Method for measuring the rotation speed of a small motor with a D-shaped shaft and device therefor

Abstract

The present application relates to the motor technical field, specifically, a kind of small motor rotating speed measurement method and device with D type shaft, device includes motor mounting seat, laser transmitter, the mounting plate of laser receiver, laser receiver, the motor mounting seat is arranged between laser transmitter and the mounting plate of laser receiver, and close to the position of laser transmitter, the laser receiver is installed in the light change area of laser irradiation that laser transmitter emits on the mounting plate of laser receiver.This application compared with prior art, the height difference of the measured motor D type shaft is amplified, so that laser sensor can collect signal, thereby realizing the indirect measurement of the rotating speed of small motor with D type shaft, measurement accuracy is improved to 0.1%, and the influence on motor load during measurement is not generated.

Description

Technical Field

[0001] This invention relates to the field of motor technology, specifically to a method and apparatus for measuring the speed of a small motor with a D-shaped shaft. Background Technology

[0002] In some applications of small DC motors, it is often necessary to measure the motor speed in order to correlate it with other motor performance characteristics.

[0003] Small motors with D-shaped shafts, such as Figure 1 As shown, the D-shaped shaft 10 is small in size and has a notch. Conventional methods for measuring motor speed have the following drawbacks, making them inaccurate in measuring motor speed: Direct encoder measurement: Due to the small size and low power of the motor, directly connecting a speed measuring device will inevitably affect the motor load and the accuracy of speed measurement.

[0004] Measurement method for attaching reflective markers to rotating axes: Due to the small size of the D-axis, it is impossible to accurately attach reflective markers.

[0005] The rotational speed is derived from the current acquisition and waveform analysis: due to differences in motor performance, there will be errors in waveform analysis.

[0006] Direct measurement using a through-beam laser sensor: Due to the small size of the D-axis, the laser sensor cannot directly identify it.

[0007] Therefore, it is necessary to design a method and device for measuring the speed of a small motor with a D-shaped shaft in order to accurately measure the motor speed. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method and device for measuring the speed of a small motor with a D-shaped shaft, so as to accurately measure the motor speed.

[0009] To achieve the above objectives, the present invention provides a method for measuring the speed of a small motor with a D-shaped shaft, comprising the following steps: Step 1: Fix the motor under test. The motor under test is located between the mounting plates of the laser transmitter and the laser receiver, and L2 = N × L1, where L2 is the horizontal distance between the center of the motor under test and the mounting plate of the laser receiver, L1 is the horizontal distance between the center of the motor under test and the laser transmitter, and N is the magnification factor.

[0010] Step 2: The laser emitter is powered on and emits a laser.

[0011] Step 3: Rotate the D-shaft of the motor under test so that the notch plane of the D-shaft is 90° to the horizontal direction, which is the first limit position. Record the first position of the light that shines on the mounting plate of the laser receiver.

[0012] Step 4: Rotate the D-shaft of the motor under test so that the notch plane of the D-shaft faces upward and is in the horizontal direction, which is the second limit position. Record the second bright position of the laser beam illuminating the mounting plate of the laser receiver.

[0013] Step 5: Install the laser receiver between the first and second bright positions, and the distance H2 between the first and second bright positions is greater than the diameter of the laser receiver.

[0014] Step 6: Apply normal voltage to the motor under test. The test software calculates the speed of the motor under test as n = 60 × 1000 / S, where S is the time interval between two signals received by the laser receiver.

[0015] Optionally, before the motor under test is supplied with normal voltage, a pre-adjustment step for the laser receiver is also included: the motor under test is supplied with low voltage, the motor under test is rotated slowly, and it is confirmed that the installation position of the laser receiver is in the area of ​​change in the light intensity of the laser irradiation, and the laser receiver receives a signal once for each rotation of the motor under test.

[0016] Optionally, the distance H2 between the first and second illuminated positions is N×H1, where H1 is the height of the D-shaped shaft notch.

[0017] Optionally, step 2 further includes adjusting the position of the laser emitter so that the laser emitter and the notch plane of the D-shaped shaft of the motor under test are at the same horizontal level.

[0018] An apparatus for measuring the speed of a small motor with a D-axis includes a motor mounting base, a laser emitter, a mounting plate for a laser receiver, and a laser receiver. The motor mounting base is disposed between the laser emitter and the mounting plate for the laser receiver, and is located close to the laser emitter. The laser receiver is mounted on the mounting plate for the laser receiver within the area of ​​light variation irradiated by the laser emitted by the laser emitter.

[0019] Optionally, the motor mounting base is a contoured structure of the motor under test.

[0020] Optionally, the motor mounting base is provided with a cover plate on top, which covers the top of the motor under test, and a locking mechanism is provided between the cover plate and the motor mounting base.

[0021] Optionally, the laser emitted by the laser emitter is parallel light, and the output spot size is less than or equal to the diameter of the D-shaped shaft. The frequency of the laser receiver is matched with the theoretical speed of the motor under test.

[0022] Optionally, a bracket is installed on the side of the motor mounting base away from the laser receiver, the laser emitter is slidably mounted on the bracket, and the laser receiver is slidably mounted on the laser receiver mounting plate.

[0023] Optionally, the signal output terminal of the laser receiver is connected to a data acquisition card installed on a computer. The computer has acquisition software installed, which calculates the high-frequency signal acquired by the data acquisition card and displays the calculation result on the computer's monitor.

[0024] Optionally, the signal output terminal of the laser receiver is connected to the PLC high-speed counting module, and the PLC calculates the high-frequency signal collected by the high-speed counting module and displays the calculation result on the display.

[0025] Compared with the prior art, the present invention amplifies the height difference of the D-shaped shaft of the motor under test, so that the laser sensor can collect the signal, thereby realizing the indirect measurement of the speed of a small motor with a D-shaped shaft, improving the measurement accuracy to 0.1%, and without affecting the motor load during the measurement process. Attached Figure Description

[0026] Figure 1 This is a top view of a small motor with a D-shaped shaft.

[0027] Figure 2 This is a schematic diagram showing the height of the D-shaped shaft notch.

[0028] Figure 3 This is a schematic diagram of the small motor speed measuring device with a D-shaped shaft according to the present invention.

[0029] Explanation of reference numerals in the attached diagram: 1 is the cover plate, 2 is the bracket, 3 is the laser emitter, 4 is the motor mounting base, 5 is the laser receiver, 6 is the mounting plate of the laser receiver, 10 is the D-axis, 71 is the first extreme position, 72 is the second extreme position, 81 is the first bright position, and 82 is the second bright position. Implementation

[0030] The present invention will now be further described with reference to the accompanying drawings.

[0031] This invention provides a method for measuring the speed of a small motor with a D-shaped shaft, comprising the following steps: Step 1: Fix the motor under test. The motor under test is located between the mounting plates of the laser transmitter and the laser receiver, and L2 = N × L1, where L2 is the horizontal distance between the center of the motor under test and the mounting plate of the laser receiver, L1 is the horizontal distance between the center of the motor under test and the laser transmitter, and N is the magnification factor.

[0032] Step 2: The laser emitter is powered on and emits a laser.

[0033] In step 2, the position of the laser emitter can be adjusted so that the laser emitter and the notch plane of the D-shaped shaft of the motor under test are at the same horizontal level, so that the first and second extreme positions in steps 3 and 4 are within a controllable range, and the brightness change area is prevented from exceeding the height of the laser receiver mounting plate.

[0034] Step 3: Rotate the D-shaft of the motor under test so that the notch plane of the D-shaft is 90° to the horizontal direction, which is the first limit position. Record the first position of the light that shines on the mounting plate of the laser receiver.

[0035] Step 4: Rotate the D-shaft of the motor under test so that the notch plane of the D-shaft faces upward and is in the horizontal direction, which is the second limit position. Record the second bright position of the laser beam illuminating the mounting plate of the laser receiver.

[0036] Step 5: Install the laser receiver between the first and second bright positions, and the distance H2 between the first and second bright positions is greater than the diameter of the laser receiver.

[0037] Step 6: Apply normal voltage to the motor under test. The test software calculates the speed of the motor under test as n = 60 × 1000 / S, where S is the time interval between two signals received by the laser receiver.

[0038] Before applying normal voltage to the motor under test, a pre-adjustment step for the laser receiver is included: The motor is given a low voltage and rotated slowly to confirm that the laser receiver is installed in the area of ​​varying laser illumination, and that the laser receiver receives a signal once for each rotation of the motor. This step of setting the laser receiver's installation position and confirming its reception is to further improve the accuracy and effectiveness of motor speed measurement.

[0039] The distance H2 between the first and second illuminated positions is N × H1, where H1 is the height of the D-shaped shaft notch. Figure 2 As shown, the height of the D-shaped axial notch is magnified by N times to form a brightness variation area with a height of H2 that covers the laser receiver 5.

[0040] The area between illuminated position 81 and illuminated position 82 is the illumination variation zone. When the notched plane of the D-shaft 10 of the motor under test is facing upward and horizontal, the illumination variation zone is completely illuminated by the laser emitted by the laser emitter 3, and the laser receiver 5 receives the signal. As the D-shaft 10 rotates, the laser emitted by the laser emitter 3 is blocked, and the laser receiver 5 cannot receive the laser. This continues until the D-shaft 10 of the motor under test rotates one revolution, and the notched plane of the D-shaft 10 returns to its initial position. At this point, the illumination variation zone is again completely illuminated by the laser emitted by the laser emitter 3, and the laser receiver 5 receives the signal. Therefore, the laser receiver 5 receives one signal for every revolution of the D-shaft 10 of the motor under test.

[0041] See Figure 3 An apparatus for measuring the speed of a small motor with a D-axis includes a motor mounting base 4, a laser emitter 3, a laser receiver mounting plate 6, and a laser receiver 5. The motor mounting base 4 is positioned between the laser emitter 3 and the laser receiver mounting plate 6, and close to the laser emitter 3. The laser receiver 5 is mounted on the laser receiver mounting plate 6 within the area of ​​light variation irradiated by the laser emitted by the laser emitter 3.

[0042] The motor mounting base 4 is a contour structure of the motor under test, ensuring that the position of the motor under test is unique and adjustable.

[0043] A cover plate 1 is provided on the top of the motor mounting base 4. The cover plate 1 covers the top of the motor under test. A locking mechanism is provided between the cover plate 1 and the motor mounting base 4 to ensure that the motor under test will not jump during operation, thereby further improving the measurement accuracy.

[0044] The laser emitted by laser emitter 3 is parallel light, and the output spot is less than or equal to the diameter of the D-shaped shaft. The frequency of laser receiver 4 is matched with the theoretical speed of the motor under test.

[0045] A bracket 2 is mounted on the side of the motor mounting base 4 away from the laser receiver 5. The laser emitter 3 is slidably mounted on the bracket 2 to facilitate vertical adjustment of the laser emitter 3's position. The laser receiver 5 is slidably mounted on the laser receiver mounting plate 6 to facilitate vertical adjustment of the laser receiver 5's position, allowing the laser receiver 5 to receive the laser emitted by the laser emitter 3.

[0046] The signal output terminal of the laser receiver 5 is connected to the data acquisition card installed on the computer. The computer has acquisition software installed, which calculates the high-frequency signal acquired by the data acquisition card and displays the calculation result on the computer's monitor.

[0047] The signal output terminal of the laser receiver 5 is connected to the PLC high-speed counting module. The PLC calculates the high-frequency signal collected by the high-speed counting module and displays the calculation result on the display.

[0048] This invention amplifies the height difference of the D-shaft of the motor under test, so that the laser sensor can collect the signal, thereby realizing the indirect measurement of the speed of a small motor with a D-shaft, improving the measurement accuracy to 0.1%, and without affecting the motor load during the measurement process. Example

[0049] In this example, the magnification N is 20, the diameter of the laser receiver 5 is 2mm, and the height H1 of the D-shaped shaft notch is 0.4mm.

[0050] See Figure 3 The motor under test is placed on the motor mounting base 4, and the cover plate 1 is placed on the motor under test and fixed to the motor mounting base 4. A bracket 2 is provided on one side of the motor under test, and a laser emitter 3 is installed on the bracket 2. The horizontal distance L1 between the center of the motor under test and the laser emitter is 20 mm. A laser receiver mounting plate 6 is provided on the other side of the motor under test. The horizontal distance L2 between the center of the motor under test and the laser receiver mounting plate is N×L1=400 mm.

[0051] The laser emitter 3 is powered on and emits a laser. The position of the laser emitter 3 on the bracket 2 is adjusted so that the laser emitter 3 is parallel to the D-shaped shaft 10 of the motor under test.

[0052] Rotate the D-shaft 10 of the motor under test until the notch plane of the D-shaft 10 forms a 90° angle with the horizontal direction, which is the first limit position 71. Record the position 81 of the light shining on the mounting plate 6 of the laser receiver. Rotate the D-shaft 10 of the motor under test until the notch plane of the D-shaft 10 is in the horizontal direction, which is the second limit position 72. Record the position 82 of the light shining on the mounting plate 6 of the laser receiver.

[0053] The laser receiver 5 is installed between the first bright position 81 and the second bright position 82. The distance between the first bright position 81 and the second bright position 82 is H2=N×H1=8mm, which is greater than the diameter of the laser receiver 5.

[0054] The motor under test is supplied with a low voltage and rotates slowly. This confirms that the installation position of the laser receiver 5 is in the area of ​​change in light intensity under laser illumination, and that the laser receiver 5 receives a signal once for each rotation of the motor under test.

[0055] The motor under test is supplied with normal voltage. The data acquisition card acquires the high-frequency signal received by the laser receiver 5. Then, LabVIEW is used to calculate the time interval S between the two signals received by the laser receiver. S is 75ms. The test software calculates the speed of the motor under test as n = 60 × 1000 / S = 800 r / min.

Claims

1. A method for measuring the speed of a small motor with a D-shaped shaft, characterized in that: Includes the following steps: Step 1: Fix the motor under test. The motor under test is located between the mounting plates of the laser emitter and the laser receiver, and L2 = N × L1, where L2 is the horizontal distance between the center of the motor under test and the mounting plate of the laser receiver, L1 is the horizontal distance between the center of the motor under test and the laser emitter, and N is the magnification factor. Step 2: The laser emitter is powered on and emits a laser. Step 3: Rotate the D-shaft of the motor under test so that the notch plane of the D-shaft is 90° to the horizontal direction, which is the first limit position. Record the first position of the light shining on the mounting plate of the laser receiver. Step 4: Rotate the D-shaft of the motor under test so that the notch plane of the D-shaft faces upward and is in the horizontal direction, which is the second limit position. Record the second position of the light shining on the mounting plate of the laser receiver. Step 5: Install the laser receiver between the first bright position and the second bright position, and the distance H2 between the first bright position and the second bright position is greater than the diameter of the laser receiver. Step 6: Apply normal voltage to the motor under test. The test software calculates the speed of the motor under test as n = 60 × 1000 / S, where S is the time interval between two signals received by the laser receiver.

2. The method for measuring the speed of a small motor with a D-shaped shaft according to claim 1, characterized in that: Before the motor under test is supplied with normal voltage, a pre-adjustment step for the laser receiver is also included: the motor under test is supplied with low voltage, the motor under test is rotated slowly, and it is confirmed that the installation position of the laser receiver is in the area of ​​change in the light intensity of the laser irradiation, and the laser receiver receives a signal once for each rotation of the motor under test.

3. The method for measuring the speed of a small motor with a D-shaped shaft according to claim 1, characterized in that: The distance H2 between the first and second bright positions is N×H1, where H1 is the height of the D-shaped shaft notch.

4. The method for measuring the speed of a small motor with a D-shaped shaft according to claim 1, characterized in that: Step 2 further includes adjusting the position of the laser emitter so that the laser emitter and the notch plane of the D-shaped shaft of the motor under test are at the same horizontal height.

5. An apparatus for performing the method for measuring the speed of a small motor with a D-shaped shaft as described in claim 1, characterized in that: The device includes a motor mounting base (4), a laser emitter (3), a laser receiver mounting plate (6), and a laser receiver (5). The motor mounting base (4) is located between the laser emitter (3) and the laser receiver mounting plate (6), and close to the laser emitter (3). The laser receiver (5) is mounted on the laser receiver mounting plate (6) within the area of ​​light variation irradiated by the laser emitted by the laser emitter (3).

6. The apparatus for measuring the speed of a small motor with a D-shaped shaft according to claim 5, characterized in that: The motor mounting base (4) is a contour structure of the motor under test.

7. The apparatus for measuring the speed of a small motor with a D-shaped shaft according to claim 5, characterized in that: The motor mounting base (4) is provided with a cover plate (1) on top, which covers the top of the motor under test. A locking mechanism is provided between the cover plate (1) and the motor mounting base (4).

8. The apparatus for measuring the speed of a small motor with a D-shaped shaft according to claim 5, characterized in that: The laser emitted by the laser emitter (3) is parallel light, and the output spot is less than or equal to the diameter of the D-shaped shaft. The frequency of the laser receiver (5) is matched with the theoretical speed of the motor under test.

9. The apparatus for measuring the speed of a small motor with a D-shaped shaft according to claim 5, characterized in that: The motor mounting base (4) is equipped with a bracket (2) on the side away from the laser receiver (5). The laser emitter (3) is slidably mounted on the bracket (2), and the laser receiver (5) is slidably mounted on the mounting plate (6) of the laser receiver.

10. The apparatus for measuring the speed of a small motor with a D-shaped shaft according to claim 5, characterized in that: The signal output terminal of the laser receiver (5) is connected to the data acquisition card installed on the computer. The computer has acquisition software installed. The acquisition software calculates the high-frequency signal acquired by the data acquisition card and displays the calculation result on the computer's monitor.

11. The apparatus for performing a method for measuring the speed of a small motor with a D-shaped shaft according to claim 5, characterized in that: The signal output terminal of the laser receiver (5) is connected to the PLC high-speed counting module. The PLC calculates the high-frequency signal collected by the high-speed counting module and displays the calculation result on the display.

Images