A motor with anti-electromagnetic interference function

Abstract

The utility model relates to motor technical field, concretely is a kind of motor with anti-electromagnetic interference function.The utility model discloses a kind of motor with anti-electromagnetic interference function, including shell, the shell outside power supply line inlet is provided with PCB board, first wire hole and second wire hole and first mounting hole and second mounting hole are equipped on PCB board, and PCB board is fixed and grounded by first mounting hole and second mounting hole with shell installation and ground conduction, at least one group X2Y capacitor is arranged on the PCB board, positive line is electrically connected with the one end of X capacitor of X2Y capacitor and the one end of one Y capacitor, negative line is electrically connected with the other end of X capacitor of X2Y capacitor and the one end of another Y capacitor.The utility model has the advantages of further amplifying the shielding effect on electromagnetic radiation, effectively reducing electromagnetic radiation through power line conduction interference to power grid or other equipment.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, specifically to a motor with anti-electromagnetic interference function. Background Technology

[0002] Chinese patent application No. 202123376328.8 discloses an electromagnetic compatibility circuit for a brushed DC motor, including a power supply, a varistor VS, capacitors C1, C2, and C3, inductors L1 and L2, capacitors C4, C5, and C6, capacitor X2Y, and a motor M. The varistor VS and capacitor C1 are connected across the positive and negative terminals of the power supply, respectively. Inductors L1 and L2 are connected in series across the two ends of the motor M, respectively. Capacitors C2 and C3 are connected in series and then across the positive and negative terminals of the power supply. A grounding wire is also provided between capacitors C2 and C3. Capacitors C4 and X2Y are connected across the positive and negative terminals of the power supply, respectively. Capacitors C5 and C6 are connected in series and then across the positive and negative terminals of the power supply. A grounding wire is also provided between capacitors C5 and C6.

[0003] In the above technical solution, a varistor VS is connected in parallel between the power lines to suppress surge voltage; capacitors C1 and C4 are connected in parallel between the power lines to suppress differential-mode interference signals between different frequencies; capacitors C2, C3, C5, and C6 are connected in parallel between the power lines to suppress common-mode interference signals between different frequencies; and an X2Y capacitor is connected in parallel between the power lines to suppress high-frequency signals. However, this technical solution does not consider the impact of the installation position of the printed circuit board with the X2Y capacitor on the suppression of electromagnetic radiation. Therefore, the installation position of the printed circuit board itself is not optimized to amplify the suppression effect of the printed circuit board with the X2Y capacitor on the electromagnetic radiation generated by the motor, thereby avoiding electromagnetic radiation from being conducted through the power lines to interfere with the power grid or other equipment. Therefore, the shielding effect of the above technical solution on electromagnetic radiation is not good. Utility Model Content

[0004] The purpose of this invention is to provide a motor with anti-interference function that can be optimized for the installation position of the printed circuit board itself to amplify the shielding effect against electromagnetic radiation.

[0005] To achieve the above objectives, this utility model discloses a motor with anti-electromagnetic interference function, including a housing. Inside the housing are a stator, a rotor capable of rotating relative to the stator, carbon brushes, and a commutator. A PCB board is provided at the power supply line inlet on the outside of the housing. The PCB board has a first wire through hole, a second wire through hole, a first mounting hole, and a second mounting hole. The PCB board is fixed to the housing and grounded through the first and second mounting holes. At least one set of X2Y capacitors is disposed on the PCB board. The positive and negative wires of the motor power line enter the motor through the first and second wire through holes and connect to the carbon brushes. The positive wire is electrically connected to one end of the X capacitor and one end of one of the Y capacitors in the X2Y capacitor. The negative wire is electrically connected to the other end of the X capacitor and one end of the other Y capacitor in the X2Y capacitor. The other ends of the two Y capacitors in the X2Y capacitor are grounded through the PCB board.

[0006] During the sliding contact between the carbon brush and the commutator, the unstable contact between them due to their relative motion can cause instantaneous changes in current, resulting in electric sparks that act as a source of high-frequency electromagnetic radiation. These sparks can interfere with surrounding electronic equipment through both spatial radiation and conduction via wires. Since the metal material of the motor housing itself can shield the electromagnetic radiation generated by the electric sparks to a certain extent, the gap where the motor power line enters the housing is where the electromagnetic radiation intensity is highest. By installing a PCB board with capacitors that shield electromagnetic interference signals at the motor wiring location and electrically connecting the PCB board to the motor power line, the electromagnetic radiation can be shielded at the end of the path from the motor housing. This, in conjunction with the motor housing, can further enhance the shielding effect against electromagnetic radiation.

[0007] This invention involves installing a PCB board with an X2Y capacitor at the point where the motor power line passes through the motor housing. This allows the PCB board with the X2Y capacitor to be positioned at the location within the motor housing where electromagnetic radiation leakage is highest (i.e., where the motor power line enters the housing). This prevents high-frequency electromagnetic radiation generated between the carbon brushes and the commutator from radiating to the outside from where the motor power line enters the housing, achieving comprehensive suppression of electromagnetic radiation. This more effectively shields and suppresses electromagnetic radiation, ensuring the motor meets EMC standards. Furthermore, this invention further amplifies the shielding effect against electromagnetic radiation and effectively reduces electromagnetic radiation interference transmitted to the power grid or other equipment via the power line.

[0008] Preferably, the housing has a boss at the position where the power cord passes through, and the end of the boss away from the housing is a rectangular plane for mounting the PCB board. The PCB board is mounted on the rectangular plane, which facilitates the installation of the PCB board and reduces the process difficulty of installing the PCB board.

[0009] Preferably, the PCB board is provided with a positive port and a negative port that are electrically connected to the positive and negative lines in the power line, respectively. A differential mode circuit is provided between the positive port and the negative port, and the differential mode circuit includes two X2Y capacitors connected in parallel.

[0010] By setting two X2Y capacitors connected in parallel on the PCB board, the X capacitor and Y capacitor are used together to more comprehensively suppress different types of EMI and form a complete filter network.

[0011] Preferably, the PCB board is also provided with two grounding ports, which are located at both ends of the PCB board along its length, and the positive and negative ports are located between the two grounding ports.

[0012] By setting a grounding port, the high-frequency electromagnetic radiation generated between the carbon brush and the commutator can be conducted to the ground through the power line.

[0013] Preferably, the end face of the PCB board that contacts the rectangular plane is divided into an insulating area and a grounding area. The insulating area covers the positive terminal, the negative terminal, and the pins of the two X2Y capacitors, and the grounding area covers the two grounding ports and surrounds the outside of the insulating area.

[0014] By increasing the contact area of ​​the grounding region, the efficiency of high-frequency electromagnetic radiation being conducted to the ground through the power line is improved.

[0015] Preferably, the boss is provided with a threaded hole at the position corresponding to the grounding port. The boss is fastened to the PCB board by fastening bolts and they are tightly attached to each other, thereby ensuring the stability of the PCB board.

[0016] Preferably, the platform is fitted with a protective cover for protecting the positive port, negative port and ground port, and the protective cover is fixedly installed on the boss by fastening bolts.

[0017] By installing a protective cover at the entry point of the motor power cord into the housing, the PCB board is protected to prevent dust or water droplets from adhering to the PCB board, which could cause short circuits or leakage, or even affect the normal operation of the equipment.

[0018] Preferably, the power cord is a four-core wire, which includes a positive wire electrically connected to the positive terminal of the PCB board, a negative wire electrically connected to the negative terminal of the PCB board, an electromagnetic brake wire electrically connected to the electromagnetic brake module, and a power supply wire. By integrating the positive wire, negative wire, electromagnetic brake wire, and power supply wire into a four-core wire, the wiring of the motor can be made simpler and more practical compared to setting up multiple scattered wires for separate electrical connections.

[0019] Preferably, the positive and negative wires pass through the PCB board in a solder section without an insulating layer. The solder section is electrically connected to the PCB board through a soldering process. By exposing the metal wires at the point where the positive and negative wires pass through the PCB board, it is easier to solder the positive and negative wires to the positive and negative ports of the PCB board, respectively, thereby achieving an electrical connection between the wires and the ports.

[0020] This invention can prevent the high-frequency electromagnetic radiation source generated between the carbon brush and the commutator from being emitted to the outside from the point where the motor power line enters the housing, so that the motor meets EMC standards. It has the advantages of further amplifying the shielding effect against electromagnetic radiation and effectively reducing electromagnetic radiation interference to the power grid or other equipment through the power line. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of one structure of the present utility model.

[0022] Figure 2 This is a schematic diagram of the structure of the protective cover of this utility model after it is opened.

[0023] Figure 3 This is a schematic diagram of the reverse side of the PCB board of this utility model.

[0024] Figure 4 This is a measurement diagram of the horizontal electromagnetic radiation interference generated by this invention.

[0025] Figure 5 This is a measurement diagram of the vertical electromagnetic radiation interference generated by this invention.

[0026] In the diagram: 11. Housing; 12. Boss; 121. Rectangular plane; 13. Protective cover; 131. Lead tube; 14. Power cord; 15. Positive wire; 16. Negative wire; 17. Electromagnetic brake wire; 18. Power supply wire; 19. Fastening bolt; 20. PCB board. Detailed Implementation

[0027] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0028] Depend on Figure 1As shown, this embodiment discloses a motor with anti-electromagnetic interference function, including a housing 11 for protecting internal electronic components. The housing 11 houses a stator, a rotor capable of rotating relative to the stator, carbon brushes, and a commutator. A power cord 14 for electrical connection with a motor controller is provided on the housing 11. A boss 12 is provided on the housing 11 corresponding to the position through which the power cord 14 passes. The end of the boss 12 away from the housing 11 is a rectangular plane 121 for mounting a PCB board 20. One end of the power cord 14 is electrically connected to the motor controller. The power cord 14 is a four-core wire. It includes a positive wire 15 electrically connected to the positive terminal of the PCB board 20, a negative wire 16 electrically connected to the negative terminal of the PCB board 20, an electromagnetic brake wire 17 electrically connected to the electromagnetic brake module, and a power supply wire 18. The other ends of the positive wire 15 and the negative wire 16 in the power supply wire 14 pass through the PCB board 20 set on the boss 12 and extend into the motor, and then are electrically connected to the carbon brushes located on both sides of the motor. The position where the positive wire 15 and the negative wire 16 pass through the PCB board 20 is a solder section without an insulating layer. The solder section is electrically connected to the PCB board 20 through the soldering process.

[0029] The PCB board 20 is provided with a positive port M+, a negative port M- for the positive line 15 and the negative line 16 to be electrically connected respectively, and two ground ports GND. A differential mode circuit is provided between the positive port and the negative port. The differential mode circuit includes a first X2Y capacitor C1 and a second X2Y capacitor C2 connected in parallel. The two ground ports are located at both ends of the length direction of the PCB board 20 respectively, and the positive port and the negative port are located between the two ground ports.

[0030] Depend on Figure 3 As shown, the end face of the PCB board 20 that contacts the rectangular plane 121 is divided into an insulating area and a grounding area. The insulating area covers the positive terminal, the negative terminal, and the pins of the two X2Y capacitors, while the grounding area covers the two grounding ports and surrounds the outside of the insulating area.

[0031] Positive wire 15 and negative wire 16 enter the motor through positive port M+ and negative port M- respectively and are connected to the carbon brush. Positive wire 15 is electrically connected to one end of the X capacitor of the first X2Y capacitor C1 and the second X2Y capacitor C2 and one end of the Y capacitor of one of them. Negative wire 16 is electrically connected to the other end of the X capacitor of the first X2Y capacitor C1 and the second X2Y capacitor C2 and one side of the other Y capacitor. The other end of the Y capacitor is grounded through the grounding area on the reverse side of the PCB board 20.

[0032] The boss 12 has a threaded hole at the position corresponding to the grounding port GND. The boss 12 is fastened to the PCB board 20 by the fastening bolt 19 and they are tightly attached to each other.

[0033] When the fastening bolt 19 locks the PCB board 20 onto the boss 12, the grounding area on the reverse side of the PCB board 20 is in close contact with the boss 12, thus achieving an electrical connection between the PCB board 20 and the housing 11.

[0034] Depend on Figure 2 As shown, a protective cover 13 for protecting the positive terminal, negative terminal and grounding terminal is fastened on the platform. The protective cover 13 is fixedly installed on the boss 12 by fastening bolts 19. The protective cover 13 is provided with a lead tube 131 for the four-core wire to pass through.

[0035] After the protective cover 13 is attached to the boss 12, the boss 12 consists of the PCB board 20 and the protective cover 13 in sequence along the direction away from the motor axis. The positive wire 15 and negative wire 16, as well as the power supply wire 18 and electromagnetic brake wire 17, which are electrically connected to the PCB board 20, all pass through the lead tube 131 to the outside of the protective cover 13, thereby connecting to the motor controller.

[0036] The instantaneous change in current caused by the relative movement between the carbon brush and the commutator generates an electric spark, which acts as a source of high-frequency electromagnetic radiation. This spark can interfere with surrounding electronic equipment through both spatial radiation and conduction via wires. Since the metal material of the motor housing 11 itself can shield the electromagnetic radiation generated by the electric spark to a certain extent, the gap where the motor power line 14 enters the housing 11 is the point of highest electromagnetic radiation intensity. By installing a PCB board 20 with two X2Y capacitors connected in parallel at the point where the power line 14 enters the housing 11, and electrically connecting the positive and negative ports on the PCB board 20 to the positive line 15 and the negative line 16, the electromagnetic radiation is grounded when passing through the PCB board 20. This achieves shielding at the end of the path from the motor housing 11, further enhancing the shielding effect against electromagnetic radiation in conjunction with the motor housing 11.

[0037] After treatment using this method, the electromagnetic radiation emitted by the motor that interferes with external electrical equipment is based on the standards set by the International Special Committee on Radio Interference (CISPR). The results of simultaneous horizontal measurements of motors numbered 3 and 7 are as follows: Figure 4 As shown, the results of the vertical measurements are as follows: Figure 5 As shown, the horizontal axis represents the frequency of electromagnetic radiation in MHz, and the vertical axis represents the amplitude of electromagnetic radiation in dBuV; the maximum value of PK and the average value of repeated measurements at the current frequency that is closest to the standard extreme value are both lower than the extreme value specified by CISPR.

Claims

1. A motor with electromagnetic interference resistance, comprising a housing, wherein a stator, a rotor rotatable relative to the stator, brushes, and a commutator are disposed within the housing, characterized in that: A PCB board is provided at the power supply line inlet on the outside of the housing. The PCB board has a first wire through hole and a second wire through hole, as well as a first mounting hole and a second mounting hole. The PCB board is fixed to the housing and grounded through the first mounting hole and the second mounting hole. At least one set of X2Y capacitors is provided on the PCB board. The positive and negative wires of the motor power line enter the motor through the first wire through hole and the second wire through hole, respectively, and are connected to the brushes. The positive wire is electrically connected to one end of the X capacitor and one end of one of the Y capacitors of the X2Y capacitor. The negative wire is electrically connected to the other end of the X capacitor and one end of the other Y capacitor of the X2Y capacitor. The other ends of the two Y capacitors of the X2Y capacitor are grounded through the PCB board.

2. The motor with anti-electromagnetic interference function according to claim 1, characterized in that: The housing has a protrusion at the position where the power cord passes through. The end of the protrusion away from the housing is a rectangular plane for mounting a PCB board, and the PCB board is mounted to the rectangular plane.

3. A motor with anti-electromagnetic interference function according to claim 1 or 2, characterized in that: The PCB board is provided with a positive port and a negative port serving as a first wire hole and a second wire hole. The positive port and the negative port are electrically connected to the positive line and the negative line in the power line, respectively. A differential mode circuit is provided between the positive port and the negative port, and the differential mode circuit includes two sets of X2Y capacitors connected in parallel.

4. A motor with anti-electromagnetic interference function according to claim 3, characterized in that: The PCB board has two grounding ports, which serve as the first mounting hole and the second mounting hole. The two grounding ports are located at both ends of the length direction of the PCB board, and the positive port and the negative port are located between the two grounding ports.

5. A motor with anti-electromagnetic interference function according to claim 4, characterized in that: The end face of the PCB board that contacts the rectangular plane is divided into an insulating area and a grounding area. The insulating area covers the positive terminal, the negative terminal, and the pins of the two X2Y capacitors. The grounding area covers the two grounding ports and surrounds the outside of the insulating area.

6. A motor with anti-electromagnetic interference function according to claim 5, characterized in that: The boss has a threaded hole at the position corresponding to the grounding port. The boss is used to fasten the PCB board and make them fit together tightly by fastening bolts.

7. A motor with anti-electromagnetic interference function according to claim 6, characterized in that: The platform is fitted with protective covers for protecting the positive terminal, negative terminal, and grounding terminal. The protective covers are fixedly installed on the boss by fastening bolts.

8. A motor with anti-electromagnetic interference function according to claim 1, characterized in that: The power cable is a four-core cable, which includes a positive wire electrically connected to the positive terminal of the PCB board, a negative wire electrically connected to the negative terminal of the PCB board, an electromagnetic brake wire electrically connected to the electromagnetic brake module, and a power supply wire.

9. A motor with anti-electromagnetic interference function according to claim 3, characterized in that: The positive and negative lines pass through the positive and negative ports in solder sections without insulation, and these solder sections are electrically connected to the pads or solder joints on the PCB board via solder.

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