A motor structure with EMC anti-interference

Abstract

The utility model discloses a kind of motor structures with EMC anti-interference, belong to motor technical field, including motor main body, motor main body includes metal shell, rotor, stator, end cap being set at the both ends of metal shell and power supply wiring terminal being led out from end cap, filter assembly and surge absorption assembly are arranged in motor main body inside, filter assembly is set in the inner chamber of metal shell, and directly cross connects between power supply wiring terminal, surge absorption assembly is set in the inner chamber of metal shell;The utility model directly embeds filter assembly and surge absorption assembly in the inside of the metal shell of motor, by directly arranging counter element in motor, the most direct intervention is realized, filter assembly is responsible for providing nearby, low impedance discharge loop for high-frequency noise, prevent it from escaping to external power grid through power supply wiring terminal;Surge absorption assembly is responsible for instantaneous response abnormal high pressure, absorbs the energy clamping, effectively realizes the source control of EMC processing.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, and in particular to a motor structure with EMC anti-interference. Background Technology

[0002] In numerous technological fields such as modern industrial automation, smart homes, automotive electronics, and precision instruments, motors, as core power actuators, are ubiquitous. From the rotor drive of miniature drones to the control of large industrial robotic arms, from the rotation of fans in household appliances to the raising and lowering of windows and doors in vehicles, the stable and reliable operation of motors is fundamental to ensuring the normal functioning of the entire system. However, motors, especially brushed DC motors and brushless motors driven by pulse width modulation, are inherently strong sources of electromagnetic interference during operation. The switching between the brushes and the commutator generates broadband electrical spark noise, while the winding inductance induces high-frequency voltage spikes when current changes suddenly. This electromagnetic noise mainly affects the external environment through two pathways: first, it pollutes the power supply quality of the shared network through conduction via power lines, affecting the normal operation of other sensitive electronic devices within the same system; second, it radiates into space as electromagnetic waves, potentially causing signal transmission errors or performance degradation in surrounding equipment. With the increasing integration of electronic devices, the continuous improvement of signal sensitivity, and the increasingly stringent electromagnetic compatibility regulations worldwide, how to effectively control the electromagnetic interference generated by motors has become an unavoidable key technical issue in product development, which is directly related to the market access, reliability, and user experience of products.

[0003] Existing technologies commonly attempt to add filter networks and transient suppression devices to the external drive circuit or power input of the motor to meet electromagnetic compatibility standards. However, such conventional "end-of-line treatment" solutions have inherent limitations. Because the external filter circuit is physically located far from the source of interference, the parasitic inductance introduced by the connecting wires themselves will severely weaken the filtering effect of high-frequency noise, resulting in poor interference suppression capability for the VHF band. At the same time, the dispersed external components increase the layout complexity and area occupied by the entire circuit board, which not only increases the material and assembly costs but also reduces the reliability of the system. In addition, the response speed and clamping effect of the external protection circuit may be reduced due to path impedance for instantaneous high-voltage surges introduced by the motor power failure back electromotive force or external coupling, resulting in limited interference suppression capability.

[0004] Therefore, it is necessary to provide a motor structure with EMC anti-interference to solve the above-mentioned technical problems. Utility Model Content

[0005] The purpose of this invention is to provide a motor structure with EMC anti-interference to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following solution to the aforementioned technical problems: a motor structure with EMC anti-interference capability, comprising a motor body, the motor body including a metal casing, a rotor, a stator, end covers disposed at both ends of the metal casing, and power supply terminals extending from the end covers. The motor body is internally provided with a filter assembly and a surge absorption assembly. The filter assembly is disposed within the inner cavity of the metal casing and directly connected across the power supply terminals. The surge absorption assembly is disposed within the inner cavity of the metal casing and directly connected across the power supply terminals.

[0007] As a further embodiment of this invention, the filtering component includes at least one ceramic capacitor and one electrolytic capacitor, wherein the ceramic capacitor and the electrolytic capacitor are connected in parallel.

[0008] As a further embodiment of this invention, the surge absorption component is a varistor, and the nominal voltage value of the varistor is higher than the rated operating voltage of the motor.

[0009] As a further embodiment of this utility model, an insulating mounting base is provided on the inner wall of the metal shell, and the filtering component and the surge absorption component are both fixedly mounted on the insulating mounting base.

[0010] As a further embodiment of this utility model, a ferrite magnetic ring is sleeved between the power supply terminal and the internal lead.

[0011] Compared with the prior art, the beneficial effects of this utility model are: By directly integrating the filtering and surge absorption components within the motor's metal casing, this structure achieves direct intervention through the placement of countermeasures components inside the motor. The filtering component provides a nearby, low-impedance discharge path for high-frequency noise, preventing it from escaping to the external power grid through the power supply terminals. The surge absorption component responds instantaneously to abnormal high voltage, absorbing and clamping its energy, thus achieving source control of EMC treatment. Simultaneously, this structure simplifies the complex EMC circuitry into an integral part of the motor, greatly facilitating procurement and assembly for OEMs. They no longer need to design and install additional filtering modules for the motor, simplifying the production process and reducing overall costs. Attached Figure Description

[0012] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 The overall three-dimensional structure of this utility model Figure 1 ; Figure 2 The overall three-dimensional structure of this utility model Figure 2 ; Figure 3This is a schematic diagram of the main structure of the motor of this utility model; Figure 4 This is a schematic diagram of the internal structure of the insulating mounting base of this utility model.

[0013] The attached diagram lists the components represented by each number as follows: 1. Motor body; 101. Metal casing; 102. End cover; 103. Power supply terminal block; 2. Filter assembly; 201. Ceramic capacitor; 202. Electrolytic capacitor; 4. Insulating mounting base; 5. Ferrite magnetic ring; 6. Rotor. Detailed Implementation

[0014] The present invention will be further described below with reference to the embodiments.

[0015] Please see Figure 1-4 This utility model provides a motor structure with EMC anti-interference, including a motor body 1. The motor body 1 includes a metal shell 101, a rotor 6, a stator, end caps 102 disposed at both ends of the metal shell 101, and power terminals 103 led out from the end caps 102. A filter component 2 and a surge absorption component are disposed inside the motor body 1. The filter component 2 is disposed in the inner cavity of the metal shell 101 and directly connected across the power terminals 103. The surge absorption component is disposed in the inner cavity of the metal shell 101 and directly connected across the power terminals 103. The filter component 2 and the surge absorption component are directly built into the metal shell 101 of the motor. This structure achieves the most direct intervention by directly arranging countermeasures components inside the motor. The filter component 2 is responsible for providing a nearby, low-impedance discharge circuit for high-frequency noise, preventing it from escaping to the external power grid through the power terminal 103. The surge absorption component is responsible for responding instantaneously to abnormal high voltage and absorbing and clamping its energy, thus achieving source control of EMC treatment. At the same time, this structure simplifies the complex EMC circuit into an inherent component of the motor, greatly facilitating the procurement and assembly of the complete machine manufacturer. They no longer need to design and install additional filter modules for the motor, simplifying the production process and reducing overall costs.

[0016] Further as Figure 4As shown, it is worth noting that the filter component 2 includes at least one ceramic capacitor 201 and one electrolytic capacitor 202, which are connected in parallel. The ceramic capacitor 201 has extremely low equivalent series inductance and resistance, and its high-frequency characteristics are excellent, effectively absorbing extremely high-frequency noise generated by electrical sparks. The electrolytic capacitor 202 has a larger capacitance and is mainly responsible for smoothing large current fluctuations during motor operation and absorbing relatively low-frequency interference. Using both in parallel forms a wideband LC filter network in principle, where L is the distributed inductance. This achieves full-spectrum noise suppression from low to high frequencies. This composite capacitor structure overcomes the limitations of using a single type of capacitor, effectively filtering out both low-frequency current ripple and high-frequency spike noise generated by the motor. This significantly improves the product's passability in demanding EMC conducted emission tests. Simultaneously, this integrated design ensures the shortest connection path between the capacitor and the motor terminals, minimizing parasitic parameters and guaranteeing optimal filtering performance.

[0017] Further as Figure 3 and Figure 4 As shown, it is worth noting that the surge absorption component is a varistor, whose nominal voltage value is higher than the motor's rated operating voltage. The working principle of the varistor is that when the voltage across its terminals is lower than its nominal voltage, it presents a high resistance state and has almost no effect on the circuit. When it encounters a motor power failure backflow or an external surge voltage that exceeds its nominal voltage, its impedance drops sharply, and it conducts instantaneously, absorbing the dangerous surge energy and converting it into heat energy. This firmly clamps the voltage between the motor terminals to a safe level, ensuring that the varistor is absolutely in the off state during normal motor operation, including within the allowable voltage fluctuation range, and will not malfunction, resulting in losses or heat generation. At the same time, it can also respond promptly to most operational overvoltages and induced lightning surges, not only protecting the external drive circuit from damage but also indirectly protecting the internal insulation system of the motor, thus improving the reliability and lifespan of the entire motor system.

[0018] Further as Figure 4 As shown, it is worth noting that an insulating mounting base 4 is provided on the inner wall of the metal casing 101, and the filter component 2 and the surge absorption component are both fixedly mounted on the insulating mounting base 4. The insulating mounting base 4 provides a stable and reliable mounting platform for precision electronic components. The motor will inevitably vibrate during operation. If the filter component 2 and the surge absorption component are only fixed by their leads, long-term vibration may cause fatigue fracture of the solder joints or short circuit between the components and the metal casing. The insulating mounting base 4 firmly fixes the components by mechanical means, eliminating the reliability risks caused by vibration.

[0019] Further as Figure 1 , Figure 2 and Figure 3 As shown, it is worth noting that a ferrite magnetic ring 5 is sleeved between the power supply terminal 103 and the internal leads. Utilizing the characteristics of ferrite material—high impedance at high frequencies and very low impedance at low frequencies and DC—when a common-mode interference current of equal magnitude and direction flows through the wire passing through the magnetic ring, the magnetic ring will exhibit a large inductive reactance, thereby suppressing the passage of the current. This suppresses the high-frequency common-mode noise radiated outward by the motor drive cable as an antenna, further enhancing the suppression capability of high-frequency radiated noise. This gives the motor of this invention a significant advantage in meeting even the most stringent EMC radiation standards.

[0020] In summary: By directly arranging countermeasures components inside the motor, the most direct intervention is achieved. Filter component 2 is responsible for providing a nearby, low-impedance discharge circuit for high-frequency noise, preventing it from escaping to the external power grid through power terminal 103. Surge absorption component is responsible for responding instantaneously to abnormal high voltage, absorbing and clamping its energy, thus achieving source control of EMC treatment. At the same time, this structure simplifies the complex EMC circuit into an inherent component of the motor, greatly facilitating the procurement and assembly of the complete machine manufacturer. They no longer need to design and install additional filter modules for the motor, simplifying the production process and reducing overall costs.

Claims

1. A motor structure with EMC anti-interference, comprising a motor body (1), the motor body (1) comprising a metal casing (101), a rotor (6), a stator, end caps (102) disposed at both ends of the metal casing (101), and power supply terminals (103) extending from the end caps (102), characterized in that, The motor body (1) is provided with a filter component (2) and a surge absorption component. The filter component (2) is located in the inner cavity of the metal shell (101) and is directly connected between the power supply terminals (103). The surge absorption component is located in the inner cavity of the metal shell (101) and is directly connected between the power supply terminals (103).

2. The motor structure with EMC anti-interference as described in claim 1, characterized in that: The filter component (2) includes at least one ceramic capacitor (201) and one electrolytic capacitor (202), wherein the ceramic capacitor (201) and the electrolytic capacitor (202) are connected in parallel.

3. The motor structure with EMC anti-interference as described in claim 2, characterized in that: The surge absorption component is a varistor, and the nominal voltage value of the varistor is higher than the rated operating voltage of the motor.

4. The motor structure with EMC anti-interference as described in claim 3, characterized in that: An insulating mounting base (4) is provided on the inner wall of the metal casing (101), and the filter assembly (2) and the surge absorption assembly are both fixedly installed on the insulating mounting base (4).

5. The motor structure with EMC anti-interference as described in claim 1, characterized in that: A ferrite magnetic ring (5) is sleeved between the power supply terminal (103) and the internal lead.

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