Device and method for testing output torque of single-phase single-beat stepping motor

Abstract

The invention discloses a single-phase single-beat stepping motor output torque testing device and method. The testing device comprises a torque sensor, a large gear, a torque wheel, a thin wire, a large spring, a small spring, a spring frame, an angle encoder, an interface connecting piece, an industrial personal computer and a tested motor fixing tool. The torque wheel and the spring in the testing device are replaceable parts and can be replaced according to the torque range of the tested motor so as to adapt to different motor testing requirements, motor driving power-up and torque testing in the testing device are controlled by software, and the testing device can be used for testing the output torque of other stepping motors by modifying the software.

Description

Technical Field

[0001] The present application relates to the field of motor torque testing, and in particular to a single-phase single-beat stepper motor output torque testing device and method. Background Art

[0002] At present, the output torque test of single-phase single-beat stepper motor in the prior art adopts the method of hanging weights. A tool with a diameter of 10mm is installed on the motor output shaft, and a nylon line is passed around the tool, and the weights are hung below. The motor is powered by a pulse generator, so that the motor rotates 3 times without losing steps. The maximum output torque of the motor can be driven by multiplying the maximum weight mass by the radius of the tool. Due to the influence of inertia and the electromagnetic torque fluctuation of the motor during continuous rotation, the hanging weight will swing and vibrate, and the test stability is not good. Therefore, the continuous rotation of the motor was later changed to manual single-step rotation. After the swing and vibration of the hanging weight basically stopped or stabilized by hand, the next step was taken to improve the test stability.

[0003] According to the working principle of the motor, during the power-on period, the motor generates a large electromagnetic torque, which drives the motor rotor to rotate rapidly and the attached weight to move rapidly. Then, during the power-off period, the weight continues to move upward under the action of inertia, and the motor drives the rotor to rotate through the mechanical torque of the spring. At this time, the load is close to zero, and the motor rotates rapidly to the next starting position. Therefore, the motor output torque measured by this method is not the real output torque of the motor. When different types of thin wires are used to hang the weights, the movement speed of the weights is different during the power-on period due to the different elasticity of the thin wires. After the pulse power is off, the inertia of the weights has different effects on the motor output torque. When the length of the thin wire hanging the weights is different, the inertia of the weights has different effects on the motor output torque. For example, when testing the output torque of the same motor, the same method is used, and the test results of different thin wires hanging weights can differ by more than 50%. Using the method of hanging weights, the test resolution is ±1gf*5mm, approximately 0.049mNm. The test resolution is low, and the entire test process requires a lot of manual operation, resulting in low test efficiency. Summary of the invention

[0004] In view of this, an object of the present invention is to provide a single-phase single-beat stepper motor output torque testing device and method.

[0005] The present invention provides a single-phase single-beat stepper motor output torque test device, which is characterized in that the test device comprises: a torque sensor, a large gear, a torque wheel, a thin wire, a large spring, a small spring, a spring frame, an angle encoder, an interface connector, an industrial computer and a fixed tooling for the motor to be tested;

[0006] The large gear is set to mesh with the output shaft gear of the motor under test, and the output shaft gear of the motor under test meshes with the internal gear installed on the shaft of the angle encoder. The large gear is connected to the input shaft of the torque sensor, and the torque sensor output shaft is equipped with a torque wheel. When the output shaft of the motor under test rotates, the large gear will be driven to rotate. The rotational inertia of the large gear simulates the rotational inertia of the motor under actual working conditions. When the large gear rotates, it drives the torque wheel to rotate. The torque wheel is connected to one end of the small spring set in the spring frame through a thin wire, and the other end of the small spring is connected to the inner end of the spring frame. The outer side of the end of the spring frame connected to the small spring is connected to one end of the large spring, and the other end of the large spring is fixed. When the torque wheel rotates, it stretches the spring through the thin wire to apply a load to the motor under test. When the torque wheel stretches the spring through the thin wire, the small spring deforms first. When the small spring reaches the maximum displacement, that is, one end of the small spring contacts the spring frame, the large spring begins to deform. When the output shaft of the motor under test rotates, it also drives the angle encoder shaft to rotate, which is used to test the rotation angle of the motor.

[0007] Furthermore, the testing device also includes a motor driving circuit, and the motor driving circuit is provided with an H-bridge driving circuit.

[0008] Furthermore, the industrial computer controls the motor under test via an H-bridge driving circuit, and the industrial computer is connected to an angle encoder and a torque sensor.

[0009] Furthermore, the torque wheel radius is 5 mm.

[0010] In addition, the present invention also provides a testing method based on the above-mentioned single-phase single-beat stepper motor output torque testing device, which is characterized by comprising the following steps:

[0011] S1, the industrial computer powers on the motor under test step by step according to the power-on time, so that the motor under test rotates;

[0012] S2, during the rotation of the motor under test, a load is applied to the motor under test through the torque wheel, thin wire, large spring and small spring;

[0013] S3, after the industrial computer powers on the motor under test each time, it reads the torque value of the torque sensor and the rotation angle value of the angle encoder at the same time;

[0014] S4, when the rotation angle value of the angle encoder is less than the threshold angle after power-on once, the power-on is stopped, and the torque value of the torque sensor read after the last power-on is set to be the maximum output capacity of the motor under test.

[0015] Furthermore, the threshold angle is 90°.

[0016] Beneficial effects of the present invention:

[0017] (1) The torque wheel and spring in the test device of the present invention are replaceable parts, which can be replaced according to the torque range of the motor to be tested to meet different motor testing requirements. (2) The motor drive power-on and test torque in the test device of the present invention are software controlled, and can be used for output torque testing of other stepper motors by modifying the software. (3) The test device of the present application can be tested in high temperature, low temperature and vibration environments, while other test devices in the prior art can only work in normal conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the output torque test device of the single-phase single-beat stepping motor of the present invention;

[0019] Figure 2 It is a schematic diagram of the motor driving circuit of the single-phase single-beat stepping motor output torque testing device of the present invention;

[0020] In the figure, 1. torque sensor, 2. large gear, 3. torque wheel, 4. thin wire, 5. large spring, 6. small spring, 7. spring frame, 8. angle encoder, 9. interface connector, 10. motor under test. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0022] Example 1

[0023] The present invention provides a single-phase single-beat stepper motor output torque test device, characterized in that the test device comprises: a torque sensor 1, a large gear 2, a torque wheel 3, a thin wire 4, a large spring 5, a small spring 6, a spring frame 7, an angle encoder 8, an interface connector 9, an industrial computer and a fixed tooling of a motor to be tested 10;

[0024] The large gear 2 is configured to mesh with the output shaft gear of the motor 10 under test, and the output shaft gear of the motor 10 under test meshes with the internal gear installed on the shaft of the angle encoder 8. The large gear 2 is connected to the input shaft of the torque sensor 1, and the torque sensor 1 output shaft is equipped with a torque wheel 3. When the output shaft of the motor 10 under test rotates, the large gear is driven to rotate. The rotational inertia of the large gear simulates the rotational inertia of the motor under actual working conditions. When the output shaft of the motor 10 under test rotates, the angle encoder shaft is also driven to rotate. The torque wheel 3 is connected to one end of a small spring 6 set in a spring frame 7 through a thin wire 4, and the other end of the small spring 6 is connected to the inner end of the spring frame 7. The outer side of the end of the spring frame 7 connected to the small spring 6 is connected to one end of a large spring 5, and the other end of the large spring 5 is fixed. The test device is as follows: Figure 1 shown.

[0025] Furthermore, the test device also includes a motor drive circuit, and the motor drive circuit is provided with an H-bridge drive circuit. Figure 2 shown.

[0026] Furthermore, the industrial computer controls the motor 10 under test via an H-bridge driving circuit, and the industrial computer is connected to the angle encoder 8 and the torque sensor 1 .

[0027] Furthermore, the radius of the torque wheel 3 is 5 mm.

[0028] In addition, the present invention also provides a testing method based on the above-mentioned single-phase single-beat stepper motor output torque testing device, which is characterized by comprising the following steps:

[0029] S1, the industrial computer powers on the motor 10 under test step by step according to the power-on time, so that the motor 10 under test rotates;

[0030] S2, during the rotation of the motor 10 under test, a load is applied to the motor 10 under test through the torque wheel 3, the thin wire 4, the large spring 5 and the small spring 6;

[0031] S3, after each power-on to the motor 10 under test, the industrial computer reads the torque value of the torque sensor 1 and the rotation angle value of the angle encoder 8;

[0032] S4, when the rotation angle value of the angle encoder 8 is less than the threshold angle after power-on once, the power-on is stopped, and the torque value of the torque sensor 1 read after the last power-on is set to be the maximum output capacity of the motor 10 under test.

[0033] Furthermore, the threshold angle is 90°.

[0034] In the above test principle, the large spring 5 and the small spring 6 are used to apply the load, mainly considering the initial tension of the spring and the maximum load of the spring. When the motor 10 under test starts to rotate, the small spring 6 is stretched by force, and because the pulling force does not reach the initial tension of the large spring 5, the large spring 5 does not deform. As the motor 10 under test continues to rotate, the pulling force increases, the small spring 6 reaches the maximum displacement, and the pulling force is greater than the initial tension of the large spring 5. The small spring 6 is fixed in the spring frame 7 and no longer continues to stretch and displace. As the pulling force increases, the large spring 5 begins to deform under force.

[0035] In the embodiment,

[0036] The gear ratio between the large gear 2 and the output shaft of the motor 10 under test is 13, and the gear ratio needs to be considered when converting torque. The diameter of the torque wheel in the test equipment is 10mm, so the length of the spring extension for each step (90° rotation) of the motor 10 under test is: a=10mm*pi / 13 / 4=0.6042mm.

[0037] The parameters of the selected small spring 6 are as follows: initial tension: 0.64N; maximum displacement: 42.7mm; maximum load: 5.72N; stiffness: 0.119N / mm; the test resolution of the output torque of the motor 10 under test is: 0.6042mm*0.119N / mm*5mm / 13=0.0277mNm; maximum range: (42.7mm*0.119N / mm+0.64N)*5mm / 13=2.2005mNm; initial measurement value: 0.64N*5mm / 13=0.2462mNm; the number of turns of the wire at the maximum range: 42.7mm / pi / 10=1.3592; the parameters of the selected large spring 7 are as follows : Initial tension: 2.94N: Maximum displacement: 106mm; Maximum load: 16.22N; Stiffness: 0.125N / mm; The measurement resolution: 0.6042mm*0.125N / mm*5mm / 13=0.0290mNm; Maximum measuring range: (106mm*0.125N / mm+2.94N)*5mm / 13=6.2269mNm; Initial measurement value: 2.94N*5mm / 13=1.1308mNm; The number of turns of the wire at maximum measuring range: 106mm / pi / 10mm=3.3741; Through the above analysis, the resolution of the measuring device is theoretically less than 1gf when the weight is hung.

[0038] The present invention is described in detail above in combination with specific implementation methods and exemplary examples. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments; the above description cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, the technical solution of the present invention and its implementation methods may be subjected to a variety of equivalent substitutions, modifications or improvements, all of which fall within the scope of the present invention; the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A single-phase single-beat stepper motor output torque test device, characterized in that: The test device comprises: a torque sensor (1), a large gear (2), a torque wheel (3), a thin wire (4), a large spring (5), a small spring (6), a spring frame (7), an angle encoder (8), an interface connector (9), an industrial computer and a fixed tooling of a motor to be tested (10); The large gear (2) is arranged to mesh with the output shaft gear of the motor (10) to be measured, the output shaft gear of the motor (10) to be measured meshes with the internal gear installed on the shaft of the angle encoder (8), the large gear (2) is connected to the input shaft of the torque sensor (1), the output shaft of the torque sensor (1) is equipped with a torque wheel (3), the torque wheel (3) is connected to one end of a small spring (6) arranged in a spring frame (7) through a thin wire (4), the other end of the small spring (6) is connected to one end of the inner side of the spring frame (7), the outer side of one end of the spring frame (7) connected to the small spring (6) is connected to one end of a large spring (5), and the other end of the large spring (5) is fixed.

2. The single-phase single-beat stepper motor output torque test device according to claim 1, characterized in that: The testing device also includes a motor driving circuit, and the motor driving circuit is provided with an H-bridge driving circuit.

3. The single-phase single-beat stepper motor output torque test device according to claim 2, characterized in that: The industrial computer controls the motor (10) to be tested via an H-bridge drive circuit, and the industrial computer is connected to an angle encoder (8) and a torque sensor (1).

4. The single-phase single-beat stepper motor output torque test device according to claim 1, characterized in that: The radius of the torque wheel (3) is 5 mm.

5. A testing method using a single-phase single-beat stepper motor output torque testing device according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1, the industrial computer powers on the motor (10) under test step by step according to the power-on time, so that the motor (10) under test rotates; S2, during the rotation of the motor (10) under test, a load is applied to the motor (10) under test through the torque wheel (3), the thin wire (4), the large spring (5), and the small spring (6); S3, after the industrial computer powers on the motor (10) under test each time, it reads the torque value of the torque sensor (1) and simultaneously reads the rotation angle value of the angle encoder (8); S4, when the rotation angle value of the angle encoder (8) is less than the threshold angle after power-on, power-on is stopped, and the torque value of the torque sensor (1) read after the last power-on is set to be the maximum output capacity of the motor (10) under test.

6. The testing method of a single-phase single-beat stepper motor output torque testing device according to claim 5, characterized in that: The threshold angle is 90°.

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