Force sensor

Abstract

This invention relates to the field of robotics and provides a force sensor comprising a cylindrical outer shell open at both ends, a first cover plate and a second cover plate, an elastic body, and strain gauges fixed to the elastic body. The elastic body includes an annular elastic anchor fixed to the outer shell, a central platform spaced apart inside the elastic anchor, three crossbeams extending from the central platform toward the outer shell and connected to the elastic anchor, and evenly spaced along the circumference of the central platform; and three vertical beams extending from the central platform toward the first cover plate and connected to the elastic anchor, and evenly spaced along the circumference of the central platform. The strain gauges include a first strain gauge fixed to each crossbeam and a second strain gauge fixed to each vertical beam; each crossbeam and each vertical beam are perpendicular to each other. Compared with related technologies, the force sensor of this invention has lower manufacturing difficulty, smaller size, better decoupling effect, and facilitates improvement of sensor accuracy and precision.

Description

Technical Field

[0001] This invention relates to the field of robotics, and more particularly to a force sensor. Background Technology

[0002] Currently, six-dimensional force sensors can simultaneously measure the three-dimensional orthogonal force components (Fx / Fy / Fz) and the three-dimensional orthogonal torque components (Mx / My / Mz) at a point in space. These sensors are used to detect the forces and torques experienced by a robot's end effector when it contacts or grasps an object, providing force-sensing information for the robot's force and compliant control, thus enabling it to perform complex and delicate tasks. As robots develop towards lighter weight, smaller size, and more precise operation, there is a need to design sensors that are smaller, lighter, and more sensitive.

[0003] Among related technologies, the most common structures are the three-strain beam structure and the cross-beam structure. The three-strain beam structure includes a fixed ring, a central platform spaced apart within the fixed ring, three main beams connecting the fixed ring to the central platform, three floating beams, and twelve strain gauges installed along the length of the three main beams. The cross-beam structure includes a fixed ring, a central platform spaced apart within the fixed ring, four main beams connecting the fixed ring to the central platform, four floating beams, and twenty-four strain gauges installed along the length of the four main beams.

[0004] Furthermore, since only one strain gauge needs to be placed along the length of the main beam in a three-strain beam structure, it is easier to miniaturize than a cross-beam structure. However, when the structure is reduced to a certain size, such as when the sensor diameter is less than or equal to 20mm, as the length of the main beam decreases, and because strain gauges need to be placed on the upper and lower surfaces and both sides of the main beam in a three-strain beam structure, the size of the strain gauges simultaneously limits the height and width of the main beam. This results in very small deformation of the main beam when the sensor detects force and torque, reducing the strain that can be sensed by the strain gauges and decreasing the sensor sensitivity. In addition, the reduction in sensor size reduces the internal space of the sensor, resulting in less operating space for strain gauge placement, making the strain gauge placement process more difficult.

[0005] Therefore, it is necessary to provide a new force sensor to solve the above-mentioned technical problems. Summary of the Invention

[0006] The purpose of this invention is to provide a force sensor that is easy to manufacture, small in size, has good decoupling effect, and facilitates the improvement of the accuracy and precision of the sensor.

[0007] To achieve the above objectives, embodiments of the present invention provide a force sensor, comprising a cylindrical outer shell having a receiving space and openings at both ends, a first cover plate and a second cover plate respectively covering the openings at both ends of the outer shell, an elastic body housed within the receiving space, and strain gauges fixed to the elastic body. The elastic body includes an annular elastic anchor fixed to the outer shell, a central platform spaced apart on the inner side of the elastic anchor, three crossbeams extending from the central platform toward the outer shell and connected to the elastic anchor and equally spaced along the circumference of the central platform, and three vertical beams extending from the central platform toward the first cover plate and connected to the elastic anchor and equally spaced along the circumference of the central platform. The strain gauges include a first strain gauge fixed to each of the crossbeams and a second strain gauge fixed to each of the vertical beams; each crossbeam and each vertical beam are arranged perpendicular to each other.

[0008] Preferably, the extensions of two adjacent crossbeams along their length direction form a 120° angle; the projection of each vertical beam along its length direction lies between two adjacent crossbeams and overlaps with the angle bisector of the angle between two adjacent crossbeams.

[0009] Preferably, the second cover plate is spaced apart from the outer shell, the surface of the center platform facing the second cover plate is fixed to the second cover plate, the crossbeam is spaced apart from the second cover plate, the crossbeam has a rectangular cross-section perpendicular to its extension direction, the crossbeam includes a first mounting surface facing the first cover plate, a second mounting surface facing the second cover plate, and a side surface connecting the first mounting surface and the second mounting surface, each crossbeam is provided with two first strain gauges, and the two first strain gauges on each crossbeam are respectively mounted on the first mounting surface and the second mounting surface; each vertical beam is provided with two second strain gauges; the two second strain gauges on the same vertical beam are parallel to the side surface.

[0010] Preferably, the crossbeam includes a first main beam fixed to the central platform and a first floating beam extending from the end of the first main beam away from the central platform, the thickness of the first main beam being greater than the thickness of the first floating beam; the end of the first floating beam away from the first main beam is connected to the elastic anchor; the first mounting surface, the second mounting surface, and the side surface are disposed on the first main beam, and the first strain gauge is fitted and fixed to the first main beam.

[0011] Preferably, the vertical beam includes a second main beam fixed to the central platform and a second floating beam extending from the end of the second main beam away from the central platform toward the first cover plate, wherein the thickness of the second main beam is greater than the thickness of the second floating beam; the end of the second floating beam away from the second main beam is fixed to the elastic anchor.

[0012] The second main beam has a rectangular cross-section along its extension direction. The second main beam includes a third mounting surface and a fourth mounting surface parallel to the side surface. Two second strain gauges on the same vertical beam are respectively disposed on the third mounting surface and the fourth mounting surface.

[0013] Preferably, the elastic anchor includes a first fixing ring and a second fixing ring that are spaced apart from each other;

[0014] The outer casing includes an inner wall facing the elastic anchor, the outer peripheral side of the first fixing ring is attached to the inner wall, and one end of each second floating beam away from the second main beam is fixed to the first fixing ring; the surface of the first fixing ring facing the first cover plate is fixed to the first cover plate.

[0015] The outer periphery of the second fixing ring is fixed to the inner wall, and the end of each of the first floating beams away from the first main beam is respectively fixed to the second fixing ring.

[0016] Preferably, the first fixing ring includes a first fixing ring body and three equally spaced fixing parts extending inward from the inner circumference of the first fixing ring body; the three fixing parts are connected to the three second floating beams in a one-to-one correspondence.

[0017] Preferably, the second fixing ring is spaced apart from the second cover plate, and the second fixing ring is fixedly connected to the outer shell by bolts.

[0018] Preferably, the central platform includes a hexagonal central platform body, a positioning hole formed by recessing the central platform body from the center position on the side near the second cover plate toward the direction away from the second cover plate, and a plurality of fixing holes formed by recessing the central platform body from the side near the second cover plate toward the direction away from the second cover plate; the plurality of fixing holes are evenly spaced on the outer periphery of the positioning hole.

[0019] The second cover plate includes a second cover plate body, a boss protruding from the second cover plate body towards the side near the first cover plate, a positioning post protruding from the boss towards the side near the first cover plate, and a plurality of mounting holes formed through the second cover plate body and evenly distributed among each other; the boss is disposed on the side of the central platform body near the second cover plate, and the positioning post is disposed in the positioning hole; the plurality of mounting holes and the plurality of fixing holes are arranged opposite to each other, and are fixedly connected by a plurality of bolts passing through the plurality of mounting holes and the plurality of fixing holes in sequence.

[0020] Preferably, the central platform further includes three connecting portions formed by the central platform body extending towards one side of the outer shell; one end of the three vertical beams near the second cover plate is fixed to the three connecting portions; wherein the three connecting portions and the three horizontal beams are respectively located on the six outer sides of the central platform body.

[0021] Preferably, the distance between the first strain gauge and the second strain gauge and the central stage is 0.5~1mm.

[0022] Preferably, the gap between the second cover plate and the second fixing ring along their axial direction is 1~2mm.

[0023] Preferably, the elastomer is made of any one of aluminum alloy, magnesium alloy, titanium alloy, stainless steel, and PEEK polymer; the first cover plate, the outer shell, and the second cover plate are all made of any one of aluminum alloy, magnesium alloy, titanium alloy, and stainless steel.

[0024] Compared with related technologies, the force sensor of the present invention, by respectively setting a first cover plate and a second cover plate at opposite ends of the outer shell, elastically setting an elastic body on the inner circumference of the outer shell, and providing strain gauges on the elastic body; the elastic body includes an elastic anchor fixed to the outer shell and in an annular shape, a central platform spaced apart inside the elastic anchor, three crossbeams extending from the central platform toward the outer shell and connected to the elastic anchor and equally spaced along the circumference of the central platform, and three vertical beams extending from the central platform toward the first cover plate and connected to the elastic anchor and equally spaced along the circumference of the central platform. The device includes a first strain gauge fixed to each crossbeam and a second strain gauge fixed to each vertical beam; each crossbeam and each vertical beam are arranged perpendicular to each other; by adjusting the length of the crossbeam and the height of the vertical beam, the strain response of the first and second strain gauges can be adjusted respectively, improving the patching accuracy, thereby improving the accuracy and precision of the sensor; by using the force sensor form of the crossbeam and vertical beam, the patching process of the strain gauges on the upper and lower surfaces of the crossbeam and the strain gauges on the side of the vertical beam is decoupled, which is beneficial for miniaturizing the sensor patching process and reducing the difficulty of the patching process. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0026] Figure 1 This is a three-dimensional structural diagram of the force sensor provided in an embodiment of the present invention;

[0027] Figure 2 An exploded view of the force sensor provided in an embodiment of the present invention;

[0028] Figure 3 for Figure 1 AA-line sectional view;

[0029] Figure 4 This is a schematic diagram of the structure of the elastic body of the force sensor provided in an embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of the structure of the second cover plate of the force sensor provided in an embodiment of the present invention;

[0031] Figure 6 This is a schematic diagram of the structure of the first main beam of the force sensor provided in an embodiment of the present invention;

[0032] Figure 7 for Figure 1 BB line section view.

[0033] In the diagram, 100 is the force sensor, 1 is the first cover plate, 2 is the outer shell, 20 is the receiving space, 21 is the inner wall, 3 is the second cover plate, 31 is the second cover plate body, 32 is the boss, 33 is the positioning post, 34 is the mounting hole, 4 is the elastomer, 41 is the center platform, 411 is the center platform body, 412 is the positioning hole, 413 is the fixing hole, 414 is the connecting part, 42 is the crossbeam, 421 is the first main beam, 4211 is the first mounting surface, 421 2. Second mounting surface; 4213. Side surface; 422. First floating beam; 43. Strain gauge; 431. First strain gauge; 432. Second strain gauge; 44. Vertical beam; 441. Second main beam; 4411. Third mounting surface; 4412. Fourth mounting surface; 442. Second floating beam; 45. Elastic anchor; 451. First fixing ring; 4511. First fixing ring body; 4512. Fixing part; 452. Second fixing ring. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Please see Figures 1-6As shown, this embodiment of the invention provides a force sensor 100, which includes a cylindrical outer shell 2 with a receiving space 20 and openings at both ends, a first cover plate 1 and a second cover plate 3 respectively covering the openings at both ends of the outer shell 2, an elastic body 4 housed within the receiving space 20, and strain gauges 43 fixed to the elastic body 4. The opposite ends of the elastic body 4 are respectively fixed to the first cover plate 1 and the second cover plate 3. By mounting the outer shell 2 on the first cover plate 1, fixing one end of the elastic body 4 to the first cover plate 1, and fixing the other end of the elastic body 4 to the second cover plate 3, elastic support is achieved using the elastic body 4, and a certain degree of sensor decoupling can be achieved through the elastic body 4.

[0036] The elastic body 4 includes an annular elastic anchor 45 fixed to the outer shell 2, a central platform 41 spaced apart inside the elastic anchor 45, three crossbeams 42 extending from the central platform 41 toward the outer shell 2 and connected to the elastic anchor 45 and evenly spaced along the circumference of the central platform 41, and three vertical beams 44 extending from the central platform 41 toward the first cover plate 1 and connected to the elastic anchor 45 and evenly spaced along the circumference of the central platform 41. The strain gauge 43 includes a first strain gauge 431 fixed to each of the crossbeams 42 and a second strain gauge 432 fixed to each of the vertical beams 44. Each crossbeam 42 and each vertical beam 44 are perpendicular to each other.

[0037] Specifically, by adjusting the length of the crossbeam 42 and the height of the vertical beam 44, the strain response of the first strain gauge 431 and the second strain gauge 432 are adjusted respectively, improving the patching accuracy and thus enhancing the sensor's precision and accuracy. By using the force sensor 100 form of the crossbeam 42 and the vertical beam 44, the patching process of the strain gauges on the upper and lower surfaces of the crossbeam 42 and the strain gauges on the sides of the vertical beam 44 is decoupled, facilitating the miniaturization of the sensor patching process and reducing its complexity. The crossbeam 42 is horizontally placed and extends horizontally, with the first strain gauge 431 located on its upper or lower length. The vertical beam 44 is vertically placed and extends vertically, with the second strain gauge 432 located on its left or right length.

[0038] like Figure 7As shown, the extensions of two adjacent crossbeams 42 along their length directions form a 120° angle; the projection of each vertical beam 44 along its length direction lies between two adjacent crossbeams 42, and the angle bisectors of the angles between two adjacent crossbeams 42 overlap. Specifically, each vertical beam 44 and its adjacent crossbeam 42 are distributed at 60° intervals in a plane parallel to the central platform 41. Within a 360° plane, three crossbeams 42 can achieve three-dimensional force sensing detection, and three vertical beams 44 can also achieve three-dimensional force sensing detection. Thus, by uniformly distributing the three crossbeams 42 at 120° angles and the three vertical beams 44 at 120° angles, with each vertical beam 44 at a 60° angle to its adjacent crossbeam 42, six-dimensional force sensing detection can be achieved.

[0039] The second cover plate 3 is spaced apart from the outer shell 2. The surface of the center platform 41 facing the second cover plate 3 is fixed to the second cover plate 3. The crossbeam 42 is spaced apart from the second cover plate 3. The crossbeam 42 has a rectangular cross section perpendicular to its extension direction. The crossbeam 42 includes a first mounting surface 4211 facing the first cover plate 1, a second mounting surface 4212 facing the second cover plate 3, and a side surface 4213 connecting the first mounting surface 4211 and the second mounting surface 4212. Each crossbeam 42 is provided with two first strain gauges 431. The two first strain gauges 431 on each crossbeam 42 are respectively mounted on the first mounting surface 4211 and the second mounting surface 4212. Each vertical beam 44 is provided with two second strain gauges 432. The two second strain gauges 432 on the same vertical beam 44 are parallel to the side surface 4213.

[0040] The crossbeam 42 includes a first main beam 421 fixed to the central platform 41 and a first floating beam 422 extending from the end of the first main beam 421 away from the central platform 41. The thickness of the first main beam 421 is greater than the thickness of the first floating beam 422. The end of the first floating beam 422 away from the first main beam 421 is connected to the elastic anchor 45. The first mounting surface 4211, the second mounting surface 4212, and the side surface 4213 are disposed on the first main beam 421. The first strain gauge 431 is attached and fixed to the first main beam 421.

[0041] The vertical beam 44 includes a rectangular second main beam 441 fixed to the central platform 41 and a second floating beam 442 extending from the end of the second main beam 441 away from the central platform 41 toward the first cover plate 1. The thickness of the second main beam 441 is greater than the thickness of the second floating beam 442. The end of the second floating beam 442 away from the second main beam 441 is fixed to the elastic anchor 45.

[0042] The second main beam 441 has a rectangular cross-section along its extension direction. The second main beam 441 includes a third mounting surface 4411 and a fourth mounting surface 4412 parallel to the side surface 4213. Two second strain gauges 432 on the same vertical beam 44 are respectively disposed on the third mounting surface 4411 and the fourth mounting surface 4412.

[0043] Specifically, the first mounting surface 4211 and the second mounting surface 4212 are located on the upper and lower surfaces of the crossbeam 42, and the third mounting surface 4411 and the fourth mounting surface 4412 are located on the left and right surfaces of the vertical beam 44. By attaching the first strain gauge 431 to the upper and lower surfaces of the first main beam 421 of the three crossbeams 42 respectively, the strain response of the strain gauges on the three crossbeams 42 can be adjusted and optimized by adjusting the length of the three crossbeams 42 and the height of the first main beam 421 and the first floating beam 422. Similarly, by attaching the second strain gauge 432 to the third mounting surface 4411 and the fourth mounting surface 4412 (surfaces parallel to the sides of the crossbeams 42) of the three vertical beams 44, the strain response of the second strain gauge 432 on the three vertical beams 44 can be adjusted and optimized by adjusting the height of the three vertical beams 44 and the width (perpendicular to the crossbeams 42) of the second main beam 441 and the second floating beam 442. When the sensor detects forces Fx (force along the X-axis), Fy (force along the Y-axis), and Mz (torque about the Z-axis), the response is measured via three vertical beams 44. When the sensor detects forces Fz (force along the Z-axis), Mx (torque about the X-axis), and My (torque about the Y-axis), the response is measured via three horizontal beams 42. Through the design of the horizontal beams 42 and vertical beams 44, a certain degree of decoupling of the sensor strain response can be achieved.

[0044] Optionally, the strain gauge 43 comprises 12 strain gauges. One first strain gauge 431 is attached to each of the six surfaces (upper and lower) of the first main beam 421 of the three crossbeams 42, for a total of six first strain gauges 431. One second strain gauge 432 is attached to each of the six surfaces (left and right) of the three vertical beams 44, for a total of six second strain gauges 432. The strain gauge direction of the first strain gauge 431 is along the length of the first main beam 421. Furthermore, by using the force sensor 100 form of the crossbeams 42 and vertical beams 44, the mounting process of the first strain gauge 431 and the second strain gauge 432 is decoupled, which facilitates the miniaturization of the sensor mounting process, reduces the difficulty of the mounting process, and improves the mounting accuracy, thereby improving the accuracy and precision of the sensor. By attaching the strain gauge to the surface of the object being measured, the strain of the object's surface can be converted into a change in resistance, and the strain of the object can be calculated by measuring the change in resistance.

[0045] The elastic anchor 45 includes a first fixing ring 451 and a second fixing ring 452 spaced apart from each other. The outer shell 2 includes an inner wall 21 facing the elastic anchor 45. The outer periphery of the first fixing ring 451 is attached to the inner wall. One end of each second floating beam 442 away from the second main beam 441 is fixed to the first fixing ring 451. The surface of the first fixing ring 451 facing the first cover plate 1 is fixed to the first cover plate 1. The outer periphery of the second fixing ring 452 is fixed to the inner wall of the outer shell 2. One end of each first floating beam 422 away from the first main beam 421 is fixed to the inner periphery of the second fixing ring 452. The first fixing ring 451 and the second fixing ring 452 can respectively support the horizontal beam 42 and the vertical beam 44. The first strain gauge 431 and the second strain gauge 432 sense the minute deformation of the object to realize the indirect measurement of physical quantities such as force, stress, strain and displacement, thereby improving the accuracy and precision of the sensor.

[0046] The first fixing ring 451 includes a first fixing ring body 4511 and three equally spaced fixing parts 4512 extending inward from the inner circumference of the first fixing ring body 4511; the three fixing parts 4512 are connected one-to-one with the three second floating beams 442. By fixing the three vertical beams 44 with the three fixing parts 4512 respectively, the vertical beams 44 can be prevented from deforming and hitting the inner wall of the outer casing 2, thus ensuring good detection accuracy of the vertical beams 44. At the same time, the fixing parts 4512 also provide support and fixation for the vertical beams 44, improving the support strength of the vertical beams 44.

[0047] The second fixing ring 452 is spaced apart from the second cover plate 3. The second fixing ring 452 is fixedly connected to the outer shell 2 by bolts, and the first fixing ring 451 is fixedly connected to the first cover plate 1 by bolts. The bolt connection facilitates the removal and installation of the first fixing ring 451 and the second fixing ring 452 from the first cover plate 1 and the outer shell 2, respectively. Optionally, three bolts are used.

[0048] The central platform 41 includes a hexagonal central platform body 411, a positioning hole 412 formed by recessing the central platform body 411 from the center position on the side near the second cover plate 3 toward the side away from the second cover plate 3, and a plurality of fixing holes 413 formed by recessing the central platform body 411 from the side near the second cover plate 3 toward the side away from the second cover plate 3; the plurality of fixing holes 413 are evenly spaced on the outer periphery of the positioning hole 412. The second cover plate 3 includes a second cover plate body 31, a boss 32 protruding from the second cover plate body 31 towards the side near the first cover plate 1, a positioning post 33 protruding from the boss 32 towards the side near the first cover plate 1, and a plurality of mounting holes 34 formed through the second cover plate body 31 and evenly distributed among each other; the boss 32 covers the side of the central platform body 411 near the second cover plate 3, and the positioning post 33 is disposed in the positioning hole 412; the plurality of mounting holes 34 and the plurality of fixing holes 413 are arranged opposite to each other, and are fixedly connected by a plurality of bolts passing through the plurality of mounting holes 34 and the plurality of fixing holes 413 in sequence. The central platform body 411 is used to install the crossbeam 42 and the vertical beam 44 respectively. The central platform body 411 and the second cover plate 3 are positioned by the positioning holes 412 and the positioning post 33, and fixedly connected by a plurality of bolts passing through the plurality of mounting holes 34 and the plurality of fixing holes 413 in sequence, so that the central platform 41 and the second cover plate 3 can be fixedly connected.

[0049] The central platform 41 also includes three connecting portions 414 formed by the central platform body 411 extending towards one side of the outer shell 2; one end of the three vertical beams 44 near the second cover plate 3 is fixed to the three connecting portions 414; wherein the three connecting portions 414 and the three horizontal beams 42 are respectively located on the six outer sides of the central platform body 411.

[0050] The distances between the first strain gauge 431 and the second strain gauge 432 and the central stage 41 are both 0.5~1mm.

[0051] The axial gap between the second cover plate 3 and the second fixing ring 452 is 1~2mm. This prevents the second cover plate 3 from contacting the outer shell 2 when strain occurs, thus improving the accuracy and precision of the sensor.

[0052] The elastomer 4 is made of any one of the following materials: aluminum alloy, magnesium alloy, titanium alloy, stainless steel, and the polymer material PEEK (polyether ether ketone). The elastomer 4 has high structural strength and good elastic properties. The elastomer 4 can also be a non-metallic material, as long as it can undergo elastic deformation in its recovery state.

[0053] The first cover plate 1, the outer shell 2, and the second cover plate 3 are all made of any one of the following materials: aluminum alloy, magnesium alloy, titanium alloy, and stainless steel. This ensures that the first cover plate 1, the outer shell 2, and the second cover plate 3 have high structural strength, are easy to manufacture, and save costs.

[0054] Compared with related technologies, the force sensor of the present invention, by respectively setting a first cover plate and a second cover plate at opposite ends of the outer shell, elastically setting an elastic body on the inner circumference of the outer shell, and providing strain gauges on the elastic body; the elastic body includes an elastic anchor fixed to the outer shell and in an annular shape, a central platform spaced apart inside the elastic anchor, three crossbeams extending from the central platform toward the outer shell and connected to the elastic anchor and equally spaced along the circumference of the central platform, and three vertical beams extending from the central platform toward the first cover plate and connected to the elastic anchor and equally spaced along the circumference of the central platform. The device includes a first strain gauge fixed to each crossbeam and a second strain gauge fixed to each vertical beam; each crossbeam and each vertical beam are arranged perpendicular to each other; by adjusting the length of the crossbeam and the height of the vertical beam, the strain response of the first and second strain gauges can be adjusted respectively, improving the patching accuracy, thereby improving the accuracy and precision of the sensor; by using the force sensor form of the crossbeam and vertical beam, the patching process of the strain gauges on the upper and lower surfaces of the crossbeam and the strain gauges on the side of the vertical beam is decoupled, which is beneficial for miniaturizing the sensor patching process and reducing the difficulty of the patching process.

[0055] The above description is merely an embodiment of the present invention. It should be noted that those skilled in the art can make improvements without departing from the inventive concept of the present invention, but these improvements all fall within the protection scope of the present invention.

Claims

1. A force sensor, comprising a cylindrical outer shell having a receiving space and openings at both ends, a first cover plate and a second cover plate respectively covering the openings at both ends of the outer shell, an elastic body received within the receiving space, and a strain gauge fixed to the elastic body, characterized in that, The elastomer includes an annular elastic anchor fixed to the outer shell, a central platform spaced apart inside the elastic anchor, three crossbeams extending from the central platform toward the outer shell and connected to the elastic anchor and evenly spaced along the circumference of the central platform, and three vertical beams extending from the central platform toward the first cover plate and connected to the elastic anchor and evenly spaced along the circumference of the central platform. The strain gauges include a first strain gauge fixed to each of the crossbeams and a second strain gauge fixed to each of the vertical beams; the first strain gauge and the second strain gauge respectively sense the deformation of the crossbeams and vertical beams to generate resistance changes; each crossbeam and each vertical beam are arranged perpendicular to each other. The projection of each vertical beam along its length direction lies between two adjacent horizontal beams and overlaps with the angle bisector of the angle between two adjacent horizontal beams; The second cover plate is spaced apart from the outer shell. The surface of the central platform facing the second cover plate is fixed to the second cover plate. The crossbeam is spaced apart from the second cover plate. The crossbeam has a rectangular cross-section perpendicular to its extension direction. The crossbeam includes a first mounting surface facing the first cover plate, a second mounting surface facing the second cover plate, and a side surface connecting the first mounting surface and the second mounting surface. Each crossbeam is provided with two first strain gauges, which are respectively mounted on the first mounting surface and the second mounting surface. Each vertical beam is provided with two second strain gauges. The two second strain gauges on the same vertical beam are parallel to the side surface. The crossbeam includes a first main beam fixed to the central platform and a first floating beam extending from the end of the first main beam away from the central platform. The thickness of the first main beam is greater than the thickness of the first floating beam. The end of the first floating beam away from the first main beam is connected to the elastic anchor. The first mounting surface, the second mounting surface, and the side surface are provided on the first main beam. The first strain gauge is attached and fixed to the first main beam. The vertical beam includes a second main beam fixed to the central platform and a second floating beam extending from the end of the second main beam away from the central platform toward the first cover plate. The thickness of the second main beam is greater than the thickness of the second floating beam. The end of the second floating beam away from the second main beam is fixed to the elastic anchor. The second main beam has a rectangular cross-section along its extension direction. The second main beam includes a third mounting surface and a fourth mounting surface parallel to the side surface. Two second strain gauges on the same vertical beam are respectively disposed on the third mounting surface and the fourth mounting surface. The elastic anchor includes a first fixing ring and a second fixing ring spaced apart from each other; the end of each first floating beam away from the first main beam is fixed to the second fixing ring; the end of each second floating beam away from the second main beam is fixed to the first fixing ring.

2. The force sensor according to claim 1, characterized in that, The two adjacent beams form a 120° angle along their length extensions.

3. The force sensor according to claim 1, characterized in that, The outer casing includes an inner wall facing the elastic anchor, and the outer peripheral side of the first fixing ring is attached to the inner wall; the surface of the first fixing ring facing the first cover plate is fixed to the first cover plate; The outer periphery of the second fixing ring is fixed to the inner wall.

4. The force sensor according to claim 3, characterized in that, The first fixing ring includes a first fixing ring body and three equally spaced fixing parts extending inward from the inner circumference of the first fixing ring body; the three fixing parts are connected to the three second floating beams one by one.

5. The force sensor according to claim 3, characterized in that, The second fixing ring is spaced apart from the second cover plate, and the second fixing ring is fixedly connected to the outer shell by bolts.

6. The force sensor according to claim 1, characterized in that, The central platform includes a hexagonal central platform body, a positioning hole formed by recessing the central platform body from the center position on the side near the second cover plate toward the direction away from the second cover plate, and a plurality of fixing holes formed by recessing the central platform body from the side near the second cover plate toward the direction away from the second cover plate; the plurality of fixing holes are evenly spaced on the outer periphery of the positioning hole. The second cover plate includes a second cover plate body, a boss protruding from the second cover plate body towards the side near the first cover plate, a positioning post protruding from the boss towards the side near the first cover plate, and a plurality of mounting holes formed through the second cover plate body and evenly distributed among each other; the boss is disposed on the side of the central platform body near the second cover plate, and the positioning post is disposed in the positioning hole; the plurality of mounting holes and the plurality of fixing holes are arranged opposite to each other, and are fixedly connected by a plurality of bolts passing through the plurality of mounting holes and the plurality of fixing holes in sequence.

7. The force sensor according to claim 6, characterized in that, The central platform also includes three connecting portions formed by the central platform body extending towards one side of the outer shell; one end of the three vertical beams near the second cover plate is fixed to the three connecting portions; wherein the three connecting portions and the three horizontal beams are respectively located on the six outer sides of the central platform body.

8. The force sensor according to claim 1, characterized in that, The distances between the first strain gauge and the second strain gauge and the central stage are both 0.5~1mm.

9. The force sensor according to claim 3, characterized in that, The gap between the second cover plate and the second fixing ring along their axial direction is 1~2mm.

10. The force sensor according to claim 1, characterized in that, The elastomer is made of any one of the following materials: aluminum alloy, magnesium alloy, titanium alloy, stainless steel, and PEEK polymer; the first cover plate, the outer shell, and the second cover plate are all made of any one of the following materials: aluminum alloy, magnesium alloy, titanium alloy, and stainless steel.

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