An adjustable angle force sensor calibration auxiliary device

Abstract

The present invention discloses an adjustable angle force sensor calibration auxiliary device, which is provided with a sphere and a cover to form an upper and lower hemispherical head plane symmetrically arranged on the periphery of the sphere; and a plurality of retractable sliding mechanisms are respectively provided on the side of the upper and lower hemispherical head planes that are in contact with the middle sphere. In the above manner, the present invention combines the advantages of the point-to-surface contact method in the existing force sensor calibration process, which can well ensure the verticality, and the surface-to-surface contact can reduce the unit force, so that in the stage of assembling the force sensor, the free sliding of the retractable sliding mechanism under the action of gravity can realize the automatic adjustment of the verticality of the pressure calibration, ensuring that the upper hemispherical head plane always remains horizontal when the calibration device is subjected to pressure; in the case of pressure detection, it can also ensure that the upper and lower hemispherical head planes and the middle sphere achieve perfect surface-to-surface contact during the calibration process, effectively reducing the unit area force of the tooling; and after the test is completed, the device is prevented from sticking, and the tooling is convenient to disassemble.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical measurement, and in particular to a calibration auxiliary device for an adjustable angle force sensor. Background Art

[0002] Force sensors are mainly used for various load tests. The accuracy of their values ​​directly affects the test results. Therefore, it is particularly important to trace their precise values. When conducting force sensor verification / calibration traceability, it is necessary to perform bidirectional measurements on the tension and compression directions of the force sensor. Especially when conducting compression verification / calibration of large-tonnage force sensors, since the loaded force value is very large, there are high requirements for the verticality of the force sensor installation. If there is an inclination angle: first, it affects the sensor verification accuracy; second, during the force loading process, if the inclination angle is too large, the lateral force is greater than the vertical force, and accidents are likely to occur, which may damage the force sensor at the least and cause safety accidents at the worst.

[0003] The force sensor calibration auxiliary device is an important tooling for calibrating force sensors. At present, there are two main structures used for the pressure calibration of force sensors: first, the point-to-surface contact form, with a small contact surface and large force per unit area. With the continuous increase in the range of force sensors, if the point-to-surface contact method is continued, the following situations may occur: the contact point is subjected to excessive force, resulting in deformation of the ball head or contact surface, grooves or spherical deformation, and damage to the original point-to-surface contact structure. Over time, the long-term accumulation leads to an inclination angle between the point-to-surface contact tooling and the sensor, which affects the measurement accuracy of the force sensor in the lightest case and collapses the sensor in the worst case. Second, the surface-to-surface contact form, with a large contact surface and small force per unit area, the force sensor pressure tooling is not easy to deform. However, due to the large contact surface, the surface-to-surface contact structure is difficult to adjust the verticality, which easily affects the measurement accuracy. And with the increase in the range of the force sensor, after the calibration is completed, the tooling is prone to adhesion, affecting disassembly.

[0004] Faced with this situation, there is an urgent need to provide an improved force sensor calibration auxiliary device to solve the above problems. Summary of the invention

[0005] The object of the present invention is to provide a force sensor compression calibration auxiliary device which can automatically adjust the verticality between the calibration tool and the force sensor, so as to effectively avoid various calibration problems caused by the tilt angle when performing compression measurement on the force sensor.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] An adjustable angle force sensor calibration auxiliary device, the device comprising:

[0008] The sphere and the cover are arranged on the upper hemispherical head plane and the lower hemispherical head plane which are symmetrically arranged on the periphery of the sphere;

[0009] A plurality of retractable sliding mechanisms are respectively provided on the side where the upper hemispherical head plane and the lower hemispherical head plane contact the sphere in the middle;

[0010] When the telescopic sliding mechanism is in an extended state, the upper hemispherical head plane and the lower hemispherical head plane can slide freely around the outer wall of the sphere;

[0011] When the telescopic sliding mechanism is in a retracted state, the upper hemispherical head plane, the sphere and the lower hemispherical head plane can form a solid cuboid.

[0012] As a further improvement of the present invention, the plurality of retractable sliding mechanisms are evenly embedded at the same circumference on the arc-shaped inner wall of the upper hemispherical head plane and the lower hemispherical head plane; and the plurality of retractable sliding mechanisms located at the same circumference are symmetrically distributed.

[0013] As a further improvement of the present invention, the number of the retractable sliding mechanisms is ≥ 8; wherein,

[0014] The number of the retractable sliding mechanisms provided on the arc-shaped inner wall of the upper hemispherical head plane is ≥ 4;

[0015] The number of the retractable sliding mechanisms arranged on the arc-shaped inner wall of the lower hemispherical head plane is ≥4.

[0016] As a further improvement of the present invention, the retractable sliding mechanism is provided with 8 pieces; wherein,

[0017] Four retractable sliding mechanisms are respectively arranged on the arc-shaped inner walls of the upper hemispherical head plane and the lower hemispherical head plane.

[0018] As a further improvement of the present invention, the same circumference on the arc-shaped inner wall is located at 1 / 2 of the radius of the arc surface of the upper hemispherical head plane and the lower hemispherical head plane respectively.

[0019] As a further improvement of the present invention, the telescopic sliding mechanism arranged on the planar arc-shaped inner wall of the upper hemispherical head and the telescopic sliding mechanism arranged on the planar arc-shaped inner wall of the lower hemispherical head are symmetrically distributed.

[0020] As a further improvement of the present invention, the retractable sliding mechanism comprises:

[0021] A spring embedded in the upper hemispherical head plane and the arc-shaped inner wall of the lower hemispherical head plane and a ball bearing connected to the end of the spring.

[0022] As a further improvement of the present invention, a plurality of grooves adapted to the spring and the ball bearing are provided on the arc-shaped inner walls of the upper hemispherical head plane and the lower hemispherical head plane.

[0023] As a further improvement of the present invention, the groove is opened in the vertical direction.

[0024] As a further improvement of the present invention, the starting end of the spring is connected to the bottom of the groove.

[0025] Technical effects and advantages of the present invention:

[0026] The adjustable angle force sensor calibration auxiliary device of the present invention is provided with an upper hemispherical head plane and a lower hemispherical head plane symmetrically arranged on the periphery of the sphere by arranging a sphere and a cover; and a plurality of retractable sliding mechanisms are respectively arranged on the side where the upper and lower hemispherical head planes contact the middle sphere; so that when the retractable sliding mechanisms are in an extended state, the upper hemispherical head plane and the lower hemispherical head plane can slide freely around the outer wall of the sphere; and when the retractable sliding mechanisms are in a retracted state, the upper hemispherical head plane, the sphere and the lower hemispherical head plane can be in close contact with each other to form a solid cuboid. Through the above method, the present invention combines the two advantages of the existing point-to-surface contact method in the force sensor calibration process, which can well ensure verticality and the surface-to-surface contact can reduce the unit force. In the stage of assembling the force sensor, the free sliding of the retractable sliding mechanism under the action of gravity can be used to achieve automatic adjustment of the verticality of the pressure calibration, ensuring that the plane of the upper hemisphere head always remains horizontal when the calibration device is subjected to pressure. At the same time, during pressure testing, it can ensure that the upper and lower hemisphere head planes achieve perfect surface-to-surface contact with the middle sphere during the calibration process, effectively reducing the force per unit area of ​​the tooling; and after the test is completed, it can also effectively avoid adhesion of the device, further facilitating the disassembly of the tooling.

[0027] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic cross-sectional view of the overall structure of the adjustable angle force sensor calibration auxiliary device of the present invention;

[0029] Figure 2 It is a structural schematic diagram of the telescopic sliding mechanism embedded in the plane of the upper hemispherical head of the present invention.

[0030] Figure numerals: 1, sphere; 2, upper hemispherical head plane; 3, lower hemispherical head plane; 4, spring; 5, ball bearing. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The present invention is directed to the following problems existing in the existing force sensor pressure calibration auxiliary device: the point-to-surface contact type calibration device has extremely high requirements on indicators such as material hardness, otherwise grooves or spherical deformation are likely to occur, causing damage to the original point-to-surface contact structure and affecting the verticality. The surface-to-surface contact structure type calibration device requires a large external force when installing and adjusting the verticality of the force sensor due to the large contact area, and as the force sensor range increases, adhesion is likely to occur. A new structure of a force sensor pressure calibration auxiliary device that can automatically adjust the verticality between a calibration tool and a force sensor is proposed. The adjustable angle force sensor calibration auxiliary device mainly consists of three parts, namely, an upper hemisphere head plane 2, a sphere 1, and a lower hemisphere head plane 3. Please refer to Figure 1 As shown in the cross-sectional structural diagram, the device comprises: a sphere 1 and an upper hemispherical head plane 2 and a lower hemispherical head plane 3 which are symmetrically arranged on the periphery of the sphere 1; wherein the interior of the upper hemispherical head plane 2 and the lower hemispherical head plane 3 can both be provided with arc-shaped grooves adapted to the outer periphery of the middle sphere 1; in addition, the arc surfaces of the upper hemispherical head plane 2 and the lower hemispherical head plane 3 are also provided with a plurality of retractable sliding mechanisms; which can be combined with Figure 2 As shown, when the telescopic sliding mechanism is in an extended state, the upper hemispherical head plane 2 and the lower hemispherical head plane 3 can slide freely around the outer wall of the sphere 1 under the action of gravity; when the telescopic sliding mechanism is in a contracted state, the upper hemispherical head plane 2, the sphere 1 and the lower hemispherical head plane 3 can achieve full surface contact with each other and form a solid rectangular parallelepiped together. When the force sensor is actually pressed, the force value generated by the calibration device acts vertically on the upper hemispherical head plane 2, and the lower end of the lower hemispherical head plane 3 can be connected to the force sensor through a thread.

[0033] Specifically, four or more retractable sliding mechanisms may be evenly embedded on the same circumference inside the upper hemispherical head plane 2 at a position half the radius of the arc surface, and the retractable sliding mechanisms located on the same circumference are preferably distributed symmetrically.

[0034] Specifically, the telescopic sliding mechanism can be configured as a spring 4 embedded in the arc-shaped inner wall of the upper hemispherical head plane 2 and a ball bearing 5 connected to the end of the spring 4. The position of the ball bearing 5 can be adjusted by the expansion and contraction of the spring 4. Correspondingly, the arc-shaped inner walls of the upper hemispherical head plane 2 and the lower hemispherical head plane 3 are provided with a plurality of grooves adapted to the spring 4 and the ball bearing 5. The grooves can be provided vertically, and the beginning of the spring 4 is connected to the bottom of the groove. In this way, the ball bearing 5 can protrude from the inner surface of the upper hemispherical head plane 2 under the action of the spring 4 when not under pressure. It has been verified by experiments that by evenly and symmetrically arranging four sets of telescopic sliding mechanisms at the same height, the center of gravity position can be adjusted well, ensuring that the center of gravity positions of the "upper hemispherical head plane 2" and the "ball 1" are consistent. After adjustment, under stress, the ball bearing 5 squeezes the spring 4. At this time, the ball bearing 5 will be completely recessed into the interior of the upper hemispherical head plane 2, ensuring that the "upper hemispherical head plane 2" and the "ball 1" achieve surface contact, avoiding excessive stress and deformation of the contact point due to point-to-surface contact.

[0035] Similarly, the same position inside the lower hemispherical head plane 3 can adopt the same structure as that inside the upper hemispherical head plane 2, and four sets of ball bearings 5 ​​are also embedded, and the up and down movement is controlled by the spring 4.

[0036] In this way, under the interaction of the eight sets of retractable sliding mechanisms in the upper and lower parts, even if the force sensor is at a certain angle after assembly, it can achieve a vertical calibration state through the automatic sliding adjustment between the ball bearings 5, avoiding the influence of the tilt angle on the sensor pressure calibration. This is because when the ball head plane is not subjected to force, the ball bearing 5 protrudes from the inner surface of the ball head under the control of the spring 4, and the eight sliding ball bearings 5 ​​in the upper and lower ball heads can automatically adjust the center of gravity under the action of gravity to ensure verticality. After adjusting the position, the force value is applied to the upper hemisphere head plane 2, and the ball bearing 5 is subjected to force and enters the groove structure, ensuring that the entire calibration process is surface-to-surface contact.

[0037] It can be seen that the present invention combines the advantages of the point-to-surface contact method in the force sensor calibration process, which can well ensure verticality, and the surface-to-surface contact method, which can reduce unit force.

[0038] First, during the force sensor assembly phase, the eight sets of ball bearings 5 ​​are freely slid to automatically adjust the center of gravity to ensure verticality, thus completing the preparation work for force sensor calibration.

[0039] Secondly, after the force sensor is assembled, the force loading system acts on the upper hemispherical head plane 2, and the eight ball bearings 5 ​​are pressed into the concave structure, ensuring perfect surface-to-surface contact during the calibration process, effectively reducing the force per unit area of ​​the tooling.

[0040] Furthermore, after the force loading system is unloaded, the spring + ball bearing arrangement structure can avoid the sticking phenomenon existing in the traditional surface-to-surface structure, and the spring 4 lifts up the ball bearing 5, making it easy to disassemble the tooling.

[0041] At the same time, in order to further verify the feasibility of the design device, the present invention designed the following simulation experiment. On a horizontal platform, under no force, the horizontality of the upper hemispherical head plane 2 was tested using a level measuring instrument and an inclinometer, and each time one side of the lower hemispherical head plane 3 was padded by 0.5mm, divided into four groups, with a total padding of 2mm. After each padding is stable, the ball 1 and the upper hemispherical head plane 2 are installed. Under the action of gravity, the upper hemispherical head plane 2, the ball 1, and the lower hemispherical head plane 3 quickly achieve self-adjustment. After reaching a stable state, the horizontality of the upper hemispherical head surface 2 is tested again using a level measuring instrument and an inclinometer. The final test results show that the four artificial tilt angle settings have reduced the horizontal tilt angle of the upper hemispherical head plane 2 by more than 10 times compared to when the retractable sliding mechanism is not installed, effectively improving the verticality level of the pressure-direction calibration force sensor (that is, ensuring that the calibration auxiliary device always remains in the vertical direction when subjected to pressure).

[0042] To summarize, the adjustable angle force sensor calibration auxiliary device of the present invention is configured by arranging an upper hemispherical head plane and a lower hemispherical head plane that are symmetrically arranged on the periphery of the sphere and a cover; and arranging a plurality of retractable sliding mechanisms on the side where the upper and lower hemispherical head planes are in contact with the middle sphere; so that when the retractable sliding mechanisms are in an extended state, the upper hemispherical head plane and the lower hemispherical head plane can slide freely around the outer wall of the sphere; and when the retractable sliding mechanisms are in a contracted state, the upper hemispherical head plane, the sphere and the lower hemispherical head plane can be in close contact with each other to form a solid cuboid. Through the above method, the present invention combines the two advantages of the existing point-to-surface contact method in the force sensor calibration process, which can well ensure verticality and the surface-to-surface contact can reduce the unit force. In the stage of assembling the force sensor, the free sliding of the retractable sliding mechanism under the action of gravity can be used to achieve automatic adjustment of the verticality of the pressure calibration, ensuring that the plane of the upper hemisphere head always remains horizontal when the calibration device is subjected to pressure. At the same time, during pressure testing, it can ensure that the upper and lower hemisphere head planes achieve perfect surface-to-surface contact with the middle sphere during the calibration process, effectively reducing the force per unit area of ​​the tooling; and after the test is completed, it can also effectively avoid adhesion of the device, further facilitating the disassembly of the tooling.

[0043] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An adjustable angle force sensor calibration auxiliary device, characterized in that: The device comprises: The sphere (1) and the cover are arranged on an upper hemispherical head plane (2) and a lower hemispherical head plane (3) which are symmetrically arranged on the periphery of the sphere (1); A plurality of retractable sliding mechanisms are respectively provided on the sides of the upper hemispherical head plane (2) and the lower hemispherical head plane (3) that are in contact with the middle sphere (1); When the telescopic sliding mechanism is in an extended state, the upper hemispherical head plane (2) and the lower hemispherical head plane (3) can slide freely around the outer wall of the sphere (1); When the telescopic sliding mechanism is in a retracted state, the upper hemispherical head plane (2), the sphere (1) and the lower hemispherical head plane (3) can form a solid rectangular parallelepiped; the telescopic sliding mechanism comprises: a spring (4) embedded in the arc-shaped inner walls of the upper hemispherical head plane (2) and the lower hemispherical head plane (3), and a ball bearing (5) connected to the end of the spring (4).

2. The adjustable angle force sensor calibration auxiliary device according to claim 1, characterized in that: The plurality of telescopic sliding mechanisms are evenly embedded in the same circumference on the arc-shaped inner wall of the upper hemispherical head plane (2) and the lower hemispherical head plane (3); and the plurality of telescopic sliding mechanisms located at the same circumference are symmetrically distributed.

3. The adjustable angle force sensor calibration auxiliary device according to claim 1 or 2, characterized in that: The number of the retractable sliding mechanisms is ≥ 8; wherein, The number of retractable sliding mechanisms provided on the arc-shaped inner wall of the upper hemispherical head plane (2) is ≥4; The number of retractable sliding mechanisms arranged on the arc-shaped inner wall of the lower hemispherical head plane (3) is ≥4.

4. The adjustable angle force sensor calibration auxiliary device according to claim 3, characterized in that: The retractable sliding mechanism is provided with 8 pieces; among which, Four retractable sliding mechanisms are respectively arranged on the arc-shaped inner walls of the upper hemispherical head plane (2) and the lower hemispherical head plane (3).

5. The adjustable angle force sensor calibration auxiliary device according to claim 2, characterized in that: The same circumference on the arc-shaped inner wall is located at 1 / 2 of the radius of the arc surface of the upper hemispherical head plane (2) and the lower hemispherical head plane (3).

6. The adjustable angle force sensor calibration auxiliary device according to claim 2, characterized in that: The telescopic sliding mechanism arranged on the arc-shaped inner wall of the upper hemispherical head plane (2) and the telescopic sliding mechanism arranged on the arc-shaped inner wall of the lower hemispherical head plane (3) are symmetrically distributed.

7. The adjustable angle force sensor calibration auxiliary device according to claim 1, characterized in that: A plurality of grooves adapted to the spring (4) and the ball bearing (5) are provided on the arc-shaped inner walls of the upper hemispherical head plane (2) and the lower hemispherical head plane (3).

8. The adjustable angle force sensor calibration auxiliary device according to claim 7, characterized in that: The groove is opened vertically.

9. The adjustable angle force sensor calibration auxiliary device according to claim 8, characterized in that: The starting end of the spring (4) is connected to the bottom of the groove.

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