Six-dimensional force sensor double-barrier sealing structure and design method thereof

Abstract

The invention discloses a six-dimensional force sensor double-barrier sealing structure and a design method thereof, and belongs to the technical field of sensors. An elastic element is clamped between an upper cover plate and the elastic element, the upper cover plate is provided with a step structure extending towards the elastic element, and an annular gap is formed; the customized rubber mat is filled in the annular gap, and the lower surface of the customized rubber mat covers an annular area surrounding the strain beam in the upper surface of the elastic element to form a first plane sealing barrier; annular grooves are formed in the upper surface and the lower surface of the elastic element, and the O-shaped rings are arranged in the annular grooves; when the upper cover plate and the lower cover plate are fastened through the locking piece, the O-shaped ring is extruded to deform and is tightly attached to the inner surface of the upper cover plate or the lower cover plate and the wall face of the annular groove, and a second radial sealing barrier is formed. The problems that an existing six-dimensional force sensor is insufficient in sealing performance and difficult to maintain in a liquid erosion environment are solved, and the six-dimensional force sensor has the advantages of composite sealing, modular assembly and the like.

Description

Technical Field

[0001] This invention relates to a double-barrier sealing structure for a six-dimensional force sensor and its design method, belonging to the field of sensor technology. Background Technology

[0002] Six-dimensional force sensors are key sensing components in fields such as robotics, precision assembly, and polishing. They often face the risk of corrosion from coolants, lubricants, or other industrial liquids during the design process, making the reliability of their sealing structure crucial.

[0003] Numerous research institutions and enterprises are dedicated to improving the sealing performance of six-dimensional force sensors. For example, Chinese patent CN222719083U discloses a sealing structure for a six-dimensional force sensor, which uses a multi-layer combination of upper and lower sealing rings plus a dustproof sealing ring, providing a better sealing effect and helping to extend its service life. Chinese patent CN118641095A, under the action of a balancing membrane, can make the oil pressure inside the sealed space tend to be balanced with the pressure of the external seawater, thus effectively avoiding damage to the sensor caused by the high pressure in deep ocean water. Chinese patent CN119394495A proposes a waterproof solution with a snap-fit ​​structure, which improves the ease of disassembly and assembly of the top cover and the sensor body through springs and right-angled trapezoidal telescopic blocks.

[0004] While the aforementioned technologies each have their own characteristics, they still have significant limitations. First, most designs focus on a single sealing method, such as relying solely on O-ring radial sealing or sealant / film, lacking multi-level, mutually redundant sealing mechanisms. If a single sealing point fails, the overall protection will fail. Second, some sealing structures may interfere with the sensitive measurement area of ​​the elastic element during assembly or under stress, affecting the force transmission path and measurement accuracy of the sensor. Finally, some effective sealing solutions (tube potting sealant) are extremely inconvenient to maintain, often requiring destructive disassembly or complete replacement, resulting in high maintenance costs and long maintenance cycles.

[0005] Therefore, there is an urgent need to propose a six-dimensional force sensor double-barrier sealing structure and its design method to solve the above-mentioned technical problems. Summary of the Invention

[0006] The purpose of this invention is to address the problems of insufficient sealing performance and difficult maintenance of existing six-dimensional force sensors in liquid corrosive environments, while possessing advantages such as composite sealing and modular assembly. A brief overview of the invention is provided below to offer a basic understanding of certain aspects thereof. It should be understood that this overview is not an exhaustive summary of the invention. It is not intended to identify key or essential parts of the invention, nor is it intended to limit the scope of the invention.

[0007] The technical solution of this invention:

[0008] Option 1: A six-dimensional force sensor double-barrier sealing structure, comprising an upper cover plate, an elastic element, a lower cover plate, a custom-made rubber gasket, and an O-ring. The elastic element is clamped between the upper cover plate and the elastic element. The upper cover plate has a stepped structure extending toward the elastic element, thereby forming an annular gap between the upper cover plate and the load-bearing frustum of the elastic element.

[0009] A custom-made adhesive pad is filled within the annular gap, and its lower surface covers the annular area surrounding the strain beam on the upper surface of the elastic element, forming the first planar sealing barrier.

[0010] Both the upper and lower surfaces of the elastic element are provided with annular grooves, and an O-ring is disposed in the annular grooves.

[0011] When the upper cover plate and the lower cover plate are fastened by the locking member, the O-ring is compressed and deformed, and fits tightly against the inner surface of the upper cover plate or the lower cover plate and the wall of the annular groove, forming a second radial sealing barrier.

[0012] Preferably, the outer periphery of the load-bearing frustum of the elastic element is provided with an annular protective groove;

[0013] The lower surface of the custom-made adhesive pad has a downwardly protruding L-shaped structure that extends into the annular protective groove, and there is a predetermined gap between its outer contour and the inner wall of the annular protective groove for filling with sealant.

[0014] Preferably, the upper surface of the customized rubber pad has a stepped protrusion, which is adapted to the stepped structure of the upper cover plate, and the fitting gap between the two is no more than 0.1mm.

[0015] Preferably, the custom rubber pad is pre-fixed to the upper surface of the elastic element by silicone rubber adhesive, and is fastened to the upper cover plate by outer ring screws and inner ring screws that penetrate through the pad; the outer ring screws and inner ring screws of the pad have guide chamfers at the edges of the holes through the custom rubber pad.

[0016] Preferably, the compression ratio of the O-ring in the assembled state is designed to be 15% to 25%.

[0017] Preferably, the inner wall of the annular groove of the elastic element is provided with micro-textures to increase adhesion.

[0018] Preferably, the Shore hardness of the custom-made rubber pad is 35±5.

[0019] Option 2: A design method for the six-dimensional force sensor double-barrier sealing structure described in Option 1, comprising the following steps:

[0020] S1. Determine the stiffness of the elastic element and the sealing barrier scheme:

[0021] The equivalent stiffness K of the strain beam of the elastic element in the measurement direction is obtained. s ;

[0022] A dual-barrier sealing solution was determined, using custom-made rubber gaskets for planar sealing and O-rings for radial sealing;

[0023] S2. Design and customize the hardness and structure of the rubber pad:

[0024] The equivalent stiffness K of the elastic element strain beam in the measurement direction s The customized rubber pad, compressed in the same direction by the pre-tightening force of the top cover plate, has an equivalent stiffness of K. g To ensure that the custom-made rubber pads do not negate the loads that should be sensed by the strain beam, the following conditions must be met:

[0025] K g < <K s

[0026] Typically, when K is satisfied g ≤0.01K s At this time, the impact of the custom rubber pad on the overall stiffness and measurement accuracy of the sensor is negligible. Considering that the custom rubber pad is mainly in a compressed state, its compressive stiffness K g It can be approximately estimated using the following formula:

[0027]

[0028] Among them, E g t is the compressive elastic modulus of the rubber pad material, A is the effective bearing area of ​​the rubber pad, and t is the thickness of the rubber pad.

[0029] Based on the empirical relationship model between Eg and Shore hardness HS, the Shore hardness of the customized rubber pad is calculated and selected to ensure that its stiffness does not affect the measurement accuracy of the sensor.

[0030] The structure of the custom rubber pad is designed such that its upper surface forms a protrusion that matches the stepped structure of the upper cover plate, and its lower surface forms an L-shaped structure that can extend into the annular protective groove of the elastic element.

[0031] S3. Design the sealing parameters of the O-ring:

[0032] Select the cross-sectional diameter of the O-ring based on the size of the annular groove on the elastic element;

[0033] Set the compression rate of the O-ring to 15% to 25%, and determine the depth of the annular groove accordingly;

[0034] S4. Assembly and Verification:

[0035] The custom-made rubber pad is pre-fixed to the elastic element using an adhesive.

[0036] Install the O-ring into the annular groove;

[0037] The upper cover plate, the elastic element equipped with the custom rubber gasket and O-ring, and the lower cover plate are fastened together by locking components to form the double barrier sealing structure.

[0038] The present invention has the following beneficial effects:

[0039] 1. This invention does not simply increase the number of seals, but rather creates redundant protection through the synergistic design of the planar seal of the customized rubber gasket and the radial seal of the O-ring in both structure and function. The irregularly shaped structure of the rubber gasket is precisely calculated and designed to ensure that while filling the gap, it perfectly avoids the strain beam and the loaded frustum, fundamentally eliminating any impact on the mechanical properties of the measuring element. Furthermore, all components are modularly installed and can be independently disassembled; any damaged seal can be replaced individually without disassembling the core sensor structure, thus achieving a balance between sealing performance, measurement accuracy, and ease of maintenance.

[0040] 2. The dual-barrier sealing system consisting of the customized rubber gasket and O-ring of this invention provides redundant protection. Even if one barrier fails due to accidental micro-damage, the other barrier can still maintain an effective seal, greatly improving overall reliability;

[0041] 3. The invention has minimal impact on measurement accuracy: the flexible material of the custom-made rubber pad and the precisely designed boss and L-shaped structure allow it to perfectly fill the gap while avoiding rigid contact or interference with the sensitive strain beam and load-bearing frustum on the elastic element. This ensures that the mechanical transmission path of the sensor is not affected and guarantees measurement accuracy.

[0042] 4. This invention offers convenient maintenance and low cost: all components are modularly designed and secured with screws. Replacement is simple; only the corresponding screws need to be removed, requiring no specialized tools or damage to the sensor's overall structure. The maintenance process is quick and easy, significantly reducing time and economic costs. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the assembly state of a six-dimensional force sensor with a double-barrier sealed structure.

[0044] Figure 2 This is a schematic diagram of a six-dimensional force sensor with a double-barrier sealed structure.

[0045] Figure 3 This is a diagram showing the installation of the annular protective groove of the present invention.

[0046] Figure 4 This is a diagram showing the installation of the L-shaped downward protrusion structure on the upper cover plate of this invention.

[0047] Figure 5 This is a schematic diagram of the structure of the custom adhesive pad of the present invention.

[0048] In the diagram: 100 - Top cover plate; 101 - Stepped structure; 102 - Inner ring of stepped structure; 103 - Outer ring of top cover plate; 104 - L-shaped downward protrusion structure of top cover plate; 200 - Elastic element; 201 - Load-bearing frustum; 202 - Upper surface of elastic element; 203 - Lower surface of elastic element; 204 - Annular groove; 205 - Annular protective groove; 206 - Inner ring of elastic element; 207 - Outer ring of elastic element; 208 - Strain beam; 209 - Sealing wire hole; 300 - Lower cover plate; 400 - Custom rubber gasket; 401 - Upper surface of rubber gasket; 402 - Stepped boss; 403 - L-shaped structure; 404 - Annular groove of inner ring of rubber gasket; 500 - O-ring; 600 - Tightening screw of top cover plate. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0050] The connections mentioned in this invention are divided into fixed connections and detachable connections. Fixed connections (i.e., non-detachable connections) include, but are not limited to, conventional fixed connection methods such as folded connections, riveted connections, adhesive connections, and welded connections. Detachable connections include, but are not limited to, conventional disassembly methods such as threaded connections, snap-fit ​​connections, pin connections, and hinged connections. When a specific connection method is not explicitly defined, it is assumed that at least one existing connection method can always be found to achieve the function, and those skilled in the art can choose according to their needs. For example, a welded connection can be chosen for fixed connections, and a hinged connection can be chosen for detachable connections.

[0051] Specific implementation method one: Combining Figures 1-5This embodiment aims to address the problems of insufficient sealing reliability, maintenance difficulties, and interference with the mechanical properties of sensor measuring elements in liquid environments caused by existing sensors. This embodiment provides a six-dimensional force sensor with a double-barrier sealing structure, including an upper cover plate 100, an elastic element 200, a lower cover plate 300, a custom-made rubber gasket 400, and an O-ring 500. The elastic element 200 is clamped between the upper cover plate 100 and the lower cover plate 300. The upper cover plate 100 has a stepped structure 101 extending toward the elastic element 200, thereby forming an annular gap between the upper cover plate 100 and the load-bearing frustum 201 of the elastic element 200. The custom-made rubber gasket 400 fills the annular gap. Within the gap, and with its lower surface covering the annular area surrounding the strain beam 208 in the upper surface 202 of the elastic element 200, an O-ring 500 is formed, constituting the first planar sealing barrier. Both the upper surface 202 and the lower surface 203 of the elastic element have annular grooves 204, and an O-ring 500 is disposed within these grooves. When the upper cover plate 100 and the lower cover plate 300 are tightened by the upper cover plate tightening screws 600 and 600, the O-ring 500 is compressed and deformed, tightly adhering to the inner surface of the upper cover plate 100 or the lower cover plate 300 and the wall of the annular groove 204, forming the second radial sealing barrier. The lower surface of the custom-made rubber gasket 400 has a downwardly protruding L-shaped structure 403, which extends into the annular protective groove 205, and its outer contour has a predetermined gap for filling with sealant between it and the inner wall of the annular protective groove 205.

[0052] Specifically, the upper cover plate 100 and the lower cover plate 300 have an annular structure, with the elastic element 200 of the sensor installed between them. The stepped structure 101 of the upper cover plate 100 extends into the annular groove of the inner ring of the rubber pad to prevent liquid from entering from above and affecting the sensor measurement results.

[0053] The elastic element 200 has a load-bearing frustum 201 in the middle, and an annular protective groove 205 is provided around its periphery. The strain beam 208 of the elastic element 200 has a flat surface on both its inner and outer sides for placing a custom-made rubber pad 400. The elastic element 200 is fastened to the upper cover plate 100 and the lower cover plate 300 respectively by upper cover plate tightening screws 600 and lower cover plate tightening screws.

[0054] Furthermore, the outer periphery of the load-bearing frustum 201 of the elastic element 200 is provided with an annular protective groove 205; the lower surface 403 of the custom adhesive pad 400 has a downwardly protruding L-shaped structure 403, which extends into the annular protective groove 205, and there is a predetermined gap between its outer contour and the inner wall of the annular protective groove 205 for filling with sealant. This L-shaped structure 403 extends into the protective groove of the outer ring of the load-bearing frustum in the middle of the elastic element, with a certain gap between it and the protective groove, which is filled with protective sealant. Because its material is soft, it will not interfere with the elastic element 200, and at the same time, it can prevent liquid from entering the sensor from this point.

[0055] As another preferred embodiment, the upper surface 401 of the rubber pad has a stepped protrusion 402, which is adapted to the stepped structure 101 of the upper cover plate 100, and the fitting gap between the two is no greater than 0.1mm. The customized rubber pad is made of soft silicone rubber with a Shore hardness of 35±5. The upper surface 401 of the rubber pad is provided with a protrusion adapted to the stepped structure of the upper cover plate, and the lower surface 403 of the rubber pad has a cavity corresponding to the contour of the load-bearing frustum of the elastic body and the strain beam.

[0056] The customized rubber pad 400 is pre-fixed to the upper surface 202 of the elastic element 200 using silicone rubber adhesive, and is securely connected to the upper cover plate 100 by outer and inner ring screws penetrating through it. The edges of the holes through which the outer and inner ring screws pass through the customized rubber pad 400 are chamfered. Specifically, the rubber pad is pre-fixed to the upper surface of the elastomer using silicone rubber adhesive coated on the bottom. Each of its inner and outer rings has six through holes. Twelve screws press the rubber pad firmly between the elastomer and the upper cover plate, with chamfered edges at the screw penetration points to avoid interference. This installation method not only prevents the rubber pad from falling off, ensuring the sealing performance inside the sensor, but also allows for convenient maintenance or replacement of components through disassembly during later use.

[0057] In terms of core sealing parameter design, the compression rate of the O-ring 500 in the assembled state is designed to be 15% to 25%. Depending on the different sizes of the sensor, the elastic element annular groove 204 and the O-ring 500 will also be changed accordingly. However, it is unchanging that the groove depth of the annular groove must be 0.1~0.3mm larger than the O-ring diameter to ensure that the compression rate reaches 15%~25% after O-ring installation. Meanwhile, the Shore hardness of the custom rubber gasket 400 is 35±5.

[0058] The inner wall of the annular groove 204 of the elastic element 200 is provided with micro-textures to increase adhesion. These textures are used to increase the adhesion and contact area between the O-ring 500 and the groove wall, and when the O-ring is compressed, they can cooperate to form multiple sealing bands.

[0059] The elastic element 200 also has a sealed wire-through hole for the sealed exit of the sensor wire. The upper cover plate 100 also includes a stepped inner ring 102, an outer ring 103, and an L-shaped downward protruding structure 104. These structures, together with the customized rubber gasket 400 and the elastic element 200, form a complex labyrinthine sealing path. The elastic element 200 also includes an inner ring 206 and an outer ring 207, which are used for the positioning and installation of the structure, respectively.

[0060] The principle of this implementation is as follows: the O-ring 500 acts as the first barrier, blocking the penetration of liquid along the contact surfaces between the elastic element 200 and the upper and lower cover plates through precisely controlled compression; the customized rubber gasket 400 acts as the second barrier, filling the stepped gaps to prevent liquid from seeping in from the gap between the upper cover plate 100 and the load-bearing frustum 201 of the elastic element. If the O-ring develops micro-cracks due to aging, the adhesiveness of the rubber gasket can temporarily seal the cracks; if the rubber gasket is displaced by water flow, the rigid compression of the O-ring can still maintain the seal, forming redundant protection.

[0061] Specific Implementation Method Two: Combining Figures 1-5 This embodiment is based on the six-dimensional force sensor double-barrier sealing structure described in Specific Embodiment 1. The design method of the six-dimensional force sensor double-barrier sealing structure in this embodiment includes the following steps:

[0062] S1. Determine the stiffness of the elastic element and the sealing barrier scheme:

[0063] The equivalent stiffness K of the strain beam 208 of the elastic element 200 in the measurement direction is obtained. s ;

[0064] A dual-barrier sealing scheme was determined, using a custom-made 400 gasket for planar sealing and an O-ring 500 for radial sealing.

[0065] S2. Design and customize the hardness and structure of the rubber pad:

[0066] The equivalent stiffness K of the elastic element strain beam in the measurement direction s The customized rubber pad 400, compressed in the same direction by the pre-tightening force of the upper cover plate 100, has an equivalent stiffness of K. g To ensure that the custom-made rubber pad 400 does not negate the load that should be sensed by the strain beam, the following conditions must be met:

[0067] K g < <K s

[0068] Typically, when K is satisfied g ≤0.01K sAt this time, the impact of the custom rubber pad 400 on the overall stiffness and measurement accuracy of the sensor is negligible. Considering that the custom rubber pad 400 is mainly in a compressed state, its compressive stiffness K g It can be approximately estimated using the following formula:

[0069]

[0070] Among them, E g t is the compressive elastic modulus of the rubber pad material, A is the effective bearing area of ​​the rubber pad, and t is the thickness of the rubber pad.

[0071] Based on E g The Shore hardness of the custom rubber pad 400 is calculated and selected based on the empirical relationship model with Shore hardness HS to ensure that its stiffness does not affect the measurement accuracy of the sensor.

[0072] This empirical relationship model can be approximated as:

[0073]

[0074] By combining the above relationships, we can derive the formula for selecting the upper limit of the hardness of the custom rubber pad at 400:

[0075]

[0076] The structure of the custom rubber pad 400 is designed such that its upper surface forms a boss 402 that matches the stepped structure 101 of the upper cover plate 100, and its lower surface forms an L-shaped structure 403 that can extend into the annular protective groove 205 of the elastic element 200.

[0077] In a preferred embodiment of the present invention, the stiffness K of the elastic element 200 is... s The strength is approximately 1 × 10^6 N / mm², the effective bearing area A of the rubber pad is approximately 150 mm², and the thickness t is 2 mm. Substituting these values ​​into the above formula, we obtain:

[0078]

[0079] Solving this inequality yields HS ≤ 40. To provide sufficient design margin and ensure optimal flexible sealing, this embodiment preferably uses a custom-made gasket with a Shore hardness of 35 ± 5. This hardness range allows for effective filling of micro-gaps through elastic deformation to form a reliable seal, while also ensuring that its equivalent stiffness is much lower than that of the elastic element, thereby avoiding interference with the force transmission path of the sensor and guaranteeing the accuracy of six-dimensional force measurement.

[0080] S3. Design the sealing parameters for O-ring 500:

[0081] Based on the dimensions of the annular groove 204 on the elastic element 200, the cross-sectional diameter of the O-ring 500 is selected; the compression rate of the O-ring 500 is set to 15% to 25%, and the depth of the annular groove 204 is determined accordingly.

[0082] The theoretical basis lies in the fact that the sealing mechanism of an O-ring is based on the compression deformation of an elastic element. Let the diameter of the O-ring cross-section be d, and the groove depth be h (h = d - Δd, where Δd is the compression amount). After compression, the O-ring expands radially, generating a contact pressure P on the groove wall. Its theoretical value can be estimated by the following formula:

[0083]

[0084] Where k is the shape factor and E is the elastic modulus of the rubber. When P is greater than the external water pressure, an effective seal is formed. At the same time, the underwater pressure will further compress the O-ring, increasing its contact stress and creating a self-tightening characteristic of "the greater the pressure, the tighter the seal".

[0085] S4. Assembly and Verification:

[0086] The custom-made adhesive pad 400 is pre-fixed to the elastic element 200 using an adhesive.

[0087] The O-ring 500 is installed in the annular groove 204; the upper cover plate 100, the elastic element 200 equipped with the custom rubber gasket 400 and the O-ring 500, and the lower cover plate 300 are fastened together by locking components to form the double barrier sealing structure.

[0088] In this embodiment, the O-ring 500 and the customized rubber gasket 400 form a composite sealing system. Their synergistic effect is as follows: the O-ring 500 acts as the first barrier, blocking liquid penetration along the contact surfaces between the elastic element 200 and the upper cover plate 100 and lower cover plate 300 through precisely controlled compression; the customized rubber gasket 400 acts as the second barrier, filling the stepped gaps and preventing liquid from seeping in from the gap between the upper cover plate 100 and the load-bearing frustum 201 of the elastic element 200. If the O-ring 500 develops microcracks due to aging, the adhesiveness of the customized rubber gasket 400 can temporarily seal the cracks; if the customized rubber gasket 400 is displaced by water flow, the pressure deformation of the O-ring 500 can still maintain the seal, forming redundant protection.

[0089] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be permuted and combined. Those skilled in the art can exhaust all possibilities based on the mathematical knowledge of permutation and combination. Therefore, the present invention will not describe the technical solutions after permutation and combination one by one, but it should be understood that the technical solutions after permutation and combination have been disclosed by the present invention.

[0090] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A double-barrier sealing structure for a six-dimensional force sensor, characterized in that: Includes an upper cover plate (100), an elastic element (200), a lower cover plate (300), a custom rubber pad (400), and an O-ring (500). The elastic element (200) is clamped between the upper cover plate (100) and the lower cover plate (300). The upper cover plate (100) has a stepped structure (101) extending toward the elastic element (200), thereby forming an annular gap between the upper cover plate (100) and the load-bearing frustum (201) of the elastic element (200). A custom-made adhesive pad (400) is filled in the annular gap, and its lower surface covers the annular area surrounding the strain beam (208) on the upper surface of the elastic element (200), forming the first planar sealing barrier; The elastic element (200) has an annular groove (204) on both the upper surface (202) and the lower surface (203) of the elastic element (200), and an O-ring (500) is disposed in the annular groove (204); When the upper cover plate (100) and the lower cover plate (300) are fastened by the locking member, the O-ring (500) is squeezed and deformed, and fits tightly against the inner surface of the upper cover plate (100) or the lower cover plate (300) and the wall surface of the annular groove (204), forming a second radial sealing barrier.

2. The six-dimensional force sensor double-barrier sealing structure according to claim 1, characterized in that: The elastic element (200) has an annular protective groove (205) on its periphery of the load-bearing frustum (201). The lower surface of the custom-made rubber pad (400) has a downwardly protruding L-shaped structure (403) that extends into the annular protective groove (205), and there is a predetermined gap between its outer contour and the inner wall of the annular protective groove (205) for filling with sealant.

3. The six-dimensional force sensor double-barrier sealing structure according to claim 1, characterized in that: The upper surface of the custom rubber pad (400) has a stepped boss (402), which is adapted to the stepped structure (101) of the upper cover plate (100), and the fit gap between the two is no more than 0.1mm.

4. The six-dimensional force sensor double-barrier sealing structure according to claim 1, characterized in that: The custom rubber pad (400) is pre-fixed to the upper surface of the elastic element (200) by silicone rubber adhesive, and is fastened to the upper cover plate (100) by the outer ring screw and the inner ring screw of the rubber pad through itself; the outer ring screw and the inner ring screw of the rubber pad are provided with guide chamfers at the edge of the hole through the custom rubber pad (400).

5. The six-dimensional force sensor double-barrier sealing structure according to claim 1, characterized in that: The compression ratio of the O-ring (500) in the assembled state is designed to be 15% to 25%.

6. The six-dimensional force sensor double-barrier sealing structure according to claim 1, characterized in that: The inner wall of the annular groove (204) of the elastic element (200) is provided with micro-textures to increase adhesion.

7. The six-dimensional force sensor double-barrier sealing structure according to claim 1, characterized in that: The custom-made rubber pad (400) has a Shore hardness of 35±5.

8. A design method for a six-dimensional force sensor double-barrier sealing structure according to claim 1, characterized in that, Includes the following steps: S1. Determine the stiffness of the elastic element (200) and the sealing barrier scheme: The equivalent stiffness K of the strain beam (208) of the elastic element (200) in the measurement direction is obtained. s ; A dual-barrier sealing scheme was determined, using a custom rubber gasket (400) for planar sealing and an O-ring (500) for radial sealing; S2. Design the hardness and structure of the custom-made rubber pad (400): The equivalent stiffness K of the strain beam (208) of the elastic element (200) in the measurement direction s The customized rubber pad (400) is compressed in the same direction by the pre-tightening force of the upper cover plate (100), and its equivalent stiffness is K. g To ensure that the custom rubber pad (400) does not counteract the load that should be sensed by the strain beam (208), the following conditions must be met: K g <<K s When K is satisfied g ≤0.01K s At this time, the influence of the custom rubber pad (400) on the overall stiffness and measurement accuracy of the sensor is negligible. Considering that the custom rubber pad (400) is in a compressed state, its compressive stiffness K g Estimated using the following formula: Among them, E g t is the compressive elastic modulus of the rubber pad material, A is the effective bearing area of ​​the rubber pad, and t is the thickness of the rubber pad. Based on E g The Shore hardness of the custom rubber pad (400) is calculated and selected based on the empirical relationship model with Shore hardness HS to ensure that its stiffness does not affect the measurement accuracy of the sensor. The structure of the custom rubber pad (400) is designed such that its upper surface forms a boss (402) that matches the stepped structure (101) of the upper cover plate (100), and its lower surface forms an L-shaped structure (403) that can extend into the annular protective groove (205) of the elastic element (200). S3. Design the sealing parameters for the O-ring (500): The cross-sectional diameter of the O-ring (500) is selected according to the size of the annular groove (204) on the elastic element (200); The compression rate of the O-ring (500) is set to 15% to 25%, and the depth of the annular groove (204) is determined accordingly. S4. Assembly and Verification: The custom-made rubber pad (400) is pre-fixed to the elastic element (200) using an adhesive. The O-ring (500) is installed in the annular groove (204); The upper cover plate (100), the elastic element (200) equipped with the custom rubber gasket (400) and the O-ring (500) and the lower cover plate (300) are fastened together by locking components to form the double barrier sealing structure.

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