DV detection device of DC brush motor

Abstract

The utility model discloses a DV detection device of a DC brush motor, and aims to solve the problems that a piezoresistor of a conventional DC brush motor is fragile, easy to crack in the production process and difficult to distinguish in appearance, and especially after the motor is assembled, the piezoresistor is in the motor, and the quality of the piezoresistor is difficult to judge. The detection device comprises a motor tester, an oscilloscope, a PWM modulator and an insulating bottom plate, the output end of the motor tester is connected with the oscilloscope, the input end of the motor tester is connected with the PWM modulator, and a first conductive base and a second conductive base are installed on the upper surface of the insulating bottom plate. According to the utility model, the direct current brush motor is placed between the first conductive base and the second conductive base, PWM modulation voltage is adopted to drive the direct current brush motor to rotate, and the voltage dependent resistor of the direct current brush motor has the characteristic of consuming electric energy, so that the change of PWM average voltage can be monitored; therefore, whether the piezoresistor is good or not can be judged through the voltage change.

Description

Technical Field

[0001] The utility model belongs to the technical field of motor detection, and in particular relates to a DV detection device for a DC brushed motor. Background Art

[0002] When a brushed DC motor is in use, it will generate an electromotive force voltage opposite to the voltage while the motor rotates. This electromotive force voltage is called back electromotive force. The generation of back electromotive force will cause the commutator to seriously spark when switching current, which will affect the performance of the motor and may not meet the EMC management requirements.

[0003] To reduce the back electromotive force of a brushed DC motor, this voltage is consumed to minimize spark generation. Varistors (DVs) are typically installed on the commutator of the armature core. However, varistors are relatively fragile components and prone to cracking during the production process. They are difficult to distinguish visually, especially when the motor is in operation. Careful testing and research have revealed that the quality of a varistor can significantly change the voltage at the power supply end when the motor is operating at low duty cycles and high voltages. To address this issue, a DV detection device for a brushed DC motor is provided. Utility Model Content

[0004] (1) Technical problems to be solved

[0005] In response to the shortcomings of the existing technology, the purpose of the present utility model is to provide a DV detection device for a DC brush motor. The detection device is intended to solve the problem that the varistor of the existing DC brush motor is relatively fragile, easily cracked during the production process, and difficult to distinguish in appearance, especially when assembled into a motor, it is difficult to judge the quality of the varistor.

[0006] (2) Technical solution

[0007] In order to solve the above technical problems, the utility model provides a DV detection device for a DC brushed motor, which includes a motor tester, an oscilloscope, a PWM modulator and an insulating base plate. The output end of the motor tester is connected to the oscilloscope, the input end of the motor tester is connected to the PWM modulator, and a first conductive base and a second conductive base are installed on the upper surface of the insulating base plate, and both the first conductive base and the second conductive base are connected to the PWM modulator.

[0008] Preferably, a DC brush motor is provided between the first conductive base and the second conductive base, and the DC brush motor detects the varistor using PWM waveform changes.

[0009] Furthermore, threaded holes are provided on the lower surfaces of the first conductive base and the second conductive base, and two long holes are provided on the front and back sides of the insulating base. Screws are provided in the long holes and are threadedly connected to the threaded holes.

[0010] Furthermore, rectangular blocks are fixedly connected to the lower surfaces of the first conductive base and the second conductive base, threaded holes are opened on the rectangular blocks, and the rectangular blocks are slidably connected to the inside of the long holes.

[0011] Furthermore, the first conductive base and the second conductive base each include a conductive sheet and a fixed base. The conductive sheet is slidably connected to the top of the fixed base, and a spring is provided between the conductive sheet and the fixed base.

[0012] Furthermore, a cavity is opened inside the fixed base, and a rectangular column is fixedly connected to the lower surface of the conductive sheet. The bottom end of the rectangular column passes through the inner top wall of the cavity and is fixedly connected to the limiting block. The rectangular column is slidably connected to the fixed base, and a spring is sleeved on the outer surface of the rectangular column.

[0013] Furthermore, the four corners of the lower surface of the insulating base plate are fixedly connected with support legs, and the bottom ends of the support legs are fixedly connected with anti-sliding blocks.

[0014] (3) Beneficial effects

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] The utility model places a brushed DC motor between a first conductive base and a second conductive base, and adopts PWM modulation voltage to drive the brushed DC motor to rotate. Since the varistor of the brushed DC motor has the characteristic of consuming electric energy, the change of the PWM average voltage can be monitored, and the quality of the varistor can be judged by the voltage change. At the same time, the detection device is simple and easy to use, low in cost, and high in detection efficiency.

[0017] When the utility model places the DC brush motor on the first conductive base and the second conductive base, the positive and negative poles of the DC brush motor are in contact with the two conductive sheets. Since the conductive sheet is slidably connected above the fixed base, the conductive sheet moves downward and compresses the spring after being subjected to pressure. Even if the DC brush motor is placed tilted, the restoring force of the spring will cause the conductive sheet to move upward and fully contact the electrodes of the DC brush motor, thereby making the electrical connection more stable and more accurate during detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the circuit structure of the utility model.

[0019] Figure 2 It is a schematic diagram of the three-dimensional circuit structure of the utility model.

[0020] Figure 3It is a three-dimensional structural schematic diagram of a conductive sheet movably mounted on an insulating base plate of the utility model.

[0021] Figure 4 It is a schematic cross-sectional structure diagram of the conductive base of the present utility model.

[0022] Figure 5 It is a schematic diagram of the exploded structure of the insulating base plate of the utility model.

[0023] Figure 6 This is a schematic diagram of a normal PWM waveform of the present invention.

[0024] Figure 7 This is a schematic diagram of the PWM waveform when testing a brushed DC motor in the present invention.

[0025] The marks in the accompanying drawings are: 1. Motor tester; 2. Oscilloscope; 3. PWM modulator; 4. Insulating base; 5. First conductive base; 6. Second conductive base; 7. DC brush motor; 8. Threaded hole; 9. Long hole; 10. Screw; 11. Rectangular block; 12. Conductive sheet; 13. Fixed base; 14. Spring; 15. Cavity; 16. Rectangular column; 17. Limit block; 18. Support leg; 19. Anti-sliding block. DETAILED DESCRIPTION

[0026] This specific embodiment is a DV detection device for a DC brushed motor, and its structural diagram is shown in FIG. Figure 1-Figure 7 As shown, the detection device includes a motor tester 1, an oscilloscope 2, a PWM modulator 3 and an insulating base plate 4. The output end of the motor tester 1 is connected to the oscilloscope 2, and the input end of the motor tester 1 is connected to the PWM modulator 3. A first conductive base 5 and a second conductive base 6 are installed on the upper surface of the insulating base plate 4. The first conductive base 5 and the second conductive base 6 are both connected to the PWM modulator 3.

[0027] like Figure 1 and Figure 2 As shown: In this embodiment, a DC brush motor 7 is provided between the first conductive base 5 and the second conductive base 6 , and the DC brush motor 7 detects the varistor using PWM waveform changes.

[0028] This arrangement allows the brushed DC motor 7 to be placed between the first conductive base 5 and the second conductive base 6 , and a PWM modulation voltage is then used to drive the brushed DC motor 7 to rotate.

[0029] like Figure 2 and Figure 4 As shown: In this embodiment, threaded holes 8 are provided on the lower surfaces of the first conductive base 5 and the second conductive base 6, and two long holes 9 are provided on the front and back sides of the insulating base 4. Screws 10 are provided in the long holes 9, and the screws 10 are threadedly connected to the threaded holes 8.

[0030] The first conductive base 5 and the second conductive base 6 are arranged in this way so that they can move on the insulating base plate 4 , thereby adjusting the distance between the first conductive base 5 and the second conductive base 6 and detecting DC brushed motors 7 of different sizes.

[0031] like Figure 2 and Figure 5 As shown: In this embodiment, the lower surfaces of the first conductive base 5 and the second conductive base 6 are fixedly connected with a rectangular block 11, the threaded hole 8 is opened on the rectangular block 11, and the rectangular block 11 is slidably connected to the inside of the long hole 9.

[0032] In this way, the first conductive base 5 and the second conductive base 6 can only move along the long hole 9, thereby preventing the first conductive base 5 and the second conductive base 6 from rotating on the insulating bottom plate 4, and making the detection more stable.

[0033] like Figure 3-5 As shown: In this embodiment, the first conductive base 5 and the second conductive base 6 both include a conductive sheet 12 and a fixed base 13. The conductive sheet 12 is slidably connected above the fixed base 13. A spring 14 is arranged between the conductive sheet 12 and the fixed base 13. A cavity 15 is opened inside the fixed base 13. A rectangular column 16 is fixedly connected to the lower surface of the conductive sheet 12. The bottom end of the rectangular column 16 passes through the inner top wall of the cavity 15 and is fixedly connected to the limiting block 17. The rectangular column 16 is slidably connected to the fixed base 13, and the spring 14 is sleeved on the outer surface of the rectangular column 16.

[0034] When the brushed DC motor 7 is placed on the first conductive base 5 and the second conductive base 6 in this arrangement, the positive and negative poles of the brushed DC motor 7 are in contact with the two conductive plates 12. Since the conductive plates 12 are slidably connected above the fixed base 13, the conductive plates 12 move downward and compress the spring 14 after being subjected to pressure. Even if the brushed DC motor 7 is placed tilted, the restoring force of the spring 14 will cause the conductive plates 12 to move upward and fully contact the electrodes of the brushed DC motor 7, thereby making the electrical connection more stable and more accurate during detection.

[0035] like Figure 2 and Figure 3 As shown: In this embodiment, the four corners of the lower surface of the insulating base plate 4 are fixedly connected to support legs 18, and the bottom ends of the support legs 18 are fixedly connected to anti-sliding blocks 19. This arrangement suspends the insulating base plate 4 to prevent the screws 10 at the bottom from contacting the table top. At the same time, the anti-sliding blocks 19 increase friction to prevent sliding.

[0036] Working principle: When testing, set the parameters of PWM modulator 3, such as Figure 6As shown, the modulation voltage is 15KHZ, 15% duty cycle, if 30V is used for modulation, the average voltage is 4.5V. At this time, the DC brush motor 7 is placed between the first conductive base 5 and the second conductive base 6. At this time, PWM modulation voltage is used to drive the DC brush motor 7 to rotate. Since the varistor of the DC brush motor 7 has the characteristic of consuming electric energy, the change of the PWM average voltage can be monitored. By effectively utilizing the blank position of the duty cycle and the varistor characteristic, the collective reaction is reflected in the voltage change. By testing the current value of the debugging power supply, the performance of the internal DV can be judged, such as Figure 7 As shown, when the DV of the DC brush motor 7 is broken or defective, the voltage will be higher than 4.5V. After the DV is broken, it cannot offset the back electromotive force voltage, and the current is also high. When the DV of the DC brush motor 7 is used incorrectly and the capacity is too large, the voltage will be lower than 4.5V and the current will be too small. The quality of the varistor can be judged by the voltage change. Using a low-cost and high-efficiency improvement method can improve production quality, ensure product consistency, and improve customer satisfaction. At the same time, the detection device is simple and easy to use, and can be easily expanded horizontally. It can effectively detect and improve the performance of the motor and extend the service life of the motor.

[0037] All technical features in this embodiment can be freely combined according to actual needs.

[0038] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention can also be implemented in other ways. Any obvious replacement without departing from the concept of the present technical solution is within the scope of protection of the present invention.

Claims

1. A DV detection device for a brushed DC motor, comprising a motor tester (1), an oscilloscope (2), a PWM modulator (3) and an insulating base plate (4), characterized in that: The output end of the motor tester (1) is connected to an oscilloscope (2), the input end of the motor tester (1) is connected to a PWM modulator (3), and a first conductive base (5) and a second conductive base (6) are mounted on the upper surface of the insulating base plate (4), and both the first conductive base (5) and the second conductive base (6) are connected to the PWM modulator (3).

2. The DV detection device of a brushed DC motor according to claim 1, characterized in that: A DC brush motor (7) is provided between the first conductive base (5) and the second conductive base (6), and the DC brush motor (7) detects the varistor using PWM waveform changes.

3. The DV detection device of a brushed DC motor according to claim 2, characterized in that: The lower surfaces of the first conductive base (5) and the second conductive base (6) are both provided with threaded holes (8), and the front and rear sides of the insulating base plate (4) are provided with two long holes (9), wherein screws (10) are provided in the long holes (9), and the screws (10) are threadedly connected to the threaded holes (8).

4. The DV detection device of a brushed DC motor according to claim 3, characterized in that: The lower surfaces of the first conductive base (5) and the second conductive base (6) are both fixedly connected with a rectangular block (11), the threaded hole (8) is opened on the rectangular block (11), and the rectangular block (11) is slidably connected to the inside of the long hole (9).

5. The DV detection device of a brushed DC motor according to claim 1, characterized in that: The first conductive base (5) and the second conductive base (6) both comprise a conductive sheet (12) and a fixed base (13); the conductive sheet (12) is slidably connected above the fixed base (13); and a spring (14) is provided between the conductive sheet (12) and the fixed base (13).

6. The DV detection device of a brushed DC motor according to claim 5, characterized in that: A cavity (15) is provided inside the fixed base (13); a rectangular column (16) is fixedly connected to the lower surface of the conductive sheet (12); the bottom end of the rectangular column (16) passes through the inner top wall of the cavity (15) and is fixedly connected to a limiting block (17); the rectangular column (16) is slidably connected to the fixed base (13); and the spring (14) is sleeved on the outer surface of the rectangular column (16).

7. The DV detection device of a brushed DC motor according to claim 6, characterized in that: The four corners of the lower surface of the insulating bottom plate (4) are fixedly connected to support legs (18), and the bottom ends of the support legs (18) are fixedly connected to anti-sliding blocks (19).

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