Torque generator for small torque calibration

Abstract

The present invention relates to a torque generator for micro torque calibration, comprising a counterweight, a crossbeam, a blade support, a frame, an external magnetic tube, a coil, a coil frame, a trapezoidal magnetic conductor, a magnetic shoe, a permanent magnet, a push blade, a hanging blade, and a torque output shaft, wherein the inverted V-shaped notch of the crossbeam is supported on the blade of the blade support, a counterweight is installed at one end of the crossbeam, and the V-shaped notch at the other end is connected to the push blade and the hanging blade; the axis of the torque output shaft is perpendicular to the crossbeam and passes through the supporting point of the blade support; the permanent magnet, the external magnetic tube, the magnetic shoe, and the trapezoidal magnetic conductor form a moving iron of a voice coil actuator, and the moving iron is fixedly connected to the push blade and the hanging blade, and is balanced by the counterweight through the crossbeam. The present invention adopts voice coil drive technology, and the travel force stability can be achieved in a short voice coil, the adjustable magnetic compensation can generate a uniform magnetic field, and the adaptive ball joint can avoid the deviation caused by posture changes, thereby ensuring the stability and accuracy of micro torque generation.

Description

Technical Field

[0001] The invention relates to a torque generator, in particular to a torque generating device which can be used to generate a small torque for calibration. Background Art

[0002] Dynamic torque measurement is widely used in industrial control systems. During measurement, it is necessary to face interference such as vibration and impact. The torque is dynamically loaded and the torque data is not stable. The research on the measurement of tiny dynamic torque is of great significance in the fields of precision control and aerospace, but there is currently no such dedicated tiny dynamic torque calibration device in China.

[0003] The measurement of tiny dynamic torque generally uses the principle of tiny precision equal arm method, and the calibration test is carried out based on the principle that the output torque of the measured torque sensor (such as gyro motor, torque motor, etc.) is balanced with the standard electromagnetic torque (calibrated by weights) given by the feedback signal of the torque device part of the mechanical system in the standard device. That is, through a certain structural design, the tiny torque signal is balanced with the torque generated by the torque loading system to measure the tiny torque. The core of this principle is the torque loading system. The accuracy, sensitivity, and stability of the dynamic torque loading device determine the performance of the torque measurement device. It is of great significance to design a suitable torque loading device. However, since the torque loading often introduces uncertainty and error through the intermediate torque transmission mechanism, the improvement of measurement accuracy is limited.

[0004] In order to avoid the errors caused by the intermediate transmission link, direct drive technology is often used in high-precision actuators. Electromagnetic torquers characterized by voice coil motors can overcome the above shortcomings. Voice coil motors are actuators that use a powered coil in a permanent magnetic field to generate thrust for direct drive. They have the characteristics of strong direct drive capability, no intermediate transmission link, and good dynamic responsiveness. They are widely used in the field of precision motion control. The voice coil motor is used to drive the end of the cantilever. The cantilever, as a force arm, can generate torque under the action of the driving force. This torque can be used for measurement after being calibrated with weights.

[0005] After searching the literature on the prior art, it was found that regarding the torque generator for micro-torque calibration, the China Aviation Great Wall Metrology Institute has been engaged in micro-torque measurement research for many years. It has proposed an electromagnetic balance and used precision screws for leveling. It has also proposed using the torque of a torque motor during rotation as a torque generating device. The above research work is different from the torque generating device driven by a voice coil in terms of working principle, structural form and performance. Summary of the invention

[0006] The present invention is aimed at the demand for torque generation in micro-torque measurement, and proposes a torque generator based on voice coil drive technology. The short voice coil can achieve stroke force stability, the adjustable magnetic compensation can generate a uniform magnetic field, and the adaptive ball joint can avoid deviations caused by posture changes. The above ensures the stability and accuracy of micro-torque generation.

[0007] To achieve the above-mentioned purpose, the technical solution of the present invention is: an electromagnetic torquer for a small torque generating device, comprising a counterweight, a crossbeam, a blade support, a frame, an external magnetic tube, a coil, a coil frame, a trapezoidal magnetic conductor, a magnetic shoe, a permanent magnet, a push blade, a hanging blade, and a torque output shaft, wherein the inverted V-shaped notch of the crossbeam is supported on the blade of the blade support, a counterweight is installed at one end of the crossbeam, and the V-shaped notch at the other end is connected to the push blade and the hanging blade; the axis of the torque output shaft is perpendicular to the crossbeam and passes through the support point of the blade support; the permanent magnet, the external magnetic tube, the magnetic shoe, and the trapezoidal magnetic conductor form a moving iron of a voice coil actuator, and the moving iron is fixedly connected to the push blade and the hanging blade, and is balanced by the counterweight through the crossbeam.

[0008] Furthermore, the coil is wound on a coil frame, and the coil frame is fixed to the frame. In the initial position, the coil is located in the middle of the air gap working magnetic field when no power is supplied.

[0009] Furthermore, the magnetic shoe is cylindrical, the inner side height is smaller than the outer side height, and its cross section is trapezoidal. The magnetic lines of force are vertically emitted to the working magnetic field of the air gap, which has a convergence effect on the magnetic lines of force, can reduce leakage magnetic field, and ensure the stability of the magnetic field.

[0010] Furthermore, the outer side surface of the trapezoidal magnetic conductor is designed to be trapezoidal, forming a small angle θ with the axis, which is a part of the cone and can change the thickness of the air gap, so that the magnetic resistance of the magnetic circuit of each magnetic line of force is the same, ensuring the uniformity of the working magnetic field in the air gap.

[0011] Furthermore, when the coil is not energized, the counterweight is located at a position at one end of the beam away from the knife edge support, so that the beam remains horizontal and balanced and stationary.

[0012] Furthermore, when the coil is energized and the moving iron is subjected to an upward or downward electromagnetic force, the torque output shaft transmits torque and changes the direction of the torque by changing the direction of the current in the coil.

[0013] Furthermore, when the moving iron is subjected to a downward electromagnetic pulling force, the lifting blade acts in the V-shaped notch of the crossbeam, and the pushing blade does not contact the crossbeam.

[0014] Furthermore, when the moving iron is subjected to an upward electromagnetic thrust, the pushing blade acts in the inverted V-shaped notch of the crossbeam, and the lifting blade does not contact the crossbeam.

[0015] Furthermore, when the moving iron moves upward or downward, the moving iron rotates around the contact point of the lifting blade or the pushing blade under the action of gravity and electromagnetic force to keep the moving iron in a vertical state.

[0016] Furthermore, the magnetic circuit in the magnetic field of the moving iron passes through the permanent magnet, the outer magnetic tube, the magnetic shoe, crosses the air gap, reaches the trapezoidal magnetic conductor, and finally returns to the permanent magnet to close. The magnetic field formed in the air gap is the working magnetic field.

[0017] The beneficial effects of the present invention are:

[0018] The electromagnetic torquer for micro torque calibration of the present invention can solve the problem of micro torque generation in dynamic torque measurement system. In the process of torque generation, the force of the torquer plays a key role. The decisive factors of force include magnetic field, current and coil length in the dynamic process. Among them, magnetic field is the key factor, which is subject to many interference factors, which seriously affects the accuracy and stability of calibration.

[0019] The present invention adopts double blades to adaptively adjust the deflection of the moving iron. When the beam deflects, the moving iron can automatically maintain a vertical state, avoiding mechanical interference between the moving iron deflection and the coil, and maintaining the direction of the magnetic field in the air gap unchanged.

[0020] The present invention adopts a trapezoidal magnetic conductor to correct the magnetic circuit. The trapezoidal magnetic conductor makes the magnetic lines of force evenly distributed, compensates for the magnetic resistance loss, and creates a uniform air gap working magnetic field.

[0021] The present invention adopts magnetic shoes to introduce magnetic lines of force into the air gap, and the magnetic lines of force vertically pass through the short sides, which plays a role of magnetic convergence and prevents the generation of magnetic leakage.

[0022] The above ensures that the coil output force is not affected by the magnetic field but is only related to the current, reducing the nonlinear interference factors of the control, which can improve the accuracy of the output torque and meet the needs of micro torque measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic structural diagram of the torque generator of the present invention;

[0024] Figure 2 It is a schematic diagram of the principle of magnetic field homogenization of the torque generator of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0026] like Figure 1 , 2As shown, the torquer for micro torque calibration of the present invention includes a weight block 1, a crossbeam 2, a blade support 3, a frame 4, an external magnetic tube 5, a coil 6, a coil frame 7, a trapezoidal magnetic conductor 8, a magnetic shoe 9, a permanent magnet 10, a blade pusher 11, a blade lifting edge 12, and a torque output shaft 13.

[0027] The inverted V-shaped notch of the crossbeam 2 is supported on the blade of the blade support 3. The counterweight 1 is installed at one end of the crossbeam 2, and the V-shaped notch at the other end is connected to the push blade 11 and the hanging blade 12. The push blade 11 is connected to the outer magnetic tube 5, the lower part of the outer magnetic tube 5 is placed on the coil frame 7, and magnetic shoes 9 are provided on the inner sides of the lower part of the outer magnetic tube 5. The coil 6 is wound on both sides of the upper part of the coil frame 7. The magnetic shoes 9 correspond to the coil 6. The coil frame 7 has a trapezoidal magnetic conductor 8 built in. The upper part of the trapezoidal magnetic conductor 8 is connected to the outer magnetic tube 5 through a permanent magnet 10. The permanent magnet 10, the outer magnetic tube 5, the magnetic shoes 9, and the trapezoidal magnetic conductor 8 form the moving iron of the voice coil actuator. The moving iron is fixedly connected to the push blade 11 and the hanging blade 12, and is balanced by the counterweight 1 through the crossbeam 2. The coil 6 is wound on a coil frame 7, and the coil frame 7 is fixed to the frame. In the initial position, the coil 6 is located in the middle of the air gap working magnetic field when no power is supplied.

[0028] When the coil 6 is not energized, the position of the counterweight 1 at one end of the beam 2 and the distance from the blade support 3 is adjusted to keep the beam horizontal and balanced. When the coil 6 is energized, when the moving iron is subjected to the electromagnetic upward or downward electromagnetic force, the torque output shaft 13 transmits the torque. By changing the current direction of the coil 6, the direction of the torque can be changed. The axis of the torque output shaft 13 is perpendicular to the beam and passes through the support point of the blade support 3. When the moving iron is subjected to the downward electromagnetic pulling force, the lifting blade 12 acts on the V-shaped notch of the beam 2, and the pushing blade 11 does not contact the beam. When the moving iron is subjected to the upward electromagnetic thrust, the pushing blade 11 acts on the inverted V-shaped notch of the beam 2, and the lifting blade does not contact the beam 2. When the moving iron moves upward or downward, the moving iron rotates around the contact point of the lifting blade 12 or the pushing blade 11 under the action of its gravity and electromagnetic force to keep the moving iron in a vertical state.

[0029] The magnetic field of the moving iron is Figure 2 As shown, the magnetic circuit passes through the permanent magnet 10, the outer magnetic tube 5, the magnetic shoe 9, and reaches the trapezoidal magnetic conductor 8 after crossing the air gap, and finally returns to the permanent magnet 10 to close. The magnetic field formed in the air gap is the working magnetic field. Under normal circumstances, the longer the magnetic circuit in the outer magnetic tube 5 and the trapezoidal magnetic conductor 8, the greater the magnetic resistance, and the sparser the magnetic lines of force will be, thus forming an unevenness from top to bottom in the working magnetic field. In order to compensate for this magnetic resistance loss and ensure the uniformity of the working magnetic field, the outer side surface of the trapezoidal magnetic conductor 8 is designed to be a trapezoid, forming a small angle θ with the axis, changing the thickness of the air gap to increase the magnetic resistance, so that the magnetic circuit magnetic resistance of each magnetic line of force is the same. The magnetic shoe 9 is cylindrical, the height of the inner side surface is smaller than the height of the outer side surface, and its interface is a trapezoid.

[0030] The electromagnetic force of the torquer for the above-mentioned micro-torque calibration forms the moving iron of the voice coil actuator through the permanent magnet 10, the outer magnetic tube 5, the magnetic shoe 9, and the trapezoidal magnetic conductor 8, which is fixed to the frame 4 through the coil 6 and the coil frame 7. When power is turned on, thrust or pulling force is generated between the coil 6 and the moving iron.

[0031] The torque balancing device of the torquer for micro-torque calibration is a lever mechanism, wherein the crossbeam 2 is supported on the blade support 3 of the frame 4, one end of which adopts a counterweight block 1 with an adjustable lever arm, and the other end is connected to the moving iron through a double blade, namely a lifting blade 12 and a pushing blade 11.

[0032] In the torque generating device of the torque generator for micro-torque calibration, when the coil 6 is energized and the moving iron is subjected to an upward or downward electromagnetic force, the torque output shaft 13 transmits the torque to an external device that needs to be calibrated.

[0033] The uniformity and stability of the working magnetic field of the above-mentioned torque converter for micro torque calibration are ensured by the following measures:

[0034] (1) When the crossbeam 2 is unbalanced, the moving iron moves upward or downward. Under the action of its gravity and electromagnetic force, the moving iron rotates around the contact point of the lifting blade 12 or the pushing blade 11, automatically maintaining the vertical state of the moving iron, thereby ensuring that the direction of the working magnetic field where the coil 3 is located does not change, and also avoiding the possible mechanical interference between the moving iron tilt and the coil 3;

[0035] (2) The magnetic shoe 9 is cylindrical, the height of the inner side is smaller than that of the outer side, and its cross section is trapezoidal. The magnetic lines of force are vertically projected into the working magnetic field of the air gap, which has a convergence effect on the magnetic lines of force, reduces leakage magnetic field, and ensures the stability of the magnetic field;

[0036] (3) The outer side surface of the trapezoidal magnetizer 8 is designed to be trapezoidal, forming a small angle θ with the axis, which is a part of the cone, changing the thickness of the air gap. The magnetic resistance increases where the air gap becomes thinner, so that the magnetic resistance of the magnetic circuit of each magnetic line of force is the same, ensuring the uniformity of the working magnetic field in the air gap.

Claims

1. A torque generator for micro torque calibration, comprising a counterweight, a crossbeam, a knife edge support, a frame, an outer magnetic tube, a coil, a coil frame, a trapezoidal magnetic conductor, a magnetic shoe, a permanent magnet, a knife edge pusher, a knife edge lifting, and a torque output shaft, characterized in that: The inverted V-shaped notch of the crossbeam is supported on the blade supported by the knife edge, a counterweight is installed at one end of the crossbeam, and the V-shaped notch at the other end is connected to the push knife edge and the hanging knife edge; the push knife edge is connected to the outer magnetic conductive cylinder, the lower part of the outer magnetic conductive cylinder is placed on the coil frame, magnetic shoes are provided on the two inner sides of the lower part of the outer magnetic conductive cylinder, coils are wound on both sides of the upper part of the coil frame, the magnetic shoes correspond to the coils, a trapezoidal magnetic conductor is built into the coil frame, and the upper part of the trapezoidal magnetic conductor is connected to the outer magnetic conductive cylinder through a permanent magnet; the moving iron is connected to the push knife edge and the hanging knife edge. The blade mouth is fixedly connected, passed through the crossbeam, and balanced by the counterweight; the axis of the torque output shaft is perpendicular to the crossbeam and passes through the support point supported by the blade edge; the permanent magnet, the outer magnetic tube, the magnetic shoe, and the trapezoidal magnetic conductor form the moving iron of the voice coil actuator, and the moving iron is fixedly connected to the push blade mouth and the lifting blade mouth, and balanced by the counterweight through the crossbeam; the coil is wound on the coil frame, the coil frame is fixed to the frame, and in the initial position, the coil is located in the middle position of the air gap working magnetic field when no power is supplied.

2. The torque generator for micro torque calibration according to claim 1, characterized in that: The magnetic shoe is cylindrical, with the inner side height being smaller than the outer side height, and its cross section being trapezoidal. The magnetic lines of force are vertically emitted to the working magnetic field of the air gap, which has a convergence effect on the magnetic lines of force, can reduce leakage magnetic field, and ensure the stability of the magnetic field.

3. The torque generator for micro torque calibration according to claim 1, characterized in that: The outer side surface of the trapezoidal magnetic conductor is designed to be trapezoidal, forming a small angle θ with the axis, which is a part of the cone and can change the thickness of the air gap, so that the magnetic resistance of the magnetic circuit of each magnetic line of force is the same, ensuring the uniformity of the working magnetic field in the air gap.

4. The torque generator for micro torque calibration according to claim 1, characterized in that: When the coil is not energized, the counterweight is located at a position at one end of the beam away from the knife edge support, so that the beam remains horizontal and balanced.

5. The torque generator for micro torque calibration according to claim 1, characterized in that: When the coil is energized, the moving iron is subjected to an upward or downward electromagnetic force, and the torque output shaft transmits torque, and the direction of the torque is changed by changing the direction of the current in the coil.

6. The torque generator for micro torque calibration according to claim 1, characterized in that: When the moving iron is subjected to a downward electromagnetic pulling force, the lifting knife edge acts in the V-shaped notch of the crossbeam, and the pushing knife edge does not contact the crossbeam.

7. The torque generator for micro torque calibration according to claim 1, characterized in that: When the moving iron is subjected to an upward electromagnetic thrust, the pushing blade acts in the inverted V-shaped notch of the crossbeam, and the lifting blade does not contact the crossbeam.

8. The torque generator for micro torque calibration according to claim 1, characterized in that: When the moving iron moves upward or downward, the moving iron rotates around the contact point of the lifting blade or the pushing blade under the action of gravity and electromagnetic force to keep the moving iron in a vertical state.

9. The torque generator for micro torque calibration according to claim 1, characterized in that: The magnetic circuit in the magnetic field of the moving iron passes through the permanent magnet, the outer magnetic tube, the magnetic shoe, passes through the air gap, reaches the trapezoidal magnetic conductor, and finally returns to the permanent magnet to close. The magnetic field formed in the air gap is the working magnetic field.

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