Arm Ratio Adjustment System and Method for Lever-Amplified Torque Standard Device

Abstract

This invention relates to an arm ratio adjustment system and method for a lever-amplified torque standard device, belonging to the field of torque measurement technology. The system includes an electromagnetic force measuring system and an arm ratio fine-tuning structure; the arm ratio fine-tuning structure is used to fine-tune the arm length; the electromagnetic force measuring system is used to measure the unbalanced torque introduced by the arm length difference, in order to calculate the arm length difference after fine-tuning. This invention effectively solves the problems of arm length adjustment and measurement in lever-amplified torque standard devices, thereby obtaining a standard torque value.

Description

Technical Field

[0001] This invention belongs to the field of torque measurement technology and relates to an arm ratio adjustment system and method for a lever amplification torque standard device. Background Technology

[0002] The lever-amplified torque standard device uses the principle of static weight balance loading, such as... Figure 1 As shown, a standard weight is loaded onto a flexible suspension at one end of the lever arm. The downward force generated by the weight is obtained based on its mass and the local gravitational acceleration. Multiplying this force by the lever arm length yields the standard torque value. This standard torque value is transmitted to the torque sensor or torque measuring instrument being calibrated via the central output shaft of the standard device, thus outputting the standard torque value. In practice, the lever arm of the lever amplification torque standard device has two directions, left and right, as shown... Figure 1 As shown.

[0003] M + M - Let the forward and reverse torque values ​​of the lever-amplified torque standard device be represented, then:

[0004] M + =m1×L1

[0005] M - =m2×L2

[0006] m1 represents the mass of the weight loaded on the left pan, with the left arm length being L1 and the right arm length being L2; m2 represents the mass of the weight loaded on the left pan. The implementation of the lever fulcrum in a lever-type torque standard device is a crucial step. Common lever fulcrums generally include the knife-bearing type and the spring-loaded type. The knife-bearing type lever fulcrum has a simple structure, is easy to assemble and adjust, and has low processing costs, but it suffers from poor realignment. That is, when the balance tilts during operation, the lever fulcrum is prone to displacement, causing a change in the lever arm length. Therefore, the arm length should be checked periodically for correction. The checking process requires in-situ measurement to avoid the impact of differences in arm length before and after disassembly. Measuring the arm length of the knife-bearing fulcrum lever using traditional geometric methods is impractical. Another structure uses a spring-loaded flexible suspension structure as the fulcrum of the lever system. The spring-loaded structure is as follows... Figure 2 As shown. A schematic diagram of the torque standard device for the spring-loaded flexible suspension lever system is shown below. Figure 3 .

[0007] The spring-type flexible suspension structure effectively solves the problem of poor lever fulcrum repositioning. However, the sensitive part of the spring is located inside the spring, and it is impossible to reach the sensitive point through traditional contact measurement methods. In other words, the position of the lever fulcrum cannot be directly measured, which leads to the inaccurate measurement of the lever arms L1 and L2, and the inability to effectively trace the standard torque value. Summary of the Invention

[0008] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose an arm ratio adjustment system and method for a lever amplification torque standard device, which can effectively solve the problems of arm length adjustment and arm length measurement of the lever amplification torque standard device, and thus obtain the standard torque value.

[0009] The solution of the present invention is:

[0010] An arm ratio adjustment system for a lever amplification torque standard device includes an electromagnetic force measuring system and an arm ratio fine-tuning structure; the arm ratio fine-tuning structure is used to fine-tune the arm length; the electromagnetic force measuring system is used to measure the unbalanced torque introduced by the arm length difference to calculate the arm length difference after fine-tuning.

[0011] Preferably, the arm ratio fine-tuning structure includes a left angle wedge, a left fine-tuning screw, a middle angle wedge, a balance beam, a right fine-tuning screw, and a right angle wedge; the lower surface of the balance beam is machined with a groove, and the left angle wedge, middle angle wedge, and right angle wedge are all located in the groove; the middle angle wedge is fixed to the base by a suspension spring, and the middle angle wedge has an isosceles trapezoidal structure, located between the left angle wedge and the right angle wedge. The left angle wedge and the right angle wedge have the same structure. The structure is a right-angled trapezoid. The inclined surfaces of the left and right angle wedges are in contact with the two inclined surfaces of the middle angle wedge, and the left and right angle wedges are symmetrical about the center of the middle angle wedge. The left angle wedge is connected to the balance beam by the left fine-adjustment screw, and the right angle wedge is connected to the balance beam by the right fine-adjustment screw. The vertical surface of the left angle wedge is parallel to and close to the left vertical surface of the groove of the balance beam, and the vertical surface of the right angle wedge is parallel to and close to the right vertical surface of the groove of the balance beam.

[0012] Preferably, the inclination angle of the left-angle wedge, right-angle wedge, and middle-angle wedge is 80°.

[0013] Preferably, for every 1° rotation of the left fine-adjustment screw, the left angle wedge block is displaced 0.00278mm in the vertical direction relative to the balance beam; for every 1° rotation of the right fine-adjustment screw, the right angle wedge block is displaced 0.00278mm in the vertical direction relative to the balance beam.

[0014] Preferably, the electromagnetic force measurement system includes a torque converter, a damper, a displacement sensor, a torque processing unit, a velocity signal amplifier, a velocity converter, a displacement converter, and an amplification unit. The torque converter is fixed at one end of the balance beam, and the damping coil and the displacement sensor are located at the other end of the balance beam. The displacement sensor is used to sense changes in the angular displacement of the balance beam, and its output value is converted by the displacement converter and then output to the amplification unit. The damper provides damping for the system, and its output damping force is converted into a velocity signal by the velocity converter, amplified by the velocity signal amplifier, and then output to the amplification unit. The PID processing unit processes the signal amplified by the amplification unit to obtain a feedback current, which is fed back to the torque converter to generate a balancing force. The feedback current reflects the magnitude of the unbalanced torque.

[0015] Preferably, the arm length difference can be calculated from the unbalanced torque.

[0016] A method for adjusting the arm ratio of a lever-amplified torque standard device includes:

[0017] 1) Based on actual usage conditions, define the left arm length as L1 and the right arm length as L2;

[0018] 2) With the left and right weight pans unloaded, calculate the output voltage V1 based on the feedback current of the electromagnetic force measuring system;

[0019] 3) Load a weight of mass m1 onto the left pan and a weight of the same specification onto the right pan, denoted as m2. Calculate the output voltage V2 of the electromagnetic force measuring system. During the test, the output voltage and torque of the electromagnetic force measuring system have a linear relationship, and their ratio is the sensitivity of the electromagnetic force measuring system, denoted as A. Therefore:

[0020] m1gL1-m2gL2=(V2-V1)A (1)

[0021] 4) Swap the weights on the left and right pans and measure again. Load a weight of mass m2 onto the left pan and a weight of mass m1 onto the right pan. Calculate the output voltage V3 based on the feedback current of the electromagnetic force measuring system. The change in the voltage output of the electromagnetic force measuring system is directly caused by the unequal arms, resulting in:

[0022] m2gL1-m1gL2=(V3-V1)A (2)

[0023] 5) Remove the weights loaded on the left and right pans, then load other weights of E1 grade on the left pan, denoted as m3. Calculate the output voltage V4 based on the feedback current of the electromagnetic force measuring system. Compared to the unloaded state, the change in the voltage output value of the electromagnetic force measuring system is directly caused by the weight of mass m3, resulting in:

[0024] m3gL1=(V4-V1)A (3)

[0025] 6) After the balance beam is machined, its total length is measured using a coordinate measuring machine and denoted as L. Then:

[0026] L1 + L2 = L (4)

[0027] By combining equations (1) to (4), the specific values ​​of the lengths of the two arms can be calculated:

[0028]

[0029] Adjust the arm ratio fine-tuning structure according to the specific difference in arm length on both sides until the arm length is completely divided equally.

[0030] The preferred method for adjusting the arm ratio fine-tuning structure is as follows:

[0031] When you need to fine-tune the balance beam to the left, first loosen the right fine-tuning screw, then adjust the left fine-tuning screw to press the left angle wedge and move it upward along the inclined surface of the middle angle wedge, thereby squeezing the balance beam and forcing it to shift to the left. At this time, the left arm becomes longer and the right arm becomes shorter. After adjusting the arm length to the appropriate position, tighten the right fine-tuning screw to lock the right angle wedge, thus completing the fine-tuning of the balance arm length to the left.

[0032] When you need to fine-tune the balance beam to the right, first loosen the left fine-tuning screw, then adjust the right fine-tuning screw to press the right angle wedge and move it upward along the inclined surface of the middle angle wedge, thereby squeezing the balance beam and forcing it to shift to the right. At this time, the right arm becomes longer and the left arm becomes shorter. After adjusting the arm length to the appropriate position, tighten the left fine-tuning screw to lock the left angle wedge, thus completing the fine-tuning of the balance arm length to the right.

[0033] The advantages of this invention compared to the prior art are:

[0034] (1) The present invention uses the angle wedges on the left and right sides in conjunction with the adjusting screws to convert the vertical displacement of the angle wedges into the horizontal displacement of the balance beam by using the inclined plane, and subdivides the displacement to achieve micron-level arm length fine adjustment.

[0035] (2) The present invention designs an electromagnetic force measurement system that can convert the unbalanced torque of a lever into a voltage signal and builds an automatic measurement system with a negative feedback circuit, which can realize the measurement of the unbalanced torque of the lever.

[0036] (3) This invention designs a calculation method that utilizes the unbalanced torque generated by the standard weights and the difference in length between the left and right arms to be equivalent to the voltage signal output by the electromagnetic force measuring system. By exchanging the weights on the left and right pans, the error introduced by the unequal amount of the standard weights is eliminated, and the ratio of the lengths of the left and right arms is calculated. By measuring the total length of the lever arms using geometric means, the specific values ​​of the lengths of the left and right arms can be obtained. Combined with the arm ratio adjustment structure, micron-level quantitative and fine-tuning of the lever arm length can be achieved. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the working principle of a lever-amplified torque standard device.

[0038] Figure 2 This is a structural diagram of a suspension spring;

[0039] Figure 3 This is a torque standard device employing a spring-type flexible suspension structure;

[0040] Figure 4 Schematic diagram of the left and right angle wedges;

[0041] Figure 5 This is a schematic diagram of a mid-angle wedge block;

[0042] Figure 6 and Figure 7 For arm ratio fine-tuning structure;

[0043] Figure 8 Schematic diagram of an electromagnetic force measurement system that converts unbalanced torque into a voltage signal;

[0044] Figure 9 This is a schematic diagram of the left and right weight pans without load.

[0045] Figure 10 This is a schematic diagram showing the loading of the left and right weight pans;

[0046] Figure 11 This is a diagram illustrating the swapping of the left and right weights;

[0047] Figure 12 This is a schematic diagram of the left weight plate being loaded. Detailed Implementation

[0048] The invention will now be further described with reference to the accompanying drawings.

[0049] This invention achieves fine-tuning of arm length by designing an arm ratio fine-tuning structure; it also designs an electromagnetic force measurement system with negative feedback circuitry to measure the unbalanced torque introduced by the arm length difference; and it designs an arm length measurement method to achieve accurate arm length measurement.

[0050] (1) Arm ratio fine-tuning structure

[0051] Design a fine-tuning structure for arm ratio, such as Figure 6-7 As shown. The suspension spring is the fulcrum of the balance beam. One end of the mid-angle wedge block 3 is connected to the base 9 through the suspension spring 8, and the other end is connected to the balance beam 4 through the connecting screw 5, thereby achieving the purpose of fixing the balance beam 4 to the base 9 through the suspension spring 8.

[0052] Specifically, the lower surface of the balance beam 4 is machined with a groove, and the left angle wedge 1, the middle angle wedge 3, and the right angle wedge 7 are all located in the groove. The middle angle wedge 3 is fixed to the base 9 by a suspension spring 8. The middle angle wedge 3 is an isosceles trapezoidal structure and is located between the left angle wedge 1 and the right angle wedge 7. The left angle wedge 1 and the right angle wedge 7 have the same structure, both being right-angled trapezoidal structures. The inclined surfaces of the left angle wedge and the right angle wedge are in contact with the inclined surfaces on both sides of the middle angle wedge, and the left angle wedge 1 and the right angle wedge 7 are symmetrical about the center of the middle angle wedge 3. The left angle wedge 1 is connected to the balance beam 4 by a left fine-tuning screw 2, and the right angle wedge 7 is connected to the balance beam 4 by a right fine-tuning screw 6. The vertical surface of the left angle wedge is parallel to and closely attached to the left vertical surface of the groove of the balance beam, and the vertical surface of the right angle wedge is parallel to and closely attached to the right vertical surface of the groove of the balance beam. Figure 7 11 is the torque output shaft.

[0053] The vertical freedom of the balance beam is constrained, but there is a gap in the threaded hole of the connecting screw. The beam can be moved horizontally by adjusting the angle wedge, thereby causing the beam to move relative to the suspension spring in the horizontal direction, achieving the purpose of fine-tuning the arm length.

[0054] When it is necessary to finely adjust the balance beam to the left, first loosen the right fine-adjustment screw 6, then adjust the left fine-adjustment screw 2, pressing the left angle wedge 1 so that it moves upward along the inclined surface of the middle angle wedge 3, thereby squeezing the balance beam and forcing it to shift to the left. At this time, the left arm becomes longer and the right arm becomes shorter. After adjusting the arm length to the appropriate position, tighten the right fine-adjustment screw 6 and lock the right angle wedge 7 to complete the fine adjustment of the balance arm length to the left.

[0055] When it is necessary to finely adjust the balance beam to the right, first loosen the left fine-adjustment screw 2, then adjust the right fine-adjustment screw 6 to press the right angle wedge 7 so that it moves upward along the inclined surface of the middle angle wedge 3, thereby squeezing the balance beam and forcing it to shift to the right. At this time, the right arm becomes longer and the left arm becomes shorter. After adjusting the arm length to the appropriate position, tighten the left fine-adjustment screw 2 to lock the left angle wedge 1, completing the fine-tuning of the balance arm length to the right.

[0056] The left, right, and middle angle wedges are designed with an inclination angle of 80°. The left and right fine-tuning screws are designed with M6×1 threads. For every 1° rotation of the screw, the angle wedges are displaced 0.00278 mm vertically relative to the balance beam. This translates to a horizontal displacement of 0.0005 mm relative to the lever origin (suspending spring). This allows for micron-level arm length fine-tuning.

[0057] See the structural diagrams of the left and right angle wedges. Figure 4 See the diagram of the mid-angle wedge block structure. Figure 5 .

[0058] (2) Electromagnetic force measurement system - to realize the quantification of unbalanced torque

[0059] In addition to the need for fine-tuning the arm length, quantitative measurement of the adjustment length is also required for the fine-tuning mechanism to have practical value. The change in arm length is reflected in the lever system as torque. Therefore, this invention relates to an electromagnetic force measurement system that converts lever imbalance torque into a voltage signal. By adding an automatic measurement system with negative feedback circuitry, the automatic measurement of lever imbalance torque can be achieved. Figure 8 This is a schematic diagram of an automatic measurement system. A torque converter is fixed to one end of the balance beam, while a damping coil and a displacement sensor are located at the other end. The principle is that when the lever is subjected to an unbalanced torque, it tilts to one side. The displacement sensor senses changes in the angular displacement of the balance beam, and its output value is converted by a displacement converter and then sent to the amplification unit. The damper provides damping for the system, and its output damping force is converted into a velocity signal by a velocity converter, amplified by a velocity signal amplifier, and then sent to the amplification unit. The PID processing unit processes the amplified signal to obtain a feedback current, which is fed back to the torque converter to generate a balancing force. This feedback current reflects the magnitude of the unbalanced torque. Through this system, the unbalanced torque present in the lever system can be converted into a voltage signal.

[0060] (3) Method for Precise Equal Division Measurement of Arm Length

[0061] Building upon the ability to finely adjust the arm length and quantify the unbalanced torque, a calculation method is needed to establish a relationship between the quantified torque value and the arm length in order to ultimately achieve precise equal division of the arm length. The method is as follows:

[0062] 1) Based on actual usage conditions, define the left arm length as L1 and the right arm length as L2;

[0063] 2) With the left and right weight pans 10 unloaded, calculate the output voltage V1 based on the feedback current of the electromagnetic force measuring system. Figure 9 As shown;

[0064] 3) Load a weight of mass m1 onto the left pan and a weight of the same specification onto the right pan. Considering that the two weights are not exactly the same mass, let's denote their mass as m2. Calculate the output voltage V2 based on the feedback current of the electromagnetic force measuring system. The change in the voltage output of the electromagnetic force measuring system is directly caused by the unequal arms. For example... Figure 10 As shown, during the test, the voltage output and torque of the electromagnetic force measuring system have a linear relationship, and their ratio is the sensitivity of the electromagnetic force measuring system, denoted as A (Nm / V). Therefore:

[0065] m1gL1-m2gL2=(V2-V1)A (1)

[0066] in:

[0067] m1: Equal weights loaded on the left pan, in kg;

[0068] m2: Equal weights loaded on the right pan, in kg;

[0069] g: acceleration due to gravity, m / s² 2 ;

[0070] L1: Length of left arm, in meters;

[0071] L2: Right arm length, in meters;

[0072] V2: Output voltage of the electromagnetic force measuring system, in V;

[0073] A: Sensitivity of the small torque sensor, Nm / V.

[0074] 4) To eliminate the influence of unequal weights on the left and right pans, the weights on the left and right pans were swapped and the measurement was repeated. A weight of mass m2 was loaded on the left pan and a weight of mass m1 was loaded on the right pan. The output voltage of the electromagnetic force measuring system was read as V3. The change in the voltage output of the electromagnetic force measuring system is directly caused by the unequal arms. Figure 11 As shown. We can obtain:

[0075] m2gL1-m1gL2=(V3-V1)A (2)

[0076] in:

[0077] V3: Output voltage of the electromagnetic force measurement system, V.

[0078] 5) Remove the weights loaded on the left and right pans, then load an E1 grade weight of other specifications onto the left pan, denoted as m3. Read the voltage output of the electromagnetic force measuring system as V4. Compared to the unloaded state, the change in the voltage output value of the electromagnetic force measuring system is directly caused by the weight of mass m3. Figure 12 As shown, we can obtain:

[0079] m3gL1=(V4-V1)A (3)

[0080] in:

[0081] m3: Another weight of a certain size loaded on the left pan, in kg;

[0082] V4: Output voltage of the electromagnetic force measurement system, in volts (V).

[0083] 6) The total length of the lever arm can be easily measured using geometric methods. After the lever beam is machined, its total length is measured using a coordinate measuring machine and denoted as L. Then:

[0084] L1 + L2 = L (4)

[0085] By combining equations (1) to (4), the specific values ​​of the lengths of the two arms can be calculated:

[0086]

[0087] Based on the difference in the specific values ​​of the arm lengths on both sides, adjust the arm ratio fine-tuning structure mentioned in (1) until the arm lengths are completely divided equally.

[0088] This invention is mainly used to adjust the arm length ratio of a torque standard device, thereby providing an accurate torque standard value.

Claims

1. A lever-amplified torque standard device arm ratio adjustment system, characterized in that: Including an electromagnetic force measurement system and an arm ratio fine-tuning structure; The arm length adjustment structure is used to fine-tune the arm length; The electromagnetic force measurement system is used to measure the unbalanced torque introduced by the arm length difference, so as to calculate the arm length difference after arm length fine-tuning; The arm ratio fine-tuning structure includes a left angle wedge (1), a left fine-tuning screw (2), a middle angle wedge (3), a balance beam (4), a right fine-tuning screw (6), and a right angle wedge (7); the lower surface of the balance beam (4) is machined with a groove, and the left angle wedge (1), the middle angle wedge (3), and the right angle wedge (7) are all located in the groove; the middle angle wedge (3) is fixed to the base (9) by a suspension spring (8), and the middle angle wedge (3) is an isosceles trapezoidal structure. The middle angle wedge (3) is located between the left angle wedge (1) and the right angle wedge (7). The wedges (7) have the same structure, both being right-angled trapezoidal structures. The inclined surfaces of the left and right angle wedges are in contact with the inclined surfaces on both sides of the middle angle wedge. The left and right angle wedges (1) and the middle angle wedge (7) are symmetrical about the center of the middle angle wedge (3). The left angle wedge (1) is connected to the balance beam (4) by the left fine-tuning screw (2), and the right angle wedge (7) is connected to the balance beam (4) by the right fine-tuning screw (6). The vertical surface of the left angle wedge is parallel to and close to the left vertical surface of the groove of the balance beam, and the vertical surface of the right angle wedge is parallel to and close to the right vertical surface of the groove of the balance beam.

2. The arm ratio adjustment system for a lever-amplified torque standard device according to claim 1, characterized in that: The inclined planes of the left-angle wedge, right-angle wedge, and middle-angle wedge have an inclination angle of 80°.

3. The arm ratio adjustment system for a lever-amplified torque standard device according to claim 1, characterized in that: The electromagnetic force measurement system includes a torque converter, a damper, a displacement sensor, a torque processing unit, a velocity signal amplifier, a velocity converter, a displacement converter, and an amplification unit. The torque converter is fixed at one end of the balance beam, while the damping coil and the displacement sensor are located at the other end. The displacement sensor is used to sense changes in the angular displacement of the balance beam, and its output value is converted by the displacement converter and then output to the amplification unit. The damper provides damping for the system, and its output damping force is converted into a velocity signal by the velocity converter, amplified by the velocity signal amplifier, and then output to the amplification unit. The PID processing unit processes the signal amplified by the amplification unit to obtain a feedback current, which is fed back to the torque converter to generate a balancing force. The feedback current reflects the magnitude of the unbalanced torque.

4. The arm ratio adjustment system for a lever-amplified torque standard device according to claim 3, characterized in that: The arm length difference can be calculated from the unbalanced torque.

5. A method for adjusting the arm ratio of a lever-amplified torque standard device, characterized in that, The arm ratio adjustment system for a lever-amplified torque standard device as described in claim 1 is implemented, comprising: 1) Based on actual usage conditions, define the left arm length as L1 and the right arm length as L2; 2) With the left and right weight pans unloaded, calculate the output voltage V1 based on the feedback current of the electromagnetic force measuring system; 3) Load a weight of mass m1 onto the left pan and a weight of the same specification onto the right pan, denoted as m2. Calculate the output voltage V2 of the electromagnetic force measuring system. During the test, the output voltage and torque of the electromagnetic force measuring system have a linear relationship, and their ratio is the sensitivity of the electromagnetic force measuring system, denoted as A. Therefore: m1gL1-m2gL2=(V2-V1)A (1) 4) Swap the weights on the left and right pans and measure again. Load a weight of mass m2 onto the left pan and a weight of mass m1 onto the right pan. Calculate the output voltage V3 based on the feedback current of the electromagnetic force measuring system. The change in the voltage output of the electromagnetic force measuring system is directly caused by the unequal arms, resulting in: m2gL1-m1gL2=(V3-V1)A (2) 5) Remove the weights loaded on the left and right pans, then load other weights of E1 grade on the left pan, denoted as m3. Calculate the output voltage V4 based on the feedback current of the electromagnetic force measuring system. Compared to the unloaded state, the change in the voltage output value of the electromagnetic force measuring system is directly caused by the weight of mass m3, resulting in: m3gL1=(V4-V1)A (3) 6) After the balance beam is machined, its total length is measured using a coordinate measuring machine and denoted as L. Then: L1 + L2 = L (4) By combining equations (1) to (4), the specific values ​​of the lengths of the two arms can be calculated: Adjust the arm ratio fine-tuning structure according to the specific difference in arm length on both sides until the arm length is completely divided equally.

6. The method for adjusting the arm ratio of a lever-amplified torque standard device according to claim 5, characterized in that, The method for adjusting the arm ratio and fine-tuning the structure is as follows: When you need to fine-tune the balance beam to the left, first loosen the right fine-tuning screw, then adjust the left fine-tuning screw to press the left angle wedge and move it upward along the inclined surface of the middle angle wedge, thereby squeezing the balance beam and forcing it to shift to the left. At this time, the left arm becomes longer and the right arm becomes shorter. After adjusting the arm length to the appropriate position, tighten the right fine-tuning screw to lock the right angle wedge, thus completing the fine-tuning of the balance arm length to the left. When you need to fine-tune the balance beam to the right, first loosen the left fine-tuning screw, then adjust the right fine-tuning screw to press the right angle wedge and move it upward along the inclined surface of the middle angle wedge, thereby squeezing the balance beam and forcing it to shift to the right. At this time, the right arm becomes longer and the left arm becomes shorter. After adjusting the arm length to the appropriate position, tighten the left fine-tuning screw to lock the left angle wedge, thus completing the fine-tuning of the balance arm length to the right.

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