Small annular force sensor

Abstract

The utility model discloses a miniature annular force sensor, which comprises an elastic body with a through hole in the center, a support plate and a strain gauge, the support plate is connected and arranged at the top of the elastic body with a gap, the strain gauge is fixedly arranged at the top of the elastic body, the support plate is provided with a pcb, and a bonding pad of the pcb is provided with a lead to be connected with the strain gauge. According to the utility model, the connecting column of the elastic body adopts the hollow column structure, and the inner wall and the outer wall of the connecting column are respectively provided with the annular first step surface and the annular second step surface, so that a stress surface can be effectively provided, force can be better sensed and transmitted, and the sensitivity and the measurement precision of the sensor to the force are improved; the inner wall of the supporting cylinder of the supporting plate is provided with the clamping convex block which is clamped between the supporting circular ring and the clamping circular ring, so that the supporting plate and the elastic body are connected conveniently, quickly and firmly through the clamping structure, and the sensor is convenient to assemble and maintain.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of force sensor, specifically relates to a small annular force sensor. BACKGROUND

[0002] Force sensor is a kind of device that converts the magnitude of force into related electrical signal, is widely used in power equipment, engineering machinery, industrial automation system and other fields.Its main function is to detect tension, tension, pressure, weight, torque, internal stress and strain and other mechanical quantities.

[0003] In the application of industrial robot joint torque detection, aero-engine annular flange connection pre-tightening force monitoring, minimally invasive surgical instrument annular holding force feedback, traditional solid structure sensor has the problems such as installation space conflict, multi-directional force coupling interference.The existing technology mostly adopts strain gauge array or fiber grating sensing principle, but there are limitations such as limited dynamic response, and large mass solid structure affects the high-frequency dynamic characteristics of sensor.

[0004] The Chinese patent with application number 202223570401.X provides an equal-strength beam high-precision force sensor, which includes a detection box and a sensor body arranged inside for acquiring pressure information, wherein the upper end of the sensor body is provided with a force receiving unit on the upper end of the detection box, the force receiving unit includes a sliding opening opened in the middle position of the upper end of the detection box, a piston column is slidably arranged at the position of the sliding opening, the upper end of the piston column is connected and fixed with the inner top of a piston sleeve, the lower end of the piston sleeve is slidably arranged outside the detection box, a sealing ring is arranged between the piston sleeve and the detection box.The technical scheme provided by the utility model can buffer the force, and when the pressure overload occurs, the sensor body can be set to be unloaded, thereby avoiding damage to the sensor body, but the space utilization is low, the solid structure needs to occupy a complete circular cross section, and the assembly requirement of annular components cannot be compatible, therefore, improvement is needed. UTILITY MODEL CONTENTS

[0005] The utility model aims at providing a small annular force sensor, and solves the technical problems of low space utilization of the force sensor in the prior art, solid structure needs to occupy a complete circular cross section, and cannot be compatible with the assembly requirement of annular components.

[0006] To achieve the above-mentioned purpose, the utility model provides the following technical scheme:

[0007] The utility model provides a small annular force sensor, which comprises an elastic body with a central through hole, a supporting plate and a strain gauge, the supporting plate is connected to the top of the elastic body with a gap, the strain gauge is fixedly arranged on the top of the elastic body, the supporting plate is provided with a pcb, and the solder pad of the pcb is connected with the strain gauge through a lead wire to form a sensor.

[0008] By adopting a hollow column structure for the connecting column of the elastic body, and arranging annular first and second step surfaces on the inner and outer walls respectively, a stress surface can be effectively provided, which helps to better perceive and transmit force, and improves the sensitivity and measurement accuracy of the sensor to force. By arranging a clamping protrusion on the inner wall of the support cylinder of the support plate, clamped between the support ring and the clamping ring, a clamping structure is achieved to facilitate the connection of the support plate and the elastic body, which is firm and convenient for the assembly and maintenance of the sensor.

[0009] Optionally, the elastic body comprises a shell and a connecting column, wherein the connecting column is preferably a hollow column structure, the top of which is fixedly connected to the shell, the inner wall of the connecting column is connected to an annular first step surface, and the outer wall of the connecting column is connected to an annular second step surface, to provide a stress surface. By arranging the connecting column as a hollow column structure, the overall weight of the sensor is reduced without significantly affecting the structural strength. The annular first and second step surfaces provide a larger and more regular stress area, so that force can be more evenly distributed on the elastic body. When subjected to external force, the elastic body can more accurately convert force into strain, and the strain gauge can more accurately capture these changes, thereby improving the perception accuracy of the sensor to force and enabling more accurate measurement of small force changes. The hollow column structure is fixedly connected to the shell, forming a stable frame structure. This structure helps to disperse the force and avoid stress concentration in a certain point or area, thereby improving the overall structural strength of the elastic body.

[0010] Optionally, the elastic body further comprises a fixed ring, a support ring and a clamping ring, which are sequentially fixedly sleeved on the outer wall of the shell from bottom to top. The support ring and the connecting portion of the support plate abut to support. By sleeving the three rings on the outer wall of the shell, a clear positioning reference is provided for each component. During installation, other components (such as the support plate) can be accurately installed according to the positions of these rings, ensuring the accurate relative positions between each component and improving the assembly accuracy and efficiency.

[0011] Optionally, the support plate is fixedly provided with a hollow structure support cylinder, which has the same outer diameter as the support plate. A clamping protrusion is fixedly arranged on the inner wall of the support cylinder near the end portion, and is clamped between the support ring and the clamping ring. By clamping the clamping protrusion between the two rings, the precise butt joint of the support plate and the elastic body can be quickly achieved during assembly, reducing installation errors and ensuring the coaxiality and stability of the overall structure of the sensor, thereby improving the measurement accuracy of the sensor to force.

[0012] Optionally, the support plate is provided with a circular hole, the circular hole is matched with the hole diameter of the elastic body through hole, and the support plate is further provided with a slot matched with the number of strain gauges, by providing the circular hole on the support plate, the connecting piece (such as a bolt, a pin and the like) is convenient to pass through the circular hole and the elastic body through hole, reliable connection of the support plate and the elastic body is realized, the hollow annular topological structure is adopted, the lightweight and integrated design is realized while the radial rigidity is maintained, the annular mounting space can be embedded, and the force measurement demand of special scenes such as mechanical joints and pipeline connecting pieces can be applied.

[0013] Optionally, the annular groove of the clamping part is formed between the inside of the shell and the connecting column, and the required stress generated by the deformation of the sensor is ensured by arranging the annular groove.

[0014] Compared with the prior art, the utility model has the following beneficial effects:

[0015] 1, the small annular force sensor of the utility model through the connecting column of the elastic body adopts the hollow column structure, and the inner wall and the outer wall are provided with annular first step surface and second step surface respectively, can effectively provide the stress surface, help better perception and transmission force, improve the sensitivity and measurement accuracy of the sensor to force, through setting the clamping lug in the support cylinder inner wall of the support plate, clamp between the support ring and the clamping ring, realize the clamping structure and make the connection of the support plate and the elastic body convenient and fast, and the connection is firm, convenient for the assembly and maintenance of the sensor.

[0016] 2, the small annular force sensor of the utility model through the clamping lug clamped between the two rings, in the assembly process, the accurate butt joint of the support plate and the elastic body can be realized quickly, the installation error is reduced, the coaxiality and stability of the overall structure of the sensor are guaranteed, and then the measurement accuracy of the sensor to force is improved, and the required stress generated by the deformation of the sensor is ensured by arranging the annular groove. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a structural schematic view of the utility model;

[0018] Figure 2 It is an elastic body structure schematic view of the utility model;

[0019] Figure 3 It is an elastic body half cut structure schematic view of the utility model;

[0020] Figure 4 It is a support plate and support cylinder connection structure schematic view of the utility model;

[0021] Figure 5 It is an elastic body and support plate assembly half cut structure schematic view of the utility model.

[0022] In the figure: 1-elastic body, 11-shell, 12-connecting column, 13-first step surface, 14-second step surface, 15-fixing ring, 16-supporting ring, 17-clamping ring, 18-first annular groove, 19-second annular groove, 2-support plate, 21-support cylinder, 22-clamping protrusion, 23-groove, 24-circular hole, 3-strain gauge. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0024] One embodiment, such as Figures 1 to 5 As shown, a small ring force sensor is provided, including an elastic body 1, a support plate 2, and a strain gauge 3. The elastic body 1 has a through hole in its center that extends longitudinally through the elastic body 1. The support plate 2 is connected to the top of the elastic body 1 with a gap. The strain gauge 3 is fixedly mounted on the top of the elastic body 1. In this embodiment, a PCB is welded to the bottom of the support plate 2. The pads of the PCB are connected to the pads of the strain gauge 3 by welding to form the sensor.

[0025] In this embodiment, the strain gauge 3 is preferably a direct application of the existing technology based on conductive carbon fiber strain gauges. The strain gauge 3 is attached to the elastomer 1, which has been sandblasted on top. In this embodiment, the strain gauge 3 is connected to the PCB pads to form a Wheatstone bridge as in the prior art, forming a force sensor module. It adopts a hollow ring topology structure, which achieves lightweight and integrated design while maintaining radial stiffness. It can be embedded in the ring installation space and is suitable for force measurement needs in special scenarios such as mechanical joints and pipe connectors.

[0026] It should be noted that in this embodiment, the PCB is preferably a direct application of existing products, such as FR-4 material PCB, multilayer PCB, flexible PCB (FPC), or rigid-flex PCB in the prior art, so as to realize the accurate and stable transmission of the electrical signal corresponding to the resistance change of the strain gauge 3 due to the force through the connection with the strain gauge 3 by the wire.

[0027] refer to Figure 2 and Figure 3 As shown, in this embodiment, the elastomer 1 includes a shell 11 and a connecting post 12. The shell 11 and the connecting post 12 are preferably cast using an integrated molding technology in the prior art. In this embodiment, the connecting post 12 is preferably a hollow post structure, and the space between the connecting post 12 and the inner wall of the shell 11 is hollow to form an annular groove structure.

[0028] refer to Figure 3As shown, the inner wall of the connecting column 12 in this embodiment is fixed with a first step surface 13, wherein the first step surface 13 is preferably formed by respectively opening two holes towards the two ends of the connecting column 12, and the two holes are formed due to the diameter difference. In this embodiment, the outer wall of the end of the connecting column 12 away from the support plate 2 is further provided with a second step surface 14, which is preferably formed by opening a ring-shaped groove towards the outer wall of the connecting column 12 in this embodiment.

[0029] The ring-shaped groove inside the elastic body 1 in this embodiment includes a first ring-shaped groove 18 and a second ring-shaped groove 19, wherein the second ring-shaped groove 19 and the first ring-shaped groove 18 are sequentially opened upwards along the bottom of the elastic body 1 from bottom to top. In this embodiment, the second ring-shaped groove 19 is preferably a tapering groove from bottom to top, and the bottom of the second ring-shaped groove 18 is preferably a rounded structure.

[0030] In use, when installing some components that need to be closely matched with the inner wall of the connecting column 12, the first step surface 13 can limit the axial position of the components to ensure their installation in place, improve the precision and consistency of assembly, and thus improve the performance stability of the entire sensor. The second step surface 14 formed by opening a ring-shaped groove towards the outer wall of the end of the connecting column 12 can be connected with the corresponding structure on other components for easy installation and disassembly.

[0031] Reference Figure 4 and Figure 5 As shown, the support plate 2 in this embodiment includes a support cylinder 21 with the same diameter as the support plate 2, wherein the support cylinder 21 is preferably hollow and made by integrated molding technology in the prior art. The inner wall of the end of the support cylinder 21 is welded with a pair of clamping protrusions 22, wherein the clamping protrusions 22 are clamped to the outer wall of the elastic body 1. In this embodiment, the top of the support plate 2 is provided with a slot 23 and a circular hole 24, wherein the circular hole 24 is preferably adapted to the diameter of the through hole 24 of the connecting column 12, and the slot 23 in this embodiment is adapted to the number of strain gauges 3 on the top of the elastic body 1, and the strain gauges 3 are installed and fixed in the projection direction of the slot 23.

[0032] Reference Figure 4 and Figure 5 As shown, the elastic body 1 in this embodiment further includes a fixed ring 15, a support ring 16 and a clamping ring 17, wherein the fixed ring 15, the support ring 16 and the clamping ring 17 are sequentially fixed to the outer wall of the shell 11 upwards, and the outer diameters of the fixed ring 15, the support ring 16 and the clamping ring 17 are sequentially reduced. In this embodiment, the clamping protrusions 22 are clamped between the support ring 16 and the clamping ring 17 when installed, and the end of the clamping protrusions 22 abuts against the support ring 16.

[0033] In use, when installing some components which need to be closely matched with the inner wall of the connecting column 12, the outer wall or the inner wall of the connecting column 12 is connected with the components, the bottom of the second annular groove 19 is provided with a round corner structure, the required stress generated when the sensor is deformed is ensured, the first annular groove 18 is upwardly formed at the bottom of the elastic body 1, so that the force is dispersed around the annular groove area in the transmission process, the force is avoided to be concentrated in a local area of the elastic body 1, so that the elastic body 1 is more uniformly stressed, the overall sensing accuracy of the sensor to the force is improved, and the second annular groove 19 can be used as a positioning structure in the assembly process of the sensor and accurately matched with other components.

[0034] The embodiments of the utility model are described above in combination with the drawings, but the utility model is not limited to the above-mentioned specific implementation, the above-mentioned specific implementation is only illustrative, and is not restrictive, and the person skilled in the art can make a lot of forms under the inspiration of the utility model without departing from the scope of the utility model and the protection scope of the claims, and these all belong to the protection of the utility model.

Claims

1. A small annular force sensor characterized by: The elastic body (1) includes a center band hole, a support plate (2) and a strain gauge (3), the support plate (2) is connected to the top of the elastic body (1) with a gap, the strain gauge (3) is fixed to the top of the elastic body (1), the support plate (2) is provided with a pcb, the pads of the pcb are connected with the strain gauge (3) through wires, and the sensor is formed.

2. A small ring force sensor according to claim 1, characterized in that The elastic body (1) includes a shell (11) and a connecting column (12), wherein the connecting column (12) is preferably a hollow column structure, the top of the connecting column (12) is fixedly connected with the shell (11), the inner wall of the connecting column (12) is connected with a first step surface (13) in an annular structure, and the outer wall of the connecting column (12) is connected with a second step surface (14) in an annular structure, so as to provide a stress surface.

3. A small ring force sensor according to claim 2, wherein: The elastic body (1) further includes a fixed ring (15), a supporting ring (16) and a clamping ring (17), the fixed ring (15), the supporting ring (16) and the clamping ring (17) are sequentially fixedly sleeved on the outer wall of the shell (11) from bottom to top, and the connecting part of the supporting ring (16) and the support plate (2) abuts and supports.

4. A small ring force sensor according to claim 3, characterized in that: The support plate (2) is fixedly provided with a hollow support cylinder (21), the support cylinder (21) has the same outer diameter as the support plate (2), the inner wall of the end portion of the support cylinder (21) is fixedly provided with a clamping protrusion (22), and the clamping protrusion (22) is clamped between the supporting ring (16) and the clamping ring (17).

5. A small ring force sensor according to claim 4, characterized in that: The support plate (2) is provided with a circular hole (24), the circular hole (24) is matched with the hole diameter of the through hole of the elastic body (1), and the support plate (2) is further provided with a notch (23) matched with the number of strain gauges (3).

6. A small ring force sensor according to claim 5, wherein: The inside of the shell (11) and the connecting column (12) form an annular groove of the clamping part.

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