic arm is fixedly arranged above the tire conveyor belt, and the multi-axis robotic arm includes a vertical rotation joint arranged at the top and a horizontal rotation joint arranged at the bottom; The micro-motion device is arranged at the end of the horizontal rotary joint, and the horizontal rotary joint is used to control the micro-motion device to rotate up and down around its own rotation axis, and the vertical rotary joint is used to control the micro-motion device to rotate horizontally around its own rotation axis; The micro-motion device includes an extended support arm and a rotation drive mechanism, one end of the extended support arm is rotatably arranged at the end of a horizontal rotation joint, and the tire inner wall film thickness non-contact detection sensor is rotatably arranged at the other end of the extended support arm via a rotation axis; The measurement center line of the tire inner wall film thickness non-contact detection sensor is perpendicular to the rotation axis of the horizontal rotation joint; The rotary drive mechanism, mounted on the extended support arm, controls the vertical rotation of the non-contact tire inner wall film thickness detection sensor around a rotation axis. The present invention utilizes a micro-motion device to increase biaxial motion. The extended support arm extends the sensor into the tire. A horizontal rotary joint adjusts the distance between the sensor and the tire inner wall and its position within the tire. The rotary drive mechanism controls the sensor's measurement angle, aligning the sensor's measurement axis with the tire inner wall. This accommodates the requirements of a small internal tire space and the need for the measurement direction to align with the normal direction of the tire inner wall. The detection system outputs a 3D curve of tire inner liner thickness. By securing the tire on a tire conveyor belt using a centering device, the tire inner wall can be measured directly on the conveyor belt, enabling online detection of tire inner wall thickness without affecting the tire detection cycle.

[0018] The present invention uses a micro-motion device to control the non-contact detection sensor of the thickness of the tire inner wall film to rotate around the rotation axis, reducing the space requirement of the rotation movement and overcoming the problem that the existing robot arm cannot perform small space angle control.

[0019] Preferably, the rotary drive mechanism includes a passive wheel, a driving wheel, an auxiliary wheel, a driving belt and a rotary motor, and the outer diameter of the passive wheel is larger than the outer diameter of the driving wheel; The passive wheel is coaxially arranged with the rotating shaft, and the housing is fixed on the passive wheel; The driving wheel and the auxiliary wheel are rotatably arranged on the extended support arm, the two auxiliary wheels are located between the driven wheel and the driving wheel, and the driving belt is sleeved on the outer sides of the driven wheel, the driving wheel and the auxiliary wheel; The rotary motor is fixed to the extended support arm, and the driving wheel is connected to the motor shaft of the rotary motor. The present invention utilizes a driven wheel, a driving wheel, and an auxiliary wheel in conjunction with a drive belt to drive the sensor, causing it to rotate about the rotation axis. This allows the rotary motor to be positioned at the end of the extended support arm located outside the tire, reducing the required measurement space. In the present invention, the outer diameter of the driven wheel is larger than that of the driving wheel. This reduces the power of the rotary motor and further reduces its size.

[0020] The inventive concept of the present invention is as follows: both electromagnetic sensors and laser sensors are non-contact measurements, but electromagnetic sensors are smaller in size and are more suitable for use in small spaces and small ranges; while laser sensors are mostly triangular reflection type, requiring a larger measurement space and are not very suitable for use in small spaces.

[0021] Since the measuring range of the electromagnetic sensor is positively correlated with the diameter of its internal coil, in order to meet the measurement range requirements, under the premise of reducing the overall size of the sensor of the present invention, the maximum outer diameter of the electromagnetic sensor is limited, and the inner diameter size of the measuring channel is also limited; in terms of measurement range, under the premise of not limiting the size, the measuring range of the electromagnetic sensor is smaller than the measuring range of the laser sensor, but since the size of the measuring channel used for laser sensor measurement limits the measuring range of the laser sensor, in order to increase the measuring range of the laser sensor while reducing the size of the laser sensor to meet the measurement range requirements of the laser sensor, the present invention adjusts the positions of the corresponding transmitting lens and receiving lens of the laser sensor, reduces the distance between the transmitting lens and the receiving lens, and sets a reflector in the measurement channel at the center of the electromagnetic sensor, thereby increasing the emission optical path of the laser beam, thereby increasing the measurement range of the laser sensor, and meeting the measurement requirements of the inner wall thickness of the tire while reducing the volume.

[0022] Compared with the prior art, the present invention has the following beneficial effects: the present invention integrates an electromagnetic sensor and a laser displacement sensor on a housing to non-contactly measure the thickness of the tire's inner wall. A measurement channel is provided axially at the center of the electromagnetic sensor, and a laser sensor is used to measure the tire's inner liner rubber layer through the measurement channel. The electromagnetic sensor is also used to measure the tire's mesh metal layer. While meeting the measurement range and accuracy requirements of the electromagnetic sensor and the laser displacement sensor, the dimensions of each can be reduced simultaneously, allowing the combined sensor to have a diameter of less than 40 mm and a height of less than 80 mm. This allows the detection sensor to penetrate deeply into the tire and achieve wide-angle rotation within the tire, allowing for measurements of the tire's inner wall at various locations on the tread, sidewall, and shoulder, making it suitable for use in environments where the tire's internal space is limited.

[0023] In addition, the laser sensor of the present invention is located on the opposite side of the measuring end face of the electromagnetic sensor, and the housing is made of non-metallic material, which can avoid interference with the measurement of the electromagnetic sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic structural diagram of a non-contact sensor for detecting thickness of a film on the inner wall of a tire according to Example 1 of the present invention; Figure 2 This is a schematic structural diagram of a non-contact sensor for detecting the thickness of a film on the inner wall of a tire according to embodiment 2 of the present invention; Figure 3 This is a schematic structural diagram of the non-contact detection system for the thickness of the tire inner wall film according to the present invention; Figure 4 Schematic diagram of the connection structure between the multi-axis robotic arm and the micro motion device of the present invention; Figure 5 Schematic diagram of the structure of the micro-motion device of the present invention; Figure 6 Schematic diagram of the non-contact detection method for the thickness of the film on the inner wall of a tire according to the present invention; Figure 7 A schematic diagram of calibration of the non-contact detection method for the thickness of the tire inner wall film according to the present invention; Figure 8 Schematic diagram of triangulation measurement of the non-contact detection method for tire inner wall film thickness according to Example 2 of the present invention; Figure 9 Schematic diagram of triangulation measurement of the non-contact detection method for tire inner wall film thickness according to Example 3 of the present invention; In the figure, 100 housing, 1 electromagnetic sensor, 2 laser sensor; 11 measurement channels; 21 transmitting lens, 22 receiving lens, 3 reflecting mirror; 4 mounting bracket, 5 tire, 200 reference end surface, 51 mesh metal layer, 52 inner lining rubber layer; 6 multi-axis robotic arms, 7 micro motion devices, 8 tire conveyor belts; 61 vertical rotation joint, 62 horizontal rotation joint; 71 extended support arm, 72 rotation drive mechanism; 9 rotation axis; 721 passive wheel, 722 driving wheel, 723 auxiliary wheel, 724 driving belt, 725 rotating motor; 300 fixed bracket. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0026] Example 1 like Figure 1 As shown, a non-contact detection sensor for the thickness of the film on the inner wall of a tire includes a housing 100 , an electromagnetic sensor 1 and a laser sensor 2 .

[0027] A measurement channel 11 is axially disposed through the center of the electromagnetic sensor 1. In this embodiment, the measurement centerline of the electromagnetic sensor 1 coincides with the centerline of the measurement channel 11. The electromagnetic sensor 1 utilizes a coil made of a special material to generate an alternating magnetic field. The displacement of the metal material causes the magnetic field to change, and the displacement is output through slight changes in the coil current. The coils are circular and distributed outside the sensor to ensure physical centerline overlap. In this embodiment, the electromagnetic sensor 1 utilizes an eddy current sensor.

[0028] The laser sensor 2 is integrated with the electromagnetic sensor 1 and is disposed on the housing 100 . The laser sensor 2 is located on the opposite side of the measuring end face of the electromagnetic sensor 1 .

[0029] In this embodiment, the emission light beam of the laser sensor 2 coincides with the measurement center line of the electromagnetic sensor 1 , and the laser sensor 2 performs measurement through the measurement channel 11 .

[0030] The laser sensor 2 includes a transmitting lens 21 and a receiving lens 22. A reflector 3 is disposed within the measurement channel 11. In this embodiment, the reflector 3 is a plane mirror, and both the housing 100 and the reflector 3 are made of non-metallic materials. The housing 100 is made of a non-metallic, hard material with strong magnetic field penetration, making it easy to process. Because the material within the measurement channel 11 can affect the accuracy of the electromagnetic sensor 1, the reflector 3 is primarily made of glass. Ordinary glass is primarily composed of silicon dioxide (SiO2), which is neither ferromagnetic nor paramagnetic, and therefore does not actively affect the magnetic field.

[0031] The emitting lens 21 is used to emit laser light along the axial direction of the measuring channel 11 .

[0032] The receiving lens 22 is used to receive the light beam reflected by the reflector 3. In this embodiment, in order to reduce the size of the laser sensor, the positions of the transmitting lens 21 and the receiving lens 22 of the laser sensor 2 are adjusted. The other structures and working principles are the same as those in the prior art and will not be repeated here.

[0033] The tire inner wall film thickness non-contact detection sensor further includes a mounting bracket 4 , which is made of non-metallic material, and the reflector 3 is mounted on the mounting bracket 4 .

[0034] The mounting bracket 4 is detachably mounted in the measuring channel 11 .

[0035] like Figure 1 As shown, in this embodiment, due to the relatively small thickness of the electromagnetic sensor 1, there is only one reflector 3. Different measurement ranges of the laser sensor require different reflection optical paths. If the reflection optical path interferes with the inner wall of the measurement channel 11, additional reflectors are required. The number of reflectors depends on the numerical value of the reflection optical path, until the reflected laser is received by the CMOS chip of the laser sensor. In the present invention, the sum of the reflection path lengths of the light beams received by the receiving lens 22 is equal to the reflection path length of the laser emitted by the laser sensor 2 in the laser triangulation method. Here, the reflection path length in the laser triangulation method is equal to the distance from the laser spot on the surface of the object to the receiving lens, and the sum of the reflection path lengths of the light beams received by the receiving lens 22 is the optical path length from the laser spot on the surface of the object to the receiving lens.

[0036] In this embodiment, the laser beam emitted by the laser sensor 2 and the reflected beam do not intersect with each other, and the laser sensor 2 can emit the laser and receive the reflected beam at the same time.

[0037] The present invention integrates a laser sensor and an electromagnetic sensor into one. In order to ensure the detection range and detection distance of the fused sensor, the electromagnetic sensor 1 is arranged in front of the measuring end face of the laser sensor 2, and a measurement channel 11 for the laser sensor 2 to measure is arranged in the center of the coil of the electromagnetic sensor 1. At the same time, in order to ensure that the diameter of the measurement channel 11 is minimized, that is, the diameter of the electromagnetic sensor 1 is limited, thereby ensuring that the diameter of the overall fusion sensor is small, the laser sensor adopts a special light reflection method, which is reflected multiple times by a plane mirror. This ensures that the light does not introduce aberrations and the modular adjustment is simple. This structural innovation ensures that the fusion sensor is small in size. The diameter of the measurement channel 11 ensures that the laser line accurately penetrates the middle part of the electromagnetic sensor 1 while ensuring that the diameter of the electromagnetic sensor 1 is minimized. Non-metallic fixings and adhesives are selected to fix the reflector to ensure that there are no metal components in the measurement channel 11. Because metal components interfere with the magnetic field distribution, the intensity and direction change, resulting in nonlinearity of the received signal, especially the unstable magnetic field signal change has a random impact on the measurement accuracy, which is the main factor leading to the instability of the measurement sensor. In this embodiment, the axial length of the tire inner wall film thickness non-contact detection sensor reaches 80 mm, and the maximum diameter is 40 mm. From a theoretical point of view, the smaller the diameter of the measurement channel 11, the better. However, considering the comprehensive parameter index requirements and the difficulty of structural processing, in this embodiment, the diameter of the measurement channel 11 is 6 mm.

[0038] The mounting bracket 4 is interference-fitted in the measuring channel 11 or adhered to the measuring channel 11 by fixing glue. In this embodiment, the mounting bracket 4 is an annular structure, and the reflector 3 is mounted on the inner wall of the mounting bracket 4 .

[0039] like Figure 6 As shown, a non-contact detection method for the thickness of the film on the inner wall of the tire is provided. The non-contact detection sensor for the thickness of the film on the inner wall of the tire is inserted into the interior of the tire 5 by using the non-contact detection sensor for the thickness of the film on the inner wall of the tire. The position and angle of the non-contact detection sensor for the thickness of the film on the inner wall of the tire are adjusted so that the axis of the measurement channel 11 is perpendicular to the inner wall of the tire 5, and the positions to be measured are all within the measurement range of the electromagnetic sensor 1 and the laser sensor 2.

[0040] The measuring end face of the electromagnetic sensor 1 is used as the reference end face 200 , and the electromagnetic sensor 1 is used to measure the distance ye from the reference end face 200 to the surface of the mesh metal layer 51 of the tire 5 .

[0041] Given the fixed distance between the measuring end face of electromagnetic sensor 1 and the measuring end face of laser sensor 2, the distance yc' between the measuring end face of laser sensor 2 and the surface of the inner liner 52 of the tire 5 is measured. Specifically, the distance yc' between the reference end face 200 and the surface of the inner liner 52 of the tire 5 is obtained by subtracting the fixed distance between the measuring end face of electromagnetic sensor 1 and the measuring end face of laser sensor 2 from the distance between the measuring end face of laser sensor 2 and the surface of the inner liner 52 of the tire 5.

[0042] Then, the thickness value y0 from the surface of the inner lining rubber layer 52 to the surface of the mesh metal layer 51 is y0=ye−yc′.

[0043] like Figure 7 As shown, the thickness value y0 is calibrated using a sample with a standard thickness of y0c from the surface of the inner lining rubber layer 52 to the surface of the mesh metal layer 51. Specifically: After the electromagnetic sensor 1 and the laser sensor 2 are integrated together, the center line of the electromagnetic sensor 1 and the emission light beam of the laser sensor 2 form a fixed angle θ.

[0044] The output value of electromagnetic sensor 1 is ye, and the output value of laser sensor 2 is yc'.

[0045] The distance yc from the sample surface to the reference end surface 200 is ye-y0c.

[0046] Based on the cosine theorem: cosθ=yc / yc'.

[0047] Therefore, the included angle θ=arccos((ye-y0c) / yc') is deduced.

[0048] In subsequent measurements, the angle θ is used to correct the value yc' output by the laser sensor 2, that is, yc' is multiplied by cosθ.

[0049] like Figure 3 and Figure 4 As shown, a non-contact detection system for the thickness of the film on the inner wall of a tire utilizes the above-mentioned non-contact detection sensor for the thickness of the film on the inner wall of a tire, and includes a multi-axis robotic arm 6 and a micro motion device 7.

[0050] In this embodiment, the tire conveyor belt 8 is a roller conveyor belt, and the multi-axis robotic arm 6 is a six-axis robotic arm. The multi-axis robotic arm 6 is fixedly disposed above the tire conveyor belt 8. Specifically, a fixed bracket 300 is disposed above the tire conveyor belt 8, and the multi-axis robotic arm 6 is mounted on the fixed bracket 300. The multi-axis robotic arm 6 includes a vertical rotation joint 61 disposed at the top and a horizontal rotation joint 62 disposed at the bottom. In this embodiment, the multi-axis robotic arm 6 is a six-axis robotic arm. In this embodiment, the tire 5 is placed horizontally on the tire conveyor belt 8, and the centering device is used to fix the tire 5 transported above the tire conveyor belt 8, so that online measurement of the tire 5 can be achieved. In this embodiment, the centering device includes an arc-shaped clamping plate arranged above the tire conveyor belt 8, and the two arc-shaped clamping plates are arranged opposite to each other. The two arc-shaped clamping plates are respectively driven by a hydraulic telescopic rod or an electric telescopic rod, and the hydraulic telescopic rod or the electric telescopic rod is horizontally arranged on the fixed bracket 300 (not shown in the figure), which is used to clamp and fix the outer side of the tire 5. During the operation of the tire conveyor belt 8, the tire 5 is fixed, and the measurement of the non-contact detection sensor of the thickness of the tire inner wall film will not be interfered with, thereby achieving online measurement of the tire 5.

[0051] The micro-motion device 7 is arranged at the end of the horizontal rotation joint 62, and the rotation axis of the horizontal rotation joint 62 is arranged horizontally. The horizontal rotation joint 62 is used to control the micro-motion device 7 to perform up and down rotation movement around its own rotation axis. The rotation axis of the vertical rotation joint 61 is arranged vertically. The vertical rotation joint 61 is used to control the micro-motion device 7 to perform horizontal rotation movement around its own rotation axis.

[0052] like Figure 3 As shown, the micro-motion device 7 includes an extended support arm 71 and a rotation drive mechanism 72. One end of the extended support arm 71 is rotatably set at the end of the horizontal rotation joint 62, and the tire inner wall film thickness non-contact detection sensor is rotatably set at the other end of the extended support arm 71 through the rotating shaft 9.

[0053] The measurement center line of the tire inner wall film thickness non-contact detection sensor is perpendicular to the rotation axis of the horizontal rotation joint 62 .

[0054] The rotation drive mechanism 72 is provided on the extended support arm 71 and is used to control the non-contact detection sensor for the thickness of the film on the inner wall of the tire to rotate up and down around the rotation axis 9 .

[0055] like Figure 5 As shown, the rotary drive mechanism 72 includes a driven wheel 721 , a driving wheel 722 , an auxiliary wheel 723 , a driving belt 724 and a rotary motor 725 . The outer diameter of the driven wheel 721 is greater than the outer diameter of the driving wheel 722 .

[0056] The driven wheel 721 is sleeved on the outside of the rotating shaft 9 . The driven wheel 721 and the rotating shaft 9 are coaxially arranged. The housing 100 is fixed on the driven wheel 721 .

[0057] The driving wheel 722 and auxiliary wheel 723 are rotatably mounted on the extended support arm 71. The two auxiliary wheels 723 are positioned between the driven wheel 721 and the driving wheel 722. The drive belt 724 is sleeved around the outer sides of the driven wheel 721, the driving wheel 722, and the auxiliary wheels 723. In this embodiment, the two auxiliary wheels 723 are spaced apart from each other from top to bottom, with the maximum distance between the outer rings of the two auxiliary wheels 723 being equal to the outer diameter of the driven wheel 721. This supports the middle of the drive belt 724, allowing for a weight-reducing hole to be provided in the middle of the extended support arm 71, reducing the overall weight of the micro-motion device 7 and enabling flexible control of the non-contact tire inner wall film thickness detection sensor.

[0058] The rotating motor 725 is fixed on the extended support arm 71 , and the driving wheel 722 is connected to the motor shaft of the rotating motor 725 .

[0059] The present invention is mainly used to measure the thickness of the inner wall of the tire. The inner wall of the tire has a complex curved surface shape. The sensor needs to be perpendicular to the tangent direction of the curved surface to accurately measure. Therefore, the sensor is installed at the end of a robotic arm, that is, a multi-axis robotic arm 6. In order to ensure that the robotic arm can reach the narrow inner wall space of the tire, a micro-motion device 7 is added to the end of the robotic arm. The device is installed at the end of the six-axis robotic arm and performs biaxial motion according to the detection position. It automatically adjusts the movement posture of the sensor in the horizontal direction and the rotation angle direction to achieve the main axis of the sensor being perpendicular to the tangent direction of the inner wall surface of the tire and moving along a preset trajectory for measurement, such as Figure 3-Figure 5 The figure shows the structural principle of the micro motion device.

[0060] The detection system of the present invention is able to adjust the angle and position of the sensor inside the tire because it integrates a six-axis robotic arm with two additional axes (each with a diameter less than 60 mm), creating an eight-axis system. This allows the sensor to rotate freely inside the tire and accurately measure the inner liner thickness along the normal line of the tire's inner wall. The large diameter of the distal end of the mainstream six-axis robotic arm prevents it from reaching the inside of the tire. Even if it could, the rotational movement of the standard robotic arm's rotary joints cannot ensure that the direction of motion of the sensor distal end joint aligns with the normal line of the tire's inner wall. The narrow space inside the tire makes it impossible to achieve the required inner wall detection. The present invention utilizes a micro-motion device 7 and a multi-axis robotic arm 6 to control the sensor to adjust the detection position and angle.

[0061] Example 2 like Figure 2As shown, the difference from Example 1 is that the tire inner wall film thickness non-contact detection sensor has three reflectors 3.

[0062] The reflectors 3 are arranged at intervals along the axial direction of the measuring channel 11 .

[0063] To prevent the reflected beam from affecting the transmitted beam, this embodiment provides a mounting bracket 4 within measurement channel 11 for mounting a reflector 3, thereby forming an independent reflection channel within measurement channel 11. In this embodiment, the laser beam emitted by laser sensor 2 and the reflected beam do not intersect with each other, allowing laser sensor 2 to transmit laser light and receive reflected beams simultaneously.

[0064] Figure 8 This is a schematic diagram of the reflection of the received light. The total optical path of the reflection is equivalent to the path of the received light. For the detection sensor, the detection range is determined according to the application requirements. The total optical path is calculated by the triangulation principle. Due to the limitation of the diameter of the measurement channel 11, the number of reflectors 3, i.e. the number of split optical paths, is determined. Figure 8 There are four optical paths. Assuming the lengths of each optical path are L1, L2, L3, and L4, the total optical path is L = L1 + L2 + L3 + L4. That is, the distance from the center of the light spot on the measured surface to the main surface of the receiving lens is L, and the distance from the main surface of the receiving lens to the center of the receiving light spot on the photosensitive element changes with L. This makes the position change of the measured surface linearly related to the displacement of the measured light point on the photosensitive element. Once the displacement of the measured light point on the photosensitive element is measured, the coordinates of the corresponding point on the measured surface can be calculated, thereby achieving distance measurement. Through this embodiment, the radial dimension of the laser sensor 2 can be reduced from H to H1.

[0065] Example 3 The difference from Example 1 is that the tire inner wall film thickness non-contact detection sensor has two reflectors 3, and the two reflectors 3 are located on both sides of the light beam emitted by the laser sensor 2. The reflectors 3 are arranged on both sides of the light beam emitted by the laser sensor 2, which can increase the reflection optical path of the laser sensor when the number of reflectors 3 is the same. However, the reflected light beams will be intertwined with each other. In order to avoid mutual influence between the reflected light beams, different pulses can be used to control the emission and reception of the laser, so that the emission and reception of the laser beam are staggered in time.

[0066] In this embodiment, the number of split light paths is three, such as Figure 9 As shown, assuming that the length of each optical path is L1, L2, L3, the total optical path is L=L1+L2+L3. Figure 9As shown, arranging the reflectors 3 on both sides of the light beam emitted by the laser sensor 2 helps to further reduce the distance between the emitting lens 21 and the receiving lens 22. Through this embodiment, the radial dimension of the laser sensor 2 can be reduced from H to H1.

Claims

1. A non-contact sensor for detecting the thickness of the film on the inner wall of a tire, characterized by: It comprises a housing (100), an electromagnetic sensor (1) and a laser sensor (2), wherein the housing (100) is made of a non-metallic material; A measuring channel (11) is provided in the center of the electromagnetic sensor (1) along the axial direction; The laser sensor (2) and the electromagnetic sensor (1) are integrated and arranged on the housing (100), and the laser sensor (2) is located on the side opposite to the measuring end face of the electromagnetic sensor (1); The laser sensor (2) performs measurement through a measurement channel (11).

2. The non-contact detection sensor for tire inner wall film thickness according to claim 1, characterized in that: The laser sensor (2) comprises a transmitting lens (21) and a receiving lens (22), and a reflector (3) is provided in the measuring channel (11); The emission lens (21) is used to emit laser light along the axial direction of the measurement channel (11); The receiving lens (22) is used to receive the light beam reflected back by the reflector (3).

3. The non-contact detection sensor for tire inner wall film thickness according to claim 2, characterized in that: It also includes a mounting bracket (4), the mounting bracket (4) is made of a non-metallic material, and the reflector (3) is mounted on the mounting bracket (4); The mounting bracket (4) is detachably mounted in the measuring channel (11).

4. The non-contact detection sensor for tire inner wall film thickness according to claim 3, characterized in that: The mounting bracket (4) is interference-mounted in the measuring channel (11) or adhered to the measuring channel (11).

5. The non-contact detection sensor for tire inner wall film thickness according to claim 2, characterized in that: There are more than one reflector (3).

6. The non-contact detection sensor for tire inner wall film thickness according to claim 2, characterized in that: The sum of the reflection path lengths of the light beams received by the receiving lens (22) is equal to the reflection path length of the laser emitted by the laser sensor (2) in the laser triangulation method.

7. A method for non-contact detection of tire inner wall film thickness, using the tire inner wall film thickness non-contact detection sensor according to any one of claims 1 to 6, characterized in that: Inserting the tire inner wall film thickness non-contact detection sensor into the tire (5), adjusting the position and angle of the tire inner wall film thickness non-contact detection sensor so that the axis of the measurement channel (11) is perpendicular to the inner wall of the tire (5), and the positions to be measured are all located within the measurement range of the electromagnetic sensor (1) and the laser sensor (2); Taking the measuring end face of the electromagnetic sensor (1) as the reference end face (200), the electromagnetic sensor (1) is used to measure the distance ye from the reference end face (200) to the surface of the mesh metal layer (51) of the tire (5); The fixed distance between the measuring end face of the electromagnetic sensor (1) and the measuring end face of the laser sensor (2) is known, and the distance yc' from the reference end face (200) to the surface of the inner lining rubber layer (52) of the tire (5) is obtained by measuring the distance from the measuring end face of the laser sensor (2) to the surface of the inner lining rubber layer (52) of the tire (5); Then the thickness value y0 from the surface of the inner lining rubber layer (52) to the surface of the mesh metal layer (51) is ye-yc'.

8. The non-contact detection method for tire inner wall film thickness according to claim 7, characterized in that: The thickness value y0 is calibrated using a sample with a standard thickness of y0c from the surface of the inner lining rubber layer (52) to the surface of the mesh metal layer (51), specifically: After the electromagnetic sensor (1) and the laser sensor (2) are integrated together, the center line of the electromagnetic sensor (1) and the emission light beam of the laser sensor (2) present a fixed angle θ; The output value of the electromagnetic sensor (1) is ye, and the output value of the laser sensor (2) is yc'; The distance from the sample surface to the reference end surface (200) is yc=ye-y0c; Based on the cosine theorem: cosθ=yc / yc'; Therefore, the angle θ=arccos((ye-y0c) / yc'); In subsequent measurements, the angle θ is used to correct the value yc' output by the laser sensor (2), that is, yc' is multiplied by cosθ.

9. A non-contact detection system for tire inner wall film thickness, utilizing the tire inner wall film thickness non-contact detection sensor according to any one of claims 1 to 6, characterized in that: It includes a multi-axis robotic arm (6) and a micro motion device (7); The multi-axis robot arm (6) is fixedly arranged above the tire conveyor belt (8), and the multi-axis robot arm (6) includes a vertical rotation joint (61) arranged at the top and a horizontal rotation joint (62) arranged at the bottom; The micro-motion device (7) is arranged at the end of a horizontal rotation joint (62), and the horizontal rotation joint (62) is used to control the micro-motion device (7) to perform vertical rotational movement around its own rotation axis, and the vertical rotation joint (61) is used to control the micro-motion device (7) to perform horizontal rotational movement around its own rotation axis; The micro-motion device (7) comprises an extended support arm (71) and a rotation drive mechanism (72), one end of the extended support arm (71) being rotatably disposed at the end of a horizontal rotation joint (62), and the tire inner wall film thickness non-contact detection sensor being rotatably disposed at the other end of the extended support arm (71) via a rotation shaft (9); The measurement center line of the tire inner wall film thickness non-contact detection sensor is perpendicular to the rotation axis of the horizontal rotation joint (62); The rotation drive mechanism (72) is arranged on the extended support arm (71) and is used to control the non-contact detection sensor for the thickness of the film on the inner wall of the tire to rotate up and down around the rotation axis (9).

10. The non-contact detection system for tire inner wall film thickness according to claim 9, characterized in that: The rotary drive mechanism (72) comprises a driven wheel (721), a driving wheel (722), an auxiliary wheel (723), a driving belt (724), and a rotary motor (725); the outer diameter of the driven wheel (721) is larger than the outer diameter of the driving wheel (722); The passive wheel (721) is coaxially arranged with the rotating shaft (9), and the housing (100) is fixed on the passive wheel (721); The driving wheel (722) and the auxiliary wheel (723) are rotatably arranged on the extended support arm (71), the two auxiliary wheels (723) are located between the driven wheel (721) and the driving wheel (722), and the driving belt (724) is sleeved on the outside of the driven wheel (721), the driving wheel (722) and the auxiliary wheel (723); The rotating motor (725) is fixed on the extended support arm (71), and the driving wheel (722) is connected to the motor shaft of the rotating motor (725).

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