Eddy current sensor and external rotor motor using same

Abstract

The invention relates to the technical field of sensors, and provides an eddy current sensor and an outer rotor motor using the eddy current sensor, the eddy current sensor comprises a target wheel module and a sensing module, the sensing module is fixedly arranged in a casing, and the target wheel module coaxially sleeves the periphery of an outer rotor iron core; the target wheel module comprises a plurality of eddy current sensitive parts arranged in the circumferential direction of the target wheel module, a target wheel is fixed to the outer ring of the motor rotor through a key groove structure to be limited, and when the target wheel module rotates along with the motor rotor, the eddy current sensitive parts are sequentially matched with the sensing area of the sensing module. According to the invention, the detection precision and the control precision of motor operation are improved, the problem that the outer diameter surface of the rotor core jumps too much or cracks in the installation and operation process is avoided, the problem that the target wheel moves circumferentially in the long-term operation process is solved, the zero setting process of the eddy current sensor is optimized, and the detection precision and the control precision of motor operation are improved. And the reliability of the outer rotor motor is improved.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and more specifically, to an eddy current sensor and an external rotor motor using the eddy current sensor. Background Technology

[0002] Eddy current sensors are sensors based on the eddy current effect. The eddy current effect refers to the phenomenon that, according to Faraday's law of electromagnetic induction, when a bulk metal conductor is placed in a changing magnetic field or moves within a magnetic field cutting magnetic lines of force, the magnetic flux through the conductor changes, generating an induced electromotive force (EMF). This EMF forms a current on the conductor's surface, which closes automatically, resembling a eddy current in water, hence the name eddy current. Eddy current sensors have various industrial applications: axial displacement measurement, vibration measurement, eccentricity measurement, differential expansion measurement, speed measurement, rolling bearings, and dynamic monitoring of motor commutator rectifier segments.

[0003] An external rotor motor is a type of motor in which the rotor rotates on the outer layer of the motor, while the stator is installed inside. External rotor motors have a greater moment of inertia than internal rotor motors, making them suitable for high-power, low-speed applications, such as industrial and household appliances. External rotor motors are attracting increasing attention due to their fully enclosed structure, rapid start-up, low power consumption, high speed, excellent efficiency, and long lifespan. How to provide an eddy current sensor solution suitable for external rotor motors is a technical challenge worth considering. Summary of the Invention

[0004] This invention addresses the technical problems existing in the prior art by providing an eddy current sensor and an external rotor motor using the eddy current sensor. The eddy current target wheel can be reasonably and effectively applied to an external rotor motor or other similar rotating components to improve detection and control accuracy.

[0005] According to a first aspect of the present invention, an eddy current sensor is provided, comprising a target wheel module and a sensing module, wherein the sensing module is fixedly disposed and the target wheel module is rotatably disposed; the target wheel module includes a plurality of eddy current sensitive parts disposed along its circumference, wherein when the target wheel module rotates, the plurality of eddy current sensitive parts sequentially engage with the sensing area of ​​the sensing module.

[0006] Based on the above technical solution, the present invention can also be improved as follows.

[0007] Optionally, the target wheel module includes an annular base, with a rotor mounting position on the inner circumference of the annular base and at least one limiting groove on the outer circumference of the annular base; a plurality of eddy current sensing elements are arranged circumferentially and integrated on a mounting ring, the mounting ring being sleeved on the outer circumference of the annular base, such that the plurality of eddy current sensing elements are intermittently arranged on the outer circumference of the annular base, and the mounting ring is adapted to the limiting groove.

[0008] Optionally, the eddy current sensing element is a sensing tooth, and the sensing tooth has magnetic conductivity.

[0009] Optionally, the inner circumference of the mounting ring is provided with at least one limiting key, which is nested with the limiting groove to achieve axial and circumferential limiting of the annular base and the mounting ring.

[0010] Optionally, all of the eddy current sensitive parts are evenly distributed in a circumferential array on the annular base.

[0011] Optionally, the sensing module includes a transmitting coil, a receiving coil, and a chip, wherein the transmitting coil and the receiving coil correspond to the eddy current sensing element;

[0012] The transmitting coil is used to send electromagnetic test signals to the eddy current sensitive part;

[0013] The receiving coil is used to receive the electromagnetic detection signal returned by the eddy current sensing element;

[0014] The chip is used to control the transmitting coil to emit electromagnetic test signals and to process the electromagnetic detection signals.

[0015] Optionally, along the rotation direction of the target wheel module, the sensing area size of the sensing module is larger than the distance between two adjacent eddy current sensing parts.

[0016] According to a second aspect of the present invention, an external rotor motor is provided, which applies the above-mentioned eddy current sensor, including an external rotor core and a housing. The external rotor core, a target wheel module, and a sensing module are disposed within the housing. The external rotor core is coaxially nested on the inner circumferential surface of the target wheel module. The sensing module is fixedly disposed inside the housing, and the terminal of the sensing module penetrates through the housing. The sensing area of ​​the sensing module and any of the eddy current sensitive parts are arranged along the axial direction of the external rotor core.

[0017] Optionally, the axial dimension of the annular base is not less than the axial dimension of the rotor, and the inner circumference of the annular base of the target wheel module covers the outer circumferential surface of the rotor.

[0018] Optionally, the sensing module is provided with a sealing structure, which is fixedly disposed between the sensing module and the housing.

[0019] This invention provides an eddy current sensor and an external rotor motor using the sensor. Eddy currents can be applied rationally and effectively to the rotating component being measured (e.g., an external rotor motor). A target wheel module is effectively fixed to the outer ring of the motor rotor via a keyway structure. When the target wheel module rotates synchronously with the rotating component (e.g., the rotor of the external rotor motor), the sensing module detects the eddy current changes in various circumferentially sensitive parts of the target wheel module in real time, allowing for the calculation of the real-time operating status of the rotating component. This invention improves the ease of target wheel installation and prevents circumferential and axial movement problems that may occur during long-term rotation. It also achieves a fixed angle between the eddy current target wheel and the sensing module, greatly improving the zeroing convenience of the eddy current sensor and ensuring that the gap between the target wheel and the sensor is within the required range. This invention can improve the detection accuracy of rotating component operation and further enhance the control accuracy of the rotating component's rotational motion. Attached Figure Description

[0020] Figure 1 A schematic diagram illustrating the rotor cooperation relationship between an eddy current sensor and an external rotor motor, provided as an embodiment of the present invention;

[0021] Figure 2(a) is a schematic diagram of the target wheel module structure provided in an embodiment of the present invention, and Figure 2(b) is a schematic diagram of the enlarged cross-sectional structure of the target wheel module provided in an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the sensing module structure provided in an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the functional modules of the sensing module provided in an embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of an external rotor motor structure provided in an embodiment of the present invention.

[0025] The attached diagram lists the components represented by each number as follows:

[0026] 1. Target wheel module, 101. Eddy current sensing element, 101a. Sensing tooth, 101b. Limit key, 101b'. Limit key end face, 102. Annular base, 102a. Limit groove, 102a'. Limit groove end face, 2. Sensing module, 201. Transmitting coil, 202. Receiving coil, 203. Chip, 204. Terminal, 3. Outer rotor core, 4. Housing, 401. Connector, 5. Sealing structure. Detailed Implementation

[0027] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be more thorough and complete.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0029] It is understood that spatial relation terms such as "below," "under," "below," "below," "above," "over," etc., can be used here to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as "below" or "under" or "below" of other elements or features will be oriented "over" of other elements or features. Therefore, the exemplary terms "below" and "under" can include both upper and lower orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0030] It should be noted that when one element is considered to be "connected" to another element, it can be directly connected to the other element or connected to the other element through an intermediary element. In the following embodiments, "connection" should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have the transmission of electrical signals or data between them.

[0031] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising,” “including,” or “having,” etc., specify the presence of the stated feature, whole, step, operation, component, part, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof.

[0032] Figure 1 This is a schematic diagram illustrating the cooperation relationship between an eddy current sensor and a rotating component, provided by an embodiment of the present invention. Taking the application of the eddy current sensor in an external rotor motor as an example, Figure 1 The rotating component in the text refers to the rotor of the external rotor motor; the remaining components of the motor are not shown. For example... Figure 1As shown, this embodiment provides an eddy current sensor, including a target wheel module 1 and a sensing module 2. The sensing module 2 is fixedly mounted, while the target wheel module 1 is rotatably mounted. For example, the target wheel module 1 is coaxially fixed with the rotor of an external rotor motor to achieve synchronous rotation. The target wheel module 1 includes a plurality of eddy current sensitive parts 101 arranged along its circumference. When the target wheel module 1 rotates along its axial direction, the sensing area of ​​the sensing module 2 sequentially engages with the sensing areas of the plurality of eddy current sensitive parts 101. The sensing area of ​​the sensing module 2 and any of the eddy current sensitive parts 101 are arranged along the axial direction of the outer rotor core 3 to detect changes in eddy currents, thereby identifying the motor's operating status.

[0033] It is understood that, based on the deficiencies in the background technology, this embodiment of the invention proposes an eddy current sensor. This embodiment of the invention can reasonably and effectively apply the eddy current sensor to an external rotor motor, and can also be applied to other equipment that needs to monitor rotation. Taking its application to an external rotor motor as an example, when the target wheel module 1 rotates synchronously with the rotor of the external rotor motor, the sensing module 2 detects the eddy current changes in each circumferential eddy current sensitive part 101 of the target wheel module 1 in real time, and the real-time operating status of the external rotor motor can be calculated.

[0034] The present invention can improve the rotational motion detection accuracy of rotating components (e.g., external rotor motors) and further improve the rotational motion control accuracy of rotating components (e.g., external rotor motors).

[0035] Figure 2(a) illustrates the structure of the target wheel module 1 in one possible embodiment, combined with Figure 1 As shown in Figure 2(a), the target wheel module 1 includes an annular base 102. The annular base 102 has a rotor mounting position on its inner circumference, allowing it to be coaxially fitted onto the outer circumference of the rotor of the external rotor motor and connected to the rotor in a non-rotating manner, such as by welding, bolting, or keying. This embodiment uses a keying connection as an example, enabling the annular base 102 and the rotor of the external motor to rotate coaxially and synchronously. Multiple eddy current sensing elements 101 are arranged circumferentially and integrated on a mounting ring. The mounting ring is fitted onto the outer circumference of the annular base 102, allowing the multiple eddy current sensing elements 101 to be intermittently positioned on the outer circumference of the annular base 102 and to rotate synchronously with it.

[0036] The eddy current sensing element 101 and the annular base 102 can be integrally connected, or they can be fixedly connected by separate components. This embodiment considers the second case. Specifically, as shown in Figure 2(b), the outer periphery of the annular base 102 is provided with at least one limiting groove 102a. The limiting structure of the inner periphery of the mounting ring is adapted to the limiting groove 102a, thereby realizing the limiting of the mounting ring and the multiple eddy current sensing elements 101.

[0037] The annular base 102 is fitted onto the outer circumference of the motor rotor via a rotor mounting position, which can reinforce the structure of the motor rotor and improve the reliability of the motor. Multiple eddy current sensing elements 101 are intermittently arranged on the outer circumference of the annular base 102 via mounting rings and are limited by a limiting structure. More specifically, as shown in Figure 2(b), the inner circumference of the mounting ring is provided with at least one limiting key 101b, which nests with the limiting groove 102a to achieve axial and circumferential limiting of the annular base 102 and the mounting ring.

[0038] As a preferred embodiment, the limiting key 101b is configured as a flat key structure, and correspondingly, the limiting groove 102a is configured as a flat keyway structure, allowing for better contact and multi-directional limiting. For example, the limiting groove 102a and the limiting key 101b are arranged along the rotor axis, enabling circumferential limiting during rotor operation and preventing circumferential deflection. The end face 102a' of the limiting groove and the end face 101b' of the limiting key abut against each other in a direction perpendicular to the rotor axis, achieving axial limiting on the rotor. This configuration improves the ease of target wheel installation and prevents circumferential and axial movement that may occur during long-term rotation of the target wheel. It also achieves a fixed angle between the eddy current target wheel and the sensing module, greatly improving the zeroing convenience of the eddy current sensor while ensuring that the gap between the target wheel and the sensor is within the required range.

[0039] As the target wheel module 1 rotates with the rotor, multiple eddy current sensing elements 101 sequentially pass through the sensing area of ​​the sensing module 2, intermittently cutting the magnetic field of the sensing area to generate regularly changing eddy currents. The sensing area of ​​the sensing module 2 detects the changes in the magnetic field caused by the changes in eddy currents. Since the number of eddy current sensing elements 101 circumferentially on the annular base 102 is fixed, the rotor speed and / or rotor rotation angle can be deduced based on the number of detected signal changes and the rate of change.

[0040] In one possible embodiment, such as Figure 1 As shown, the axial dimension of the annular base 102 is not less than the axial dimension of the rotating component, such as the axial dimension of the motor rotor core, and the inner circumference of the annular base 102 covers the outer circumference of the rotating component.

[0041] It is understood that the inner circumferential surface of the annular base 102 is coaxial with the outer circumferential surface of the motor rotor, and the annular base 102 completely encloses the rotor core axially. Simultaneously, the mounting rings of the annular base 102 and the multiple eddy current sensing elements 101 are installed and positioned via a keyway structure. The axial ends of the annular base 102 are flush with or extend beyond the end faces of the rotor core. Preferably, the extension height is within 5mm to prevent excessive increase in the axial dimension of the motor and reduce the space occupied by the motor housing 4. The structure of this embodiment ensures that the outer circumference of the rotor core is completely enclosed by the annular base 102 of the target wheel module 1, avoiding excessive runout or cracking of the outer diameter surface of the rotor core during installation and operation. Simultaneously, the keyway fit design prevents circumferential and axial movement that may occur during long-term rotation. Furthermore, it achieves a fixed angle between the eddy current target wheel and the sensor, greatly improving the zeroing convenience of the eddy current sensor. It also ensures that the gap between the target wheel and the sensor is within the required range, enhancing the reliability of the external rotor motor and guaranteeing its reliable operation. Similarly, for applications involving other rotating components, the annular base 102 limits radial dimensional fluctuations, improving the reliability and stability of their operation.

[0042] In one possible embodiment, all the eddy current sensing elements 101 are evenly distributed in a circular array around the annular base 102, so that when the motor rotates one revolution, the change pattern of eddy currents at each position in the circumference is consistent, which is beneficial for the analysis of the detection results and the judgment of abnormal motor operation.

[0043] In one possible embodiment, such as Figure 1 As shown in Figures 2(a) and 2(b), the eddy current sensing element 101 is a sensing tooth 101a, which is magnetically conductive. In specific implementations, based on the principle that the sensing tooth 101a can sense eddy currents, the annular base 102 and the sensing tooth 101a can be set as an integrated structure made of magnetically conductive material, or they can be set as separate structures, with the annular base 102 and the sensing tooth 101a made of different materials.

[0044] It is understood that in this embodiment, the eddy current sensing element 101 is toothed, with gaps between adjacent sensing teeth 101a. Eddy currents are sensed when the sensing teeth 101a pass through the sensing area of ​​the sensing module 2; no eddy currents are sensed when the gaps between the teeth pass through the sensing area of ​​the sensing module 2. The changing pattern of the eddy currents can reflect the real-time operating status of the motor. Theoretically, without considering the response speed of the sensing module 2, the higher the density of the sensing teeth 101a, the higher the detection accuracy.

[0045] In this embodiment, the eddy current sensing part 101 is set in a tooth shape, and the sensing tooth 101a is set on the outer periphery of the annular base 102. If the motor is cooled by coolant, the centrifugal effect of the tooth structure during motor operation can also throw out the coolant near the rotor, accelerate the flow of coolant, improve the heat dissipation effect of the motor, and thus improve the motor life.

[0046] In one possible embodiment, the sensing teeth 101a are sector teeth, and each of the sector teeth has the same outline.

[0047] Understandably, the sector teeth correspond to the sensing area of ​​the sensing module 2. While ensuring an effective spacing between adjacent sensing teeth 101a, the sector teeth have a large eddy current sensing area to guarantee excellent eddy current sensing performance. All sensing teeth 101a use sector teeth with a consistent shape and structure, ensuring consistent eddy current changes detected at all positions along the rotor's circumference. This improves the accuracy of the detection results and makes it easier to identify abnormal situations.

[0048] In one possible embodiment, combining Figure 3 and Figure 4 As shown, the sensing module 2 includes a transmitting coil 201, a receiving coil 202, and a chip 203, wherein the transmitting coil 201 and the receiving coil 202 correspond to the eddy current sensing part 101;

[0049] The transmitting coil 201 is used to generate an alternating magnetic field, for example, towards the sensing area of ​​the eddy current sensing part 101 (e.g., Figure 1 Electromagnetic test signals are emitted from the upper surface of the fan-shaped teeth in the field of view;

[0050] The sensing area of ​​the eddy current sensing part 101 is made of conductive / magnetic material. When the motor rotor rotates, the alternating magnetic field generated by the transmitting coil 201 will induce eddy currents in the conductive material of the eddy current sensing part 101. The reverse magnetic field generated by the eddy current will affect the characteristics of the original magnetic field.

[0051] The receiving coil 202 is used to detect the reverse magnetic field and receive the electromagnetic detection signal returned by the eddy current sensing part 101. That is, by detecting the impedance change or voltage change in the receiving coil 202, the rotational speed and position of the motor rotor can be indirectly measured.

[0052] The chip 203 is used to control the transmitting coil 201 to emit electromagnetic test signals and to process the electromagnetic detection signals. For example, the detected signals are converted into digital pulse signals for processing and analysis by the control system.

[0053] It is understandable that the working principle of the sensing module 2 of the eddy current sensor is based on existing technology, and will not be elaborated here.

[0054] In one possible embodiment, along the rotation direction of the target wheel module 1, the sensing area size of the sensing module 2 is larger than the distance between two adjacent eddy current sensing parts 101.

[0055] Understandably, the sensing area of ​​sensor module 2 has a sufficiently large size to improve detection accuracy.

[0056] Figure 5 This is a simplified schematic diagram of the internal structure of an external rotor motor using the eddy current sensor described in the foregoing embodiments of the present invention. This diagram only shows the components mentioned in this embodiment. Other components that may exist but are not mentioned, such as the motor stator core and motor shaft, are not included. Figure 5 And not shown. For example... Figure 5 As shown, the external rotor motor includes an external rotor core 3 and a housing 4. The external rotor core 3, the target wheel module 1, and the sensing module 2 are disposed inside the housing 4. The external rotor core 3 is coaxially nested on the inner circumferential surface of the target wheel module 1. Multiple eddy current sensing elements 101 of the target wheel module 1 are mounted in the keyway of the annular base 102 through a flat key type limiting structure. The sensing module 2 is fixedly installed inside the housing 4 through a connector 401, and the terminal 204 of the sensing module 2 penetrates through the housing 4. The sensing area of ​​the sensing module 2 and any of the eddy current sensing elements 101 are arranged along the axial direction of the external rotor core 3.

[0057] Understandably, the housing 4 is a sealed structure to prevent internal coolant (such as cooling oil) from leaking out and to improve the insulation protection level of the motor. The wiring terminal 204 of the sensing module 2 passes through the housing 4 and can communicate with external devices (such as a central control unit).

[0058] In one possible embodiment, the sensing module 2 is provided with a sealing structure 5, such as an elastic sealing ring, a sealing gasket, a sealing adhesive, a wave soldering sealing layer, etc. The sealing structure 5 is fixedly disposed between the sensing module 2 and the housing 4 to improve the sealing effect of the motor housing 4.

[0059] To provide a more intuitive explanation of the present invention, an example will be given in a specific implementation scenario.

[0060] In this implementation scenario, the eddy current sensor includes a target wheel module 1 and a sensing module 2. The target wheel module 1 of the eddy current sensor is coaxially mounted on the motor rotor core, and the multiple eddy current sensing parts 101 of the target wheel module 1 are mounted in the keyway of the annular base 102 through a flat key type limiting structure. The sensing module 2 is mounted on the motor housing 4.

[0061] The target wheel module 1 is divided into three areas: area 1, area 2, and area 3. Area 1 is the rotor core mounting area, area 2 is the area for the induction tooth 101a, and area 3 is the area for the flat key type limiting structure. The entire target wheel module 1 is made of magnetically conductive material and is a single component.

[0062] Region 1 is a hollow cylinder with a thickness between 1.5mm and 8mm. It is installed on the outer ring of the motor rotor core. The inner diameter of Region 1 is concentric with the outer diameter of the motor rotor core, and the axial direction of Region 1 completely encloses the rotor core. The two ends of Region 1 are flush with or exceed the two end faces of the rotor core (the exceeding height is within 5mm).

[0063] Region 2 is located on the outer periphery of Region 1 and consists of a circular base and multiple fan-shaped sensing teeth 101a. The circular base is distributed around the outer ring of Region 1. Alternatively, the circular base and the aforementioned hollow cylinder can be considered the same part, referred to as the annular base 102. The axial position of Region 2 within Region 1 can be adjusted according to actual needs. The axial thickness of the circular base is between 0 mm and 10 mm, and the radial width is between 0.5 mm and 10 mm. The fan-shaped sensing teeth 101a are evenly distributed around the outer ring of the circular base, preferably with the axial end faces of the sensing teeth 101a coinciding with the end faces of the circular base. The fan-shaped sensing teeth 101a correspond to the sensing parts of the sensing module 2. The upper surface contour of each fan-shaped tooth is identical. This contour includes, but is not limited to, the outer ring curve of the fan-shaped tooth and the two left and right line segments. The outer ring curve can be a regular or irregular curve.

[0064] Region 3 is located between Region 1 and Region 2 and consists of one or more flat key-type concave-convex connection structures. The width of the protrusion of each flat key-type structure is between approximately 0.5 mm and 2 mm. The upper and lower end faces of the protrusion are flush with or slightly different from the upper and lower end faces of Region 1.

[0065] The sensing module 2 internally includes components such as a transmitting coil 201, a receiving coil 202, and a chip 203. The transmitting coil 201 and the receiving coil 202 correspond to the sensing area of ​​the sensing module 2. The sensing module 2 is radially mounted on the motor housing 4 with screws to ensure the position of the sensing module 2 relative to the target wheel. The sensing area of ​​the sensing module 2 corresponds to the sensing area of ​​the target wheel (i.e., the position of the sensing tooth 101a). To improve the detection effect, it is preferable that the lower surface of the sensor is parallel to the upper surface of the sensing tooth 101a of the target wheel, and the axial gap between them is between 0.1 mm and 5 mm. The width of the sensing area of ​​the sensor should be greater than the distance between two adjacent teeth of the target wheel, and the radial distance from the sensing area of ​​the sensing module 2 to the rotor mounting area of ​​the target wheel module 1 is between 0.1 mm and 5 mm.

[0066] When installing the eddy current sensor on the external rotor motor, it is preferable that the outer circular surface of the external rotor core 3 is completely wrapped by the inner circular surface of the target wheel. The flat key-type limiting structure on the target wheel is installed in the keyway of the annular base 102, which avoids excessive runout or cracking of the outer diameter surface of the rotor core during installation and operation. At the same time, the keyway fit design also prevents circumferential and axial movement problems that may occur during long-term rotation. It also achieves a fixed angle between the eddy current target wheel and the sensor, thereby greatly improving the zeroing convenience of the eddy current sensor and ensuring that the gap between the target wheel and the sensor is within the required range. The housing 4 has a radial opening through which the wiring terminal 204 of the sensing module 2 in the power eddy current sensor passes. Threaded holes are provided on both sides of the opening for tightening screws to install the sensing module 2. The sensing module 2 has a sealing ring, which can lock the sensing module 2 onto the housing and ensure the sealing of the housing.

[0067] By adjusting the axial position of the sensing tooth 101a on the target wheel and the screw mounting position on the sensing module 2, the eddy current sensor can be better adapted to the installation requirements of different motors, enabling the eddy current sensor to be more widely used in the motor industry.

[0068] This invention provides an eddy current sensor and an external rotor motor using the eddy current sensor. The eddy current sensor is applied effectively to an external rotor motor or similar rotating equipment. When the target wheel module 1 rotates synchronously with the rotor of the external rotor motor, the sensing module 2 detects the eddy current changes in each circumferential eddy current sensitive part 101 of the target wheel module 1 in real time, allowing the calculation of the real-time operation of the external rotor motor. The flat key type limiting structure of the target wheel module 1 is installed in the keyway of the annular base 102 of the external rotor motor, achieving a fixed angle between the eddy current target wheel and the sensor, thereby greatly improving the zeroing convenience of the eddy current sensor and ensuring that the gap between the target wheel and the sensor is within the required range. This invention can improve the detection accuracy of the external rotor motor and further improve its control accuracy. This invention also solves the problems of excessive surface runout and cracking of the rotor core during installation and operation, and the circumferential and axial movement of the target wheel during long-term rotation, ensuring reliable motor operation. The sealed mounting structure of the sensing module 2 on the housing ensures the sealing effect of the housing and improves the overall service life of the device.

[0069] It should be noted that the descriptions of each embodiment in the above embodiments have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0070] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0071] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. An eddy current sensor, characterized in that, The system includes a target wheel module (1) and a sensing module (2). The sensing module (2) is fixedly installed, while the target wheel module (1) is rotatably installed. The target wheel module (1) includes a plurality of eddy current sensing elements (101) arranged along its circumference. When the target wheel module (1) rotates, the plurality of eddy current sensing elements (101) sequentially cooperate with the sensing area of ​​the sensing module (2).

2. An eddy current sensor according to claim 1, characterized in that, The target wheel module (1) includes an annular base (102), the inner circumference of which is provided with a rotor mounting position, and the outer circumference of which is provided with at least one limiting groove (102a); a plurality of eddy current sensitive parts (101) are arranged in a circular pattern and integrated on a mounting ring, the mounting ring being sleeved on the outer circumference of the annular base (102), such that the plurality of eddy current sensitive parts (101) are intermittently arranged on the outer circumference of the annular base (102), and the mounting ring is adapted to the limiting groove (102a).

3. An eddy current sensor according to claim 2, characterized in that, The eddy current sensing part (101) is a sensing tooth (101a), which has magnetic conductivity.

4. An eddy current sensor according to claim 2, characterized in that, The inner circumference of the mounting ring is provided with at least one limiting key (101b), which is nested with the limiting groove (102a) to achieve axial and circumferential limiting of the annular base (102) and the mounting ring.

5. An eddy current sensor according to any one of claims 1, characterized in that, All of the eddy current sensitive parts (101) are evenly distributed in a circular array around the annular base (102).

6. An eddy current sensor according to any one of claims 1 to 5, characterized in that, The sensing module (2) includes a transmitting coil (201), a receiving coil (202), and a chip (203), wherein the transmitting coil (201) and the receiving coil (202) correspond to the eddy current sensing part (101); The transmitting coil (201) is used to send an electromagnetic test signal to the eddy current sensing part (101); The receiving coil (202) is used to receive the electromagnetic detection signal returned by the eddy current sensing element (101); The chip (203) is used to control the transmitting coil (201) to emit electromagnetic test signals and to process the electromagnetic detection signals.

7. An eddy current sensor according to any one of claims 1 to 5, characterized in that, Along the rotation direction of the target wheel module (1), the sensing area of ​​the sensing module (2) is larger than the distance between two adjacent eddy current sensing parts (101).

8. An external rotor motor, employing the eddy current sensor as described in any one of claims 1 to 7, characterized in that, The device includes an outer rotor core (3) and a housing (4). The outer rotor core (3), the target wheel module (1), and the sensing module (2) are disposed inside the housing (4). The outer rotor core (3) is coaxially nested on the target wheel module (1). The sensing module (2) is fixedly disposed inside the housing (4), and the terminal (204) of the sensing module (2) penetrates the housing (4). The sensing area of ​​the sensing module (2) and any of the eddy current sensing parts (101) are arranged along the axial direction of the outer rotor core (3).

9. An external rotor motor according to claim 8, characterized in that, The target wheel module (1) covers the outer circumferential surface of the outer rotor core (3).

10. An eddy current sensor according to claim 8 or 9, characterized in that, A sealing structure (5) is provided between the sensing module (2) and the housing (4).

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