A method and system for measuring the torque of a brushless torque motor

Abstract

The present invention relates to the technical field of measurement methods, and discloses a torque measurement method and system for a brushless torque motor. In this method, the rotor is installed on the rotating shaft, and then the stator is installed on the base. A dynamometer is used to apply tensile forces in the positive and negative directions along the plumb line until the rotating shaft rotates. The stator is then disassembled, and the dynamometer is used to apply a tensile force until the rotating shaft rotates. According to the principle of torque balance, the mechanical equilibrium equations at different rotation instants are respectively listed, so as to calculate the excitation torque and the eccentric force torque respectively. The present invention directly uses the drive shaft system structure for measurement, simplifies the measurement device, greatly reduces the processing difficulty and processing cost, can reliably obtain the excitation torque and the eccentric force torque, has a simple calculation process, improves the measurement accuracy, and is also convenient for operation and observation.

Description

Technical Field

[0001] The present invention relates to the technical field of torque measurement, and more specifically, to a torque measurement method and system for a brushless torque motor. Background Art

[0002] After the permanent magnet of the split brushless torque motor is excited, an exciting torque is generated, which has a great influence on the torque ripple and starting voltage of the split brushless torque motor and is an important index for the inspection of the split brushless torque motor. There are mainly two existing public methods for measuring the exciting torque. One is to directly measure the force by hanging weights and then multiply it by the force arm to calculate the torque. The other is to multiply the starting current by the torque sensitivity to calculate the exciting torque.

[0003] Both of the above two methods require a dedicated rotation shaft system to be built, and the stator and rotor of the split brushless torque motor are respectively installed on the stator and rotor of the shaft system. The structure is complex, and the processing and assembly requirements are high. Both methods ignore the frictional torque of the bearings and the eccentric torque of the shaft system in the rotation shaft system, and the measurement results have large errors and low accuracy. At the same time, the first method requires multiple operations of adding and subtracting weights, which is cumbersome. The second method also requires the split brushless torque motor to be energized and kept in a stalled state during measurement, measure the stall torque and stall current, and then calculate the torque sensitivity. And affected by the maximum stall time of the split brushless torque motor, the measurement time of the exciting torque must be strictly limited and not exceed the maximum stall time of the split brushless torque motor. Special power supplies and measuring instruments need to be additionally configured, with large investment and high cost.

[0004] In addition, in the drive shaft system adopted by the split brushless torque motor, the load, the rotating shaft, and the rotor of the brushless torque motor can rotate. However, due to the influence of processing accuracy, spatial dimensions, weight limitations, etc., generally, the centers of mass of the load, the rotating shaft, and the rotor of the motor do not coincide with the center of rotation of the rotating shaft. It is necessary to measure and control the eccentric torque of the drive shaft system after assembly, and perform structural balancing if necessary according to the measurement results. There are mainly two existing public methods for measuring the eccentric torque of the drive shaft system. One is to separately measure the mass and center of mass of the rotating part of the drive shaft system, directly calculate the gravity, and then multiply it by the gravity arm to calculate the eccentric torque. The other is to use the piezoelectric effect principle of strain gauges, paste strain gauges on the measured part, and measure the torque through a single-chip full-bridge or group-bridge method of the strain gauges to process the circuit.

[0005] Among the above, the first method requires measurement before the drive shaft system is assembled, or after the assembled drive shaft system is disassembled. Moreover, a special quality characteristic measuring instrument is needed for the measurement. When measuring, the rotating part of the drive shaft system needs to be installed on the moving shaft of the quality characteristic measuring instrument to perform high-speed rotation. The structure is complex, the investment is large, and the cost is high. The formal assembly of the drive shaft system can only be carried out after the measurement, and the eccentric error caused by the installation error cannot be avoided. The principle of the second method is complex and the operation is cumbersome. Strain gauges need to be pasted on the measured part, and the requirements for pasting the strain gauges are very high. Inappropriate pasting will cause problems such as zero drift and creep. After the strain gauges are pasted, it is also necessary to check for bubbles, warping, and degumming, and measure for short circuits, open circuits, and resistance mutations. Summary of the Invention

[0006] The object of the present invention is to provide a torque measurement method and system for a brushless torque motor, which can reliably obtain the excitation torque and the eccentric torque, the calculation process is simple, and the measurement accuracy is improved, aiming at the technical problems existing in the prior art.

[0007] In order to solve the above-mentioned problems, the technical solution adopted by the present invention is as follows:

[0008] The present invention provides a torque measurement method for a brushless torque motor. The specific steps of the measurement method are as follows:

[0009] Construct a drive shaft system and install a brushless torque motor. The drive shaft system includes a base and a rotating shaft. The rotating shaft is arranged on the base and is perpendicular to the plumb line. The rotating shaft is connected to a load. The motor includes a stator and a rotor. The rotor is sleeved on the rotating shaft, and the stator is arranged on the base and is located on the outer surface of the rotor.

[0010] One end of a pulling rope is pasted on the outer end face of the rotor, and the other end of the pulling rope is connected to the hook of a dynamometer. The distance between the bonding point of the pulling rope and the center line of the rotating shaft is L1.

[0011] Slowly apply a pulling force along the plumb line direction from zero to the dynamometer until the rotor just starts to rotate relative to the stator, and record the reading of the dynamometer at this time as F1.

[0012] Rotate the rotating shaft again to make the rotor return to the initial position, and slowly apply a pulling force along the opposite direction of the plumb line from zero to the dynamometer until the rotor just starts to rotate relative to the stator, and record the reading of the dynamometer at this time as F2.

[0013] According to the obtained forces F1 and F2, calculate that the eccentric torque of the drive shaft system of the brushless torque motor is 0.5×(F1 - F2)×L1.

[0014] Remove the stator of the motor, rotate the rotating shaft again to make the rotor return to the initial position;

[0015] Apply a pulling force slowly along the plumb line direction starting from zero with a dynamometer until the rotor just starts to rotate relative to the base, and record the reading of the dynamometer at this time as F3;

[0016] Based on the obtained force F1 and force F3, calculate the excitation torque of the brushless torque motor as (F1 - F3) × L1.

[0017] Furthermore, at the initial position, alignment marking lines are provided on the outer end faces of the stator and the rotor, and on the base.

[0018] Furthermore, calculating the eccentric moment of the drive shaft system of the brushless torque motor specifically includes:

[0019] Based on F1, the mechanical equilibrium equation at the moment when the rotor just starts to rotate relative to the stator is as follows:

[0020] F1 × L1 - G × L - M1 - M2 = 0 (1)

[0021] Based on F2, the mechanical equilibrium equation at the moment when the rotor just starts to rotate relative to the stator is as follows:

[0022] F2 × L1 + G × L - M1 - M2 = 0 (2)

[0023] Wherein, G is the gravity of the combined body of the rotating shaft, the load, and the rotor, L is the gravity arm of the combined body, M1 is the frictional torque of the bearings in the drive shaft system, and M2 is the excitation torque of the brushless torque motor;

[0024] Based on formula (1) and formula (2), calculate the eccentric moment of the drive shaft system of the brushless torque motor as: G × L = 0.5 × (F1 - F2) × L1.

[0025] Furthermore, calculating the excitation torque of the brushless torque motor specifically includes:

[0026] Based on the F3, the mechanical equilibrium equation at the moment when the rotor just starts to rotate relative to the base is as follows:

[0027] F3 × L1 - G × L - M1 = 0 (3)

[0028] Based on formula (1) and formula (3), calculate the excitation torque of the brushless torque motor as: M2 = (F1 - F3) × L1.

[0029] Furthermore, the dynamometer adopts an electronic dynamometer, and the increment of the pulling force applied each time is the minimum unit reading value of the dynamometer.

[0030] The present invention provides a torque measurement system for a brushless torque motor, and this measurement system includes:

[0031] Shafting construction module: used to construct a drive shafting and install a brushless torque motor. The drive shafting includes a base and a rotating shaft. The rotating shaft is arranged on the base and perpendicular to the plumb line. The rotating shaft is connected to a load. The motor includes a rotor sleeved on the rotating shaft and a stator arranged on the base and located on the outer surface of the rotor.

[0032] Force measurement installation module: used to paste one end of a pulling rope on the outer end face of the rotor. The other end of the pulling rope is connected to the hook of a dynamometer. The distance between the bonding point of the pulling rope and the center line of the rotating shaft is L1.

[0033] First operation module: used to slowly apply a pulling force along the plumb line direction from zero to the dynamometer until the rotor just starts to rotate relative to the stator, and record the reading of the dynamometer at this time as F1.

[0034] Second operation module: used to rotate the rotating shaft again to make the rotor return to the initial position, and slowly apply a pulling force along the opposite direction of the plumb line from zero to the dynamometer until the rotor just starts to rotate relative to the stator, and record the reading of the dynamometer at this time as F2.

[0035] Eccentric moment calculation module: used to calculate the eccentric moment of the drive shafting of the brushless torque motor as 0.5×(F1 - F2)×L1 according to the obtained forces F1 and F2.

[0036] Furthermore, the measurement system further includes:

[0037] Disassembly module: used to remove the stator of the motor and rotate the rotating shaft again to make the rotor return to the initial position.

[0038] Third operation module: used to slowly apply a pulling force along the plumb line direction from zero to the dynamometer until the rotor just starts to rotate relative to the base, and record the reading of the dynamometer at this time as F3.

[0039] Excitation torque calculation module: used to calculate the excitation torque of the brushless torque motor as (F1 - F3)×L1 according to the obtained forces F1 and F3.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0041] (1) The measurement method of the present invention makes full use of the existing drive shafting structure, without the need to specially build a measurement rotating shafting, simplifies the measurement device, and greatly reduces the processing difficulty and processing cost. Considering the friction torque of the bearings in the drive shafting, through three force measurements, under the coupling action of the friction torque of the bearings, the eccentric moment of the shafting and the excitation torque of the motor, the measurement of the excitation torque of the motor is realized, and at the same time, the on-line measurement and discrimination of the eccentric moment during the assembly process of the drive shafting are realized. The calculation process is simple and the measurement accuracy is improved.

[0042] (2) In the present invention, alignment marking lines are respectively provided on the outer end faces of the stator and the rotor, and on the base, which facilitates observing the moment when the rotor rotates relative to the stator and the base, ensuring that the readings of the dynamometer obtained are accurate and reliable.

[0043] (3) By measuring the force three times and applying the principle of moment balance, the present invention realizes the measurement of the exciting torque of the motor and the eccentric moment of the drive shaft system without measuring the frictional torque of the bearing, which is simple, reliable and easy to implement.

[0044] (4) The present invention uses an electronic dynamometer to measure the force, without the need to add or subtract weights, nor strain gauges and processing circuits. The operation and observation are simple and convenient, and the measurement is also reliable.

[0045] (5) The measurement system of the present invention directly uses the drive shaft system for measurement. The rotor is installed on the rotating shaft and then the stator is installed on the base. The dynamometer is used to apply tensile forces in the positive and negative directions along the plumb line until the rotating shaft rotates. Then the stator is disassembled and the dynamometer is used to apply tensile force until the rotating shaft rotates. According to the principle of moment balance, the mechanical equilibrium equations at different moments of rotation are respectively listed, so as to obtain the exciting torque and the eccentric moment respectively. The measurement accuracy is high, the calculation process is simple, and it is also convenient for operation and observation. Description of the Drawings

[0046] In order to more clearly illustrate the solutions in the present invention, the following will give a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings. Among them:

[0047] Figure 1 is the flowchart of the torque measurement method for the brushless torque motor of the present invention.

[0048] Figure 2 is the schematic diagram of the first measurement in the state of the drive shaft system of the present invention and when the motor stator and rotor are installed.

[0049] Figure 3 is the schematic diagram of the second measurement of the present invention.

[0050] Figure 4 is the schematic diagram of the measurement in the state of the drive shaft system of the present invention and when only the motor rotor is installed.

[0051] Figure 5 is the schematic diagram of the principle of the torque measurement system for the brushless torque motor of the present invention.

[0052] Among them, 1 - base, 2 - rotating shaft, 3 - stator, 4 - rotor, 5 - centroid of the combination of the rotating shaft, load and rotor, 6 - center line of the rotating shaft, 7 - pull rope, 8 - bonding point of the pull rope, 9 - dynamometer. Specific implementation mode

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this invention belongs; the terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For example, the terms "length", "width", "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or position based on the orientation or position shown in the drawings, and are only for convenience of description and cannot be construed as a limitation to the technical solution of the present invention.

[0054] The terms "comprising" and "having" and any variations thereof in the specification and claims of the present invention and the above drawings are intended to cover non - exclusive inclusion; the terms "first", "second", etc. in the specification and claims of the present invention or the above drawings are used to distinguish different objects and not to describe a specific order. In the specification, claims and the above drawings of the present invention, when an element is referred to as "fixed to" or "mounted on" or "disposed on" or "connected to" another element, it can be directly or indirectly located on that other element. For example, when an element is referred to as "connected to" another element, it can be directly or indirectly connected to that other element.

[0055] In addition, the mention of "embodiment" herein means that a specific feature, structure or characteristic described in connection with the embodiment can be included in at least one embodiment of the present invention. The phrase appears at various positions in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0056] Refer to Figure 1 As shown, the present invention provides a torque measurement method for a brushless torque motor. The specific steps of the measurement method are as follows:

[0057] Step S1: As Figure 2 shown, construct a drive shaft system and install a brushless torque motor. The drive shaft system includes a base 1 and a rotating shaft 2. The rotating shaft 2 is arranged on the base 1 and is perpendicular to the plumb line. The rotating shaft 2 is connected to a load. The motor includes a stator 3 and a rotor 4. The rotor 4 is sleeved on the rotating shaft 2. The stator 3 is arranged on the base 1 and is located outside the outer surface of the rotor 4.

[0058] Specifically, the rotating shaft 2 is connected to the base 1 through a bearing to ensure reliable connection. The rotating shaft 2, the rotor 4 and the load can perform rotary motion.

[0059] Step S2: One end of a pulling rope 7 is pasted on the outer end face of the rotor 2, and the other end of the pulling rope 7 is connected to the hook of a dynamometer 9; the distance between the bonding point 8 of the pulling rope on the rotor 2 and the center line 6 of the rotating shaft is L1.

[0060] Step S3: Slowly apply a pulling force to the dynamometer 9 starting from zero along the plumb line direction (i.e., vertically upward in the figure) until the rotor 4 just starts to rotate relative to the stator 3, and record the reading of the dynamometer 9 at this time, denoted as F1.

[0061] In this step, alignment marking lines are provided on the outer end faces of the stator 3 and the rotor 4. During the process of applying the pulling force, observe the marking lines on the outer end faces of the rotor 4 and the stator 3. When the alignment marking lines of the two just become misaligned, it is determined that the rotor 4 just starts to rotate relative to the stator 3. At this time, the reading of the corresponding dynamometer 9 is F1, which is convenient for observing the moment of rotation of the rotor 4.

[0062] Step S4: As shown in the figure, rotate the rotating shaft 2 again to make the rotor 4 return to the initial position, and slowly apply a pulling force to the dynamometer 9 starting from zero along the opposite direction of step S3 (i.e., vertically downward in the figure) until the rotor 4 of the motor just starts to rotate relative to the stator 3, and record the reading of the dynamometer 9 at this time, denoted as F2. Figure 3 In this step, rotate the rotating shaft 2 to make the marking line on the outer end face of the rotor 4 return to the position in step S3. During the process of applying the pulling force, also observe the marking lines on the outer end faces of the rotor 4 and the stator 3 of the motor to determine that the rotor 4 just starts to rotate relative to the stator 3.

[0063] In this step, rotate the rotating shaft 2 to make the marking line on the outer end face of the rotor 4 return to the position in step S3. During the process of applying the pulling force, also observe the marking lines on the outer end faces of the rotor 4 and the stator 3 of the motor to determine that the rotor 4 just starts to rotate relative to the stator 3.

[0064] Step S5: According to the obtained forces F1 and F2, calculate the eccentric moment of the drive shaft system of the brushless torque motor to be 0.5×(F1 - F2)×L1.

[0065] In this step S5, calculating the eccentric moment of the drive shaft system of the brushless torque motor specifically includes:

[0066] Based on the principle of moment balance, according to F1, the mechanical balance equation at the moment when the rotor 4 of the motor just starts to rotate relative to the stator 3 is as follows:

[0067] F1×L1 - G×L - M1 - M2 = 0 (1)

[0068] Similarly, based on the principle of moment balance, according to F2, the mechanical balance equation at the moment when the rotor 4 of the motor just starts to rotate relative to the stator 3 is as follows:

[0069] F2×L1 + G×L - M1 - M2 = 0 (2)

[0070] Wherein, G is the gravity of the combined body of the rotating shaft 2, the load, and the rotor 4, L is the moment arm of the gravity of the combined body of the rotating shaft 2, the load, and the rotor 4, M1 is the frictional torque of the bearings in the drive shaft system, and M2 is the excitation torque of the split brushless torque motor;

[0071] According to formula (1) and formula (2), the eccentric moment of the brushless torque motor drive shaft system is calculated as:

[0072] G×L = 0.5×(F1 - F2)×L1.

[0073] Step S6: As Figure 4 shown, remove the stator 3 of the motor, rotate the rotating shaft 2 again to make the rotor 4 return to the initial position, that is, the marking line on the outer end face of the rotor 4 returns to the position in step S2.

[0074] Step S7: Slowly apply a pulling force vertically along the plumb line direction (i.e., vertically upward in the figure) from zero with the dynamometer 9. During the process of applying the pulling force, observe the outer end face of the rotor 4 and the base 1 until the rotor 4 just starts to rotate relative to the base 1, and record the reading of the dynamometer 9 at this time, denoted as F3.

[0075] Specifically, the base 1 is also provided with alignment marking lines corresponding to the position of the rotor 4. In the initial position, the alignment marking lines of the two are aligned. When the alignment marking lines of the two are just misaligned, it means that the rotor 4 just starts to rotate relative to the base 1, which is convenient for observation.

[0076] Step S8: According to the obtained force F1 and force F3, calculate the excitation torque of the brushless torque motor as (F1 - F3)×L1.

[0077] In this step S8, calculating the excitation torque of the brushless torque motor specifically includes:

[0078] Based on the principle of torque balance, according to the F3, the mechanical equilibrium equation when the rotor 4 of the motor just starts to rotate relative to the base 1 is as follows:

[0079] F3×L1 - G×L - M1 = 0 (3)

[0080] According to formula (1) and formula (3), calculate the excitation torque of the brushless torque motor as: M2 = (F1 - F3)×L1.

[0081] Furthermore, the dynamometer 9 adopts an electronic dynamometer, and the increment value of the pulling force applied each time is the minimum unit reading value of the dynamometer, which can avoid inaccurate measurement results caused by excessive force application and improve the measurement accuracy.

[0082] Refer to Figure 5 As shown, the present invention also provides a torque measurement system for a brushless torque motor, including:

[0083] Shafting construction module: used to construct a drive shafting and install a brushless torque motor; specifically, the drive shafting includes a base 1 and a rotating shaft 2, the rotating shaft 2 is arranged on the base 1 and is perpendicular to the plumb line, and the rotating shaft 2 is connected to a load; the motor 1 includes a stator 3 and a rotor 4, the rotor 4 is sleeved on the rotating shaft 2, and the stator 3 is arranged on the base 1 and is located outside the outer surface of the rotor 4.

[0084] Force measurement installation module: used to paste one end of a pull rope 7 on the outer end face of the rotor, the other end of the pull rope 7 is connected to the hook of a dynamometer 9, and the distance between the pull rope bonding point and the center line of the rotating shaft is L1.

[0085] First operation module: used to slowly apply a pulling force to the dynamometer 9 along the plumb line direction starting from zero until the rotor 4 just rotates relative to the stator 3, and record the reading of the dynamometer 9 at this time as F1.

[0086] Second operation module: used to re-rotate the rotating shaft 2 to make the rotor 4 return to the initial position, and slowly apply a pulling force to the dynamometer 9 along the opposite direction of the plumb line starting from zero until the rotor 4 of the motor just rotates relative to the stator 3, and record the reading of the dynamometer 9 at this time as F2.

[0087] Eccentric torque calculation module: used to calculate the eccentric torque of the drive shafting of the brushless torque motor as 0.5×(F1 - F2)×L1 according to the obtained force F1 and force F2.

[0088] Disassembly module: used to remove the stator 3 of the motor, re-rotate the rotating shaft 2 to make the rotor 4 return to the initial position.

[0089] Third operation module: used to slowly apply a pulling force to the dynamometer 9 along the plumb line direction starting from zero until the rotor 4 just rotates relative to the base 1, and record the reading of the dynamometer 9 at this time as F3.

[0090] Excitation torque calculation module: used to calculate the excitation torque of the brushless torque motor as (F1 - F3)×L1 according to the obtained force F1 and force F3.

[0091] Specifically, the system provided by the embodiments of the present invention is specifically used to execute the above method embodiments, and the embodiments of the present invention will not be elaborated herein.

[0092] The torque measurement method and system for the brushless torque motor provided by the present invention make full use of the existing drive shaft system structure, without disassembling the drive shaft system. When measuring, the drive shaft system has been formally assembled, effectively avoiding the eccentric error caused by the installation error, and considering the frictional torque of the bearings in the drive shaft system. By applying the torque balance principle, while not measuring the frictional torque of the bearings, the measurement of the exciting torque of the motor and the eccentric torque of the drive shaft system is realized, which is simple, reliable and easy to implement. In addition, when measuring the exciting torque, the present invention does not require the split brushless torque motor to be powered on and blocked, the measurement time is not limited by the maximum blocking time, no additional dedicated power supply and measuring instrument are required, and the debugging method is simple and practical.

[0093] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A method for measuring the torque of a brushless torque motor, characterized in that: The specific steps of this measurement method are as follows: Construct a drive shaft system and install a brushless torque motor. The drive shaft system includes a base and a rotating shaft. The rotating shaft is arranged on the base and is perpendicular to the plumb line. The rotating shaft is connected to a load. The motor includes a stator and a rotor. The rotor is sleeved on the rotating shaft, and the stator is arranged on the base and is located on the outer surface of the rotor. One end of a pulling rope is pasted on the outer end face of the rotor, and the other end of the pulling rope is connected to the hook of a dynamometer. The distance between the bonding point of the pulling rope and the center line of the rotating shaft is L1. Slowly apply a pulling force along the plumb line direction from zero to the dynamometer until the rotor just starts to rotate relative to the stator, and record the reading of the dynamometer at this time as F1. Rotate the rotating shaft again to make the rotor return to the initial position, and slowly apply a pulling force along the opposite direction of the plumb line from zero to the dynamometer until the rotor just starts to rotate relative to the stator, and record the reading of the dynamometer at this time as F2. According to the obtained forces F1 and F2, calculate the eccentric moment of the drive shaft system of the brushless torque motor as 0.5×(F1 - F2)×L1. Remove the stator of the motor, rotate the rotating shaft again to make the rotor return to the initial position. Slowly apply a pulling force along the plumb line direction from zero to the dynamometer until the rotor just starts to rotate relative to the base, and record the reading of the dynamometer at this time as F3. According to the obtained forces F1 and F3, calculate the excitation torque of the brushless torque motor as (F1 - F3)×L1.

2. The method for measuring the torque of a brushless torque motor according to claim 1, characterized in that: At the initial position, alignment marking lines are set on the outer end faces of the stator and the rotor, and on the base.

3. The method for measuring the torque of a brushless torque motor according to claim 1 or 2, characterized in that: The calculation of the eccentric moment of the drive shaft system of the brushless torque motor specifically includes: According to F1, the mechanical equilibrium equation at the moment when the rotor just starts to rotate relative to the stator is as follows: F1×L1 - G×L - M1 - M2 = 0 (1) According to F2, the mechanical equilibrium equation at the moment when the rotor just starts to rotate relative to the stator is as follows: F2×L1 + G×L - M1 - M2 = 0 (2) Wherein, G is the gravity of the combined body of the rotating shaft, the load, and the rotor, L is the gravity arm of the combined body, M1 is the frictional torque of the bearing in the drive shaft system, and M2 is the excitation torque of the brushless torque motor. According to formula (1) and formula (2), calculate the eccentric moment of the drive shaft system of the brushless torque motor as: G×L = 0.5×(F1 - F2)×L1.

4. The method for measuring the torque of a brushless torque motor according to claim 3, characterized in that: The calculation of the excitation torque of the brushless torque motor specifically includes: According to F3, the mechanical equilibrium equation at the moment when the rotor just starts to rotate relative to the base is as follows: F3×L1 - G×L - M1 = 0 (3) According to formula (1) and formula (3), calculate the excitation torque of the brushless torque motor as: M2 = (F1 - F3)×L1.

5. The method for measuring the torque of a brushless torque motor according to claim 1 or 4, characterized in that: The dynamometer adopts an electronic dynamometer, and the increment of the pulling force applied each time is the minimum unit reading value of the dynamometer.

6. A system based on the method for measuring the torque of a brushless torque motor according to any one of claims 1 to 5, characterized in that: This measurement system includes: Shafting construction module: used for constructing a driving shafting and installing a brushless torque motor. The driving shafting includes a base and a rotating shaft. The rotating shaft is arranged on the base and perpendicular to the plumb line, and the rotating shaft is connected to a load. The motor includes a rotor sleeved on the rotating shaft and a stator arranged on the base and located on the outer surface of the rotor. Force measurement installation module: used for pasting one end of a pull rope on the outer end face of the rotor. The other end of the pull rope is connected to the hook of a dynamometer. The distance between the bonding point of the pull rope and the center line of the rotating shaft is L1. First operation module: used for slowly applying a pulling force along the plumb line direction from zero to the dynamometer until the rotor just rotates relative to the stator, and recording the reading of the dynamometer at this time as F1. Second operation module: used for rotating the rotating shaft again to make the rotor return to the initial position, and slowly applying a pulling force along the opposite direction of the plumb line from zero to the dynamometer until the rotor just rotates relative to the stator, and recording the reading of the dynamometer at this time as F2. Eccentric moment calculation module: used for calculating the eccentric moment of the driving shafting of the brushless torque motor as 0.5×(F1 - F2)×L1 according to the obtained force F1 and force F2. The measurement system further includes: Disassembly module: used for disassembling the stator of the motor, rotating the rotating shaft again to make the rotor return to the initial position. Third operation module: used for slowly applying a pulling force along the plumb line direction from zero to the dynamometer until the rotor just rotates relative to the base, and recording the reading of the dynamometer at this time as F3. Excitation torque calculation module: used for calculating the excitation torque of the brushless torque motor as (F1 - F3)×L1 according to the obtained force F1 and force F3.

Images