CN116858408A - Shaft force sensor - Google Patents

Abstract

A shaft force sensor, comprising: a metal deformation body, the transverse outer side of the top end of which is provided with a first stress part for receiving a first force, and the transverse inner side of the bottom end of which is provided with a second stress part for receiving a second force; the pressure sensing circuit is arranged on the mounting surface arranged at the top of the deformation body and consists of a plurality of thick film resistors, and the thick film resistors are positioned between the first stress part and the second stress part; the deformation body is provided with a first positioning structure for positioning the force application member of the first force and a second positioning structure for positioning the force application member of the second force. The high-temperature-resistant ceramic can be manufactured through a thick film process, so that the cost can be reduced, the process is simplified, and the temperature resistance is improved.

Description

Shaft force sensor

Technical Field

The application relates to the technical field of force detection, in particular to a shaft force sensor.

Background

Existing axial force sensors are typically sensors that measure axial force by measuring the amount of pressure or strain experienced by an object, as disclosed in CN104204752A, CN101432609a, by placing resistive strain gages on a strain beam or strain gauge; in other applications, including multidimensional force sensors, there are MEMS piezoresistive force sensors in addition to resistive strain gages. CN112857635a also discloses a thick film pressure sensor and a method of making the same, which provides a thick film piezo-resistor on one side of a metal diaphragm to sense the pressure of the fluid on the other side. These axial force sensors are required to be manufactured by complex processes such as bonding, which results in complex processes, high cost, and insufficient high temperature resistance. On the other hand, axial force sensors based on thick film technology have not been proposed so far, nor have such products been found on the market.

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

Disclosure of Invention

Aiming at the defects of the prior art, the application provides a shaft force sensor which is used for reducing the cost, simplifying the process and improving the temperature resistance.

In order to achieve the above purpose, the present application provides the following technical solutions: a shaft force sensor, comprising:

a metal deformation body, the transverse outer side of the top end of which is provided with a first stress part for receiving a first force, and the transverse inner side of the bottom end of which is provided with a second stress part for receiving a second force;

the pressure sensing circuit is arranged on the mounting surface arranged at the top of the deformation body and consists of a plurality of thick film resistors, and the thick film resistors are positioned between the first stress part and the second stress part; the deformation body is provided with a first positioning structure for positioning the force application member of the first force and a second positioning structure for positioning the force application member of the second force.

Preferably, the first force-bearing portion is disposed at a proximal outer edge of the deformation body and the second force-bearing portion is located at or near a bottom end center of the deformation body.

Preferably, the deformation body is circular and the second force receiving portion is located at or near the bottom center of the deformation body, or the deformation body is annular and the second force receiving portion is located near the bottom center of the deformation body.

Preferably, the thick film resistor is disposed on an insulating layer overlying the top surface of the mounting surface.

Preferably, the insulating layer includes island portions corresponding to the thick film resistors one by one and separated from each other, and the thick film resistors are disposed on the island portions one by one.

Preferably, the insulating layer is covered with a protective layer that allows the thick film resistor to be electrically connected to the outside.

Preferably, further comprising: a cover fixed on the top of the deformation body and enclosing an installation cavity with the deformation body; and the circuit board is arranged in the mounting cavity and positioned at one side of the top of the pressure sensing circuit, and the pressure sensing circuit is connected to the circuit board through an electric connecting piece.

Preferably, the top surface of the circuit board is provided with an electronic element, the bottom of the circuit board is fixed on the pressure sensing circuit in an adhesive mode, and the circuit board is provided with a abdication part through which the power supply connecting piece passes to be connected to the top surface of the circuit board.

Preferably, the circuit board is separately secured over the pressure sensing circuit by a support.

Preferably, the top surface of the circuit board is provided with an electronic element, and the circuit board is provided with a abdication part which can be penetrated by the power supply connecting piece to be connected to the top surface of the circuit board.

Preferably, the electrical connector is a flexible circuit board connected to the bottom surface of the circuit board.

Preferably, the shaft force sensor further comprises an electric lead-out assembly penetrating through the cover outwards to connect the circuit board to external equipment, wherein the electric lead-out assembly comprises contact springs, the lower ends of which are respectively abutted on the second bonding pads; the upper end of the contact spring upwards penetrates out of the retaining seat; the holder is penetrated from the cover toward the top side.

Preferably, the contact spring comprises a thin section, a transition section and a thick section which are sequentially connected from top to bottom; the contact spring penetrates through a retaining hole arranged on the retaining seat, and a pressing part for pressing the transition section downwards is formed on the inner wall of the retaining hole; the pressing part presses the bottom end of the contact spring towards one side of the bottom and is connected to the circuit board.

Preferably, a step surface facing to one side of the top is formed on the outer wall of the holding seat, and a first pressing surface is correspondingly formed on the cover, and the first pressing surface presses a third sealing element against the step surface so as to form a seal between the holding seat and the cover; the bottom of the holder holds the circuit board against the lateral extension.

Preferably, the inner wall of the cover is further formed with a second pressing surface, and a fourth sealing piece is arranged between the second pressing surface and the upper ends of the circuit board and the supporting piece.

Drawings

FIG. 1 is a block diagram of a shaft force sensor of a basic embodiment of the present application;

FIG. 2 is a block diagram of a shaft force sensor of a first preferred embodiment of the present application;

FIG. 3 is an exploded view of a second preferred embodiment of the axial force sensor of the present application;

FIG. 4 is a perspective longitudinal cross sectional view of a second preferred embodiment of the present application;

FIG. 5 is a perspective view of a shaft force sensor according to a third preferred embodiment of the present application;

FIGS. 6 and 7 are partial structural perspective views of a shaft force sensor according to a third preferred embodiment of the present application;

FIG. 8 is a perspective longitudinal cross sectional view of a shaft force sensor of a third preferred embodiment of the present application;

FIG. 9 is an exploded view of a fourth preferred embodiment of the present application;

FIG. 10 is a longitudinal cross-sectional view of a fourth preferred embodiment of the present application;

FIG. 11 is a partial view in longitudinal section of a fifth preferred embodiment of the present application;

in the figure: 1. a deformation body; 100. a central bore; 101. a first end face; 102. a first positioning structure; 102a, a step surface; 102b, a trough; 103. a second positioning structure; 103a, protrusions; 103b, a recess; 103c, grooves; 104. a third positioning structure; 105. a mounting surface; 10a, a first stress part; 10b, a second stress part; 2. a support; 201. a longitudinal extension; 202. a lateral extension; 203. a top projection; 204. a relief hole; 205. a locating pin locking hole; 206. a positioning pin; 3. a pressure detection assembly; 300. a pressure sensing circuit; 301. a thick film resistor; 302. a first bonding pad; 303. an insulating layer; 305. a protective layer; 306. a first abdicating part; 307. a flexible circuit board; 308. a positioning pin passing portion; 309. a conductive trace; 310. a circuit board; 311. a relief notch; 311a, yielding gaps; 311b, yielding gaps; 312. a yield window; 313. an electronic component; 314. a second bonding pad; 315. a third bonding pad; 4. a cover; 401. a first pressing surface; 402. a second pressing surface; 41. a barrel; 411. positioning the step; 412. a via hole; 413. a first circumferential positioning portion; 42. a cover plate; 43. an inner cylinder; 5. an electrical outlet assembly; 500. a contact spring; 501. a holding base; 502. a holding hole; 503. a step surface; 504. a thin section; 505. a thick section; 506. a transition section; 507. a tapered end; 508. a second circumferential positioning portion; 901. a first seal; 902. a second seal; 903. a third seal; 904. and a fourth seal.

Detailed Description

The technical solutions of the present application will be clearly and completely described below with reference to the accompanying drawings. The following examples are illustrative only and are not to be construed as limiting the application. In the following description, the same reference numerals are used to designate the same or equivalent elements, and duplicate descriptions are omitted.

In the description of the present application, it should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "inner", "outer", "left", "right", etc. are based on the directions or positional relationships shown in the drawings, or the directions or positional relationships in which the product of the present application is conventionally put in use, or the directions or positional relationships in which those skilled in the art conventionally understand are merely for convenience of describing the present application and for simplifying the description, and are not indicative or implying that the apparatus or element to be referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be construed as limiting the present application.

In addition, the terms "mounted," "connected," "coupled," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present application can be understood as appropriate by those of ordinary skill in the art.

It should be further understood that the term "and/or" as used in the present description and the corresponding claims refers to any and all possible combinations of one or more of the listed items.

As shown in fig. 1, in the basic embodiment of the present application, the axial force sensor includes a deformation body 1 made of metal, the deformation body 1 extending in the lateral direction. The deformation body 1 has a first force receiving portion 10a on one side in the thickness direction (referred to as the longitudinal direction or the axial direction) to which the first force F1 acts, and a second force receiving portion 1b on the other side in the thickness direction to which the first force F1 acts. The shape memory body 1 is made of stainless steel, such as austenite 304, ferrite 430, etc., preferably 17-4PH stainless steel. The first stress-receiving portion 10a and the second stress-receiving portion 10b are offset in a direction perpendicular to the thickness direction (referred to as a lateral direction) of the deformation body 1. In order to make the best use of the lateral dimensions of the deformation body 1, the first stress-receiving portion 10a may be arranged near the outer edge of the deformation body 1, while the second stress-receiving portion 10b is arranged at or near the center of the deformation body 1.

Preferably, the first force F1 is directed downward and the second force F2 is directed upward, such that the top surface of the deformation body 1 forms a tensile stress zone and the bottom surface forms a compressive stress zone. The shape of the deformable body 1 is not particularly limited, and may be rectangular, polygonal, or circular, or may be any other irregular shape. Of course, in order to obtain circumferential symmetry to avoid precisely positioning the thick film resistor 301 in the circumferential direction, the shape of the deformed body 1 may be made circular in the present embodiment. Similarly, the first stress portion 10a may be provided in a ring shape, while the second stress portion 10b is provided in a circular shape.

A pressure sensing assembly is provided in the tensile stress region, the pressure sensing assembly comprising a pressure sensing circuit consisting of a thick film resistor 301. The pressure sensing circuit may be a wheatstone full-bridge circuit composed of two groups of four thick film resistors 301, where the two groups of thick film resistors 301 are disposed at positions (different radial distances) with different stress magnitudes; four thick film resistors 301 are arranged at equal angular intervals around the center of the deformation body 1, and two thick film resistors 301 of each group are provided on opposite sides. Preferably, one group of thick film resistors 301 is located in a region with larger stress, and the other group of thick film resistors 301 is located in a region with smaller stress, so as to obtain more sensitive measurement signals; the region with larger stress is located in the middle portion of the first stress-bearing portion 10a and the second stress-bearing portion 10 b.

In other variant embodiments, only two thick film resistors 301 may be provided and made up into a wheatstone half-bridge circuit; alternatively, two half-bridge circuits are also provided to obtain two measurement signals to form a backup redundancy. It will be appreciated by those skilled in the art that the thick film resistor 301 may be provided as a minimum and that the magnitude of the force may be determined by directly measuring the resistance value thereof and in accordance with the correspondence of the resistance value to the magnitude of the force.

Referring to fig. 2 in combination, the first preferred embodiment differs from the basic embodiment in that a central hole 100 is provided at the center of the deformation body 1, and that the second stress portion 10b is preferably provided to be located in an annular region around the central hole 100. In this way, it is convenient to form a positioning structure for positioning the urging member by using the center hole 100.

Referring to fig. 3 and 4, in a second preferred embodiment of the present application, the axial force sensor includes a deformation body 1 and a cover 4, wherein the cover 4 is fixed on top of the deformation body 1 to form a mounting cavity, and a mounting surface 105 is provided on the top surface of the deformation body 1. A pressure sensing assembly 3 is disposed within the mounting cavity, wherein the pressure sensing assembly 3 includes a pressure sensing circuit disposed on the mounting surface 105. The pressure sensing circuit comprises a plurality of thick film resistors 301, the thick film resistors 301 are arranged on an insulating layer 303 on the mounting surface 105, and first bonding pads 302 used for respectively connecting two ends of the thick film resistors 301 are further arranged on the insulating layer 303. The insulating layer 303 may be made of silicon dioxide, aluminum oxide, etc., and preferably, the insulating layer 303 is covered with a protective layer 305, and the protective layer 305 is provided with a first relief portion 306 to expose a portion of the first pad 302 for power connection. The protective layer 305 may be made of glass enamel or the like. The insulating layer 303 may be configured as a plurality of islands corresponding to the number of the thick film resistors 301 one by one and separated from each other, and the plurality of thick film resistors 301 are disposed on a plurality of isolated portions one by one, so that the resistance of the thick film resistors 301 is prevented from being affected by the transverse transmission of stress by the insulating layer.

The pressure detecting assembly 3 further comprises a circuit board 310 located on the top side of the protective layer 305, which may be provided on the support 2 on the deformation body 1 to be longitudinally separated from the pressure sensing circuit, or the bottom surface of the circuit board 310 may be directly fixed to the top surface of the protective layer 305 by bonding. The top surface of the circuit board 310 is provided with an electronic element 313, a plurality of second pads 314, and a plurality of third pads (not shown). An electrical outlet assembly 5 is connected to the second pad 314 to power the circuit board 310 and output a measurement signal to the outside. The circuit board 310 is provided with a yielding notch 311 and a yielding window 312 for yielding a portion of the first bonding pad 302, and the portion of the first bonding pad 302 is connected to a third bonding pad on the circuit board 310 through electrical connectors such as wires and leads. The electrical outlet assembly 5 may be, among other things, a wire, cable, conductive connector, etc., for connecting to an external device. The electrical outlet assembly 5 may be threaded out of the side or top of the housing 4, in particular to the present embodiment, through a via 412 formed in the side of a part of the housing 4, the gap between the via 412 and the electrical outlet assembly 5 being sealed by a first seal 901. The cover 4 includes a cylinder 41 having an upper and lower opening and a cover plate 42 covering the top of the cylinder 41, and the cover plate 42 is positionally provided on a positioning step 411 provided on the inner edge of the top of the cylinder 41 and is fixed to the cylinder 41 by welding, bonding or the like.

Preferably, the deformation body 1 is formed with a first positioning structure 102 for positioning the force application member of the first force F1, a second positioning structure 103 for positioning the force application member of the second force F2, and a third positioning structure 104 for positioning the support member 2. The first force receiving portion 10a may be all or only a portion of a contact surface of the first positioning structure 102 with the force application member of the first force F1 in the longitudinal direction, and the second force receiving portion 10b may be all or only a portion of a contact surface of the second positioning structure 103 with the force application member of the second force F2 in the longitudinal direction. The first positioning structure 102, the second positioning structure 103, the third positioning structure 104 may be at least one step surface, or at least one groove, or a combination thereof. In this embodiment, the first positioning structure 102 and the third positioning structure 104 are step surfaces, and the second positioning structure 103 includes a downward protrusion and a step surface formed around the protrusion. The second force F2 acts on the bottom surface of the second positioning structure 103, and the second force receiving portion 10b is disposed on the bottom surface (may be a plane, a curved surface, or other irregular surface) of the second positioning structure 103. The first stress portion 10a is disposed on the step surface of the first positioning structure 102. The support 2 includes a longitudinal extension 201 and a lateral extension 202 formed by extending an upper end of the longitudinal extension 201 toward an inner side. Wherein the circuit board 310 is adhered to the top surface of the lateral extension 202 or the inner wall of the barrel 41 is formed with a downward facing step surface that presses the circuit board 310 down against the lateral extension 202. Wherein a relief hole 204 is formed in the middle of the lateral extension 202 to give way to the electrical connector. The longitudinal extension 201 is supported on the stepped surface of the third positioning structure 104 and can additionally be fastened to the deformation body 1 by means of a tight fit, adhesive bonding or welding.

Referring to fig. 5 to 8, in comparison with the second preferred embodiment, the third preferred embodiment shows a variation of the annular shaped deformation body 1, i.e. the central hole 100 is provided in the middle of the deformation body 1. In contrast to the second preferred embodiment, the cover 4 includes, in addition to the cylinder 41, the cover plate 42, an inner cylinder 43 extending downward from the inner edge of the cover plate 42. The inner cylinder 43 is tightly fitted in the central hole 100 and/or its lower end is further connected to an upwardly disposed stepped surface formed on the inner wall of the central hole 100 by welding or the like. The inner tube 43 and the center hole 100 are sealed by a second seal 902, and the second seal 902 is disposed in a seal groove provided on the inner wall of the center hole 100. The electrical outlet assembly 5 extends upwardly from the cover plate 42 for connection to an external device. The second positioning structure 103 includes a recess 103b recessed inward from the periphery of the lower end of the central hole 100, and a protrusion 103a protruding downward from the outer side of the recess 103 b. Preferably, the bottom surface of the deformation body 1 is formed with a groove 103c outside the protrusion 103a, so that the rigidity of the deformation body 1 can be reduced to some extent to improve the measurement sensitivity. In this embodiment, the yielding gap includes a yielding gap 311a formed at an inner edge of the circuit board 310 and a yielding gap 311b formed at an outer edge of the yielding gap 311, and the yielding gap 311a and the yielding gap 311 are staggered in a circumferential direction, so that the first stress portion 10a and the second stress portion 10b are staggered in a lateral direction while maintaining a smaller lateral dimension.

Please refer to fig. 9 to 10. A fourth preferred embodiment of the present application shows a shaft force sensor with a specially configured electrical lead out assembly 5. The axial force sensor comprises a deformation body 1 made of metal. The deformation body 1 is provided with a first force receiving portion 10a on one side in the axial direction for the first force F1 to act on, and a second force receiving portion on the other side in the axial direction for the first force F1 to act on. The first stress portion 10a and the second stress portion are laterally offset. Specifically, the first stress portion 10a is provided at a position near the edge of the deformation body 1 in the shape of a ring, while the second stress portion is provided in the central region of the deformation body 1 in the shape of a circle. The second positioning structure 103 includes a recess 103b at the center of the lower end of the deformation body 1 and a protrusion 103a formed by protruding downward with respect to the outer side of the recess 103 b. Preferably, the bottom surface of the deformation body 1 is formed with a groove 103c outside the protrusion 103a, so that the rigidity of the deformation body 1 can be reduced to some extent to improve the measurement sensitivity.

Preferably, the deformation body 1 is formed with a first positioning structure 102 for positioning the force application member of the first force F1, a second positioning structure 103 for positioning the force application member of the second force F2, and a third positioning structure 104 for positioning the support member 2. The first positioning structure 102, the second positioning structure 103, the third positioning structure 104 may be at least one step surface, or at least one groove, or a combination thereof. In this embodiment, the third positioning structure 104 is a step surface, where the second positioning structure 103 includes a concave portion 103b recessed inward from the periphery of the lower end of the central hole 100 and a protrusion 103a formed by protruding downward from the outer side of the concave portion 103 b; the first positioning structure 102 includes a step surface 102a and an annular groove 102b disposed radially inward of the step surface 102 a. The bottom surface of the variation 1 is formed with a groove 103c outside the protrusion 103a, so that the rigidity of the variation 1 can be reduced to some extent to improve the measurement sensitivity. The second force F2 acts on the bottom surface of the second positioning structure 103, and the second force receiving portion 10b is disposed on the bottom surface (may be a plane, a curved surface, or other irregular surface) of the second positioning structure 103. The first stress portion 10a is disposed on the step surface of the first positioning structure 102. In other embodiments, the second stress portion 10b may be disposed on only a portion of the bottom surface of the second positioning structure 103, for example, only the bottom surface of the protrusion 103a.

The axial force sensor further comprises a cover 4, the cover 4 being fixed on top of the deformation body 1 to enclose a mounting cavity together with the deformation body 1, the top surface of the deformation body 1 being provided with a mounting surface 105. A pressure sensing assembly 3 is disposed within the mounting cavity, wherein the pressure sensing assembly 3 includes a pressure sensing circuit disposed on the mounting surface 105. The pressure sensing circuit comprises a plurality of thick film resistors 301, the thick film resistors 301 are arranged on an insulating layer 303 on the mounting surface 105, and first bonding pads 302 used for respectively connecting two ends of the thick film resistors 301 are further arranged on the insulating layer 303. The insulating layer is further provided with a conductive trace 309, and the conductive trace 309 is connected to two ends of the thick film resistor 301 to form the pressure sensing circuit 300. The insulating layer 303 may be made of silicon dioxide, aluminum oxide, or the like. The surface of the insulating layer 303 may be covered with a protective layer (not shown).

The pressure detection assembly 3 further comprises a circuit board 310, which is located on the top side of the protective layer 305, in particular on the support 2 on the deformation body 1. The bottom surface of the circuit board 310 is provided with an electronic component 313 and a plurality of third pads 315, and the top surface of the circuit board 310 is provided with a plurality of second pads 314. The electrical outlet assembly 5 is connected to the second pad 314 to supply power to the circuit board 310 and output a measurement signal to the outside. The conductive trace 309 is connected to a third pad 315 on the bottom surface of the circuit board 310 through an electrical connection (specifically, the flexible circuit board 307), so as to process and output the signal measured by the pressure sensing circuit 300.

The support 2 includes a longitudinal extension 201 and a lateral extension 202 formed by extending an upper end of the longitudinal extension 201 toward an inner side, wherein a yielding hole 204 for yielding the electrical connector is formed in a middle portion of the lateral extension 202. The upper end of the longitudinal extension 201 also protrudes upward to form a top protrusion 203, and the circuit board 310 is supported on the lateral extension 202 and is circumferentially positioned by the top protrusion 203.

The electrical outlet assembly 5 is used for connecting an external device, and comprises a plurality of contact springs 500 with lower ends respectively abutting against the second bonding pad 314 and a holding seat 501 for holding the contact springs 500, wherein the upper ends of the contact springs 500 penetrate upwards from the holding seat 501. The holder 501 protrudes upwardly from the cartridge 41. The contact spring 500 includes a thin section 504, a transition section 506, and a thick section 505 sequentially connected from top to bottom. The outer contour of the transition section 506 may be tapered. The contact spring 500 is passed through a holding hole 502 provided on the holding seat 501, and an abutment portion such as a stepped surface or a tapered surface for pressing down the transition section 506 is formed on the inner wall of the holding hole 502 to press down the lower end of the contact spring 500 against the second pad 314. Wherein, the thick section 505 is mainly used for keeping elastic contact, and the coiling is sparse, namely the pitch can be set larger; the thin section 504 is mainly used for connection with an external arrangement, and the transition section 506 is mainly used for abutment with the abutment portion of the holder 501, so that the winding thereof is tight, i.e. the pitch can be set smaller. Preferably, the upper end of the thin section 504 may also be provided with a tapered end 507 to facilitate plugging into an external device. Preferably, the lateral extension 202 is provided with a positioning pin locking hole 205, the circuit board 310 is provided with a positioning pin passing portion 308 such as a hole or a notch, and the lower end of at least one positioning pin 206 is penetrated downwards through the positioning pin passing portion 308 and locked in the positioning pin locking hole 205, so as to fix the circuit board 310 on the support 2.

An upward step surface 503 is formed on the outer wall of the holder 501, and a first pressing surface 401 is correspondingly formed on the cover 4, and the positioning step 411 presses a third seal 903 against the step surface 503, so that a seal is formed between the holder 501 and the cover 4. The bottom of the holder 501 abuts the circuit board 310 against the lateral extension 202. In order to facilitate the circumferential positioning between the holder 501 and the cover 4, a first circumferential positioning portion 413 is provided on the inner wall of the cover 4, and a second circumferential positioning portion 508 that is cooperatively connected with the first circumferential positioning portion 413 is correspondingly provided on the outer wall of the holder 501. The first circumferential positioning portion 413 and the second circumferential positioning portion 508 may have a flat structure, or one may be a longitudinally extending protrusion and the other may be a groove in mating connection with the protrusion. In other embodiments, the electrical outlet assembly 5 may also be a wire, cable, conductive connector, or the like.

Referring to fig. 11, the axial force sensor according to the fifth embodiment of the present application is different from the fourth preferred embodiment in that a second pressing surface 402 is further formed on the inner wall of the housing 4, and a fourth sealing member 904 is disposed between the second pressing surface 402 and the upper ends of the circuit board 310 and the supporting member 2. Therefore, the tightness of the mounting cavity can be improved through double sealing, and the service life of the electronic element is prolonged.

In the above examples, it can be understood that the thick film resistor 301 may be replaced with a strain gauge such as a resistance strain gauge or a silicon micro-fuse strain gauge to obtain an embodiment of the relatively deteriorated axial force sensor.

The scope of the present disclosure is defined not by the detailed description but by the claims and their equivalents, and all modifications within the scope of the claims and their equivalents are to be construed as being included in the present disclosure.

Claims (15)

1. A shaft force sensor, comprising:

a metal deformation body (1) having a first force receiving portion (10 a) for receiving a first force (F1) provided on the outer side in the lateral direction of the top end and a second force receiving portion (10 b) for receiving a second force (F2) provided on the inner side in the lateral direction of the bottom end;

the pressure sensing circuit is arranged on the mounting surface (105) arranged at the top of the deformation body (1) and consists of a plurality of thick film resistors (301), and the thick film resistors (301) are positioned between the first stress part (10 a) and the second stress part (10 b); the deformation body (1) is formed with a first positioning structure (102) for positioning the force application member of the first force (F1), and a second positioning structure (103) for positioning the force application member of the second force (F2).

2. The axial force sensor of claim 1, wherein the first force-bearing portion (10 a) is disposed at a proximal outer edge of the deformation body (1), and the second force-bearing portion (10 b) is located at or near a bottom center of the deformation body (1).

3. The axial force sensor of claim 2, wherein the deformation body (1) is circular and the second force receiving portion (10 b) is located at or near the bottom center of the deformation body (1), or wherein the deformation body (1) is annular and the second force receiving portion (10 b) is located near the bottom center of the deformation body (1).

4. The axial force sensor of claim 1, wherein the thick film resistor (301) is disposed on an insulating layer (303) overlying a top surface of the mounting surface (105).

5. The axial force sensor of claim 4, wherein the insulating layer (303) comprises islands that are in one-to-one correspondence with and separate from the plurality of thick film resistors (301), the thick film resistors (301) being disposed on the islands in one-to-one correspondence.

6. The axial force sensor of claim 5, wherein the insulating layer (303) is covered with a protective layer (305) that allows the thick film resistor (301) to be electrically connected to the outside.

7. The axial force sensor of claim 1, further comprising:

a cover (4) fixed on the top of the deformation body (1) and enclosing an installation cavity with the deformation body;

and a circuit board (310) disposed within the mounting cavity and on a top side of the pressure sensing circuit, the pressure sensing circuit being connected to the circuit board (310) by an electrical connection.

8. The axial force sensor of claim 7, wherein the top surface of the circuit board (310) is provided with electronic components, the bottom of the circuit board (310) is fixed to the pressure sensing circuit by bonding, and the circuit board (310) is provided with a relief portion through which the power supply connector passes to connect to the top surface of the circuit board (310).

9. The axial force sensor of claim 7, wherein the circuit board (310) is detachably secured above the pressure sensing circuit by a support (2).

10. The axial force sensor of claim 7, wherein the top surface of the circuit board (310) is provided with electronic components, and wherein the circuit board (310) is provided with a relief portion through which the power connection member passes to connect to the top surface of the circuit board (310).

11. The axial force sensor of claim 10, wherein the electrical connection is a flexible circuit board (307), the flexible circuit board (307) being connected to a bottom surface of the circuit board (310).

12. The axial force sensor of any one of claims 7-11, further comprising an electrical outlet assembly (5) that extends outwardly through the cover (4) to connect the circuit board (310) to an external device, the electrical outlet assembly (5) comprising:

contact springs (500) with lower ends respectively abutting against the second bonding pads (314);

and a holder (501) for holding the contact spring (500), the upper end of the contact spring (500) being passed upward from the holder (501); the holder (501) is extended from the cover (4) toward the top side.

13. The axial force sensor of claim 12, wherein the contact spring (500) comprises a thin section (504), a transition section (506), and a thick section (505) connected in sequence from top to bottom; the contact spring (500) penetrates through a retaining hole (502) arranged on the retaining seat (501), and a pressing part for pressing the transition section (506) downwards is formed on the inner wall of the retaining hole (502); the pressing part presses the bottom end of the contact spring (500) towards one side of the bottom and is connected to the circuit board (310).

14. The axial force sensor of claim 12, wherein a step surface (503) facing the top is formed on the outer wall of the holder (501), and a first pressing surface (401) is formed on the cover (4) correspondingly, and the first pressing surface (401) presses a third seal (903) against the step surface (503) to form a seal between the holder (501) and the cover (4); the bottom of the holder (501) abuts the circuit board (310) against the lateral extension (202).

15. The axial force sensor of claim 14, wherein the inner wall of the cover (4) is further formed with a second pressing surface (402), and a fourth sealing member (904) is provided between the second pressing surface (402) and the upper ends of the circuit board (310) and the support member (2).