A thin film sensor measuring module for heavy load pressure measurement and assembly method

Abstract

The application relates to the field of heavy-load tire pressure measurement, in particular to a film sensor measurement module for heavy-load pressure measurement and an assembling method. The measurement module comprises a rigid base layer, a first flexible pad layer arranged on the rigid base layer, a lower surface of the first flexible pad layer being fixedly attached to the rigid base layer, a film pressure sensor arranged on the first flexible pad layer, the film pressure sensor having an effective sensing area and a non-sensing area, a second flexible pad layer arranged on the film pressure sensor, the thickness of the second flexible pad layer being greater than that of the first flexible pad layer, an integrated collector arranged at an end edge of the rigid base layer, the integrated collector being provided with a detachable fastening cover plate, and the non-sensing area being provided with an adhesive layer for bonding the first flexible pad layer and the second flexible pad layer. Under the condition of meeting the physical performance of heavy-load detection, the film pressure sensor is protected, the interference of pressure transmission is reduced, the sensor can be conveniently replaced, and the functions are coordinated.

Description

Technical Field

[0001] This application relates to the field of heavy-duty tire pressure measurement, and more particularly to a thin-film sensor measurement module and assembly method for heavy-duty pressure measurement. Background Technology

[0002] In the field of heavy-duty tire ground pressure measurement, thin-film pressure sensors are widely used due to their thinness, flexibility, and high resolution. However, because the sensors themselves are thin (typically about 0.6 mm) and fragile, they are easily damaged under heavy-duty (e.g., 15-ton axle load / 300 psi) tire rolling conditions, and usually need to be encapsulated in a protective structure to provide cushioning protection.

[0003] However, the above-mentioned needs are mutually restrictive and contradictory, making it difficult to satisfy them simultaneously: To protect the sensor, a buffer layer of sufficient thickness needs to be set on the pressure side to attenuate the impact load and provide stable support at the bottom. However, the thicker the buffer layer and the tighter the encapsulation structure, the longer the pressure transmission path, which may introduce elastic deformation error and impair measurement accuracy. Conversely, if the thickness of the buffer layer is reduced or the sensor is placed as close as possible to the pressure surface, although it helps to improve the fidelity of pressure transmission, it weakens the buffer protection effect.

[0004] On the other hand, to ensure that the encapsulation structure does not undergo interlayer peeling or relative displacement under heavy load, the sensor is usually firmly fixed to the upper and lower flexible pads, which to some extent interferes with the accuracy of pressure measurement.

[0005] Furthermore, once the sensor is fully encapsulated and welded to the data acquisition unit, it forms a highly integrated structure. When replacing it, the entire stacked structure needs to be disassembled, which is time-consuming and has a significant impact on surrounding components. If the fixed connection is reduced or the encapsulation structure is loosened in order to pursue convenient replacement, the sensor's protective performance and measurement stability will be difficult to maintain.

[0006] Therefore, the technical problem to be solved in this application is how to effectively protect the fragile thin-film pressure sensor, reduce the interference of pressure transmission in the sensing area, and make the sensor easy to replace, based on heavy-duty tire crushing test. Summary of the Invention

[0007] To address the aforementioned issues, this application aims to provide a thin-film sensor measurement module for heavy-duty pressure measurement. This module effectively protects the fragile thin-film pressure sensor while reducing interference in pressure transmission within the sensing area, all while meeting the physical performance requirements for heavy-duty detection. It also enables convenient sensor replacement, achieving functional synergy.

[0008] To achieve the above objectives, the technical solution adopted in this application is as follows: A thin-film sensor measurement module for heavy-duty pressure measurement includes: a rigid base layer; a first flexible pad layer disposed on the rigid base layer, the lower surface of the first flexible pad layer being fixedly attached to the rigid base layer; a thin-film pressure sensor disposed on the first flexible pad layer, the thin-film pressure sensor having an effective sensing area and a non-sensing area surrounding the effective sensing area; and a second flexible pad layer disposed on the thin-film pressure sensor, the second flexible pad layer being connected to the edge of the first flexible pad layer, and a space between the second flexible pad layer and the first flexible pad layer for transmitting the thin-film pressure. A lateral opening for sensor insertion and removal; an integrated collector disposed at the end edge of the rigid base layer, the integrated collector being equipped with a removable fastening cover, and one side of the thin-film pressure sensor extending into the fastening cover through the lateral opening; wherein, the non-sensing area is provided with an adhesive layer bonded to the first flexible pad and the second flexible pad, and the effective sensing area is bonded to the second flexible pad and the first flexible pad respectively without adhesive; the fastening cover is configured such that, when opened, the thin-film pressure sensor can be pulled out from between the first flexible pad and the second flexible pad.

[0009] This technology enables the measurement module to form a multi-layered composite support structure from bottom to top. The rigid base layer provides the basic load-bearing rigidity for the whole. The first flexible pad layer forms a transition buffer between the rigid base layer and the thin-film pressure sensor, which helps to disperse the concentrated stress generated when the heavy-duty tire rolls over it and reduces the risk of damage to the thin-film pressure sensor due to hard contact at the bottom. The second flexible pad layer, with its relatively large thickness, is set on the pressure side of the thin-film pressure sensor, which can form a more sufficient mechanical buffer space between the tire and the sensor, which helps to attenuate the peak value of the impact load. The integrated data acquisition unit is placed at the end edge of the rigid base layer and forms an elastic electrical contact with the sensor lead-out end through a conductive pin. With the help of the positioning sleeve hole to limit the sensor end and the detachable fastening cover plate to press and fix it, it not only achieves reliable electrical connection and accurate positioning between the sensor and the data acquisition unit, but also reserves operating space for independent replacement of the sensor.

[0010] Specifically, by setting the adhesive layer only in the non-sensing area to keep the effective sensing area in a glue-free state, the thin-film pressure sensor is secured by the upper and lower flexible pads while avoiding interference from the adhesive layer on the pressure transmission in the effective sensing area, thus helping to maintain the accuracy of pressure measurement. In addition, the fastening cover is designed as a detachable structure. When the fastening cover is opened and the contact pressure of the conductive pin is released, the thin-film pressure sensor can be pulled out laterally from the glue-free area. This allows for quick sensor replacement without disassembling the entire stacked structure of the measurement module, which shortens maintenance time and reduces the impact on surrounding components to a certain extent.

[0011] Furthermore, the thickness ratio of the second flexible pad to the first flexible pad is 2:1 to 3:1.

[0012] This technique controls the thickness ratio of the second flexible pad to the first flexible pad within the range of 2:1 to 3:1, making the buffer thickness on the pressure side significantly greater than the transition thickness on the support side. This helps to provide more elastic deformation space on the tire-pressed side to absorb and disperse impact energy, while avoiding the problem of insufficient sensor support and excessive deflection caused by an excessively thick lower transition layer. It balances the sensor's side protection requirements with bottom support stability.

[0013] Furthermore, the thickness of the second flexible pad is 0.4 cm to 0.6 cm, and the thickness of the first flexible pad is 0.15 cm to 0.25 cm.

[0014] By using this technique, the thickness of the second flexible pad is limited to 0.4 cm to 0.6 cm, and the thickness of the first flexible pad is limited to 0.15 cm to 0.25 cm. Combined with the thickness of the thin-film pressure sensor itself, this helps to control the overall packaging thickness of the measurement module within a relatively thin range. While meeting the requirements for heavy-duty pressure protection, it minimizes the occupation of the original space conditions of the test bench and facilitates the consistency of the vehicle's lateral height when working with the auxiliary pad.

[0015] Furthermore, the rigid base layer is made of aluminum alloy, and the opposite two edges of the rigid base layer are respectively provided with a slope transition structure with gradually decreasing thickness.

[0016] This technology utilizes an aluminum alloy rigid base layer, ensuring sufficient structural strength and compressive strength while reducing the overall weight of the measurement module. This facilitates on-site installation, position adjustment, and disassembly and storage. Gradually decreasing slope transition structures are incorporated into the opposite edges of the rigid base layer. When a tire enters or exits from one side of the measurement module, the slope provides guidance and transitional support, reducing the impact of step contact between the tire and the module's edge. This minimizes stress concentration at the edge, reducing its adverse effects on the internal thin-film pressure sensor, and provides protection for both the tire and the measurement module itself.

[0017] Furthermore, a transverse sliding groove is provided at the bottom of the rigid base layer.

[0018] This technique involves creating a transverse sliding groove at the bottom of the rigid base layer. This groove can cooperate with the fixing bolts or other positioning components on the test bench floor, allowing the measuring module to slide and adjust its installation position in the transverse direction. This helps to adapt to different wheel spacings of different wheeled vehicles. When it is necessary to measure the ground pressure of different vehicle models, the measuring module can be moved laterally along the sliding groove to the appropriate position after the fasteners are loosened and then relocked, improving the versatility and adjustment convenience of the measuring module.

[0019] Furthermore, the second flexible pad is made of silicone material and is configured to have a static friction coefficient with the tire rubber of not less than 0.9.

[0020] Through this technical means, the second flexible pad is made of silicone material. The good pressure resistance, temperature resistance and chemical stability of silicone material help maintain the consistency of cushioning performance under the condition of repeated rolling by heavy-duty tires. The static friction coefficient between the second flexible pad and the tire rubber is configured to be not less than 0.9, which can provide greater frictional resistance between the tire and the top surface of the measurement module. This helps to reduce the risk of tire slippage during the measurement process, allowing the tire to pass through the sensing area more stably, and to a certain extent improves the stability and repeatability of pressure measurement.

[0021] This application also provides a method for assembling the measurement module as described above, characterized by the following steps: fixing the lower surface of the first flexible pad to the rigid base layer; placing a thin-film pressure sensor on the first flexible pad, aligning the effective sensing area with the adhesive-free area on the upper surface of the first flexible pad; covering the thin-film pressure sensor with a second flexible pad, aligning the adhesive-free area on the lower surface of the second flexible pad with the effective sensing area, and clamping and fixing the thin-film pressure sensor between the first and second flexible pads using the adhesive layer, ensuring that both the upper and lower surfaces of the effective sensing area are in an adhesive-free bonding state; fixing the edges of the second flexible pad and the first flexible pad, reserving a lateral opening for inserting and removing the thin-film pressure sensor; extending the thin-film pressure sensor to the area outside the first and second flexible pads, connecting it to the integrated acquisition unit, and installing the fastening cover plate.

[0022] This technique involves assembling the sensor layer by layer from bottom to top. First, the first flexible pad is bonded to the rigid base layer to form a stable underlying support platform. Then, the thin-film pressure sensor is placed on the first flexible pad, ensuring the effective sensing area is precisely aligned with the adhesive-free area. Next, the second flexible pad is placed over the sensor, aligning the adhesive-free area on its lower surface with the effective sensing area. Finally, the thin-film pressure sensor is fixed between the two flexible pads by the clamping action of the upper and lower adhesive layers, ensuring that both the upper and lower surfaces of the effective sensing area are in an adhesive-free bond. This clear assembly process and precise positioning requirements help reduce alignment difficulties during assembly, minimize the risk of overlap between the sensing area and adhesive layers due to bonding deviations, and to a certain extent guarantee the pressure measurement performance of the assembled module and the replaceability of the sensor.

[0023] In summary, this application has at least one of the following beneficial effects: 1. This application establishes a transition buffer by setting a first flexible pad between the rigid base layer and the thin-film pressure sensor, and a second flexible pad with a larger thickness on the pressure-bearing side of the thin-film pressure sensor to form a mechanical buffer space. An adhesive layer is only set in the non-sensing area to keep the effective sensing area in a glue-free state. Simultaneously, the integrated acquisition unit is positioned at the edge of the rigid base layer and forms an elastic electrical contact with the sensor lead-out end through a conductive pin. This, combined with a positioning sleeve and a detachable fastening cover, effectively disperses and attenuates impact loads under heavy tire pressure conditions. This reduces the risk of damage to the thin-film pressure sensor due to hard contact at the bottom or instantaneous impact. Furthermore, it effectively avoids interference from the adhesive layer on the pressure transmission in the effective sensing area, maintaining the accuracy of pressure measurement. Moreover, after opening the fastening cover to release the pressure of the conductive pin, the thin-film pressure sensor can be laterally removed from the glue-free area without disassembling the entire stacked structure of the measurement module, enabling rapid sensor replacement. This approach balances the needs for sensor structural protection, measurement accuracy maintenance, and convenient maintenance to a certain extent.

[0024] 2. By controlling the thickness ratio of the second flexible pad to the first flexible pad within the range of 2:1 to 3:1, the buffer thickness on the pressure side is significantly greater than the transition thickness on the support side. This helps to provide more elastic deformation space on the tire-pressing side to absorb and disperse impact energy. At the same time, it avoids the problem of insufficient sensor support and excessive deflection caused by an excessively thick lower transition layer. To a certain extent, it balances the protection requirements of the sensor on the pressure side and the stability of the bottom support.

[0025] 3. By limiting the thickness of the second flexible pad to 0.4 cm to 0.6 cm and the thickness of the first flexible pad to 0.15 cm to 0.25 cm, combined with the thickness of the thin-film pressure sensor itself, it helps to control the overall packaging thickness of the measurement module within a relatively thin range. While meeting the requirements of heavy-duty pressure protection, it minimizes the occupation of the original space conditions of the test bench and facilitates the consistency of the vehicle's lateral height when working with the auxiliary pad.

[0026] 4. The rigid base layer is made of aluminum alloy, which ensures sufficient structural strength and compressive strength while helping to reduce the overall weight of the measurement module, facilitating on-site installation, position adjustment, and disassembly and storage. A gradually decreasing slope transition structure is set on the opposite sides of the rigid base layer. When a tire enters or exits from one side of the measurement module, the slope provides guidance and transition support, helping to reduce the impact of step-like contact between the tire and the edge of the measurement module, reducing stress concentration at the edge and its adverse effects on the internal thin-film pressure sensor, while also providing some protection for both the tire and the measurement module itself. Attached Figure Description

[0027] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the structure of a thin-film sensor measurement module for heavy-duty pressure measurement, which is an optional embodiment of this application. Figure 2 This is a schematic diagram of the hidden integrated data acquisition unit of the thin-film sensor measurement module for heavy-duty pressure measurement, which is an optional embodiment of this application. Figure 3 This is a cross-sectional view of a thin-film sensor measurement module for heavy-duty pressure measurement, which is an optional embodiment of this application. Figure 4 for Figure 3 Enlarged diagram of section A in the middle; Figure 5 This is a schematic diagram of the structure of an optional thin-film pressure sensor according to an embodiment of this application; Figure 6 This is a cross-sectional view of another optional thin-film sensor measurement module for heavy-duty pressure measurement according to an embodiment of this application; Figure 7 for Figure 6 Enlarged schematic diagram of section B.

[0028] The components are: 1. Rigid base layer; 11. Transverse slide groove; 2. First flexible pad layer; 3. Thin film pressure sensor; 31. Effective sensing area; 32. Non-sensing area; 33. Adhesive layer; 4. Second flexible pad layer; 5. Integrated data acquisition unit; 51. Fastening cover plate. Detailed Implementation

[0029] To enable those skilled in the art to better understand the technical solutions of this application, the technical solutions of this application will be further described below in conjunction with the accompanying drawings and embodiments.

[0030] In the description of this application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "front end", "rear end", "inner side", "outer side", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0031] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0032] Example 1 Reference Figures 1 to 5 A thin-film sensor measurement module for heavy-duty pressure measurement includes a rigid base layer 1, a first flexible pad layer 2, a thin-film pressure sensor 3, a second flexible pad layer 4, and an integrated data acquisition unit 5.

[0033] The rigid base layer 1 is made of high-strength aluminum alloy material, such as aluminum alloy sheet of grade 6105, with a thickness of 0.8 cm and a density of approximately 2.8 g / cm³. The overall dimensions of the rigid base layer 1 are 90 cm in length and 70 cm in width. The opposite two edges of the rigid base layer 1 are respectively machined with a gradually decreasing slope transition structure. The material within a 20 cm length of each edge is milled into a slope, so that the edge thickness gradually decreases from 0.8 cm to near zero.

[0034] The first flexible pad 2 is disposed on the rigid base layer 1, and its lower surface is bonded and fixed to the upper surface of the rigid base layer 1 by an adhesive layer 33. The first flexible pad 2 is made of silicone material and has a thickness of 0.2 cm. The first flexible pad 2 forms a transition buffer layer between the rigid base layer 1 and the thin-film pressure sensor 3, avoiding local stress concentration caused by direct contact between the lower surface of the sensor and the rigid base layer 1. The lower surface of the first flexible pad 2 is fully and firmly bonded to the rigid base layer 1.

[0035] A thin-film pressure sensor 3 is disposed on the first flexible pad 2. The thin-film pressure sensor 3 is an array-type flexible piezoresistive pressure sensor with an effective measurement size of 520 mm × 640 mm and a thickness of approximately 0.6 mm. The thin-film pressure sensor 3 has an effective sensing area 31 and a non-sensing area 32 surrounding the effective sensing area 31. An array of pressure-sensitive units is arranged within the effective sensing area 31 for sensing and acquiring pressure distribution information; the non-sensing area 32 is the edge region surrounding the effective sensing area 31 that does not contain pressure-sensitive units, and it is provided with leads and connecting lines. An adhesive layer 33 is provided in the non-sensing area 32 for bonding to the upper surface of the first flexible pad 2 and the lower surface of the second flexible pad 4. The effective sensing area 31 is bonded to the second flexible pad 4 and the first flexible pad 2 without adhesive, and neither the upper nor lower surface of the effective sensing area 31 is in direct contact with the adhesive. The adhesive layer 33 of the non-sensing area 32 is made of low-tack pressure-sensitive adhesive, which has sufficient adhesive force to prevent relative slippage between the thin-film pressure sensor 3 and the upper and lower flexible pads under heavy rolling pressure; and allows the thin-film pressure sensor 3 to be horizontally pulled out smoothly over the adhesive force after supporting the extended first flexible pad 2 and the second flexible pad 4.

[0036] The second flexible pad 4 is disposed on the thin-film pressure sensor 3, located on the pressure-receiving side of the thin-film pressure sensor 3. The second flexible pad 4 is made of silicone material with a thickness of 0.5 cm, while the first flexible pad 2 has a thickness of 0.2 cm, with a thickness ratio of 2.5:1. The edges of the second flexible pad 4 and the first flexible pad 2 are fixedly connected, forming a closed edge structure surrounding the thin-film pressure sensor 3. A lateral opening is reserved on one side of the area where the edges of the second flexible pad 4 and the first flexible pad 2 are connected, and the thin-film pressure sensor 3 is inserted between the first flexible pad 2 and the second flexible pad 4 through this lateral opening. One end of the lead-out end of the thin-film pressure sensor 3 extends outward through the lateral opening. The static friction coefficient between the second flexible pad 4 and the tire rubber is not less than 0.9.

[0037] The integrated data acquisition unit 5 is located at the end edge of the rigid base layer 1, on one side of the extension direction of the lead-out end of the thin-film pressure sensor 3. The integrated data acquisition unit 5 is equipped with a removable fastening cover 51, which is mounted to the housing of the integrated data acquisition unit 5 by screws or clips. The lead-out end of the thin-film pressure sensor 3 extends below the fastening cover 51. When the fastening cover 51 is closed, it presses down on the lead-out end, keeping it in contact with the electrical contacts inside the integrated data acquisition unit 5, while simultaneously restricting the displacement of the thin-film pressure sensor 3. When the fastening cover 51 is opened, the clamping force of the electrical contacts is released, allowing the thin-film pressure sensor 3 to be laterally pulled out from between the first flexible pad 2 and the second flexible pad 4. The opening and closing of the fastening cover 51 does not affect the edge connection between the first flexible pad 2 and the second flexible pad 4.

[0038] A transverse sliding groove 11 is provided at the bottom of the rigid base layer 1. The transverse sliding groove 11 extends along the width direction of the rigid base layer 1 and cooperates with the fixing bolt column on the test bench floor, so that the measuring module can slide laterally to adjust the installation position and be locked by fasteners.

[0039] Technical principle: This application adopts a bottom-up multi-layer composite support structure. Through the stiffness gradient of each layer of material and selective bonding design, it can simultaneously achieve sensor protection, measurement accuracy maintenance and convenient replacement under heavy tire rolling conditions.

[0040] The rigid base layer 1 provides the overall foundational load-bearing stiffness, ensuring the measurement module remains stable under heavy loads. A first flexible pad layer 2 is positioned between the rigid base layer 1 and the thin-film pressure sensor 3, forming a transition buffer. This distributes the supporting force transmitted by the rigid base layer 1 evenly across the lower surface of the sensor, preventing localized stress concentration caused by hard contact between the sensor and the rigid base layer 1. A second flexible pad layer 4, located on the pressure-bearing side of the sensor and thicker than the first flexible pad layer 2, forms the primary mechanical buffer space between the tire and the sensor, absorbing and attenuating the peak value of the impact load. The edges of the second flexible pad layer 4 and the first flexible pad layer 2 are fixedly connected, forming a closed edge structure surrounding the sensor, with a lateral opening reserved on the opposite side of the sensor lead-out end.

[0041] An adhesive layer 33 is provided in the non-sensing area 32 to clamp and fix the thin-film pressure sensor 3 between the first flexible pad 2 and the second flexible pad 4, preventing the sensor from slipping under heavy load and tire shear force. The effective sensing area 31 has no adhesive on either side; the adhesive layer does not cover or penetrate the sensing area, eliminating interference from differences in the elastic modulus of the adhesive layers on pressure transmission, allowing pressure to be directly transmitted from the second flexible pad 4 to the sensor sensing area. The adhesive layer 33 in the non-sensing area 32 uses a low-tack pressure-sensitive adhesive with sufficient adhesion to resist the shear force generated by tire rolling, preventing sensor slippage, while not forming a high-strength bond, allowing the sensor to slide smoothly out when horizontally removed.

[0042] The integrated data acquisition unit 5 is located at the end edge of the rigid base layer 1, and the lead-out end of the thin-film pressure sensor 3 extends into the integrated data acquisition unit 5 through a lateral opening. The integrated data acquisition unit 5 is equipped with a removable fastening cover 51. When the fastening cover 51 is closed, it presses the lead-out end to achieve electrical connection and restrict sensor displacement; when opened, it releases the clamping force, and the sensor can be pulled out laterally from the lateral opening. The edge connection structure between the second flexible pad 4 and the first flexible pad 2 remains in place after the sensor is pulled out. When a new sensor is reinstalled, the edge connection provides a positioning reference, and the lateral opening and the flexible extension of the upper and lower pads provide an insertion channel without disassembling the fixing structure between the upper and lower flexible pads and the rigid base layer 1.

[0043] In summary, this application utilizes a rigid base layer 1 for support, a double-layer flexible pad for graded buffering, a low-adhesion adhesive fixation for the non-sensing area 32, a glue-free direct pressure transmission for the effective sensing area 31, a bag-shaped encapsulation structure with a side opening at the edge connection, and an integrated data acquisition unit 5 with a detachable fastening cover plate 51. Under heavy-duty tire crushing conditions, this protects the sensor from impact damage, eliminates pressure transmission interference from the adhesive layer to the sensing area, and enables the sensor to be quickly removed and installed from the side opening.

[0044] Example 2 like Figure 6 and Figure 7 As shown, based on Embodiment 1, in Embodiment 2, the transverse slide groove 11 is set to a "T" shaped cross section, which directly limits the vertical direction through the structure, without the need for additional limiting methods, thereby improving the stability of the measurement module in the vertical direction.

[0045] Example 3 This embodiment provides a method for assembling the measurement module of Embodiment 1 or 2, which is carried out according to the following steps: Step 1: Bond and fix the lower surface of the first flexible pad 2 to the upper surface of the rigid base layer 1 to form the bottom support platform.

[0046] Step 2: Place the thin-film pressure sensor 3 on the first flexible pad 2, aligning the effective sensing area 31 with the adhesive-free area on the upper surface of the first flexible pad 2, and aligning the non-sensing area 32 with the adhesive-coated area on the upper surface of the first flexible pad 2. During placement, ensure that the lead-out end of the thin-film pressure sensor 3 faces the mounting direction of the integrated data acquisition unit 5.

[0047] Step 3: Cover the thin-film pressure sensor 3 with the second flexible pad 4, aligning the adhesive-free area on the lower surface of the second flexible pad 4 with the effective sensing area 31, and the non-sensing area 32 with the adhesive layer 33 on the upper surface of the first flexible pad 2. Through the clamping action of the upper and lower adhesive layers 33, the thin-film pressure sensor 3 is fixed between the first flexible pad 2 and the second flexible pad 4, while both the upper and lower surfaces of the effective sensing area 31 are in an adhesive-free bonding state.

[0048] Step 4: Fix the edge of the second flexible pad 4 to the edge of the first flexible pad 2. When fixing, make a full circumferential connection on the opposite edge of the lead-out end of the thin film pressure sensor 3, and leave a lateral opening on one side of the lead-out end so that the lead-out end of the thin film pressure sensor 3 extends to the outside of the first flexible pad 2 and the second flexible pad 4 through the lateral opening.

[0049] Step 5: Insert the lead-out end of the thin-film pressure sensor 3 into the integrated data acquisition unit 5, so that the contact of the lead-out end forms an elastic electrical contact with the conductive pin inside the integrated data acquisition unit 5. Then install the fastening cover plate 51 to press the lead-out end and restrict the displacement of the thin-film pressure sensor 3.

[0050] The assembly process proceeds in a bottom-up, layer-by-layer stacking sequence, with final edge sealing. First, the first flexible pad 2 is fixed to form a reference plane. Then, the sensor is placed and aligned with the adhesive-free area. Next, the second flexible pad 4 is covered and secured using the non-sensing area 32 and adhesive layer 33. The edges of the two flexible pads are then fixedly connected to form a bag-like structure surrounding the sensor, with a lateral opening. Finally, the lead-out end is connected to the integrated data acquisition unit 5, and the cover plate 51 is locked securely. This layered approach, with clear positioning requirements, reduces assembly alignment difficulty and minimizes the risk of overlap between the sensing area and the adhesive layer.

[0051] When the sensor needs to be replaced, open the fastening cover 51 to release the clamping force, pull out the old sensor laterally, push the new sensor in from the side opening, align it with the glue-free area, and then close the fastening cover 51. There is no need to disassemble the fixing structure between the first flexible pad 2 and the second flexible pad 4 and the rigid base layer 1.

[0052] Example 4 This embodiment provides a modified implementation where the thickness ratio of the second flexible pad 4 to the first flexible pad 2 is 3:1. In this embodiment, the thickness of the second flexible pad 4 can be set to 0.6 cm, and the thickness of the first flexible pad 2 can be set to 0.2 cm, resulting in a thickness ratio of 3:1 between the second flexible pad 4 and the first flexible pad 2.

[0053] At this ratio, the upper pressure layer has a relatively larger buffer thickness. When a heavy-duty vehicle passes over the measurement module at a high speed, the thicker second flexible pad 4 can provide a greater elastic compression stroke, helping to absorb stronger instantaneous impact energy and attenuating the peak impact load to some extent. This implementation is suitable for measurement scenarios where heavy-duty vehicles frequently run over the vehicle and the impact load is large. It should be noted that when the thickness of the second flexible pad 4 is further increased, although the buffering performance can be improved to some extent, it may lead to an excessively large total thickness above the sensor, which lengthens the pressure transmission path between the tire and the effective sensing area 31 of the sensor, potentially introducing additional elastic deformation errors and affecting the accuracy of pressure measurement. Therefore, controlling the thickness ratio within 3:1 helps to maintain a reasonable balance between buffering performance and measurement accuracy.

[0054] Example 5 This embodiment provides a modified implementation where the thickness ratio of the second flexible pad 4 to the first flexible pad 2 is 2:1. In this embodiment, the thickness of the second flexible pad 4 can be set to 0.4 cm, and the thickness of the first flexible pad 2 can be set to 0.2 cm, resulting in a thickness ratio of 2:1.

[0055] At this ratio, the thickness difference between the upper and lower flexible pads is relatively small, and the second flexible pad 4 can still provide necessary cushioning protection on the pressure side. Simultaneously, due to the small total thickness, the overall thickness of the measuring module can be controlled within a relatively thin range, helping to reduce the step height when the tire enters the measuring module. This implementation is suitable for measurement scenarios with limited installation space, relatively low rolling speeds, and moderate impact loads. It should be noted that the thickness of the second flexible pad 4 should not be less than 0.4 cm to ensure that the effective sensing area 31 does not directly bear rigid local high pressure when a heavy-load tire rolls over it, maintaining the necessary cushioning protection effect.

[0056] Example 6 This embodiment details the arrangement of the adhesive layer 33 and its manufacturing process.

[0057] In one specific embodiment, the adhesive layer 33 may be made of pressure-sensitive adhesive material, such as 3M adhesive backing.

[0058] The upper surface of the first flexible pad 2 is covered with an adhesive layer 33 in the area corresponding to the non-sensing area 32, while no adhesive layer 33 is provided in the area corresponding to the effective sensing area 31, forming a glue-free area. The lower surface of the second flexible pad 4 is covered with an adhesive layer 33 in the area corresponding to the non-sensing area 32, while no adhesive layer 33 is provided in the area corresponding to the effective sensing area 31, forming a glue-free area.

[0059] The non-sensing area 32 of the thin-film pressure sensor 3 is bonded and fixed to the first flexible pad 2 and the second flexible pad 4 on both the upper and lower surfaces through adhesive layers 33, thereby clamping and fixing the thin-film pressure sensor 3 between the two flexible pads. The effective sensing area 31 is in direct contact with the adhesive-free areas of the first flexible pad 2 and the second flexible pad 4 on both the upper and lower surfaces, forming an adhesive-free bonding state.

[0060] Process implementation method: The above selective bonding arrangement can be achieved through the following process: Select silicone pad raw materials with built-in 3M adhesive (such as Sanyou Chemical SY-GJMF type silicone pads). After cutting the raw materials to the required size, use die-cutting or laser cutting processes to remove the adhesive corresponding to the effective sensing area 31, retaining the adhesive in the non-sensing area 32. For die-cutting, a die matching the shape of the effective sensing area 31 can be used; for laser cutting, a CO2 laser cutting machine can be used to precisely remove the adhesive area corresponding to the sensing area according to a preset coordinate trajectory, with cutting accuracy controlled within ±0.5 mm. The surface of the adhesive-free area after removing the adhesive should be clean, flat, and free of residual adhesive.

[0061] First, the lower surface of the first flexible pad 2 is adhered and fixed to the upper surface of the rigid base layer 1. Then, the thin-film pressure sensor 3 is placed on the first flexible pad 2, aligning and adhering the non-sensing area 32 with the adhesive area. Finally, the second flexible pad 4 (after removing the adhesive backing from the non-adhesive area on its lower surface) is placed over the sensor, aligning and adhering the non-sensing area 32 with the adhesive area, thus completing the clamping and fixing process. This process helps ensure that the adhesive does not penetrate into the effective sensing area 31, avoiding interference with pressure transmission due to uneven adhesive layer thickness or differences in elastic modulus.

[0062] Example 7 This embodiment illustrates a quick replacement method for the thin-film pressure sensor 3.

[0063] When the thin-film pressure sensor 3 needs to be replaced due to performance degradation or damage after long-term use, the following steps can be followed without disassembling the adhesive fixing structure between the first flexible pad 2, the second flexible pad 4 and the rigid base layer 1: Step 1: Loosen the fixing screws of the fastening cover plate 51 on the integrated data acquisition unit 5 (or release the snap-fit ​​connection) and remove the fastening cover plate 51 from the housing of the integrated data acquisition unit 5. At this time, the clamping force of the conductive pin on the lead-out end of the thin film pressure sensor 3 is released, the electrical contact between the lead-out end and the conductive pin is broken, and the limiting constraint of the positioning sleeve hole on the end of the sensor is released.

[0064] Step 2: Hold the end of the thin-film pressure sensor 3 (lead-out side) and pull the thin-film pressure sensor 3 out from between the first flexible pad 2 and the second flexible pad 4 in a horizontal direction (lateral direction) (during this process, the distance between the first flexible pad 2 and the second flexible pad 4 can be appropriately increased, especially at the corresponding position of the adhesive layer 33). The sensor can be pulled out smoothly.

[0065] Step 3: Take the new thin-film pressure sensor 3, align its end positioning structure with the positioning sleeve hole of the integrated data acquisition unit 5, and push the new thin-film pressure sensor 3 horizontally between the first flexible pad 2 and the second flexible pad 4, so that the effective sensing area 31 is aligned with the adhesive-free area of ​​the upper and lower flexible pads (similarly, the distance between the first flexible pad 2 and the second flexible pad 4 can be appropriately increased during this process, especially at the corresponding position of the adhesive layer 33, to reduce resistance), while the contact point of the lead-out end forms elastic contact with the conductive pin. During the pushing process, care should be taken to keep the sensor flat and avoid folding or twisting.

[0066] Step 4: Reinstall and secure the fastening cover 51 onto the housing of the integrated data acquisition unit 5, ensuring reliable elastic electrical contact between the conductive pin and the lead-out end. Simultaneously, press the fastening cover 51 against the sensor end from above, engaging with the positioning sleeve hole to limit sensor displacement. The sensor replacement is now complete.

[0067] This replacement method does not require disassembling the adhesive structure between the bottom first flexible pad 2 and the rigid base layer 1, nor does it require removing the upper second flexible pad 4. The operation is relatively convenient, which shortens the maintenance time to a certain extent and reduces the impact on surrounding components.

[0068] Example 8 This embodiment illustrates the on-site installation and position adjustment method of the measurement module.

[0069] In one on-site installation embodiment, the transverse sliding groove 11 at the bottom of the rigid base layer 1 can be installed in conjunction with the fixing bolt post on the test chamber floor. During installation, the head of the fixing bolt post is inserted into the transverse sliding groove 11, allowing the measuring module to slide horizontally along the transverse sliding groove 11 to adjust the lateral position of the measuring module. When the axle spacing of the vehicle is different, the left and right wheels can be aligned with the effective sensing area 31 of the corresponding measuring module by sliding the measuring module.

[0070] After the position is adjusted, use flat-head screws or other fasteners to tighten them through the slots of the transverse slide groove 11 and the fixing bolts to lock the measuring module in the current position. During the measurement process, the cooperation between the fixing bolts and the transverse slide groove 11 can restrain the displacement of the measuring module in the horizontal direction, while providing load-bearing support in the vertical direction, ensuring that the measuring module remains stable under heavy tire pressure.

[0071] When the measuring module needs to be disassembled, simply loosen the fasteners, and the measuring module will slide out along the transverse slide groove 11, freeing itself from the constraint of the fixing bolt column, thus completing the disassembly. This installation method helps to adapt to different wheel spacings of different wheeled vehicles, and to a certain extent improves the versatility and position adjustment convenience of the measuring module.

[0072] Example 9 This embodiment illustrates the calibration method for the measurement module.

[0073] To ensure the measurement accuracy of the thin-film pressure sensor, it should be calibrated after the measurement module is assembled and before formal use. Calibration can be performed using a multi-point calibration method, and the specific steps are as follows: Step 1: Preparation Place the assembled measurement module on a horizontal reference surface, ensuring the bottom surface of the rigid base layer is stably fitted. Connect the integrated acquisition unit to the data acquisition system and confirm normal signal transmission. Place a standard loading plate (e.g., a rigid plate with an area not smaller than the effective sensing area) above the effective sensing area to ensure uniform distribution of the loading pressure.

[0074] Step 2: Multi-point pressurization and data acquisition Multiple known standard pressure values ​​are applied sequentially over the effective sensing area. For example, at least five calibration points are uniformly selected within the 0–2068 kPa range (e.g., 0 kPa, 500 kPa, 1000 kPa, 1500 kPa, 2068 kPa). A stable pressure is maintained at each calibration point, and the sensor output signal value (voltage value or digital value) corresponding to each calibration point is acquired using an integrated data acquisition unit. Each calibration point is measured at least three times, and the average value is taken as the standard output value for that point.

[0075] Step 3: Generate calibration curve A pressure-signal correspondence is established by plotting the standard pressure value on the x-axis and the sensor output signal value on the y-axis. Based on the collected data, the following fitting methods can be selected to generate the calibration curve: Linear fitting: Suitable for scenarios where the sensor output and pressure have an approximately linear relationship across the entire range. The least squares method is used to fit the linear function calibration curve. Piecewise linear fitting: The measurement range is divided into multiple intervals, and linear fitting is performed in each interval. This method is suitable for sensors with high nonlinearity. Quadratic fitting: Employs a polynomial fitting method, supporting up to nine calibration points to generate a quadratic curve, suitable for sensors with significant nonlinear characteristics.

[0076] Step 4: Save and Verify The calibration coefficients are saved in the data acquisition device's configuration file. After calibration, verification can be performed by loading standard weights or using a pressure testing machine. The calibrated measured values ​​are compared with the standard values ​​at several verification points to confirm that the measurement error is within the ±5% range.

[0077] Sensitivity adjustment: During calibration, the sensor can be brought into operation within the linear range by adjusting the system sensitivity. Sensitivity adjustment is divided into coarse adjustment (range 0~7) and fine adjustment (range 0~255), which essentially involves linearly adjusting the amplification gain of the acquired analog voltage value. The principle of sensitivity adjustment is: when the maximum calibration pressure is applied, the output response of the effective sensing area should exhibit as little or no saturation color (purple) as possible, thus ensuring that the thin-film pressure sensor operates within the linear range.

[0078] This calibration process helps eliminate systematic errors caused by factors such as the thickness of the flexible pad, individual sensor variations, and assembly conditions, thereby improving the accuracy of pressure measurements. The calibration file can be exported and saved, and can be directly imported during subsequent recalibration, avoiding repetitive operations.

[0079] Example 10 This embodiment provides a performance verification test method to verify the structural integrity and pressure measurement accuracy of the above-mentioned measurement module under heavy-load rolling conditions.

[0080] (1) Test equipment and environment Test device: Floor pressure dynamic measurement device, whose measurement module has the same structure as described in Example 1, including a rigid base layer (6105 aluminum alloy, 0.8 cm thick), a first flexible pad layer (silicone pad, 0.2 cm thick), a thin film pressure sensor (effective measurement size 520 mm × 640 mm, range 0~300 psi), a second flexible pad layer (silicone pad, 0.5 cm thick, static friction coefficient with tire rubber 0.9) and an integrated data acquisition unit.

[0081] Test vehicle: A XE480WGM wheeled excavator from a certain group. Measured on a level road weighbridge, its front axle load was 23.17 t (1# wheel 11670 kg + 4# wheel 11500 kg), and its rear axle load was 24.48 t (2# wheel 12460 kg + 3# wheel 12020 kg). The total vehicle weight was approximately 48 t, both exceeding the design requirement of 15 t.

[0082] Test environment: ambient temperature 25 ℃, ambient humidity 47%RH.

[0083] (2) Slope compaction test Test site: Test slope of the excavator division of a certain group. The measured slope is 14°, which is greater than the test requirement of 11°.

[0084] Installation method: First, fix the supporting iron plate to the slope platform with welding screws to serve as the base platform; then, fit the slider on the bottom plate of the measuring module into the round hole of the supporting iron plate to reliably fix the measuring module to the slope platform.

[0085] Experimental procedure: 1. Forward driving test: Start the wheeled excavator and drive its right front wheel forward from the bottom of the slope, running over the measurement module. After a brief stop on the measurement module, start it again and drive away from the measurement module. 2. Reverse driving test: The wheeled excavator reverses at the top of the slope, so that the right rear wheel runs over the measuring module. After a brief stop on the measuring module, it starts again and reverses to the bottom of the slope. 3. The vehicle is run over repeatedly during the forward and reverse driving processes described above.

[0086] Test results: After repeated rolling, the measuring module showed no obvious deformation, the protective silicone layer on the surface was undamaged and did not bulge, the system worked normally and met the structural integrity requirements.

[0087] Accuracy verification test of ground pressure measurement After the slope compaction test, the measuring module was laid flat on the horizontal road surface to verify the pressure measurement accuracy of the same wheeled excavator.

[0088] Measurement method: The weights of the right front wheel and right rear wheel of the wheeled excavator were measured using a measurement module and a weighbridge (as a standard reference).

[0089] The measurement results are shown in Table 1: Table 1 Measurement results of slope compaction test

[0090] Error Analysis: The error between the total weight of the front and rear wheels measured by the measurement module and the total weight of the weighbridge is +3%, which is within the ±5% accuracy range and meets the test requirements. It should be noted that during the planar test, the forward movement of the wheeled excavator's large pendulum caused a shift in the vehicle's center of gravity, resulting in the measurement module measuring a greater weight on the front wheels than on the rear wheels. This trend is opposite to the single-wheel measurement results of the weighbridge. However, the combined weight of the front and rear wheels is not affected by the center of gravity shift; therefore, the total weight is used for error analysis.

[0091] (3) Verification of pressure distribution measurement function After the rolling test, the pressure distribution measurement function of the measurement module was normal. The data analysis software can display the tire contact marks and pressure distribution in real time, including two-dimensional smooth images, two-dimensional block images and three-dimensional surface modes. It can dynamically measure pressure, contact area, pressure distribution and pressure data, and supports peak display and center of gravity tracking functions.

[0092] (4) Experimental conclusions The above performance verification tests show that the measurement module described in this application remains structurally intact, with no surface bulges or damage, and functions normally under the condition of being repeatedly rolled over by heavy-duty vehicles with axle loads exceeding 20 t. The pressure measurement error is controlled within ±5%, meeting the design requirements.

[0093] The foregoing has shown and described the basic principles, main features, and advantages of this application. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this application. Various changes and modifications can be made to this application without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of this application as claimed. The scope of protection of this application is defined by the appended claims and their equivalents.

Claims

1. A thin-film sensor measurement module for heavy-duty pressure measurement, characterized in that, include: Rigid base layer (1); A first flexible pad (2) is disposed on the rigid base layer (1), and the lower surface of the first flexible pad (2) is fixedly attached to the rigid base layer (1); A thin-film pressure sensor (3) is disposed on the first flexible pad (2). The thin-film pressure sensor (3) has an effective sensing area (31) and a non-sensing area (32) surrounding the effective sensing area (31). A second flexible pad (4) is disposed on the thin film pressure sensor (3). The second flexible pad (4) is connected to the edge of the first flexible pad (2), and there is a lateral opening between the second flexible pad (4) and the first flexible pad (2) for inserting and removing the thin film pressure sensor (3). An integrated data acquisition unit (5) is disposed at the end edge of the rigid base layer. The integrated data acquisition unit is equipped with a removable fastening cover plate (51), and one side of the thin film pressure sensor (3) extends into the fastening cover plate (51) through the lateral opening. The non-sensing area (32) is provided with an adhesive layer (33) between it and the first flexible pad (2) and the second flexible pad (4), and the effective sensing area (31) is bonded to the second flexible pad (4) and the first flexible pad (2) without adhesive; the fastening cover plate (51) is configured such that when opened, the thin film pressure sensor (3) can be pulled out from between the first flexible pad (2) and the second flexible pad (4); The thickness ratio of the second flexible pad (4) to the first flexible pad (2) is 2:1 to 3:1; The rigid base layer (1) is made of aluminum alloy, and the opposite two sides of the rigid base layer (1) are respectively provided with a slope transition structure with gradually decreasing thickness. The bottom of the rigid base layer (1) is provided with a transverse slide groove (11).

2. The measurement module according to claim 1, characterized in that, The thickness of the second flexible pad (4) is 0.4 cm to 0.6 cm, and the thickness of the first flexible pad (2) is 0.15 cm to 0.25 cm.

3. The measurement module according to claim 1, characterized in that, The second flexible pad (4) is made of silicone material and is configured to have a static friction coefficient with tire rubber of not less than 0.

9.

4. The assembly method of the measurement module as described in any one of claims 1 to 3, characterized in that, Includes the following steps: The lower surface of the first flexible pad (2) is fixedly connected to the rigid base layer (1); Place the thin-film pressure sensor (3) on the first flexible pad (2) so that the effective sensing area (31) is aligned with the glue-free area on the upper surface of the first flexible pad (2); The second flexible pad (4) is covered on the thin film pressure sensor (3), so that the glue-free area on the lower surface of the second flexible pad (4) is aligned with the effective sensing area (31), and the thin film pressure sensor (3) is clamped and fixed between the first flexible pad (2) and the second flexible pad (4) through the adhesive layer (33), and both the upper and lower surfaces of the effective sensing area (31) are in a glue-free bonding state; The second flexible pad (4) is fixedly connected to the edge of the first flexible pad (2), and a lateral opening is reserved for the insertion and removal of the thin film pressure sensor (3); The thin-film pressure sensor (3) is extended to the area outside the first flexible pad (2) and the second flexible pad (4), connected to the integrated acquisition unit (5), and the fastening cover plate (51) is installed.

Images