Vibrating wire strain gauge automatic calibration device and method with force value monitoring function

Abstract

The invention discloses a vibrating wire strain gauge automatic calibration device with a force value monitoring function, and relates to the field of measuring instrument calibration, the vibrating wire strain gauge automatic calibration device comprises a fixing assembly fixedly connected to a bottom plate, the fixing assembly comprises a first fixing frame and a second fixing frame which are arranged at an interval in the length direction of the bottom plate, and two guide shafts are connected between the two fixing frames; moving assemblies are arranged on the two guide shafts in a linear reciprocating sliding mode. The moving assembly and the first fixing frame are oppositely provided with at least one pair of clamping assemblies which are matched with each other, and the clamping assemblies are used for clamping a to-be-tested vibrating wire strain gauge. The side, facing the first fixing frame, of the moving assembly is connected with a displacement sensor, and the side, deviating from the first fixing frame, of the moving assembly is connected with a driving assembly driving the moving assembly to be close to or away from the first fixing frame. The vibrating wire strain gauge calibration device and method have the advantages of large output force value, high displacement precision, high calibration speed, good safety performance, high applicability and the like, and can meet the calibration requirements of vibrating wire strain gauges of different sizes.

Description

Technical Field

[0001] The invention belongs to the field of measuring instrument calibration, and in particular relates to an automatic calibration device and method for a vibrating-wire strain gauge with a force value monitoring function, which is mainly used for detection and calibration of the vibrating-wire strain gauge. Background Art

[0002] Vibrating-wire strain gauge is a strain sensor that uses a vibrating wire for measurement. It has the advantages of simple structure, reliable measurement results, and high measurement accuracy. It is widely used in civil engineering and other fields. Vibrating-wire strain gauges are suitable for long-term burial in hydraulic structures or other concrete structures. The deformation of the measured structure will synchronously change the frequency of the vibrating wire in the vibrating-wire strain gauge, thereby measuring the strain value of the structure.

[0003] Most of the existing vibrating-wire strain gauge calibration devices are manually operated, and it is difficult to accurately control the strain of the vibrating-wire strain gauge being measured; the measurement personnel cannot know the force value applied to the vibrating-wire strain gauge being measured during the calibration process. If the force exceeds the limit strain of the vibrating-wire strain gauge being measured, the vibrating-wire strain gauge or even the calibration device will be damaged; the stress required for some vibrating-wire strain gauges to produce sufficient strain is too large, which is far beyond the manual operation of the measurement personnel; when calibrating vibrating-wire strain gauges with different gauge lengths, it is necessary to manually adjust the position of the micrometer, which is inefficient; the fixture used in the existing vibrating-wire strain gauge calibration device cannot avoid the sliding of the vibrating-wire strain gauge being measured, and the measurement accuracy is difficult to guarantee.

[0004] Therefore, providing a safe, reliable and highly accurate vibrating-wire strain gauge automatic calibration device and method with a force value monitoring function has become a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0005] The object of the present invention is to provide a vibrating-wire strain gauge automatic calibration device and method with a force value monitoring function, so as to solve the above-mentioned technical problems existing in the prior art.

[0006] To achieve the above-mentioned purpose, in one aspect, the present invention provides an automatic calibration device for a vibrating-wire strain gauge with a force value monitoring function, comprising a fixed component fixed to a base plate, the fixed component comprising a first fixed frame and a second fixed frame spaced apart along the length direction of the base plate, two guide shafts being connected between the first fixed frame and the second fixed frame, and a moving component being linearly reciprocatingly slid on the two guide shafts; at least one pair of mutually cooperating clamping components are installed facing each other on the moving component and the first fixed frame, for clamping the vibrating-wire strain gauge to be measured; a displacement sensor is connected to a side of the moving component facing the first fixed frame, and a driving component for driving the moving component to move closer to or away from the first fixed frame is connected to a side of the moving component away from the first fixed frame.

[0007] In some possible implementations of the present invention, the clamping assembly includes a clamping base, a front clamping knob, and a rear clamping knob, and the front clamping knob and the rear clamping knob clamp the end seat of the vibrating wire strain gauge to be measured in the clamping base. The clamping assembly of the above structure can prevent the vibrating wire strain gauge to be measured from sliding, improve the calibration accuracy, and can adapt to the end seat thickness of different vibrating wire strain gauges to be measured, thereby improving applicability.

[0008] In some possible implementations of the present invention, a pair of two mutually cooperating clamping assemblies are displaced on the same axis, and the front walls of the clamping bases in the two clamping assemblies are opposite to each other.

[0009] In some possible implementations of the present invention, the moving assembly includes a displacement platform, a through hole is provided on each side of the displacement platform, the two guide shafts pass through the two through holes, a protruding mounting seat is provided at one end of the displacement platform, a tension and pressure sensor is fixed on the protruding mounting seat, and the tension and pressure sensor is connected to the driving assembly. The tension and pressure sensor can monitor the force value applied by the working shaft of the electric cylinder on the displacement platform in real time to avoid damaging the vibrating wire strain gauge being measured due to exceeding the stress range.

[0010] In some possible implementations of the present invention, linear bearings are further provided between both ends of the through hole and the guide shaft.

[0011] In some possible implementations of the present invention, the displacement sensor is fixed on a base plate, and a probe of the displacement sensor is connected to the moving component.

[0012] In some possible implementations of the present invention, the displacement sensor is located on the central plane of the displacement platform, contacts the inner side of the displacement platform and moves along with the displacement platform to prevent the displacement platform from swinging and affecting the displacement measurement accuracy.

[0013] In some possible implementations of the present invention, the driving assembly includes a motor support, an electric cylinder and a servo motor. The motor support and the electric cylinder are fixed to one end of the bottom plate away from the first fixing frame. The servo motor is fixed to the motor support. The output shaft of the servo motor is fixed to one end of the electric cylinder. The servo motor cooperates with the electric cylinder to generate displacement, and maintains high displacement accuracy when a large pulling pressure is obtained.

[0014] In some possible implementations of the present invention, a connecting column is connected to one end of the electric cylinder away from the servo motor, and both ends of the connecting column are provided with external threads, which are respectively threadedly connected to the shaft end of the electric cylinder and the center through hole of the tension and pressure sensor.

[0015] In some possible implementations of the present invention, two second fixing brackets are provided, and the two second fixing brackets are fixed on the left and right sides of the middle of the bottom plate.

[0016] In another aspect, the present invention further provides a method for automatic calibration of a vibrating-wire strain gauge, using any of the above-mentioned automatic calibration devices for vibrating-wire strain gauges with a force value monitoring function, comprising the following steps:

[0017] Step S1, adjusting the distance between the displacement platform and the first fixed frame to ensure that the end seat of the vibrating wire strain gauge can be placed in the clamping base;

[0018] Step S2, recording the frequency value of the vibrating wire strain gauge in the relaxed state as the center frequency;

[0019] Step S3, fixing the end seat of the vibrating wire strain gauge in the clamping base to prevent sliding;

[0020] Step 4: Adjust the position of the displacement platform to avoid exceeding the strain range of the vibrating wire strain gauge, and adjust the frequency value of the vibrating wire strain gauge to the center frequency;

[0021] Step S5, setting the moving range of the displacement platform, recording the displacement value of the displacement platform and the frequency value of the vibrating-wire strain gauge corresponding to the displacement value, and evaluating the calibration parameters.

[0022] The present invention discloses the following technical effects:

[0023] Compared with the prior art, the present invention has the advantages of large output force value, high displacement accuracy, fast calibration speed, good safety performance, high applicability, etc., and can meet the calibration requirements of vibrating-wire strain gauges of different sizes. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 It is a side view of the automatic calibration device of the vibrating wire strain gauge with force value monitoring function of the present invention;

[0026] Figure 2 It is an axonometric diagram of the automatic calibration device of the vibrating wire strain gauge with force value monitoring function of the present invention;

[0027] Figure 3 It is a structural schematic diagram of a clamping assembly in the calibration device of the present invention;

[0028] In the figure: 1. Base plate; 2. Displacement sensor; 3. Drive assembly; 31. Motor support; 32. Electric cylinder; 33. Servo motor; 4. Moving assembly; 41. Displacement platform; 42. Linear bearing; 43. Tension and pressure sensor; 5. Connecting column; 6. Fixing assembly; 61. First fixing frame; 62. Second fixing frame; 63. Guide shaft; 64. Round cover nut; 7. Clamping assembly; 71. Clamping base; 72. Clamping front knob; 73. Clamping rear knob. DETAILED DESCRIPTION

[0029] 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.

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Embodiment 1:

[0032] Reference Figures 1 to 3 As shown, a first embodiment of the present invention provides an automatic calibration device for a vibrating-wire strain gauge with a force value monitoring function, the device comprising a base plate 1 as the basis of the entire device, the base plate 1 having a horizontal bearing surface, on which a displacement sensor 2, a driving component 3, a moving component 4, a connecting column 5, a fixing component 6 and a clamping component 7 are arranged.

[0033] Specifically, the fixing assembly 6 includes a first fixing frame 61 and a second fixing frame 62 fixedly connected to the bottom plate 1 at intervals. The first fixing frame 61 and the second fixing frame 62 are arranged at intervals along the length direction of the bottom plate 1. In this embodiment, it is assumed that the length direction of the bottom plate 1 is the front-to-back direction and the width direction is the left-to-right direction. The first fixing frame 61 is fixed near one end of the bottom plate 1, and two second fixing frames 62 are provided. The two second fixing frames 62 are respectively fixedly installed on the left and right sides of the middle of the bottom plate 1. A guide shaft 63 is connected between the two second fixing frames 62 and the first fixing frame 61. There are two guide shafts 63. The shaft ends of the two guide shafts 63 are both provided with external threads, and the two ends respectively penetrate the first fixing frame 61 and the second fixing frame 62, and are fixed by a round cover nut 64. Specifically, the second fixing frame 62 is provided with a through hole allowing the guide shaft 63 to pass through, and the diameter of the through hole is equal to the diameter of the shaft end of the guide shaft 63. Correspondingly, two through holes are provided on the first fixing frame 61, and the diameter of the two through holes is also equal to the diameter of the shaft end of the guide shaft 63.

[0034] The moving assembly 4 slides on the two guide shafts 63 along the front-back direction. Specifically, the moving assembly 4 includes a displacement platform 41, a linear bearing 42 and a tension and pressure sensor 43. A through hole is provided on each side of the displacement platform 41. The two through holes are provided on the same horizontal plane. A bearing mounting seat is provided at each end of the through hole. Four linear bearings 42 are provided. The four linear bearings 42 are respectively placed in the displacement platform 41 along the four through holes and fixed on the bearing mounting seats. The guide shaft 63 is passed through the linear bearing 42. The displacement platform 41 can move along the guide shaft 63. A protruding mounting seat is provided at one end of the displacement platform 41. The tension and pressure sensor 43 is fixed on the protruding mounting seat. The tension and pressure sensor 43 monitors the force value applied during the calibration process to avoid exceeding the stress range and damaging the vibrating wire strain gauge being measured.

[0035] The displacement sensor 2 is used to monitor the displacement of the displacement platform 41 in the moving assembly 4. The displacement sensor 2 is fixed on the bottom plate 1, and the probe of the displacement sensor 2 is connected to the moving assembly 4. In some embodiments, the probe of the displacement sensor 2 contacts the inner side of the displacement platform 41 and moves with the displacement platform 41, so that the displacement sensor 2 can monitor the displacement of the displacement platform 41. The displacement sensor 2 is located on the central plane of the displacement platform 41 to prevent the displacement platform 41 from swinging and affecting the displacement measurement accuracy.

[0036] The driving assembly 3 is connected to the moving assembly 4 through the connecting column 5. The driving assembly 3 includes a motor support 31, an electric cylinder 32 and a servo motor 33. The motor support 31 and the electric cylinder 32 are fixed to one end of the bottom plate 1 away from the first fixed frame 61. The servo motor 33 is fixed to the motor support 31, and the output shaft of the servo motor 33 is fixedly connected to the coupling end of the electric cylinder 32. The servo motor 33 has a large output torque. The output shaft of the servo motor 33 rotates to drive the working shaft of the electric cylinder 32 to extend and retract. The end of the working shaft of the electric cylinder 32 is provided with an internal thread for threaded connection with one end of the connecting column 5. The servo motor 33 and the electric cylinder 32 can produce precise displacement, maintain high displacement accuracy, and provide a large pulling and pressing force. The present invention uses the servo motor 33 and the electric cylinder 32 to cooperate to produce displacement, and maintains high displacement accuracy when obtaining a large pulling and pressing force; the working axis of the electric cylinder 32 is coaxial with the force axis of the vibrating wire strain gauge to be measured and is higher than the upper surface of the displacement platform 41, so as to avoid the large torque generated during the calibration process to cause damage to the device structure.

[0037] The connecting column 5 is used to connect the driving component 3 and the moving component 4. One end of the connecting column 5 is connected to the working shaft of the electric cylinder 32 of the driving component 3, and the other end is connected to the tension and pressure sensor 43. Specifically, both ends of the connecting column 5 are provided with external threads, which are respectively threadedly connected to the end of the working shaft of the electric cylinder 32 and the center through hole of the tension and pressure sensor 43.

[0038] The clamping assembly 7 is used to fix the end seat of the vibrating-wire strain gauge to prevent sliding during the calibration process and improve the calibration accuracy. The clamping assembly 7 includes a clamping base 71, a front clamping knob 72 and a rear clamping knob 73. The front clamping knob 72 and the rear clamping knob 73 clamp the end seat of the vibrating-wire strain gauge to be measured in the clamping base 71. The clamping assembly 7 of this embodiment can prevent the vibrating-wire strain gauge to be measured from sliding, improve the calibration accuracy, and can adapt to the end seat thickness of different vibrating-wire strain gauges to be measured, thereby improving the applicability.

[0039] In some optional embodiments of the present invention, the diameters of both ends of the guide shaft 63 are smaller than the diameter of the contact section with the linear bearing 42 , and both ends of the guide shaft 63 are provided with external threads, and the guide shaft 63 can be screwed into the round cover nut 64 through the external threads.

[0040] In some optional embodiments of the present invention, the force axis of the tension and pressure sensor 43 is coaxial with the installation axis of the vibrating-wire strain gauge being measured and is higher than the upper surface of the displacement platform 41 to avoid damage to the device structure caused by large torque generated during calibration.

[0041] In some optional embodiments of the present invention, the tension and pressure sensor 43 is provided with a flange, the tension and pressure sensor 43 is fixed to the displacement platform 41 via the flange, and a through hole with an internal thread is provided at the center of the tension and pressure sensor 43 .

[0042] In some optional embodiments of the present invention, the telescopic working axis of the electric cylinder 32 can drive the displacement platform 41 to move along the guide axis 63, and can apply a large pulling force or pressure to the displacement platform 41 while maintaining a high displacement accuracy of the displacement platform 41. The upper surface of the displacement platform 41 is on the same horizontal plane as the upper surface of the first fixed frame 61.

[0043] In some optional embodiments of the present invention, anti-slip grooves are provided on the inner wall of the clamping base 71 to facilitate better clamping and fixing.

[0044] In some optional embodiments of the present invention, the front wall and the rear wall of the clamping base 71 are both provided with openings with internal threads, and the axes of the two openings coincide with each other. An installation opening is provided on the front wall of the clamping base 71, and the vibrating-wire strain gauge to be measured can be smoothly placed into the clamping base 71 along the installation opening, and the central axis of the vibrating-wire strain gauge coincides with the opening.

[0045] In some optional embodiments of the present invention, the front clamping knob 72 is provided with an external thread, and the front clamping knob 72 is provided with a U-shaped installation opening.

[0046] In some optional embodiments of the present invention, the rear knob 73 is provided with an external thread after clamping, and a blind hole is provided axially at one end of the rear knob 73 provided with the external thread to prevent the end face center of the rear knob 73 from contacting with the end face center of the vibrating-wire strain gauge being measured, thereby damaging the vibrating-wire strain gauge.

[0047] In some optional embodiments of the present invention, the front clamping knob 72 is screwed into the opening on the front wall of the clamping base 71, and the rear clamping knob 73 is screwed into the opening on the rear wall of the clamping base 71. By adjusting the screw-in lengths of the front clamping knob 72 and the rear clamping knob 73, the clamping requirements of the end seats of vibrating-wire strain gauges of different thicknesses can be met. The front clamping knob 72 and the rear clamping knob 73 can clamp the end seat from the front and back sides to prevent the vibrating-wire strain gauge from sliding during the calibration process.

[0048] In some optional embodiments of the present invention, two clamping assemblies 7 form a group, wherein one clamping assembly 7 is fixed on the upper surface of the first fixing frame 61, and the other clamping assembly 7 is fixed on the upper surface of the displacement platform 41, the two clamping assemblies 7 are located on the same axis, and the front walls of the two clamping bases 71 are opposite.

[0049] In some optional embodiments of the present invention, the tension and pressure sensor 43 can monitor in real time the force value applied by the working axis of the electric cylinder 32 on the displacement platform 41, and interrupt the movement of the servo motor 33 when the force value exceeds the set threshold value, so as to avoid damaging the vibrating wire strain gauge being measured due to exceeding the stress range.

[0050] Embodiment 2:

[0051] Embodiment 2 of the present invention further provides a vibrating wire strain gauge automatic calibration method, using the vibrating wire strain gauge automatic calibration device with force value monitoring function described in embodiment 1, the method comprising the following steps:

[0052] Step S1, adjusting the distance between the displacement platform 41 and the first fixing frame 61 according to the gauge length of the vibrating-wire strain gauge to be measured, so that the two end seats of the vibrating-wire strain gauge can be easily placed in the two clamping bases 71 at the same time;

[0053] Step S2, recording the frequency value of the vibrating-wire strain gauge in a relaxed state, and using it as the center frequency value of the vibrating-wire strain gauge;

[0054] Step S3, tighten the front clamping knob 72 and the rear clamping knob 73 to fix the end seat of the vibrating wire strain gauge in the clamping base 71 to prevent the vibrating wire strain gauge from sliding during the calibration process;

[0055] Step 4, in order to avoid exceeding the strain range of the vibrating-wire strain gauge and thus causing damage to the vibrating-wire strain gauge, the position of the displacement platform 41 is adjusted to adjust the frequency value of the vibrating-wire strain gauge to the frequency value of the relaxation state in step S2;

[0056] Step S5, setting the moving range of the displacement platform 41 according to the strain range of the vibrating wire strain gauge, the displacement sensor 2 records the displacement value of the displacement platform 41, and simultaneously records the frequency value of the vibrating wire strain gauge corresponding to the displacement value, and evaluating the required calibration parameters.

[0057] The details not disclosed in the present invention are conventional technical means well known to those skilled in the art.

[0058] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0059] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. An automatic calibration device for a vibrating wire strain gauge with a force value monitoring function, characterized in that: The invention comprises a fixing assembly (6) fixed to a base plate (1), the fixing assembly (6) comprising a first fixing frame (61) and a second fixing frame (62) arranged at intervals along the length direction of the base plate (1), two guide shafts (63) being connected between the first fixing frame (61) and the second fixing frame (62), and a moving assembly (4) sliding linearly back and forth on the two guide shafts (63); at least one pair of mutually cooperating clamping assemblies (7) are mounted facing each other on the moving assembly (4) and the first fixing frame (61) for clamping a vibrating wire strain gauge to be measured; a displacement sensor (2) is connected to a side of the moving assembly (4) facing the first fixing frame (61), and a driving assembly (3) for driving the moving assembly (4) to move closer to or away from the first fixing frame (61) is connected to a side of the moving assembly (4) facing away from the first fixing frame (61).

2. The automatic calibration device for vibrating wire strain gauge with force value monitoring function according to claim 1, characterized in that: The clamping assembly (7) comprises a clamping base (71), a front clamping knob (72) and a rear clamping knob (73), wherein the front clamping knob (72) and the rear clamping knob (73) clamp an end seat of a vibrating-wire strain gauge to be measured within the clamping base (71).

3. The automatic calibration device for vibrating wire strain gauge with force value monitoring function according to claim 2, characterized in that: A pair of mutually matching clamping assemblies (7) are displaced on the same axis, and the front walls of the clamping bases (71) in the two clamping assemblies (7) are opposite to each other.

4. The automatic calibration device for vibrating wire strain gauge with force value monitoring function according to claim 1, characterized in that: The moving assembly (4) comprises a displacement platform (41), a through hole is provided on each side of the displacement platform (41), the two guide shafts (63) pass through the two through holes, a protruding mounting seat is provided at one end of the displacement platform (41), a tension and pressure sensor (43) is fixed on the protruding mounting seat, and the tension and pressure sensor (43) is connected to the driving assembly (3).

5. The automatic calibration device for vibrating wire strain gauge with force value monitoring function according to claim 4, characterized in that: Linear bearings (42) are also provided between the two ends of the through hole and the guide shaft (63).

6. The automatic calibration device for vibrating wire strain gauge with force value monitoring function according to claim 1, characterized in that: The displacement sensor (2) is fixed on the base plate (1), and the probe of the displacement sensor (2) is connected to the moving component (4).

7. The automatic calibration device for vibrating wire strain gauge with force value monitoring function according to claim 6, characterized in that: The displacement sensor (2) is located on the central plane of the displacement platform (41), is in contact with the inner side surface of the displacement platform (41), and moves along with the displacement platform (41).

8. The automatic calibration device for vibrating wire strain gauge with force value monitoring function according to claim 1, characterized in that: The driving assembly (3) comprises a motor support (31), an electric cylinder (32) and a servo motor (33); the motor support (31) and the electric cylinder (32) are fixed to one end of the base plate (1) away from the first fixing frame (61); the servo motor (33) is fixed to the motor support (31); and the output shaft of the servo motor (33) is fixedly connected to one end of the electric cylinder (32).

9. The automatic calibration device for vibrating wire strain gauge with force value monitoring function according to claim 8, characterized in that: One end of the electric cylinder (32) away from the servo motor (33) is connected to a connecting column (5), and both ends of the connecting column (5) are provided with external threads, which are respectively threadedly connected to the shaft end of the electric cylinder (32) and the central through hole of the tension and pressure sensor (43).

10. A vibrating wire strain gauge automatic calibration method, using the vibrating wire strain gauge automatic calibration device with force value monitoring function according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step S1, adjusting the distance between the displacement platform (41) and the first fixing frame (61) to ensure that the end seat of the vibrating wire strain gauge can be placed in the clamping base (71); Step S2, recording the frequency value of the vibrating wire strain gauge in the relaxed state as the center frequency; Step S3, fixing the end seat of the vibrating-wire strain gauge in the clamping base (71) to prevent sliding; Step 4, adjusting the position of the displacement platform (41) to avoid exceeding the strain range of the vibrating wire strain gauge, and adjusting the frequency value of the vibrating wire strain gauge to the center frequency; Step S5: setting the movement range of the displacement platform (41), recording the displacement value of the displacement platform (41) and the frequency value of the vibrating-wire strain gauge corresponding to the displacement value, and evaluating the calibration parameters.

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