CN220751418U - Force sensor - Google Patents

Abstract

The present utility model relates to a low cost force sensor comprising: the device comprises a pressure sensitive part, a spherical force transmission element, a shell and a supporting structure or a supporting part arranged at the lower part of the shell, wherein the supporting structure or the supporting part is suitable for stabilizing and supporting the pressure sensitive part, a positioning structure with a preset depth or length is arranged inside the shell, the positioning structure is suitable for encircling the spherical force transmission element right above a sensitive end of the pressure sensitive part, and the positioning structure is in movable fit with a spherical diameter part of the spherical force transmission element, the depth or the length of the positioning structure is suitable for moving the spherical diameter part of the spherical force transmission element towards the direction of the pressure sensitive part in a preset distance in a movable fit manner, an opening is arranged at the upper end of the shell, the spherical force transmission element extends from the opening to the preset distance outside the shell, the opening is smaller than the spherical diameter of the spherical force transmission element, and the edge of the opening is away from the preset distance of the spherical force transmission element.

Description

Force sensor

Technical Field

The utility model relates to a force sensor, in particular to a low-cost force sensor formed by pressure sensitive components, belonging to the technical field of sensors.

Background

Along with the improvement of living requirements of people, the application of the sensor is more and more extensive, wherein the force sensor is applied to the fields of medical treatment, consumer electronics and industry, but the current force sensor has the defects of complex structure, high cost, poor repeatability, low detection precision, poor mass manufacturing consistency and the like.

Disclosure of Invention

The utility model aims to provide the force sensor which has the advantages of simple structure, easy assembly, low cost, good consistency of products manufactured in batches, short response time, stable output signal and high sensitivity and precision.

The utility model is realized by the following technical scheme: a force sensor, comprising: the device comprises a pressure sensitive part, a spherical force transmission element, a shell and a supporting structure or a supporting part arranged at the lower part of the shell, wherein the supporting structure or the supporting part is suitable for stabilizing and supporting the pressure sensitive part, a positioning structure with a preset depth or length is arranged inside the shell, the positioning structure is suitable for encircling the spherical force transmission element right above the sensitive end of the pressure sensitive part, and the positioning structure is in movable fit with the spherical diameter part of the spherical force transmission element, the depth or the length of the positioning structure is suitable for moving the spherical diameter part of the spherical force transmission element towards the direction of the pressure sensitive part in a preset distance, an opening is arranged at the upper end of the shell, the spherical force transmission element extends from the opening to the outside of the shell for a preset distance, the opening is smaller than the spherical diameter of the spherical force transmission element, and the edge of the opening is a preset distance from the spherical force transmission element.

The method comprises the following steps: the positioning structure is a hole provided with a predetermined depth or length, in which hole the spherical force transmitting element is arranged. The hole comprises: round holes, toothed round holes, regular triangle holes, square holes, regular polygon holes, diamond holes.

In one embodiment, the pressure sensitive component comprises: a circular ceramic pressure sensitive diaphragm, or a circular ceramic pressure sensitive core with a concave middle part, or a cylindrical ceramic pressure sensitive core, or one of silicon film pressure sensitive chips.

In another embodiment, the housing comprises: the shell and the cover of mutual fixed connection, the opening is circular opening, location structure set up on the cover, be equipped with the ring shape brace table on the inner wall of shell, ceramic pressure sensitive part arranges on the ring shape brace table.

In another embodiment, the housing comprises: the ceramic pressure sensitive component comprises a shell and a circular supporting part which are fixedly connected with each other, wherein the opening is a circular opening, the circular opening and the positioning structure are arranged on the shell, and the ceramic pressure sensitive component is arranged on the circular supporting part.

In another embodiment, the housing comprises: the silicon film pressure sensitive chip is arranged on the substrate.

In another embodiment, the housing comprises: the shell and the cover of mutual fixed connection, the opening is circular opening, location structure set up on covering, be equipped with the ring shape brace table on the inner wall of shell, silicon film pressure sensitive chip arranges on circular shape PCB circuit board, circular shape PCB circuit board is put on the ring shape brace table.

The beneficial effects of the utility model are as follows: the structure is simple, the cost is low, the manufacture or the assembly is easy, the sensitivity is high, the repeated detection precision is high, the problem that the spherical force transmission element is unstable in output signals caused by shaking when the spherical force transmission element is connected with external input force or in the detection process is reduced, and the dynamic response performance of the force sensor is improved.

Drawings

FIG. 1 is a schematic cross-sectional structural view of a force sensor of the present utility model;

FIG. 2 is a schematic cross-sectional view of another force sensor of the present utility model;

FIG. 3 is a schematic cross-sectional view of section A-A of FIG. 2;

FIG. 4 is a schematic cross-sectional view of another force sensor of the present utility model;

FIG. 5 is a schematic cross-sectional view of section B-B of FIG. 4;

FIG. 6 is a schematic cross-sectional view of another force sensor of the present utility model.

Detailed Description

The following description of the preferred embodiments will be given by way of example with reference to the accompanying drawings. For simplicity of description, in the following examples, like reference numerals indicate functionally or functionally equivalent structures.

FIG. 1 is a schematic cross-sectional view of a force sensor of the present utility model, and in particular a force sensor comprised of ceramic pressure sensitive diaphragms. It comprises the following steps: a cup-shaped shell 11, a round convex cover 12, a round ceramic pressure sensitive membrane 13, a spherical force transmission element 14, the shell 11 and the cover 12 forming a housing according to the utility model; a strain resistance bridge or a temperature compensation circuit is usually provided on the back or under the circular ceramic pressure sensitive diaphragm 13, but is not limited thereto; wherein, a circular supporting table A is arranged in the shell 11, and a circular ceramic pressure sensitive membrane 13 is stably arranged on the supporting table A; a round hole K with a preset depth or length La is arranged in the cover 12, a hole wall B of the round hole K is suitable for circumscribing the spherical force transmission element 14 right above the round ceramic pressure sensitive membrane 13, the hole wall B of the round hole K is in movable fit with a spherical diameter part D of the spherical force transmission element 14, the depth or length La of the round hole K is suitable for moving the spherical diameter part D of the spherical force transmission element 14 towards the ceramic pressure sensitive membrane 13 by a preset distance Lb in a movable fit manner, namely when an external input force F=0, the spherical diameter part D of the spherical force transmission element 14 is in movable fit with the hole wall B; when the external input force f=rated value, the spherical diameter portion D of the spherical force transmission element 14 still keeps the movable fit with the hole wall B, and at this time, the movement distance of the spherical force transmission element 14 is Lb; the round hole K with the preset depth or length La and the hole wall B form the positioning structure of the utility model; at the upper end of the cap 12 there is provided a circular opening C from which the spherical force transmitting element 14 extends to a predetermined distance Lc outside the cap 12, the aperture D of the circular opening C being smaller than the spherical diameter D of the spherical force transmitting member, and the edge E of the circular opening C being a predetermined distance (D-D)/2 from the spherical force transmitting element 14; the spherical force transmitting element 14 is not always in contact with the edge E of the circular opening C when the external input force F increases from zero to a predetermined value; when the force sensor is inverted, the spherical force transmission member 14 does not come off the case 11 and the cover 12. Where 15 is the wire guide provided on the housing 11 and 16 is the wire connected to the electrical input/output of the ceramic pressure sensitive diaphragm 13.

As can be seen from fig. 1, when the force sensor detects the force F, the shake generated by the spherical force transmission element 14 relative to the ceramic pressure sensitive membrane 13 can be controlled by the clearance between the spherical diameter portion of the spherical force transmission member 14 and the hole wall B, so that, on the premise of ensuring the moving fit, in order to reduce the shake or movement generated by the spherical force transmission element 14 relative to the ceramic pressure sensitive membrane 13 when the spherical force transmission element 14 receives the predetermined input force F, the detection precision is improved or the repeated detection error is reduced, the clearance between the spherical diameter portion D of the spherical force transmission member 14 and the hole wall B should be set to a reasonable minimum value, or other technical means are adopted to reduce the friction coefficient or friction force between the spherical force transmission member 14 and the hole wall B, which is beneficial to improving the sensitivity of the force sensor.

Fig. 2 and 3 are schematic cross-sectional structural views of another force sensor of the present utility model, particularly a force sensor comprised of a concave ceramic pressure sensitive core. It comprises the following steps: a cylindrical shell 21, a round convex cover 22, a round ceramic pressure sensitive core 23 with a concave middle part, a spherical force transmission element 24, wherein the shell 21 and the cover 22 form a shell according to the utility model; a strain resistance bridge or a temperature compensation circuit is generally arranged at the back or lower surface of the ceramic pressure sensitive core 23 at the middle part of the circle, but is not limited to the above; wherein, a circular supporting table A for supporting the ceramic pressure sensitive core 23 is arranged in the shell 21, and the ceramic pressure sensitive core 23 and the inner wall of the shell 21 form a stable matching structure; in the cover 22, a hole K of a predetermined depth or length La is provided, the wall B of which is toothed as shown by B in fig. 3; the hole wall B of the hole K is suitable for circumscribing the spherical force transmission element 24 right above the ceramic pressure sensitive core 23, the hole wall B of the hole K is in movable fit with the spherical diameter part D of the spherical force transmission element 24, the depth or length La of the hole K is suitable for moving the spherical diameter part D of the spherical force transmission element 24 towards the ceramic pressure sensitive core 23 by a preset distance Lb in a movable fit manner, namely when an external input force F=0, the spherical diameter part D of the spherical force transmission element 24 is in movable fit with the hole wall B; when the external input force f=rated value, the spherical diameter portion D of the spherical force transmission element 24 still keeps the movable fit with the hole wall B, and at this time, the moving distance of the spherical force transmission element 24 is Lb; the hole K and the hole wall B with the preset depth or length La form a positioning structure of the utility model; at the upper end of the cover 22 a circular opening C is provided, the aperture of which opening C is D, from which circular opening C the spherical force transmitting element 24 extends to a predetermined distance Lc outside the cover 22, the aperture D of which circular opening C is smaller than the spherical diameter D of the spherical force transmitting member, and the circular opening edge E is at a predetermined distance (D-D)/2 from the spherical force transmitting element 24, i.e. when the external input force F increases from zero to a predetermined value, said spherical force transmitting element 24 will not always contact the edge E of the circular opening C, and when the force sensor is inverted the spherical force transmitting member 24 will not disengage from the housing 21 and the cover 22. Where 25 is the wire guide provided on the housing 21 and 26 is the wire connected to the electrical input/output of the ceramic pressure sensitive core 23.

As can be seen from fig. 2 and 3, in the force sensor according to the present utility model, during the process of detecting the force F, the spherical force transmission element 24 generates less shake relative to the central concave circular ceramic pressure sensitive core 23, or the generated shake can be controlled by setting the gap between the spherical diameter portion of the spherical force transmission element 24 and the hole wall B, and generally, the smaller the gap between the spherical diameter portion of the spherical force transmission element 24 and the hole wall B is, the better the smaller the clearance is under the premise of ensuring the movable fit. In addition, it should be appreciated that in fig. 2 and 3, the detection sensitivity of this embodiment is higher than that of fig. 1 because the movable fit contact area between the spherical force transmission member 24 and the hole wall B is reduced by the circular hole positioning K in which the wall B is toothed. Similarly, the improved sensitivity of the force sensor may be facilitated by improving the finish of the spherical force transfer member 24 and the aperture wall B, or by reducing the coefficient of friction or frictional force between the spherical force transfer member 24 and the aperture wall B by other means.

Fig. 4 and 5 are schematic cross-sectional structural views of another force sensor of the present utility model, particularly a force sensor comprised of a cylindrical ceramic pressure sensitive core. It comprises the following steps: an inverted cup-shaped shell 41 with a stepped step on the inner wall, a circular ring-shaped supporting part 42, a cylindrical ceramic pressure sensitive core 43, a spherical force transmission element 44, wherein the shell 41 and the circular ring-shaped supporting part 42 form the shell; a strain resistance bridge or temperature compensation circuit is typically provided on the back or under the cylindrical ceramic pressure sensitive core 43; however, a strain resistance bridge or temperature compensation circuit may be provided on or over the front side of the ceramic pressure sensitive core 43; wherein, the upper end surface A of the annular supporting part 42 is suitable for supporting a cylindrical ceramic pressure sensitive core 43, and the cylindrical ceramic pressure sensitive core 43 and the inner wall of the shell 41 form a stable matching structure; the annular supporting portion 42 is coupled to the housing 41 by screw-fitting, but is not limited thereto; a square hole K of a predetermined depth or length La is provided in the casing 41, the hole wall B of the square hole K being adapted to trap the spherical force transmission element 44 directly above the cylindrical ceramic pressure sensitive core 43, the hole wall B of the square hole K being in a movable fit with the spherical diameter portion D of the spherical force transmission element 44, the depth or length La of the square hole K being adapted to move the spherical diameter portion D of the spherical force transmission element 44 toward the ceramic pressure sensitive core 43 by a predetermined distance Lb in a movable fit, i.e. when an external input force f=0, the movable fit is maintained between the spherical diameter portion D of the spherical force transmission element 44 and the hole wall B; when the external input force f=rated value, the spherical diameter portion D of the spherical force transmitting element 44 still maintains a movable fit with the inner wall B, and at this time, the movement distance of the spherical force transmitting element 44 is Lb; the square hole K with the preset depth or length La and the hole wall B form the positioning structure of the utility model; the positioning structure can be arranged on a separate component to form the positioning component of the utility model; at the upper end of the housing 41 a circular opening C is provided, the aperture of which opening C is D, from which circular opening C the spherical force transmitting element 44 extends to a predetermined distance Lc outside the housing 41, the aperture D of which circular opening C is smaller than the spherical diameter D of the spherical force transmitting member, and the circular opening edge E is at a predetermined distance (D-D)/2 from the spherical force transmitting element 44, i.e. when the external input force F increases from zero to a predetermined value, said spherical force transmitting element 44 always does not contact the edge E of the circular opening C, and when the force sensor is inverted the spherical force transmitting member 44 does not disengage from the housing 41 and the bottom cover 42. Where 45 is the through hole provided in the housing 41 and 46 is a wire connected to the electrical input/output of the cylindrical ceramic pressure sensitive core 43.

As can be seen from fig. 4 and 5, in the force sensor according to the present utility model, during the process of detecting the force F, the shake or movement of the spherical force transmission element 44 relative to the cylindrical ceramic pressure sensitive core 43 can be controlled by providing a gap between the spherical diameter portion D of the spherical force transmission element 44 and the hole wall B, and generally, the smaller the gap between the spherical diameter portion D of the spherical force transmission element 44 and the hole wall B is, the better the smaller the clearance is under the premise of ensuring the movable fit. It should be appreciated that in fig. 4 and 5, the square positioning hole K is used, so that the area of the movable contact between the spherical force transmission member 44 and the hole wall B is small or the movable contact area is a point contact, and therefore, the sensitivity or detection accuracy of this embodiment is higher than that of the embodiment of fig. 1 and 2.

FIG. 6 is a schematic cross-sectional view of another force sensor of the present utility model, particularly a force sensor formed from a silicon thin film pressure sensitive die. It comprises the following steps: the PCB circuit board 61, the circular or square cover 62, the silicon thin film pressure sensitive chip 63, the spherical force transmission element 64, the case 61 and the cover 62 constitute a case according to the present utility model; the PCB circuit board 61 is adapted to locate the circular or square cover 62 and the sinking groove of the silicon film pressure sensitive chip 63, the 64 is an air pressure balance hole, the 65 is a wire electrically connecting the silicon film pressure sensitive chip 63 and the PCB circuit board 61, and the silicon film pressure sensitive chip 63 and the circular or square cover 62 are fixedly connected to the PCB circuit board 61 by an adhesive or other suitable means. A round hole K with a preset depth or length La is arranged in the round or square cover 62, the hole wall B of the round hole K is suitable for circumscribing the spherical force transmission element 64 right above the silicon film pressure sensitive chip 63, the hole wall B of the round hole K is in movable fit with the spherical diameter part D of the spherical force transmission element 64, the depth or length La of the round hole K is suitable for moving the spherical diameter part D of the spherical force transmission element 64 towards the silicon film pressure sensitive chip 63 by a preset distance Lb in a movable fit manner, namely when an external input force F=0, the spherical diameter part D of the spherical force transmission element 64 is kept in movable fit with the hole wall B; when the external input force f=the rated value, the spherical diameter portion D of the spherical force transmitting element 64 still keeps the movable fit with the hole wall B, and at this time, the moving distance of the spherical force transmitting element 64 is Lb; the round hole K with the preset depth or length La and the hole wall B form the positioning structure of the utility model; at the upper end of the circular or square cap 62 there is provided a circular opening C from which the spherical force transmitting element 64 extends to a predetermined distance Lc outside the cap 62, the aperture D of the circular opening C being smaller than the spherical diameter D of the spherical force transmitting member 64, and the edge E of the circular opening C being a predetermined distance (D-D)/2 from the spherical force transmitting element 64; the spherical force transfer element 64 is not always in contact with the edge E of the circular opening C when the external input force F increases from zero to a predetermined value; when the force sensor is inverted, the spherical force transfer member 64 does not come off the cover 62. In addition, it is contemplated that the PCB 61 may be replaced with a substrate with conductive terminals or pins, i.e., the PCB 61 is but one embodiment of the substrate of the present utility model.

As can be seen from fig. 6, when the force sensor detects the force F, the shake generated by the spherical force transmission element 64 relative to the silicon thin film pressure sensitive chip 63 can be controlled by the clearance between the spherical diameter portion of the spherical force transmission member 64 and the hole wall B, so that, on the premise of ensuring the moving fit, in order to reduce the shake or movement generated by the spherical force transmission element 64 relative to the silicon thin film pressure sensitive chip 63 when the spherical force transmission element 64 receives the predetermined input force F, the detection precision is improved or the repeated detection error is reduced, the clearance between the spherical diameter portion of the spherical force transmission member 64 and the hole wall B should be set to a reasonable minimum value, or other technical means are adopted to reduce the friction coefficient or friction force between the spherical force transmission member 64 and the hole wall B, which is beneficial to improving the sensitivity or precision of the force sensor; while attention should be paid to improving the dimensional accuracy of the shape, surface finish, of the bore wall B, spherical force transfer element 64. Similarly, it should be understood that the round hole K in fig. 6 may be a toothed round hole, a regular triangle hole, a square hole, a regular polygon, a diamond hole, or the like.

It is contemplated that in the embodiment of fig. 6, the circular ceramic pressure sensitive membrane 13 may be replaced with the PCB circuit board 61 and the silicon thin film pressure sensitive chip 63 of fig. 6, where the PCB circuit board 61 is circular, so that fig. 1 may form a housing comprising: the shell and the cover of mutual fixed connection, the opening is circular opening, location structure set up on covering, be equipped with the ring shape brace table on the inner wall of shell, silicon film pressure sensitive chip arranges on circular shape PCB circuit board, circular shape PCB circuit board is put the force transducer on the ring shape brace table.

It should be understood that in the embodiment of fig. 1-6, the ceramic pressure sensitive diaphragm or core or silicon thin film pressure sensitive chip, spherical force transfer element is arranged coaxially, such that the aperture, circular opening of the positioning structure is also arranged coaxially with the ceramic pressure sensitive diaphragm or core or silicon thin film pressure sensitive chip, spherical force transfer element.

The shell, the cover, the bottom cover, the spherical force transmission element, the shell and the like can be made of metal materials, alloy materials, stainless steel, ceramics, polyoxymethylene or POM plastics, polytetrafluoroethylene or PTFE plastics, polypropylene or PP plastics, nylon or PA plastics, other plastics and other materials through the processing modes of numerical control lathes, CNC numerical control lathes, precision injection molding and the like. In fig. 1 to 6, the surface finish of the hole wall B of the hole K and the spherical force transmission element constituting the positioning structure should be made higher so as to reduce the friction force of the movable fit between the hole wall B of the hole K and the spherical force transmission element of the positioning structure and improve the sensitivity or precision of the force sensor; at the same time, attention should be paid to the improvement of the hole wall B of the hole K and the shape and size precision of the spherical force transmission element. The ceramic pressure sensitive component is not limited to a resistor type ceramic pressure sensitive membrane, or a ceramic pressure sensitive core with a concave circular middle part, or a columnar ceramic pressure sensitive core. The ceramic pressure sensitive component can also be a capacitive ceramic pressure sensitive membrane, a core body, a component and the like; it is contemplated that all pressure sensitive components that input a predetermined voltage or current, and that output an electrical signal or data that can vary with the pressure of the impact are pressure sensitive components of the present utility model. The shell, the cover, the bottom cover, the base body, the PCB and the like can be fixedly connected in a mortise-tenon structure, a buckle, gel, an adhesive, a screw and the like.

It is suggested by the above embodiment of the present utility model that the positioning hole K of the present utility model includes: round holes, tooth-shaped round holes, regular triangle holes, square holes, regular polygon holes and diamond holes; the regular triangle holes, square holes, regular polygon holes and diamond holes comprise acute angles, right angles, regular triangle holes with obtuse angles in arc transition or straight line transition, square holes, regular polygon holes, diamond holes and the like; it is also contemplated that the manner and configuration of positioning the spherical force transfer element is not limited to the illustrated aperture of the present utility model, and that any structure or component suitable for positioning the spherical force transfer element directly above the sensitive end of the ceramic pressure sensitive member in a movable fit with the spherical diameter of the spherical force transfer element, and for moving the spherical force transfer element a predetermined distance toward the ceramic pressure sensitive member in a movable fit is a positioning structure according to the present utility model. In addition, it is to be understood that the opening according to the present utility model is not limited to a circular opening, but may be a triangular, square, diamond-shaped opening, a triangular, square, diamond-shaped opening having an acute angle, a right angle, an obtuse angle with a circular arc transition or a straight line transition, or the like.

The foregoing has been provided merely by way of example of the utility model, and it is evident that various modifications, variations and combinations may be made thereto without departing from the broader aspects of the utility model, and therefore, the scope of the utility model is not limited to the specific examples and embodiments; this utility model is intended to cover all such modifications, variations or combinations of parts falling within the spirit and scope of the claimed utility model.

Claims (8)

1. A force sensor, comprising: pressure sensitive part, spherical force transmission element, casing, its characterized in that:

further comprises:

a support structure or support member provided at a lower portion of the housing, the support structure or support member being adapted to stabilize and support the pressure sensitive member,

a positioning structure having a predetermined depth or length disposed within the housing, the positioning structure being adapted to circumscribe the spherical force transmitting element directly above the sensitive end of the pressure sensitive member and being in a movable fit between the positioning structure and the spherical diameter portion of the spherical force transmitting element, the depth or length of the positioning structure being adapted to move the spherical diameter portion of the spherical force transmitting element a predetermined distance toward the pressure sensitive member in a movable fit,

an opening provided at an upper end of the housing, the spherical force transmitting element extending from the opening to a predetermined distance outside the housing, the opening being smaller than a spherical diameter of the spherical force transmitting member, and an edge of the opening being a predetermined distance from the spherical force transmitting element.

2. The force sensor of claim 1, wherein:

the positioning structure is a hole provided with a predetermined depth or length, in which hole the spherical force transmitting element is arranged.

3. The force sensor of claim 2, wherein:

the hole comprises: a round hole, a round hole with tooth-shaped edge and a regular polygon hole.

4. The force sensor of claim 1, wherein:

the pressure sensitive component includes: a circular ceramic pressure sensitive diaphragm, or a circular ceramic pressure sensitive core with a concave middle part, or a cylindrical ceramic pressure sensitive core, or one of silicon film pressure sensitive chips.

5. The force sensor of claim 1, wherein:

the housing includes: the shell and the cover of mutual fixed connection, the opening is circular opening, location structure set up on covering, be equipped with the ring shape brace table on the inner wall of shell, the ceramic pressure sensitive part has been arranged on the ring shape brace table.

6. The force sensor of claim 1, wherein:

the housing includes: the ceramic pressure-sensitive device comprises a shell and a circular supporting part which are fixedly connected with each other, wherein the opening is a circular opening, the circular opening and the positioning structure are arranged on the shell, and the circular supporting part is provided with a ceramic pressure-sensitive part.

7. The force sensor of claim 1, wherein:

the housing includes: the shell and the base body are fixedly connected with each other, the opening is a circular opening, the circular opening and the positioning structure are arranged on the shell, and the silicon film pressure sensitive chip is arranged on the base body.

8. The force sensor of claim 1, wherein:

the housing includes: the shell and the cover and the circular PCB circuit board of mutual fixed connection, the opening is circular opening, location structure set up on covering, be equipped with the ring shape brace table on the inner wall of shell, circular PCB circuit board sets up on the ring shape brace table, circular PCB circuit board is last to be arranged silicon film pressure sensitive chip.