Six-dimensional force sensor

Abstract

The invention discloses a six-dimensional force sensor, and belongs to the technical field of sensors. Comprising an outer ring body, a center table and three connecting columns which are integrally formed. A blind hole is formed in the axis of the connecting column, an overload rod is installed in the blind hole, and an annular gap is formed between the middle of the overload rod and the inner wall of the blind hole. The middle part of the connecting column is provided with an annular sinking groove, and a strain gauge is pasted in the annular sinking groove. A connecting disc is fixed on the upper end surface of the center table; an arc-shaped mounting table is arranged on the inner wall of the outer ring body, and a plurality of distance sensors evenly distributed around the axis of the outer ring body are mounted on the arc-shaped mounting table and used for detecting the position of the connecting disc. According to the invention, the middle part of the connecting column is provided with the annular sinking groove to form an elastic body, so that the connecting column mainly generates controllable elastic deformation in a specific area when being stressed, thereby cooperating with the strain gauges on the four side surfaces, and deducing a six-dimensional force acting on the sensor; when the sensor bears a large force, the overload rod can reduce the deformation amount of the elastic body, thereby preventing the strain gauge from being damaged due to excessive deformation.

Description

Technical Field

[0001] The present invention relates to the technical field of sensors, and particularly to a six - dimensional force sensor. Background Art

[0002] In the fields of industrial automation, robotics, aerospace, and automotive manufacturing, etc., the demand for six - dimensional force sensors is increasing day by day. A six - dimensional force sensor can simultaneously measure the normal stresses in three directions and the shear stresses in three directions, providing key data for the dynamic control and performance evaluation of mechanical systems.

[0003] The elastic deformation ability of the sensor is crucial for accurate measurement. Traditional six - dimensional force sensors have insufficient deformation ability in specific directions, resulting in reduced measurement sensitivity; in addition, in practical applications, the sensor may be subjected to forces beyond its design range, causing damage to internal components. Summary of the Invention

[0004] Aiming at the above - mentioned existing technical deficiencies, the present invention provides a six - dimensional force sensor.

[0005] The present invention adopts the following technical solutions: A six - dimensional force sensor includes an integrally formed outer ring body, a central platform, and three connecting columns; the central platform is located at the axis center of the outer ring body, and the connecting columns are evenly connected between the outer ring body and the central platform; A blind hole is provided at the axis center of the connecting column, the outer end of the blind hole communicates with the outer peripheral surface of the outer ring body, and an overload rod is installed in the blind hole; both ends of the overload rod abut against both ends of the blind hole, and there is an annular gap between the middle part of the overload rod and the inner wall of the blind hole; an annular sunk groove is provided in the middle part of the connecting column, and a strain gauge is pasted in the annular sunk groove; A connecting disc is fixed on the upper end surface of the central platform; arc - shaped mounting platforms are arranged around the axis center of the outer ring body on the inner wall of the outer ring body, and a plurality of distance sensors evenly distributed around the axis center of the outer ring body are installed on the arc - shaped mounting platforms; the distance sensors are parallel to the axis center of the outer ring body, and the distance sensors are opposite to the edge of the connecting disc.

[0006] Further, the inner end of the blind hole has an inner stepped hole, and the outer end of the blind hole has an outer stepped hole; the inner end of the overload rod has an inner positioning platform that cooperates with the inner stepped hole, and the outer end of the overload rod has an outer positioning platform that cooperates with the outer stepped hole.

[0007] A counterbore is provided at the outer end of the overload rod, a sliding column is slidably connected in the counterbore, and one end of the sliding column away from the overload rod has a threaded column; A retaining ring is fixed at the outer end of the overload rod, the threaded column passes through the center of the retaining ring; an elastic sheet is sleeved on the threaded column, and the elastic sheet is located between the sliding column and the retaining ring; A fixing seat fixed to the outer wall of the outer ring is provided on the outer end side of the blind hole. A threaded hole is provided on the fixing seat, and the end of the threaded column away from the sliding column is installed in the threaded hole.

[0008] The outer end of the blind hole is an installation plane opened on the outer wall of the outer ring. Through grooves penetrating the outer ring are provided on the upper and lower sides of the installation plane; Both ends of the fixing seat are fixedly supported on the installation plane, and there is a gap between the middle part of the fixing seat and the installation plane.

[0009] The cross-section of the connecting column is square, and strain gauges are attached to all four side surfaces of the annular sunk groove. The annular sunk groove is centered relative to the annular gap.

[0010] Three arc-shaped mounting platforms are provided. The three arc-shaped mounting platforms and the three connecting columns are staggered and evenly distributed; two distance sensors are installed on each arc-shaped mounting platform.

[0011] A gap is left between the periphery of the connecting disk and the inner wall of the outer ring. A ring-shaped platform opposite to the distance sensors is provided at the edge position of the lower side surface of the connecting disk.

[0012] A main board is fixed to the lower end surface of the central platform; a wire passing hole is provided on the outer ring, and a wire passing pipe is installed in the wire passing hole.

[0013] A flange ring is fixed to the lower end of the outer ring; the outer ring of the flange ring is fixedly connected to the outer ring by bolts. The inner ring of the flange ring is thicker than the outer ring of the flange ring, and evenly distributed connecting holes are provided on the inner ring of the flange ring.

[0014] The central hole of the flange ring is larger than the main board, and a cover plate is installed at the central hole of the flange ring.

[0015] The beneficial effects of the present invention are as follows: The integral molding of the outer ring, the central platform and the connecting column enhances the overall rigidity and stability of the sensor and reduces the assembly error; the connecting column adopts a square cross-section, and an annular sunk groove is provided in the middle to form an elastic body, so that the connecting column mainly undergoes controllable elastic deformation in this specific area when stressed, thereby cooperating with the strain gauges on the four side surfaces to deduce the six-dimensional force acting on the sensor; the overload rod plays an overload protection role for the connecting column. When the central platform is stressed greatly, the overload rod can reduce the deformation amount of the elastic body, thereby preventing the strain gauges from being damaged due to excessive deformation; the present invention can further improve the accuracy of six-dimensional force measurement by installing six distance sensors to detect the position change of the connecting disk relative to the outer ring in real time. Description of the Drawings

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0017] Figure 1 It is a perspective view of a six-axis force sensor of the present invention.

[0018] Figure 2 It is a top view of a six-axis force sensor of the present invention.

[0019] Figure 3 It is an exploded view of a six-axis force sensor of the present invention Figure 1 .

[0020] Figure 4 It is an exploded view of a six-axis force sensor of the present invention Figure 2 .

[0021] Figure 5 It is Figure 2 the sectional view taken along A-A in

[0022] Figure 6 It is Figure 5 the installation schematic diagram of the overload rod at position B in

[0023] Figure 7 It is the assembly schematic diagram of the overload rod on one side in the present invention.

[0024] Explanation of reference numerals: 1. Outer ring body; 11. Arc-shaped installation table; 12. Installation plane; 13. Through groove; 2. Central platform; 3. Connecting column; 31. Blind hole; 311. Inner stepped hole; 312. Outer stepped hole; 32. Annular gap; 33. Annular sink; 4. Overload rod; 41. Inner positioning table; 42. Outer positioning table; 43. Counterbore; 44. Slide column; 45. Threaded column; 46. Retaining ring; 47. Elastic sheet; 48. Fixed seat; 5. Strain gauge; 6. Connecting disc; 61. Annular platform; 7. Distance sensor; 8. Main board; 81. Cable passing tube; 9. Flange ring; 91. Cover plate. Detailed implementation manners

[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] Embodiment 1: As Figures 1 to 4 shown, the present invention provides a six-axis force sensor, which includes an integrally formed outer ring body 1, a central platform 2, and three connecting columns 3. The central platform 2 is located at the axis center of the outer ring body 1, and the connecting columns 3 are located at the radial position of the outer ring body 1. The three connecting columns 3 are connected between the outer ring body 1 and the central platform 2 and are evenly distributed around the axis of the outer ring body 1. A connecting disk 6 is fixed on the upper end surface of the central platform 2, and a flange ring 9 is fixed at the lower end of the outer ring body 1.

[0027] Combined with Figures 3 to 7 shown, the cross-section of the connecting column 3 is square. A blind hole 31 is provided at the axis center of the connecting column 3, and the outer end of the blind hole 31 communicates with the outer peripheral surface of the outer ring body 1. Installation planes 12 are provided at corresponding positions on the outer peripheral surface of the outer ring body 1, and the outer end of the blind hole 31 is located at the center of the installation plane 12. Through grooves 13 penetrating the outer ring body 1 are provided on the upper and lower sides of the installation plane 12, so that the upper and lower side surfaces of the outer end of the connecting column 3 are not connected to the outer ring body 1. An annular sunk groove 33 is provided in the middle of the connecting column 3, and the annular sunk groove 33 is also square. The size of the connecting column 3 at the annular sunk groove 33 is thinner, forming an elastomer that is easy to deform. Strain gauges 5 are attached to all four side surfaces of the annular sunk groove 33 for detecting the deformation amount of the elastomer. The connecting column 3 adopts a square cross-section and an annular sunk groove is provided in the middle, which not only enhances the elastic deformation ability of the connecting column in a specific direction, but also ensures the consistency and predictability of the deformation. The square cross-sectional shape reduces the deformation error caused by non-uniform stress, and the annular sunk groove serves as a stress concentration area, enabling the strain gauge to more accurately capture the deformation signal, improving the sensitivity and accuracy of the measurement.

[0028] Combined with Figures 3 to 7 shown, an overload rod 4 is installed in the blind hole 31. The middle part of the overload rod 4 is cylindrical, and there is an annular gap 32 between the middle part of the overload rod 4 and the inner wall of the blind hole 31. The annular sunk groove 33 in the middle of the connecting column 3 is basically aligned with the center of the annular gap 32, and the strain gauges 5 in the annular sunk groove 33 are also attached as close as possible to the center of each side surface of the annular sunk groove 33.

[0029] The inner end of the blind hole 31 has an inner stepped hole 311, and the outer end of the blind hole 31 has an outer stepped hole 312. Chamfered corners are provided at the right angles of the inner stepped hole 311 and the outer stepped hole 312. The inner end of the overload rod 4 has an inner positioning platform 41, and the outer end of the overload rod 4 has an outer positioning platform 42. Chamfered corners are also provided at the right angles of the inner positioning platform 41 and the outer positioning platform 42. The outer positioning platform 42 of the overload rod 4 has a longer length, and the outer positioning platform 42 is slidably installed in the outer stepped hole 312; the inner positioning platform 41 of the overload rod 4 has a shorter length, and the inner positioning platform 41 is installed in the inner stepped hole 311 with a clearance fit. The overload rod 4 is pressed inward by the sliding column 44 and the threaded column 45 provided at the outer end, so that the chamfered corners at the inner and outer ends of the blind hole 31 and the overload rod 4 are in contact, and the contact surface of the chamfered corners at the inner ends of the blind hole 31 and the overload rod 4 is smaller.

[0030] A counterbore 43 is provided at the axis of the outer end of the overload rod 4, and the sliding column 44 is slidably connected in the counterbore 43. The threaded column 45 and the sliding column 44 are of an integral structure. The retaining ring 46 is sleeved on the threaded column 45 and fixed to the outer end of the overload rod 4 by screws. The elastic piece 47 is sleeved on the threaded column 45 and abuts between the sliding column 44 and the retaining ring 46. The fixing seat 48 is provided with a threaded hole matching the sliding column 44, and the threaded column 45 is threadedly connected in the threaded hole. Both ends of the fixing seat 48 have a stepped structure, and both ends of the fixing seat 48 are fixed to the installation plane 12 by screws. By providing the stepped structure, a gap is formed between the middle part of the fixing seat 48 and the installation plane 12, reducing the deformation interference to the overall connecting column 3.

[0031] The overload rod 4 has a higher hardness than the annular sinking groove 33 part of the connecting column 3; when the force on the central platform 2 is small, the main deformation amount is reflected in the position of the annular sinking groove 33 of the connecting column 3. The annular sinking groove 33 part is more sensitive to force deformation, and the strain gauge can accurately detect this deformation amount and finally decouple the force on the central platform 2. Therefore, this sensor is more sensitive when the force is small; when the force on the central platform 2 is large (that is, after the deformation amount of the annular sinking groove 33 of the connecting column 3 exceeds a certain value), the overload rod 4 will also be deformed by force. At this time, the deformation amount of the annular sinking groove 33 part detected by the strain gauge also includes the force on the overload rod 4, greatly improving the overload capacity of the sensor and preventing the strain gauge from being damaged due to excessive deformation; however, since the annular sinking groove 33 part is no longer as sensitive to force deformation as before, the detection error of the sensor will increase to a certain extent; by selecting overload rods 4 with different hardnesses, a suitable trade-off can be made between overload protection and measurement accuracy.

[0032] Embodiment 2: On the basis of the above Embodiment 1, combined with Figures 3 to 6As shown, the middle part of the connecting plate 6 and the upper end face of the central platform 2 are fitted with a rabbet and fixedly connected by bolts. There is a ring of bosses on the upper side of the connecting plate 6, and connecting holes are provided in the bosses; the height of the bosses is higher than the bolts in the middle of the connecting plate 6, which is convenient for connecting the force-bearing members. A gap is left between the periphery of the connecting plate 6 and the inner wall of the outer ring body 1 to prevent the periphery of the connecting plate 6 from contacting the outer ring body 1 during the process of position change. A ring-shaped platform 61 is provided at a position near the edge of the lower side of the connecting plate 6.

[0033] On the inner wall of the outer ring body 1, there are three arc-shaped mounting platforms 11 arranged around the axis of the outer ring body 1. The arc-shaped mounting platforms 11 are integrally formed with the outer ring body 1, and the three arc-shaped mounting platforms 11 and the three connecting columns 3 are staggered and evenly distributed. Two mounting through holes are provided in each arc-shaped mounting platform 11, and distance sensors 7 are installed in the mounting through holes. The six distance sensors 7 are evenly distributed around the axis of the outer ring body 1. The upper ends of the distance sensors 7 are opposite to the edge of the connecting plate 6, and are used to detect the position change of the connecting plate 6 relative to the outer ring body 1 in real time. In this embodiment, the six distance sensors are used to detect the minute displacement change of the connecting plate relative to the outer ring body in real time. By calculating the displacement amounts of the connecting plate in various directions, the six-dimensional force acting on the sensors can be deduced, which not only improves the measurement accuracy, but also enhances the response ability of the sensors to complex force conditions; the distance sensors can cooperate with the strain gauges to confirm each other and improve the decoupling accuracy of the sensors, thereby improving the measurement accuracy.

[0034] Embodiment Three: On the basis of the above Embodiment Two, combined with Figures 1 to 5 As shown, a main board 8 is fixed to the lower end face of the central platform 2 by screws; a wire passing hole is provided on the side wall of the outer ring body 1, and a wire passing pipe 81 is installed in the wire passing hole, and the wire passes through the wire passing pipe 81 to connect the main board 8. The main board 8 is connected to each distance sensor 7 and the strain gauge 5, and transmits data to the outside through the wire.

[0035] The inner ring of the flange ring 9 is thicker than the outer ring of the flange ring 9. The outer ring of the flange ring 9 is fixedly connected to the outer ring body 1 by bolts; the inner ring of the flange ring 9 is provided with connecting holes, and the inner ring of the flange ring 9 is higher than the bolts on the outside, which is convenient for connecting with the connecting base parts. The size of the central hole of the flange ring 9 is larger than that of the main board 8, and a cover plate 91 is buckled and installed at the central hole of the flange ring 9, which is convenient for maintaining the main board 8. The bosses and connecting holes on the connecting plate are convenient for connecting with the force-bearing members, and the structure of the flange ring is convenient for the sensors to be fixed to the connecting base parts by bolts, which is convenient for installing the sensors; the cover plate is buckled at the central hole of the flange ring, making the maintenance of the main board more convenient; when it is necessary to repair or replace the main board, only the cover plate needs to be disassembled for operation, and there is no need to disassemble the whole sensor.

[0036] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A six-dimensional force sensor, comprising an outer ring body (1), a center platform (2) and three connecting columns (3) formed in one piece; the center platform (2) is located at the axis of the outer ring body (1), and the connecting columns (3) are evenly connected between the outer ring body (1) and the center platform (2); Features: The connecting column (3) is provided with a blind hole (31) at its axis, the outer end of the blind hole (31) is connected to the outer peripheral surface of the outer ring body (1), and an overload rod (4) is installed in the blind hole (31); the two ends of the overload rod (4) are abutted against the two ends of the blind hole (31), and an annular gap (32) is provided between the middle of the overload rod (4) and the inner wall of the blind hole (31); the connecting column (3) is provided with an annular groove (33) in the middle, and a strain gauge (5) is attached to the annular groove (33); A connection plate (6) is fixed to the upper end surface of the center platform (2); an arc-shaped mounting platform (11) is arranged on the inner wall of the outer ring body (1) around the axis of the outer ring body (1); a plurality of distance sensors (7) evenly distributed around the axis of the outer ring body (1) are mounted on the arc-shaped mounting platform (11); the distance sensors (7) are parallel to the axis of the outer ring body (1), and the distance sensors (7) are opposite to the edge of the connection plate (6).

2. A six-dimensional force sensor according to claim 1, characterized in that: The inner end of the blind hole (31) has an inner step hole (311), and the outer end of the blind hole (31) has an outer step hole (312); the inner end of the overload rod (4) has an inner positioning platform (41) that matches the inner step hole (311), and the outer end of the overload rod (4) has an outer positioning platform (42) that matches the outer step hole (312).

3. A six-dimensional force sensor according to claim 2, characterized in that: The outer end of the overload rod (4) is provided with a countersunk hole (43), a sliding column (44) is slidably connected in the countersunk hole (43), and the end of the sliding column (44) away from the overload rod (4) has a threaded column (45); A retaining ring (46) is fixed to the outer end of the overload rod (4), and the threaded column (45) is arranged through the center of the retaining ring (46); an elastic sheet (47) is sleeved on the threaded column (45), and the elastic sheet (47) is located between the sliding column (44) and the retaining ring (46); A fixing seat (48) fixed to the outer wall of the outer ring body (1) is provided on the outer end side of the blind hole (31), and a threaded hole is provided on the fixing seat (48), and an end of the threaded column (45) away from the sliding column (44) is installed in the threaded hole.

4. A six-dimensional force sensor according to claim 3, characterized in that: The outer end of the blind hole (31) is a mounting plane (12) formed on the outer wall of the outer ring body (1), and the upper and lower sides of the mounting plane (12) are provided with through grooves (13) penetrating the outer ring body (1); Both ends of the fixing seat (48) are fixedly supported on the mounting plane (12), and a gap is provided between the middle portion of the fixing seat (48) and the mounting plane (12).

5. The six-dimensional force sensor according to claim 1, characterized in that: The cross section of the connecting column (3) is square, and strain gauges (5) are attached to the four side surfaces of the annular recess (33), and the annular recess (33) is opposite to the center of the annular gap (32).

6. A six-dimensional force sensor according to claim 1, characterized in that: Three arc-shaped mounting platforms (11) are provided, and the three arc-shaped mounting platforms (11) and the three connecting columns (3) are evenly distributed in an alternating manner; and two distance sensors (7) are installed on each arc-shaped mounting platform (11).

7. A six-dimensional force sensor according to claim 6, characterized in that: A gap is left between the periphery of the connection disk (6) and the inner wall of the outer ring body (1), and a ring-shaped platform (61) is provided at the edge of the lower side of the connection disk (6) and is opposite to the distance sensor (7).

8. The six-dimensional force sensor according to claim 1, characterized in that: A main board (8) is fixed to the lower end surface of the center platform (2); a wire passing hole is provided on the outer ring body (1), and a wire passing tube (81) is installed in the wire passing hole.

9. A six-dimensional force sensor according to claim 8, characterized in that: A flange ring (9) is fixed to the lower end of the outer ring body (1); the outer ring of the flange ring (9) is fixedly connected to the outer ring body (1) by bolts, the inner ring of the flange ring (9) is thicker than the outer ring of the flange ring (9), and the inner ring of the flange ring (9) is provided with evenly distributed connection holes.

10. A six-dimensional force sensor according to claim 9, characterized in that: The center hole of the flange ring (9) is larger than the main board (8), and a cover plate (91) is installed at the center hole of the flange ring (9).

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