Force, temperature and displacement sensor and manufacturing method thereof

Abstract

The invention provides a force, temperature and displacement sensor and a manufacturing method thereof, and relates to the technical field of sensors, and the sensor comprises a housing which is an elastic drum-shaped cylinder; one end of the inner cylinder is connected with one end of the shell in a sealed mode, one end of the outer cylinder is connected with the other end of the shell in a sealed mode, the other end of the inner cylinder is movably arranged in the other end of the outer cylinder in a penetrating mode, a gap is formed between the other end of the inner cylinder and the other end of the outer cylinder, and capacitor plates are arranged on the outer side of the other end of the inner cylinder and the inner side of the other end of the outer cylinder. Temperature measuring devices are arranged on the inner side of the other end of the inner cylinder and the outer side of the other end of the outer cylinder; the two elastomers are hermetically connected into one end of the inner cylinder and one end of the outer cylinder respectively, a strain resistor is arranged on the side, close to the interior of the shell, of the bottom plate, and an external connection part is arranged on the side, close to the exterior of the shell, of the bottom plate; the problems that in the prior art, a sensor for measuring force, temperature and displacement is complex in structure, large in size and weight, low in integration level and not suitable for the small-sized electric servo working condition are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of sensors, and more specifically, relates to a force, temperature and displacement sensor and a manufacturing method thereof. Background Art

[0002] Force, temperature and displacement are three physical quantities that must be obtained for closed-loop control and safety in some electric servo control fields. Traditional sensors of this type usually require connecting force and spring in series, installing displacement sensors to measure spring displacement, and additionally setting temperature sensors to complete the measurement of multiple physical quantities. Such force, temperature and displacement sensors have complex structures, large volumes and weights, and are not suitable for miniaturized electric servo applications. Therefore, the industry needs a highly integrated, miniaturized multi-physical quantity measurement sensor. Summary of the invention

[0003] The purpose of the present invention is to provide a force, temperature and displacement sensor and a manufacturing method thereof in view of the deficiencies in the prior art, so as to solve the problems that the sensors for measuring force, temperature and displacement in the prior art have complex structures, large volumes and weights, low integration, and are not suitable for miniaturized electric servo working conditions.

[0004] In order to achieve the above object, the present invention provides a force, temperature and displacement sensor, comprising:

[0005] An outer shell, wherein the outer shell is an elastic drum-shaped tube;

[0006] An inner tube and an outer tube, one end of the inner tube is sealedly connected to one end of the outer tube, one end of the outer tube is sealedly connected to the other end of the outer tube, the other end of the inner tube is movably inserted into the inside of the other end of the outer tube to form a gap, a capacitor plate is arranged on the outside of the other end of the inner tube and the inside of the other end of the outer tube, and a temperature measuring device is arranged on the inside of the other end of the inner tube and the outside of the other end of the outer tube;

[0007] Two elastic bodies, the two elastic bodies are respectively sealed and connected to the inside of one end of the inner cylinder and the inside of one end of the outer cylinder, the elastic body is a cylinder with a bottom plate, a strain resistor is arranged on one side of the bottom plate close to the inside of the shell, and an external connection part is arranged on one side of the bottom plate close to the outside of the shell;

[0008] A processor is electrically connected to the capacitor plate, the temperature measuring device and the strain resistor.

[0009] Optionally, the processor includes a temperature measurement module, a Wheatstone bridge circuit and a capacitor bridge circuit, the temperature measurement module is electrically connected to the temperature measurement device, the Wheatstone bridge circuit is electrically connected to the strain resistor, and the capacitor bridge circuit is electrically connected to the capacitor plate.

[0010] Optionally, a closed space is formed in the shell, and the closed space is in a vacuum state or is filled with an inert gas or has a moisture absorbing component placed therein.

[0011] Optionally, an annular groove is provided on the inner circumferential surface of the shell.

[0012] Optionally, the capacitor plates, the temperature measuring device and the strain resistor are all connected with wires, the shell and the outer cylinder are coaxially provided with through holes, the through holes can accommodate the wires to pass through so that the wires can be led out, and a sealing portion is provided in the through holes.

[0013] Optionally, the through holes are evenly distributed along the circumference of the shell.

[0014] Optionally, the inner cylinder includes a first cylindrical portion and a second cylindrical portion, the first cylindrical portion and the second cylindrical portion are integrally connected via a first step portion, the diameter of the first cylindrical portion is greater than the diameter of the second cylindrical portion, the first cylindrical portion and the second cylindrical portion respectively form one end of the inner cylinder and the other end of the inner cylinder, and the outer cylinder includes a third cylindrical portion and a fourth cylindrical portion, the third cylindrical portion and the fourth cylindrical portion are integrally connected via a second step portion, the diameter of the third cylindrical portion is greater than the diameter of the fourth cylindrical portion, the third cylindrical portion and the fourth cylindrical portion respectively form one end of the outer cylinder and the other end of the outer cylinder, and the second cylindrical portion is partially penetrated into the interior of the fourth cylindrical portion to form the gap.

[0015] Optionally, the external connection portion includes a conical structure arranged at the center position of one side of the base plate close to the outside of the shell, and a mounting hole is arranged at the center position of the conical structure. A part of the strain resistors is located close to the inner wall of the cylinder, and another part of the strain resistors is located close to the wall of the mounting hole.

[0016] The present invention also provides a method for manufacturing a force, temperature and displacement sensor, which is used to manufacture the force, temperature and displacement sensor, comprising:

[0017] A strain resistor is arranged on the elastic body;

[0018] A capacitor plate is arranged on the outer side of the other end of the inner tube and the inner side of the other end of the outer tube, and a temperature measuring device is arranged on the inner side of the other end of the inner tube and the outer side of the other end of the outer tube;

[0019] One end of the inner tube is sealedly connected to one end of the outer shell, and one end of the outer tube is sealedly connected to the other end of the outer shell, so that the other end of the inner tube is movably inserted into the other end of the outer tube, and the capacitor plates on the outer side of the inner tube and the inner side of the outer tube correspond to each other;

[0020] The capacitor plates, the temperature measuring device and the strain resistor are electrically connected to a processor so that the processor processes the signals of the capacitor plates, the temperature measuring device and the strain resistor and outputs displacement, temperature and force signals.

[0021] Optionally, the processor includes a temperature measurement module, a Wheatstone bridge circuit and a capacitor bridge circuit, the temperature measurement module is electrically connected to the temperature measurement device, the Wheatstone bridge circuit is electrically connected to the strain resistor, and the capacitor bridge circuit is electrically connected to the capacitor plate;

[0022] The temperature measuring module processes the signal of the temperature measuring device and outputs the temperature signal;

[0023] The signal of the strain resistor is processed by a Wheatstone bridge circuit and a force signal is output;

[0024] The capacitor plate signal is processed by a capacitor bridge circuit and a displacement signal is output.

[0025] The present invention provides a force, temperature and displacement sensor and a manufacturing method thereof, which has the beneficial effects that: the force, temperature and displacement sensor can simultaneously obtain a load force value, a temperature value and a displacement amount; when an external force acts on an elastic body in the form of tension or compression, a surface of the elastic body provided with a strain resistor will produce a tensile strain or a compressive strain; a processor can form a Wheatstone bridge with strain resistors that sense the tensile strain and the compressive strain, thereby realizing the measurement of the force value; at the same time, the curvature of the drum-shaped surface of the shell will change under the action of tension or pressure; by reducing the shell wall thickness, adjusting the shell curvature and the like, the amount of change in the curvature of the drum-shaped surface under the same force can be adjusted; the change in curvature can realize the inner and outer cylinders. The change in the length of the axial plug-in area of ​​the cylinder will be converted into a change in the capacitance of the capacitor composed of the corresponding capacitor plates of the inner cylinder and the outer cylinder. The processor can output an electrical signal through a capacitor bridge circuit to characterize the displacement of the inner cylinder and the outer cylinder along the axis. This change is close to a linear change. At the same time, the temperature measuring device is electrically connected to the processor to achieve the measurement of the temperature value. The force, temperature and displacement sensor has a simple structure, small size and weight, and high integration. It is not only suitable for miniaturized electric servo working conditions, but also simple to manufacture, low cost, and can adapt to various harsh working conditions, with high reliability and excellent performance. It has a significant effect on improving equipment reliability and environmental adaptability.

[0026] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0028] Figure 1 A schematic cross-sectional structure diagram of a force, temperature and displacement sensor according to an embodiment of the present invention is shown.

[0029] Figure 2 A schematic diagram of a three-dimensional cross-sectional structure of a force, temperature and displacement sensor according to an embodiment of the present invention is shown.

[0030] Figure 3 A schematic structural diagram of a force, temperature and displacement sensor under tension according to an embodiment of the present invention is shown.

[0031] Figure 4 A schematic structural diagram of a force, temperature and displacement sensor under pressure according to an embodiment of the present invention is shown.

[0032] Figure 5 A flow chart of a method for manufacturing a force, temperature and displacement sensor according to an embodiment of the present invention is shown.

[0033] Description of reference numerals:

[0034] 1. Shell; 2. Inner tube; 3. Outer tube; 4. Elastomer; 5. Temperature measuring device; 6. Capacitor plates; 101. Through hole of shell; 102. Annular groove; 103. Wire; 301. Through hole of outer tube; 401. Strain resistor. DETAILED DESCRIPTION

[0035] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0036] like Figures 1 to 4 As shown, the present invention provides a force, temperature and displacement sensor, comprising:

[0037] The outer shell 1 is a drum-shaped tube with elasticity;

[0038] An inner tube 2 and an outer tube 3, one end of the inner tube 2 is sealed and connected to one end of the outer shell 1, one end of the outer tube 3 is sealed and connected to the other end of the outer shell 1, the other end of the inner tube 2 is movably arranged inside the other end of the outer tube 3 to form a gap, a capacitor plate 6 is arranged on the outer side of the other end of the inner tube 2 and the inner side of the other end of the outer tube 3, and a temperature measuring device 5 is arranged on the inner side of the other end of the inner tube 2 and the outer side of the other end of the outer tube 3;

[0039] Two elastic bodies 4, the two elastic bodies 4 are respectively sealed and connected to the inside of one end of the inner tube 2 and the inside of one end of the outer tube 3, the elastic body 4 is a cylinder with a bottom plate, a strain resistor 401 is provided on one side of the bottom plate close to the inside of the outer shell 1, and an external connection part is provided on one side of the bottom plate close to the outside of the outer shell 1;

[0040] A processor is electrically connected to the capacitor plate 6 , the temperature measuring device 5 and the strain resistor 401 .

[0041] Specifically, in order to solve the problems in the prior art that sensors for measuring force, temperature and displacement are complex in structure, large in size and weight, low in integration, and not suitable for miniaturized electric servo working conditions; the force, temperature and displacement sensors provided by the present invention can simultaneously obtain the load force value, temperature value, and displacement value. When the external force acts on the elastic body 4 in the form of tension or compression, the surface of the elastic body 4 provided with the strain resistor 401 will produce tensile strain or compressive strain. The processor can form a Wheatstone bridge with the strain resistor 401 that senses the tensile strain and the compressive strain, so as to realize the measurement of the force value. At the same time, the curvature of the drum-shaped surface of the shell 1 will change under the action of tension or pressure. The curvature of the drum-shaped surface can be adjusted under the same force by reducing the wall thickness of the shell 1, adjusting the curvature of the shell 1, etc. The change in curvature can realize the change in the length of the axial plug-in area of ​​the inner tube 2 and the outer tube 3. This change will be converted into a change in the capacitance value of the capacitor composed of the capacitor plates 6 corresponding to the inner tube 2 and the outer tube 3. The processor can output an electrical signal through a capacitor bridge circuit to characterize the displacement of the inner tube 2 and the outer tube 3 along the axis. This change is close to a linear change. At the same time, the temperature measuring device 5 is electrically connected to the processor to realize the measurement of the temperature value; the force, temperature and displacement sensor has a simple structure, a small volume and weight, and a high degree of integration. It is not only suitable for miniaturized electric servo working conditions, but also simple to manufacture, low cost, and can adapt to various harsh working conditions, with high reliability and excellent performance, which has a significant effect on improving equipment reliability and environmental adaptability.

[0042] In this embodiment, an insulating layer is provided between the capacitor plate 6 and the inner tube 2 and between the capacitor plate 6 and the outer tube 3 .

[0043] Optionally, the processor includes a temperature measurement module, a Wheatstone bridge circuit and a capacitor bridge circuit, the temperature measurement module is electrically connected to the temperature measurement device 5, the Wheatstone bridge circuit is electrically connected to the strain resistor 401, and the capacitor bridge circuit is electrically connected to the capacitor plate 6.

[0044] Specifically, the temperature measuring module processes the signal of the temperature measuring device 5 and outputs a temperature signal; the Wheatstone bridge circuit processes the signal of the strain resistor 401 and outputs a force signal; the capacitor bridge circuit processes the signal of the capacitor plate 6 and outputs a displacement signal.

[0045] Optionally, a closed space is formed in the housing 1, and the closed space is in a vacuum state or is filled with an inert gas or has a moisture absorbing component placed therein.

[0046] Specifically, in order to reduce the influence of non-displacement changes on the capacitance change, a humidity-stable sealed environment is formed inside the housing 1, such as forming a vacuum state or an inert gas-filled state or placing a desiccant to absorb moisture, thereby improving the measurement accuracy of the displacement.

[0047] Furthermore, the temperature value measured by the temperature measuring device 5 can be used not only to provide the temperature value, but also to compensate or correct the temperature error caused by the displacement and force value being affected by temperature.

[0048] Optionally, an annular groove 102 is provided on the inner circumferential surface of the housing 1 .

[0049] Specifically, by setting the annular groove 102, the curvature change of the drum-shaped surface can be adjusted under the same force; the force, temperature and displacement sensor is provided with capacitor plates 6 on the inner cylinder 2 and the outer cylinder 3. When the inner cylinder 2 and the outer cylinder 3 produce relative displacement, the change of this displacement is converted into the change of the capacitance value of the capacitor. With the help of a processor, an electrical signal output can be realized through a capacitor bridge circuit to represent the displacement of the inner cylinder 2 and the outer cylinder 3 along the axial direction.

[0050] Optionally, 1 to 3 capacitor plates 6 are respectively disposed on the outer side of the inner cylinder 2 and the inner side of the outer cylinder 3 .

[0051] In this embodiment, four strain resistors 401 are arranged on the bottom plate of each elastic body 4 .

[0052] Optionally, the capacitor plate 6, the temperature measuring device 5 and the strain resistor 401 are all connected to a wire 103, and the shell 1 and the outer cylinder 3 are coaxially provided with a through hole, which can accommodate the wire 103 to pass through so that the wire 103 can be led out, and a sealing portion is provided in the through hole.

[0053] Specifically, the capacitor plate 6, the temperature measuring device 5 and the strain resistor 401 can all be electrically connected to the processor through the wire 103, and the processor can be set outside the shell 1; the setting of the through hole can allow the wire 103 to pass through, so as to realize the lead-out of the wire 103, and the sealing part can seal the through hole of the lead-out wire 103 to ensure that a closed space is formed inside the shell 1, and the sealing part can use sealant.

[0054] Optionally, the through holes are evenly distributed along the circumference of the housing 1 .

[0055] Specifically, the through holes need to be evenly arranged along the circumference of the housing 1 to ensure the symmetry of the deformation of the housing 1 under stress and to ensure measurement accuracy.

[0056] In this embodiment, the housing 1 is provided with two through holes, which are symmetrically arranged; the through hole on the housing 1 is the housing through hole 101 , and the through hole on the outer cylinder 3 is the outer cylinder 3 through hole 301 .

[0057] Optionally, the inner cylinder 2 includes a first cylindrical portion and a second cylindrical portion, the first cylindrical portion and the second cylindrical portion are integrally connected via a first step portion, the diameter of the first cylindrical portion is greater than the diameter of the second cylindrical portion, the first cylindrical portion and the second cylindrical portion respectively form one end of the inner cylinder 2 and the other end of the inner cylinder 2, and the outer cylinder 3 includes a third cylindrical portion and a fourth cylindrical portion, the third cylindrical portion and the fourth cylindrical portion are integrally connected via a second step portion, the diameter of the third cylindrical portion is greater than the diameter of the fourth cylindrical portion, the third cylindrical portion and the fourth cylindrical portion respectively form one end of the outer cylinder 3 and the other end of the outer cylinder 3, and the second cylindrical portion is partially penetrated into the interior of the fourth cylindrical portion to form the gap.

[0058] Specifically, the outer periphery of the first cylindrical portion is sealedly connected to the inner periphery of one end of the outer shell 1, the outer periphery of the third cylindrical portion is sealedly connected to the inner periphery of the other end of the outer shell 1, the outer peripheries of the cylinders of the two elastomers 4 are respectively sealedly connected to the inner peripheries of the first cylinder and the third cylinder, and the bottom plates of the two elastomers 4 can also be sealedly connected to the first step portion and the second step portion.

[0059] In this embodiment, the sealed connection is achieved by sealing bonding.

[0060] Optionally, the external connection portion includes a conical structure arranged at the center position of one side of the base plate close to the outside of the shell 1, and a mounting hole is arranged at the center position of the conical structure. A part of the strain resistor 401 is located close to the inner wall of the cylinder, and another part of the strain resistor 401 is located close to the wall of the mounting hole.

[0061] Specifically, the mounting hole at the center of the truncated cone structure is used to connect the force, temperature and displacement sensor to an external load device, such as Figure 3 and Figure 4 As shown, when the force, temperature and displacement sensor is under tension, a first cylinder with a hole connected to the mounting hole can be used to facilitate connection with an external load device. When the force, temperature and displacement sensor is under pressure, a second cylinder with a round head can be used, and the round head end portion can be embedded in the mounting hole to achieve a guided connection.

[0062] In this embodiment, a portion of the four strain resistors 401 are disposed close to the projection circle of the inner cylindrical surface of the cylinder on the bottom plate plane, and another portion are disposed at the position of the contour circle of the mounting hole.

[0063] like Figure 5 As shown, the present invention also provides a method for manufacturing a force, temperature and displacement sensor, which is used to manufacture the above-mentioned force, temperature and displacement sensor, comprising:

[0064] A strain resistor 401 is provided on the elastic body 4;

[0065] A capacitor plate 6 is arranged on the outer side of the other end of the inner tube 2 and the inner side of the other end of the outer tube 3, and a temperature measuring device 5 is arranged on the inner side of the other end of the inner tube 2 and the outer side of the other end of the outer tube 3;

[0066] One end of the inner tube 2 is sealedly connected to one end of the outer tube 1, and one end of the outer tube 3 is sealedly connected to the other end of the outer tube 1, so that the other end of the inner tube 2 is movably inserted into the other end of the outer tube 3, and the capacitor plates 6 on the outer side of the inner tube 2 and the inner side of the outer tube 3 correspond to each other;

[0067] The capacitor plate 6, the temperature measuring device 5 and the strain resistor 401 are electrically connected to the processor so that the processor processes the signals of the capacitor plate 6, the temperature measuring device 5 and the strain resistor 401 and outputs displacement, temperature and force signals.

[0068] Specifically, a resistance strain gauge can be pasted on the bottom plate of the elastic body 4 to make the elastic body 4 a force-sensing element, and a temperature-measuring resistor can be pasted on the elastic body 4 to increase its temperature-measuring function; the capacitor plate 6 can be made of copper foil, which is pasted on an insulating film to form a soft capacitor plate 6, and then pasted on the inner tube 2 and the outer tube 3; the temperature-measuring device 5 can be a platinum resistor; coaxial through holes can also be provided on the outer shell 1 and the outer tube 3 for passing the wire 103; the wire 103 connected to the inner tube 2 and the outer tube 3 is led from the inside of the outer shell 1 The wire 103 of the capacitor plate 6 of the inner tube 2 and the wire 103 of the temperature measuring device 5 should have a margin to ensure that the shell 1 is not pulled when the shell 1 is deformed. The wire 103 of the strain resistor 401 is led out of the shell 1, and the wire 103 should have a margin to ensure that the shell 1 is not pulled when the shell 1 is deformed. The through hole passing through the wire 103 can also be sealed to ensure that a closed space is formed inside the shell 1, and a vacuum state can be formed in the sealed space or filled with inert gas or a moisture-absorbing component can be placed, and the inert gas can be nitrogen.

[0069] Optionally, the processor includes a temperature measurement module, a Wheatstone bridge circuit and a capacitor bridge circuit, the temperature measurement module is electrically connected to the temperature measurement device 5, the Wheatstone bridge circuit is electrically connected to the strain resistor 401, and the capacitor bridge circuit is electrically connected to the capacitor plate 6;

[0070] The temperature measuring module processes the signal of the temperature measuring device 5 and outputs a temperature signal;

[0071] The signal of the strain resistor 401 is processed by a Wheatstone bridge circuit, and a force signal is output;

[0072] The capacitor plate 6 signal is processed by a capacitor bridge circuit and a displacement signal is output.

[0073] Specifically, the capacitor plate 6 inside the shell 1 is converted into an electric bridge through a mature adapter circuit arranged in the processor outside the shell 1, and an electrical signal is output after signal processing to represent the initial displacement of the outer cylinder 3 and the inner cylinder 2 along the axial direction. At the same time, the electrical signals output by the strain resistor 401 bridge and the temperature measuring device 5 are obtained to represent the force value and current temperature value of the sensor in the initial state.

[0074] In this embodiment, the measured force, temperature and displacement are calibrated respectively according to the common calibration method of force sensor, temperature sensor and displacement sensor to obtain the standard working curve.

[0075] Specifically, the calibration methods required for force, displacement, and temperature are different, and they need to be calibrated item by item. However, for mass production, an assembly line mode can be adopted to group products and calibrate them separately, which can greatly improve production efficiency and reduce time costs.

[0076] In summary, all the processing and manufacturing methods used in the force, temperature and displacement sensor as a whole are mature and easy. The outer cylinder 3, the inner cylinder 2, the outer shell 1, and the elastomer 4 can all be realized by traditional mechanical processing technology. The raw materials used can be selected from metal materials with good mechanical properties according to specific functional requirements such as rust prevention, elastic modulus, maximum hardness, and yield strength; the elastomer 4 can be made into a force measuring sensitive element by using sputtering film for mechanized and assembly line mass production, or it can be manufactured by using the traditional process of pasting resistance strain gauges; the capacitor plate 6 can also be manufactured by using the sputtering film process or the plate manufacturing process, and can be fixed on the cylindrical surface of the outer cylinder 3 and the inner cylinder 2 by bonding.

[0077] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A force, temperature and displacement sensor, characterized in that: include: An outer shell, wherein the outer shell is an elastic drum-shaped tube; An inner tube and an outer tube, one end of the inner tube is sealedly connected to one end of the outer tube, one end of the outer tube is sealedly connected to the other end of the outer tube, the other end of the inner tube is movably inserted into the inside of the other end of the outer tube to form a gap, a capacitor plate is arranged on the outside of the other end of the inner tube and the inside of the other end of the outer tube, and a temperature measuring device is arranged on the inside of the other end of the inner tube and the outside of the other end of the outer tube; Two elastic bodies, the two elastic bodies are respectively sealed and connected to the inside of one end of the inner cylinder and the inside of one end of the outer cylinder, the elastic body is a cylinder with a bottom plate, a strain resistor is arranged on one side of the bottom plate close to the inside of the shell, and an external connection part is arranged on one side of the bottom plate close to the outside of the shell; A processor is electrically connected to the capacitor plate, the temperature measuring device and the strain resistor.

2. The force, temperature and displacement sensor according to claim 1, characterized in that The processor includes a temperature measurement module, a Wheatstone bridge circuit and a capacitor bridge circuit. The temperature measurement module is electrically connected to the temperature measurement device, the Wheatstone bridge circuit is electrically connected to the strain resistor, and the capacitor bridge circuit is electrically connected to the capacitor plate.

3. The force, temperature and displacement sensor according to claim 1, characterized in that: A closed space is formed in the shell, and the closed space is in a vacuum state or filled with an inert gas or has a moisture absorbing component placed therein.

4. The force, temperature and displacement sensor according to claim 1, characterized in that: The inner peripheral surface of the housing is provided with an annular groove.

5. The force, temperature and displacement sensor according to claim 1, characterized in that: The capacitor plates, the temperature measuring device and the strain resistor are all connected with wires. The shell and the outer cylinder are coaxially provided with through holes, which can accommodate the wires to pass through so that the wires can be led out. A sealing portion is arranged in the through holes.

6. The force, temperature and displacement sensor according to claim 5, characterized in that: The through holes are evenly distributed along the circumference of the shell.

7. The force, temperature and displacement sensor according to claim 1, characterized in that: The inner cylinder includes a first cylindrical portion and a second cylindrical portion, the first cylindrical portion and the second cylindrical portion are integrally connected via a first step portion, the diameter of the first cylindrical portion is greater than the diameter of the second cylindrical portion, the first cylindrical portion and the second cylindrical portion respectively form one end of the inner cylinder and the other end of the inner cylinder, the outer cylinder includes a third cylindrical portion and a fourth cylindrical portion, the third cylindrical portion and the fourth cylindrical portion are integrally connected via a second step portion, the diameter of the third cylindrical portion is greater than the diameter of the fourth cylindrical portion, the third cylindrical portion and the fourth cylindrical portion respectively form one end of the outer cylinder and the other end of the outer cylinder, and the second cylindrical portion is partially penetrated into the interior of the fourth cylindrical portion to form the gap.

8. The force, temperature and displacement sensor according to claim 1, characterized in that: The external connection portion includes a conical structure arranged at the center position of one side of the bottom plate close to the outside of the shell, and a mounting hole is arranged at the center position of the conical structure. A part of the strain resistor is located close to the inner wall of the cylinder, and another part of the strain resistor is located close to the hole wall of the mounting hole.

9. A method for manufacturing a force, temperature and displacement sensor, used for manufacturing the force, temperature and displacement sensor according to any one of claims 1 to 8, characterized in that: include: A strain resistor is arranged on the elastic body; A capacitor plate is arranged on the outer side of the other end of the inner tube and the inner side of the other end of the outer tube, and a temperature measuring device is arranged on the inner side of the other end of the inner tube and the outer side of the other end of the outer tube; One end of the inner tube is sealedly connected to one end of the outer shell, and one end of the outer tube is sealedly connected to the other end of the outer shell, so that the other end of the inner tube is movably inserted into the other end of the outer tube, and the capacitor plates on the outer side of the inner tube and the inner side of the outer tube correspond to each other; The capacitor plates, the temperature measuring device and the strain resistor are electrically connected to a processor so that the processor processes the signals of the capacitor plates, the temperature measuring device and the strain resistor and outputs displacement, temperature and force signals.

10. The method for manufacturing a force, temperature and displacement sensor according to claim 9, characterized in that: The processor includes a temperature measurement module, a Wheatstone bridge circuit and a capacitor bridge circuit, the temperature measurement module is electrically connected to the temperature measurement device, the Wheatstone bridge circuit is electrically connected to the strain resistor, and the capacitor bridge circuit is electrically connected to the capacitor plate; The temperature measuring module processes the signal of the temperature measuring device and outputs the temperature signal; The signal of the strain resistor is processed by a Wheatstone bridge circuit and a force signal is output; The capacitor plate signal is processed by a capacitor bridge circuit and a displacement signal is output.

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