Hollow three-dimensional force sensor and working method thereof

Abstract

The invention discloses a hollow three-dimensional force sensor and a working method thereof. The hollow three-dimensional force sensor comprises an elastic body and a corrugated pipe, the elastic body is of a cylindrical structure with the square outside and the cylindrical inside, a hollow cavity is formed in the elastic body, the top-bottom direction is the Z direction, two opposite side faces are X-direction side faces, the other two opposite side faces are Y-direction side faces, the X-direction side faces and the Y-direction side faces are each provided with two rows of through holes formed at intervals, and beams are arranged between the vertically adjacent through holes. The height positions of the through holes in the X-direction side face and the Y-direction side face correspond, the through holes in the same height of the X-direction side face and the Y-direction side face are selected as induction areas, strain gauges are arranged in the through holes in the induction area of the X-direction side face, on the vertical side wall and on the beam, and strain gauges are arranged in the through holes in the induction area of the Y-direction side face and on the beam; round through holes are formed in the top end and the bottom end of the elastic body and connected with the two ends of the corrugated pipe respectively. The sensor allows high-pressure fluid to pass through the interior of the sensor, the three-dimensional force borne by the sensor is accurately, safely, stably and reliably measured, and the sensor is suitable for being applied to complex environments.

Description

Technical Field

[0001] The invention belongs to the field of three-dimensional force sensors and relates to a hollow three-dimensional force sensor and a working method thereof. Background Art

[0002] The technology of three-dimensional force sensors based on the principle of resistance strain is relatively mature in China, and is mostly implemented in frame-type and multi-column structures. On the one hand, the size or output sensitivity of the three-dimensional force measured by the multi-column structure is subject to certain limitations. For example, the Z-axis axial force has a larger range of more than tons, and is about twice the lateral force in the X or Y direction, but the output sensitivity is relatively small; on the other hand, the three-dimensional force measured by the frame structure has a smaller range of kilograms, and the size or output sensitivity is similar, but the structure size is larger. These structures cannot achieve the passage of high-pressure fluid through the inside of the three-dimensional force sensor and accurately, safely, stably and reliably measure the three-dimensional force it is subjected to. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a hollow three-dimensional force sensor and a working method thereof, which allows high-pressure fluid to pass through the interior thereof and can accurately, safely, stably and reliably measure the three-dimensional force it is subjected to, and is adaptable to applications in complex environments.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions: A hollow three-dimensional force sensor comprises an elastic body and a bellows; The elastic body is a cylindrical structure with a square outside and a cylindrical inside, and the inside is a hollow cavity, the top and bottom direction is the Z direction, two opposite side surfaces are X-direction side surfaces, and the other two opposite side surfaces are Y-direction side surfaces, and the X-direction side surfaces and the Y-direction side surfaces are both provided with two rows of through holes arranged at intervals, and a beam is provided between the upper and lower adjacent through holes, and the height positions of the through holes of the X-direction side surfaces and the Y-direction side surfaces correspond, and the through holes of the same height are selected as the sensing area of ​​the X-direction side surfaces and the Y-direction side surfaces, and strain gauges are provided on the vertical side walls and the beams in the through holes of the sensing area of ​​the X-direction side surfaces, and strain gauges are provided on the beams in the through holes of the sensing area of ​​the Y-direction side surfaces; Circular through holes are arranged at both ends of the top and bottom of the elastic body, and the circular through holes are communicated with the internal cavity. Both ends of the bellows are connected to the circular through holes at both ends of the top and bottom of the elastic body respectively.

[0005] Preferably, the width of the through hole of the sensing area on the X-direction side is smaller than that of the through hole of the sensing area on the Y-direction side, and the thickness of the beam with the strain gauge on the X-direction side is smaller than that of the beam with the strain gauge on the Y-direction side.

[0006] Preferably, a limiting gap is provided near the lower end of the elastic body, and the limiting gap connects the two through holes at the bottom.

[0007] Furthermore, the middle of the limiting gap is an I-shaped structure.

[0008] Preferably, a groove is provided between two rows of through holes in the X-direction side surface and the Y-direction side surface.

[0009] Preferably, the number of the inner concave corrugations and the outer convex corrugations of the bellows is the same.

[0010] Preferably, the diameter of the through hole at the top of the elastomer is equal to the minimum diameter of the inner wall of the concave corrugation in the middle of the bellows, the diameter of the through hole at the bottom of the elastomer is equal to the maximum diameter of the inner wall of the convex corrugation in the middle of the bellows, and a connecting ring is provided on the top of the elastomer, the connecting ring is connected to the through hole at the top of the elastomer, the inner wall of the connecting ring and the inner wall of the through hole at the top of the elastomer are in a circular arc transition, the outer diameter of the connecting ring is equal to the maximum diameter of the inner wall of the convex corrugation in the middle of the bellows, and the inner diameter of the connecting ring is larger than the minimum diameter of the inner wall of the concave corrugation in the middle of the bellows.

[0011] Furthermore, two ends of the bellows are respectively connected to the circular through holes at two ends of the elastic body.

[0012] Preferably, a gap is provided between the middle outer wall portion of the bellows and the inner wall of the elastomer.

[0013] A working method of a hollow three-dimensional force sensor. When a high-pressure fluid passes through, the pressure of the high-pressure fluid acts on the inner wall of the bellows radially, and balance is achieved through the circumferential tension of the inner wall of the bellows. The pressure of the high-pressure fluid acts on the inner wall of the bellows along the Z-axis, causing axial compression deformation of the concave corrugations inside the bellows and axial tensile deformation of the convex corrugations outside the bellows. The axial deformations of the bellows offset each other without affecting the effective deformation of the elastic body. The strain gauges in the sensing area respectively obtain the deformation amounts in three directions, thereby realizing high-precision measurement of the forces in three directions on the top of the elastic body.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention uses a hollow three-dimensional force sensor to convert the X-direction or Y-direction lateral force into a Y-direction or X-direction bending moment component, and then convert it into the corresponding axial force component of the X-direction or Y-direction lateral force, with high decoupling accuracy, and realizes three-dimensional force measurement suitable for large and small ranges. The structure has a small size, allows high-pressure fluid to pass through it, and accurately, safely, stably and reliably measures the three-dimensional force it is subjected to, and is suitable for complex environments such as dust, smoke, electromagnetic fields, etc., filling the domestic gap.

[0015] Furthermore, since the strain gauge for measuring the Z-direction deformation is located on the X-direction side, when the Z-direction is subjected to the same force, the Z-direction force component distributed in the resistance strain sensing area subjected to the Z-direction force is increased through deformation coordination, thereby improving the output sensitivity, structure and decoupling accuracy of the Wheatstone bridge for Z-direction measurement and improving the processing processability.

[0016] Furthermore, the limit gaps respectively realize overload protection for forces in the X-direction, Y-direction, and Z-direction, ensuring the safety and reliability of the measurement and structure of the hollow three-dimensional force sensor under complex force fields.

[0017] Furthermore, a groove is provided between each of the two rows of through holes, which increases the deformation of the elastic body of the hollow three-dimensional force sensor while also reducing weight.

[0018] Furthermore, the number of concave corrugations inside the bellows and convex corrugations outside is the same, so that the deformation caused by compression and stretching in each axial part is equal. Furthermore, the area of ​​the last wave pressure surface at the top of the circular thin-walled bellows is the same as the area of ​​the side wall and end face of the connecting ring. The two forces of high-pressure fluid acting on the corrugated inner wall at the top of the circular thin-walled bellows along the Z-axis and acting on the inner wall and end face of the connecting ring through the rigid top of the circular thin-walled bellows are equal in magnitude and opposite in direction, thereby achieving balance, so that the multi-parallel beam through-type hollow structure in the middle of the elastic body of the three-dimensional force sensor that is sensitive to three-dimensional force is not affected by pressure changes, thereby realizing accurate, safe, stable and reliable measurement of three-dimensional force without being affected by changes in high-pressure fluid pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the external structure of the hollow three-dimensional force sensor of the present invention; Figure 2 It is a cross-sectional schematic diagram of the hollow three-dimensional force sensor of the present invention.

[0020] Among them: 1-elastic body; 2-bellows; 3-limiting gap; 4-weld. DETAILED DESCRIPTION

[0021] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0022] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs. The terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. The term "and / or" used in this article includes any and all combinations of one or more related listed items. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0024] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplicity and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides various specific examples of processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0025] like Figure 1As shown, the hollow three-dimensional force sensor of the present invention provides a hollow three-dimensional force sensor that allows high-pressure fluid to pass through its interior and is adaptable to accurately, safely, stably and reliably measure the three-dimensional force it is subjected to in complex environments.

[0026] The hollow three-dimensional force sensor comprises an elastic body 1, a bellows 2, a housing component, a resistance strain gauge and a Wheatstone bridge composed of the elastic body 1, a bellows 2, a housing component, and a resistance strain gauge.

[0027] In this article, the elastic body 1 is a hollow three-dimensional force sensor elastic body, and the bellows 2 is a round thin-walled bellows.

[0028] The hollow three-dimensional force sensor elastic body is a cylindrical structure with an outer square and an inner cylindrical structure, and the interior is a hollow cavity to enhance strength and adaptability. The top and bottom directions are in the Z direction, two opposite sides are X-direction sides, and the other two opposite sides are Y-direction sides. The four cylinder walls of the X-direction side and the Y-direction side are multi-parallel beam through-type hollow structures to ensure sensitivity to force. The specific multi-parallel beam through-type hollow structure includes two rows of through holes arranged at intervals, and beams are between the upper and lower adjacent through holes. The through holes on the X-direction side are in the X direction, the through holes on the Y-direction side are in the Y direction, and the through holes on the X-direction side are in the X direction. Corresponding to the height position of the through hole on the Y-direction side, through holes of the same height are selected on the X-direction side and the Y-direction side to set strain gauges as the sensing area of ​​the hollow three-dimensional force sensor elastic body. In the through hole of the sensing area on the X-direction side, strain gauges are set on the vertical side walls and the beam for detecting X-direction and Z-direction deformations. The width of the through hole in the sensing area on the X-direction side is Lx, and the thickness of the beam with the strain gauge is Hx; in the through hole of the sensing area on the Y-direction side, strain gauges are set on the beam for detecting Y-direction deformation. The width of the through hole in the sensing area on the Y-direction side is Ly, and the thickness of the beam with the strain gauge is Hy.

[0029] A limit gap 3 is designed near the lower end of the elastic body of the hollow three-dimensional force sensor. The limit gap 3 is set at the connecting line of the top edges of the two bottom through holes. The limit gap 3 connects the top edges of the two bottom through holes. The middle of the limit gap 3 is an I-shaped structure, which respectively realizes overload protection for forces in the X direction, Y direction, and Z direction, thereby ensuring the safety and reliability of the measurement and structure of the hollow three-dimensional force sensor under complex force fields.

[0030] The above-mentioned resistance strain gauge and the Wheatstone bridge composed of them are respectively arranged in the resistance strain sensing area of ​​the X-direction, Y-direction, and Z-direction force of the parallel beam structure of the cylinder wall on both sides of the X-direction and Y-direction of the hollow three-dimensional force sensor elastic body; the three-dimensional force sensor elastic body 1 bears the force in the X-direction, Y-direction, and Z-direction, and converts the X-direction or Y-direction lateral force into the Y-direction or X-direction bending moment component, and then converts it into the axial force component corresponding to the X-direction or Y-direction lateral force. The X-direction, Y-direction, and Z-direction measurement Wheatstone bridge composed of specific resistance strain gauges realizes high-precision decoupling of the structure and bridge of the measured three-dimensional force. In addition, the measurement sensitivity of different force sizes in the X-direction, Y-direction, and Z-direction can be achieved by adjusting the structural dimensions such as dimensions Hx, Hy, Lx, and Ly.

[0031] As mentioned above, when the forces in the X and Y directions are the same, within a certain range, by increasing Hy and Ly and matching with the reduction of Lx and Hx, in this process, the ratio of Hy and Ly remains unchanged as do Lx and Hx, so that the output sensitivity of the Wheatstone bridge when the forces in the X and Y directions are the same can be made equal; and increasing Hy and Ly and matching with the reduction of Lx and Hx changes the stiffness of the parallel beam structure in the resistance strain sensing area under the forces in the corresponding X and Y directions, so that when the forces in the Z direction are the same, before and after increasing Hy and Ly and matching with the reduction of Lx and Hx, the Z-direction component force distributed in the resistance strain sensing area under the forces in the Z direction increases through deformation coordination, thereby improving the output sensitivity, structure and decoupling accuracy of the Wheatstone bridge for Z-direction measurement, and improving the processing technology.

[0032] A groove is provided between the two rows of through holes on the X-direction side and the Y-direction side. The sizes of the grooves on the X-direction side and the Y-direction side can be the same or different, and the structures are both rectangular. While increasing the deformation of the elastic body of the hollow three-dimensional force sensor, weight reduction is also achieved.

[0033] The above-mentioned circular thin-walled bellows is assembled inside the hollow three-dimensional force sensor elastic body, with welds 4 welded at both ends. The shell component is located outside the hollow three-dimensional force sensor elastic body, and the shell component is used to protect the line leading out of the strain gauge.

[0034] like Figure 2As shown, circular through holes are provided at both ends of the top and bottom of the hollow three-dimensional force sensor elastomer, and the circular through holes are connected to the internal cavity. The diameter of the top through hole of the hollow three-dimensional force sensor elastomer is equal to the minimum diameter of the inner wall of the concave corrugation in the middle of the circular thin-walled bellows, and the diameter of the bottom through hole of the hollow three-dimensional force sensor elastomer is equal to the maximum diameter of the inner wall of the convex corrugation in the middle of the circular thin-walled bellows. A connecting ring is provided on the top of the hollow three-dimensional force sensor elastomer, and the connecting ring is connected to the top through hole of the hollow three-dimensional force sensor elastomer. The inner wall of the connecting ring and the inner wall of the top through hole of the hollow three-dimensional force sensor elastomer are in a circular arc transition. The outer diameter of the connecting ring is equal to the maximum diameter of the inner wall of the convex corrugation in the middle of the circular thin-walled bellows, and the inner diameter of the connecting ring is larger than the minimum diameter of the inner wall of the concave corrugation in the middle of the circular thin-walled bellows.

[0035] The two ends of the circular thin-walled bellows are respectively connected to the top and bottom ends of the hollow three-dimensional force sensor elastic body, the diameter of the top through hole of the hollow three-dimensional force sensor elastic body is smaller than the diameter of the bottom through hole, the top diameter of the circular thin-walled bellows is smaller than the bottom diameter, the top diameter of the circular thin-walled bellows is equal to the minimum diameter of the inner wall of the concave corrugation in the middle of the circular thin-walled bellows, and the bottom diameter of the circular thin-walled bellows is equal to the maximum diameter of the inner wall of the convex corrugation in the middle of the circular thin-walled bellows.

[0036] The above hollow three-dimensional force sensor, when the two ends of the hollow three-dimensional force sensor elastic body are used in conjunction with an axial or end face sealing structure, the two ends of the circular thin-walled bellows are respectively welded to the circular through holes at the two ends of the hollow three-dimensional force sensor elastic body, so that high-pressure fluids such as gas or liquid can be allowed to pass through the hollow interior of the hollow three-dimensional force sensor without leakage. Since the circular thin-walled bellows are respectively welded to the two ends of the hollow three-dimensional force sensor elastic body, the outer wall of the middle circular thin-walled bellows retains a small gap with the inner wall of the hollow three-dimensional force sensor elastic body, and the cylindrical parts at both ends are in a small interference fit relationship with the inner wall of the hollow three-dimensional force sensor elastic body, and the inner diameter of the cylindrical surface at the bottom end of the circular thin-walled bellows and the maximum diameter of the inner wall of the convex corrugated outer wall in the middle of the circular thin-walled bellows are the same as the outer diameter of the connecting ring.

[0037] When high-pressure fluid passes through, on the one hand, the high-pressure fluid pressure acts on the inner wall of the circular thin-walled bellows radially, and is balanced by the circumferential tension of the inner wall of the circular thin-walled bellows, so that the radial pressure component does not affect the precise measurement of the three-dimensional force; on the other hand, the high-pressure fluid pressure acts on the inner wall of the circular thin-walled bellows along the Z-axis, squeezing the inner concave corrugations of the circular thin-walled bellows to produce axial squeezing deformation, and stretching the outer convex corrugations of the circular thin-walled bellows to produce axial tensile deformation. The axial deformations of the circular thin-walled bellows offset each other without affecting the effective deformation of the elastomer. The strain gauges in the sensing area respectively obtain the deformation in three directions, thereby realizing high-precision measurement of the forces in three directions on the top of the elastomer.

[0038] Through design, the number of concave corrugations and convex corrugations in the circular thin-walled bellows is the same, and the deformation caused by extrusion and stretching is equal. At the same time, since the inner diameter of the cylindrical surface at the bottom of the circular thin-walled bellows, the maximum diameter of the inner wall of the convex corrugations in the middle of the circular thin-walled bellows, and the outer diameter of the connecting ring are all the same, the area of ​​the last wave pressure surface at the top of the circular thin-walled bellows is the same as the side wall and end surface area of ​​the connecting ring. The high-pressure fluid acts on the inner wall of the corrugated top of the circular thin-walled bellows along the Z axis as the first acting pressure, and the high-pressure fluid acts on the inner wall and end surface of the connecting ring along the Z axis through the rigid top of the circular thin-walled bellows as the second acting pressure. The first acting pressure and the second acting pressure are equal in magnitude and opposite in direction, thereby achieving balance, so that the multi-parallel beam through-type hollow structure in the middle of the hollow three-dimensional force sensor elastic body that is sensitive to three-dimensional force is not affected by pressure changes, thereby realizing accurate, safe, stable and reliable measurement of three-dimensional force without being affected by high-pressure fluid pressure changes.

[0039] The above-mentioned hollow three-dimensional force sensor allows high-pressure fluid to pass through its interior, and is suitable for accurately, safely, stably and reliably measuring the three-dimensional force it is subjected to in complex environments. It is also suitable for complex environments such as dust, smoke, electromagnetic fields, etc., filling a domestic gap.

[0040] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0041] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0042] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0043] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0044] The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

[0045] It should be understood that the above description is for illustration and not for limitation. Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this patent should not be determined with reference to the above description, but rather with reference to the preceding claims and the full scope of equivalents to which such claims are entitled. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended to be a waiver of such subject matter, nor should it be considered that the applicant has not considered such subject matter to be part of the disclosed inventive subject matter.

Claims

1. A hollow three-dimensional force sensor, characterized in that: It comprises an elastic body (1) and a bellows (2); The elastic body (1) is a cylindrical structure with a square outside and a cylindrical inside, and the inside is a hollow cavity, the top and bottom directions are the Z direction, two opposite side surfaces are X-direction side surfaces, and the other two opposite side surfaces are Y-direction side surfaces, the X-direction side surfaces and the Y-direction side surfaces are both provided with two rows of through holes arranged at intervals, a beam is provided between the upper and lower adjacent through holes, the through holes on the X-direction side surfaces and the Y-direction side surfaces have corresponding height positions, through holes at the same height on the X-direction side surfaces and the Y-direction side surfaces are selected as sensing areas, strain gauges are provided on the vertical side walls and on the beams in the sensing area through holes on the X-direction side surfaces, and strain gauges are provided on the beams in the sensing area through holes on the Y-direction side surfaces; Circular through holes are provided at both ends of the top and bottom of the elastic body (1), the circular through holes are connected to the internal cavity, and the two ends of the bellows (2) are respectively connected to the circular through holes at the top and bottom ends of the elastic body (1).

2. The hollow three-dimensional force sensor according to claim 1, characterized in that: The through hole width of the sensing area on the X-direction side is smaller than that on the Y-direction side, and the thickness of the beam with the strain gauge on the X-direction side is smaller than that on the Y-direction side.

3. The hollow three-dimensional force sensor according to claim 1, characterized in that: A limiting gap (3) is provided near the lower end of the elastic body (1), and the limiting gap (3) connects the two through holes at the bottom.

4. The hollow three-dimensional force sensor according to claim 3, characterized in that: The middle of the limiting gap (3) is an I-shaped structure.

5. The hollow three-dimensional force sensor according to claim 1, characterized in that: A groove is arranged between two rows of through holes on the X-direction side surface and the Y-direction side surface.

6. The hollow three-dimensional force sensor according to claim 1, characterized in that: The number of the inner concave corrugations and the outer convex corrugations of the bellows (2) is the same.

7. The hollow three-dimensional force sensor according to claim 1, characterized in that: The diameter of the through hole at the top of the elastic body (1) is equal to the minimum diameter of the inner wall of the concave corrugation in the middle of the bellows (2), and the diameter of the through hole at the bottom of the elastic body (1) is equal to the maximum diameter of the inner wall of the convex corrugation in the middle of the bellows (2). A connecting ring is arranged at the top of the elastic body (1), the connecting ring is connected to the through hole at the top of the elastic body (1), the inner wall of the connecting ring is in a circular arc transition with the inner wall of the through hole at the top of the elastic body (1), the outer diameter of the connecting ring is equal to the maximum diameter of the inner wall of the convex corrugation in the middle of the bellows (2), and the inner diameter of the connecting ring is greater than the minimum diameter of the inner wall of the concave corrugation in the middle of the bellows (2).

8. The hollow three-dimensional force sensor according to claim 7, characterized in that: The two ends of the bellows (2) are respectively connected to the circular through holes at the two ends of the elastic body (1).

9. The hollow three-dimensional force sensor according to claim 1, characterized in that: A gap is provided between the middle outer wall portion of the bellows (2) and the inner wall of the elastic body (1).

10. A working method of the hollow three-dimensional force sensor according to any one of claims 1 to 9, characterized in that: When high-pressure fluid passes through, the pressure of the high-pressure fluid acts on the inner wall of the bellows (2) in the radial direction, and balance is achieved through the circumferential tension of the inner wall of the bellows (2). The pressure of the high-pressure fluid acts on the inner wall of the bellows (2) in the Z-axis direction, squeezing the concave corrugations of the bellows (2) to produce axial squeezing deformation, and stretching the convex corrugations of the bellows (2) to produce axial tensile deformation. The axial deformations of the bellows (2) offset each other without affecting the effective deformation of the elastic body (1). The strain gauges in the sensing area respectively obtain the deformation amounts in three directions, thereby realizing the measurement of the forces in three directions on the top of the elastic body (1).

Images